Reappraisal of the connective-tissue catch hypothesis in echinoderms.
| Project/Area Number |
11640685
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
動物生理・代謝
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| Research Institution | International Christian University |
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Principal Investigator |
TAKAHASHI Keiichi International Christian University, Division of Natural Sciences, Professor, 理学研究科, 教授 (40011481)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | connective-tissue catch / collagen / connective tissue / echinoderm / sea urchin / BDM / mechanical properties / myosin |
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| Research Abstract |
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.
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Report
(3 results)
Research Products
(10 results)
