Fig. 4

Change in the relative expression of kimA and kup in E. faecalis JH2-2 induced by the presence of NaCl. (a and c) Bacterial cultures were grown to the exponential phase at an initial pH of 9.0 in LBG, LBG 3% NaCl, mLBG or mLBG 3% NaCl. Transcriptional fusion activity was assessed by quantifying mCherry fluorescence in E. faecalis JH2-2 cells transformed with pKimA. Specific fluorescence was calculated as the ratio between the normalized fluorescence detected and the estimated bacterial biomass, determined from the OD₆₀₀ of the exponential culture. The mean values from at least three independent experiments are shown, with error bars representing the standard deviations. Asterisks indicate statistically significant differences determined by the Tukey Multiple Comparison Test (**p < 0.01; ***p < 0.001; **** p < 0.0001). (b and d) Change in the relative expression of kimA and kup in E. faecalis JH2-2 induced by the decrease in K⁺ in the medium and the presence of NaCl. The average values, normalized to the gyrA gene, from at least three independent experiments are shown. The error bars represent the standard deviations. Asterisks indicate statistically significant differences determined by the Tukey Multiple Comparison Test (*p < 0.05).