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

固氮异形体的结构变异：解决气体渗透性在进化分歧中的作用

• 批准号: 1147195
• 负责人: Scott Miller
• 金额: $ 48.07万
• 依托单位: University of Montana
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-03-01 至 2016-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1147195&HistoricalAwards=false
• 关键词: Structural; variation; nitrogen; fixing; heterocyst

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.

微生物固氮（N）每年为自然和农业系统贡献大量可用的、维持生命的氮。 由于氧气不可逆地毒害固氮机制，因此管理氧气暴露是固氮生物体（利用氧气产生能量）的核心问题。 蓝藻异形细胞是一种专门的细胞，旨在提供足够的能量和有利于固氮的环境。 在这里，研究人员建议使用异形体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，研究人员将结合化学、生理和遗传学方法来测试与环境温度相关的异形体结构中自然发生的变化如何通过改变进入异形体的氧气流量影响异形体功能的温度依赖性。 该项目对这种具有生态和经济重要性的结构如何受到温度升高的影响及其面对环境变化的进化反应能力提供了新颖而全面的见解。由于异质体也是目前利用光生产氢能的最佳模型，因此该项目的成果将对如何设计可靠且负担得起的氢源产生影响。 该项目通过不同层面的指导和推广将研究和教育融为一体，包括在黄石公园举办的实地课程，揭示了微生物和野生动物在控制世界上第一个国家公园的氮供应方面的相互依赖性。