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Growth stimulation in abalone by salmon growth hormone and mechanism of its growth

鲑鱼生长激素刺激鲍鱼生长及其生长机制

基本信息

批准号：
12556033
负责人：
KAWAUCHI Hiroshi
金额：
$ 7.68万
依托单位：
KITASATO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

This study aimed to estimate the origin and evolution of the growth hormone (GH) family following the identification of the GH protein and cDNA in the early-evolved vertebrates, Chondrichthyes and Agnatha, and a GH-like protein or gene in an invertebrate, the abalone, and apply these findings to abalone aquaculture.The GH family is composed of GH, prolactin (PRL) and somatolactin (SL). We have isolated dogfish GH (183 residues) and lamprey GH (181 residues) from their pituitary glands and cloned their cDNAs. We did not, however, obtain evidences for the presence of PRL and SL in the lamprey. We have also cloned an insulin-like growth factor (IGF) cDNA from the lamprey liver and demonstrated a dose-dependent increase of its mRNA expression in the liver in vitro. Therefore, it is likely that the growth-acceleration mechanism through the GH and IGF axis was established in the early-evolved vertebrates, and that a GH gene was duplicated during the evolution of Agnatha and diversified into PRL and SL in the gnathostomes. We searched for a GH-like protein in invertebrates. Using an antibody to salmon GH, we found GH-immunopositive cells in the cerebral ganglia of abalone. From this tissue, we cloned a cDNA fragment by PCR with primers corresponding to the most conserved C-terminal region of GH. The deduced 44 amino acids sequence is highly similar to that of GH. This suggests that invertebrates may have a GH-like protein. We then looked at the effect of salmon GH on the growth of abalone. Juvenile abalone were fed with alginic acid-gel which contained salmon GH. After feeding with this gel, considerable levels of salmon GH were detected in the body fluids of the abalone. The shell length and weight of the abalone increased remarkably in comparison with the control animals. Thus, the salmon GH gel may be a potential a growth accelerating agent for the abalone.

本研究旨在通过鉴定早期进化脊椎动物软骨和无脊椎动物中的生长激素蛋白和基因，以及无脊椎动物鲍鱼中的生长激素样蛋白或基因，来探讨生长激素家族的起源和进化。生长激素家族由生长激素、催乳素(PRL)和生长激素(SL)组成。我们分离了角鱼生长激素(183个残基)和七鳃鳗生长激素(181个残基)，并克隆了它们的cDNA。然而，我们没有获得在七鳃鳗中存在催乳素和催乳素的证据。我们还从七鳃鳗肝脏中克隆了胰岛素样生长因子(IGF)基因，并证明其在体外肝脏中的mRNA表达呈剂量依赖性增加。因此，在早期进化的脊椎动物中可能建立了通过GH和IGF轴的生长加速机制，GH基因在无脊椎动物进化过程中被复制，并在颌口动物中分化为PRL和SL。我们在无脊椎动物中寻找一种类似生长激素的蛋白质。利用鲑鱼生长激素抗体，我们在鲍鱼的脑神经节内发现了生长激素免疫阳性细胞。从该组织中，我们用与生长激素最保守的C-末端区域相对应的引物，通过聚合酶链式反应，克隆了一个基因片段。推导的44个氨基酸序列与生长激素高度相似。这表明无脊椎动物可能有一种类似生长激素的蛋白质。然后我们观察了鲑鱼生长激素对鲍鱼生长的影响。用含有鲑鱼生长激素的海藻酸凝胶饲喂鲍鱼幼鱼。喂食这种凝胶后，在鲍鱼的体液中检测到相当数量的鲑鱼生长激素。与对照组相比，皱纹盘鲍的壳长和重量显著增加。因此，鲑鱼生长激素凝胶可能是一种潜在的鲍鱼生长促进剂。