FIG. 4.

Transcriptional activities of the phcK, phcR, and phcT promoters in C. testosteroni R5 (A), of the phcK and phcR promoters in C. testosteroni R5T (B), and of the phcT promoter in C. testosteroni R5R (C) in response to phenol. The strains were transformed with pRC50Pk, which carries the transcriptional fusion of phcKL::lacZ (circles), pRC50Pr, which carries the transcriptional fusion of phcR::lacZ (squares), pRC50Pt, which carries the transcriptional fusion of phcT::lacZ (triangles), or pRC50 (control vector [solid circles]). The first and second genes of the mPH operon are phcK and phcL, respectively (Fig. 1). At time zero, each stationary-phase culture was transferred to MP medium supplemented with 2 mM phenol. Each value is the mean ± standard error from three or four independent experiments.