Effect of OHL on β-galactosidase activity in K56-I2 Tn 5 -OT182 mutants. A: Growth curves for strains shown in panels B-H. (●) CLW101; (▲) K56-I2-P1; (▼) K56-I2-P3; (□) K56-I2-P9; (◊) K56-I2-P10; (■) K56-I2-P12; (○) K56-I2-NB12; and (*) K56-I2-2PB2. Panels B-H: β-galactosidase activity with (■) and without (□) OHL. Fifty μl of OHL obtained from extracts from a 50 ml culture purified by FPLC and resuspended in 1 ml were added to 10 ml broth. This volume of OHL was shown to restore cepI expression to maximum levels. B: CLW101, C: K56-I2-P1, D: K56-I2-P10, E: K56-I2-P12, F: K56-I2-NB12, G: K56-I2-P9 and H: K56-I2-2PB2.