title: The protective effect of selenium inorganic forms against cadmium and silver toxicity in mycelia of Pleurotus ostreatus.
abstract: The effect of two inorganic selenium forms has been investigated in the mycelia of Pleurotus ostreatus exposed to cadmium and silver salts in the shaken cultures. The degree of toxicity was assessed by the determination of malondialdehyde (MDA; a common biomarker of lipid peroxidation). The mycelia were exposed to one element form (up to 5 mg l(-1)) and also to the following combinations: cadmium(II) + selenium(IV); cadmium(II) + selenium(VI); silver(I) + selenium(IV); silver(I) + selenium(VI). The concentrations of cadmium, silver, selenium, and MDA were assessed in the mixed cytosol and cell membrane fractions (CCM). A positive correlation between MDA and cadmium was found in the CCM (beta=0.7775, P=0.0001), whereas the effect of silver was less significant (beta=0.4642, P=0.039). These results indicate that silver(I) and cadmium(II) have different capacities to induce lipid peroxidation in P. ostreatus. The protective role of selenium against metal-induced oxidative damage was found to be dependent on the oxidation state of the element form in the growth medium. The strongest beneficial effect was observed in mycelia exposed to cadmium(II) + selenium(IV) (inverse correlation between MDA and selenium in the CCM: beta=-0.7129, P=0.009) and it has been ascribed to a lower incorporation of the toxic metal and/or to possible intracellular interaction between selenium and cadmium. Under exposure to silver(I), the protective effect of selenium(IV) was less noticeable (correlation between MDA and selenium in the CCM; beta=-0.6068, P=0.036); in the presence of selenium(VI), no beneficial effect was observed.
authors.affiliation: Instituto de Investigaciones Cientificas, Universidad de Guanajuato, L. de Retana 5, 36000 Guanajuato, Gto., Mexico.
authors.forename: Alma Hortensia
authors.initials: AH
authors.lastname: Serafín Muñoz
authors.forename: Kazimierz
authors.initials: K
authors.lastname: Wrobel
authors.forename: J Felix
authors.initials: JF
authors.lastname: Gutierrez Corona
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Wrobel
mesh_terms: D002104:Cadmium / Q000037:antagonists & inhibitors / Q000633:toxicity*; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008315:Malondialdehyde / Q000378:metabolism; D020076:Pleurotus / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D012643:Selenium / Q000737:chemistry / Q000494:pharmacology*; D012834:Silver / Q000037:antagonists & inhibitors / Q000633:toxicity*
chemical_list: D002104:Cadmium; D012834:Silver; D008315:Malondialdehyde; D012643:Selenium