FIG. 6.
Bacitracin resistance in B. licheniformis DSM13 and ATCC 10716. (A) Killing curve experiments for strain DSM13 (left graph) and ATCC 10716 (right graph) in the presence of bacitracin. Both strains were grown in LB medium to mid-logarithmic growth phase, and cell density was monitored throughout by measuring the absorption at 600 nm (designated O.D.600). The culture was split at the time point indicated by the vertical arrow, and individual subcultures were further inoculated in the presence of increasing amounts of bacitracin. The concentrations corresponding to the individual growth curves are indicated in the inset of each graph. (B) Northern blot analysis of ywoA, ytsCD, and bcrABC expression in the presence (+) and absence (−) of bacitracin. D, strain DSM13; A, strain ATCC 10716. See the legend to Fig. 3B and Materials and Methods for further details.