TY - JOUR A1 - Warken, Sophie Friederike A1 - Fohlmeister, Jens Bernd A1 - Schröder-Ritzrauh, Andrea A1 - Constantin, Silviu A1 - Spötl, Christoph A1 - Gerdes, Axel A1 - Esper, Jan A1 - Frank, Norbert A1 - Arps, Jennifer A1 - Terente, Mihai A1 - Riechelmann, Dana Felicitas Christine A1 - Mangini, Augusto A1 - Scholz, Denis T1 - Reconstruction of late Holocene autumn/winter precipitation variability in SW Romania from a high-resolution speleothem trace element record JF - Earth & planetary science letters N2 - We present the first high-resolution trace element (Mg/Ca, Sr/Ca, Ba/Ca) record from a stalagmite in southwestern Romania covering the last 3.6 ka, which provides the potential for quantitative climate reconstruction. Precise age control is based on three independent dating methods, in particular for the last 250 yr, where chemical lamina counting is combined with the identification of the 20th century radiocarbon bomb peak and Th-230/U dating. Long-term cave monitoring and model simulations of drip water and speleothem elemental variability indicate that precipitation-related processes are the main drivers of speleothem Mg/Ca ratios. Calibration against instrumental climate data shows a significant anti-correlation of speleothem Mg/Ca ratios with autumn/winter (October to March) precipitation (r = -0.61, p < 0.01), which is statistically robust when considering age uncertainties and auto-correlation. This relationship is used to develop a quantitative reconstruction of autumn/winter precipitation. During the late Holocene, our data suggest a heterogeneous pattern of past regional winter hydroclimate in the Carpathian/Balkan realm, along with intermittent weakening of the dominant influence of North Atlantic forcing. In agreement with other regional paleo-hydrological reconstructions, the observed variability reveals periodically occurring strong NW-SE hydro-climate gradients. We hypothesize, that this pattern is caused by shifts of the eastern edge of the area of influence of the NAO across central eastern Europe due to the confluence of North Atlantic forcing, and other climatic features such as the East Atlantic/Western Russia (EAWR) pattern. (C) 2018 Elsevier B.V. All rights reserved. KW - speleothem KW - trace elements KW - proxy calibration KW - precipitation reconstruction KW - Romania KW - North Atlantic forcing Y1 - 2018 U6 - https://doi.org/10.1016/j.epsl.2018.07.027 SN - 0012-821X SN - 1385-013X VL - 499 SP - 122 EP - 133 PB - Elsevier CY - Amsterdam ER - TY - GEN A1 - Plath, Martin A1 - Hermann, Bernd A1 - Schröder, Christine A1 - Riesch, Rüdiger A1 - Tobler, Michael A1 - García de León, Francisco J. A1 - Schlupp, Ingo A1 - Tiedemann, Ralph T1 - Locally adapted fish populations maintain small-scale genetic differentiation despite perturbation by a catastrophic flood event N2 - Background: Local adaptation to divergent environmental conditions can promote population genetic differentiation even in the absence of geographic barriers and hence, lead to speciation. Perturbations by catastrophic events, however, can distort such parapatric ecological speciation processes. Here, we asked whether an exceptionally strong flood led to homogenization of gene pools among locally adapted populations of the Atlantic molly (Poecilia mexicana, Poeciliidae) in the Cueva del Azufre system in southern Mexico, where two strong environmental selection factors (darkness within caves and/or presence of toxic H2S in sulfidic springs) drive the diversification of P. mexicana. Nine nuclear microsatellites as well as heritable female life history traits (both as a proxy for quantitative genetics and for trait divergence) were used as markers to compare genetic differentiation, genetic diversity, and especially population mixing (immigration and emigration) before and after the flood. Results: Habitat type (i.e., non-sulfidic surface, sulfidic surface, or sulfidic cave), but not geographic distance was the major predictor of genetic differentiation. Before and after the flood, each habitat type harbored a genetically distinct population. Only a weak signal of individual dislocation among ecologically divergent habitat types was uncovered (with the exception of slightly increased dislocation from the Cueva del Azufre into the sulfidic creek, El Azufre). By contrast, several lines of evidence are indicative of increased flood-induced dislocation within the same habitat type, e.g., between different cave chambers of the Cueva del Azufre. Conclusions: The virtual absence of individual dislocation among ecologically different habitat types indicates strong natural selection against migrants. Thus, our current study exemplifies that ecological speciation in this and other systems, in which extreme environmental factors drive speciation, may be little affected by temporary perturbations, as adaptations to physico-chemical stressors may directly affect the survival probability in divergent habitat types. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 162 Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-48599 ER - TY - JOUR A1 - Kramer-Schadt, Stephanie A1 - Niedballa, Jürgen A1 - Pilgrim, John D. A1 - Schröder-Esselbach, Boris A1 - Lindenborn, Jana A1 - Reinfelder, Vanessa A1 - Stillfried, Milena A1 - Heckmann, Ilja A1 - Scharf, Anne K. A1 - Augeri, Dave M. A1 - Cheyne, Susan M. A1 - Hearn, Andrew J. A1 - Ross, Joanna A1 - Macdonald, David W. A1 - Mathai, John A1 - Eaton, James A1 - Marshall, Andrew J. A1 - Semiadi, Gono A1 - Rustam, Rustam A1 - Bernard, Henry A1 - Alfred, Raymond A1 - Samejima, Hiromitsu A1 - Duckworth, J. W. A1 - Breitenmoser-Wuersten, Christine A1 - Belant, Jerrold L. A1 - Hofer, Heribert A1 - Wilting, Andreas T1 - The importance of correcting for sampling bias in MaxEnt species distribution models JF - Diversity & distributions : a journal of biological invasions and biodiversity N2 - AimAdvancement in ecological methods predicting species distributions is a crucial precondition for deriving sound management actions. Maximum entropy (MaxEnt) models are a popular tool to predict species distributions, as they are considered able to cope well with sparse, irregularly sampled data and minor location errors. Although a fundamental assumption of MaxEnt is that the entire area of interest has been systematically sampled, in practice, MaxEnt models are usually built from occurrence records that are spatially biased towards better-surveyed areas. Two common, yet not compared, strategies to cope with uneven sampling effort are spatial filtering of occurrence data and background manipulation using environmental data with the same spatial bias as occurrence data. We tested these strategies using simulated data and a recently collated dataset on Malay civet Viverra tangalunga in Borneo. LocationBorneo, Southeast Asia. MethodsWe collated 504 occurrence records of Malay civets from Borneo of which 291 records were from 2001 to 2011 and used them in the MaxEnt analysis (baseline scenario) together with 25 environmental input variables. We simulated datasets for two virtual species (similar to a range-restricted highland and a lowland species) using the same number of records for model building. As occurrence records were biased towards north-eastern Borneo, we investigated the efficacy of spatial filtering versus background manipulation to reduce overprediction or underprediction in specific areas. ResultsSpatial filtering minimized omission errors (false negatives) and commission errors (false positives). We recommend that when sample size is insufficient to allow spatial filtering, manipulation of the background dataset is preferable to not correcting for sampling bias, although predictions were comparatively weak and commission errors increased. Main ConclusionsWe conclude that a substantial improvement in the quality of model predictions can be achieved if uneven sampling effort is taken into account, thereby improving the efficacy of species conservation planning. KW - Borneo KW - carnivora KW - conservation planning KW - ecological niche modelling KW - maximum entropy (MaxEnt) KW - sampling bias KW - Southeast Asia KW - species distribution modelling KW - viverridae Y1 - 2013 U6 - https://doi.org/10.1111/ddi.12096 SN - 1366-9516 SN - 1472-4642 VL - 19 IS - 11 SP - 1366 EP - 1379 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Dormann, Carsten F. A1 - Schymanski, Stanislaus J. A1 - Cabral, Juliano Sarmento A1 - Chuine, Isabelle A1 - Graham, Catherine A1 - Hartig, Florian A1 - Kearney, Michael A1 - Morin, Xavier A1 - Römermann, Christine A1 - Schröder-Esselbach, Boris A1 - Singer, Alexander T1 - Correlation and process in species distribution models: bridging a dichotomy JF - Journal of biogeography N2 - Within the field of species distribution modelling an apparent dichotomy exists between process-based and correlative approaches, where the processes are explicit in the former and implicit in the latter. However, these intuitive distinctions can become blurred when comparing species distribution modelling approaches in more detail. In this review article, we contrast the extremes of the correlativeprocess spectrum of species distribution models with respect to core assumptions, model building and selection strategies, validation, uncertainties, common errors and the questions they are most suited to answer. The extremes of such approaches differ clearly in many aspects, such as model building approaches, parameter estimation strategies and transferability. However, they also share strengths and weaknesses. We show that claims of one approach being intrinsically superior to the other are misguided and that they ignore the processcorrelation continuum as well as the domains of questions that each approach is addressing. Nonetheless, the application of process-based approaches to species distribution modelling lags far behind more correlative (process-implicit) methods and more research is required to explore their potential benefits. Critical issues for the employment of species distribution modelling approaches are given, together with a guideline for appropriate usage. We close with challenges for future development of process-explicit species distribution models and how they may complement current approaches to study species distributions. KW - Hypothesis generation KW - mechanistic model KW - parameterization KW - process-based model KW - species distribution model KW - SDM KW - uncertainty KW - validation Y1 - 2012 U6 - https://doi.org/10.1111/j.1365-2699.2011.02659.x SN - 0305-0270 VL - 39 IS - 12 SP - 2119 EP - 2131 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Costard, Sylvia A1 - Stadie, Nicole A1 - Ritter, Christiane A1 - Moll, Kristina A1 - Landerl, Karin A1 - Kohnen, Saskia A1 - Kentner, Gerrit A1 - Bethmann, Anja A1 - Scheich, Henning A1 - Brechmann, André A1 - De Kok, Dörte A1 - Berger, Frauke A1 - Sticher, Heike A1 - Czepluch, Christine A1 - Mätzener, Flurina A1 - Wilmes, Stefanie A1 - Hadert, Sandra A1 - Frank, Ulrike A1 - Mäder, Mark A1 - Westermann, Antje A1 - Meinusch, Miriam A1 - Neumann, Sandra A1 - Düsterhöft, Stefanie A1 - Posse, Dorothea A1 - Puritz, Caroline A1 - Seidl, Rainer Ottis A1 - Etzien, Maria A1 - Machleb, Franziska A1 - Lorenz, Antje A1 - Höger, Maria A1 - Schröder, Astrid A1 - Busch, Tobias A1 - Heide, Judith A1 - Tagoe, Tanja A1 - Watermeyer, Melanie A1 - Höhle, Barbara A1 - Kauschke, Christina ED - Hanne, Sandra ED - Fritzsche, Tom ED - Ott, Susan ED - Adelt, Anne T1 - Spektrum Patholinguistik = Schwerpunktthema: Lesen lernen: Diagnostik und Therapie bei Störungen des Leseerwerbs T1 - Spektrum Patholinguistik = Key issue: Learning to read: Assessment and intervention in developmental reading disorders N2 - Am 20. November 2010 fand an der Universität Potsdam das 4. Herbsttreffen Patholinguistik statt. Die Konferenzreihe wird regelmäßig seit 2007 vom Verband für Patholinguistik e.V. (vpl) durchgeführt. Der vorliegende Tagungsband veröffentlicht die Hauptvorträge des Herbsttreffens zum Thema "Lesen lernen: Diagnostik und Therapie bei Störungen des Leseerwerbs". Des Weiteren sind die Beiträge promovierender bzw. promovierter PatholinguistInnen sowie der Posterpräsentationen enthalten. N2 - On November 20, 2010, the 4th Herbsttreffen Patholinguistik took place at the University of Potsdam. This annual conference is organized by the Verband für Patholinguistik e.V. (vpl). The main topic was "Learning to read: Assessment and intervention in developmental dyslexia". These proceedings contain the four main lectures, the contributed talks of the "Spektrum Patholinguistik" covering various psycho- and neurolinguistic research areas, and the abstracts of the presented posters. T3 - Spektrum Patholinguistik - 4 KW - Patholinguistik KW - Sprachtherapie KW - Leseerwerb KW - Dyslexie KW - Lese-Rechtschreib-Schwäche KW - patholinguistics KW - speech/language therapy KW - reading development KW - reading skills KW - dyslexia Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-53146 SN - 978-3-86956-145-5 SN - 1869-3822 SN - 1866-9433 IS - 4 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - THES A1 - Schröder, Christine T1 - Identifizierung und Charakterisierung der Isoflavon-umsetzenden Enzyme aus dem humanen Darmbakterium Slackia isoflavoniconvertens T1 - Identification and characterization of isoflavone-converting enzymes of the human gut bacterium Slackia isoflavoniconvertens N2 - Aufgrund ihrer potenziell gesundheitsfördernden Wirkung sind die polyphenolischen Isoflavone für die menschliche Ernährung von großem Interesse. Eine Vielzahl an experimentellen und epidemiologischen Studien zeigen für die in Soja enthaltenen Isoflavone Daidzein und Genistein eine präventive Wirkung bezüglich hormon-abhängiger und altersbedingter Erkrankungen, wie Brust- und Prostatakrebs, Osteoporose, Herz-Kreislauf-Erkrankungen sowie des menopausalen Syndroms. Die Metabolisierung und Bioaktivierung dieser sekundären Pflanzenstoffe durch die humane intestinale Darmmikrobiota ist individuell unterschiedlich. Nur in einem geringen Teil der westlichen Bevölkerung wird der Daidzein-Metabolit Equol durch spezifische Darmbakterien gebildet. Ein isoliertes Equol-produzierendes Bakterium des menschlichen Darmtrakts ist Slackia isoflavoniconvertens. Anhand dieser Spezies sollten die bislang unbekannten, an der Umsetzung von Daidzein und Genistein beteiligten Enzyme identifiziert und charakterisiert werden. Fermentationsexperimente mit S. isoflavoniconvertens zeigten, dass die Gene der Daidzein und Genistein-umsetzenden Enzyme nicht konstitutiv exprimiert werden, sondern induziert werden müssen. Mit Hilfe der zweidimensionalen differentiellen Gelelektrophorese wurden sechs Proteine detektiert, welche in einer S. isoflavoniconvertens-Kultur in Anwesenheit von Daidzein induziert wurden. Auf Grundlage einzelner Peptidsequenzen erfolgte die Sequenzierung eines Genkomplexes mit den in gleicher Orientierung angeordneten Genen der durch Daidzein induzierten Proteine. Sequenzvergleiche identifizierten zudem äquivalente Genprodukte zu den Proteinen von S. isoflavoniconvertens in anderen Equolproduzierenden Bakterien. Nach der heterologen Expression in Escherichia coli wurden drei dieser Gene durch enzymatische Aktivitätstests als Daidzein-Reduktase (DZNR), Dihydrodaidzein-Reduktase (DHDR) und Tetrahydrodaidzein-Reduktase (THDR) identifiziert. Die Kombination der E. coli-Zellextrakte führte zur vollständigen Umsetzung von Daidzein über Dihydrodaidzein zu Equol. Neben Daidzein setzte die DZNR auch Genistein zu Dihydrogenistein um. Dies erfolgte mit einer größeren Umsatzgeschwindigkeit im Vergleich zur Reduktion von Daidzein zu Dihydrodaidzein. Enzymatische Aktivitätstests mit dem Zellextrakt von S. isoflavoniconvertens zeigten ebenfalls eine schnellere Umsetzung von Genistein. Die Kombination der rekombinanten DHDR und THDR führte zur Umsetzung von Dihydrodaidzein zu Equol. Der korrespondierende Metabolit 5-Hydroxyequol konnte als Endprodukt des Genistein-Metabolismus nicht detektiert werden. Zur Reinigung der drei identifizierten Reduktasen wurden diese genetisch an ein Strep-tag fusioniert und mittels Affinitätschromatographie gereinigt. Die übrigen durch Daidzein induzierten Proteine IfcA, IfcBC und IfcE wurden ebenfalls in E. coli exprimiert und als Strep-Fusionsproteine gereinigt. Vergleichende Aktivitätstests identifizierten das induzierte Protein IfcA als Dihydrodaidzein-Racemase. Diese katalysierte die Umsetzung des (R)- und (S)-Enantiomers von Dihydrodaidzein und Dihydrogenistein zum korrespondierenden Racemat. Neben dem Elektronentransfer-Flavoprotein IfcBC wurden auch die THDR, DZNR und IfcE als FAD-haltige Flavoproteine identifiziert. Zudem handelte es sich bei IfcE um ein Eisen-Schwefel-Protein. Nach Induktion der für die Daidzein-Umsetzung kodierenden Gene wurden mehrere verschieden lange mRNA-Transkripte gebildet. Dies zeigte, dass die Transkription des durch Daidzein induzierten Genkomplexes in S. isoflavoniconvertens nicht in Form eines einzelnen Operonsystems erfolgte. Auf Grundlage der identifizierten Daidzein-umsetzenden Enzyme kann der Mechanismus der bakteriellen Umsetzung von Isoflavonen durch S. isoflavoniconvertens eingehend erforscht werden. Die ermittelten Gensequenzen der durch Daidzein induzierten Proteine sowie die korrespondierenden Gene weiterer Equol-produzierender Bakterien bieten zudem die Möglichkeit der mikrobiellen Metagenomanalyse im humanen Darmtrakt. N2 - Gut bacteria play a crucial role in the metabolism of dietary isoflavones which have been implicated in the prevention of hormone-dependent and age-related diseases. Only the intestinal bacteria are able to catalyze the bioactivation of the main soybean isoflavones daidzein and genistein to equol and 5-hydroxy-equol, respectively. Although several equolforming gut bacteria have been isolated in recent years, the knowledge on the involved enzymes is still scarce. Slackia isoflavoniconvertens represents one of the few equol-forming gut bacteria isolated from humans. Growth experiments with S. isoflavoniconvertens indicated that the enzymes catalyzing the conversion of daidzein and genistein were inducible by these isoflavones. Using two-dimensional difference gel electrophoresis (2D-DIGE), several proteins were found to be upregulated in S. isoflavoniconvertens cells grown in the presence of daidzein. Based on selected protein sequences, a cluster of eight genes was identified encoding the daidzeininduced proteins. Sequence analysis revealed also similarities of daidzein-induced proteins to corresponding enzymes from other equol-forming human gut bacteria. The heterologous expression of three of those proteins in Escherichia coli and enzyme activity tests identified them as a daidzein reductase (DZNR), a dihydrodaidzein reductase (DHDR) and a tetrahydrodaidzein reductase (THDR). The combined cell extracts catalyzed the complete conversion of daidzein to equol. The recombinant DZNR also converted genistein to the intermediate dihydrogenistein at higher rates than observed for the conversion of daidzein to dihydrodaidzein. Higher rates were also observed with S. isoflavoniconvertens cell extracts. In combination, the recombinant DHDR and THDR catalyzed the reduction of dihydrodaidzein to equol, while the corresponding formation product 5-hydroxy-equol was not observed. The three reductases were functionally expressed as Strep-tag fusion proteins and purified by a one-step affinity chromatography. In addition, the remaining daidzein-induced proteins IfcA, IfcBC and IfcE were successfully expressed in E. coli and purified. In a comparative enzyme activity test, IfcA was identified as a dihydrodaidzein racemase, which converts the (R)- and (S)-enantiomers of dihydrodaidzein and dihydrogenistein to the corresponding racemate. Flavin analysis revealed flavin adenine dinucleotide (FAD) as the cofactor of THDR, DZNR, IfcE and also of the putative heterodimeric electron tansfer flavoprotein IfcBC. In addition, IfcE was identified as iron-sulfur enzyme. The analysis of intergenic regions and gene expression indicated a non-operon genetic structure of daidzein-induced proteins, because mRNA expression occurs at different transcriptional units. Furthermore, the transcription start site was determined for ifcA as the first gene of daidzein-induced gene cluster. In summary, the identification and incipient characterization of the daidzein-induced enzymes provides the basis for detection corresponding genes in other equol-forming gut bacteria within the microbial metagenome of the human gut. The results enable also further studies to elucidate the catalytic mechanism underlying the isoflavone bioactivation by S. isoflavoniconvertens and to clarify the regulation of enzyme induction. KW - Isoflavone KW - Darmbakterium KW - Equol KW - Proteine KW - Reduktase KW - isoflavones KW - gut microbiota KW - equol KW - protein KW - reductase Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-80065 ER - TY - JOUR A1 - Aichert, Ingrid A1 - Staiger, Anja A1 - Schulte-Mäter, Anne A1 - Becker-Redding, Ulrike A1 - Stahn, Corinna A1 - Peschke, Claudia A1 - Heide, Judith A1 - Ott, Susan A1 - Herrmann, Heike A1 - Völsch, Juliane A1 - Mayer, Jörg A1 - Rohnke, Lucie A1 - Frank, Ulrike A1 - Stadie, Nicole A1 - Jentsch, Nadine A1 - Blech, Anke A1 - Kurtenbach, Stephanie A1 - Thieke, Johanna A1 - Schröder, Astrid A1 - Stahn, Corinna A1 - Hörnig, Robin A1 - Burchert, Frank A1 - De Bleser, Ria A1 - Heister, Julian A1 - Bartels, Luise A1 - Würzner, Kay-Michael A1 - Böhme, Romy A1 - Burmester, Juliane A1 - Krajewski, Melanie A1 - Nager, Wido A1 - Jungehülsing, Gerhard Jan A1 - Wartenburger, Isabell A1 - Jöbges, Michael A1 - Schwilling, Eleonore A1 - Lidzba, Karen A1 - Winkler, Susanne A1 - Konietzko, Andreas A1 - Krägeloh-Mann, Ingeborg A1 - Rilling, Eva A1 - Wilken, Rainer A1 - Wismann, Kathrin A1 - Glandorf, Birte A1 - Hoffmann, Hannah A1 - Hinnenkamp, Christiane A1 - Rohlmann, Insa A1 - Ludewigt, Jacqueline A1 - Bittner, Christian A1 - Orlov, Tatjana A1 - Claus, Katrin A1 - Ehemann, Christine A1 - Winnecken, Andreas A1 - Hummel, Katja A1 - Breitenstein, Sarah ED - Wahl, Michael ED - Stahn, Corinna ED - Hanne, Sandra ED - Fritzsche, Tom T1 - Spektrum Patholinguistik = Schwerpunktthema: Von der Programmierung zur Artikulation : Sprechapraxie bei Kindern und Erwachsenen N2 - Das 3. Herbsttreffen Patholinguistik fand am 21. November 2009 an der Universität Potsdam statt. Der vorliegende Tagungsband enthält die drei Hauptvorträge zum Schwerpunktthema „Von der Programmierung zu Artikulation: Sprechapraxie bei Kindern und Erwachsenen“. Darüber hinaus enthält der Band die Beiträge aus dem Spektrum Patholinguistik, sowie die Abstracts der Posterpräsentationen. N2 - The 3rd Herbsttreffen Patholinguistik was held on November 21st, 2009 at the University of Potsdam. These proceedings contain the three main lectures of the central topic „From programming to articulation: Apraxia of speech of children and adults “. Additionally this volume contains the contributions of Spektrum Patholinguistik, as well as the abstracts of the poster presentations. T3 - Spektrum Patholinguistik - 3 KW - Patholinguistik KW - Sprechapraxie KW - Sprachtherapie KW - patholinguistics KW - apraxia of speech KW - speech and language therapy Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-45470 SN - 978-3-86956-079-3 SN - 1869-3822 SN - 1866-9433 IS - 3 PB - Universitätsverlag Potsdam CY - Potsdam ER -