作　　者： ; ; ;

机构地区： 广西大学动物科学技术学院水产科学研究所

出　　处： 《中国水产科学》 2010年第6期1183-1191,共9页

摘　　要： 为了研究海水鱼合成高度不饱和脂肪酸(Highly unsaturated fatty acids,HUFAs)的关键酶,本研究克隆了军曹鱼(Rachycentron canadum)的△6脂肪酸去饱和酶的部分cDNA序列。根据GenBank已公布的其他鱼类的△6脂肪酸去饱和酶cDNA序列进行分析,设计了一对用于PCR扩增军曹鱼的△6脂肪酸去饱和酶基因保守序列的引物;然后以军曹鱼肝总RNA为模板,通过RT-PCR的方法扩增出一段长度为743bp的片段,该片段经纯化后,连接至pMD18-T载体上进行测序。结果显示,该片段与欧洲狼鲈(Dicentrarchus labrax)△6脂肪酸去饱和酶基因的覆盖区同源性为90.4%,该蛋白结构含有2个组氨酸保守区(HDFGH和HFQHH)和2个跨膜结构域,具有典型的△6脂肪酸去饱和酶结构特点。通过荧光定量PCR(Real-time quantityPCR,RTQ-PCR)检测该基因在军曹鱼幼鱼不同组织中的表达量,发现△6脂肪酸去饱和酶基因在军曹鱼脑的表达量最高;其次是肝;再其次是心、肠、脾、肾、鳃;而肌肉和皮肤的表达量相对较低,在脂肪组织中没有检测到△6去饱和酶基因的表达。结论为,军曹鱼具有合成HUFAs的关键酶—△6脂肪酸去饱和酶,在其所有组织中以脑之含量最多。 N-3 highly unsaturated fatty acids（HUFAs）,eicosapentaenoic（EPA） and docosahexaenoic acids（DHA）,are particularly important in the physiological procedures of human beings and animals.However,human and animals including some marine fish species can not synthesize HUFAs from linoleic and linolenic acids since they have no or less activity of delta 6nor 5 fatty acid desaturases and elongase that are a key for the synthesis of HUFAs.Therefore,they have to ingest HUFAs from their diets for the normal growth and development.Actually,this is a question that should be further explored in some marine fishes.Cobia（Rachycentron canadum） is a worldwide marine fish in tropical,subtropical and warm temperate seas.Cobia is an excellent candidate for aquaculture because of its fitting to wide salty,high resistance to diseases,and rapid growth,reaching 6-10 kg in 12-14 months.Marine fish is main source of HUFAs,DHA and EPA for human beings.With the decline of fishing and rapidly expanding aquaculture,feed-grade fishing has reached sustainable limits.A developing cobia commercial fishery needs to solve sustainable developing problems of artificial nutrition feed,using plant products to replace fish products,in which the basis of nutrition,physiology and biochemistry of cobia is necessary to study.Accordingly,delta 6 fatty acid desaturase,a key enzyme in the synthesis of HUFAs in cobia was studied in our experiments.Delta 6 fatty acid desaturase cDNA of cobia（Rachycentron canadum） was cloned and sequenced as well as its expression in different tissues was determined.Total RNA was extracted from the liver of juvenile cobia and amplified using real time-PCR（RT-PCR）.The amplified product was a fragment with 743bp.The sequence of the fragment of delta 6 fatty acid desaturase from cobia showed great identity（87%） with that of European seabass（Dicentrarchus labrax）.The protein sequence of the fragment included two transmembrane regions and two histidine boxes which were composite characteristics of a micros

关 键 词： 高度不饱和脂肪酸 脂肪酸去饱和酶 基因克隆 基因表达 荧光定量 军曹鱼

领　　域： [生物学]