Identification of 3, 6, 9, 12, 15‐octadecapentaenoic acid in laboratory‐cultured photosynthetic dinoflagellates

Abstract

Polar and nonpolar chromatograms of fatty acid methyl esters derived from 11 species of photosynthetic, marine dinoflagellates cultured in modified Erd-Schrieber medium contained a component (4-23%) not identifiable by conventional graphic or arithmetic methods. Hydrogenation followed by gas liquid chromatography of the product showed the unknown component to be a straight chained 18 carbon fatty acid methyl ester. Chemical (ch4) ionization mass spectrometry of the isolated ester gave a spectrum characteristic of methyl esters and a mol wt of 288, indicating an 18 carbon molecule with 5 double bonds, or equivalent unsaturation. The IR spectrum showed that the double bonds are nonconjugated, and all are cis in geometry. Electron impact mass spectrometry of the pyrorolidide derivative provided evidence that double bonds are located in the 3, 9, 15 positions and probably also in the 6 and 12 positions of the molecule. these double bond positions were confirmed by NMR spectrometry. Data obtained by quantitation of the algal methyl esters suggest the possibility that these dinoflagellates synthesize 18:5omega3 (shorthand notation for chain length: number of double bond counted from the terminal methyl group) by a 2 carbon chain shortening of 20:5omega3, rather than by the insertion of a delta3 bond into 18:4omega3.

Seasonal variations in the lipid and fatty acid composition of the euphausiid Meganyctiphanes norvegica from the Ligurian Sea

“…Dinophyceae (dinoflagellates), Haptophyceae (coccolithophorids), Prymnosiophyceae (Phaeocystis spp. ), Chlorophyceae and Prasinophyceae (green microalgae) are rich in C18 polyunsaturated acid (Joseph 1975, Volkman et al 1981, Claustre et al 1989, Dunstan et al 1992. Myristic acid (14:O) is a prominent fatty acid in diatoms and coccolithophorids (Ackman et al 1964, 1968, Volkman et al 1981 and is usually absent from the polar lipids of pelagic consumers (Sargent & Whittle 1981).…”

Lipid composition of stomach oil in a procellariiform seabird Puffinus tenuirostris: implications for food web studies

“…For instance, 16:4n-1, 18:5n-3 or 20:1n-9 and 22:1n-13+11 fatty acids are characteristics of plankton assemblages dominated by diatoms, dinoflagellates (some Haptophycae) and Calanus spp. type copepods, respectively (Ackman et al 1964, Joseph 1975, Mayzaud et al 1976, Pascal & Ackman 1976. Ratios among fatty acids have also been used to clarify the dominant trophic interactions between zooplankton and phytoplankton or zooplankton and higher trophic levels.…”

Sources of C20-polyunsaturated fatty acids for biotechnological use

“…Euglena gracilis is the typical phytoflagellate in which relatively high concentrations of arachidonic and docosapentaenoic acids have been found, including in dark-grown cells (Nichols and Appleby 1969;Fouche and Coniglio 1977). The occurrence of octadecapentaeonic acid (18:5 oJ3) appears be a useful taxonomic criterion for classifying marine plankton as dinoflagellates (Joseph 1975;Mayzand et al 1976;Jones et al 1983). Joseph (1975) demonstrated that 11 species of laboratory-cultured, photosynthetic dinoflagellates contained 4-23% of this fatty acid, which, however, was produced by 2-carbon-chain shortening of eicosapentaenoic acid (20:5 o~3).…”

“…The occurrence of octadecapentaeonic acid (18:5 oJ3) appears be a useful taxonomic criterion for classifying marine plankton as dinoflagellates (Joseph 1975;Mayzand et al 1976;Jones et al 1983). Joseph (1975) demonstrated that 11 species of laboratory-cultured, photosynthetic dinoflagellates contained 4-23% of this fatty acid, which, however, was produced by 2-carbon-chain shortening of eicosapentaenoic acid (20:5 o~3). Other polyunsaturated fatty acids have been detected in dinoflagellates (Harvey et al 1988).…”