Effect of las mutation on colony wrinkling. A. Colony morphology of wild-type (WT) and lasR mutant P. aeruginosa strains PA14, PAO1 and ZK after 5 days of growth at the indicated temperature. B. Colony morphology of the ZK wild-type (WT) and lasI mutant in the presence and absence of 10 μM 3OC12-HSL after 5 days at 37°C.