Effect of ohr and ohrR deletions on survival and colony morphology. WT, ΔohrR, and Δohr cells were exposed to the identified concentrations of CHP (top row) or H2O2 (middle row) for 15 min, following which 10-fold serial dilutions were spotted on agar plates. The results are representative of those from at least three experiments. The corresponding colony morphologies, captured after ∼72 h, are illustrated at the bottom.