TY - JOUR A1 - Wallschläger, Hans-Dieter A1 - Beier, Wolfgang A1 - Burkart, Michael A1 - Mrzljak, Jadranka A1 - Oehlschläger, Susanne A1 - Wanner, Manfred T1 - Ökologische Datenerfassung für Naturschutzbewertung und Monitoring im Offenland Y1 - 2004 SN - 3-540-22449-1 ER - TY - JOUR A1 - Seitz, Birgit A1 - Ristow, Michael A1 - Klemm, Gunther A1 - Rätzel, Stefan A1 - Schulze, Gerhart A1 - Hoffmann, Maik T1 - Zur Verbreitung der Wildrosen und verwilderten Kulturrosen in Berlin und Brandenburg Y1 - 2004 SN - 0724-3111 - ER - TY - JOUR A1 - Albrecht, Tanja A1 - Haebel, Sophie A1 - Koch, Anke A1 - Krause, Ulrike A1 - Eckermann, Nora A1 - Steup, Martin T1 - Yeast glycogenin (Glg2p) produced in Escherichia coli is simultaneously glucosylated at two vicinal tyrosin residues but results in a reduced bacterial glycogen accumulation N2 - 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 Y1 - 2004 ER - TY - JOUR A1 - Pacholsky, Dirk A1 - Vakeel, Padmanabhan A1 - Himmel, Mirko A1 - Lowe, T. A1 - Stradal, T. A1 - Rottner, K. A1 - Fürst, Dieter Oswald A1 - vanderVen, Peter F. M. T1 - Xin repeats define a novel actin-binding motif N2 - 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 Y1 - 2004 SN - 0021-9533 ER - TY - JOUR A1 - Kummer, Volker T1 - Vom Seidenbau in Krausnick Y1 - 2004 ER - TY - JOUR A1 - Boese, Stefan H. A1 - Gray, Michael A. A1 - Simmons, N. L. T1 - Volume and non-volume activated anion conductances and their interactions in the renal IMCD Y1 - 2004 SN - 0-387- 23299-0 ER - TY - JOUR A1 - Weithoff, Guntram T1 - Vertical niche separation of two consumers (Rotatoria) in an extreme habitat N2 - Herbivore populations are commonly restricted by resource limitation, by predation or a combination of the two. Food supplement experiments are suitable for investigating the extent of food limitation at any given time. The main part of this study was performed in an extremely acidic lake (pH 2.7) where the food web consists of only a few components and potential food sources for herbivores are restricted to two flagellates. Life table experiments proved that Chlamydomonas was a suitable food source whereas Ochromonas was an unsuitable food source. The two flagellates and the two rotifers exhibit a pronounced vertical distribution pattern. In this study, a series of food supplement experiments were performed in order to: (1) quantify and compare potential resource limitation of two primary consumers (Cephalodella hoodi and Elosa worallii, Rotatoria) over time, (2) compare their response at different temperatures, (3) evaluate the effect of having an unsuitable food source alongside a valuable one, (4) estimate the effect of predation on rotifers by Heliozoa, and (5) compare the results with those from other acidic lakes. Additionally, the spatio- temporal population dynamics of both species were observed. The field data confirmed a vertical separation of the two species with E. worallii dominating in the upper water layers, and C. hoodi in the deeper, cooler water layers. The results from the food supplement experiments in which Chlamydomonas served as the supplemented suitable food source showed that the two rotifers were food limited in the epilimnion throughout the season to different extents, with Cephalodella being more severely food limited than Elosa. The experiments at different temperatures provided evidence that Elosa had a higher optimum temperature for growth than Cephalodella. When the unsuitable food algae Ochromonas was added alongside the suitable food source Chlamydomonas, C. hoodi was unaffected but E. worallii was negatively affected. Predation of Heliozoa on rotifers was observed but the total effect on the rotifer dynamics is probably low. The comparison with other lakes showed that resource limitation also occurred in one other lake, although to a lesser extent. Overall, the vertical separation of the two rotifers could be explained by both their differential extent of resource limitation and differential response to temperature. Y1 - 2004 ER - TY - JOUR A1 - Hilson, Pierre A1 - Allemeersch, Joke A1 - Altmann, Thomas A1 - Aubourg, Sebastien A1 - Avon, Alexandra A1 - Beynon, Jim A1 - Bhalerao, Rishikesh P. A1 - Bitton, Frederique A1 - Caboche, Michel A1 - Cannoot, Bernard A1 - Chardakov, Vasil A1 - Cognet-Holliger, Cecile A1 - Colot, Vincent A1 - Crowe, Mark A1 - Darimont, Caroline A1 - Durinck, Steffen A1 - Eickhoff, Holger A1 - deLongevialle, Andeol Falcon A1 - Farmer, Edward E. A1 - Grant, Murray A1 - Kuiper, Martin T. R. A1 - Lehrach, Hans A1 - Leon, Celine A1 - Leyva, Antonio A1 - Lundeberg, Joakim A1 - Lurin, Claire A1 - Moreau, Yves T1 - Versatile gene-specific sequence tags for arabidopsis functional genomics : transcript profiling and reserve genetics applications N2 - 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 Y1 - 2004 ER - TY - JOUR A1 - Sachinidis, A. A1 - Wartenberg, Maria A1 - Sauer, Heinrich A1 - Hescheler, Jürgen T1 - Transcription factors, growth factors and signal cascades capable of priming morphogenesis of heart Y1 - 2004 SN - 1-588- 29113-8 ER - TY - JOUR A1 - Witt, Isabell A1 - Zanor, Maria Ines A1 - Müller-Röber, Bernd T1 - Transcription factor function search : how do individual factors regulate agronomical important processes in plants? (Subproject A) Y1 - 2004 SN - 3-00-011587-0 ER - TY - JOUR A1 - Krylov, Andrey V. A1 - Beissenhirtz, Moritz Karl A1 - Adamzig, Holger A1 - Scheller, Frieder W. A1 - Lisdat, Fred T1 - Thick-film electrodes for measurement of superoxide and hydrogen peroxide based on direct protein-electrode contacts N2 - 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 Y1 - 2004 ER - TY - JOUR A1 - Hanisch, Uwe-Karsten A1 - Van Rossum, Denise A1 - Xie, Yiheng A1 - Misselwitz, Rolf A1 - Auriola, Seppo A1 - Goldstein, Gundars A1 - Koistinaho, Jari A1 - Kettemann, Helmut A1 - Möller, Thomas A1 - Gast, Klaus T1 - The microglia-activating potential of thrombin : the protease is not involved in the induction of proinflammatory cytokines and chemokines N2 - 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 Y1 - 2004 ER - TY - JOUR A1 - Hanisch, Uwe-Karsten A1 - van Rossum, D. A1 - Gast, Klaus A1 - Misselwitz, Rolf A1 - Goldstein, Gundars A1 - Koistinaho, Jari A1 - Möller, Thomas T1 - The microglia-activating potential of thrombin : is the protease able to induce cyto- and chemokines? Y1 - 2004 ER - TY - JOUR A1 - Scheffler, Christiane A1 - Ketelhut, Kerstin A1 - Mohasseb, Iman A1 - Ketelhut, Reinhard G. T1 - The influence of an exercise program on body composition, motor and cardiovascular parameters in pre-school children : a longitudinal study Y1 - 2004 SN - 88-87814-25-2 ER - TY - JOUR A1 - Fettke, Jörg A1 - Eckermann, Nora A1 - Poeste, Simon A1 - Steup, Martin T1 - The glycan substrate of the cytosolic (Pho 2) phosphorylase isozyme from Pisum sativum L. : identification, linkage analysis and subcellular localization N2 - 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 Y1 - 2004 SN - 0960-7412 ER - TY - JOUR A1 - Marg, S. A1 - Walz, Bernd A1 - Blenau, Wolfgang T1 - The effects of dopamine receptor agonists and antagonists on the secretory rate of cockroach (Periplaneta americana) salivary glands N2 - 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 Y1 - 2004 SN - 0022-1910 ER - TY - JOUR A1 - Sauer, Heinrich A1 - Wartenberg, Maria A1 - Sachinidis, A. A1 - Hescheler, Jürgen T1 - The development of the cardiovascular system in embryoid bodies deriverd from embryonic stem cells Y1 - 2004 SN - 1-588- 29113-8 ER - TY - JOUR A1 - Klein, Florian A1 - Feldhahn, Niklas A1 - Harder, S. A1 - Wang, Hui A1 - Wartenberg, Maria A1 - Hofmann, W.-K. A1 - Wernet, Peter A1 - Sieber, Reiner A1 - Müschen, Markus T1 - The BCR-ABL1 kinase bypasses selection for the expressio of a pre-B cell receptor in pre-B acute lymphoblastic leukemia cells Y1 - 2004 ER - TY - JOUR A1 - Frisch, D. A1 - Santer, B. T1 - Temperature-induced responses of a permanent-pond and a temporary-pond cyclopoid copepod : a link to habitat predictability? N2 - 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 Y1 - 2004 SN - 1522-0613 ER - TY - JOUR A1 - Vaaje-Kolstad, G. A1 - Houston, Douglas R. A1 - Rao, F. V. A1 - Peter, Martin G. A1 - Synstad, Bjoenar A1 - van Aalten, Daan M. F. A1 - Eijsink, Vincent G. H. T1 - Structure of the D142N mutant of the family 18 chitinase ChiB from Serratia marcescens and its complex with allosamidin N2 - 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 Y1 - 2004 SN - 1570-9639 ER - TY - JOUR A1 - Tews, Jörg A1 - Blaum, Niels A1 - Jeltsch, Florian T1 - Structural and animal species diversity in arid and semi-arid savannas of the southern Kalahari Y1 - 2004 ER - TY - JOUR A1 - Kamjunke, Norbert A1 - Gaedke, Ursula A1 - Tittel, Jörg A1 - Weithoff, Guntram A1 - Bell, Elanor M. T1 - Strong vertical differences in the plankton composition of an extremely acidic lake N2 - 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. Y1 - 2004 ER - TY - JOUR A1 - Eckermann, Nora A1 - Fettke, Jörg A1 - Pauly, Markus A1 - Bazant, Esther A1 - Steup, Martin T1 - Starch-metabolism related isozymes in higher plants Y1 - 2004 ER - TY - JOUR A1 - Jandrig, Burkhard A1 - Seitz, Susanne A1 - Hinzmann, Bernd A1 - Arnold, Wolfgang A1 - Micheel, Burkhard A1 - Koelble, Konrad A1 - Siebert, Reiner A1 - Schwartz, Arnfried A1 - Ruecker, Karin A1 - Schlag, Peter M. A1 - Scherneck, Siegfried A1 - Rosenthal, Andra T1 - ST18 is a breast cancer tumor suppressor gene at human chromosome 8q11.2 N2 - We have identified a gene, ST18 (suppression of tumorigenicity 18, breast carcinoma, zinc-finger protein), within a frequent imbalanced region of chromosome 8q11 as a breast cancer tumor suppressor gene. The ST18 gene encodes a zinc-finger DNA-binding protein with six fingers of the C2HC type (configuration Cys-X5-Cys-X12-His-X4-Cys) and an SMC domain. ST18 has the potential to act as transcriptional regulator. ST18 is expressed in a number of normal tissues including mammary epithelial cells although the level of expression is quite low. In breast cancer cell lines and the majority of primary breast tumors, ST18 mRNA is significantly downregulated. A 160 bp region within the promoter of the ST18 gene is hypermethylated in about 80% of the breast cancer samples and in the majority of breast cancer cell lines. The strong correlation between ST18 promoter hypermethylation and loss of ST18 expression in tumor cells suggests that this epigenetic mechanism is responsible for tumor-specific downregulation. We further show that ectopic ST18 expression in MCF-7 breast cancer cells strongly inhibits colony formation in soft agar and the formation of tumors in a xenograft mouse model Y1 - 2004 UR - http://www.nature.com/cgi-taf/DynaPage.taf?file=/onc/journal/v23/n57/abs/ 1208131a.html&dynoptions=doi1113987275 ER - TY - JOUR A1 - Bistolas, Nikitas A1 - Christenson, A. A1 - Ruzgas, T. A1 - Jung, Christiane A1 - Scheller, Frieder W. A1 - Wollenberger, Ursula T1 - Spectroelectrochemistry of cytochrome P450cam N2 - 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 Y1 - 2004 ER - TY - JOUR A1 - Lagus, A. A1 - Suomela, J. A1 - Weithoff, Guntram A1 - Heikkila, K. A1 - Helminen, H. A1 - Sipura, J. T1 - Species-specific differences in phytoplankton responses to N and P enrichments and the N:P ratio in the Archipelago Sea, northern Baltic Sea N2 - A nutrient enrichment experiment was conducted in order to study the role of nitrogen (N), phosphorus (P) and the N:P ratio on the early summer phytoplankton community in the Archipelago Sea, northern Baltic Sea. The phytoplankton community was, in terms of chlorophyll a and total biomass, primarily N-limited, but the individual species varied in their responses to the nutrient supply. The recorded overall N limitation was due to fast growth responses of a few N- limited species such as the diatom Chaetoceros wighamii (Brightwell) and the mixotrophic chrysophyte Uroglena sp. Another dominating diatom, Skeletonema costatum (Greville) Cleve was most clearly P-limited. The N:P ratio had the strongest effect on Uroglena sp., which grew exponentially in the enrichments with a high N:P ratio. This can be explained by the ability of the species to feed on P-rich bacteria, which gives it a competitive advantage in P-limited conditions. The species-specific differences in the responses to the nutrient enrichments can generally be explained by differences in the species physiology and they were consistent with the theory of resource competition. Y1 - 2004 UR - http://plankt.oupjournals.org/cgi/reprint/26/7/779 ER - TY - JOUR A1 - Mora, Emanuel C. A1 - Macias, S. A1 - Vater, Marianne A1 - Coro, Frank A1 - Kossl, Manfred T1 - Specializations for aerial hawking in the echolocation system of Molossus molossus (Molossidae, Chiroptera) N2 - 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 Y1 - 2004 SN - 0340-7594 ER - TY - JOUR A1 - Lieckfeldt, Elke A1 - Simon-Rosin, Ulrike A1 - Zöller, Daniela A1 - Ebert, Berit A1 - Kehr, Julia A1 - Fisahn, Joachim T1 - Spatio/temporal analysis of gene exression profiles within single cells and specific tissue types of developing Arabidopsis plants Y1 - 2004 SN - 3-00-011587-0 ER - TY - JOUR A1 - Baumann, Otto T1 - Spatial pattern of nonmuscle myosin-II distribution during the development of the Drosophila compound eye and implications for retinal morphogenesis N2 - 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 Y1 - 2004 ER - TY - JOUR A1 - Schurr, Frank Martin A1 - Bossdorf, Oliver A1 - Milton, Sue J. A1 - Schumacher, J. T1 - Spatial pattern formation in semi-arid shrubland : a priori predicted versus observed pattern characteristics N2 - Ecologists increasingly use spatial statistics to study vegetation patterns. Mostly, however, these techniques are applied in a purely descriptive fashion without a priori statements on the pattern characteristics expected. We formulated such a priori predictions in a study of spatial pattern in a semi-arid Karoo shrubland, South Africa. Both seed dispersal and root competition have been discussed as processes shaping the spatial structure of this community. If either of the two processes dominates pattern formation, patterns within and between shrub functional groups are expected to show distinct deviations from null models. We predicted the type and scale of these deviations and compared predicted to observed pattern characteristics. As predicted by the seed dispersal hypothesis, small-scale co-occurrence within and between groups of colonisers and successors was increased as compared to complete spatially random arrangement of shrubs. The root competition predictions, however, were not met as shrubs of similar rooting depth co- occurred more frequently than expected under random shrub arrangement. Since the distribution of rooting groups to the given shrub locations also failed to match the root competition predictions, there was little evidence for dominance of root competition in pattern formation. Although other processes may contribute to small-scale plant co-occurrence, the sufficient and most parsimonious explanation for the observed pattern is that its formation was dominated by seed dispersal. To characterise point patterns we applied both cumulative (uni- and bivariate K-function) and local (pair- and mark-correlation function) techniques. Based on our results we recommend that future studies of vegetation patterns include local characteristics as they independently describe a pattern at different scales and can be easily related to processes changing with interplant distance in a predictable fashion. Y1 - 2004 ER - TY - JOUR A1 - Rhoades, E. A1 - Cohen, M. A1 - Gussakovsky, E. A1 - Schuler, Benjamin A1 - Haran, G. T1 - Single molecule protein folding Y1 - 2004 SN - 0006-3495 ER - TY - JOUR A1 - Mick, V. A1 - Eggert, K. A1 - Heinemann, B. A1 - Geister, S. A1 - Paulsen, H. T1 - Single amino acids in the lumenal loop domain influence the stability of the major light-harvesting chlorophyll alb complex N2 - 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 Y1 - 2004 SN - 0006-2960 ER - TY - JOUR A1 - Schmidt, R. A1 - Walz, Bernd T1 - Serotonin and histamine produce different spatiotemporal Ca2+ signals in blowfly salivary glands Y1 - 2004 SN - 0171-9335 ER - TY - JOUR A1 - Köchy, Martin A1 - Wilson, Scott D. T1 - Semiarid grassland responses to short-term variation in water availability N2 - Standing crop and species composition in semiarid grassland are linked to long-term patterns of water availability, but grasslands are characterized by large single-season variability in rainfall. We tested whether a single season of altered water availability influenced the proportions of grasses and shrubs in a semiarid grassland near the northern edge of the North American Great Plains. We studied stands of the clonal shrub snowberry (Symphoricarpos occidentalis) and adjacent grassland dominated by the native grasses Stipa spartea and Bouteloua gracilis. Rain was excluded and water supplied in amounts corresponding to years of low, medium, and high rainfall, producing a 2 - 4-fold range in monthly precipitation among water supply treatments. There were ten replicate plots of each water treatment in both snowberry stands and grassland. Grass standing crop increased significantly with water availability in grassland but not inside snowberry stands. Total standing crop and shrub stem density increased significantly with water supply, averaged across both communities. In contrast, water had no effect on shrub standing crop or light penetration. In summary, our finding that water has significant effects on a subset of components of grassland vegetation is consistent with long-term, correlational studies, but we also found that a single season of altered water supply had no effect on other important aspects of the ecosystem. Y1 - 2004 UR - http://springerlink.metapress.com/app/home/ content.asp?wasp=1147bd873d6c4f488659db36d63e080d&referrer=contribution&format=2&page=1&pagecount=7 SN - 1385-0237 ER - TY - JOUR A1 - Jeltsch, Florian A1 - Wiegand, K. A1 - Ward, D. T1 - Seed dispersal by cattle may cause shrub encroachment of Grewia flava on southern Kalahari rangelands Y1 - 2004 ER - TY - JOUR A1 - Jeltsch, Florian A1 - Tews, Jörg A1 - Schurr, Frank Martin T1 - Seed dispersal by cattle may cause shrub encroachment of Grewia flava on southern Kalahari rangelands N2 - 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 Y1 - 2004 ER - TY - JOUR A1 - Usadel, Björn A1 - Kuschinsky, Anja M. A1 - Rosso, Mario G. A1 - Eckermann, Nora A1 - Pauly, Markus T1 - RHM2 is involved in mucilage pectin synthesis and is required for the development of the seed coat in Arabidopsis N2 - 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 Y1 - 2004 ER - TY - JOUR A1 - Lehnhardt, Lothar A1 - Pufe, Heidrun A1 - Bauman, Ingrid A1 - Baumann, Guido T1 - Responses of chloroplast thylakoid composition to low temperature and high light stress in callus cultures and in leaves of sugar beet Y1 - 2004 ER - TY - JOUR A1 - Kohler, B. A1 - Müller-Röber, Bernd T1 - Remote control - cell and organ communication within plants Y1 - 2004 ER - TY - JOUR A1 - Dames, Petra A1 - Schmidt, R. A1 - Walz, Bernd A1 - Baumann, Otto T1 - Regulation of vacuolar-type H+-ATPase (vATPase) in blowfly salivary glands Y1 - 2004 SN - 0171-9335 ER - TY - JOUR A1 - Ketelhut, Kerstin A1 - Mohasseb, Iman A1 - Scheffler, Christiane A1 - Ketelhut, Reinhard G. T1 - Regular exercise improves risk profile and motor development in early childhood Y1 - 2004 ER - TY - JOUR A1 - Fischer, Markus A1 - Pfisterer, A. A1 - Joshi, Jasmin Radha A1 - Schmid, Bernhard T1 - Rapid decay of diversity-productivity relationships after invasion of experimental plant communities Y1 - 2004 ER - TY - JOUR A1 - Jeltsch, Florian A1 - Hansen, Frank A1 - Tackmann, K. A1 - Staubach, C. A1 - Thulke, Hans-Hermann T1 - Processes leading to a spatial aggregation of Echinococcus multilocularis in its natural intermediate host Microtus arvalis N2 - 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 Y1 - 2004 ER - TY - JOUR A1 - van Kleunen, Mark A1 - Ritland, K. T1 - Predicting evolution of floral traits associated with mating system in a natural plant population N2 - 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 Y1 - 2004 SN - 1010- 061x ER - TY - JOUR A1 - Diez, Isabel A1 - Tauer, Klaus A1 - Schulz, Burkhard T1 - Polypyrrole tubes via casting of pyrrole-beta-naphthalenesulfonic acid rods N2 - 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 Y1 - 2004 SN - 0303-402X ER - TY - JOUR A1 - Modler, Andreas Johannes A1 - Fabian, H. A1 - Sokolowski, F. A1 - Lutsch, G. A1 - Gast, Klaus A1 - Damaschun, Gregor T1 - Polymerization of proteins into amyloid protofibrils shares common critical oligomeric states but differs in the mechanisms of their formation N2 - 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 Y1 - 2004 ER - TY - JOUR A1 - Ritte, Gerhard A1 - Scharf, Anke A1 - Eckermann, Nora A1 - Haebel, Sophie A1 - Steup, Martin T1 - Phosphorylation of transitory starch is increased during degradation N2 - 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 Y1 - 2004 ER - TY - JOUR A1 - Kleuser, U. A1 - Stöcklein, Walter F. M. A1 - Pieper-Fürst, U. A1 - Scheller, Frieder W. T1 - Partikelverstärkte Oberflächenplasmonresonanz für die Quantifizierung von Matrix Metalloproteinase-2 Y1 - 2004 ER - TY - JOUR A1 - Prochnow, Annette A1 - Brunk, Ingo A1 - Segert, Astrid T1 - Offenhaltung durch Mähen und Räumen bzw. Mulchen Y1 - 2004 SN - 3-540-22449-1 ER - TY - JOUR A1 - Wanner, Manfred A1 - Burkart, Bettina A1 - Hinrichsen, Arne A1 - Prochnow, Annette A1 - Schlauderer, Ralf A1 - Wiesener, Cornelia A1 - Zierke, Irene A1 - Xylander, Willi E. R. T1 - Offenhaltung durch mechanische Bodenfreilegung Y1 - 2004 SN - 3-540-22449-1 ER -