TY - JOUR A1 - Anders, Kenneth A1 - Beier, Wolfgang A1 - Brunk, Ingo A1 - Burkart, Bettina A1 - Mrzljak, Anders A1 - Oehlschläger, Susanne T1 - Freie Sukzession und Offenlandmanagement Y1 - 2004 SN - 3-540-22449-1 ER - TY - JOUR A1 - Amen, Rahma A1 - Nagel, Rebecca A1 - Hedt, Maximilian A1 - Kirschbaum, Frank A1 - Tiedemann, Ralph T1 - Morphological differentiation in African weakly electric fish (genus Campylomormyrus) relates to substrate preferences JF - Evolutionary Ecology N2 - Under an ecological speciation scenario, the radiation of African weakly electric fish (genus Campylomormyrus) is caused by an adaptation to different food sources, associated with diversification of the electric organ discharge (EOD). This study experimentally investigates a phenotype-environment correlation to further support this scenario. Our behavioural experiments showed that three sympatric Campylomormyrus species with significantly divergent snout morphology differentially react to variation in substrate structure. While the short snout species (C. tamandua) exhibits preference to sandy substrate, the long snout species (C. rhynchophorus) significantly prefers a stone substrate for feeding. A third species with intermediate snout size (C. compressirostris) does not exhibit any substrate preference. This preference is matched with the observation that long-snouted specimens probe deeper into the stone substrate, presumably enabling them to reach prey more distant to the substrate surface. These findings suggest that the diverse feeding apparatus in the genus Campylomormyrus may have evolved in adaptation to specific microhabitats, i.e., substrate structures where these fish forage. Whether the parallel divergence in EOD is functionally related to this adaptation or solely serves as a prezygotic isolation mechanism remains to be elucidated. KW - ecological speciation KW - feeding behaviour KW - electric fish KW - trophic apparatus KW - evolutionary ecology Y1 - 2020 U6 - https://doi.org/10.1007/s10682-020-10043-3 SN - 0269-7653 SN - 1573-8477 VL - 34 IS - 3 SP - 427 EP - 437 PB - Springer Science CY - Dordrecht ER - TY - GEN A1 - Amen, Rahma A1 - Nagel, Rebecca A1 - Hedt, Maximilian A1 - Kirschbaum, Frank A1 - Tiedemann, Ralph T1 - Morphological differentiation in African weakly electric fish (genus Campylomormyrus) relates to substrate preferences T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Under an ecological speciation scenario, the radiation of African weakly electric fish (genus Campylomormyrus) is caused by an adaptation to different food sources, associated with diversification of the electric organ discharge (EOD). This study experimentally investigates a phenotype-environment correlation to further support this scenario. Our behavioural experiments showed that three sympatric Campylomormyrus species with significantly divergent snout morphology differentially react to variation in substrate structure. While the short snout species (C. tamandua) exhibits preference to sandy substrate, the long snout species (C. rhynchophorus) significantly prefers a stone substrate for feeding. A third species with intermediate snout size (C. compressirostris) does not exhibit any substrate preference. This preference is matched with the observation that long-snouted specimens probe deeper into the stone substrate, presumably enabling them to reach prey more distant to the substrate surface. These findings suggest that the diverse feeding apparatus in the genus Campylomormyrus may have evolved in adaptation to specific microhabitats, i.e., substrate structures where these fish forage. Whether the parallel divergence in EOD is functionally related to this adaptation or solely serves as a prezygotic isolation mechanism remains to be elucidated. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1416 KW - ecological speciation KW - feeding behaviour KW - electric fish KW - trophic apparatus KW - evolutionary ecology Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-518714 SN - 1866-8372 IS - 3 ER - TY - THES A1 - Amen, Rahma T1 - Adaptive radiation in African weakly electric fish genus Campylomormyrus BT - a behavior, ecological and morphological perspective N2 - The African weakly electric fish genus Campylomormyrus includes 15 described species mostly native to the Congo River and its tributaries. They are considered sympatric species, because their distribution area overlaps. These species generate species-specific electric organ discharges (EODs) varying in waveform characteristics, including duration, polarity, and phase number. They exhibit also pronounced divergence in their snout, i.e. the length, thickness, and curvature. The diversifications in these two phenotypical traits (EOD and snout) have been proposed as key factors promoting adaptive radiation in Campylomormyrus. The role of EODs as a pre-zygotic isolation mechanism driving sympatric speciation by promoting assortative mating has been examined using behavioral, genetical, and histological approaches. However, the evolutionary effects of the snout morphology and its link to species divergence have not been closely examined. Hence, the main objective of this study is to investigate the effect of snout morphology diversification and its correlated EOD to better understand their sympatric speciation and evolutionary drivers. Moreover, I aim to utilize the intragenus and intergenus hybrids of Campylomormyrus to better understand trait divergence as well as underlying molecular/genetic mechanisms involved in the radiation scenario. To this end, I utilized three different approaches: feeding behavior analysis, diet assessment, and geometric morphometrics analysis. I performed feeding behavior experiments to evaluate the concept of the phenotype-environment correlation by testing whether Campylomormyrus species show substrate preferences. The behavioral experiments showed that the short snout species exhibits preference to sandy substrate, the long snout species prefers a stone substrate, and the species with intermediate snout size does not exhibit any substrate preference. The experiments suggest that the diverse feeding apparatus in the genus Campylomormyrus may have evolved in adaptation to their microhabitats. I also performed diet assessments of sympatric Campylomormyrus species and a sister genus species (Gnathonemus petersii) with markedly different snout morphologies and EOD using NGS-based DNA metabarcoding of their stomach contents. The diet of each species was documented showing that aquatic insects such as dipterans, coleopterans and trichopterans represent the major diet component. The results showed also that all species are able to exploit diverse food niches in their habitats. However, comparing the diet overlap indices showed that different snout morphologies and the associated divergence in the EOD translated into different prey spectra. These results further support the idea that the EOD could be a ‘magic trait’ triggering both adaptation and reproductive isolation. Geometric morphometrics method was also used to compare the phenotypical shape traits of the F1 intragenus (Campylomormyrus) and intergenus (Campylomormyrus species and Gnathonemus petersii) hybrids relative to their parents. The hybrids of these species were well separated based on the morphological traits, however the hybrid phenotypic traits were closer to the short-snouted species. In addition, the likelihood that the short snout expressed in the hybrids increases with increasing the genetic distance of the parental species. The results confirmed that additive effects produce intermediate phenotypes in F1-hybrids. It seems, therefore, that morphological shape traits in hybrids, unlike the physiological traits, were not expressed straightforward. KW - adaptive radiation KW - ecological speciation KW - African weakly electric fish KW - trophic apparatus KW - DNA metabarcoding KW - geometric morphometric Y1 - 2023 ER - TY - JOUR A1 - Ambarli, Hüseyin A1 - Mengüllüoğlu, Deniz A1 - Fickel, Jörns A1 - Förster, Daniel W. T1 - Hotel AMANO Grand Central of brown bears in southwest Asia JF - PeerJ N2 - Genetic studies of the Eurasian brown bear (Ursus arctos) have so far focused on populations from Europe and North America, although the largest distribution area of brown bears is in Asia. In this study, we reveal population genetic parameters for the brown bear population inhabiting the Grand Kackar Mountains (GKM) in the north east of Turkey, western Lesser Caucasus. Using both hair (N = 147) and tissue samples (N = 7) collected between 2008 and 2014, we found substantial levels of genetic variation (10 microsatellite loci). Bear samples (hair) taken from rubbing trees worked better for genotyping than those from power poles, regardless of the year collected. Genotyping also revealed that bears moved between habitat patches, despite ongoing massive habitat alterations and the creation of large water reservoirs. This population has the potential to serve as a genetic reserve for future reintroduction in the Middle East. Due to the importance of the GKM population for on-going and future conservation actions, the impacts of habitat alterations in the region ought to be minimized; e.g., by establishing green bridges or corridors over reservoirs and major roads to maintain habitat connectivity and gene flow among populations in the Lesser Caucasus. KW - Ursus arctos KW - Microsatellite KW - Conservation KW - Anatolia KW - Isolation KW - Source population KW - Noninvasive sampling KW - Rubbing tree KW - Turkey Y1 - 2018 U6 - https://doi.org/10.7717/peerj.5660 SN - 2167-8359 VL - 6 PB - PeerJ Inc. CY - London ER - TY - JOUR A1 - Amalfitano, Stefano A1 - Corno, Gianluca A1 - Eckert, Ester A1 - Fazi, Stefano A1 - Ninio, Shira A1 - Callieri, Cristiana A1 - Grossart, Hans-Peter A1 - Eckert, Werner T1 - Tracing particulate matter and associated microorganisms in freshwaters JF - Hydrobiologia : acta hydrobiologica, hydrographica, limnologica et protistologica N2 - Sediment resuspension represents a key process in all natural aquatic systems, owing to its role in nutrient cycling and transport of potential contaminants. Although suspended solids are generally accepted as an important quality parameter, current monitoring programs cover quantitative aspects only. Established methodologies do not provide information on origin, fate, and risks associated with uncontrolled inputs of solids in waters. Here we discuss the analytical approaches to assess the occurrence and ecological relevance of resuspended particulate matter in freshwaters, with a focus on the dynamics of associated contaminants and microorganisms. Triggered by the identification of specific physical-chemical traits and community structure of particle-associated microorganisms, recent findings suggest that a quantitative determination of microorganisms can be reasonably used to trace the origin of particulate matter by means of nucleic acid-based assays in different aquatic systems. KW - Total suspended solids KW - Resuspended particulate KW - Turbidity KW - Sediment traps KW - Particle-associated microorganisms KW - Pathogens Y1 - 2017 U6 - https://doi.org/10.1007/s10750-017-3260-x SN - 0018-8158 SN - 1573-5117 VL - 800 SP - 145 EP - 154 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Altmann, Thomas A1 - von Groll, Uritza A1 - Berger, Dieter T1 - The subtilisin-like serine protease SDD1 mediates cell-cell signaling during Arabidopsis stomatal development Y1 - 2002 ER - TY - JOUR A1 - Altmann, Thomas A1 - von Groll, Uritza T1 - Stomatal cell biology Y1 - 2003 ER - TY - JOUR A1 - Altmann, Thomas A1 - Udvardi, M. K. A1 - Essigmann, B. A1 - Colebatch, G. A1 - Kloska, Sebastian A1 - Smith, P. A1 - Trevaskis, B. T1 - Lotus japonicus functional genomics : cDNA microarray analysis uncovers novel nodulins Y1 - 2002 SN - 0-85199-591-8 ER - TY - JOUR A1 - Altmann, Thomas A1 - Törjek, Otto A1 - Berger, Dieter A1 - Meyer, Rhonda C. A1 - Müssig, Carsten A1 - Schmidt, K. J. A1 - Sorensen, T. R. A1 - Weisshaar, Bernd A1 - Olds-Mitchell, T. T1 - Establishment of a high-efficiency SNP-based framework marker set for Arabidopsis Y1 - 2003 ER - TY - JOUR A1 - Altmann, Thomas A1 - Thimm, O. A1 - Essigmann, B. A1 - Kloska, Sebastian A1 - Buckhout, Thomas J. T1 - Response of arabidopsis to iron deficiency stress as revealed by microarray analysis Y1 - 2001 ER - TY - JOUR A1 - Altmann, Thomas A1 - Taylor, Janet A1 - King, Ross. D. A1 - Fiehn, Oliver T1 - Application of metabolomics to plant genotype discrimination using statistics and machine learning Y1 - 2003 ER - TY - JOUR A1 - Altmann, Thomas A1 - Schmid, K. J. A1 - Sörensen, Rossleff T. A1 - Stracke, R. A1 - Törjek, Otto A1 - Mitchel-Olds, T. A1 - Weisshaar, Bernd T1 - Large-scale identification and analysis of genome-wide single-nucleotide polymorphisms for mapping in Arabidopsis thaliana Y1 - 2003 ER - TY - JOUR A1 - Altmann, Thomas A1 - Schlüter, U. A1 - Muschak, M. A1 - Berger, Dieter T1 - Photosynthetic performance of an Arabidopsis mutant with elevated stomatal density (sdd1-1) under different light regimes Y1 - 2003 ER - TY - JOUR A1 - Altmann, Thomas A1 - Schlüter, U. A1 - Köpke, D. A1 - Müssig, Carsten T1 - Analysis of carbohydrate metabolism of CPD antisense plants and the brassinosteroid-deficient cbb1 mutant Y1 - 2002 ER - TY - JOUR A1 - Altmann, Thomas A1 - Narang, R. A. T1 - Phosphate accquisition heterosis in Arabidopsis thaliana : a morphological and physiological analysis Y1 - 2001 ER - TY - JOUR A1 - Altmann, Thomas A1 - Müssig, Carsten A1 - Fischer, Sabine T1 - Brassinosteroid-regulated gene expression Y1 - 2002 ER - TY - JOUR A1 - Altmann, Thomas A1 - Müssig, Carsten T1 - Brassinosteroid signaling in plants Y1 - 2001 ER - TY - JOUR A1 - Altmann, Thomas A1 - Koßmann, Jens T1 - Photosynthesis and primary metabolism Y1 - 2001 SN - 1360-1385 ER - TY - JOUR A1 - Altmann, Thomas A1 - Fiehn, Oliver A1 - Kloska, Sebastian T1 - Integrated studies on plant biology using multiparallel techniques Y1 - 2001 ER -