Mobilization of arachidonyl moieties from triacylglycerols into chloroplastic lipids following recovery from nitrogen starvation of the microalga Parietochloris incisa

Inna Khozin-Goldberg, Pushkar Shrestha, Zvi Cohen

    Research output: Contribution to journalArticlepeer-review

    120 Scopus citations

    Abstract

    The microalga Parietochloris incisa (Trebouxiophyceae, Chlorophyta) was isolated from an alpine environment. It was found to accumulate unusually high amounts of arachidonic acid (AA)-rich TAG. We have hypothesized that microalgal PUFA-rich TAG might have a role as a depot of PUFA, which could be mobilized for the construction of chloroplastic membranes under sudden changes in environmental conditions. We have thus studied the changes in lipid and fatty acid composition during recovery from nitrogen starvation at 24 and 12°C. At both temperatures, TAG was mainly consumed to support growth, however, there was a significant increase in the content of AA in the chloroplastic lipids, predominantly, monogalactosyldiacylglycerol (MGDG) at 24°C, but much less so at 12°C. Similar results were obtained using radiolabeled precursors. These and other findings point to the existence of three modes of operation for the construction of chloroplastic lipids that the alga can utilize to support growth under changing environmental conditions. When environmental conditions do not support growth, the prokaryotic pathway predominates. When sudden changes occur, the eukaryotic pathway is enhanced and can be even further augmented by influx of acyl moieties from TAG to maximize the exploitation of growth conditions that may possibly be transitory.

    Original languageEnglish
    Pages (from-to)63-71
    Number of pages9
    JournalBiochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
    Volume1738
    Issue number1-3
    DOIs
    StatePublished - 30 Dec 2005

    Keywords

    • Arachidonic acid
    • Microalgae
    • PUFA biosynthesis
    • Parietochloris incisa
    • Triacylglycerol

    ASJC Scopus subject areas

    • Molecular Biology
    • Cell Biology

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