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Title: The detection and identification of benzo[a]pyrene induced DNA adducts in aquatic species
Author: Morse, H. R.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1995
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Polycyclic aromatic hydrocarbons are ubiquitous pollutants and of these, benzo[a]pyrene (B[a]P) is the most widely characterised. B[a]P exerts its effects by the covalent binding of its metabolites to DNA. It has been well documented that the developmental stages of young organisms are highly susceptible to the effects of such pollutants. Presented here is a study on the effect or developmental stage in Xenopus laevis on the metabolism and subsequent adduct induction and repair. DNA adducts were measured by 32P - postlabelling. Larvae were exposed at various stages of development, to waterborne B[a]P for 24 hours and allowed to recover for up to 6 days. A dose response of total adducts was seen at all stages studied. An increase in different adduct types was also observed with increasing liver development. Repair was biphasic, with adducts persisting for at least 6 days post exposure. Adducts were identified by the use of isomeric standards. The trans (+) anti B[a]PDE-N2-guanine adduct was detected in all stages and this adduct was shown to be non-repairable at stage 50. Larvae at stage 38 were shown to be the most sensitive to the effects of B[a]P, exhibiting signs of cyclopia and teratogenic effects to the forearms, up to 5 days post exposure. Young Xenopus laevis frogs exposed to B[a]P for 24 hours, were analysed for adducts in the liver, heart, pancreas, lungs, kidneys, brain, testes and ovaries. Adducts were detected in all organs except testes and ovaries, the greatest damage being observed in the liver and lungs. Adduct levels in the brain were close to the limit of detection. B[a]P-DNA adducts were examined in Scophthalmus maximus (turbot) a benthic marine organism, as a comparative species to Xenopus. Adduct profiles were different to those observed in Xenopus.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available