title: Effect of minerals on accumulation of Cs by fungus Saccaromyces cerevisiae.
abstract: The accumulation of Cs by unicellular fungus of Saccharomyces cerevisiae in the presence of minerals has been studied to elucidate the role of microorganisms in the migration of radioactive Cs in the environment. Two different types of experiments were employed: experiments using stable Cs to examine the effect of a carbon source on the accumulation of Cs, and accumulation experiments of radioactive Cs from agar medium containing (137)Cs and zeolite, vermiculite, phlogopite, smectite, mica, or illite as mineral supplements. In the former type of experiments, the Cs-accumulated cells were analyzed by scanning electron microscopy equipped with energy dispersive X-ray analysis (SEM-EDS). In the latter type, the radioactivity in the yeast cells was measured by an autoradiography technique. When a carbon source was present, higher amounts of Cs accumulated in the cells than in the resting condition without a carbon source. Analyses with SEM-EDS showed that no mineral formed on the cell surface. These results indicate that the yeast cells accumulate Cs by adsorption on the cell surface and intracellular accumulation. In the presence of minerals in the agar medium, the radioactivity in the yeast cells was in the order of mica > smectite, illite >> vermiculite, phlogopite, zeolite. This order is inversely correlated to the ratio of the concentration of radioactive Cs between the minerals and the medium solution. These results strongly suggest that the yeast accumulates radioactive Cs competitively with minerals.
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 2-4, Shirakata, Tokai, Ibaraki 319-1195, Japan; Research Institute of Nuclear Engineering, University of Fukui, 1-2-4 Kanawa-cho, Tsuruga, Fukui-shi 914-0055, Japan. Electronic address: ohnuki.toshihiko@jaea.go.jp.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Ohnuki
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 2-4, Shirakata, Tokai, Ibaraki 319-1195, Japan.
authors.forename: Fuminori
authors.initials: F
authors.lastname: Sakamoto
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 2-4, Shirakata, Tokai, Ibaraki 319-1195, Japan; Division of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba-shi, Ibaraki 305-8577, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Yamasaki
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 2-4, Shirakata, Tokai, Ibaraki 319-1195, Japan.
authors.forename: Naofumi
authors.initials: N
authors.lastname: Kozai
authors.affiliation: Department of Chemistry, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka-shi, Fukuoka 812-8581, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shiotsu
authors.affiliation: Department of Chemistry, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka-shi, Fukuoka 812-8581, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Utsunomiya
authors.affiliation: Division of Energy and Environmental Systems, Graduate School of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo Hokkaido 060-8628, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Watanabe
authors.affiliation: Division of Energy and Environmental Systems, Graduate School of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo Hokkaido 060-8628, Japan.
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Kozaki
mesh_terms: D000362:Agar / Q000032:analysis; D002588:Cesium Radioisotopes / Q000378:metabolism*; D003470:Culture Media / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D008903:Minerals / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000378:metabolism*; D013052:Spectrometry, X-Ray Emission
chemical_list: D002588:Cesium Radioisotopes; D003470:Culture Media; D008903:Minerals; D000362:Agar
keywords: Accumulation; Fungi; Migration; Mineral; Radioactive Cs