Fig 3.

Biofilm formation in the presence of AHL and indole in other E. coli backgrounds. Biofilm formation of E. coli MG1655 and W3110 or the isogenic sdiA mutants, BA763 and BA760, is shown. Crystal violet absorbance at 600 nm is indicated by bars for 1 μM AHL (black), 0.1% EA (white), 1 mM indole (light gray), and 0.1% DMF (dark gray). All data points are the averages for nine biological replicates, and error bars indicate SEM. Statistical significance in comparison to results with the solvent control is denoted by asterisks representing t test P values: ∗, <0.05; ∗∗, <0.005; ∗∗∗, <0.0005.