Collaborative Research: Evolution of information processing in the Vibrio fischeri pheromone-signaling network

信息素信号传导控制许多重要的细菌行为，从细菌与其宿主之间的良性共生关系到细菌病原体对人体组织和器官的定殖。 该项目的目的是了解当地环境（例如，宿主中的环境）影响信息素信号传导和细菌行为如定殖。该项目将基于分子的微生物学方法与物理和数学工具相结合，以开发这一过程的更完整的实验和理论图片。该项目将通过培训研究生和本科生进行跨学科实验室研究来加强教育。这些研究经验将为学生在生物科学领域的广泛职业生涯做好准备。该项目还包括对中学理科教师进行正式培训，这些教师主要来自拥有大量来自服务不足人口的学生的高中。费氏弧菌信息素信号传导的最重要的元件是LuxI/LuxR信号合成酶/受体，其产生并检测30 C6高丝氨酸内酯（HSL）信息素，以及AinS/AinR合成酶/受体系统，其采用C8 HSL信息素来驱动不同的信号传导级联。这些系统的复杂性通过由LuxR对两个HSL信号的识别产生的串扰、通过响应于环境而调制Lux和Ain的事实以及通过在Lux和Ain级联中存在正反馈而增强。本项目的主要目标是了解系统如何从其环境中收集和集成信息。具体的目标是（i）了解关键调节器LuxR及其变体如何整合来自两个HSL信号的信息，（ii）识别更广泛的信息素信号通路的激活状态，并探索环境输入如何导致特定输出，和（iii）测试该信号系统的结构允许空间异质环境触发种群的假设-在较长的距离和时间尺度上的广泛响应。该项目将使用细胞计数和基因报告方法来表征LuxR相互作用和系统状态。它还将使用微流体和显微镜来探索异质环境中的信号动力学。这些结果有望为细菌如何利用环境线索控制种群水平的行为提供新的见解。

Pheromone signaling controls many important bacterial behaviors, ranging from benign symbiotic relationships between bacteria and their hosts to colonization of human tissues and organs by bacterial pathogens. The aim of this project is to understand how the local environment (e.g., the environment in the host) affects pheromone signaling and bacterial behaviors such as colonization. This project combines molecular-based microbiology methods with physical and mathematical tools to develop a more complete experimental and theoretical picture of this process. The project will enhance education by training graduate and undergraduate students to perform cross-disciplinary laboratory research. These research experiences will prepare the students for a wide range of careers in the biosciences. The project also includes a formal training experience for secondary science teachers, primarily from high schools with large numbers of students from under-served populations. The most important elements of Vibrio fischeri pheromone signaling are the LuxI/LuxR signal-synthase/receptor, which produces and detects a 3OC6 homoserine lactone (HSL) pheromone, and the AinS/AinR synthase/receptor system, which employs a C8 HSL pheromone to drive a different signaling cascade. The complexity of these systems is enhanced by the crosstalk generated by LuxR's recognition of both HSL signals, by the fact that both Lux and Ain are modulated in response to the environment, and by the presence of positive feedback in both the Lux and Ain cascades. The primary goal of this project is to understand how the system gathers and integrates information from its environment. The specific aims are to (i) understand how the pivotal regulator LuxR and its variants integrate information from the two HSL signals, (ii) identify the activation states of the broader pheromone-signaling circuitry and explore how environmental inputs lead to specific outputs, and (iii) test the hypothesis that the architecture of this signaling system allows spatially-heterogeneous environments to trigger population-wide responses over extended distance and time scales. The project will use cytometry and gene reporter methods to characterize LuxR interactions and system states. It will also use microfluidics and microscopy to explore signaling dynamics in heterogeneous environments. The results are expected to yield new insights into how bacteria use environmental cues to control population-level behaviors.