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. 2017 Jun 28;8:1145. doi: 10.3389/fmicb.2017.01145

FIGURE 1.

FIGURE 1

Deletion of mtrB has no effect on growth rate but switches on antibacterial activity in Streptomyces venezuelae NRRL B-65442. (A) Growth curves in liquid MYM medium for the wild-type strain (blue), isogenic ΔmtrB mutant (red) and the ΔmtrB mutant with mtrB introduced in trans at the ΦBT1 phage integration site under the control of the mtrAB-lpqB operon promoter (green). The phases of the life cycle are indicated and the colored arrows show the time points at which samples were taken for ChIP-seq experiments. (B) Top panel shows an immunoblot using polyclonal antiserum raised against purified MtrA. Samples were analyzed at 20 h. The lanes contain equal concentrations of total protein from whole cell extracts from the wild-type S. venezuelae NRRL B-65442 strain, the isogenic ΔmtrB mutant and the wild-type expressing mtrA from the high level, constitutive ermE∗ promoter as verified by Bio-Rad protein assay and Coomassie stained SDS PAGE gels (not shown). Bottom panel. Bioassays of the same strains against Bacillus subtilis (Bsu) show that only the S. venezuelae (Sven) ΔmtrB mutant has antibacterial activity.