Instrument design and protocol for the study of light controlled processes in aquatic organisms, and its application to examine the effect of infrared light on zebrafish

The acquisition of reliable data strongly depends on experimental design. When studying the effects of light on processes such as behaviour and physiology it is crucial to maintain all environmental conditions constant apart from the one under study. Furthermore, the precise values of the environmental factors applied during the experiment should be known. Although seemingly obvious, these conditions are often not met when the effects of light are being studied. Here, we document and discuss the wavelengths and light intensities of natural and artificial light sources. We present standardised experimental protocols together with building plans of a custom made instrument designed to accurately control light and temperature for experiments using fresh water or marine species. Infrared light is commonly used for recording behaviour and in electrophysiological experiments although the properties of fish photoreceptors potentially allow detection into the far red. As an example of our experimental procedure we have applied our protocol and instrument to specifically test the impact of infrared light (840 nm) on the zebrafish circadian clock, which controls many aspects of behaviour, physiology and metabolism. We demonstrate that infrared light does not influence the zebrafish circadian clock. Our results help to provide a solid framework for the future study of light dependent processes in aquatic organisms.

可靠数据的获取极大程度上依赖于实验设计。在研究光对行为、生理等过程的影响时，至关重要的一点是除所研究的变量外，需保持其余所有环境条件恒定不变；此外，还需明确实验过程中所施加的各环境因子的精确取值。尽管这一点看似理所当然，但在开展光效应相关研究时，此类要求往往难以得到满足。本研究对天然光源与人工光源的波长及光强进行了记录与探讨，同时提供了标准化实验方案（standardised experimental protocols），以及一款可针对淡水或海洋生物实验精准调控光与温度的定制化实验装置的搭建图纸。尽管鱼类光感受器（photoreceptors）的特性使其理论上可探测远红外波段，但红外光仍常被用于行为记录与电生理实验（electrophysiological experiments）。作为本实验流程的示例，我们采用所提出的方案与装置，专门测试了840 nm红外光对斑马鱼昼夜节律钟（circadian clock）的影响，该节律钟调控着斑马鱼行为、生理与代谢的诸多方面。实验结果表明，红外光并不会对斑马鱼的昼夜节律钟产生影响。本研究结果可为未来开展水生生物光依赖过程相关研究提供坚实的研究框架。