FIGURE 3.

lmrB gene in S. mutans UA159 was involved in response to oxidative stress. (A) Relative expression level of lmrB under oxidative conditions. lmrB expression was normalized to the levels of 16S rRNA gene, and the fold of expression change was calculated. ^∗Represented that oxidative stress induced the expression of lmrB significantly (p < 0.05). (B) Oxidative stress assays. H₂O₂ sensitivity of S. mutans UA159 strains was determined by measuring the survival rate of S. mutans UA159 cells at different time points. ^∗Represented that the lmrB mutant was more resistant to H₂O₂ killing compared with the wild type and complemented strains (p < 0.05).