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Fluid-mechanical Interaction of a Bacterial Swimmer with Flagella and Bacterial Chemotaxis

细菌游泳者与鞭毛和细菌趋化性的流体机械相互作用

基本信息

批准号：
1853591
负责人：
Sookkyung Lim
金额：
$ 15万
依托单位：
University of Cincinnati Main Campus
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-08-01 至 2023-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1853591&HistoricalAwards=false
关键词：
Fluid mechanical Interaction Bacterial Swimmer

项目摘要

This project will develop a versatile model of a self-propelled microswimmer to understand the underlying swimming mechanisms of the complex hydrodynamics of flagellated bacteria such as Escherichia coli and Salmonella typhimurium. Bacterial motility is profoundly important in human health and medicine, as it results in the spread of infections, including those further complicated by biofilm formation. This project will focus on addressing unanswered biological questions about bacterial swimming and the chemotactic behavior in viscous fluids. For example: How do bacterial flagella actually bundle and unbundle? How is bacterial motility in shear flow near surfaces modified and related to bacterial pathogenesis? The goal of this project is twofold. First, mathematical models of bacterial swimmers that are true to biology shall be developed. Second, these models will be validated by comparing them to experimental data, and will be used to make predictions for further experiments. The results obtained from this research on free swimming bacteria in viscous fluids may provide new information about the spread of infections and biofilm formation, and may also help to design nanomachines that are self-propelled by flagella.The mathematical method developed in this project enables to build a complete model of a bacterial swimmer that includes a rod-shaped cell body, rotary motors, and flagella (a compliant hook and a flexible helical filament) so that the model can deal simultaneously with all complex aspects of the fluid-mechanical interaction of the bacterial swimmer. In addition, the mathematical model organism will execute a three-dimensional unbiased random walk following Poisson process. This project will use an improved version of the regularized Stokes formulation combined with the nonstandard Kirchhoff rod theory and the neutrally buoyant rigid cell body dynamics in order to describe the fluid-mechanical interaction of the cell model. This model will also be used to investigate positive rheotaxis near a surface, which can affect bacterial transport in biomedical settings such as the urinary tract and catheters. The methods and tools developed in this project will find many applications in biological fluids, where thin elastic structures together with rigid bodies interact with fluids, including sperm motility and bacterial pathogens such as H. pylori in the stomach.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目将开发一种自走式微型游泳器的多功能模型，以了解大肠杆菌和鼠伤寒沙门氏菌等有鞭毛细菌的复杂流体动力学的潜在游泳机制。细菌运动对于人类健康和医学非常重要，因为它会导致感染的传播，包括因生物膜形成而进一步复杂化的感染。该项目将重点解决有关细菌游动和粘性液体中趋化行为的未解答的生物学问题。例如：细菌鞭毛实际上如何捆绑和解开？表面附近剪切流中的细菌运动如何改变并与细菌发病机制相关？该项目的目标是双重的。首先，应开发符合生物学的细菌游动者的数学模型。其次，这些模型将通过与实验数据进行比较来进行验证，并将用于为进一步的实验做出预测。这项关于粘性液体中自由游动细菌的研究获得的结果可能会提供有关感染传播和生物膜形成的新信息，也可能有助于设计由鞭毛自行驱动的纳米机器。该项目中开发的数学方法能够建立细菌游泳者的完整模型，其中包括杆状细胞体、旋转电机和鞭毛（顺应钩和柔性螺旋丝），以便该模型可以同时处理细菌游泳者流体机械相互作用的所有复杂方面。此外，数学模型有机体将遵循泊松过程执行三维无偏随机游走。该项目将使用改进版本的正则化斯托克斯公式，结合非标准基尔霍夫杆理论和中性浮力刚性细胞体动力学来描述细胞模型的流体-机械相互作用。该模型还将用于研究表面附近的正流趋性，这可能影响生物医学环境中的细菌转运，例如尿道和导管。该项目开发的方法和工具将在生物流体中找到许多应用，其中薄弹性结构和刚体与流体相互作用，包括精子活力和胃中幽门螺杆菌等细菌病原体。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。