Figure 1. The antimutator role of MazG in Msm (A) and Mtb (B).

Both the bacterial culture conditions and the methods for determination of mutation frequencies were illustrated in Materials and Methods in detail. The frequencies conferring resistance to rifampicin in wild-type (wt), mazG-null (ΔmazG) and the complemented mutant (compl) strains were determined in exponential phase (OD₆₀₀∼0.5) with or without oxidative stress and in the stationary growth phase. Oxidative stress was induced by treating exponential phase cultures with 10 mM H₂O₂ for 5 h (Msm) or 24 h (Mtb). Stationary phase was at the 5^th-day or 28^th-day of culture for Msm or Mtb, respectively. (C) Survival rate of Msm and Mtb strains after exposure to H₂O₂. The numbers shown are mean ± S.E. of 3 independent experiments totaling 15 cultures of Msm and 6 of Mtb.