Fig. 3.

Growth curves at (a) 0.1, (b) 1.0 and (c) 21 % O₂. Strains were initially grown in TY liquid under a gas phase with 21 % O₂. At full growth they were subcultured 1 : 200 into 5 ml of TY medium in 60 ml serum vials. As described in Methods, nitrogen and air were added to the headspaces in the vials above the liquid to give the indicated concentrations of oxygen. Growth was followed by measuring the OD₆₀₀. Error bars indicate sd from at least three separate experiments.