RUI: A Mosaic Model of Host-Microbe Thermal Relationships

外温脊椎动物，如鱼、两栖动物和爬行动物，既表现出对环境温度的适应能力，又表现出适应温度条件变化的能力。同样，它们的病原体和寄生虫也是适应的，并有能力适应不断变化的环境温度。爬行动物是与鸟类和哺乳动物关系最密切的体温外动物，但它们的免疫系统在差异很大的体温下的确切反应尚不清楚，这对保护以及对感染的生理反应(如发烧和体温过低)的一般理解都有影响。这个项目将量化温度如何影响免疫系统最基本的功能之一，吞噬作用，或白细胞吞噬有害物质和病原体。沙漠龟将被用作研究生物，因为先前的研究表明，包括淋巴细胞在内的各种白细胞的吞噬作用对于限制呼吸道病原体非常重要。因此，大范围温度对白细胞活性、细菌生长及其相互作用的影响将被量化。吞噬淋巴细胞存在于所有类别的外温脊椎动物中，但它们在限制疾病方面的作用尚未在不同的体温下量化--尽管它们可能对保护、药物和食物生产具有重要意义。该项目吸引了一所为拉美裔服务的学院的大量本科生和硕士学生，该学院支持传统上在STEM领域代表性不足并经历经济困难的学生群体。本项目的重点是量化龟的吞噬细胞(异嗜性细胞、单核/巨噬细胞、B1淋巴细胞)、微生物(总细菌和龟特有细菌巴氏杆菌)以及它们之间的相互作用(杀菌活性)的季节性热性能曲线。这些检测将在体外进行量化，我们还会将它们与体内反应进行比较，体内反应进一步会受到生物体内生理变化的影响，例如应激反应。由于B1淋巴细胞的吞噬过程在外温脊椎动物中还不是很清楚，因此吞噬白细胞亚群的机制(吞噬、酸化、杀菌)将被量化。据预测，事实上，乌龟是白细胞的“马赛克”，具有不同的热性能，在不同的体温范围内保护动物。将外温动物视为不仅是温暖的或冷适应的，而且是由具有不同热偏好的细胞组成的，这代表了生态免疫学的范式转变，有助于更好地理解动物对不断变化的环境条件的反应。这项研究对保护生物多样性、管理不断变化的寄主-病原体系统以及维持动物种群健康的治疗等广泛的主题产生了广泛的影响。为硕士和本科生提供的有偿机会将增加STEM中少数族裔的代表性，并将加强我们系在我们课程中增加体验式学习的目标。与当地自然和发现中心的合作将使研究型学生成为科罗拉多州普韦布洛公立学校1,500多名小学生的榜样和导师。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Ectothermic vertebrate animals, such as fish, amphibians, and reptiles, show both adaptation to temperature in their environments and the ability to acclimate to changes in those thermal conditions. Similarly, their pathogens and parasites are also adapted, and have the ability to acclimate to changing environmental temperatures. Reptiles are the ectothermic animals most closely related to birds and mammals, but exactly how their immune systems react across widely varying body temperatures is not precisely known and has impacts for conservation as well as a general understanding of physiological reactions to infection, such as fevers and hypothermia. This project will quantify how temperature effects one of the most basic functions of the immune system, phagocytosis, or the engulfment of harmful agents and pathogens by white blood cells. The desert tortoise will be used as a study organism, because prior research showed that phagocytosis by a wide variety of white blood cells - including lymphocytes - is important in limiting respiratory pathogens. Therefore, the influence of a wide range of temperatures on white blood cell activity, bacterial growth, and their interactions will be quantified. Phagocytic lymphocytes exist across all classes of ectothermic vertebrates, but their role in limiting disease has not been quantified across varying body temperatures - despite the likely importance to conservation, medicine, and food production. This project engages a large number of undergraduate and Masters students at a Hispanic-Serving Institute which supports a student body that is traditionally under-represented in STEM fields and experiences financial hardship. This project focuses on quantifying seasonal thermal performance curves of phagocytic cells (heterophils, monocytes/macrophages, B1 lymphocytes) in tortoises, microbes (total and the tortoise-specific bacteria Pasteurella testudinis), and their interaction (bacteria-killing activity). These assays will be quantified in vitro, and we will also compare them to in vivo responses, which further can be influenced by physiological changes in the organism, such as stress responses. Because phagocytosis by B1 lymphocytes is a process that is not well understood in ectothermic vertebrates, mechanisms (engulfment, acidification, bacteria-killing) across sub-populations of phagocytic leukocytes will be quantified. The prediction is that tortoises are in fact a “mosaic” of leukocytes, with different thermal performance abilities, to protect the animals across a wide range of body temperatures. Viewing ectothermic animals as not just warm or cold-adapted, but composed of cells with different thermal preferences, represents a paradigm shift in ecological immunology and will help form a greater understanding of animals’ responses to changing environmental conditions. This research has wide-ranging impacts on topics as broad as the conservation of biodiversity, management of changing host-pathogen systems, and therapies to maintain health in animal populations. The paid opportunities offered to both Masters and undergraduate students will increase representation of minorities in STEM and will strengthen our departments’ goal to increase experiential learning in our curriculum. Collaboration with the local Nature and Discovery Center will allow research students to act as role models and mentors to more than 1,500 grade school students enrolled in public schools in Pueblo, Colorado.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.