STRUCTURAL ELUCIDATION OF 2 NOVEL AMPHOTERIC GLYCOSPHINGOLIPIDS FROM THE EARTHWORM, PHERETIMA-HILGENDORFI

The novel amphoteric glycosphingolipids containing a choline phosphate were purified from whole tissues of the earthworm, Pheretina hilgendo rfi. Their chemical structures were completely characterized as cholin ephosphoxyl --> 6(Man alpha 1-4)Gal beta 1-6Gal beta 1-1Cer (cholineph osphorylmannosylneogalabiaosylceraminde, named PGL3a) and cholinephosp horyl --> 6Gal beta 1-->6Gal beta 1-6Gal beta 1-1Cer (cholinephosphory lneogalatriaosylceramide, named PGL3 b) by compositional sugar, fatty acid and sphingoid analyses, hydrogen fluoride degradation, partial ac id hydrolysis, methylation analysis, exoglycosidase degradation, proto n magnetic resonance spectroscopy and fast atom bombardment mass spect rometry. The ceramide moieties of these lipids consisted of 22:0, 23:0 and 24:0 acids as major fatty acids, and branched octadeca- and nonad eca-4-sphingenines and octadeca-4-sphingenine as main sphingoids. Sinc e the oligosaccharides and the ceramide moieties of PGL3a and PGL3b we re identical with those of neutral glycosphingolipids found in this or ganism, the biosynthesis of the amphoteric glycolipids may occur by th e addition of a choline phosphate residue to the corresponding neutral glycolipids, Man alpha 1-4Gal beta 1-6Gal beta 1-1Cer or Gal beta 1-6 Gal beta 1-6Gal beta 1-1Cer.