Evolution of the response to fluctuating oxygen availability in facultative anaerobes

该项目将有助于更好地了解微生物如何对氧气供应的变化做出反应。有些生物体只能容忍氧气供应的微小波动。其他细菌和真菌，包括许多细菌和真菌，可以在有氧或没有氧的情况下生存，也可以在氧浓度介于两者之间的所有氧浓度下生存。这些生物体通过将它们产生能量的方式从依赖氧气的过程称为有氧呼吸转变为依赖氧气的过程，如发酵，从而实现了这种灵活性。这种灵活性允许这些生物在各种各样的不同环境中生活，但这是有代价的。这个项目的总体目标是更好地了解这一成本的分子和遗传基础。到目前为止，这只在非常少数的生物体中进行了研究，这在我们对为什么有些生物体比其他生物体更有能力适应自然环境中不断变化的氧气供应的理解上留下了很大的空白。该项目将通过比较更多细菌的分子反应来填补这一空白。该项目的结果将对理解氧气供应如何影响细菌与动植物宿主的相互作用具有重要意义。项目结果还将对生物技术应用产生影响，如生物燃料生产和其他依赖于工业环境中氧气可获得性操纵的工程生物过程。最后，该项目将在大学提供培训和教育机会，为K-12学生提供提高科学素养的外展活动，并为高中和中学教师提供专业发展机会。该项目将侧重于氧气供应波动对兼性厌氧细菌的进化影响。该项目建立在少数肠道细菌菌株的初步生长速度和转录组数据的基础上。目标1将使用大规模的表型分析来衡量在严格控制的氧气供应条件下，自然种群的立地变化对健康的影响。AIM 2将通过与基因组序列和转录本的关联研究，以及全基因组范围内平衡选择足迹的群体遗传学测试，将遗传和表型变异联系起来。相关基因座的子集将使用基因组工程进行验证。目标3将测试在实验进化的种群中氧气可获得性的定期波动是否会导致条件有利和/或有害的变化的持续。这一项目的结果有望显著提高人们对自然变化对氧气供应响应的重要性以及不同环境中健康权衡的分子基础的理解。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。

This project will lead to a better understanding of how microbes respond to changes in oxygen availability. Some organisms can only tolerate very small fluctuations in oxygen availability. Others, including many bacteria and fungi are able to live with or without oxygen, and at all oxygen concentrations in between. These organisms accomplish this flexibility by shifting how they generate energy from an oxygen-dependent process called aerobic respiration to oxygen-independent processes like fermentation. This flexibility allows these organisms to live in a wide variety of different environments, but it comes at a cost. The overall goal of this project is to better understand the molecular and genetic basis of that cost. To date, this has been investigated in a very small number of organisms, leaving a major gap in our understanding of why some organisms are better equipped than others to adjust to fluctuating oxygen availability in natural environments. This project will fill that gap by comparing the molecular response of a much larger number of bacteria. Results from this project will have implications for understanding how oxygen availability impacts interaction of bacteria with plant and animal hosts. Project results will also have implications for biotechnology applications, like biofuel generation and other engineered bioprocesses which depend on manipulation of oxygen availability in industrial settings. Finally, this project will provide training and educational opportunities at the university, outreach activities to increase science literacy for K-12 students, and professional development opportunities for high school and middle school teachers.This project will focus on the evolutionary impact of fluctuating oxygen availability on facultative-anaerobic bacteria. The project builds on preliminary growth rate and transcriptome data from a small number of strains of enterobacteria. Aim 1 will measure fitness impacts of standing variation in natural populations under rigorously controlled oxygen availability conditions using large-scale phenotyping. Aim 2 will link genetic and phenotypic variation using association studies with both genome sequences and transcriptomes, and population genetic tests for genome-wide footprints of balancing selection. A subset of implicated loci will be validated using genome engineering. Aim 3 will test whether regular fluctuations in oxygen availability in experimentally evolved populations leads to persistence of conditionally advantageous and/or antagonistically deleterious variation. Results from this project are expected to significantly advance understanding of the significance of natural variation in the response to oxygen availability and the molecular underpinnings of fitness tradeoffs in heterogeneous environments.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.