Fig. 3

Effects of various components in the supernatants of V. vulnificus-cultures on the survival of B. vulgatus. A Interaction between colonies of V. vulnificus and B. vulgatus. The resuspensions of the freshly grown cells of V. vulnificus and B. vulgatus were spotted in vicinity on a RCMS agar plate. After 24 h of anaerobic incubation at 37 °C, the growth pattern of each colony was observed. B Survival of B. vulgatus in the presence of cell-free supernatants of V. vulnificus. The cell-free supernatants (spent medium, SM) of V. vulnificus cultured in LBS for 18 h were prepared as described in the “Methods” section. Serially diluted SM with the fresh LBS broth was added to B. vulgatus. After 6 h anaerobic incubation at 37 °C, B. vulgatus CFUs were enumerated as described in Fig. 2C. C Survival of B. vulgatus in the presence of Vibrio spp. and E. coli. B. vulgatus suspensions in M9-minimal medium were mixed with V. parahaemolyticus, V. cholerae, or E. coli at ratios of 1:1 and 1:10 (B. vulgatus to other bacteria), and incubated in a 37 °C anaerobic chamber for 6 h. After 6 h, the CFUs of B. vulgatus were enumerated as described in “Methods.” The P-values for the comparison with the control (B. vulgatus only) are indicated (Student’s t-test; ns, not significant; *0.001 < P < 0.01; **P < 0.001). D Survival of B. vulgatus in the presence of a mutant V. vulnificus producing less cFP. An llcA-defective V. vulnificus, which has been shown to produce significantly lowered amounts of cFP [24], was mixed with B. vulgatus at ratios of 1:1, 1:5, and 1:10 (B. vulgatus:V. vulnificus). B. vulgatus CFUs were enumerated as described in Fig. 2C