Linoleic acid

The preparation of fatty acid methyl esters (FAMEs) and their analysis by gas chromatography (GC) was described previously 15) (link) . Total lipids of dried cells were transmethylated with 10％ methanolic HCl for 4 hours at 55℃. The resulting FAMEs were extracted using n-hexane, concentrated, and analysed by GC-2025 gas chromatography (Shimadzu, Japan) on a TC-70 capillary column (GL Science, Japan) . Fatty acid quantification was performed using linoleic acid (18:2ω6; Tokyo Chemical Industry, Japan) as an internal standard.

2-Nitrophenylhydrazine hydrochloride (2-NPH•HCl), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (1-EDC•HCl), butyric acid (FA4:0), hexanoic acid (FA6:0), heptanoic acid (FA7:0), octanoic acid (FA8:0), undecanoic acid (FA11:0), lauric acid (FA12:0), myristic acid (FA14:0), palmitic acid (FA16:0), heptadecanoic acid (margaric acid, FA17:0), stearic acid (FA18:0), nonadecanoic acid (FA19:0), arachidic acid (FA20:0), tricosanoic acid (FA23:0), linOleic acid (FA18:2), and linolenic acid (FA18:3) were purchased from Tokyo Chemical Industry Co., Ltd (Tokyo, Japan). Oleic acid (FA18:1), arachidonic acid (FA20:4), eicosapentaenoic acid (EPA, FA20:5) and docosahexaenoic acid (DHA, FA22:6) were obtained from Sigma-Aldrich Japan (Tokyo, Japan). Capric acid (FA10:0), and HPLC grade methanol and water were from Wako Pure Chemical Industry (Osaka, Japan). FA labeling reagents were obtained from YMC CO (Kyoto, Japan).