FIGURE 6.
TcpPC19/51/124S activates virulence gene expression similarly to TcpPWT. (A) V. cholerae ΔtcpP strains containing PBAD-controlled plasmids harboring TcpP or its cysteine mutant derivatives and a PtoxT-lux transcriptional fusion plasmid and PBAD vector control were grown in LB with 0.01% arabinose in the presence or absence of taurocholate acid at 37°C until OD600 ≈ 0.2. Luminescence was measured and reported as light units/OD600. Data are the means ± SD (n = 3). (B) V. choleraeΔtcpP strains containing PBAD-TcpP wild type or cysteine mutant plasmids grown in LB with 0.01% arabinose in the presence of taurocholate acid for 6 h. Cell lysates (0.1 mg) were applied to SDS-PAGE and subjected to Western blotting using an anti-TcpP or anti-TcpA antibody. (C) In vivo competition assay using an infant mouse model. Five-days-old ICR infant mice were inoculated with the mixture of TcpP cysteine mutant and WT at 1:1 ratio. Intestinal homogenates were collected 22 h later, and the ratio of mutant-to-WT bacteria was determined and normalized against input ratios.