FIG. 2.

Autoregulation of xylR gene expression and xylS gene expression in wild-type P. putida bearing wild-type or xylR-knocked out TOL plasmid. P. putida KT2440(pWW0) and P. putida KT2440(pWWΩXylR) were grown on minimal medium as described in Materials and Methods. Overnight cultures were diluted in duplicate to reach a turbidity of 0.4 at 660 nm and were incubated at 30°C with shaking. Two hours later 5 mM benzyl alcohol was added to one of the cultures, and growth was continued for 2 h at 30°C. After this time samples were withdrawn from both cultures for mRNA analysis as described in Materials and Methods. Two sets of reactions were carried out in parallel with primers to detect mRNAs from Pr promoters and Ps promoters. The resulting cDNAs were run in independent sequencing gels. (A) Pr1 and Pr2 indicate 208- and 180-bp cDNAs, respectively; (B) Ps1 indicates a 208-bp cDNA; (C) Ps2 indicates a 77-bp cDNA.