机构地区: 中山大学
出 处: 《动物学报》 2005年第1期108-116,共9页
摘 要: 本文以黄鳍鲷 (Sparuslatus)为研究对象 ,利用GeneRaceTM 技术 ,从其肝组织中克隆出类胰岛素生长因子 (IGF Ⅰ )cDNA ,并应用半定量RT PCR方法研究了半胱胺盐酸盐 (Cysteaminehydrochloride)和LHRH A对其肝组织IGF Ⅰ基因表达的影响。黄鳍鲷IGF ⅠcDNA全长为 84 0bp ,编码 185aa多肽 ;序列分析表明 ,黄鳍鲷IGF Ⅰ基因编码的氨基酸序列与金鱼的同源性为 75 8% ,与牙鲆的同源性为 86 5 % ,与同属鲷科的黑鲷同源性高达 10 0 % ,证明鱼类类胰岛素生长因子是非常保守的 ,E区域分析结果表明黄鳍鲷IGF Ⅰ属Ea 4型。在饲料中投喂CSH、LHRH A等添加剂 ,实验组黄鳍鲷鱼种的相对生长率、垂体GH含量、肝脏IGF ⅠmRNA水平均显著高于对照组。以上结果提示 :CSH、LHRH A能促进黄鳍鲷生长激素的合成和IGF Ⅰ基因的表达 。 This paper was focused on the effects of cysteamine (CSH) and luteininzing hormone-releasing hormone analog (LHRH-A, D-Ala6, Pro9-Net-LHRH) on the expression of IGF-Ⅰ mRNA and the growth in juvenile yellow-fin porgy Sparus latus.IGF-ⅠcDNA of yellow-fin porgy was cloned from the liver using GeneRacer IM kit (Invitrogen), The IGF-Ⅰ cDNA is 840 bp in length, and the open reading frame encodes a putative protein of 185 amino acids.The comparison of the deduced amino acid sequence indicated that yellow-fin porgy IGF-Ⅰshared 75.2% identity with zebrafish, 75.8% with goldfish, 84.7% with trout, 86.5% with turbot, 96.8% with grouper, and 100% with seabream.The analysis of the E domain showed that porgy IGF-Ⅰ belonged to type Ea-4.The experiments were conducted from August to October 2003 for 45 days and the effects of CSH and LHRH-A administered in the diet on GH, growth, IGF-Ⅰ mRNA were determined.Healthy juvenile yellow-fin porgy (body weight 8.9±2.5 g) were maintained in outdoor cages (15 m×1.5 m×1.2 m) in seawater under natural photoperiod.Water temperatures varied from 23 to 28 °C.and the dissolved oxygen, pH and salinity were around 6.0 mg/L, 8.0 and 10‰, respectively.After acclimation of two weeks, the yellow-fin porgy were randomly and equally allocated to cages and fed formulated diet twice a day to satiation.The IGF-ⅠmRNA expression in the liver was examined with semi-quantitative RT-PCR, and GH concentrations in the pituitary were assayed with heterogenous RIA.The results showed that CSH (1.25 mg/g diet) and LHRH-A (10 μg/g diet) alone or in combination significantly increased the pituitary GH contents and the hepatic IGF- I mRNA levels of yellow-fin porgy as compared to that of the control group at the end of the experiment, The relative somatic growth rates (RSGR) of yellow-fin porgy fed with CSH and LHRH-A alone or in combination for 45 days were significantly higher than those of the control group.The relative linear growth rates (RLGR) of yellow-fin porgy fed with CSH or the combin