Chemical Structures and Functions of Neurpeptides in crustaceans

甲壳类动物神经肽的化学结构和功能

基本信息

批准号：
07456054
负责人：
NAGASAWA Hiromichi
金额：
$ 4.8万
依托单位：
Ocean Research Institute, The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

Seven molecular species of crustacean hyperglycemic hormone (CHH)-family peptides (Pej-SGP-I-VII), a red pigment concentrating hormone (RPCH), and two pigment dispersing hormones (PDHs) were isolated and their complete amino acid sequences determined. Like CHH-family peptides from other crustacean species, the seven CHH-family peptides consisted of 72-77 amino acid residues with six conserved Cys residues.Six peptides (Pej-SGP-I,II,III,V,VI and VII) showed hyperglycemic activity, when injected into eyestalk-ablated prawns, while Pej-SGP-IV exhibited inhibitory activity in the release of molting hormone (ecdysteroids) by the Y organ cultured in vitro. V and VI also showed a weak molt-inhibiting activity. These peptides were subjected to another assay to assess vitellogenesis-inhibiting activity, in which the effects of these peptides on the protein synthesis were examined by using pieces of developing ovary cultured in vitro. Six peptides with hyperglycemic activity showed inhibitory activity in the protein synthesis. The inhibition was not specific to only synthesis of vitellogenin, but that of all the proteins was inhibited.All the six peptides with hyperglycemic activity shared carboxyl-terminal amide structure. In order to clarify the impotance of this structure, we tried to synthesize a carboxyl-terminal free peptide by silkworm baculovirus expression system. Double-stranded DNAs encoding Pej-SGP-III and its analog with free carboxyl terminaus were chemically synthesized and inserted into virus DNA,which were injected into 5th instar larvae of the silkworm. But we could not detect any III or its analog in the hemolymph.The amino acid sequence of RPCH of this species was identical to that of other species thus far obtained. Two PDHs, with three different residues to each other, were equally potent in pigment dispersing activity. Erythrophore was most sensitive to these hormones, xanthophore and melanophore were less sensitive, and leucophore was least sensitive.

分离了甲壳动物高血糖激素 (CHH) 家族肽 (Pej-SGP-I-VII) 的七种分子、红色素浓缩激素 (RPCH) 和两种色素分散激素 (PDH)，并确定了它们的完整氨基酸序列。与其他甲壳类动物的 CHH 家族肽一样，7 个 CHH 家族肽由 72-77 个氨基酸残基和 6 个保守的 Cys 残基组成。 6 个肽（Pej-SGP-I、II、III、V、VI 和 VII）显示当注射到眼柄切除的虾体内时，具有高血糖活性，而 Pej-SGP-IV 在蜕皮激素（蜕皮类固醇）的释放中表现出抑制活性由体外培养的Y器官产生。 V和VI也表现出弱的蜕皮抑制活性。对这些肽进行另一种测定，以评估卵黄生成抑制活性，其中通过使用体外培养的发育中的卵巢碎片来检查这些肽对蛋白质合成的影响。六种具有高血糖活性的肽在蛋白质合成中表现出抑制活性。这种抑制不仅针对卵黄原蛋白的合成，而且所有蛋白质的合成都受到抑制。所有具有高血糖活性的六种肽均具有羧基末端酰胺结构。为了阐明该结构的重要性，我们尝试通过家蚕杆状病毒表达系统合成羧基末端游离肽。化学合成编码Pej-SGP-III及其类似物的带有游离羧基末端的双链DNA，插入病毒DNA中，注射入家蚕5龄幼虫体内。但血淋巴中未检测到任何III或其类似物。该物种的RPCH氨基酸序列与迄今为止获得的其他物种的氨基酸序列相同。两种具有三种不同残基的 PDH 在颜料分散活性方面具有同等效力。红细胞对这些激素最敏感，黄细胞和黑素细胞不太敏感，而白细胞最不敏感。