FIG. 5.

Expression analysis of toxR (VP0820) and rpoS (VP2553) at 1% and 3% NaCl and at pH 7 and pH 5. Vibrio parahaemolyticus RIMD2210633 was grown under the following conditions: (i) LB with 3% NaCl at pH 7, (ii) LB with 3% NaCl at pH 7 plus 30 min at pH 5, (iii) LB with 1% NaCl at pH 7, and (iv) LB with 1% NaCl at pH 7 plus 30 min at pH 5. Cultures were allowed to grow for 4 h prior to extraction of RNA. Bars represent expression ratios of the toxR (A) or rpoS (B) gene relative to its expression levels found in V. parahaemolyticus grown in LB with 3% NaCl at pH 7 as determined by use of qPCR. RNA was extracted on at least two separate occasions for the conditions examined, and qPCR was run in duplicate for each gene. Error bars indicate standard deviations. An unpaired Student t test was used to determine statistical differences between the samples examined. The asterisk denotes expression ratios significantly greater than the ratio for wild-type cells grown in 3% NaCl at pH 7 (P < 0.00001) for toxR (A) or significantly less (P < 0.00001) for rpoS (B).