title: Light Intensity Regulates LC-PUFA Incorporation into Lipids of Pavlova lutheri and the Final Desaturase and Elongase Activities Involved in Their Biosynthesis.
abstract: The microalga Pavlova lutheri is a candidate for the production of omega-3 long-chain polyunsaturated fatty acid (LC-PUFA), due to its ability to accumulate both eicosapentaenoic (EPA) and docosahexaenoic acids. Outstanding questions need to be solved to understand the complexity of n-3 LC-PUFA synthesis and partitioning into lipids, especially its metabolic regulation, and which enzymes and/or abiotic factors control their biosynthesis. In this study, the radioactivity of14C-labeled arachidonic acid incorporated into the total lipids of P. lutheri grown under different light intensities and its conversion into labeled LC-PUFA were monitored. The results highlighted for the first time the light-dependent incorporation of LC-PUFA into lipids and the light-dependent activity of the final desaturation and elongation steps required to synthesize and accumulate n-3 C20/C22 LC-PUFA. The incorporation of arachidonic acid into lipids under low light and the related Δ17-desaturation activity measured explain the variations in fatty acid profile of P. lutheri, especially the accumulation of n-3 LC-PUFA such as EPA under low light conditions.
authors.affiliation: Botany and Plant Science, School of Natural Sciences, Ryan Institute, National University of Ireland Galway , Galway, County of Galway, Ireland.
authors.forename: Freddy
authors.initials: F
authors.lastname: Guihéneuf
authors.affiliation: PRES LUNAM, Université du Maine, Institut Universitaire Mer et Littoral FR-3473 CNRS, EA 2160 Mer Molécules Santé, UFR Sciences et Techniques, 72085 Le Mans Cedex, France.|IUT Génie Biologique, 53020 Laval Cedex, Pays de la Loire, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Mimouni
authors.affiliation: PRES LUNAM, Université du Maine, Institut Universitaire Mer et Littoral FR-3473 CNRS, EA 2160 Mer Molécules Santé, UFR Sciences et Techniques, 72085 Le Mans Cedex, France.
authors.forename: Gérard
authors.initials: G
authors.lastname: Tremblin
authors.affiliation: PRES LUNAM, Université du Maine, Institut Universitaire Mer et Littoral FR-3473 CNRS, EA 2160 Mer Molécules Santé, UFR Sciences et Techniques, 72085 Le Mans Cedex, France.|IUT Génie Biologique, 53020 Laval Cedex, Pays de la Loire, France.
authors.forename: Lionel
authors.initials: L
authors.lastname: Ulmann
keywords: LC-PUFA incorporation; Pavlova lutheri; in vivo 14C-labeling; light intensity; marine microalga; n-3 LC-PUFA biosynthesis; Δ17-desaturation