TABLE 1.

Regulation of the narK₁K₂GHJI transcription by Anr, Dnr, IHF, and NarL

P. aeruginosa strain (genotype)	Promoter constructc	Gene in transb	β-Galactosidase activity (Miller units)a
			+ O2 + nitrate	+ O2 + nitrite	+ O2	− O2 + nitrate	− O2 + nitrite	− O2 fermentative
PAO1	PnarG1	—	3	4	5	11	10	7
PAO1	PnarG2	—	9	8	6	10	10	8
PAO1	PnarK1	—	11	10	12	720	390	159
PAO6261 (Δanr)	PnarK1	—	6	6	5	8	12	7
PAO6261 (Δanr)	PnarK1	dnr	—	—	—	134	60	53
PAO1	PnarK1	dnr	—	—	—	761	399	329
RM536 (Δdnr)	PnarK1	—	11	10	9	256	195	104
RM536 (Δdnr)	PnarK1	anr	—	—	—	678	161	268
PAO1	PnarK1	anr	—	—	—	846	200	441
PAO1	PnarK1ΔAnr	—	8	6	5	19	16	21
CHA-A2 (ΔihfA)d	PnarK1	—	4	5	5	72	53	37
PAO1	PnarK1ΔIHF	—	8	7	6	299	152	183
PAO9104 (ΔnarL)	PnarK1	—	4	4	5	14	10	22
PAO9104 (ΔnarL)	PnarK1	narL	9	8	10	630	378	126
PAO1	PnarK1ΔNarL1	—	10	9	10	32	33	30
PAO1	PnarK1ΔNarL2	—	11	8	11	147	107	91
PAO1	PnarK1ΔNarL3	—	2	—	—	138	—	—

^aAll values are results of three independent experiments performed in triplicate. Bacterial strains were grown aerobically and anaerobically in LB medium supplemented with 10 mM sodium nitrate or 1 mM sodium nitrite as described previously (7). Arginine fermentation conditions were achieved as outlined previously (21). The β-galactosidase activities are given in Miller units and are calculated as described previously (18). Standard deviations were between 3 and 13% of given values. —, not measured.

^bThe plasmids pHA411 (anr) and pHA541Ω (dnr) provided the anr and dnr genes in trans as described previously (4, 5). Vector without an insert served as background control. —, no gene in trans.

^cDetails for the construction of tested reporter gene fusions and P. aeruginosa mutants will be provided upon request.

^dCHA-A2 is not isogenic to PAO1. Due to the clear cut results obtained with this strain, the data obtained are presented.