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

[53028] Wood, Kevin B.细菌和真菌等微生物已经发展出了一系列在有毒环境中生存的分子工具，并且它们以惊人的速度进化出对新的压力源的抗性。抗生素耐药微生物的增加对公共卫生构成了紧迫的威胁，而对消毒剂和其他杀菌剂耐药的细菌在从废水处理到生物技术等许多领域提出了工程挑战。在过去的几十年里，细菌耐药性已经获得了重大的科学兴趣，导致对单个细胞中潜在耐药性的分子事件有了相对成熟的理解。然而，对于这些分子事件如何促进细菌群落的大规模行为，人们知之甚少，细菌群落通常由数十亿个同居细胞的异质混合物组成。细胞集合的行为仅仅是其分子和细胞部分的总和，还是由这些部分组合在一起产生的新现象所主导？这个项目试图通过结合细菌种群的定量实验和细菌群落的数学和计算模型来回答这个问题。目标是了解细胞群落在可能随时间变化的现实环境中对有毒刺激物（从防腐剂到消毒剂和刺激性化学物质）的反应方式。这项工作将为微生物群体的社区水平行为提供基本见解，并补充目前对耐药性及其进化的分子水平理解。在实践层面上，它将有助于控制和优化微生物生长的新工程策略，同时增强中学生在代表性不足的农村社区参与科学和工程实践（SEP）。该职业建议包括集中于细菌种群耐药性进化的综合研究和教育计划。该研究的目标是将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胁迫产生抗性的系统级机制。这项工作将利用定制的、计算机自动化的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，研究从杀菌剂到渗透胁迫等各种有害刺激的抗性进化。更具体地说，该项目将探讨人口密度和附带敏感性的作用，其中包括优化一种环境的抗性，在调节抗性进化速度方面所固有的权衡。这项工作将提供一个定量的、系统水平的观点，以补充目前对耐药性及其演变的分子水平的理解。它还将为控制和优化微生物生长的新工程策略奠定基础，并应用于生物技术和公共卫生，包括对抗抗生素耐药性。教育部分包括多方面的方法，以提高中学生参与科学和工程实践（SEP）在肯塔基州的农村地区。教育推广与拟议的细菌耐药性研究直接相关，包括与肯塔基大学的一位领先教育专家合作，并通过肯塔基山谷教育合作社（KVEC）与当地教育工作者合作，该合作社是一个为肯塔基东部农村地区学校服务的教育团体的集合。该项目每年对参与的高中进行实地考察，定期与教师、学生和执业科学家举行远程学习会议，并采用受拟议的抗微生物药物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系统级分析的SEP，提高学生在传统学科界面的职业意识，并提高复杂系统的数学和计算建模的具体技能和直觉。该奖项由CBET生物技术与生化工程项目颁发，由分子与细胞生物科学部的系统与合成生物学项目和综合有机系统部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.