Date of Award
Doctor of Philosophy
Gerald J. Small
A methodology based on 77 K laser excited fluorescence spectroscopy, fluorescence quenching, fluorescence line narrowing, and spectroscopic-solvent-accessibility evaluation is shown to be a highly selective and sensitive approach for identification of different types of DNA adducts from benzo (a) pyrene diol epoxides. The fluorescence experiments of using DNA analog-double helix poly(oligo)nucleotide adducts yielded consistent results. Based upon model compounds, two anti-BPDE-DNA adducts have been identified by FLNS, trans N[superscript]2-dG and N[superscript]6-dA, which are believed to be of greatly biological-significance in the initiation processes of carcinogenesis.;This study shows that FLNS has sufficient resolution to distinguish the DNA adducts formed from the different BPDE stereoisomers, (+)-, (-)-anti-, and syn-BPDE-DNA adducts. FLNS was successfully applied to characterize the DNA adducts in the liver of English sole exposed to different doses of BaP in vivo. FLNS directly detected for the first time detected a potent carcinogen, (+)-anti-BPDE-DNA adduct, in women's placental samples. Laser-excited fluorescence spectroscopy also revealed several other adducts in the placental DNA samples. The chemical origins of these adducts can be determined arising from three widespread environmental carcinogens: benzo (a) pyrene, benzo (b) fluoranthene, and dibenz (a,h) anthracene. The metabolic activation of BaP in the woman placenta is mainly through the monooxygenation pathway. In addition, this study reveals that the formation of the major adduct resulting from exposure to BaP in humans and fish is closely associated with the interactions of the co-existing carcinogens. The results of this study indicate that these carcinogens experience the same metabolic pathways in fish and in the human body, which may support the hypothesis that bottom-feeding fish species may serve as early warning indicators of carcinogenic hazards to man.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Lu, Peiqi, "Laser excited fluorescence spectroscopic studies of cellular macromolecular damage from chemical carcinogens " (1990). Retrospective Theses and Dissertations. 9399.