Glycolipids neutral glycosphingolipids

An HPLC method for neutral glycosphingolipids was first designed for the analysis of human plasma glycolipids (3), which consist primarily of glucosylceramide, lactosylceramide, globo-triaosylceramide and globotetraosylceramide (globoside). 

Figure 1. Schematic of the effects of brief treatment with mild alkali on the thin-layer chromatographic migrations of three types of glycolipids. 1, 2 control and alkali-treated neutral glycosphingolipid 3, 4 control and alkali-treated galactosyl-alkylacylglycerol 5, 6 control and alkali-treated galactosyldiacylglycerol. OR origin FR solvent front.

Neutral glycosphingolipids have also been studied in human skeletal (8) and cardiac (9) muscle. In skeletal muscle, lacto-sylceramide is the predominant glycolipid (38.4%) followed by globotriaosylceramide (26.3%) and globoside (12.4%) while in heart, globoside predominates (43.0%) followed by globotriaosylceramide (32.0%). 

The neutral lipid fraction from the DEAE-Sephadex A-50 column was combined with the lower phase obtained after Folch partition of the total lipid extract and the combined lipids dried. To the same flask, 10Q ml of 0.6 M NaOH in methanol was added. The mixture was incubated at 37°C for 5 hours. Five volumes of acetone were then added and stored overnight at 4°C. The precipitate was collected by centrifugation at 4°C and dissolved in C M (4 1, v/v). After application to the column (2.0 x 25 cm), the column was washed with chloroform. Neutral glycolipids were then eluted with tetrahydrofuran H2O (10 1). Fractions containing neutral glycosphingolipids were pooled and their glycolipid content examined by thin-layer chromatography. 

Glycosphingolipids with similar structures are found in Crithidia spp, which are considered to be lower trypanosomatids as their habitat is in invertebrate and since they do not have a cycle involving vertebrates (39). Neutral glycosphingolipids were isolated and characterized in Crithidia luciliae, C.oncopelti and C.guilhermei (40). The major glycolipids of the three species of Crithidia detected by HPTLC chromatography contain... 

The five major neutral glycosphingolipids of human plasma have been characterized and each has a structure which has been identified previously. One of these glycolipids, D-glucosylceramide, and possibly a second, lactosyl ceramide, exchange between plasma and erythrocyte pools. The conclusion is drawn in terms of the relative roles of carbohydrate and lipid moieties of the glycosphingolipids in maintaining that association with erythrocyte membranes. 

Neutral glycosphingolipids containing D-mannose have been extracted from whole tissues of the fresh-water bivalve Corbicula sandai. Chemical, enzymic, and physical methods were used to characterize two novel glycolipids, viz. jS-D-mannopyranosyl-(l -s- 4)-D-glucopyranosylceramide and a-D-mannopyranosyl-(1 -> 4)-j8-D-mannopyranosyl-(l 4)-D-glucopyranosylceramide, The compositions of the sialosphingolipids of sea-urchin eggs and spermatozoa have been... 

Examination of the neutral glycolipids in the aqueous fraction of a buffered tetrahydrofuran extract of dog gastric mucosa indicated presence of glycosphingolipids containing significant amounts of N-acetylgalactosamine, but only traces of fucose (26). 

Extensive purification of the glycosphingolipids present in the neutral fraction resulted in the isolation of three distinct glycolipids exhibiting Forssman antigenic activity (Table I, compounds 9,10,11). Thin-layer chromatographs of these glycolipids is illustrated in Fig. 1. Chemical analyses of the purified... 

The fact that only one type of complex glycosphingolipid (enriched in galactose) was obtained may have reflected the procedure of purification, especially the choice of a Florisil column and the solvents used for elution of acetylated compounds. This possibility became obvious when the neutral glycolipid fraction of the... 

Neutral glycolipids from animal tissue (without sialic acid) are nearly exclusively glycosphingolipids. Families are classified according to the sequence of mono-... 

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