Collaborative Research: Do Diverse Members of the Epsilonproteobacteria Employ a Novel Nitrate Reduction Pathway?

智力优势：氮是所有生物生长所需的关键营养素。氮在地球上主要以气态形式存在，绝大多数生物无法吸收。因此，固定氮，无论是铵，亚硝酸盐或硝酸盐，是激烈的竞争。地球表面氮的大多数转化都是由微生物催化的，包括不同固定氮物种之间的相互转化。生长的首选氮物质是铵，通常是生态系统中的限制性营养素。该项目将详细介绍某些微生物“呼吸”或呼吸硝酸盐并产生铵的新方法。 它们这样做的原因和人类呼吸氧气的原因一样，都是为了保存能量。 硝酸盐呼吸本身并不新鲜，但本研究的主要模式细菌-深海鹦鹉螺-使用的机制是新颖的，可能对它在深海热液喷口谋生很重要。 亲戚N。此外，亦会研究携带编码相同途径的基因的深层真菌，这些真菌通常与动物有关，例如在人类的口腔和鸡的肠道内。 这种途径对这些生物体的益处目前尚不清楚。 通过了解这些细菌的氮代谢，我们将更多地了解氮如何在环境中移动，以及动物相关细菌如何在远离宿主的环境中生存。 该项目旨在利用基因组科学的最新技术进展，即高通量转录组学，并将其与更传统的生理学方法结合联合收割机来表征这种新的硝酸盐还原途径。 该项目将最终确定该途径的关键酶和中间体以及如何调节。更广泛的影响：PI将培训几名本科生和两名研究生在基因组使能微生物生理学，通过跨机构和跨学科的研究加强学习。 除了传统的微生物生理学和基本的氮化学，所有学生都将接触到最先进的高通量基因组学方法。 他们将通过讲习班接受负责任地进行研究的正式培训，并通过在国家会议上的发言和出版物以口头和书面形式介绍他们的研究，加强他们的专业发展。这些活动将纳入由国家科学基金资助的硝化网络区域网络的战略计划。 最后，这些结果将通过教师培训讲习班向K-12学生传播，并通过特拉华州大学海岸日等活动向公众传播，平均年出席人数超过8,000人，其他人则有机会由PI进行不太正式的演讲。

Intellectual Merit:Nitrogen is a key nutrient that all living beings need to grow. Nitrogen exists on planet Earth predominantly in gaseous form, inaccessible for assimilation to the vast majority of organisms. Hence fixed nitrogen, either as ammonium, nitrite or nitrate, is competed for vigorously. Most transformations of nitrogen in the Earth's surface are catalyzed by microbes including the interconversion between different fixed nitrogen species. The preferred nitrogen species for growth is ammonium, often a limiting nutrient in ecosystems. This project will detail a new means by which certain microbes "breathe" or respire nitrate and produce ammonium. They do this for the same reason humans breathe oxygen, to conserve energy. Nitrate respiration is not new per se, but the mechanism used by the primary model bacterium for this study, Nautilia profundicola, is novel and may be important for it to making a living at deep-sea hydrothermal vents. Relatives of N. profundicola will also be studied that carry the genes encoding the same pathway and are most often found in association with animals, for example in the oral cavity of humans and in the guts of chickens. The benefit of this pathway to these organisms is currently unclear. By understanding the nitrogen metabolism of these bacteria, we will learn more about how nitrogen moves in the environment and perhaps also how animal-associated bacteria survive in the environment away from their hosts. This project is designed to take advantage of the most recent technological advances in genome sciences, namely high-throughput transcriptomics, and combine it with more traditional physiological approaches to characterize this novel nitrate reduction pathway. This project will ultimately define the key enzymes and intermediates of this pathway and how it is regulated. Broader Impacts:The PIs will train several undergraduate students and two graduate students in genome-enabled microbial physiology, enhancing learning through cross-institutional and cross-disciplinary research. All students will be exposed to state of the art high-throughput genomics approaches in addition to traditional microbial physiology and basic nitrogen chemistry. They will be formally trained in the responsible conduct of research through workshops and their professional development will be enhanced by presenting their research in both oral and written form via presentations at national meetings and publications. These activities will be integrated into the strategic plan of the NSF-funded Nitrification Network RCN. Finally, these results will be disseminated to K-12 students via teacher-training workshops and to the public via events like the University of Delaware's Coast Day, with an average annual attendance of over 8,000, and others as opportunities arise for less formal presentations by the PIs.