Table 3.

Activity of the epsI, opsG, andepsR promoters in the presence or absence of EpsR

StrainEpsRaPlasmidsβ-Galacto- sidase activity (Miller Ub)Relative activityc
K60+pGepsI::lacZ + pLAFR3337.31.0
K60+++pGepsI::lacZ + pKL450.40.2
K60+pGL10::lacZ + pLAFR336.50.1
K60+pGopsG::lacZ + pLAFR3533.41.0
K60::epsRΩpGopsG::lacZ + pLAFR3612.91.2
K60+++pGopsG::lacZ + pKL4600.91.1
K60+pGepsR::lacZ + pLAFR3177.81.0
K60::epsRΩpGepsR::lacZ + pLAFR3169.70.9
K60+++pGepsR::lacZ + pKL4157.50.9
  • a +, produced from one copy ofepsR; +++, produced from pKL4; −, not produced.

  • b β-Galactosidase activity is expressed in Miller units (micromoles ofo-nitrophenyl-β-d-galactopyranoside hydrolyzed per minute per milligram of protein [30]). Values shown are the average of two independent trials.

  • c Activity of each promoter in the presence of wild-type levels of EpsR is adjusted to 1.0.