DNA Damage and Reactive Nitrogen Species are Barriers to Vibrio cholerae Colonization of the Infant Mouse Intestine
Figure 3
Growth of RNS/ROS mutants under stress.
A. Nitric oxide stress. Exponentially growing cultures of wild type V. cholerae, the ΔhmpA mutant, ΔprxA mutant or ΔprxA ΔhmpA double mutant were grown with or without 1 mM spermine NONOate as a nitric oxide donor. The recovery and growth of each strain was monitored over time. The averages of 3 experiments are shown for each strain. Curves for wild type, ΔhmpA, ΔprxA and ΔprxA ΔhmpA double mutant treated with spermine NONOate are labeled as “+NO” for clarity. All strains grown in LB without spermine NONOate cluster together and are shown on the plot with the label “All strains−NO”. wild type+NO (red), ΔhmpA+NO (green), ΔprxA+NO (blue), ΔprxA ΔhmpA+NO (orange), wild type−NO (black), ΔhmpA−NO (purple), ΔprxA−NO (cyan) and ΔprxA ΔhmpA−NO (yellow). The growth of the ΔprxA, ΔhmpA and ΔhmpA ΔprxA mutant is significantly delayed by NO compared to wild type by 435 min (p<0.05). B. H2O2 sensitivity. Wild type (▪) and katB::Tn (▴), perA::Tn (▾) and ahpC::Tn (♦) mutants were plated on increasing concentrations of hydrogen peroxide. Cfu were determined after overnight growth. The average of 3 experiments is shown. C. Superoxide sensitivity. Wild type (▪) and sodA::Tn (▴), ΔsodB (▾) and sodC::Tn (♦) mutants were plated on agar containing increasing concentration of the superoxide generating compound plumbagin. Cfu were determined after overnight growth. The average of 3 experiments is shown. D. Exponentially growing cultures of wild type, the xth::Tn mutant, Δnfo mutant or xth::Tn Δnfo double mutant were grown with or without 1 mM spermine NONOate as a nitric oxide donor. The recovery and growth of each strain was monitored over time. The averages of 3 experiments are shown for each strain. Curves for wild type, xth::Tn, Δnfo and xth::Tn Δnfo treated with spermine NONOate are labeled as “+NO” for clarity. All strains grown in LB without spermine NONOate cluster together and are shown on the plot with the label “All strains−NO”. wild type+NO (red), xth::Tn+NO (green), Δnfo+NO (blue), xth::Tn Δnfo+NO (orange), wild type−NO (black), xth::Tn−NO (purple), Δnfo−NO (cyan) and xth::Tn Δnfo−NO (yellow). At 750 min the growth delay of the xth::Tn mutant compared to the wild type in NO is significant (p<0.001) while the growth delay of the Δnfo mutant is not.