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Evaluation of the Impact of Protein Aggregation on Cellular Oxidative Stress in Yeast
Published on: June 23, 2018
Antioxidant small molecules confer variable protection against oxidative damage in yeast mutants
Foued Amari1, Abdelmadjid Fettouche, Mario Abou Samra
1Department of Natural Products, Mediterranean Agronomic Institute of Chania, P.O. Box 85, Chania 73100, Greece.
Journal of Agricultural and Food Chemistry
|December 4, 2008
Summary
Dietary antioxidants like ascorbic acid and caffeic acid show promise, but their effectiveness depends on cellular antioxidant defenses. Yeast studies reveal that genetic mutations impact how well these compounds protect against oxidative stress.
Area of Science:
- Biochemistry
- Cell Biology
- Nutritional Science
Background:
- Antioxidants are crucial for mitigating cellular damage caused by reactive oxygen species (ROS).
- Pathologic conditions often involve compromised endogenous antioxidant systems.
- Understanding how dietary antioxidants interact with cellular defenses is vital.
Purpose of the Study:
- To evaluate the antioxidant capacity of small molecules in yeast models with deficient antioxidant machinery.
- To investigate the influence of genetic background on the efficacy of dietary antioxidants.
- To assess the impact of antioxidants on reactive oxygen species (ROS) levels, glutathione status, and stress-responsive protein induction.
Main Methods:
- Utilized yeast strains with deficiencies in superoxide dismutase (SOD1), catalase A (CTA1), and Old Yellow enzyme 2/glutathione reductase 1 (OYE2/GLR1).
- Supplemented yeast with ascorbic acid, beta-carotene, caffeic acid, and quercetin.
- Exposed cells to pro-oxidant conditions and monitored growth recovery, ROS levels, glutathione redox state (GSH/GSSG), and stress protein (OYE2, OYE3) induction.
Main Results:
- Ascorbic acid and caffeic acid generally provided protection, while beta-carotene and quercetin showed context-dependent effects, sometimes inhibiting protection or increasing ROS.
- Quercetin significantly altered glutathione levels but failed to maintain reduced glutathione (GSH) under hydrogen peroxide exposure.
- Stress response genes OYE2 and OYE3 were upregulated, with quercetin notably inducing OYE3, which can sensitize cells to programmed cell death (PCD).
Conclusions:
- The efficacy of dietary antioxidants is significantly modulated by the cell's intrinsic antioxidant machinery.
- Genetic mutations affecting antioxidant pathways can alter the protective or detrimental effects of certain compounds.
- Yeast assays provide a valuable model for dissecting the complex interplay between dietary antioxidants and cellular redox homeostasis.
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