Use of INAA to study Se, Sb, Zn and Co levels of yeast cells.

Yeast cells, Saccharomyces cerevisiae, were exposed to Sb(V)(10-5M) and SeO2(10-4M) or seleno-cystine (CySe)2(5 x 10-5M). Se, Sb, Zn and Co levels of the yeast were measured by instrumental neutron activation analysis. The results obtained show that in the absence of Se, Sb is taken up by the cells and the highest concentration of Sb in the yeast was observed during the initial 2.5 h of incubation. Both Se-compounds resulted, in general, in a minute decrease of uptake yield of Sb by the cells. This effect can be particularly observed in the presence of SeO2. The presence of Sb in the yeast medium slightly increased the Se level only after long incubation times. Se uptake by the yeast was higher (regardless of Sb dosage) when the yeast was incubated in the medium containing (CySe)2 (in comparison with SeO2). The presence of Se-compounds and/or Sb caused decrease in the levels of Zn found in the cells. While SeO2 presence resulted in minor changes of the Co level of the yeast, the combined presence of Sb and Se-compounds produced the significant enhancement of Co abundance. The similar effect was noted in the yeast incubated in a medium containing only (CySe)2 or Sb.