Cell growth inhibition by methylselenol (MeSeH) precursors. Exponentially growing BY4741 cells in SC medium supplemented with 100 µM methionine were diluted to 0.1 OD600 in the same medium and left to grow for 2 h. At time zero, 0 (), 25 () or 100 µM () of methylselenoglutathione (MeSeSG) (left panel) or dimethyldiselenide (DMDSe) (right panel) were added and cell growth was monitored by measuring the OD600 at various times during 6 h. Data were plotted on a semi-log scale as a function of time. Doubling times of 119 ± 14 (control), 147 ± 16 (25 µM MeSeSG), 192 ± 19 (100 µM MeSeSG), 157 ± 16 (25 µM DMDSe) and 223 ± 24 (100 µM DMDSe) min were calculated by using regression analysis. The results are the mean and range of two experiments.