FIG. 7.

Expression of the cytolysin by V. vulnificus strains. Bacteria were grown in LB at 37°C after a 1:100 dilution of an overnight culture. Total RNA (5 μg) was extracted from the bacteria harvested at intervals and examined for the transcriptional levels of the vvhA gene by RNA slot blot hybridization (A). Bacterial cell density and the cytolysin activity in the culture supernatant of each strain (n = 3) were determined at the same time (B). The growth curves of all strains were similar and only that of the wild-type strain is shown. N, E. coli total RNA used as a negative control.