Hypermutation-induced in vivo oxidative stress resistance enhances Vibrio cholerae host adaptation
Fig 6
ROS exposure effects on mutation frequency in vivo and in vitro.
A. Mutation rate in vivo. Fecal pellets from wildtype or ΔmutS mutants colonized in NAC- (blue circles) and NAC+ (orange squares) mice were collected and homogenized in LB containing streptomycin. After brief centrifugation, the supernatants were incubated at 37°C shaker for 12 hrs. The cultures were then serial diluted onto LB agar + streptomycin and LB agar + rifampicin and streptomycin. After overnight growth at 37°C, rifampicin resistant colonies were scored. **: Mann-Whitney test P < 0.01; ns: no significance. B. H2O2 effects on mutation rate in vitro. Overnight cultures of wildtype and ΔmutS were inoculated into fresh LB in the presence of indicated concentration of H2O2 and grown at 37°C shaking for 12 hrs. The cultures were then plated on LB agar and LB agar + 50 μg/ml rifampicin. After overnight growth at 37°C, rifampicin resistant colonies were scored. Error bars represent means and SDs from four independent experiments. **: one-way ANOVA P <0.01 (compared to 0 μM H2O2).