Inducer profile of mhp genes. A, E. coli AFMCRAL (mhpR/Pa-lacZ) was grown in LB medium in the presence of 1 mm concentrations of the tested compounds until the cultures reached an A600 of 0.8–1.0. 2HPP, 2-hydroxyphenylpropionic acid; 3HCI, 3-hydroxycinnamic acid; DHCI, 2,3-dihydroxycinnamic acid; 4HPP, 4-hydroxyphenylpropionic acid; 3-methyl-PP, 3-methylphenylpropionic acid; 3-methoxy-PP, 3-methoxyphenylpropionic acid; CI, cinnamic acid; 4HCI, 4-hydroxycinnamic acid; 2HCI, 2-hydroxycinnamic acid; 3NCI, 3-nitrocinnamic acid; 3CLCI, 3-chlorocinnamic acid; 3-methyl-CI, 3-methylcinnamic acid; 3-methoxy-CI, 3-methoxycinnamic acid; 2-carboxy-CI, 2-carboxycinnamic acid; 2HPA, 2-hydroxyphenylacetic acid; 3HPA, 3-hydroxyphenylacetic acid; 4HPA, 4-hydroxyphenylacetic acid; 4FlPA, 4-fluorophenylacetic acid; BA, benzoic acid; 4HBA, 4-hydroxybenzoic acid; HKP, 4-hydroxy-2-ketopentanoic acid. B, E. coli ED1061AL (pPAL) was grown in LB medium at an A600 of 0.8–1.0 in the presence of 1 mm 3HPP or PP. Results of one experiment are shown; values were reproducible in three separate experiments.