| Project/Area Number |
59440019
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
General anatomy (including Histology/Embryology)
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| Research Institution | Gunma University School of Medicine |
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Principal Investigator |
ISHIKAWA Harunori Gunma University School of Medicine, 医学部, 教授 (90010058)
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| Co-Investigator(Kenkyū-buntansha) |
SAITO Kogaku Gunma University College of Medical Care and Technology, 医療短期大学部, 教授 (50003398)
JINGUJI Youichi Gunma University School of Medicine, 医学部, 助手 (00114182)
FUJIMAKI Noboru Gunma University School of Medicine, 医学部, 講師 (10008261)
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| Project Period (FY) |
1984 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥27,000,000 (Direct Cost: ¥27,000,000)
Fiscal Year 1986: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1985: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1984: ¥24,000,000 (Direct Cost: ¥24,000,000)
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| Keywords | Actomyosin system / Actin filament / Cell motility / Ultrastructural analysis / Cytoskeleton / Plasmalemmal undercoat / Myofibril / ストレス線維 / 細胞極性 / 中間径フィラメント / 小腸上皮 / 血管内皮 |
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| Research Abstract |
Thin-section electron microscopy was used to examine the mode of association of actomyosin fibrous systems with the plasmalemma first in skeletal muscle. At the end of a muscle fiber, terminating actin filaments of a myofibril were seen to attach to the sarcolemma via a characteristic plasmalemmal undercoat. The filaments never penetrated the undercoat layer. The H-meromyosin decoration showed that all the terminating filaments were arranged with the arrowheads pointing away from the sarcolemma. From the observations most of such terminating actin filaments were considered to be longer than the I-band filaments of ordinary sarcomeres. Similar undercoats were found in small patches along the whole length of a muscle fiber. Intermediate filaments almost always were closely related with such undercoats. Clearly intermediate filaments are also associated with the sarcolemma via the plasmalemmal undercoat. In smooth muscle cells actin filaments reversed their polarity at the dense body to f
… More
orm a bidirectional arrangement in each bundle and attached to the sarcolemma via the undercoat called dense plaque. The degree of development of the contractile system in vascular smooth muscles seemed to be reflected on that of dense bodies and dense plaques and anti-alpha-actinin reactivity in immunofluorescence. The development of those structures varied in different types of arteries and veins.
The distribution and arrangements of actomyosin fibrous systems were also examined in various non-muscle tissue cells, especially in renal epithelial cells and vascular endothelial cells. The actin bundles running straight in the basal cytoplasm were identified as the stress fibers based on their ultrastructural characteristics. The mode of association of the stress fiber with the plasmalemma was basically similar to that in muscle cells. In osteoclasts there were contact zones which contained dense meshworks of actin filaments in the cytoplasm. Those actomyosin systems can be considered to play a role in cell adhesion on the extracellular matrix. Less
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