Positional Distribution of Fatty Acids in Glycerolipids of the Marine Red Alga, Porphyra yezoensis

The positional distribution of fatty acids in glycerolipidsfrom thalli of Porphyra yezoensis was studied by enzymatic hydrolysis.In monogalactosyl diacylglycerol, icosapentaenoic acid was amajor fatty acid at both the sn-1 and sn-2 positions of theglycerol moiety, whereas palmitic acid was a minor componentat both positions. In digalactosyl diacylglycerol and sulfoquinovosyldiacylglycerol, icosapentaenoic and palmitic acids were almostexclusively distributed at the sn-1 and sn-2 positions, respectively.In phosphatidylglycerol, palmitic and trans--13-hexadecenoicacid were exclusively located at the sn-2 position. In phosphatidylcholine,icosapentaenoic acid occurred in both the sn-l and sn-2 positions,whereas palmitic acid was confined to the sn-1 position. Itis suggested that monogalactosyl diacylglycerol in P. yezoensissynthesized in both the cytoplasmic and chloroplastic pathways,while the diacylglycerol moieties of the other chloroplast lipidsare virtually all derived from the chloroplastic pathway. (Received March 7, 1986; Accepted April 6, 1987)     

Distribution of Diacylglycerylhydroxymethyltrimethyl-{beta}-alanine (DGTA) and Phosphatidylcholine in Brown Algae

Lipids were analyzed in thirteen species of brown algae collectedat the seashore near Tokyo, Japan. Diacylglycerylhydroxymethyltrimethyl-ß-alanine(DGTA), a recently identified betaine lipid, was found as amajor lipid component in eight species of brown algae examined,namely, Ishige okamurai, Dictyota dichotoma, Pachydictyon coriaceum,Padina arborescens, Hizikia fusiformis, Sargassum horneri, S.ringgoldianum and S. thunbergii. However, phosphatidylcholine(PC) was not detected in any of these algae except I. okamurai.By contrast, PC was found as a major lipid component in fiveother species, namely, Colpomenia sinuosa, Endarachne binghamiae,Scytosiphon lomentarius, Eisenia bicyclis, Undaria pinnatifida.These algae in turn did not contain detectable amounts of DGTA.The fatty acid composition of four selected species, S. lomentarius,U. pinnatifida, D. dichotoma and H. fusiformis, was also studied.The fatty acid components of DGTA in D. dichotoma and H. fusiformiswere similar to those of PC in U. pinnatifida, the major componentsbeing 16:0, 18:2 and 20:46 (also 16:1 in D. dichotoma). (Received December 14, 1990; Accepted April 10, 1991)     

Content of arachidonic and eicosapentaenoic acids in polar lipids from Gracilaria (Gracilariales,Rhodophyta)

Fatty acid composition, especially the distribution of eicosapolyenoic acids in several species of Gracilaria, was analyzed in relation to their taxonomy. The species have been grouped into two types based on distribution of these polyenoic acids: Type 1, which contains palmitic, oleic and arachidonic acids as the major components, and Type II, which contains eicosapentaenoic acid in addition to Type I fatty acids. Octadecapolyenoic acids were detected only in trace amounts in each Type. A similar remarkable difference also was observed in the fatty acid composition of lipid classes. The major component of eicosapolyenoic acids in Type I was arachidonic acid in all lipid classes. In Type II, eicosapentaenoic acid was the major component in monogalactosyl diacylglycerol, digalactosyl diacylglycerol, sulfoquinovosyl diacylglycerol and phosphatidylglycerol. Arachidonic and eicosapentaenoic acids were contained in large amounts in Type II phosphatidylcholine. Grouping of Gracilaria species into Type I and Type II is not entirely consistent with morphological and taxonomic features, but the difference in fatty acid composition is likely due to genetic rather than to environmental factors.     

Characterization of Sulfoquinovosyl Diacylglycerol from Marine Red Algae

Sulfoquinovosyl diacylglycerol (SQDG) from a red alga, Gracilariaverrucosa, contained high levels of saturated fatty acids, palmiticand myristic acids. The lipid was separated by normal-phasethin-layer chromatography (TLC) into two spots which differedin terms of the color generated by the anthron reagent and interms of constituent fatty acids. However, chromato-graphicand spectrometric (NMR and IR) analyses indicated that boththe upper and the lower fractions were SQDG. The upper fractionwas mainly composed of 20:4/16:0 species, while the major speciesin the lower fraction was mainly 14:0/16:0 and 16:0/16:0. Comparisonof mobilities of SQDG from various sources by TLC confirmedthat the chain length of acyl groups significantly affectedthe Rf value. The short-chain saturated acid species of SQDGwas also detected in marine red algae, Gracilaria textorii,Gelidium amansii, Chondrus ocellatus and Chon-dria crassicaulis. (Received December 9, 1988; Accepted May 10, 1989)