Arachidic acid

All solvents used were of LC–MS analytical grade. Acetonitrile was purchased from Carlo Erba (Val De Reuil, France), isopropanol and methanol from Fisher Scientific (Laughborough, UK) and formic acid 98–100% from Chem-Lab (Zedelgem, Belgium). Lauric acid was purchased from Acros Organics (>99%), myristic acid from Sigma Aldrich (>99.5%), myristoleic acid from Sigma Aldrich (>99%), pentadecanoic acid from Sigma Aldrich (>99%), palmitic acid from Fluka (analytical standard), 9-palmitoleic acid from Fluka (analytical standard), margaric acid from Sigma Aldrich (>98%), 10-Z-heptadecenoic acid from Cayman Chemical Company (>98%), stearic acid from Fluka (analytical standard), oleic acid from Fluka (analytical standard), linoleic acid from Sigma Aldrich (>99%), linolenic acid from Sigma Aldrich (>99%), arachidic acid from Cayman Chemical Company (>98%), bihomo-γ-linolenic acid from Cayman Chemical Company (>98%), arachidonic acid from Sigma Aldrich (>99), 5,8,11,14,17-cis-eicosapentanoic acid from Fluka (analytical standard), 7,10,13,16,19-cis-docosapentaenoic acid from Cayman Chemical Company (>98%), 4,7,10,13,16,19-cis-docosahexaenoic acid from Sigma Aldrich (>98%) and lignoceric acid from Cayman Chemical Company (>98%).

The culture media RPMI 1640, HEPES, gentamycin, and Albumax I were obtained from GIBCO Life Technologies (Thermo Fisher Scientific, Waltham, MA, USA). Glucose, sodium bicarbonate, and hypoxanthine were purchased from Millipore-Sigma (Burlington, MA, USA). Polyprenol, dolichol, polyprenal, and nor-dolichol mixtures of 13 to 21 isoprene units were obtained from Avanti Polar Lipids (Alabaster, AL, USA). The dolichyl phosphate mixture (14 to 18 isoprene units), all trans-polyprenol (9 isoprene units), and isopentenol were obtained from Isoprenoids LC (Tampa, FL, USA). The following chemicals were obtained from Cayman Chemicals (Ann Arbor, MI, USA): polyunsaturated fatty acid mixture (adrenic acid, arachidonic acid, dihomo-γ-linolenic acid, docosahexaenoic acid, docosapentaenoic acid, eicosapentaenoic acid, linoleic acid, α-linolenic acid, and γ-linolenic acid, stearidonic acid), saturated and monounsaturated fatty acid mixture (arachidic acid, lauric acid, lignoceric acid, myristic acid, nervonic acid, oleic acid, palmitic acid, palmitoleic acid, and stearic acid), and ubiquinone-10. Squalene, 2,3-oxidosqualene, cholesterol, β-carotene, menaquinone-4, α-tocopherol, phylloquinone (vitamin K1), retinal, retinoic acid, and retinol were purchase from Millipore-Sigma (St. Louis, MO, USA). Anhydrotetracycline was obtained from Cayman Chemical (Ann Arbor, MI, USA).