A Circadian Surface of Entrainment: Varying T, τ, and Photoperiod in Neurospora crassa
A Circadian Surface of Entrainment: Varying T, τ, and Photoperiod in Neurospora crassa
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DOI：
10.1177/0748730410379081
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发表时间：
2010-10-01
影响因子：
3.5
通讯作者：
Roenneberg, Till
中科院分区：
文献类型：
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作者：
Remi, Jan;Merrow, Martha;Roenneberg, Till
功能性昼夜节律系统的两个主要先决条件是内部日（昼夜节律周期）的生成以及根据外部日（时间周期）调整其长度和相位。昼夜节律周期的产生可以在生物体表现出自我维持、自由运行的节律的恒定条件下观察到。它们的表达取决于恒定条件的性质（例如，恒定黑暗，DD，或恒定光照，LL）。将昼夜节律周期长度（tau）与时间周期（T）同步的机制可以通过许多实验程序（例如单光脉冲）来探索，但只有在娱乐的情况下才能完全理解。当时钟稳定地夹带时，tau(LD) 平均等于 T，但时钟 (phi) 和 zeitgeber (Phi)（夹带相位，psi = Phi - phi）之间的相位关系取决于恒定条件下的 tau（tau(DD) 或 tau(LL)）与 T 之间的关系。夹带相位传统上是通过给定时钟的相位响应曲线 (PRC) 来预测的。时间刺激和 tau (DD)。但自然环境还有一个额外的性质，即光周期，它不容易纳入这种夹带范式中。因此，作者研究了粗糙脉孢菌中 162 种 T、tau 和光周期组合的夹带相，这有助于采用高通量方法。他们将不同的菌株（具有长、短和野生型自由运行期）引入不同的时间周期长度（16-26 小时）和光周期（每个周期的 16%-84%）。这些组合产生了具有高度系统化的夹带阶段的昼夜节律表面。结果表明，必须重新评估使用 PRC 和 tau(DD) 的传统夹带范式。
The two major prerequisites for a functional circadian system are the generation of an internal day (circadian cycle) and adjusting its length- and phase-to that of the external day (zeitgeber cycle). The generation of circadian cycles can be observed in constant conditions where organisms show a self-sustained, free-running rhythm. Their expression depends on the nature of the constant conditions (e. g., constant darkness, DD, or constant light, LL). The mechanism that synchronizes the circadian cycle length (tau) to that of the zeitgeber (T) can be explored by many experimental procedures (e. g., single light pulses), but it can only be fully understood under entertainment proper. When a clock is stably entrained, tau(LD) is, on average, equal to T, but the phase relationship between the clock (phi) and the zeitgeber (Phi) (phase of entrainment, psi = Phi - phi) depends on the relationship between tau in constant conditions (tau(DD) or tau(LL)) and T. Phase of entrainment has traditionally been predicted by the clock's phase response curve (PRC) for a given zeitgeber stimulus and tau(DD). But there is an additional quality of the natural environment-namely, photoperiod-which is not easily incorporated into this entrainment paradigm. The authors therefore investigated phase of entrainment for 162 combinations of T, tau, and photoperiod in Neurospora crassa, which lends itself to a high-throughput approach. They entrained different strains (with long, short, and wild-type free-running periods) to different cycle lengths of the zeitgeber (16-26 h) and photoperiods (16%-84% of each cycle). These combinations produce a circadian surface with highly systematic phases of entrainment. The results suggest that the traditional entrainment paradigms using the PRC and tau(DD) have to be reevaluated.