Figure 3.
Complementation of cydX mutation. Plasmid-encoded copies of cydB or cydBX, cydXor cydX-FLAG were introduced into cydX and cydB mutants. A plasmid expressing DsRed served as a negative control. (A) Restoration of stationary phase viability was determined as decribed in Figure 2. (B) Sensitivity to 3% Hydrogen peroxide was assayed as described in Figure 2. Significance of differences was analyzed by One-Way ANOVA, with P values for pairwise comparisons with P < 0.05 indicated. (C) Sensitivity to sodium azide plus nickel sulfate was assayed as described in Figure 2. (D) Sensitivity to acid pH. Viability of cultures incubated for 5 h in E-medium adjusted to pH 7.0 or pH 3.5 was assayed as described in the Materials and Methods. Each data point represents results of a single assay that was repeated twice. (E) Survival in J774 mouse macrophages. J774 cells were infected with cydX or cydB mutants containing indicated plasmids. Cells were lysed at 24 and 48 h post-infection. Bacterial CFU were determined by serial dilution and plating on TSA. Data represent the mean of triplicate samples ±SD from a single experiment of three replicates with similar results. Significance of differences was analyzed by One-Way ANOVA, with P values for pairwise comparisons with P < 0.05 indicated. Dotted lines indicate the limit of detection.