TY - JOUR A1 - Ruzanski, Christian A1 - Smirnova, Julia A1 - Rejzek, Martin A1 - Cockburn, Darrell A1 - Pedersen, Henriette L. A1 - Pike, Marilyn A1 - Willats, William G. T. A1 - Svensson, Birte A1 - Steup, Martin A1 - Ebenhöh, Oliver A1 - Smith, Alison M. A1 - Field, Robert A. T1 - A bacterial glucanotransferase can replace the complex maltose metabolism required for starch to sucrose conversion in leaves at night JF - The journal of biological chemistry N2 - Controlled conversion of leaf starch to sucrose at night is essential for the normal growth of Arabidopsis. The conversion involves the cytosolic metabolism of maltose to hexose phosphates via an unusual, multidomain protein with 4-glucanotransferase activity, DPE2, believed to transfer glucosyl moieties to a complex heteroglycan prior to their conversion to hexose phosphate via a cytosolic phosphorylase. The significance of this complex pathway is unclear; conversion of maltose to hexose phosphate in bacteria proceeds via a more typical 4-glucanotransferase that does not require a heteroglycan acceptor. It has recently been suggested that DPE2 generates a heterogeneous series of terminal glucan chains on the heteroglycan that acts as a glucosyl buffer to ensure a constant rate of sucrose synthesis in the leaf at night. Alternatively, DPE2 and/or the heteroglycan may have specific properties important for their function in the plant. To distinguish between these ideas, we compared the properties of DPE2 with those of the Escherichia coli glucanotransferase MalQ. We found that MalQ cannot use the plant heteroglycan as an acceptor for glucosyl transfer. However, experimental and modeling approaches suggested that it can potentially generate a glucosyl buffer between maltose and hexose phosphate because, unlike DPE2, it can generate polydisperse malto-oligosaccharides from maltose. Consistent with this suggestion, MalQ is capable of restoring an essentially wild-type phenotype when expressed in mutant Arabidopsis plants lacking DPE2. In light of these findings, we discuss the possible evolutionary origins of the complex DPE2-heteroglycan pathway. KW - Carbohydrate Metabolism KW - Computer Modeling KW - Metabolic Regulation KW - Oligosaccharide KW - Plant Biochemistry KW - Glucanotransferase KW - Leaf Cell KW - Maltose Metabolism KW - Starch Degradation Y1 - 2013 U6 - https://doi.org/10.1074/jbc.M113.497867 SN - 0021-9258 SN - 1083-351X VL - 288 IS - 40 SP - 28581 EP - 28598 PB - American Society for Biochemistry and Molecular Biology CY - Bethesda ER - TY - JOUR A1 - Badalyan, Artavazd A1 - Neumann-Schaal, Meina A1 - Leimkühler, Silke A1 - Wollenberger, Ursula T1 - A Biosensor for aromatic aldehydes comprising the mediator dependent PaoABC-Aldehyde oxidoreductase JF - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis N2 - A novel aldehyde oxidoreductase (PaoABC) from Escherichia coli was utilized for the development of an oxygen insensitive biosensor for benzaldehyde. The enzyme was immobilized in polyvinyl alcohol and currents were measured for aldehyde oxidation with different one and two electron mediators with the highest sensitivity for benzaldehyde in the presence of hexacyanoferrate(III). The benzaldehyde biosensor was optimized with respect to mediator concentration, enzyme loading and pH using potassium hexacyanoferrate(III). The linear measuring range is between 0.5200 mu M benzaldehyde. In correspondence with the substrate selectivity of the enzyme in solution the biosensor revealed a preference for aromatic aldehydes and less effective conversion of aliphatic aldehydes. The biosensor is oxygen independent, which is a particularly attractive feature for application. The biosensor can be applied to detect contaminations with benzaldehyde in solvents such as benzyl alcohol, where traces of benzaldehyde in benzyl alcohol down to 0.0042?% can be detected. KW - Aldehyde oxidoreductase KW - Benzaldehyde KW - Biosensor KW - Aromatic aldehydes KW - Molybdenum cofactor Y1 - 2013 U6 - https://doi.org/10.1002/elan.201200362 SN - 1040-0397 VL - 25 IS - 1 SP - 101 EP - 108 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Allan, Eric A1 - Weisser, Wolfgang W. A1 - Fischer, Markus A1 - Schulze, Ernst-Detlef A1 - Weigelt, Alexandra A1 - Roscher, Christiane A1 - Baade, Jussi A1 - Barnard, Romain L. A1 - Bessler, Holger A1 - Buchmann, Nina A1 - Ebeling, Anne A1 - Eisenhauer, Nico A1 - Engels, Christof A1 - Fergus, Alexander J. F. A1 - Gleixner, Gerd A1 - Gubsch, Marlen A1 - Halle, Stefan A1 - Klein, Alexandra-Maria A1 - Kertscher, Ilona A1 - Kuu, Annely A1 - Lange, Markus A1 - Le Roux, Xavier A1 - Meyer, Sebastian T. A1 - Migunova, Varvara D. A1 - Milcu, Alexandru A1 - Niklaus, Pascal A. A1 - Oelmann, Yvonne A1 - Pasalic, Esther A1 - Petermann, Jana S. A1 - Poly, Franck A1 - Rottstock, Tanja A1 - Sabais, Alexander C. W. A1 - Scherber, Christoph A1 - Scherer-Lorenzen, Michael A1 - Scheu, Stefan A1 - Steinbeiss, Sibylle A1 - Schwichtenberg, Guido A1 - Temperton, Vicky A1 - Tscharntke, Teja A1 - Voigt, Winfried A1 - Wilcke, Wolfgang A1 - Wirth, Christian A1 - Schmid, Bernhard T1 - A comparison of the strength of biodiversity effects across multiple functions JF - Oecologia N2 - In order to predict which ecosystem functions are most at risk from biodiversity loss, meta-analyses have generalised results from biodiversity experiments over different sites and ecosystem types. In contrast, comparing the strength of biodiversity effects across a large number of ecosystem processes measured in a single experiment permits more direct comparisons. Here, we present an analysis of 418 separate measures of 38 ecosystem processes. Overall, 45 % of processes were significantly affected by plant species richness, suggesting that, while diversity affects a large number of processes not all respond to biodiversity. We therefore compared the strength of plant diversity effects between different categories of ecosystem processes, grouping processes according to the year of measurement, their biogeochemical cycle, trophic level and compartment (above- or belowground) and according to whether they were measures of biodiversity or other ecosystem processes, biotic or abiotic and static or dynamic. Overall, and for several individual processes, we found that biodiversity effects became stronger over time. Measures of the carbon cycle were also affected more strongly by plant species richness than were the measures associated with the nitrogen cycle. Further, we found greater plant species richness effects on measures of biodiversity than on other processes. The differential effects of plant diversity on the various types of ecosystem processes indicate that future research and political effort should shift from a general debate about whether biodiversity loss impairs ecosystem functions to focussing on the specific functions of interest and ways to preserve them individually or in combination. KW - Bottom-up effects KW - Carbon cycling KW - Ecological synthesis KW - Ecosystem processes KW - Grasslands KW - Jena experiment KW - Nitrogen cycling Y1 - 2013 U6 - https://doi.org/10.1007/s00442-012-2589-0 SN - 0029-8549 VL - 173 IS - 1 SP - 223 EP - 237 PB - Springer CY - New York ER - TY - JOUR A1 - Bukovinszky, Tibor A1 - Helmsing, Nico R. A1 - Grau, R. A. A1 - Bakker, Elisabeth S. A1 - Bezemer, T. Martijn A1 - Vos, Matthijs A1 - Uittenhout, H. A1 - Verschoor, A. M. T1 - A device to study the behavioral responses of zooplankton to food quality and quantity JF - Journal of insect behavior N2 - In order to explore the behavioral mechanisms underlying aggregation of foragers on local resource patches, it is necessary to manipulate the location, quality and quantity of food patches. This requires careful control over the conditions in the foraging arena, which may be a challenging task in the case of aquatic resource-consumer systems, like that of freshwater zooplankton feeding on suspended algal cells. We present an experimental tool designed to aid behavioral ecologists in exploring the consequences of resource characteristics for zooplankton aggregation behavior and movement decisions under conditions where the boundaries and characteristics (quantity and quality) of food patches can be standardized. The aggregation behavior of Daphnia magna and D. galeata x hyalina was tested in relation to i) the presence or absence of food or ii) food quality, where algae of high or low nutrient (phosphorus) content were offered in distinct patches. Individuals of both Daphnia species chose tubes containing food patches and D. galeata x hyalina also showed a preference towards food patches of high nutrient content. We discuss how the described equipment complements other behavioral approaches providing a useful tool to understand animal foraging decisions in environments with heterogeneous resource distributions. KW - Foraging behavior KW - behavioral choice KW - food preference KW - Daphnia KW - flow-through vessel Y1 - 2013 U6 - https://doi.org/10.1007/s10905-012-9366-0 SN - 0892-7553 VL - 26 IS - 4 SP - 453 EP - 465 PB - Springer CY - New York ER - TY - JOUR A1 - Tikhonenko, Irina A1 - Magidson, Valentin A1 - Gräf, Ralph A1 - Khodjakov, Alexey A1 - Koonce, Michael P. T1 - A kinesin-mediated mechanism that couples centrosomes to nuclei JF - Cellular and molecular life sciences N2 - The M-type kinesin isoform, Kif9, has recently been implicated in maintaining a physical connection between the centrosome and nucleus in Dictyostelium discoideum. However, the mechanism by which Kif9 functions to link these two organelles remains obscure. Here we demonstrate that the Kif9 protein is localized to the nuclear envelope and is concentrated in the region underlying the centrosome point of attachment. Nuclear anchorage appears mediated through a specialized transmembrane domain located in the carboxyl terminus. Kif9 interacts with microtubules in in vitro binding assays and effects an endwise depolymerization of the polymer. These results suggest a model whereby Kif9 is anchored to the nucleus and generates a pulling force that reels the centrosome up against the nucleus. This is a novel activity for a kinesin motor, one important for progression of cells into mitosis and to ensure centrosome-nuclear parity in a multinuclear environment. KW - Centrosome KW - Kinesin KW - Microtubule KW - Dictyostelium Y1 - 2013 U6 - https://doi.org/10.1007/s00018-012-1205-0 SN - 1420-682X VL - 70 IS - 7 SP - 1285 EP - 1296 PB - Springer CY - Basel ER - TY - THES A1 - Wang, Ting T1 - A novel R2R3 MYB-like transcription factor regulates ABA mediated stress response and leaf growth in Arabidopsis Y1 - 2013 CY - Potsdam ER - TY - JOUR A1 - Fiorentino, V. A1 - Manganelli, Giuseppe A1 - Giusti, Folco A1 - Tiedemann, Ralph A1 - Ketmaier, Valerino T1 - A question of time the land snail Murella muralis (Gastropoda: Pulmonata) reveals constraints on past ecological speciation JF - Molecular ecology N2 - The lively debate about speciation currently focuses on the relative importance of factors driving population differentiation. While many studies are increasingly producing results on the importance of selection, little is known about the interaction between drift and selection. Moreover, there is still little knowledge on the spatial-temporal scales at which speciation occurs, that is, arrangement of habitat patches, abruptness of habitat transitions, climate and habitat changes interacting with selective forces. To investigate these questions, we quantified variation on a fine geographical scale analysing morphological (shell) and genetic data sets coupled with environmental data in the land snail Murella muralis, endemic to the Mediterranean island of Sicily. Analysis of a fragment of the mitochondrial DNA cytochrome oxidase I gene (COI) and eight nuclear microsatellite loci showed that genetic variation is highly structured at a very fine spatial scale by local palaeogeographical events and historical population dynamics. Molecular clock estimates, calibrated here specifically for Tyrrhenian land snails, provided a framework of palaeogeographical events responsible for the observed geographical variations and migration routes. Finally, we showed for the first time well-documented lines of evidence of selection in the past, which explains divergence of land snail shell shapes. We suggest that time and palaeogeographical history acted as constraints in the progress along the ecological speciation continuum. Our study shows that testing for correlation among palaeogeography, morphology and genetic data on a fine geographical scale provides information fundamental for a detailed understanding of ecological speciation processes. KW - allopatry KW - cytochrome oxidase I gene KW - ecological speciation KW - land snails KW - microsatellites KW - Murella Y1 - 2013 U6 - https://doi.org/10.1111/mec.12107 SN - 0962-1083 SN - 1365-294X VL - 22 IS - 1 SP - 170 EP - 186 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Brothers, Soren M. A1 - Hilt, Sabine A1 - Attermeyer, Katrin A1 - Grossart, Hans-Peter A1 - Kosten, Sarian A1 - Lischke, Betty A1 - Mehner, Thomas A1 - Meyer, Nils A1 - Scharnweber, Inga Kristin A1 - Köhler, Jan T1 - A regime shift from macrophyte to phytoplankton dominance enhances carbon burial in a shallow, eutrophic lake JF - Ecosphere : the magazine of the International Ecology University N2 - Ecological regime shifts and carbon cycling in aquatic systems have both been subject to increasing attention in recent years, yet the direct connection between these topics has remained poorly understood. A four-fold increase in sedimentation rates was observed within the past 50 years in a shallow eutrophic lake with no surface in-or outflows. This change coincided with an ecological regime shift involving the complete loss of submerged macrophytes, leading to a more turbid, phytoplankton-dominated state. To determine whether the increase in carbon (C) burial resulted from a comprehensive transformation of C cycling pathways in parallel to this regime shift, we compared the annual C balances (mass balance and ecosystem budget) of this turbid lake to a similar nearby lake with submerged macrophytes, a higher transparency, and similar nutrient concentrations. C balances indicated that roughly 80% of the C input was permanently buried in the turbid lake sediments, compared to 40% in the clearer macrophyte-dominated lake. This was due to a higher measured C burial efficiency in the turbid lake, which could be explained by lower benthic C mineralization rates. These lower mineralization rates were associated with a decrease in benthic oxygen availability coinciding with the loss of submerged macrophytes. In contrast to previous assumptions that a regime shift to phytoplankton dominance decreases lake heterotrophy by boosting whole-lake primary production, our results suggest that an equivalent net metabolic shift may also result from lower C mineralization rates in a shallow, turbid lake. The widespread occurrence of such shifts may thus fundamentally alter the role of shallow lakes in the global C cycle, away from channeling terrestrial C to the atmosphere and towards burying an increasing amount of C. KW - calcite precipitation KW - CO2 emissions KW - global carbon cycle KW - metabolism KW - regime shift KW - sedimentation KW - submerged macrophytes KW - temperate zone KW - trophic status Y1 - 2013 U6 - https://doi.org/10.1890/ES13-00247.1 SN - 2150-8925 VL - 4 IS - 11 PB - Wiley CY - Washington ER - TY - THES A1 - Zauber, Henrik T1 - A systems biology driven approach for analyzing lipid protein interactions in sterol biosynthesis mutants Y1 - 2013 CY - Potsdam ER - TY - JOUR A1 - Gulbins, Erich A1 - Palmada, Monica A1 - Reichel, Martin A1 - Lueth, Anja A1 - Boehmer, Christoph A1 - Amato, Davide A1 - Mueller, Christian P. A1 - Tischbirek, Carsten H. A1 - Groemer, Teja W. A1 - Tabatabai, Ghazaleh A1 - Becker, Katrin Anne A1 - Tripal, Philipp A1 - Staedtler, Sven A1 - Ackermann, Teresa F. A1 - van Brederode, Johannes A1 - Alzheimer, Christian A1 - Weller, Michael A1 - Lang, Undine E. A1 - Kleuser, Burkhard A1 - Grassme, Heike A1 - Kornhuber, Johannes T1 - Acid sphingomyelinase-ceramide system mediates effects of antidepressant drugs JF - Nature medicine N2 - Major depression is a highly prevalent severe mood disorder that is treated with antidepressants. The molecular targets of antidepressants require definition. We investigated the role of the acid sphingomyelinase (Asm)-ceramide system as a target for antidepressants. Therapeutic concentrations of the antidepressants amitriptyline and fluoxetine reduced Asm activity and ceramide concentrations in the hippocampus, increased neuronal proliferation, maturation and survival and improved behavior in mouse models of stress-induced depression. Genetic Asm deficiency abrogated these effects. Mice overexpressing Asm, heterozygous for acid ceramidase, treated with blockers of ceramide metabolism or directly injected with C16 ceramide in the hippocampus had higher ceramide concentrations and lower rates of neuronal proliferation, maturation and survival compared with controls and showed depression-like behavior even in the absence of stress. The decrease of ceramide abundance achieved by antidepressant-mediated inhibition of Asm normalized these effects. Lowering ceramide abundance may thus be a central goal for the future development of antidepressants. Y1 - 2013 U6 - https://doi.org/10.1038/nm.3214 SN - 1078-8956 VL - 19 IS - 7 SP - 934 EP - + PB - Nature Publ. Group CY - New York ER - TY - JOUR A1 - Fechner, Lennart A1 - Baumann, Otto A1 - Walz, Bernd T1 - Activation of the cyclic AMP pathway promotes serotonin-induced Ca2+ oscillations in salivary glands of the blowfly Calliphora vicina JF - Cell calcium N2 - Ca2+ and cAMP signalling pathways interact in a complex manner at multiple sites. This crosstalk fine-tunes the spatiotemporal patterns of Ca2+ and cAMP signals. In salivary glands of the blowfly Calliphora vicina fluid secretion is stimulated by serotonin (5-hydroxytryptamine, 5-HT) via activation of two different 5-HT receptors coupled to the InsP(3)/Ca2+ (Cv5-HT2 alpha) or the cAMP pathway (Cv5-HT7), respectively. We have shown recently in permeabilized gland cells that cAMP sensitizes InsP(3)-induced Ca2+ release to InsP(3). Here we study the effects of the CAMP signalling pathway on 5-HT-induced oscillations in transepithelial potential (TEP) and in intracellular [Ca2+]. We show: (1) Blocking the activation of the cAMP pathway by cinanserin suppresses the generation of TEP and Ca2+ oscillations, (2) application of 8-CPT-cAMP in the presence of cinanserin restores 5-HT-induced TEP and Ca2+ oscillations, (3) 8-CPT-cAMP sensitizes the InsP(3)/Ca2+ signalling pathway to 5-HT and the Cv5-HT2 alpha, receptor agonist 5-MeOT, (4) 8-CPT-cAMP induces Ca2+ oscillations in cells loaded with subthreshold concentrations of InsP(3), (5) inhibition of protein kinase A by H-89 abolishes 5-HT-induced TEP and Ca2+ spiking and mimics the effect of cinanserin. These results suggest that activation of the cyclic AMP pathway promotes the generation of 5-HT-induced Ca2+ oscillations in blowfly salivary glands. KW - Calcium KW - Ca2+ KW - Calcium oscillations KW - cAMP KW - Signalling KW - Crosstalk KW - Salivary gland KW - Calliphora KW - Blowfly KW - Insect Y1 - 2013 U6 - https://doi.org/10.1016/j.ceca.2012.10.004 SN - 0143-4160 VL - 53 IS - 2 SP - 94 EP - 101 PB - Churchill Livingstone CY - Edinburgh ER - TY - THES A1 - Freudenberger, Lisa T1 - Adaptation of nature conservation to global change: an ecosystem-based approach to priority-setting Y1 - 2013 CY - Potsdam ER - TY - JOUR A1 - Andres, Dorothee A1 - Gohlke, Ulrich A1 - Bröker, Nina Kristin A1 - Schulze, Stefan A1 - Rabsch, Wolfgang A1 - Heinemann, Udo A1 - Barbirz, Stefanie A1 - Seckler, Robert T1 - An essential serotype recognition pocket on phage P22 tailspike protein forces Salmonella enterica serovar Paratyphi A O-antigen fragments to bind as nonsolution conformers JF - Glycobiology N2 - Bacteriophage P22 recognizes O-antigen polysaccharides of Salmonella enterica subsp. enterica (S.) with its tailspike protein (TSP). In the serovars S. Typhimurium, S. Enteritidis, and S. Paratyphi A, the tetrasaccharide repeat units of the respective O-antigens consist of an identical main chain trisaccharide but different 3,6-dideoxyhexose substituents. Here, the epimers abequose, tyvelose and paratose determine the specific serotype. P22 TSP recognizes O-antigen octasaccharides in an extended binding site with a single 3,6-dideoxyhexose binding pocket. We have isolated S. Paratyphi A octasaccharides which were not available previously and determined the crystal structure of their complex with P22 TSP. We discuss our data together with crystal structures of complexes with S. Typhimurium and S. Enteritidis octasaccharides determined earlier. Isothermal titration calorimetry showed that S. Paratyphi A octasaccharide binds P22 TSP less tightly, with a difference in binding free energy of similar to 7 kJ mol(-1) at 20 degrees C compared with S. Typhimurium and S. Enteritidis octasaccharides. Individual protein-carbohydrate contacts were probed by amino acid replacements showing that the dideoxyhexose pocket contributes to binding of all three serotypes. However, S. Paratyphi A octasaccharides bind in a conformation with an energetically unfavorable phi/epsilon glycosidic bond angle combination. In contrast, octasaccharides from the other serotypes bind as solution-like conformers. Two water molecules are conserved in all P22 TSP complexes with octasaccharides of different serotypes. They line the dideoxyhexose binding pocket and force the S. Paratyphi A octasaccharides to bind as nonsolution conformers. This emphasizes the role of solvent as part of carbohydrate binding sites. KW - bacterial O-antigen KW - carbohydrate interaction KW - paratose KW - structural thermodynamics KW - tailspike protein Y1 - 2013 U6 - https://doi.org/10.1093/glycob/cws224 SN - 0959-6658 VL - 23 IS - 4 SP - 486 EP - 494 PB - Oxford Univ. Press CY - Cary ER - TY - JOUR A1 - Nguyen, Hung M. A1 - Schippers, Jos H. M. A1 - Goni-Ramos, Oscar A1 - Christoph, Mathias P. A1 - Dortay, Hakan A1 - van der Hoorn, Renier A. L. A1 - Müller-Röber, Bernd T1 - An upstream regulator of the 26S proteasome modulates organ size in Arabidopsis thaliana JF - The plant journal N2 - In both animal and plant kingdoms, body size is a fundamental but still poorly understood attribute of biological systems. Here we report that the Arabidopsis NAC transcription factor Regulator of Proteasomal Gene Expression' (RPX) controls leaf size by positively modulating proteasome activity. We further show that the cis-element recognized by RPX is evolutionarily conserved between higher plant species. Upon over-expression of RPX, plants exhibit reduced growth, which may be reversed by a low concentration of the pharmacological proteasome inhibitor MG132. These data suggest that the rate of protein turnover during growth is a critical parameter for determining final organ size. KW - Arabidopsis thaliana KW - organ size KW - evolution KW - leaf development KW - proteasome KW - gene regulatory network Y1 - 2013 U6 - https://doi.org/10.1111/tpj.12097 SN - 0960-7412 VL - 74 IS - 1 SP - 25 EP - 36 PB - Wiley-Blackwell CY - Hoboken ER - TY - THES A1 - Bortfeld, Silvia T1 - Analysis of Medicago truncatula transcription factors involved in the arbuscular mycorrhizal symbiosis T1 - Analyse von Medicago truncatula Transkriptionsfaktoren, die während der arbuskulären Mykorrhiz-Symbiose eine Rolle spielen N2 - For the first time the transcriptional reprogramming of distinct root cortex cells during the arbuscular mycorrhizal (AM) symbiosis was investigated by combining Laser Capture Mirodissection and Affymetrix GeneChip® Medicago genome array hybridization. The establishment of cryosections facilitated the isolation of high quality RNA in sufficient amounts from three different cortical cell types. The transcript profiles of arbuscule-containing cells (arb cells), non-arbuscule-containing cells (nac cells) of Rhizophagus irregularis inoculated Medicago truncatula roots and cortex cells of non-inoculated roots (cor) were successfully explored. The data gave new insights in the symbiosis-related cellular reorganization processes and indicated that already nac cells seem to be prepared for the upcoming fungal colonization. The mycorrhizal- and phosphate-dependent transcription of a GRAS TF family member (MtGras8) was detected in arb cells and mycorrhizal roots. MtGRAS shares a high sequence similarity to a GRAS TF suggested to be involved in the fungal colonization processes (MtRAM1). The function of MtGras8 was unraveled upon RNA interference- (RNAi-) mediated gene silencing. An AM symbiosis-dependent expression of a RNAi construct (MtPt4pro::gras8-RNAi) revealed a successful gene silencing of MtGras8 leading to a reduced arbuscule abundance and a higher proportion of deformed arbuscules in root with reduced transcript levels. Accordingly, MtGras8 might control the arbuscule development and life-time. The targeting of MtGras8 by the phosphate-dependent regulated miRNA5204* was discovered previously (Devers et al., 2011). Since miRNA5204* is known to be affected by phosphate, the posttranscriptional regulation might represent a link between phosphate signaling and arbuscule development. In this work, the posttranscriptional regulation was confirmed by mis-expression of miRNA5204* in M. truncatula roots. The miRNA-mediated gene silencing affects the MtGras8 transcript abundance only in the first two weeks of the AM symbiosis and the mis-expression lines seem to mimic the phenotype of MtGras8-RNAi lines. Additionally, MtGRAS8 seems to form heterodimers with NSP2 and RAM1, which are known to be key regulators of the fungal colonization process (Hirsch et al., 2009; Gobbato et al., 2012). These data indicate that MtGras8 and miRNA5204* are linked to the sym pathway and regulate the arbuscule development in phosphate-dependent manner. N2 - Die Leguminose Medicago truncatula (gehört zur Gattung des Schneckenklees) ist in der Lage sowohl eine Symbiose mit stickstofffixierenden Bakterien (Rhizobien), als auch mit Mykorrhiza-Pilzen einzugehen. Der Mykorrhiza-Pilz Rhizophagus irregularis dringt in die Wurzelrindenzellen ein und bildet Strukturen aus, die als Arbuskeln bezeichnet werden. Diese ermöglichen den Transfer von Nährstoffen, wie Phosphat in die Wurzelzellen. Die Pflanze liefert hingegen bis zu 20 % ihrer Photosyntheseprodukte an den Pilz. Da die Lebenszeit der Arbuskeln nur wenige Tage beträgt, können Wurzelrindenzellen mehrere Arbuskeln nacheinander beherbergen. Somit können neben arbuskelhaltigen, auch nicht-arbuskelhaltige Zellen in kolonisierten Wurzeln auftreten. Die nicht-arbuskelhaltigen Zellen beeinträchtigen die Sensitivität von Genregulationsanalysen, wenn die Genregulation während der Mykorrhiza-Symbiose anhand von ganzen kolonisierten Wurzeln untersucht wird. In dieser Arbeit konnte eine Zelltyp-spezifische Analyse der Genregulation von arbuskelhaltigen und nicht-arbuskelhaltigen Zellen durchgeführt, und eine Erhöhung der Sensitivität erreicht werden. Mittels Laser Capture Microdissection wurden Zellen aus Gefrierschnitten von Wurzeln isoliert. Aus den so gewonnen Zellen konnte RNA von ausreichender Qualität und Quantität extrahiert werden, um das Transkriptom der beiden Zelltypen mittels Mikroarrayhybridisierung zu untersuchen. Transkriptionsfaktoren (TFs) spielen wahrscheinlich eine Schlüsselrolle in der Umprogrammierung von Wurzelzellen während der Mykorrhiza-Symbiose. Daher wurde die Genregulation von TF-Genen in den zwei Zelltypen gezielt untersucht. Anhand von quantitativer RT-PCR und Promoter-Reporter-Fusionen wurde die differentielle Expression von mehreren TF-Transkripten in den verschiedenen Zelltypen bestätigt. Die Charakterisierung eines potentiellen GRAS TF (MtGRAS8) konnte eine stark Symbiose- und Phosphat-abhängige Induktion von Transkripten bestätigt werden. Mutanten mit verringerter MtGras8 Transkriptmenge wiesen eine verringerte Arbuskelzahl und deformierte Arbuskeln auf. MtGras8 scheint daher an der Arbuskelentwicklung beteiligt zu sein. Vorherige Experimente zeigten, dass MtGras8 Transkripte, von der Phosphat-regulierten MikroRNA5204* geschnitten werden (Devers et al., 2011). Dies konnte durch Überexpression der MikroRNA5204* in vivo bestätigt werden. Weiterhin konnten Protein-Protein-Interaktionen von MtGras8 mit bekannten GRAS TFs (NSP1, NSP2, RAM1) nachgewiesen und daraus eine Verbindung zu bekannten Symbiose-induzierten Signalkaskaden geschlossen werden. In dieser Arbeit wurde erstmals die Umprogrammierung von nicht-arbuskelhaltigen Zellen untersucht und neue Regulationselemente für die Kontrolle der Arbuskelentwicklung, wie MtGRAS8 und MikroRNA5204*, charakterisiert. KW - arbuskuläre Mykorrhiza-Symbiose KW - Transkriptionsfaktoren KW - Zelltyp-spezifisch KW - Transkriptomanalyse KW - arbuscular mycorrhizal symbiosis KW - transcription factors KW - cell type-specific KW - transcriptome analysis Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-70664 ER - TY - JOUR A1 - Hill, Natascha A1 - Leow, Alexander A1 - Bleidorn, Christoph A1 - Groth, Detlef A1 - Tiedemann, Ralph A1 - Selbig, Joachim A1 - Hartmann, Stefanie T1 - Analysis of phylogenetic signal in protostomial intron patterns using Mutual Information JF - Theory in biosciences N2 - Many deep evolutionary divergences still remain unresolved, such as those among major taxa of the Lophotrochozoa. As alternative phylogenetic markers, the intron-exon structure of eukaryotic genomes and the patterns of absence and presence of spliceosomal introns appear to be promising. However, given the potential homoplasy of intron presence, the phylogenetic analysis of this data using standard evolutionary approaches has remained a challenge. Here, we used Mutual Information (MI) to estimate the phylogeny of Protostomia using gene structure data, and we compared these results with those obtained with Dollo Parsimony. Using full genome sequences from nine Metazoa, we identified 447 groups of orthologous sequences with 21,732 introns in 4,870 unique intron positions. We determined the shared absence and presence of introns in the corresponding sequence alignments and have made this data available in "IntronBase", a web-accessible and downloadable SQLite database. Our results obtained using Dollo Parsimony are obviously misled through systematic errors that arise from multiple intron loss events, but extensive filtering of data improved the quality of the estimated phylogenies. Mutual Information, in contrast, performs better with larger datasets, but at the same time it requires a complete data set, which is difficult to obtain for orthologs from a large number of taxa. Nevertheless, Mutual Information-based distances proved to be useful in analyzing this kind of data, also because the estimation of MI-based distances is independent of evolutionary models and therefore no pre-definitions of ancestral and derived character states are necessary. KW - Mutual Information KW - Evolution KW - Gene structure Y1 - 2013 U6 - https://doi.org/10.1007/s12064-012-0173-0 SN - 1431-7613 VL - 132 IS - 2 SP - 93 EP - 104 PB - Springer CY - New York ER - TY - JOUR A1 - Basel, Nicolai A1 - Harms, Ute A1 - Prechtl, Helmut T1 - Analysis of students' arguments on evolutionary theory JF - Journal of biological education N2 - A qualitative exploratory study was conducted to reveal students' argumentation skills in the context of the topic of evolution. Transcripts from problem-centred interviews on secondary students' beliefs about evolutionary processes of adaptation were analysed using a content analysis approach. For this purpose two categorical systems were deductively developed: one addressing the complexity of students' arguments, the other focusing on students' use of argumentation schemes. Subsequently, the categorical systems were inductively elaborated upon the basis of the analysed material showing a satisfactory inter-rater reliability. Regarding the arguments' complexity, students produced mainly single claims or claims with a single justification consisting of either data or warrants. With regard to argumentation schemes students drew their arguments mainly using causal schemes, analogies, or illustrative examples. Results are discussed in light of possible implications for teaching evolutionary theory using classroom argumentation. KW - evolutionary theory KW - reasoning KW - argumentation KW - argumentation schemes Y1 - 2013 U6 - https://doi.org/10.1080/00219266.2013.799078 SN - 0021-9266 SN - 2157-6009 VL - 47 IS - 4 SP - 192 EP - 199 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - JOUR A1 - Badalyan, Artavazd A1 - Yoga, Etienne Galemou A1 - Schwuchow, Viola A1 - Pöller, Sascha A1 - Schuhmann, Wolfgang A1 - Leimkühler, Silke A1 - Wollenberger, Ursula T1 - Analysis of the interaction of the molybdenum hydroxylase PaoABC from Escherichia coli with positively and negatively charged metal complexes JF - Electrochemistry communications : an international journal dedicated to rapid publications in electrochemistry N2 - An unusual behavior of the periplasmic aldehyde oxidoreductase (PaoABC) from Escherichia coil has been observed from electrochemical investigations of the enzyme catalyzed oxidation of aromatic aldehydes with different mediators under different conditions of ionic strength. The enzyme has similarity to other molybdoenzymes of the xanthine oxidase family, but the catalytic behavior turned out to be very different. Under steady state conditions the turnover of PaoABC is maximal at pH 4 for the negatively charged ferricyanide and at pH 9 for a positively charged osmium complex. Stopped-flow kinetic measurements of the catalytic half reaction showed that oxidation of benzaldehyde proceeds also above pH 7. Thus, benzaldehyde oxidation can proceed under acidic and basic conditions using this enzyme, a property which has not been described before for molybdenum hydroxylases. It is also suggested that the electron transfer with artificial electron acceptors and PaoABC can proceed at different protein sites and depends on the nature of the electron acceptor in addition to the ionic strength. (C) 2013 Elsevier B.V. All rights reserved. KW - Electron transfer KW - Multi-cofactor enzymes KW - Molybdoenzymes KW - Aldehyde oxidoreductase Y1 - 2013 U6 - https://doi.org/10.1016/j.elecom.2013.09.017 SN - 1388-2481 SN - 1873-1902 VL - 37 SP - 5 EP - 7 PB - Elsevier CY - New York ER - TY - JOUR A1 - Liang, Wei A1 - Heinrich, Ingo A1 - Helle, Gerhard A1 - Linan, Isabel Dorado A1 - Heinken, Thilo T1 - Applying CLSM to increment core surfaces for histometric analyses a novel advance in quantitative wood anatomy JF - Dendrochronologia : an interdisciplinary journal of tree-ring science N2 - A novel procedure has been developed to conduct cell structure measurements on increment core samples of conifers. The procedure combines readily available hardware and software equipment. The essential part of the procedure is the application of a confocal laser scanning microscope (CLSM) which captures images directly from increment cores surfaced with the advanced WSL core-microtome. Cell wall and lumen are displayed with a strong contrast due to the monochrome black and green nature of the images. Consecutive images are merged into long images representing entire increment cores which are then analysed for cell structures in suitable software. KW - Wood anatomy KW - Cell structures KW - Confocal laser scanning microscopy KW - CLSM KW - Dendrochronology KW - Surface preparation Y1 - 2013 U6 - https://doi.org/10.1016/j.dendro.2012.09.002 SN - 1125-7865 VL - 31 IS - 2 SP - 140 EP - 145 PB - Elsevier CY - Jena ER - TY - THES A1 - Döring, Anett T1 - Arabidopsis thaliana endomembrane / Golgi V-ATPase activity regulates the cellulose synthase life-time at, and the delivery to, the plasma membrane Y1 - 2013 CY - Potsdam ER - TY - JOUR A1 - Schrade, Lisa A1 - Scheffler, Christiane T1 - Assessing the applicability of the digital laser rangefinder GLM Professional (R) Bosch 250 VF for anthropometric field studies JF - Journal of biological and clinical anthropology : Anthropologischer Anzeiger ; Mitteilungsorgan der Gesellschaft für Anthropologie N2 - The digital laser rangefinder GLM Professional (R) BOSCH 250 VF was tested as a modified preproduction model with regard to its applicability of quantifying humans' height. The aim of this investigation was to determine and evaluate the instrument's precision, as well as its manageability within anthropometric field studies. Data collected by the digital laser rangefinder did not show a significant difference to data of control by an anthropometer. Furthermore, more than 96% of the difference values are located within area of agreement. Nevertheless, the GLM Professional (R) is a highly sensitive instrument and mean SD within threefold data acquisition is twice as high as SD resulting from data collection by an anthropometer. However, due to the minimal percentage differences within data acquisition and compared to the standard method, the GLM Professional (R) is proved to be a reliable instrument and to be highly applicable for anthropometric field studies. Furthermore, due to its excellent manageability and compact size, the GLM Professional (R) shows a very good applicability even for less trained anthropometrists and thus ameliorates the possibilities of collecting reliable data within anthropometric field studies. KW - anthropometric field studies KW - height KW - measuring instrument KW - digital laser range finder Y1 - 2013 U6 - https://doi.org/10.1127/0003-5548/2013/0223 SN - 0003-5548 VL - 70 IS - 2 SP - 137 EP - 145 PB - Schweizerbart CY - Stuttgart ER - TY - JOUR A1 - Schrade, Lisa A1 - Scheffler, Christiane T1 - Assessing the applicability of the digital laser rangefinder GLM Professional Bosch 250 VF for anthropometric field studies Y1 - 2013 ER - TY - JOUR A1 - Eigemann, Falk A1 - Hilt, Sabine A1 - Salka, Ivette A1 - Grossart, Hans-Peter T1 - Bacterial community composition associated with freshwater algae species specificity vs. dependency on environmental conditions and source community JF - FEMS microbiology ecology N2 - We studied bacterial associations with the green alga Desmodesmus armatus and the diatom Stephanodiscus minutulus under changing environmental conditions and bacterial source communities, to evaluate whether bacteriaalgae associations are species-specific or more generalized and determined by external factors. Axenic and xenic algae were incubated in situ with and without allelopathically active macrophytes, and in the laboratory with sterile and nonsterile lake water and an allelochemical, tannic acid (TA). Bacterial community composition (BCC) of algae-associated bacteria was analyzed by denaturing gradient gel electrophoresis (DGGE), nonmetric multidimensional scaling, cluster analyses, and sequencing of DGGE bands. BCC of xenic algal cultures of both species were not significantly affected by changes in their environment or bacterial source community, except in the case of TA additions. Species-specific interactions therefore appear to overrule the effects of environmental conditions and source communities. The BCC of xenic and axenic D.armatus cultures subjected to in situ bacterial colonization, however, had lower similarities (ca.55%), indicating that bacterial precolonization is a strong factor for bacteriaalgae associations irrespective of environmental conditions and source community. Our findings emphasize the ecological importance of species-specific bacteriaalgae associations with important repercussions for other processes, such as the remineralization of nutrients, and organic matter dynamics. KW - allelopathy KW - bacteriaalgae associations KW - heterotrophic bacteria KW - species-specific Y1 - 2013 U6 - https://doi.org/10.1111/1574-6941.12022 SN - 0168-6496 VL - 83 IS - 3 SP - 650 EP - 663 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Radchuk, Viktoriia A1 - Johst, Karin A1 - Gröneveld, Juergen A1 - Grimm, Volker A1 - Schtickzelle, Nicolas T1 - Behind the scenes of population viability modeling predicting butterfly metapopulation dynamics under climate change JF - Ecological modelling : international journal on ecological modelling and engineering and systems ecolog N2 - Studies explaining the choice of model structure for population viability analysis (PVA) are rare and no such study exists for butterfly species, a focal group for conservation. Here, we describe in detail the development of a model to predict population viability of a glacial relict butterfly species, Boloria eunomia, under climate change. We compared four alternative formulations of an individual-based model, differing in the environmental factors acting on the survival of immature life stages: temperature (only temperature impact), weather (temperature, precipitation, and sunshine), temperature and parasitism, and weather and parasitism. Following pattern-oriented modeling, four observed patterns were used to contrast these models: one qualitative (response of population size to habitat parameters) and three quantitative ones describing population dynamics during eight years (mean and variability of population size, and magnitude of the temporal autocorrelation in yearly population growth rates). The four model formulations were not equally able to depict population dynamics under current environmental conditions; the model including only temperature was selected as the most parsimonious model sufficiently well reproducing the empirical patterns. We used all four model formulations to test a range of climate change scenarios that were characterized by changes in both mean and variability of the weather variables. All models predicted adverse effects of climate change and resulted in the same ranking of mean climate change scenarios. However, models differed in their absolute values of population viability measures, underlining the need to explicitly choose the most appropriate model formulation and avoid arbitrary usage of environmental drivers in a model. We conclude that further applications of pattern-oriented modeling to butterfly and other species are likely to help in identifying the key factors impacting the viability of certain taxa, which, ultimately, will aid and speed up informed management decisions for endangered species under climate change. KW - Individual-based model KW - Population viability analysis KW - Glacial relict species KW - Life cycle KW - Boloria eunomia KW - Pattern-oriented modeling KW - Model structure Y1 - 2013 U6 - https://doi.org/10.1016/j.ecolmodel.2013.03.014 SN - 0304-3800 VL - 259 IS - 2 SP - 62 EP - 73 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Seifan, Merav A1 - Seifan, Tal A1 - Schiffers, Katja A1 - Jeltsch, Florian A1 - Tielboerger, Katja T1 - Beyond the competition-colonization trade-off - linking multiple trait response to disturbance characteristics JF - The American naturalist : a bi-monthly journal devoted to the advancement and correlation of the biological sciences N2 - Disturbances' role in shaping communities is well documented but highly disputed. We suggest replacing the overused two-trait trade-off approach with a functional group scheme, constructed from combinations of four key traits that represent four classes of species' responses to disturbances. Using model results and field observations from sites affected by two highly different disturbances, we demonstrated that popular dichotomous trade-offs are not sufficient to explain community dynamics, even if some emerge under certain conditions. Without disturbances, competition was only sufficient to predict species survival but not relative success, which required some escape mechanism (e.g., long-term dormancy). With highly predictable and large-scale disturbances, successful species showed a combination of high individual tolerance to disturbance and, more surprisingly, high competitive ability. When disturbances were less predictable, high individual tolerance and long-term seed dormancy were favored, due to higher environmental uncertainty. Our study demonstrates that theories relying on a small number of predefined trade-offs among traits (e.g., competition-colonization trade-off) may lead to unrealistic results. We suggest that the understanding of disturbance-community relationships can be significantly improved by employing sets of relevant trait assemblies instead of the currently common approach in which trade-offs are assumed in advance. KW - competition resistance trade-off KW - functional types KW - intermediate disturbance hypothesis KW - plant communities KW - species assemblies Y1 - 2013 U6 - https://doi.org/10.1086/668844 SN - 0003-0147 VL - 181 IS - 2 SP - 151 EP - 160 PB - Univ. of Chicago Press CY - Chicago ER - TY - JOUR A1 - Carregari, Victor Corasolla A1 - Floriano, Rafael Stuani A1 - Rodrigues-Simioni, Lea A1 - Winck, Flavia V. A1 - Baldasso, Paulo Aparecido A1 - Ponce-Soto, Luis Alberto A1 - Marangoni, Sergio T1 - Biochemical, Pharmacological, and Structural Characterization of New Basic PLA(2) Bbil-TX from Bothriopsis bilineata Snake Venom JF - BioMed research international N2 - Bbil-TX, a PLA(2), was purified from Bothriopsis bilineata snake venom after only one chromatographic step using RP-HPLC on mu-Bondapak C-18 column. A molecular mass of 14243.8 Da was confirmed by -Tof ltima API ESI/ MS (TOF MS mode) mass spectrometry. The partial protein sequence obtained was then submitted to BLASTp, with the search restricted to PLA(2) from snakes and shows high identity values when compared to other PLA(2)s. PLA(2) activity was presented in the presence of a synthetic substrate and showed a minimum sigmoidal behavior, reaching its maximal activity at pH 8.0 and 25-37 degrees C. Maximum PLA(2) activity required Ca2+ and in the presence of Cd2+, Zn2+, Mn2+, and Mg2+ it was reduced in the presence or absence of Ca2+. Crotapotin from Crotalus durissus cascavella rattlesnake venom and antihemorrhagic factor DA2-II from Didelphis albiventris opossum sera under optimal conditions significantly inhibit the enzymatic activity. Bbil-TX induces myonecrosis in mice. The fraction does not show a significant cytotoxic activity in myotubes and myoblasts (C2C12). The infiammatory events induced in the serum of mice by Bbil-TX isolated from Bothriopsis bilineata snake venom were investigated. An increase in vascular permeability and in the levels of TNF-a, IL-6, and IL-1 was was induced. Since Bbil-TX exerts a stronger proinfiammatory effect, the phospholipid hydrolysis may be relevant for these phenomena. Y1 - 2013 U6 - https://doi.org/10.1155/2013/612649 SN - 2314-6133 SN - 2314-6141 PB - Hindawi Publishing Corp. CY - New York ER - TY - THES A1 - Sandmann, Michael T1 - Biochemische und cytologische Marker der Zellentwicklung synchronisierter Stämme con Chlamydomonas reinhardtii Y1 - 2013 CY - Potsdam ER - TY - THES A1 - Badalyan, Artavazd T1 - Bioelectrochemistry of molybdenum hydroxylases : aldehyde oxidoreductase PaoABC from escherichia coli and xanthine dehydrogenase from rhodobacter capsulatus Y1 - 2013 CY - Potsdam ER - TY - JOUR A1 - Scheffler, Christiane ED - Hermanussen, Michael T1 - Biological age JF - Auxology : Studying Human Growth and Development Y1 - 2013 SN - 978-3-510-65278-5 SP - 44 EP - 47 PB - Schweizerbart Science Publishers CY - Stuttgart ER - TY - INPR A1 - Cierjacks, Arne A1 - Kowarik, Ingo A1 - Joshi, Jasmin Radha A1 - Hempel, Stefan A1 - Ristow, Michael A1 - von der Lippe, Moritz A1 - Weber, Ewald T1 - Biological flora of the british isles: robinia pseudoacacia T2 - The journal of ecology N2 - This account presents information on all aspects of the biology of Robinia pseudoacacia L. that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, and history and conservation.Robinia pseudoacacia, false acacia or black locust, is a deciduous, broad-leaved tree native to North America. The medium-sized, fast-growing tree is armed with spines, and extensively suckering. It has become naturalized in grassland, semi-natural woodlands and urban habitats. The tree is common in the south of the British Isles and in many other regions of Europe.Robinia pseudoacacia is a light-demanding pioneer species, which occurs primarily in disturbed sites on fertile to poor soils. The tree does not tolerate wet or compacted soils. In contrast to its native range, where it rapidly colonizes forest gaps and is replaced after 15-30years by more competitive tree species, populations in the secondary range can persist for a longer time, probably due to release from natural enemies.Robinia pseudoacacia reproduces sexually, and asexually by underground runners. Disturbance favours clonal growth and leads to an increase in the number of ramets. Mechanical stem damage and fires also lead to increased clonal recruitment. The tree benefits from di-nitrogen fixation associated with symbiotic rhizobia in root nodules. Estimated symbiotic nitrogen fixation rates range widely from 23 to 300kgha(-1)year(-1). The nitrogen becomes available to other plants mainly by the rapid decay of nitrogen-rich leaves.Robinia pseudoacacia is host to a wide range of fungi both in the native and introduced ranges. Megaherbivores are of minor significance in Europe but browsing by ungulates occurs in the native range. Among insects, the North American black locust gall midge (Obolodiplosis robiniae) is specific to Robinia and is spreading rapidly throughout Europe. In parts of Europe, Robinia pseudoacacia is considered an invasive non-indigenous plant and the tree is controlled. Negative impacts include shading and changes of soil conditions as a result of nitrogen fixation. KW - climatic limitation KW - ecophysiology KW - geographical and altitudinal distribution KW - germination KW - invasive KW - mycorrhiza KW - nitrogen fixation KW - parasites and diseases KW - reproductive biology KW - soils Y1 - 2013 U6 - https://doi.org/10.1111/1365-2745.12162 SN - 0022-0477 SN - 1365-2745 VL - 101 IS - 6 SP - 1623 EP - 1640 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Hechavarria, Julio C. A1 - Macias, Silvio A1 - Vater, Marianne A1 - Voss, Cornelia A1 - Mora, Emanuel C. A1 - Kossl, Manfred T1 - Blurry topography for precise target-distance computations in the auditory cortex of echolocating bats JF - Nature Communications N2 - Echolocating bats use the time from biosonar pulse emission to the arrival of echo (defined as echo delay) to calculate the space depth of targets. In the dorsal auditory cortex of several species, neurons that encode increasing echo delays are organized rostrocaudally in a topographic arrangement defined as chronotopy. Precise chronotopy could be important for precise target-distance computations. Here we show that in the cortex of three echolocating bat species (Pteronotus quadridens, Pteronotus parnellii and Carollia perspicillata), chronotopy is not precise but blurry. In all three species, neurons throughout the chronotopic map are driven by short echo delays that indicate the presence of close targets and the robustness of map organization depends on the parameter of the receptive field used to characterize neuronal tuning. The timing of cortical responses (latency and duration) provides a binding code that could be important for assembling acoustic scenes using echo delay information from objects with different space depths. Y1 - 2013 U6 - https://doi.org/10.1038/ncomms3587 SN - 2041-1723 VL - 4 IS - 10 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Scheffler, Christiane ED - Hermanussen, Michael T1 - Body composition JF - Auxology : Studying Human Growth and Development Y1 - 2013 SN - 978-3-510-65278-5 SP - 30 EP - 31 PB - Schweizerbart Science Publishers CY - Stuttgart ER - TY - THES A1 - Rietsch, Katrin T1 - Body composition especially external skeletal robustness in association with physical activity and recreation in pre-pubertal children : a national and international investigation T1 - Körperzusammensetzung insbesondere die äußere Skelettrobustizität im Zusammenhang mit der körperlichen Aktivität und der Freizeit in präpubertären Kindern : eine nationale und internationale Untersuchung N2 - In children the way of life, nutrition and recreation changed in recent years and as a consequence body composition shifted as well. It is established that overweight belongs to a global problem. In addition, German children exhibit a less robust skeleton than ten years ago. These developments may elevate the risk of cardiovascular diseases and skeletal modifications. Heredity and environmental factors as nutrition, socioeconomic status, physical activity and inactivity influence fat accumulation and the skeletal system. Based on these negative developments associations between type of body shape, skeletal measures and physical activity; relations between external skeletal robustness, physical activity and inactivity, BMI and body fat and also the progress of body composition especially external skeletal robustness in comparison in Russian and German children were investigated. In a cross-sectional study 691 German boys and girls aged 6 to 10 years were examined. Anthropometric measurements were taken and questionnaires about physical activity and inactivity were answered by parents. Additionally, pedometers were worn to determinate the physical activity in children. To compare the body composition in Russian and German children data from the years 2000 and 2010 were used. The study has shown that pyknomorphic individuals exhibit the highest external skeletal robustness and leptomorphic ones the lowest. Leptomorphic children may have a higher risk for bone diseases in adulthood. Pyknomorphic boys are more physically active by tendency. This is assessed as positive because pyknomorphic types display the highest BMI and body fat. Results showed that physical activity may reduce BMI and body fat. In contrast physical inactivity may lead to an increase of BMI and body fat and may rise with increasing age. Physical activity encourages additionally a robust skeleton. Furthermore external skeletal robustness is associated with BMI in order that BMI as a measure of overweight should be consider critically. The international 10-year comparison has shown an increase of BMI in Russian children and German boys. Currently, Russian children exhibit a higher external skeletal robustness than the Germans. However, in Russian boys skeleton is less robust than ten years ago. This trend should be observed in the future as well in other countries. All in all, several measures should be used to describe health situation in children and adults. Furthermore, in children it is essential to support physical activity in order to reduce the risk of obesity and to maintain a robust skeleton. In this way diseases are able to prevent in adulthood. N2 - Die Lebens- und Ernährungsweise sowie die Freizeitaktivitäten von Kindern haben sich im Laufe der letzten Jahre verändert. Daraus resultieren Veränderungen der Körperzusammensetzung. Es ist hinreichend bekannt, dass Übergewicht ein globales Problem ist. Des Weiteren weisen deutsche Kinder ein weniger robustes Skelett auf als noch vor 10 Jahren. Diese Entwicklungen können zu unterschiedlichen Erkrankungen des Herz-Kreislauf-Systems bzw. des Skelettsystems führen. Neben genetischen Faktoren haben Umweltfaktoren wie Ernährung, sozialer Status, die körperliche Aktivität bzw. Inaktivität einen Einfluss auf die Fettakkumulation und das Skelettsystem. Aufgrund der negativen Entwicklungen wurden daher die Zusammenhänge zwischen dem Körperbautyp, Skelettmaßen und der körperlichen Aktivität; die Beziehungen zwischen der äußeren Skelettrobustizität, der körperlichen Aktivität bzw. Inaktivität, dem BMI und dem Körperfettanteil sowie die Entwicklung der Körperzusammensetzung insbesondere die äußere Skelettrobustizität von russischen Kindern im Vergleich zu deutschen Kindern überprüft. In einer Querschnittstudie wurden 691 Jungen und Mädchen im Alter von 6 bis 10 Jahren aus Berlin und Brandenburg untersucht. Es wurden anthropometrische Messungen vorgenommen, Fragebögen bezüglich der sportlichen Aktivität und Inaktivität beantwortet sowie ein Schrittzähler zur Bestimmung der körperlichen Aktivität von den Kindern getragen. Für den internationalen Vergleich der Körperzusammensetzung wurden Daten aus den Jahren 2000 und 2010 von deutschen und russischen Kindern verwendet. Es konnte gezeigt werden, dass der pyknomorphe Körperbautyp die höchste und der leptomorphe Typ die niedrigste äußere Skelettrobustizität aufweisen. Leptomorphe Kinder könnten daher das höchste Risiko für Knochenerkrankungen im Erwachsenenalter aufweisen. Tendenziell zeigen pyknomorphe Jungen eine höhere körperliche Aktivität als die anderen Typen. Dies ist positiv zu bewerten, da die pyknomorphen Typen den höchsten BMI und Körperfettanteil besitzen. Wie die Resultate ergeben, kann die körperliche Aktivität zur Reduktion bzw. Inaktivität zur Erhöhung des BMIs und des Körperfettanteils führen. Die körperliche Inaktivität steigt mit zunehmendem Alter. Die körperliche Aktivität unterstützt weiterhin den Aufbau eines robusten Skeletts. Die äußere Skelettrobustizität ist ebenfalls positiv mit dem BMI assoziiert, so dass dargelegt werden konnte, dass der BMI als Maß für Übergewicht kritisch betrachtet werden sollte. Im internationalen 10-Jahresvergleich zeigt sich eine Zunahme des BMIs bei russischen Kindern und deutschen Jungen. Zurzeit weisen die russischen Kinder immer noch ein robusteres Skelett auf als die Deutschen jedoch ist das Skelett bei russischen Jungen weniger robust als noch vor 10 Jahren. Diese negative Entwicklung sollte weiterhin beobachtet werden auch in anderen Ländern. Alles in allem, sollten immer mehrere Maße zur Beschreibung des Gesundheitszustandes herangezogen werden. Weiterhin ist einer Förderung der körperlichen Aktivität bei Kindern notwendig, um zum einen das Risiko für Übergewicht zu minimieren und zum anderen ein robustes Skelett aufzubauen, um somit Erkrankungen im Erwachsenenalter vorzubeugen. KW - Skelettrobustizität KW - körperliche Bewegung KW - Körperbautyp KW - BMI KW - Körperfett KW - Skeletal robustness KW - physical activity KW - somatotype KW - BMI KW - percentage of body fat Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-66913 ER - TY - THES A1 - Brothers, Soren M. T1 - Carbon gains, losses, and feedbacks in shallow, eutrophic lakes of phytoplankton and macrophyte dominance T1 - Kohlenstoff-Gewinne, Verluste und Rückkopplungen in flachen, nährstoffreichen Seen mit Dominanz von Phytoplankton und Makrophyten N2 - Lakes are increasingly being recognized as an important component of the global carbon cycle, yet anthropogenic activities that alter their community structure may change the way they transport and process carbon. This research focuses on the relationship between carbon cycling and community structure of primary producers in small, shallow lakes, which are the most abundant lake type in the world, and furthermore subject to intense terrestrial-aquatic coupling due to their high perimeter:area ratio. Shifts between macrophyte and phytoplankton dominance are widespread and common in shallow lakes, with potentially large consequences to regional carbon cycling. I thus compared a lake with clear-water conditions and a submerged macrophyte community to a turbid, phytoplankton-dominated lake, describing differences in the availability, processing, and export of organic and inorganic carbon. I furthermore examined the effects of increasing terrestrial carbon inputs on internal carbon cycling processes. Pelagic diel (24-hour) oxygen curves and independent fluorometric approaches of individual primary producers together indicated that the presence of a submerged macrophyte community facilitated higher annual rates of gross primary production than could be supported in a phytoplankton-dominated lake at similar nutrient concentrations. A simple model constructed from the empirical data suggested that this difference between regime types could be common in moderately eutrophic lakes with mean depths under three to four meters, where benthic primary production is a potentially major contributor to the whole-lake primary production. It thus appears likely that a regime shift from macrophyte to phytoplankton dominance in shallow lakes would typically decrease the quantity of autochthonous organic carbon available to lake food webs. Sediment core analyses indicated that a regime shift from macrophyte to phytoplankton dominance was associated with a four-fold increase in carbon burial rates, signalling a major change in lake carbon cycling dynamics. Carbon mass balances suggested that increasing carbon burial rates were not due to an increase in primary production or allochthonous loading, but instead were due to a higher carbon burial efficiency (carbon burial / carbon deposition). This, in turn, was associated with diminished benthic mineralization rates and an increase in calcite precipitation, together resulting in lower surface carbon dioxide emissions. Finally, a period of unusually high precipitation led to rising water levels, resulting in a feedback loop linking increasing concentrations of dissolved organic carbon (DOC) to severely anoxic conditions in the phytoplankton-dominated system. High water levels and DOC concentrations diminished benthic primary production (via shading) and boosted pelagic respiration rates, diminishing the hypolimnetic oxygen supply. The resulting anoxia created redox conditions which led to a major release of nutrients, DOC, and iron from the sediments. This further transformed the lake metabolism, providing a prolonged summertime anoxia below a water depth of 1 m, and leading to the near-complete loss of fish and macroinvertebrates. Pelagic pH levels also decreased significantly, increasing surface carbon dioxide emissions by an order of magnitude compared to previous years. Altogether, this thesis adds an important body of knowledge to our understanding of the significance of the benthic zone to carbon cycling in shallow lakes. The contribution of the benthic zone towards whole-lake primary production was quantified, and was identified as an important but vulnerable site for primary production. Benthic mineralization rates were furthermore found to influence carbon burial and surface emission rates, and benthic primary productivity played an important role in determining hypolimnetic oxygen availability, thus controlling the internal sediment loading of nutrients and carbon. This thesis also uniquely demonstrates that the ecological community structure (i.e. stable regime) of a eutrophic, shallow lake can significantly influence carbon availability and processing. By changing carbon cycling pathways, regime shifts in shallow lakes may significantly alter the role of these ecosystems with respect to the global carbon cycle. N2 - Seen werden zunehmend als wichtige Komponente im globalen Kohlenstoffkreislauf anerkannt. Natürliche Veränderungen und anthropogene Aktivitäten beeinflussen die Struktur der Artengemeinschaft von Seen, was Auswirkungen auf den Transport und Umsatz von Kohlenstoff hat. Diese Arbeit konzentriert sich auf die Beziehung zwischen Kohlenstoffkreislauf und der Gemeinschaftsstruktur der Primärproduzenten in kleinen Flachseen. Diese sind der weltweit häufigste Seentyp und weisen durch ihren im Vergleich zur Fläche großen Umfang eine intensive aquatisch-terrestrische Kopplung auf. In Flachseen treten oft Regimewechsel zwischen Makrophyten- und Phytoplankton-Dominanz auf. Diese können potenziell große Konsequenzen für den regionalen Kohlenstoffkreislauf haben. In dieser Dissertation vergleiche ich einen Klarwassersee mit submersen Makrophyten und einen trüben, Phytoplankton-dominierten See hinsichtlich Verfügbarkeit, Umsatz und Export von organischem und anorganischem Kohlenstoff. Des Weiteren habe ich den Effekt der erhöhten Zufuhr von terrestrischem Kohlenstoff auf den internen Kohlenstoffumsatz untersucht. Sowohl die Tagesgänge der pelagischen Sauerstoff-Konzentrationen als auch Fluoreszenz-basierte Messungen der Primärproduktion bewiesen, dass die Präsenz von submersen Makrophyten eine höhere jährliche Brutto-Primärproduktion im Vergleich zu einem Phytoplankton-dominierten See mit ähnlichen Nährstoffkonzentrationen ermöglicht. Ein einfaches, auf den empirischen Daten basierendes Model zeigt, dass diese Unterschiede in der Brutto-Primärproduktion typisch sind für moderat eutrophe Seen mit einer mittleren Tiefe von unter 3 bis vier Metern. In diesen Seen leistet die benthische Primärproduktion den Hauptbeitrag zur Primärproduktion des ganzen Sees. Daraus wird ersichtlich, dass Regimewechsel von Makrophyten- zur Phytoplankton-Dominanz in Flachseen die Verfügbarkeit von autochthonem organischem Kohlenstoff für das Nahrungsnetz reduzieren. Paläolimnologische Analysen in Sedimentkernen beider Seen wiesen darauf hin, dass der Verlust der Makrophyten mit einer vierfachen Zunahme der Kohlenstoff-Speicherraten einhergeht, und somit zu einer großen Veränderung der Dynamik des Kohlenstoffkreislaufs im See führt. Unsere Kohlenstoff-Massenbilanzen zeigen, dass die Erhöhung der Kohlenstoff-Speicherung im Sediment nicht durch die Erhöhung der Primärproduktion oder durch externe Quellen, sondern durch erhöhte der Effizienz der Speicherung begründet war. Dies geht mit einer reduzierten benthischen Mineralisierungsrate und einer erhöhten Calcitfällung einher und führt zu reduzierten Kohlendioxid-Emissionen. Eine Periode ungewöhnlich hoher Niederschläge mit erhöhten Wasserständen führte im Phytoplankton-dominierten See zu zu einem starken Anstieg der Konzentrationen an gelöstem organischem Kohlenstoff (DOC) und zu anoxischen Bedingungen. Es wurde postuliert, dass zwischen diesen Prozessen eine positive Rückkopplung besteht. Die hohen Wasserstände und DOC-Konzentrationen reduzierten die Lichtversorgung und damit die Primärproduktion im Benthal und erhöhten die pelagischen Respirationsraten. Dadurch verringerte sich die Sauerstoffverfügbarkeit im Hypolimnion. Die dadurch erzeugten Redox-Verhältnisse führten zu einer Freisetzung großer Mengen an Nährstoffen, DOC und Eisen aus dem Sediment. Die während des gesamten Sommers andauernden anoxischen Verhältnisse in Wassertiefen unter 1 m führten zu einem fast vollständigen Verlust von Fischen und Makroinvertebraten. Zusätzlich wurde der pH-Wert im Pelagial signifikant erniedrigt und die Kohlenstoffdioxid-Emissionen im Vergleich zu früheren Jahren verzehnfacht. Insgesamt trägt diese Dissertation wesentliche Aspekte zum besseren Verständnis der Bedeutung des Benthals für den Kohlenstoffkreislauf in Flachseen bei. Der Anteil der benthischen Zone an der Primärproduktion in kleinen Flachseen wurde in Relation zur Gesamtproduktion des Systems quantifiziert. Letztlich zeigt diese Arbeit, dass die Gemeinschaftsstruktur der Primärproduzenten eines eutrophen Flachsees die Verfügbarkeit und den Umsatz von Kohlenstoff signifikant beeinflusst. Regimewechsel in Flachseen können durch Änderungen im internen Kohlenstoffkreislauf deren Rolle im globalen Kohlenstoffkreislauf verändern. KW - Carbon Cycling KW - Primärproduktion KW - Anoxie KW - Brownification KW - Carbon cycling KW - primary production KW - anoxia KW - brownification Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-68200 ER - TY - JOUR A1 - Malinova, Irina A1 - Steup, Martin A1 - Fettke, Jörg T1 - Carbon transitions from either Calvin cycle or transitory starch to heteroglycans as revealed by 14-C-labeling experiments using protoplasts from Arabidopsis JF - Physiologia plantarum N2 - Plants metabolize transitory starch by precisely coordinated plastidial and cytosolic processes. The latter appear to include the action of water-soluble heteroglycans (SHG(in)) whose monosaccharide pattern is similar to that of apoplastic glycans (SHG(ex)) but, unlike SHG(ex), SHG(in) strongly interacts with glucosyl transferases. In this study, we analyzed starch metabolism using mesophyll protoplasts from wild-type plants and two knock-out mutants [deficient in the cytosolic transglucosidase, disproportionating isoenzyme 2 (DPE2) or the plastidial phosphoglucomutase (PGM1)] from Arabidopsis thaliana. Protoplasts prelabeled by photosynthetic (CO2)-C-14 fixation were transferred to an unlabeled medium and were darkened or illuminated. Carbon transitions from the Calvin cycle or from starch to both SHG(in) and SHG(ex) were analyzed. In illuminated protoplasts, starch turn-over was undetectable but darkened protoplasts continuously degraded starch. During illumination, neither the total C-14 content nor the labeling patterns of the sugar residues of SHG(in) were significantly altered but both the total amount and the labeling of the constituents of SHG(ex) increased with time. In darkened protoplasts, the C-14-content of most of the sugar residues of SHG(in) transiently and strongly increased and then declined. This effect was not observed in any SHG(ex) constituent. In darkened DPE2-deficient protoplasts, none of the SHG(in) constituents exhibited an essential transient increase in labeling. In contrast, some residues of SHG(in) from the PGM1 mutant exhibited a transient increase in label but this effect significantly differed from that of the wild type. Two conclusions are reached: first, SHG(in) and SHG(ex) exert different metabolic functions and second, SHG(in) is directly involved in starch degradation. Y1 - 2013 U6 - https://doi.org/10.1111/ppl.12033 SN - 0031-9317 VL - 149 IS - 1 SP - 25 EP - 44 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Wang, Jing A1 - Fritzsch, Claire A1 - Bernarding, Johannes A1 - Krause, Thomas A1 - Mauritz, Karl-Heinz A1 - Brunetti, Maddalena A1 - Dohle, Christian T1 - Cerebral activation evoked by the mirror illusion of the hand in stroke patients compared to normal subjects JF - Neurorehabilitation : an interdisciplinary journal N2 - BACKGROUND: Mirror therapy (MT) was found to improve motor function after stroke, but its neural mechanisms remain unclear, especially in single stroke patients. OBJECTIVES: The following imaging study was designed to compare brain activation patterns evoked by the mirror illusion in single stroke patients with normal subjects. METHODS: Fifteen normal volunteers and five stroke patients with severe arm paresis were recruited. Cerebral activations during movement mirroring by means of a video chain were recorded with functional magnetic resonance imaging (fMRI). Single-subject analysis was performed using SPM 8. RESULTS: For normal subjects, ten and thirteen subjects displayed lateralized cerebral activations evoked by the mirror illusion while moving their right and left hand respectively. The magnitude of this effect in the precuneus contralateral to the seen hand was not dependent on movement speed or subjective experience. Negative correlation of activation strength with age was found for the right hand only. The activation pattern in stroke patients is comparable to that of normal subjects and present in four out of five patients. CONCLUSIONS: In summary, the mirror illusion can elicit cerebral activation contralateral to the perceived hand in the majority of single normal subjects, but not in all of them. This is similar even in stroke patients with severe hemiparesis. KW - Movement KW - mirror illusion KW - imaging KW - mirror therapy KW - stroke Y1 - 2013 U6 - https://doi.org/10.3233/NRE-130999 SN - 1053-8135 SN - 1878-6448 VL - 33 IS - 4 SP - 593 EP - 603 PB - IOS Press CY - Amsterdam ER - TY - THES A1 - Glaubitz, Ulrike T1 - Characterization of different rice (Oryza satvia L.) cultivars under high night temperatures in the vegetative stage Y1 - 2013 CY - Potsdam ER - TY - THES A1 - Dahl, Jan-Ulrik T1 - Characterization of the role of the sulfur carrier protein TusA for molybdenum cofactor biosynthesis in Escherichia coli Y1 - 2013 CY - Potsdam ER - TY - THES A1 - Figueira Martins, Nádia Joana T1 - Characterization of transgenic tobacco lines with altered contents of the chloroplast ATP synthase and Clp protease Y1 - 2013 CY - Potsdam ER - TY - THES A1 - Blankenburg, Stefanie T1 - Charakterisierung der GABAB-Rezeptor Subtypen 1 und 2 der Amerikanischen Großschabe Periplaneta americana T1 - Characterization of GABAB receptor subtypes 1 and 2 of the American Cockroach Periplaneta americana N2 - Die nichtproteinogene Aminosäure GABA (γ-Aminobuttersäure) gilt als der wichtigste inhibitorische Neurotransmitter im Zentralnervensystem von Vertebraten sowie Invertebraten und vermittelt ihre Wirkung u. a. über die metabotropen GABAB-Rezeptoren. Bisher sind diese Rezeptoren bei Insekten nur rudimentär untersucht. Für die Amerikanische Großschabe als etablierter Modellorganismus konnte pharmakologisch eine modulatorische Rolle der GABAB-Rezeptoren bei der Bildung von Primärspeichel nachgewiesen werden. Ziel dieser Arbeit war eine umfassende Charakterisierung der GABAB-Rezeptor-Subtypen 1 und 2 von Periplaneta americana. Unter Verwendung verschiedenster Klonierungsstrategien sowie der Kooperationsmöglichkeit mit der Arbeitsgruppe von Prof. Dr. T. Miura (Hokkaido, Japan) in Hinsicht auf eine dort etablierte P. americana EST-Datenbank gelang die Klonierung von zwei Rezeptor-cDNAs. Die Analyse der abgeleiteten Aminosäuresequenzen auf GB-spezifische Domänen und konservierte Aminosäure-Reste, sowie der Vergleich zu bekannten GB Sequenzen anderer Arten legen nahe, dass es sich bei den isolierten Sequenzen um die GABAB-Rezeptor-Subtypen 1 und 2 (PeaGB1 und PeaGB2) handelt. Für die funktionelle und pharmakologische Charakterisierung des Heteromers aus PeaGB1 und PeaGB2 wurden Expressionskonstrukte für die Transfektion in HEK-flpTM-Zellen hergestellt. Das Heteromer aus PeaGB1 und PeaGB2 hemmt bei steigenden GABA-Konzentrationen die cAMP-Produktion. Die Substanzen SKF97541 und 3-APPA konnten als Agonisten identifiziert werden. CGP55845 und CGP54626 wirken als vollwertige Antagonisten. Das in vitro ermittelte pharmakologische Profil im Vergleich zur Pharmakologie an der isolierten Drüse bestätigt, dass die GABA-Wirkung in der Speicheldrüse tatsächlich von GBs vermittelt wird. Für die immunhistochemische Charakterisierung konnte ein spezifischer polyklonaler Antikörper gegen die extrazelluläre Schleife 2 des PeaGB1 generiert werden. Ein weiterer Antikörper, welcher gegen den PeaGB2 gerichtet ist, erwies sich hingegen nicht als ausreichend spezifisch. Western-Blot-Analysen bestätigen das Vorkommen beider Subtypen im Zentralnervensystem von P. americana. Zudem wird der PeaGB1 in der Speicheldrüse und in den Geschlechtsdrüsen der Schabenmännchen exprimiert. Immunhistochemische Analysen zeigen eine PeaGB1-ähnliche Markierung in den GABAergen Fasern der Speicheldrüse auf. Demnach fungiert der PeaGB1 hier als Autorezeptor. Weiterhin konnte eine PeaGB1-ähnliche Markierung in nahezu allen Gehirnneuropilen festgestellt werden. Auch die akzessorischen Drüsen der Männchen, Pilzdrüse und Phallusdrüse, sind PeaGB1-immunreaktiv. N2 - The non-proteinogenic amino acid GABA (γ-aminobutyric acid) is the major inhibitory neurotransmitter in the central nervous system of vertebrates and invertebrates, and GABA mediates its action among others via metabotropic GABAB receptors (GBs). So far, these receptors are only rudimentary characterized in insects. In the American Cockroach, which is an established model organism, pharmacological studies have pointed out a modulatory role of GBs in the production of primary saliva in the salivary gland. Therefore, the aim of this study is the profound characterization of the GABAB receptor subtypes 1 and 2 of Periplaneta americana. Diverse cloning strategies and the access to a Periplaneta EST-database enabled the cloning of two receptor-cDNAs. The analysis of the deduced amino acid sequences for GB-specific domains and conserved amino acid-residues, and the comparison to known GB-sequences of other species revealed that the sequences correspond to GABAB receptor subtypes 1 and 2 (PeaGB1 and PeaGB2). Next, we functionally and pharmacologically characterized the receptor-heteromer of PeaGB1 and PeaGB2. Therefore, we established expression constructs for the transfection of HEK-flpTM-cells. The PeaGB1/PeaGB2 heteromer inhibits dose-dependently the production of cAMP. The substances SKF97541 and 3-APPA imitate the GABA effect. In contrast, CGP54626 and CGP55845 are considered to be proper antagonists. The comparison of the in vitro with the known pharmacology of isolated glands reveals that GBs indeed mediate the effect of GABA in the salivary gland. For immunohistochemical localization, a specific polyclonal antibody was raised against the extracellular loop 2 of PeaGB1. A second antibody, which was raised against the analogous region of the PeaGB2, must be considered to be non-specific. Western blot analyses demonstrate the localization of both subtypes in the central nervous system of P. americana. Additionally, PeaGB1 is expressed in the salivary gland and in male accessory glands. Immunohistochemical analyses reveal the expression of PeaGB1 in GABAergic nerve fibers of the salivary gland. As a consequence, PeaGB1 must act as an autoreceptor in this organ. A widespread distribution of PeaGB1 in almost all neuropiles was detected in the cockroach brain. In the male accessory glands mushroom gland and phallic (conglobate) gland, an intense PeaGB1-like immunoreactivity was measured. KW - GABA KW - Insekt KW - Pharmakologie KW - Gehirn KW - Speicheldrüse KW - GABA KW - insect KW - pharmacology KW - brain KW - salivary gland Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-69648 ER - TY - THES A1 - Hasdorf, Sebastian T1 - Charakterisierung der Photosynthese in an extreme Standorte angepassten Arabidopsi thaliana Ökotypen und in ribosomalen Tabakmutanten Y1 - 2013 CY - Potsdam ER - TY - JOUR A1 - Gergs, Andre A1 - Zenker, Armin A1 - Grimm, Volker A1 - Preuss, Thomas G. T1 - Chemical and natural stressors combined from cryptic effects to population extinction JF - Scientific reports N2 - In addition to natural stressors, populations are increasingly exposed to chemical pollutants released into the environment. We experimentally demonstrate the loss of resilience for Daphnia magna populations that are exposed to a combination of natural and chemical stressors even though effects on population size of a single stressor were cryptic, i.e. hard to detect statistically. Data on Daphnia population demography and along with model-based exploration of our predator-prey system revealed that direct trophic interactions changed the population size-structure and thereby increased population vulnerability to the toxicant which acts in a size selective manner. Moreover, population vulnerability to the toxicant increases with predator size and predation intensity whereas indirect trait-mediated interactions via predator kairomones may buffer chemical effects to a certain extent. Our study demonstrates that population size can be a poor endpoint for risk assessments of chemicals and that ignoring disturbance interactions can lead to severe underestimation of extinction risk. Y1 - 2013 U6 - https://doi.org/10.1038/srep02036 SN - 2045-2322 VL - 3 IS - 2 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Linklater, Wayne L. A1 - Mayer, Katharina A1 - Swaisgood, Ronald R. T1 - Chemical signals of age, sex and identity in black rhinoceros JF - Animal behaviour N2 - Olfactory communication may be particularly important to black rhinoceros, Diceros bicornis, because they are solitary living and have comparatively poor eyesight but their populations are structured by inter-and intrasexual relationships. Understanding olfactory functions and processes might achieve better conservation management but their study in rhinoceros remains anecdotal or descriptive. Experimental approaches are required but rarely possible as rhinoceros are difficult to observe and manipulate. We measured the olfactory investigation behaviour (duration and frequency of sniffing) of black rhinoceros in four experiments designed to determine the function of chemosignals in dung and urine. A habituationedishabituation trial demonstrated that black rhinoceros discriminated individually distinctive odours from faecal signals (experiment 1). When adults (>6 years old) were presented with dung from conspecifics of different sex and age classes (adult, and subadult from 2 to 4 years old), male dung was investigated more by both sexes, and females investigated subadult dung more (experiment 2). Both dung and urine from the same adult donors were investigated by both sexes, but male dung was investigated more than female dung and female urine more than male urine, although differences were statistically weak (experiment 3). Lastly, fresh faecal samples and those aged 1, 2, 4, 16 and 32 days were similarly investigated, indicating that they still function as olfactory signals. Together the results indicate that dung or urine signalled age, sex and identity to conspecifics and signals may persist as dung decays. Chemosignals are likely to be important to the social and spatial organization of black rhinoceros. KW - black rhinoceros KW - Diceros bicornis var. minor KW - dung KW - faeces KW - hook-lipped rhinoceros KW - individual discrimination KW - olfactory communication KW - signal KW - urine Y1 - 2013 U6 - https://doi.org/10.1016/j.anbehav.2012.12.034 SN - 0003-3472 VL - 85 IS - 3 SP - 671 EP - 677 PB - Elsevier CY - London ER - TY - JOUR A1 - Liang, Wei A1 - Heinrich, Ingo A1 - Simard, Sonia A1 - Helle, Gerhard A1 - Linan, Isabel Dorado A1 - Heinken, Thilo T1 - Climate signals derived from cell anatomy of Scots pine in NE Germany JF - Tree physiology N2 - Tree-ring chronologies of Pinus sylvestris L. from latitudinal and altitudinal limits of the species distribution have been widely used for climate reconstructions, but there are many sites within the temperate climate zone, as is the case in northeastern Germany, at which there is little evidence of a clear climate signal in the chronologies. In this study, we developed long chronologies of several cell structure variables (e. g., average lumen area and cell wall thickness) from P. sylvestris growing in northeastern Germany and investigated the influence of climate on ring widths and cell structure variables. We found significant correlations between cell structure variables and temperature, and between tree-ring width and relative humidity and vapor pressure, respectively, enabling the development of robust reconstructions from temperate sites that have not yet been realized. Moreover, it has been shown that it may not be necessary to detrend chronologies of cell structure variables and thus low-frequency climate signals may be retrieved from longer cell structure chronologies. The relatively extensive resource of archaeological material of P. sylvestris covering approximately the last millennium may now be useful for climate reconstructions in northeastern Germany and other sites in the temperate climate zone. KW - cell structure KW - dendroclimatology KW - Pinus sylvestris KW - quantitative wood anatomy KW - tree rings Y1 - 2013 U6 - https://doi.org/10.1093/treephys/tpt059 SN - 0829-318X SN - 1758-4469 VL - 33 IS - 8 SP - 833 EP - 844 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Plue, Jan A1 - De Frenne, Pieter A1 - Acharya, Kamal P. A1 - Brunet, Jorg A1 - Chabrerie, Olivier A1 - Decocq, Guillaume A1 - Diekmann, Martin A1 - Graae, Bente J. A1 - Heinken, Thilo A1 - Hermy, Martin A1 - Kolb, Annette A1 - Lemke, Isgard A1 - Liira, Jaan A1 - Naaf, Tobias A1 - Shevtsova, Anna A1 - Verheyen, Kris A1 - Wulf, Monika A1 - Cousins, Sara A. O. T1 - Climatic control of forest herb seed banks along a latitudinal gradient JF - Global ecology and biogeography : a journal of macroecology N2 - Aim Seed banks are central to the regeneration strategy of many plant species. Any factor altering seed bank density thus affects plant regeneration and population dynamics. Although seed banks are dynamic entities controlled by multiple environmental drivers, climatic factors are the most comprehensive, but still poorly understood. This study investigates how climatic variation structures seed production and resulting seed bank patterns. Location Temperate forests along a 1900km latitudinal gradient in north-western (NW) Europe. Methods Seed production and seed bank density were quantified in 153 plots along the gradient for four forest herbs with different seed longevity: Geum urbanum, Milium effusum, Poa nemoralis and Stachys sylvatica. We tested the importance of climatic and local environmental factors in shaping seed production and seed bank density. Results Seed production was determined by population size, and not by climatic factors. G.urbanum and M.effusum seed bank density declined with decreasing temperature (growing degree days) and/or increasing temperature range (maximum-minimum temperature). P.nemoralis and S.sylvatica seed bank density were limited by population size and not by climatic variables. Seed bank density was also influenced by other, local environmental factors such as soil pH or light availability. Different seed bank patterns emerged due to differential seed longevities. Species with long-lived seeds maintained constant seed bank densities by counteracting the reduced chance of regular years with high seed production at colder northern latitudes. Main conclusions Seed bank patterns show clear interspecific variation in response to climate across the distribution range. Not all seed banking species may be as well equipped to buffer climate change via their seed bank, notably in short-term persistent species. Since the buffering capacity of seed banks is key to species persistence, these results provide crucial information to advance climatic change predictions on range shifts, community and biodiversity responses. KW - Climate change KW - interspecific variation KW - plant-climate interaction KW - seed longevity KW - seed production KW - temperate deciduous forest KW - temperature Y1 - 2013 U6 - https://doi.org/10.1111/geb.12068 SN - 1466-822X SN - 1466-8238 VL - 22 IS - 10 SP - 1106 EP - 1117 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Dormann, Carsten F. A1 - Elith, Jane A1 - Bacher, Sven A1 - Buchmann, Carsten M. A1 - Carl, Gudrun A1 - Carre, Gabriel A1 - Garcia Marquez, Jaime R. A1 - Gruber, Bernd A1 - Lafourcade, Bruno A1 - Leitao, Pedro J. A1 - Münkemüller, Tamara A1 - McClean, Colin A1 - Osborne, Patrick E. A1 - Reineking, Bjoern A1 - Schröder-Esselbach, Boris A1 - Skidmore, Andrew K. A1 - Zurell, Damaris A1 - Lautenbach, Sven T1 - Collinearity a review of methods to deal with it and a simulation study evaluating their performance JF - Ecography : pattern and diversity in ecology ; research papers forum N2 - Collinearity refers to the non independence of predictor variables, usually in a regression-type analysis. It is a common feature of any descriptive ecological data set and can be a problem for parameter estimation because it inflates the variance of regression parameters and hence potentially leads to the wrong identification of relevant predictors in a statistical model. Collinearity is a severe problem when a model is trained on data from one region or time, and predicted to another with a different or unknown structure of collinearity. To demonstrate the reach of the problem of collinearity in ecology, we show how relationships among predictors differ between biomes, change over spatial scales and through time. Across disciplines, different approaches to addressing collinearity problems have been developed, ranging from clustering of predictors, threshold-based pre-selection, through latent variable methods, to shrinkage and regularisation. Using simulated data with five predictor-response relationships of increasing complexity and eight levels of collinearity we compared ways to address collinearity with standard multiple regression and machine-learning approaches. We assessed the performance of each approach by testing its impact on prediction to new data. In the extreme, we tested whether the methods were able to identify the true underlying relationship in a training dataset with strong collinearity by evaluating its performance on a test dataset without any collinearity. We found that methods specifically designed for collinearity, such as latent variable methods and tree based models, did not outperform the traditional GLM and threshold-based pre-selection. Our results highlight the value of GLM in combination with penalised methods (particularly ridge) and threshold-based pre-selection when omitted variables are considered in the final interpretation. However, all approaches tested yielded degraded predictions under change in collinearity structure and the folk lore'-thresholds of correlation coefficients between predictor variables of |r| >0.7 was an appropriate indicator for when collinearity begins to severely distort model estimation and subsequent prediction. The use of ecological understanding of the system in pre-analysis variable selection and the choice of the least sensitive statistical approaches reduce the problems of collinearity, but cannot ultimately solve them. Y1 - 2013 U6 - https://doi.org/10.1111/j.1600-0587.2012.07348.x SN - 0906-7590 SN - 1600-0587 VL - 36 IS - 1 SP - 27 EP - 46 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Pfestorf, H. A1 - Weiss, L. A1 - Müller, J. A1 - Boch, Steffen A1 - Socher, S. A. A1 - Prati, Daniel A1 - Schöning, Ingo A1 - Weisser, W. A1 - Fischer, M. A1 - Jeltsch, Florian T1 - Community mean traits as additional indicators to monitor effects of land-use intensity On grassland plant diversity JF - Perspectives in plant ecology, evolution and systematics N2 - Semi-natural grasslands, biodiversity hotspots in Central-Europe, suffer from the cessation of traditional land-use. Amount and intensity of these changes challenge current monitoring frameworks typically based on classic indicators such as selected target species or diversity indices. Indicators based on plant functional traits provide an interesting extension since they reflect ecological strategies at individual and ecological processes at community levels. They typically show convergent responses to gradients of land-use intensity over scales and regions, are more directly related to environmental drivers than diversity components themselves and enable detecting directional changes in whole community dynamics. However, probably due to their labor- and cost intensive assessment in the field, they have been rarely applied as indicators so far. Here we suggest overcoming these limitations by calculating indicators with plant traits derived from online accessible databases. Aiming to provide a minimal trait set to monitor effects of land-use intensification on plant diversity we investigated relationships between 12 community mean traits, 2 diversity indices and 6 predictors of land-use intensity within grassland communities of 3 different regions in Germany (part of the German 'Biodiversity Exploratory' research network). By standardization of traits and diversity measures, use of null models and linear mixed models we confirmed (i) strong links between functional community composition and plant diversity, (ii) that traits are closely related to land-use intensity, and (iii) that functional indicators are equally, or even more sensitive to land-use intensity than traditional diversity indices. The deduced trait set consisted of 5 traits, i.e., specific leaf area (SLA), leaf dry matter content (LDMC), seed release height, leaf distribution, and onset of flowering. These database derived traits enable the early detection of changes in community structure indicative for future diversity loss. As an addition to current monitoring measures they allow to better link environmental drivers to processes controlling community dynamics. KW - Biodiversity Exploratories KW - Biological conservation KW - (Semi-natural) Grasslands KW - Plant functional traits KW - Indicators KW - Land-use intensity Y1 - 2013 U6 - https://doi.org/10.1016/j.ppees.2012.10.003 SN - 1433-8319 VL - 15 IS - 1 SP - 1 EP - 11 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Scheffler, Christiane ED - Hermanussen, Michael T1 - Comparative Biology and Human Life History JF - Auxology : Studying Human Growth and Development Y1 - 2013 SN - 978-3-510-65278-5 SP - 38 EP - 41 PB - Schweizerbart Science Publishers CY - Stuttgart ER - TY - JOUR A1 - Benina, Maria A1 - Obata, Toshihiro A1 - Mehterov, Nikolay A1 - Ivanov, Ivan A1 - Petrov, Veselin A1 - Toneva, Valentina A1 - Fernie, Alisdair R. A1 - Gechev, Tsanko S. T1 - Comparative metabolic profiling of Haberlea rhodopensis, Thellungiella halophyla, and Arabidopsis thaliana exposed to low temperature JF - Frontiers in plant science N2 - Haberlea rhodopensis is a resurrection species with extreme resistance to drought stress and desiccation but also with ability to withstand low temperatures and freezing stress. In order to identify biochemical strategies which contribute to Haberlea's remarkable stress tolerance, the metabolic reconfiguration of H. rhodopensis during low temperature (4 degrees C) and subsequent return to optimal temperatures (21 degrees C) was investigated and compared with that of the stress tolerant Thellungiella halophyla and the stress sensitive Arabidopsis thaliana. Metabolic analysis by GC-MS revealed intrinsic differences in the metabolite levels of the three species even at 21 degrees C. H. rhodopensis had significantly more raffinose, melibiose, trehalose, rhamnose, myo-inositol, sorbitol, galactinol, erythronate, threonate, 2-oxoglutarate, citrate, and glycerol than the other two species. A. thaliana had the highest levels of putrescine and fumarate, while T halophila had much higher levels of several amino acids, including alanine, asparagine, beta-alanine, histidine, isoleucine, phenylalanine, serine, threonine, and valine. In addition, the three species responded differently to the low temperature treatment and the subsequent recovery, especially with regard to the sugar metabolism. Chilling induced accumulation of maltose in H. rhodopensis and raffinose in A. thaliana but the raffinose levels in low temperature exposed Arabidopsis were still much lower than these in unstressed Haberlea. While all species accumulated sucrose during chilling, that accumulation was transient in H. rhodopensis and A. thaliana but sustained in T halophila after the return to optimal temperature. Thus, Haberlea's metabolome appeared primed for chilling stress but the low temperature acclimation induced additional stress-protective mechanisms. A diverse array of sugars, organic acids, and polyols constitute Haberlea's main metabolic defence mechanisms against chilling, while accumulation of amino acids and amino acid derivatives contribute to the low temperature acclimation in Arabidopsis and Thellungiella. Collectively, these results show inherent differences in the metabolomes under the ambient temperature and the strategies to respond to low temperature in the three species. KW - Arabidopsis thaliana KW - Haberlea rhodopensis KW - low temperature stress KW - metabolite profiling KW - Thellungiella halophila Y1 - 2013 U6 - https://doi.org/10.3389/fpls.2013.00499 SN - 1664-462X VL - 4 IS - 1 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Massie, Thomas Michael A1 - Ryabov, Alexei A1 - Blasius, Bernd A1 - Weithoff, Guntram A1 - Gaedke, Ursula T1 - Complex transient dynamics of stage-structured populations in response to environmental changes JF - The American naturalist : a bi-monthly journal devoted to the advancement and correlation of the biological sciences N2 - Stage structures of populations can have a profound influence on their dynamics. However, not much is known about the transient dynamics that follow a disturbance in such systems. Here we combined chemostat experiments with dynamical modeling to study the response of the phytoplankton species Chlorella vulgaris to press perturbations. From an initially stable steady state, we altered either the concentration or dilution rate of a growth-limiting resource. This disturbance induced a complex transient response-characterized by the possible onset of oscillations-before population numbers relaxed to a new steady state. Thus, cell numbers could initially change in the opposite direction of the long-term change. We present quantitative indexes to characterize the transients and to show that the dynamic response is dependent on the degree of synchronization among life stages, which itself depends on the state of the population before perturbation. That is, we show how identical future steady states can be approached via different transients depending on the initial population structure. Our experimental results are supported by a size-structured model that accounts for interplay between cell-cycle and population-level processes and that includes resource-dependent variability in cell size. Our results should be relevant to other populations with a stage structure including organisms of higher order. KW - chemostat experiments KW - Chlorella vulgaris KW - environmental changes KW - population dynamics KW - stage structure KW - transient dynamics Y1 - 2013 U6 - https://doi.org/10.1086/670590 SN - 0003-0147 SN - 1537-5323 VL - 182 IS - 1 SP - 103 EP - 119 PB - Univ. of Chicago Press CY - Chicago ER -