FIG 2.

Disruption of arginine catabolism in Arc mutants. Wild-type strain HSC5 (WT) and the indicated mutant strains were cultured in unsupplemented C medium (Unsupp.) or C medium supplemented with 10 mM arginine (A) or 10 mM citrulline (B). Following 16 h of incubation, growth yields were measured by OD₆₀₀. For details of each strain, consult Table 1. Data are presented as percent growth relative to that of the wild type grown in unsupplemented C medium and are the means and standard deviations from at least three independent experiments. Differences in growth yield between each supplemented culture versus unsupplemented culture were tested for significance using the Mann-Whitney U test (***, P < 0.001). Doubling times were calculated as described in Materials and Methods.