The Anti-Mutagenic Effect ofFlavone in Bacteria Exposed toUV Radiation.Bethany S. Miracle and Phillip R. Musich, Ph.D.Dept. of Biochemistry and Molecular BiologyJames H. Quillen College of MedicineEast Tennessee State UniversityContact: firstname.lastname@example.org
SkinSkin cancer accounts for almosthalf of all cancers in the U. S.It is estimated that there wereover 10,000 deaths from skincancer in 2005.There are 2 types of skincancer:1. Non-melanoma(NMSC)2. Melanoma(MSC)The majority of the NMSCdiagnosed yearly in the U.S. arerelated to sun exposure.
Melanoma Skin CancerMSC is a cancer that begins in the melanocytes.MSC is the most dangerous of all skin cancers, and it causes themajority of skin cancer deaths.The American Cancer Society estimates that in 2006 there will be 62,190new cases of melanoma in this country. About 7,910 people will die dofthis disease.
Non-melanoma Skin CancerNMSC usually occurs in either basal cells or squamous cells, which arelocated at the base of the outer layer of the skin.Over one million of the NMSC diagnosed yearly in the U.S. are relatedto sun exposure.
SunlightSunlight contains three types of UV radiation: UV-C C (100-290 nm),UV-B B (290-320 nm) and UV-A A (320-400 nm).UV-A A and UV-B B make up the majority of the radiation in the sun thatreaches the earth.UV-C C is almost entirely filtered out by the ozone layer and atmosphericcompounds.Sunscreen is used to protect the skin against the damaging effects ofthe sun.For years, it was thought that only UV-B B rays were harmful, but recentresearch suggests that UV-A A could be just as damaging.Although UV-A’s s effects may take longer to arise; they cause aging,wrinkles, and may play a role in causing melanoma.
PurposeTo compare the toxicity of UV-C, UV-B, and UV-A A radiation onflavone-tolerant (Fla t ) E. coli cells.Flavone is an antioxidant compound found in dark-colored fruits andvegetables.Flavone is an aromatic compound containing a benzene ring, which isable to absorb UV radiation.Hypothesis: Flavone protects cells from UV-C, UV-B, and UV-Aradiation.Flavone 3-DFlavone
MethodsA frozen stock of Fla t E. coli cells were prepared by a previous McNairscholar, Joe Falcone.UV damage was tested by measuring cell viability as the ability to forma colony on an agar plate.The cells were exposed to UV-C, UV-B, and UV-A A radiation as aliquotsin a black plastic 96-well micro-titer plate.The number of colonies present in each track dilution of untreated ed cellswere compared to the number of colonies present with increased UV Uexposure times.
MethodsFor UV-B, the cells were irradiated with a UV-B B lamp for the specifiedtimes at a distance of 21 cm. The incident intensity of UV-B B light is12.53 J/cm 2 /s.For UV-C, the cells were irradiated with a UV-C C lamp for the specifiedtimes at a distance of 100 cm. The incident intensity of UV-C C light is1.0 J/cm 2 /s.For UV-A, the cells were irradiated with a UV-A A lamp for the specifiedtimes at a distance of 13.97 cm. The incident intensity of UV-A A light is96.0 J/cm 2 /s.After UV exposure, 10 µl aliquots of each cell sample were tracked ontoLB-agar plates.The plates were then placed in the 37°C incubator for approximately 10-12 hours.
ResultsCell Survival (%)160140120100806040200Fla t vs. Fla NS cells + UV-C Radiationy = -1.0031x + 123.86R 2 = 0.9278y = -1.6799x + 114.16R 2 = 0.87860 20 40 60 80 100Incident Energy (J/cm 2 /s)The UV-C killing is significantly greater for Fla NS cells than for Fla tcells (P < 0.05).
ResultsCell Survival (%)220.127.116.11.40.20Fla t cells vs. Fla NS cells + UV-By = -0.0912x + 1.1953R 2 = 0.906y = -0.1321x + 1.1745R 2 = 0.96170 36.36 121.2 242.4 363.6 545.4 848.4 1212Incident Energy (J/cm 2 /s)The UV-B B killing is significantly greater for Fla NS cells than for Fla t cells(P < 0.01).
ResultsCell Survival (%)1.051.000.950.900.850.800.75Fla t vs. Fla ns + UV-A Radiationy = -1E-06x + 1.0011R 2 = 0.9976y = -2E-06x + 0.9986R 2 = 0.99910 10000 20000 30000 40000 50000 60000 70000Incident Energy (J/cm 2 /s)Also, the UV-A A killing is greater for Fla NS cells than for Fla t cells.
SignificanceThe data indicates that flavone is able to intercalate into the cell’s DNAand protect it by absorbing UV radiation in all cases.Further research could identify new sunscreen additives in order toprovide better UV protection.So, flavone and other antioxidants are potentially beneficial inpreventing skin cancer.
Conclusions and Future ResearchThe data obtained indicates that flavone does protect against UV-C,UV-B, and UV-A A radiation.The results prove that a diet high in antioxidants truly is beneficial toeveryone’s health.Further research could explain the long term effects of UV-A A radiationand prove that antioxidants are essential to help prevent melanoma ma skincancer.
ReferencesThe American Cancer Society. Retrieved July 05, 2005. http://www.cancer.org/docroot/PED/content/ped_7_1_What_You_Need_To_Know_About_Skin_Cancer.asp?sitesiteArea=&level=.htmlAnklam, E., Wollgast, J. Polyphenols in chocolate: is there a contribution to humanhealth? Food Research International 33 (2000) 449-459459Benchmarks. Simplified agar plate method for quantifying viable bacteria.BioTechniques 23:648-650 650 (Oct 1997) vol. 23. no. 4 (1997)Birt, D.F., Hendrich, S., Wang, W. (2001) Dietary agents in cancer cer prevention:flavonoids and isoflavonoids. Pharmacology and Therapeutics 90 (2001)157-177177Dean, J. Flavone: the molecular and mechanistic study of how a simple flavonoidprotects DNA from oxidative damage. Publisher (Johnson City, TennesseeEast Tennessee State University) 2003Falcone, J. (2004) Flavone’s UV protective ability in skin fibroblasts: blasts: a sunscreeneffect only? East Tennessee State UniversityFalcone, J. (Aug. 2003) UV damage to DNA’s and protection by flavonoids. East Tennessee StateUniversity.Fouad, T. (2002) Retrieved on 19 July 2005. Free radical mechanisms in cancerformation. http://www.thedoctorslounge.net/oncolounge/articles/oxidcar2.htmFritsch, E. F., Maniatis, T., Sambrook, J. Molecular cloning, a laboratory manual, 2ndedition, vol. 3. 1989. Published by Cold Springs Harbor Laboratory, ory, U.S.
AcknowledgementsDr. Phil MusichThe Ronald McNair ProgramMs. MichelleMs. Dinah
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