@article{WeyrichBenzKarletal.2016, author = {Weyrich, Alexandra and Benz, Stephanie and Karl, Stephan and Jeschek, Marie and Jewgenow, Katarina and Fickel, J{\"o}rns}, title = {Paternal heat exposure causes DNA methylation and gene expression changes of Stat3 in Wild guinea pig sons}, series = {Ecology and evolution}, volume = {6}, journal = {Ecology and evolution}, publisher = {Wiley}, address = {Hoboken}, issn = {2045-7758}, doi = {10.1002/ece3.1993}, pages = {2657 -- 2666}, year = {2016}, abstract = {Epigenetic mechanisms convey environmental information through generations and can regulate gene expression. Epigenetic studies in wild mammals are rare, but enable understanding adaptation processes as they may occur in nature. In most wild mammal species, males are the dispersing sex and thus often have to cope with differing habitats and thermal changes more rapidly than the often philopatric females. As temperature is a major environmental selection factor, we investigated whether genetically heterogeneous Wild guinea pig (Cavia aperea) males adapt epigenetically to an increase in temperature, whether that response will be transmitted to the next generation(s), and whether it regulates mRNA expression. Five (F0) adult male guinea pigs were exposed to an increased ambient temperature for 2 months, corresponding to the duration of the species' spermatogenesis. To study the effect of heat, we focused on the main thermoregulatory organ, the liver. We analyzed CpG-methylation changes of male offspring (F1) sired before and after the fathers' heat treatment (as has recently been described in Weyrich et al. [Mol. Ecol., 2015]). Transcription analysis was performed for the three genes with the highest number of differentially methylated changes detected: the thermoregulation gene Signal Transducer and Activator of Transcription 3 (Stat3), the proteolytic peptidase gene Cathepsin Z (Ctsz), and Sirtuin 6 (Sirt6) with function in epigenetic regulation. Stat3 gene expression was significantly reduced (P < 0.05), which indicated a close link between CpG-methylation and expression levels for this gene. The two other genes did not show gene expression changes. Our results indicate the presence of a paternal transgenerational epigenetic effect. Quick adaptation to climatic changes may become increasingly relevant for the survival of wildlife species as global temperatures are rising.}, language = {en} } @article{WeyrichLenzJescheketal.2016, author = {Weyrich, Alexandra and Lenz, Dorina and Jeschek, Marie and Tzu Hung Chung, and Ruebensam, Kathrin and Goeritz, Frank and Jewgenow, Katarina and Fickel, J{\"o}rns}, title = {Paternal intergenerational epigenetic response to heat exposure in male Wild guinea pigs}, series = {Molecular ecology}, volume = {25}, journal = {Molecular ecology}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0962-1083}, doi = {10.1111/mec.13494}, pages = {1729 -- 1740}, year = {2016}, abstract = {Epigenetic modifications, of which DNA methylation is the best studied one, can convey environmental information through generations via parental germ lines. Past studies have focused on the maternal transmission of epigenetic information to the offspring of isogenic mice and rats in response to external changes, whereas heterogeneous wild mammals as well as paternal epigenetic effects have been widely neglected. In most wild mammal species, males are the dispersing sex and have to cope with differing habitats and thermal changes. As temperature is a major environmental factor we investigated if genetically heterogeneous Wild guinea pig (Cavia aperea) males can adapt epigenetically to an increase in temperature and if that response will be transmitted to the next generation(s). Five adult male guinea pigs (F0) were exposed to an increased ambient temperature for 2 months, i.e. the duration of spermatogenesis. We studied the liver (as the main thermoregulatory organ) of F0 fathers and F1 sons, and testes of F1 sons for paternal transmission of epigenetic modifications across generation(s). Reduced representation bisulphite sequencing revealed shared differentially methylated regions in annotated areas between F0 livers before and after heat treatment, and their sons' livers and testes, which indicated a general response with ecological relevance. Thus, paternal exposure to a temporally limited increased ambient temperature led to an 'immediate' and 'heritable' epigenetic response that may even be transmitted to the F2 generation. In the context of globally rising temperatures epigenetic mechanisms may become increasingly relevant for the survival of species.}, language = {en} } @phdthesis{Breuer2016, author = {Breuer, David}, title = {The plant cytoskeleton as a transportation network}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-93583}, school = {Universit{\"a}t Potsdam}, pages = {164}, year = {2016}, abstract = {The cytoskeleton is an essential component of living cells. It is composed of different types of protein filaments that form complex, dynamically rearranging, and interconnected networks. The cytoskeleton serves a multitude of cellular functions which further depend on the cell context. In animal cells, the cytoskeleton prominently shapes the cell's mechanical properties and movement. In plant cells, in contrast, the presence of a rigid cell wall as well as their larger sizes highlight the role of the cytoskeleton in long-distance intracellular transport. As it provides the basis for cell growth and biomass production, cytoskeletal transport in plant cells is of direct environmental and economical relevance. However, while knowledge about the molecular details of the cytoskeletal transport is growing rapidly, the organizational principles that shape these processes on a whole-cell level remain elusive. This thesis is devoted to the following question: How does the complex architecture of the plant cytoskeleton relate to its transport functionality? The answer requires a systems level perspective of plant cytoskeletal structure and transport. To this end, I combined state-of-the-art confocal microscopy, quantitative digital image analysis, and mathematically powerful, intuitively accessible graph-theoretical approaches. This thesis summarizes five of my publications that shed light on the plant cytoskeleton as a transportation network: (1) I developed network-based frameworks for accurate, automated quantification of cytoskeletal structures, applicable in, e.g., genetic or chemical screens; (2) I showed that the actin cytoskeleton displays properties of efficient transport networks, hinting at its biological design principles; (3) Using multi-objective optimization, I demonstrated that different plant cell types sustain cytoskeletal networks with cell-type specific and near-optimal organization; (4) By investigating actual transport of organelles through the cell, I showed that properties of the actin cytoskeleton are predictive of organelle flow and provided quantitative evidence for a coordination of transport at a cellular level; (5) I devised a robust, optimization-based method to identify individual cytoskeletal filaments from a given network representation, allowing the investigation of single filament properties in the network context. The developed methods were made publicly available as open-source software tools. Altogether, my findings and proposed frameworks provide quantitative, system-level insights into intracellular transport in living cells. Despite my focus on the plant cytoskeleton, the established combination of experimental and theoretical approaches is readily applicable to different organisms. Despite the necessity of detailed molecular studies, only a complementary, systemic perspective, as presented here, enables both understanding of cytoskeletal function in its evolutionary context as well as its future technological control and utilization.}, language = {en} } @phdthesis{Nietzsche2016, author = {Nietzsche, Madlen}, title = {Identifizierung und Charakterisierung neuer Komponenten der SnRK1-Signaltransduktion in Arabidopsis thaliana}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-98678}, school = {Universit{\"a}t Potsdam}, pages = {xi, 182}, year = {2016}, abstract = {F{\"u}r alle Organismen ist die Aufrechterhaltung ihres energetischen Gleichgewichts unter fluktuierenden Umweltbedingungen lebensnotwendig. In Eukaryoten steuern evolution{\"a}r konservierte Proteinkinasen, die in Pflanzen als SNF1-RELATED PROTEIN KINASE1 (SnRK1) bezeichnet werden, die Adaption an Stresssignale aus der Umwelt und an die Limitierung von N{\"a}hrstoffen und zellul{\"a}rer Energie. Die Aktivierung von SnRK1 bedingt eine umfangreiche transkriptionelle Umprogrammierung, die allgemein zu einer Repression energiekonsumierender Prozesse wie beispielsweise Zellteilung und Proteinbiosynthese und zu einer Induktion energieerzeugender, katabolischer Stoffwechselwege f{\"u}hrt. Wie unterschiedliche Signale zu einer generellen sowie teilweise gewebe- und stressspezifischen SnRK1-vermittelten Antwort f{\"u}hren ist bisher noch nicht ausreichend gekl{\"a}rt, auch weil bislang nur wenige Komponenten der SnRK1-Signaltransduktion identifiziert wurden. In dieser Arbeit konnte ein Protein-Protein-Interaktionsnetzwerk um die SnRK1αUntereinheiten aus Arabidopsis AKIN10/AKIN11 etabliert werden. Dadurch wurden zun{\"a}chst Mitglieder der pflanzenspezifischen DUF581-Proteinfamilie als Interaktionspartner der SnRK1α-Untereinheiten identifiziert. Diese Proteine sind {\"u}ber ihre konservierte DUF581Dom{\"a}ne, in der ein Zinkfinger-Motiv lokalisiert ist, f{\"a}hig mit AKIN10/AKIN11 zu interagieren. In planta Ko-Expressionsanalysen zeigten, dass die DUF581-Proteine eine Verschiebung der nucleo-cytoplasmatischen Lokalisierung von AKIN10 hin zu einer nahezu ausschließlichen zellkernspezifischen Lokalisierung beg{\"u}nstigen sowie die Ko-Lokalisierung von AKIN10 und DUF581-Proteinen im Nucleus. In Bimolekularen Fluoreszenzkomplementations-Analysen konnte die zellkernspezifische Interaktion von DUF581-Proteinen mit SnRK1α-Untereinheiten in planta best{\"a}tigt werden. Außerhalb der DUF581-Dom{\"a}ne weisen die Proteine einander keine große Sequenz{\"a}hnlichkeit auf. Aufgrund ihrer F{\"a}higkeit mit SnRK1 zu interagieren, dem Fehlen von SnRK1Phosphorylierungsmotiven sowie ihrer untereinander sehr variabler gewebs-, entwicklungs- und stimulusspezifischer Expression wurde f{\"u}r DUF581-Proteine eine Funktion als Adaptoren postuliert, die unter bestimmten physiologischen Bedingungen spezifische Substratproteine in den SnRK1-Komplex rekrutieren. Auf diese Weise k{\"o}nnten DUF581Proteine die Interaktion von SnRK1 mit deren Zielproteinen modifizieren und eine Feinjustierung der SnRK1-Signalweiterleitung erm{\"o}glichen. Durch weiterf{\"u}hrende Interaktionsstudien konnten DUF581-interagierende Proteine darunter Transkriptionsfaktoren, Proteinkinasen sowie regulatorische Proteine gefunden werden, die teilweise ebenfalls Wechselwirkungen mit SnRK1α-Untereinheiten aufzeigten. Im Rahmen dieser Arbeit wurde eines dieser Proteine f{\"u}r das eine Beteiligung an der SnRK1Signalweiterleitung als Transkriptionsregulator vermutet wurde n{\"a}her charakterisiert. STKR1 (STOREKEEPER RELATED 1), ein spezifischer Interaktionspartner von DUF581-18, geh{\"o}rt zu einer pflanzenspezifischen Leucin-Zipper-Transkriptionsfaktorfamilie und interagiert in Hefe sowie in planta mit SnRK1. Die zellkernspezifische Interaktion von STKR1 und AKIN10 in Pflanzen unterst{\"u}tzt die Vermutung der kooperativen Regulation von Zielgenen. Weiterhin stabilisierte die Anwesenheit von AKIN10 die Proteingehalte von STKR1, das wahrscheinlich {\"u}ber das 26S Proteasom abgebaut wird. Da es sich bei STKR1 um ein Phosphoprotein mit SnRK1-Phosphorylierungsmotiv handelt, stellt es sehr wahrscheinlich ein SnRK1-Substrat dar. Allerdings konnte eine SnRK1-vermittelte Phosphorylierung von STKR1 in dieser Arbeit nicht gezeigt werden. Der Verlust von einer Phosphorylierungsstelle beeinflusste die Homo- und Heterodimerisierungsf{\"a}higkeit von STKR1 in Hefeinteraktionsstudien, wodurch eine erh{\"o}hte Spezifit{\"a}t der Zielgenregulation erm{\"o}glicht werden k{\"o}nnte. Außerdem wurden Arabidopsis-Pflanzen mit einer ver{\"a}nderten STKR1-Expression ph{\"a}notypisch, physiologisch und molekularbiologisch charakterisiert. W{\"a}hrend der Verlust der STKR1-Expression zu Pflanzen f{\"u}hrte, die sich kaum von Wildtyp-Pflanzen unterschieden, bedingte die konstitutive {\"U}berexpression von STKR1 ein stark vermindertes Pflanzenwachstum sowie Entwicklungsverz{\"o}gerungen hinsichtlich der Bl{\"u}hinduktion und Seneszenz {\"a}hnlich wie sie auch bei SnRK1α-{\"U}berexpression beschrieben wurden. Pflanzen dieser Linien waren nicht in der Lage Anthocyane zu akkumulieren und enthielten geringere Gehalte an Chlorophyll und Carotinoiden. Neben einem erh{\"o}hten n{\"a}chtlichen St{\"a}rkeumsatz waren die Pflanzen durch geringere Saccharosegehalte im Vergleich zum Wildtyp gekennzeichnet. Eine Transkriptomanalyse ergab, dass in den STKR1-{\"u}berexprimierenden Pflanzen unter Energiemangelbedingungen, hervorgerufen durch eine verl{\"a}ngerte Dunkelphase, eine gr{\"o}ßere Anzahl an Genen im Vergleich zum Wildtyp differentiell reguliert war als w{\"a}hrend der Lichtphase. Dies spricht f{\"u}r eine Beteiligung von STKR1 an Prozessen, die w{\"a}hrend der verl{\"a}ngerten Dunkelphase aktiv sind. Ein solcher ist beispielsweise die SnRK1-Signaltransduktion, die unter energetischem Stress aktiviert wird. Die STKR1{\"U}berexpression f{\"u}hrte zudem zu einer verst{\"a}rkten transkriptionellen Induktion von Abwehrassoziierten Genen sowie NAC- und WRKY-Transkriptionsfaktoren nach verl{\"a}ngerter Dunkelphase. Die Transkriptomdaten deuteten auf eine stimulusunabh{\"a}ngige Induktion von Abwehrprozessen hin und konnten eine Erkl{\"a}rung f{\"u}r die ph{\"a}notypischen und physiologischen Auff{\"a}lligkeiten der STKR1-{\"U}berexprimierer liefern.}, language = {de} } @phdthesis{Kloss2016, author = {Kloß, Lena}, title = {The link between genetic diversity and species diversity}, school = {Universit{\"a}t Potsdam}, pages = {109}, year = {2016}, language = {en} } @phdthesis{Bolger2016, author = {Bolger, Anthony}, title = {Sequencing the Genome of the stress-tolerant wild tomato Solanum pennellii and Novel Algorithms motivated thereby}, school = {Universit{\"a}t Potsdam}, pages = {143}, year = {2016}, language = {en} } @phdthesis{Dotzek2016, author = {Dotzek, Jana}, title = {Mitochondria in the genus Oenothera - Non-Mendelian inheritance patterns, in vitro structure and evolutionary dynamics}, school = {Universit{\"a}t Potsdam}, pages = {134}, year = {2016}, language = {en} } @article{KlauschiesVasseurGaedke2016, author = {Klauschies, Toni and Vasseur, David A. and Gaedke, Ursula}, title = {Trait adaptation promotes species coexistence in diverse predator and prey communities}, series = {Ecology and evolution}, journal = {Ecology and evolution}, publisher = {John Wiley \& Sons, Inc.}, issn = {2045-7758}, doi = {10.1002/ece3.2172}, pages = {19}, year = {2016}, abstract = {Species can adjust their traits in response to selection which may strongly influence species coexistence. Nevertheless, current theory mainly assumes distinct and time-invariant trait values. We examined the combined effects of the range and the speed of trait adaptation on species coexistence using an innovative multispecies predator-prey model. It allows for temporal trait changes of all predator and prey species and thus simultaneous coadaptation within and among trophic levels. We show that very small or slow trait adaptation did not facilitate coexistence because the stabilizing niche differences were not sufficient to offset the fitness differences. In contrast, sufficiently large and fast trait adaptation jointly promoted stable or neutrally stable species coexistence. Continuous trait adjustments in response to selection enabled a temporally variable convergence and divergence of species traits; that is, species became temporally more similar (neutral theory) or dissimilar (niche theory) depending on the selection pressure, resulting over time in a balance between niche differences stabilizing coexistence and fitness differences promoting competitive exclusion. Furthermore, coadaptation allowed prey and predator species to cluster into different functional groups. This equalized the fitness of similar species while maintaining sufficient niche differences among functionally different species delaying or preventing competitive exclusion. In contrast to pre- vious studies, the emergent feedback between biomass and trait dynamics enabled supersaturated coexistence for a broad range of potential trait adaptation and parameters. We conclude that accounting for trait adaptation may explain stable and supersaturated species coexistence for a broad range of environmental conditions in natural systems when the absence of such adaptive changes would preclude it. Small trait changes, coincident with those that may occur within many natural populations, greatly enlarged the number of coexisting species.}, language = {en} } @misc{KlauschiesVasseurGaedke2016, author = {Klauschies, Toni and Vasseur, David A. and Gaedke, Ursula}, title = {Trait adaptation promotes species coexistence in diverse predator and prey communities}, issn = {1866-8372}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-91498}, pages = {19}, year = {2016}, abstract = {Species can adjust their traits in response to selection which may strongly influence species coexistence. Nevertheless, current theory mainly assumes distinct and time-invariant trait values. We examined the combined effects of the range and the speed of trait adaptation on species coexistence using an innovative multispecies predator-prey model. It allows for temporal trait changes of all predator and prey species and thus simultaneous coadaptation within and among trophic levels. We show that very small or slow trait adaptation did not facilitate coexistence because the stabilizing niche differences were not sufficient to offset the fitness differences. In contrast, sufficiently large and fast trait adaptation jointly promoted stable or neutrally stable species coexistence. Continuous trait adjustments in response to selection enabled a temporally variable convergence and divergence of species traits; that is, species became temporally more similar (neutral theory) or dissimilar (niche theory) depending on the selection pressure, resulting over time in a balance between niche differences stabilizing coexistence and fitness differences promoting competitive exclusion. Furthermore, coadaptation allowed prey and predator species to cluster into different functional groups. This equalized the fitness of similar species while maintaining sufficient niche differences among functionally different species delaying or preventing competitive exclusion. In contrast to previous studies, the emergent feedback between biomass and trait dynamics enabled supersaturated coexistence for a broad range of potential trait adaptation and parameters. We conclude that accounting for trait adaptation may explain stable and supersaturated species coexistence for a broad range of environmental conditions in natural systems when the absence of such adaptive changes would preclude it. Small trait changes, coincident with those that may occur within many natural populations, greatly enlarged the number of coexisting species.}, language = {en} } @phdthesis{Beltran2016, author = {Beltran, Juan Camilo Moreno}, title = {Characterization of the Clp protease complex and identification of putative substrates in N. tabacum}, school = {Universit{\"a}t Potsdam}, year = {2016}, language = {en} }