Table 5.

Inducer-independent expression ofParaB-phoB + andParaB-phoR + fusions

StrainRelevant genotypeaBAP sp act onb:
d-Glucosed-FructoseGlycerol
BW24803 ParaB-phoB +ΔphoB phoR + 0.3 ± 0.00.4 ± 0.00.4 ± 0.0
BW22861 ParaB-phoR + phoB +ΔphoR 26.4 ± 4.947.7 ± 5.158.8 ± 4.4
  • a Strains are ΔcreABCDΔ(ackA pta) ΔaraBAD; complete genotypes are given in Table 1. The ParaB-phoB +fusion is in single copy at att λ; theParaB-phoR + fusion is in single copy at the araCBAD locus.

  • b Cells were assayed after 18 h of growth in 0.06% glucose–, 0.06% fructose–, or 0.1% glycerol–MOPS medium containing 0.1 mM Pi without arabinose. Values are nanomoles of p-nitrophenol made per unit of cell culture optical density at 420 nm (means ± standard deviations). Strains were grown and assayed in triplicate.