TABLE 5.
Effects of narX, narQ, and pta-ackA genotypes on NarL- and NarP-dependent O1-nrfA repression
| Alleleb | β-Galactosidase activitya |
||||||||
|---|---|---|---|---|---|---|---|---|---|
|
narX+ ΔnarQc |
ΔnarX ΔnarQd |
ΔnarX ΔnarQ Δ(pta-ackA)e |
|||||||
| None | Nitrate | Ratio | None | Nitrate | Ratio | None | Nitrate | Ratio | |
| Vector only | 4,690 | 4,940 | 0.9 | 4,100 | 4,320 | 0.9 | 6,180 | 6,480 | 0.9 |
| narL+ | 3,990 | 240 | 17 | 3,580 | 1,950 | 1.8 | 3,280 | 640 | 5.1 |
| narL (V88A) | —f | — | — | — | — | — | 360 | 340 | 1.0 |
| narP+ | 3,730 | 1,120 | 3.3 | 3,970 | 3,740 | 1.1 | 7,340 | 5,120 | 1.4 |
| narP (V88A) | 620 | 220 | 2.8 | 850 | 470 | 1.8 | 410 | 320 | 1.3 |
a
Activity was measured as described in Materials and Methods and is expressed in Miller units.
b
Missense substitutions in narL† and narP† alleles integrated at attϕ80.
c
Strain VJS12032 [λ(O3-lac O1-nrfA) ΔnarL ΔnarQ ΔnarP pcnB1]. Cultures were grown in complex medium (MGTY) with nitrate added as indicated.
d
Strain VJS12031 [λ(O3-lac O1-nrfA) Δ(narXL) ΔnarQ ΔnarP pcnB1]. Cultures were grown in complex medium (MGTY) with nitrate added as indicated.
e
Strain VJS12421 [λ(O3-lac O1-nrfA) Δ(narXL) ΔnarQ ΔnarP Δ(pta-ackA)]. Cultures were grown in MOPS medium with added tryptone and glucose; nitrate was added as indicated.
f
—, not determined.