FIG. 4.
rpoS promoter activities in parent strain P. putida WCS358 and mutant derivatives obtained by using plasmid pRPO220B. All experiments were performed in triplicate, and the means are shown; the standard deviations are not shown and were all within 5% of the values reported. β-Galactosidase activities were determined at various times after a 20-ml LB medium culture was started an inoculum of 1.6 × 108 CFU. The growth curves of all mutants were comparable to the curve obtained for the parent strain, as indicated in each graph. The values for P. putida mutants MKO1 and M17 are shown in the same graph; the darker bars indicate the values for mutant M17. See text for details. β-gal, β-galactosidase; OD600, optical density at 600 nm.