Systematic position of fish species and ganglioside composition and content

The ganglioside content in brain of cartilaginous and bony fishes studied varies from 110 to 581 and from 104 to 595 micrograms sialic acid per g of wet weight respectively. A high degree of alkali lability and the predominance of C18-sphingosine and N-acetylneuraminic acid are typical of fish brain gangliosides. A high content of oligosialogangliosides with four and more residues of sialic acid and the predominance of gangliosides with gangliotetraosyl carbohydrate chain are characteristic for teleost brain. No pronounced difference was revealed in ganglioside composition and content of clupeomorphs and percomorphs. Gangliosides with short (lactosyl and gangliotriaosyl) carbohydrate chain predominate in brain of all cartilaginous fishes studied. A statistically significant difference was found in ganglioside content, relative oligosialoganglioside content and ganglioside fatty acid composition of squalomorphs and rajiformes, on one hand, and dasyatiformes and galeomorphs, on the other hand.