Mechanisms and Evolution of Hypoxia Tolerance

耐缺氧的机制和进化

• 批准号: RGPIN-2015-05337
• 负责人: Richards, Jeffrey
• 金额: $ 4.15万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=690712
• 关键词: Mechanisms; Evolution; Hypoxia; Tolerance

For most air-breathing vertebrates, decreases in environmental oxygen (termed hypoxia) are a rare occurrence, but when they do occur they can have devastating metabolic consequences resulting in death within minutes. In the aquatic environment however, periods of hypoxia are a common, naturally occurring phenomenon. In light of this, it is perhaps not surprising that among all vertebrates, fish boast the largest number of hypoxia tolerant species. Hypoxia has clearly played an important role in shaping the evolution of traits that enhance their survival during hypoxia exposure. Despite several decades of study, we still do not have a complete understanding of the factors that explain why there is variation in hypoxia tolerance among fish and the biochemical mechanisms that explain why some fish are more tolerant of hypoxia than others. To address this knowledge gap, my research program uses the natural variation in hypoxia tolerance seen among a group of closely related fish species called sculpins, which inhabit the marine near shore environment, from tidepools to deep waters. Some species live only within tidepools, which are environments that are heavily influenced by the daily tidal cycle, resulting in large, daily fluctuations in oxygen, temperature, salinity, pH, etc, while other species are confined to subtidal environments and deeper waters that do not experience fluctuations in these parameters. My research program uses these sculpins along with a combination of common garden experiments and hypoxia exposures, in adults, parents, and developing embryos, to determine whether variation in hypoxia tolerance is due to genetically based natural selection and adaptation or due to previous hypoxia exposure during the organism's lifetime. In addition, we investigate the molecular, biochemical, and physiological mechanisms that explain variation in hypoxia tolerance in these sculpins. Research of this nature is important because the prevalence of aquatic hypoxia is on the rise due to human-related activities, thus fishes and other aquatic organisms are now experiencing unprecedented fluctuations in their environment that are testing their tolerance limits. Understanding the factors that set species' tolerance limits to hypoxia is an essential first step in predicting which animals will be most at risk due to a changing environment. This grant will allow me to train 5 graduate (3PhD & 2MSc) and 2 undergraduate (1 BSc Honors & 1 NSERC-USRA) students per year in the most advanced analytical and conceptual approaches for understanding how animals interact with their environment. **

对于大多数呼吸空气的脊椎动物来说，环境氧气的减少（称为缺氧）是罕见的，但当它们发生时，它们可能会产生破坏性的代谢后果，导致几分钟内死亡。 然而，在水生环境中，缺氧期是一种常见的自然现象。 有鉴于此，在所有脊椎动物中，鱼类拥有最多的耐缺氧物种可能并不奇怪。低氧显然在塑造增强低氧暴露期间存活的性状的进化方面发挥了重要作用。 尽管经过几十年的研究，我们仍然没有完全了解解释为什么鱼类耐缺氧性存在差异的因素，以及解释为什么某些鱼类比其他鱼类更耐缺氧的生化机制。为了解决这一知识缺口，我的研究计划使用了一组密切相关的鱼类物种之间的缺氧耐受性的自然变化，称为杜父鱼，居住在海洋附近的海岸环境，从潮池到深水沃茨。有些物种只生活在潮池中，这是一种受每日潮汐周期影响很大的环境，导致氧气、温度、盐度、pH值等每日大幅波动，而其他物种则局限于潮下环境和较深的沃茨，这些参数不会出现波动。 我的研究计划使用这些杜父鱼沿着与常见的花园实验和缺氧暴露相结合，在成人，父母，和发育中的胚胎，以确定是否缺氧耐受性的变化是由于遗传基础的自然选择和适应或由于以前的缺氧暴露在有机体的一生。此外，我们还研究了解释这些杜父鱼缺氧耐受性变化的分子、生化和生理机制。这种性质的研究很重要，因为由于人类相关活动，水生缺氧的流行率正在上升，因此鱼类和其他水生生物现在正在经历前所未有的环境波动，这正在考验它们的耐受极限。了解设定物种对缺氧耐受极限的因素是预测哪些动物将因环境变化而面临最大风险的重要第一步。这笔赠款将使我能够每年培训5名研究生（3 PhD和2 MSc）和2名本科生（1名荣誉理学士和1名NSERC-USRA）学生，了解动物如何与环境相互作用的最先进的分析和概念方法。 **