NSF RUI: Characterizing Adaptation to Heterogenous and Stressful Environments

这个项目利用了实验进化的优势，在实验进化中，生物在实验室中在规定的条件下进化。实验进化在微生物方面尤其成功，因为它们可以快速生长到庞大的种群规模，这使得进化的步伐足够快，可以在短时间内进行研究。在这种情况下，细菌在确定但可变的环境条件下繁殖，以模拟细菌在自然界中遇到的压力源。本项目旨在通过关注通过调节其他基因影响细胞行为的基因的作用来表征基因表达在适应和进化中的作用。在不断变化的环境中，调节基因的突变可能对细菌特别有利。这项工作将与西班牙裔和少数民族服务机构的本科生合作进行，该机构近90%的学生来自STEM中代表性不足的群体。此外，PI将把这个项目整合到高年级的微生物学课程中，作为每年48名本科生的真实研究经验，并与K-12教育工作者一起开展与这个项目相关的外展活动。通过这些方式，这项研究将有助于增加进入STEM管道的学生的多样性，并使他们更好地为STEM领域的角色做好准备。基因调控的变化是进化的驱动力。当比较不同物种时，顺式调控元件通常是进化变化的原因，而反式调控元件通常在生物体需要适应不断变化的环境时发生改变。微生物的实验进化研究已经开始探索这些因素的作用，但通常是在不变的环境中，功能或顺式调节变化都是有利的。该项目将探索反式调控因子在适应异质环境中的作用，首先确定影响大肠杆菌在复杂培养基中长期培养中存活的每个反式调控因子。然后，PI将描述这些反式调节因子在适应中的作用，首先将基因型与群体的转录组相关联，以确定基因表达变化，并确定哪些变化赋予生长表型。然后，PI将对突变细胞进行实验进化，以确定这些突变如何改变细胞适应异质环境的进化途径。了解这些类型的调节变化如何影响适应将有助于对进化原理的基本理解。这项研究由生物科学理事会分子和细胞生物科学部的遗传机制项目资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project takes advantage of experimental evolution in which organisms are evolved in the laboratory under defined conditions. Experimental evolution has been especially successful with microorganisms because they can grow quickly to large population sizes, making the pace of evolution fast enough to study in short periods of time. In this case, the bacteria are propagated under defined but variable environmental conditions to mimic the stressors bacteria encounter in nature. This project aims to characterize the role of gene expression in adaptation and evolution by focusing on the role of genes that can affect cellular behavior by regulating other genes. Mutations in regulatory genes may be particularly advantageous for bacteria in changing environments. This work will be performed in collaboration with undergraduate students at a Hispanic and Minority Serving Institution where almost 90% of students are from groups underrepresented in STEM. Further, the PI will integrate this project into an upper-division microbiology course as an authentic research experience for 48 undergraduate students per year, and perform outreach activities related to this project with K-12 educators. In these ways, the research will help to increase the diversity of students entering the STEM pipeline and leave them better prepared for roles in STEM fields.Changes in gene regulation are a driving force for evolution. Cis regulatory elements are often the cause of evolutionary change when comparing different species, whereas trans regulatory elements are often altered when organisms need to adapt to changing environments. Experimental evolution studies with microbes have begun to probe the role of these factors, but often in unchanging environments where either functional or cis regulatory changes would be favored. The PI will explore the role trans regulatory elements play in adaptation to a heterogeneous environment by first identifying each trans regulatory factor that affects survival of Escherichia coli in long-term cultures in complex media. Then, the PI will characterize the role of these trans regulatory factors in adaptation, by first correlating the genotype with the transcriptome of the population to identify gene expression changes, and determine which of those changes confer the growth phenotype. The PI will then perform experimental evolution on mutant cells to determine how these mutations may change the evolutionary pathways cells can use to adapt to a heterogeneous environment. Understanding how these types of regulatory changes affect adaptation will contribute to the fundamental understanding of evolutionary principles.This research is funded by the Genetic Mechanisms program in the Division of Molecular and Cellular Biosciences in the Directorate of Biological Sciences.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.