TY - JOUR A1 - Malitschek, Barbara A1 - Wittbrodt, Joachim A1 - Fischer, Petra A1 - Lammers, Reiner A1 - Ullrich, Axel A1 - Schartl, Manfred T1 - Autocrine stimulation of the Xmrk receptor tyrosine kinase in Xiphophorus melanoma cells and identification of a source for the physiological ligand N2 - The melanoma·inducing gene of Xiphophorus fish encodes the Xmrk receptor tyrosine kinase. U sing a highly specific antiserum p~oduced against the recombinant receptor expressed with a baculovirus, it is shown that Xmrk is the most abundant phosphotyrosine protein in fish melanoma and thus highly activated in the tumors. Studies on a melanoma cellline revealed that these cells produce an activity that considerably stimulates receptor autophosphorylation. The stimulating activity induces receptor down-regulation and can be depleted from the melanoma cellsupernatant by the immobilized recombinant receptor protein. The fish melanoma cells can thus be considered autocrine tumor cells providing a source for future purification and characterization of the Xmrk ligand. KW - Physiologische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61551 ER - TY - JOUR A1 - Meyer, Axel A1 - Morrissey, Jean M. A1 - Schartl, Manfred T1 - Recurrent origin of a sexually selected trait in Xiphophorus fishes inferred from a molecular phylogeny N2 - DARWIN\(^1\) believed that sexual selection accounts for the evolution of exaggerated male ornaments, such as the sword-like caudal fin extensions of male fishes of the genus Xiphophorus, that appear detrimental to survival. Swordtails continue to feature prominently in empirical work and theories of sexual selection; the pre-existing bias hypothesis has been offered as an explanation for the evolution of swords in these fishes\(^{2,3}\). Based upon a largely morphological phylogeny, this hypothesis suggests that female preference to mate with sworded males arose in ancestrally swordless species, thus pre-dating the origin of the sword itself and directly driving its evolution. Here we present a molecular phylogeny (based on mitochondrial and nuclear DNA sequences) of Xiphophorus which differs from the traditional one: it indicates that the sword originated and was lost repeatedly. Our phylogeny suggests that the ancestor of the genus is more likely to have possessed a sword than not, thus questioning the applicability of the pre-existing bias hypothesis as an explanation for the cvolution of this sexually selected trait. KW - Physiologische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61569 ER - TY - JOUR A1 - Lampidis, Robert A1 - Gross, Roy A1 - Sokolovic, Zeljka A1 - Goebel, Werner A1 - Kreft, Jürgen T1 - The virulence regulator protein of Listeria ivanovii is highly homologous to PrfA from Listeria monocytogenes and both belong to the Crp-Fnr family of transcription regulators N2 - No abstract available KW - Biologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-60503 ER - TY - JOUR A1 - Fiala, Brigitte A1 - Grunsky, Harald A1 - Maschwitz, Ulrich A1 - Linsenmair, Karl Eduard T1 - Diversity of ant-plant interactions: Protective efficacy in Macaranga species with different degrees of ant-association. N2 - The pioneer tree Macaranga in SE Asia has developed manyfold associations with ants. The genus comprises all stages of interaction with ants, from facultative relationships to obligate myrmecophytes. Only myrmecophytic Macaranga offer nesting space for ants and are associated with a specific ant partner. The nonmyrmecophytic species are visited by a variety of different ant species which are attracted by extrafloral nectaries (EFN) and food bodies. Transitional Macaranga species like M. hosei are colonized later in their development due to their stem structure. Before the colonization by their specific Crematogaster partner the young plants are visited by different ant species attracted by EFN. These nectaries are reduced and food body production starts as soon as colonization becomes possible. We demonstrated earlier that obligate ant partners can protect their Macaranga plants against herbivore damage and vine cover. In this study we focused on nonspecific interactions and studied M. tanarius and M. hosei, representing a non-myrmecophyte and a transitional species respectively. In ant exclusion experiments both M. tanarius and M. hosei suffered significantly higher mean leaf damage than controls, 37% versus 6% in M. hosei, 16% versus 7% in M. tanarius. M. tanarius offers both EFN and food bodies so that tests for different effects of these two food rewards could be conducted. Plants with food bodies removed but with EFN remaining had the lowest mean increase of herbivore damage of all experimental groups. Main herbivores on M. hosei were mites and caterpillars. Many M. tanarius plants were infested by a shootborer. Both Macaranga species were visited by various ant species. Crematogaster spp. being the most abundant. We found no evidence for any specific relationships. The results of this study strongly support the hypothesis that non-specific, facultative associations with ants can be advantageous for Macaranga plants. Food bodies appear to have lower attractive value for opportunistic ants than EFN and may require a specific dietary adaptation. This is also indicated by the fact that food body production in the transitional M. hosei does not start before stem structure allows a colonization by the obligate Crematogaster species. M. hosei thus benefits from facultative association with a variety of ants until it produces its first domatia and can be colonized by its obligate mutualist. KW - Ant-plant interactions ; Herbivory Macaranga ; Mutualism ; Myrmecophytes Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-32905 ER - TY - JOUR A1 - Higgins, M. J. A1 - Smilinich, N. J. A1 - Sait, S. A1 - Koenig, A. A1 - Pongratz, J. A1 - Gessler, Manfred A1 - Richard III., C. W. A1 - James, M. R. A1 - Sanford, J. P. A1 - Kim, B.-W. A1 - Cattelane, J. A1 - Nowak, N. J. A1 - Winterpacht, A. A1 - Zabel, B. U. A1 - Munroe, D. J. A1 - Bric, E. A1 - Housman, D. E. A1 - Jones, C. A1 - Nakamura, Y. A1 - Gerhard, D. S. A1 - Shows, T. B. T1 - An Ordered NotI Fragment Map of Human Chromosome Band 11p15 N2 - An ordered NotI fragment map containing over 60 loci and encompassing approximately 17 Mb has been constructed for human chromosome band llpl5. Forty-two probes, including 11 NotI-linking cosmids, were subregionaUy mapped to llpl5 using a subset of the Jl-deletion hybrids. These and 23 other probes defining loci previously mapped to 11p15 were hybridized to genomic DNA digested with NotI and 5 other infrequently cleaving restriction enzymes and separated by pulsed-field gel electrophoresis. Thirty-nine distinct NotI fragments were detected encompassing approximately 85% of the estimated length of llp15. The predicted order of the gene loci used is cenMYODI- PTH-CALCA-ST5-RBTNI-HPX-HBB-RRMlTH/ INS!1GF2-H19-CTSD-MUC2-DRD4-HRAS-RNHtel. This map wiu allow higher resolution mapping of new Ilp15 markers, facilitate positional cloning of disease genes, and provide a framework for the physical mapping of llp15 in clone contigs. KW - Genom / Genkartierung / Genanalyse Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-45766 ER - TY - JOUR A1 - Maschwitz, Ulich A1 - Fiala, Brigitte A1 - Saw, L. G. A1 - Norma-Rashid, Yusoff A1 - Idris, Azarae Haji T1 - Ficus obscura var. borneensis (Moraceae), a new non-specific ant-plant from Malesia N2 - Ficus obscura var. borneensis is a true myrmecophyte. It spontaneously forms cavities (domatia) in parts of its twigs which open by slits, These occur in the internodes and are usually not swollen. The domatia are inhabited by a variety of non-specific tree-living ants including Crematogaster spp., Cataulacus sp., Tetramorium sp., Cardio condyla sp. and Camponotus sp.. Additionally the plant providL a su~ar-containing secretion from extrafloral nectaries on the lower surfaces of the leaves. Examination of herbarium specimens of 37 other South-east Asian Ficus species did not reveal a single specimen with domatia. Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-42926 ER - TY - JOUR A1 - Maschwitz, Ulrich A1 - Fiala, Brigitte A1 - Linsenmair, Karl Eduard T1 - Clerodendrum fistulosum (Verbenanceae), an unspecific myrmecophyte from Borneo with spontaneously opening domatia N2 - Clerodendrumjistulosum Becc. is a true myrmecophyte as it offers nesting space for ants in hollow intemodes. In contrast to previous reports our investigations proved that these domatia open by themselves, thus providing cavities for a variety of different ant species. In Sarawak, Malaysia, we did not find an obligate relationship between C. jistulosum and a specific ant-partner. For comparison, studies on herbarium material of other Clerodendrum species were carried out a further species, C. deflexum from the Malay Peninsula and Sumatra presumably also is myrmecophytic. Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31013 ER - TY - JOUR A1 - Linsenmair, Karl Eduard T1 - Biologische Vielfalt und ökologische Stabilität N2 - No abstract available Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31157 ER - TY - JOUR A1 - Fiala, Brigitte A1 - Linsenmair, Karl Eduard A1 - Maschwitz, Ulrich T1 - Diversität von Interaktionen zwischen Ameisen und Pflanzen im südostasiatischen Regenwald T1 - Diversity of ant-plant interactions in south-east Asian rainforests N2 - Assoziationen von Ameisen mit Pflanzen (und oft noch mit pflanzensaugenden Insekten als drittem Partner) dürften eine Ursache des Artenreichtums und der hohen Abundanzen tropischer Formicidae sein. Die von den Ameisen genutzten Pflanzen bieten entweder Nahrung an, über extraflorale Nektarien und/oder Nährkörperchen, oder aber - bei den eigentlichen Myrmekophyten - Nistraum und z.T. auch Nahrung. Diese Beziehungen zeichnen sich durch unterschiedliche Nutzungsweisen und Nutzungsintensitäten und damit stark differierende Abhängigkeit der Partner voneinander aus. Ein besonders breites Spektrum von Ameisen-Pflanzen-Assoziationen finden wir in der paläotropischen Baumgattung Macaranga (Euphorbiaceae), die sich daher als Modellsystem für vergleichende Untersuchungen hervorragend eignet. Die Grundfrage unserer Untersuchungen an diesem System lautet: Verläuft aufgrund der ausgeprägt mosaikartigen Verteilung der von den myrmekophilen Pflanzen angebotenen Nahrungs- und Nistraumressourcen die Neu- und Wiederbesiedlung von Habitaten durch die Ameisen in Form von Zufallsprozessen? Oder werden, im Gegenteil, durch diesen Umstand Spezialisierungen seitens der Ameisen gefördert und die Zusammensetzung der Lebensgemeinschaften dadurch stärker deterministisch geprägt? Unsere bisherigen Untersuchungen zeigen, daß beide Prinzipien wirken. Bei der alleinigen Nutzung von Nahrungsressourcen fehlen spezialisierte Beziehungen weitgehend und stochastische Ereignisse dürften sehr häufig die Pflanzen-Ameisen-Assoziation bestimmen. Bei den eigentlichen Myrmekophyten hingegen ist die Auswahl der assozierten Ameisen viel stärker determiniert, ganz besonders dann, wenn der Wohnraum, den die Pflanze offeriert, nur durch aktives Öffnen seitens der Ameisen erschlossen werden kann. N2 - Associations of ants with plants can be regarded as one reason for the high abundance and diversity of ants in the tropics. The plants either provide food as extrafloral nectar and/or food bodies or, in the true myrmecophytes, nesting space and partly also food. These associations are characterized by very different forms and intensities of use of the plant resources and, therefore, also varying mutual dependency of the partners. A broad spectrum of different ant-plant associations is found in the paleotropical tree genus Macaranga (Euphorbiaceae) wh ich is therefore especially suited as a model system for a comparative investigation. The central question of our studies is: Does the mosaic character of the spatial distribution of food and nesting resources provided by the myrmecophilous plants rather favour stochastic processes during colonization of habitats by ants? Or does it, on the contrary, preferentially lead to strong specializations in the ants? Our investigations show that both principles are realized. In interactions where ants only use the food resources, specific relationships are lacking and stochastic events direct the associations. In obligate myrmecophytes, however, the colonization largely follows deterministic principles, especially when nesting space inside the plant actively has to be made accessible by the ants. Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-32894 ER - TY - CHAP A1 - Dabauvalle, M.-C. A1 - Wilken, N. A1 - Ewald, A. A1 - Kuhbier, A. A1 - Senécal, J.-L. A1 - Scheer, Ulrich T1 - Nuclear pore complex structure analyzed by immunogold EM with human autoantibodies N2 - No abstract available Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39439 ER - TY - JOUR A1 - Scheer, Ulrich A1 - Weisenberger, Dieter T1 - The nucleolus N2 - No abstract available Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-32037 ER - TY - JOUR A1 - Dandekar, Thomas A1 - Argos, Patrick T1 - Amiloride-sensitive epithelial Na\(^+\) channel is made of three homologous subunits N2 - No abstract available Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-29734 ER - TY - GEN A1 - Dandekar, Thomas A1 - Dandekar, G. T1 - Schlange als Attribut des Äskulap N2 - No abstract available Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-29822 ER - TY - JOUR A1 - Dandekar, Thomas A1 - Argos, P. T1 - Three-dimensional structure of the 67k N-terminal Fragment of E.coli DNA Topoisomerase I N2 - No abstract available Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-29836 ER - TY - JOUR A1 - Dandekar, Thomas A1 - Argos, P. T1 - Folding the main chain of small proteins with the genetic algorithm N2 - No abstract available Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-29847 ER - TY - JOUR A1 - Vortkamp, Andrea A1 - Gessler, Manfred A1 - Paslier, D. Le A1 - Elaswarapu, R. A1 - Smith, S. A1 - Grzeschik, Karl-Heinz T1 - Isolation of a yeast artificial chromosome contig spanning the Greig cephalopolysyndactyly syndrome (GCPS) gene region N2 - Disruption of the zinc finger gene GLI3 has been shown to be the cause of Greig cephalopolysyndactyly syndrome (GCPS), at least in some GCPS translocation patients. To characterize this genomic region on human chromosome 7p13, we have isolated a VAC contig of more than 1000 kb including the GLI3 gene. In this contig the gene itself spans at least 200-250 kb. A CpG island is located in the vicinity of the 5' region of the known GLI3 cDNA, implying a potential promoter region. Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-30182 ER - TY - JOUR A1 - Schmuck, R. A1 - Geise, W. A1 - Linsenmair, Karl Eduard T1 - Life cycle strategies and physiological adjustments of Reedfrog Tadpoles (Amphibia, Anura, Hyperoliidae) in relation to environmental conditions. N2 - The relationship between different degrees of intraspecific crowding of reedfrog tadpoles and their physiological responses to a deterioration of the natal pond water quality was examined under laboratory conditions. Tadpoles that were reared at a lower density metamorphosed significantly earlier than those raised at a higher density. As density increases, the average body length at metamorphosis decreases. However, at low tadpole density, a significantly higher diversity of body size classes among freshly metamorphosed froglets was observed than under more crowded conditions. Mortality increased during metamorphic climax and was inversely correlated with the tadpole density. In ephemeral ponds, an accumulation of nitrogenous wastes from metabolic processes and/or a concentration by evaporation in prolonged rainless periods can pose a considerable chemical stress to reedfrog tadpoles. Hyperolius viridiflavus ommatostictus responded to an increasing ammonia concentration with an activity increase of the ornithine cycle (intensified urea synthesis). hi contrast, Hyperolius marmoratus taeniatus exhibited a strong tolerance against high ammonia levels. A deterioration of the natal pond water quality caused H. v. ommatostictus and H. v. nitidulus tadpoles to adjust to harsher climatic conditions at the time of metamorphosis. This physiological preadjustment enabled the froglets to start feeding and growing immediately after metamorphosis even at low air humidity and rare precipitation events. In contrast, froglets that were raised in daily refreshed water exhibited high mortality rates if subjected to identical conditions. As one possible indicator of the actual climatic conditions prevailing in the surrounding terrestrial habitat, fluctuations in the water ammonia level are discussed. Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31009 ER - TY - JOUR A1 - Scheer, Ulrich T1 - Harold Garnet Callan 1917-1993 N2 - Professor Harold Gamet Callan, honorary member of the German Society for Cell Biology, died on the 3rd November 1993, at the age of 76. His name is inseparably connected with lampbrush chromosomes, the most spectacular and aesthetically ailuring form of chromosomes, which occupied the major part of his scientific career. " Mick" Callan's pioneering studies led to fruitful new concepts, served as a building block for many subsequent studies by others, and contributed enormously to our current understanding of chromosome organization and activity ... KW - Harold Garnet Callan Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-80789 ER - TY - CHAP A1 - Schreibman, Martin P. A1 - Schartl, Manfred A1 - Kallman, Klaus D. A1 - Magliulo-Cepriano, Lucia T1 - Molecular approaches to study the genetic regulation of the fish reproductive system N2 - No abstract available. KW - Fische Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86679 ER - TY - CHAP A1 - Altschmied, Joachim A1 - Schartl, Manfred T1 - Genetics and molecular biology of tumour formation in Xiphophorus N2 - No abstract available. KW - Schwertkärpfling KW - Tumor KW - Entstehung KW - Molekularbiologie KW - Genetik Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-69752 ER - TY - JOUR A1 - Argos, P. A1 - Dandekar, Thomas T1 - Delineating the main chain topology of four-helix bundle proteins using the genetic algorithm and knowledge based on the amino acid sequence alone N2 - No abstract available KW - Proteine KW - Strukturanalyse KW - Abstandsmessung Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-33807 ER - TY - CHAP A1 - Fiala, Brigitte A1 - Rabenstein, R. A1 - Maschwitz, Ulrich T1 - Ant-attracting plant-structures: Food bodies of SE Asian Vitaceae N2 - No abstract available KW - Pflanzen Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-55177 ER - TY - JOUR A1 - Winkler, Christoph A1 - Wittbrodt, Joachim A1 - Lammers, Reiner A1 - Ullrich, Axel A1 - Schartl, Manfred T1 - Ligand-dependent tumor induction in medakafish embryos by a Xmrk receptor tyrosine kinase transgene N2 - Xmrk encodes a subclass 1 receptor tyrosine kinase (RTK) which has been cloned from the melanomainducing locus Tu of the poeciliid fish Xiphophorus. To demonstrate a high oncogenic potential in vivo we transferred the gene into early embryos of the closely related medakafish. Ectopic expression of the Xmrk oncogene under the control of a strong, constitutive promoter (CMVTk) led to the induction of embryonic tumors with high incidence, after short latency periods, and with a specific pattern of affected tissues. We demonstrate ligand-dependent transformation in vivo using a chimeric receptor consisting of the extracellular and transmembrane domains of the human EGF receptor (HER) and the cytoplasmatic domain of Xmrk. Expression of the chimeric receptor alone does not lead to ldnase activation or induction of tumors. Coexpression of the chimera with its corresponding ligand, human transforming growth factor alpha (bTGF(X), however, results in the activation of the chimeric RTK. In injected fish embryos the induction of the neoplastic growth is observed with similar incidence and tissue distribution as in embryos carrying the native Xmrk oncogene suggesting that the ligand as well as factors downstream of tbe RTK are required for tumor formation. In this study we show single-step induction of tumors by ectopic expression of RTKs in vivo substantiating tbe significance of autocrine stimulation in RTK induced tumors in vertebrales. KW - Japankärpfling KW - Ligand KW - Tumor Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-87107 ER - TY - JOUR A1 - Gessler, Manfred A1 - König, A. A1 - Arden, K. A1 - Grundy, P. A1 - Orkin, S. H. A1 - Sallan, S. A1 - Peters, C. A1 - Ruyle, S. A1 - Mandell, J. A1 - Li, F. A1 - Cavenee, W. A1 - Bruns, G. A. T1 - Infrequent mutation of the WT1 gene in 77 Wilms' Tumors N2 - Homozygous deletions in Wilms' tumor DNA have been a key step in the identification and isolation of the WTI gene. Several additional loci are also postulated to contribute to Wilms' tumor formation. To assess the frequency of WTI alterations we have analyzed the WTI locus in a panel of 77 Wilms' tumors. Eight tumors showed evidence for large deletions of several hundred or thousand kilobasepairs of DNA, some of which were also cytogenetically detected. Additional intragenic mutations were detected using more sensitive SSCP analyses to scan all 10 WTI exons. Most of these result in premature stop codons or missense mutations that inactivate the remaining WTI allele. The overall frequency of WTI alterations detected with these methods is less than 15%. While some mutations may not be detectable with the methods employed, our results suggest that direct alterations of the WTI gene are present in only a small fraction of Wilms' tumors. Thus, mutations at other Wilms' tumor loci or disturbance of interactions between these genes likely play an important role in Wilms' tumor development. KW - Wilms' tumor KW - WTI KW - Zinc finger gene KW - Tumor suppressor gene KW - Nephroblastoma KW - Deletion analysis KW - SSCP analysis KW - Mutation screening Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-34308 ER -