Submitted to: Environmental and Molecular Mutagenesis
Publication Type: Abstract Only
Publication Acceptance Date: 10/6/2004
Publication Date: 10/6/2004
Citation: Rundell, M.S., Muellner, M.G., Wagner, E.D., Plewa, M.J., Berhow, M.A., Vaughn, S.F. 2004. Antioxidant treatment and repression of fapy sites in genomic dna. Environmental and Molecular Mutagenesis.
Technical Abstract: Oxidative stress is the imbalance between the generation of oxidants and antioxidant defense systems. Agents of oxidative stress are typically free radicals and include reactive oxygen species, reactive nitrogen species and sulfur-centered radicals. The primary intracellular source of oxygen radicals is leakage associated with the reduction of O2 to water during mitochondrial respiration. The products are singlet oxygen, superoxide radicals, hydrogen peroxide and hydroxyl radical. Radicals target lipids, proteins, nucleic acids and other major biomolecules. Protective species can scavenge radicals, repair damaged biomolecules or stimulate cells to synthesize anti-oxidant enzymes. Oxidative DNA damage is primarily repaired by base excision repair (BER). BER involves specific DNA glycosylases that removes damaged bases by hydrolyzing the N-glycosidic bond. The resulting AP site is processed by hydrolyzing the phosphodiester bond on the 3' side of the AP site which results in strand breaks that can be detected by SCGE. We used a modified FaPy-SCGE assay that incorporates the treatment with the bifunctional BER enzyme formamidopyrimidine (FaPy) glycosylase. The FaPy-SCGE assay can detect oxidized bases recognized by FaPy. We demonstrated that after 72 h exposure to the Corn Distillate Solid Complex and the antioxidants butylated hydroxyanisole and alpha-tocopherol there was a significant reduction in the number of oxidized base lesions recognized by FaPy due to oxidative DNA damage from normal aerobic metabolism. Research funded by C-FAR grant IDACF 01I-2-4, Corn Marketing Board grant and NIH training grant ES07326-04.