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Pau, France

Vacchina V.,UT2A | Moutet M.,Tetrahedron | Yadan J.-C.,Tetrahedron | de Baene F.,Eco Solution | And 2 more authors.
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2010

An analytical method was developed for the simultaneous speciation of selenomethionine (SeMet) and 2-hydroxy-4-methylselenobutanoic acid (NutraSelen®), a new SeMet precursor. The compounds could be baseline resolved by ion-pairing reversed-phase HPLC using ICP MS detection. Detection limits of 1 ng mL-1 (Se content) could be reached. SELM-1 reference material was used to validate the SeMet measurement. Additionally, the quantification of NutraSelen® was validated by standard addition together with checking the Se mass balance. The procedure developed was then applied to the monitoring of the conversion of NutraSelen® into SeMet by yeast. © 2010 Elsevier B.V. All rights reserved. Source

Bucher G.,Institute for Radiological Protection and Nuclear Safety | Mounicou S.,LCABIE | Simon O.,Institute for Radiological Protection and Nuclear Safety | Floriani M.,Institute for Radiological Protection and Nuclear Safety | And 2 more authors.
Chemosphere | Year: 2014

The toxicity of uranium (U) to aquatic organisms depends notably on its compartmentalization in organs, tissues, cells as well as on its distribution among biomolecules. In order to contribute to the understanding of U accumulation and associated toxicity mechanisms in case of waterborne exposure, this study focused on U fate in the gills epithelia, uptake pathway, of the fish model Danio rerio (zebrafish). U distribution among cytosolic biomolecules was investigated after no addition (0μgL-1 (c0) for 3 and 30d), chronic (20μgL-1 (c20) for 30d) and acute (20μgL-1 (c20) and 250μgL-1 (c250) for 3d) exposures to depleted U. Cytosolic U accounted for an average of 24-32% of gills burden for c20 and c250, respectively. Size Exclusion Chromatography (SEC) coupled with Inductively Coupled Plasma-Sector Field Mass Spectrometry (ICP-SFMS) allowed identification of ecotoxicologically relevant U-containing fractions among cytosolic biomolecules as a function of exposure conditions. In c0 and c20 samples, most U (ca.80%) was found in the Low Molecular Weight fraction (LMW, <18kDa), often considered as a detoxifying fraction. In c250 exposed fish, U was equally distributed between LMW (40%) and High Molecular Weight (HMW, 150-670kDa; 40%) fractions, the latter including sensitive metalloproteins. Uranium-biomolecules were co-eluted with endogenous essential metal (Fe, Cu and Zn) species, however, no major influence on their cytosolic concentration and distribution pattern among cytosolic proteins was found. © 2014 Elsevier Ltd. Source

Bucher G.,LCABIE | Bucher G.,Institute for Radiological Protection and Nuclear Safety | Frelon S.,Institute for Radiological Protection and Nuclear Safety | Simon O.,Institute for Radiological Protection and Nuclear Safety | And 2 more authors.
Analytical and Bioanalytical Chemistry | Year: 2014

An off-gel non-denaturing isoelectric focusing (IEF) method was developed to separate uranium-biomolecule complexes from biological samples as a first step in a multidimensional metalloproteomic approach. Analysis of a synthetic uranium-bovine serum albumin complex demonstrated the focusing ability of the liquid-phase IEF method and the preservation of most of the uranium-protein interactions. The developed method was applied to gill cytosol prepared from zebrafish (Danio rerio) exposed to depleted uranium. The results were compared in terms of resolution, recovery, and protein identities with those obtained by in-gel IEF using an immobilized pH gradient gel strip. © 2014 Springer-Verlag Berlin Heidelberg. Source

Tsang C.-N.,University of Hong Kong | Bianga J.,LCABIE | Sun H.,University of Hong Kong | Szpunar J.,LCABIE | And 2 more authors.
Metallomics | Year: 2012

A method that allows partial denaturation of protein ligands in Bi- and Zn-protein complexes, leaving the metal coordination centre intact, was developed. It was based on the reduction of the S-S bridges with tris(2-carboxyl)phosphine followed by derivatization with iodoacetamide. Consequently conditions that allow the separation of Bi- and Zn-protein complexes using SDS electrophoresis were found. The separation efficiency was much higher than that in non-denaturating blue native electrophoresis. The method allowed the detection of seven Bi-binding protein candidates in H. pylori treated with bismuth subcitrate, some of which - fructose-bisphosphate aldolase (33.6 kDa), urease alpha subunit (26.4 kDa), and the 16.8 kDa proteins: 30S ribosomal protein S6 and neutrophil activating protein (NapA) - were bio-induced during the treatment. The method also allowed the monitoring of the changes in the Zn-proteome during treatment of H. pylori with the Bi-drug, which was found to increase the concentration of the Zn-binding proteins with particularly strong expression of the urease, S-adenosylmethionine synthetase and the above 16.8 kDa proteins. © 2012 The Royal Society of Chemistry. Source

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