| Summary: | A large class of xenobiotic compounds can enter the marine environment as constituents of fuel oils, synthetic dyes, foods and industrial wastes. Some of these compounds may pose long term hazards to aquatic biota because of their mutagenic and carcinogenic activities. The metabolism of such chemicals is of primary concern because these compounds may require metabolic activation and detoxification will determine the hazard posed by exposure to these chemicals. We chose to assess these processes in the edible mussel <i>Mytilus edulis</i> as a model to study the metabolism of such potential toxins. The postmitochondrial fraction from the bay mussel <i>M. edulis</i> was used as an activation system in Salmonella/microsome assay. Three protocols (plate-incorporation, pre-incubation assays and fluctuation tests) were evaluated in order to identify optimal techniques for such studies. The fluctuation tests were known to be more sensitive than the other protocols in the detection of the activity of mussel S9 against a panel of promutagens (Chapter 3). This technique was used to determine the range of metabolic capacities of mussel S9 in the activation of a variety of environmental promutagens. The other part of the thesis involved a study of the mutagenic potency of cigarette smoke particulate matter in the Salmonella/mammalian microsome assay in the presence of rat-liver S9. This work involved the study of some of the factors such as ventilation, which influence mutagenic activity in bacteria and in mammalian cell lines (V79 and XEM2). The results of the study indicate that the tobacco particulate matter (TPM) derived from ultra low tar cigarettes, induce more revertants than that from high tar cigarettes. Finally, the data demonstrate that the mutagenic potency of tobacco particulate matter (TPM) is slightly affected by the ventilation either in bacterial (Salmonella) assay or in mammalian assay (micronucleus test) in V79 and XEM2 cell lines.
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