Stochastic phenotype switching controlled by c-di-GMP in Vibrio cholerae

微生物可以形成称为生物膜的群落，影响人类活动的许多方面。例如，微生物可用于处理废水和提高农业土壤生产力。了解微生物是如何在不同的环境中组织和生存的，对于促进有益的结果以及减轻有害影响很重要。这个项目将专注于微生物在不断变化的环境中生存的惊人能力--通过一种称为表型多样性的过程--使它们能够产生具有广泛行为或特征的后代。预测微生物的表型多样性行为是一个尚未解决的主要问题。该项目将使用环境细菌和人类病原体霍乱弧菌来研究细菌产生表型多样性的机制。从这个项目中学到的基本原则将与其他微生物直接相关，从而促进微生物的管理和工程以获得有益的结果。此外，该项目将为本科生和研究生提供研究培训，包括来自代表性不足群体的个人。通过与中级科学教育工作者和位于密歇根州兰辛的科学博物馆Impression 5的合作，将与广大观众分享新知识。该项目将调查第二信使双-(3-5)-环二聚鸟苷一磷酸(c-di-GMP)在控制霍乱弧菌克隆种群表型多样性方面的作用。C-di-GMP通过一个复杂的信号网络整合环境信号，以控制移动和生物膜生活方式之间的转换等因素。假设c-di-GMP信号改变转录调控对分子过程固有的随机波动的敏感性，以控制不同表型的比例。这个项目将使用数学建模、定量显微镜和行为跟踪相结合的方法来量化不同实验条件下表型多样性的调节。细胞跟踪和荧光显微镜将被用来直接在单个细胞中将信号活动与行为联系起来。正在生长的细胞中运动表型和生物膜形成表型之间的转换率将通过时间推移实验进行量化。最后，将使用遗传学方法来操纵c-di-GMP水平和转录调控，以检验理论模型中的特定预测。总体而言，该项目将阐明允许信号网络将随机波动与环境信号相结合以产生和控制克隆种群中有利的表型多样性的设计原则。

Microbes can form communities called biofilms that affect many aspects of human activities. For example, microbes can be used to treat wastewater and improve agricultural soil productivity. Understanding how microbes organize and persist in different environments is important for promoting beneficial outcomes, as well as mitigating harmful effects. This project will focus on an amazing ability microbes have for surviving in changing environments--through a process called phenotypic diversity--which enables them to produce progeny with a wide range of behaviors or characteristics. Predicting phenotypic diversity behaviors in microbes is a major unsolved problem. This project will use the environmental bacterium and human pathogen, Vibrio cholerae, to investigate the mechanisms used by bacteria to generate phenotypic diversity. The fundamental principles learned from this project will be directly relevant to other microorganisms, thus, facilitating the management and engineering of microbes for beneficial outcomes. In addition, this project will provide research training for undergraduate and graduate students, including individuals from underrepresented groups. New knowledge will be shared with a broad audience through collaborations with secondary science educators and Impression 5, a science museum in Lansing, MI.This project will investigate the role of the second messenger bis-(3-5)-cyclic dimeric guanosine monophosphate (c-di-GMP) in controlling phenotypic diversity in clonal populations of Vibrio cholerae. c-di-GMP integrates environmental signals through a sophisticated signaling network to control, among other factors, the transition between motile and biofilm lifestyles. The hypothesis is that c-di-GMP signaling changes the sensitivity of transcriptional regulation to stochastic fluctuations inherent to molecular processes to control the proportions of different phenotypes. This project will use a combination of mathematical modeling, quantitative microscopy, and behavioral tracking to quantify the regulation of phenotypic diversity under different experimental conditions. Cell tracking and epifluorescence microscopy will be used to correlate signaling activity with behavior directly in single cells. The transition rates between motile and biofilm-forming phenotypes in growing cells will be quantified using time-lapse experiments. Finally, a genetic approach will be used to manipulate c-di-GMP levels and transcription regulation to test specific predictions from theoretical models. Overall, this project will elucidate design principles that allow signaling networks to integrate stochastic fluctuations with environmental signals to generate and control advantageous phenotypic diversity in clonal populations.