FIG 5.

Effects of indole on biofilm formation. Biofilm assays were performed with WT strain JB58 and the indicated isogenic mutant strains in the presence or absence of indole. Crystal violet-stained borosilicate tubes (A) and quantifications of the acetic acid-solubilized dye (B) are shown for the indicated strains after 48 h of static growth in LB medium supplemented with 0 or 0.5 mM indole at room temperature. The stained test tubes are representative of at least three independent experiments, with each assay being performed in triplicate. The absorbance data are presented as means ± the SD for three experiments. Statistical significance was determined using two-way ANOVA (*, P ≤ 0.05 relative to the methanol control).