Figure 7

Tryptophan biosynthesis is required for biofilm formation. The effect of the trpE mutation and addition of tryptophan (0.01 mM, 0.1 mM) and indole (0.01 mM, 0.1 mM) on static biofilm growth of ΔtrpE (JH3185) was determined after 24 h of growth in CFA broth at 25°C. The addition of tryptophan and indole significantly (*P = 0.02-0.00003) increased biofilm formation when compared to ΔtrpE grown in CFA alone. The mean absorbance values from four wells are shown and the error bars represent the SD between 4 technical replicates.