Two neutral glycosphingolipids having large straight oligosaecharide chains with eight and nine sugars, provisionally named COS and CNS, were isolated and purified from larvae of the green-bottle fly, Lucilia caesar, as the only two remaining unidentified significant neutral glycolipids in this organism. From the results of sugar analysis, permethylation, negative-ion fast atom bombardment mass spectroscopy (FAB-MS), and 1H-NMR studies, the structures of the two glycolipids are proposed to be: COS, GalNAcβl-3GlcNAc/91-3Gal βl-3GalNAcal-4GalNAcβl-4GlcNAc;91-3Manβl-4Glcβl-Cer; and CNS, Galβl-3GalNAcβ l-3GlcNAc β l-3Gal §l-3GalNAc α l-4GalNAc β l-4GlcNAc β l-3Man β l-4Glc β1-Cer. The fatty acid and long-chain base compositions of the above glycolipids were very similar, and were dominated by arachidic acid, and tetradeca- and hexadeca-4-sphingenines. The great similarity between the compositions of their ceramide moieties suggests that COS may be a precursor in the glycosylation reaction yielding. © 1990 COPYRIGHT, 1990 BY THE JOURNAL OF BIOCHEMISTRY.
