FIG. 2.

Growth of wild-type and hydrogenase-deficient strains with Fe(III)-citrate as the electron acceptor. (A) Hydrogen-dependent growth of the wild-type and Hya-deficient strains. (B) Hydrogen-dependent growth of the wild-type and Hyb-deficient strains. The experiment was initiated with 2.5% inocula from early-stationary-phase acetate-Fe(III)-citrate-grown cultures. A limiting concentration of acetate (1 mM) was provided as a carbon source. In each panel, wild-type and mutant cultures were inoculated and incubated in parallel. When two transfers are shown, the time of the second transfer (2.5%) is indicated by a vertical arrow. Data are the mean ± standard deviation of triplicate cultures.