Complexation of Eu(III), Pb(II), and U(VI) with a Paramecium glycoprotein: Microbial transformation of heavy elements in the aquatic environment. (April 2018)

• Record Type: Journal Article
• Authors: Kozai, Naofumi; Sakamoto, Fuminori; Tanaka, Kazuya; Ohnuki, Toshihiko; Satoh, Takahiro; Kamiya, Tomihiro; Grambow, Bernd
• Is Part Of: Chemosphere. Volume 196(2018)
• Page Start: 135
• Page End: 144
• Publication Date: 2018-04
• Subjects: Protozoa -- Paramecium -- Europium -- Uranium -- Complex -- Protein -- Micro-PIXE -- SEC -- ICP-MS; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2017.12.154
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: This study investigated the interaction of inorganic aqueous Eu(III), Pb(II), and U(VI) with Paramecium sp., a representative single-celled protozoan that lives in freshwater. Living and prekilled Paramecium cells were tested. The prekilled cells were killed with a fixative. After 24 h exposure of the cells to inorganic aqueous solutions containing Eu(III) or U(VI), analyses by microparticle-induced X-ray emission with a focused beam (<1 μm) did not detect Eu and U in the living cells, whereas Eu and U were detected in the prekilled cells. Size exclusion chromatography coupled with on-line ultraviolet–visible detection and elemental detection by inductively coupled plasma mass spectrometry of the aqueous phases collected after the living cell experiments revealed that a fraction of the Eu, Pb, and U in the aqueous phase bound to a large ( ca . 250 kDa) Paramecium biomolecule and formed a metal-organic complex. The characteristics of the biomolecule were consistent with those of the soluble glycoproteins covering the surfaces of Paramecium cells. These results show that Paramecium cells transform inorganic aqueous Eu, Pb, and U to organic complexes. This paper discusses the relation between this novel complexation and the sorption of these heavy elements on Paramecium cells. Graphical abstract: Image 1 Highlights: Less Eu(III) and U(VI) were sorbed on living Paramecium cells than prekilled cells. Eu and U formed an aqueous complex with a soluble Paramecium glycoprotein. This soluble glycoprotein is the one covering the entire cell surface of Paramecium.