Science
Permanent URI for this communityhttp://repository.kln.ac.lk/handle/123456789/1
Browse
302 results
Search Results
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 Effects of Fusarium moniliforme culture extracts and fumonisin B1 on DNA, RNA and protein synthesis by baby hamster kidney cells(Springer Netherlands., 1998) Abeywickrama, K.; Bean, G.A.; Kennedy, K..A.Baby hamster kidney cells (BHK-21) were exposed to culture filtrates of 4 Fusarium moniliforme isolates containing varying levels of fumonisin B1 (FMB1) and the effects upon RNA, DNA and protein synthesis were monitored. Cells were also grown on medium amended with FMB1 only for comparison. After 24 h incubation FMB1 (100 μg/100 ml medium) reduced protein synthesis by 4% and by 18% after 48 h. Culture filtrates containing the highest levels of FMB1 also caused the greatest inhibition in protein synthesis after 24 h but after 48 h protein synthesis levels were the same as controls even though the FMB1 level was 360 μg/100 ml. Only FMB1 reduced DNA synthesis, by 8% after 24 h but after 48 h DNA levels had increased by 40 % over controls. The culture filtrates containing the highest levels of FMB1 (360 μg/100 ml) reduced DNA synthesis more than 50% after 24 h and 48 h. Culture filtrates containing lesser amounts of FMB1 in some instances stimulated DNA synthesis and inhibited it in others. There was also no correlation in the level of FMB1 with the inhibition of RNA synthesis by BHK cells. It appears that metabolites other than fumonisin produced by F. moniliforme in culture can affect and both stimulate and inhibit RNA, DNA and protein synthesis by BHK cells.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 Isolation and identification of fungi from mushroom composts and evaluation their biological activity(1999) Wickremasinghe, R.; Abeywickrama, K.P.; Abeythunga, D.T.U.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.