Fig. 3.

Metal extraction from YPD/EDTA. Time-course ICP-MS analysis. Cells were pre-cultured on YPD and transferred to YPD/EDTA. At the indicated time points, aliquots were withdrawn, cell density was determined, the cells were sedimented and their content of magnesium, iron, zinc, copper, manganese and calcium was measured. a Values per OD_{600  nm} unit of cells and (b) the values per culture volume, which allows to judge whether there is net transfer of metal from the medium into the accumulating biomass. c Growth on YPD/Chelex medium. Wild-type and vtc4Δ cells were pre-cultured for 5 h on YPD/EDTA and transferred to YPD/Chelex medium supplemented with the indicated metal to final concentrations that are sufficient to support vigorous continuous growth of non-depleted wild-type cells: 0.25 μM CuSO₄; 1.2 μM FeCl₃; 2.6 μM MnSO₄; 2.5 μM ZnSO₄; 0.9 mM CaCl₂; 4.2 mM MgSO₄. The OD_600nm was measured at the indicated time points after transfer. a–c Results represent mean ± SD of at least three independent experiments. Statistical differences in a were determined using Student’s t test comparing vtc4Δ and wild-type cells at each time point; *p ≤ 0.05; **p ≤ 0.005