Zoology
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Item In vitro metabolism of benzene, toluene, and xylene in rat liver(North Dakota State Univ., Fargo (USA)., 1985) Pathiratne, A.A headspace gas chromatographic method was used to study the metabolism of benzene, toluene, and m-xylene in rat liver. Metabolism of benzene was lower than that of toluene, or m-xylene. Investigating metabolic rates of subcellular fractions, it was found that glutathione and glutathione S-transferase in the cytosol are involved in metabolism of benzene and toluene by microsomes. When both benzene and toluene are present in the incubation medium, they act as inhibitors of each others metabolism. Toluene and m-xylene metabolism were induced by the pretreatment of rats with phenobarbital (75 mg/kg), or 3-methylcholanthrene (25 mg/kg), or Aroclor 1254 (75 mg/kg) for 3 days, whereas benzene metabolism was not induced by all pretreatments. Another series of experiments was conducted to compare the effects of benzene, toluene, and xylene pretreatment on liver metabolism. In vivo metabolism of /sup 14/C-toluene and possible covalent binding of /sup 14/C-toluene to microsomes were also investigated. /sup 14/C-toluene when incubated with liver microsomes in the presence of a NADPH generating system formed benzylalcohol and cresols. Some of the radioactivity was covalently bound preferentially to microsomal proteins. The binding process required cytochrome P-450 dependent mixed function oxidases. This study suggests that toluene is metabolized to several reactive intermediates by liver microsomal enzymes and these metabolites are responsible for the covalent binding to macromolecules which represents a subcellular mechanism by which toluene may express its own in vivo toxicity.Item Role of fishermen in implementing management strategies in the reservoirs of Sri Lanka(Ottawa : International Development Research Centre, 1988) Amarasingha, U. S.The socioeconomics of six fishing communities in four man-made reservoirs of Sri Lanka was studied to investigate the potential contribution of fishermen to effective management. Adopting illegal fishing methods and changing fishing grounds are two of the socioeeonamic indicators of low incane derived fran the fishery. The fishermen in all six fishing communities were willing to comply with any fishery regulation provided the fishermen unanimously agreed to the regulation. This suggests that effective management strategies, which will contribute to increasing the fishermen's income, can be implemented through properly organized extension societies in the reservoirs of Sri Lanka.Item How effective are the stocking strategies for the management of reservoir fisheries in Sri Lanka, Stocking and Introduction of Fish(Fishing News Books, Blackwell Science, 1998) Amarasingha, U. S.Item Inland fisheries of Sri Lanka and strategies for development(Institute of Biology, Sri Lanka, 1995) Amarasinghe, U.S.Item Selectivity patterns in the multi-net gillnet fishery for Cichlid species in Sri Lankan reservoir(Department of Zoology, National University of Singapore, 1992) Amarasinghe, U.S.; de Silva, S.S.Item Studies on the feasibility of using indigenous fish control agents for aquatic macrophytes in Sri Lanka(Asian Fisheries Forum, 1998) Wijeyaratne, M.J.S.; Perera, W.M.D.S.K.Item Trophic interrelationships of exotic and indigenous fish species co-occurring in some reservoirs of Sri Lanka(Asian Fisheries Forum, 1998) Wijeyaratne, M.J.S.; Perera, W.M.D.S.K.Item Extent of the catchment of reservoirs of Sri Lanka: an important aspect in the management of their capture fisheries(Asian Fisheries Forum, 1998) Nissanka, C.; Amarasinghe, U.S.; de Silva, S.S.Item An appeal to redefine stunning in Oreochromis mossambicus (Cichlidae)(Asian Fisheries Forum, 1998) Amarasinghe, U.S.; de Silva, S.S.Item The ecology of a montane grassland in Sri Lanka. VII. Biomass production(Ceylon Journal of Science, Biological Sciences, 1983) Amarasinghe, L.D.; Pemadasa, M.A.Biomass accumulation was studied monthly on 2 montane grasslands in Sri Lanka at 900 m and 560 m alt. from June 1976 to May 1977. The upper site was a dense sward dominated by Cymbopogon nardus (65.4%), Themeda tremula (25.4%) andEulalia trispicata (10.1% of standing crop) and the lower site was a sparse sward dominated by C. nardus (68.6%) and Panicum maximum (13.9%) with somePennisetum polystachyon (7.7%). Total standing crop biomass was higher at the upper site than at the lower site and increased 4-fold at both sites over the years. Productivity estimates were 911.2 g/m² for the upper sites and 679.5 g for the lower site. There was no significant difference in the amount of C. nardus between sites, but the upper site supported a much denser sward of T. tremula accounting for the higher productivity of this site.