TABLE 4.

Aerobic and anaerobic regulation of the cka-lacZ fusion^a

Strain	Activity under aerobiosis				Activity under anaerobiosis
	No induction		Induction		No induction		Induction
	OD600	Units	OD600	Units	OD600	Units	OD600	Units
fnr+b	3.83	79	2.91	225	1.59	30	1.48	428
fnrc	4.05	40	2.49	240	0.49	16	0.9	280

^aAfter inoculation, the strains were grown in LB medium aerobically, split into two parts, and further grown aerobically and anaerobically for 1 h, after which they were split again and one part was induced with mitomycin C. β-Galactosidase activity (in Miller units) was assayed 4 h after inoculation. The data represent the average of two independent experiments. 

^bStrain MC4100 with pIK471. 

^cStrain RK5288 with pIK471.