Download Selenite-mediated Oxidative Stress Causing Prooxidant Effect in

Selenite-mediated Oxidative Stress Causing Prooxidant Effect in Yeasts Cells
Challenge by Ionizing Radiation
Porto B.A.A.1; Moreira, Costa-Moreira L.1,2; Haddad-Ribeiro F. 1,2 ; Campos, D.
C.1;Meira-Belo, L.C3, Neves M.J.1
1
Lab. Radiobiologia, CNEN/CDTN, Belo Horizonte, Minas Gerais;
Depto. Microbiologia Instituto de Ciências Biológicas, Universidade de Minas Gerais,
Belo Horizonte, Minas Gerais;
3
Lab. Dosimetria Química, CNEN/CDTN, Belo Horizonte, Minas Gerais.
2
Exposure to ionizing radiation can induce changes in cellular macromolecules due to
indirect effects, which occurs after radiolysis of water molecule. This process generates
reactive oxygen species that cause oxidative damage, culminating in oxidative stress.
This oxidative stress occurs in much pathology, included cancer. Scientific reports show
that selenium compounds presents more accentuated oxidant and toxicity effects on
malignant cells than in normal cells. Selenium is considerate as an element that
presents antioxidant properties and can prevent cancer. Our objective was study the
effect of selenium enrichment in yeast cells challenged with ionizing radiation. The cells
was treated with 0.1 mM of sodium selenite (Na2SeO3) previously, after that it were
irradiated with 100, 165, 200 Gy in a 60Co irradiator. The survived cells were detected by
counting the colonies formed on solid medium and also by incubation with phloxine B.
The determination of lipid peroxidation, total sulphydryl residues and free radicals was
done. We used acridine orange, ethidium bromide and DAPI to verify the type of cell
death. The result showed that the presence of selenium had a radio sensitized and
oxidant role on treated cells.
Word Keys: Selenium, yeast, oxidative stress, ionizing radiation
Supported by: CDTN/CNEN.
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