Fig. 3.
Inhibition of toluene-mediated induction of PtodX by o-xylene, o-chlorotoluene, and 1,2,3-TMB. Eleven 25-ml cultures of P. putida DOT-T1E harboring pMIR66 (containing todST) and pMIR77 (containing a PtodX::lacZ fusion) were grown in LB to a turbidity of 0.2 at 660 nm. Then, six cultures were exposed to o-xylene, o-chlorotoluene, or 1,2,3-TMB (asterisk) at 0.3 mM (hatched bars) or 1.5 mM (dotted bars). When the cultures reached a turbidity of 0.5, buffer (control culture), o-xylene, o-chlorotoluene, or 1,2,3-TMB (all at a final concentration of 0.3 mM) was added to four cultures without addition, and 0.3 mM toluene was added to the seven remaining cultures. The β-gal activity was measured 2 h later. Data are the means and corresponding standard errors derived from at least three independent assays, each done in triplicate.