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  • 1
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Synaptic plasma membranes (SPM) and synaptic junctions (SJ) were isolated from the cortices of rats varying in age between 5 and 28 days. Gel electrophoresis of SPM and SJ indicated a marked increase in the concentration of the “PSD protein” (M. W. 52,000) with development. The biosynthesis of glycoproteins was measured following the intracranial injection of [3H]fucose or [3H]N′-acetylmannosamine. The incorporation of [3H]fucose into synaptic fractions decreased two- to threefold between 10 and 28 days whereas little change in the incorporation of [3H]N′-acetylmannosamine occurred over the same period. Gel electrophoretic analyses of labeled synaptic membranes indicated major increases in the relative incorporation of radiolabeled precursors into glycoproteins with apparent molecular weights of 74,000, 65,000, 50,000, and 40,000 with increasing age. Identification of fucosyl and sialyl glycoproteins following reaction with 125I-fucose-binding protein or labeling of sialic acid with NaIO4NaB[3H4] demonstrated similar increases in the concentrations of these glycoproteins. Synaptic junctions contained three major glycoproteins with apparent molecular weights of 180,000, 130,000 and 110,000. The reaction of these glycoproteins with 125I-fucose-binding protein increased one- to twofold between 10 and 28 days but little variation in their relative distribution or synthesis occurred over this period. The reaction of synaptic junctional glycoproteins GP 180 and GP 110 with 125I-wheat germ ag-glutinin increased between 10 and 28 days. The results indicate that the molecular composition of the synapse continues to evolve after the initial synaptic contact has been formed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 41 (1983), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Synaptic junctions (SJs) were isolated from the forebrains of rats ranging in postnatal age from 10 days to greater than 1 year. SJ glycoproteins that react with Concanavalin A (Con A) were isolated by chromatography on Con A-agarose and separated by gel electrophoresis. The concentrations of the major SJ Con A binding (Con A+) glycoproteins (apparent Mr 180,000, 130,000, and 110,000) increased between 10 and 28 days, with GP180 and GP110 showing greater relative increases than GP130. Con A binding oligosaccharides associated with 10-day SJs were sensitive to digestion with endoglycosidase C11 and α-mannosidase, indicating that they were of the high-mannose type, as previously shown for 28-day SJs. Con A+ oligosaccharides from rats of increasing postnatal age were analyzed by chromatography on Biogel P-4. Two major oligosaccharides, containing five and eight mannose residues, were present in SJs of all ages examined. During development the ratio of man5 to man8 oligosaccharides increased, so that man5 constituted the predominant species in 28-day and adult SJs. Peptide mapping experiments showed that GP180, GP130, and GP110 were each associated with a unique polypeptide composition. Little or no change in peptide composition of the major SJ glycoproteins occurred during development.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 39 (1982), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Glycoproteins were isolated from a rat brain synaptic junction fraction by affinity chromatography on Concanavalin A-agarose. The isolated glycoproteins were digested with pronase and radiolabeled with 125I-Bolton Hunter reagent, and 125I-Concanavalin A-binding glycopeptides were isolated by chromatography on Concanavalin A-agarose. Treatment of the 125I-Concanavalin A-binding glycopeptides with either α-mannosidase or endo-β-N-acetylglucosaminidase-C11 abolished their interaction with Concanavalin A. The pronase digest was reacted with endo-β-N-acetylglucosaminidase-C11 and released oligosaccharides were reduced with NaB3H4. Following affinity chromatography on Concanavalin A-agarose, Concanavalin A-binding [3H]oligosaccharides were chromatographed on Biogel P4. Two major oligosaccharides corresponding to standard carbohydrates containing eight and five mannose residues were identified. Treatment of these oligosaccharides with α-mannosidase converted them to smaller saccharides having a mobility on Biogel P4 columns equal to the standard disaccharide mannose-β-1-4-N′-acetylglucosamine. These results demonstrate that the Concanavalin A receptor activity associated with CNS synaptic junctions resides in asparaginelinked oligosaccharides of the high-mannose type.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0533
    Keywords: Canine distemper virus ; Demyelination ; Plasmalogenase ; Phospholipase ; Arachidonic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Three weeks after inoculation of 24-day-old gnotobiotic dogs with Snyder-Hill canine distemper virus, white matter samples were taken from the primary predilection sites for canine distemper virus-associated demyelination. The plasmalogenase activity in extracts was nearly 6-fold greater than control values for a dog with extensive demyelination and was not detectable in tissue from a dog with non-demyelinating lesions. Acid and neutral phospholipases A1 and A2 were assayed in homogenates and extracts with phosphatidyl ethanolamine substrates. Phospholipase A2 activities at both pH 4.3 and pH 6.8 were less in the dog with severe demyelinating lesions than in dogs with less severe lesions. Phospholipase A1 activities were generally similar for all four dogs. The marked elevation of plasmalogenase activity in demyelinating tissue may be associated with a release from the plasmalogens of arachidonic acid which is converted to oxygenated metabolites that may then be responsible for the inflammation. Phospholipases acting on phosphatidyl ethanolamine do not seem to be involved in the pathogenesis of demyelination associated with canine distemper virus.
    Type of Medium: Electronic Resource
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