- Colonies were counted after one week for the first experiment and five days after the second experiment
- For plates with a significant amount of colonies, we counted four 1 cm^2 quadrants of the plates, averaged them together, and multiplied by the area of the plate
- Created a nearby flame so as to prevent contamination
- Pipetted 100 uL into each plate
- Dipped tongs in ethanol, then burned off ethanol in flame
- Spread yeast solution around plate with tongs
What happens to yeast when its exposed to UV Light?
Methods:
Serial Dilution
Degradation of the cells start after UV exposure (Pyrimidine dimers)
• not seen till after the culture of yeast has grown
DNA reparation: photoreactivation
- • the splitting of pyrimidine dimers by the use of energy from the sunlight.
Explains the brown bag
Created two batches using the same calculations
- First: diluted 10 uL of C1 with 90 uL media to get C2
- Second: diluted 50 uL of C2 with 450 uL media to get C3
- Third: diluted 80 uL of C3 with 720 uL media to get C4
Exposure
Home Remedies for Preventing Sunburn
- Each juice had three dedicated plates
- Zero, five, and ten seconds
- Plates for zero seconds of exposure time were placed directly into the bag
- Plates for five and ten seconds of exposure time had their lids removed and placed above their respective juice
- Placed directly into a paper bag to prevent the photolyase enzyme from repairing the DNA damage
Introduction
There are numerous natural ways to prevent sunburns
- Carrots, tea, aloe, and oil are some of these
All have the ability to reduce the amount of UV exposure
- What is UV radiation?
- What does it do?
- What is our purpose/hypotheses?
- Why?
Blackberry Juice's Benefits
In 2013, Calvo-Castro, et. al, showed that blackberry juice treatments to human skin cell lines in vitro decreased UVB-mediated damage to DNA.
UV LIGHT PROTECTORS: VEGETABLE/FRUIT JUICES
Lime and Aloe proved to be much more effective over time at preventing yeast death due to UV damage
This was the exact opposite of our hypothesis; the pulpy tomato and papaya juices were not as effective at protecting the yeast from UV damage
If using a fruit juice as a sunscreen, lime or aloe juice would be a more effective protectant
- Köpcke W, Krutmann J. Protection from sunburn with beta-Carotene — a meta-analysis. Photochem Photobiol. 2008 Mar-Apr;84(2):284-8. Epub 2007 Dec 15.
- Korac R, Khambholja K. Pharmacogn Rev. 2011 Jul-Dec; 5(10): 164–173.
- Hatzfeld, Jacquez. “Correlation between Degradation, Replication and Repair of Yeast DNA Irradiated by Ultraviolet or y-Rays.” Emory’s Web of Science, 4 September 1972. 29 October 2014. http://ac.els-cdn.com.proxy.library.emory.edu/0005278773903961/1-s2.0-0005278773903961-main.pdf?_tid=343a68b0-5fbf-11e4-8ef7-
- Calvo-Castro, L., Syed, D., Chamcheu, J., Vilela, F., Pérez, A., Vaillant, F., ... Mukhtar, H. (n.d.). Protective Effect of Tropical Highland Blackberry Juice (Schltdl.) Against UVB-Mediated Damage in Human Epidermal Keratinocytes and in a Reconstituted Skin Equivalent Model.Photochemistry and Photobiology, 1199-1207.
Clarisa Hernandez, Eugenia Addie-Noye , Aneel Maini, Patrick Speck