Figure 7
ColS responds to ferric iron. β-galactosidase activities measured in P. putida wild-type PaW85 strain carrying the transcriptional fusion of the PP0903 promoter with lacZ in the plasmid p9TTBlacZ. Bacteria were grown in LB medium and in LB containing 0.15 mM FeSO4 or 0.075 mM Fe2(SO4)3 with and without 0.5 mM Na-ascorbate. Data (means with 95% confidence intervals) of at least six independent experiments are presented. Asterisks indicate a statistically significant difference (p < 0.05, two-way ANOVA with post-hoc Bonferroni’s multiple comparison test) between values obtained in media containing no Na-ascorbate and media supplemented with Na-ascorbate.