FIG 3.

Albumin inhibits P. aeruginosa QS. (A) P. aeruginosa GFP reporters were grown for 24 h in LB broth with and without 5% BSA, monitored for their level of GFP fluorescence, and normalized to growth (OD₆₀₀). In the presence of BSA, the expression of most P. aeruginosa QS-controlled genes was significantly reduced in comparison to growth in LB alone. Activities of the Las system-regulated exoproducts LasA (B) and LasB (C) and the PQS system-regulated pyocyanin (D) were measured from the supernatants of overnight cultures of PAO1 grown in LB medium with or without 5% BSA. The QS mutant JP2 (PAO1 ΔlasI rhlI) supernatant was utilized as a negative control. *, P < 0.01; **, P < 0.001; ***, P < 0.0001 (one-way analysis of variance, Tukey posttest). Experiments were repeated at least three times, with at least three technical replicates.