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Antioxidant Attenuation of Yeast Mutagenesis

This study explores the effects of vitamin C, an antioxidant, on the survival rate of yeast cells exposed to UV radiation. Results suggest that vitamin C can positively affect yeast survivorship, highlighting its potential protective role against oxidative stress.

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Antioxidant Attenuation of Yeast Mutagenesis

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  1. Antioxidant Attenuation of Yeast Mutagenesis Peter Chekan Central Catholic High School Pittsburgh

  2. Ultraviolet light • Electromagnetic radiation • Wavelength shorter than that of visible light • Greater energy for wavelength • Sun produces UV-light • Can cause sunburn skin and cancer • Damages DNA

  3. Oxidative stress • UV light can result in oxidation stress • Increases oxidant production in animal cells • Caused by an imbalance between the production of reactive oxygen • Results in cellular degeneration • Could cause cancer • Antioxidants are thought to counter oxidative stress

  4. Antioxidants • Molecules capable of slowing or preventing the oxidation of other molecules • Maybe able to prevent cancer and coronary heart disease • Body produces antioxidants • Obtained through Diet • Vitamin C

  5. Vitamin C • Antioxidant • Enzyme cofactor • Also known as Ascorbic acid • In Oranges, Strawberries, and Grapefruit • The disease Scurvy occurs from lack of Vitamin C

  6. Saccharomyces cerevisiae(Yeast) • Eukaryotic microorganism • Unicellular • 3–4 µm diameter • Used in baking and production of alcoholic beverages • The most studied cellular model in research • Cell cycle is similar to human cells • Comparable DNA replication, recombination, cell division and metabolism

  7. Purpose • Determine if the antioxidant Vitamin C can increase survivorship of UV-stressed cells

  8. Hypothesis Null Hypothesis • The vitamin C concentrations will not significantly affect UV-stressed yeast survivorship rate Alternative • The vitamin C concentrations will significantly affect the yeast survivorship rate

  9. Materials • Proper safety equipment • Water • Spreader bar • Vortex • SDF • UV Safety Glasses • Test tubes • Test tube rack • Micropipettes • Pipette tips • Yeast (Saccharomyces cerevisiae) • YEPD Agar Plates • YEPD Media (0.5% yeast extract, 2% Glucose, 2% Peptone) • Vitamin C • UV Lamp/hood

  10. Procedure • Saccharomyces cerevisiae was grown overnight in sterilized YEPD media. • A sample of the overnight cultures was added to fresh media in a sterile sidearm flask. • The culture of yeast was incubated at 30°C until a density of 50 Klett spectrophotometer units was reached. This represents a cell density of approximately 107 cells per mL. • The culture was diluted in sterile dilution fluid to a concentration of approximately 105 cells per mL.

  11. Procedure Continued • Jhjhjhjhjh • A • DF • d • The following tubes were created • 0.1 mL of each suspension was plated onto YEPD agar plates (50 total plates) • The plates were exposed to assigned durations of UV radiation (0, 15, 30, 45, 60 sec)

  12. Procedure Continued • H • G • F • F • F • F • F • Plates were incubated for 48 hours at room temperature. • Colonies were counted. Each colony was assumed to have arisen from one cell.

  13. 100 uL 100 uL 100 uL 107 cells/mL (yeast) Dilution Procedure 105 cells/mL 103 cells/mL 102 cells

  14. Data

  15. P= 1.22E-15 P<0.05 P=2.04E-07 P=1.21E-08 P<0.05 P<0.05 P>0.05 P<0.05 P<0.05 P<0.05 P<0.05 P<0.05 P>0.05 P<0.05 P<0.05 P<0.05 P<0.05 P<0.05

  16. Dunnetts Test Results

  17. Dunnetts Test Results IfP is < than 0.05 then the results are significant

  18. Interpretations • UV light significantly effected yeast with or without Vit C • Statistical Analyses supports a rejection for 30 sec • Vit C appeared to improve survivorship of UV stressed cells (expect for 30 sec) • No interaction between variables • Definitely an effect of UV light on yeast

  19. Conclusion • The statistical analyses allows a REJECTION (except for 15 sec) of the null hypothesis, indicating that vitamin C can significantly effect the survivorship rate for yeast • The vitamin C alone appeared positively effect yeast survivorship

  20. Limitations/Extensions • Use different concentrations of Vitamin C • Use different types of antioxidants (Lycopene, Vitamin A, Vitamin E) • Expose to varying amounts of UV light • Increase sample size • Synchronize cell plating times more effectively

  21. References • http://en.wikipedia.org/wiki/Ultraviolet • http://en.wikipedia.org/wiki/File:DNA_UV_mutation.gif • http://en.wikipedia.org/wiki/Vitamin_C • http://en.wikipedia.org/wiki/File:Ambersweet_oranges.jpg • http://lpi.oregonstate.edu/infocenter/vitamins/vitaminC/ • http://en.wikipedia.org/wiki/Antioxidant • http://www.nlm.nih.gov/medlineplus/antioxidants.html

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