Figure 6.

Rabbit kidney (RK-13) cells were cocultured with live Bacillus subtilis or killed cells in DMEM without antibiotic for 2 h at 37°C. The medium was removed, and cells were washed three times with PBS containing 1% penicillin–streptomycin solution to kill B. subtilis. RK-13 cells were cultured in DMEM containing 1% penicillin–streptomycin solution for 24 h. Also, 100 μl of the DMEM were plated onto nutrient agar to ensure effective killing of B. subtilis. The fold change represents gene expression of RK-13 cells stimulated with live B. subtilis and killed cells compared to that of controls. Bars represented the means ± SDs of three independent experiments. Mann–Whitney U test was conducted to examine differences. *P < 0.05.