Biosynthesis of arachidonic acid in the oleaginous microalga Parietochloris incisa (Chlorophyceae): Radiolabeling studies |
| |
Authors: | Chiara Bigogno Inna Khozin-Goldberg Daniel Adlerstein Zvi Cohen |
| |
Affiliation: | (1) The Laboratory for Microalgal Biotechnology, Albert Katz Department for Drylands Biotechnologies, Jacob Blaustein Institute for Desert Research, Sde-Boker Campus, 84990, Israel;(2) Department of Chemistry, Ben Gurion University of the Negev, Sde-Boker Campus, 84990, Israel |
| |
Abstract: | The fresh-water green alga Parietochloris incisa is the richest plant source of the PUFA arachidonic acid (20∶4n−6, AA). To elucidate the biosynthesis of AA in this alga
we labeled cultures of P. incisa with radioactive precursors. Pulse chase labeling with acetate resulted in its incorporation via the de novo biosynthesis pathway of FA. However, labeled acetate was also utilized for the elongation of C16 and C18 PUFA. Labeling with 1-14C]oleic acid has shown that the first steps of the lipid-linked FA desaturations utilize cytoplasmic lipids. PC and diacylglyceryltrimethylhomoserine
are the major lipids involved as acyl carriers for the Δ12 and Δ6 desaturations of oleic acid, leading sequentially to linoleic
and γ-linolenic acids. The latter is released from its lipid carrier and elongated to 20∶3n−6, which is reincorporated primarily
into PF and PC and finally desaturated to AA. Galactolipids, mostly monogalctosyldiacylglycerol (MGDG), serve as substrates
for the chloroplastic Δ12 desaturase and, apparently, the ω3 desaturation, common to higher plants and many green algae. The
predominant sequence desaturates the 18∶1/16∶0 molecular species of MGDG stepwise to the 18∶3n−3/16∶3n−3 molecular species
similar to the prokaryotic pathway of higher plants and green algae. |
| |
Keywords: | |
本文献已被 PubMed SpringerLink 等数据库收录! |
|