Ikegami Taro, Takeuchi Yuki, Hur Sung-Pyo, Takemura Akihiro
Department of Chemistry, Biology and Marine Science, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa 903-0213, Japan.
Department of Chemistry, Biology and Marine Science, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa 903-0213, Japan.
Mar Genomics. 2014 Apr;14:59-66. doi: 10.1016/j.margen.2013.11.007. Epub 2014 Jan 4.
The waxing and waning cycle of the moon is repeated at approximately 1-month intervals, and concomitant changes occur in the levels of moonlight and cueing signals detected by organisms on the earth. In the goldlined spinefoot Siganus guttatus, a spawner lunar-synchronized around the first quarter moon, periodic changes in moonlight are used to cue gonadal development and gamete release. Rearing of mature fish under artificial constant full moon and new moon conditions during the spawning season leads to disruption or delay of synchronous spawning around the predicted moon phase. Melatonin, an endogenous transducer of the environmental light/dark cycle, increases in the blood and in the pineal gland around the new moon period and decreases around the full moon period. In synchrony with melatonin fluctuation, melatonin receptor(s) mRNA abundance is higher during the new moon period than during the full moon. The melatonin/melatonin receptor system is likely affected by moonlight. Measurements of the expression patterns of clock genes in neural tissues demonstrate that Cryptochrome (Cry1 and Cry3) and Period (Per2) fluctuate with lunar periodicity, the former peaking in the medial part of the brain around the first quarter moon period, and the latter peaking in the pineal gland around the full moon. Some clock genes may respond to periodic changes in moon phase and appear to be involved in the generation of lunar-related rhythmicity in lunar spawners. Thus, some fish use moonlight-related periodicities as reliable information for synchronizing the timing of reproductive events.
月球的盈亏周期大约以1个月为间隔重复出现，与此同时，地球上生物体所检测到的月光水平和信号提示也会发生相应变化。在金线鱼（Siganus guttatus）中，这种产卵鱼类的繁殖活动与农历新月前后的月相同步，月光的周期性变化被用于提示性腺发育和配子释放。在繁殖季节，将成熟的金线鱼置于人工模拟的持续满月和新月条件下饲养，会导致在预测的月相附近出现同步产卵的中断或延迟。褪黑素是环境光/暗周期的内源性传导物质，在新月期间血液和松果体中的含量会增加，而在满月期间则会减少。与褪黑素的波动同步，褪黑素受体mRNA丰度在新月期间高于满月期间。褪黑素/褪黑素受体系统可能受到月光的影响。对神经组织中生物钟基因表达模式的测量表明，隐花色素（Cry1和Cry3）和周期蛋白（Per2）随月球周期波动，前者在农历上弦月期间在大脑中部达到峰值，后者在满月期间在松果体中达到峰值。一些生物钟基因可能对月相的周期性变化做出反应，并且似乎参与了月相产卵鱼类中与月球相关节律的产生。因此，一些鱼类利用与月光相关的周期性作为同步繁殖事件时间的可靠信息。
