Table 2.

Anaerobic expression of nrfA-lacZ andnirB-lacZ reporter fusions in batch culture expression in wild-type and narL and narP mutant strains

Relevant phenotypeExpressiona of:
nrfA-lacZnirB-lacZ
NonePlus nitritePlus nitrateNonePlus nitritePlus nitrate
NarL+NarP+ 40320254202,6003,500
NarLNarP+ 353652152102,0603,100
NarL+NarP 60330255504,1703,960
NarLNarP 257025150270205
  • a Cultures were grown anaerobically in glucose minimal medium as described in Materials and Methods. Where indicated, sodium nitrite was added at an initial concentration of 2.5 mM and sodium nitrate was added at 20 mM. Expression is presented in β-galactosidase units, which are expressed as nanomoles of ONPG hydrolyzed per minute per milligram of protein. None, no additive.