Scaling of Fluctuations and Energy in Bacterial Growth and Division

在这个项目中，PI将结合实验和理论来测量和理解各种观测量的波动与生命系统对设计（脉动）扰动的反应之间的关系。该方法以PI开发和实施的一项独特技术为中心，将微流体、单细胞成像、定量分析和新月形茎杆菌生长和分裂的随机建模相结合。该项目试图采用这种方法来评估生长控制模型以及细胞交换能量、速度和准确性的程度；确定在稳定和变化条件下约束细胞周期统计的关系；设计一个系统，在这个系统中，一个群体中的细胞之间的相互作用可以被调节，以研究自发的对称性破坏。这些目标对于建立远离平衡的系统的基本物理学非常重要。它们还提供了一些例子，说明如何利用比例和波动关系对监管动态提供直接约束。通过这种方式，这些研究补充了收集分子浓度和相互作用信息的常用生物学方法。研究者试图将该项目的核心概念，例如超越平均值研究统计分布的重要性，带给对生命系统感兴趣的更广泛的受众。为此，PI将开发一门暑期课程，通过动手实验和自我指导的网络教程，向高中教师介绍生物系统中概率、能量和熵的基本概念。该项目由物理系的生命系统物理学项目和分子与细胞生物科学系的细胞动力学和功能项目共同支持。

In this project, the PI will integrate experiment and theory to measure and understand the relationship between fluctuations of various observed quantities and the responses of a living system to designed (pulsatile) perturbations. The approach centers on a unique technology that the PI has developed and implemented, combining microfluidics, single-cell imaging, quantitative analysis, and stochastic modeling of growth and division of Caulobacter crescentus. The project seeks to employ this approach to evaluate models for growth control and the degree to which cells trade energy, speed, and accuracy; identify relations constraining the statistics of cell-cycle periods under steady and changing conditions; and engineer a system in which the interactions between cells in a population can be modulated to study spontaneous symmetry breaking. These goals are important for establishing the fundamental physics of systems far from equilibrium. They also provide examples as to how scaling and fluctuation relations can be used to provide direct constraints on regulatory dynamics. In this way, these studies complement common biological methods for assembling information about molecular concentrations and interactions. The investigator seeks to bring core concepts of the project, such as the importance of going beyond averages to study statistical distributions, to a broader audience interested in living systems. To this end, the PI will develop a summer course to introduce high school teachers to basic concepts in probability, energy, and entropy in biological systems through hands-on experimentation and self-guided web-based tutorials.This project is being jointly supported by the Physics of Living Systems program in the Division of Physics and the Cellular Dynamics and Function Program in the Division of Molecular and Cellular Biosciences.