FIG. 4.
σB induction by ethanol or entry into stationary phase in B. subtilis strains with single RsbR proteins. B. subtilis strains BSJ43 (rsbP::spc SPβ ctc::lacZ) (○), BSH304 (ΔrsbRB2 ΔrsbRC1::ery ΔrsbRD1::spc rsbQ::TnYLB-1 SPβ ctc::lacZ) (+), BSH305 [ΔrsbRA1(Cm) ΔrsbRC1::ery ΔrsbRD1::spc rsbQ::TnYLB-1 SPβ ctc::lacZ] (▵), BSH306 [ΔrsbRA1(Cm) ΔrsbRB1::kan ΔrsbRD1::spc rsbQ::ery SPβ ctc::lacZ] (▪), and BAR343 [ΔrsbRA1(Cm) ΔrsbRB1::kan ΔrsbRC1::ery rsbP::spc SPβ ctc::lacZ] (♦) were grown in LB and either subjected to 4% ethanol (A) or allowed to enter stationary phase (B). Samples were taken at the indicated intervals and assayed for σB-dependent β-galactosidase activity. Ethanol was added at the zero time point in panel A. The entry into stationary phase is indicated by the arrow in panel B.