Studies on glycosphingolipids of larvae of the green-bottle fly, Lucilia caesar. II. Isolation and structural studies of three glycosphingolipids with novel sugar sequences.

Three novel glycosphingolipids containing five to seven sugars in their saccharide chains have been isolated from larvae of the green-bottle fly, Lucilia caesar. The structures of these glycolipids were identified by sequential enzymatic degradation with exoglycosidases, methylation analysis, and partial acid hydrolysis to be: Gal-NAc alpha (1-4)GalNAc beta (1-4)GlcNAc beta (1-3)Man beta (1-4)Glc-Cer, Gal alpha (1-4)GalNAc alpha (1-4)GalNAc beta (1-4)GlcNAc beta (1-3)Man beta (1-4)Glc-Cer, and GlcNAc beta (1-4)Gal alpha (1-4)Gal-NAc alpha (1-4)GalNAc beta (1-4)GlcNAc beta (1-3)Man beta (1-4)Glc-Cer. It should be noted that one N-acetylgalactosamine in their saccharide chains is alpha-glycosidically linked to another N-acetylgalactosamine by a 1-4 bond and that this is the first example of the presence of an alpha (1-4) linked galactosamine unit in nature. The major fatty acids were normal saturated fatty acids with carbon numbers of 16 to 22. The long-chain bases were dominated by C14 and C16-4-sphingenine homologues.