Bienvenidos a CienciaPR, una red de recursos para todos los interesados en las ciencias y en Puerto Rico.
BS Biology 1979 UPR Mayaguez MS Biology 1981 UPR Mayaguez PhD Molecular and Cell Biology 1993 Penn State Univ Post Doc Institute of Tropical Marine Biotechnology 1994
Current theories of cancer highlight hypoxia in microenvironments where oxidative stress damages DNA and promotes mutagenesis. Our major aim is to evaluate suppression of mutagenesis by sulfhydryl antioxidants N-acetylcysteine (NAC), and alpha-lipoic acid, both of which potentiate glutathione activity, the gold standard of antioxidants. Surprisingly, few antioxidant studies have addressed directly the suppression of mutagenesis. Most rely on end points of survival times, anticarcinogenic activity, or chromosomal damage. We hypothesize that the sulfhydryl antioxidants will prevent mutations induced by hydrogen peroxide and gamma radiation, treatments that mimic endogenous mutagenesis by OH radicals. Mutation frequencies (mf) will be quantitated by measuring mutations in a LacI repressor gene, contained in the chromosome of live transgenic Big Blue mice and its cultured cells. Mutations will be detected because the damaged LacI will not be able to repress the expression of the reporter gene (b-galactosidase) in a bacterial system, rendering the resulting plaque blue. These mf will be compared with those obtained by quantification of 8-oxo-guanine production. Suppression of mutations by antioxidants in live Big Blue mice subjected to gamma radiation will be evaluated by two methods: LacI gene mutations and 8-oxo-guanine production. This work will test the notion that antioxidants can effectively block mutations caused by oxidative damage. In addition, our results will provide a basis for a rational policy on the use of antioxidant supplements in humans, either as an anticancer strategy or for counteracting age-related diseases.
Lay summary: This project will test the idea that certain antioxidants in food and supplements can reduce mutations in the DNA of a live animal. It will test several ways to measure mutations to see if they are comparable, in which case one can chose the easier method. If antioxidants work, they may be used to reduce risk of cancer and other diseases tipical of old age.
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