Myelin gangliosides in vertebrates.

A phylogenetic survey of brain myelin ganglioside patterns and concentrations has been carried out on 16 vertebrate species. Gangliosides were isolated from purified myelin and found to vary in concentration from 25 micrograms of sialic acid per 100 mg of myelin for goldfish to a value of 395 for turkey. The latter species had approximately equivalent amounts of GM1 and GM4 as the two major gangliosides. The 11 mammals studied all had GM1 as the major ganglioside, with variable amounts of GM4; rhesus monkey and human had 20-25% GM4, whereas the others had less than 10%. Amphibia and fish myelin contained the least total ganglioside, with patterns that showed relatively little GM1 and no detectable GM4. Alligator myelin was unique in having a total concentration as high as the avian species, but a pattern with predominantly di- and trisialo gangliosides.