Roenneberg T
Institut für Medizinische Psychologie, Ludwig-Maximilians-Universität, München, Germany.
Ciba Found Symp. 1995;183:117-27; discussion 128-33. doi: 10.1002/9780470514597.ch7.
The circadian system of the marine unicellular alga Gonyaulax polyedra consists of at least two separate circadian oscillators. One of these controls the rhythm of bioluminescence, the other the rhythm of swimming behaviour. These two oscillators have separate light input mechanisms. The bioluminescence oscillator responds mainly to blue light whereas the aggregation oscillator is also sensitive to red light. Therefore, one of the chlorophylls is a likely candidate for the light receptor of the aggregation oscillator. Owing to their differences in spectral sensitivity, the two oscillators can be internally desynchronized when frequent dark pulses (e.g., five minutes every 20 min) are given in otherwise constant red light. Single bright red light pulses interrupting a constant dim blue background shift the bioluminescence oscillator similarly to dark pulses. They also lead to aftereffects in the period of the bioluminescence rhythm, indicating that the aggregation oscillator has a different phase response to red light pulses. In contrast, blue light pulses interrupting a dim red background shift both oscillators in a similar way and do not significantly alter the circadian period following the light pulse. The mammalian phosphagen creatine shortens the period of the bioluminescence rhythm significantly in blue light but not in red. Because it also increases the sensitivity of the phase response of the bioluminescence oscillator, we propose that creatine acts on its blue-sensitive light input mechanism.
海洋单细胞藻类多甲藻（Gonyaulax polyedra）的昼夜节律系统至少由两个独立的昼夜振荡器组成。其中一个控制生物发光节律，另一个控制游泳行为节律。这两个振荡器具有独立的光输入机制。生物发光振荡器主要对蓝光作出反应，而聚集振荡器对红光也敏感。因此，叶绿素之一很可能是聚集振荡器的光受体。由于它们在光谱敏感性上的差异，当在其他条件均为恒定红光的情况下频繁给予暗脉冲（例如，每20分钟5分钟）时，这两个振荡器可能会在内部发生不同步。单个明亮的红光脉冲打断恒定的暗蓝色背景，会使生物发光振荡器发生类似于暗脉冲的偏移。它们还会导致生物发光节律周期出现后效应，表明聚集振荡器对红光脉冲具有不同的相位响应。相比之下，打断暗红色背景的蓝光脉冲会以类似的方式使两个振荡器发生偏移，并且在光脉冲之后不会显著改变昼夜节律周期。哺乳动物磷酸原肌酸在蓝光下会显著缩短生物发光节律的周期，但在红光下则不会。由于它还会增加生物发光振荡器相位响应的敏感性，我们提出肌酸作用于其对蓝光敏感的光输入机制。
