Kippert F, Lloyd D
Microbiology Group (PABIO), University of Wales College of Cardiff, UK.
Microbiology (Reading). 1995 Apr;141 ( Pt 4):883-90. doi: 10.1099/13500872-141-4-883.
An ultradian oscillation is described for Schizosaccharomyces pombe which meets the criteria for a cellular clock, i.e. timekeeping device. The rhythm can be induced by transfer from circadian conditions (stationary phase or very slow growth) to ultradian conditions (rapid growth). It can also be synchronized by ultradian temperature cycles of 6 degrees C difference. Released to constant temperature, the rhythm persists for 20 h without damping. The period of the free-running rhythm is temperature-compensated and in no experiment did period length fall outside the narrow range between 40 and 44 min. The parameter observed is the septum index, i.e. the percentage of cells occupying the last stage of the cell cycle in wild-type cells before final division. The results suggest control of the cell division processes by the ultradian clock.
裂殖酵母存在一种超日振荡，其符合细胞时钟（即计时装置）的标准。这种节律可通过从昼夜节律条件（静止期或非常缓慢的生长）转变为超日节律条件（快速生长）来诱导产生。它也可被相差6摄氏度的超日温度循环同步。在恒定温度下，该节律持续20小时且无衰减。自由运行节律的周期具有温度补偿性，在任何实验中，周期长度都未超出40至44分钟的狭窄范围。所观察的参数是隔膜指数，即在野生型细胞最终分裂前占据细胞周期最后阶段的细胞百分比。结果表明超日时钟对细胞分裂过程具有调控作用。
