ISSN:
1432-1351
Keywords:
Circadian rhythm
;
Paramecium bursaria
;
Contractile vacuole
;
Membrane potential
;
Membrane resistance
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract Paramecium bursaria shows a circadian rhythm of photoaccumulation: photoaccumulation is stronger during the day than at night. We obtained five strains of P. bursaria having different circadian periods under continuous light conditions, ranging from 20.9 to 27.9 h. Various physiological activities were compared in the cells of these strains. The periods of contractile vacuole contraction were in the range 10–15 s, which was almost proportional to the periods of the circadian rhythm in each strain. Swimming velocities were inversely proportional to the circadian period; i.e. swimming velocities were high in strains whose circadian periods were short. Resting membrane potential was more depolarized in strains with longer circadian periods. Finally, the membrane resistance of the resting state was reduced in proportion to the increase of the circadian period. Such correlation between the cellular properties and the circadian period suggests that the circadian clock mechanism is associated with various physiological activities of the cell.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00191848
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