Bacterial Genetics in Natural Environments

The release of genetically engineered micro-organisms into the natural environment has great potential for agriculture, but much basic research is still needed, particularly in regard to the possible unforseen consequences and risks posed by the transfer of genetic material from one organism to another. This book presents a survey of current thinking on this important topic, synthesizing the genetic and ecological aspects. Following an overview of some general aspects of the study of genetics in natural environments, such as genetic approaches to gene transfer in microbial communities, factors influencing dissemination of DNA by bacterial conjugation, the interaction of phages with their environment, and factors limiting gene transfer in bacteria, aquatic and terrestrial environments are considered in the contexts of these aspects. Plasmid transfer in the epilithon, genetic transfer in the marine environment and in activated sludge, the factors affecting bacterial survival, and laboratory tested methods for investigating genetic transfer in water systems are discussed with reference to the aquatic environment. Similarly, for the terrestrial environment, plasmid transfer between soil bacteria is followed by a discussion of gene transfer in polluted soils and the rhizosphere, and by consideration of the use of a model system in studying gene transfer among micro-organisms. The role of soil bacteria in risk assessment analysis and the use of wide host range promotors to monitor the fate of recombinant DNA in soil, are examined, as is gene transfer between steptomycetes in soil, since these are important for the maintenance of soil fertility. An examination of the survival of genetically engineered organisms with reference to man-made surfaces and animals completes the discussion.

Part 1 General aspects of studying genetics in nature: genetic approaches to the study of gene transfer in microbial communities; factors influencing the dissemination of DNA by bacterial conjugation; factors limiting gene transfer in bacteria; phage genetics and ecology. Part 2 Aquativ habitats: plasmid transfer in the epilithon; laboratory standerdized biofilms as a tool to investigate genetic transfers in water systems; survival of laboratry anf freshwater bacteria carrying an extrachromosomal xylE gene in freshwater microcosms; gene transfer in marine environments; gene transfer in activated sludge. Part 3 Terrestrial habitats: plasmid transfer between soil bacteria; gene transfer in polluted soils; the potential for gene exchange between rhizosphere bacteria; the use of a Sesbania rostrata microcosm for studying gene transfer among micro-organisms; plasmid transfer to indigenous bacteria in soil and rhizosphere - problems and perspectives; use of wide host range promoters to monitor the fate of recombinant DNA in soil; the role of soil bacteria in risk assessment analysis; gene transfer between streptomycetes in soil; the survival of genetically engineered micro-organisms and bacteria on inanimate surfaces and in animals. Part 4 Conclusions: plasmid transfer and the release of genetically engineered bacteria in nature - a discussion and summary.