Glycolipid patterns

Labelled Neutral Glycolipids. Neutral glycolipids were labelled with -galactose. As was seen with the ganglioside, the butyrate affected the neutral glycolipid patterns but the most marked alterations appeared to be due to changes in the lipid moeities. 

When the individual proportions of lipids in membranes are examined more closely (right part of the illustration), typical patterns for particular cells and tissues are also found. The illustration shows the diversity of the membrane lipids and their approximate quantitative composition. Phospholipids are predominant in membrane lipids in comparison with glycolipids and cholesterol. Triacyl-glycerols (neutral fats) are not found in membranes. 

One of the most rapidly advancing areas in biochemistry is that concerned with the structure and metabolism of oligosaccharides that are covalently attached to proteins (in glycoproteins) and lipids (in glycolipids). The carbohydrates in these complexes vary in composition, in the way they are linked, their branching patterns and in the sugars that terminate each branch. 

Figure 10. Thin-layer pattern with deduced chemical formulas of non-acid glycolipids of epihtelial cells of the two rat strains (cf. Figure 2)...

Woodrosin I (65) is an ether-insoluble glycolipid isolated from the stems of Ipomoea tuberosa L. (Merremia tuberosa (L.) Rendle) commonly called woodrose after the shape of its dried calyx (28). Its lactone moiety spans four glucose units to form a 27-membered macrocycle. Further challenges arise from the additional acylation pattern at the periphery of the branched and hence highly hindered pentasaccharide perimeter of this glycoconjugate. 

Metallosphaera sedula [79h], which represents a new genus of aerobic metal-mobilizing thermophilic archaea in the order Sulfolobales, was found to contain a similar pattern of caldarchaeol and nonitolcaldarchaeol-derived glycolipids and the corresponding P-inositol phosphoglycolipids to those of Sulfolobus solfataricus (e.g., see structures 38, 38A, 44 and 44B, Fig. 8 [75,79]). However, the relative proportions of the major glycolipids (38 and 44) and the minor complex lipids of M. sedula differ somewhat from those of S. solfataricus. 

Despite the limited number of extreme thermophile species that have been examined for lipids, it appears that a few genera. Thermoplasma, Sulfolobus, Thermoproteus, Desulfurococcus, Thermococcus and Pyrococcus may be distinguished by their glycolipid and phosphoglycolipid compositions. However, it should be noted that genera in the Order Sulfolobales examined so far, such as Sulfolobus, Desulfurolobus and Metallosphaera have very similar lipid patterns, and it would be difficult to differentiate between them on the basis only of their lipids. 

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