Figure 6.

C. thermophilum Ctr3a and Ctr3b mediate cellular Cu and Ag accumulation and Ag toxicity. A, S. cerevisiae ctr1Δctr3Δ cells (strain MPY17) were transformed with plasmids expressing the indicated proteins and grown in liquid YPD medium to mid-log phase before harvest and inductively coupled plasma MS analysis. B, mid-log phase cells from A were grown in the presence of 1 μm AgNO₃ in YPD for 60 min before harvest and ICP-MS analysis. C, cells from A were transferred into a sterile 96-well plate containing the indicated final concentration of AgNO₃ and allowed to grow for 48 h before A₆₀₀ measurements. Error bars, S.E. for biological triplicates as analyzed by paired t tests. *, p ≤ 0.05; **, p ≤ 0.01; ****, p ≤ 0.0001. n.s., not significant.