TY  - GEN
A1  - Zurell, Damaris
A1  - König, Christian
A1  - Malchow, Anne-Kathleen
A1  - Kapitza, Simon
A1  - Bocedi, Greta
A1  - Travis, Justin M. J.
A1  - Fandos, Guillermo
T1  - Spatially explicit models for decision-making in animal conservation and restoration
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Models are useful tools for understanding and predicting ecological patterns and processes. Under ongoing climate and biodiversity change, they can greatly facilitate decision-making in conservation and restoration and help designing adequate management strategies for an uncertain future. Here, we review the use of spatially explicit models for decision support and to identify key gaps in current modelling in conservation and restoration. Of 650 reviewed publications, 217 publications had a clear management application and were included in our quantitative analyses. Overall, modelling studies were biased towards static models (79%), towards the species and population level (80%) and towards conservation (rather than restoration) applications (71%). Correlative niche models were the most widely used model type. Dynamic models as well as the gene-to-individual level and the community-to-ecosystem level were underrepresented, and explicit cost optimisation approaches were only used in 10% of the studies. We present a new model typology for selecting models for animal conservation and restoration, characterising model types according to organisational levels, biological processes of interest and desired management applications. This typology will help to more closely link models to management goals. Additionally, future efforts need to overcome important challenges related to data integration, model integration and decision-making. We conclude with five key recommendations, suggesting that wider usage of spatially explicit models for decision support can be achieved by 1) developing a toolbox with multiple, easier-to-use methods, 2) improving calibration and validation of dynamic modelling approaches and 3) developing best-practise guidelines for applying these models. Further, more robust decision-making can be achieved by 4) combining multiple modelling approaches to assess uncertainty, and 5) placing models at the core of adaptive management. These efforts must be accompanied by long-term funding for modelling and monitoring, and improved communication between research and practise to ensure optimal conservation and restoration outcomes.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1243 
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-549915
SN  - 1866-8372
VL  - 2022
SP  - 1
EP  - 16
PB  - Universitätsverlag Potsdam
CY  - Potsdam
ET  - 4
ER  - 
TY  - JOUR
A1  - Zimmermann, Heike
A1  - Stoof-Leichsenring, Kathleen R.
A1  - Kruse, Stefan
A1  - Nürnberg, Dirk
A1  - Tiedemann, Ralf
A1  - Herzschuh, Ulrike
T1  - Sedimentary ancient DNA from the subarctic North Pacific
BT  - How sea ice, salinity, and insolation dynamics have shaped diatom composition and richness over the past 20,000 years
JF  - Paleoceanography and paleoclimatology
N2  - We traced diatom composition and diversity through time using diatom-derived sedimentary ancient DNA (sedaDNA) from eastern continental slope sediments off Kamchatka (North Pacific) by applying a short, diatom-specific marker on 63 samples in a DNA metabarcoding approach. The sequences were assigned to diatoms that are common in the area and characteristic of cold water. SedaDNA allowed us to observe shifts of potential lineages from species of the genus Chaetoceros that can be related to different climatic phases, suggesting that pre-adapted ecotypes might have played a role in the long-term success of species in areas of changing environmental conditions. These sedaDNA results complement our understanding of the long-term history of diatom assemblages and their general relationship to environmental conditions of the past. Sea-ice diatoms (Pauliella taeniata [Grunow] Round & Basson, Attheya septentrionalis [ostrup] R. M. Crawford and Nitzschia frigida [Grunow]) detected during the late glacial and Younger Dryas are in agreement with previous sea-ice reconstructions. A positive correlation between pennate diatom richness and the sea-ice proxy IP25 suggests that sea ice fosters pennate diatom richness, whereas a negative correlation with June insolation and temperature points to unfavorable conditions during the Holocene. A sharp increase in proportions of freshwater diatoms at similar to 11.1 cal kyr BP implies the influence of terrestrial runoff and coincides with the loss of 42% of diatom sequence variants. We assume that reduced salinity at this time stabilized vertical stratification which limited the replenishment of nutrients in the euphotic zone.
KW  - Bacillariophyceae
KW  - DNA metabarcoding
KW  - glacial / interglacial transition
KW  - northwestern Pacific
KW  - richness
KW  - sedaDNA
Y1  - 2021
U6  - https://doi.org/10.1029/2020PA004091
SN  - 2572-4525
VL  - 36
IS  - 4
PB  - Wiley
CY  - Hoboken, NJ
ER  - 
TY  - JOUR
A1  - Zhang, Xiaorong
A1  - Caserta, Giorgio
A1  - Yarman, Aysu
A1  - Supala, Eszter
A1  - Tadjoung Waffo, Armel Franklin
A1  - Wollenberger, Ulla
A1  - Gyurcsanyi, Robert E.
A1  - Zebger, Ingo
A1  - Scheller, Frieder W.
T1  - "Out of Pocket" protein binding
BT  - a dilemma of epitope imprinted polymers revealed for human hemoglobin
JF  - Chemosensors
N2  - The epitope imprinting approach applies exposed peptides as templates to synthesize Molecularly Imprinted Polymers (MIPs) for the recognition of the parent protein. While generally the template protein binding to such MIPs is considered to occur via the epitope-shaped cavities, unspecific interactions of the analyte with non-imprinted polymer as well as the detection method used may add to the complexity and interpretation of the target rebinding. To get new insights on the effects governing the rebinding of analytes, we electrosynthesized two epitope-imprinted polymers using the N-terminal pentapeptide VHLTP-amide of human hemoglobin (HbA) as the template. MIPs were prepared either by single-step electrosynthesis of scopoletin/pentapeptide mixtures or electropolymerization was performed after chemisorption of the cysteine extended VHLTP peptide. Rebinding of the target peptide and the parent HbA protein to the MIP nanofilms was quantified by square wave voltammetry using a redox probe gating, surface enhanced infrared absorption spectroscopy, and atomic force microscopy. While binding of the pentapeptide shows large influence of the amino acid sequence, all three methods revealed strong non-specific binding of HbA to both polyscopoletin-based MIPs with even higher affinities than the target peptides.
KW  - Molecularly Imprinted Polymers
KW  - epitope imprinting
KW  - non-specific
KW  - binding
KW  - redox gating
KW  - SEIRA spectroelectrochemistry
Y1  - 2021
U6  - https://doi.org/10.3390/chemosensors9060128
SN  - 2227-9040
VL  - 9
IS  - 6
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Yildiz, Tugba
A1  - Leimkühler, Silke
T1  - TusA is a versatile protein that links translation efficiency to cell division in Escherichia coli
JF  - Journal of bacteriology
N2  - To enable accurate and efficient translation, sulfur modifications are introduced posttranscriptionally into nucleosides in tRNAs. The biosynthesis of tRNA sulfur modifications involves unique sulfur trafficking systems for the incorporation of sulfur atoms in different nucleosides of tRNA. One of the proteins that is involved in inserting the sulfur for 5-methylaminomethyl-2-thiouridine (mnm(5)s(2)U34) modifications in tRNAs is the TusA protein. TusA, however, is a versatile protein that is also involved in numerous other cellular pathways. Despite its role as a sulfur transfer protein for the 2-thiouridine formation in tRNA, a fundamental role of TusA in the general physiology of Escherichia coli has also been discovered. Poor viability, a defect in cell division, and a filamentous cell morphology have been described previously for tusA-deficient cells. In this report, we aimed to dissect the role of TusA for cell viability. We were able to show that the lack of the thiolation status of wobble uridine (U-34) nucleotides present on Lys, Gln, or Glu in tRNAs has a major consequence on the translation efficiency of proteins; among the affected targets are the proteins RpoS and Fis. Both proteins are major regulatory factors, and the deregulation of their abundance consequently has a major effect on the cellular regulatory network, with one consequence being a defect in cell division by regulating the FtsZ ring formation. <br /> IMPORTANCE More than 100 different modifications are found in RNAs. One of these modifications is the mnm(5)s(2)U modification at the wobble position 34 of tRNAs for Lys, Gln, and Glu. The functional significance of U34 modifications is substantial since it restricts the conformational flexibility of the anticodon, thus providing translational fidelity. We show that in an Escherichia coli TusA mutant strain, involved in sulfur transfer for the mnm(5)s(2)U34 thio modifications, the translation efficiency of RpoS and Fis, two major cellular regulatory proteins, is altered. Therefore, in addition to the transcriptional regulation and the factors that influence protein stability, tRNA modifications that ensure the translational efficiency provide an additional crucial regulatory factor for protein synthesis.
KW  - iron-sulfur clusters
KW  - tRNA thio modifications
KW  - FtsZ ring formation
KW  - cell
KW  - division
KW  - TusA
KW  - RpoS
KW  - Fis
KW  - FtsZ
Y1  - 2021
U6  - https://doi.org/10.1128/JB.00659-20
SN  - 1098-5530
VL  - 203
IS  - 7
PB  - American Society for Microbiology
CY  - Washington
ER  - 
TY  - JOUR
A1  - Yarman, Aysu
A1  - Kurbanoğlu, Sevinç
A1  - Zebger, Ingo
A1  - Scheller, Frieder W.
T1  - Simple and robust
BT  - the claims of protein sensing by molecularly imprinted polymers
JF  - Sensors and actuators : B, Chemical : an international journal devoted to research and development of chemical transducers
N2  - A spectrum of 7562 publications on Molecularly Imprinted Polymers (MIPs) has been presented in literature within the last ten years (Scopus, September 7, 2020). Around 10 % of the papers published on MIPs describe the recognition of proteins. The straightforward synthesis of MIPs is a significant advantage as compared with the preparation of enzymes or antibodies. MIPs have been synthesized from only one up to six functional monomers while proteins are made up of 20 natural amino acids. Furthermore, they can be synthesized against structures of low immunogenicity and allow multi-analyte measurements via multi-target synthesis. Electrochemical methods allow simple polymer synthesis, removal of the template and readout. Among the different sensor configurations electrochemical MIP-sensors provide the broadest spectrum of protein analytes. The sensitivity of MIP-sensors is sufficiently high for biomarkers in the sub-nanomolar region, nevertheless the cross-reactivity of highly abundant proteins in human serum is still a challenge. MIPs for proteins offer innovative tools not only for clinical and environmental analysis, but also for bioimaging, therapy and protein engineering.
KW  - Molecularly imprinted polymer
KW  - Plastibodies
KW  - Functional scaffolds
KW  - Biomimetic sensors
KW  - Proteins
Y1  - 2021
U6  - https://doi.org/10.1016/j.snb.2020.129369
SN  - 0925-4005
SN  - 1873-3077
VL  - 330
PB  - Elsevier Science
CY  - Amsterdam [u.a.]
ER  - 
TY  - JOUR
A1  - Yan, Jiawei
A1  - Frøkjær, Emil Egede
A1  - Engelbrekt, Christian
A1  - Leimkühler, Silke
A1  - Ulstrup, Jens
A1  - Wollenberger, Ulla
A1  - Xiao, Xinxin
A1  - Zhang, Jingdong
T1  - Voltammetry and single-molecule in situ scanning tunnelling microscopy of the redox metalloenzyme human sulfite oxidase
JF  - ChemElectroChem
N2  - Human sulfite oxidase (hSO) is a homodimeric two-domain enzyme central in the biological sulfur cycle. A pyranopterin molybdenum cofactor (Moco) is the catalytic site and a heme b(5) group located in the N-terminal domain. The two domains are connected by a flexible linker region. Electrons produced at the Moco in sulfite oxidation, are relayed via heme b(5) to electron acceptors or an electrode surface. Inter-domain conformational changes between an open and a closed enzyme conformation, allowing "gated" electron transfer has been suggested. We first recorded cyclic voltammetry (CV) of hSO on single-crystal Au(111)-electrode surfaces modified by self-assembled monolayers (SAMs) both of a short rigid thiol, cysteamine and of a longer structurally flexible thiol, omega-amino-octanethiol (AOT). hSO on cysteamine SAMs displays a well-defined pair of voltammetric peaks around -0.207 V vs. SCE in the absence of sulfite substrate, but no electrocatalysis. hSO on AOT SAMs displays well-defined electrocatalysis, but only "fair" quality voltammetry in the absence of sulfite. We recorded next in situ scanning tunnelling spectroscopy (STS) of hSO on AOT modified Au(111)-electrodes, disclosing, a 2-5 % surface coverage of strong molecular scale contrasts, assigned to single hSO molecules, notably with no contrast difference in the absence and presence of sulfite. In situ STS corroborated this observation with a sigmoidal tunnelling current/overpotential correlation.
KW  - cyclic voltammetry
KW  - human sulfite oxidase
KW  - in  situ scanning
KW  - tunnelling spectroscopy
KW  - self-assembled molecular monolayers
KW  - single-crystal gold electrodes
Y1  - 2021
U6  - https://doi.org/10.1002/celc.202001258
SN  - 2196-0216
VL  - 8
IS  - 1
SP  - 164
EP  - 171
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Xu, Xun
A1  - Nie, Yan
A1  - Wang, Weiwei
A1  - Ullah, Imran
A1  - Tung, Wing Tai
A1  - Ma, Nan
A1  - Lendlein, Andreas
T1  - Generation of 2.5D lung bud organoids from human induced pluripotent stem cells
JF  - Clinical hemorheology and microcirculation : blood flow and vessels
N2  - Human induced pluripotent stem cells (hiPSCs) are a promising cell source to generate the patient-specific lung organoid given their superior differentiation potential. However, the current 3D cell culture approach is tedious and time-consuming with a low success rate and high batch-to-batch variability. 

Here, we explored the establishment of lung bud organoids by systematically adjusting the initial confluence levels and homogeneity of cell distribution. 
The efficiency of single cell seeding and clump seeding was compared. Instead of the traditional 3D culture, we established a 2.5D organoid culture to enable the direct monitoring of the internal structure via microscopy. 
It was found that the cell confluence and distribution prior to induction were two key parameters, which strongly affected hiPSC differentiation trajectories. Lung bud organoids with positive expression of NKX 2.1, in a single-cell seeding group with homogeneously distributed hiPSCs at 70% confluence (SC 70% hom) or a clump seeding group with heterogeneously distributed cells at 90% confluence (CL 90% het), can be observed as early as 9 days post induction. 

These results suggest that a successful lung bud organoid formation with single-cell seeding of hiPSCs requires a moderate confluence and homogeneous distribution of cells, while high confluence would be a prominent factor to promote the lung organoid formation when seeding hiPSCs as clumps. 2.5D organoids generated with defined culture conditions could become a simple, efficient, and valuable tool facilitating drug screening, disease modeling and personalized medicine.
KW  - lung organoid
KW  - human induced pluripotent stem cell
KW  - cell culture
Y1  - 2021
U6  - https://doi.org/10.3233/CH-219111
SN  - 1386-0291
SN  - 1875-8622
VL  - 79
IS  - 1
SP  - 217
EP  - 230
PB  - IOS Press
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Xu, Rudan
A1  - Razaghi-Moghadam, Zahra
A1  - Nikoloski, Zoran
T1  - Maximization of non-idle enzymes improves the coverage of the estimated maximal in vivo enzyme catalytic rates in Escherichia coli
JF  - Bioinformatics
N2  - Motivation: 
Constraint-based modeling approaches allow the estimation of maximal in vivo enzyme catalytic rates that can serve as proxies for enzyme turnover numbers. Yet, genome-scale flux profiling remains a challenge in deploying these approaches to catalogue proxies for enzyme catalytic rates across organisms.

Results:
Here, we formulate a constraint-based approach, termed NIDLE-flux, to estimate fluxes at a genome-scale level by using the principle of efficient usage of expressed enzymes. Using proteomics data from Escherichia coli, we show that the fluxes estimated by NIDLE-flux and the existing approaches are in excellent qualitative agreement (Pearson correlation > 0.9). We also find that the maximal in vivo catalytic rates estimated by NIDLE-flux exhibits a Pearson correlation of 0.74 with in vitro enzyme turnover numbers. However, NIDLE-flux results in a 1.4-fold increase in the size of the estimated maximal in vivo catalytic rates in comparison to the contenders. Integration of the maximum in vivo catalytic rates with publically available proteomics and metabolomics data provide a better match to fluxes estimated by NIDLE-flux. Therefore, NIDLE-flux facilitates more effective usage of proteomics data to estimate proxies for kcatomes.
Y1  - 2021
U6  - https://doi.org/10.1093/bioinformatics/btab575
SN  - 1367-4803
SN  - 1460-2059
VL  - 37
IS  - 21
SP  - 3848
EP  - 3855
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - GEN
A1  - Wolff, Martin
A1  - Gast, Klaus
A1  - Evers, Andreas
A1  - Kurz, Michael
A1  - Pfeiffer-Marek, Stefania
A1  - Schüler, Anja
A1  - Seckler, Robert
A1  - Thalhammer, Anja
T1  - A Conserved Hydrophobic Moiety and Helix-Helix Interactions Drive the Self-Assembly of the Incretin Analog Exendin-4
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Exendin-4 is a pharmaceutical peptide used in the control of insulin secretion. Structural information on exendin-4 and related peptides especially on the level of quaternary structure is scarce. We present the first published association equilibria of exendin-4 directly measured by static and dynamic light scattering. We show that exendin-4 oligomerization is pH dependent and that these oligomers are of low compactness. We relate our experimental results to a structural hypothesis to describe molecular details of exendin-4 oligomers. Discussion of the validity of this hypothesis is based on NMR, circular dichroism and fluorescence spectroscopy, and light scattering data on exendin-4 and a set of exendin-4 derived peptides. The essential forces driving oligomerization of exendin-4 are helix–helix interactions and interactions of a conserved hydrophobic moiety. Our structural hypothesis suggests that key interactions of exendin-4 monomers in the experimentally supported trimer take place between a defined helical segment and a hydrophobic triangle constituted by the Phe22 residues of the three monomeric subunits. Our data rationalize that Val19 might function as an anchor in the N-terminus of the interacting helix-region and that Trp25 is partially shielded in the oligomer by C-terminal amino acids of the same monomer. Our structural hypothesis suggests that the Trp25 residues do not interact with each other, but with C-terminal Pro residues of their own monomers.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1161 
KW  - biophysics
KW  - diabetes
KW  - peptides
KW  - oligomerization
KW  - conformational change
KW  - molecular modeling
KW  - static and dynamic light scattering
KW  - spectroscopy
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-522081
SN  - 1866-8372
IS  - 9
ER  - 
TY  - JOUR
A1  - Wolff, Martin
A1  - Gast, Klaus
A1  - Evers, Andreas
A1  - Kurz, Michael
A1  - Pfeiffer-Marek, Stefania
A1  - Schüler, Anja
A1  - Seckler, Robert
A1  - Thalhammer, Anja
T1  - A Conserved Hydrophobic Moiety and Helix-Helix Interactions Drive the Self-Assembly of the Incretin Analog Exendin-4
JF  - Biomolecules
N2  - Exendin-4 is a pharmaceutical peptide used in the control of insulin secretion. Structural information on exendin-4 and related peptides especially on the level of quaternary structure is scarce. We present the first published association equilibria of exendin-4 directly measured by static and dynamic light scattering. We show that exendin-4 oligomerization is pH dependent and that these oligomers are of low compactness. We relate our experimental results to a structural hypothesis to describe molecular details of exendin-4 oligomers. Discussion of the validity of this hypothesis is based on NMR, circular dichroism and fluorescence spectroscopy, and light scattering data on exendin-4 and a set of exendin-4 derived peptides. The essential forces driving oligomerization of exendin-4 are helix–helix interactions and interactions of a conserved hydrophobic moiety. Our structural hypothesis suggests that key interactions of exendin-4 monomers in the experimentally supported trimer take place between a defined helical segment and a hydrophobic triangle constituted by the Phe22 residues of the three monomeric subunits. Our data rationalize that Val19 might function as an anchor in the N-terminus of the interacting helix-region and that Trp25 is partially shielded in the oligomer by C-terminal amino acids of the same monomer. Our structural hypothesis suggests that the Trp25 residues do not interact with each other, but with C-terminal Pro residues of their own monomers.
KW  - biophysics
KW  - diabetes
KW  - peptides
KW  - oligomerization
KW  - conformational change
KW  - molecular modeling
KW  - static and dynamic light scattering
KW  - spectroscopy
Y1  - 2021
U6  - https://doi.org/10.3390/biom11091305
SN  - 2218-273X
VL  - 11
IS  - 9
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Wojcik, Laurie Anne
A1  - Ceulemans, Ruben
A1  - Gaedke, Ursula
T1  - Functional diversity buffers the effects of a pulse perturbation on the dynamics of tritrophic food webs
JF  - Ecology and Evolution
N2  - Biodiversity decline causes a loss of functional diversity, which threatens ecosystems through a dangerous feedback loop: This loss may hamper ecosystems’ ability to buffer environmental changes, leading to further biodiversity losses. In this context, the increasing frequency of human-induced excessive loading of nutrients causes major problems in aquatic systems. Previous studies investigating how functional diversity influences the response of food webs to disturbances have mainly considered systems with at most two functionally diverse trophic levels. We investigated the effects of functional diversity on the robustness, that is, resistance, resilience, and elasticity, using a tritrophic—and thus more realistic—plankton food web model. We compared a non-adaptive food chain with no diversity within the individual trophic levels to a more diverse food web with three adaptive trophic levels. The species fitness differences were balanced through trade-offs between defense/growth rate for prey and selectivity/half-saturation constant for predators. We showed that the resistance, resilience, and elasticity of tritrophic food webs decreased with larger perturbation sizes and depended on the state of the system when the perturbation occurred. Importantly, we found that a more diverse food web was generally more resistant and resilient but its elasticity was context-dependent. Particularly, functional diversity reduced the probability of a regime shift toward a non-desirable alternative state. The basal-intermediate interaction consistently determined the robustness against a nutrient pulse despite the complex influence of the shape and type of the dynamical attractors. This relationship was strongly influenced by the diversity present and the third trophic level. Overall, using a food web model of realistic complexity, this study confirms the destructive potential of the positive feedback loop between biodiversity loss and robustness, by uncovering mechanisms leading to a decrease in resistance, resilience, and potentially elasticity as functional diversity declines.
KW  - functional diversity
KW  - nutrient spike
KW  - pulse perturbation
KW  - regime shift
KW  - robustness
KW  - tritrophic food web
Y1  - 2021
U6  - https://doi.org/10.1002/ece3.8214
SN  - 2045-7758
N1  - Wojcik and Ceulemans shared first authorship.
VL  - 11
IS  - 22
SP  - 15639
EP  - 15663
PB  - John Wiley & Sons, Inc.
CY  - Hoboken (New Jersey)
ER  - 
TY  - GEN
A1  - Wojcik, Laurie Anne
A1  - Ceulemans, Ruben
A1  - Gaedke, Ursula
T1  - Functional diversity buffers the effects of a pulse perturbation on the dynamics of tritrophic food webs
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Biodiversity decline causes a loss of functional diversity, which threatens ecosystems through a dangerous feedback loop: This loss may hamper ecosystems’ ability to buffer environmental changes, leading to further biodiversity losses. In this context, the increasing frequency of human-induced excessive loading of nutrients causes major problems in aquatic systems. Previous studies investigating how functional diversity influences the response of food webs to disturbances have mainly considered systems with at most two functionally diverse trophic levels. We investigated the effects of functional diversity on the robustness, that is, resistance, resilience, and elasticity, using a tritrophic—and thus more realistic—plankton food web model. We compared a non-adaptive food chain with no diversity within the individual trophic levels to a more diverse food web with three adaptive trophic levels. The species fitness differences were balanced through trade-offs between defense/growth rate for prey and selectivity/half-saturation constant for predators. We showed that the resistance, resilience, and elasticity of tritrophic food webs decreased with larger perturbation sizes and depended on the state of the system when the perturbation occurred. Importantly, we found that a more diverse food web was generally more resistant and resilient but its elasticity was context-dependent. Particularly, functional diversity reduced the probability of a regime shift toward a non-desirable alternative state. The basal-intermediate interaction consistently determined the robustness against a nutrient pulse despite the complex influence of the shape and type of the dynamical attractors. This relationship was strongly influenced by the diversity present and the third trophic level. Overall, using a food web model of realistic complexity, this study confirms the destructive potential of the positive feedback loop between biodiversity loss and robustness, by uncovering mechanisms leading to a decrease in resistance, resilience, and potentially elasticity as functional diversity declines.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1251 
KW  - functional diversity
KW  - nutrient spike
KW  - pulse perturbation
KW  - regime shift
KW  - robustness
KW  - tritrophic food web
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-553730
SN  - 1866-8372
N1  - Wojcik and Ceulemans shared first authorship.
IS  - 1251
ER  - 
TY  - THES
A1  - Woehlecke, Sandra
T1  - Das erweiterte Fachwissen für den schulischen Kontext als Leitlinie für eine additive fachliche Lehrveranstaltung im Lehramtsstudium Biologie
T1  - School-related content knowledge as a guideline for an additive subject-based course for preservice biology teachers
N2  - Das Fachwissen von Lehrkräften weist für die Ausprägung fachdidaktischer Expertise eine hohe Bedeutung auf. Welche Merkmale universitäre Lehrveranstaltungen aufweisen sollten, um Lehramtsstudierenden ein berufsspezifisches Fachwissen zu vermitteln, ist jedoch überwiegend noch unklar. 
Innerhalb des Projekts PSI-Potsdam wurde auf theoretischer Grundlage das fachübergreifende Modell des erweiterten Fachwissens für den schulischen Kontext entwickelt. Als Ansatz zur Verbesserung des Biologie-Lehramtsstudiums diente dieses Modell als Konzeptionsgrundlage für eine additive Lehrveranstaltung. Hierbei werden Lerngelegenheiten geboten, um das universitär erworbene Fachwissen über zellbiologische Inhalte auf schulische Kontexte anzuwenden, z.B. durch die Dekonstruktion und anschließende Rekonstruktion von schulischen Lerntexten. Die Wirkung des Seminars wurde in mehreren Zyklen im Forschungsformat der Fachdidaktischen Entwicklungsforschung beforscht. Eine der zentralen Forschungsfragen lautet dabei: Wie kann eine Lerngelegenheit für Lehramtsstudierende der Biologie gestaltet sein, um ein erweitertes Fachwissen für den schulischen Kontext für den zellbiologischen Themenbereich „Struktur und Funktion der Biomembran“ zu fördern?
Anhand fallübergreifender Analysen (n = 29) wird im empirischen Teil aufgezeigt, welche Einstellungen zum Lehramtsstudium in der Stichprobe bestehen. Als ein wichtiges Ergebnis kann hierbei herausgestellt werden, dass sich das Fachinteresse hinsichtlich schulisch und universitär vermittelter Inhalte bei den untersuchten Studierenden auffallend unterscheidet, wobei dem Schulwissen ein deutlich höheres Interesse entgegengebracht wird. Die Berufsrelevanz fachlicher Inhalte wird seitens der Studierenden häufig am Schulwissen festgemacht.
Innerhalb konkreter Einzelfallanalysen (n = 6) wird anhand von Lernpfaden dargestellt, wie sich über mehrere Design-Experimente hinweg fachliche Konzepte entwickelt haben. Bei der Beschreibung wird vor allem auf Schlüsselstellen und Hürden im Lernprozess fokussiert. Aus diesen Ergebnissen folgend werden vorgenommene Iterationen für die einzelnen Zyklen beschrieben, die ebenfalls anhand der iterativen Entwicklung der Design-Prinzipien dargelegt werden. 
Es konnte gezeigt werden, dass die Schlüsselstellen sehr individuell aufgrund der subjektiv fokussierten Inhalte zu Tage treten. Meist treten sie jedoch im Zusammenhang mit der Verknüpfung verschiedener fachlicher Konzepte oder durch kooperative Aufschlüsselungen von Konzepten auf. Fachliche Hürden konnten hingegen in Form von fachlich unangemessenen Vorstellungen fallübergreifend identifiziert werden. Dies betrifft unter anderem die Vorstellung der Biomembran als Wand, die mit den Vorstellungen einer Schutzfunktion und einer formgebenden Funktion der Biomembran einhergeht.
Weiterhin wird beleuchtet, wie das erweiterte Fachwissen für den schulischen Kontext zur Bearbeitung der Lernaufgaben angewendet wurde. Es hat sich gezeigt, dass sich bestimmte Lerngelegenheiten eigenen, um bestimmte Facetten des erweiterten Fachwissens zu fördern. 
Insgesamt scheint das Modell des erweiterten Fachwissens für den schulischen Kontext äußerst geeignet zu sein, um anhand der Facetten und deren Beschreibungen Lerngelegenheiten oder Gestaltungsprinzipien für diese zu konzipieren. Für das untersuchte Lehr-Lernarrangement haben sich kleinere Adaptationen des Modells als sinnvoll erwiesen. Hinsichtlich der Methodologie konnten Ableitungen für die Anwendung der fachdidaktischen Entwicklungsforschung für additive fachliche Lehrveranstaltungen dieser Art herausgestellt werden.
Um den Professionsbezug der fachwissenschaftlichen Anteile im Lehramtsstudium zu verbessern, ist der weitere Einbezug des erweiterten Fachwissens für den schulischen Kontext in die fachwissenschaftlichen Studienanteile überaus wünschenswert.
N2  - The content knowledge of teachers is of great importance for the development of pedagogical content knowledge and its application in teaching. However, the characteristics of university courses in order to provide pre-service biology teachers with job-specific content knowledge are still unclear. Within the project PSI-Potsdam a theory-based interdisciplinary model of school-related content knowledge (SRCK) was developed. This model served as a conceptual basis for an additive course within the biology teacher training curriculum. Learning opportunities are offered to apply the university-acquired subject matter knowledge to school contexts (e.g. through the deconstruction and subsequent reconstruction of texts for school purposes). The effects of the seminar, especially the learning processes, were observed in several cycles in the format of design research. One of the central research questions is: How can a learning opportunity for perspective Biology teachers be designed, to promote SRCK with regard to the topic “structure and function of the biomembrane"? 
Cross-case analyses (n = 29) show existing attitudes towards teacher training. As an important result, it can be emphasized, that the subject interest in school- and university-taught content differs strikingly among the students. School knowledge is shown a significantly higher interest. The professional relevance of subject-related content is often determined by a perceived proximity to school knowledge. 
Within concrete individual case analyses (n = 6), learning paths are used to show how subject-specific concepts have developed over several design experiments. The description focuses primarily on key points and obstacles in the learning process. Within this framework, iterations made for the individual cycles are described. It could be shown that the key points come to light very individually due to the focused content. In most cases, however, they occur in connection with the linking of different concepts or through cooperative explanations of concepts. Obstacles in the learning processes, on the other hand, could be identified across cases in the form of inappropriate ideas. This concerns, among other things, the idea of the biomembrane as a wall, which goes hand in hand with the ideas of a protective function and a shaping function of the biomembrane. Furthermore, a number of possibilities could be shown, how the SRCK was applied in the learning tasks. It was established that certain learning opportunities are appropriate to promote certain facets of SRCK. Overall, the model of SRCK seems to be extremely suitable in order to design learning opportunities. For the investigated teaching-learning arrangement, smaller adaptations of the model have proven as useful. 
In order to improve the professional relevance of the teacher training programme, the further inclusion of the SRCK in the subject-specific study components is highly desirable.
KW  - Professionswissen
KW  - Fachwissen
KW  - Studierendenvorstellungen
KW  - Biomembran
KW  - Erweitertes Fachwissen für den schulischen Kontext
KW  - professional competence
KW  - Design Research
KW  - Design Research
KW  - content knowledge
KW  - biomembrane
KW  - school-related content knowledge
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-521209
ER  - 
TY  - JOUR
A1  - Wendt, Martin
A1  - Senftleben, Nele
A1  - Gros, Patrick
A1  - Schmitt, Thomas
T1  - Coping with environmental extremes
BT  - population ecology and behavioural adaptation of Erebia pronoe, an Alpine butterfly species
JF  - Insects : open access journal
N2  - Simple Summary:& nbsp;High alpine meadows are home to numerous endemic butterfly species. A combination of climate change and changes in agricultural practices has led to a severe decline in many species. A seemingly unaffected representative of this habitat is Erebia pronoe. We studied the behaviour, resource use and population structure of this species to explain its resilience and estimate its future survival potential. This species shows pronounced protandry in combination with serial eclosion. Males were significantly more active and mobile and were also caught significantly more often than females, resulting in a pronounced shift in sex ratio in the predicted population structure. The adults use a wide range of nectar plants and establish homeranges in areas of high habitat quality. Thus, Erebia pronoe adults use a wide array of resources combined with a slight specialisation to avoid niche overlap with closely related species. The resulting ecological flexibility seems to be an adaptation to unpredictable environmental conditions, which should be the result of a long-lasting adaptation process. Moreover, the combination of opportunism and modest specialisation should also be a good basis for coping with future changes caused by climate and land-use change.</p> <br /> <br></p> <br /> A mark-recapture study of the nominotypical Erebia pronoe in the Alps was conducted to survey its ecological demands and characteristics. Population structure analysis revealed a combination of protandry (one-week earlier eclosion of males) and serial eclosion. Significant differences between both sexes were found in population density (males: 580/ha & PLUSMN; 37 SE; females: 241/ha & PLUSMN; 66 SE), sex-ratio (2.4) and behaviour (57.7 vs. 11.9% flying). Both sexes used a wide range of nectar plants (Asteraceae, 77.3%; Dipsacaceae, 12.3%; Gentianaceae, 9.7%). The use of nectar plants shows a non-specific spectrum, which, however, completely avoids overlap with the locally co-occurring species Erebia nivalis. Movement patterns show the establishment of homeranges, which significantly limits the migration potential. Due to its broad ecological niche, E. pronoe will probably be able to react plastically to the consequences of climate change. The formation of high population densities, the unconcerned endangerment status, the unspecific resource spectrum and the sedentary character of the species make E. pronoe a potential indicator of the quality and general resource occurrence of alpine rupicolous grasslands.
KW  - mark-release-recapture
KW  - movement patterns
KW  - opportunistic behaviour
KW  - partial protandry
KW  - population demography
Y1  - 2021
U6  - https://doi.org/10.3390/insects12100896
SN  - 2075-4450
VL  - 12
IS  - 10
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Warmt, Christian
A1  - Fenzel, Carolin Kornelia
A1  - Henkel, Jörg
A1  - Bier, Frank Fabian
T1  - Using Cy5-dUTP labelling of RPA-amplicons with downstream microarray analysis for the detection of antibiotic resistance genes
JF  - Scientific reports
N2  - In this report we describe Cy5-dUTP labelling of recombinase-polymerase-amplification (RPA) products directly during the amplification process for the first time. Nucleic acid amplification techniques, especially polymerase-chain-reaction as well as various isothermal amplification methods such as RPA, becomes a promising tool in the detection of pathogens and target specific genes. Actually, RPA even provides more advantages. This isothermal method got popular in point of care diagnostics because of its speed and sensitivity but requires pre-labelled primer or probes for a following detection of the amplicons. To overcome this disadvantages, we performed an labelling of RPA-amplicons with Cy5-dUTP without the need of pre-labelled primers. The amplification results of various multiple antibiotic resistance genes indicating great potential as a flexible and promising tool with high specific and sensitive detection capabilities of the target genes. After the determination of an appropriate rate of 1% Cy5-dUTP and 99% unlabelled dTTP we were able to detect the bla(CTX-M15) gene in less than 1.6E-03 ng genomic DNA corresponding to approximately 200 cfu of Escherichia coli cells in only 40 min amplification time.
Y1  - 2021
U6  - https://doi.org/10.1038/s41598-021-99774-z
SN  - 2045-2322
VL  - 11
IS  - 1
PB  - Macmillan Publishers Limited, part of Springer Nature
CY  - [London]
ER  - 
TY  - JOUR
A1  - Wang, Meng
A1  - Li, Panpan
A1  - Ma, Yao
A1  - Nie, Xiang
A1  - Grebe, Markus
A1  - Men, Shuzhen
T1  - Membrane sterol composition in Arabidopsis thaliana affects root elongation via auxin biosynthesis
JF  - International journal of molecular sciences
N2  - Plant membrane sterol composition has been reported to affect growth and gravitropism via polar auxin transport and auxin signaling. However, as to whether sterols influence auxin biosynthesis has received little attention. Here, by using the sterol biosynthesis mutant cyclopropylsterol isomerase1-1 (cpi1-1) and sterol application, we reveal that cycloeucalenol, a CPI1 substrate, and sitosterol, an end-product of sterol biosynthesis, antagonistically affect auxin biosynthesis. The short root phenotype of cpi1-1 was associated with a markedly enhanced auxin response in the root tip. Both were neither suppressed by mutations in polar auxin transport (PAT) proteins nor by treatment with a PAT inhibitor and responded to an auxin signaling inhibitor. However, expression of several auxin biosynthesis genes TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1 (TAA1) was upregulated in cpi1-1. Functionally, TAA1 mutation reduced the auxin response in cpi1-1 and partially rescued its short root phenotype. In support of this genetic evidence, application of cycloeucalenol upregulated expression of the auxin responsive reporter DR5:GUS (beta-glucuronidase) and of several auxin biosynthesis genes, while sitosterol repressed their expression. Hence, our combined genetic, pharmacological, and sterol application studies reveal a hitherto unexplored sterol-dependent modulation of auxin biosynthesis during Arabidopsis root elongation.
KW  - Arabidopsis thaliana
KW  - auxin
KW  - auxin biosynthesis
KW  - cycloeucalenol
KW  - CPI1
KW  - sitosterol
KW  - sterol
Y1  - 2021
U6  - https://doi.org/10.3390/ijms22010437
SN  - 1422-0067
VL  - 22
IS  - 1
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Wandt, Viktoria Klara Veronika
A1  - Winkelbeiner, Nicola Lisa
A1  - Bornhorst, Julia
A1  - Witt, Barbara
A1  - Raschke, Stefanie
A1  - Simon, Luise
A1  - Ebert, Franziska
A1  - Kipp, Anna Patricia
A1  - Schwerdtle, Tanja
T1  - A matter of concern
BT  - trace element dyshomeostasis and genomic stability in neurons
JF  - Redox Biology
N2  - Neurons are post-mitotic cells in the brain and their integrity is of central importance to avoid neurodegeneration. Yet, the inability of self-replenishment of post-mitotic cells results in the need to withstand challenges from numerous stressors during life. Neurons are exposed to oxidative stress due to high oxygen consumption during metabolic activity in the brain. Accordingly, DNA damage can occur and accumulate, resulting in genome instability. In this context, imbalances in brain trace element homeostasis are a matter of concern, especially regarding iron, copper, manganese, zinc, and selenium. Although trace elements are essential for brain physiology, excess and deficient conditions are considered to impair neuronal maintenance. Besides increasing oxidative stress, DNA damage response and repair of oxidative DNA damage are affected by trace elements. Hence, a balanced trace element homeostasis is of particular importance to safeguard neuronal genome integrity and prevent neuronal loss. This review summarises the current state of knowledge on the impact of deficient, as well as excessive iron, copper, manganese, zinc, and selenium levels on neuronal genome stability
Y1  - 2021
U6  - https://doi.org/10.1016/j.redox.2021.101877
VL  - 41
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - THES
A1  - Verbancic, Jana
T1  - Carbon supply and the regulation of primary cell wall synthesis in Arabidopsis thaliana
N2  - Cellulose is the most abundant biopolymer on Earth and cell wall (CW) synthesis is one of the major carbon consumers in the plant cell. Structure and several interaction partners of plasma membrane (PM)-bound cellulose synthase (CESA) complexes, CSCs, have been studied extensively, but much less is understood about the signals that activate and translocate CESAs to the PM and how exactly cellulose synthesis is being regulated during the diel cycle. The literature describes CSC regulation possibilities through interactions with accessory proteins upon stress conditions (e.g. CC1), post-translational modifications that regulate CSC speed and their possible anchoring in the PM (e.g. with phosphorylation and S-acylation, respectively). In this thesis, 13CO2 labeling and imaging techniques were employed in the same Arabidopsis seedling growth system to elucidate how and when new carbon is incorporated into cell wall (CW) sugars and UDP-glucose, and to follow CSC behavior during the diel cycle. Additionally, an ubiquitination analysis was performed to investigate a possible mechanism to affect CSC trafficking to and/or from the PM. Carbon is being incorporated into CW glucose at a 3-fold higher rate during the light period in comparison to the night in wild-type seedlings. Furthermore, CSC density at the PM, as an indication of active cellulose synthesizing machinery, is increasing in the light and falling during the night, showing that CW biosynthesis is more active in the light. Therefore, CW synthesis might be regulated by the carbon status of the cell. This regulation is broken in the starchless pgm mutant where light and dark carbon incorporation rates into CW glucose are similar, possibly due to the high soluble sugar content in pgm during the first part of the night. Strikingly, pgm CSC abundance at the PM is constantly low during the whole diel cycle, indicating little or no cellulose synthesis, but can be restored with exogenous sucrose or a longer photoperiod. Ubiquitination was explored as a possible regulating mechanism for translocation of primary CW CSCs from the PM and several potential ubiquitination sites have been identified.. The approach in this thesis enabled to study cellulose/CW synthesis from different angles but in the same growth system, allowing direct comparison of those methodologies, which could help understand the relationship between the amount of available carbon in a plant cell and the cells capacity to synthesize cellulose/CW. Understanding which factors contribute to cellulose synthesis regulation and addressing those fundamental questions can provide essential knowledge to manage the need for increased crop production.
KW  - cellulose
KW  - cell wall
KW  - 13CO2 labeling
KW  - UDP-glucose
KW  - ubiquitination
Y1  - 2021
ER  - 
TY  - THES
A1  - Uflewski, Michal
T1  - Characterizing the regulation of proton antiport across the thylakoid membrane
N2  - Die Energie, die zum Antrieb photochemischer Reaktionen benötigt 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 häufiger Änderungen der Lichtintensität. Der Thylakoid-Ionentransport kann den Energiefluss durch einen Photosyntheseapparat an die Lichtverfügbarkeit anpassen, indem er die pmf-Zusammensetzung verändert. Die Dissipation von ΔΨ verringert die Ladungsrekombination am Photosystem II, so dass ein Anstieg der ΔpH-Komponente eine Rückkopplung zur Herabregulierung der Photosynthese auslösen kann. Der durch den K+-Austausch-Antiporter 3 (KEA3) gesteuerte K+/H+-Antiport reduziert den ΔpH-Anteil von pmf und dämpft dadurch das nicht-photochemische Quenching (NPQ). Infolgedessen erhöht sich die Photosyntheseeffizienz beim Übergang zu geringerer Lichtintensität. Ziel dieser Arbeit war es, Antworten auf Fragen zur Regulierung der KEA3-Aktivität 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-Aktivität aufweisen, eine zentrale Rolle bei der Regulierung der Photosynthese und des Pflanzenwachstums unter stationären Bedingungen spielt. Das Fehlen von KEA3 in der cgl160-Mutante führt zu einer starken Beeinträchtigung des Wachstums, da die Photosynthese aufgrund des erhöhten pH-abhängigen NPQs und des verringerten Elektronenflusses durch den Cytochrom b6f-Komplex eingeschränkt ist. Die Überexpression von KEA3 in der cgl160-Mutante erhöht die Ladungsrekombination im Photosystem II und fördert die Photosynthese. In Zeiten geringer ATP-Synthase-Aktivität profitieren die Pflanzen also von der KEA3-Aktivität. KEA3 unterliegt einer Dimerisierung über seinen regulatorischen C-Terminus (RCT). Der RCT reagiert auf Veränderungen der Lichtintensität, da die Pflanzen, die KEA3 ohne diese Domäne exprimieren, einen reduzierten Lichtschutzmechanismus bei Lichtintensitätsschwankungen aufweisen. Allerdings fixieren diese Pflanzen während der Photosynthese-Induktionsphase mehr Kohlenstoff als Gegenleistung für 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 Veränderungen in der Stroma-Umgebung abhängt. Die Regulierung der KEA3-Aktivität überschneidet sich mit den pH-Änderungen im Stroma, die bei Lichtschwankungen auftreten. Es hat sich gezeigt, dass ATP und ADP eine Affinität zum heterolog exprimierten KEA3 RCT haben. Eine solche Wechselwirkung verursacht Konformationsänderungen in der RCT-Struktur. Die Faltung der RCT-Liganden-Interaktion hängt vom pH-Wert der Umgebung ab. Mit einer Kombination aus Bioinformatik und In-vitro-Ansatz wurde die ATP-Bindungsstelle am RCT lokalisiert. Das Einfügen einer Punktmutation in der KEA3-RCT Bindungsstelle in planta führte zu einer Deregulierung der Antiporteraktivität beim Übergang zu wenig Licht. Die in dieser Arbeit vorgestellten Daten ermöglichten es uns, die Rolle von KEA3 bei der Anpassung der Photosynthese umfassender zu bewerten und Modelle zur Regulierung der KEA3-Aktivität während des Übergangs zwischen verschiedenen Lichtintensitäten vorzuschlagen.
N2  - The energy required to drive photochemical reactions is derived from charge separation across the thylakoid membrane. As the consequence of difference in proton concentration between chloroplasts stroma and thylakoid lumen, a proton motive force (pmf) is generated. The pmf is composed out of the proton gradient (ΔpH) and membrane potential (ΔΨ), and together they drive the ATP synthesis. In nature, the amount of energy fueling photosynthesis varies due to frequent changes in the light intensity. Thylakoid ion transport can adapt the energy flow through a photosynthetic apparatus to the light availability by adjusting the pmf composition. Dissipation of ΔΨ reduces the charge recombination at the photosystem II, allowing for an increase in ΔpH component to trigger a feedback downregulation of photosynthesis. K+ Exchange Antiporter 3 (KEA3) driven K+/H+ antiport reduces the ΔpH fraction of pmf, thereby dampening a non-photochemical quenching (NPQ). As a result, it increases the photosynthesis efficiency during the transition to lower light intensity. This thesis aimed to find the answers for questions concerning KEA3 activity regulation and its role in plant development. Presented data shows that in plants lacking chloroplast ATP synthase assembly factor CGL160 with decreased ATP synthase activity, KEA3 has a pivotal role in photosynthesis regulation and plant growth during steady-state conditions. Lack of KEA3 in cgl160 mutant results in a strong growth impairment, as photosynthesis is limited due to increased pH-dependent NPQ and decreased electron flow through cytochrome b6f complex. Overexpression of KEA3 in cgl160 mutant increases charge recombination at photosystem II, promoting photosynthesis. Thus, during periods of low ATP synthase activity, plants benefit from KEA3 activity. The KEA3 undergoes dimerization via its regulatory C-terminus (RCT). The RCT responds to changes in light intensity as the plants expressing KEA3 without this domain show reduced photo-protective mechanism in light intensity transients. However, those plants fix more carbon during the photosynthesis induction phase as a trade-off for a long-term photoprotection, showing KEA3 regulatory role in plant development. The KEA3 RCT is facing thylakoid stroma, thus its regulation depends on light-induced changes in the stromal environment. KEA3 activity regulation overlaps with the stromal pH changes occurring during light fluctuations. The ATP and ADP has shown to have an affinity towards heterologously expressed KEA3 RCT. Such interaction causes conformational changes in RCT structure. The fold change of RCT-ligand interaction depends on the environmental pH value. With a combination of bioinformatics and in vitro approach, the ATP binding site at RCT was located. Introduction of binding site point mutation in planta KEA3 RCT resulted in antiporter activity deregulation during transition to low light. Together, the data presented in this thesis allowed us to assess more broadly a KEA3 role in photosynthesis adjustment and propose the models of KEA3 activity regulation throughout transition in light intensity.
KW  - plant
KW  - photosynthesis
KW  - thylakoid
KW  - ion transport
KW  - fluctuating light
KW  - Pflanze
KW  - Photosynthese
KW  - Thylakoid
KW  - Ionentransport
KW  - schwankendes Licht
Y1  - 2021
ER  - 
TY  - JOUR
A1  - Tung, Wing Tai
A1  - Sun, Xianlei
A1  - Wang, Weiwei
A1  - Xu, Xun
A1  - Ma, Nan
A1  - Lendlein, Andreas
T1  - Structure, mechanical properties and degradation behavior of electrospun PEEU fiber meshes and films
JF  - MRS advances : a journal of the Materials Research Society (MRS)
N2  - The capability of a degradable implant to provide mechanical support depends on its degradation behavior. Hydrolytic degradation was studied for a polyesteretherurethane (PEEU70), which consists of poly(p-dioxanone) (PPDO) and poly(epsilon-caprolactone) (PCL) segments with a weight ratio of 70:30 linked by diurethane junction units. PEEU70 samples prepared in the form of meshes with average fiber diameters of 1.5 mu m (mesh1.5) and 1.2 mu m (mesh1.2), and films were sterilized and incubated in PBS at 37 degrees C with 5 vol% CO2 supply for 1 to 6 weeks. Degradation features, such as cracks or wrinkles, became apparent from week 4 for all samples. Mass loss was found to be 11 wt%, 6 wt%, and 4 wt% for mesh1.2, mesh1.5, and films at week 6. The elongation at break decreased to under 20% in two weeks for mesh1.2. In case of the other two samples, this level of degradation was achieved after 4 weeks. The weight average molecular weight of both PEEU70 mesh and film samples decreased to below 30 kg/mol when elongation at break dropped below 20%. The time period of sustained mechanical stability of PEEU70-based meshes depends on the fiber diameter and molecular weight.
Y1  - 2021
U6  - https://doi.org/10.1557/s43580-020-00001-0
SN  - 2059-8521
VL  - 6
IS  - 10
SP  - 276
EP  - 282
PB  - Springer Nature Switzerland AG
CY  - Cham
ER  -