Table 2

ToxR/S and TcpP/H activation of toxT

Strainβ-Galactosidase activity (Miller units) after growth in arabinose
0%0.002%0.02%
ΔtcpP ΔtoxR toxT::lacZ21.47  ±  3.9526.16  ±  2.5325.60  ±  2.15
ΔtcpP ΔtoxR toxT::lacZ (pVJ21)39.59  ±  4.8755.11  ±  3.5253.09  ±  2.53
ΔtcpP ΔtoxR toxT::lacZ (PBAD-PH)22.66  ±  6.9520.32  ±  0.76368.22  ±  31.38
ΔtcpP ΔtoxR toxT::lacZ (pBAD-PH, pVJ21)36.94  ±  2.56770.66  ±  50.522,346.27  ±  429.23
  • β-Galactosidase activities are shown for a ΔtcpP ΔtoxR double mutant V. cholerae strain carrying a toxT::lacZ reporter construct in the chromosome with plasmids expressing the toxR and toxS genes constitutively (pVJ21) and/or the tcpP and tcpH genes from an arabinose-inducible promoter (pBAD-PH). Results are mean ± SD.