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 Cage culture of the snakehead Ophicephalus striatus in a peaty swamp in Sri Lanka In. Zhou, et al. (eds).(Asian Fisheries Society, Manila, Philippines, 1997) Wijeyaratne, M.J.S.Item Laboratory and field studies with biopesticides and a chemical insecticide against live-wood termite, Postelectrotermes militaris (Desneux)(Proceedings of the 15th Annual Sessions of the Institute of Biology of Sri Lanka, September, 1995) Amarasinghe, L.D.; Abeysinghe, L.S.Item Clonal susceptibility and population dynamics of Tea red spider mite, Oligonychus coffeae Nietner, (Acarina:Tetranichidae)(Proceedings of the 45th Annual sessions of the Sri Lanka Association for the Advancement of Science, 1989) Thirugnanasuntharan, K.; Amarasinghe, L.D.Item The response of the up-country live wood termite (Postelectrotermes militaris, Desneux, (Isoptera:Kalotermitidae) to termite extracts and roots of plants(Proceedings of the 44th Annual sessions of the Sri Lanka Association for the Advancement of Science, 1988) Thirugnanasuntharan, K.; Amarasinghe, L.D.Item Prevelance and distribution of entomopathogenic nematodes in dondra coastal belt in Sri Lanka(Proceedings of the 53rd Annual sessions of the Sri Lanka Association for the Advancement of Science, 1997) Premachandra, W.T.S.D.; Amarasinghe, L.D.; Wickremasinghe, M.G.V.Item Occurrence of entomopathogenic nematodes in six sites along the southern coastal belt of Sri Lanka(Proceedings of the 18th Annual sessions of the Institute of Biology of Sri Lanka, September, 1998) Premachandra, W.T.S.D.; Amarasinghe, L.D.; Wegiriya, H.C.E.Item A comparative assessment of the fisheries in lacustrine inland waters in three Asian countries based on catch and effort data(Fisheries Research, 1991) de Silva, S.S.; Moreau, J.; Amarasinghe, U.S.; Chookajorn, T.; Guerrero, R.D.The catch and effort data of the artisanal fisheries of the natural lakes and reservoirs in the Philippines, and reservoirs in Sri Lanka and Thailand are evaluated. The yield (kg ha?1 year?1) to effort relationship of the Philippines lakes and Thai reservoirs conformed to a second-order curve, and that of Sri Lankan reservoirs was linear. Similarly, the catch per unit effort (CPUE) to effort per unit area relationships for the Philippines and Thai fisheries were similar and conformed to the Fox model. The relationship of the mean annual yield (kg ha?1) to mean effort in the Sri Lankan reservoirs when considered as a whole, on a yearly basis, conformed to the Schaefer model. On the basis of these relationships the effort which gave the maximum yield per annum was computed for each fishery. The yields were 515, 256 and 93 kg ha?1 for efforts of 20, 6.4 and 10 fishermen for the fisheries of the Philippines, Sri Lanka and Thailand, respectively. An attempt is made to explain the reasons for the apparent differences in these three artisanal fisheries, and the importance of the models in the management of the respective fisheries are discussed. 1 Present address: Deakin University, Warrnambool Faculty of Applied Science and Environmental Technology, P.O. Box 423, Warrnambool 3280, Australia.