.DELTA.-4 DESATURASES FROM EUGLENA GRACILIS， EXPRESSING PLANTS， AND OILS CONTAINING PUFA

The invention relates to an improved method for the specific production of unsaturated .omega.-3 fatty acids and a method for producing triglycerides containing an increased number of unsaturated fatty acids， especially .omega.3 fatty acids comprising more than three double bonds. Disclosed is the production of a transgenic organism， preferably a transgenic plant， or a transgenic microorganism containing an increased number of fatty acids， oils， or lipids comprising .DELTA.-4 double bonds as a result of a .DELTA.-4 desaturase being expressed from Euglena gracilis. The invention further relates to expression cassettes containing a nucleic acid sequence， a vector， and organisms containing at least one nucleic acid sequence or an expression cassette. Also disclosed are unsaturated fatty acids and triglycerides having an increased fatty acid content and the use thereof. Fatty acids and triglycerides are used in a plurality of application in the food industry， in animal nutrition， cosmetics， and pharmaceuticals and are suitable for many different applications depending on whether free saturated or unsaturated fatty acids or triglycerides having an increased saturated or unsaturated fatty acid content are used.本发明涉及不饱和ω-3脂肪酸（ω-3 fatty acids）的特异性制备改良方法，以及制备不饱和脂肪酸（尤其是含三个以上双键的ω-3脂肪酸）含量提升的甘油三酯的方法。本发明公开了一种转基因生物的制备方法：通过表达纤细裸藻（Euglena gracilis）来源的Δ4-去饱和酶（Δ4-desaturase），可获得富含含Δ4-双键的脂肪酸、油脂或脂质的转基因生物（优选转基因植物）或转基因微生物。本发明还涉及包含核酸序列的表达盒（expression cassette）、载体（vector），以及携带至少一种核酸序列或表达盒的生物。本发明同时公开了脂肪酸含量提升的不饱和脂肪酸与甘油三酯及其应用。脂肪酸与甘油三酯可应用于食品工业、动物营养、化妆品及制药等多个领域，其具体适用场景取决于所采用的是游离饱和/不饱和脂肪酸，还是饱和或不饱和脂肪酸含量提升的甘油三酯。