Effect of small antioxidants molecules on the viability of oxidative stress defective yeast
2008
Fetouche, A.
In this work we studied the capacity of seven (7) small antioxidants molecules (Ascorbic Acid, Caffeic Acid, Catechine, Beta-carotene, Quercetine, Tocotrienol (� and y) and Hesperidin) to protect 3 strains of yeast from oxidative stress in the presence of defined concentration of one of the two pro-oxidant H202 or CHP. Two of the strains used have different mutations in their antioxidant machinery �sod1 a strain that is deficient in super oxide dismutase enzyme and a double knockout strain �oye2glr1 defiicient in the same time in old yellow enzyme and glutathione reductase, characterized by a high concentration of oxidized glutathione (GSSG), the third strain used as control was the wild type BY4741. Regarding the results we found that AA showed a big protective effect for all strains, even for the �gsh1 strain which has lacking in endogenous glutathione and need an exogenous concentration of glutathione to grow. Against that, a high concentration of quercetine and beta-carotene showed an inhibitory effect on all strains which have been confirmed by measuring the level of ROS inside the cells. Old yellow enzyme OYE2 and OYE3 has a major role in oxidative stress and the modulation of programmed cell death processes. For this we used cells that have an endogenous carboxy-terminal fusion of the green fluorescent protein (GFP) to the OYE2 or OYE3 gene and we tried the induction of genes with small 5 �M and high concentration 50�M of BC. (GFP fluorescence was quantified by fluorimetry), BC gave the induction of OYE2-GFP in both concentration and Quercetine lead to the super induction of OYE2-GFP. The results showed no change in fluorescence intensity compared to the different doses of quercetine supplemented.
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