TABLE 2.
MICs of zinc and cadmium for R. metallidurans strains (megaplasmid-free strain AE104 derivatives) carrying mutations in the genes for P-type ATPasesa
| Bacterial strain and relevant genotype | Complementation in trans | MIC (μM)
|
|
|---|---|---|---|
| Zn2+ | Cd2+ | ||
| Plasmid-free wild-type | |||
| AE104 | None | 300 | 350 |
| AE104 | pVDZ′2 | 300 | 350 |
| AE104 | pVDZ′2::czcCBAD′ | 12,000 | 3,000 |
| AE104 | pVDZ′2::czcCBADRS′ | 12,000 | 3,000 |
| Single deletions | |||
| DN438 (ΔcadA) | None | 250 | 250 |
| DN438 (ΔcadA) | pVDZ′2::czcCBADRS′ | 12,000 | 3,000 |
| DN439 (ΔzntA) | None | 150 | 300 |
| DN439 (ΔzntA) | pVDZ′2::czcCBADRS′ | 12,000 | 3,000 |
| Double mutations | |||
| DN440 (ΔcadA zntA::pLO2) | None | 50 | 1 |
| DN440 (ΔcadA zntA::pLO2) | pVDZ′2 | 50 | 1 |
| DN440 (ΔcadA zntA::pLO2) | pVDZ′2::czcCBAD′ | 12,000 | 50 |
| DN440 (ΔcadA zntA::pLO2) | pVDZ′2::czcCBADRS′ | 12,000 | 50 |
| DN441 (ΔzntA cadA::pLO2) | None | 50 | 1 |
| DN441 (ΔzntA cadA::pLO2) | pVDZ′2 | 50 | 1 |
| DN441 (ΔzntA cadA::pLO2) | pVDZ′2::czcCBADRS′ | 12,000 | 50 |
a
The cells were cultivated on Tris-buffered mineral salts medium containing 2 g of sodium gluconate per liter and increasing concentrations of zinc or cadmium chloride. Growth was examined after 3 days at 30°C. The experiment was done twice with identical results.