@article{SolgerKunzFinketal.2019, author = {Solger, Franziska and Kunz, Tobias C. and Fink, Julian and Paprotka, Kerstin and Pfister, Pauline and Hagen, Franziska and Schumacher, Fabian and Kleuser, Burkhard and Seibel, J{\"u}rgen and Rudel, Thomas}, title = {A role of sphingosine in the intracellular survival of Neisseria gonorrhoeae}, series = {Frontiers in Cellular and Infection Microbiology}, volume = {10}, journal = {Frontiers in Cellular and Infection Microbiology}, publisher = {Frontiers Media}, address = {Lausanne}, issn = {2235-2988}, doi = {10.3389/fcimb.2020.00215}, pages = {12}, year = {2019}, abstract = {Obligate human pathogenic Neisseria gonorrhoeae are the second most frequent bacterial cause of sexually transmitted diseases. These bacteria invade different mucosal tissues and occasionally disseminate into the bloodstream. Invasion into epithelial cells requires the activation of host cell receptors by the formation of ceramide-rich platforms. Here, we investigated the role of sphingosine in the invasion and intracellular survival of gonococci. Sphingosine exhibited an anti-gonococcal activity in vitro. We used specific sphingosine analogs and click chemistry to visualize sphingosine in infected cells. Sphingosine localized to the membrane of intracellular gonococci. Inhibitor studies and the application of a sphingosine derivative indicated that increased sphingosine levels reduced the intracellular survival of gonococci. We demonstrate here, that sphingosine can target intracellular bacteria and may therefore exert a direct bactericidal effect inside cells.}, language = {en} } @techreport{CaliendoRodriguezGuio2023, type = {Working Paper}, author = {Caliendo, Marco and Rodr{\´i}guez Guio, Daniel Felipe}, title = {Divergent thinking and post-launch entrepreneurial outcomes}, series = {CEPA Discussion Papers}, journal = {CEPA Discussion Papers}, number = {68}, issn = {2628-653X}, doi = {10.25932/publishup-60740}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-607408}, pages = {58}, year = {2023}, abstract = {Divergent thinking is the ability to produce numerous and diverse responses to questions or tasks, and it is used as a predictor of creative achievement. It plays a significant role in the business organization's innovation process and the recognition of new business opportunities. Drawing upon the cumulative process model of creativity in entrepreneurship, we hypothesize that divergent thinking has a lasting effect on post-launch entrepreneurial outcomes related to innovation and growth, but that this relation might not always be linear. Additionally, we hypothesize that domain-specific experience has a moderating role in this relation. We test our hypotheses based on a representative longitudinal sample of 457 German business founders, which we observe up until 40 months after start-up. We find strong relative effects for innovation and growth outcomes. For survival we find conclusive evidence for non-linearities in the effects of divergent thinking. Additionally, we show that such effects are moderated by the type of domain-specific experience that entrepreneurs gathered pre-launch, as it shapes the individual's ideational abilities to fit into more sophisticated strategies regarding entrepreneurial creative achievement. Our findings have relevant policy implications in characterizing and identifying business start-ups with growth and innovation potential, allowing a more efficient allocation of public and private funds.}, language = {en} } @article{CaliendoGoethnerWeissenberger2019, author = {Caliendo, Marco and Goethner, Maximilian and Weißenberger, Martin}, title = {Entrepreneurial persistence beyond survival: Measurement and determinants}, series = {Journal of Small Business Management}, volume = {58}, journal = {Journal of Small Business Management}, number = {3}, publisher = {Taylor \& Francis}, address = {London}, pages = {32}, year = {2019}, abstract = {Entrepreneurial persistence is demonstrated by an entrepreneur's continued positive maintenance of entrepreneurial motivation and constantly renewed active engagement in a new business venture despite counterforces or enticing alternatives. It thus is a crucial factor for entrepreneurs when pursuing and exploiting their business opportunities and in realizing potential economic gains and benefits. Using rich data on a representative sample of German business founders, we investigated the determinants of entrepreneurial persistence. Next to observed survival, we also constructed a hybrid persistence measure capturing the motivational dimension of persistence. We analyzed the influence of individual-level (human capital and personality) and business-related characteristics on both measures as well as their relative importance. We found that the two indicators emphasize different aspects of persistence. For the survival indicator, the predictive power was concentrated in business characteristics and human capital, while for hybrid persistence the dominant factors were business characteristics and personality. Finally, we showed that results were heterogeneous across subgroups. In particular, formerly unemployed founders did not differ in survival chances, but they were more likely to lack a high psychological commitment to their business ventures.}, language = {en} } @misc{CaliendoGoethnerWeissenberger2019, author = {Caliendo, Marco and Goethner, Maximilian and Weißenberger, Martin}, title = {Entrepreneurial persistence beyond survival: Measurement and determinants}, series = {Postprints der Universit{\"a}t Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe}, number = {3}, issn = {1867-5808}, doi = {10.25932/publishup-52481}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-524813}, pages = {34}, year = {2019}, abstract = {Entrepreneurial persistence is demonstrated by an entrepreneur's continued positive maintenance of entrepreneurial motivation and constantly renewed active engagement in a new business venture despite counterforces or enticing alternatives. It thus is a crucial factor for entrepreneurs when pursuing and exploiting their business opportunities and in realizing potential economic gains and benefits. Using rich data on a representative sample of German business founders, we investigated the determinants of entrepreneurial persistence. Next to observed survival, we also constructed a hybrid persistence measure capturing the motivational dimension of persistence. We analyzed the influence of individual-level (human capital and personality) and business-related characteristics on both measures as well as their relative importance. We found that the two indicators emphasize different aspects of persistence. For the survival indicator, the predictive power was concentrated in business characteristics and human capital, while for hybrid persistence the dominant factors were business characteristics and personality. Finally, we showed that results were heterogeneous across subgroups. In particular, formerly unemployed founders did not differ in survival chances, but they were more likely to lack a high psychological commitment to their business ventures.}, language = {en} } @article{SchaelickeSobischMartinCreuzburgetal.2019, author = {Sch{\"a}licke, Svenja and Sobisch, Lydia-Yasmin and Martin-Creuzburg, Dominik and Wacker, Alexander}, title = {Food quantity-quality co-limitation}, series = {Freshwater biology}, volume = {64}, journal = {Freshwater biology}, number = {5}, publisher = {Wiley}, address = {Hoboken}, issn = {0046-5070}, doi = {10.1111/fwb.13272}, pages = {903 -- 912}, year = {2019}, abstract = {Food quantity and quality are highly variable in natural systems. Therefore, their interplay and the associated effects on consumer population growth are important for predator-prey interactions and community dynamics. Experiments in which consumers were exposed to elemental nutrient limitations along food quantity gradients suggest that food quality effects on consumer performance are relevant only at high food quantities. However, elemental nutrients act differently on physiological processes than biochemical nutrients. So far, the interactive effects of food quantity and biochemical compounds on consumer performance have been insufficiently studied. We studied interactive effects of food quantity and biochemical food quality on population growth, including fecundity and survival, of the freshwater rotifer Brachionus calyciflorus. We hypothesised that these life history traits are differently affected by the availability of biochemical nutrients and that food quality effects gain importance with increasing food quantity. In a first experiment, we established food quantity and quality gradients by providing rotifers with different concentrations of a low-quality food, the sterol-free cyanobacterium Synechococcus elongatus, supplemented with increasing amounts of cholesterol. In a second experiment, food quantity and quality gradients were established by providing different proportions of two prey species differing in biochemical food quality, i.e. S.elongatus and the lipid-rich alga Nannochloropsis limnetica, at different total food concentrations. We found that the effects of cholesterol supplementation on population growth increased with increasing food quantity. This interactive effect on population growth was mainly due to food quality effects on fecundity, as effects on survival remained constant along the food quantity gradient. In contrast, when feeding on the mixed algal diet, the food quality effect associated with increasing the proportion of the high-quality alga did not change along the food quantity gradient. The data on survival and fecundity demonstrate the missing interactive effect of food quantity and quality on population growth, as both traits were oppositely affected. Survival was affected by food quality primarily at low food quantity, whereas food quality effects on fecundity were stronger at high food quantity. Our results highlight the significance of essential biochemicals in mediating the interactive effects of food quantity and quality on population growth. The interplay between food quantity and biochemical food quality limitation seems to influence resource allocation patterns in order to optimise survival or reproduction, which may strongly affect population dynamics in variable environments. As opposed to exploring the function of a single nutrient via supplementation, using algae mixtures allowed us to assess food quality effects on consumer performance in a more natural context by taking potential interactive effects of multiple co-limiting nutrients into account.}, language = {en} } @article{JbeilySuckertGonnertetal.2013, author = {Jbeily, Nayla and Suckert, Iris and Gonnert, Falk A. and Acht, Benedikt and Bockmeyer, Clemens L. and Grossmann, Sascha D. and Blaess, Markus F. and L{\"u}th, Anja and Deigner, Hans-Peter and Bauer, Michael and Claus, Ralf A.}, title = {Hyperresponsiveness of mice deficient in plasma-secreted sphingomyelinase reveals its pivotal role in early phase of host response}, series = {Journal of lipid research}, volume = {54}, journal = {Journal of lipid research}, number = {2}, publisher = {American Society for Biochemistry and Molecular Biology}, address = {Bethesda}, issn = {0022-2275}, doi = {10.1194/jlr.M031625}, pages = {410 -- 424}, year = {2013}, abstract = {Plasma secretion of acid sphingomyelinase is a hallmark of cellular stress response resulting in the formation of membrane embedded ceramide-enriched lipid rafts and the reorganization of receptor complexes. Consistently, decompartmentalization of ceramide formation from inert sphingomyelin has been associated with signaling events and regulation of the cellular phenotype. Herein, we addressed the question of whether the secretion of acid sphingomyelinase is involved in host response during sepsis. We found an exaggerated clinical course in mice genetically deficient in acid sphingomyelinase characterized by an increased bacterial burden, an increased phagocytotic activity, and a more pronounced cytokine storm. Moreover, on a functional level, leukocyte-endothelial interaction was found diminished in sphingomyelinase-deficient animals corresponding to a distinct leukocytes' phenotype with respect to rolling and sticking as well as expression of cellular surface proteins.(jlr) We conclude that hydrolysis of membrane-embedded sphingomyelin, triggered by circulating sphingomyelinase, plays a pivotal role in the first line of defense against invading microorganisms. This function might be essential during the early phase of infection leading to an adaptive response of remote cells and tissues.-Jbeily, N., I. Suckert, F. A. Gonnert, B. Acht, C. L. Bockmeyer, S. D. Grossmann, M. F. Blaess, A. Lueth, H.-P. Deigner, M. Bauer, and R. A. Claus. Hyperresponsiveness of mice deficient in plasma-secreted sphingomyelinase reveals its pivotal role in early phase of host response. J. Lipid Res. 2013. 54: 410-424.}, language = {en} } @misc{PinhasiFernandesSiraketal.2015, author = {Pinhasi, Ron and Fernandes, Daniel and Sirak, Kendra and Novak, Mario and Connell, Sarah and Alpaslan-Roodenberg, Song{\"u}l and Gerritsen, Fokke and Moiseyev, Vyacheslav and Gromov, Andrey and Raczky, P{\´a}l and Anders, Alexandra and Pietrusewsky, Michael and Rollefson, Gary and Jovanovic, Marija and Trinhhoang, Hiep and Bar-Oz, Guy and Oxenham, Marc and Matsumura, Hirofumi and Hofreiter, Michael}, title = {Optimal ancient DNA yields from the inner ear part of the human petrous bone}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschafliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschafliche Reihe}, number = {515}, issn = {1866-8372}, doi = {10.25932/publishup-40955}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-409557}, pages = {13}, year = {2015}, abstract = {The invention and development of next or second generation sequencing methods has resulted in a dramatic transformation of ancient DNA research and allowed shotgun sequencing of entire genomes from fossil specimens. However, although there are exceptions, most fossil specimens contain only low (similar to 1\% or less) percentages of endogenous DNA. The only skeletal element for which a systematically higher endogenous DNA content compared to other skeletal elements has been shown is the petrous part of the temporal bone. In this study we investigate whether (a) different parts of the petrous bone of archaeological human specimens give different percentages of endogenous DNA yields, (b) there are significant differences in average DNA read lengths, damage patterns and total DNA concentration, and (c) it is possible to obtain endogenous ancient DNA from petrous bones from hot environments. We carried out intra-petrous comparisons for ten petrous bones from specimens from Holocene archaeological contexts across Eurasia dated between 10,0001,800 calibrated years before present (cal. BP). We obtained shotgun DNA sequences from three distinct areas within the petrous: a spongy part of trabecular bone (part A), the dense part of cortical bone encircling the osseous inner ear, or otic capsule (part B), and the dense part within the otic capsule (part C). Our results confirm that dense bone parts of the petrous bone can provide high endogenous aDNA yields and indicate that endogenous DNA fractions for part C can exceed those obtained for part B by up to 65-fold and those from part A by up to 177-fold, while total endogenous DNA concentrations are up to 126-fold and 109-fold higher for these comparisons. Our results also show that while endogenous yields from part C were lower than 1\% for samples from hot (both arid and humid) parts, the DNA damage patterns indicate that at least some of the reads originate from ancient DNA molecules, potentially enabling ancient DNA analyses of samples from hot regions that are otherwise not amenable to ancient DNA analyses.}, language = {en} } @misc{ReilRosenfeldImholtetal.2017, author = {Reil, Daniela and Rosenfeld, Ulrike and Imholt, Christian and Schmidt, Sabrina and Ulrich, Rainer G. and Eccard, Jana and Jacob, Jens}, title = {Puumala hantavirus infections in bank vole populations}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {957}, issn = {1866-8372}, doi = {10.25932/publishup-43123}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431232}, pages = {15}, year = {2017}, abstract = {Background In Europe, bank voles (Myodes glareolus) are widely distributed and can transmit Puumala virus (PUUV) to humans, which causes a mild to moderate form of haemorrhagic fever with renal syndrome, called nephropathia epidemica. Uncovering the link between host and virus dynamics can help to prevent human PUUV infections in the future. Bank voles were live trapped three times a year in 2010-2013 in three woodland plots in each of four regions in Germany. Bank vole population density was estimated and blood samples collected to detect PUUV specific antibodies. Results We demonstrated that fluctuation of PUUV seroprevalence is dependent not only on multi-annual but also on seasonal dynamics of rodent host abundance. Moreover, PUUV infection might affect host fitness, because seropositive individuals survived better from spring to summer than uninfected bank voles. Individual space use was independent of PUUV infections. Conclusions Our study provides robust estimations of relevant patterns and processes of the dynamics of PUUV and its rodent host in Central Europe, which are highly important for the future development of predictive models for human hantavirus infection risk.}, language = {en} } @techreport{CaliendoKritikosRodriguezetal.2023, type = {Working Paper}, author = {Caliendo, Marco and Kritikos, Alexander and Rodriguez, Daniel and Stier, Claudia}, title = {Self-Efficacy and Entrepreneurial Performance of Start-Ups}, series = {CEPA Discussion Papers}, journal = {CEPA Discussion Papers}, number = {61}, issn = {2628-653X}, doi = {10.25932/publishup-57252}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-572527}, pages = {41}, year = {2023}, abstract = {Self-efficacy reflects the self-belief that one can persistently perform difficult and novel tasks while coping with adversity. As such beliefs reflect how individuals behave, think, and act, they are key for successful entrepreneurial activities. While existing literature mainly analyzes the influence of the task-related construct of entrepreneurial self-efficacy, we take a different perspective and investigate, based on a representative sample of 1,405 German business founders, how the personality characteristic of generalized self-efficacy influences start-up performance as measured by a broad set of business outcomes up to 19 months after business creation. Outcomes include start-up survival and entrepreneurial income, as well as growth-oriented outcomes such as job creation and innovation. We find statistically significant and economically important positive effects of high scores of self-efficacy on start-up survival and entrepreneurial income, which become even stronger when focusing on the growth-oriented outcome of innovation. Furthermore, we observe that generalized self-efficacy is similarly distributed between female and male business founders, with effects being partly stronger for female entrepreneurs. Our findings are important for policy instruments that are meant to support firm growth by facilitating the design of more target-oriented offers for training, coaching, and entrepreneurial incubators.}, language = {en} } @article{CaliendoKritikosRodriguezetal.2023, author = {Caliendo, Marco and Kritikos, Alexander and Rodr{\´i}guez, Daniel and Stier, Claudia}, title = {Self-efficacy and entrepreneurial performance of start-ups}, series = {Small business economics}, journal = {Small business economics}, publisher = {Springer Science}, address = {Dordrecht}, issn = {0921-898X}, doi = {10.1007/s11187-022-00728-0}, pages = {25}, year = {2023}, abstract = {Self-efficacy reflects the self-belief that one can persistently perform difficult and novel tasks while coping with adversity. As such beliefs reflect how individuals behave, think, and act, they are key for successful entrepreneurial activities. While existing literature mainly analyzes the influence of the task-related construct of entrepreneurial self-efficacy, we take a different perspective and investigate, based on a representative sample of 1,405 German business founders, how the personality characteristic of generalized self-efficacy influences start-up performance as measured by a broad set of business outcomes up to 19 months after business creation. Outcomes include start-up survival and entrepreneurial income, as well as growth-oriented outcomes such as job creation and innovation. We find statistically significant and economically important positive effects of high scores of self-efficacy on start-up survival and entrepreneurial income, which become even stronger when focusing on the growth-oriented outcome of innovation. Furthermore, we observe that generalized self-efficacy is similarly distributed between female and male business founders, with effects being partly stronger for female entrepreneurs. Our findings are important for policy instruments that are meant to support firm growth by facilitating the design of more target-oriented offers for training, coaching, and entrepreneurial incubators.}, language = {en} }