Distribution of Fatty Acids in Lipids of the Common Atlantic Sea Urchin Strongylocentrotus droebachiensis

Abstract

Lipid classes and fatty acid details of sea urchins Strongylocentrotus droebachiensis harvested in subtidal water near Halifax, and in deep water in St. Margaret's Bay, were compared. All samples contained an eicosenoic acid with 5,6-ethylenic unsaturation and two non-methylene-interrupted eicosadienoic acids (NMID) with the one 5,6 bond and a second in either the 11,12 or 13,14 positions. Structures were identified by combinations of ozonolysis, partial hydrazine reduction and argentation-TLC and by mass spectra of pyrrolidine derivatives. No 3,11-eicosadienoic acid was observed and elongation of C₂₀ materials with few ethylenic bonds to C₂₂ homologues was confined to 11–20:1 and to the minor 5,13–20:2 NMID and did not include either the relatively important 5–20:1. monoene or the 5,11–20:2 NMID. Individual animals showed considerable variation in total lipid and lipid classes, but the consistent distribution of the fatty acids with 5,6 unsaturation, irrespective of the nutritional status of the animal, suggests a basic role in membrane function.Key words: Strongylocentrotus droebachiensis, sea urchin lipids, sea urchin fatty acids, non-methylene-interrupted fatty acids, eicosadienoic fatty acids