| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2003: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2002: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
From the cell membrane of Paramecium, we tried to isolate and purify the channel proteins whose activity is sensitive to temperature change. Although the purification was, yet incomplete, we found some chemicals that inhibit specifically thermosensory response of Paramecium. The inhibitors were lysozyme, ruthenium-red etc. These inhibitors are polyvalent cations in the neutral solution. From such nature of the inhibitors, following two possibilities are considered for the inhibitory mechanism ; (1) Inhibitors directly bind to the thermosensory channels to block ionic current. (2) Inhibitors indirectly bind to the negatively charged lipids surrounding thermosensory channels, which alters the membrane fluidity and inhibits the activity of channels. In order to test the possibility (2), we constructed the fluorescence microscope system that can measure the membrane fluidity of the living cells stained with fluorescent probe, laurdan. From P. aurelia group, we have already selected each species of high and low thermotolerance. Comparing the membrane fatty acid contents between these species, the high thermotolerant species have a decreased ratio of unsaturated to saturated fatty acids than the low thermotolerant species. Measurements of the membrane fluidity using the fluorescence microscope system showed that the high thermotolerant species had a decreased membrane fluidity from the low thermotolerant species. We will measure rapid changes of membrane fluidity in response to temperature change.
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