ANT LIA: Hypoxia Tolerance in Notothenioid Fishes

第1部分：非技术描述：全球气候变暖增加了全球海洋和淡水环境中低氧事件的频率和严重程度，这些事件威胁到水生生态系统的健康和鱼类种群的生存能力。围绕南极洲的南大洋在历史上一直是一个稳定的、冰冷的、富氧的环境，但现在正以前所未有的速度变暖，比南半球所有其他地区都要快。南极鱼类在零度以下的温度下进化，这种温度在很长一段时间内都很稳定，它们的特征使它们能够在寒冷的水域中茁壮成长，但对变暖的适应能力却减弱了。目前，人们对南极鱼类耐受缺氧或低氧环境的能力知之甚少，这种环境通常伴随着气候变暖。本研究将研究四种南极鱼类的缺氧耐受性，其中包括两种冰鱼，它们缺乏携带氧气的蛋白质血红蛋白，这可能会损害它们在缺氧条件下为组织充氧的能力。四种南极鱼类的耐缺氧性将与生活在南美洲温暖沿海地区的一种相关鱼类进行比较。我们将评估和比较这五种鱼类对缺氧的生理和生化反应，以支持我们对南极鱼类应对不断变化的环境的能力的预测。本研究将为本科生和研究生提供培训机会，并提供博士后研究人员。由太平洋水族馆主办的为期一年的系列研讨会将邀请在南极洲工作的女科学家，以激励大洛杉矶地区的年轻人追求科学事业。第2部分:技术描述:被测试的总体假设在这个项目的长期进化南极notothenioid鱼类在寒冷,富氧环境减少了挂载一个健壮的生理能力,生物化学,和分子应对缺氧相关相比,寒温鱼类。比较了南极红鳍南极南极鱼、科氏南极鱼和罗西南极鱼的耐缺氧能力；南极无血红蛋白冰鱼、棘毛头鱼和棘毛鱼；以及基底的寒温带南极鱼，一种从未在极锋以南水域生活过的物种。维持维持代谢需求（O2crit）所需的最低氧气水平将被量化。然后将动物暴露在65%的o2临界环境中48小时，通过测量红细胞压积和血红蛋白水平，以及大脑、肝脏、糖酵解和心肌的代谢物来评估对缺氧的反应。有氧和无氧代谢关键酶的最大活性将被量化，以评估在缺氧条件下合成ATP的能力。鳃的重塑将用光学和扫描电子显微镜进行分析。肝脏和大脑对缺氧的分子反应将通过量化氧稳态的主要转录调节因子-缺氧诱导因子-1 （HIF-1）的水平来表征，而缺氧基因的表达将通过RNA-Seq来量化。细胞培养将用于确定先前在南极鱼HIF-1中发现的插入突变是否影响HIF-1驱动基因表达的能力，从而影响低氧耐受性。该项目的结果将提供迄今为止对南极鱼类耐缺氧能力最全面的评估。更广泛的影响包括为本科生和研究生以及博士后研究助理提供研究培训机会，重点是让阿拉斯加原住民学生参与研究。与太平洋水族馆合作，将举办为期一年的公众系列研讨会，展示9名在南极洲进行研究的女性的研究和职业生涯。该系列的目标是培养和授权大洛杉矶地区的中学生和高中生社区追求他们在科学和相关领域的兴趣，并提高研究科学家的公众参与能力，以便他们更好地激励STEM领域的青年和早期职业科学家。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Part 1: Non-technical description:Global climate warming is increasing the frequency and severity of low oxygen events in marine and freshwater environments worldwide, and these events threaten the health of aquatic ecosystems and the viability of fish populations. The Southern Ocean surrounding Antarctica has historically been a stable, icy-cold, and oxygen-rich environment, but is now warming at an unprecedented rate and faster than all other regions in the Southern hemisphere. Antarctic fishes have evolved in sub-zero temperatures that have been stable over long periods of time with traits allowing them to thrive in frigid waters, but with diminished resilience to warming temperatures. Presently little is known about the ability of Antarctic fishes to withstand hypoxic, or low-oxygen, conditions that often accompany warming. This research will investigate the hypoxia tolerance of four species of Antarctic fishes, including two species of icefishes that lack the oxygen-carrying protein, hemoglobin, which may compromise their ability to oxygenate tissues under hypoxic conditions. The hypoxia tolerance of four Antarctic fish species will be compared to that of a related fish species inhabiting warmer coastal regions of South America. Physiological and biochemical responses to hypoxia will be evaluated and compared amongst the five species to bolster our predictions of the capacity of Antarctic fishes to cope with a changing environment. This research will provide training opportunities for undergraduate and graduate students, and a postdoctoral research fellow. A year-long seminar series hosted by the Aquarium of the Pacific will feature female scientists who work in Antarctica to inspire youth in the greater Los Angeles area to pursue careers in science.Part 2: Technical description: The overarching hypothesis to be tested in this project is that the long evolution of Antarctic notothenioid fishes in a cold, oxygen-rich environment has reduced their capacity to mount a robust physiological, biochemical, and molecular response to hypoxia compared to related, cold-temperate fish species. Hypoxia tolerance will be compared among the red-blooded Antarctic notothenioids, Notothenia coriiceps and Notothenia rossii; the hemoglobinless Antarctic icefishes, Chaenocephalus aceratus and Chionodraco rastrospinosus; and the basal, cold-temperate notothenioid, Eleginops maclovinus, a species that has never inhabited waters south of the Polar Front. The minimum level of oxygen required to sustain maintenance metabolic requirements (O2crit) will be quantified. Animals will then be exposed to 65% of O2crit for 48 hours, and responses to hypoxia will be evaluated by measuring hematocrit and hemoglobin levels, as well as metabolites in brain, liver, glycolytic and cardiac muscles. Maximal activities of key enzymes of aerobic and anaerobic metabolism will be quantified to assess capacities for synthesizing ATP in hypoxic conditions. Gill remodeling will be analyzed using light and scanning electron microscopy. The molecular response to hypoxia will be characterized in liver and brains by quantifying levels of the master transcriptional regulator of oxygen homeostasis, hypoxia-inducible factor-1 (HIF-1), and hypoxic gene expression will be quantified using RNA-Seq. Cell cultures will be used to determine if a previously identified insertion mutation in notothenioid HIF-1 affects the ability of HIF-1 to drive gene expression and thus, hypoxia tolerance. The results of this project will provide the most comprehensive assessment of the hypoxia tolerance of Antarctic fishes to date. Broader impacts include research training opportunities for undergraduate and graduate students and a postdoctoral research associate, with a focus on involving Native Alaskan students in research. In partnership with the Aquarium of the Pacific, a year-long public seminar series will be held, showcasing the research and careers of 9 women who conduct research in Antarctica. The goal of the series is to cultivate and empower a community of middle and high school students in the greater Los Angeles area to pursue their interests in science and related fields, and to enhance the public engagement capacities of research scientists so that they may better inspire youth and early career scientists in STEM fields.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.