FIG. 2.

Sensitivity of clpC or sigB mutants to oxidative stress. (A and B) Cells of the WT (upper left plates), PBM001 (clpC mutant; upper right plates), MB290 (sigB mutant; lower left plates), and MB288 (clpC sigB double mutant; lower right plates) grown for 24 h (in TSB) were plated on TSA. A disk containing 10 μl of hydrogen peroxide at a concentration of either 15% (A), or 30% (B) was placed, and then plates were incubated (37°C, 18 h). (C) Fifty-milliliter cultures of the wild type and the clpC mutant were grown to an OD₆₀₀ of 0.1. The cultures were split, 7.5 mM of hydrogen peroxide was added to one half, and then both halves were incubated (37°C). Shown are OD₆₀₀ values obtained at the indicated time points (▪, WT without H₂O₂; ▴, WT with H₂O₂; •, PBM001 without H₂O₂; ▾, PBM001 with H₂O₂). Shown are representative results of at least two independent experiments.