Adaptative response to enhanced basal oxidative damage in sod mutants from Saccharomyces cerevisiae.
We investigated the adaptative response of S. cerevisiae in sod mutants (sod 1 Delta, sod 2 Delta and sod 1 Deltasod 2 Delta) after H(2)O(2) treatment in the stationary phase. sod 2 Delta and sod 1 Deltasod 2 Delta demonstrated the highest levels of GSH in the control, suggesting that pathways which include GSH protect these double mutants against oxidative stress. In addition, sod 1 Delta and sod 1 Deltasod 2 Delta had higher iron levels than the wild-type, independently of H(2)O(2) stress. Fe levels were increased in sod 2 Delta following H(2)O(2) In addition, the sod 2 Delta mutant was more sensitive to H(2)O(2) treatment than the wild-type. These results suggest that sod 2 Delta sensibility may be associated with *OH production by the Fenton reaction. This increased iron demand in the sod 2 Delta mutant may be a reflection of the cells' efforts to reconstitute proteins that are inactivated in conditions of excess superoxide. MDA levels were assayed by HPLC in these mutants. The highest MDA levels could be observed after 10mM H(2)O(2) treatment in the sod 1 Deltasod 2 Delta double mutant. After treatment with a GSH inhibitor, the MDA level was still higher in the same strain. Thus, both direct and indirect GSH pathways are involved in the protection of lipid membranes and proteins in these mutants and may constitute an adaptative response to enhanced basal oxidative damage produced by superoxide.
Manfredini
Vanusa
V
Laboratório de Estresse Oxidativo, Departamento de Biofísica, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500 prédio 43431, Porto Alegre, RS, 91501-970, Brazil.
Duarte Martins
Vanessa
V
Ruaro Peralba
Maria do Carmo
Mdo C
Silveira Benfato
Mara
M
D000222:Adaptation, Physiological / Q000235:genetics / Q000502:physiology; D005978:Glutathione / Q000032:analysis; D007501:Iron / Q000032:analysis; D015227:Lipid Peroxidation; D008315:Malondialdehyde / Q000032:analysis; D009154:Mutation / Q000235:genetics*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism; D000072105:Superoxide Dismutase-1; D013481:Superoxides / Q000378:metabolism; D000099156:Superoxide Dismutase 2
D005978:Glutathione; D007501:Iron; D008315:Malondialdehyde; D029701:Saccharomyces cerevisiae Proteins; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D013481:Superoxides; D000099156:Superoxide Dismutase 2