GLYCOSPHINGOLIPIDS IN INSECTS - THE AMPHOTERIC MOIETY, N-ACETYLGLUCOSAMINE-LINKED PHOSPHOETHANOLAMINE, DISTINGUISHES A GROUP OF CERAMIDE OLIGOSACCHARIDES FROM THE PUPAE OF CALLIPHORA-VICINA (INSECTA, DIPTERA)

A group of Calliphora vicina pupal glycolipids could be segregated from the neutral glycosphingolipids, according to their two-dimensional TLC migration properties and positive reactions toward ninhydrin and fluorescamine spray reagents. These classified zwitterionic glycolipids were isolated by silica-gel column chromatography and characterized by the presence of a N-acetyl-glucosamine-bound phosphoethanolamine residue. The structural elucidation of the oligosaccharide moieties was performed by the determination of constituent carbohydrates as alditol acetates, linkage analysis by permethylation, exoglycosidase cleavage, fast-atom-bombardment mass spectrometry and NMR spectroscopy. The dominant fatty acid and sphingoid base species of the ceramide moieties were C20:0 (arachidic acid) and C14.1 (tetradecasphing-4-enine), respectively. The chemical structures of the zwitterionic, biogenetic glycosphingolipid series were determined as: (PEtn-6')GlcNAc(beta-1 - 3)Man(beta-1 - 4)Glc-beta-Cer; GalNAc(beta-1 - 4) (PEtn-6')GlcNAc(beta-1 - 3)Man(beta-1 - 4) Glc-beta Cer; GalNAc(alpha-1 - 4)GalNAc(beta-1 - 4) (PEtn-6')GlcNAc (beta-1 - 3)Man(beta-1 - 4)Glc-beta-Cer; Gal(beta-1 - 3)GalNAc(beta-1 - 4) (PEtn-6')GlcNAc(beta-1 - 3)Man(beta-1 - 4)Glc-beta Cer; Gal(beta-1 - 3)GalNAc(alpha-1 - 4)GalNAc(beta-1 - 4) (PEtn-6')GlcNAc(beta-1 - 3)Man(beta-1 - 4)Glc-beta Cer; GlcNAc(beta-1 - 3)Gal(beta-1 - 3)GalNAc(alpha-1 - 4)GalNac (beta-1 - 4) (PEtn-6')GlcNAc(beta-1 - 3)Man(beta-1 - 4)Glc-beta Cer.