1998 Fiscal Year Final Research Report Summary
Development of Intense Optical Tweezers for Application to Internal Structural Analysis of Living Cells
| Project/Area Number |
08559015
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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 | 展開研究 |
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| Research Field |
広領域
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| Research Institution | Grant-in-Aid for Scientific Research (A) |
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Principal Investigator |
TASHIRO Hideo Riken, Chirf Seientist, Director of Advanced Engineering Center, 工学基盤研究部, 基盤研究部長 (90124370)
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| Co-Investigator(Kenkyū-buntansha) |
YANAI Masaru Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Lectrrer, 医学部, 講師 (00210287)
KURACHI Masashi Department of Molecular and Cellular Neurobiology, Gunma University School of Medicine, Associate Professor, 医学部, 助手 (20271546)
WADA Satoshi RIKEN, Advanced Engineering Center, Research Scientist, 工学基盤研究部, 研究員 (90261164)
WADA Masamitsu Tokyo Metropolitan University, Faculty of Science, Professor, 理学部, 教授 (60011681)
NAKIO Satoshi Hitachi Metals Ltd. Magnetic and Electronic Materials Research, Director, 磁性材料研究所, 部長
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| Project Period (FY) |
1996 – 1998
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| Keywords | Optical Tweezers / Cellular Structure / Neutuophil |
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| Research Abstract |
In order to increase the trapping forces of optical tweezers, tunable Ti : Sapphire and Cr. LiSAF lasers were developed and it was found that Donut patter beam profile obtained with a combination of two identical lasers was effective. The following application of optical tweezers was carried out. For the direct investigation of intranuclear dynamics, extremely deformed nuclei of basipetally centrifuged protonemal cells were manipulated by the laser trap. It was concluded that a shortening force was existing in the chromatin of the NT and that probably no physical link existed between the chromatin and the nuclear envelop. To investigate the mechanisms underlying pseudopod protrusion in locomoting neutrophils, we measured the intracellular stiffness and viscosity in the leading region, main body, and trailing region from displacements of oscillating intracellular granules driven with an optical trap. We found 1) in the body and trailing region, the granules divided into a "fixed" population and a "free" population. 2) In the body and trailing region, there was no difference in stiffness or viscosity, but both were sharply lower in the leading region. To investigate their stabilization mechanism, we transected the exposed microtubules by laser microbeam irradiation and observed their length changes. Microtubules in neuritis were stabilized by 1) stopping disassembly at local sites including the plus ends, and 2) slowing disassembly along the length.
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