| Popis: |
The aim of this project was to develop predictive models for the impact of environmental pollution on marine invertebrate cellular immune function, through the analysis of the effects of season and selected organic chemicals on Mytilus edulis cellular immunity. In addition, the seasonal variation in Arenicola marina and Asterias rubens cellular immune function was studied to assess the suitability of these species as bioindicators of pollution. To achieve these aims, the blood cells of M. edulis and A. marina were initially classified into 3 and 5 subpopulations, respectively, based on the morphology and differential staining patterns of fixed cells, whereas the coelomocytes of A. rubens were classed as a single population. The phagocytic ability of M. edulis and A. marina blood cells was impaired during periods of spawning and the stability of lysosomal membranes decreased following these periods. Neutral red retention and phagocytosis assays were also employed to investigate the effects of organic chemicals, with known structural properties, on M. edulis cellular immune function, in order to identify structure-activity relationships. The chemicals studied were the amphiphilic cations, chlorpromazine (CP), clozapine (CZ) and chloroquine (CQ), the PAH, phenanthrene (PH) and the nitro-aromatic, methylene green (MG). Chlorpromazine and MG caused the greatest reductions in haemocyte lysosomal membrane integrity and phagocytic ability out of the 5 chemicals studied, which was believed to result, in part, from the inhibition of oxidative phosphorylation, thus limiting ATP available for the lysosomal retention of NR and phagocytosis, and the generation of radicals by CP and MG, which, in turn, may damage cell membranes. Finally, the NR retention and phagocytosis assays, developed in this project, were employed in field studies to compare the cellular immune function of M. edulis and A. marina sampled from 'polluted' and 'unpolluted' sites in South-West Wales. A. marina proved tolerant to oil pollution, presumably due to their ability, like other polychaetes, to metabolise oil hydrocarbons. In contrast, M. edulis cellular immunity was reduced at an industrialised, 'polluted' site compared with an 'unpolluted', rural site, and this trend correlates with tissue hydrocarbon burden. |
