TABLE 1.

Drug resistance of E. coli cells harboring pTrc plasmids carrying putative response regulator ORFs

DrugNo gene (0.01, 0.1, 1)MIC (μg/ml) for strain carrying gene, with indicated IPTG concn (mM)a
evgAbaeRcpxRbdcuR
0.010.110.01, 0.110.010.1, 10.010.11
Erythromycin3.1312.5253.133.133.133.133.133.136.256.25
Kanamycin3.133.133.131.563.133.133.1312.53.133.133.13
Fosfomycin1.56/0.78d1.560.780.781.56/0.78d0.781.560.781.560.780.78
Doxorubicin3.13100253.133.133.133.133.133.133.133.13
Novobiocin0.783.130.780.786.256.250.783.130.783.133.13
Crystal violet0.783.131.560.780.780.780.780.780.780.781.56
Ethidium bromide25505025252512.512.5252525
Rhodamine 6G6.25100253.136.256.256.256.256.256.256.25
Methyl viologen1001005050100100100100100100100
TPP6.2525256.256.256.253.136.256.256.256.25
Benzalkonium3.132512.53.133.133.133.133.133.133.133.13
SDS504005050100100505050100100
Deoxycholate1,250>40,0001,2501,250>40,0001,2501,250>40,0001,25020,00020,000
  • a Values in boldface are larger than values for the control strain KAM3 harboring pTrc99A. IPTG at 0.01, 0.1, or 1 mM was added to the agar plates. pTrcarcA, pTrcatoC, pTrcb2381, pTrcbasR, pTrccheB, pTrccheY, pTrccreB, pTrcglnG, pTrchydG, pTrcphoB, pTrcphoP, pTrcrssB, pTrcuhpA, pTrcuvrY, pTrcyfhA, pTrcygiX, and pTrcylcA did not affect the MICs. The MICs of chloramphenicol, tetracycline, minocycline, nalidixic acid, norfloxacin, enoxacin, rifampin, polymyxin B, acriflavine, and carbonyl cyanide m-chlorophenylhydrazone did not change.

  • b pTrccpxR conferred amikacin resistance (MIC of 1.56 μg/ml for KAM3 versus 6.25 μg/ml for KAM3/pTrccpxR).

  • c The growth of the KAM3 strain carrying pTrcfimZ was inhibited with 1,250 μg of deoxycholate per ml; however, the growth recovered with 10,000 to 40,000 μg/ml.

  • d The fosfomycin MIC for host and baeR cells was 1.56 μg/ml with 0.01 and 1 mM IPTG and 0.78 μg/ml with 0.1 mM IPTG.