2018 Fiscal Year Final Research Report
Visualization on the distribution of nucreic acids in yeast nucleus by using coherent X-ray diffraction
| Project/Area Number |
16H02218
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biological physics/Chemical physics/Soft matter physics
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| Research Institution | Keio University |
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Principal Investigator |
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Keywords | Ｘ線回折イメージング / 放射光 / Ｘ線自由電子レーザー / 低温Ｘ線回折実験 / 位相回復 / 三次元再構成 / 細胞核 / 細胞非侵襲イメージング |
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| Outline of Final Research Achievements |
In this project, we improved fundamental techniques including automatic control procedures of diffraction apparatuses, preparation of frozen-hydrated biological specimens, and measurement of spatial coherence of X-ray beam, in cryogenic X-ray diffraction imaging tomography using synchrotron X-rays and cryogenic X-ray diffraction using X-ray free electron laser pulses. In addition, we developed methods to obtain reliable electron density maps in phase retrieval calculation in structure analyses including the utilization of manifold learning. Based on these developments, we successfully established X-ray diffraction imaging technique for non-crystalline biological specimens, such as cells and organelles, through the visualization of common structures in yeast nucleus and cyanobacterium cell as well as the three-dimensional structures of yeast and bacteria cells without sectioning and chemical labeling necessary in other imaging techniques.
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| Free Research Field |
生物物理学
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| Academic Significance and Societal Importance of the Research Achievements |
低温X線回折イメージング・トモグラフィー実験では、細胞個々の特性や細胞周期に応じた物質分布の変化を、一方、XFELを用いるX線回折イメージング実験では、大量の細胞試料の投影電子密度を得ることが可能となった。本課題の研究成果は、シンクロトロン放射光とＸ線自由電子レーザーを相補的利用によって、細胞の個性と多様性を見ることにつながり、他のイメージング手法では成しえない非侵襲的イメージングの大きな進展につながることが期待できる。今後、本手法が細胞イメージングの重要な柱の一つとなるだけでなく、非結晶金属ナノ材料試料の構造研究にも裾野を広げていくと期待できる。
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