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Reappraisal of the connective-tissue catch hypothesis in echinoderms.

重新评估棘皮动物结缔组织捕获假说。

基本信息

批准号：
11640685
负责人：
TAKAHASHI Keiichi
金额：
$ 2.24万
依托单位：
International Christian University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640685/
关键词：
connective-tissue catch collagen connective tissue echinoderm sea urchin BDM mechanical properties myosin

项目摘要

The catch apparatus (CA) is a collagenous ligament that surrounds the joint at the base of each spine of the sea urchin. A classic example of mutable connective tissue, it can change its mechanical properties quickly and reversibly. The precise mechanism of the response is unknown, but it is generally thought to involve the ground substances between the collagen fibrils. The CA contains muscle fibres but their contribution to the mechanical properties of the CA has been thought insignificant because they were so few. Nevertheless, a model has recently been proposed that assumes a major role for these muscle fibres in the behavior of the CA.The validity of the model is controversial, and we thought it was necessary to re-investigate the physiology of the CA, focusing our attention on the role of the muscle fibres. We found that 2,3-butanedione monoxime (BDM), a known inhibitor of myosin crossbridges, reversibly inhibits 'catch' and relaxes a stiffened CA of Anthocidaris crassispina at concentrations that block contraction of the spine muscle. In preliminary experiments, BDM had no effect on the mechanical properties of the central ligament of the spine of Diadema setosum which has been known to contain no muscle fibres. Our results indicate that the 'catch' in the CA of Anthocidaris depends on the activity of myosin in the muscle fibres. We discuss a model for the catch mechanism in the CA.

捕获装置（CA）是一种胶原韧带，围绕着海胆每个脊柱底部的关节。它是可变结缔组织的典型例子，它可以快速且可逆地改变其机械特性。该反应的确切机制尚不清楚，但通常认为涉及胶原纤维之间的基质。 CA 含有肌纤维，但它们对 CA 机械性能的贡献被认为是微不足道的，因为它们太少了。尽管如此，最近提出了一个模型，假设这些肌纤维在 CA 的行为中起主要作用。该模型的有效性存在争议，我们认为有必要重新研究 CA 的生理学，将我们的注意力集中在肌纤维的作用上。我们发现，2,3-丁二酮单肟 (BDM) 是一种已知的肌球蛋白横桥抑制剂，在阻止脊柱肌肉收缩的浓度下，可逆地抑制“捕获”并松弛 Anthocidaris crassispina 僵硬的 CA。在初步实验中，BDM 对 Diadema setosum 脊柱中央韧带的机械性能没有影响，已知该韧带不含肌肉纤维。我们的结果表明，Anthocidaris CA 的“捕获”取决于肌纤维中肌球蛋白的活性。我们讨论 CA 中捕获机制的模型。