ToxT-dependent TnphoA fusions are modulated by temperature and bile in the absence of ToxR. V. cholerae strains containing a ΔtoxR1 mutation and TnphoA fusions to ToxT-dependent genes and carrying either plasmid pKEK162, which expresses ToxT from the Plac promoter (ToxT +), or the vector pUC118 (ToxT −) were grown as described in Materials and Methods in LB containing 0.3 mM IPTG in the absence (black bars) or presence (hatched bars) of 0.4% bile at 30 or 37°C. The V. cholerae strains used were KKV356 (ctx::TnphoA), KK357 (acfA::TnphoA), KKV358 (acfB::TnphoA), KKV359 (acfC::TnphoA), KKV362 (tcpI::TnphoA), and KKV363 (tagA::TnphoA). Alkaline phosphatase activities are the averages and standard deviations from three samples (note differences in scale).