Characterization of two molecular species GD3 ganglioside from bovine buttermilk

Two gangliosides, representing 85% of total lipid-bound sialic acid, have been isolated from bovine buttermilk and characterized. Both contained long-chain base, glucose, galactose and sialic acid in the molar ratio 1:1:1:2, and gave, upon sialidase treatment, a neutral glycolipid, characterized as lactosylceramide. Partial acid hydrolysis, permethylation analysis and chromium trioxide oxidation indicated their basic oligosaccharide portion to be NeuAc\u3b12 \u2192 8NeuAc\u3b12 \u2192 3Gal\u3b21 \u2192 4Glc. The difference bteween the two forms was exclusively in the ceramide moiety of the molecule, one containing mainly long-chain (C22-C25) fatty acids and an equimolar proportion of C16 and C18 long-chain bases, and the other mainly palmitic acid and C18 long-chain base

Characterization of membrane components of the erythrocyte involved in Vesicular Stomatitis Virus attachment and fusion at acidic pH

Goose erythrocyte membranes were isolated and tested for their ability to compete with red cell receptors for vesicular stomatitis virus (VSV) attachment and fusion at acidic pH. Crude membranes, solubilized with Triton X-100, Tween 80 and octyl-beta-D-glucopyranoside, showed a dose-dependent inhibitory effect on virus binding and haemolysis. The chemical nature of the active molecules was investigated by enzyme digestion and by separation of purified components. Only the lipid moiety, specifically phospholipid and glycolipid, was found to inhibit VSV attachment; a more detailed analysis of these molecules showed that phosphatidylinositol, phosphatidylserine and GM3 ganglioside were responsible for the inhibitory activity and could therefore represent VSV binding sites on goose erythrocyte membranes. Removal of negatively charged groups from these molecules by enzymic treatment significantly reduced their activity, suggesting that electrostatic interactions play an important role in the binding of VSV to the cell surface. Enzymic digestion of whole erythrocytes confirmed the involvement of membrane lipid molecules in the cell surface receptor for VSV

inhibition of rabies virus infection by a soluble membrane fraction from the rat cemtral nervous system

This paper describes the inhibitory effect of a normal rat brain solubilized membrane preparation (RBSM-liposomes) on rabies virus infection. Rabies virus was incubated with RBSM-liposomes or their separated components (proteins, phospholipids, gangliosides) before infection of CER or neuroblastoma cells. In addition, both RBSM-liposomes and target cells were treated with enzymes prior to the infection step. All these experimental procedures showed that the active components were mainly lipids