FIG 7.
Sensitivity of sporulating cells to MMS. (A) Killing of B. subtilis wild-type (●), aag (◆), ywqL (▲), and aag ywqL (■) strains by MMS. Cells from all strains were sporulated in liquid DSM and treated with different concentrations of MMS at 4.5 h after the onset of sporulation, and cell viability was determined as described in Materials and Methods. Results are expressed as averages ± SD from at least three independent experiments. (B) Resistance of B. subtilis wild-type (WT), aag, ywqL, and aag ywqL strains after exposure to MMS. Cells from all strains were sporulated in liquid DSM, treated with the LD50 of MMS (calculated from the dose-response curve in panel A for the wild-type strain) at 4.5 h after the onset of sporulation, spot plated, grown, and photographed as described in Materials and Methods.