FIG 3.
Effect of B. cereus ATCC 14579 supernatant (Bc-SN) on Vero cell viability in the presence or absence of B. clausii O/C supernatant (OC-SN). Different times of coincubation between Bc-SN and OC-SN were tested before incubation with Vero cells (15 min, 30 min, and 2 h). Bars represent the percentage of cell attachment (A) or mitochondrial dehydrogenase activity (B) of cells coincubated with Bc-SN, OC-SN, or Bc-SN/OC-SN with or without protease inhibitors (PMSF and EDTA). Vero cells were also pretreated with OC-SN before incubation with Bc-SN (OC-SN/cells – Bc-SN). The percentage of cell attachment or remaining mitochondrial dehydrogenase activity was calculated as 100 × (A/Ac), where A is the absorbance of treated cells and Ac is the absorbance of untreated control cells. Results were the averages ± SD from 3 independent assays. *, significant differences from the corresponding control (P < 0.05); **, significant differences from the corresponding control (P < 0.01); ϕ, significant differences from the Bc-SN condition (P < 0.01).