Sukenik, A., Schneider, J.C., Roessler, P.
Abstract:
Eicosapentaenoic acid (20:5n-3 - EPA) is the major polyunsaturated fatty acid found in the marine eustigmatophyte Nannochloropsis. Physiological and biochemical experiments provided solid data for development of a model of EPA synthesis in the alga. Recently a mutant Strain of Nannochloropsis that is completely devoid of EPA was isolated. An analysis of fatty acids from whole cells showed that the loss of EPA in the mutant strain was accompanied by an increase in the amount of arachidonic acid (20:4n-6 - AA). Molecular species analysis of mgDG showed that relatively to the wild type strain the mutant strain contains more 16:1/16:0 mgDG and exceptional high amount of mgDG species containing 20:4n-6 at the expense of EPA. Based on these observations it is concluded that the mutation affects an extrachloroplastic omega3 desaturase that is required for the synthesis of EPA from arachidonic acid.
(National Institute of Oceanography, P.O.Box 8030, Haifa 31080, Israel)