EFFECTS OF OXYGEN ON THE GROWTH OF DESULFOVIBRIO-DESULFURICANS

Desulfovibrio desulfuricans survived exposure to air on the surface of agar plates for at least 48 h. Under continuous culture conditions two effects of low oxygen partial pressures (10-15 mmHg) were noted: (1) a relief of inhibition by H2S; (2) specific inductive responses to oxygen including an increase in cell respiration (two- to threefold) and in levels of cytochrome c (about 20%), and a rise in the activities of NADH oxidase (threefold) and superoxide dismutase (tenfold). At oxygen partial pressures greater than about 15 mmHg, these effects were reversed, growth became progressively inhibited and the cells began to wash out of the system.