Figure 10.

The Δsrf mutants lost the ability to form biofilm. (A) WT formed a thick and wrinkled biofilm, while Δsrf mutants did not. Surfactin did not rescue the biofilm formation of Δsrf mutant in liquid MSgg medium. For biofilm formation, 10 μl of strains (OD₆₀₀ = 1) were added to 1 ml MSgg broth and incubated in a 24-well plate at 30°C for 2 days. The addition of 20 μM of surfactin was to determine if surfactin could rescue biofilm formation. (B) For colony morphology, 3 μl of strains (OD₆₀₀ = 1) were spotted on the center of MSgg solid medium, and then incubated at 30°C for 2 or 4 days. To determine if surfactin could rescue colony morphology, solution of 5 μl containing 10 μg of surfactin was spotted on the center of MSgg solid medium before adding 3 μl of FRY1 (OD₆₀₀ = 1).