Intra- and extracellular lipids in cultures of the toxic dinoflagellate, Gyrodinium aureolum

Abstract

Gyrodinium aureolum is a North Atlantic red tide species of dinoflagellate which has frequently caused mortality of marine organisms in coastal waters and is a serious problem for the European fish farming industry. We describe here, for the first time, the lipid composition of extracts of cultures of an isolate of G. aureolum which is known to be toxic. Large volume samples were taken in the stationary phase of cultures grown at 13° and 18°. The lipids in extracts of G. aureolum cells and their exudates were analysed using TLC-FID, GC-FID and MS-MS. Polar lipids, including glycolipids and phospholipids, were the major type of lipids within the cells and in the exudates. Triacylglycerols were also prominent within the cells, while free fatty acids were prominent in the exudates. All- cis-3,6,9,12,1 5-octadecapentaenoic acid (18: 5n3) comprised 12–18% of the fatty acids in cell extracts and was the major unsaturated fatty acid present in cells from the warmer culture. The extracellular lipids contained considerably more monoeneoic, dieneoic and triencoic fatty acids than did the intracellular lipids, but had lower amounts of other unsaturated fatty acids.