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Molecular physiology on ion transport sytems in silkworms

蚕离子传输系统的分子生理学

基本信息

批准号：
06454069
负责人：
AZUMA Masaaki
金额：
$ 3.14万
依托单位：
Tottori University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06454069/
关键词：
silkworm midgut amino acid transport V-ATPase Potassium pump Proton pump silk gland Bombyx mori

项目摘要

Insect midgut in Lepidoptera (the main part of the alimentary canal) is a central and indispensable tissue to exchange various ionic solutes across the epithelia and to maintain the cellular activity and the tissue functions (s). We have investigated such a mechanism to understand the ionic homeostasis and osmoregulation in the silkworm system. Results ar as follows :(1) Immunocytochemical studies were done with the specific anitibody against V-ATPase. In silkwrms, V-ATPase can be detected in the midgut, the Malpighian tubules, the salivary gland and the silk gland. V-ATPase in each tissue was located at the cell surface, suggesting that silkworm V-ATPase is a plasma membrane-type not an endomenbrane-type.(2) In the silk gland, V-ATPase seems to contribute to produce an acidic milieu in the glandular lumen. This shows highly contrast to the midgut lumen, which produce an extremely high alkalinity (pH 11-12).(3) The silk gland V-ATPase is quite similar to other animal V-ATPases in the common subunits of V-ATPase.(4) K+/amino acid symporter in the midgut was rather labile protein and hard to purify. Its molecular nature still remains unknown.(5) The silk gland is highly active tissue for silk protein syntesis and secretion. This implies that the tissue needs much supply of amino acids from the haemolymph to synthesize the silk protein. Thus, it is coming up as the quite near future subject to survey the K+/amino acid symporter in the silk gland. This would be expected as the breakthrough for identifing the K+/symporter molecule (s).

昆虫中肠是鳞翅目昆虫消化道的主要部分，是昆虫上皮细胞间交换各种离子溶质，维持细胞活性和组织功能的中心组织。我们已经研究了这种机制，以了解家蚕系统中的离子稳态和代谢调节。结果如下：（1）用V-ATPase特异性抗体进行免疫细胞化学研究。在蚕的中肠、马氏管、唾液腺和丝腺中均可检测到V-ATPase。V-ATP酶在各组织中均定位于细胞表面，表明家蚕V-ATP酶为质膜型而非内膜型。(2)在丝腺中，V-ATPase似乎有助于在腺腔中产生酸性环境。这显示出与中肠腔的高度对比，中肠腔产生极高的碱度（pH 11-12）。(3)丝腺V-ATP酶与其它动物V-ATP酶的共同亚基十分相似。(4)中肠K+/氨基酸同向转运体是一种不稳定的蛋白质，纯化困难。它的分子性质仍然未知。(5)丝腺是合成和分泌丝蛋白的高度活跃组织。这意味着该组织需要血淋巴提供大量的氨基酸来合成丝蛋白。因此，研究丝腺K ~+/氨基酸同向转运体是一个很有前途的课题。这有望成为鉴定K+/同向转运体分子的突破口。