Table 2.
Expression of transcriptional nirS-gusA gene fusion in WT and ΔnirS strains under anaerobic and microaerobic conditions with different nitrogen sources
| Addition | β-Glucuronidase activity (U/mg)a |
|||
|---|---|---|---|---|
| Anaerobic cultures |
Microaerobic cultures |
|||
| WT | ΔnirS mutant | WT | ΔnirS mutant | |
| Noneb | NDc | ND | 6.4 ± 1.4 | 10.8 ± 1.7 |
| NaNO2 (0.5 mM) | ND | ND | 51.1 ± 3.3 | 11.9 ± 2.0 |
| NaNO3 (1 mM) | 49.0 ± 4.9 | 16.1 ± 4.1 | ND | ND |
| NaNO3 (4 mM) | 104.2 ± 14.7 | 25.2 ± 1.9 | 171.7 ± 10.3 | 18.6 ± 3.0 |
| NaNO3 (10 mM) | 147.7 ± 25.5 | 20.9 ± 5.9 | 187.8 ± 10.4 | 35.2 ± 2.9 |
a
Values are averages of at least replicate cultures ± standard deviations.
b
There was no nitrate or nitrite added to the medium.
c
ND, not determined; the β-glucuronidase activity was not measured.