FIG. 5.

Expression levels of the virulence regulators virF and virB are significantly reduced in the csrA and pfkA mutants. Real-time PCR analysis of virF and virB expression was performed using strains S. flexneri 2457T (WT), AGS120 (csrA), AGS220 (pfkA), and AGS220/pWPfkA (PfkI⁺). Values are normalized to dksA in each sample, and results shown are relative to the value obtained for 2457T. Data presented are the averages of three or more independent experiments, and error bars represent 1 standard deviation. Relative expression was compared to the wild type by using Student's t test. *, P < 0.01.