| Abstract
| - Total neutral and acidic glycosphingolipids were prepared from whole tissues of the sea-water bivalve, Meretrix lusoria, and the former preparation was further fractionated into subgroups by silicic acid column chromatography. The fractions obtained as mono-(ceramide monosaccharide, CMS), di-(CDS) and triglycosylcer amides (CTS) were characterized by thin-layer chromatography, partial hydrolysis with exoglycosidases, methylation studies, CrO3, oxidation, and GLC analysis of the component sugars, fatty acids and long-chain bases. The following structures are proposed: Gal-Cer and Glc-Cer for CMS, Gal(β1→4) and Man(β1→4)Glc-Cer (MlOse2Cer) for CDS, Man(α1→3) Man (α1→3) Man (β1→4)Glc-Cer and (β1→4)-Gal (α1→3) Man (β1→4) Man (β1→4)Glc-Cer (II3MlOse2Cer) for CTS. To our knowledge II3αGal-MlOse2Cer) has not previously been reported. The fatty acid composition of CMS, CDS, and CTS consisted almost entirely of saturated C16-C24 acids with large amounts of 2-hydroxypalmitic acid and 2-hydroxystearic acid. The long-chain bases consisted of 4-sphingenine and 4,8-sphingadienine. More complex neutral glycolipids than CTS, as well as an acidic glycolipid, were examined by TLC and GLC of the constituent sugars, and an immunochemical technique. They contained tetra- to nonasaccharides as sugar moieties arid the structures are suggested to be as follows: GlcNAc(β1→2) Man(α→3) Manα→4) Glc-Cer (Lipid I, MlOse4Cer) GlcNAc(β1→2)Man(α1→3)[Xyl(β1→2)Man(β4)Glc-Cer (Lipid II, MlXOse4Cer); Fuc3Me(α1→2)Xyl3Me(β→4)[GalNAc3Me-(α→3)]Fuc(α→4)GlcNAc(β1→2)Man(α→3)[Xyl(β1→2)Man(β1→4)Glc-Cer
|
