College of Science, Florida Institute of Technology, 150 West University Blvd, Melbourne, FL 32901, USA.
Int J Mol Sci. 2017 Sep 28;18(10):2068. doi: 10.3390/ijms18102068.
Many ecologically and economically important marine fish species worldwide spend portions of their lives in coastal regions that are increasingly inundated by artificial light at night. However, while extensive research illustrates the harmful effects of inappropriate light exposure on biological timing in humans, rodents and birds, comparable studies on marine fish are virtually nonexistent. This study aimed to assess the effects of light on biological clock function in the marine fish retina using the Atlantic tarpon () as a model. Using anti-opsin immunofluorescence, we observed robust rhythms of photoreceptor outer segment position (retinomotor movement) over the course of the daily light-dark cycle: cone outer segments were contracted toward the inner retina and rods were elongated during the day; the opposite occurred at night. Phase shifting the daily light-dark cycle caused a corresponding shift of retinomotor movement timing, and cone retinomotor movement persisted in constant darkness, indicating control by a circadian clock. Constant light abolished retinomotor movements of both photoreceptor types. Thus, abnormally-timed light exposure may disrupt normal clock function and harm vision, which in turn may affect prey capture and predator avoidance. These results should help inform efforts to mitigate the effects of coastal light pollution on organisms in marine ecosystems.
许多在全球范围内具有生态和经济重要性的海洋鱼类，其部分生命都在沿海地区度过，这些地区夜间受到越来越多的人工光的淹没。然而，尽管广泛的研究表明不适当的光照暴露对人类、啮齿动物和鸟类的生物钟生物节律有有害影响，但类似的海洋鱼类研究实际上是不存在的。本研究旨在使用大西洋鲷（）作为模型，评估光对海洋鱼类视网膜生物钟功能的影响。使用抗视蛋白免疫荧光，我们观察到在每日光-暗循环过程中，光感受器外段位置（视网膜运动）存在强大的节律：在白天，圆锥体外段向视网膜内收缩，杆状细胞伸长；晚上则相反。改变每日光-暗循环的相位会导致视网膜运动时间相应的移位，并且圆锥体视网膜运动在持续黑暗中持续存在，表明受生物钟控制。持续光照会使两种光感受器类型的视网膜运动都消失。因此，异常定时的光照可能会破坏正常的生物钟功能并损害视力，这反过来又可能影响猎物的捕获和捕食者的躲避。这些结果应该有助于为减轻沿海光污染对海洋生态系统中生物的影响提供信息。
