Figure 2: Nature Communications

Fig. 2

From: Non-canonical activation of OmpR drives acid and osmotic stress responses in single bacterial cells

Fig. 2

Osmotic stress acidifies S. Typhimurium via OmpR repression of rpoS. a mRNA levels of rpos and ssrA (a positive control) genes were determined by qRT-PCR from wild-type and ompR null strains of S. Typhimurium grown at high osmolality. Fold expression changes in the ompR null strain was compared to the wild-type level and plotted. The error bars represent the mean ± s.d. (n = 6). In the ompR null strain, rpoS transcription was increased, suggesting OmpR repression. b Representative images of R488/440 are shown after 5 and 90 min incubation at pHe 7.2 or pHe 7.2 in the presence of 15% (w/v) sucrose (high osm) of wild type, an ompR/rpoS null strain, an rpoS null strain, and an rpoS over-expressed strain of S. Typhimurium. Scale bar, 3 μm. c A plot from 50 cells of the R488/440 ratios of various mutants of S. Typhimurium at indicated times. Symbols represent the mean ± s.e.m. (n = 3). d An EMSA examined the interaction between OmpR and rpoS. OmpR was incubated with 10 fmol of biotin end-labeled rpoS. Lane 1.7* contained 100-fold excess unlabeled DNA