Figure 4

Expression of ColR is not induced by metal stress. (A) β-galactosidase activities measured in P. putida wild-type PaW85 strain carrying the transcriptional fusion of the colRS operon promoter with lacZ in the plasmid p9TT_BlacZ. Bacteria were grown in LB medium and in LB containing 0.6 mM ZnSO₄ or 0.15 mM FeSO₄. Data (means with 95% confidence intervals) of at least four independent experiments are presented. (B) Western blot showing ColR expression in P. putida wild-type (wt) and colR-deficient strain (colR). Location of ColR is indicated with an arrow. Proteins were extracted from bacteria grown in LB medium and in LB containing 0.6 mM ZnSO₄ or 0.15 mM FeSO₄. All lanes contain 3 μg of total protein extract.