CAREER: Investigating the Roles of Spatial Heterogeneity and Collateral Sensitivity in Evolved Bacterial Resistance to Environmental Stressors

1553028伍德，凯文B.细菌和真菌等微生物已经开发出一系列在有毒环境中生存的分子工具，它们以惊人的速度进化出对新应激源的抵抗力。具有抗生素耐药性的微生物的崛起对公众健康构成了紧迫的威胁，而对消毒剂和其他杀生剂具有耐药性的细菌在从废水处理到生物技术的许多场所都带来了工程挑战。在过去的几十年里，细菌耐药性引起了人们极大的科学兴趣，导致对单个细胞中潜在的耐药性的分子事件有了相对成熟的理解。然而，人们对这些分子事件如何影响细菌群落的大规模行为知之甚少，细菌群落通常由数十亿共生细胞的异质混合物组成。一组细胞的行为仅仅是它的分子和细胞部分的总和，还是被这些部分组装在一起的新现象所主导？这个项目试图通过将细菌种群的定量实验与细菌群落的数学和计算模型相结合来回答这个问题。其目标是了解在现实环境中，细胞群落对从防腐剂到消毒剂和刺激性化学物质的有毒刺激的反应方式，这些刺激可能会随着时间的推移而发生变化。这项工作将对微生物种群的社区行为提供基本的见解，并补充目前对耐药性及其进化的分子水平的理解。在实践层面上，它将有助于新的工程战略，以控制和优化微生物生长，同时加强中学生对科学和工程实践(SEP)的参与，在代表性不足的农村社区。这项职业提案包括专注于细菌种群耐药性演变的综合研究和教育计划。这项研究的目标是将对微生物种群的定量实验与细菌进化的随机模型相结合，以了解细胞群落对环境压力产生抵抗力的系统级机制。这项工作将利用定制的计算机自动化微生物培养设备和高通量DNA测序，在以空间异质性和时间波动为特征的现实环境中，研究从杀生剂到渗透胁迫等各种有害刺激的抗性进化。更具体地说，该项目将探索人口密度和附带敏感性在调节耐药性进化速度方面的作用，其中包括在优化一种环境的抗性时固有的权衡。这项工作将提供一个定量的、系统水平的视角，以补充目前分子水平对耐药性及其进化的理解。它还将为控制和优化微生物生长的新工程战略奠定基础，应用生物技术和公共卫生，包括抗击抗生素耐药性。教育内容包括在肯塔基州农村地区加强中学生参与科学和工程实践(SEP)的多方面方法。教育外展与拟议的细菌耐药性研究直接相关，涉及与肯塔基大学一位领先的教育专家的合作，以及通过肯塔基山谷教育合作社(KVEC)与当地教育工作者的伙伴关系，KVEC是一个为肯塔基州东部农村地区的学校提供服务的教育团体的集合。该项目结合了对参与的高中的年度实地访问，与教师、学生和执业科学家的定期远程学习会议，以及受拟议的抗菌素耐药性研究启发的电子和在线工具。该提案的目标是让学生参与生物系统的系统级分析，提高学生对传统学科交界处的职业生涯的认识，并提高复杂系统的数学和计算建模的具体技能和直觉。这个职业奖项由CBET部门的生物技术和生物化学工程项目共同资助，由分子和细胞生物科学部门的系统和合成生物学项目以及综合组织系统部门的综合生态生理学项目共同资助。

1553028 Wood, Kevin B. Microbes such as bacteria and fungi have developed a wide range of molecular tools for surviving in toxic environments, and they evolve resistance to new stressors with remarkable speed. The rise of antibiotic-resistant microbes poses an urgent threat to public health, while bacteria resistant to disinfectants and other biocides present engineering challenges in numerous venues, ranging from wastewater treatment to biotechnology. Bacterial resistance has garnered significant scientific interest over the past several decades, leading to a relatively mature understanding of the molecular events underlying resistance in individual cells. However, relatively little is known about how these molecular events contribute to the large-scale behavior of bacteria communities, which are often comprised of heterogeneous mixtures of billions of cohabitating cells. Is the behavior of a collection of cells simply a sum of its molecular and cellular parts, or is it instead dominated by new phenomena that arise from the way those parts fit together? This project attempts to answer this question by combining quantitative experiments on bacterial populations with mathematical and computational models of bacterial communities. The goal is to understand the way cellular communities respond to toxic stimuli ranging from antiseptics to disinfectants and harsh chemicals in realistic environments that may change over time. The work will offer fundamental insights into the community-level behavior of microbial populations and complement the current molecular-level understanding of resistance and its evolution. On a practical level, it will contribute to new engineering strategies for controlling and optimizing microbial growth while enhancing secondary student engagement with science and engineering practices (SEP) in underrepresented rural communities.This CAREER proposal includes integrated research and education plans focused on the evolution of resistance in bacterial populations. The goal of the research is to combine quantitative experiments on microbial populations with stochastic models of bacterial evolution to understand systems-level mechanisms by which cellular communities develop resistance to environmental stresses. The work will leverage customized, computer-automated microbial culture devices and high-throughput DNA sequencing to investigate the evolution of resistance to a wide range of deleterious stimuli, ranging from biocides to osmotic stress, in realistic environments characterized by spatial heterogeneity and temporal fluctuations. More specifically, the project will explore the roles of population density and collateral sensitivity, which encompasses the trade-offs inherent in optimizing resistance for one environment, in modulating the rate of resistance evolution. The work will offer a quantitative, systems-level perspective to complement the current molecular-level understanding of resistance and its evolution. It will also lay the groundwork for new engineering strategies for controlling and optimizing microbial growth, with applications for biotechnology and public health, including the fight against antibiotic resistance.The educational component includes a multi-faceted approach to enhance secondary student engagement with science and engineering practices (SEP) in rural regions of Kentucky. The educational outreach is directly related to the proposed research on bacterial resistance and involves collaboration with a leading education expert at the University of Kentucky and partnerships with local educators through the Kentucky Valley Educational Cooperative (KVEC), a collection of educational groups serving schools in rural regions of eastern Kentucky. The project uses a combination of annual site visits to participating high schools, regular distance learning meetings with teachers, students and practicing scientists, and electronic and online tools inspired by the proposed research on antimicrobial resistance. The goal of the proposal is to engage students in SEP for systems-level analysis of biological systems, increase student awareness of careers at the interface of traditional disciplines, and improve specific skills and intuition for mathematical and computational modeling of complex systems.This CAREER award by the Biotechnology and Biochemical Engineering Program of the CBET Division is co-funded by the Systems and Synthetic Biology Program of the Division of Molecular and Cellular Biosciences and by the Integrative Ecological Physiology Program of the Division of Integrative Organismal Systems.