TABLE 2.
Expression of cnrCBA-lacZ in various AE126 mutant strainsa
| Megaplasmid | In trans | 0 mM Ni2+
|
0.5 mM Ni2+
|
||
|---|---|---|---|---|---|
| β-Galactosidase activityb before induction | Increase in β-galactosidase activityc | β-Galactosidase activity before induction | Increase in β-galactosidase activity | ||
| pMOL28d | Φ(cnrHp-lacZ) | 11.1 ± 3.7 | 0 | 10.8 ± 8.6 | 0 |
| Φ(cnrYp-lacZ) | 6.43 ± 1.49 | 8.76 | 0.06 ± 0.01 | 39 | |
| Φ(cnrCp-lacZ) | 0.87 ± 0.52 | 1.26 | 0 | 15 | |
| pMOL28-2, Φ(cnrCBA-lacZ) | None | 62.2 ± 6.8 | 0 | 64 ± 5 | 86.4 |
| nccYXH | 40.0 ± 4.5 | 0 | 46.1 ± 4.7 | 0 | |
| pMOL28-5e Φ(cnrCBA-lacZ) Ω(cnrHC::pECD581) | None | 121 ± 5 | 0 | 102.6 ± 0.4 | 90.7 |
| pMOL28-3, Φ(cnrCBA-lacZ) ΔcnrYXH | None | 28.1 ± 2.5 | 0 | 26.6 ± 1.0 | 0 |
| cnrYXH | 36.0 ± 5.1 | 0 | 48.5 ± 1.8 | 24.8 | |
| cnrY | 39.9 ± 3.3 | 0 | 33.2 ± 3.3 | 0 | |
| cnrX | 34.6 ± 6.0 | 0 | 36.7 ± 3.7 | 0 | |
| cnrH | 937 ± 106 | 0 | 770 ± 52 | 0 | |
| cnrYX | 31.6 ± 3.6 | 0 | 35.0 ± 4.8 | 0 | |
| cnrYH | 1,650 ± 93 | 0 | 1,590 ± 140 | 0 | |
| cnrXH | 900 ± 195 | 0 | 1,025 ± 320 | 0 | |
| cnrY1(Con) cnrXH | 1,350 ± 60 | 0 | 1,380 ± 97 | 0 | |
| nccYXH | 39.9 ± 4.2 | 0 | 47.9 ± 1.3 | 0 | |
| pMOL28-4, Φ(cnrCBA-lacZ) cnrY1(Con) | None | 1,025 ± 107 | 0 | 1,095 ± 88 | 0 |
| cnrYXH | 63.1 ± 5.9 | 18.4 | 61.3 ± 1.2 | 44.5 | |
| cnrY | 114 ± 4 | 0 | 97 ± 2 | 26.0 | |
| cnrX | 687 ± 53 | 0 | 896 ± 19 | 0 | |
| cnrH | 678 ± 97 | 0 | 785 ± 64 | 0 | |
| cnrYX | 151 ± 9 | 0 | 155 ± 19 | 0 | |
| cnrYH | 1,010 ± 68 | 0 | 1,050 ± 176 | 0 | |
| cnrXH | 1,226 ± 254 | 0 | 1,190 ± 176 | 0 | |
| cnrY1(Con) cnrXH | 1,180 ± 55 | 0 | 1,450 ± 123 | 0 | |
| nccYXH | 53.0 ± 6.3 | 0 | 59.1 ± 5.3 | 0 | |
a
Ni2+ (0.5 or 0 mM) was added to cells of various Ralstonia strains which were growing in the early exponential phase (0 h). The β-galactosidase activity was determined for at least 3 h and plotted against time.
b
Means ± standard deviations. Values are units per milligram (dry weight). If no increase occurred, the mean values of all data points of the respective experiment are given.
c
Values are units per hour per milligram (dry weight).
d
The lacZ gene is under control of a cnr promoter on a pVDZ′2 plasmid complementing in trans.
e
Carries an insertion of pLO2 flanked by the duplicated region at bp 2100 to 2400. This separates cnrYXH from cnrCBA (Fig. 1).