Skip to main content
. 2010 Jan 20;31(5):785–793. doi: 10.1093/carcin/bgq014

Fig. 5.

Fig. 5.

Plk1 enhances survival of wt Saccharomyces cerevisiae after Cr(VI) treatment. (A) Transformed yeasts were grown in YEP-raffinose to start culture (∼24 to 48 h) and then cultured overnight in YEPG or YEPD. Cells were then subcultured in fresh YEPD (no Plk1 expression) or YEPG (Plk1 expression) to mid-log phase growth (∼2 × 107 cells/ml). Cultures were incubated for 2 h with the indicated concentration of Cr(VI). After treatment, ∼400 cells were plated onto YEPD or YEPG plates and allowed to grow for 3 days. Colonies were counted and data were expressed as percent survival of control (untreated) cultures. Data are the mean + standard error of three independent experiments. Asterisk indicates statistically significant difference from the respective control at P < 0.05. Plus sign indicates a significant difference between yeast expressing Plk1 and not expressing Plk1 at the specified concentration of Cr(VI) at P < 0.05. (B) Yeast transformants (wt-vector and wt-Plk1) were grown in YEP-raffinose to start culture (∼24 to 48 h) and then cultured overnight in YEPG. Cells were then subcultured in fresh YEPG to mid-log phase growth (∼2 × 107 cells/ml). Cultures were incubated for 2 h with the indicated concentration of Cr(VI). Following treatment, yeasts were washed, counted and plated on synthetic complete agar minus arginine (SC-arg), but containing L-canavanine (60 mg/ml), a toxic analogue of arginine, and were grown at 30°C for 7 days. In parallel, ∼200 cells were grown on normal YEPG to account for plating viability. L-canavanine-resistant colonies were counted and mutation frequency was determined relative to plating viability. Spontaneous mutation frequencies were determined by the method of the median. Data are mean ± standard error of three independent experiments. Asterisk indicates statistically significant difference from the respective untreated control at P < 0.05. Plus sign indicates a significant difference between yeast expressing Plk1 and not expressing Plk1 at the specified concentration of Cr(VI) at P < 0.05.