Table 1.
Nitrogenase activity of wild-type Anabaena sp. strain PCC 7120, all1711 insertion mutants, and complemented strainsa
| Strain | Genotype | Nitrogenase activity (μmol ethylene [mg Chl]−1 h−1 ± SD) (no. of independent cultures) under indicated condtions |
|
|---|---|---|---|
| Oxic | Anoxic | ||
| PCC 7120 | Wild type | 31.85 ± 2.45 (6) | 36.67 ± 2.10 (6) |
| FQ163 | all1711::Tn5-1063 | 0.12 ± 0.05 (2) | 6.79 ± 1.28 (2) |
| FQ296 | all1711::Tn5-1063 | 0.29 ± 0.13 (3) | 10.75 ± 1.66 (3) |
| FQ880 | all1711::Tn5-1063 | 0.17 ± 0.07 (3) | 13.61 ± 2.21 (3) |
| FQ163-C1 | FQ163 (pRL3161) | 5.03 ± 0.37 (2) | 4.47 ± 0.00 (2) |
| FQ163-C2 | FQ163 (pRL3161, pRL2880) | 2.09 ± 0.49 (2) | 3.91 ± 1.57 (2) |
| FQ163-C3 | FQ163 (pRL3845) | 3.11 ± 2.17 (2) | 4.09 ± 2.87 (2) |
| FQ296-C | FQ296 (pRL3845) | 1.62 ± 0.20 (3) | 2.46 ± 0.21 (3) |
| FQ880-C | FQ880 (pRL3845) | 1.92 ± 0.67 (3) | 4.65 ± 0.90 (3) |
a
Nitrogenase activity was determined by the acetylene reduction assay under oxic or anoxic conditions as described in Materials and Methods. Data represent means and standard deviations of the results obtained, with the numbers of independent cultures indicated in parentheses.