Gangliosides of dogfish (Squalus acanthias) brain

Eighteen gangliosides were isolated from dogfish (Squalus acanthias) brain, and their structures and compositions were determined by methylation analysis, enzymatic hydrolysis and partial hydrolysis with mild acid. Tetra- and pentasialogangliosides were also analysed by liquid secondary ion mass spectrometry. The dogfish brain gangliosides were characterized by a variety of molecular species. The most abundant ganglioside was GM2 (22.8% of the total sialic acid content), followed by GQ1c (16.0%), GP1c (13.4%), and GD2 (12.5%). The abundance of gangliosides containing a gangliotriaose core (GM2 and GD2), and c-series polysialogangliosides (GQ1c and GP1c) was a prominent feature of dogfish brain, differing from the brain gangliosides of teleosts and other vertebrates. A battery of trisialogangliosides was also found. A ganglioside which had an a- and alpha-series hybrid-structure (IV3NeuAc,III6NeuAc,II3NeuAc-Gg4Cer) comprised 1.4% of the total. The major fatty acids comprised 16:0, 18:0, 18:1, 22:1 and 24:1. The gangliosides with a gangliotriaose core predominantly contained 22:1. Sphinganine and 4-sphingenine comprised the long-chain bases.