Figure 1: Nature Communications

Fig. 1

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

Fig. 1

OmpR drives intracellular acidification in response to acid stress. ad S. Typhimurium and E. coli cultures were incubated with 20 µM BCECF for 60 min before imaging. Representative epifluorescence ratio images (R488/440) of emission channel 525 nm upon 488 nm excitation and 440 nm excitation were obtained for wild type, an ompR null mutant, an ompR/cadBA null strain, a cadBA null strain, and a cadBA over-expressed strain of a S. Typhimurium and c E. coli incubated at either acidic pHe (5.6) or neutral pHe (7.2) or at pHe (7.2) plus 15% (w/v) sucrose. Using ImageJ software, ratio images were color coded with blue (ratio = 0.1) to white (ratio = 1). Scale bar, 3 µm. A plot of the intracellular pH of 50 cells of wild type and mutants of b S. Typhimurium and d E. coli at each indicated time point. Error bars represent the mean ± s.e.m. (n = 3). The complete graphs including all strains in b, c are in Supplementary Fig. 2. Repression of the cad operon was not responsible for intracellular acidification during osmotic stress in S. Typhimurium and E. coli