FIG. 9.

Loss of SbcCD, RpoS, or both does not further reduce the growth-dependent mutation rate of strains lacking RecB. Mutation rates were determined by 36-culture fluctuation tests and were calculated by the MSS maximum-likelihood method; bars show 95% confidence levels (28, 60). All strains carried pPFG96 with Pol IV overexpressed under the control of the araBAD promoter. rpoS::Cm ΔsbcDC/pdinB⁺⁺, PFG991; ΔrecB ΔsbcDC/pdinB⁺⁺, PFG1122; ΔrecB rpoS::Cm/pdinB⁺⁺, PFG1138; ΔrecB rpoS::Cm ΔsbcDC/pdinB⁺⁺, PFG1143.