1992 Fiscal Year Final Research Report Summary
INTERCATION BETWEEN SYSTEMS OF ENERGY TRANSFER AND SIGNAL TRANSDUCTION IN THE CIRCADIAN CLOCK SYSTEM IN PARAMECIUM
| Project/Area Number |
02680223
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
生物物性学
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| Research Institution | SCHOOL OF MEDICINE, KITASATO UNIVERSITY |
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Principal Investigator |
HASEGAWA Kenji SCHOOL OF MEDICINE, KITASATO UNIVERSITY, ASSISTANT PROFESSOR, 医学部, 講師 (80050558)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Circadian clock / Paramecium / Behavior / cAMP / Resting potential / ATP / Mitochondria / Protein kinase A |
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| Research Abstract |
In Paramecium, we have measured that : 1) an isolated cell swims fast and straightforwardly during the day time and slowly turning frequently at night in a light/dark regimen (LD, L:D = 12:12), and this daily behavioral characteristics is sustained in constant darkness (DD) ; 2) the intracellular concentration of cAMP is highest at around midday and lowest at around midnight, and this oscillatory nature is maintained in DD ; 3) the resting potential of the cell membrane is clearly demonstrated to be more negative during the day time than at night ; 4) the intracellular concentration of potassium ion is low during the day time and high at night, this characteristic change is continued in DD ; 5) many mitochondria are globe-shaped during the day time and elongated at night, indicating that the ATP production is more active during the day time than at night ; and changes in protein kineses A and C almost parallel that of cAMP. Recently adenylate cyclase has been reported to function not only as an enzyme of cAMP-production but also as a potassium channel. The passage of K^+ through the channel in adenylate cyclase stimulates cAMP production. From this fact and our observations, a close loop described as : might play an important role on forming an autonomous oscillation, which drives circadian changes in resting membrane state, behavior, and cAMP production.
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