Structural variation of the nitrogen-fixing heterocyst: Addressing the role of gas permeability in evolutionary divergence

微生物固氮每年为自然和农业系统提供大量可利用的、维持生命的氮。 由于氧气会不可逆地毒害固氮机制，因此管理氧气暴露是固氮生物的核心问题，因为固氮生物使用氧气来制造能量。 蓝藻异形胞是一种专门的细胞，旨在提供足够的能量和环境有利于固氮。 在这里，研究人员建议使用异形胞作为模型来解决温度变化如何塑造生物结构的形式和功能，从而操纵与环境的气体交换。 具体来说，研究人员将结合联合收割机化学，生理和遗传方法来测试如何自然发生的变异与环境温度相关的异形胞结构影响的温度依赖性的异形胞功能，通过修改氧气流入异形胞。 该项目承诺对这种生态和经济上重要的结构如何受到温度升高的影响及其在面对环境变化时的进化反应能力提出新的和一般的见解。由于异形胞也是目前从光中产生氢能的最佳模型，因此该项目的结果将对如何设计可靠且负担得起的氢源产生影响。 该项目通过在不同层面的指导和推广，包括黄石公园的实地课程，揭示了微生物和野生动物在世界上第一个国家公园控制氮供应的相互依赖关系，整合了研究和教育。

Nitrogen (N) fixation by microorganisms contributes enormous quantities of usable, life-sustaining N to natural and agricultural systems each year. Because oxygen irreversibly poisons the N-fixation machinery, managing oxygen exposure is a central problem for N-fixing organisms, which use oxygen to make energy. The cyanobacterial heterocyst is a specialized cell designed to provide both sufficient energy and an environment favorable for N fixation. Here, the investigators propose to use the heterocyst as a model to address how changing temperature shapes the form and function of biological structures, which manipulate gas exchange with the environment. Specifically, the investigators will combine chemical, physiological, and genetic approaches to test how naturally-occurring variation in heterocyst architecture associated with environmental temperature impacts the temperature-dependence of heterocyst function through the modification of oxygen flow into the heterocyst. The project promises novel and general insights into how this ecologically and economically important structure is affected by increasing temperature and its capacity for an evolutionary response in the face of environmental change. Because the heterocyst is also currently the best model for producing hydrogen energy from light, the project outcomes will have implications for how to engineer a reliable and affordable source of hydrogen. The project integrates research and education through mentoring and outreach at diverse levels, including a field course in Yellowstone that reveals the interdependence of microorganisms and wildlife for controlling N availability in the world's first national park.