β-Galactosidase activities from tcpR-tcpX′-lacZ fusions with different aromatic compounds. C. necator JMP134 tcpR (pPRTCP) was grown until the OD600 was 0.5 and exposed to 0.1 mM aromatic compounds for 3 h. Abbreviations: SUC, succinate; 2,4,6-TBP, 2,4,6-tribromophenol; PCP, pentachlorophenol; TCHBQ, tetrachlorohydroxibenzoquinone; 2,4,5-T, 2,4,5-trichlorophenoxyacetic acid; 2,4,5-TCP, 2,4,5-trichlorophenol; 2,4,6-TCB, 2,4,6-trichlorobenzoate; 2,4,6-TCA, 2,4,6-trichloroanisole; 2,3-DCP, 2,3-dichlorophenol; 4-CP, 4-chlorophenol; and 3-NP, 3-nitrophenol. The insert shows activity of the tcpR-tcpX′-lacZ fusion at different concentrations of 2,4,6-TCP. The values are averages for three independent tests conducted in duplicate.