Mechanisms of hyperbaric-oxygen inhibition of growth and net biosynthesis of RNA, DNA, protein and lipids in Escherichia coli.
The effects of hyperbaric oxygen at 4.2 atmospheres on growth, induction of stringency and net synthesis of RNA, DNA, protein and lipid by Escherichia coli were evaluated by measuring culture absorbance and incorporation of specific 14C-labelled substrates. Combinations of different bacterial strains, various nutritional conditions and chloramphenicol were used to suppress or allow induction of stringency and to mitigate or enhance other consequences of reported sites of oxygen toxicity. In minimal medium with glucose as the sole organic nutrient, there was almost instantaneous inhibition of net biosynthesis of four major macromolecular constituents: lipid, RNA, DNA and protein. Net lipid biosynthesis primarily failed indirectly due to induction of stringency. Protein net synthesis declined due to induction of stringency and lack of amino acids. RNA net biosynthesis stopped from a direct effect and indirectly via induction of stringency. Net DNA biosynthesis was indirectly primarily impaired.
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John M. Dalton Research Center, University of Missouri, Columbia 65211.
D000399:Air Pressure; D001426:Bacterial Proteins / Q000096:biosynthesis*; D004269:DNA, Bacterial / Q000096:biosynthesis*; D004926:Escherichia coli / Q000254:growth & development* / Q000378:metabolism; D008055:Lipids / Q000096:biosynthesis; D010100:Oxygen / Q000494:pharmacology*; D012329:RNA, Bacterial / Q000096:biosynthesis*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008055:Lipids; D012329:RNA, Bacterial; D010100:Oxygen