Effect of vitamin A treatment on superoxide dismutase-deficient yeast strains.
Vitamin A (Vit A) is widely suggested to be protective against oxidative stress. However, different studies have been demonstrated the pro-oxidant effects of retinoids in several experimental models. In this work, we used the yeast Saccharomyces cerevisiae as a model organism to study the Vit A effects on superoxide dismutase (SOD)-deficient yeast strains. We report here that Vit A (10, 20 and 40 mg/ml) decreases the survival of exponentially growing yeast cells, especially in strains deficient in CuZnSOD (sod1Delta) and CuZnSOD/MnSOD (sod1Deltasod2Delta). We also observed the protective effect of vitamin E against the Vit A-induced toxicity. Possible adaptation effects induced by sub-lethal oxidative stress were monitored by pre-, co- and post-treatment with the oxidative agent paraquat. The enzymatic activities of catalase (CAT) and glutathione peroxidase (GPx), and the total glutathione content were determined after Vit A treatment. Our results showed that CuZnSOD represents an important defence against Vit A-generated oxidative damage. In SOD-deficient strains, the main defence against Vit A-produced reactive oxygen species (ROS) is GPx. However, the induction of GPx activity is not sufficient to prevent the Vit A-induced cell death in these mutants in exponential phase growth.
Departamento de Biofísica, IB/UFRGS, Porto Alegre, RS, Brazil.
Rafael
R
Roehrs
Daniela R J
DR
Freitas
Aoi
A
Masuda
João A P
JA
Henriques
Temenouga N
TN
Guecheva
Ana-Ligia L P
AL
Ramos
Jenifer
J
Saffi
D002374:Catalase / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000172:deficiency* / Q000235:genetics; D014801:Vitamin A / Q000494:pharmacology*; D014815:Vitamins / Q000494:pharmacology*
D005656:Fungal Proteins; D017382:Reactive Oxygen Species; D014815:Vitamins; D014801:Vitamin A; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005978:Glutathione