A. β-galactosidase activity of the aniA::lacZ and ccp::lacZ fusions. Strains RUG7001 (aniA::lacZ), JCGC201 (ccp::lacZ), and JCGC202 (ccp::lacZ fnr) were grown in liquid culture with or without 5 mM NaNO
. Samples were taken at hourly intervals, β-galactosidase activity measured, and the β-galactosidase activities plotted against optical density at 650 nm. B. Data for the JCGC201 (ccp::lacZ) and JCGC202 (ccp::lacZ fnr) fusions are shown on an expanded scale to illustrate more clearly the effects of FNR and nitrite on ccp expression.