Tokushima H, Okamoto K I, Miwa I, Nakaoka Y
Department of Biophysical Engineering, Faculty of Engineering Science, Osaka University, Japan.
J Comp Physiol A. 1994 Dec;175(6):767-72. doi: 10.1007/BF00191848.
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.
白天的光积累比夜晚更强。我们获得了五株在持续光照条件下具有不同昼夜周期的绿草履虫菌株，其昼夜周期范围为20.9至27.9小时。对这些菌株的细胞进行了各种生理活动的比较。收缩泡收缩的周期在10 - 15秒范围内，这几乎与每个菌株的昼夜节律周期成正比。游泳速度与昼夜周期成反比；即昼夜周期短的菌株游泳速度高。在昼夜周期较长的菌株中，静息膜电位更去极化。最后，静息状态的膜电阻随着昼夜周期的增加而按比例降低。细胞特性与昼夜周期之间的这种相关性表明，昼夜节律时钟机制与细胞的各种生理活动相关。
