| Project/Area Number |
11650930
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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 |
高分子構造・物性(含繊維)
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
HIRAI Asako Kyoto University, Institute for Chemical Research, Associate Instructor, 化学研究科, 教務職員 (20156623)
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| Co-Investigator(Kenkyū-buntansha) |
TSUJI Masaki Kyoto University, Institute for Chemical Research, Associate Professor, 化学研究科, 助教授 (60172003)
HORII Fumitaka Kyoto University, Institute for Chemical Research, Professor, 化学研究科, 教授 (70124758)
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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 |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1999: ¥3,100,000 (Direct Cost: ¥3,100,000)
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| Keywords | Acetobacter xylinum / cellulose / nano-spinning / video microscopy system / optical microscope / transmission electron microscope / Normarski DIC set / electron diffraction / 固体高分解能NMR |
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| Research Abstract |
In this paper we tried to directly observe nano-spinning process of cellulose produced by Acetobacter xylinum. The results obtained are as given below.
1. Nano-spinning process of the ribbon-like cellulose assembly with a width of about 50 nm produced by a living bacterium was visualized by a video microscopy system. This system is composed of a differential interference contrast microscope, a CCD camera, an image processor, a video monitor, and a videocassette recorder. The spinning speed measured for a bacterium from rough colony was 3.4 μm/min, and that from smooth colony was 2.4 μm/min. This difference in spinning speed may be one of the reasons why high-order structures of cellulose produced by two types of colonies are different.
2. Dense and coarse band-like cellulose assemblies which consist of many strands were produced at 4 ℃, using smooth colonies isolated from Acetobacter xylinum ATCC 23769, whereas ribbon assemblies were produced by the same colonies at 28 ℃. The dense assembly gave crystalline reflections corresponding to the cellulose II type crystal in the selected-area electron diffraction (ED) experiment, while the coarse assembly did not give crystalline reflections under the same ED condition.
3. Never-dried ribbon assemblies were rapidly quenched in liquid propane (-179 ℃) and introduced into a TEM column by cryo-transfer. We tried to take images of ribbon assemblies with a cryo-TEM (JEOL JEM-4000SFX operated at 400kV). However, the vitreous ice embedding the assemblies was so thick that electron beams did not penetrate the samples. It is necessary to minimize the content of water in the samples. Further investigation is in progress.
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