Application of micro-PIXE technique to uptake study of cesium by Saccharomyces cerevisiae

Abstract We examined the accumulation and distribution of Cs, and the presence of other elements in yeast ( Saccharomyces cerevisiae ) cells by the micro-PIXE (particle induced X-ray emission) system developed at the TIARA facility, JAERI, and by energy dispersive spectroscopy (EDS) coupled to a scanning electron microscope. The effects of Cs on yeast growth were determined by measuring the optical density at 600 nm. Addition of 1 mM Cs did not have any effect on the growth of the yeast. Micro-PIXE analysis of cells grown in the presence of Cs showed that Cs was uniformly distributed in the cells. Using PIXE, Cs, P, K and Fe can be detected, whereas only P and S can be determined by the EDS. Cells exposed to Cs showed an increase in Cs peak intensity, and decrease in P, K and Fe with time. These results suggest that micro-PIXE is a useful technique to detect low concentration of toxic elements in microorganisms as well as to monitor their changes as function of growth.