2006 Fiscal Year Final Research Report Summary
Stark Spectroscopy and Reaction Dynamics in a Single Cell
| Project/Area Number |
16072201
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | Hokkaido University |
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Principal Investigator |
OHTA Nobuhiro Hokkaido University, Research Institute for Electronic Science, Professor (70113529)
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| Co-Investigator(Kenkyū-buntansha) |
NAKABAYASHI Takakazu HOKKAIDO UNIVERSITY, Research Institute for Electronic Science, Associate Professor (30311195)
IIMORI Toshifumi HOKKAIDO UNIVERSITY, Research Institute for Electronic Science, Assistant Professor (60360947)
KINJO Masataka HOKKAIDO UNIVERSITY, Faculty of Advanced Life Science, Professor (70177971)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Single Living Cell / Fluorescence Lifetime Imaging / Electric Field Effect / Time-Resolved Emission / Cell Stress / Proton-Ion Concentration |
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| Research Abstract |
Fluorescence lifetime images of HeLa cells expressing GFP-tudor fusion protein have been continuously measured. The lifetime image displays a uniform distribution throughout cells; however, the cells exhibit the decrease in fluorescence lifetime after the treatment with serum-free medium and exposure to normal air. These results indicate that the fluorescence lifetime becomes shorter under the stress. The change in fluorescence lifetime in living cells has been attributed to a change in local electric field produced in the protein cavity surrounding the GFP chromophore. To investigate the electric field effects on the photoexcitation dynamics of GFP, field-induced change in fluorescence lifetime of GFP was measured in PVA, and the fluorescence lifetime of GFP is found to be reduced by an electric field, suggesting that the electric field produced inside the protein cavity affects the fluorescence lifetime of GFP.
The fluorescence lifetime images in HeLa cells as well as in Halobacterium salinarum loaded with BCECF have been measured with varying intracellular pH. The results indicate that intracellular pH of a living cell can be evaluated in vivo by fluorescence lifetime imaging (FLIM).
Aggregates of the halobacteria are effectively formed by an electric field, but the local fields in halosbacteria remain unchanged even after the formation of the aggregates.
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