Figure 4.

Resistance of the rpoN mutant to hydrogen peroxide. After treatment with hydrogen peroxide (H₂O₂) for 1 hr, changes in viability were determined by dotting 10 μl of bacterial culture (A) or by plating culture aliquots on MH agar plates to count viable cells (B). The data (A) are representative of three independent experiments with similar results. The % viability (B) is expressed as mean ± standard deviation of three independent experiments. The significance of results was P < 0.05 indicated by an asterisk (Prism software version 5.01; GraphPad Software Inc.).