抄録
Protein expression of Saccharomyces cerevisiae grown in the medium containing 238U (VI) and 233U (VI) was examined by two-dimensional gel electrophoresis. Saccharomyces cerevisiae of BY4743 was grown in yeast nitrogen base medium containing glucose and glycerol 2-phosphate and 238U of 0, 2.0, and 5.0×10-4 M or 233U of 2.5×10-6 M (radioactivity was higher by 350 times than 2.0×10-4 M 238U) and 5.0×10-6 M for 112 h at 30°C. The growth of Saccharomyces cerevisiae was monitored by measuring OD600 at 112 h after the inoculation. Uranium concentrations in the media also were measured by radiometry using a liquid scintillation counter. The growths of the yeast grown in the above media were in the following order: control > 2.5×10-6 M 233U > 2.0×10-4 M 238U > 5.0×10-6 M 233U > 5.0×10-4 M 238U. This result indicated that not only radiological but also chemical effect of U reduced the growth of the yeast. The concentrations of U in the medium containing 238U or 233U decreased, suggesting U accumulation by the yeast cells. The 2-D gel electrophoresis analysis showed the appearance of several spots after exposure to 238U or to 233U but not in the control containing no uranium. These results show that the yeast cells exposed to U express several specific proteins.
