Figure 2

Changes in viability and morphology under osmotic stress. (A) Viable cell counts of the rpoN mutant on MH agar pates containing 0.8% NaCl after incubation for 24 hr. Results are expressed as the mean ± standard deviation of three independent experiments. ***: P < 0.001; the significance of results was statistically analyzed by one-way ANOVA analysis of variance with Dunnett test at a 99.9% confidence intervals using Prism software (version 5.01; GraphPad Software Inc.). (B) Electron microphotographs of WT and mutants grown under high osmotic stress conditions (MH agar pates containing 0.8% NaCl). Bacteria were examined by EF-TEM with negative staining with 0.2% uranyl acetate. Each scale bar of the normal and 0.8% NaCl conditions correspond to 0.5 μm and 1 μm, respectively.