| Project/Area Number |
08558075
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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 |
Biophysics
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| Research Institution | Osaka University (1997)
The University of Tokyo (1996) |
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Principal Investigator |
SAKO Yasushi Medical School, Assistant Prof., 医学部, 助手 (20215700)
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| Co-Investigator(Kenkyū-buntansha) |
HORIGUCHI Chiyoharu Hamamatsu Photonics KK.Chief, 主任研究員
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥8,900,000 (Direct Cost: ¥8,900,000)
Fiscal Year 1997: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1996: ¥6,900,000 (Direct Cost: ¥6,900,000)
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| Keywords | membrane proteins / membrane skeleton / cytoskeleton / Brownian diffusion / quadramut photodiode / 光学顕微鏡 / 変位計測 / 振動計測 / 細胞膜 / 膜タンパク質 |
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| Research Abstract |
A new-type super-sensitive position detector was developed using a quadrant avalanche photodiode (4APD) as the photo sensor. This position detector was interfaced to a newly-developed reflective polarisation optical microscope with a near-JR (810 nm) external cavity diode Laser as the light source, In this system, temperature and voltage of 4APD can be optimised to achieve maximum S/N ratio.
Using colloidal gold particles with a diameter of 10-100 nm as standard samples, 0.5-2 V output signal with>100 S/N was obtained. At this range of signal intensity, bandwidth of position measurement was 0-17 MHz (-3dB).
Spatial resolution of the system was examined by moving the standard sample by a PZT stage. At 375x magnification of the microscope, spatial resolution better than 3 nm was achieved. At this time, the spatial resolution is determined by a fluctuation of the power supply, and using more stable power supply, it should be improved to more than 1 nm. Movement within a 200 nm-phi area can be traced.
Using this system, lateral movement of plasma membrane proteins were measured. Although membrane proteins which is bound to the cytoskeleton was undetectable in 33 ms video-rate time window, rapid and Browninan diffusion movement restricted within an area of 300-500 nm was observed by more than 1 ms time resolution of the newly developed position detector. Such restricted movement of cytoskeleton-bound proteins suggests flexibility of the cytoskeletal filaments.
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