Risikoanalysen zur Freisetzung gentechnologisch veraenderter Rhizobien: Analyse der Wechselwirkung zwischen gentechnisch veraendertem Organismus und Modelloekosystemen Zusammenstellung von Veroeffentlichungen

First environmental release experiments in Germany involve genetically modified derivatives of the soil bacterium Rhizobium meliloti. One focus of the experiment is to test a biosafety concept and environmental conditions. Prior to the environmental release laboratory-based microcosm studies assess the impact of the genetically engineered microorganisms on the indigenous bacterial population of the target eco-system. It is concluded that RecA"- strains of Rhizobium are safe hosts for deliberate release experiments. The compiled publications present the data of genetically engineering up to first greenhouse experiments. (WEN)SIGLEAvailable from TIB Hannover: F96B487 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Halophila stipulacea - Eine neue Nahrungsquelle in der Fischzucht Schlussbericht

The diversity of microorganisms on the surface of the seagrass Halophila stipulacea, which is common in the Gulf of Eilat, was analyzed and characterized by molecular methods. Using a cultivation-independent protocol, microorganisms were isolated from the surface of the plant. The 16S-rDNA of the microorganisms was isolated directly by PCR. The 16S-rDNA products cloned were characterized by an analysis of restriction fragments (ARDRA = amplified ribosomal DNA-restriction analysis), which allowed a classification on the species level. From the total of 103 16S-rDNA products isolated from microorganisms of the leaf surface, 58 different groups were distinguished. From microorganisms associated with the surface of rhizomes, 105 PCR-products were analyzed, which were classified in 62 groups. Only 10 members of the 'rhizome' group were also detected in the 'leaf' group. Similar results were obtained by analyzing the 16S-rDNA products of microorganisms associated with the roots of H. stipulacea. DNA sequencing of 30 16S-rDNA products obtained from organisms from the leaf surface and subsequent database searches revealed homologies to members of the alpha, gamma and delta subgroups of proteobacteria. From a taxonomic point of view, some of these members can be associated to so far unknown bacterial species. (orig.)SIGLEAvailable from TIB Hannover: DtF QN1(38,10) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Symbiontische Wechselwirkungen zwischen Mikroorganismen und Kulturpflanzen: Genetische Optimierung der Knoellchensymbiose fuer Luzerne und Ackerbohne Abschlussbericht

Available from TIB Hannover: D.Dt.F.QN1(17,57) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Vorlaufforschung fuer einen Freisetzungsversuch und Begleitforschung mit Transgenen T4-Lysozym produzierenden Kartoffeln. Entwicklung eines Modellsystems zur Analyse der Auswirkungen von transgen-kodierten Bakterioziden oder Bakteriostatika auf Mikroorganismen am Beispiel der Wirkung von T4-Lysozym auf Rhizobium spec Abschlussbericht

Transgenic potato plants expressing T4 lysozyme display enhanced resistance against the plant pathogen Erwinia carotovora (Duering et al. 1993). T4-lysozyme, as other lysozymes, is a bacteriolytic enzyme destroying bacterial cell walls and may not exclusively harm bacterial pathogens, but also soil bacteria necessary for plant growth and health. We analyzed the impact of T4-lysozym on Rhizobium leguminosarum as a model organism. Growing in liquid medium, R. leguminosarum was extremely sensitive against lysozymes. The impact of crude extracts from transgenic potatoes on R. leguminosarum could be demonstrated. Lysozyme sensitivity was reduced up to ten times in synthetic soil extracts and nearly not detectable in sterile or unsterile soil. The expression of T4 lysozyme in transgenic roots led to a 50% reduction of the nodulation rate. These results are a prerequisite for the analysis of T4-lysozyme producing plant in the field. The methods developed should be useful for the analysis of other transgene encoded substances and their impact on soil bacteria. (orig.)SIGLEAvailable from TIB Hannover: DtF QN1(59,42) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Sensorisch/motorische Koordination von Roboterbewegungen mit neuronalen Netzen. Teilprojekte 1, 6 und 7 Abschlussbericht

In the project 'pathplaning' a model has been developed which permits to find a path between a start- and an endpoint in a plane cluttered with obstacles. Qualitatively, the form of the paths corresponds to those paths obtained in experiments with human subjects. In the project 'the human arm as a redundant manipulator' a recurrent net has been developed, which simulates the kinematics of a redundant manipulator' a recurrent net has been developed, which simulates the kinematics of a redundant arm. By means of its holistic nature, the system, called MMC net, is able to solve the direct and the inverse kinematics problem as well as any mixed problem. In the project 'coordination of several legs' a model has been developed, which is able to control the movement of the six legs of an insect-like walking robot by means of neural networks of modular architecture. In these projects new principles could be developed applicable for the control of a multijoint, redundant manipulators and to control the six-legged walking robot. Some of these could be tested on a pototype; the Technical University of Munch walking robot (Prof. Pfeiffer). (orig.)Available from TIB Hannover: F97B455+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Oekologische Optimierung der Wassernutzung bei Bewaesserungsverfahren mit salzhaltigem Wasser Endbericht. Ausfuehrlicher Bericht

SIGLEAvailable from TIB Hannover: F02B705 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany); Forschungszentrum Juelich GmbH (KFA) (Germany). Projekttraeger Biologie, Energie, Oekologie (BEO)DEGerman

Analyse der Gene fuer Stickstoff-Fixierung und Untersuchungen zur Genexpression in nicht symbiontisch N_2-fixierenden Mikroorganismen Abschlussbericht

The main objective of this project was the comparative analysis of the organization and regulation of nitrogen fixation genes (nif) from Rhodobacter capsulatus and Azotobacter vinelandii which should be carried out in collaboration with Prof.Dr.H.K. Das (New Delhi, India). A new class of nif genes involved in electron transfer to nitrogenase was identified in R.capsulatus. The expression of all nif genes from R.capsulatus is regulated by eight sigma_5_4 promoters which are dependent on the transcriptional activator protein NifA. Transcription of both copies of nifA is inititated at promoter sequences showing no homology to known transcriptional initiation signals. In addition to the conventional nitrogenase, both, R.capsulatus and A.vinelandii contain alternative nitrogenases. The expression of these alternative nitrogenases is repressed by traces of molybdenum. It was demonstrated that molybdenum transport systems and molybdo-pterin binding proteins are involved in this regulation. (orig.)SIGLEAvailable from TIB Hannover: D.Dt.F.QN1(14,7) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Diversitaet und Gentransfer in denitrifizierenden Bakteriengemeinschaften. Teilprojekt: Analyse des Gentransferpotentials fuer Konjugation und Transformation Abschlussbericht

SIGLEAvailable from TIB Hannover: F00B1241 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Stoffwechselphysiologische Untersuchungen und genetische Optimierung von Aminosaeure produzierenden Mikroorganismen Abschlussbericht

L-amino acids are produced by fermentation for the pharma market, human nutrition and supplementation of feed stuff. In industrial processes predominantly the gram+ species Corynebacterium is used, especially Corynebacterium glutamicum. The project's target was (i) the development of efficient genetechnological methods for Corynebacterium, (ii) the analysis of lysine transport through the membrane and of the biosynthesis of the aspartate-amino acids and (iii) the optimization of a lysine production strain by gene technology. Two different methods for transformation have been developed. By new insertion- and transposon-vectors genes can be inserted into the chromosome. This allows overexpression in strains free of plasmids. Lysine export was analyzed as a carrier dependent transport. The transport system of production strains shows an increased activity. Within the lysine-specific biosynthesis two independent pathways are active which both are relevant for lysine overproduction. Moderate overexpression of a biosynthesis gene in a production strain resulted in a lower synthesis of side-products and significant enhancement of yield and endconcentration. (orig.)SIGLEAvailable from TIB Hannover: F95B359+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Naturstoffe und molekularbiologische Testsysteme. Phase 1 Abschlussbericht

Available from TIB Hannover: F98B1134+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman