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[Tolerance of the yeast Yarrowia lipolytica to oxidative stress]

E N Biriukova, A G Medentsev, A Iu Arinbasarova

    Mikrobiologiia
    |July 29, 2006
    PubMed

    Insights

    Yeast cells adapt to oxidative stress from hydrogen peroxide, menadione, and juglone. Pre-treatment with non-lethal doses enhances resistance by boosting key defense enzymes.

    Area of Science:

    • Microbiology
    • Biochemistry
    • Cell Biology

    Background:

    • Oxidative stress poses a significant threat to cellular function.
    • Yeast, such as Yarrowia lipolytica, possess defense mechanisms against reactive oxygen species.
    • Understanding yeast adaptation to oxidants is crucial for biotechnology and stress response studies.

    Purpose of the Study:

    • To investigate the adaptive response of Yarrowia lipolytica to oxidative stress induced by hydrogen peroxide, menadione, and juglone.
    • To determine the differential resistance of yeast cells in various growth phases to these oxidants.
    • To elucidate the enzymatic changes associated with yeast adaptation to oxidative stress.

    Main Methods:

    • Exposure of Yarrowia lipolytica cultures to varying concentrations of hydrogen peroxide, menadione, and juglone.
    • Comparison of yeast growth inhibition and survival rates between stationary and exponential growth phases.
    • Pre-treatment of logarithmic-phase cells with non-lethal oxidant concentrations followed by challenge with lethal doses.
    • Assay of key antioxidant enzyme activities, including catalase, superoxide dismutase, glucose-6-phosphate dehydrogenase, and glutathione reductase.

    Main Results:

    • Hydrogen peroxide, menadione, and juglone inhibited yeast growth at specific concentrations (120 mM, 0.5 mM, and 0.03 mM, respectively).
    • Stationary-phase yeast cells exhibited greater resistance to oxidants compared to exponential-phase cells.
    • Pre-treatment with non-lethal oxidant concentrations significantly increased yeast resistance to subsequent high oxidant challenges.
    • Adaptation to oxidants correlated with increased activity of catalase, superoxide dismutase, glucose-6-phosphate dehydrogenase, and glutathione reductase.

    Conclusions:

    • Yarrowia lipolytica demonstrates a robust adaptive response to oxidative stress induced by hydrogen peroxide, menadione, and juglone.
    • Cellular resistance to oxidants is influenced by growth phase and can be enhanced through pre-treatment.
    • The observed adaptation is mechanistically linked to the upregulation of critical antioxidant defense enzymes.

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