2009 Fiscal Year Final Research Report
Studies for biosynthesis mechanism of natural chitin polymorphism
| Project/Area Number |
19380097
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
林産科学・木質工学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KIMURA Satoshi The University of Tokyo, 大学院・農学生命科学研究科, 助教 (00420224)
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| Co-Investigator(Kenkyū-buntansha) |
SAITO Yukie 東京大学, 大学院・農学生命科学研究科, 准教授 (30301120)
HORIUTI Hiroyuki 東京大学, 大学院・農学生命科学研究科, 准教授 (00209280)
WADA Wasahisa 東京大学, 大学院・農学生命科学研究科, 准教授 (40270897)
KUGA Shigenori 東京大学, 大学院・農学生命科学研究科, 教授 (60012051)
GOTO Taichitou 三重大学, 教育学部, 教授 (90183813)
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| Project Period (FY) |
2007 – 2009
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| Keywords | 天然キチン / α-キチン / β-キチン / Phaeocystis / ハオリムシ |
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| Research Abstract |
In the research, various chitin samples were collected and their structural analysis was achieved to understand a mechanism for biosynthesis of natural chitin polymorphs. Highly crystalline α-chitin obtained by mass cultivation of Phaeocystis enabled highly precise analysis of X-ray diffraction as well as solid-state NMR. The results lead to precise determination of αchitin unit cell. However, several minor signals which cannot be explained by the published model, suggesting possibility of larger unit cell. X-ray diffraction and electron microscopy analyses of crystalline β-chitin in tubes Lamellibrachia revealed that the microfibrils have a three dimensional orientation in the tube wall. This alignment can be ascribed to possible biosynthetic mechanism of this chitin, i.e. chitin-synthesizing enzymes travelling one-way, consistent with the motion of the worm body in the tube. The crystal transition between the dihydrate and anhydrous forms of β-chitin was also monitored by synchrotron X-ray diffraction under controlled relative humidity, the results revealed the crystal transition between the dihydrate and anhydrous forms was shown to take place reversibly through an intermediate structure, the monohydrate form, showing a large hysteresis.
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