Production of extracellular nucleic acids by genetically altered bacteria in aquatic-environment microcosms. [Escherichia coli, Pseudomonas aeroginosa, Pseudomonas cepacia, Bradyrhizobium japonicum]
- Univ. of South Florida, St. Petersburg (USA)
The factors which affect the production of extracellular DNA by genetically altered strains of Escherichia coli, Pseudomonas aeruginosa, Pseudomonas cepacia, and Bradyrhizobium japonicum in aquatic environments were investigated. Cellular nucleic acids were labeled in vivo by incubation with ({sup 3}H)thymidine or ({sup 3}H)adenine, and production of extracellular DNA in marine waters, artificial seawater, or minimal salts media was determined by detecting radiolabeled macromolecules in incubation filtrates. The presence or absence of the ambient microbial community had little effect on the production of extracellular DNA. Three of four organisms produced the greatest amounts of extracellular nucleic acids when incubated in low-salinity media (2% artificial seawater) rather than high-salinity media (10 to 50% artificial seawater). The greatest production of extracellular nucleic acids by P. cepacia occurred at pH 7 and 37{degree}C, suggesting that extracellular-DNA production may be a normal physiologic function of the cell. Incubation of labeled P. cepacia cells in water from Bimini Harbor, Bahamas, resulted in labeling of macromolecules of the ambient microbial population. Collectively these results indicate that (i) extracellular-DNA production by genetically altered bacteria released into aquatic environments is more strongly influenced by physicochemical factors than biotic factors, (ii) extracellular-DNA production rates are usually greater for organisms released in freshwater than marine environments, and (iii) ambient microbial populations can readily utilize materials released by these organisms.
- OSTI ID:
- 7018770
- Journal Information:
- Applied and Environmental Microbiology; (USA), Vol. 55:8; ISSN 0099-2240
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BACTERIA
GENETIC ENGINEERING
ENVIRONMENTAL EFFECTS
ADENINES
AQUATIC ECOSYSTEMS
DNA
ESCHERICHIA COLI
MICROCOSMS
PSEUDOMONAS
RHIZOBIUM
THYMIDINE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
AMINES
ANTIMETABOLITES
AROMATICS
AZAARENES
AZINES
DRUGS
ECOSYSTEMS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
MICROORGANISMS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PURINES
PYRIMIDINES
RIBOSIDES
550401* - Genetics- Tracer Techniques