Table II.
Properties of Zn uptake. The uptake of Zn in the presence of test compounds is expressed as a percentage ± se of up to 12 replicates of the Zn uptake in the reference situation at 90 s, incubation of vesicles at room temperature (24°C), with 0.5 mm Zn citrate, in the presence of MgATP
| Treatment | Zn Uptake
|
|
|---|---|---|
| Sensitive | Tolerant | |
| % | ||
| Mg-ATP (24°C) | 100 | 100 |
| Mg-ATP (4°C) | 45.5 ± 12.2 | 18.7 ± 3.0 |
| Mg-GTP | 61.4 ± 8.3 | 159.0 ± 13.3 |
| ATP | 18.3 ± 5.5 | 11.7 ± 1.6 |
| Mg-ATP + ortho-vanadate | 42.4 ± 4.6 | 101.0 ± 6.9 |
| Mg-ATP + NH4Cl | 48.0 ± 3.5 | 87.1 ± 12.5 |
| Mg-ATP + gramicidin | 77.9 ± 5.0 | 98.9 ± 36.0 |
| Mg-ATP + NH4Cl + bafilomycin | 58 | 132.7 ± 10.2 |
| Mg-ATP + Triton X-100 | 9.8 ± 7.0 | 22.9 ± 14.8 |
The average net uptake for vesicles in the reference situation was 1.85 ± 0.12 and 3.68 ± 0.73 μmol mg−1 vesicle protein for the sensitive and the tolerant ecotype, respectively. All values were corrected for the amount of Zn measured without the addition of Mg-ATP (0.61 ± 0.03 μmol mg−1 vesicle protein for both ecotypes) prior to the calculation of percentages.