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Biomedical subjects

Y L Fong

Publications and source records attributed to Y L Fong.

29 records · Page 2Linked to original sources
PubMed1986

Purification and characterization of two inactive/latent protein phosphatases from pig brain.

Two inactive/latent protein phosphatases termed LP-1 (Mr 260,000) and LP-2 (Mr 350,000) were identified and purified from pig brain. Examination of molecular structures indicated that LP-1 has three subunits with molecular weights of 69,000, 55,000, and 34,000, respectively, whereas LP-2 contains only one subunit, with molecular weight of 49,000. When using phosphorylase a as a substrate, LP-1 was completely inactive and could be dramatically activated by freezing and thawing in 0.2 M 2-mercaptoethanol, whereas LP-2 contained some basal activity but could also be stimulated 40-fold by the same treatment. Kinetic analysis further indicated that both LP-1 and LP-2 enzymes dephosphorylate histone 2A, myelin basic protein, and phosphorylase a at a rather comparable rate, but the dephosphorylation of histone 2A and myelin basic protein seems to be spontaneously active. This, together with the results that trypsinolysis could specifically knock off phosphorylase phosphatase activity but caused no effect on the associated myelin basic protein/histone phosphatase activities, supports the notion that a two-site mechanism may possibly be involved in the regulation of substrate specificity of LP-1 and LP-2 enzymes in the central nervous system.

Animals↗
PubMed1985

Identification and characterization of an ATP.Mg-dependent protein phosphatase from pig brain.

Substantial amounts of ATP.Mg-dependent phosphorylase phosphatase (Fc. M) and its activator (kinase FA) were identified and extensively purified from pig brain, in spite of the fact that glycogen metabolism in the brain is of little importance. The brain Fc.M was completely inactive and could only be activated by ATP.Mg and FA, isolated either from rabbit muscle or pig brain. Kinetical analysis of the dephosphorylation of endogenous brain protein indicates that Fc.M could dephosphorylate 32P-labeled myelin basic protein (MBP) and [32P]phosphorylase alpha at a comparable rate and moreover, this associated MBP phosphatase activity was also strictly kinase FA/ATP.Mg-dependent, demonstrating that MBP is a potential substrate for Fc.M in the brain. By manipulating MBP and inhibitor-2 as specific potent phosphorylase phosphatase inhibitors, we further demonstrate that 1) Fc.M contains two distinct catalytic sites to dephosphorylate different substrates, and 2) brain MBP may be a physiological trigger involved in the regulation of protein phosphatase substrate specificity in mammalian nervous tissues.

Adenosine Triphosphate↗
PubMed1978

Freshwater snail consumption and angiostrongyliasis in Malaya.

A survey of the freshwater snails, Pila scutata and Bellamyia ingallsiana, as food consumed by the local population was carried out in Peninsular Malaysia. Of these two species the first is preferred; the sizes favoured are between 25--40 mm. Pila snails were found to be consumed by the three communities, viz. Malay, Chinese and Indian, in different ways. The various methods of preparing the snails for consumption are described. P. scutata is an intermediate host of the rat-lung worm, Angiostrongylus malaysiensis. As this worm presumably is the causative agent of human eosinophilic meningoencephalitis, the eating habits of the three races in consuming the snail in relation to the epidemiology of the disease was also discussed.

Animals↗
PubMed1977

Capillaria hepatica infection of wild rodents in Peninsular Malaysia.

Capillaria hepatica infection in wild rodents collected from the States of Kelantan, Selangor and Johore in Peninsular Malaysia since 1973 is reported. A total of 1,258 rodents consisting of 20 species of house, field and forest rats, and 7 species of squirrels were examined for the parasite and 17 species consisting of 111 murids and 1 flying squirrel were found infected. The house rat, Rattus norvegicus had the highest prevalence rate, followed by 3 species of field rats, R. tiomanicus, R. argentiventer and Bandicota indica. The prevalence of infection was low among forest rats with the exception of Lenothrix canus. Only 1 flying squirrel, Hylopetes spadiceus was found with the parasite. The prevalence of infection in relation to the host behaviour and habitats was discussed. C. hepatica appears to be widespread throughout Malaysia with a wide range of hosts among rodent species. Some new host records are presented herein.

Animals↗
PubMed1976

Angiostrongylus malaysiensis from Tuaran, Sabah, with reference to the distribution of the parasite in Malaysia.

A survey of Angiostrongylus malaysiensis among wild rodent and molluscan hosts was made in the Tuaran Central Agricultural Research Station and within the vicinity of Tuaran, Sabah. Three of 19 Rattus rattus diardii, one of 2 R. exulans and one R. argentiventer were found naturally infected with the parasite. In this survey 56 of 382 molluscs comprising of Pila scutata, Achatina fulica and two species of land slugs, Laevicaulis alte and Microparmarion malayanus, were found naturally infected with the parasite. Samples of larvae from each of these molluscs were experimentally transferred to laboratory albino rats and adult worms consistent with A. malaysiensis were recovered. Comparison of the rat hosts and the molluscan intermediate hosts of the parasite in Peninsular Malaysia, Sarawak and Sabah was made, and the finding of A. malaysiensis in Tuaran is the first report of the parasite from Sabah. The distribution of the parasite throughout Malaysia is discussed. Observation on the human consumption of the freshwater snail, P. scutata, was made. Although the infection rate of this snail is low compared with other molluscan hosts examined. The importance of this mollusc as a potential source of human infection should not be overlooked. Hospital records for 1974 and 1975 were examined and clinical human angiostrongyliasis was rarely recorded in Sabah.

Animals↗