Joseph H. GaultFebruary 5, 2011

Central Catholic High School

Electromagnetic radiation The wavelength is shorter than that of

visible light The shorter wavelength has greater energy The sun produces UV light Responsible for sunburn and some cancers Alters and damages DNA

Can cause many problems in people, including heat exhaustion, heat stroke, heat cramps, heat rash, etc

These conditions can be cured in a number of ways:◦ Hydration◦ Loose Clothing◦ Skin ointment

Vitamin E

Antioxidant Protects skin from UV damage Minimizes cell damage from free radicals May protect the heart in lower doses Found in leafy green vegetables, olives, and

various nuts and seeds

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

The purpose of this experiment was to determine if the antioxidant Vitamin E can increase the survivorship of heat and UV stressed yeast cells.

The vitamin E concentrations will not significantly affect UV-stressed and heat stressed yeast survivorship.

Test tubes Test tube rack Micropipettes Pipette tips Yeast

(Saccharomyces cerevisiae) YEPD Agar Plates YEPD Media (0.5% yeast, 2% Glucose, 2% Peptone) Vitamin E UV Lamp/hood

Proper safety equipment Water Spreader bar Vortex SDF UV Safety Glasses Thermometer Water Hot Plates Beakers

1. Saccharomyces cerevisiae was grown overnight in sterilized YEPD media.

2. A sample of the overnight cultures was added to fresh media in a sterile sidearm flask.

3. 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.

4. The culture was diluted in sterile dilution fluid to a concentration of approximately 105 cells per mL.

5. The following tubes were created:

6. 0.1 mL of each suspension was plated onto YEPD agar plates (54 total plates).

7. The plates were exposed to UV light for the following time intervals:

a. 0 Secondsb. 30 Secondsc. 60 Seconds

YeastYeast SDFSDF Vit EVit E

0 % Vit E 0.01 mL 9.99 mL 0 mL

0.1% Vit E

0.01 mL 9.989mL 0.1 mL

1% Vit E 0.01mL 8.99 mL 1.0 mL

8. Equivalent tubes were submerged in water baths for fifteen minutes at the following temperatures:

a. 32°Cb. 42°Cc. 52°C

9. 0.1mL of each suspension was plated onto YEPD agar plates (54 total plates)

10. Plates were incubated at room temperature for 48 hours

11. Colonies were counted. Each colony was assumed to have arisen from one cell.

102 cells103

cells/mL

105 cells/mL

107 cells/mL (yeast)

100 uL100 uL

100 uL

Dilution Dilution ProcedurProceduree

0 %

0 Sec 30 Sec 60 Sec

Trial 1 85 28 28

Trial 2 90 24 24

Trial 3 90 27 25

Trial 4 87 23 23

Trial 5 82 29 27

Trial 6 89 26 22

.1 %

0 Sec 30 Sec 60 Sec

Trial 1 80 40 20

Trial 2 84 42 27

Trial 3 82 50 40

Trial 4 82 43 42

Trial 5 87 28 38

Trial 6 86 47 36

1 %

0 Sec 30 Sec 60 Sec

Trial 1 86 64 45

Trial 2 82 67 47

Trial 3 90 64 49

Trial 4 92 60 43

Trial 5 87 48 42

Trial 6 86 62 48

0 %

32° 42° 52°

Trial 1 76 45 32

Trial 2 84 47 30

Trial 3 79 46 28

Trial 4 83 42 24

Trial 5 82 49 36

Trial 6 77 40 37

.1 %

32° 42° 52°

Trial 1 75 56 48

Trial 2 78 64 47

Trial 3 73 68 49

Trial 4 86 63 53

Trial 5 79 65 46

Trial 6 84 67 42

1%

32° 42° 52°

Trial 1 80 77 56

Trial 2 78 75 54

Trial 3 80 73 59

Trial 4 82 79 57

Trial 5 77 72 58

Trial 6 83 81 60

P-Value: 4.78*10-09

P-Value: .097

P-Value: 5.67*10-17

P-Value: 1.40*10-12 P-Value: 3.07*10-12

P-Value: 0.884

There was no significant variance in survival of the control groups treated with vitamin E.

There was a significant variation in survivorship of cells exposed to UV and not treated with vitamin E.

There was significant variation in survivorship of cells exposed to heat and not treated with vitamin E.

There was significant variation in survivorship of cells when exposed to the various temperatures and treated with vitamin E.

The ANOVA indicated significant variation in the survivorship of the yeast colonies.

Therefore, the null hypothesis was rejected. Vitamin E significantly affects yeast

survivorship when exposed to heat and UV stress.

Lag time Use different concentrations of Vitamin E Use different types of antioxidants

(Lycopene, Vitamin A, Vitamin C) Expose to varying amounts of UV light Expose to a wider range of temperatures Increase sample size

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"Vitamin E." Office of Dietary Supplements (ODS). Web. 25 Jan. 2011. <http://ods.od.nih.gov/factsheets/vitamine/>.

"Vitamin E." Wikipedia, the Free Encyclopedia. Web. 25 Jan. 2011. <http://en.wikipedia.org/wiki/Vitamin_E>.

Web. 29 Jan. 2011. <http://www.ncbi.nlm.nih.gov/pubmed/12443690>.

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