Figure 2.

Comparable ability of wild-type and rpoS mutant strains on bacterial growth, motility, and adhesion. (A) To test swarming motility, the fresh cultured bacteria were inoculated by toothpicks on 0.3% semisolid HI agar plates, and incubated at 37°C incubator for 8 h. (B) To test bacteria adhesion, HeLa cells were incubated with V. vulnificus cells at an MOI of 250 for 30 min. The host cells were washed thoroughly and stained with Giemsa solution. The bacterial cells adhered to 90 HeLa cells were counted and calculated as the average number of adhered bacteria per HeLa cell. (C) To test bacterial growth, V. vulnificus wild-type or rpoS mutant bacteria were inoculated into DMEM or the HeLa lysate media (10⁸ CFU/mL) and incubated in a 5% CO₂ incubator at 37°C for 3 h. The V. vulnificus culture suspensions were 10-fold serially diluted with PBS, and the serial dilutions (10 μL) were loaded on HI agar plates overnight. The results represent are means ± SD (vs. V. vulnificus wild-type in free DMEM, ^*P < 0.05, ^***P < 0.001).