FIG 6.
Reduced CEF susceptibility in the sigAG336C mutant is dependent on σB. The sigAG336C allele no longer decreases CEF susceptibility in strains carrying a sigB deletion. Disk diffusion assays were performed on MH agar plates with a filter paper disk containing 50 μg CEF. Three independent experiments were performed for each strain, and one representative experiment is shown. Note that the sigAG336C allele allows weak growth relatively close to the CEF disk, as visualized after overnight growth (upper right, white bars), but the overall diameters of the zones of growth inhibition are larger in the strains carrying the sigAG336C and sigB alleles (right) than in the strains carrying the sigB-null mutant (left). RT, room temperature.