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: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=663324
• 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，环境中氧气的减少（称为缺氧）是罕见的，但一旦发生，就会造成毁灭性的代谢后果，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。鉴于此，在所有脊椎动物中，鱼类拥有最多的耐缺氧物种也许并不奇怪。缺氧显然在塑造特征的进化中发挥了重要作用，这些特征可以提高它们在缺氧暴露下的存活率。尽管经过了几十年的研究，我们仍然没有完全理解为什么鱼类之间的缺氧耐受性存在差异的因素，以及为什么一些鱼类比其他鱼类更耐缺氧的生化机制。为了解决这一知识差距，我的研究项目利用了一组密切相关的鱼类中缺氧耐受性的自然变化，这些鱼类被称为雕刻鱼，它们栖息在海洋近岸环境中，从潮汐池到深水。有些物种只生活在潮汐池中，这种环境受每日潮汐循环的严重影响，导致氧气、温度、盐度、pH值等每天都有很大的波动，而其他物种则局限于潮下环境和较深的水域，这些参数不会发生波动。我的研究项目将这些雕塑与普通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中，确定缺氧耐受性的变化是由于基于遗传的自然选择和适应，还是由于生物体一生中以前的缺氧暴露。此外，我们还研究了解释这些雕刻蛋白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，因为由于与人类有关的活动，水生缺氧的发生率正在上升，因此鱼类和其他水生生物现在正经历着前所未有的环境波动，这些波动正在考验它们的容忍极限。了解设定物种对缺氧耐受极限的因素是预测哪些动物因环境变化而面临最大风险的重要第一步。这笔拨款将允许我每年培训5名研究生（3名博士和2名硕士）和2名本科生（1名理学士荣誉和1名NSERC-USRA），用最先进的分析和概念方法来理解动物如何与环境相互作用。**