DNA-Entlassung aus Bakterien, DNA-Ueberdauerung und genetische Transformation im Boden bei Freisetzungssimulierung Abschlussbericht

An overview is given on the basic mechnisms of bacterial gene transfer processes including conjugation, transduction and transformation, and ecological requirements of these processes are discussed. Emphasis is put on investigations in situ and in microcosmos simulating natural habitats. Transfer frequencies have to be considered as being far from negligible. It is likely that the dynamics of gene transfer play a vital part of the population dynamics characteristic of natural ecosystems and that the transfer can include DNA of all species present. Data suggest that DNA adsorbed on soil particles escape the nucleolytic degradation and that adsorbed plasmid DNA and chromosomal DNA fragments are available for transformation of a naturally competent gram-negative soil bacterium. Gene transfer is considered in relation to the safety of releasing genetically engineered microorganisms to the environment. Such consideration have led to the development of biological containment systems which cause a controlled cell death by the regulated expression of genes with cell-killing formations. (WEN)Available from TIB Hannover: F96B431+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman