FIG. 4.

(A) Expression of the bgl operon in lrhA mutants. Cells carrying the lrhA and hns alleles as indicated were grown and then the β-galactosidase activity was measured, as described for Fig. 2. Each value is the mean + standard deviation from four independent assays. WT, wild type. (B) Effect of overproduction of LrhA on bgl expression. Transformants of the indicated strains with pUSI2 (a control vector) or pTO13 were grown at 37°C to the mid-logarithmic phase in TB medium supplemented with 5 mM β-methyl-d-glucoside, 25 μg of ampicillin per ml, and 100 μM IPTG, and then the β-galactosidase activity was measured as described above.