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Kozai, Naofumi; Onuki, Toshihiko; Koka, Masashi; Sato, Takahiro; Kamiya, Tomihiro; Esaka, Fumitaka
no journal, ,
To reveal the role of protozoa in migration of radionuclides in the environment, this study investigated behavior of U(VI) during culture of Paramecium sp. (P. bursaria) in media containing yeast on which U was sorbed. Paramecium was chosen as model protozoa because it is the most well known unicellular protozoa. After the contact of yeast cells with a U (VI) solution, U phosphates formed on yeast cells. P. bursaria cells were cultured with those yeast cells in an inorganic salt solution containing no phosphate. Only 3% of the presorbed U was dissolved from yeast cells into the liquid phases during the culture of Paramecium. As culture time advances, membranous precipitates formed. These membranous precipitates contained undigested and digested yeast cells and dense membranous organic substance filling gaps between those cells. In the membranous precipitates many particles of U phosphates which size and morphology are similar to those observed in the yeast cells were observed. These results suggest that the U immobilization effect of yeast cells was preserved in the prey-predator system
Kozai, Naofumi; Sakamoto, Fuminori; Tanaka, Kazuya; Sato, Takahiro; Kamiya, Tomihiro
no journal, ,
When living Paramecium cells were exposed to a U(VI) aqueous solution, U was hardly detected in the cells, while U was clearly detected in the Paramecium cells that were pre-killed with a fixative before exposure to the U aqueous solution. The U in the liquid phase after the experiment was found to bound to a large soluble glycoprotein to form pseudocolloid. We discuss the relation between these results and the soluble glycoprotein covering the cell surface of Paramecium.