PQS production by wt P. aeruginosa and the oprL, oprI, and oprF mutants. (A) PQS was extracted from whole cultures and quantified using TLC. The oprF mutant produces ∼4-fold more PQS than wt. (B) Complementation of the P. aeruginosa
oprF mutant with pEX1.8-oprF restores PQS to wt levels. (C) The oprF mutant produces slightly more HHQ than the wt, and complementation of the oprF mutant restores HHQ to wt levels. *, P < 0.02 via two-tailed Student's t test, assuming equal variance (n ≥ 4).