1995 Fiscal Year Final Research Report Summary
Molecular level studies on biomineralization
| Project/Area Number |
05454504
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Functional basic dentistry
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| Research Institution | Nagasaki University |
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Principal Investigator |
KATSURA Nobuhiko Nagasaki University School of Dentistry Professor, 歯学部, 教授 (30013840)
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| Co-Investigator(Kenkyū-buntansha) |
KOBAYAKAWA Takeshi Nagasaki University School of Dentistry Res. Fel., 歯学部, 教務職員 (10153587)
ONO Toshio Nagasaki University School of Dentistry Res. Assoc., 歯学部, 助手 (80050607)
TANAKA Kiichiro Nagasaki University School of Dentistry Assoc. Prof., 歯学部, 助教授 (50001954)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Calcification / Collagen / Helical filament model / Biomineralization / Bone / Tendon / Plasma polymerized film repica method |
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| Research Abstract |
The images of the ultrastructure of bone and dentine obtained by the electron microscopic observation in which numerous crystallites of apatite are deposited in a densely packed collagen networks are accepted widely and fixed. Cracked specimens observed with an atomic force microscope (AFM) , however, did not show such images but only lamellar structure. Fibril feature observed accidentally might be an unmineralized collagen. Those unexpected observations suggest that collagen fiber is a sheet by nature and enforced us to observe agin tendon collagen fiber which is composed of Type I mostly and well oriented. The plasma polymerized film replica method which needs only dryness but not other drastic procedures was used. The tendon fiber shows that a sine-curved wavy surface with D-periodicity as well as AFM observation, and a pile of ultrathin flexible sheets. The edges of partially broken sheet have fibril-like feature. A side-view of cracked fiber by dryness shows an identical wavy surface as the top view. This means that the compoment element of fiber must be helical filament, and many helical filaments were observed in the calcifying aged hen tendon. A hierachical structure was posturated as follows : 1)helical filament with D-pitch composed by lateral assembly of dozens tropocollagen molecules, 2) wavy sheet of lateral assembly of the filaments, 3) pile of sheets transformable to a board, a column and tube with wavy surface. This helical filament model explains very well the characteristic banding, huge tensile strength, metabolism in mineralized region of collagen, and consists with "Nanospace Theory for Biomineralization" proposed by Katsura. "Hole zone" is not existent.
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