Plasmid-mediated biodegradative fate of monohalogenated biphenyls in facultatively anaerobic sediments
The results of these studies have demonstrated that model PCB substrates can be mineralized by indigenous microbial population in contaminated sediments. This catabolic function can be rate limited at the microenvironmental level by physical-chemical processes such as physical partitioning and accumulation. At the biochemical level, this catabolic function is determined by the existence of plasmid borne genes that, under laboratory conditions, can be maintained and expressed in pure or mixed culture. Numerous limitations are encountered in establishing the significance of these biodegradative bacteria and the catabolic plasmids at the environmental level. Relatively little information is available concerning frequencies and stability of the bacteria or the plasmid encoded genes within the community. There is no information on the incompatibility grouping of the isolated plasmid relative to other plasmids maintained within the populations. Such factors will influence the development of gene screening techniques to monitor gene frequency distributions in the sediment community. Although mineralization of 4CBP was observed under moderately reducing conditions, it remains suspect that transient or trace levels of dissolved oxygen may have permitted conventional aerobic metabolism of the substrate. Large deletions of cryptic DNA observed under laboratory conditions may affect bacterial survival and gene maintenance and transfer under environmental conditions. Perhaps the fundamental question is whether the catabolic genes are maintained and expressed within the community rather than whether the host bacterium can survive in the environment.
- Research Organization:
- Department of Microbiology, University of Tennessee, Knoxville
- OSTI ID:
- 7132854
- Journal Information:
- Basic Life Sci.; (United States), Vol. 28
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
HALOGENATED AROMATIC HYDROCARBONS
BIODEGRADATION
ANAEROBIC CONDITIONS
BACTERIA
GENETICS
METABOLISM
PLASMIDS
SEDIMENTS
AROMATICS
BIOLOGY
CELL CONSTITUENTS
CHEMICAL REACTIONS
DECOMPOSITION
MICROORGANISMS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
560302* - Chemicals Metabolism & Toxicology- Microorganisms- (-1987)
510200 - Environment
Terrestrial- Chemicals Monitoring & Transport- (-1989)