@phdthesis{Benz2024, author = {Benz, Eleanor}, title = {The advisory function of the Inter-American Court of Human Rights}, series = {Beitr{\"a}ge zum ausl{\"a}ndischen {\"o}ffentlichen Recht und V{\"o}lkerrecht}, volume = {329}, journal = {Beitr{\"a}ge zum ausl{\"a}ndischen {\"o}ffentlichen Recht und V{\"o}lkerrecht}, publisher = {Nomos}, address = {Baden-Baden}, issn = {978-3-7489-1980-3}, doi = {10.5771/9783748919803}, school = {Universit{\"a}t Potsdam}, pages = {478}, year = {2024}, abstract = {How do the rights of same-sex couples have to be ensured by states, and which kind of environmental obligations are induced by the right to life and to personal integrity? Questions as diverse and far-reaching as these are regularly dealt with by the Inter-American Court of Human Rights in its advisory function. This book is the first comprehensive, non-Spanish-written treatise on the advisory function of this Court. It analyzes the scope of the Court's advisory jurisdiction and its procedural practice in comparison with that of other international courts. Moreover, the legal effects of the Court's advisory opinions and the question when the Court should better reject a request for an advisory opinion are examined.}, language = {en} } @phdthesis{Jahns2024, author = {Jahns, Esther}, title = {Diglossic translanguaging}, series = {Language and Social Life [LSL]}, volume = {33}, journal = {Language and Social Life [LSL]}, publisher = {de Gruyter Mouton}, address = {Berlin}, isbn = {978-3-11-132246-9}, doi = {10.1515/9783111322674}, school = {Universit{\"a}t Potsdam}, pages = {XI, 245}, year = {2024}, abstract = {This book examines how German-speaking Jews living in Berlin make sense and make use of their multilingual repertoire. With a focus on lexical variation, the book demonstrates how speakers integrate Yiddish and Hebrew elements into German for indexing belonging and for positioning themselves within the Jewish community. Linguistic choices are shaped by language ideologies (e.g., authenticity, prescriptivism, nostalgia). Speakers translanguage when using their multilingual repertoire, but do so in a diglossic way, using elements from different languages for specific domains}, language = {en} } @phdthesis{Rinne2024, author = {Rinne, Theresa Charlotte}, title = {The effects of nutrients on bone stem cell function and regeneration}, school = {Universit{\"a}t Potsdam}, pages = {V, 134}, year = {2024}, abstract = {Aging is associated with bone loss, which can lead to osteoporosis and high fracture risk. This coincides with the enhanced formation of bone marrow adipose tissue (BMAT), suggesting a negative effect of bone marrow adipocytes on skeletal health. Increased BMAT formation is also observed in pathologies such as obesity, type 2 diabetes and osteoporosis. However, a subset of bone marrow adipocytes forming the constitutive BMAT (cBMAT), arise early in life in the distal skeleton, contain high levels of unsaturated fatty acids and are thought to provide a physiological function. Regulated BMAT (rBMAT) forms during aging and obesity in proximal regions of the bone and contain a large proportion of saturated fatty acids. Paradoxically, BMAT accumulation is also enhanced during caloric restriction (CR), a life-span extending dietary intervention. This indicates, that different types of BMAT can form in response to opposing nutritional stimuli with potentially different functions. To this end, two types of nutritional interventions, CR and high fat diet (HFD), that are both described to induce BMAT accumulation were carried out. CR markedly increased BMAT formation in the proximal tibia and led to a higher proportion of unsaturated fatty acids, making it similar to the physiological cBMAT. Additionally, proximal and diaphyseal tibia regions displayed higher adiponectin expression. In aged mice, CR was associated with an improved trabecular bone structure. Taken together, these findings demonstrate, that the type of BMAT that forms during CR might provide beneficial effects for local bone stem/progenitor cells and metabolic health. The HFD intervention performed in this thesis showed no effect on BMAT accumulation and bone microstructure. RNA Seq analysis revealed alterations in the composition of the collagen-containing extracellular matrix (ECM). In order to investigate the effects of glucose homeostasis on osteogenesis, differentiation capacity of immortalized multipotent mesenchymal stromal cells (MSCs) and osteochondrogenic progenitor cells (OPCs) was analyzed. Insulin improved differentiation in both cell types, however, combination of with a high glucose concentration led to an impaired mineralization of the ECM. In the MSCs, this was accompanied by the formation of adipocytes, indicating negative effects of the adipocytes formed during hyperglycemic conditions on mineralization processes. However, the altered mineralization pattern and structure of the ECM was also observed in OPCs, which did not form any adipocytes, suggesting further negative effects of a hyperglycemic environment on osteogenic differentiation. In summary, the work provided in this thesis demonstrated that differentiation commitment of bone-resident stem cells can be altered through nutrient availability, specifically glucose. Surprisingly, both high nutrient supply, e.g. the hyperglycemic cell culture conditions, and low nutrient supply, e.g. CR, can induce adipogenic differentiation. However, while CR-induced adipocyte formation was associated with improved trabecular bone structure, adipocyte formation in a hyperglycemic cell-culture environment hampered mineralization. This thesis provides further evidence for the existence of different types of BMAT with specific functions.}, language = {en} } @phdthesis{Ronneberger2024, author = {Ronneberger, Sebastian}, title = {Nanolayer Fused Deposition Modeling (NanoFDM)}, school = {Universit{\"a}t Potsdam}, pages = {170}, year = {2024}, language = {en} } @phdthesis{Kanehira2023, author = {Kanehira, Yuya}, title = {Versatile DNA origami based SERS substrates for spectroscopic applications}, pages = {115}, year = {2023}, language = {en} } @phdthesis{Grohmann2024, author = {Grohmann, Nils-Hendrik}, title = {Strengthening the UN Human Rights Treaty Bodies}, series = {Jus Internationale et Europaeum}, journal = {Jus Internationale et Europaeum}, number = {202}, publisher = {Mohr Siebeck}, address = {T{\"u}bingen}, isbn = {978-3-16-162825-2}, issn = {1861-1893}, doi = {10.1628/978-3-16-162826-9}, pages = {XV, 315}, year = {2024}, abstract = {Nils-Hendrik Grohmann besch{\"a}ftigt sich mit dem noch andauernden St{\"a}rkungsprozess der UN-Menschenrechtsvertragsorgane. Er analysiert, welche rechtlichen Befugnisse die Aussch{\"u}sse haben, ob sie von sich aus Vorschl{\"a}ge einbringen k{\"o}nnen und inwieweit sie ihre Verfahrensweisen bisher aufeinander abgestimmt haben. Ein weiterer Schwerpunkt liegt auf der Zusammenarbeit zwischen den verschiedenen Aussch{\"u}ssen und der Frage, welche Rolle das Treffen der Vorsitzenden bei der St{\"a}rkung spielen kann.}, language = {en} } @phdthesis{Henning2024, author = {Henning, Thorsten}, title = {Cross-sectional associations of dietary biomarker patterns with health and nutritional status}, school = {Universit{\"a}t Potsdam}, pages = {111}, year = {2024}, language = {en} } @phdthesis{Kersting2024, author = {Kersting, Katerina}, title = {Development of a CRISPR/Cas gene editing technique for the coccolithophore Chrysotila carterae}, school = {Universit{\"a}t Potsdam}, pages = {137}, year = {2024}, language = {en} } @phdthesis{Stechemesser2023, author = {Stechemesser, Annika}, title = {Human behaviour in a warming world}, school = {Universit{\"a}t Potsdam}, pages = {339}, year = {2023}, language = {en} } @phdthesis{You2024, author = {You, Lili}, title = {Chloroplast engineering for recombinant protein production and stress protection}, school = {Universit{\"a}t Potsdam}, pages = {133}, year = {2024}, language = {en} } @phdthesis{Szekely2024, author = {Sz{\´e}kely, Andr{\´a}s Csaba}, title = {Long-distance circadian coordination via a phloem-delivered mobile transcript}, school = {Universit{\"a}t Potsdam}, pages = {105}, year = {2024}, language = {en} } @phdthesis{Melliger2024, author = {Melliger, Marc Andr{\´e}}, title = {Effects of exposing renewables to the market}, school = {Universit{\"a}t Potsdam}, pages = {xi, 139}, year = {2024}, abstract = {Electricity production contributes to a significant share of greenhouse gas emissions in Europe and is thus an important driver of climate change. To fulfil the Paris Agreement, the European Union (EU) needs a rapid transition to a fully decarbonised power production system. Presumably, such a system will be largely based on renewables. So far, many EU countries have supported a shift towards renewables such as solar and wind power using support schemes, but the economic and political context is changing. Renewables are now cheaper than ever before and have become cost-competitive with conventional technologies. Therefore, European policymakers are striving to better integrate renewables into a competitive market and to increase the cost-effectiveness of the expansion of renewables. The first step was to replace previous fixed-price schemes with competitive auctions. In a second step, these auctions have become more technology-open. Finally, some governments may phase out any support for renewables and fully expose them to the competitive power market. However, such policy changes may be at odds with the need to rapidly expand renewables and meet national targets due to market characteristics and investors' risk perception. Without support, price risks are higher, and it may be difficult to meet an investor's income expectations. Furthermore, policy changes across different countries could have unexpected effects if power markets are interconnected and investors able to shift their investments. Finally, in multi-technology auctions, technologies may dominate, which can be a risk for long-term power system reliability. Therefore, in my thesis, I explore the effects of phasing out support policies for renewables, of coordinating these phase-outs across countries, and of using multi-technology designs. I expand the public policy literature about investment behaviour and policy design as well as policy change and coordination, and I further develop an agent-based model. The main questions of my thesis are what the cost and deployment effects of gradually exposing renewables to market forces would be and how coordination between countries affects investors' decisions and market prices.. In my three contributions to the academic literature, I use different methods and come to the following results. In the first contribution, I use a conjoint analysis and market simulation to evaluate the effects of phasing out support or reintroducing feed-in tariffs from the perspective of investors. I find that a phase-out leads to investment shifts, either to other still-supported technologies or to other countries that continue to offer support. I conclude that the coordination of policy changes avoids such shifts.. In the second contribution, I integrate the empirically-derived preferences from the first contribution in to an agent-based power system model of two countries to simulate the effects of ending auctions for renewables. I find that this slows the energy transition, and that cross-border effects are relevant. Consequently, continued support is necessary to meet the national renewables targets. In the third contribution, I analyse the outcome of past multi-technology auctions using descriptive statistics, regression analysis as well as case study comparisons. I find that the outcomes are skewed towards single technologies. This cannot be explained by individual design elements of the auctions, but rather results from context-specific and country-specific characteristics. Based on this, I discuss potential implications for long-term power system reliability. The main conclusions of my thesis are that a complete phase-out of renewables support would slow down the energy transition and thus jeopardize climate targets, and that multi-technology auctions may pose a risk for some countries, especially those that cannot regulate an unbalanced power plant portfolio in the long term. If policymakers decide to continue supporting renewables, they may consider adopting technology-specific auctions to better steer their portfolio. In contrast, if policymakers still want to phase out support, they should coordinate these policy changes with other countries. Otherwise, overall transition costs can be higher, because investment decisions shift to still-supported but more expensive technologies.}, language = {en} } @phdthesis{Wojciechowska2022, author = {Wojciechowska, Izabela}, title = {The journey towards the discovery of new protein-metabolite interactions in Arabidopsis thaliana and further functional characterization of selected binding events}, school = {Universit{\"a}t Potsdam}, pages = {150}, year = {2022}, language = {en} } @phdthesis{Kappel2023, author = {Kappel, Sandrine}, title = {Photosynthesis in fluctuating light}, school = {Universit{\"a}t Potsdam}, pages = {172}, year = {2023}, abstract = {Light is the essential energy source for plants to drive photosynthesis. In nature, light availability is highly variable and often fluctuates on very short time scales. As a result, plants developed mechanisms to cope with these fluctuations. Understanding how to improve light use efficiency in natural fluctuating light (FL) conditions is a major target for agronomy. In the first project, we identified an Arabidopsis thaliana plant that showed reduced levels of rapidly inducible non-photochemical quenching (NPQ). This plant was devoid of any T-DNA insertion. Using a mapping-by-sequencing approach, we successfully located the causal genomic region near the end of chromosome 4. Through variant investigations in that region, we identified a deletion of about 20 kb encompassing 9 genes. By complementation analysis, we confirmed that one of the deleted genes, VTC2, is the causal gene responsible for the low NPQ. Loss of VTC2 decreased NPQ particularly in old leaves, with young leaves being only slightly affected. Additionally, ascorbate levels were almost abolished in old leaves, likely causing the NPQ decrease by reducing the activity of the xanthophyll cycle. Although ascorbate levels in younger leaves were reduced compared to wild-type plants, they remained at a comparably higher level. This difference may be due to the VTC2 paralog VTC5, which is expressed at a higher level in young leaves than in old ones. Plants require the PROTON GRADIENT REGULATION 5 (PGR5) protein for survival in FL. pgr5 mutants die because they fail to increase the luminal proton concentration in response to high light (HL) phases. A rapid elevation in ∆pH is needed to slow down electron transport through the Cytochrome b6 f complex (photosynthetic control). In FL, such lack of control in the pgr5 mutants results in photosystem I (PSI) overreduction, reactive oxygen species (ROS) production, and cell death. Decreases in photosystem II (PSII) activity introduced by crossing pgr5 with PSII deficient mutants rescued the lethality of pgr5 in FL. PGR5 was suggested to act as part of the ferredoxin-plastoquinone reductase (FQR), involved in cyclic electron transfer around PSI. However, the proposed molecular role of PGR5 remains highly debated. To learn more about PGR5 function, we performed a forward genetic screen in Arabidopsis thaliana to identify EMS-induced suppressor mutants surviving longer when grown in FL compared to pgr5 mutants (referred to as "suppressor of pgr5 lethality in fluctuating light", splf ). 11 different candidate genes were identified in a total of 22 splf plants. Mutants of seven of these genes in the pgr5 background showed low Fv/Fm values when grown in non-fluctuating low light (LL). Five of these 4genes were previously reported to have a role in PSII biogenesis or function. Two others, RPH1 and a DEAD/DEAH box helicase (AT3G02060), have not been linked to PSII function before. Three of splf candidate genes link to primary metabolism, fructose-2,6-bisphosphatase (F2KP ), udp-glucose pyrophosphorylase 1 (UGP1 ) and ferredoxin-dependent glutamate synthase (Fd-GOGAT ). They are characterized by the fact that they survive longer in FL than pgr5 mutants but do not procede beyond the early vegetative phase and then die.}, language = {en} } @phdthesis{Bulut2023, author = {Bulut, Mustafa}, title = {Assessing the genetic architecture underlying systemic responses to variable environments in crops using multi-omics}, school = {Universit{\"a}t Potsdam}, pages = {180, IV}, year = {2023}, abstract = {Plant metabolism serves as the primary mechanism for converting assimilated carbon into essential compounds crucial for plant growth and ultimately, crop yield. This renders it a focal point of research with significant implications. Despite notable strides in comprehending the genetic principles underpinning metabolism and yield, there remains a dearth of knowledge regarding the genetic factors responsible for trait variation under varying environmental conditions. Given the burgeoning global population and the advancing challenges posed by climate change, unraveling the intricacies of metabolic and yield responses to water scarcity became increasingly important in safeguarding food security. Our research group has recently started to work on the genetic resources of legume species. To this end, the study presented here investigates the metabolic diversity across five different legume species at a tissue level, identifying species-specific biosynthesis of alkaloids as well as iso-/flavonoids with diverse functional groups, namely prenylation, phenylacylation as well as methoxylation, to create a resource for follow up studies investigation the metabolic diversity in natural diverse populations of legume species. Following this, the second study investigates the genetic architecture of drought-induced changes in a global common bean population. Here, a plethora of quantitative trait loci (QTL) associated with various traits are identified by performing genome-wide association studies (GWAS), including for lipid signaling. On this site, overexpression of candidates highlighted the induction of several oxylipins reported to be pivotal in coping with harsh environmental conditions such as water scarcity. Diverging from the common bean and GWAS, the following study focuses on identifying drought-related QTL in tomato using a bi-parental breeding population. This descriptive study highlights novel multi-omic QTL, including metabolism, photosynthesis as well as fruit setting, some of which are uniquely assigned under drought. Compared to conventional approaches using the bi-parental IL population, the study presented improves the resolution by assessing further backcrossed ILs, named sub-ILs. In the final study, a photosynthetic gene, namely a PetM subunit of the cytochrome b6f complex encoding gene, involved in electron flow is characterized in an horticultural important crop. While several advances have been made in model organisms, this study highlights the transition of this fundamental knowledge to horticultural important crops, such as tomato, and investigates its function under differing light conditions. Overall, the presented thesis combines different strategies in unveiling the genetic components in multi-omic traits under drought using conventional breeding populations as well as a diverse global population. To this end, it allows a comparison of either approach and highlights their strengths and weaknesses.}, language = {en} } @phdthesis{Maul2023, author = {Maul, Valeska Joya}, title = {Addressing current challenges of ecosystems in innovation and entrepreneuership}, school = {Universit{\"a}t Potsdam}, pages = {176, XX}, year = {2023}, abstract = {Nowadays, innovative and entrepreneurial activities and their actors are embedded in interdependent systems to drive joint value creation. Innovation ecosystems and entrepreneurial ecosystems have become established system-level concepts in management research to explain how value transpires between different actors and institutions in distinct contexts. Despite the popularity of the concepts, researchers have critiqued their theoretical depth, conceptual distinctiveness, as well as operationalization and measurement (Autio \& Thomas, 2022; Klimas \& Czakon, 2022). Furthermore, in light of current-day challenges, research has yet to address how context impacts innovation and entrepreneurial ecosystems and their actors and elements (Wurth et al., 2022). The aim of this cumulative thesis is to provide a deeper understanding of the conceptualization, operationalization, and measurement of innovation and entrepreneurial ecosystems and investigate how contextual factors can influence the overall ecosystem and its key actors. To this end, bibliometric and empirical-qualitative methods, as well as narrative and systematic literature reviews, are employed. After introducing the research scope and key concepts in Chapter 1, a systematic literature review to operationalize and measure the concept of innovation ecosystems is conducted, and an integrative framework of its composition is introduced in Chapter 2. In Chapter 3, the innovation journal network is outlined by means of science mapping to determine current and emerging research areas characterizing innovation studies. In Chapters 4 and 5, the interplay between the temporal context of the Covid-19 pandemic and the spatial context of entrepreneurial ecosystems is assessed by focusing on the role of organizational resilience and affordances. The findings shed new light on the dynamics and boundaries of entrepreneurial ecosystems as they move between the spatial and digital realm. Building on this, an integrative framework of digital entrepreneurial ecosystems is presented in Chapter 6. The concluding Chapter 7 summarizes my thesis's conceptual, theoretical, and empirical insights, highlighting implications, limitations, and promising future research avenues. The findings of this cumulative thesis contribute to the theoretical and conceptual advancement of ecosystems in innovation and entrepreneurship by providing insights into the measurement and operationalization of its elements. Furthermore, the results show that contextual factors, such as crisis events or institutional circumstances, influence innovation and entrepreneurial ecosystems and their actors, calling for a more nuanced consideration of ecosystem configurations and dynamics. By drawing from the theory of affordances, the elements that actually afford value to the actors and how they shift between the physical and digital realm are portrayed. Based on these findings, this thesis introduces novel frameworks and conceptual advancements of the configurations and boundaries of innovation and (digital) entrepreneurial ecosystems, laying the foundation for a renewed understanding of how to design, orchestrate, and evaluate ecosystems today and in the future.}, language = {en} } @phdthesis{Schaumburg2024, author = {Schaumburg, Josephine}, title = {Men are not better negotiators after all!}, series = {Schriftenreihe zum Verhandlungsmanagement}, volume = {24}, journal = {Schriftenreihe zum Verhandlungsmanagement}, publisher = {Kovac}, address = {Hamburg}, isbn = {978-3-339-13798-2}, issn = {2365-7898}, school = {Universit{\"a}t Potsdam}, pages = {284}, year = {2024}, abstract = {This dissertation examines the lack of clarity in the scientific literature regarding gender and negotiation performance. It is often claimed that men negotiate better than women, yet it is simultaneously emphasized that results strongly depend on context. Through the use of qualitative methods such as content analysis and critical mixed-methods review, the research question: "Are women truly inferior negotiators compared to men?" is addressed. The study comprises a descriptive and an interpretive part. The descriptive section illuminates various interpretations of gender-specific negotiation theory among citing authors, with 67\% arguing for a general superiority of men. However, given the high variance in gender-specific differences, the focus should instead be on the context-dependency of negotiation performance. Generalized statements can be made within contexts, but not across them. In the interpretive section, several factors contributing to this misinterpretation are highlighted, including discrepancies in the definition of negotiation performance and distortions in research communication.. From a scientific perspective, this study underscores the need for a nuanced sociological analysis and warns against the one-sided acceptance of inaccurate scientific interpretations. From a practical standpoint, it amplifies the voices of women affected by biased research paradigms. Overall, the dissertation clarifies the theory of gender-specific negotiation performance and advocates for the elimination of biases in scientific discourse.}, language = {en} } @phdthesis{Offizier2024, author = {Offizier, Frederike}, title = {The biosecurity individual}, series = {American Culture Studies}, volume = {43}, journal = {American Culture Studies}, publisher = {Transcript}, address = {Bielefeld}, isbn = {978-3-8376-7145-2}, issn = {2747-4380}, doi = {10.14361/9783839471456}, pages = {294}, year = {2024}, abstract = {Discoveries in biomedicine and biotechnology, especially in diagnostics, have made prevention and (self)surveillance increasingly important in the context of health practices. Frederike Offizier offers a cultural critique of the intersection between health, security and identity, and explores how the focus on risk and security changes our understanding of health and transforms our relationship to our bodies. Analyzing a wide variety of texts, from life writing to fiction, she offers a critical intervention on how this shift in the medical gaze produces new paradigms of difference and new biomedically facilitated identities: biosecurity individuals.}, language = {en} } @phdthesis{Bastian2023, author = {Bastian, Martin}, title = {An emergent machine learning approach for seasonal cyclone activity forecasts}, school = {Universit{\"a}t Potsdam}, pages = {135}, year = {2023}, abstract = {Seasonal forecasts are of great interest in many areas. Knowing the amount of precipitation for the upcoming season in regions of water scarcity would facilitate a better water management. If farmers knew the weather conditions of the upcoming summer at sowing time, they could select those cereal species that are best adapted to these conditions. This would allow farmers to improve the harvest and potentially even reduce the amount of pesticides used. However, the undoubted advantages of seasonal forecasts are often opposed by their high degree of uncertainty. The great challenge of generating seasonal forecasts with lead times of several months mainly originates from the chaotic nature of the earth system. In a chaotic system, even tiny differences in the initial conditions can lead to strong deviations in the system's state in the long run. In this dissertation we propose an emergent machine learning approach for seasonal forecasting, called the AnlgModel. The AnlgModel combines the analogue method with myopic feature selection and bootstrapping. To benchmark the abilities of the AnlgModel we apply it to seasonal cyclone activity forecasts in the North Atlantic and Northwest Pacific. The AnlgModel demonstrates competitive hindcast skills with two operational forecasts and even outperforms these for long lead times. In the second chapter we comprehend the forecasting strategy of the Anlg-Model. We thereby analyse the analogue selection process for the 2017 North Atlantic and the 2018 Northwest Pacific seasonal cyclone activity. The analysis shows that those climate indices which are known to influence the seasonal cyclone activity, such as the Ni{\~n}o 3.4 SST, are correctly represented among the selected analogues. Furthermore the selected analogues reflect large-scale climate patterns that were identified by expert reports as being determinative for these particular seasons. In the third chapter we analyse the features that are used by the AnlgModel for its predictions. We therefore inspect the feature relevance (FR). The FR patterns learned by the AnlgModel show a high congruence with the predictor regions used by the operational forecasts. However, the AnlgModel also discovered new features, such as the SST anomaly in the Gulf of Guinea during November. This SST pattern exhibits a remarkably high predictive potential for the upcoming Atlantic hurricane activity. In the final chapter we investigate potential mechanisms, that link two of these regions with high feature relevance to the Atlantic hurricane activity. We mainly focus on ocean surface transport. The ocean surface flow paths are calculated using Lagrangian particle analysis. We demonstrate that the FR patterns in the region of the Canary islands do not correspond with ocean surface transport. It is instead likely that these FR patterns fingerprint a wind transport of latent heat. The second region to be studied is situated in the Gulf of Guinea. Our analysis shows that the FR patterns seen there do fingerprint ocean surface transport. However, our simulations also show that at least one other mechanism is involved in linking the Gulf of Guinea SST anomaly in November to the hurricane activity of the upcoming season. In this work the AnlgModel does not only demonstrate its outstanding forecast skills but also shows its capabilities as research tool for detecting oceanic and atmospheric mechanisms.}, language = {en} } @phdthesis{Pankaj2023, author = {Pankaj, Rishabh}, title = {Epigenetic reprogramming of seed development}, school = {Universit{\"a}t Potsdam}, pages = {182}, year = {2023}, abstract = {The development of seeds in angiosperms starts with a complex process of double fertilization, involving the fusion of the maternal egg cell and central cell with two paternal sperm cells. This gives rise to the embryo and the nourishing endosperm, which are then enclosed by the seed coat, derived from the maternal integuments. The growth of the seed coat in Arabidopsis thaliana (Arabidopsis) is actively inhibited before fertilization by epigenetic regulators known as Polycomb Group (PcG) proteins. These proteins deposit a repressive histone mark called H3K27me3, which must be removed to enable seed coat formation. In this thesis, I explored the mechanism of removal of H3K27me3 marks from the integument cells following fertilization, which allows for seed coat formation. We hypothesized that this removal should be primarily facilitated by histone demethylases from the JMJ family and potentially influenced by the plant hormones Brassinosteroids (BRs). This hypothesis was supported by the expression patterns of the JMJ protein REF6 and of BR related genes, which are specifically expressed in the integuments and in the seed coat. Moreover, mutations in both these pathways lead to developmental defects, such as reduced ovule viability and delayed seed coat growth. Our research provides evidence suggesting that BR signalling is likely involved in recruiting JMJ-type histone demethylases to target loci responsible for seed coat growth. Moreover, we have discovered an additional pathway through which BRs regulate seed coat development, independent of their influence on H3K27me3 marks. This finding emphasizes the diverse roles of BRs in coordinating seed development, extending beyond their well-known involvement in plant growth and development. Furthermore, I explored the role of another epigenetic mark, DNA methylation, in fertilization-independent (or autonomous) seed formation in Arabidopsis. For this, we utilized epigenetic Recombinant Inbred Lines (epiRILs) and thus identified an epigenetic Quantitative Trait Locus (epiQTL) on chromosome II, potentially responsible for the larger autonomous seed size observed in DNA methylation mutants. Overall, this thesis significantly enhances our comprehension of the intricate relationship between epigenetic modifications, hormonal signaling, and plant reproductive processes. It offers valuable insights into the genetic mechanisms governing both sexual and asexual seed formation, while also presenting potential avenues for the engineer of advantageous traits in agricultural crops.}, language = {en} } @phdthesis{BastosLima2023, author = {Bastos Lima, Rita}, title = {Seed coat-derived brassnosteroids non-cell autonomously regulate endosperm development}, school = {Universit{\"a}t Potsdam}, pages = {157}, year = {2023}, language = {en} } @phdthesis{Kulshreshtha2023, author = {Kulshreshtha, Ritika}, title = {Dissecting the functional of role of microtubule and cellulose microfibril patterning during flower development in Arabidopsis}, school = {Universit{\"a}t Potsdam}, pages = {215}, year = {2023}, language = {en} } @phdthesis{SantosBruss2020, author = {Santos Bruss, Sara Morais dos}, title = {Feminist solidarities after modulation}, publisher = {punctum books}, address = {Brooklyn, NY}, isbn = {978-1-68571-146-7}, doi = {10.53288/0397.1.00}, school = {Universit{\"a}t Potsdam}, pages = {xiii, 380}, year = {2020}, abstract = {Feminist Solidarities after Modulation produces an intersectional analysis of transnational feminist movements and their contemporary digital frameworks of identity and solidarity. Engaging media theory, critical race theory, and Black feminist theory, as well as contemporary feminist movements, this book argues that digital feminist interventions map themselves onto and make use of the multiplicity and ambiguity of digital spaces to question presentist and fixed notions of the internet as a white space and technologies in general as objective or universal. Understanding these frameworks as colonial constructions of the human, identity is traced to a socio-material condition that emerges with the modernity/colonialism binary. In the colonial moment, race and gender become the reasons for, as well as the effects of, technologies of identification, and thus need to be understood as and through technologies. What Deleuze has called modulation is not a present modality of control, but is placed into a longer genealogy of imperial division, which stands in opposition to feminist, queer, and anti-racist activism that insists on non-modular solidarities across seeming difference. At its heart, Feminist Solidarities after Modulation provides an analysis of contemporary digital feminist solidarities, which not only work at revealing the material histories and affective ""leakages"" of modular governance, but also challenges them to concentrate on forms of political togetherness that exceed a reductive or essentialist understanding of identity, solidarity, and difference.}, language = {en} } @phdthesis{Hu2022, author = {Hu, Changqiong}, title = {Characterization of the role of stress - responsive NAC transcription factors ANAC055 and ATAF1}, school = {Universit{\"a}t Potsdam}, pages = {XI, 106}, year = {2022}, language = {en} } @phdthesis{Machani2023, author = {Machani, Fridah Gechemba}, title = {Functional analysis of ATAF1 and ANAC032 NAC transcription factors in response to nitrogen Supply in Arabidopsis thaliana}, school = {Universit{\"a}t Potsdam}, pages = {126}, year = {2023}, language = {en} } @phdthesis{RomeroPrada2023, author = {Romero Prada, Lorena Margarita}, title = {Crop improvement towards oxidative stress}, school = {Universit{\"a}t Potsdam}, pages = {155}, year = {2023}, language = {en} } @phdthesis{Sharma2023, author = {Sharma, Anjali}, title = {Optical manipulation of multi-responsive microgels}, school = {Universit{\"a}t Potsdam}, pages = {207}, year = {2023}, abstract = {This dissertation focuses on the understanding of the optical manipulation of microgels dispersed in aqueous solution of azobenzene containing surfactant. The work consists of three parts where each part is a systematic investigation of the (1) photo-isomerization kinetics of the surfactant in complex with the microgel polymer matrix, (2) light driven diffusiosmosis (LDDO) in microgels and (3) photo-responsivity of microgel on complexation with spiropyran. The first part comprises three publications where the first one [P1] investigates the photo-isomerization kinetics and corresponding isomer composition at a photo-stationary state of the photo-sensitive surfactant conjugated with charged polymers or micro sized polymer networks to understand the structural response of such photo-sensitive complexes. We report that the photo-isomerization of the azobenzene-containing cationic surfactant is slower in a polymer complex compared to being purely dissolved in an aqueous solution. The surfactant aggregates near the polyelectrolyte chains at concentrations much lower than the bulk critical micelle concentration. This, along with the inhibition of the photo-isomerization kinetics due to steric hindrance within the densely packed aggregates, pushes the isomer-ratio to a higher trans-isomer concentration for all irradiation wavelengths. The second publication [P2] combines experimental results and non-adiabatic dynamic simulations for the same surfactant molecules embedded in the micelles with absorption spectroscopy measurements of micellar solutions to uncover the reasons responsible for the slowdown in photo induced trans → cis azobenzene isomerization at concentrations higher than the critical micelle concentration (CMC). The simulations reveal a decrease of isomerization quantum yields for molecules inside the micelles and observes a reduction of extinction coefficients upon micellization. These findings explain the deceleration of the trans → cis switching in micelles of the azobenzene-containing surfactants. Finally, the third publication [P3] focusses on the kinetics of adsorption and desorption of the same surfactant within anionic microgels in the dark and under continuous irradiation. Experimental data demonstrate, that microgels can serve as a selective absorber of the trans isomers. The interaction of the isomers with the gel matrix induces a remotely controllable collapse or swelling on appropriate irradiation wavelengths. Measuring the kinetics of the microgel size response and knowing the exact isomer composition under light exposure, we calculate the adsorption rate of the trans-isomers. The second part comprises two publications. The first publication [P4] reports on the phenomenon of light-driven diffusioosmotic (DO) long-range attractive and repulsive interactions between micro-sized objects, whose range extends several times the size of microparticles and can be adjusted to point towards or away from the particle by varying irradiation parameters such as intensity or wavelength of light. The phenomenon is fueled by the aforementioned photosensitive surfactant. The complex interaction of dynamic exchange of isomers and photo-isomerization rate yields to relative concentrations gradients of the isomers in the vicinity of micro-sized object inducing a local diffusioosmotic (DO) flow thereby making a surface act as a micropump. The second publication [P5] exclusively aims the visualization and investigation of the DO flows generated from microgels by using small tracer particles. Similar to micro sized objects, the flow is able to push adjacent tracers over distances several times larger than microgel size. Here we report that the direction and the strength of the l-LDDO depends on the intensity, irradiation wavelength and the amount of surfactant adsorbed by the microgel. For example, the flow pattern around a microgel is directed radially outward and can be maintained quasi-indefinitely under exposure at 455 nm when the trans:cis ratio is 2:1, whereas irradiation at 365 nm, generates a radially transient flow pattern, which inverts at lower intensities. Lastly, the third part consists of one publication [P6] which, unlike the previous works, reports on the study of the kinetics of photo- and thermo-switching of a new surfactant namely, spiropyran, upon exposure with light of different wavelengths and its interaction with p(NIPAM-AA) microgels. The surfactant being an amphiphile, switches between its ring closed spiropyran (SP) form and ring open merocyanine (MC) form which results in a change in the hydrophilic-hydrophobic balance of the surfactant as MC being a zwitterionic form along with the charged head group, generates three charges on the molecule. Therefore, the MC form of the surfactant is more hydrophilic than in the case of the neutral SP state. Here, we investigate the initial shrinkage of the gel particles via charge compensation on first exposure to SP molecules which results from the complex formation of the molecules with the gel matrix, triggering them to become photo responsive. The size and VPTT of the microgels during irradiation is shown to be a combination of heating up of the solution during light absorption by the surfactant (more pronounced in the case of UV irradiation) and the change in the hydrophobicity of the surfactant.}, language = {en} } @phdthesis{Agarwal2023, author = {Agarwal, Pallavi}, title = {Functional characterization of ROS-responsive genes, ANAC085 and ATR7, in Arabidopsis thaliana}, school = {Universit{\"a}t Potsdam}, pages = {XVII, 169}, year = {2023}, language = {en} } @phdthesis{Peng2023, author = {Peng, Maolin}, title = {The role of prion-like domains in plant temperatur sensing}, school = {Universit{\"a}t Potsdam}, pages = {XVI, 121}, year = {2023}, language = {en} } @phdthesis{Stephan2023, author = {Stephan, Mareike Sophia}, title = {A bacterial mimetic system to study bacterial inactivation and infection}, school = {Universit{\"a}t Potsdam}, pages = {150}, year = {2023}, abstract = {The emerging threat of antibiotic-resistant bacteria has become a global challenge in the last decades, leading to a rising demand for alternative treatments for bacterial infections. One approach is to target the bacterial cell envelope, making understanding its biophysical properties crucial. Specifically, bacteriophages use the bacterial envelope as an entry point to initiate infection, and they are considered important building blocks of new antibiotic strategies against drug-resistant bacteria.. Depending on the structure of the cell wall, bacteria are classified as Gram-negative and Gram-positive. Gram-negative bacteria are equipped with a complex cell envelope composed of two lipid membranes enclosing a rigid peptidoglycan layer. The synthesis machinery of the Gram-negative cell envelope is the target of antimicrobial agents, including new physical sanitizing procedures addressing the outer membrane (OM). It is therefore very important to study the biophysical properties of the Gram-negative bacterial cell envelope. The high complexity of the Gram-negative OM sets the demand for a model system in which the contribution of individual components can be evaluated separately. In this respect, giant unilamellar vesicles (GUVs) are promising membrane systems to study membrane properties while controlling parameters such as membrane composition and surrounding medium conditions. The aim of this work was to develop methods and approaches for the preparation and characterization of a GUV-based membrane model that mimics the OM of the Gram-negative cell envelope. A major component of the OM is the lipopolysaccharide (LPS) on the outside of the OM heterobilayer. The vesicle model was designed to contain LPS in the outer leaflet and lipids in the inner leaflet. Furthermore, the interaction of the prepared LPS-GUVs with bacteriophages was tested. LPS containing GUVs were prepared by adapting the inverted emulsion technique to meet the challenging properties of LPS, namely their high self-aggregation rate in aqueous solutions. Notably, an additional emulsification step together with the adaption of solution conditions was employed to asymmetrically incorporate LPS containing long polysaccharide chains into the artificial membranes. GUV membrane asymmetry was verified with a fluorescence quenching assay. Since the necessary precautions for handling the quenching agent sodium dithionite are often underestimated and poorly described, important parameters were tested and identified to obtain a stable and reproducible assay. In the context of varied LPS incorporation, a microscopy-based technique was introduced to determine the LPS content on individual GUVs and to directly compare vesicle properties and LPS coverage. Diffusion coefficient measurements in the obtained GUVs showed that increasing LPS concentrations in the membranes resulted in decreased diffusivity. Employing LPS-GUVs we could demonstrate that a Salmonella bacteriophage bound with high specificity to its LPS receptor when presented at the GUV surface, and that the number of bound bacteriophages scaled with the amount of presented LPS receptor. In addition to binding, the bacteriophages were able to eject their DNA into the vesicle lumen. LPS-GUVs thus provide a starting platform for bottom-up approaches for the generation of more complex membranes, in which the effects of individual components on the membrane properties and the interaction with antimicrobial agents such as bacteriophages could be explored.}, language = {en} } @phdthesis{Li2023, author = {Li, Xiaoping}, title = {Regulation of starch granule number and morphology in arabidopsis thaliana}, school = {Universit{\"a}t Potsdam}, pages = {116}, year = {2023}, language = {en} } @phdthesis{Koelman2023, author = {Koelman, Liselot A.}, title = {The role of diet in immune health and ageing}, school = {Universit{\"a}t Potsdam}, year = {2023}, language = {en} } @phdthesis{Batti2023, author = {Batti, Anil Dominic}, title = {Schopenhauer's doctrine of salvation in relation to his critique of religion and philosophical teachings}, publisher = {Logos}, address = {Berlin}, isbn = {978-3-83255-735-5}, school = {Universit{\"a}t Potsdam}, pages = {319}, year = {2023}, abstract = {Arthur Schopenhauer (1788-1860) was perhaps the last polymath among the great Germanic philosophers. Switching with ease and elegance between epistemic positions and fields as diverse as idealism and empiricism, fideism and rationalism, realism and nominalism, art and religion, jurisprudence and politics, psychology and occultism, Schopenhauer erected an imposing edifice bearing testimony to his universal learning. This study is an investigation into the very conclusion of Schopenhauer's philosophy and endeavours to answer the following question: did Schopenhauer's doctrine of salvation issue forth organically from his intellectual output or was it annexed to his philosophy as a result of his critical engagement with religion? The labyrinthine paths through which Schopenhauer arrives at the soteriological culmination of his philosophy are subjected to critical assessment; the picture that emerges is of a philosopher who seemed convinced that he had solved some of the most pressing cosmic riddles to have tormented mankind through the ages.}, language = {en} } @phdthesis{Khawaja2023, author = {Khawaja, Muhammad Asim}, title = {Improving earthquake forecast modeling and testing using the multi-resolution grids}, school = {Universit{\"a}t Potsdam}, pages = {107}, year = {2023}, language = {en} } @phdthesis{Sajedi2023, author = {Sajedi, Maryam}, title = {Investigation of metal-halide-perovskites by state-of-the-art synchrotron-radiation methods}, school = {Universit{\"a}t Potsdam}, pages = {xviii, 149}, year = {2023}, abstract = {My thesis chiefly aims to shed light on the favourable properties of LHP semiconductors from the point of view of their electronic structure. Currently, various hypotheses are circulating to explain the exceptionally favourable transport properties of LHPs. Seeking an explanation for the low non-radiative recombination rates and long carrier lifetimes is particularly interesting to the halide perovskites research community. The first part of this work investigates the two main hypotheses that are believed to play a significant role: the existence of a giant Rashba effect and large polarons. The experimental method of ARPES is mainly applied to verify their credibility. The first hypothesis presumes that a giant Rashba effect restricts the recombination losses of the charge carriers by making the band gap slightly indirect. The Rashba effect is based on a strong SOC that could appear in LHPs thanks to incorporating the heavy element Pb in their structure. Earlier experimental work had pointed out this effect at the VBM of a hybrid LHP as a viable explanation for the long lifetimes of the charge carriers. My systematic ARPES studies on hybrid MAPbBr3 and spin-resolved ARPES studies on the inorganic CsPbBr3 disprove the presence of any Rashba effect in the VBM of the reported order of magnitude. Therefore, neither the spin texture nor an indirect band gap character at the VBM in the bulk or at the surface can explain the high efficiency of LHP. In case of existence, this effect is in terms of the Rashba parameter at least a factor of a hundred smaller than previously assumed. The second hypothesis proposes large polaron formation in the electronic structure of LHPs and attributes it to their high defect tolerance and low non-radiative recombination rate. Because the perovskite structure consists of negative and positive ions, polarons of this kind can be expected due to the Coulomb interaction between carriers and the polar lattice at intermediate electron-phonon coupling strength. Their existence is proposed to screen the carriers and defects to avoid recombination and trapping, thus leading to long carrier lifetimes. ARPES results by one group supported this assumption, reporting a 50\% effective mass enhancement over the theoretical effective mass for CsPbBr3 in the orthorhombic structure. The current thesis examines this hypothesis experimentally by photon-energy-dependent ARPES spectra and theoretically by GW band calculations of CsPbBr3 perovskites. The investigation is based on the fact that a polaron contribution in charge transport can become evident by an increase of the effective mass as measured by ARPES over the calculated one without polaron effects. However, my experiments on crystalline CsPbBr3 did not imply a larger effective mass for which one could postulate large polarons. In fact, the effective masses determined from ARPES agree with that of theoretical predictions. The second part of my thesis thoroughly investigates the possibility of spontaneously magnetizing LHPs by introducing Mn2+ ions. Mn doping was reported to cause ferromagnetism in one of the most common LHPs, MAPbI3, mediated by super-exchange. The current work investigates the magnetic properties of a wide concentration range of Mn-doped MAPbI3 and triple-cation films by XAS, XMCD, and SQUID measurements. Based on the XAS line shape and a sum-rule analysis of the XMCD spectra, a pure Mn2+ configuration has been confirmed. Negative Curie temperatures are extracted from fitting the magnetization with a Curie-Weiss law. However, a remanent magnetization, which would be an indication of the absence of ferromagnetism down to 2K. As far as the double exchange is concerned, the element-specific XAS excludes a sufficient amount of Mn3+ as a prerequisite for this mechanism. All the findings show no evidence of significant double exchange or ferromagnetism in Mn-doped LHPs. The magnetic behavior is paramagnetic rather than ferromagnetic. In the dissertation's last chapter, orthorhombic features of CsPbBr3 are revealed by ARPES, including an extra VBM at the Γ-point. The VBM of CsPbBr3 shows a temperature-dependent splitting, which decreases by 190 meV between 38K and 300K and tracks a shift of a saddle point at the cubic M-point. It is possible to reproduce the energy shift using an atomic model with a larger unit cell for room temperature, allowing local inversion symmetry breaking. This indicates the importance of electric dipoles for the inorganic LHPs, which may contribute to their high efficiency by breaking inversion symmetry and a Berry-phase effect.}, language = {en} } @phdthesis{Pietrek2023, author = {Pietrek, Anou F.}, title = {Basic psychological needs and depression in the context of health and exercise}, school = {Universit{\"a}t Potsdam}, year = {2023}, abstract = {Depressive Erkrankungen gehen mit verminderter Lebenszufriedenheit und reduzierter Arbeitsf{\"a}higkeit einher. Die Wartezeit f{\"u}r eine Psychotherapie betr{\"a}gt in Deutschland derzeit zwischen drei und sechs Monaten. Demnach besteht Bedarf an alternativen, gleichwertigen evidenzbasierten Behandlungsm{\"o}glichkeiten, die den Betroffenen niedrigschwellig zug{\"a}nglich gemacht werden. Eine Vielzahl an empirischen Studien belegt die Wirksamkeit von Sport bei leichten und mittelschweren Depressionen. Zur weiterf{\"u}hrenden Konzeption und Qualit{\"a}tssicherung von Sport als Behandlungsoption ist es notwendig die konkreten Wirkmechanismen zu verstehen. Neben physiologischen spielen auch psychologische Faktoren eine Rolle im Wirkungsgeschehen. Als Metatheorie menschlichen Erlebens und Verhaltens bietet die Selbstbestimmungstheorie (engl.: Self-Determination Theory; SDT) einen n{\"u}tzlichen Bezugsrahmen zum Verst{\"a}ndnis psychologischer Wirkmechanismen mit konkreten Ableitungen f{\"u}r die Behandlungspraktik. Die konzeptionelle Erweiterung der SDT um die Frustration psychologischer Grundbed{\"u}rfnisse erweist sich neben der Bed{\"u}rfnisbefriedigung zunehmend als hilfreich bei der Untersuchung von psychischen Erkrankungen. Der erste Teil dieser Dissertation besteht aus zwei Publikationen, die relevante Messinstrumente in dem genannten Kontext validieren. Der erste Fragebogen misst das Ausmaß an allgemein erlebter Befriedigung und Frustration der psychologischen Grundbed{\"u}rfnisse nach Autonomie, Kompetenz und sozialer Eingebundenheit. Der zweite Fragebogen erhebt die erlebte Bed{\"u}rfnisbefriedigung durch die anleitende Person (hier: Sporttherapeut*in). Der zweite Teil der Dissertation umfasst zwei Publikationen, welche die Befriedigung und Frustration der psychologischen Grundbed{\"u}rfnisse bei depressiven Symptomen untersuchen und einordnen. Es werden die Unterschiede im Ausmaß an Bed{\"u}rfnisbefriedigung und Bed{\"u}rfnisfrustration zwischen einer Stichprobe mit Depression mit einer Stichprobe ohne depressive Symptome untersucht. Der Zusammenhang zwischen Bed{\"u}rfnisfrustration und depressiven Symptomen wird im Kontext etablierter pathologischer Prozesse (Emotionsdysregulation, Rumination) eingeordnet. Die Hauptergebnisse dieser Arbeiten zeigen, dass die SDT durch die Erweiterung der Basic Psychological Needs Theory um die Dimension der Bed{\"u}rfnisfrustration ein nun breiteres Spektrum auf dem Gesundheit-Krankheit-Kontinuum abbildet. Dabei fokussiert die SDT auf die psychologische Wirkung von sozialen Umwelten. Neben der Nichterf{\"u}llung der psychologischen Grundbed{\"u}rfnisse ist es vor allem die Bed{\"u}rfnisfrustration, die einen allgemeinen Vulnerabilit{\"a}tsfaktor f{\"u}r das Vorkommen psychologischer Erkrankungen darstellt. Zudem weist die unausgewogene Befriedigung der psychologischen Grundbed{\"u}rfnisse m{\"o}glicherweise auf ein konflikthaftes Erleben zwischen den Bed{\"u}rfnissen hin. F{\"u}r die Behandlungspraktik abzuleiten ist, dass eine autonomieunterst{\"u}tzende Atmosph{\"a}re, die die ausgewogene Befriedigung aller drei Bed{\"u}rfnisse erm{\"o}glicht, zentral f{\"u}r den Behandlungserfolg ist.}, language = {en} } @phdthesis{Baryzewska2023, author = {Baryzewska, Agata W.}, title = {Reconfigurable Janus emulsions as signal transducers for biosensing applications}, school = {Universit{\"a}t Potsdam}, pages = {133}, year = {2023}, language = {en} } @phdthesis{Lian2023, author = {Lian, Tingting}, title = {Efficient activation of peroxymonosulfate by carbon-based catalysts for water purification}, school = {Universit{\"a}t Potsdam}, pages = {167}, year = {2023}, abstract = {The increasing global population has led to a growing demand for cost-effective and eco-friendly methods of water purification. This demand has reached a peak due to the increasing presence of impurities and pollutants in water and a growing awareness of waterborne diseases. Advanced oxidation processes (AOPs) are effective methods to address these challenges, due to the generation of highly reactive radicals, such as sulfate radical (SO4•-), hydroxyl radical (•OH), and/or superoxide radical (•O2-) in oxidation reactions. Relative to conventional hydrogen peroxide (H2O2)-based AOPs for wastewater treatment, the persulfate-related AOPs are receiving increasing attention over the past decades, due to their stronger oxidizing capability and a wider pH working window. Further deployment of the seemingly plausible technology as an alternative for the well-established one in industry, however, necessitates a careful evaluation of compounding factors, such as water matrix effects, toxicological consequences, costs, and engineering challenges, etc. To this end, rational design of efficient and environmentally friendly catalysts constitutes an indispensable pathway to advance persulfate activation efficacy and to elucidate the mechanisms in AOPs, the combined endeavors are expected to provide insightful understanding and guidelines for future studies in wastewater treatment. A dozens of transition metal-based catalysts have been developed for persulfate-related AOPs, while the undesirable metal leaching and poor stability in acidic conditions have been identified as major obstacles. Comparatively, the carbonaceous materials are emerging as alternative candidates, which are characterized by metal-free nature, wide availability, and exceptional resistance to acid and alkali, as well as tunable physicochemical and electronic properties, the combined merits make them an attractive option to overcome the aforementioned limitations in metal-based catalytic systems. This dissertation aims at developing novel carbonaceous materials to boost the activity in peroxymonosulfate (PMS) activation processes. Functionalized carbon materials with metal particles or heteroatoms were constructed and further evaluated in terms of their ability to activate PMS for AOPs. The main contents of this thesis are summarized as follows: (1) Iron oxide-loaded biochar: improving stability and alleviating metal leakage Metal leaching constitutes one of the main drawbacks in using transition metals as PMS activators, which is accompanied by the generation of metal-containing sludge, potentially leading to secondary pollution. Meanwhile, the metal nanoparticles are prone to aggregate, causing rapid decay of catalytic performance. The use of carbons as supports for transition metals could mitigate these deficiencies, because the interaction between metals and carbons could in turn disperse and stabilize metal nanoparticles, thus suppressing the metal leaching. In this work, the environmentally benign lignin with its abundant phenolic groups, which is well known to serve as carbon source with high yields and flexibility, was utilized to load Fe ions. The facile low-temperature pre-treatment pyrolytic strategy was employed to construct a green catalyst with iron oxides embedded in Kraft-lignin-derived biochar (termed as γ-Fe2O3@KC). The γ-Fe2O3@KC was capable of activating PMS to generate stable non-radical species (1O2 and Fe (V)=O) and to enhance electron transfer efficiency. A surface-bound reactive complex (catalyst-PMS*) was identified by electrochemical characterizations and discussed with primary surface-bound radical pairs to explain the contradictions between quenching and EPR detection results. The system also showed encouraging reusability for at least 5 times and high stability at pH 3-9. The low concentration of iron in γ-Fe2O3@KC/PMS system implied that the carbon scaffold of biochar substantially alleviated metal leakage. (2) MOF-derived nanocarbon: new carbon crystals Traditional carbon materials are of rather moderate performance in activation PMS, due to the poor electron transfer capacity within the amorphous structure and limited active sites for PMS adsorption. Herein, we established crystalline nanocarbon materials via a simple NaCl-templated strategy using the monoclinic zeolitic imidazolate framework-8 (ZIF-8) sealed with NaCl crystals as the precursors. Specifically, NaCl captured dual advantages in serving as structure-directing agent during hydrolysis and protective salt reactor to facilitate phase transformation during carbonization. The structure-directing agent NaCl provided a protective and confined space for the evolution of MOF upon carbonization, which led to high doping amounts of nitrogen (N) and oxygen elements (O) in carbon framework (N: 14.16 wt\%, O: 9.6 wt\%) after calcination at a high temperature of 950 oC. We found that N-O co-doping can activate the chemically inert carbon network and the nearby sp2-hybridized carbon atoms served as active sites for adsorption and activation. Besides, the highly crystallized structure with well-established carbon channels around activated carbon atoms could significantly accelerate electron transfer process after initial adsorption of PMS. As such, this crystalline nanocarbon exhibited excellent catalytic kinetics for various pollutants. (3) MOF-derived 2D carbon layers: enhanced mass/electron transfer The two-dimensional (2D) configuration of carbon-based nanosheets with inherent nanochannels and abundant active sites residing on the layer edges or in between the layers, allowed the accessible interaction and close contact between the substrates and reactants, as well as the dramatically improved electron- and mass-transfer kinetics. In this regard, we developed dual-templating strategy to afford 2D assembly of the crystalline carbons, which found efficiency in reinforcing the interactions between the catalyst surface and foreign pollutants. Specifically, we found that the ice crystals and NaCl promoted the evolution of MOF in a 2D fashion during the freezing casting stage, while the later further allowed the formation of a graphitic surface at high calcination temperature, by virtue of the templating effect of molten salt. Due to the highly retained co-doping amounts, N and O heteroatoms created abundant active sites for PMS activation, the 2D configuration of carbon-based nanosheets enable efficient interaction of PMS and pollutants on the surface, which further boosted the kinetics of degradation.}, language = {en} } @phdthesis{LopesFernando2023, author = {Lopes Fernando, Raquel Sofia}, title = {The impact of aging on proteolytic systems, transcriptome and metabolome of slow and fast muscle fiber types}, doi = {10.25932/publishup-60579}, school = {Universit{\"a}t Potsdam}, pages = {XI, 125}, year = {2023}, abstract = {Aging is a complex process characterized by several factors, including loss of genetic and epigenetic information, accumulation of chronic oxidative stress, protein damage and aggregates and it is becoming an emergent drug target. Therefore, it is the utmost importance to study aging and agerelated diseases, to provide treatments to develop a healthy aging process. Skeletal muscle is one of the earliest tissues affected by age-related changes with progressive loss of muscle mass and function from 30 years old, effect known as sarcopenia. Several studies have shown the accumulation of protein aggregates in different animal models, as well as in humans, suggesting impaired proteostasis, a hallmark of aging, especially regarding degradation systems. Thus, different publications have explored the role of the main proteolytic systems in skeletal muscle from rodents and humans, like ubiquitin proteasomal system (UPS) and autophagy lysosomal system (ALS), however with contradictory results. Yet, most of the published studies are performed in muscles that comprise more than one fiber type, that means, muscles composed by slow and fast fibers. These fiber types, exhibit different metabolism and contraction speed; the slow fibers or type I display an oxidative metabolism, while fast fibers function towards a glycolytic metabolism ranging from fast oxidative to fast glycolytic fibers. To this extent, the aim of this thesis sought to understand on how aging impacts both fiber types not only regarding proteostasis but also at a metabolome and transcriptome network levels. Therefore, the first part of this thesis, presents the differences between slow oxidative (from Soleus muscle) and fast glycolytic fibers (Extensor digitorum longus, EDL) in terms of degradation systems and how they cope with oxidative stress during aging, while the second part explores the differences between young and old EDL muscle transcriptome and metabolome, unraveling molecular features. More specifically, the results from the present work show that slow oxidative muscle performs better at maintaining the function of UPS and ALS during aging than EDL muscle, which is clearly affected, accounting for the decline in the catalytic activity rates and accumulation of autophagy-related proteins. Strinkingly, transcriptome and metabolome analyses reveal that fast glycolytic muscle evidences significant downregulation of mitochondrial related processes and damaged mitochondria morphology during aging, despite of having a lower oxidative metabolism compared to oxidative fibers. Moreover, predictive analyses reveal a negative association between aged EDL gene signature and lifespan extending interventions such as caloric restriction (CR). Although, CR intervention does not alter the levels of mitochondrial markers in aged EDL muscle, it can reverse the higher mRNA levels of muscle damage markers. Together, the results from this thesis give new insights about how different metabolic muscle fibers cope with age-related changes and why fast glycolytic fibers are more susceptible to aging than slow oxidative fibers.}, language = {en} } @phdthesis{Valade2023, author = {Valade, Aurelien Niels Valentin}, title = {Unveiling the Local Universe}, school = {Universit{\"a}t Potsdam}, pages = {X, 102}, year = {2023}, language = {en} } @phdthesis{Sarlet2023, author = {Sarlet, Adrien}, title = {Tuning the viscoelasticity of Escherichia coli biofilms}, school = {Universit{\"a}t Potsdam}, pages = {143}, year = {2023}, abstract = {Biofilms are heterogeneous structures made of microorganisms embedded in a self-secreted extracellular matrix. Recently, biofilms have been studied as sustainable living materials with a focus on the tuning of their mechanical properties. One way of doing so is to use metal ions. In particular biofilms have been shown to stiffen in presence of some metal cations and to soften in presence of others. However, the specificity and the determinants of those interactions vary between species. While Escherichia coli is a widely studied model organism, little is known concerning the response of its biofilms to metal ions. In this work, we aimed at tuning the mechanics of E. coli biofilms by acting on the interplay between matrix composition and metal cations. To do so, we worked with E. coli strains producing a matrix composed of curli amyloid fibres or phosphoethanolamine-cellulose (pEtN-cellulose) fibres or both. The viscoelastic behaviour of the resulting biofilms was investigated with rheology after incubation with one of the following metal ion solutions: FeCl3, AlCl3, ZnCl2 and CaCl2 or ultrapure water. We observed that the strain producing both fibres stiffen by a factor of two when exposed to the trivalent metal cations Al(III) and Fe(III) while no such response is observed for the bivalent cations Zn(II) and Ca(II). Strains producing only one matrix component did not show any stiffening in response to either cation, but even a small softening. In order to investigate further the contribution of each matrix component to the mechanical properties, we introduced additional bacterial strains producing curli fibres in combination with non-modified cellulose, non-modified cellulose only or neither component. We measured biofilms produced by those different strains with rheology and without any solution. Since rheology does not preserve the architecture of the matrix, we compared those results to the mechanical properties of biofilms probed with the non-destructive microindentation. The microindentation results showed that biofilm stiffness is mainly determined by the presence of curli amyloid fibres in the matrix. However, this clear distinction between biofilm matrices containing or not containing curli is absent from the rheology results, i.e. following partial destruction of the matrix architecture. In addition, rheology also indicated a negative impact of curli on biofilm yield stress and flow stress. This suggests that curli fibres are more brittle and therefore more affected by the mechanical treatments. Finally, to examine the molecular interactions between the biofilms and the metal cations, we used Attenuated total reflectance - Fourier transform infrared spectroscopy (ATR-FTIR) to study the three E.coli strains producing a matrix composed of curli amyloid fibres, pEtN-cellulose fibres or both. We measured biofilms produced by those strains in presence of each of the aforementioned metal cation solutions or ultrapure water. We showed that the three strains cannot be distinguished based on their FTIR spectra and that metal cations seem to have a non-specific effect on bacterial membranes in absence of pEtN-cellulose. We subsequently conducted similar experiments on purified curli or pEtN-cellulose fibres. The spectra of the pEtN-cellulose fibres revealed a non-valence-specific interaction between metal cations and the phosphate of the pEtN-modification. Altogether, these results demonstrate that the mechanical properties of E. coli biofilms can be tuned via incubation with metal ions. While the mechanism involving curli fibres remains to be determined, metal cations seem to adsorb onto pEtN-cellulose and this is not valence-specific. This work also underlines the importance of matrix architecture to biofilm mechanics and emphasises the specificity of each matrix composition.}, language = {en} } @phdthesis{Kairaliyeva2023, author = {Kairaliyeva, Talmira}, title = {Surfactant adorption at liquid interfaces measured by drop and bubble experiments}, school = {Universit{\"a}t Potsdam}, pages = {VII, 117}, year = {2023}, language = {en} } @phdthesis{Gaetjen2023, author = {G{\"a}tjen, Dominic}, title = {A Pichia pastoris surface display system for the efficient screening of high-producing antibody clones}, school = {Universit{\"a}t Potsdam}, pages = {120}, year = {2023}, abstract = {Pichia pastoris (syn. Komagataella phaffi) is a distinguished expression system widely used in industrial production processes. Recent molecular research has focused on numerous approaches to increase recombinant protein yield in P. pastoris. For example, the design of expression vectors and synthetic genetic elements, gene copy number optimization, or co-expression of helper proteins (transcription factors, chaperones, etc.). However, high clonal variability of transformants and low screening throughput have hampered significant success. To enhance screening capacities, display-based methodologies inherit the potential for efficient isolation of producer clones via fluorescence-activated cell sorting (FACS). Therefore, this study focused on developing a novel clone selection method that is based on the non-covalent attachment of Fab fragments on the P. pastoris cell surface to be applicable for FACS. Initially, a P. pastoris display system was developed, which is a prerequisite for the surface capture of secreted Fabs. A Design of Experiments approach was applied to analyze the influence of various genetic elements on antibody fragment display. The combined P. pastoris formaldehyde dehydrogenase promoter (PFLD1), Saccharomyces cerevisiae invertase 2 signal peptide (ScSUC2), - agglutinin (ScSAG1) anchor protein, and the ARS of Kluyveromyces lactis (panARS) conferred highest display levels. Subsequently, eight single-chain variable fragments (scFv) specific for the constant part of the Fab heavy or light chain were individually displayed in P. pastoris. Among the tested scFvs, the anti-human CH1 IgG domain scFv allowed the most efficient Fab capture detected by flow cytometry. Irrespective of the Fab sequence, exogenously added as well as simultaneously secreted Fabs were successfully captured on the cell surface. Furthermore, Fab secretion capacities were shown to correlate to the level of surface-bound Fabs as demonstrated for characterized producer clones. Flow-sorted clones presenting high amounts of Fabs showed an increase in median Fab titers (factor of 21 to 49) compared to unsorted clones when screened in deep-well plates. For selected candidates, improved functional Fab yields of sorted cells vs. unsorted cells were confirmed in an upscaled shake flask production. Since the scFv capture matrix was encoded on an episomal plasmid with inherently unstable autonomously replicating sequences (ARS), efficient plasmid curing was observed after removing the selective pressure. Hence, sorted clones could be immediately used for production without the need to modify the expression host or vector. The resulting switchable display/secretion system provides a streamlined approach for the isolation of Fab producers and subsequent Fab production.}, language = {en} } @phdthesis{Kotz2022, author = {Kotz, Maximilian}, title = {The economic costs of climate change}, school = {Universit{\"a}t Potsdam}, pages = {279}, year = {2022}, language = {en} } @phdthesis{Apriyanto2023, author = {Apriyanto, Ardha}, title = {Analysis of starch metabolism in source and sink tissue of plants}, school = {Universit{\"a}t Potsdam}, pages = {166}, year = {2023}, abstract = {Starch is an essential biopolymer produced by plants. Starch can be made inside source tissue (such as leaves) and sink tissue (such as fruits and tubers). Nevertheless, understanding how starch metabolism is regulated in source and sink tissues is fundamental for improving crop production. Despite recent advances in the understanding of starch and its metabolism, there is still a knowledge gap in the source and sink metabolism. Therefore, this study aimed to summarize the state of the art regarding starch structure and metabolism inside plants. In addition, this study aimed to elucidate the regulation of starch metabolism in the source tissue using the leaves of a model organism, Arabidopsis thaliana, and the sink tissue of oil palm (Elaeis guineensis) fruit as a commercial crop. The research regarding the source tissue will focus on the effect of the blockage of starch degradation on the starch parameter in leaves, especially in those of A. thaliana, which lack both disproportionating enzyme 2 (DPE2) and plastidial glucan phosphorylase 1 (PHS1) (dpe2/phs1). The additional elimination of phosphoglucan water dikinase (PWD), starch excess 4 (SEX4), isoamylase 3 (ISA3), and disproportionating enzyme 1 (DPE1) in the dpe2/phs1 mutant background demonstrates the alteration of starch granule number per chloroplast. This study provides insights into the control mechanism of granule number regulation in the chloroplast. The research regarding the sink tissue will emphasize the relationship between starch metabolism and the lipid metabolism pathway in oil palm fruits. This study was conducted to observe the alteration of starch parameters, metabolite abundance, and gene expression during oil palm fruit development with different oil yields. This study shows that starch and sucrose can be used as biomarkers for oil yield in oil palms. In addition, it is revealed that the enzyme isoforms related to starch metabolism influence the oil production in oil palm fruit. Overall, this thesis presents novel information regarding starch metabolism in the source tissue of A.thaliana and the sink tissue of E.guineensis. The results shown in this thesis can be applied to many applications, such as modifying the starch parameter in other plants for specific needs.}, language = {en} } @phdthesis{Dixit2023, author = {Dixit, Sneha}, title = {Tension-induced conformational changes of the Piezo protein-membrane nano-dome}, school = {Universit{\"a}t Potsdam}, pages = {94}, year = {2023}, abstract = {Mechanosensation is a fundamental biological process that provides the basis for sensing touch and pain as well as for hearing and proprioception. A special class of ion-channel proteins known as mechanosensitive proteins convert the mechanical stimuli into electrochemical signals to mediate this process. Mechanosensitive proteins undergo conformational changes in response to mechanical force, which eventually leads to the opening of the proteins' ion channel. Mammalian mechanosensitive proteins remained a long sought-after mystery until 2010 when a family of two proteins - Piezo1 and Piezo2 - was identifed as mechanosensors [1]. The cryo-EM structures of Piezo1 and Piezo2 protein were resolved in the last years and reveal a propeller-shaped homotrimer with 114 transmembrane helices [2, 3, 4, 5]. The protein structures are curved and have been suggested to deform the surrounding membrane into a nano-dome, which mechanically responds to membrane tension resulting from external forces [2]. In this thesis, the conformations of membrane-embedded Piezo1 and Piezo2 proteins and their tension-induced conformational changes are investigated using molecular dynamics simulations. Our coarse-grained molecular dynamics simulations show that the Piezo proteins induce curvature in the surrounding membrane and form a stable protein-membrane nano-dome in the tensionless membrane. These membrane-embedded Piezo proteins, however, adopt substantially less curved conformations in our simulations compared to the cryo-EM structures solved in detergent micelles, which agrees with recent experimental investigations of the overall Piezo nano-dome shape in membrane vesicles [6, 7, 8]. At high membrane tension, the Piezo proteins attain nearly planar conformations in our simulations. Our systematic investigation of Piezo proteins under different membrane tensions indicates a half-maximal conformational response at membrane tension values rather close to the experimentally suggested values of Piezo activation [9, 10]. In addition, our simulations indicate a widening of the Piezo1 ion channel at high membrane tension, which agrees with the channel widening observed in recent nearly flattened cryo-EM structures of Piezo1 in small membrane vesicles [11]. In contrast, the Piezo2 ion channel does not respond to membrane tension in our simulations. These different responses of the Piezo1 and Piezo2 ion channels in our simulations are in line with patch-clamp experiments, in which Piezo1, but not Piezo2, was shown to be activated by membrane tension alone [12].}, language = {en} } @phdthesis{HashemiRanjbar2023, author = {Hashemi Ranjbar, Seirana}, title = {Plasticity and trade-offs in plant metabolic networks}, school = {Universit{\"a}t Potsdam}, pages = {112}, year = {2023}, abstract = {A biological trade-off situation denotes the dependence between traits whereby an increase in the value of one of the traits leads to a decrease in the value of at least one of the others. Understanding trade-offs in cellular systems is relevant to understanding the limits and constraints to tuning desired phenotypes. Therefore, it is mainly the case for rates (i.e. fluxes) of biochemical reactions that shape not only molecular traits, like metabolite concentrations but also determine physiological traits, like growth. Intracellular fluxes are the final phenotype from transcriptional and (post)translational regulation. Quantifying intracellular fluxes provides insights into cellular physiology under particular growth conditions and can be used to characterize the metabolic activity of different pathways. However, estimating fluxes from labelling experiments is labour-intensive; therefore, developing approaches to accurately and precisely predict intracellular fluxes is essential. This thesis addresses two main problems: (i) identifying flux trade-offs and (ii) predicting accurate and precise reaction flux at a genome-scale level. To this end, the concept of an absolute flux trade-off is defined, and a constraint-based approach, termed FluTO, was developed to identify absolute flux trade-offs. FluTO is cast as a mixed integer programming approach applied to genome-scale metabolic models of E. coli, S. cerevisiae, and A. thaliana, imposing realistic constraints on growth and nutrient uptake.. The findings showed that trade-offs are not only species-specific but also specific to carbon sources. In addition, we found that different models of a single species have a different number of reactions in trade-offs. We also showed that absolute flux trade-offs depend on the biomass reaction used to model the growth of A. thaliana under different carbon and nitrogen conditions. Findings reflect the strong relation between nitrogen, carbon, and sulphur metabolisms in the leaves of C3 plants. The concept of relative trade-offs was introduced to further study trade-offs in metabolic networks. A constraint-based approach, FluTOr, was proposed to identify reactions whose fluxes are in relative trade-off concerning an optimized fitness-related cellular task, like growth. FluTOr was employed to find the relative flux trade-offsin the genome-scale metabolic networks of E. coli, S. cerevisiae, and A. thaliana. The results showed that in contrast to the A. thaliana model, the relative trade-offs in the two microorganisms depend on the carbon source, reflecting the differences in the underlying metabolic network. Furthermore, applying FluTOr also showed that reactions that participated in relative trade-offs were implicated in cofactor biosynthesis in the two microorganisms. Prediction of reaction fluxes in the constraint-based metabolic framework is usually performed by parsimonious flux balance analysis (pFBA), employing the principle of efficient usage of protein resources. However, we argued that principles related to the coordination of flux values, neglected in previous studies, provide other means to predict intracellular fluxes. To this end, we designed a constraint-based approach, termed complex-balanced FBA (cbFBA), to predict steady-state flux distributions that maximize the number of balanced complexes in a flux distribution, whereby multi-reaction dependencies are maximized. The comparative analysis showed a better agreement of the flux distributions resulting from cbFBA compared to pFBA with experimentally measured fluxes from 17 E. coli strains and 26 S. cerevisiae knock-out mutants. The results also showed that the predictions from cbFBA are more precise than those from pFBA since cbFBA results in a smaller space of alternative solutions than pFBA.}, language = {en} } @phdthesis{Shen2022, author = {Shen, Yawen}, title = {Functional characterization of the gene regulatory network of C2H2-type zine finger protein ZAT8 in Arabidopsis thaliana}, pages = {124}, year = {2022}, language = {en} } @phdthesis{Rolo2023, author = {Rolo, David}, title = {Assembly of photosystem I in thylakoid membranes}, school = {Universit{\"a}t Potsdam}, pages = {177}, year = {2023}, abstract = {The light reactions of photosynthesis are carried out by a series of multiprotein complexes embedded in thylakoid membranes. Among them, photosystem I (PSI), acting as plastocyanin-ferderoxin oxidoreductase, catalyzes the final reaction. Together with light-harvesting antenna I, PSI forms a high-molecular-weight supercomplex of ~600 kDa, consisting of eighteen subunits and nearly two hundred co-factors. Assembly of the various components into a functional thylakoid membrane complex requires precise coordination, which is provided by the assembly machinery. Although this includes a small number of proteins (PSI assembly factors) that have been shown to play a role in the formation of PSI, the process as a whole, as well as the intricacy of its members, remains largely unexplored. In the present work, two approaches were used to find candidate PSI assembly factors. First, EnsembleNet was used to select proteins thought to be functionally related to known PSI assembly factors in Arabidopsis thaliana (approach I), and second, co-immunoprecipitation (Co-IP) of tagged PSI assembly factors in Nicotiana tabacum was performed (approach II). Here, the novel PSI assembly factors designated CO-EXPRESSED WITH PSI ASSEMBLY 1 (CEPA1) and Ycf4-INTERACTING PROTEIN 1 (Y4IP1) were identified. A. thaliana null mutants for CEPA1 and Y4IP1 showed a growth phenotype and pale leaves compared with the wild type. Biophysical experiments using pulse amplitude modulation (PAM) revealed insufficient electron transport on the PSII acceptor side. Biochemical analyses revealed that both CEPA1 and Y4IP1 are specifically involved in PSI accumulation in A. thaliana at the post-translational level but are not essential. Consistent with their roles as factors in the assembly of a thylakoid membrane protein complex, the two proteins localize to thylakoid membranes. Remarkably, cepa1 y4ip1 double mutants exhibited lethal phenotypes in early developmental stages under photoautotrophic growth. Finally, co-IP and native gel experiments supported a possible role for CEPA1 and Y4IP1 in mediating PSI assembly in conjunction with other PSI assembly factors (e.g., PPD1- and PSA3-CEPA1 and Ycf4-Y4IP1). The fact that CEPA1 and Y4IP1 are found exclusively in green algae and higher plants suggests eukaryote-specific functions. Although the specific mechanisms need further investigation, CEPA1 and Y4IP1 are two novel assembly factors that contribute to PSI formation.}, language = {en} } @phdthesis{vonRebay2023, author = {von Rebay, Anna}, title = {The Designation of Marine Protected Areas}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-29174-6}, doi = {10.1007/978-3-031-29175-3}, pages = {XV, 278}, year = {2023}, abstract = {This book provides empirical evidence that all States have a universally binding obligation to adopt national laws and international treaties to protect the marine environment, including the designation of Marine Protected Areas. Chapter by chapter this obligation is detailed, providing the foundation for holding States responsible for fulfilling this obligation. The fundamentals are analysed in a preliminary chapter, which examines the legally binding sources of the Law of the Sea as well as its historical development to help readers understand the key principles at hand. The Law of the Sea provides more than 1000 instruments and more than 300 regulations concerning marine protection. While the scope of most treaties is limited either regarding species, regions or activities, one regulation addresses States in all waters: the obligation to protect and preserve the marine environment as stipulated under Art. 192 of the 1982 United Nations Convention on the Law of the Sea (UNCLOS). As this 'Constitution of the Ocean' not only contains conventional laws but also very broadly reflects pre-existing rules of customary international law, an extensive analysis of all statements made by States in the UN General Assembly, their practices, national laws and regulations as well as other public testimonials demonstrates that Art. 192 UNCLOS indeed binds the whole community of States as a rule of customary international law with an erga omnes effect. Due to the lack of any objections and its fundamental value for humankind, this regulation can also be considered a new peremptory norm of international law (ius cogens). While the sovereign equality of States recognises States' freedom to decide if and how to enter into a given obligation, States can also waive this freedom. If States accepted a legally binding obligation, they are thus bound to it. Concerning the specific content of Art. 192 UNCLOS, a methodical interpretation concludes that only the adoption of legislative measures (national laws and international agreements) suffices to comply with the obligation to protect and preserve the marine environment, which is confirmed by the States' practices and relevant jurisprudence. When applied to a specific geographical area, legislative measures to protect the marine environment concur with the definition of Marine Protected Areas. Nonetheless, as the obligation applies to all waters, the Grotian principle of the freedom of the sea dictates that the restriction of activities through the designation of Marine Protected Areas, on the one hand, must be weighed against the freedoms of other States on the other. To anticipate the result: while all other rights under the UNCLOS are subject to and contingent on other regulations of the UNCLOS and international law, only the obligation to protect and preserve the marine environment is granted absolutely - and thus outweighs all other interests}, language = {en} } @phdthesis{Kontbay2022, author = {Kontbay, K{\"u}bra}, title = {Nin-Like Protein (NLP) transcription factors}, pages = {113}, year = {2022}, language = {en} } @phdthesis{Akbal2023, author = {Akbal, Zeynep}, title = {Lived-Body Experiences in Virtual Reality}, series = {Digitale Gesellschaft}, volume = {61}, journal = {Digitale Gesellschaft}, publisher = {transcript}, address = {Bielefeld}, isbn = {978-3-8376-6676-2}, school = {Universit{\"a}t Potsdam}, pages = {210}, year = {2023}, language = {en} } @phdthesis{Ribacki2023, author = {Ribacki, Enrico}, title = {Intra-granitic pegmatites of the Las Chacras-Potrerillos batholith, Argentina}, school = {Universit{\"a}t Potsdam}, pages = {XVIII, 183}, year = {2023}, language = {en} } @phdthesis{John2023, author = {John, Sheeba}, title = {Characterizing the role of Heat Shock Factor HSFA 7b in regulating thermomemory at the SAM in Arabidopsis thaliana}, school = {Universit{\"a}t Potsdam}, pages = {122}, year = {2023}, abstract = {Heat stress (HS) is one of the major abiotic stresses which adversely affects the survival and growth of plants due to their sessile nature. To combat the detrimental effects of HS and develop thermotolerance, plants have evolved several defense mechanisms. Thermomemory is one such molecular mechanism whereby plants that have been acclimated (or primed/P) by a moderate HS can respond more efficiently and continue their growth after exposure to a severe or lethal HS (called triggering/T), while unprimed plants cannot survive. Thermomemory is known to be regulated by several transcription factors (TFs), epigenetic changes, chromatin remodellers, post-transcriptional changes and it also involves protein stability control and primary metabolism adjustment. Recent research has suggested that the shoot apical meristem (SAM) in Arabidopsis thaliana has a distinct transcriptional thermomemory which is possibly regulated by eight TFs called HEAT SHOCK FACTORS (HSFs). The main objective of this PhD thesis is to investigate the role of HSFA7b (one of the eight HSFs), in regulating thermomemory at the SAM by identifying the molecular networks it regulates. HSFA7a, a close homolog of HSFA7b, is also one of the eight HSFs that are involved in regulating thermomemory at the SAM. Thermomemory was found to be defective in the hsfa7b and hsfa7a hsfa7b mutants; the percentage survival of these seedlings was significantly lower than in wild-type (WT) seedlings after the priming and triggering (PT) treatment. Transcriptome and ChIP analyses were performed to identify the molecular networks controlled by HSFA7b and its close homolog HSFA7a, in regulating thermomemory at the SAM. The chromatin regulator SPLAYED (SYD) was found to be regulated by both HSFA7a and HSFA7b at the SAM during thermomemory. SYD is directly involved in SAM maintenance by directly regulating WUSCHEL (WUS), a master regulator of stem cell maintenance. WUS expression was down-regulated at the SAM of PT treated hsfa7a/b mutants compared to WT-Col-0 seedlings. HSFA7a and HSFA7b also jointly regulate the expression of orphan gene QUA QUINE STARCH (QQS) during thermomemory. Starch accumulation negatively correlates with QQS expression and this trend was observed in WT plants in response to thermopriming. The remobilization of starch was affected in the hsfa7a/b mutants compared to WT plants during the recovery period after T treatment. These findings indicate that defects in SAM maintenance and starch remobilization could possibly contribute to the reduced thermomemory in the hsfa7a/b mutants. Moreover, transcriptome and ChIP analysis indicate that ethylene signaling genes are directly regulated by HSFA7b during thermomemory. Transcriptome analysis of the HSFA7b-IOE line indicates that HSFA7b positively regulates the expression of HEAT STRESS ASSOCIATED 32 (HSA32), an important thermomemory gene, and HSFA7b strongly suppresses the expression of the reactive oxygen species (ROS) responsive REDOX RESPONSIVE TRANSCRIPTION FACTOR 1 (RRTF1) gene, which is also a repressed target of SYD. In Arabidopsis, the HSFA7b transcript undergoes alternative splicing at high temperatures to form two splice variants: one correctly/constitutively spliced variant which is functional and codes for the HSFA7b protein and one intron retained splice variant. Higher accumulation of the functional HSFA7b splice variant was found at the SAM compared to other tissues. Moreover, accumulation of the functional splice variant was higher in P and PT plants compared to control plants, whereas higher levels of the intron retained splice variant is found in plants subjected directly to the T treatment. The intron retained HSFA7b splice variant is degraded by the non-sense mediated decay (NMD) pathway as a means of regulating transcript level essential for protein synthesis at high temperatures. Importantly, HSFA7b protein accumulation was observed in plants subjected to PT treatment that survive and continue growth, but not in plants subjected directly to T treatment that do not survive, indicating that constitutive/ correct splicing of the HSFA7b transcript is a component of thermomemory. Taken together, these findings suggest that HSFA7a and HSFA7b jointly regulate SAM maintenance via the chromatin remodeller SYD and starch remobilization via QQS. In addition to them, HSFA7b also regulates the expression of ethylene signaling genes, heat responsive genes and the ROS responsive RRTF1. Furthermore, constitutive/correct splicing in the HSFA7b transcript is also an essential component of thermomemory.}, language = {en} } @phdthesis{vonBismarck2023, author = {von Bismarck, Thekla}, title = {The influence of long-term light acclimation on photosynthesis in dynamic light}, school = {Universit{\"a}t Potsdam}, pages = {x, 163}, year = {2023}, abstract = {Photosynthesis converts light into metabolic energy which fuels plant growth. In nature, many factors influence light availability for photosynthesis on different time scales, from shading by leaves within seconds up to seasonal changes over months. Variability of light energy supply for photosynthesis can limit a plant´s biomass accumulation. Plants have evolved multiple strategies to cope with strongly fluctuation light (FL). These range from long-term optimization of leaf morphology and physiology and levels of pigments and proteins in a process called light acclimation, to rapid changes in protein activity within seconds. Therefore, uncovering how plants deal with FL on different time scales may provide key ideas for improving crop yield. Photosynthesis is not an isolated process but tightly integrates with metabolism through mutual regulatory interactions. We thus require mechanistic understanding of how long-term light acclimation shapes both, dynamic photosynthesis and its interactions with downstream metabolism. To approach this, we analyzed the influence of growth light on i) the function of known rapid photosynthesis regulators KEA3 and VCCN1 in dynamic photosynthesis (Chapter 2-3) and ii) the interconnection of photosynthesis with photorespiration (PR; Chapter 4). We approached topic (i) by quantifying the effect of different growth light regimes on photosynthesis and photoprotection by using kea3 and vccn1 mutants. Firstly, we found that, besides photosynthetic capacity, the activities of VCCN1 and KEA3 during a sudden high light phase also correlated with growth light intensity. This finding suggests regulation of both proteins by the capacity of downstream metabolism. Secondly, we showed that KEA3 accelerated photoprotective non-photochemical quenching (NPQ) kinetics in two ways: Directly via downregulating the lumen proton concentration and thereby de-activating pH-dependent NPQ, and indirectly via suppressing accumulation of the photoprotective pigment zeaxanthin. For topic (ii), we analyzed the role of PR, a process which recycles a toxic byproduct of the carbon fixation reactions, in metabolic flexibility in a dynamically changing light environment. For this we employed the mutants hpr1 and ggt1 with a partial block in PR. We characterized the function of PR during light acclimation by tracking molecular and physiological changes of the two mutants. Our data, in contrast to previous reports, disprove a generally stronger physiological relevance of PR under dynamic light conditions. Additionally, the two different mutants showed pronounced and distinct metabolic changes during acclimation to a condition inducing higher photosynthetic activity. This underlines that PR cannot be regarded purely as a cyclic detoxification pathway for 2PG. Instead, PR is highly interconnected with plant metabolism, with GGT1 and HPR1 representing distinct metabolic modulators. In summary, the presented work provides further insight into how energetic and metabolic flexibility is ensured by short-term regulators and PR during long-term light acclimation.}, language = {en} } @phdthesis{Rasul2023, author = {Rasul, Fiaz}, title = {Biostimulant SuperFifty based molecular priming to increase plant strength and stress tolerance}, year = {2023}, language = {en} } @phdthesis{Zakrzewski2023, author = {Zakrzewski, Tanja}, title = {Identity and violence in early modern Granada}, series = {Lexington studies in modern Jewish history, historiography, and memory}, journal = {Lexington studies in modern Jewish history, historiography, and memory}, publisher = {Lexington Books}, address = {Lanham}, isbn = {978-1-66691-534-1}, school = {Universit{\"a}t Potsdam}, pages = {VII, 245}, year = {2023}, language = {en} } @phdthesis{Teitscheid2023, author = {Teitscheid, Jana}, title = {Information and communication technologies usage and the effects on the human mind}, school = {Universit{\"a}t Potsdam}, pages = {XII, 228}, year = {2023}, abstract = {The digitization has permeated almost all aspects of an individual's life. In the work context as well as in the private sphere, one readily encounters and relies on Information and Communication Technologies (ICTs), such as Social Networking Sites (SNS), smartphones and so forth. By communicating with as well as obtaining information via such technologies, ICTs engage one's mind as interaction happens. This interaction of ICTs and the human mind form the focal topic of this thesis. Within this thesis, the human mind is represented on behalf of a facilitated model comprising a perceptual, a cognitive and a motor subsystem. ICTs represent an external stimulus, which triggers the human mind's perceptual subsystem, the cognitive subsystem and eventually leads to a motoric response via the motor subsystem. The external stimulus causing this event chain is within this thesis an ICT. The digital environment and related ICTs are high attention environments offering large and easily accessible amounts of information. Not surprisingly, issues may arise, when the human mind deals with ICTs. Thus, the interplay between ICTs and the human mind entails downsides. This thesis investigates these downsides and in addition the ICT-based factors that cause these downsides. More specifically, the thesis investigates these two aspects as research questions in the context of SNSs as well as other ICTs (such as smartphones, e-learning etc.). Addressing the research questions, 8 articles are submitted within this thesis which address the topic with different methodologies, including quantitative, qualitative, mixed methods as well as systematic literature reviews. Article 1 investigates factors that lead to SNS fatigue and discontinuance intentions in a mixed-methods design. Article 2 explores if certain factors encountered on a newsfeed hamper sensemaking. Article 3 proposes a study design to explore the link between disorderly perceptions of a SNSs newsfeed and gender stereotype activations. Article 4 considers the interplay between users and algorithms via the newsfeed interface and the implications for relevance perceptions. Article 5 explores information acquisition, hampering factors and verification strategies of social media users. Article 6 systematically reviews addiction scales of various ICTs. Article 7 investigates click behavior in e-learning contexts and how this is linked to cultural and personality traits. Finally, article 8 offers a comprehensive overview of the antecedents and consequences of children's smartphone usage. Within the specific context of SNSs, the thesis suggests that the cognitive tolls imposed on users' minds cause adverse effects, such as impaired sensemaking, fatigue, stereotype activation as well as intentions to discontinue the service. Other ICTs lead to addiction, and i.e., smartphones evidence to cause cognitive impairments in children. Factors on the ICT side that promote these adverse effects are linked to specific features, such as the newsfeed for SNSs and entail overload or perceptions of disorder. The thesis adds theoretically to the understanding of downsides that arise from the interplay between human minds and ICTs. Especially, the context of SNSs is spotlighted and insights add to the growing body of literature on experiences and perceptions. For instance, one study's result suggests that considering information organization is as important as merely decreasing overload perceptions from the users in countering adverse effects of SNS usage. Practically, the thesis emphasizes the importance of mindful interaction with ICTs. Future research is welcome to build on the exploratory investigations and may draw an even more holistic picture to enhance the interaction between ICTs and the human mind.}, language = {en} } @phdthesis{Gramma2023, author = {Gramma, Vladislav}, title = {Potato FLC-like and SVP-like proteins jointly control growth and distinct developmental processes}, school = {Universit{\"a}t Potsdam}, pages = {x, 138}, year = {2023}, abstract = {Based on worldwide consumption, Solanum tuberosum L. (potato) is the most important non-grain food crop. Potato has two ways of stable propagation: sexually via flowering and vegetatively via tuberization. Remarkably, these two developmental processes are controlled by similar molecular regulators and mechanisms. Given that FLC and SVP genes act as key flowering regulators in the model species Arabidopsis and in various other crop species, this study aimed at identifying FLC and SVP homologs in potato and investigating their roles in the regulation of plant development, with a particular focus on flowering and tuberization. Our analysis demonstrated that there are five FLC-like and three SVP like proteins encoded in the potato genome. The expression profiles of StFLCs and StSVPs throughout potato development and the detected interactions between their proteins indicate tissue specificity of the individual genes and distinct roles of a variety of putative protein complexes. In particular, we discovered that StFLC-D, as well as StFLC-B, StSVP-A, and StSVP-B play a complex role in the regulation of flowering time, as not only increased but also decreased levels of their transcripts promote earlier flowering. Most importantly, StFLC-D has a marked impact on tuberization under non-inductive conditions and susceptibility to temperature-induced tuber malformation, also known as second growth. Plants with decreased levels of StFLC-D demonstrated a strong ability to produce tubers under long days and appeared to be insensitive to temperature-induced second growth. Lastly, our data also suggests that StFLCs and StSVPs may be involved in the nitrogen-dependent regulation of potato development. Taken together, this study highlights the functional importance of StFLC and StSVP genes in the regulation of distinct developmental processes in potato.}, language = {en} } @phdthesis{Stork2023, author = {Stork, Carsten}, title = {Organizational negotiation mnagement}, series = {Schriftenreihe zum Verhandlungsmanagement ; 23}, journal = {Schriftenreihe zum Verhandlungsmanagement ; 23}, publisher = {Kovac}, address = {Hamburg}, isbn = {978-3-339-13554-4}, issn = {2365-7898}, pages = {XVII, 168}, year = {2023}, abstract = {Negotiations are a way of joint decision-making and thereby a form of social conflict. By determining the concrete allocation of scarce resources, negotiations have a great impact on the value creation of companies. If companies succeed in achieving better negotiation results in the long term, they can increase their profitability. Ensuring a company's negotiation success is therefore an organizational issue of central importance. While the question of ensuring individual negotiation success has been the subject and topic of multidisciplinary research for a long time, the question of how organizations can implement and ensure continuous negotiation success remains largely unexplored. This dissertation therefore aims to investigate how companies enable their employees to consistently achieve better negotiation outcomes. It is significant that, in the corporate context, negotiators do not act as individuals but as embedded representatives of an organization, and that negotiations are not one-time events but recurring necessities for the existence of the organization instead. In organizations, those recurring processes with a similar fundamental structure are handled by routines. A planned improvement of routines is often forced by new artifacts. In this context, artifacts refer to human-created technologies with which humans interact within routines and therefore artifacts have a central influence on executing the routine. If negotiation activities in companies are represented by organizational routines, one central issue for improving companies' negotiation performance is the artifacts' incorporation into organizational negotiation routines that facilitate the efficient application of the insights from negotiation research. The dissertation consists of three studies that were written as research papers to examine artifacts in the organizational negotiation context. The first study focuses on the pre-negotiation stage and presents four tools to assist negotiation practitioners in efficiently preparing for negotiation. The study examines the negotiation preparation's effectiveness and efficiency and the negotiation outcome in a case-based experiment. The second study is devoted to a closer examination of the barriers that inhibit the adoption of negotiation support systems (NSSs) as one kind of organizational negotiation artifact. The investigation is conducted using a structural equation model based on information from participating practitioners. The third study is concerned with the future of negotiation support system research. An exploratory study based on qualitative in-depth interviews with proven and published experts in the field aims to evaluate the current state of research. The general discussion of the dissertation connects, summarizes, and concludes the study results and derives implications for practice, limitations, and future research ideas.}, language = {en} } @phdthesis{Frank2023, author = {Frank, Bradley D.}, title = {Complex and adaptive soft colloids}, school = {Universit{\"a}t Potsdam}, pages = {XIV, 154}, year = {2023}, language = {en} } @phdthesis{Nikolova2023, author = {Nikolova, Mariya Dimitrova}, title = {How whiteness claimed the future}, series = {American Frictions}, volume = {7}, journal = {American Frictions}, publisher = {De Gruyter}, address = {Berlin}, isbn = {978-3-11-079999-6}, doi = {10.1515/9783110799996}, school = {Universit{\"a}t Potsdam}, pages = {178}, year = {2023}, abstract = {Interested in the ideological workings of fiction, I study how major avant-garde tropes promote the potential of permanent renewal as white America's property. Renewal ties to the capacities to create, progress, transcend, and simply be. From Black critique we know that, within dominant discourse, all these capacities have been denied to Black bodies ever since colonization. Black work has been fetishized, appropriated, stolen, and dismissed in and by dominant culture, while Black being is construed as negativity and barred on the level of ontology. It follows then that racialization operates on multiple levels in the conceptual frame of renewal. I study this conceptualization by re-reading the works of and criticism on progressive white authors. I examine how images of renewal enable the claim on futurity, transformative potential, and movement forward as exclusively white properties. Premised on oppositions between positive capacities and a state of complete incapacitation, these images are often viewed as separate constructions. This project shows that, deriving from white ideology, such representations are symbiotic and simultaneous - the "good" story of white renewal rests on the continual transgression towards Black being.}, language = {en} } @phdthesis{Leer2023, author = {Leer, Marina}, title = {Computational analysis of the effects of ageing and diet on stem cell function and ectopic fat accumulation in the musculoskeletal system}, school = {Universit{\"a}t Potsdam}, pages = {130}, year = {2023}, abstract = {The musculoskeletal system provides support and enables movement to the body, and its deterioration is a crucial aspect of age-related functional decline. Mesenchymal stromal cells (MSCs) play an important role in musculoskeletal homeostasis due to their broad differentiation potentials and their ability to support osteogenic and myogenic tissue maintenance and regeneration. In the bone, MSCs differentiate either into osteochondrogenic progenitors to form osteocytes and chondrocytes, or increasingly with age into adipogenic progenitors which give rise to bone-resident adipocytes. In skeletal muscle, during healthy regeneration MSCs provide regulatory signals that activate local, tissue-specific stem cells, known as satellite cells, which regenerate contractile myofibres. This process involves a significant cross-talk to immune cells stemming from both lymphoid and myeloid lineages. During ageing, muscle-resident MSCs undergo increased adipogenic lineage commitment, causing niche changes that contribute to fatty infiltration in muscles. These shifts in cell populations in bone lead to the loss of osteogenic cells and subsequently osteoporosis, or in muscle to impaired regeneration and to the development of sarcopenia. However, the signals that drive transition of MSCs into their respective cellular fates remain elusive. This thesis aims to elucidate the transcriptional shifts modulating cell states and cell types in musculoskeletal MSC fate determination. Single-cell RNA-sequencing (scRNA-seq) was used to characterise cell type-specific transcript regulation. State-of-the-art bioinformatics tools were combined with different analytical platforms that include both droplet-based scRNA-seq for large heterogeneous populations, and microfluidics-based scRNA-seq to assess small, rare subpopulations. For each platform, distinct computational pipelines were established including filtering steps to exclude low-quality cells, and data visualisation was performed by dimensionality reduction. Downstream analysis included clustering, cell type annotation, and differential gene expression to investigate transcriptional states in defined cell types during ageing and injury in the muscle and bone. Finally, a novel tool to assess publication activities in defined areas of research for the identified marker genes was developed. The results in the bone indicate that ageing MSCs increasingly commit towards an adipogenic fate at the expense of osteogenic specialisation. The data also suggests that significant cell population shifts of MSC-type fibro-adipogenic progenitors during muscle ageing underlie the pathologies observed in homeostatic and post-injury regenerative conditions. High-throughput visualisation of publication activity for candidate genes enabled more effective biological evaluation of scRNA-seq data. These results expose critical age-related changes in the stem cell niches of skeletal muscle and bone, highlight their respective sensitivity to nutrition and pathology, and elucidate novel factors that modulate stem cell-based regeneration. Targeting these processes might improve musculoskeletal health in the context of ageing and prevent the negative effects of pathological lineage determination.}, language = {en} } @phdthesis{Hettinger2023, author = {Hettinger, Katharina}, title = {Teaching-related self-efficacy beliefs of teachers}, school = {Universit{\"a}t Potsdam}, year = {2023}, abstract = {Teacher self-efficacy is highly relevant for effective teaching, student academic development, and teachers' wellbeing, as theoretical work (Bandura, 1997; Tschannen-Moran et al., 1998) and empirical studies (i.e., Burić \& Kim, 2020; Klassen \& Chiu, 2010; van Uden et al., 2013) have shown associations with effective classroom management, student support, student motivation, and teachers' job satisfaction. Given the importance of teacher self-efficacy for teaching and learning, it is interesting to note that existing research is limited in several aspects - first, longitudinal studies on the relations between teacher self-efficacy and student academic outcomes are widely missing; second, empirical studies often assess teacher self-efficacy as a one-dimensional construct, neglecting its multidimensional character; third, studies often only focus on either the students' or the teachers' perspective on teaching and thus do not include simultaneously multiple sources of information on teaching practices as a consequence of teacher self-efficacy; fourth, research often does not systematically consider the effects of teacher self-efficacy on students' academic outcomes at both the group and individual level. Against this backdrop, this dissertation presents three longitudinal studies that aim to contribute to a more detailed perspective on teacher self-efficacy by examining systematically and longitudinally the relations between multiple dimensions of teacher self-efficacy and theoretically aligned teaching quality facets as perceived by teachers and students, as well as their relations to students' motivational-affective outcomes - more concretely, their relations to students' interest, enjoyment, and self-efficacy in a multi-level analysis approach. Study 1 examines the longitudinal relations between teacher self-efficacy for classroom management and student-perceived monitoring and social relatedness, and investigates whether the two student-reported teaching dimensions explain the relations between teacher self-efficacy for classroom management and student enjoyment using multi-level analyses. Study 2 examines longitudinally how teacher self-efficacy for student engagement relates to student interest through student- and teacher-perceived emotional support. Also, including student and teacher perspectives on teaching, Study 3 examines the longitudinal relations between specific facets of teacher self-efficacy for classroom management and classroom discipline, teacher self-efficacy for instructional strategies and cognitive activation, teacher self-efficacy for student engagement and competence support, teacher self-efficacy for emotional support and social relatedness, as well as teacher self-efficacy for student-oriented teaching and learning goal-oriented instruction with students' enjoyment and self-efficacy. Furthermore, in Studies 2 and 3 the cross-level mediation effects of longitudinal relations with teacher self-efficacy on student motivational-affective characteristics via teaching practices are examined in order to address the lack of empirical studies disentangling the relations for specifically individual- vs. group-level effects. The limitations and implications are discussed in terms of their theoretical and practical relevance for school practice, teacher education, and teacher training.}, language = {en} } @phdthesis{Buehler2023, author = {B{\"u}hler, Miriam}, title = {The role of (xeno)hormone-activated GPER1 for centrosome amplification and whole chromosomal instability in colon cell lines}, school = {Universit{\"a}t Potsdam}, pages = {IX, 144}, year = {2023}, abstract = {The G protein-coupled estrogen receptor (GPER1) is acknowledged as an important mediator of estrogen signaling. Given the ubiquitous expression of GPER1, it is likely that the receptor plays a role in a variety of malignancies, not only in the classic hormonally regulated tissues (e.g., breast, ovary, and prostate), but also in the colon. As colorectal cancer (CRC) is the third most common cancer in both men and women worldwide and environmental factors and dietary habits are important risk factors, it is increasingly recognized that natural and synthetic hormones and their associated receptors might play a role in CRC. Through oral consumption, environmental contaminants with endocrine activity are in contact with the gastrointestinal mucosa, where they might exert their toxic effects. Although GPER1 has been shown to be engaged in physiological and pathophysiological processes, its role in CRC remains poorly understood. Thus, pro- as well as anti-tumorigenic effects are described in the literature. This thesis has uncovered novel roles of GPER1 in mediating major CRC-associated phenotypes in transformed and non-transformed colon cell lines. Exposure to the estrogens 17β-estradiol (E2), bisphenol-A (BPA) and diethylstilbestrol (DES) but also the androgen dihydrotestosterone (DHT) resulted in GPER1-dependent induction of supernumerary centrosomes, whole chromosomal instability (w-CIN) and aneuploidy. Indeed, both knockdown and inhibition of GPER1 attenuated the generation of (xeno)hormone-driven supernumerary centrosomes and karyotype instability. Mechanistically, (xeno)hormone-induced centrosome amplification was associated with transient multipolar mitosis and the generation of so called anaphase "lagging" chromosomes. The results of this thesis propose a GPER1/PKA/AKAP9-pathway in regulating centrosome numbers in colorectal cancer cells and the involvement of the centriolar protein centrin. Remarkably, exposure to (xeno)hormones resulted in atypical enlargement and unexpected phosphorylation of the centriole marker centrin in interphase. These findings provide a novel role for GPER1 in key CRC-prone lesions and shed light on underlying mechanisms that involve GPER1 function in the colon. Elucidating to what extent centrosomal proteins are involved in the GPER1-mediated aneugenic effect will be an important task for future studies. The present study was intended to lay a first foundation to understand the molecular basis and potential risk factors of CRC which might help to reduce the use of laboratory animals. Since numerous animal experiments are conducted in biomedical research, the development of alternative methods is indispensable. The Federal Institute for Risk Assessment (BfR) as the German Center for the Protection of Laboratory Animals (Bf3R) addresses this issue by uncovering underlying mechanisms leading to colorectal cancer as necessary prerequisite in order to develop alternative methods.}, language = {en} } @phdthesis{Jiang2023, author = {Jiang, Li}, title = {Analysis of the role of Heat shock factors and Mediator subunits in heat stress memory in Arabidopsis thaliana}, school = {Universit{\"a}t Potsdam}, pages = {194}, year = {2023}, abstract = {In nature, plants often encounter biotic and abiotic stresses, which can cause reduced crop yield and quality, and threaten the nutrition of a growing human population. As heat stress (HS) is one of the main abiotic stresses, and is projected to increase due to global warming, it is necessary to better understand how plants respond and survive under HS. In Arabidopsis thaliana, plants can survive under severe HS if primed by a non-lethal HS, a process called acquisition of thermotolerance. This primed stated can be maintained for several days, and the ability of plants to maintain the primed state is called maintenance of acquired thermotolerance (mATT) or HS memory. According to current research, two Heat shock factors (HSFs) HSFA2 and HSFA3 are known to account for the majority of mATT capability, and there are other HSFs e.g. HSFA1b and HSFA6b in HSF complexes containing HSFA2 and/or HSFA3, however, the roles of these HSFs in HS memory is not clearly understood. Moreover, the mechanism of these HSFs in regulating HS memory is unclear, whether transcriptional machinery e.g. the Mediator complex contributes to transcriptional memory. This work investigates the role of HSFs and Mediator subunits in HS memory in A. thaliana. For the role of HSFs, the interaction between HSFA1b and HSFA2 during HS memory phase was confirmed by in vivo co- immunoprecipitation (Co-IP). HSFA1b, HSFA2, HSFA3 and HSFA6b targeted HS memory-related genes according to DNA affinity purification sequencing (DAP-seq) data, and targets of HSFA1b were confirmed in vivo by chromatin immunoprecipitation qPCR (ChIP-qPCR). The mutant of hsfa6b showed an HS memory deficiency phenotype in mATT survival assay. These data confirmed the role for HSFA2 and HSFA3 in HS memory, and suggest that HSFA1b and HSFA6b also function in HS memory. The Mediator complex functions as an RNA Polymerase II (RNA Pol II) co-regulator, and includes Head, Middle, Tail and Kinase modules. Both MED23 and MED32 belong to the Tail module, and they have a positive role in HS memory. MED23 interacted with HSFA3, as determined by yeast two hybrid (Y2H) and in vivo Co-IP assays. The med23 mutant showed a decreased HS memory phenotype, reduced expression of Type I (sustained expression) memory genes following HS, and reduced accumulation of the memory-associated Tri-methylation of histone H3 lysine 4 (H3K4me3)histone modification at HS memory-related gene loci after HS. MED23 was recruited to HS-inducible memory and non-memory genes after HS, as determined by ChIP-qPCR. The med32 mutant showed a reduced HS memory phenotype, decreased expression of Type I and Type II (hyper-induction) memory genes, and lower accumulation of H3K4me3 at memory gene lociafter HS. However, MED32 did not show interaction with any tested HSF in Y2H or in vivo Co-IP. MED32 regulated the recruitment of RNA Pol II at HS-inducible genes after HS, but was not itself recruited to HS memory genes after HS. These results provided more evidence that the Mediator subunits MED23 and MED32 regulate HS memory on transcriptional and epigenetic levels. In general, this work provides a better insight into the molecular mechanism of how HSFs and Mediator subunits regulate HS memory in plants and will provide new perspectives to breed crops with improved thermotolerance.}, language = {en} } @phdthesis{Stoermann2023, author = {St{\"o}rmann, Florian Konstantin}, title = {Multifunctional Microballoons for the active and passive control of fluid-flows}, school = {Universit{\"a}t Potsdam}, pages = {XVI, 104, A24}, year = {2023}, abstract = {Functional materials, also called "Smart Materials", are described by their ability to fulfill a desired task through targeted interaction with its environment. Due to this functional integration, such materials are of increased interest, especially in areas where the increasing micronization of components is required. Modern manufacturing processes (e.g. microfluidics) and the availability of a wide variety of functional materials (e.g. shape memory materials) now enable the production of particle-based switching components. This category includes micropumps and microvalves, whose basic function is the active control of liquid flows. One approach in realizing those microcomponents as pursued by this work, enables variable size-switching of water-filled microballoons by implementing a stimulus-sensitive switching motif in the capsule's membrane shell, while being under the influence of a constant driving force. The switching motif with its gatekeeper function has a critical influence on one or more material parameters, which modulate the capsule's resistance against the driving force in microballoon expansion process. The advantage of this concept is that even non-variable analyte conditions, such as concentration levels of ions, can be capitalized to generate external force fields that, under the control of the membrane, cause an inflation of the microballoon by an osmotically driven water influx. In case of osmotic pressure gradients as the driving force for the capsule expansion, material parameters associated with the gatekeeper function are specifically the permeability and the mechanical stiffness of the shell material. While a modulation of the shell permeability could be utilized to kinetically impede the water influx on large time scales, a modulation of the shell's mechanical stiffness even might be utilized to completely prevent the capsule inflation due to a possible non-deformability beneath a certain threshold pressure. In polymer networks, which are a suitable material class for the demanded capsule shell because of their excellent elasticity, both the permeability and the mechanical properties are strongly influenced by the crystallinity of the material. Since the permeability is effectively reduced with increasing crystallinity, while the mechanical stiffness is simultaneously greatly increased, both effects point in the same direction in terms of their functional relationship. For this reason and due to a reversible and contactless modulation of the membrane crystallinity by heat input, crystallites may be suitable switching motifs for controlling the capsule expansion. As second design element of reversible expandable microballoons, the capsule geometry, defined by an aqueous core enveloped by the temperature-sensitive polymer network membrane, should allow an osmotic pressure gradient across the membrane layer. The strength of the inflation pressure and the associated inflation velocity upon membrane melting should be controlled by the salt concentration within the aqueous core, while a turn in the osmotic gradient should furthermore allow the reversible process of capsule deflation. Therefore, it should be possible to build either microvalves and micropumps, while their intended action of either pumping or valving is determined by their state of expansion and the direction of the osmotic pressure gradient.. Microballoons of approximately 300 µm in diameter were formed via droplet-based microfluidics from double-emulsion templates (w/o/w). The elastomeric capsule membrane was formed by photo-crosslinking of methacrylate (MA) functionalized oligo(ε-caprolactone) precursors (≈ 3.8 MA-arms, Mn ≈ 12000 g mol-1) within the organic medium layer (o) via UV-exposure after droplet-formation. After removal of the toluene/chloroform mixture by slow extraction via the continuous aqueous phase, the capsules solidified under the development of a characteristic "mushroom"-like shape at specific experimental conditions (e.g. λ = 308 nm, 57 mJ·s-1·cm-2, 16 min). It could be furthermore shown that in dependency to the process parameters: oligomer concentration and curing-time also spherical capsules were accessible. Long curing-times and high oligomer concentrations at a fixed light-intensity favored the formation of "mushroom"-like capsules, whereas the contrary led to spherical shaped capsules. A comparative study on thin polymer network films of same composition and equal treatment proved a correlation between the film's crosslink density and their contraction capability, while stronger crosslinked polymer networks showed a stronger contraction after solvent removal. In combination with observations during capsule solidification via light-microscopy, where a continuous shaping from almost spherical crosslinked templates to "mushroom"-shaped and solidified capsules was stated, the following mechanism was proposed. In case of low oligomer contents and short curing-times, the contraction of the capsule shell during solvent removal is strongly diminished due to a low degree of crosslinking. Therefore, the solidifying shell could freely collapse onto the aqueous core. In the other case, high oligomer concentrations and long curing-times will favor the formation of highly crosslinked capsule membranes with a strong contraction capability. Due to an observed decentered location of the aqueous core within the swollen polymer network, an uneven radial stress along the capsule's circumference is exerted to the incompressible core. This lead to an uneven contraction during solvent removal and a directed flow of the core fluid into the direction of the minimal stress vector. In consequence, the initially thicker spherical cap contracts, whereas the opposing thinner spherical cap get stretched. The "mushroom"-shape over some advantages over their spherical shaped counterparts, why they were selected for the further experiments. Besides the necessity of a high density of crosslinking for the purpose of extraordinary elasticity and toughness, the form-anisotropy promotes a faster microballoon expandability due to a partial reduction of the membrane thickness. Additionally, pre-stretched regions of thin thickness might provide a better resistance against inflation pressure than spherical but non-stretched capsules of equal membrane thickness. The resulting "mushroom"-shaped microcapsules exhibited a melting point of Tm ≈ 50 - 60 °C and a degree of crystallinity of Xc ≈ 29 - 38 \% depending on the membrane thickness and internal salt content, which is slightly lower than for the non-crosslinked oligomer and reasoned by a limited chain mobility upon crosslinking. Nonetheless, the melting transition of the polymer network was associated with a strong drop in its mechanical stiffness, which was shown to have a strong influence on the osmotic driven expansion of the microcapsules. Capsules that were subjected to osmotic pressures between 1.5 and 4.7 MPa did not expand if the temperature was well below the melting point of the capsule's membrane, i.e. at room temperature. In contrast, a continuous expansion, while approaching asymptotically to a final capsule size, was observed if the temperature exceeded the melting point, i.e. 60 °C. Microballoons, which were kept for 56 days at ∆Π = 1.5 MPa and room temperature, did not change significantly in diameter, why the impact of the mechanical stiffness on the expansion behavior is considered to be the greater than the influence of the shell permeability. The time-resolved expansion behavior of the microballoons above their Tm was subsequently modeled, using difusion equations that were corrected for shape anisotropy and elastic restoring forces. A shape-related and expansion dependent pre-factor was used to dynamically address the influence of the shell thickness differences along the circumference on the inflation velocity, whereas the microballoon's elastic contraction upon inflation was rendered by the inclusion of a hyperelastic constitutive model. An important finding resulting from this model was the pronounced increase in inflation velocity compared to hypothetical capsules with a homogeneous shell thickness, which stresses the benefit of employing shape anisotropic balloon-like capsules in this study. Furthermore, the model was able to predict the finite expandability on basis of entropy-elastic recovery forces and strain-hardening effects. A comparison of six different microballoons with different shell thicknesses and internal salt contents showed the linear relationship between the volumetric expansion, the shell thickness and the applied osmotic pressure, as represented by the model. As the proposed model facilitates the prediction of the expansion kinetics depending on the membranes mechanical and diffusional characteristics, it might be a screening tool for future material selections. In course of the microballoon expansion process, capsules of intermediate diameters could be isolated by recrystallization of the membrane, which is mainly caused by a restoration of the membrane's mechanical stiffness and is otherwise difficult to achieve with other stimuli-sensitive systems. The capsule's crystallinity of intermediate expansion states was nearly unchanged, whereas the lamellar crystal size tends to decreased with the expansion ratio. Therefore, it was assumed that the elastic modulus was only minimally altered and might increased due to the networks segment-chain extension. In addition to the volume increase achieved by inflation, a turn in the osmotic gradient also facilitated the reversible deflation, which was shown in inflation/deflation cycles. These both characteristics of the introduced microballoons are important parameter regarding the realization of micropumps and microvalves. The fixation of expanded microcapsules via recrystallization enabled the storage of entropy-elastic strain-energy, which could be utilized for pumping actions in non-aqueous media. Here, the pumping velocity depended on both, the type of surrounding medium and the applied temperature. Surrounding media that supported the fast transport of pumped liquid showed an accelerated deflation, while high temperatures further accelerate the pumping velocity. Very fast rejection of the incorporated payload was furthermore realized with pierced expanded microballoons, which were subjected to temperatures above their Tm. The possible fixation of intermediate particle sizes provide opportunities for vent constructions that allowed the precise adjustment of specific flow-rates and multiple valve openings and closings. A valve construction was realized by the insertion of a single or multiple microballoons in a microfluidic channel. A complete and a partial closing of the microballoon-valves was demonstrated as a function of the heating period. In this context, a difference between the inflation and deflation velocity was stated, summarizing slower expansion kinetics. Overall, microballoons, which presented both on-demand pumping and reversible valving by a temperature-triggered change in the capsule's volume, might be suitable components that help to design fully integrated LOC devices, due to the implementation of the control switch and controllable inflation/deflation kinetics. In comparison to other state of the art stimuli-sensitive materials, one has to highlight the microballoons capability of stabilizing almost continuously intermediate capsule sizes by simple recrystallization of the microballoon's membrane.}, language = {en} } @phdthesis{Kiemel2023, author = {Kiemel, Katrin}, title = {Zooplankton adaptations and community dynamics in space and time}, school = {Universit{\"a}t Potsdam}, year = {2023}, abstract = {In times of ongoing biodiversity loss, understanding how communities are structured and what mechanisms and local adaptations underlie the patterns we observe in nature is crucial for predicting how future ecological and anthropogenic changes might affect local and regional biodiversity. Aquatic zooplankton are a group of primary consumers that represent a critical link in the food chain, providing nutrients for the entire food web. Thus, understanding the adaptability and structure of zooplankton communities is essential. In this work, the genetic basis for the different temperature adaptations of two seasonally shifted (i.e., temperature-dependent) occurring freshwater rotifers of a formerly cryptic species complex (Brachionus calyciflorus) was investigated to understand the overall genetic diversity and evolutionary scenario for putative adaptations to different temperature regimes. Furthermore, this work aimed to clarify to what extent the different temperature adaptations may represent a niche partitioning process thus enabling co-existence. The findings were then embedded in a metacommunity context to understand how zooplankton communities assemble in a kettle hole metacommunity located in the northeastern German "Uckermark" and which underlying processes contribute to the biodiversity patterns we observe. Using a combined approach of newly generated mitochondrial resources (genomes/cds) and the analysis of a candidate gene (Heat Shock Protein 40kDa) for temperature adaptation, I showed that the global representatives of B. calyciflorus s.s.. are genetically more similar than B. fernandoi (average pairwise nucleotide diversity: 0.079 intraspecific vs. 0.257 interspecific) indicating that both species carry different standing genetic variation. In addition to differential expression in the thermotolerant B. calyciflorus s.s. and thermosensitive B. fernandoi, the HSP 40kDa also showed structural variation with eleven fixed and six positively selected sites, some of which are located in functional areas of the protein. The estimated divergence time of ~ 25-29 Myr combined with the fixed sites and a prevalence of ancestral amino acids in B. calyciflorus s.s. indicate that B. calyciflorus s.s. remained in the ancestral niche, while B. fernandoi partitioned into a new niche. The comparison of mitochondrial and nuclear markers (HPS 40kDa, ITS1, COI) revealed a hybridisation event between the two species. However, as hybridisation between the two species is rare, it can be concluded that the temporally isolated niches (i.e., seasonal-shifted occurrence) they inhabit based on their different temperature preferences most likely represent a pre-zygotic isolation mechanism that allows sympatric occurrence while maintaining species boundaries. To determine the processes underlying zooplankton community assembly, a zooplankton metacommunity comprising 24 kettle holes was sampled over a two-year period. Active (i.e., water samples) and dormant communities (i.e., dormant eggs hatched from sediment) were identified using a two-fragment DNA metabarcoding approach (COI and 18S). Species richness and diversity as well as community composition were analysed considering spatial, temporal and environmental parameters. The analysis revealed that environmental filtering based on parameters such as pH, size and location of the habitat patch (i.e., kettle hole) and surrounding field crops largely determined zooplankton community composition (explained variance: Bray-Curtis dissimilarities: 10.5\%; Jaccard dissimilarities: 12.9\%), indicating that adaptation to a particular habitat is a key feature of zooplankton species in this system. While the spatial configuration of the kettle holes played a minor role (explained variance: Bray-Curtis dissimilarities: 2.8\% and Jaccard dissimilarities: 5.5\%), the individual kettle hole sites had a significant influence on the community composition. This suggests monopolisation/priority effects (i.e., dormant communities) of certain species in individual kettle holes. As environmental filtering is the dominating process structuring zooplankton communities, this system could be significantly influenced by future land-use change, pollution and climate change.}, language = {en} } @phdthesis{Artins2023, author = {Artins, Anthony}, title = {Crosstalk between Target Of Rapamycin (TOR) and sugar signaling in Arabidopsis thaliana}, school = {Universit{\"a}t Potsdam}, pages = {125}, year = {2023}, language = {en} } @phdthesis{GonzalezDuran2023, author = {Gonzalez Duran, Enrique}, title = {Genetic control of intracellular gene transfer by DNA repair in N. tabacum}, school = {Universit{\"a}t Potsdam}, pages = {XII, 127, XLI}, year = {2023}, abstract = {Mitochondria and plastids are organelles with an endosymbiotic origin. During evolution, many genes are lost from the organellar genomes and get integrated in the nuclear genome, in what is known as intracellular/endosymbiotic gene transfer (IGT/EGT). IGT has been reproduced experimentally in Nicotiana tabacum at a gene transfer rate (GTR) of 1 event in 5 million cells, but, despite its centrality to eukaryotic evolution, there are no genetic factors known to influence the frequency of IGT in higher eukaryotes. The focus of this work was to determine the role of different DNA repair pathways of double strand break repair (DSBR) in the integration step of organellar DNA in the nuclear genome during IGT. Here, a CRISPR/Cas9 mutagenesis strategy was implemented in N. tabacum, with the aim of generating mutants in nuclear genes without expected visible phenotypes. This strategy led to the generation of a collection of independent mutants in the LIG4 (necessary for non-homologous end joining, NHEJ) and POLQ genes (necessary for microhomology mediated end joining, MMEJ). Targeting of other DSBR genes (KU70, KU80, RPA1C) generated mutants with unexpectedly strong developmental phenotypes.. These factors have telomeric roles, hinting towards a possible relationship between telomere length, and strength of developmental disruption upon loss of telomere structure in plants. The mutants were made in a genetic background encoding a plastid-encoded IGT reporter, that confers kanamycin resistance upon transfer to the nucleus. Through large scale independent experiments, increased IGT from the chloroplast to the nucleus was observed in lig4 mutants, as well as lines encoding a POLQ gene with a defective polymerase domain (polqΔPol). This shows that NHEJ or MMEJ have a double-sided relationship with IGT: while transferred genes may integrate using either pathway, the presence of both pathways suppresses IGT in wild-type somatic cells, thus demonstrating for the first time the extent on which nuclear genes control IGT frequency in plants. The IGT frequency increases in the mutants are likely mediated by increased availability of double strand breaks for integration. Additionally, kinetic analysis reveals that gene transfer (GT) events accumulate linearly as a function of time spent under antibiotic selection in the experiment, demonstrating that, contrary to what was previously thought, there is no such thing as a single GTR in somatic IGT experiments. Furthermore, IGT in tissue culture experiments appears to be the result of a "race against the clock" for integration in the nuclear genome, that starts when the organellar DNA arrives to the nucleus granting transient antibiotic resistance. GT events and escapes of kanamycin selection may be two possible outcomes from this race: those instances where the organellar DNA gets to integrate are recovered as GT events, and in those cases where timely integration fails, antibiotic resistance cannot be sustained, and end up considered as escapes. In the mutants, increased opportunities for integration in the nuclear genome change the overall ratio between IGT and escape events. The resources generated here are promising starting points for future research: (1) the mutant collection, for the further study of processes that depend on DNA repair in plants (2) the collection of GT lines obtained from these experiments, for the study of the effect of DSBR pathways over integration patterns and stability of transferred genes and (3) the developed CRISPR/Cas9 workflow for mutant generation, to make N. tabacum meet its potential as an attractive model for answering complex biological questions.}, language = {en} } @phdthesis{Piankova2022, author = {Piankova, Diana}, title = {Electron pair distribution function (ePDF) analysis and advanced transmission electron microscopy (TEM) techniques}, school = {Universit{\"a}t Potsdam}, pages = {XIX, 146}, year = {2022}, language = {en} } @phdthesis{Mariette2023, author = {Mariette, Alban}, title = {Building a wall: Developing small molecule biosensors to visualize cell wall biosynthesis and untangling mechanismus underlying nucleotide sugar transport}, school = {Universit{\"a}t Potsdam}, pages = {249}, year = {2023}, language = {en} } @phdthesis{Baum2023, author = {Baum, Katharina}, title = {Social networking sites}, school = {Universit{\"a}t Potsdam}, pages = {281}, year = {2023}, language = {en} } @phdthesis{Stoll2022, author = {Stoll, Andreas}, title = {Advanced spectroscopic instruments enabled by integrated optics}, school = {Universit{\"a}t Potsdam}, pages = {97, XV}, year = {2022}, abstract = {The aim of this work is the study of silica Arrayed Waveguide Gratings (AWGs) in the context of applications in astronomy. The specific focus lies on the investigation of the feasibility and technology limits of customized silica AWG devices for high resolution near-infrared spectroscopy. In a series of theoretical and experimental studies, AWG devices of varying geometry, foot-print and spectral resolution are constructed, simulated using a combination of a numerical beam propagation method and Fraunhofer diffraction and fabricated devices are characterized with respect to transmission efficiency, spectral resolution and polarization sensitivity. The impact of effective index non-uniformities on the performance of high-resolution AWG devices is studied numerically. Characterization results of fabricated devices are used to extrapolate the technology limits of the silica platform. The important issues of waveguide birefringence and defocus aberration are discussed theoretically and addressed experimentally by selection of an appropriate aberration-minimizing anastigmatic AWG layout structure. The drawbacks of the anastigmatic AWG geometry are discussed theoretically. From the results of the experimental studies, it is concluded that fabrication-related phase errors and waveguide birefringence are the primary limiting factors for the growth of AWG spectral resolution. It is shown that, without post-processing, the spectral resolving power is phase-error-limited to R < 40, 000 and, in the case of unpolarized light, birefringence-limited to R < 30, 000 in the AWG devices presented in this work. Necessary measures, such as special waveguide geometries and post-fabrication phase error correction are proposed for future designs. The elimination of defocus aberration using an anastigmatic AWG geometry is successfully demonstrated in experiment. Finally, a novel, non-planar dispersive in-fibre waveguide structure is proposed, discussed and studied theoretically.}, language = {en} } @phdthesis{Amen2023, author = {Amen, Rahma}, title = {Adaptive radiation in African weakly electric fish genus Campylomormyrus}, school = {Universit{\"a}t Potsdam}, pages = {XIV, 155}, year = {2023}, abstract = {The African weakly electric fish genus Campylomormyrus includes 15 described species mostly native to the Congo River and its tributaries. They are considered sympatric species, because their distribution area overlaps. These species generate species-specific electric organ discharges (EODs) varying in waveform characteristics, including duration, polarity, and phase number. They exhibit also pronounced divergence in their snout, i.e. the length, thickness, and curvature. The diversifications in these two phenotypical traits (EOD and snout) have been proposed as key factors promoting adaptive radiation in Campylomormyrus. The role of EODs as a pre-zygotic isolation mechanism driving sympatric speciation by promoting assortative mating has been examined using behavioral, genetical, and histological approaches. However, the evolutionary effects of the snout morphology and its link to species divergence have not been closely examined. Hence, the main objective of this study is to investigate the effect of snout morphology diversification and its correlated EOD to better understand their sympatric speciation and evolutionary drivers. Moreover, I aim to utilize the intragenus and intergenus hybrids of Campylomormyrus to better understand trait divergence as well as underlying molecular/genetic mechanisms involved in the radiation scenario. To this end, I utilized three different approaches: feeding behavior analysis, diet assessment, and geometric morphometrics analysis. I performed feeding behavior experiments to evaluate the concept of the phenotype-environment correlation by testing whether Campylomormyrus species show substrate preferences. The behavioral experiments showed that the short snout species exhibits preference to sandy substrate, the long snout species prefers a stone substrate, and the species with intermediate snout size does not exhibit any substrate preference. The experiments suggest that the diverse feeding apparatus in the genus Campylomormyrus may have evolved in adaptation to their microhabitats. I also performed diet assessments of sympatric Campylomormyrus species and a sister genus species (Gnathonemus petersii) with markedly different snout morphologies and EOD using NGS-based DNA metabarcoding of their stomach contents. The diet of each species was documented showing that aquatic insects such as dipterans, coleopterans and trichopterans represent the major diet component. The results showed also that all species are able to exploit diverse food niches in their habitats. However, comparing the diet overlap indices showed that different snout morphologies and the associated divergence in the EOD translated into different prey spectra. These results further support the idea that the EOD could be a 'magic trait' triggering both adaptation and reproductive isolation. Geometric morphometrics method was also used to compare the phenotypical shape traits of the F1 intragenus (Campylomormyrus) and intergenus (Campylomormyrus species and Gnathonemus petersii) hybrids relative to their parents. The hybrids of these species were well separated based on the morphological traits, however the hybrid phenotypic traits were closer to the short-snouted species. In addition, the likelihood that the short snout expressed in the hybrids increases with increasing the genetic distance of the parental species. The results confirmed that additive effects produce intermediate phenotypes in F1-hybrids. It seems, therefore, that morphological shape traits in hybrids, unlike the physiological traits, were not expressed straightforward.}, language = {en} } @phdthesis{Kaminski2023, author = {Kaminski, Roland}, title = {Complex reasoning with answer set programming}, school = {Universit{\"a}t Potsdam}, pages = {301}, year = {2023}, abstract = {Answer Set Programming (ASP) allows us to address knowledge-intensive search and optimization problems in a declarative way due to its integrated modeling, grounding, and solving workflow. A problem is modeled using a rule based language and then grounded and solved. Solving results in a set of stable models that correspond to solutions of the modeled problem. In this thesis, we present the design and implementation of the clingo system---perhaps, the most widely used ASP system. It features a rich modeling language originating from the field of knowledge representation and reasoning, efficient grounding algorithms based on database evaluation techniques, and high performance solving algorithms based on Boolean satisfiability (SAT) solving technology. The contributions of this thesis lie in the design of the modeling language, the design and implementation of the grounding algorithms, and the design and implementation of an Application Programmable Interface (API) facilitating the use of ASP in real world applications and the implementation of complex forms of reasoning beyond the traditional ASP workflow.}, language = {en} } @phdthesis{HannesVincent2022, author = {Hannes-Vincent, Krause}, title = {Social networking site use and well-being - a nuanced understanding of a complex relationship}, school = {Universit{\"a}t Potsdam}, year = {2022}, abstract = {Social Networking Sites (SNSs) are ubiquitous and attract an enormous chair of the digital population. Their functionalities allow users to connect and interact with others and weave complex social networks in which social information is continuously disseminated between users. Besides the social value SNSs are generating, they likewise attract companies and allow for new forms of marketing, thereby creating considerable economic value alike. However, as SNSs grew in popularity, so did concerns about the impact of their use on social interactions in general and the well-being of individual users in particular. While existing scientific evidence points to both risk as well as benefits of SNS use, research still lacks a profound understanding of which aspects of SNSs enable an impact on well-being and which psychological processes on the part of the users underly and explain this relationship. Therefore, this thesis is dedicated to an in-depth exploration of the relationship between SNS use and well-being and aims to answer how SNS use can impact well-being. Primarily, it focuses on the unique technological features that characterize SNSs and enable potential well- being alterations and on specific psychological processes on the part of the users, underlying and explaining the relationship. For this purpose, the thesis first introduces the concept of well- being. It continues by presenting SNSs' unique technological features, divided into specifics of the content disseminated on SNSs and the network structure of SNSs. Further, the thesis introduces three classes of psychological processes assumed most relevant for the relationship between SNSs and well-being: other-focused, self-focused, and contrastive processes.. It is assumed that the course and quality of these common processes change in the SNS context and that a complex interplay between the unique features of SNSs and these processes determines how SNSs may ultimately affect users' well-being - both in positive and negative ways. The dissertation comprises seven research articles, each of which focusses on a particular set of SNS characteristics, their interplay with one or more of the proposed psychological processes, and ultimately the resulting effects on user well-being or its key resilience and risk factors. The seven articles investigate this relationship using different methodological approaches. Three articles are based on either systematic or narrative literature reviews, one applies an empirical cross-sectional research design, and three articles present an experimental investigation. Thematically, two articles revolve around SNS use's effect on self-esteem. Three articles examine the specific role of the emotion of envy and its potential to establish and perpetuate a well-being-damaging social climate on SNSs. The two last articles of this thesis revolve around the established assumption that active and passive SNS use, as different modalities of SNS use, cause differential effects on users' well-being due to the involvement of different psychological processes. The results of this thesis illustrate different ways how SNSs can affect users' well-being. The results suggest that especially contrastive processes play a decisive role in explaining potential well-being risks for SNS users. Their interplay with certain SNS features seems to foster upward social comparisons and feelings of envy, potentially leading to a complex set of deleterious effects on users' well-being. At the same time, the findings illuminate ways in which SNSs can benefit users and their self-esteem - especially when SNS use promotes self- focused and social-feedback-based other-focused processes. The thesis and their findings illustrate that the relationship between SNSs and well-being is complex. Therefore, a nuanced perspective, taking into consideration both the technological uniqueness of SNSs and the psychological processes they are enabling, is crucial to understand how these technologies affect their users in good and potentially harmful ways. On the one hand, the gathered insights contribute to research, providing novel insights into the complex relationship between SNS use and well-being. On the other hand, the results enable a focused and action-oriented derivation of recommendations for stakeholders such as individual users, policymakers, and platform providers. The findings of this thesis can help them to better combat SNS-related risks and ultimately ensure a healthy and sustainable environment for users - and thus also the economic values of SNSs - in the long term.}, language = {en} } @phdthesis{Esfahani2022, author = {Esfahani, Reza Dokht Dolatabadi}, title = {Time-dependent monitoring of near-surface and ground motion modelling: developing new data processing approaches based on Music Information Retrieval (MIR) strategies}, doi = {10.25932/publishup-56767}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-567671}, school = {Universit{\"a}t Potsdam}, pages = {xiv, 107}, year = {2022}, abstract = {Seismology, like many scientific fields, e.g., music information retrieval and speech signal pro- cessing, is experiencing exponential growth in the amount of data acquired by modern seismo- logical networks. In this thesis, I take advantage of the opportunities offered by "big data" and by the methods developed in the areas of music information retrieval and machine learning to predict better the ground motion generated by earthquakes and to study the properties of the surface layers of the Earth. In order to better predict seismic ground motions, I propose two approaches based on unsupervised deep learning methods, an autoencoder network and Generative Adversarial Networks. The autoencoder technique explores a massive amount of ground motion data, evaluates the required parameters, and generates synthetic ground motion data in the Fourier amplitude spectra (FAS) domain. This method is tested on two synthetic datasets and one real dataset. The application on the real dataset shows that the substantial information contained within the FAS data can be encoded to a four to the five-dimensional manifold. Consequently, only a few independent parameters are required for efficient ground motion prediction. I also propose a method based on Conditional Generative Adversarial Networks (CGAN) for simulating ground motion records in the time-frequency and time domains. CGAN generates the time-frequency domains based on the parameters: magnitude, distance, and shear wave velocities to 30 m depth (VS30). After generating the amplitude of the time-frequency domains using the CGAN model, instead of classical conventional methods that assume the amplitude spectra with a random phase spectrum, the phase of the time-frequency domains is recovered by minimizing the observed and reconstructed spectrograms. In the second part of this dissertation, I propose two methods for the monitoring and characterization of near-surface materials and site effect analyses. I implement an autocorrelation function and an interferometry method to monitor the velocity changes of near-surface materials resulting from the Kumamoto earthquake sequence (Japan, 2016). The observed seismic velocity changes during the strong shaking are due to the non-linear response of the near-surface materials. The results show that the velocity changes lasted for about two months after the Kumamoto mainshock. Furthermore, I used the velocity changes to evaluate the in-situ strain-stress relationship. I also propose a method for assessing the site proxy "VS30" using non-invasive analysis. In the proposed method, a dispersion curve of surface waves is inverted to estimate the shear wave velocity of the subsurface. This method is based on the Dix-like linear operators, which relate the shear wave velocity to the phase velocity. The proposed method is fast, efficient, and stable. All of the methods presented in this work can be used for processing "big data" in seismology and for the analysis of weak and strong ground motion data, to predict ground shaking, and to analyze site responses by considering potential time dependencies and nonlinearities.}, language = {en} } @phdthesis{Mahto2022, author = {Mahto, Harendra}, title = {In vitro analysis of Early Starvation 1 (ESV1) and Like Early Starvation 1 (LESV) on starch degradation with focus on glucan, water dikinase (GWD) and phosphoglucan, water dikinase (PWD)}, pages = {167}, year = {2022}, abstract = {Starch is an insoluble polyglucan, comprises of two polymers, namely, the branched α-1,4: α-1,6-D-glucan amylopectin and the almost unbranched α-1,4-D-glucan amylose. The growth of all plants is directly dependent on the accumulation of transitory starch during the daytime when photosynthesis takes place and subsequently starch degradation during the night. Starch phosphorylation takes place by starch-related dikinases called α-glucan, water dikinase (GWD), and phosphoglucan, water dikinase (PWD), and is a very important step in starch degradation. The biochemical mechanisms of phosphorylation of starch are not properly understood. Recent studies have found that there are two starch binding proteins namely, Early Starvation1 (ESV1) and Like Early Starvation1 (LESV), which play an important role in starch metabolism. It has been shown that ESV1 and LESV proteins affect the starch phosphorylation activity of GWD and PWD enzymes, which control the rate of degradation of starch granules. In this thesis, various in vitro assays were performed to identify and understand the mechanism of recombinant proteins; ESV1 and LESV on the starch degradation. The starch degradation was performed by phosphorylation enzymes, GWD and PWD separately. In various enzymatic assays, the influence of the ESV1 and LESV on the actions of GWD and PWD on the surfaces of different native starch granules were analysed. Furthermore, ESV1 and LESV have specifically shown influences on the phosphorylation activities of GWD and PWD on the starch granule surfaces in an antagonistic pattern in such a way that, the GWD mediated phosphorylation were significantly reduced while PWD mediated phosphorylation were significantly increased respectively. In another set of experiments, ISA and BAM hydrolyzing enzymes were used to alter the structure of starch, and then determine the effect of both dikinases mediated phosphorylation in the presence of ESV1 and LESV on the altered starch granules surfaces. In these results, significant decreases in both GWD and PWD mediated phosphorylation were observed in all the treatments containing either ESV1 or LESV proteins only or both ESV1 and LESV. It was also found that LESV preferentially binds to both amylose and amylopectin, while ESV1 binds to highly ordered glucans such as maltodextrins and amylopectin, which are crystalline in structure. Both ESV1 or LESV proteins either individually or in combination have shown influence on the activity of GWD and PWD phosphate incorporation into the starch granules via reduction even though at different percentages depending on the sources of starch, therefore it is difficult to distinguish the specific function between them. The biochemical studies have shown that protein-glucan interaction specifically between ESV1 or LESV or in combination with different species of starch granules has very strong surface binding, or it might be possible that both the proteins not only bind to the surface of the starch granules but also have entered deep inside the glucan structure of the starch granules. However, the results also revealed that ESV1 and LESV did not alter the autophosphorylation of the dikinases. Also, the chain length distribution pattern of the released glucan chains after treatment of starch with ISA enzyme was evaluated with respect to the degree of polymerization (DP) of the different starch granules. Capillary electrophoresis was employed to study the effect of LESV and ESV1 on the chain length distribution. In summary, this study confirms that ESV1 and LESV play an important role in organizing and regulating the starch metabolism process. In the later half, studies were performed to monitor whether the metabolism of carbohydrates and partitioning, contribute to the higher salt tolerance of the facultative halophyte Hordeum marinum when compared to glycophyte Hordeum vulgare. Seedlings with the same size from both species were hydroponically grown at 0, 150, and 300 mM of NaCl for 3 weeks. H. marinum maintained a high relative growth rate, which was found concomitant in higher aptitude plants to maintain efficient shoot tissue hydration and integrity of membrane under salt conditions when compared to H. vulgare. Hence, our data suggested that the change in the starch storage, distribution of soluble sugar concentrations between source and sink organs, and also changes in the level of enzymes involved in the starch metabolism was significant to give insights into the importance of carbohydrate metabolism in barley species with regards to the salt tolerance. Although these results are still in their nascent state, it could be vital for other researchers to formulate future studies. The preliminary results which were studies about the carbohydrate metabolism and partitioning in salt responses in the halophyte H. marinum and the glycophyte H. vulgare revealed that salt tolerance in barley species is not due to osmotic adjustments, but due to other reasons that were not explored in the past studies. However, the activity of DPE2 in H. vulgare was not hampered by the presence of NaCl as observed. While Pho1 and Pho2, activities were highly increased in cultivated barley. These findings could be suggestive of a possible role of these enzymes in the responses of carbohydrate metabolism to salinity. When sea and cultivated barley species were compared, it was discovered that the former had more versatility in carbohydrate metabolism and distribution.}, language = {en} } @phdthesis{Jung2022, author = {Jung, Jana}, title = {Does youth matter?}, pages = {176}, year = {2022}, abstract = {This dissertation is a compilation of publications and submitted publication manuscripts that seek to improve the understanding of modern partnership trajectories. Romantic relationships constitute one of the most important dimensions in a person's life. They serve to satisfy social and emotional needs (Arr{\´a}nz Becker, 2008) and have an impact on various other dimensions of life. Since the 1970s, partnership formation has been characterized by increased heterogeneity, has become less ordered and much more diverse in terms of living arrangements and the number of unions across the life course (Helske et al, 2015; Ross et al, 2009). This dissertation argues that while partnerships have become more unstable, the need for attachment and the importance of relationship have remained high, if not increased, as evidenced by the prevalence of couple relationships that have remained quite stable (Eckhardt, 2015). The life course perspective (Elder, 1994; Elder et al., 2004; Mayer, 2009) offers an appropriate framework for the understanding of partnership formations throughout the life course. This perspective stresses the path dependency of the life course as well as the interdependencies of life domains (Bernardi et al., 2019). Thus, it can be argued that conditions, resources, and experiences in youth have a substantial influence on later life course outcomes. Given the increasing heterogeneity of partnership trajectories, research to understand partnership processes cannot be based only on single events (e.g., marriage or divorce) or life stages, but must be explored in a dynamic context and over a longer period of time. In sum, this thesis argues that partnership trajectories have to be considered from a holistic perspective. Not only single transitions or events are useful to describe modern partnership histories adequately, but rather the whole process. Additionally, as partnership trajectories are linked to various outcomes (e.g., economics, health, effects on children), it is therefore highly relevant to improve our understanding of partnership dynamics and their determinants and consequences. Findings in this field of research contribute to a better understanding of how childhood and youth are of prospective importance for the later partnership trajectories and whether there are any long-term effects of the conditions and resources formed and stabilized in youth, which then help to understand and explain partnership dynamics. Thus, the interest of this thesis lies in the longitudinal description and prediction of the dynamics of partnership trajectories in light of the individual resources formed and stabilized in youth, as well as in the investigation of the consequences of different partnership trajectory patterns on individual well-being. For these objectives, a high demand on the data is required, as prospective data at the beginning of the partnership biography are needed, as well as data on current life dimensions and the detailed partnership history. The German LifE Study provides this particular data structure as it examines life courses of more than 1,300 individuals from adolescence to middle adulthood. With regard to the overall aim of this dissertation, the main conclusion is that early life conditions, experiences, and resources influence the dynamics of individual partnership trajectories. The results illustrate that youth matters and that characteristics and resources anchored in youth influence the timing of early status passages, which sets individuals on specific life paths. However, in addition to personal and social resources, partnership trajectories were also significantly influenced by individuals' sociodemographic placement. Additionally, individual resources are also linked to the overall turbulence or stability of partnership trajectories. This overall dynamic, which is reflected in different partnership patterns, influences individual well-being, with stability being associated with greater satisfaction, and instability (women), or permanent singlehood (men), having a negative impact on well-being. My analyses contribute to life course research by examining path dependency against the background of various individual factors (socio-structural and psychological characteristics) to model decision-making processes in partnerships in more detail. They do so by including also non-cohabitational union types in the analyses, by accounting for pre-trajectory life conditions and resources, and, most importantly, by modeling the partnership trajectory in a holistic and dynamic perspective, applying this perspective to appropriate and modern statistical methods on a unique dataset.}, language = {en} } @phdthesis{Zhou2022, author = {Zhou, Shuo}, title = {Biological evaluation and sulfation of polymer networks from glycerol glycidyl ether}, school = {Universit{\"a}t Potsdam}, pages = {96}, year = {2022}, abstract = {Cardiovascular diseases are the main cause of death worldwide, and their prevalence is expected to rise in the coming years. Polymer-based artificial replacements have been widely used for the treatment of cardiovascular diseases. Coagulation and thrombus formation on the interfaces between the materials and the human physiological environment are key issues leading to the failure of the medical device in clinical implantation. The surface properties of the materials have a strong influence on the protein adsorption and can direct the blood cell adhesion behavior on the interfaces. Furthermore, implant-associated infections will be induced by bacterial adhesion and subsequent biofilm formation at the implantation site. Thus, it is important to improve the hemocompatibility of an implant by altering the surface properties. One of the effective strategies is surface passivation to achieve protein/cell repelling ability to reduce the risk of thrombosis. This thesis consists of synthesis, functionalization, sterilization, and biological evaluation of bulk poly(glycerol glycidyl ether) (polyGGE), which is a highly crosslinked polyether-based polymer synthesized by cationic ring-opening polymerization. PolyGGE is hypothesized to be able to resist plasma protein adsorption and bacterial adhesion due to analogous chemical structure as polyethylene glycol and hyperbranched polyglycerol. Hydroxyl end groups of polyGGE provide possibilities to be functionalized with sulfates to mimic the anti-thrombogenic function of the endothelial glycocalyx. PolyGGE was synthesized by polymerization of the commercially available monomer glycerol glycidyl ether, which was characterized as a mixture of mono-, di- and tri-glycidyl ether. Cationic ring opening-polymerization of this monomer was carried out by ultraviolet (UV) initiation of the photo-initiator diphenyliodonium hexafluorophosphate. With the increased UV curing time, more epoxides in the side chains of the monomers participated in chemical crosslinking, resulting in an increase of Young's modulus, while the value of elongation at break of polyGGE first increased due to the propagation of the polymer chains then decreased with the increase of crosslinking density. Eventually, the chain propagation can be effectively terminated by potassium hydroxide aqueous solution. PolyGGE exhibited different tensile properties in hydrated conditions at body temperature compared to the values in the dry state at room temperature. Both Young's modulus and values of elongation at break were remarkably reduced when tested in water at 37 °C, which was above the glass transition temperature of polyGGE. At physiological conditions, entanglements of the ployGGE networks unfolded and the free volume of networks were replaced by water molecules as softener, which increased the mobility of the polymer chains, resulting in a lower Young's modulus. Protein adsorption analysis was performed on polyGGE films with 30 min UV curing using an enzyme-linked immunosorbent assay. PolyGGE could effectively prevent the adsorption of human plasma fibrinogen, albumin, and fibronectin at the interface of human plasma and polyGGE films. The protein resistance of polyGGE was comparable to the negative controls: the hemocompatible polydimethylsiloxane (PDMS), showing its potential as a coating material for cardiovascular implants. Moreover, antimicrobial tests of bacterial activity using isothermal microcalorimetry and the microscopic image of direct bacteria culturing demonstrated that polyGGE could directly interfere biofilm formation and growth of both Gram-negative and antibiotic-resistant Gram-positive bacteria, indicating the potential application of polyGGE for combating the risk of hospital-acquired infections and preventing drug-resistant superbug spreading. To investigate its cell compatibility, polyGGE films were extracted by different solvents (ethanol, chloroform, acetone) and cell culture medium. Indirect cytotoxicity tests showed extracted polyGGE films still had toxic effects on L929 fibroblast cells. High-performance liquid chromatography/electrospray ionization mass spectrometry revealed the occurrence of organochlorine-containing compounds released during the polymer-cell culture medium interaction. A constant level of those organochlorine-containing compounds was confirmed from GGE monomer by a specific peak of C-Cl stretching in infrared spectra of GGE. This is assumed to be the main reason causing the increased cell membrane permeability and decreased metabolic activity, leading to cell death. Attempts as changing solvents were made to remove toxic substances, however, the release of these small molecules seems to be sluggish. The densely crosslinked polyGGE networks can possibly contribute to the trapping of organochlorine-containing compounds. These results provide valuable information for exploring the potentially toxic substances, leaching from polyGGE networks, and propose a feasible strategy for minimizing the cytotoxicity via reducing their crosslinking density. Sulfamic acid/ N-Methyl-2-pyrrolidone (NMP) were selected as the reagents for the sulfation of polyGGE surfaces. Fourier transform attenuated total reflection infrared spectroscopy (ATR-FT-IR) was used to monitor the functionalization kinetics and the results confirmed the successful sulfate grafting on the surface of polyGGE with the covalent bond -C-O-S-. X-ray photoelectron spectroscopy was used to determine the element composition on the surface and the cross-section of the functionalized polyGGE and sulfation within 15 min guarantees the sulfation only takes place on the surface while not occurring in the bulk of the polymer. The concentration of grafted sulfates increased with the increasing reaction time. The hydrophilicity of the surface of polyGGE was highly increased due to the increase of negatively charged end groups. Three sterilization techniques including autoclaving, gamma irradiation, and ethylene oxide (EtO) sterilization were used for polyGGE sulfates. Results from ATR-FT-IR and Toluidine Blue O quantitative assay demonstrated the total loss of the sulfates after autoclave sterilization, which was also confirmed by the increased water contact angle. Little influence on the concentration of sulfates was found for gamma-irradiated and autoclaving sterilized polyGGE sulfates. To investigate the thermal influence on polyGGE sulfates, one strategy was to use poly(hydroxyethyl acrylate) sulfates (PHEAS) for modeling. The thermogravimetric analysis profile of PHEAS demonstrated that sulfates are not thermally stable independent of the substrate materials and decomposition of sulfates occurs at around 100 °C. Although gamma irradiation also showed little negative effect on the sulfate content, the color change in the polyGGE sulfates indicates chemical or physical change might occur in the polymer. EtO sterilization was validated as the most suitable sterilization technique to maintain the chemical structure of polyGGE sulfates. In conclusion, the conducted work proved that bulk polyGGE can be used as an antifouling coating material and shows its antimicrobial potential. Sulfates functionalization can be effectively realized using sulfamic acid/NMP. EtO sterilization is the most suitable sterilization technique for grafted sulfates. Besides, this thesis also offers a good strategy for the analysis of toxic leachable substances using suitable physicochemical characterization techniques. Future work will focus on minimizing/eliminating the release of toxic substances via reducing the crosslinking density. Another interesting aspect is to study whether grafted sulfates can meet the need for anti-thrombogenicity.}, language = {en} } @phdthesis{Oehlschlaeger2022, author = {Oehlschl{\"a}ger, Patricia}, title = {Future perspectives on business negotiations}, series = {Schriftenreihe zum Verhandlungsmanagement}, journal = {Schriftenreihe zum Verhandlungsmanagement}, number = {19}, publisher = {Kovac}, address = {Hamburg}, isbn = {978-3-339-13256-7}, issn = {2365-7898}, pages = {173}, year = {2022}, abstract = {Despite the importance of negotiations in companies and their contribution to strategic corporate planning, researchers have not yet focused on assessing the development of negotiations in the future. To broaden the field of futures research in negotiations and to provide empirical guidance about strategic business decisions to negotiators and managers, this work exploratively investigates the future of negotiations. The impact of trends on negotiations and negotiation behavior, as well as the development of future negotiation scenarios are therefore examined. Moreover, the preparation of negotiators for the future is analyzed and how effective negotiation teaching can be designed to improve negotiation performance.}, language = {en} } @phdthesis{Madoerin2022, author = {Mad{\"o}rin, Anouk}, title = {Postcolonial surveillance}, series = {Challenging Migration Studies}, journal = {Challenging Migration Studies}, publisher = {Rowman \& Littlefield}, address = {London}, isbn = {978-1-5381-6503-4}, school = {Universit{\"a}t Potsdam}, pages = {xix, 167}, year = {2022}, abstract = {Postcolonial Surveillance investigates the long history of the European border regime, focusing on the colonial forerunners of today's border technologies. The book takes a longue dur{\´e}e perspective to uncover how Europe's colonial history continues to shape the high-tech political present and has morphed into EU border migration policies, border security, and surveillance apparatuses. It exposes the racial hierarchies and power relations that form these systems and highlights key moments when the past and present interact and collide, such as in panoptic surveillance, biopolitical registers, biometric sorting, and deterrent media infrastructure. The technological genealogies assembled in this book reveal the unacknowledged histories that had to be rejected for the seemingly clean, unbiased, and neutral technologies to emerge as such.}, language = {en} } @phdthesis{Spaeker2022, author = {Sp{\"a}ker, Oliver C.}, title = {Structure-property-function relationships in the cornea of Limulus polyphemus}, pages = {VIII, 110, A16}, year = {2022}, language = {en} } @phdthesis{Tung2021, author = {Tung, Wing Tai}, title = {Polymeric fibrous scaffold on macro/microscale towards tissue regeneration}, school = {Universit{\"a}t Potsdam}, year = {2021}, language = {en} } @phdthesis{Knoche2022, author = {Knoche, Lisa}, title = {Untersuchung von Transformationsprodukten ausgew{\"a}hlter Tierarzneimittel generiert durch Elektrochemie, Mikrosomal Assay, Hydrolyse und Photolyse}, pages = {163, III}, year = {2022}, abstract = {The knowledge of transformation pathways and transformation products of veterinary drugs is important for health, food and environmental matters. Residues, consisting of original veterinary drug and transformation products, are found in food products of animal origin as well as the environment (e.g., soil or surface water). Several transformation processes can alter the original veterinary drug, ranging from biotransformation in living organism to environmental degradation processes like photolysis, hydrolysis, or microbial processes. In this thesis, four veterinary drugs were investigated, three ionophore antibiotics Monensin, Salinomycin and Lasalocid and the macrocyclic lactone Moxidectin. Ionophore antibiotics are mainly used to cure and prevent coccidiosis in poultry especially prophylactic in broiler farming. Moxidectin is an antiparasitic drug that is used for the treatment of internal and external parasites in food-producing and companion animals. The main objective of this work is to employ different laboratory approaches to generate and identify transformation products. The identification was conducted using high-resolution mass spectrometry (HRMS). A major focus was placed on the application of electrochemistry for simulation of transformation processes. The electrochemical reactor - equipped with a three-electrode flow-through cell - enabled the oxidation or reduction by applying a potential. The transformation products derived were analyzed by online coupling of the electrochemical reactor and a HRMS and offline by liquid chromatography (LC) combined with HRMS. The main modification reaction of the identified transformation products differed for each investigated veterinary drug. Monensin showed decarboxylation and demethylation as the main modification reactions, for Salinomycin mostly decarbonylation occurred and for Lasalocid methylation was prevalent. For Moxidectin, I observed an oxidation (hydroxylation) reaction and adduct formation with solvent. In general, for Salinomycin and Lasalocid, more transient transformation products (online measurement) than stable transformation products (offline measurements) were detected. By contrast, the number of transformation products using online and offline measurements were identical for Monensin and Moxidectin. As a complementary approach, metabolism tests with rat or human liver microsomes were conducted for the ionophore antibiotics. Monensin was investigated by using rat liver microsomes and the transformation products identified were based on decarboxylation and demethylation. Salinomycin and Lasalocid were converted by human and rat liver microsomes. For both substances, more transformation products were found by using human liver microsomes. The transformation products of the rat liver microsome conversion were redundant, and the transformation products were also found at the human liver microsome assay. Oxidation (hydroxylation) was found to be the main modification reaction for both. In addition, a frequent ion exchange between sodium and potassium was identified. The final two experiments were performed for one substance each, whereby the hydrolysis of Monensin and the photolysis of Moxidectin was investigated. The transformation products of the pH-dependent hydrolysis were based on ring-opening and dehydration. Moxidectin formed several transformation products by irradiation with UV-C light and the main modification reactions were isomeric changes, (de-)hydration and changes of the methoxime moiety. In summary, transformation products of the four investigated veterinary drugs were generated by the different laboratory approaches. Most of the transformation products were identified for the first time. The resulting findings provide an improved understanding of clarifying the transformation behavior.}, language = {en} } @phdthesis{Kashgar2022, author = {Kashgar, Maral}, title = {The Transfer of Conflict-Related Detainees}, series = {Schriften des MenschenRechtsZentrums der Universit{\"a}t Potsdam}, volume = {48}, journal = {Schriften des MenschenRechtsZentrums der Universit{\"a}t Potsdam}, publisher = {Nomos}, address = {Baden-Baden}, isbn = {978-3-8487-8507-0}, school = {Universit{\"a}t Potsdam}, pages = {449}, year = {2022}, abstract = {Die Arbeit untersucht bewaffnete Konfliktszenarien, in denen an multinationalen Milit{\"a}roperationen beteiligte Staaten w{\"a}hrend einer Gewahrsamsoperation gegnerische Kr{\"a}fte oder andere Personen in Gewahrsam nehmen und diese dann an die Kr{\"a}fte eines anderen Staates, oftmals der Hostnation mit zweifelhafter Menschenrechtsreputation, {\"u}berstellen. Gewahrsamspersonen laufen dann Gefahr, Opfer erheblicher Rechtsverletzungen zu werden}, language = {en} } @phdthesis{Schell2022, author = {Schell, Mareike}, title = {Investigating the effect of Lactobacillus rhamnosus GG on emotional behavior in diet-induced obese C57BL/6N mice}, school = {Universit{\"a}t Potsdam}, pages = {XVI, 117}, year = {2022}, abstract = {The prevalence of depression and anxiety is increased in obese patients compared to healthy humans, which is partially due to a shared pathogenesis, including insulin resistance and inflammation. These factors are also linked to intestinal dysbiosis. Additionally, the chronic consumption of diets rich in saturated fats results in body weight gain, hormonal resistances and unfavorable changes in the microbiome composition. The intake of Lactobacilli has already been shown to improve dysbiosis along with metabolism and mood. Yet, the beneficial role and the underlying mechanism of Lactobacillus rhamnosus GG (LGG) to improve emotional behavior in established diet-induced obese conditions are, so far, unknown. To characterize the role of LGG in diet-induced obesity, female and male C57BL/6N mice were fed a semi-synthetic low-fat diet (LFD, 10 \% kcal from fat) or a conventional high-fat diet (HFD, 45 \% kcal from fat) for initial 6 weeks, which was followed by daily oral gavage of vehicle or 1x10^8 CFU of LGG until the end of the experiment. Mice were subjected to basic metabolic and extensive behavioral phenotyping, with a focus on emotional behavior. Moreover, composition of cecal gut microbiome, metabolomic profile in plasma and cerebrospinal fluid was investigated and followed by molecular analyses. Both HFD-feeding and LGG application resulted in sex-specific differences. While LGG prevented the increase of plasma insulin, adrenal gland weight and hyperactivity in diet-induced obese female mice, there was no regulation of anxiodepressive-like behavior. In contrast, metabolism of male mice did not benefit from LGG application, but strikingly, LGG decreased specifically depressive-like behavior in the Mousetail Suspension Test which was confirmed by the Splash Test characterizing motivation for 'self-care'. The microbiome analysis in male mice revealed that HFD-feeding, but not LGG application, altered cecal microbiome composition, indicating a direct effect of LGG on behavioral regulation. However, in female mice, both HFD-feeding and LGG application resulted in changes of microbiome composition, which presumably affected metabolism. Moreover, as diet-induced obese female mice unexpectedly did not exhibit anxiodepressive-like behavior, follow-up analyses were conducted in male mice. Here, HFD-feeding significantly altered abundance of plasma lipids whereas LGG decreased branched chain amino acids which associated with improved emotional behavior. In nucleus accumbens (NAcc) and VTA/SN, which belong to the dopaminergic system, LGG restored HFD-induced decrease of tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis, on gene expression level. Lastly, transcriptome analysis in the NAcc identified gene expression of cholecystokinin as a potential mediator of the effect of LGG on HFD-induced emotional alterations. In summary, this thesis revealed the beneficial effects of LGG application on emotional alterations in established diet-induced obesity. Furthermore, both HFD-feeding and LGG treatment exhibited sex-specific effects, resulting in metabolic improvements in female mice while LGG application mitigated depressive-like behavior in obese male mice along with a molecular signature of restored dopamine synthesis and neuropeptide signaling.}, language = {en} } @phdthesis{Wang2022, author = {Wang, Yang}, title = {Role of the actin cytoskeleton in cellular morphogenesis at the shoot apical meristem of Arabidopsis thaliana}, doi = {10.25932/publishup-55908}, school = {Universit{\"a}t Potsdam}, pages = {130}, year = {2022}, abstract = {The morphogenesis of sessile plants is mainly driven by directional cell growth and cell division. The organization of their cytoskeleton and the mechanical properties of the cell wall greatly influence morphogenetic events in plants. It is well known that cortical microtubules (CMTs) contribute to directional growth by regulating the deposition of the cellulose microfibrils, as major cell wall fortifying elements. More recent findings demonstrate that mechanical stresses existing in cells and tissues influence microtubule organization. Also, in dividing cells, mechanical stress directions contribute to the orientation of the new cell wall. In comparison to the microtubule cytoskeleton, the role of the actin cytoskeleton in regulating shoot meristem morphogenesis has not been extensively studied. This thesis focuses on the functional relevance of the actin cytoskeleton during cell and tissue scale morphogenesis in the shoot apical meristem (SAM) of Arabidopsis thaliana. Visualization of transcriptional reporters indicates that ACTIN2 and ACTIN7 are two highly expressed actin genes in the SAM. A link between the actin cytoskeleton and SAM development derives from the observation that the act2-1 act7-1 double mutant has abnormal cell shape and perturbed phyllotactic patterns. Live-cell imaging of the actin cytoskeleton further shows that its organization correlates with cell shape, which indicates a potential role of actin in influencing cellular morphogenesis. In this thesis, a detailed characterization of the act2-1 act7-1 mutant reveals that perturbation of actin leads to more rectangular cellular geometries with more 90° cell internal angles, and higher incidences of four-way junctions (four cell boundaries intersecting together). This observation deviates from the conventional tricellular junctions found in epidermal cells. Quantitative cellular-level growth data indicates that such differences in the act2-1 act7-1 mutant arise due to the reduced accuracy in the placement of the new cell wall, as well as its mechanical maturation. Changes in cellular morphology observed in the act2-1 act7-1 mutant result in cell packing defects that subsequently compromise the flow of information among cells in the SAM.}, language = {en} } @phdthesis{Pan2022, author = {Pan, Yufeng}, title = {Genetic and molecular analysis of heat stress induced transcriptional memory}, doi = {10.25932/publishup-56011}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-560119}, school = {Universit{\"a}t Potsdam}, pages = {XIII, 113}, year = {2022}, abstract = {Heat stress (HS) is one of the most common abiotic stresses, frequently affecting plant growth and crop production. With its fluctuating nature, HS episodes are frequently interspersed by stress-free intervals. Plants can be primed by HS, allowing them to survive better a recurrent stress episode. A memory of this priming can be maintained during stress-free intervals and this memory is closely correlated with transcriptional memory at several HS-inducible loci. This transcriptional memory is evident from hyper-induction of a locus upon a recurrent HS. ASCORBATE PEROXIDASE 2 (APX2) shows such hyper-induction upon recurring HS, however, the molecular basis of this transcriptional memory is not understood. Previous research showed that the HSinduced transcriptional memory at APX2 can last for up to seven days, and that it is controlled by cis-regulatory elements within the APX2 promoter. To identify regulators involved in HS transcriptional memory, an unbiased forward genetic screening using EMS mutated seeds of pAPX2::LUC was performed from this screen. Two EMS mutants with affected transcriptional memory of LUC were identified. I confirmed that both two EMS mutants resulted from the gene mutations of HISTONE ACETYLTRANSFERASE 1 (HAC1). Besides pAPX2::LUC, the HS-induced transcription of other HS memory genes were also affected in hac1 mutants. Moreover, HAC1 may promote HS transcriptional memory by acetylating promoters of HS memory genes. On the other hand, to identify cis-regulatory elements that are required for transcriptional memory of APX2, I performed promoter analysis of the four conserved HSEs identified within a functional APX2 promoter. I found out that one of the HSEs (HSE1) is necessary for both HS-induced APX2 transcription and transcriptional memory, while another one of HSEs (HSE2) is important for HS-induced APX2 transcriptional memory. I also found out that the HSE1 itself (with 10 bp of flanking sequence) is sufficient to confer HS-induced APX2 transcriptional memory, and HSE1 is also necessary for HSFA2 to bind on APX2 promoter and activate APX2 transcription. The findings will provide important clues for the molecular mechanism of transcriptional memory and will enable engineering of enhanced stress tolerance in crops.}, language = {en} } @phdthesis{Ogden2022, author = {Ogden, Michael}, title = {Uncovering the interplay between nutrient availability and cellulose biosynthesis inhibitor activity}, school = {Universit{\"a}t Potsdam}, pages = {XI, 124}, year = {2022}, abstract = {All plant cells are surrounded by a dynamic, carbohydrate-rich extracellular matrix known as the cell wall. Nutrient availability affects cell wall composition via uncharacterized regulatory mechanisms, and cellulose deficient mutants develop a hypersensitive root response to growth on high concentrations of nitrate. Since cell walls account for the bulk of plant biomass, it is important to understand how nutrients regulate cell walls. This could provide important knowledge for directing fertilizer treatments and engineering plants with higher nutrient use efficiency. The direct effect of nitrate on cell wall synthesis was investigated through growth assays on varying concentrations of nitrate, measuring cellulose content of roots and shoots, and assessing cellulose synthase activity (CESA) using live cell imaging with spinning disk confocal microscopy. A forward genetic screen was developed to isolate mutants impaired in nutrient-mediated cell wall regulation, revealing that cellulose biosynthesis inhibitor (CBI) activity is modulated by nutrient availability. Various non-CESA mutants were isolated that displayed CBI resistance, with the majority of mutations causing perturbation of mitochondria-localized proteins. To investigate mitochondrial involvement, the CBI mechanism of action was investigated using a reverse genetic screen, a targeted pharmacological screen, and -omics approaches. The results generated suggest that CBI-induced cellulose inhibition is due to off-target effects. This provides the groundwork to investigate uncharacterized processes of CESA regulation and adds valuable knowledge to the understanding of CBI activity, which could be harnessed to develop new and improved herbicides.}, language = {en} } @phdthesis{Heidenreich2022, author = {Heidenreich, Anna}, title = {Risk Communicaton of Natural Hazards}, school = {Universit{\"a}t Potsdam}, pages = {XII, 141}, year = {2022}, abstract = {Natural hazards pose a threat to human health and life. In Germany, where the research for this thesis was conducted, numerous weather extremes occurred in the recent past that caused high numbers of fatalities and huge financial losses. The focus of this research is centred around two relevant natural hazards: heat stress and flooding. Preventing negative health impacts and deaths, as well as structural and monetary damage is the purpose of risk management and this requires citizens to adapt as well. Risk communication is implemented to foster people's risk perception and motivate individual adaptation. However, methods of risk and crisis communication are often not evaluated in a structured manner. Much interdisciplinary research exists on both risk perception and adaptation, however, not much is known on the connection between the two. Furthermore, the existing research on risk communication is often not theory-driven and its impact on individual adaptation and risk perception is not thoroughly documented. This dissertation follows three research aims: (1) Compare psychological theories that contribute to natural hazard research. (2) Explore risk perception and adaptive behaviour by applying multiple methods. And (3) evaluate one risk communication method and one crisis communication method in a theory-driven manner to determine their impact on risk perception and adaptive behaviour. First, a literature review is provided on existing psychological theories which aim to explain the behaviour of individuals with regards to natural hazards. The three key theories included are the Protection Motivation Theory (PMT), the Protective Action Decision Model (PADM), and the Risk Information Seeking and Processing Model (RISP). Each of these are described and compared to each other with a focus on their explanatory power and practical significance in interdisciplinary research. Theoretical adaptations and possible extensions for future research are proposed for the presented approaches. Second, a multimethod field study on heat stress at an open-air event is presented. Face-to-face surveys (n = 306) and behavioural observations (n = 2750) were carried out at a horticultural show in W{\"u}rzburg in summer 2018. The visitors' risk perception, adaptive behaviour, and activity level were analysed and compared between hot days, summer days, and rainy days, applying correlation analyses, ANOVA, and multiple regression analyses. Heat risk perception was generally high, but most respondents were unaware of heat warnings on the day of their visit. During hot days the highest level of adaptation and lower activity levels were observed. Discrepancies between reported and observed adaptation emerged for different age groups.. Third, a telephone and web-based household survey on heat stress was conducted in the cities of W{\"u}rzburg, Potsdam, and Remscheid in 2019 (n = 1417). The PADM served as the study's theoretical framework. In multiple regression analyses the PADM factors of environmental and demographic context, risk communication, and psychological processes explained a substantial share of variance of protection motivation, protective response, and emotion-focused coping. Elements of crisis communication of a heat warning were evaluated experimentally. Results showed that understanding and adaptation intention was significantly higher in individuals that had received action recommendations alongside the heat warning. Fourth, the focus is set on a risk communication method of the flood context. A series of workshops on individual flood protection was carried out in six different settings. The participants (n = 115) answered a pretest-posttest questionnaire. Mixed-model analyses revealed significant increases in self-efficacy, subjective knowledge, and protection motivation. Stronger effects were observed in younger participants and those with lower levels of previous knowledge on flood adaptation as well as no flood experience. The findings of this thesis help to understand individual adaptation, as well as possible impacts of risk and crisis communication on risk perception and adaptation. The scientific background of this work is rooted in the disciplines of psychology and geosciences. The two theories PMT and PADM proved to be useful theoretical frameworks for the presented studies to suggest improvements in risk communication methods. A broad picture of individual adaptation is captured through a variety of methods of self-reports (face-to-face, telephone-based, web-based, and paper-pencil surveys) and behavioural observations, which recorded past and intended behaviour. Alongside with further methodological recommendations, the theory-driven evaluations of risk and crisis communication methods can serve as best-practice examples for future evaluation studies in natural hazard research but also other sciences dealing with risk behaviour to identify and improve effective risk communication pathways.}, language = {en} } @phdthesis{Schoenfeldt2022, author = {Sch{\"o}nfeldt, Elisabeth}, title = {Giant landslides in Patagonia, Argentina}, pages = {XXII, 156}, year = {2022}, language = {en} } @phdthesis{YilmazWoerfel2022, author = {Yilmaz W{\"o}rfel, Seda}, title = {Adverbial Relations in Turkish-German Bilingualism}, series = {Mehrsprachigkeit = Multilingualism}, journal = {Mehrsprachigkeit = Multilingualism}, number = {53}, publisher = {Waxmann}, address = {M{\"u}nster}, isbn = {978-3-8309-4542-0}, issn = {1433-0792}, pages = {265}, year = {2022}, abstract = {The Turkish language in diaspora is in process of change due to different language constellations of immigrants and the dominance of majority languages. This led to a great interest in various research areas, particularly in linguistics. Against this background, this study focuses on developmental change in the use of adverbial clause-combining constructions in Turkish-German bilingual students' oral and written text production. It illustrates the use of non-finite constructions and some unique alternative strategies to express adverbial relations with authentic examples in Turkish and German. The findings contribute to a better understanding of how bilingual competencies vary in expressing adverbial relations depending on language contact and extra-linguistic factors.}, language = {en} } @phdthesis{Teetz2022, author = {Teetz, Tim}, title = {Work design and leadership in lean production}, school = {Universit{\"a}t Potsdam}, pages = {138}, year = {2022}, language = {en} } @phdthesis{Nguyen2022, author = {Nguyen, Van Thanh}, title = {Unravelling the mysteries of the Annamites}, school = {Universit{\"a}t Potsdam}, pages = {116}, year = {2022}, abstract = {The Annamites mountain range of Southeast Asia which runs along the border of Viet Nam and Laos is an important biodiversity hotspot with high levels of endemism. However, that biodiversity is threatened by unsustainable hunting, and many protected areas across the region have been emptied of their wildlife. To better protect the unique species in the Annamites, it is crucial to have a better understanding of their ecology and distribution. Additionally, basic genetic information is needed to provide conservation stakeholders with essential information to facilitate conservation breeding and counteract the illegal wildlife trade. To date, this baseline information is lacking for many Annamites species. This thesis aims to assess the effectiveness of using non-invasive collection methods, i.e. camera-trap surveys and leech-derived wildlife host DNA, in order to improve and enhance our understanding of ecology, distribution, and genetic diversity of the Annamites terrestrial mammals. In chapter 1, we analysed data from a systematic landscape camera-trap survey using single-species occupancy models to assess the ecology and distribution of two little-known Annamite endemics, the Annamite dark muntjac (Muntiacus rooseveltorum / truongsonensis) and Annamite striped rabbit (Nesolagus timminsi), in multiple protected areas across the Annamites. This chapter provided the first in-depth information on their ecology, as well as distribution patterns at large spatial scales. Most notably, we found that the Annamite dark muntjac was predominantly found at higher elevations, while responses to elevation varied among study areas for the Annamite striped rabbit. We estimated occupancy probabilities for both endemics by using their responses to environmental and anthropogenic influences and used this information to make recommendations for targeted conservation actions. We discuss how the approach we used for these two Annamites endemics can be expanded for other little-known and threatened species in other tropical regions. As is the case with ecology and distribution, very little is known about the genetic diversity of the Annamite striped rabbit and other mammals of the Annamites. This poor understanding is mainly attributed to the lack of a comprehensive DNA sample collection that covers the species' entire distribution range, which is believed to be a consequence of the low density of mammals or the remoteness of species' habitat. In order to overcome the difficulties when trying to collect DNA samples from elusive mammals, we applied invertebrate-derived DNA (iDNA) sampling via hematophagous leeches to indirectly obtain genetic materials of their terrestrial host mammals. In chapter 2, leech-derived DNA was used to study the genetic diversity of the Annamite striped rabbit population. By analysing the DNA extracted from leech samples collected at multiple study areas of the central Annamites, we found a genetic variation with five haplotypes among nine obtained sequences. Despite this diversity, we found no clear phylogeographic pattern among the lagomorph's populations in central Annamites. The findings have direct conservation implications for the species, as local stakeholders are currently establishing a conservation rescue and breeding facility for Annamite endemic species. Thus our results suggested that Annamite striped rabbits from multiple protected areas in central Annamites can be used as founders for the breeding program. In chapter 3, the genetic material of six mammals, which are frequently found in Indochina's illegal wildlife trade, was extracted from leeches collected at six study sites across the Anamites. Species-specific genetic markers were used to obtain DNA fragments that were analysed together with Genbank reference sequences from other parts of the species' distribution range. Our results showed that invertebrate-derived DNA can be used to fill the sampling gaps and provide genetic reference data that is needed for conservation breeding programmes or to counteract the illegal wildlife trade. Overal, this dissertation provides the first insights in the ecology, distribution, and genetics of rare and threatened species of the Annamites by utilising camera traps and leech-derived DNA as two non-invasive collection methods. This information is essential for improving conservation efforts of local stakeholders and managers, especially for the Annamite endemics. Results in this dissertation also show the effectiveness of both non-invasive methods for studying terrestrial mammals at a landscape level. By expanding the application of these methods to other protected areas across the Annamites, we will further our understanding of ecology, distribution, and genetics of Annamite endemics. With such landscape-scale surveys, we are able to provide stakeholders with an overview of the current status of wildlife in the Annamites which supports efforts to protect these secretive species from illegal hunting and thus their extinction.}, language = {en} } @phdthesis{Vyse2022, author = {Vyse, Kora}, title = {Elucidating molecular determinants of the loss of freezing tolerance during deacclimation after cold priming and low temperature memory after triggering}, school = {Universit{\"a}t Potsdam}, pages = {vii, 147}, year = {2022}, abstract = {W{\"a}hrend ihrer Entwicklung m{\"u}ssen sich Pflanzen an Temperaturschwankungen anpassen. Niedrige Temperaturen {\"u}ber dem Gefrierpunkt induzieren in Pflanzen eine K{\"a}lteakklimatisierung und h{\"o}here Frosttoleranz, die sich bei w{\"a}rmeren Temperaturen durch Deakklimatisierung wieder zur{\"u}ckbildet. Der Wechsel zwischen diesen beiden Prozessen ist f{\"u}r Pflanzen unerl{\"a}sslich, um als Reaktion auf unterschiedliche Temperaturbedingungen eine optimale Fitness zu erreichen. Die K{\"a}lteakklimatisierung ist umfassend untersucht worden,{\"u}ber die Regulierung der Deakklimatisierung ist jedoch wenig bekannt. In dieser Arbeit wird der Prozess der Deakklimatisierung auf physiologischer und molekularer Ebene in Arabidopsis thaliana untersucht. Messungen des Elektrolytverlustes w{\"a}hrend der K{\"a}lteakklimatisierung und bis zu vier Tagen nach Deakklimatisierung erm{\"o}glichten die Identifizierung von vier Knockout-Mutanten (hra1, lbd41, mbf1c und jub1), die im Vergleich zum Wildtyp eine langsamere Deakklimatisierungsrate aufwiesen. Eine transkriptomische Studie mit Hilfe von RNA-Sequenzierung von A. thaliana Col-0, jub1 und mbf1c zeigte die Bedeutung der Hemmung von stressreaktiven und Jasmonat-ZIM-Dom{\"a}nen-Genen sowie die Regulierung von Zellwandmodifikationen w{\"a}hrend der Deakklimatisierung. Dar{\"u}ber hinaus zeigten Messungen der Alkoholdehydrogenase Aktivit{\"a}t und der Genexpressions{\"a}nderungen von Hypoxiemarkern w{\"a}hrend der ersten vier Tagen der Deakklimatisierung, dass eine Hypoxie-Reaktion w{\"a}hrend der Deakklimatisierung aktiviert wird. Es wurde gezeigt, dass die epigenetische Regulierung w{\"a}hrend der K{\"a}lteakklimatisierung und der 24-st{\"u}ndigen Deakklimatisierung in A. thaliana eine große Rolle spielt. Dar{\"u}ber hinaus zeigten beide Deakklimatisierungsstudien, dass die fr{\"u}here Hypothese, dass Hitzestress eine Rolle bei der fr{\"u}hen Deakklimatisierung spielen k{\"o}nnte, unwahrscheinlich ist. Eine Reihe von DNA- und Histondemethylasen sowie Histonvarianten wurden w{\"a}hrend der Deakklimatisierung hochreguliert, was auf eine Rolle im pflanzlichen Ged{\"a}chtnis schließen l{\"a}sst. In j{\"u}ngster Zeit haben mehrere Studien gezeigt, dass Pflanzen in der Lage sind, die Erinnerung an einen vorangegangenen K{\"a}ltestress auch nach einer Woche Deakklimatisierung zu bewahren. In dieser Arbeit ergaben Transkriptom- und Metabolomanalysen von Arabidopsis w{\"a}hrend 24 Stunden Priming (K{\"a}lteakklimatisierung) und Triggering (wiederkehrender K{\"a}ltestress nach Deakklimatisierung) eine unikale signifikante und vor{\"u}bergehende Induktion der Transkriptionsfaktoren DREB1D, DREB1E und DREB1F w{\"a}hrend des Triggerings, die zur Feinabstimmung der zweiten K{\"a}ltestressreaktion beitr{\"a}gt. Dar{\"u}ber hinaus wurden Gene, die f{\"u}r Late Embryogenesis Abundant (LEA) und Frostschutzproteine kodieren, sowie Proteine, die reaktive Sauerstoffspezies entgiften, w{\"a}hrend des sp{\"a}ten Triggerings (24 Stunden) st{\"a}rker induziert als nach dem ersten K{\"a}lteimpuls, w{\"a}hrend Xyloglucan- Endotransglucosylase/Hydrolase Gene, deren Produkte f{\"u}r eine Restrukturierung der Zellwand verantwortlich sind, fr{\"u}h auf das Triggering reagierten. Die starke Induktion dieser Gene, sowohl bei der Deakklimatisierung als auch beim Triggering, l{\"a}sst vermuten, dass sie eine wesentliche Rolle bei der Stabilisierung der Zellen w{\"a}hrend des Wachstums und bei der Reaktion auf wiederkehrende Stressbedingungen spielen. Zusammenfassend gibt diese Arbeit neue Einblicke in die Regulierung der Deakklimatisierung und des K{\"a}ltestress-Ged{\"a}chtnisses in A. thaliana und er{\"o}ffnet neue M{\"o}glichkeiten f{\"u}r k{\"u}nftige, gezielte Studien von essentiellen Genen in diesem Prozess.}, language = {en} } @phdthesis{Heinzel2021, author = {Heinzel, Mirko Noa}, title = {World Bank staff and project implementation}, year = {2021}, language = {en} } @phdthesis{Mulamustafic2022, author = {Mulamustafic, Adem}, title = {The Clash of the Images}, series = {Theoria ; 3}, journal = {Theoria ; 3}, publisher = {Schwabe Verlag}, address = {Berlin}, isbn = {978-3-7574-0065-1}, doi = {10.25932/publishup-55816}, school = {Universit{\"a}t Potsdam}, pages = {212}, year = {2022}, abstract = {In everyday life, we take there to be ordinary objects such as persons, tables, and stones bearing certain properties such as color and shape and standing in various causal relationships to each other. Basic convictions such as these form our everyday picture of the world: the manifest image. The scientific image, on the other hand, is a system of beliefs that is only based on scientific results. It contains many beliefs that are not contained in the manifest image. At first glance, this may not seem to be a problem. But Mulamustafi? shows convincingly that this is a mistake: The world as it is in itself cannot be both the way the manifest image depicts it and the way the scientific image describes it to be. Adem Mulamustafic studied and completed his PhD in philosophy at the University of Potsdam. His areas of specialization are metaphysics, philosophy of science, and critical thinking.}, language = {en} } @phdthesis{Uflewski2021, author = {Uflewski, Michal}, title = {Characterizing the regulation of proton antiport across the thylakoid membrane}, school = {Universit{\"a}t Potsdam}, pages = {122}, year = {2021}, abstract = {Die Energie, die zum Antrieb photochemischer Reaktionen ben{\"o}tigt wird, stammt aus der Ladungstrennung an der Thylakoidmembran. Aufrgrund des Unterschieds in der Protonenkonzentration zwischen dem Stroma der Chloroplasten und dem Thylakoidlumen wird eine Protonenmotorische Kraft (pmf) erzeugt. Die pmf setzt sich aus dem Protonengradienten (ΔpH) und dem Membranpotential (ΔΨ) zusammen, die gemeinsam die ATP-Synthese antreiben. In der Natur schwankt die Energiemenge, die die Photosynthese antreibt, aufgrund h{\"a}ufiger {\"A}nderungen der Lichtintensit{\"a}t. Der Thylakoid-Ionentransport kann den Energiefluss durch einen Photosyntheseapparat an die Lichtverf{\"u}gbarkeit anpassen, indem er die pmf-Zusammensetzung ver{\"a}ndert. Die Dissipation von ΔΨ verringert die Ladungsrekombination am Photosystem II, so dass ein Anstieg der ΔpH-Komponente eine R{\"u}ckkopplung zur Herabregulierung der Photosynthese ausl{\"o}sen kann. Der durch den K+-Austausch-Antiporter 3 (KEA3) gesteuerte K+/H+-Antiport reduziert den ΔpH-Anteil von pmf und d{\"a}mpft dadurch das nicht-photochemische Quenching (NPQ). Infolgedessen erh{\"o}ht sich die Photosyntheseeffizienz beim {\"U}bergang zu geringerer Lichtintensit{\"a}t. Ziel dieser Arbeit war es, Antworten auf Fragen zur Regulierung der KEA3-Aktivit{\"a}t und ihrer Rolle in der Pflanzenentwicklung zu finden. Die vorgestellten Daten zeigen, dass KEA3 in Pflanzen, denen der Chloroplasten-ATP-Synthase-Assembly-Faktor CGL160 fehlt und die eine verminderte ATP-Synthase-Aktivit{\"a}t aufweisen, eine zentrale Rolle bei der Regulierung der Photosynthese und des Pflanzenwachstums unter station{\"a}ren Bedingungen spielt. Das Fehlen von KEA3 in der cgl160-Mutante f{\"u}hrt zu einer starken Beeintr{\"a}chtigung des Wachstums, da die Photosynthese aufgrund des erh{\"o}hten pH-abh{\"a}ngigen NPQs und des verringerten Elektronenflusses durch den Cytochrom b6f-Komplex eingeschr{\"a}nkt ist. Die {\"U}berexpression von KEA3 in der cgl160-Mutante erh{\"o}ht die Ladungsrekombination im Photosystem II und f{\"o}rdert die Photosynthese. In Zeiten geringer ATP-Synthase-Aktivit{\"a}t profitieren die Pflanzen also von der KEA3-Aktivit{\"a}t. KEA3 unterliegt einer Dimerisierung {\"u}ber seinen regulatorischen C-Terminus (RCT). Der RCT reagiert auf Ver{\"a}nderungen der Lichtintensit{\"a}t, da die Pflanzen, die KEA3 ohne diese Dom{\"a}ne exprimieren, einen reduzierten Lichtschutzmechanismus bei Lichtintensit{\"a}tsschwankungen aufweisen. Allerdings fixieren diese Pflanzen w{\"a}hrend der Photosynthese-Induktionsphase mehr Kohlenstoff als Gegenleistung f{\"u}r einen langfristigen Photoprotektor, was die regulierende Rolle von KEA3 in der Pflanzenentwicklung zeigt. Der KEA3-RCT ist dem Thylakoidstroma zugewandt, so dass seine Regulierung von lichtinduzierten Ver{\"a}nderungen in der Stroma-Umgebung abh{\"a}ngt. Die Regulierung der KEA3-Aktivit{\"a}t {\"u}berschneidet sich mit den pH-{\"A}nderungen im Stroma, die bei Lichtschwankungen auftreten. Es hat sich gezeigt, dass ATP und ADP eine Affinit{\"a}t zum heterolog exprimierten KEA3 RCT haben. Eine solche Wechselwirkung verursacht Konformations{\"a}nderungen in der RCT-Struktur. Die Faltung der RCT-Liganden-Interaktion h{\"a}ngt vom pH-Wert der Umgebung ab. Mit einer Kombination aus Bioinformatik und In-vitro-Ansatz wurde die ATP-Bindungsstelle am RCT lokalisiert. Das Einf{\"u}gen einer Punktmutation in der KEA3-RCT Bindungsstelle in planta f{\"u}hrte zu einer Deregulierung der Antiporteraktivit{\"a}t beim {\"U}bergang zu wenig Licht. Die in dieser Arbeit vorgestellten Daten erm{\"o}glichten es uns, die Rolle von KEA3 bei der Anpassung der Photosynthese umfassender zu bewerten und Modelle zur Regulierung der KEA3-Aktivit{\"a}t w{\"a}hrend des {\"U}bergangs zwischen verschiedenen Lichtintensit{\"a}ten vorzuschlagen.}, language = {en} }