FIG. 10.

Effect of an rpoS mutation on the expression of the E. chrysanthemi bfr gene. (A) Expression of a transcriptional bfr::uidA fusion in the wild-type strain and the rpoS mutant. Bacterial growth in L broth was assessed by measuring the OD₆₀₀ (filled squares, bfr::uidA mutant; open circles, bfr::uidA rpoS mutant). β-Glucuronidase activity was determined as described in Materials and Methods. Black bars, bfr::uidA mutant; white bars, bfr::uidA rpoS mutant. Experiments were performed in triplicate, and standard deviations are shown. (B) bfd-bfr messenger accumulation in the wild-type (WT) strain and the rpoS mutant. Cells were grown in L medium, and samples were collected during growth. Northern blot analysis was performed as described in Materials and Methods.