Figure 4

UV sensitivity of S . Typhimurium rec mutants. Log phase cultures of S. Typhimurium were diluted and spread on LB agar. Multiple dilutions were exposed to 254 nm UV in a dark room at each designated dose. Then the plates were wrapped with aluminum foil and placed at 37°C overnight. Surviving fractions were calculated and shown except ΔrecA strains χ9833 and χ9833(pYA5001), for which no survivors were recovered at any UV dose. wt: χ3761; ΔrecF: χ9070; ΔrecJ: χ9072; ΔrecA(RecA⁺): χ9833(pYA5002); ΔrecF(vector): χ9070(pYA5001); ΔrecF(Typhimurium RecF⁺): χ9070(pYA5005); ΔrecF(Typhi RecF⁺): χ9070(pYA5006). Survival of Rec⁺ strains [χ3761, χ9833(pYA5002), χ9070(pYA5005) and χ9070(pYA5006)] was significantly greater than survival of the Rec^- strains [χ9070, χ9072 and χ9070(pYA5001)] at the UV doses indicated (P ≤ 0.002; *).