Fig 7.

Response of SdiA to AHL and 1 mM indole in E. coli K-12 and S. Typhimurium during standing growth conditions. (A) Expression of the gadW::Tn5-luxCDABE fusion in E. coli K-12 in either the wild-type (AL4001), sdiA mutant (JLD800), tnaA mutant (ME021), or tnaA sdiA double mutant (ME020) background. (B) Expression of the srgE-luxCDABE fusion in S. Typhimurium 14028 or the isogenic sdiA mutant (BA612). Relative light units (light/OD₅₉₀) after 9 h of standing growth are indicated by bars for 1 μM AHL (black), 0.1% ethyl acetate (EA) (white), 1 mM indole (dark gray), and 0.1% dimethylformamide (DMF) (light 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.