Lipids of Chlamydomonas reinhardtii. Analysis of Molecular Species and Intracellular Site(s) of Biosynthesis

1988 Plant and Cell Physiology  
Membrane lipids of Chlamydomonas reinhardtii were separated into the major components, MGDG, DGDG, SQDG, DGTS, PG, PE, PI, and the molecular species of each lipid were isolated and analyzed. The fatty acid composition was determined for the total lipid, the particular lipid classes and the molecular species. The positional distribution of fatty acids between the C-l and C-2 position of the glycerol moiety was also determined. MGDG, DGDG, SQDG, PG and probably PI were found to be of plastidic
more » ... okaryotic) origin, while DGTS and PE were found to be of cytoplasmic (eukaryotic) origin. Prokaryotic lipids mainly contained 18:3(9,12,15), 18:2,16:4 and 16:3, while DGTS and PE were rich in 18:3(5,9,12), 18:4(5,9,12,15), 18:2 and 18:1(11) fatty acids. From the fact that each lipid class was characterized by an individual pattern of molecular species, we conclude that during their biosynthesis, all the lipids act individually as substrates for the lipid-linked desaturation of fatty acids. Moreover, our results suggest that in Chlamydomonas, 18:3(5,9,12) and 18:4(5,9,12,15) are formed in the cytoplasm using DGTS and PE as substrates.
doi:10.1093/oxfordjournals.pcp.a077533 fatcat:pcsf3jfltjg4ridtzrqsv35sxq