SUCCESSIVE ISOLATION AND SEPARATION OF THE MAJOR LIPID FRACTIONS INCLUDING GANGLIOSIDES FROM SINGLE BIOLOGICAL SAMPLES

Currently available techniques concerning extraction and characterizat ion of the different lipids from biological specimens are designed for particular families and do not address consecutive isolation of lipid constituents in their globality, We describe here a sim ple, nondestr uctive chromatographic procedure that allows efficient elution and fur ther analysis of the major lipid classes (neutral lipids, phospholipid s, nonsialylated sphingolipids, and gangliosides) in their natural sta tes from the same starting material, The procedure describes the use o f solvent mixtures adapted to silicic acid column chromatography and p ermits 90-97% recovery of each of the above lipid groups, We have part icularly concentrated on optimizing the efficient recovery of the dive rse minor forms of gangliosides, free of other contaminants, from rela tively small amounts of neural tissue, As model systems we have used i n vivo and in vitro preparations of mammalian retina for which only fr agmentary data are available on lipid composition, We show that relati ve to brain, retina contains, for example, twofold more sphingomyelin and sixfold more GD3 ganglioside, In turn, cultured retinal glial cell s contain twofold higher levels of globoside and eightfold higher amou nts of GM3 ganglioside with respect to intact retina, Compared to prev iously published techniques, we obtain improved total ganglioside reco very, with enrichment of poly-sialogangliosides. The technique present ed here should be widely applicable to analyze global lipid compositio n of diverse biological samples. (C) 1997 Academic Press.