半滑舌鳎(Cynoglossus semilaevis

采用RT-PCR及RACE技术首次获得总长为1667bp的半滑舌鳎(Cynoglossus semilaevis)-淀粉酶(Amy)基因cDNA序列, 其开放阅读框为1539bp, 编码512个氨基酸, 已录入GenBank (登录号: KC122678)。同源性分析结果显示, 与斑点绿河豚(Tetraodon nigroviridis)、美洲拟鲽(Pseudopleuronectes americanus)等同源性较高(86%、83%)。采用邻接法构建系统进化树, 发现半滑舌鳎与点带石斑、鳜鱼等聚为一支。用分别添加0%、0.5%、1%、2%牛磺酸的微颗粒饲料投喂23日龄半滑舌鳎稚鱼28天, 采用相对定量法检测Amy基因表达水平。结果表明, 1%组和0.5%组显著高于0%组(P<0.05), 1%组与0%组差异极显著(P<0.01); 2%组与0%组无显著差异。上述结果表明, 半滑舌鳎稚鱼Amy基因表达受饲料中牛磺酸含量影响, 1%添加量作用显著。

MOLECULAR CLONING OF -AMYLASE GENE IN HALF SMOOTH TONGUE SOLE (CYNOGLOSSUS SEMILAEVIS GNTHER) AND ITS EXPRESSION IN RESPONSE TO DIETARY TAURINE

The -amylase gene (Amy gene) in Cynoglossus semilaevis was cloned in RT-PCR and RACE technique. Sequence analysis revealed a 1667bp full-length cDNA sequence containing 1539bp open reading frame (ORF) and this sequence encoded a 512 amino-acid polypeptide. Drthology analysis showed that the Amy gene of had a relatively high similarity with Tetraodon nigroviridis and Pseudopleuronectes americanus (86% and 83% respectively). Phylogenetic analysis using neighbor-joining method on amino acid sequence showed that the Amy gene was in the same category as those in teleosteans. C. semilaevis larvae (23dph) were fed for 28 days with mircodiets which contained different taurine levels (0%, 0.5%, 1%, 2%). Quantitative RT-PCR assay was used to estimate mRNA expression of Amy gene in response to dietary taurine. The Amy mRNA level of 1% treatment was extremely higher (P<0.01) than that of 0% and 2% treatments, and that of 0.5% treatment was significantly higher (P<0.05) than that of 0% and 2% treatments while there was no significant difference between 0% and 2% treatments. Therefore, these findings suggest that dietary taurine supplementation could affect the expression of Amy gene in C. semilaevis