FIG 4.

BSA binds 3OC12-HSL and its degradation product C12-TA-HSL. 3OC12-HSL, C12-TA-HSL, C4-HSL, PQS, HHQ, or HQNO was added to PBS or PBS–5% BSA at a concentration of 5 μM. After a 3-h incubation the solutions were passed through a 30-kDa column to remove the BSA and any of its ligands. Autoinducers were extracted from the eluates, and their levels were measured using LasR, RhlR, or PQS-based luciferase bioreporter strains as described in Materials and Methods. ***, P < 0.0001 (one-way analysis of variance, Tukey posttest). Experiments were repeated at least three times, with at least three technical replicates.