@article{WallschlaegerBeierBurkartetal.2004, author = {Wallschl{\"a}ger, Hans-Dieter and Beier, Wolfgang and Burkart, Michael and Mrzljak, Jadranka and Oehlschl{\"a}ger, Susanne and Wanner, Manfred}, title = {{\"O}kologische Datenerfassung f{\"u}r Naturschutzbewertung und Monitoring im Offenland}, isbn = {3-540-22449-1}, year = {2004}, language = {de} } @article{SeitzRistowKlemmetal.2004, author = {Seitz, Birgit and Ristow, Michael and Klemm, Gunther and R{\"a}tzel, Stefan and Schulze, Gerhart and Hoffmann, Maik}, title = {Zur Verbreitung der Wildrosen und verwilderten Kulturrosen in Berlin und Brandenburg}, issn = {0724-3111 -}, year = {2004}, language = {de} } @article{AlbrechtHaebelKochetal.2004, author = {Albrecht, Tanja and Haebel, Sophie and Koch, Anke and Krause, Ulrike and Eckermann, Nora and Steup, Martin}, title = {Yeast glycogenin (Glg2p) produced in Escherichia coli is simultaneously glucosylated at two vicinal tyrosin residues but results in a reduced bacterial glycogen accumulation}, year = {2004}, abstract = {Saccharomyces cerevisiae possesses two glycogenin isoforms (designated as Glg1p and Glg2p) that both contain a conserved tyrosine residue, Tyr232. However, Glg2p possesses an additional tyrosine residue, Tyr230 and therefore two potential autoglucosylation sites. Glucosylation of Glg2p was studied using both matrix-assisted laser desorption ionization and electrospray quadrupole time of flight mass spectrometry. Glg2p, carrying a C-terminal (His(6)) tag, was produced in Escherichia coli and purified. By tryptic digestion and reversed phase chromatography a peptide (residues 219-246 of the complete Glg2p sequence) was isolated that contained 4-25 glucosyl residues. Following incubation of Glg2p with UDPglucose, more than 36 glucosyl residues were covalently bound to this peptide. Using a combination of cyanogen bromide cleavage of the protein backbone, enzymatic hydrolysis of glycosidic bonds and reversed phase chromatography, mono- and diglucosylated peptides having the sequence PNYGYQSSPAM were generated. MS/MS spectra revealed that glucosyl residues were attached to both Tyr232 and Tyr230 within the same peptide. The formation of the highly glucosylated eukaryotic Glg2p did not favour the bacterial glycogen accumulation. Under various experimental conditions Glg2p-producing cells accumulated approximately 30\% less glycogen than a control transformed with a Glg2p lacking plasmid. The size distribution of the glycogen and extractable activities of several glycogen-related enzymes were essentially unchanged. As revealed by high performance anion exchange chromatography, the intracellular maltooligosaccharide pattern of the bacterial cells expressing the functional eukaryotic transgene was significantly altered. Thus, the eukaryotic glycogenin appears to be incompatible with the bacterial initiation of glycogen biosynthesis}, language = {en} } @article{PacholskyVakeelHimmeletal.2004, author = {Pacholsky, Dirk and Vakeel, Padmanabhan and Himmel, Mirko and Lowe, T. and Stradal, T. and Rottner, K. and F{\"u}rst, Dieter Oswald and vanderVen, Peter F. M.}, title = {Xin repeats define a novel actin-binding motif}, issn = {0021-9533}, year = {2004}, abstract = {Xin is a protein that is expressed during early developmental stages of cardiac and skeletal muscles. Immunolocalization studies indicated a peripheral localization in embryonic mouse heart, where Xin localizes with beta- catenin and N-cadherin. In adult tissues, Xin is found primarily in the intercalated discs of cardiomyocytes and the myotendinous junctions of skeletal muscle cells, both specialized attachment sites of the myofibrillar ends to the sarcolemma. A large part of the Xin protein consists of unique 16 amino acid repeats with unknown function. We have investigated the characteristics of the Xin repeats by transfection experiments and actin-binding assays and ascertained that, upon expression in cultured cells, these repeats bind to and stabilize the actin-based cytoskeleton. In vitro co- sedimentation assays with skeletal muscle actin indicated that they not only directly bind actin filaments, but also have the capability of arranging microfilaments into networks that sediment upon low-speed centrifugation. Very similar repeats were also found in Xin-repeat protein 2' (XIRP2), a novel protein that seems to be expressed mainly in striated muscles. Human XIRP2 contains 28 Xin repeats with properties identical to those of Xin. We conclude that the Xin repeats define a novel, repetitive actin-binding motif present in at least two different muscle proteins. These Xin- repeat proteins therefore constitute the first two members of a novel family of actin-binding proteins}, language = {en} } @article{Kummer2004, author = {Kummer, Volker}, title = {Vom Seidenbau in Krausnick}, year = {2004}, language = {de} } @article{BoeseGraySimmons2004, author = {Boese, Stefan H. and Gray, Michael A. and Simmons, N. L.}, title = {Volume and non-volume activated anion conductances and their interactions in the renal IMCD}, isbn = {0-387- 23299-0}, year = {2004}, language = {en} } @article{Weithoff2004, author = {Weithoff, Guntram}, title = {Vertical niche separation of two consumers (Rotatoria) in an extreme habitat}, year = {2004}, abstract = {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.}, language = {en} } @article{HilsonAllemeerschAltmannetal.2004, author = {Hilson, Pierre and Allemeersch, Joke and Altmann, Thomas and Aubourg, Sebastien and Avon, Alexandra and Beynon, Jim and Bhalerao, Rishikesh P. and Bitton, Frederique and Caboche, Michel and Cannoot, Bernard and Chardakov, Vasil and Cognet-Holliger, Cecile and Colot, Vincent and Crowe, Mark and Darimont, Caroline and Durinck, Steffen and Eickhoff, Holger and deLongevialle, Andeol Falcon and Farmer, Edward E. and Grant, Murray and Kuiper, Martin T. R. and Lehrach, Hans and Leon, Celine and Leyva, Antonio and Lundeberg, Joakim and Lurin, Claire and Moreau, Yves}, title = {Versatile gene-specific sequence tags for arabidopsis functional genomics : transcript profiling and reserve genetics applications}, year = {2004}, abstract = {Microarray transcript profiling and RNA interference are two new technologies crucial for large-scale gene function studies in multicellular eukaryotes. Both rely on sequence-specific hybridization between complementary nucleic acid strands, inciting us to create a collection of gene-specific sequence tags (GSTs) representing at least 21,500 Arabidopsis genes and which are compatible with both approaches. The GSTs were carefully selected to ensure that each of them shared no significant similarity with any other region in the Arabidopsis genome. They were synthesized by PCR amplification from genomic DNA. Spotted microarrays fabricated from the GSTs show good dynamic range, specificity, and sensitivity in transcript profiling experiments. The GSTs have also been transferred to bacterial plasmid vectors via recombinational cloning protocols. These cloned GSTs constitute the ideal starting point for a variety of functional approaches, including reverse genetics. We have subcloned GSTs on a large scale into vectors designed for gene silencing in plant cells. We show that in planta expression of GST hairpin RNA results in the expected phenotypes in silenced Arabidopsis lines. These versatile GST resources provide novel and powerful tools for functional genomics}, language = {en} } @misc{KoechyWilson2004, author = {K{\"o}chy, Martin and Wilson, Scott D.}, title = {Variation in nitrogen deposition and available soil nitrogen in a forest-grassland ecotone in Canada}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-5768}, year = {2004}, abstract = {Regional variation in nitrogen (N) deposition increases plant productivity and decreases species diversity, but landscape- or local-scale influences on N deposition are less well-known. Using ion-exchange resin, we measured variation of N deposition and soil N availability within Elk Island National Park in the ecotone between grassland and boreal forest in western Canada. The park receives regionally high amounts of atmospheric N deposition (22 kg ha⁻¹ yr⁻¹). N deposition was on average higher ton clayrich luvisols than on brunisols, and areas burned 1 - 15 years previously received more atmospheric N than unburned sites. We suggest that the effects of previous fires and soil type on deposition rate act through differences in canopy structure. The magnitude of these effects varied with the presence of ungulate grazers (bison, moose, elk) and vegetation type (forest, shrubland, grassland). Available soil N (ammonium and nitrate) was higher in burned than unburned sites in the absence of grazing, suggesting an effect of deposition. On grazed sites, differences between fire treatments were small, presumably because the removal of biomass by grazers reduced the effect of fire. Aspen invades native grassland in this region, and our results suggest that fire without grazing might reinforce the expansion of forest into grassland facilitated by N deposition.}, language = {en} } @phdthesis{Usadel2004, author = {Usadel, Bj{\"o}rn}, title = {Untersuchungen zur Biosynthese der pflanzlichen Zellwand = [Identification and characterization of genes involved in plant cell wall synthesis]}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-2947}, school = {Universit{\"a}t Potsdam}, year = {2004}, abstract = {Even though the structure of the plant cell wall is by and large quite well characterized, its synthesis and regulation remains largely obscure. However, it is accepted that the building blocks of the polysaccharidic part of the plant cell wall are nucleotide sugars. Thus to gain more insight into the cell wall biosynthesis, in the first part of this thesis, plant genes possibly involved in the nucleotide sugar interconversion pathway were identified using a bioinformatics approach and characterized in plants, mainly in Arabidopsis. For the computational identification profile hidden markov models were extracted from the Pfam and TIGR databases. Mainly with these, plant genes were identified facilitating the "hmmer" program. Several gene families were identified and three were further characterized, the UDP-rhamnose synthase (RHM), UDP-glucuronic acid epimerase (GAE) and the myo-inositol oxygenase (MIOX) families. For the three-membered RHM family relative ubiquitous expression was shown using variuos methods. For one of these genes, RHM2, T-DNA lines could be obtained. Moreover, the transcription of the whole family was downregulated facilitating an RNAi approach. In both cases a alteration of cell wall typic polysaccharides and developmental changes could be shown. In the case of the rhm2 mutant these were restricted to the seed or the seed mucilage, whereas the RNAi plants showed profound changes in the whole plant. In the case of the six-membered GAE family, the gene expressed to the highest level (GAE6) was cloned, expressed heterologously and its function was characterized. Thus, it could be shown that GAE6 encodes for an enzyme responsible for the conversion of UDP-glucuronic acid to UDP-galacturonic acid. However, a change in transcript level of variuos GAE family members achieved by T-DNA insertions (gae2, gae5, gae6), overexpression (GAE6) or an RNAi approach, targeting the whole family, did not reveal any robust changes in the cell wall. Contrary to the other two families the MIOX gene family had to be identified using a BLAST based approach due to the lack of enough suitable candidate genes for building a hidden markov model. An initial bioinformatic characterization was performed which will lead to further insights into this pathway. In total it was possible to identify the two gene families which are involved in the synthesis of the two pectin backbone sugars galacturonic acid and rhamnose. Moreover with the identification of the MIOX genes a genefamily, important for the supply of nucleotide sugar precursors was identified. In a second part of this thesis publicly available microarray datasets were analyzed with respect to co-responsive behavior of transcripts on a global basis using nearly 10,000 genes. The data has been made available to the community in form of a database providing additional statistical and visualization tools (http://csbdb.mpimp-golm.mpg.de). Using the framework of the database to identify nucleotide sugar converting genes indicated that co-response might be used for identification of novel genes involved in cell wall synthesis based on already known genes.}, subject = {Zellwand}, language = {en} } @article{SachinidisWartenbergSaueretal.2004, author = {Sachinidis, A. and Wartenberg, Maria and Sauer, Heinrich and Hescheler, J{\"u}rgen}, title = {Transcription factors, growth factors and signal cascades capable of priming morphogenesis of heart}, isbn = {1-588- 29113-8}, year = {2004}, language = {en} } @article{WittZanorMuellerRoeber2004, author = {Witt, Isabell and Zanor, Maria Ines and M{\"u}ller-R{\"o}ber, Bernd}, title = {Transcription factor function search : how do individual factors regulate agronomical important processes in plants? (Subproject A)}, isbn = {3-00-011587-0}, year = {2004}, language = {en} } @article{KrylovBeissenhirtzAdamzigetal.2004, author = {Krylov, Andrey V. and Beissenhirtz, Moritz Karl and Adamzig, Holger and Scheller, Frieder W. and Lisdat, Fred}, title = {Thick-film electrodes for measurement of superoxide and hydrogen peroxide based on direct protein-electrode contacts}, year = {2004}, abstract = {Cytochrome c was immobilized on screen-printed thick-film gold electrodes by a self-assembly approach using mixed monolayers of mercaptoundecanoic acid and mercaptoundecanol. Cyclic voltammetry revealed quasi-reversible electrochemical behavior of the covalently fixed protein with a formal potential of +10 mV vs. Ag/AgCl. Polarized at +150 mV vs. Ag/AgCl the electrode was found to be sensitive to superoxide radicals in the range 300-1200 nmol L-1. Compared with metal needle electrodes sensitivity and reproducibility could be improved and combined with the easiness of preparation. This allows the fabrication of disposable sensors for nanomolar superoxide concentrations. By changing the electrode potential the sensor can be switched from response to superoxide radicals to hydrogen peroxide-another reactive oxygen species. H2O2 sensitivity can be provided in the range 10-1000 mumol L-1 which makes the electrode suitable for oxidative stress studies}, language = {en} } @article{HanischVanRossumXieetal.2004, author = {Hanisch, Uwe-Karsten and Van Rossum, Denise and Xie, Yiheng and Misselwitz, Rolf and Auriola, Seppo and Goldstein, Gundars and Koistinaho, Jari and Kettemann, Helmut and M{\"o}ller, Thomas and Gast, Klaus}, title = {The microglia-activating potential of thrombin : the protease is not involved in the induction of proinflammatory cytokines and chemokines}, year = {2004}, abstract = {The serine protease thrombin is known as a blood coagulation factor. Through limited cleavage of proteinase- activated receptors it can also control growth and functions in various cell types, including neurons, astrocytes, and microglia ( brain macrophages). A number of previous studies indicated that thrombin induces the release of proinflammatory cytokines and chemokines from microglial cells, suggesting another important role for the protease beyond hemostasis. In the present report, we provide evidence that this effect is not mediated by any proteolytic or non- proteolytic mechanism involving thrombin proper. Inhibition of the enzymatic thrombin activity did not affect the microglial release response. Instead the cyto-/chemokine-inducing activity solely resided in a high molecular weight protein fraction that could be isolated in trace amounts even from apparently homogenous alpha- and gamma-thrombin preparations. High molecular weight material contained thrombin-derived peptides as revealed by mass spectrometry but was devoid of thrombin-like enzymatic activity. Separated from the high molecular weight fraction by fast protein liquid chromatography, enzymatically intact alpha- and gamma-thrombin failed to trigger any release. Our findings may force a revision of the notion that thrombin itself is a direct proinflammatory release signal for microglia. In addition, they could be relevant for the study of other cellular activities and their assignment to this protease}, language = {en} } @article{HanischvanRossumGastetal.2004, author = {Hanisch, Uwe-Karsten and van Rossum, D. and Gast, Klaus and Misselwitz, Rolf and Goldstein, Gundars and Koistinaho, Jari and M{\"o}ller, Thomas}, title = {The microglia-activating potential of thrombin : is the protease able to induce cyto- and chemokines?}, year = {2004}, language = {en} } @article{SchefflerKetelhutMohassebetal.2004, author = {Scheffler, Christiane and Ketelhut, Kerstin and Mohasseb, Iman and Ketelhut, Reinhard G.}, title = {The influence of an exercise program on body composition, motor and cardiovascular parameters in pre-school children : a longitudinal study}, isbn = {88-87814-25-2}, year = {2004}, language = {en} } @article{FettkeEckermannPoesteetal.2004, author = {Fettke, J{\"o}rg and Eckermann, Nora and Poeste, Simon and Steup, Martin}, title = {The glycan substrate of the cytosolic (Pho 2) phosphorylase isozyme from Pisum sativum L. : identification, linkage analysis and subcellular localization}, issn = {0960-7412}, year = {2004}, abstract = {The subcellular distribution of starch-related enzymes and the phenotype of Arabidopsis mutants defective in starch degradation suggest that the plastidial starch turnover is linked to a cytosolic glycan metabolism. In this communication, a soluble heteroglycan (SHG) from leaves of Pisum sativum L. has been studied. Major constituents of the SHG are galactose, arabinose and glucose. For subcellular location, the SHG was prepared from isolated protoplasts and chloroplasts. On a chlorophyll basis, protoplasts and chloroplasts yielded approximately 70\% and less than 5\%, respectively, of the amount of the leaf-derived SHG preparation. Thus, most of SHG resides inside the cell but outside the chloroplast. SHG is soluble and not membrane-associated. Using membrane filtration, the SHG was separated into a <10 kDa and a >10 kDa fraction. The latter was resolved into two subfractions (I and II) by field-flow fractionation. In the protoplast-derived >10 kDa SHG preparation the subfraction I was by far the most dominant compound. beta-Glucosyl Yariv reagent was reactive with subfraction II, but not with subfraction I. In in vitro assays the latter acted as glucosyl acceptor for the cytosolic (Pho 2) phosphorylase but not for rabbit muscle phosphorylase. Glycosidic linkage analyses of subfractions I and II and of the Yariv reagent reactive glycans revealed that all three glycans contain a high percentage of arabinogalactan-like linkages. However, SHG possesses a higher content of minor compounds, namely glucosyl, mannosyl, rhamnosyl and fucosyl residues. Based on glycosyl residues and glycosidic linkages, subfraction I possesses a more complex structure than subfraction II}, language = {en} } @article{MargWalzBlenau2004, author = {Marg, S. and Walz, Bernd and Blenau, Wolfgang}, title = {The effects of dopamine receptor agonists and antagonists on the secretory rate of cockroach (Periplaneta americana) salivary glands}, issn = {0022-1910}, year = {2004}, abstract = {The acinar salivary glands of the cockroach, Periplaneta americana, are innervated by dopaminergic and serotonergic nerve fibers. Serotonin stimulates the secretion of protein-rich saliva, whereas dopamine causes the production of protein-free saliva. This suggests that dopamine acts selectively on ion-transporting peripheral cells within the acini and the duct cells, and that serotonin acts on the protein-producing central cells of the acini. We have investigated the pharmacology of the dopamine-induced secretory activity of the salivary gland of Periplaneta americana by testing several dopamine receptor agonists and antagonists. The effects of dopamine can be mimicked by the non-selective dopamine receptor agonist 6,7-ADTN and, less effectively, by the vertebrate D1 receptor-selective agonist chloro-APB. The vertebrate D1 receptor-selective agonist SKF 38393 and vertebrate D2 receptor-selective agonist R(-)- TNPA were ineffective. R(+)-Lisuride induces a secretory response with a slower onset and a lower maximal response compared with dopamine-induced secretion. However, lisuride-stimulated glands continue secreting saliva, even after lisuride-washout. Dopamine-induced secretions can be blocked by the vertebrate dopamine receptor antagonists cis(Z)- flupenthixol, chlorpromazine, and S(+)-butaclamol. Our pharmacological data do not unequivocally indicate whether the dopamine receptors on the Periplaneta salivary glands belong to the D1 or D2 subfamily of dopamine receptors, but we can confirm that the pharmacology of invertebrate dopamine receptors is remarkably different from that of their vertebrate counterparts. (C) 2004 Elsevier Ltd. All rights reserved}, language = {en} } @article{SauerWartenbergSachinidisetal.2004, author = {Sauer, Heinrich and Wartenberg, Maria and Sachinidis, A. and Hescheler, J{\"u}rgen}, title = {The development of the cardiovascular system in embryoid bodies deriverd from embryonic stem cells}, isbn = {1-588- 29113-8}, year = {2004}, language = {en} } @article{KleinFeldhahnHarderetal.2004, author = {Klein, Florian and Feldhahn, Niklas and Harder, S. and Wang, Hui and Wartenberg, Maria and Hofmann, W.-K. and Wernet, Peter and Sieber, Reiner and M{\"u}schen, Markus}, title = {The BCR-ABL1 kinase bypasses selection for the expressio of a pre-B cell receptor in pre-B acute lymphoblastic leukemia cells}, year = {2004}, language = {en} } @article{FrischSanter2004, author = {Frisch, D. and Santer, B.}, title = {Temperature-induced responses of a permanent-pond and a temporary-pond cyclopoid copepod : a link to habitat predictability?}, issn = {1522-0613}, year = {2004}, abstract = {Temporary-pond species can be expected to use environmental cues to predict the onset of adverse conditions, while permanent-pond species may be insensitive to such cues. Temperature is such a potential cue in temporary waterbodies, as if fluctuates more widely with decreasing pond size than in deeper permanent ponds. We compared the temperature-induced response of a permanent-pond and a temporary-pond cyclopoid copepod focusing on juvenile development duration, diapause induction and survival during diapause. Nonlinear regression analysis suggested a stronger effect of temperature on the duration of juvenile development in the temporary-pond species. This species also showed a higher and temperature-dependent variation in development duration (highest coefficient of variation 26\%) compared with the permanent species, for which variation was lower and similar at all temperatures (maximal coefficient of variation 6\%). Temperature significantly influenced the induction of diapause in the temporary-pond species, where the percentage of individuals entering diapause increased from 0\% at 5degreesC and 10degreesC to 63\% at 15degreesC and 91\% at 20degreesC. In the permanent-pond species, diapause induction was independent of temperature and was induced in 100\% of experimental specimens. This suggests an obligatory diapause in the permanent-pond species, a type of dormancy that has not been described previously for cyclopoid copepods. Survival during diapause in both species was higher when the diapausing copepodid stage was reached at lower temperatures. At higher temperatures, the temporary-pond species survived longer than the permanent-pond species. These results suggest different temperature optima of the two species. The strategy displayed by the permanent-pond species might be selected for in more stable habitats and may preclude the colonization of temporary ponds. Higher flexibility in life-history traits and the use of temperature as an environmental cue in the temporary-pond species could be favoured in unpredictable habitats}, language = {en} } @phdthesis{Junker2004, author = {Junker, Bj{\"o}rn H.}, title = {Sucrose breakdown in the potato tuber}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0001673}, school = {Universit{\"a}t Potsdam}, year = {2004}, abstract = {In dieser Arbeit wurden verschiedene Ans{\"a}tze verfolgt, um das Verst{\"a}ndnis des Saccharose-zu-St{\"a}rke Stoffwechselweges in sich entwickelnden Kartoffelknollen zu untersuchen. Zun{\"a}chst wurde ein induzierbares Genexpressions-System aus dem Schimmelpilz Aspergillus nidulans f{\"u}r die Untersuchung des Metabolismus von Kartoffelknollen optimiert. Es wurde herausgefunden, dass dieses sogenannte alc system schneller auf Acetaldehyd reagiert als auf Ethanol, und dass Acetaldehyd weniger Seiteneffekte auf den Metabolismus hat. Die optimalen Induktionsbedingungen wurden dann benutzt um die Effekte einer zeitlich kontrollierten zytosolischen Expression einer Hefe-Invertase auf den Metabolismus der Kartoffelknolle zu untersuchen. Die beobachteten Unterschiede zwischen induzierter und konstitutiver Expression der Invertase f{\"u}hrten zu der Feststellung, dass die Glycolyse erst induziert wird nachdem ein ATP-Mangel durch erh{\"o}htes Saccharose-Cycling kreiert wurde. Weiterhin lassen die Ergebnisse darauf schließen, dass Maltose in der Kartoffelknolle eher ein Produkt der Kondensation zweier Glucose-Einheiten ist statt ein Produkt des St{\"a}rke-Abbaus zu sein. Im zweiten Teil dieser Arbeit wurde gezeigt, dass die Expression einer Hefe-Invertase in der Vakuole von Kartoffelknollen {\"a}hnliche Effekte auf deren Metabolismus hat wie die Expression des gleichen Enzymes im Apoplasten. Diese Beobachtung ist ein weiterer Beleg f{\"u}r die Pr{\"a}senz eines Mechanismus, bei dem Saccharose mittels Endozytose in die Vakuole aufgenommen wird anstatt {\"u}ber Transporter direkt ins Zytosol aufgenommen zu werden. Zum Schluß wird ein kinetisches Modell des Saccharose-Abbaus vorgestellt, das in der Lage ist diesen Teil des Stoffwechsels der Kartoffelknolle quantitativ zu simulieren. Weiterhin kann dieses Modell die metabolischen Effekte der Einf{\"u}hrung einer Hefe-Invertase in das Zytosol von Kartoffelknollen mit erstaunlicher Pr{\"a}zision vorhersagen. Zusammengefasst zeigen die Ergebnisse dieser Arbeit, dass induzierbare Genexpression sowie Computermodelle von Stoffwechselwegen n{\"u}tzliche Hilfsmittel f{\"u}r eine Verbesserung des Verst{\"a}ndnisses des Pflanzenmetabolismus sind.}, language = {en} } @phdthesis{Gehmlich2004, author = {Gehmlich, Katja}, title = {Strukturen der Kraft{\"u}bertragung im quergestreiften Muskel : Protein-Protein-Wechselwirkungen und Regulationsmechanismen}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-2576}, school = {Universit{\"a}t Potsdam}, year = {2004}, abstract = {Im Mittelpunkt dieser Arbeit standen Signaltransduktionsprozesse in den Strukturen der Kraft{\"u}bertragung quergestreifter Muskelzellen, d. h. in den Costameren (Zell-Matrix-Kontakten) und den Glanzstreifen (Zell-Zell-Kontakten der Kardiomyozyten).Es ließ sich zeigen, dass sich die Morphologie der Zell-Matrix-Kontakte w{\"a}hrend der Differenzierung von Skelettmuskelzellen dramatisch {\"a}ndert, was mit einer ver{\"a}nderten Proteinzusammensetzung einhergeht. Immunfluoreszenz-Analysen von Skelettmuskelzellen verschiedener Differenzierungsstadien implizieren, dass die Signalwege, welche die Dynamik der Fokalkontakte in Nichtmuskelzellen bestimmen, nur f{\"u}r fr{\"u}he Stadien der Muskeldifferenzierung Relevanz haben k{\"o}nnen. Ausgehend von diesem Befund wurde begonnen, noch unbekannte Signalwege zu identifizieren, welche die Ausbildung von Costameren kontrollieren: In den Vorl{\"a}uferstrukturen der Costamere gelang es, eine transiente Interaktion der Proteine Paxillin und Ponsin zu identifizieren. Biochemische Untersuchungen legen nahe, dass Ponsin {\"u}ber eine Skelettmuskel-spezifische Insertion im Carboxyterminus das Adapterprotein Nck2 in diesen Komplex rekrutiert. Es wird vorgeschlagen, dass die drei Proteine einen tern{\"a}ren Signalkomplex bilden, der die Umbauvorg{\"a}nge der Zell-Matrix-Kontakte kontrolliert und dessen Aktivit{\"a}t von mitogen activated protein kinases (MAPK) reguliert wird.Die Anpassungsvorg{\"a}nge der Strukturen der Kraft{\"u}bertragung an pathologische Situtation (Kardiomyopathien) in der adulten quergestreiften Muskulatur wurden ausgehend von einem zweiten Protein, dem muscle LIM protein (MLP), untersucht. Es konnte gezeigt werden, dass ein mutiertes MLP-Protein, das im Menschen eine hypertrophe Kardiomyopathie (HCM) ausl{\"o}st, strukturelle Defekte aufweist und weniger stabil ist. Weiterhin zeigte dieses mutierte Protein eine verringerte Bindungsf{\"a}higkeit an die beiden Liganden N-RAP und alpha-Actinin. Die molekulare Grundlage der HCM-verursachenden Mutationen im MLP-Gen k{\"o}nnte folglich eine Ver{\"a}nderung der Hom{\"o}ostase im tern{\"a}ren Komplex MLP \– N-RAP \– alpha-Actinin sein. Die Expressionsdaten eines neu generierten monoklonalen MLP-Antik{\"o}rpers deuten darauf hin, dass die Funktionen des MLP nicht nur f{\"u}r die Integrit{\"a}t des Myokards, sondern auch f{\"u}r die der Skelettmuskulatur notwendig sind.}, subject = {Herzmuskelkrankheit}, language = {de} } @article{VaajeKolstadHoustonRaoetal.2004, author = {Vaaje-Kolstad, G. and Houston, Douglas R. and Rao, F. V. and Peter, Martin G. and Synstad, Bjoenar and van Aalten, Daan M. F. and Eijsink, Vincent G. H.}, title = {Structure of the D142N mutant of the family 18 chitinase ChiB from Serratia marcescens and its complex with allosamidin}, issn = {1570-9639}, year = {2004}, abstract = {Catalysis by ChiB, a family 18 chitinase from Serratia marcescens, involves a conformational change of Asp142 which is part of a characteristic D140XD142XE144 sequence motif In the free enzyme Asp142 points towards Asp140, whereas it rotates towards the catalytic acid, Glu144, upon ligand binding. Mutation of Asp142 to Asn reduced k(cat) and affinity for allosamidin, a competitive inhibitor. The X-ray structure of the D142N mutant showed that Asn142 points towards Glu144 in the absence of a ligand. The active site also showed other structural adjustments (Tyr10, Ser93) that had previously been observed in the wild-type enzyme upon substrate binding. The X-ray structure of a complex of D142N with allosamidin, a pseudotrisaccharide competitive inhibitor, was essentially identical to that of the wild-type enzyme in complex with the same compound. Thus, the reduced allosamidin affinity in the mutant is not caused by structural changes but solely by the loss of electrostatic interactions with Asp142. The importance of electrostatics was further confirmed by the pH dependence of catalysis and allosamidin inhibition. The pH-dependent apparent affinities for allosamidin were not correlated with k(cat), indicating that it is probably better to view the inhibitor as a mimic of the oxazolinium ion reaction intermediate than as a transition state analogue. (C) 2003 Elsevier B.V. All rights reserved}, language = {en} } @misc{HoppertReimerKemmlingetal.2004, author = {Hoppert, Michael and Reimer, Rudolph and Kemmling, Anne and Schr{\"o}der, Annekatrin and G{\"u}nzl, Bettina and Heinken, Thilo}, title = {Structure and reactivity of a biological soil crust from a xeric sandy soil in Central Europe}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-5872}, year = {2004}, abstract = {The investigation was designed to explore the structure, composition and activity of a biological soil crust on an acidic, sandy soil from a temperate climate. The crust covers several hundreds of square meters on the hilltop of a large terminal moraine. The conjugate alga Zygogonium ericetorum forms the essential matrix for the crust, a dense web of algal filaments with interspersed lichens and mosses. The crust is composed of three layers, with an uppermost layer consisting nearly entirely of a dense algal mat. In lower layers, a parasitic fungus, penetrating the algal cells, is another important component of the crust community. In this soil crust, photosynthetic and respiratory activity is stabilized at low water activities.}, language = {en} } @article{TewsBlaumJeltsch2004, author = {Tews, J{\"o}rg and Blaum, Niels and Jeltsch, Florian}, title = {Structural and animal species diversity in arid and semi-arid savannas of the southern Kalahari}, year = {2004}, language = {en} } @article{KamjunkeGaedkeTitteletal.2004, author = {Kamjunke, Norbert and Gaedke, Ursula and Tittel, J{\"o}rg and Weithoff, Guntram and Bell, Elanor M.}, title = {Strong vertical differences in the plankton composition of an extremely acidic lake}, year = {2004}, abstract = {Vertical differences in food web structure were examined in an extremely acidic, iron-rich mining lake in Germany (Lake 111; pH 2.6, total Fe 150mg L-1) during the period of stratification. We tested whether or not the seasonal variation of the plankton composition is less pronounced than the differences observed over depth. The lake was strongly stratified in summer, and concentrations of dissolved organic carbon and inorganic carbon were consistently low in the epilimnion but high in the hypolimnion. Oxygen concentrations declined in the hypolimnion but were always above 2mg L-1. Light attenuation did not change over depth and time and was governed by dissolved ferric iron. The plankton consisted mainly of single-celled and filamentous bacteria, the two mixotrophic flagellates Chlamydomonas sp. and Ochromonas sp., the two rotifer species Elosa worallii and Cephalodella hoodi, and Heliozoa as top predators. We observed very few ciliates and rhizopods, and no heterotrophic flagellates, crustaceans or fish. Ochromonas sp., bacterial filaments, Elosa and Heliozoa dominated in the epilimnion whereas Chlamydomonas sp., single-celled bacteria and Cephalodella dominated in the hypolimnion. Single-celled bacteria were controlled by Ochromonas sp. whereas the lack of large consumers favoured a high proportion of bacterial filaments. The primarily phototrophic Chlamydomas sp. was limited by light and CO2 and may have been reduced due to grazing by Ochromonas sp. in the epilimnion. The distribution of the primarily phagotrophic Ochromonas sp. and of the animals seemed to be controlled by prey availability. Differences in the plankton composition were much higher between the epilimnion and hypolimnion than within a particular stratum over time. The food web in Lake 111 was extremely species-poor enabling no functional redundancy. This was attributed to the direct exclusion of species by the harsh environmental conditions and presumably enforced by competitive exclusion. The latter was promoted by the low diversity at the first trophic level which, in turn, was attributed to relatively stable growth conditions and the independence of resource availability (inorganic carbon and light) from algal density. Ecological theory suggests that low functional redundancy promotes low stability in ecosystem processes which was not supported by our data.}, language = {en} } @article{EckermannFettkePaulyetal.2004, author = {Eckermann, Nora and Fettke, J{\"o}rg and Pauly, Markus and Bazant, Esther and Steup, Martin}, title = {Starch-metabolism related isozymes in higher plants}, year = {2004}, language = {en} } @article{JandrigSeitzHinzmannetal.2004, author = {Jandrig, Burkhard and Seitz, Susanne and Hinzmann, Bernd and Arnold, Wolfgang and Micheel, Burkhard and Koelble, Konrad and Siebert, Reiner and Schwartz, Arnfried and Ruecker, Karin and Schlag, Peter M. and Scherneck, Siegfried and Rosenthal, Andra}, title = {ST18 is a breast cancer tumor suppressor gene at human chromosome 8q11.2}, year = {2004}, abstract = {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}, language = {en} } @article{BistolasChristensonRuzgasetal.2004, author = {Bistolas, Nikitas and Christenson, A. and Ruzgas, T. and Jung, Christiane and Scheller, Frieder W. and Wollenberger, Ursula}, title = {Spectroelectrochemistry of cytochrome P450cam}, year = {2004}, abstract = {The spectroelectrochemistry of camphor-bound cytochrome P450cam (P450cam) using gold electrodes is described. The electrodes were modified with either 4,4'-dithiodipyridin or sodium dithionite. Electrolysis of P450cam was carried out when the enzyme was in solution, while at the same time UV visible absorption spectra were recorded. Reversible oxidation and reduction could be observed with both 4,4'-dithiodipyridin and dithionite modified electrodes. A formal potential (E-0') of -373 mV vs Ag/AgCl 1 M KCl was determined. The spectra of P450cam complexed with either carbon monoxide or metyrapone, both being inhibitors of P450 catalysis, clearly indicated that the protein retained its native state in the electrochemical cell during electrolysis. (C) 2003 Elsevier Inc. All rights reserved}, language = {en} } @article{LagusSuomelaWeithoffetal.2004, author = {Lagus, A. and Suomela, J. and Weithoff, Guntram and Heikkila, K. and Helminen, H. and Sipura, J.}, title = {Species-specific differences in phytoplankton responses to N and P enrichments and the N:P ratio in the Archipelago Sea, northern Baltic Sea}, year = {2004}, abstract = {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.}, language = {en} } @article{MoraMaciasVateretal.2004, author = {Mora, Emanuel C. and Macias, S. and Vater, Marianne and Coro, Frank and Kossl, Manfred}, title = {Specializations for aerial hawking in the echolocation system of Molossus molossus (Molossidae, Chiroptera)}, issn = {0340-7594}, year = {2004}, abstract = {While searching for prey, Molossus molossus broadcasts narrow-band calls of 11.42 ms organized in pairs of pulses that alternate in frequency. The first signal of the pair is at 34.5 kHz, the second at 39.6 kHz. Pairs of calls with changing frequencies were only emitted when the interpulse intervals were below 200 ms. Maximum duty cycles during search phase are close to 20\%. Frequency alternation of search calls is interpreted as a mechanism for increasing duty cycle and thus the temporal continuity of scanning, as well as increasing the detection range. A neurophysiological correlate for the processing of search calls was found in the inferior colliculus. 64\% of neurons respond to frequencies in the 30- to 40-kHz range and only in this frequency range were closed tuning curves found for levels below 40 dB SPL. In addition, 15\% of the neurons have double-tuned frequency-threshold curves with best thresholds at 34 and 39 kHz. Differing from observations in other bats, approach calls of M. molossus are longer and of higher frequencies than search calls. Close to the roost, the call frequency is increased to 45.049.8 kHz and, in addition, extremely broadband signals are emitted. This demonstrates high plasticity of call design}, language = {en} } @article{LieckfeldtSimonRosinZoelleretal.2004, author = {Lieckfeldt, Elke and Simon-Rosin, Ulrike and Z{\"o}ller, Daniela and Ebert, Berit and Kehr, Julia and Fisahn, Joachim}, title = {Spatio/temporal analysis of gene exression profiles within single cells and specific tissue types of developing Arabidopsis plants}, isbn = {3-00-011587-0}, year = {2004}, language = {en} } @article{Baumann2004, author = {Baumann, Otto}, title = {Spatial pattern of nonmuscle myosin-II distribution during the development of the Drosophila compound eye and implications for retinal morphogenesis}, year = {2004}, abstract = {Nonmuscle myosin-II is a motor protein that drives cell movement and changes in cell shape during tissue and organ development. This study has determined he dynamic changes in myosin-II distribution during Drosophila compound eye morphogenesis. In photoreceptor neurons, myosin-II is undetectable at the apical domain throughout the first half of pupal life, at which time this membrane domain is involuted into the epithelium and progresses toward the retinal floor. Myosin-II is deployed at the apical surface at about 60\% of pupal development, once the developing rhabdomeres reach the retinal floor. Subsequently, myosin-II becomes restricted to two stripes at the sides of the developing rhabdomere, adopting its final position within the visual cells R1-6; here, myosin-II is associated with a set of actin filaments that extend alongside the rhabdomeres. At the midpupal stage, myosin-II is also incorporated into stress-fiber-like arrays within the basal endfeet of the pigment cells that then change their shape. This spatiotemporal pattern of myosin- II localization and the morphological defects observed in the eyes of a myosin-II mutant suggest that the myosin-II/F- actin system is involved in the alignment of the rhabdomeres within the retina and in the flattening of the retinal floor. The observation that the myosin-II/F-actin arrays are incomplete or disorganized in R7/R8 and in rhodopsin-1-null R1-6 suggests further that the establishment and stability of this cytoskeletal system depend on rhodopsin-1 expression. (C) 2004 Elsevier Inc. All rights reserved}, language = {en} } @article{SchurrBossdorfMiltonetal.2004, author = {Schurr, Frank Martin and Bossdorf, Oliver and Milton, Sue J. and Schumacher, J.}, title = {Spatial pattern formation in semi-arid shrubland : a priori predicted versus observed pattern characteristics}, year = {2004}, abstract = {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.}, language = {en} } @article{RhoadesCohenGussakovskyetal.2004, author = {Rhoades, E. and Cohen, M. and Gussakovsky, E. and Schuler, Benjamin and Haran, G.}, title = {Single molecule protein folding}, issn = {0006-3495}, year = {2004}, language = {en} } @article{MickEggertHeinemannetal.2004, author = {Mick, V. and Eggert, K. and Heinemann, B. and Geister, S. and Paulsen, H.}, title = {Single amino acids in the lumenal loop domain influence the stability of the major light-harvesting chlorophyll alb complex}, issn = {0006-2960}, year = {2004}, abstract = {The major light-harvesting complex of photosystem II (LHCIIb) is one of the most abundant integral membrane proteins. It greatly enhances the efficiency of photosynthesis in green plants by binding a large number of accessory pigments that absorb light energy and conduct it toward the photosynthetic reaction centers. Most of these pigments are associated with the three transmembrane and one amphiphilic a helices of the protein. Less is known about the significance of the loop domains connecting the a helices for pigment binding. Therefore, we randomly exchanged single amino acids in the lumenal loop domain of the bacterially expressed apoprotein Lhcb1 and then reconstituted the mutant protein with pigments in vitro. The resulting collection of mutated recombinant LHCIIb versions was screened by using a 96-well-format plate-based procedure described previously [Heinemann, B., and Paulsen, H. (1999) Biochemistry 38, 14088- 14093], enabling us to test several thousand mutants for their ability to form stable pigment-protein complexes in vitro. At least one-third of the positions in the loop domain turned out to be sensitive targets; i.e., their exchange abolished formation of LHCIIb in vitro. This confirms our earlier notion that the LHCIIb loop domains contribute more specifically to complex formation and/or stabilization than by merely connecting the alpha helices. Among the target sites, glycines and hydrophilic amino acids are more prominently represented than hydrophobic ones. Specifically, the exchange of any of the three acidic amino acids in the lumenal loop abolishes reconstitution of stable pigment-protein complexes, suggesting that ionic interactions with other protein domains are important for correct protein folding or complex stabilization. One hydrophobic amino acid, tryptophan in position 97, has been hit repeatedly in independent mutation experiments. From the LHCIIb structure and previous mutational analyses. we propose a stabilizing interaction between this amino acid and F195 near the C-proximal end of the third transmembrane helix}, language = {en} } @article{SchmidtWalz2004, author = {Schmidt, R. and Walz, Bernd}, title = {Serotonin and histamine produce different spatiotemporal Ca2+ signals in blowfly salivary glands}, issn = {0171-9335}, year = {2004}, language = {en} } @article{KoechyWilson2004, author = {K{\"o}chy, Martin and Wilson, Scott D.}, title = {Semiarid grassland responses to short-term variation in water availability}, issn = {1385-0237}, year = {2004}, abstract = {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.}, language = {en} } @article{JeltschWiegandWard2004, author = {Jeltsch, Florian and Wiegand, K. and Ward, D.}, title = {Seed dispersal by cattle may cause shrub encroachment of Grewia flava on southern Kalahari rangelands}, year = {2004}, language = {en} } @article{JeltschTewsSchurr2004, author = {Jeltsch, Florian and Tews, J{\"o}rg and Schurr, Frank Martin}, title = {Seed dispersal by cattle may cause shrub encroachment of Grewia flava on southern Kalahari rangelands}, year = {2004}, abstract = {Shrub encroachment, i.e. the increase in woody plant cover, is a major concern for livestock farming in southern Kalahari savannas. We developed a grid-based computer model simulating the population dynamics of Grewia flava, a common, fleshy-fruited encroaching shrub. In the absence of large herbivores, seeds of Grewia are largely deposited in the sub-canopy of Acacia erioloba. Cattle negate this dispersal limitation by browsing on the foliage of Grewia and dispersing seeds into the grassland matrix. In this study we first show that model predictions of Grewia cover dynamics are realistic by comparing model output with shrub cover estimates obtained from a time series of aerial photographs. Subsequently, we apply a realistic range of intensity of cattle-induced seed dispersal combined with potential precipitation and fire scenarios. Based on the simulation results we suggest that cattle may facilitate shrub encroachment of Grewia. The results show that the severity of shrub encroachment is governed by the intensity of seed dispersal. For a high seed dispersal intensity without fire (equivalent to a high stocking rate) the model predicts 56\% shrub cover and 85\% cell cover after 100 yr. With fire both recruitment and shrub cover are reduced, which may, under moderate intensities, prevent shrub encroachment. Climate change scenarios with two-fold higher frequencies of drought and wet years intensified shrub encroachment rates, although long-term mean of precipitation remained constant. As a management recommendation we suggest that shrub encroachment on rangelands may be counteracted by frequent fires and controlling cattle movements to areas with a high proportion of fruiting Grewia shrubs}, language = {en} } @article{UsadelKuschinskyRossoetal.2004, author = {Usadel, Bj{\"o}rn and Kuschinsky, Anja M. and Rosso, Mario G. and Eckermann, Nora and Pauly, Markus}, title = {RHM2 is involved in mucilage pectin synthesis and is required for the development of the seed coat in Arabidopsis}, year = {2004}, abstract = {Pectins are major components of primary plant cell walls and the seed mucilage of Arabidopsis. Despite progress in the structural elucidation of pectins, only very few enzymes participating in or regulating their synthesis have been identified. A first candidate gene involved-in the synthesis of pectinaceous rhamnogalacturonan I is RHM2, a putative plant ortholog to NDP-rhamnose biosynthetic enzymes in bacteria. Expression studies with a promoter beta-glucuronidase construct and reverse transcription PCR data show that RHM2 is expressed ubiquitously. Rhm2 T-DNA insertion mutant lines were identified using a reverse genetics approach. Analysis of the rhm2 seeds by various staining methods and chemical analysis of the mucilage revealed a strong reduction of rhamnogalacturonan I in the mucilage and a decrease of its molecular weight. In addition, scanning electron microscopy of the seed surface indicated a distorted testa morphology, illustrating not only a structural but also a developmental role for RGI or rhamnose metabolism in proper testa formation}, language = {en} } @article{LehnhardtPufeBaumanetal.2004, author = {Lehnhardt, Lothar and Pufe, Heidrun and Bauman, Ingrid and Baumann, Guido}, title = {Responses of chloroplast thylakoid composition to low temperature and high light stress in callus cultures and in leaves of sugar beet}, year = {2004}, language = {en} } @article{KohlerMuellerRoeber2004, author = {Kohler, B. and M{\"u}ller-R{\"o}ber, Bernd}, title = {Remote control - cell and organ communication within plants}, year = {2004}, language = {en} } @article{DamesSchmidtWalzetal.2004, author = {Dames, Petra and Schmidt, R. and Walz, Bernd and Baumann, Otto}, title = {Regulation of vacuolar-type H+-ATPase (vATPase) in blowfly salivary glands}, issn = {0171-9335}, year = {2004}, language = {en} } @phdthesis{Vigeolas2004, author = {Vigeolas, Helene}, title = {Regulation of triacylglycerol biosynthesis in developing seeds of Brassica napus L. and Arabidopsis thaliana (L.) Heyn}, pages = {108 S. : graph. Darst.}, year = {2004}, language = {en} } @article{KetelhutMohassebScheffleretal.2004, author = {Ketelhut, Kerstin and Mohasseb, Iman and Scheffler, Christiane and Ketelhut, Reinhard G.}, title = {Regular exercise improves risk profile and motor development in early childhood}, year = {2004}, language = {en} } @article{FischerPfistererJoshietal.2004, author = {Fischer, Markus and Pfisterer, A. and Joshi, Jasmin Radha and Schmid, Bernhard}, title = {Rapid decay of diversity-productivity relationships after invasion of experimental plant communities}, year = {2004}, language = {en} } @article{JeltschHansenTackmannetal.2004, author = {Jeltsch, Florian and Hansen, Frank and Tackmann, K. and Staubach, C. and Thulke, Hans-Hermann}, title = {Processes leading to a spatial aggregation of Echinococcus multilocularis in its natural intermediate host Microtus arvalis}, year = {2004}, abstract = {The small fox tapeworm (Echinococcus multilocularis) shows a heterogeneous spatial distribution in the intermediate host (Microtus arvalis). To identify the ecological processes responsible for this heterogeneity, we developed a spatially explicit simulation model. The model combines individual-based (foxes, Vulpes vulpes) and grid- based (voles) techniques to simulate the infections in both intermediate and definite host. If host populations are homogeneously mixed, the model reproduces field data for parasite prevalence only for a limited number of parameter combinations. As ecological parameters inevitably vary to a certain degree, we discarded the homogeneous mixing model as insufficient to gain insight into the ecology of the fox tapeworm cycle. We analysed five different model scenarios, each focussing on an ecological process that might be responsible for the heterogeneous spatial distribution of E multilocularis in the intermediate host. Field studies revealed that the prevalence ratio between intermediate and definite host remains stable over a wide range of ecological conditions. Thus, by varying the parameters in simulation experiments, we used the robustness of the agreement between field data and model output as quality criterion for the five scenarios. Only one of the five scenarios was found to reproduce the prevalence ratio over a sufficient range of parameter combinations. In the accentuated scenario most tapeworm eggs die due to bad environmental conditions before they cause infections in the intermediate host. This scenario is supported by the known sensitivity of tapeworm eggs to high temperatures and dry conditions. The identified process is likely to lead to a heterogeneous availability of infective eggs and thus to a clumped distribution of infected intermediate hosts. In conclusion, areas with humid conditions and low temperatures must be pointed out as high risk areas for human exposure to E. multilocularis eggs as well. (C) 2004 on behalf of Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved}, language = {en} } @article{vanKleunenRitland2004, author = {van Kleunen, Mark and Ritland, K.}, title = {Predicting evolution of floral traits associated with mating system in a natural plant population}, issn = {1010- 061x}, year = {2004}, abstract = {Evolution of floral traits requires that they are heritable, that they affect fitness, and that they are not constrained by genetic correlations. These prerequisites have only rarely been examined in natural populations. For Mimulus guttatus, we found by using the Riska-method that corolla width, anther length, ovary length and number of red dots on the corolla were heritable in a natural population. Seed production (maternal fitness) was directly positively affected by corolla width and anther size, and indirectly so by ovary length and number of red dots on the corolla. The siring success (paternal fitness), as estimated from allozyme data, was directly negatively affected by anther-stigma separation, and indirectly so by the corolla length-width ratio. Genetic correlations, estimated with the Lynch-method, were positive between floral size measures. We predict that larger flowers with larger reproductive organs, which generally favour outcrossing, will evolve in this natural population of M. guttatus}, language = {en} } @article{DiezTauerSchulz2004, author = {Diez, Isabel and Tauer, Klaus and Schulz, Burkhard}, title = {Polypyrrole tubes via casting of pyrrole-beta-naphthalenesulfonic acid rods}, issn = {0303-402X}, year = {2004}, abstract = {A comprehensive study gives experimental evidence that a complex made from pyrrole and beta-naphthalenesulfonic acid in a molar composition of 3:1 acts as morphological precursor in the subsequent oxidative polymerization of pyrrole initiated with ammonium peroxodisulfate. The precursor complex itself is unable to polymerize but its outer parallelepipedal shape with a high aspect ratio is templated in the inner surface of the formed conducting polypyrrole tubes}, language = {en} } @article{ModlerFabianSokolowskietal.2004, author = {Modler, Andreas Johannes and Fabian, H. and Sokolowski, F. and Lutsch, G. and Gast, Klaus and Damaschun, Gregor}, title = {Polymerization of proteins into amyloid protofibrils shares common critical oligomeric states but differs in the mechanisms of their formation}, year = {2004}, abstract = {Amyloid protofibril formation of phosphoglycerate kinase (PGK) and Syrian hamster prion protein (SHaPrP(90- 232)) were investigated by static and dynamic light scattering, size exclusion chromatography and electron microscopy. Changes in secondary structure were monitored by Fourier transform infrared spectroscopy and by circular dichroism. Protofibril formation of the two proteins is found to be a two-stage process. At the beginning, an ensemble of critical oligomers is built lip. These critical oligomeric states possess a predominant beta-sheet structure and do not interact considerably with monomers. Initial oligomerization and transition to beta-sheet structure are coupled events differing in their details for both proteins. Intermediate oligomeric states (dimers, trimers, etc.) are populated in case of PGK, whereas SHaPrP(90-232) behaves according to oil apparent two-state reaction between monomers and octamers rich in beta- structure with a reaction order varying between 2 and 4. All oligomers coalesce to PGK protofibrils in the second stage, while SHaPrP(90-232) protofibrils are only formed by a subpopulation. The rates of both growth stages can be tuned in case of PGK by different salts preserving the underlying generalized diffusion-collision mechanism. The different kinetics of the early misfolding and oligomerization events of the two proteins argue against a common mechanism of protofibril formation. A classification scheme for misassembly, mechanisms of proteins based on energy landscapes is presented. It includes scenarios of downhill polymerization to which protofibril formation of PGK and SHaPrP(90-232) belong}, language = {en} } @article{RitteScharfEckermannetal.2004, author = {Ritte, Gerhard and Scharf, Anke and Eckermann, Nora and Haebel, Sophie and Steup, Martin}, title = {Phosphorylation of transitory starch is increased during degradation}, year = {2004}, abstract = {The starch excess phenotype of Arabidopsis mutants defective in the starch phosphorylating enzyme glucan, water dikinase (EC 2.7.9.4) indicates that phosphorylation of starch is required for its degradation. However, the underlying mechanism has not yet been elucidated. In this study, two in vivo systems have been established that allow the analysis of phosphorylation of transitory starch during both biosynthesis in the light and degradation in darkness. First, a photoautotrophic culture of the unicellular green alga Chlamydomonas reinhardtii was used to monitor the incorporation of exogenously supplied P-32 orthophosphate into starch. Illuminated cells incorporated P-32 into starch with a constant rate during 2 h. By contrast, starch phosphorylation in darkened cells exceeded that in illuminated cells within the first 30 min, but subsequently phosphate incorporation declined. Pulse-chase experiments performed with P-32/P-31 orthophosphate revealed a high turnover of the starch-bound phosphate esters in darkened cells but no detectable turnover in illuminated cells. Secondly, leaf starch granules were isolated from potato (Solanum tuberosum) plants grown under controlled conditions and glucan chains from the outer granule layer were released by isoamylase. Phosphorylated chains were purified and analyzed using high performance anion-exchange chromatography and matrix-assisted laser desorption/ionization mass spectrometry. Glucans released from the surface of starch granules that had been isolated from darkened leaves possessed a considerably higher degree of phosphorylation than those prepared from leaves harvested during the light period. Thus, in the unicellular alga as well as in potato leaves, net starch degradation is accompanied with an increased phosphorylation of starch}, language = {en} } @article{KleuserStoeckleinPieperFuerstetal.2004, author = {Kleuser, U. and St{\"o}cklein, Walter F. M. and Pieper-F{\"u}rst, U. and Scheller, Frieder W.}, title = {Partikelverst{\"a}rkte Oberfl{\"a}chenplasmonresonanz f{\"u}r die Quantifizierung von Matrix Metalloproteinase-2}, year = {2004}, language = {de} } @article{ProchnowBrunkSegert2004, author = {Prochnow, Annette and Brunk, Ingo and Segert, Astrid}, title = {Offenhaltung durch M{\"a}hen und R{\"a}umen bzw. Mulchen}, isbn = {3-540-22449-1}, year = {2004}, language = {de} } @article{WannerBurkartHinrichsenetal.2004, author = {Wanner, Manfred and Burkart, Bettina and Hinrichsen, Arne and Prochnow, Annette and Schlauderer, Ralf and Wiesener, Cornelia and Zierke, Irene and Xylander, Willi E. R.}, title = {Offenhaltung durch mechanische Bodenfreilegung}, isbn = {3-540-22449-1}, year = {2004}, language = {de} } @article{WannerAndersBrunketal.2004, author = {Wanner, Manfred and Anders, Kenneth and Brunk, Ingo and Burkart, Bettina and van Dorsten, Petra and F{\"u}rstenau, Stefan and Oehlschl{\"a}ger, Susanne and Prochnow, Annette and Wiesener, Cornelia and Xylander, Willi E. R.}, title = {Offenhaltung durch Feuer}, isbn = {3-540-22449-1}, year = {2004}, language = {de} } @article{RistowSeitz2004, author = {Ristow, Michael and Seitz, Birgit}, title = {Neue Fundorte - Best{\"a}tigungen - Verluste (299 - 323)}, issn = {1617-5506}, year = {2004}, language = {de} } @article{SpijkermanGarciaMendozaMatthijsetal.2004, author = {Spijkerman, Elly and Garcia-Mendoza, E. and Matthijs, H. C. P. and Van Hunnik, E. and Coesel, P. F. M.}, title = {Negative effects of P-buffering and pH on photosynthetic activity of planktonic desmid species}, year = {2004}, abstract = {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.}, language = {en} } @article{KonoldAndersBurkartetal.2004, author = {Konold, Werner and Anders, Kenneth and Burkart, Bettina and Schlauderer, Ralf and Segert, Astrid and Zierke, Irene}, title = {Naturschutz auf ehemaligen Truppen{\"u}bungspl{\"a}tzen: eine abschließende Betrachtung}, isbn = {3-540-22449-1}, year = {2004}, language = {de} } @article{HeinkenZippel2004, author = {Heinken, Thilo and Zippel, Elke}, title = {Natural re-colonization of experimental gaps by terricolous bryophytes in Central European pine forests}, issn = {0029-5035}, year = {2004}, abstract = {In northeastern German pine forests we studied re-colonization patterns of experimental gaps by four dominant bryophyte species (Dicranum scoparium, Hypnum jutlandicum, Pleurozium schreberi and Scleropodium purum) over three years. Both vegetation and litter layer were removed on 1 m(2) plots within +/- pure colonies of the experimental species, while the humus layer was left intact. All plots were vegetatively re-colonized by the species which was dominant before gap creation. Three mechanisms of re-colonization occurred and interacted: (1) advance of surrounding shoots from the edge into the gaps by clonal growth, (2) dispersal of detached single shoots as well as larger clumps of multiple shoots into the plots, resulting in new colonies by continuing growth, and (3) regeneration from a soil diaspore bank consisting of seemingly dead stem fragments in the humus layer of the gaps. Scleropodium purum, which occurs at locations with good water and nutrient supply, displayed the most rapid growth. Here, some plots were completely recovered after three years. Despite lower rates of advance from the edge, colonization of Hypnum jutlandicum was faster than and of Dicranum scoparium as fast than that of Pleurozium schreberi because of a larger diaspore bank. Thus, each bryophyte species was characterized by a different habitat occupation strategy. The different clonal colonization strategies account for the high competitive capacity and regeneration potential of the investigated bryophyte species in pine forests despite of the lack of generative reproduction. Experimental disturbance resulted in a temporary increase of bryophyte diversity, because short-lived Colonists with a low competitive capacity colonized the gaps, before they will be overgrown by the dominant Perennials}, language = {en} } @article{KroeningSchellerWollenbergeretal.2004, author = {Kr{\"o}ning, Steffen and Scheller, Frieder W. and Wollenberger, Ursula and Lisdat, Fred}, title = {Myoglobin-Clay Electrode for Nitric Oxide (NO) Detection in Solution}, year = {2004}, language = {en} } @article{GehmlichGeierOsterzieletal.2004, author = {Gehmlich, Katja and Geier, C. and Osterziel, Karl Joseph and F{\"u}rst, Dieter Oswald}, title = {Mutant muscle LIM protein is associated with hypertrophic cardiomyopathy and exhibits altered binding properties in the system MLP - N-RAP - alpha-actinin}, issn = {0171-9335}, year = {2004}, language = {en} } @book{BurkartDierschkeHoelzeletal.2004, author = {Burkart, Michael and Dierschke, Hartmut and H{\"o}lzel, Norbert and Nowak, Bernd and Fartmann, Thomas}, title = {Molinio-Arrhenatheretea = Kulturgrasland und verwandte Vegetationstypen. Teil 2: Molinietalia}, series = {Synopsis der Pflanzengesellschaften Deutschlands}, volume = {9}, journal = {Synopsis der Pflanzengesellschaften Deutschlands}, publisher = {Selbstverl. der Floristisch-Soziologischen Arbeitsgemeinschaft}, address = {G{\"o}ttingen}, issn = {1433-8440}, pages = {103 S.}, year = {2004}, language = {de} } @phdthesis{Helaly2004, author = {Helaly, Alaa El-din A.}, title = {Molecular studies on plants to enhance their stress tolerance}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-2427}, school = {Universit{\"a}t Potsdam}, year = {2004}, abstract = {Environmental stresses such as drought, high salt and low temperature affect plant growth and decrease crop productivity extremely. It is important to improve stress tolerance of the crop plant to increase crop yield under stress conditions. The Arabidopsis thaliana salt tolerance 1 gene (AtSTO1) was originally identified by Lippuner et al., (1996). In this study around 27 members of STO-like proteins were identified in Arabidopsis thaliana, rice and other plant species. The STO proteins have two consensus motifs (CCADEAAL and FCV(L)EDRA). The STO family members can be regarded as a distinct class of C2C2 proteins considering their low sequence similarity to other GATA like proteins and poor conservation in the C-terminus. AtSTO1 was found to be induced by salt, cold and drought in leaves and roots of 4-week-old Arabidopsis thaliana wild-type plants. The expression of AtSTO1 under salt and cold stress was more pronounced in roots than in leaves. The data provided here revealed that the AtSTO1 protein is localized in the nucleus. The observation that AtSTO1 localizes in the nucleus is consistent with its proposed function as a transcription factor. AtSTO1-dependent phenotypes were observed when plant were grown at 50 mM NaCl on agar plates. Leaves of AtSTO1 overexpression lines were bigger with dark green coloration, whereas stunted growth and yellowish leaves were observed in wild-type and RNAi plants. Also, the AtSTO1 overexpression plants when exposed to long-term cold stress had a red leaf coloration which was much stronger than in wild-type and RNAi lines. Growth of AtSTO1 overexpression lines in long term under salt and cold stress was always associated with long roots which was more pronounced than in wild-type and RNAi lines. Proline accumulation increased more strongly in leaves and roots of AtSTO1 overexpression lines than in tissues of wild-type and RNAi lines when treated with 200 mM NaCl, exposed to cold stress or when watering was prevented for one day or two weeks. Also, soluble sugar content increased to higher levels under salt, cold and drought stress in AtSTO1 overexpression lines when compared to wild-type and RNAi lines. The increase in soluble sugar content was detected in AtSTO1 overexpression lines after long-term (2 weeks) growth of plants under these stresses. Anthocyanins accumulated in leaves of AtSTO1 overexpression lines when exposed to long term salt stress (200 mM NaCl for 2 weeks) or to 4°C for 6 and 8 weeks. Also, anthocyanin content was increased in flowers of AtSTO1 overexpression plants kept at 4°C for 8 weeks. Taken together these data indicate that overexpression of AtSTO1 enhances abiotic stress toleranc via a more pronounced accumulation of compatible solutes under stress.}, language = {en} } @phdthesis{GomezMerino2004, author = {G{\´o}mez-Merino, Fernando Carlos}, title = {Molecular and physiological analyses of diacylglycerol kinases from arabidopsis thaliana (L.) Heynh.}, pages = {VI, 123 S. : Ill., graph. Darst.}, year = {2004}, language = {en} } @article{RavaoarimananaTiedemannMontagnonetal.2004, author = {Ravaoarimanana, I. B. and Tiedemann, Ralph and Montagnon, D. and Rumpler, Y.}, title = {Molecular and cytogenetic evidence for cryptic speciation within a rare endemic Malagasy lemur, the Northern Sportive Lemur (Lepilemur septentrionalis)}, issn = {1055-7903}, year = {2004}, abstract = {Evolutionary relationships of different populations of the threatened malagasy lemur Lepilemur septentrimialis were assessed by sequence analysis of mitochondrial DNA (D-loop region and partial Cyt b gene). One hundred and fifty nine samples were collected from five main different localities in the northern part of Madagascar. We applied the phylogenetic species concept based on fixed diagnostic differences to determine the status of different geographical populations. No nucleotide site diagnoses Ankarana from Andrafiamena or Analamera. However, numerous fixed differences separate Sahafary from all other populations. These results were corroborated by phylogenetic trees. As previous cytogenetic studies, our molecular data suggest that two cryptic species of Lepilemur occur in the extreme north of Madagascar. This speciation is probably caused by chromosomal rearrangements in at least one of the evolutionary lineages. Our study comprises another striking example of how molecular genetic assay can detect phylogenetic discontinuities that are not reflected in traditional morphologically based taxonomies. Our study indicates that the Sahafary population is a hitherto undescribed endangered endemic species which urgently needs conservation efforts. (C) 2003 Elsevier Inc. All rights reserved}, language = {en} } @article{JeltschTewsMoloney2004, author = {Jeltsch, Florian and Tews, J{\"o}rg and Moloney, Kirk A.}, title = {Modelling seed dispersal in a variable environment : a case study of the fleshy-fruited savanna shrub Grewia flava}, year = {2004}, abstract = {In ecology much attention has been paid towards seed dispersal of fleshy-fruited plants, however, knowledge is lacking about the Iona-term demographic consequences of variation in dispersal distance and fruit removal rate, particularly given the natural variability of the environment the organism lives in. In this study we used a spatially explicit, two-level stochastic computer model to simulate population dynamics of a fleshy-fruited shrub living in the sub-canopy of solitary savanna trees. On the landscape level we implemented three realistic scenarios of savanna landscape dynamics for a period of 500 years with equal inter-annual mean of environmental variables. The first scenario is representative of a relatively constant environment with normal variability in precipitation, constant tree density and random tree recruitment pattern. The second and third scenarios represent positive auto-correlated, cyclic patterns with alternating phases of tree cover increase and decrease corresponding with favorable and unfavorable rain phases. Our simulation experiments show that when fruit removal rate is extremely low, population persistence is enhanced under relatively constant rain conditions, while alternating rain phases of the cyclic scenarios lead to a significant population decrease. This result confirms previous findings that periodically fluctuating environments may increase local extinction risk. However, when dispersal distance is a limiting factor (whilst removal rate was sufficiently high), tree clumps typically forming in wet phases of both cyclic scenarios compensated for the negative effect of low dispersal distances, while the constant scenario with random tree pattern and larger inter-tree distances resulted in a significant population decline. (C) 2003 Elsevier B.V. All rights reserved}, language = {en} } @phdthesis{Venevskaia2004, author = {Venevskaia, Irina}, title = {Modeling of vegetation diversity and a national conservation planning: example of Russia}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0001863}, school = {Universit{\"a}t Potsdam}, year = {2004}, abstract = {Die {\"u}bergreifende Zielsetzung meiner Studie ist eine Ausarbeitung quantitativer Methoden zur nationalen nationale Schutzplanung in {\"U}bereinstimmung mit dem internationalen Ansatz. Diese Zielsetzung erfordert eine L{\"o}sung der folgenden Probleme: 1) Wie l{\"a}sst sich Vegetationsvielfalt in grober Aufl{\"o}sung auf Basis abiotischen Faktoren einsch{\"a}tzen? 2) Wie ist der Ansatz 'globaler Hotspots' f{\"u}r die Eingrenzung nationaler Biodiversit{\"a}ts-Hotspots zu {\"u}bernehmen? 3) Wie erfolgt die Auswahl von quantitativen Schutzzielen unter Einbezug der Unterschiede nationaler Hotspots bei Umweltbedingungen und durch den Menschen Bedrohung? 4) Wie sieht der Entwurf eines großfl{\"a}chigen nationalen Naturschutzkonzepts aus, das die hierarchische Natur der Artenvielfalt reflektiert? Die Fallstudie f{\"u}r nationale Naturschutzplanung ist Russland. Die nachfolgenden theoretischen Schl{\"u}sse wurden gezogen: · Großr{\"a}umige Vegetationsdiversit{\"a}t ist weitgehend vorhersagbar durch klimabedingte latente W{\"a}rme f{\"u}r Verdunstung und topographische Landschaftsstruktur, beschrieben als H{\"o}hendifferenz. Das klimabasierte Modell reproduziert die beobachtete Artenanzahl von Gef{\"a}ßpflanzen f{\"u}r verschiedene Gebiete auf der Welt mit einem durchschnittlichen Fehler von 15\% · Nationale Biodiversit{\"a}ts-Hotspots k{\"o}nnen auf Grundlage biotischer oder abiotischer Daten kartographiert werden, indem als Korrektur f{\"u}r ein Land die quantitativen Kriterien f{\"u}r Planzenendemismus und Landnutzung des Ansatzes der 'globalen Hotspots' genutzt wird · Quantitative Naturschutzziele, die die Unterschiede zwischen nationalen Biodiversit{\"a}ts-Hotspots in Bezug auf Umweltbedingungen und der Bedrohung durch den Menschen miteinbeziehen, k{\"o}nnen mit nationalen Daten {\"u}ber Arten auf der Roten Liste gesetzt werden · Ein großr{\"a}umiger nationaler Naturschutzplan, der die hierarchische Natur der Artenvielfalt ber{\"u}cksichtigt, kann durch eine Kombination von abiotischer Methode im nationalen Bereich (Identifikation großr{\"a}umiger Hotspots) und biotischer Methode im regionalen Bereich (Datenanalyse der Arten auf der Roten Liste) entworfen werden}, language = {en} } @article{TiedemannPaulusScheeretal.2004, author = {Tiedemann, Ralph and Paulus, Kirsten B. and Scheer, M. and Von Kistowski, K. G. and Skirnisson, K. and Bloch, D. and Dam, M.}, title = {Mitochondrial DNA and microsatellite variation in the eider duck (Somateria mollissima) indicate stepwise postglacial colonization of Europe and limited current long-distance dispersal}, issn = {0962-1083}, year = {2004}, abstract = {To unravel the postglacial colonization history and the current intercolony dispersal in the common eider, Somateria mollissima, we analysed genetic variation at a part of the mitochondrial control region and five unlinked autosomal microsatellite loci in 175 eiders from 11 breeding colonies, covering the entire European distribution range of this species. As a result of extreme female philopatry, mitochondrial DNA differentiation is substantial both among local colonies and among distant geographical regions. Our study further corroborates the previous hypothesis of a single Pleistocene refugium for European eiders. A nested clade analysis on mitochondrial haplotypes suggests that (i) the Baltic Sea eider population is genetically closest to a presumably ancestral population and that (ii) the postglacial recolonization progressed in a stepwise fashion via the North Sea region and the Faroe Islands to Iceland. Current long-distance dispersal is limited. Differentiation among colonies is much less pronounced at microsatellite loci. The geographical pattern of this nuclear genetic variation is to a large extent explained by isolation by distance. As female dispersal is very limited, the geographical pattern of nuclear variation is probably explained by male-mediated gene flow among breeding colonies. Our study provides genetic evidence for the assumed prominent postglacial colonization route shaping the present terrestrial fauna of the North Atlantic islands Iceland and the Faroes. It suggests that this colonization had been a stepwise process originating in continental Europe. It is the first molecular study on eider duck populations covering their entire European distribution range}, language = {en} } @article{FeulnerBielfeldtZachosetal.2004, author = {Feulner, Philine g. d. and Bielfeldt, Wiebke and Zachos, F. E. and Bradvarovic, J. and Eckert, I. and Hartl, G. B.}, title = {Mitochondrial DNA and microsatellite analyses of the genetic status of the presumed subspecies Cervus elaphus montanus (Carpathian red deer)}, issn = {0018-067X}, year = {2004}, abstract = {The possibly distinct Carpathian red deer was compared genetically to other European populations. We screened 120 red deer specimens from Serbia, the Romanian lowland and the Romanian Carpathians for genetic variability using 582 bp of the mitochondrial control region and nine polymorphic nuclear microsatellite loci. The study aimed at a population genetic characterization of the Carpathian red deer, which are often treated as a distinct subspecies (Cervus elaphus montanus). The genetic integrity of the Carpathian populations was confirmed through the haplotype distribution, private alleles and genetic distances. The Carpathian red deer are thus identified as one of the few remaining natural populations of this species, deserving special attention among game and conservation biologists. The history of the populations studied, in particular the introduction of Carpathian red deer into Romanian lowland areas in the 20th century, was reflected by the genetic data}, language = {en} } @article{WiegandJeltschWard2004, author = {Wiegand, K. and Jeltsch, Florian and Ward, D.}, title = {Minimum recruitment frequency in plants with episodic recruitment}, year = {2004}, abstract = {There is concern about the lack of recruitment of Acacia trees in the Negev desert of Israel. We have developed three models to estimate the frequency of recruitment necessary for long-term population survival (i.e. positive average population growth for 1,000 years and <10\% probability of extinction). Two models assume purely episodic recruitment based on the general notion that recruitment in and environments is highly episodic. They differ in that the deterministic model investigates average dynamics while the stochastic model does not. Studies indicating that recruitment episodes in and environments have been overemphasized motivated the development of the third model. This semi-stochastic model simulates a mixture of continuous and episodic recruitment. Model analysis was done analytically for the deterministic model and via running model simulations for the stochastic and semi-stochastic models. The deterministic and stochastic models predict that, on average, 2.2 and 3.7 recruitment events per century, respectively, are necessary to sustain the population. According to the semi-stochastic model, 1.6 large recruitment events per century and an annual probability of 50\% that a small recruitment event occurs are needed. A consequence of purely episodic recruitment is that all recruitment episodes produce extremely large numbers of recruits (i.e. at odds with field observations), an evaluation that holds even when considering that rare events must be large. Thus, the semi- stochastic model appears to be the most realistic model. Comparing the prediction of the semi-stochastic model to field observations in the Negev desert shows that the absence of observations of extremely large recruitment events is no reason for concern. However, the almost complete absence of small recruitment events is a serious reason for concern. The lack of recruitment may be due to decreased densities of large mammalian herbivores and might be further exacerbated by possible changes in climate, both in terms of average precipitation and the temporal distribution of rain}, language = {en} } @misc{Heinken2004, author = {Heinken, Thilo}, title = {Migration of an annual myrmecochore}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-5865}, year = {2004}, abstract = {A seed sowing experiment was conducted in a mixed secondary woodland on acidic soils in NE Germany with Melampyrum pratense, an annual ant-dispersed forest herb which lacks a natural population in the study area, but is abundant in similar habitats. Each set of 300 seeds was sown within one square metre at three sites in 1997, and the development of the populations was recorded from 1998 onward. Additionally, seed fall patterns were studied in a natural population by means of adhesive cardboard. All trials resulted in the recruitment of populations, which survived and increased in both individual number and area, up to the year 2001. Thus, local distribution of Melampyrum pratense is dispersallimited. Total individual number increased from 105 to 3,390, and total population area from 2.07 to 109.04 m². Migration occurred in all directions. Mean migration rate was 0.91 m per year, and the highest migration rate was 6.48 m. No individual was recorded beyond 7.63 m from the centres of the sawn squares after three years, suggesting exclusive short-distance dispersal. As primary dispersal enables only distances of up to 0.25 m, ants are presumed to be the main dispersal vectors. Despite differences in individual number and colonization patterns, migration rates did not differ significantly between the populations, but were significantly higher in 2001 due to an increased population size. Colonization patterns were characterized by a rapid, negative exponential decrease of population density with increasing distance from the sown plot, suggesting a colonization by establishment of more or less isolated outposts of individuals and a subsequent gradual infill of the gaps between. My results resemble myrmecochorous dispersal distances in temperate woodlands, and migration rates and patterns across ecotones from ancient to recent deciduous forests. They may function as a colonization model of Melampyrum pratense after accidental long-distance dispersal.}, language = {en} } @article{SegertZierke2004, author = {Segert, Astrid and Zierke, Irene}, title = {Methodische Grundlagen der soziologischen Bewertung von Offenland}, isbn = {3-540-22449-1}, year = {2004}, language = {de} } @article{TittelKamjunke2004, author = {Tittel, J{\"o}rg and Kamjunke, Norbert}, title = {Metabolism of dissolved organic carbon by planktonic bacteria and mixotrophic algae in lake neutralisation experiments}, year = {2004}, abstract = {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.}, language = {en} } @article{vanKleunenLenssenFischeretal.2004, author = {van Kleunen, Mark and Lenssen, J. P. M. and Fischer, Markus and de Kroon, H.}, title = {Local adaption of the clonal plant Ranunculus reptans to flooding along a small-scale gradient.}, year = {2004}, language = {en} } @misc{SchultzeLemkeLoehmannsroeben2004, author = {Schultze, Rainer H. and Lemke, Matthias and L{\"o}hmannsr{\"o}ben, Hans-Gerd}, title = {Laser-induced fluorescence (LIF) spectroscopy for the in situ analysis of petroleum product-contaminated soils}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-12271}, year = {2004}, abstract = {Contents: Introduction Experimental Techniques: The LIF demonstrator unit - The LIF demonstrator unit - The mobile LIF spectrometer OPTIMOS - Investigated petroleum products and soil samples Results and Discussion: Photophysical properties of the petroleum products LIF spectroscopic investigations of oil-spiked samples LIF spectroscopic investigations of real-world soils Conclusions}, language = {en} } @article{KernKnoesche2004, author = {Kern, J{\"u}rgen and Kn{\"o}sche, R{\"u}diger}, title = {Landwirtschaft und Gew{\"a}sserschutz im Land Brandenburg}, isbn = {3-89998-033-6}, year = {2004}, language = {de} } @article{SchefflerKetelhutMorgenstern2004, author = {Scheffler, Christiane and Ketelhut, Kerstin and Morgenstern, Ulrike}, title = {K{\"o}rperliche und motorische Entwicklung von Kindern unterschiedlicher sozialer Herkunft.}, year = {2004}, language = {de} } @article{Baumann2004, author = {Baumann, Otto}, title = {Konventionelle Fluoreszenzmikroskopie : Theorie und Anwendungsm{\"o}glichkeiten}, year = {2004}, language = {de} } @article{KneisKnoescheBronstert2004, author = {Kneis, David and Kn{\"o}sche, R{\"u}diger and Bronstert, Axel}, title = {Ist ein Netto-N{\"a}hrstoffexport aus Flussgew{\"a}ssersedimenten eine realistische Option zur Trophiesenkung?}, isbn = {3-937758-18-6}, year = {2004}, language = {de} } @article{SauerNeukirchenRahimietal.2004, author = {Sauer, Heinrich and Neukirchen, W. and Rahimi, G. and Gr{\"u}nbeck, Frank and Hescheler, J{\"u}rgen and Wartenberg, Maria}, title = {Involvement of reactive oxygen species in cardiotropin-1 (CT-1)-induced cell proliferation of cardiomyocytes differentiated from murine embryonic stem cells}, year = {2004}, language = {en} } @article{VerginFreierGzik2004, author = {Vergin, Anika and Freier, B. and Gzik, Axel}, title = {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.)}, year = {2004}, language = {en} } @article{PiontekWinklerBaletal.2004, author = {Piontek, J. and Winkler, Lars and Bal, M. S. and Lassowski, Birgit and Mueller, Sandra L. and Gast, Klaus and Blasig, Ingolf E.}, title = {Investigating of homophilic interactions of the tight junction proteins occludin and claudin-5}, year = {2004}, language = {en} } @article{SchenkMatyssekMicheel2004, author = {Schenk, J{\"o}rg A. and Matyssek, Franziska and Micheel, Burkhard}, title = {Interleukin 4 increases the antibody response against Rubisco in mice}, year = {2004}, abstract = {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.}, language = {en} } @phdthesis{Steinhauser2004, author = {Steinhauser, Dirk}, title = {Inferring hypotheses from complex profile data - by means of CSB.DB, a comprehensive systems-biology database}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-2467}, school = {Universit{\"a}t Potsdam}, year = {2004}, abstract = {The past decades are characterized by various efforts to provide complete sequence information of genomes regarding various organisms. The availability of full genome data triggered the development of multiplex high-throughput assays allowing simultaneous measurement of transcripts, proteins and metabolites. With genome information and profiling technologies now in hand a highly parallel experimental biology is offering opportunities to explore and discover novel principles governing biological systems. Understanding biological complexity through modelling cellular systems represents the driving force which today allows shifting from a component-centric focus to integrative and systems level investigations. The emerging field of systems biology integrates discovery and hypothesis-driven science to provide comprehensive knowledge via computational models of biological systems. Within the context of evolving systems biology, investigations were made in large-scale computational analyses on transcript co-response data through selected prokaryotic and plant model organisms. CSB.DB - a comprehensive systems-biology database - (http://csbdb.mpimp-golm.mpg.de/) was initiated to provide public and open access to the results of biostatistical analyses in conjunction with additional biological knowledge. The database tool CSB.DB enables potential users to infer hypothesis about functional interrelation of genes of interest and may serve as future basis for more sophisticated means of elucidating gene function. The co-response concept and the CSB.DB database tool were successfully applied to predict operons in Escherichia coli by using the chromosomal distance and transcriptional co-responses. Moreover, examples were shown which indicate that transcriptional co-response analysis allows identification of differential promoter activities under different experimental conditions. The co-response concept was successfully transferred to complex organisms with the focus on the eukaryotic plant model organism Arabidopsis thaliana. The investigations made enabled the discovery of novel genes regarding particular physiological processes and beyond, allowed annotation of gene functions which cannot be accessed by sequence homology. GMD - the Golm Metabolome Database - was initiated and implemented in CSB.DB to integrated metabolite information and metabolite profiles. This novel module will allow addressing complex biological questions towards transcriptional interrelation and extent the recent systems level quest towards phenotyping.}, subject = {Datenbank}, language = {en} } @article{HeschelerWartenbergWenzeletal.2004, author = {Hescheler, J{\"u}rgen and Wartenberg, Maria and Wenzel, D. and Roell, B. K. and Lu, Z. and Xia, Y. and Donmez, F. and Ling, Frederike C. and Acker, Helmut and Kolossov, E. and Kazemi, S. and Sasse, P. and Raible, A. and Bohlen, H. and Fleischmann, B. K.}, title = {Implication of therapeutic cloning for organ transplantation}, year = {2004}, language = {en} } @phdthesis{Kreuzer2004, author = {Kreuzer, Oliver Johannes}, title = {Immunozytochemische Analyse des Internalisierungswegs des Somatostatin-Rezeptors 3 der Ratte und Untersuchungen zur Prozessierung des internalisiertem Peptid Liganden f{\"u}r die Rezeptor-Subtypen 1 und 3 der Ratte}, address = {Potsdam}, pages = {133 S. : Ill., graph. Darst.}, year = {2004}, language = {de} } @phdthesis{Ringleb2004, author = {Ringleb, Jennifer}, title = {Identifikation antigener Determinanten des ZPB2 Proteins der Hauskatze und Charakterisierung ihrer kontrazeptiven und immunogenen Eigenschaften}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0001901}, school = {Universit{\"a}t Potsdam}, year = {2004}, abstract = {Die immunologische Kontrazeption mittels Zona pellucida (ZP) Proteinen gilt als vielversprechender Ansatz f{\"u}r die Reproduktionskontrolle verwilderter Haus- und Wildtierbest{\"a}nde. Da die Applikation von nativer ZP mit Nebenwirkungen verbunden ist, wird die Verwendung einzelner ZP Peptide als Bestandteil kontrazeptiver Vakzine als besonders aussichtsreich erachtet. Das Prinzip dieser nebenwirkungsfreien ZP Immunisierung ist die gezielte Trennung der Entz{\"u}ndungsreaktionen ausl{\"o}senden T-Zell-Epitope der ZP von den kontrazeptiv wirkenden B-Zell-Epitopen. Niedermolekulare synthetische oder rekombinante Peptide allein sind gering immunogen und k{\"o}nnen somit keine ausreichende Immunantwort induzieren. Die Verwendung von Peptiden f{\"u}r die immunologische Kontrazeption erfordert daher ein \„Vakzin-Design\“, d. h. die gezielte Kombination der Peptide mit immunstimulierenden Substanzen (Liposomen, Carrierproteinen, Adjuvantien). Zielstellung der vorliegenden Arbeit war die Untersuchung des Potentials synthetischer Peptide f{\"u}r die Immunokontrazeption von verwilderten Hauskatzen (Felis catus). Dazu wurden zun{\"a}chst relevante B-Zell-Epitope des felinen Zona pellucida Proteins, ZPB2, identifiziert und synthetisiert. Zwei der synthetischen Peptide (P3, P6) wurden zur Herstellung von Antik{\"o}rpern an BSA konjugiert und zusammen mit Freundschem Adjuvans in Ratten verimpft. Die kontrazeptive Relevanz beider Peptide sowie der Ratten Anti-Peptid Antiseren wurde im in vitro Befruchtungssystem der Hauskatze gepr{\"u}ft. Zur Untersuchung der Immunogenit{\"a}t der Peptide in der Zielspezies Hauskatze erfolgte die Entwicklung von Vakzin-Prototypen f{\"u}r die einmalige Applikation. Neben der Eruierung der St{\"a}rke und Dauer der Immunantwort wurde durch Verpaarung der Tiere auch das kontrazeptive Potential in vivo abgesch{\"a}tzt.}, language = {de} } @phdthesis{Lemke2004, author = {Lemke, Britt}, title = {Identification of Epo-independent red cell progenitors : the E-cad+ progenitors}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0001432}, school = {Universit{\"a}t Potsdam}, year = {2004}, abstract = {Erythrozyten z{\"a}hlen zu den am h{\"a}ufigsten vorkommenden terminal differenzierten Zelltypen des menschlichen K{\"o}rpers. Durchschnittlich werden t{\"a}glich ca. 2 x 1011 von ihnen im K{\"o}rper eines erwachsenen Menschen produziert. Die reifen Erythrozyten entstehen aus multipotenten h{\"a}matopoetischen Stammzellen, die {\"u}ber Stadien von erythroiden Vorl{\"a}uferzellen, erst den sogenannten burst forming units-erythroid (BFU-E) und sp{\"a}ter den colony forming units-erythroid (CFU-E), zu kernlosen h{\"a}moglobinisierten Zellen differenzieren. F{\"u}r die Untersuchung der molekularen Mechanismen der humanen Erythropoese ist die effektive in vitro Amplifizierung einer weitgehend homogenen Population der Vorl{\"a}uferzellen der einzelnen Entwicklungsstadien notwendig. Den Wachstumsfaktoren stem cell factor (SCF) und Erythropoietin (Epo) f{\"a}llt dabei eine entscheidende Rolle zu. Unter ihrem synergistischen Einfluß lassen sich Epo-abh{\"a}ngige Zellpopulationen, die sich aus BFU-E und CFU-E Typ Zellen zusammensetzen, ausreichend amplifizieren (Panzenb{\"o}ck et al., 1998). Freyssinier et al., 1999 beschrieb erstmals die Isolierung einer Epo-unabh{\"a}ngigen Population von Vorl{\"a}uferzellen (CD36+ Vorl{\"a}uferzellen), die ebenfalls erythroide Eigenschaften aufweisen. Ziel dieser Arbeit war die Isolierung und Charakterisierung von Epo-unabh{\"a}ngigen Vorl{\"a}uferzellen, die eine fr{\"u}he erythroide und m{\"o}glichst homogene Vorl{\"a}uferzellpopulation darstellen und m{\"o}glicherweise ein h{\"o}heres Proliferationspotential aufweisen. F{\"u}r die Identifizierung der Epo-unabh{\"a}ngigen Vorl{\"a}uferzellen, wurden CD34+ Zellen aus Nabelschnurblut aufgereinigt und unter serumfreien Kulturbedingungen und unter Zusatz der Wachstumsfaktoren SCF, Interleukin 3 (IL-3) und eines Fusionsproteins aus IL-6 und l{\"o}slichem IL-6 Rezeptor (hyper-IL-6) {\"u}ber einen Zeitraum von 8 Tagen kultiviert. Anschließend wurde eine Population von E-cadherin positiven (E-cad+) Zellen {\"u}ber immunomagnetische Selektion isoliert. Diese neu gewonnenen Epo-unabh{\"a}ngigen E-cad+ Vorl{\"a}uferzellen wurden hinsichtlich ihres proliferativen Potentials und ihrer Differenzierungseigenschaften mit SCF/Epo-Vorl{\"a}uferzellen und CD36+ Vorl{\"a}uferzellen verglichen. Von allen drei Zelltypen wurden des weiteren detailierte molekulargenetische Analysen mittels DNA microarray Technologie durchgef{\"u}hrt und die resultierenden Genexpressionsmuster miteinander verglichen. Die Ergebnisse zeigen, dass die E-cad+ Vorl{\"a}uferzellen eine fr{\"u}he, weitgehend homogene Epo-unabh{\"a}ngige Population vom BFU-E Typ darstellen und durch entsprechende {\"A}nderungen der Kulturbedingungen zu einer in vitro Differenzierung angeregt werden k{\"o}nnen. Die E-cad+ Vorl{\"a}uferzellen sind hinsichtlich ihres proliferativen Potentials, ihrer Reaktion auf verschiedene Wachstumsfaktoren, der Expression spezifischer Oberfl{\"a}chenmolek{\"u}le und ihrer Genexpressionsmuster mit SCF/Epo-Vorl{\"a}uferzellen und CD36+ Vorl{\"a}uferzellen vergleichbar. Aufgrund der Identifizierung unterschiedlich exprimierter Gene zwischen den Epo-unabh{\"a}ngigen E-cad+ und den Epo-abh{\"a}ngigen SCF/Epo Vorl{\"a}uferzellen konnten Kanditatengene wie Galectin-3, Cyclin D1, der Anti-M{\"u}llerian Hormonrezeptor, Prostata-Differenzierungsfaktor und insulin-like growth factor binding protein 4 identifiziert werden, die als potentielle Regulatoren der Erythropoese in Betracht kommen k{\"o}nnten. Es konnte weiterhin gezeigt werden, dass CD36+ Vorl{\"a}uferzellen, die aus der selben Zellpopulation wie die E-cad+ Vorl{\"a}uferzellen immunomagnetisch selektioniert wurden, eine heterogene Population darstellen, die sowohl E-cadherin positive als auch negative Zellen enth{\"a}lt. Die Analyse der Genexpressionsmuster zeigte, dass in den CD36+ Vorl{\"a}uferzellen zwar auch die Expression erythroid-spezifischen Gene nachgewiesen werden kann, hier aber im Gegensatz zu den E-cad+ Vorl{\"a}uferzellen auch f{\"u}r Megakaryozyten spezifische Gene stark exprimiert sind. Die Ergebnisse dieser Arbeit tragen zu einem neuen Modell der in vivo Abl{\"a}ufe der Entwicklung roter Blutzellen bei und werden der weiteren Untersuchung der molekularen Mechanismen der Erythropoese dienen.}, language = {en} } @phdthesis{Draeger2004, author = {Dr{\"a}ger, D{\"o}rthe B.}, title = {Identification and Characterisation of Genes Involved in Metal Tolerance and Hyperaccumulation in Arabidopsis halleri}, pages = {119 S. : graph. Darst.}, year = {2004}, language = {en} } @article{LettauGajovicEichelmannKwaketal.2004, author = {Lettau, Kristian and Gajovic-Eichelmann, N. and Kwak, Young-Keun and Scheller, Frieder W. and Warsinke, Axel}, title = {Hydroxylasen und katalytische Polymere f{\"u}r Biochips}, year = {2004}, language = {de} } @phdthesis{Scheich2004, author = {Scheich, Christoph}, title = {High-throughput evaluation of protein folding conditions and expression constructs for structural genomics}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0001552}, school = {Universit{\"a}t Potsdam}, year = {2004}, abstract = {Das E. coli Expressionssystem ist das am h{\"a}ufigsten angewandte hinsichtlich der rekombinante Proteinexpression f{\"u}r strukturelle und funktionelle Analysen aufgrund der hohen erzielten Ausbeuten und der einfachen Handhabbarkeit. Allerdings ist insbesondere die Expression eukaryotischer Proteine in E. coli problematisch, z.B. wenn das Protein nicht korrekt gefaltet ist und in unl{\"o}slichen Inclusion Bodies anf{\"a}llt. In manchen F{\"a}llen ist die Analyse von Deletionskonstrukten oder einzelnen Proteindom{\"a}nen der Untersuchung des Voll{\"a}ngeproteins vorzuziehen. Dies umfasst die Herstellung eines Satzes von Expressionskonstrukten, welche charakterisiert werden m{\"u}ssen. In dieser Arbeit werden Methoden optimiert und evaluiert f{\"u}r die in vitro-Faltung von Inclusion Body-Proteinen sowie die Entwicklung einer Hochdurchsatz-Charakterisierung von Expressionskonstrukten. Die {\"U}berf{\"u}hrung von Inclusion Body-Proteinen in den nativen Zustand beinhaltet zwei Schritte: (a) Aufl{\"o}sen mit einen chaotropen Reagenz oder starkem ionischen Detergenz und (b) Faltung des Proteins durch Beseitigung des Chaotrops begleitet von dem Transfer in einen geeigneten Puffer. Die Ausbeute an nativ gefaltetem Protein ist oft stark eingeschr{\"a}nkt aufgrund von Aggregation und Fehlfaltung; sie kann allerdings durch die Zugabe bestimmter Additive zum Faltungspuffer erh{\"o}ht werden. Solche Additive m{\"u}ssen empirisch identifiziert werden. In dieser Arbeit wurde eine Testprozedur f{\"u}r Faltungsbedingungen entwickelt. Zur Reduzierung der m{\"o}glichen Kombinationen der getesteten Additive wurden sowohl empirische Beobachtungen aus der Literatur als auch bekannte Eigenschaften der Additive ber{\"u}cksichtigt. Zur Verminderung der eingesetzten Proteinmenge und des Arbeitsaufwandes wurde der Test automatisiert und miniaturisiert mittels eines Pipettierroboters. 20 Bedingungen zum schnellen Verd{\"u}nnen von denaturierten Proteinen werden hierbei getestet und zwei Bedingungen zur Faltung von Proteinen mit dem Detergenz/Cyclodextrin Protein-Faltungssystem von Rozema et al. (1996). 100 \&\#181;g Protein werden pro Bedingung eingesetzt. Zus{\"a}tzlich werden acht Bedingungen f{\"u}r die Faltung von His-Tag-Fusionsproteinen (ca. 200 \&\#181;g), welche an eine Metallchelat-Matrix immobilisiert sind, getestet. Die Testprozedur wurde erfolgreich angewendet zur Faltung eines humanen Proteins, der p22 Untereinheit von Dynactin, welche in E. coli in Inclusion Bodies exprimiert wird. So wie es sich bei vielen Proteinen darstellt, war auch f{\"u}r p22 Dynactin kein biologischer Nachweistest vorhanden, um den Erfolg des Faltungsexperimentes zu messen. Die L{\"o}slichkeit des Proteins kann nicht als eindeutiges Kriterium dienen, da neben nativ gefaltetem Protein, l{\"o}sliche fehlgefaltete Spezies und Mikroaggregate auftreten k{\"o}nnen. Diese Arbeit evaluiert Methoden zur Detektion kleiner Mengen nativen Proteins nach dem automatisierten Faltungstest. Bevor p22 Dynactin gefaltet wurde, wurden zwei Modellenzyme zur Evaluierung eingesetzt, bovine Carboanhydrase II (CAB) und Malat Dehydrogenase aus Schweineherz-Mitochondrien. Die wiedererlangte Aktivit{\"a}t nach der R{\"u}ckfaltung wurde korreliert mit verschiedenen biophysikalischen Methoden. Bindungsstudien mit 8-Anilino-1-Naphtalenesulfons{\"a}ure ergaben keine brauchbaren Informationen bei der R{\"u}ckfaltung von CAB aufgrund der zu geringen Sensitivit{\"a}t und da fehlgefaltete Proteine nicht eindeutig von nativem Protein unterschieden werden konnten. Tryptophan Fluoreszenzspektren der r{\"u}ckgefalteten CAB wurden zur Einsch{\"a}tzung des Erfolges der R{\"u}ckfaltung angewandt. Die Verschiebung des Intensit{\"a}tsmaximum zu einer niedrigeren Wellenl{\"a}nge im Vergleich zum denaturiert entfalteten Protein sowie die Fluoreszenzintensit{\"a}t korrelierten mit der wiedererlangten enzymatischen Aktivit{\"a}t. F{\"u}r beide Modellenzyme war analytische hydrophobe Interaktionschromatographie (HIC) brauchbar zur Identifizierung r{\"u}ckgefalteter Proben mit aktivem Enzym. Kompakt gefaltetes, aktives Enzym eluierte in einem distinkten Peak im abnehmenden Ammoniumsulfat-Gradienten. Das Detektionslimit f{\"u}r analytische HIC lag bei 5 \&\#181;g. Im Falle von CAB konnte gezeigt werden, dass Tryptophan-Fluoreszenz-Spektroskopie und analytische HIC in Kombination geeignet sind um Falsch-Positive oder Falsch-Negative, welche mit einem der Monitore erhalten wurden, auszuschließen. Diese beiden Methoden waren ebenfalls geeignet zur Identifizierung der Faltungsbedingungen von p22 Dynactin. Tryptophan-Fluoreszenz-Spektroskopie kann jedoch zu Falsch-Positiven f{\"u}hren, da in machen F{\"a}llen Spektren von l{\"o}slichen Mikroaggregaten kaum unterscheidbar sind von Spektren des nativ gefalteten Proteins. Dies zusammenfassend wurde eine schnelle und zuverl{\"a}ssige Testprozedur entwickelt, um Inclusion Body-Proteine einer strukturellen und funktionellen Analyse zug{\"a}nglich zu machen. In einem separaten Projekt wurden 88 verschiedene E. coli-Expressionskonstrukte f{\"u}r 17 humane Proteindom{\"a}nen, welche durch Sequenzanalyse identifiziert wurden, mit einer Hochdurchsatzreinigung und \–faltungsanalytik untersucht, um f{\"u}r die Strukturanalyse geeignete Kandidaten zu erhalten. Nach Expression in einem Milliliter im 96er Mikrotiterplattenformat und automatisierter Proteinreinigung wurden l{\"o}slich exprimierte Proteindom{\"a}nen direkt analysiert mittels 1D \&\#185;H-NMR Spektroskopie. Hierbei zeigte sich, dass insbesondere isolierte Methylgruppen-Signale unter 0.5 ppm sensitive und zuverl{\"a}ssige Sonden sind f{\"u}r gefaltetes Protein. Zus{\"a}tzlich zeigte sich, dass \– {\"a}hnlich zur Evaluierung des Faltungstests \– analytische HIC effizient eingesetzt werden kann zur Identifizierung von Konstrukten, welche kompakt gefaltetes Protein ergeben. Sechs Konstrukte, welche zwei Dom{\"a}nen repr{\"a}sentieren, konnten schnell als tauglich f{\"u}r die Strukturanalyse gefunden werden. Die Struktur einer dieser Dom{\"a}nen wurde k{\"u}rzlich von Mitarbeitern gel{\"o}st, die andere Struktur wurde im Laufe dieses Projektes von einer anderen Gruppe ver{\"o}ffentlicht.}, language = {en} } @article{RoskeSunnaPfeiletal.2004, author = {Roske, Y. and Sunna, A. and Pfeil, Wolfgang and Heinemann, Udo}, title = {High-resolution crystal structures of Caldiceflulosiruptor strain Rt8B.4 carbohydrate-binding module CBM27-1 and its complex with mannohexaose}, issn = {0022-2836}, year = {2004}, abstract = {Carbohydrate-binding modules (CBMs) are the most common non-catalytic modules associated with enzymes active in plant cell-wall hydrolysis. Despite the large number of putative CBMs being identified by amino acid sequence alignments, only few representatives have been experimentally shown to have a carbohydrate-binding function. Caldicellulosiruptor strain Rt8B.4 Man26 is a thermostable modular glycoside hydrolase beta-mannanase which contains two non-catalytic modules in tandem at its N terminus. These modules were recently shown to function primarily as beta- mannan-binding modules and have accordingly been classified as members of a novel family of CBMs, family 27. The N- terminal CBM27 (CsCBM27-1) of Man26 from Caldicellulosiruptor Rt8B.4 displays high-binding affinity towards mannohexaose with a K-a of 1 x 10(7) M-1. Accordingly, the high-resolution crystal structures of CsCBM27-1 native and its mannohexaose complex were solved at 1.55 Angstrom and 1.06 Angstrom resolution, respectively. In the crystal, CsCBM27-1 shows the typical beta-sandwich jellyroll fold observed in other CBMs with a single metal ion bound, which was identified as calcium. The crystal structures reveal that the overall fold of CsCBM27-1 remains virtually unchanged upon sugar binding and that binding is mediated by three solvent-exposed tryptophan residues and few direct hydrogen bonds. Based on binding affinity and thermal unfolding experiments this structural calcium is shown to play a role in the thermal stability of CsCBM27-1 at high temperatures. The higher binding affinity of CsCBM27-1 to mannooligosaccharides when compared to other members of CBM family 27 might be explained by the different orientation of the residues forming the "aromatic platform" and by differences in the length of loops. Finally, evidence is presented, on the basis of fold similarities and the retention of the position of conserved motifs and a calcium ion, for the consolidation of related CBM families into a superfamily of CBMs. (C) 2004 Elsevier Ltd. All rights reserved}, language = {en} } @article{MeyerToerjekBecheretal.2004, author = {Meyer, Rhonda C. and T{\"o}rj{\´e}k, Otto and Becher, Monika and Altmann, Thomas}, title = {Heterosis of biomass production in Arabidopsis : Establishment during early development}, year = {2004}, abstract = {Heterosis has been widely used in agriculture to increase yield and to broaden adaptability of hybrid varieties and is applied to an increasing number of crop species. We performed a systematic survey of the extent and degree of heterosis for dry biomass in 63 Arabidopsis accessions crossed to three reference lines (Col-0, C24, and Nd). We detected a high heritability (69\%) for biomass production in Arabidopsis. Among the 169 crosses analyzed, 29 exhibited significant mid-parent-heterosis for shoot biomass. Furthermore, we analyzed two divergent accessions, C24 and Col-0, the F-1 hybrids of which were shown to exhibit hybrid vigor, in more detail. In the combination Col-0/C24, heterosis for biomass was enhanced at higher light intensities; we found 51\% to 66\% mid-parent-heterosis at low and intermediate light intensities (60 and 120 mumol m(-2) s(-1)), and 161\% at high light intensity (240 mumol m(-2) s(-1)). While at the low and intermediate light intensities relative growth rates of the hybrids were higher only in the early developmental phase (0-15 d after sowing [DAS]), at high light intensity the hybrids showed increased relative growth rates over the entire vegetative phase (until 25 DAS). An important finding was the early onset of heterosis for biomass; in the cross Col-0/C24, differences between parental and hybrid lines in leaf size and dry shoot mass could be detected as early as 10 DAS. The widespread occurrence of heterosis in the model plant Arabidopsis opens the possibility to investigate the genetic basis of this phenomenon using the tools of genetical genomics}, language = {en} } @article{RohdeHinchaHeyer2004, author = {Rohde, P. and Hincha, Dirk K. and Heyer, Arnd G.}, title = {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}, issn = {0960-7412}, year = {2004}, language = {en} } @article{AndersMrzljakWallschlaegeretal.2004, author = {Anders, Kenneth and Mrzljak, Jadranka and Wallschl{\"a}ger, Hans-Dieter and Wiegleb, Gerhard}, title = {Handbuch Offenlandmanagement am Beispiel ehemaliger und in Nutzung befindlicher Truppen{\"u}bungspl{\"a}tze}, publisher = {Springer}, address = {Berlin}, isbn = {3-540-22449-1}, pages = {320 S.}, year = {2004}, language = {de} } @article{Illner2004, author = {Illner, Regine}, title = {Gruppenpuzzle im Hochschulseminar : selbst erfahren, wie kooperatives lernen funktioniert}, series = {Journal f{\"u}r LehrerInnenbildung. - 4 (2004), 3, S. 67 - 71}, journal = {Journal f{\"u}r LehrerInnenbildung. - 4 (2004), 3, S. 67 - 71}, editor = {Altrichter, Herbert and Horstkemper, Marianne}, year = {2004}, language = {de} } @article{JeltschWichmannDean2004, author = {Jeltsch, Florian and Wichmann, Matthias and Dean, W. R. J.}, title = {Global change challenges the Tawny Eagle (Aquila rapax) : modelling extinction risk with respect to predicted climate and land use changes}, year = {2004}, language = {en} } @article{PilarskiNockerWagner2004, author = {Pilarski, Monika and Nocker, Ulrike and Wagner, Anja}, title = {Geografische Informationssysteme und Fernerkundung als Instrumente landschafts{\"o}kologischer Untersuchungen}, isbn = {3-540-22449-1}, year = {2004}, language = {de} }