Lloyd David, Murray Douglas B
Microbiology, School of Biosciences, Cardiff University, Wales, UK.
Bioessays. 2007 May;29(5):465-73. doi: 10.1002/bies.20575.
Ultradian rhythms are those that cycle many times in a day and are therefore measured in hours, minutes, seconds or even fractions of a second. In yeasts and protists, a temperature-compensated clock with a period of about an hour (30-90 minutes) provides the time base upon which all central processes are synchronized. A 40-minute clock in yeast times metabolic, respiratory and transcriptional processes, and controls cell division cycle progression. This system has at its core a redox cycle involving NAD(P)H and dithiol-disulfide interconversions. It provides an archetype for biological time keeping on longer time scales (e.g. the daily cycles driven by circadian clocks) and underpins these rhythms, which cannot be understood in isolation. Ultradian rhythms are the foundation upon which the coherent functioning of the organism depends.
超日节律是指在一天内循环多次的节律，因此以小时、分钟、秒甚至几分之一秒来衡量。在酵母和原生生物中，一个周期约为一小时（30 - 90分钟）的温度补偿时钟提供了一个时间基准，所有核心过程都在此基准上同步。酵母中的一个40分钟时钟调节代谢、呼吸和转录过程，并控制细胞分裂周期进程。该系统的核心是一个涉及NAD(P)H和二硫醇 - 二硫化物相互转化的氧化还原循环。它为更长时间尺度上的生物计时（例如由生物钟驱动的每日周期）提供了一个原型，并支撑着这些不能孤立理解的节律。超日节律是生物体协调运作所依赖的基础。
