@article{BrietzkeDietzKellingetal.2017, author = {Brietzke, Thomas Martin and Dietz, Thomas and Kelling, Alexandra and Schilde, Uwe and Bois, Juliana and Kelm, Harald and Reh, Manuel and Schmitz, Markus and Koerzdoerfer, Thomas and Leimk{\"u}hler, Silke and Wollenberger, Ulla and Krueger, Hans-Joerg and Holdt, Hans-J{\"u}rgen}, title = {The 1,6,7,12-Tetraazaperylene Bridging Ligand as an Electron Reservoir and Its Disulfonato Derivative as Redox Mediator in an Enzyme-Electrode Process}, series = {Chemistry - a European journal}, volume = {23}, journal = {Chemistry - a European journal}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0947-6539}, doi = {10.1002/chem.201703639}, pages = {15583 -- 15587}, year = {2017}, abstract = {The homodinuclear ruthenium(II) complex [{Ru(l-N4Me2)}(2)(-tape)](PF6)(4) {[1](PF6)(4)} (l-N4Me2=N,N-dimethyl-2,11-diaza[3.3](2,6)-pyridinophane, tape=1,6,7,12-tetraazaperylene) can store one or two electrons in the energetically low-lying * orbital of the bridging ligand tape. The corresponding singly and doubly reduced complexes [{Ru(l-N4Me2)}(2)(-tape(.-))](PF6)(3) {[2](PF6)(3)} and [{Ru(l-N4Me2)}(2)(-tape(2-))](PF6)(2) {[3](PF6)(2)}, respectively, were electrochemically generated, successfully isolated and fully characterized by single-crystal X-ray crystallography, spectroscopic methods and magnetic susceptibility measurements. The singly reduced complex [2](PF6)(3) contains the -radical tape(.-) and the doubly reduced [3](PF6)(2) the diamagnetic dianion tape(2-) as bridging ligand, respectively. Nucleophilic aromatic substitution at the bridging tape in [1](4+) by two sulfite units gave the complex [{Ru(l-N4Me2)}(2){-tape-(SO3)(2)}](2+) ([4](2+)). Complex dication [4](2+) was exploited as a redox mediator between an anaerobic homogenous reaction solution of an enzyme system (sulfite/sulfite oxidase) and the electrode via participation of the low-energy *-orbital of the disulfonato-substituted bridging ligand tape-(SO3)(2)(2-) (E-red1=-0.1V versus Ag/AgCl/1m KCl in water).}, language = {en} } @article{KaufmannDuffusMitrovaetal.2018, author = {Kaufmann, Hans Paul and Duffus, Benjamin R. and Mitrova, Biljana and Iobbi-Nivol, Chantal and Teutloff, Christian and Nimtz, Manfred and Jaensch, Lothar and Wollenberger, Ulla and Leimk{\"u}hler, Silke}, title = {Modulating the Molybdenum Coordination Sphere of Escherichia coli Trimethylamie N-Oxide Reductase}, series = {Biochemistry}, volume = {57}, journal = {Biochemistry}, number = {7}, publisher = {American Chemical Society}, address = {Washington}, issn = {0006-2960}, doi = {10.1021/acs.biochem.7b01108}, pages = {1130 -- 1143}, year = {2018}, abstract = {The well-studied enterobacterium Escherichia coli present in the human gut can reduce trimethylamine N-oxide (TMAO) to trimethylamine during anaerobic respiration. The TMAO reductase TorA is a monomeric, bis-molybdopterin guanine dinucleotide (bis-MGD) cofactor-containing enzyme that belongs to the dimethyl sulfoxide reductase family of molybdoenzymes. We report on a system for the in vitro reconstitution of TorA with molybdenum cofactors (Moco) from different sources. Higher TMAO reductase activities for TorA were obtained when using Moco sources containing a sulfido ligand at the molybdenum atom. For the first time, we were able to isolate functional bis-MGD from Rhodobacter capsulatus formate dehydrogenase (FDH), which remained intact in its isolated state and after insertion into apo-TorA yielded a highly active enzyme. Combined characterizations of the reconstituted TorA enzymes by electron paramagnetic resonance spectroscopy and direct electrochemistry emphasize that TorA activity can be modified by changes in the Mo coordination sphere. The combination of these results together with studies of amino acid exchanges at the active site led us to propose a novel model for binding of the substrate to the molybdenum atom of TorA.}, language = {en} } @book{MetteDuschlHlavaceketal.2008, author = {Mette, Dieter and Duschl, Reinhold and Hlavacek, Hans and Klose, Veronika and Ostermeier, Lydia and Schranner, Matthias and Schrauth, Silke}, title = {AWT aktuell : Arbeit, Wirtschaft, Technik ; Ausgabe B f{\"u}r Haupt-/Mittelschulen in Bayern, Lehrermaterialien Bd. 8}, publisher = {Oldenbourg}, address = {M{\"u}nchen}, isbn = {978-3-637-88218-8}, pages = {128 S.}, year = {2008}, language = {de} } @book{MetteDuschlHlavaceketal.2008, author = {Mette, Dieter and Duschl, Reinhold and Hlavacek, Hans and Klose, Veronika and Ostermeier, Lydia and Schranner, Matthias and Schrauth, Silke}, title = {AWT aktuell : Arbeit, Wirtschaft, Technik, ; Ausgabe B f{\"u}r Haupt-/Mittelschulen in Bayern, Lehrermaterialien Bd. 9}, publisher = {Oldenbourg}, address = {M{\"u}nchen}, isbn = {978-3-637-88219-5}, pages = {144 S.}, year = {2008}, language = {de} } @book{GabbertWeikard1998, author = {Gabbert, Silke and Weikard, Hans-Peter}, title = {Food deficits, food security and food aid : concepts and measurement}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-8589}, publisher = {Universit{\"a}t Potsdam}, year = {1998}, abstract = {The concepts of food deficit, hunger, undernourishment and food security are discussed. Axioms and indices for the assessment of nutrition of individuals and groups are suggested. Furthermore a measure for food aid donor performance is developed and applied to a sample of bilateral and multilateral donors providing food aid for African countries.}, language = {en} } @book{Hans2004, author = {Hans, Silke}, title = {Migrants in Germany, Sweden and the United Kingdom}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-11248}, publisher = {Universit{\"a}t Potsdam}, year = {2004}, abstract = {Contents: 1. Introduction 2. Migration and Assimilation - Theoretical Approaches 2.1 Meaning and Definition of the Terms Migration and Migrant 2.2 Milton M. Gordon - Sub Processes of Assimilation 2.3 Hartmut Esser - Acculturation, Integration, and Assimilation 2.4 The Concept of Integration and Assimilation 2.5 Straight-line Assimilation and its Implications 2.6 Segmented Assimilation and its Implications 3. Social Inequality and Welfare - Theoretical Approaches 3.1 Dimensions of Inequality 3.2 Welfare Regimes and Social Inequality 3.3 Migration, Assimilation and Inequality 4. Research Design 4.1 Research Question and General Proceeding 4.2 Sample and Data Base 4.3 Operationalisation and Indicators 5. Migration, Welfare and Inequality in Three European Countries 6. Empirical Results 6.1 Performance of Migrants Compared With Natives 6.2 Different Trajectories of Assimilation 6.3 Trajectories of Segmented Assimilation and their Determinants 6.4 Policies, Attitudes and Assimilation - An Aggregate Analysis 6.5 Summary - What Determines the Performance of Migrants? 7. Discussion of Empirical Results in Terms of Theoretical Approaches 7.1 The Situation of Migrants in Three European Countries 7.2 Assessment of the Trajectories of Assimilation 8. Conclusion - Future Prospects of Migration in Europe}, language = {en} } @article{MareljaChowdhuryDoscheetal.2013, author = {Marelja, Zvonimir and Chowdhury, Mita Mullick and Dosche, Carsten and Hille, Carsten and Baumann, Otto and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Leimk{\"u}hler, Silke}, title = {The L-cysteine desulfurase NFS1 is localized in the cytosol where it provides the sulfur for molybdenum cofactor biosynthesis in humans}, series = {PLoS one}, volume = {8}, journal = {PLoS one}, number = {4}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0060869}, pages = {13}, year = {2013}, abstract = {In humans, the L-cysteine desulfurase NFS1 plays a crucial role in the mitochondrial iron-sulfur cluster biosynthesis and in the thiomodification of mitochondrial and cytosolic tRNAs. We have previously demonstrated that purified NFS1 is able to transfer sulfur to the C-terminal domain of MOCS3, a cytosolic protein involved in molybdenum cofactor biosynthesis and tRNA thiolation. However, no direct evidence existed so far for the interaction of NFS1 and MOCS3 in the cytosol of human cells. Here, we present direct data to show the interaction of NFS1 and MOCS3 in the cytosol of human cells using Forster resonance energy transfer and a split-EGFP system. The colocalization of NFS1 and MOCS3 in the cytosol was confirmed by immunodetection of fractionated cells and localization studies using confocal fluorescence microscopy. Purified NFS1 was used to reconstitute the lacking molybdoenzyme activity of the Neurospora crassa nit-1 mutant, giving additional evidence that NFS1 is the sulfur donor for Moco biosynthesis in eukaryotes in general.}, language = {en} } @unpublished{KaufmannMazzoccoDowkeretal.2013, author = {Kaufmann, Liane and Mazzocco, Michele M. and Dowker, Ann and von Aster, Michael G. and Goebel, Silke M. and Grabner, Roland H. and Henik, Avishai and Jordan, Nancy C. and Karmiloff-Smith, Annette D. and Kucian, Karin and Rubinsten, Orly and Szucs, Denes and Shalev, Ruth and Nuerk, Hans-Christoph}, title = {Dyscalculia from a developmental and differential perspective}, series = {Frontiers in psychology}, volume = {4}, journal = {Frontiers in psychology}, number = {2}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-1078}, doi = {10.3389/fpsyg.2013.00516}, pages = {5}, year = {2013}, language = {en} } @book{MetteDuschlHlavaceketal.2008, author = {Mette, Dieter and Duschl, Reinhold and Hlavacek, hans and Klose, Veronika and Ostermeier, Lydia and Schranner, matthias and Schrauth, Silke}, title = {AWT aktuell : Arbeit, Wirtschaft, Technik ; Ausgabe B f{\"u}r Haupt-/Mittelschulen in Bayern, Bd. 9}, publisher = {Oldenbourg}, address = {M{\"u}nchen; D{\"u}sseldorf; Stuttgart}, isbn = {978-3-637-88209-6}, pages = {128 S.}, year = {2008}, language = {de} } @book{MetteDuschlHlavaceketal.2008, author = {Mette, Dieter and Duschl, Reinhold and Hlavacek, Hans and Klose, Veronika and Ostermeier, Lydia and Schranner, Matthias and Schrauth, Silke}, title = {AWT aktuell : Arbeit, Wirtschaft, Technik ; Ausgabe B f{\"u}r Haupt-/Mittelschulen in Bayern, Bd. 8}, publisher = {Oldenbourg}, address = {M{\"u}nchen; D{\"u}sseldorf; Stuttgart}, isbn = {978-3-637-88208-9}, pages = {112 S.}, year = {2008}, language = {de} } @book{MetteDuschlHlavaceketal.2008, author = {Mette, Dieter and Duschl, Reinhold and Hlavacek, Hans and Klose, Veronika and Ostermeier, Lydia and Schranner, Matthias and Schrauth, Silke}, title = {AWT aktuell : Arbeit, Wirtschaft, Technik ; Ausgabe B f{\"u}r Haupt-/Mittelschulen in Bayern, Bd. 7}, publisher = {Oldenbourg}, address = {M{\"u}nchen; D{\"u}sseldorf; Stuttgart}, isbn = {978-3-637-88207-2}, pages = {96 S.}, year = {2008}, language = {de} } @article{WeikardGabbert1998, author = {Weikard, Hans-Peter and Gabbert, Silke}, title = {Orientiert sich die Vergabe von Nahrungsmittelhilfe am Bedarf?}, year = {1998}, language = {de} } @article{ChowdhuryDoscheLoehmannsroebenetal.2012, author = {Chowdhury, Mita Mullick and Dosche, Carsten and Loehmannsr{\"o}ben, Hans-Gerd and Leimk{\"u}hler, Silke}, title = {Dual role of the molybdenum cofactor biosynthesis protein MOCS3 in tRNA thiolation and molybdenum cofactor biosynthesis in humans}, series = {The journal of biological chemistry}, volume = {287}, journal = {The journal of biological chemistry}, number = {21}, publisher = {American Society for Biochemistry and Molecular Biology}, address = {Bethesda}, issn = {0021-9258}, doi = {10.1074/jbc.M112.351429}, pages = {17297 -- 17307}, year = {2012}, abstract = {We studied two pathways that involve the transfer of persulfide sulfur in humans, molybdenum cofactor biosynthesis and tRNA thiolation. Investigations using human cells showed that the two-domain protein MOCS3 is shared between both pathways. MOCS3 has an N-terminal adenylation domain and a C-terminal rhodanese-like domain. We showed that MOCS3 activates both MOCS2A and URM1 by adenylation and a subsequent sulfur transfer step for the formation of the thiocarboxylate group at the C terminus of each protein. MOCS2A and URM1 are beta-grasp fold proteins that contain a highly conserved C-terminal double glycine motif. The role of the terminal glycine of MOCS2A and URM1 was examined for the interaction and the cellular localization with MOCS3. Deletion of the C-terminal glycine of either MOCS2A or URM1 resulted in a loss of interaction with MOCS3. Enhanced cyan fluorescent protein and enhanced yellow fluorescent protein fusions of the proteins were constructed, and the fluorescence resonance energy transfer efficiency was determined by the decrease in the donor lifetime. The cellular localization results showed that extension of the C terminus with an additional glycine of MOCS2A and URM1 altered the localization of MOCS3 from the cytosol to the nucleus.}, language = {en} } @misc{ArnisonBibbBierbaumetal.2013, author = {Arnison, Paul G. and Bibb, Mervyn J. and Bierbaum, Gabriele and Bowers, Albert A. and Bugni, Tim S. and Bulaj, Grzegorz and Camarero, Julio A. and Campopiano, Dominic J. and Challis, Gregory L. and Clardy, Jon and Cotter, Paul D. and Craik, David J. and Dawson, Michael and Dittmann-Th{\"u}nemann, Elke and Donadio, Stefano and Dorrestein, Pieter C. and Entian, Karl-Dieter and Fischbach, Michael A. and Garavelli, John S. and Goeransson, Ulf and Gruber, Christian W. and Haft, Daniel H. and Hemscheidt, Thomas K. and Hertweck, Christian and Hill, Colin and Horswill, Alexander R. and Jaspars, Marcel and Kelly, Wendy L. and Klinman, Judith P. and Kuipers, Oscar P. and Link, A. James and Liu, Wen and Marahiel, Mohamed A. and Mitchell, Douglas A. and Moll, Gert N. and Moore, Bradley S. and Mueller, Rolf and Nair, Satish K. and Nes, Ingolf F. and Norris, Gillian E. and Olivera, Baldomero M. and Onaka, Hiroyasu and Patchett, Mark L. and Piel, J{\"o}rn and Reaney, Martin J. T. and Rebuffat, Sylvie and Ross, R. Paul and Sahl, Hans-Georg and Schmidt, Eric W. and Selsted, Michael E. and Severinov, Konstantin and Shen, Ben and Sivonen, Kaarina and Smith, Leif and Stein, Torsten and Suessmuth, Roderich D. and Tagg, John R. and Tang, Gong-Li and Truman, Andrew W. and Vederas, John C. and Walsh, Christopher T. and Walton, Jonathan D. and Wenzel, Silke C. and Willey, Joanne M. and van der Donk, Wilfred A.}, title = {Ribosomally synthesized and post-translationally modified peptide natural products overview and recommendations for a universal nomenclature}, series = {Natural product reports : a journal of current developments in bio-organic chemistry}, volume = {30}, journal = {Natural product reports : a journal of current developments in bio-organic chemistry}, number = {1}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {0265-0568}, doi = {10.1039/c2np20085f}, pages = {108 -- 160}, year = {2013}, abstract = {This review presents recommended nomenclature for the biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs), a rapidly growing class of natural products. The current knowledge regarding the biosynthesis of the >20 distinct compound classes is also reviewed, and commonalities are discussed.}, language = {en} } @book{BeierHechtJaegeretal.2000, author = {Beier, Hans-Dieter and Hecht, Rico and J{\"a}ger, Nico and Kozub, Peter and Lange, Eva and Markt, Silke and Tietze, Peter and Vormelker, Caroline and Wenzel, Gabriele and Zorn, Olivia and Fatah, Abdel Fatah Ahmed Abdel and Selman, Ibrahim Mohamed and Rabou, Nagi Moissa Abd and Ghadiri, Risq and Badawi, Mochsen Helmi and Fatah, Ezad Mohamed Abdel and Maksoud, Mohamed Abd El and Gaballa, Gaballa Ali}, title = {Tell Basta : Vorl{\"a}ufiger Bericht {\"u}ber die XII. Grabungskampange in Tell Basta (Ostdelta)}, publisher = {Univ.}, address = {Potsdam}, pages = {128 S., 2 Kt., 1 Brille}, year = {2000}, language = {de} } @misc{GrossartVandenWyngaertKagamietal.2019, author = {Grossart, Hans-Peter and Van den Wyngaert, Silke and Kagami, Maiko and Wurzbacher, Christian and Cunliffe, Michael and Rojas-Jimenz, Keilor}, title = {Fungi in aquatic ecosystems}, series = {Nature reviews. Microbiology}, volume = {17}, journal = {Nature reviews. Microbiology}, number = {6}, publisher = {Nature Publ. Group}, address = {Basingstoke}, issn = {1740-1526}, doi = {10.1038/s41579-019-0175-8}, pages = {339 -- 354}, year = {2019}, abstract = {Fungi are phylogenetically and functionally diverse ubiquitous components of almost all ecosystems on Earth, including aquatic environments stretching from high montane lakes down to the deep ocean. Aquatic ecosystems, however, remain frequently overlooked as fungal habitats, although fungi potentially hold important roles for organic matter cycling and food web dynamics. Recent methodological improvements have facilitated a greater appreciation of the importance of fungi in many aquatic systems, yet a conceptual framework is still missing. In this Review, we conceptualize the spatiotemporal dimensions, diversity, functions and organismic interactions of fungi in structuring aquatic food webs. We focus on currently unexplored fungal diversity, highlighting poorly understood ecosystems, including emerging artificial aquatic habitats.}, language = {en} } @article{VandenWyngaertSetoRojasJimenezetal.2017, author = {Van den Wyngaert, Silke and Seto, Kensuke and Rojas-Jimenez, Keilor and Kagami, Maiko and Grossart, Hans-Peter}, title = {A New Parasitic Chytrid, Staurastromyces oculus (Rhizophydiales, Staurastromy-cetaceae fam. nov.), Infecting the Freshwater Desmid Staurastrum sp.}, series = {Protist}, volume = {168}, journal = {Protist}, publisher = {Elsevier}, address = {Jena}, issn = {1434-4610}, doi = {10.1016/j.protis.2017.05.001}, pages = {392 -- 407}, year = {2017}, abstract = {Chytrids are a diverse group of ubiquitous true zoosporic fungi. The recent molecular discovery of a large diversity of undescribed chytrids has raised awareness on their important, but so far understudied ecological role in aquatic ecosystems. In the pelagic zone, of both freshwater and marine ecosystems, many chytrid species have been morphologically described as parasites on almost all major groups of phytoplankton. However, the majority of these parasitic chytrids has rarely been isolated and lack DNA sequence data, resulting in a large proportion of "dark taxa" in databases. Here, we report on the isolation and in-depth morphological, molecular and host range characterization of a chytrid infecting the common freshwater desmid Staurastrum sp. We provide first insights on the metabolic activity of the different chytrid development stages by using the vital dye FUN (R)-1 (2-chloro-4-[2,3-dihydro-3-methyl-[benzo-1,3-thiazol-2-yl]-methylidene]-1-phenylquinolinium iodide). Cross infection experiments suggest that this chytrid is an obligate parasite and specific for the genus Staurastrum sp. Phylogenetic analysis, based on ITS1-5.8S-ITS2 and 28S rDNA sequences, placed it in the order Rhizophydiales. Based on the unique zoospore ultrastructure, combined with thallus morphology, and molecular phylogenetic placement, we describe this parasitic chytrid as a new genus and species Staurastromyces oculus, within a new family Staurastromycetaceae. (C) 2017 Elsevier GmbH. All rights reserved.}, language = {en} } @article{SpillingSchulzPauletal.2016, author = {Spilling, Kristian and Schulz, Kai G. and Paul, Allanah J. and Boxhammer, Tim and Achterberg, Eric Pieter and Hornick, Thomas and Lischka, Silke and Stuhr, Annegret and Bermudez, Rafael and Czerny, Jan and Crawfurd, Kate and Brussaard, Corina P. D. and Grossart, Hans-Peter and Riebesell, Ulf}, title = {Effects of ocean acidification on pelagic carbon fluxes in a mesocosm experiment}, series = {Biogeosciences}, volume = {13}, journal = {Biogeosciences}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1726-4170}, doi = {10.5194/bg-13-6081-2016}, pages = {6081 -- 6093}, year = {2016}, abstract = {About a quarter of anthropogenic CO2 emissions are currently taken up by the oceans, decreasing seawater pH. We performed a mesocosm experiment in the Baltic Sea in order to investigate the consequences of increasing CO2 levels on pelagic carbon fluxes. A gradient of different CO2 scenarios, ranging from ambient (similar to 370 mu atm) to high (similar to 1200 mu atm), were set up in mesocosm bags (similar to 55m(3)). We determined standing stocks and temporal changes of total particulate carbon (TPC), dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and particulate organic carbon (POC) of specific plankton groups. We also measured carbon flux via CO2 exchange with the atmosphere and sedimentation (export), and biological rate measurements of primary production, bacterial production, and total respiration. The experiment lasted for 44 days and was divided into three different phases (I: t0-t16; II: t17-t30; III: t31-t43). Pools of TPC, DOC, and DIC were approximately 420, 7200, and 25 200 mmol Cm-2 at the start of the experiment, and the initial CO2 additions increased the DIC pool by similar to 7\% in the highest CO2 treatment. Overall, there was a decrease in TPC and increase of DOC over the course of the experiment. The decrease in TPC was lower, and increase in DOC higher, in treatments with added CO2. During phase I the estimated gross primary production (GPP) was similar to 100 mmol C m(-2) day(-1), from which 75-95\% was respired, similar to 1\% ended up in the TPC (including export), and 5-25\% was added to the DOC pool. During phase II, the respiration loss increased to similar to 100\% of GPP at the ambient CO2 concentration, whereas respiration was lower (85-95\% of GPP) in the highest CO2 treatment. Bacterial production was similar to 30\% lower, on average, at the highest CO2 concentration than in the controls during phases II and III. This resulted in a higher accumulation of DOC and lower reduction in the TPC pool in the elevated CO2 treatments at the end of phase II extending throughout phase III. The "extra" organic carbon at high CO2 remained fixed in an increasing biomass of small-sized plankton and in the DOC pool, and did not transfer into large, sinking aggregates. Our results revealed a clear effect of increasing CO2 on the carbon budget and mineralization, in particular under nutrient limited conditions. Lower carbon loss processes (respiration and bacterial remineralization) at elevated CO2 levels resulted in higher TPC and DOC pools than ambient CO2 concentration. These results highlight the importance of addressing not only net changes in carbon standing stocks but also carbon fluxes and budgets to better disentangle the effects of ocean acidification.}, language = {en} } @article{GilingStaehrGrossartetal.2017, author = {Giling, Darren P. and Staehr, Peter A. and Grossart, Hans-Peter and Andersen, Mikkel Rene and Boehrer, Bertram and Escot, Carmelo and Evrendilek, Fatih and Gomez-Gener, Lluis and Honti, Mark and Jones, Ian D. and Karakaya, Nusret and Laas, Alo and Moreno-Ostos, Enrique and Rinke, Karsten and Scharfenberger, Ulrike and Schmidt, Silke R. and Weber, Michael and Woolway, R. Iestyn and Zwart, Jacob A. and Obrador, Biel}, title = {Delving deeper: Metabolic processes in the metalimnion of stratified lakes}, series = {Limnology and oceanography}, volume = {62}, journal = {Limnology and oceanography}, publisher = {Wiley}, address = {Hoboken}, issn = {0024-3590}, doi = {10.1002/lno.10504}, pages = {1288 -- 1306}, year = {2017}, abstract = {Many lakes exhibit seasonal stratification, during which they develop strong thermal and chemical gradients. An expansion of depth-integrated monitoring programs has provided insight into the importance of organic carbon processing that occurs below the upper mixed layer. However, the chemical and physical drivers of metabolism and metabolic coupling remain unresolved, especially in the metalimnion. In this depth zone, sharp gradients in key resources such as light and temperature co-occur with dynamic physical conditions that influence metabolic processes directly and simultaneously hamper the accurate tracing of biological activity. We evaluated the drivers of metalimnetic metabolism and its associated uncertainty across 10 stratified lakes in Europe and North America. We hypothesized that the metalimnion would contribute highly to whole-lake functioning in clear oligotrophic lakes, and that metabolic rates would be highly variable in unstable polymictic lakes. Depth-integrated rates of gross primary production (GPP) and ecosystem respiration (ER) were modelled from diel dissolved oxygen curves using a Bayesian approach. Metabolic estimates were more uncertain below the epilimnion, but uncertainty was not consistently related to lake morphology or mixing regime. Metalimnetic rates exhibited high day-to-day variability in all trophic states, with the metalimnetic contribution to daily whole-lake GPP and ER ranging from 0\% to 87\% and < 1\% to 92\%, respectively. Nonetheless, the metalimnion of low-nutrient lakes contributed strongly to whole-lake metabolism on average, driven by a collinear combination of highlight, low surface-water phosphorous concentration and high metalimnetic volume. Consequently, a single-sensor approach does not necessarily reflect whole-ecosystem carbon dynamics in stratified lakes.}, language = {en} } @article{VandenWyngaertRojasJimenezSetoetal.2018, author = {Van den Wyngaert, Silke and Rojas-Jimenez, Keilor and Seto, Kensuke and Kagami, Maiko and Grossart, Hans-Peter}, title = {Diversity and Hidden Host Specificity of Chytrids Infecting Colonial Volvocacean Algae}, series = {Journal of Eukaryotic Microbiology}, volume = {65}, journal = {Journal of Eukaryotic Microbiology}, number = {6}, publisher = {Wiley}, address = {Hoboken}, issn = {1066-5234}, doi = {10.1111/jeu.12632}, pages = {870 -- 881}, year = {2018}, abstract = {Chytrids are zoosporic fungi that play an important, but yet understudied, ecological role in aquatic ecosystems. Many chytrid species have been morphologically described as parasites on phytoplankton. However, the majority of them have rarely been isolated and lack DNA sequence data. In this study we isolated and cultivated three parasitic chytrids, infecting a common volvocacean host species, Yamagishiella unicocca. To identify the chytrids, we characterized morphology and life cycle, and analyzed phylogenetic relationships based on 18S and 28S rDNA genes. Host range and specificity of the chytrids was determined by cross-infection assays with host strains, characterized by rbcL and ITS markers. We were able to confirm the identity of two chytrid strains as Endocoenobium eudorinae Ingold and Dangeardia mamillata Schroder and described the third chytrid strain as Algomyces stechlinensis gen. et sp. nov. The three chytrids were assigned to novel and phylogenetically distant clades within the phylum Chytridiomycota, each exhibiting different host specificities. By integrating morphological and molecular data of both the parasitic chytrids and their respective host species, we unveiled cryptic host-parasite associations. This study highlights that a high prevalence of (pseudo)cryptic diversity requires molecular characterization of both phytoplankton host and parasitic chytrid to accurately identify and compare host range and specificity, and to study phytoplankton-chytrid interactions in general.}, language = {en} } @misc{FrenkenAlacidBergeretal.2017, author = {Frenken, Thijs and Alacid, Elisabet and Berger, Stella A. and Bourne, Elizabeth Charlotte and Gerphagnon, Melanie and Großart, Hans-Peter and Gsell, Alena S. and Ibelings, Bas W. and Kagami, Maiko and Kupper, Frithjof C. and Letcher, Peter M. and Loyau, Adeline and Miki, Takeshi and Nejstgaard, Jens C. and Rasconi, Serena and Rene, Albert and Rohrlack, Thomas and Rojas-Jimenez, Keilor and Schmeller, Dirk S. and Scholz, Bettina and Seto, Kensuke and Sime-Ngando, Telesphore and Sukenik, Assaf and Van de Waal, Dedmer B. and Van den Wyngaert, Silke and Van Donk, Ellen and Wolinska, Justyna and Wurzbacher, Christian and Agha, Ramsy}, title = {Integrating chytrid fungal parasites into plankton ecology: research gaps and needs}, series = {Environmental microbiology}, volume = {19}, journal = {Environmental microbiology}, publisher = {Wiley}, address = {Hoboken}, issn = {1462-2912}, doi = {10.1111/1462-2920.13827}, pages = {3802 -- 3822}, year = {2017}, abstract = {Chytridiomycota, often referred to as chytrids, can be virulent parasites with the potential to inflict mass mortalities on hosts, causing e.g. changes in phytoplankton size distributions and succession, and the delay or suppression of bloom events. Molecular environmental surveys have revealed an unexpectedly large diversity of chytrids across a wide range of aquatic ecosystems worldwide. As a result, scientific interest towards fungal parasites of phytoplankton has been gaining momentum in the past few years. Yet, we still know little about the ecology of chytrids, their life cycles, phylogeny, host specificity and range. Information on the contribution of chytrids to trophic interactions, as well as co-evolutionary feedbacks of fungal parasitism on host populations is also limited. This paper synthesizes ideas stressing the multifaceted biological relevance of phytoplankton chytridiomycosis, resulting from discussions among an international team of chytrid researchers. It presents our view on the most pressing research needs for promoting the integration of chytrid fungi into aquatic ecology.}, language = {en} } @misc{SpillingSchulzPauletal.2016, author = {Spilling, Kristian and Schulz, Kai Georg and Paul, Allanah J. and Boxhammer, Tim and Achterberg, Eric Pieter and Hornick, Thomas and Lischka, Silke and Stuhr, Annegret and Berm{\´u}dez, Rafael and Czerny, Jan and Crawfurd, Kate and Brussaard, Corina P. D. and Grossart, Hans-Peter and Riebesell, Ulf}, title = {Effects of ocean acidification on pelagic carbon fluxes in a mesocosm experiment}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {544}, issn = {1866-8372}, doi = {10.25932/publishup-41183}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-411835}, pages = {13}, year = {2016}, abstract = {About a quarter of anthropogenic CO2 emissions are currently taken up by the oceans, decreasing seawater pH. We performed a mesocosm experiment in the Baltic Sea in order to investigate the consequences of increasing CO2 levels on pelagic carbon fluxes. A gradient of different CO2 scenarios, ranging from ambient (similar to 370 mu atm) to high (similar to 1200 mu atm), were set up in mesocosm bags (similar to 55m(3)). We determined standing stocks and temporal changes of total particulate carbon (TPC), dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and particulate organic carbon (POC) of specific plankton groups. We also measured carbon flux via CO2 exchange with the atmosphere and sedimentation (export), and biological rate measurements of primary production, bacterial production, and total respiration. The experiment lasted for 44 days and was divided into three different phases (I: t0-t16; II: t17-t30; III: t31-t43). Pools of TPC, DOC, and DIC were approximately 420, 7200, and 25 200 mmol Cm-2 at the start of the experiment, and the initial CO2 additions increased the DIC pool by similar to 7\% in the highest CO2 treatment. Overall, there was a decrease in TPC and increase of DOC over the course of the experiment. The decrease in TPC was lower, and increase in DOC higher, in treatments with added CO2. During phase I the estimated gross primary production (GPP) was similar to 100 mmol C m(-2) day(-1), from which 75-95\% was respired, similar to 1\% ended up in the TPC (including export), and 5-25\% was added to the DOC pool. During phase II, the respiration loss increased to similar to 100\% of GPP at the ambient CO2 concentration, whereas respiration was lower (85-95\% of GPP) in the highest CO2 treatment. Bacterial production was similar to 30\% lower, on average, at the highest CO2 concentration than in the controls during phases II and III. This resulted in a higher accumulation of DOC and lower reduction in the TPC pool in the elevated CO2 treatments at the end of phase II extending throughout phase III. The "extra" organic carbon at high CO2 remained fixed in an increasing biomass of small-sized plankton and in the DOC pool, and did not transfer into large, sinking aggregates. Our results revealed a clear effect of increasing CO2 on the carbon budget and mineralization, in particular under nutrient limited conditions. Lower carbon loss processes (respiration and bacterial remineralization) at elevated CO2 levels resulted in higher TPC and DOC pools than ambient CO2 concentration. These results highlight the importance of addressing not only net changes in carbon standing stocks but also carbon fluxes and budgets to better disentangle the effects of ocean acidification.}, language = {en} } @misc{ZimmermannHornConradGoerlichetal.2019, author = {Zimmermann, Matthias and Horn-Conrad, Antje and G{\"o}rlich, Petra and Krafzik, Carolin and Kampe, Heike and Schlegel, Karoline and Eckardt, Barbara and B{\"u}rkner, Hans-Joachim and Engel, Silke}, title = {Portal Wissen = K{\"u}nstliche Intelligenz}, number = {01/2019}, organization = {Universit{\"a}t Potsdam, Referat f{\"u}r Presse- und {\"O}ffentlichkeitsarbeit}, issn = {2194-4237}, doi = {10.25932/publishup-44094}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-440942}, pages = {97}, year = {2019}, abstract = {Lange gab es auf der Erde Dinge, die konnte nur der Mensch. Doch diese Zeit k{\"o}nnte zu Ende gehen. Mithilfe des universalen Werkzeugs, das uns einzigartig macht - unserer Intelligenz -, haben wir daf{\"u}r gesorgt, dass wir es nicht l{\"a}nger sind. Zumindest wenn es darum geht, kognitive Aufgaben zu l{\"o}sen. K{\"u}nstliche Intelligenz kann inzwischen Schach spielen, Sprache verstehen, Auto fahren. Vieles sogar besser als wir. Wie kam es dazu? Der Philosoph Aristoteles schuf mit seinen Syllogismen die ersten „Gesetze des Denkens", die Mathematiker Blaise Pascal und Wilhelm Leibniz bauten einige der fr{\"u}hesten Rechenmaschinen, der Mathematiker George Boole f{\"u}hrte als erster eine formale Sprache zur Darstellung der Logik ein, der Naturwissenschaftler Alan Turing schuf mit seiner Dechiffriermaschine „Colossus" den ersten programmierbaren Computer. Philosophen, Mathematiker, Psychologen, Linguisten - seit Jahrhunderten entwickeln Wissenschaftlerin- nen und Wissenschaftler Formeln, Maschinen und Theorien, die es m{\"o}glich machen sollen, unsere wertvollste F{\"a}higkeit zu reproduzieren und wom{\"o}glich sogar zu verbessern. Aber was ist das eigentlich: „K{\"u}nstliche Intelligenz"? Schon die Bezeichnung fordert zum Vergleich auf. Ist K{\"u}nstliche Intelligenz wie menschliche Intelligenz? Alan Turing formulierte 1950 einen Test, der eine befriedigende operationale Definition von Intelligenz liefern sollte: Intelligent ist eine Maschine demnach, wenn sie ein dem Menschen gleichwertiges Denkverm{\"o}gen besitzt. Sie muss also bei beliebigen kognitiven Aufgaben dasselbe Niveau erreichen. Beweisen muss sie dies, indem sie einen menschlichen Fragenden glauben l{\"a}sst, sie sei ein Mensch. Keine leichte Sache: Immerhin muss sie daf{\"u}r nat{\"u}rliche Sprache verarbeiten, Wissen speichern, aus diesem Schl{\"u}sse ziehen und Neues lernen k{\"o}nnen. Tats{\"a}chlich entstanden in den vergangenen zehn Jahren etliche KI-Systeme, die in Chat- Gespr{\"a}chen, mit automatisch erzeugten Texten oder Bildern den Test auf die eine oder andere Weise bestanden. Im Fokus stehen nun meist andere Fragen: Braucht KI ihre Sch{\"o}pfer {\"u}berhaupt noch? Wird sie den Menschen nicht nur {\"u}berfl{\"u}geln, sondern eines Tages sogar ersetzen - sei es in der Welt der Arbeit oder sogar dar{\"u}ber hinaus? L{\"o}st KI im Zeitalter der allumfassenden digitalen Vernetzung unsere Probleme - oder wird sie Teil davon? {\"U}ber K{\"u}nstliche Intelligenz, ihr Wesen, ihre Beschr{\"a}nkungen, ihr Potenzial und ihr Verh{\"a}ltnis zum Menschen wird nicht erst diskutiert seitdem es sie gibt. Vor allem Literatur und Kino haben Szenarien mit verschiedenstem Ausgang kreiert. Aber wie sehen das Wissenschaftler, die mit oder zu K{\"u}nstlicher Intelligenz forschen? F{\"u}r die aktuelle Ausgabe des Forschungsmagazins kamen ein Kognitionswissenschaftler, eine Bildungsforscherin und ein Informatiker dar{\"u}ber ins Gespr{\"a}ch. Daneben haben wir uns in der Hochschule nach Projekten umgesehen, deren fachliche Heimat die zahlreichen M{\"o}glichkeiten offenbart, die KI f{\"u}r viele Disziplinen erahnen l{\"a}sst. So geht die Reise in die Geowissenschaften und die Informatik ebenso wie die Wirtschafts-, Gesundheits- und Literaturwissenschaften. Daneben haben wir die Breite der Forschung an der Universit{\"a}t nicht aus den Augen verloren: Ein Jurist f{\"u}hrt ein in die gar nicht so weltferne Sph{\"a}re des Weltraumrechts, w{\"a}hrend Astrophysiker daran arbeiten, dass modernste Teleskope zum richtigen Zeitpunkt genau in die Regionen des Weltraums schauen, wo gerade etwas „los ist". Eine Chemikerin erkl{\"a}rt, warum die Batterie der Zukunft aus dem Drucker kommt, und Molekularbiologen berichten, wie sie stressresistente Pflanzen z{\"u}chten wollen. Mit menschlichem Stress in der Arbeitswelt besch{\"a}ftigt sich nicht nur ein Forschungs-, sondern auch ein Gr{\"u}nderprojekt. Dar{\"u}ber ist in diesem Heft genauso zu lesen wie {\"u}ber aktuelle Studien zum Restless Legs Syndrom bei Kindern oder aber der Situation von Muslimen in Brandenburg. Nicht zuletzt machen wir Sie mit jenen Schafen bekannt, die derzeit im Park Sanssouci weiden - im Auftrag der Wissenschaft. Gar nicht so dumm! Viel Vergn{\"u}gen! Die Redaktion}, language = {de} } @misc{IlicicWoodhouseKarstenetal.2023, author = {Ilicic, Doris and Woodhouse, Jason Nicholas and Karsten, Ulf and Zimmermann, Jonas and Wichard, Thomas and Quartino, Maria Liliana and Campana, Gabriela Laura and Livenets, Alexandra and Van den Wyngaert, Silke and Grossart, Hans-Peter}, title = {Antarctic Glacial Meltwater Impacts the Diversity of Fungal Parasites Associated With Benthic Diatoms in Shallow Coastal Zones}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1290}, issn = {1866-8372}, doi = {10.25932/publishup-57289}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-572895}, pages = {14}, year = {2023}, abstract = {Aquatic ecosystems are frequently overlooked as fungal habitats, although there is increasing evidence that their diversity and ecological importance are greater than previously considered. Aquatic fungi are critical and abundant components of nutrient cycling and food web dynamics, e.g., exerting top-down control on phytoplankton communities and forming symbioses with many marine microorganisms. However, their relevance for microphytobenthic communities is almost unexplored. In the light of global warming, polar regions face extreme changes in abiotic factors with a severe impact on biodiversity and ecosystem functioning. Therefore, this study aimed to describe, for the first time, fungal diversity in Antarctic benthic habitats along the salinity gradient and to determine the co-occurrence of fungal parasites with their algal hosts, which were dominated by benthic diatoms. Our results reveal that Ascomycota and Chytridiomycota are the most abundant fungal taxa in these habitats. We show that also in Antarctic waters, salinity has a major impact on shaping not just fungal but rather the whole eukaryotic community composition, with a diversity of aquatic fungi increasing as salinity decreases. Moreover, we determined correlations between putative fungal parasites and potential benthic diatom hosts, highlighting the need for further systematic analysis of fungal diversity along with studies on taxonomy and ecological roles of Chytridiomycota.}, language = {en} } @article{IlicicWoodhouseKarstenetal.2022, author = {Ilicic, Doris and Woodhouse, Jason Nicholas and Karsten, Ulf and Zimmermann, Jonas and Wichard, Thomas and Quartino, Maria Liliana and Campana, Gabriela Laura and Livenets, Alexandra and Van den Wyngaert, Silke and Grossart, Hans-Peter}, title = {Antarctic Glacial Meltwater Impacts the Diversity of Fungal Parasites Associated With Benthic Diatoms in Shallow Coastal Zones}, series = {Frontiers in microbiology}, journal = {Frontiers in microbiology}, number = {13}, publisher = {Frontiers Media}, address = {Lausanne}, issn = {1664-302X}, doi = {10.3389/fmicb.2022.805694}, pages = {12}, year = {2022}, abstract = {Aquatic ecosystems are frequently overlooked as fungal habitats, although there is increasing evidence that their diversity and ecological importance are greater than previously considered. Aquatic fungi are critical and abundant components of nutrient cycling and food web dynamics, e.g., exerting top-down control on phytoplankton communities and forming symbioses with many marine microorganisms. However, their relevance for microphytobenthic communities is almost unexplored. In the light of global warming, polar regions face extreme changes in abiotic factors with a severe impact on biodiversity and ecosystem functioning. Therefore, this study aimed to describe, for the first time, fungal diversity in Antarctic benthic habitats along the salinity gradient and to determine the co-occurrence of fungal parasites with their algal hosts, which were dominated by benthic diatoms. Our results reveal that Ascomycota and Chytridiomycota are the most abundant fungal taxa in these habitats. We show that also in Antarctic waters, salinity has a major impact on shaping not just fungal but rather the whole eukaryotic community composition, with a diversity of aquatic fungi increasing as salinity decreases. Moreover, we determined correlations between putative fungal parasites and potential benthic diatom hosts, highlighting the need for further systematic analysis of fungal diversity along with studies on taxonomy and ecological roles of Chytridiomycota.}, language = {en} } @article{VandenWyngaertGanzertSetoetal.2022, author = {Van den Wyngaert, Silke and Ganzert, Lars and Seto, Kensuke and Rojas-Jimenez, Keilor and Agha, Ramsy and Berger, Stella A. and Woodhouse, Jason and Padisak, Judit and Wurzbacher, Christian and Kagami, Maiko and Grossart, Hans-Peter}, title = {Seasonality of parasitic and saprotrophic zoosporic fungi: linking sequence data to ecological traits}, series = {ISME journal}, volume = {16}, journal = {ISME journal}, number = {9}, publisher = {Springer Nature}, address = {London}, issn = {1751-7362}, doi = {10.1038/s41396-022-01267-y}, pages = {2242 -- 2254}, year = {2022}, abstract = {Zoosporic fungi of the phylum Chytridiomycota (chytrids) regularly dominate pelagic fungal communities in freshwater and marine environments. Their lifestyles range from obligate parasites to saprophytes. Yet, linking the scarce available sequence data to specific ecological traits or their host ranges constitutes currently a major challenge. We combined 28 S rRNA gene amplicon sequencing with targeted isolation and sequencing approaches, along with cross-infection assays and analysis of chytrid infection prevalence to obtain new insights into chytrid diversity, ecology, and seasonal dynamics in a temperate lake. Parasitic phytoplankton-chytrid and saprotrophic pollen-chytrid interactions made up the majority of zoosporic fungal reads. We explicitly demonstrate the recurrent dominance of parasitic chytrids during frequent diatom blooms and saprotrophic chytrids during pollen rains. Distinct temporal dynamics of diatom-specific parasitic clades suggest mechanisms of coexistence based on niche differentiation and competitive strategies. The molecular and ecological information on chytrids generated in this study will aid further exploration of their spatial and temporal distribution patterns worldwide. To fully exploit the power of environmental sequencing for studies on chytrid ecology and evolution, we emphasize the need to intensify current isolation efforts of chytrids and integrate taxonomic and autecological data into long-term studies and experiments.}, language = {en} }