Glycolipids animal, occurrence

Echinoderms constitute a peculiar phylum of invertebrates belonging to the most highly organized animals, the Deuterostomia, including, also, all the phyla of chordates. Among the invertebrates, echinoderms are the richest in glycolipids, and differ from all of the other marine invertebrate phyla in that they contain sialoglycolipids.79 This conforms to the data of Warren, who studied the occurrence of sialic acids in Nature, and found that all of the vertebrates have them, but, of the invertebrates, only the echinoderms practically all of the Protostomia contain no sialic acids.274... 

Both forms of sialic acid, N-acetyl- and N-glycolylneuraminic acid (cf. Chapter 1), may coexist at the surface of the same cell, as shown in the murine TA3-Ha cancer cell by Codington et aL (1970). In the erythrocyte, the proportion ofN-acetyl- and N-glycolylneuraminic acid is similar to that of these compounds in other tissues, and varies with the animal species (Klenk, 1958a). No information is available at the present time on the occurrence and relative proportions of the O-acetyl derivatives of sialic acid at the surface of the mammalian cell. The absolute and relative amounts of sialic acid residues linked either to glycoproteins or to glycolipids vary widely and have been determined only on the erythrocytes of a few animal species (Uhlenbruck and Wintzer, 1970). 

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