TY - JOUR A1 - Fischer, Markus A1 - Stöcklin, J. A1 - Weyand, Anne A1 - Maurer, Katrin T1 - Cultural and biological diversity of grasslands in the Swiss Alps Y1 - 2004 SN - 3-7281-2940-2 ER - TY - JOUR A1 - Witt, Isabell A1 - Zanor, Maria Ines A1 - Müller-Röber, Bernd T1 - Transcription factor function search : how do individual factors regulate agronomical important processes in plants? (Subproject A) Y1 - 2004 SN - 3-00-011587-0 ER - TY - JOUR A1 - Fischer, Markus A1 - Lienert, J. T1 - Experimental inbreeding reduces seed production and germination independent of fragmentation of populations of Swertia perennis Y1 - 2004 ER - TY - JOUR A1 - Meyer, Rhonda C. A1 - Müssig, Carsten A1 - Altmann, Thomas T1 - Genetic Diversity : Creation of novel genetic variants of arabidopsis Y1 - 2004 SN - 3-00-011587-0 ER - TY - JOUR A1 - Ketelhut, Kerstin A1 - Mohasseb, Iman A1 - Scheffler, Christiane A1 - Ketelhut, Reinhard G. T1 - Regular exercise improves risk profile and motor development in early childhood Y1 - 2004 ER - TY - JOUR A1 - Lagus, A. A1 - Suomela, J. A1 - Weithoff, Guntram A1 - Heikkila, K. A1 - Helminen, H. A1 - Sipura, J. T1 - Species-specific differences in phytoplankton responses to N and P enrichments and the N:P ratio in the Archipelago Sea, northern Baltic Sea N2 - A nutrient enrichment experiment was conducted in order to study the role of nitrogen (N), phosphorus (P) and the N:P ratio on the early summer phytoplankton community in the Archipelago Sea, northern Baltic Sea. The phytoplankton community was, in terms of chlorophyll a and total biomass, primarily N-limited, but the individual species varied in their responses to the nutrient supply. The recorded overall N limitation was due to fast growth responses of a few N- limited species such as the diatom Chaetoceros wighamii (Brightwell) and the mixotrophic chrysophyte Uroglena sp. Another dominating diatom, Skeletonema costatum (Greville) Cleve was most clearly P-limited. The N:P ratio had the strongest effect on Uroglena sp., which grew exponentially in the enrichments with a high N:P ratio. This can be explained by the ability of the species to feed on P-rich bacteria, which gives it a competitive advantage in P-limited conditions. The species-specific differences in the responses to the nutrient enrichments can generally be explained by differences in the species physiology and they were consistent with the theory of resource competition. Y1 - 2004 UR - http://plankt.oupjournals.org/cgi/reprint/26/7/779 ER - TY - JOUR A1 - Jeltsch, Florian A1 - Tews, Jörg T1 - Climate change impacts woody plant population dynamics in arid savanna Y1 - 2004 ER - TY - JOUR A1 - Piontek, J. A1 - Winkler, Lars A1 - Bal, M. S. A1 - Lassowski, Birgit A1 - Mueller, Sandra L. A1 - Gast, Klaus A1 - Blasig, Ingolf E. T1 - Investigating of homophilic interactions of the tight junction proteins occludin and claudin-5 Y1 - 2004 ER - TY - JOUR A1 - Stitt, Mark T1 - Gauntlets : Garbon and nutrient signalling : test systems, and metabolite and transcript profiles Y1 - 2004 SN - 3-00-011587-0 ER - TY - JOUR A1 - Eckermann, Nora A1 - Fettke, Jörg A1 - Pauly, Markus A1 - Bazant, Esther A1 - Steup, Martin T1 - Starch-metabolism related isozymes in higher plants Y1 - 2004 ER - TY - JOUR A1 - Sachinidis, A. A1 - Wartenberg, Maria A1 - Sauer, Heinrich A1 - Hescheler, Jürgen T1 - Transcription factors, growth factors and signal cascades capable of priming morphogenesis of heart Y1 - 2004 SN - 1-588- 29113-8 ER - TY - JOUR A1 - Scheible, W. R. A1 - Törjék, Otto A1 - Altmann, Thomas T1 - From markers to cloned genes : map based cloning Y1 - 2004 SN - 3-540-20689-2 ER - TY - JOUR A1 - Jeltsch, Florian A1 - Wiegand, K. A1 - Ward, D. T1 - Seed dispersal by cattle may cause shrub encroachment of Grewia flava on southern Kalahari rangelands Y1 - 2004 ER - TY - JOUR A1 - Jandrig, Burkhard A1 - Seitz, Susanne A1 - Hinzmann, Bernd A1 - Arnold, Wolfgang A1 - Micheel, Burkhard A1 - Koelble, Konrad A1 - Siebert, Reiner A1 - Schwartz, Arnfried A1 - Ruecker, Karin A1 - Schlag, Peter M. A1 - Scherneck, Siegfried A1 - Rosenthal, Andra T1 - ST18 is a breast cancer tumor suppressor gene at human chromosome 8q11.2 N2 - We have identified a gene, ST18 (suppression of tumorigenicity 18, breast carcinoma, zinc-finger protein), within a frequent imbalanced region of chromosome 8q11 as a breast cancer tumor suppressor gene. The ST18 gene encodes a zinc-finger DNA-binding protein with six fingers of the C2HC type (configuration Cys-X5-Cys-X12-His-X4-Cys) and an SMC domain. ST18 has the potential to act as transcriptional regulator. ST18 is expressed in a number of normal tissues including mammary epithelial cells although the level of expression is quite low. In breast cancer cell lines and the majority of primary breast tumors, ST18 mRNA is significantly downregulated. A 160 bp region within the promoter of the ST18 gene is hypermethylated in about 80% of the breast cancer samples and in the majority of breast cancer cell lines. The strong correlation between ST18 promoter hypermethylation and loss of ST18 expression in tumor cells suggests that this epigenetic mechanism is responsible for tumor-specific downregulation. We further show that ectopic ST18 expression in MCF-7 breast cancer cells strongly inhibits colony formation in soft agar and the formation of tumors in a xenograft mouse model Y1 - 2004 UR - http://www.nature.com/cgi-taf/DynaPage.taf?file=/onc/journal/v23/n57/abs/ 1208131a.html&dynoptions=doi1113987275 ER - TY - JOUR A1 - Berger, Dieter A1 - Törjek, Otto A1 - Altmann, Thomas T1 - Establishment of high-efficiency mapping tools Y1 - 2004 SN - 3-00-011587-0 ER - TY - JOUR A1 - van Kleunen, Mark A1 - Ramponi, G. A1 - Schmid, Bernhard T1 - Effects of herbivory simulated by clipping and jasmonic acid on growth and reproduction in Solidago canadensis Y1 - 2004 ER - TY - JOUR A1 - Lehnhardt, Lothar A1 - Pufe, Heidrun A1 - Bauman, Ingrid A1 - Baumann, Guido T1 - Responses of chloroplast thylakoid composition to low temperature and high light stress in callus cultures and in leaves of sugar beet Y1 - 2004 ER - TY - JOUR A1 - van Kleunen, Mark A1 - Lenssen, J. P. M. A1 - Fischer, Markus A1 - de Kroon, H. T1 - Local adaption of the clonal plant Ranunculus reptans to flooding along a small-scale gradient. Y1 - 2004 ER - TY - JOUR A1 - Jeltsch, Florian A1 - Tews, Jörg A1 - Brose, Ulrich A1 - Grimm, Volker A1 - Tielbörger, Katja A1 - Wichmann, Matthias A1 - Schwager, Monika T1 - Animal species diversity driven by habitat heterogeneity/diversity : the importance of keystone structures N2 - In a selected literature survey we reviewed studies on the habitat heterogeneity-animal species diversity relationship and evaluated whether there are uncertainties and biases in its empirical support. We reviewed 85 publications for the period 1960-2003. We screened each publication for terms that were used to define habitat heterogeneity, the animal species group and ecosystem studied, the definition of the structural variable, the measurement of vegetation structure and the temporal and spatial scale of the study. The majority of studies found a positive correlation between habitat heterogeneity/diversity and animal species diversity. However, empirical support for this relationship is drastically biased towards studies of vertebrates and habitats under anthropogenic influence. In this paper we show that ecological effects of habitat heterogeneity may vary considerably between species groups depending on whether structural attributes are perceived as heterogeneity or fragmentation. Possible effects may also vary relative to the structural variable measured. Based upon this, we introduce a classification framework that may be used for across-studies comparisons. Moreover, the effect of habitat heterogeneity for one species group may differ in relation to the spatial scale. In several studies, however, different species groups are closely linked to 'keystone structures' that determine animal species diversity by their presence. Detecting crucial keystone structures of the vegetation has profound implications for nature conservation and biodiversity management. Y1 - 2004 ER - TY - JOUR A1 - Hanisch, Uwe-Karsten A1 - van Rossum, D. A1 - Gast, Klaus A1 - Misselwitz, Rolf A1 - Goldstein, Gundars A1 - Koistinaho, Jari A1 - Möller, Thomas T1 - The microglia-activating potential of thrombin : is the protease able to induce cyto- and chemokines? Y1 - 2004 ER - TY - JOUR A1 - Wacker, Alexander A1 - von Elert, Eric T1 - Food quality controls egg quality of the zebra mussel Dreissena polymorpha : The role of fatty acids N2 - We investigated the investment of adult Dreissena polymorpha to the eggs by sampling mussels monthly from 4- and 15-m water depth. The fatty acid composition of eggs differed significantly between depths and over time. To assess whether temperature and food conditions led to the differences observed for mussels sampled from the two depths, mussels were reared in the laboratory under two different 3-month temperature regimes, simulating the temperature of the lake at 4- and 15-m depth. Possible effects of food quality were tested in each simulation using four diets differing in fatty acid composition: Cryptomonas erosa, Nannochloropsis limnetica [rich in polyunsaturated fatty acids (PUFAs) and long- chained PUFAs (.C18)], Scenedesmus obliquus, and the cyanobacterium Aphanothece sp. (deficient in long-chained PUFAs). In newly released eggs, specific (n-3) and (n-6) long-chained PUFAs increased when these fatty acids were available in the natural seston or in the laboratory diets. Mussels fed organisms deficient in long-chained PUFAs were still able to allocate arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid into eggs, which suggests that minimum levels of particular fatty acids were maintained in eggs by transfer from internal reserves of the female mussels to oocytes. In contrast to the diet, there were no effects of the temperature on the fatty acid composition of eggs. Y1 - 2004 UR - http://aslo.org/lo/toc/vol_49/issue_5/1794.pdf ER - TY - JOUR A1 - Weithoff, Guntram T1 - Vertical niche separation of two consumers (Rotatoria) in an extreme habitat N2 - Herbivore populations are commonly restricted by resource limitation, by predation or a combination of the two. Food supplement experiments are suitable for investigating the extent of food limitation at any given time. The main part of this study was performed in an extremely acidic lake (pH 2.7) where the food web consists of only a few components and potential food sources for herbivores are restricted to two flagellates. Life table experiments proved that Chlamydomonas was a suitable food source whereas Ochromonas was an unsuitable food source. The two flagellates and the two rotifers exhibit a pronounced vertical distribution pattern. In this study, a series of food supplement experiments were performed in order to: (1) quantify and compare potential resource limitation of two primary consumers (Cephalodella hoodi and Elosa worallii, Rotatoria) over time, (2) compare their response at different temperatures, (3) evaluate the effect of having an unsuitable food source alongside a valuable one, (4) estimate the effect of predation on rotifers by Heliozoa, and (5) compare the results with those from other acidic lakes. Additionally, the spatio- temporal population dynamics of both species were observed. The field data confirmed a vertical separation of the two species with E. worallii dominating in the upper water layers, and C. hoodi in the deeper, cooler water layers. The results from the food supplement experiments in which Chlamydomonas served as the supplemented suitable food source showed that the two rotifers were food limited in the epilimnion throughout the season to different extents, with Cephalodella being more severely food limited than Elosa. The experiments at different temperatures provided evidence that Elosa had a higher optimum temperature for growth than Cephalodella. When the unsuitable food algae Ochromonas was added alongside the suitable food source Chlamydomonas, C. hoodi was unaffected but E. worallii was negatively affected. Predation of Heliozoa on rotifers was observed but the total effect on the rotifer dynamics is probably low. The comparison with other lakes showed that resource limitation also occurred in one other lake, although to a lesser extent. Overall, the vertical separation of the two rotifers could be explained by both their differential extent of resource limitation and differential response to temperature. Y1 - 2004 ER - TY - JOUR A1 - Tittel, Jörg A1 - Kamjunke, Norbert T1 - Metabolism of dissolved organic carbon by planktonic bacteria and mixotrophic algae in lake neutralisation experiments N2 - 1. Lakes formed in mining pits often contain high concentrations of dissolved ferric iron and sulphate (e.g. 2 and 16 mmol L)1, respectively) and the pH is buffered between 2.5 and 3.5. Efforts to neutralise their water are based on the stimulation of lake internal, bacterial iron- and sulphate reduction. Electron donors may be supplied by organic carbon compounds or indirectly by enhancement of primary production. Here, we investigated the function of mixotrophic algae, which can potentially supplement or deplete the organic carbon pool, in the carbon metabolism and alkalinity budget of an acidic mining lake. 2. Two weeks after organic substrates had been added in a large in situ mesocosm of 30 m diameter, a bloom of Chlamydomonas occurred, reaching a biovolume of 80 mm3 L)1. Growth experiments using filtered lake water showed that the alga reduced the overall dissolved organic carbon (DOC) concentration despite significant photosynthetic activity. However, when Chlamydomonas were grown together with natural bacterioplankton, net DOC consumption did not increase. 3. Uptake experiments using [14C]-glucose indicated that bacteria dominated glucose uptake and remineralisation. Therefore, the DOC leached in the water column was processed mainly by planktonic bacteria. Leached DOC must be regarded as loss, not transferred by larger organisms to the sediment, where reduction processes take place. 4. From phytoplankton biomass and production 2 years after fertilisation we estimated that pelagic photosynthesis does not supply an electron donor capacity capable of reducing more than 2% of actual stock of acidity per year. We estimated that only the benthic primary production was in a range to compensate for ongoing inputs of iron and sulphate. Y1 - 2004 ER - TY - JOUR A1 - Poerschmann, Jürgen A1 - Spijkerman, Elly A1 - Langer, Uwe T1 - Fatty acid patterns in chlamydomonas sp as a marker for nutritional regimes and temperature under extremely acidic conditions N2 - Fatty acid profiles were used to characterize nutritional pathways in Chlamydomonas sp. isolated from an acidic mining lake (pH 2.7). Surprisingly, profiles of Chlamydomonas sp. grown in the lab under photoautotrophic, mixotrophic, and heterotrophic conditions at in situ deep strata lake water temperatures (8C) were very similar, polyunsaturated fatty acids including a-linolenic acid (18:3x3) and 16:4x3 along with palmitic acid (16:0) being most abundant. Therefore, heterotrophic growth of Chlamydomonas sp. at low temperatures can result in high concentrations of polyunsaturated fatty acids, as previously only described for some psychrophilic bacteria. By contrast, the cultivation of isolated Chlamydomonas sp. at 20C, reflecting surface water temperatures, provided fatty acid patterns characteristic of the nutrition strategy applied: the concentration of polyunsaturated fatty acids decreased when the growth pathway changed from photoautotrophic via mixotrophic to heterotrophic. Total fatty acid concentration also diminished in this order. Principal component analysis confirmed the significance of FA profiling to mirror nutritional pathways. Lake- water analysis revealed low concentrations of dissolved organic carbon, mainly consisting of polymeric fulvic acids that are unable to support heterotrophic growth of Chlamydomonas sp. Polymeric fulvic acids present in the deeper strata of the lake turned out to be formed in situ on the basis of organic monomers including reduced sulfur-containing ones, as revealed by thermochemolysis and pyrolysis. Growth of Chlamydomonas sp. in the deep chlorophyll maximum is therefore assumed to mainly result from photosynthesis, despite very low photon densities. Phytol-including metabolites proved to be significant biomarkers to indicate the nutritional pathway of Chlamydomonas sp. a, x-Dicarboxylic acidsùlight- induced degradation products of unsaturated fatty acidsùappeared to be good indicators of photooxidative alterations to the algal species under study. Y1 - 2004 ER - TY - JOUR A1 - Clegg, Mark R. A1 - Maberly, Stephen C. A1 - Jones, Roger I. T1 - Dominance and compromise in freshwater phytoplanktonic flagellates : the interaction of behavioural preferences for conflicting environmental gradients Y1 - 2004 ER - TY - JOUR A1 - Köchy, Martin A1 - Wilson, Scott D. T1 - Semiarid grassland responses to short-term variation in water availability N2 - Standing crop and species composition in semiarid grassland are linked to long-term patterns of water availability, but grasslands are characterized by large single-season variability in rainfall. We tested whether a single season of altered water availability influenced the proportions of grasses and shrubs in a semiarid grassland near the northern edge of the North American Great Plains. We studied stands of the clonal shrub snowberry (Symphoricarpos occidentalis) and adjacent grassland dominated by the native grasses Stipa spartea and Bouteloua gracilis. Rain was excluded and water supplied in amounts corresponding to years of low, medium, and high rainfall, producing a 2 - 4-fold range in monthly precipitation among water supply treatments. There were ten replicate plots of each water treatment in both snowberry stands and grassland. Grass standing crop increased significantly with water availability in grassland but not inside snowberry stands. Total standing crop and shrub stem density increased significantly with water supply, averaged across both communities. In contrast, water had no effect on shrub standing crop or light penetration. In summary, our finding that water has significant effects on a subset of components of grassland vegetation is consistent with long-term, correlational studies, but we also found that a single season of altered water supply had no effect on other important aspects of the ecosystem. Y1 - 2004 UR - http://springerlink.metapress.com/app/home/ content.asp?wasp=1147bd873d6c4f488659db36d63e080d&referrer=contribution&format=2&page=1&pagecount=7 SN - 1385-0237 ER - TY - JOUR A1 - Spijkerman, Elly A1 - Garcia-Mendoza, E. A1 - Matthijs, H. C. P. A1 - Van Hunnik, E. A1 - Coesel, P. F. M. T1 - Negative effects of P-buffering and pH on photosynthetic activity of planktonic desmid species N2 - The photosynthetic activities of three planktonic desmid species (Staurastrum brachiatum, Staurodesmus cuspidatus var. curvatus, and Staurastrum chaetoceras) were compared after adaptation to medium enriched with either a 20 mM Na+- phosphate (P) or HEPES buffer. Incubations up to 2 d were carried out at pH 6 or 8 under normal air or air enriched with 5 % CO2. Gross maximum photosynthetic rate (Pmax) and growth rate were decreased in both S. brachiatum and Std. cuspidatus at higher pH when using the HEPES buffer and this effect was independent of CO2 concentration, indicating that pH had an inhibitory effect on photosynthesis and growth in these species. The P-buffer at pH 8 caused a large decrease in Pmax and quantum yield for charge separation in photosystem 2 (PS2), compared to HEPES-buffered algae. This effect was very large in both S. brachiatum and Std. cuspidatus, two species characteristic of soft water lakes, but also significant in S. chaetoceras, a species dominant in eutrophic, hard water lakes. The decreased Pmax in P- buffer could not be related to a significant increase in cellular P content known to be responsible for inhibition in isolated chloroplasts. Experiments at pH 6 and 8 showed that two conditions, high pH and high Na+ concentration, both contributed to the decreased Pmax and quantum yield in the desmids. Effects of a P-buffer were less pronounced by using K+-P buffer. The use of P-buffer at pH 8 possibly resulted in high irradiance stress in all species, indicated by damage in the PS2 core complex. In the soft water species pH 8 resulted in increased non-photochemical quenching together with a high de-epoxidation state of the xanthophyll cycle pigments. Y1 - 2004 UR - http://www.springerlink.com/app/home/ contribution.asp?wasp=d7fd2f5af00d494191eaadb905f68db3&referrer=parent&backto=searcharticlesresults,3,7; ER - TY - JOUR A1 - Fischer, Markus A1 - Pfisterer, A. A1 - Joshi, Jasmin Radha A1 - Schmid, Bernhard T1 - Rapid decay of diversity-productivity relationships after invasion of experimental plant communities Y1 - 2004 ER - TY - JOUR A1 - Rohde, P. A1 - Hincha, Dirk K. A1 - Heyer, Arnd G. T1 - Heterosis in the freezing tolerance of crosses between two Arabidopsis thaliana accessions (Columbia-0 and C24) that show differences in non-acclimated and acclimated freezing tolerance Y1 - 2004 SN - 0960-7412 ER - TY - JOUR A1 - Vergin, Anika A1 - Freier, B. A1 - Gzik, Axel T1 - Investigations on effects of plant strengthening products to tri-trophic system field bean (Vicia faba (L.)) - black bean aphid (Aphis fabae Scop.) - lacewing larva (Chrysoperla carnea Steph.) Y1 - 2004 ER - TY - JOUR A1 - Jeltsch, Florian A1 - Wichmann, Matthias A1 - Dean, W. R. J. T1 - Global change challenges the Tawny Eagle (Aquila rapax) : modelling extinction risk with respect to predicted climate and land use changes Y1 - 2004 ER - TY - JOUR A1 - Obel, Nicolai A1 - Usadel, Björn A1 - Choo, Tze Siang A1 - Pauly, Markus T1 - Analysing cell wall biosynthesis to study its role in biotic and abiotic stress reactions Y1 - 2004 SN - 3-00-011587-0 ER - TY - JOUR A1 - Rhoades, E. A1 - Cohen, M. A1 - Gussakovsky, E. A1 - Schuler, Benjamin A1 - Haran, G. T1 - Single molecule protein folding Y1 - 2004 SN - 0006-3495 ER - TY - JOUR A1 - Sauer, Heinrich A1 - Wartenberg, Maria A1 - Sachinidis, A. A1 - Hescheler, Jürgen T1 - The development of the cardiovascular system in embryoid bodies deriverd from embryonic stem cells Y1 - 2004 SN - 1-588- 29113-8 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Wagener, C. T1 - From gene to life Y1 - 2004 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Bier, Frank Fabian T1 - Analytical Biochemistry (Editorial) Y1 - 2004 ER - TY - JOUR A1 - Beissenhirtz, Moritz Karl A1 - Scheller, Frieder W. A1 - Stöcklein, Walter F. M. A1 - Kurth, D. A1 - Möhwald, Helmuth A1 - Lisdat, Fred T1 - Electroactive cytochrome c multilayers within a polyelectrolyte assembly Y1 - 2004 ER - TY - JOUR A1 - Kröning, Steffen A1 - Scheller, Frieder W. A1 - Wollenberger, Ursula A1 - Lisdat, Fred T1 - Myoglobin-Clay Electrode for Nitric Oxide (NO) Detection in Solution Y1 - 2004 ER - TY - JOUR A1 - Lieckfeldt, Elke A1 - Simon-Rosin, Ulrike A1 - Zöller, Daniela A1 - Ebert, Berit A1 - Kehr, Julia A1 - Fisahn, Joachim T1 - Spatio/temporal analysis of gene exression profiles within single cells and specific tissue types of developing Arabidopsis plants Y1 - 2004 SN - 3-00-011587-0 ER - TY - JOUR A1 - Schurr, Frank Martin A1 - Dean, W. R. J. A1 - Milton, Sue J. A1 - Jeltsch, Florian T1 - A conceptual model linking demography of the shrub species Grewia flava to the dynamics of Kalahari savannas N2 - Environmental heterogeneity is a major determinant of plant population dynamics. In semi-arid Kalahari savannas, heterogeneity is created by savanna structure, i.e. by the spatial arrangement and temporal dynamics of woody plant and open grassland microsites. We formulate a conceptual model describing the effects of savanna dynamics on the population dynamics of the animal-dispersed shrub Grewia flava. From empirical results we derive model rules describing effects of savanna structure on several processes in Grewia's life cycle. By formulating the model, we summarise existing information on Grewia demography and identify gaps in this knowledge. Despite a number of such gaps, the model can be used to make certain quantitative predictions. As an example, we apply the model to investigate the role of seed dispersal in Grewia encroachment on rangelands. Model results show that cattle promote encroachment by depositing substantial numbers of seeds in open areas, where Grewia is otherwise dispersal-limited. Finally, we draw some general conclusions about Grewia's life history and population dynamics. Under natural conditions, concentrated seed deposition under woody plants appears to be a key process causing the observed association between Grewia and other woody plants. Furthermore, low rates of recruitment and high adult survival result in slow-motion dynamics of Grewia populations. As a consequence, Grewia populations interact with savanna dynamics on long temporal and short to intermediate spatial scales. Y1 - 2004 ER - TY - JOUR A1 - Schurr, Frank Martin A1 - Bossdorf, Oliver A1 - Milton, Sue J. A1 - Schumacher, J. T1 - Spatial pattern formation in semi-arid shrubland : a priori predicted versus observed pattern characteristics N2 - Ecologists increasingly use spatial statistics to study vegetation patterns. Mostly, however, these techniques are applied in a purely descriptive fashion without a priori statements on the pattern characteristics expected. We formulated such a priori predictions in a study of spatial pattern in a semi-arid Karoo shrubland, South Africa. Both seed dispersal and root competition have been discussed as processes shaping the spatial structure of this community. If either of the two processes dominates pattern formation, patterns within and between shrub functional groups are expected to show distinct deviations from null models. We predicted the type and scale of these deviations and compared predicted to observed pattern characteristics. As predicted by the seed dispersal hypothesis, small-scale co-occurrence within and between groups of colonisers and successors was increased as compared to complete spatially random arrangement of shrubs. The root competition predictions, however, were not met as shrubs of similar rooting depth co- occurred more frequently than expected under random shrub arrangement. Since the distribution of rooting groups to the given shrub locations also failed to match the root competition predictions, there was little evidence for dominance of root competition in pattern formation. Although other processes may contribute to small-scale plant co-occurrence, the sufficient and most parsimonious explanation for the observed pattern is that its formation was dominated by seed dispersal. To characterise point patterns we applied both cumulative (uni- and bivariate K-function) and local (pair- and mark-correlation function) techniques. Based on our results we recommend that future studies of vegetation patterns include local characteristics as they independently describe a pattern at different scales and can be easily related to processes changing with interplant distance in a predictable fashion. Y1 - 2004 ER - TY - JOUR A1 - Warncke, Max A1 - Vogt, Birgit A1 - Ulrich, Jacqueline A1 - von Laer, Meike Dorothee A1 - Beyer, Winfried A1 - Klump, Hannes A1 - Micheel, Burkhard A1 - Sheriff, Ahmed T1 - Efficient in vitro transduction of naive murine B cells with lentiviral vectors N2 - The aim of this study was to determine the impact of lentiviral transduction on primary murine B cells. Studying B cell activities in vivo or using them for tolerance induction requires that the cells remain unaltered in their biological behavior except for expression of the transgene. As we show here, murine B cells can efficiently be transduced by lentiviral, VSV-G-pseudotyped vectors without the necessity of prior activation. Culture with LPS gave enhanced transduction efficiencies but led to the upregulation of CD86 and proliferation of the cells. Transduction of naive B cells by lentiviral vectors was dependent on multiplicity of infection and did not lead to a concomitant activation. Furthermore, the transduced cells could be used for studies in the NOD mouse system without altering the onset of diabetes. We conclude that lentiviral gene transfer into naive B cells is a powerful tool for manipulation of B cells for therapeutic applications. Y1 - 2004 UR - http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WBK-4C707VR- 7&_coverDate=06%2F04%2F2004&_alid=269000954&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=6713&_sort=d&view=c&_acct=C000053886&_v e ER - TY - JOUR A1 - Schenk, Jörg A. A1 - Matyssek, Franziska A1 - Micheel, Burkhard T1 - Interleukin 4 increases the antibody response against Rubisco in mice N2 - The influence of interleukin 4 (IL-4) on antibody titer in serum and spleen culture supernatant in mice immunized with spinach (Spinacia oleracea L.) Rubisco was investigated. Therefore, we boosted one mouse additionally to the antigen with recombinant mouse IL-4. We found that the Rubisco-specific antibody titer in serum as well as in spleen cell culture supernatant was significantly enhanced in the IL-4 mouse. Most of the antibodies were of the IgG1 subclass. After hybridoma generation, Rubisco-specific antibodies were found in more than 95% of the wells tested compared to about 12% of the control mouse. Y1 - 2004 ER - TY - JOUR A1 - Ale-Agha, Nosratollah A1 - Bolay, Adrien A1 - Braun, Uwe A1 - Jage, Horst A1 - Kummer, Volker A1 - Lebeda, Ales A1 - Piatek, Marcin A1 - Shin, Hyeon-Dong A1 - Zimmermannova-Pastircakova, Katarina T1 - Erysiphe catalpae and E. elevata in Europe Y1 - 2004 ER - TY - JOUR A1 - van Kleunen, Mark A1 - Ritland, K. T1 - Estimating heritabilities and genetic correlations with marker-based methods : an experimental test in Mimulus guttatus N2 - The calculation of heritabilities and genetic correlations, which are necessary for predicting evolutionary responses, requires knowledge about the relatedness between individuals. This information is often not directly available, especially not for natural populations, but can be inferred by using molecular markers such as allozymes. Several methods based on inferred relatedness from marker data have been developed to estimate heritabilities and genetic correlations in natural populations. Most methods use maximum-likelihood procedures to assign pairs or groups of individuals to predefined discrete relatedness classes (e.g., half sibs and unrelated individuals). The Ritland method, on the other hand, uses method of moments estimators to estimate pairwise relatedness among individuals as continuous values. We tested both the Ritland method and a maximum-likelihood method by applying them to a greenhouse population consisting of seed families of the herb Mimulus guttatus and comparing the results to the ones from a frequently used standard method based on half-sib families. Estimates of genetic correlations were far from accurate, especially when we used the Ritland method. However, this study shows that even with a few variable allozyme loci, it is possible to get qualitatively good indications about the presence of heritable genetic variation from marker-based methods, even though both methods underestimated it Y1 - 2005 ER - TY - JOUR A1 - Virta, P. A1 - Koch, Andreas A1 - Roslund, M. U. A1 - Mattjus, P. A1 - Kleinpeter, Erich A1 - Kronberg, L. A1 - Sjoholm, R. A1 - Klika, Karel D. T1 - Synthesis, characterisation and theoretical calculations of 2,6-diaminopurine etheno derivatives N2 - Four derivatives of 2,6-diaminopurine (1) were synthesised and characterised. When 1 was reacted with chloroacetaldehyde, 5-aminoimidazo[2,1- i] purine (2), 9-aminoimidazo[2,1-b]purine (3), 9-aminoimidazo[1,2- a]purine (4) and diimidazo[2,1-b: 2', 1'-i]purine (5) were formed. The purified products (3 - 5) were fully characterised by MS, complete NMR assignments as well as fluorescence and UV spectroscopy. The purified, isolated yields of these products ( 3 - 5) varied from 2.5 to 30%. The relative stability of different tautomers was investigated by theoretical calculations. Fluorescence characteristics are also discussed and compared to the starting material 1 and a reference molecule 2-aminopurine Y1 - 2005 SN - 1477-0520 ER - TY - JOUR A1 - Xie, J. A1 - Techritz, S. A1 - Haebel, Sophie A1 - Horn, A. A1 - Neitzel, H. A1 - Klose, J. A1 - Schuelke, M. T1 - A two-dimensional electrophoretic map of human mitochondrial proteins from immortalized lymphoblastoid cell lines: a prerequisite to study mitochondrial disorders in patients N2 - Mitochondrial diseases may be caused by numerous mutations that alter proteins of the respiratory chain and of other metabolic pathways in the mitochondrium. For clinicians this disease group poses a considerable diagnostic challenge due to ambiguous genotype-phenotype relationships. Until now, only 30 % of the mitochondriopathies can be diagnosed at the molecular level. We therefore need a new diagnostic tool that offers a wide view on the mitochondrial proteins. Here, we present a method to generate a high-resolution, large-gel two-dimensional gel electrophoretic (2-DE) map of a purified fraction of mitochondrial proteins from Epstein-Barr virus-immortalized lymphoblastoid cell line (LCL). LCLs can be easily obtained from patients and control subjects in a routine clinical setting. They often express the biochemical phenotype and can be cultured to high cell numbers, sufficient to gain enough purified material for 2- DE. In total we identified 166 mitochondrial proteins. Thirteen proteins were earlier not known to be of mitochondrial origin. Thirty-nine proteins were associated with human diseases ranging from respiratory chain enzyme deficiencies to disorders of P-oxidation and amino acid metabolism. This 2-DE map is intended to be the first step to diagnose mitochondrial diseases at the proteomic level Y1 - 2005 SN - 1615-9853 ER - TY - JOUR A1 - Wichmann, Matthias A1 - Groeneveld, Jürgen A1 - Jeltsch, Florian A1 - Grimm, Volker T1 - Mitigation of climate change impacts on raptors by behavioural adaptation : ecological buffering mechanisms N2 - The predicted climate change causes deep concerns on the effects of increasing temperatures and changing precipitation patterns on species viability and, in turn, on biodiversity. Models of Population Viability Analysis (PVA) provide a powerful tool to assess the risk of species extinction. However, most PVA models do not take into account the potential effects of behavioural adaptations. Organisms might adapt to new environmental situations and thereby mitigate negative effects of climate change. To demonstrate such mitigation effects, we use an existing PVA model describing a population of the tawny eagle (Aquila rapax) in the southern Kalahari. This model does not include behavioural adaptations. We develop a new model by assuming that the birds enlarge their average territory size to compensate for lower amounts of precipitation. Here, we found the predicted increase in risk of extinction due to climate change to be much lower than in the original model. However, this "buffering" of climate change by behavioural adaptation is not very effective in coping with increasing interannual variances. We refer to further examples of ecological "buffering mechanisms" from the literature and argue that possible buffering mechanisms should be given due consideration when the effects of climate change on biodiversity are to be predicted. (c) 2004 Elsevier B.V. All rights reserved Y1 - 2005 SN - 0921-8181 ER - TY - JOUR A1 - Weithoff, Guntram T1 - On the ecology of the rotifer Cephalodella hoodi from an extremely acidic lake N2 - 1. The biovolume-specific carbon content, relative egg volume (a measure of per-offspring reproductive investment), growth and grazing rates, and the gross growth efficiency (GGE) of the rotifer Cephalodella hoodi, isolated from an extremely acidic habitat (pH 2.65), were determined and compared with literature values for rotifers living in circum-neutral habitats in order to reveal potential special features or adaptations related to the extreme habitat of C. hoodi. 2. Of the two dominant phytoflagellates (Ochromonas sp. and Chlamydomonas acidophila) that occur in the natural habitat of C. hoodi, only C. acidophila promoted positive growth and reproduction and, thus, the following results were obtained with C. acidophila as a food alga. 3. The body volume-specific carbon content of C. hoodi is in the range of that found in rotifers from circum-neutral lakes, suggesting that no costly carbon investment, brought about by the thickening of the lorica, for example, was required to withstand low pH. 4. The egg volume of C. hoodi exhibited no phenotypic plasticity dependent on the food concentration and, thus, C. hoodi allocated a constant, absolute amount of energy to each individual offspring. No adaptation to low food densities was found. 5. A dome-shaped type II functional response curve was found to describe the ingestion of Chlamydomonas as a source of food. 6. Compared with other rotifers, C. hoodi had a high threshold and half-saturating food concentration (=low affinity) but also a high maximum growth rate and a relatively high GGE, suggesting no severe adverse effect of low pH Y1 - 2005 SN - 0046-5070 ER - TY - JOUR A1 - Vorgerd, M. A1 - vanderVen, Peter F. M. A1 - Bruchertseifer, V. A1 - Lowe, T. A1 - Kley, R. A. A1 - Schröder, Rolf A1 - Lochmuller, H. A1 - Himmel, Mirko A1 - Koehler, K. A1 - Fürst, Dieter Oswald A1 - Huebner, A. T1 - A mutation in the dimerization domain of filamin C causes a novel type of autosomal dominant myofibrillar myopathy N2 - Myofibrillar myopathy (MFM) is a human disease that is characterized by focal myofibrillar destruction and pathological cytoplasmic protein aggregations. In an extended German pedigree with a novel form of MFM characterized by clinical features of a limb-girdle myopathy and morphological features of MFM, we identified a cosegregating, heterozygous nonsense mutation (8130G -> A; W2710X) in the filamin c gene ( FLNC) on chromosome 7q32.1. The mutation is the first found in FLNC and is localized in the dimerization domain of filamin c. Functional studies showed that, in the truncated mutant protein, this domain has a disturbed secondary structure that leads to the inability to dimerize properly. As a consequence of this malfunction, the muscle fibers of our patients display massive cytoplasmic aggregates containing filamin c and several Z-disk-associated and sarcolemmal proteins Y1 - 2005 SN - 0002-9297 ER -