Metallomic approach to mercury and selenium in the muscle tissue of Cichla monoculus (Tucunaré) from the Negro River/Amazonas.

Abstract

The research proposal aims to identify metal binding proteins associated with mercury (Hg) and selenium (Se) in muscle tissue samples from Cichla monoculus (Tucunaré) from the Negro River/Amazonas, using metallomic strategies. To achieve this, initially the Hgtotal an Setotal concentrations in the muscle tissue of the species Cichla monoculus will be determined by grafite furnace atomic absorption spectrometry (GFAAS). After the Hgtotal and Setotal determinations, the molar ratios Hg:Se and Se:Hg will be calculated, as well as the Se values for health benefits (Se HBVs) in the muscle of Cichla monoculus. Experiments to protein fractions separation of muscle tissue by two-dimensional electrophoresis (2D PAGE) will be carried out for subsequent Hgtotal and Setotal mapping in the spots of the muscle proteome fractionated by 2D PAGE. The protein spots associated with Hg and Se will be characterized by liquid chromatography- tandem mass spectrometry (LC - MS/MS). Based on the FASTA sequences of the metal binding proteins, identified as associated with Hg and Se in the protein spots, ontological analysis using the String software will be carried out, and through GO terms (Gene Ontoloy), the metal binding proteins will be classified into three levels: biological process, molecular function and cellular component. The results obtained in the research proposal will serve as a basis for subsequent studies on differential abundance variation of metal binding proteins associated with Hg and Se. The identification of the differential abundance of metal binding proteins will make it possible to obtain parameters in molecular level, which indicate the deleterious effects associated with Hg contamination, as well as the mitigating effect of Se in relation to the toxicity of mercurial species in Amazon fishes. Keywords: Mercury, selenium, metalloproteomics, biomarkers, Amazonian fish, food safety.