Fig 7.

sigS mutants are sensitive to a variety of DNA damage-inducing stresses. The USA300 wild-type (W) and sigS mutant (M) strains, along with a sigS complement strain (C), were analyzed for viability in the presence of DNA damage-inducing stressors. CFU counts were determined both pre- and postexposure, and the survivability was determined. The data are presented as fold change relative to the wild-type strain and are representative of at least three independent experiments that showed less than 10% variability. Shown are exposures of 30 min to 25 mM MMS (A), of 5 min to 150 mM H₂O₂ (B), of 15 min to 5 mM EtBr (C), and to UV at 4,000 μJ per cm² (D). *, P < 0.05 by a Student t test.