Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada N9B 3P4.
Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario, Canada N9B 3P4.
G3 (Bethesda). 2019 Mar 7;9(3):933-941. doi: 10.1534/g3.118.200920.
Olfaction mediates behaviors necessary for survival and reproduction in fishes. Anthropogenic inputs of contaminants into aquatic environments, specifically copper, are known to disrupt a broad range of olfactory-mediated behaviors and can cause long-lasting damage even at low concentrations that have profound impacts on the biology of aquatic organisms. The sea lamprey ( is a primitive fish species invasive to the North American Great Lakes that relies on olfaction to navigate during natal homing and in mate choice during reproduction. To investigate effects of copper on sea lamprey olfaction and the potential for maintenance of olfactory function during copper exposure, we exposed juvenile sea lamprey to environmentally ecologically relevant copper concentrations (0, 5, 10 and 30 µg/L) for 24 hr and characterized gene transcription response in olfactory tissue (, peripheral olfactory organ and olfactory bulb) and forebrain using whole transcriptome sequencing. Copper exposure induced a pattern of positive dose-dependent transcriptional response. Expression changes primarily reflected up-regulation of genes involved in apoptosis and wound healing. Unlike higher vertebrates, genes specifically related to the olfactory senses of the sea lamprey, , olfactory receptors, exhibited little transcriptional response to copper exposure, suggesting the mechanism of copper-induced olfactory impairment is through necrosis of the olfactory bulb and not copper-selective inhibition of olfactory receptors. Fully two-thirds of the differentially expressed genes at higher doses of copper have no known function and thus represent important candidates for further study of the responses to copper-induced olfactory injury. Our results shed light on the evolution of vertebrate olfactory repair mechanisms and have important implications for the conservation and management of both invasive and native populations of lamprey.
嗅觉在鱼类的生存和繁殖中起着至关重要的作用。人为将污染物输入到水生环境中，特别是铜，已知会破坏广泛的嗅觉介导的行为，并可能在低浓度下造成持久的损害，即使这些浓度很低，也会对水生生物的生物学产生深远的影响。海七鳃鳗（Petromyzon marinus）是一种入侵北美的原始鱼类物种，它依靠嗅觉在出生地归巢和繁殖期间选择配偶。为了研究铜对海七鳃鳗嗅觉的影响以及在铜暴露期间维持嗅觉功能的潜力，我们将幼年海七鳃鳗暴露于环境生态相关的铜浓度（0、5、10 和 30 µg/L）中 24 小时，并使用全转录组测序来描述嗅觉组织（外周嗅觉器官和嗅球）和前脑的基因转录反应。铜暴露诱导了一种正剂量依赖性的转录反应模式。表达变化主要反映了与细胞凋亡和伤口愈合相关的基因上调。与高等脊椎动物不同，海七鳃鳗特有的嗅觉相关基因，如嗅觉受体，对铜暴露的转录反应很小，这表明铜诱导嗅觉损伤的机制是通过嗅球的坏死，而不是铜对嗅觉受体的选择性抑制。在较高剂量的铜下，有三分之二的差异表达基因没有已知的功能，因此它们是进一步研究铜诱导嗅觉损伤反应的重要候选基因。我们的研究结果揭示了脊椎动物嗅觉修复机制的进化，并对七鳃鳗入侵和本地种群的保护和管理具有重要意义。
