Department of Marine Biology and Ecology, University of Miami, Rosenstiel School of Marine and Atmospheric Science, Miami, FL, USA.
Department of Marine Biology and Ecology, University of Miami, Rosenstiel School of Marine and Atmospheric Science, Miami, FL, USA.
Sci Total Environ. 2019 Feb 15;651(Pt 2):3070-3078. doi: 10.1016/j.scitotenv.2018.10.093. Epub 2018 Oct 9.
Pelagic fish have long been presumed to produce buoyant embryos which float and hatch at or near surface waters. Due to their transparency and rapid development, mahi embryos are thought to be especially vulnerable to stressors occurring in surface waters, such as ultraviolet radiation (UVR) and increased temperatures. In the present study, we suggest a possibly critical mechanism of UVR avoidance by pelagic fish embryos. Specifically, we provide evidence that mahi embryos are able to sense UVR and may alter buoyancy as a means of reducing exposure to the most harmful stressors occurring in the upper layers of the water column. Further, once the UVR exposure was terminated, embryos displayed fast recovery of positive buoyancy indicating this response is rapidly dynamic and not pathological. The mechanism behind buoyancy control is not known, but evidence from the current study suggests that ammonia sequestration, as seen in multiple other fish species, is not the primary control mechanism employed by embryonic mahi. Finally, expression of antioxidant and UV repair enzymes were investigated to elucidate possible involvement in observed buoyancy changes and to explore alternative methods of repairing UVR damage.
远洋鱼类长期以来被认为会产生具有浮力的胚胎，这些胚胎会在水面或接近水面的地方漂浮和孵化。由于它们的透明性和快速发育，马林鱼胚胎被认为特别容易受到水面上的应激源的影响，如紫外线辐射 (UVR) 和温度升高。在本研究中，我们提出了远洋鱼类胚胎避免 UVR 的一种可能的关键机制。具体来说，我们提供了证据表明，马林鱼胚胎能够感知 UVR，并可能通过改变浮力来减少暴露在水柱上层最有害的应激源。此外，一旦 UVR 暴露停止，胚胎就会迅速恢复正浮力，这表明这种反应是快速动态的，而不是病理性的。浮力控制的机制尚不清楚，但本研究的证据表明，氨的隔离（在多种其他鱼类中可见）不是胚胎马林鱼所采用的主要控制机制。最后，研究了抗氧化剂和 UV 修复酶的表达，以阐明它们在观察到的浮力变化中的可能作用，并探索修复 UVR 损伤的替代方法。
