Physics of Motility of Bacteria Living in Mucus Gels

粘液凝胶中细菌运动的物理学

• 批准号: 1058648
• 负责人: Rama Bansil
• 金额: $ 30万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-15 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1058648&HistoricalAwards=false
• 关键词: Physics; Motility; Bacteria; Living; Mucus

The focus of the proposed research is to understand the fundamental physics of bacterial motility in a non-Newtonian, viscoelastic gel and to correlate the motility with the viscoelastic properties of the medium. Using the ulcer causing bacterium H. pylori in mucin gels we will explore two regimes of motion: translational motion in solutions at neutral pH, and pure rotation without translation in gels at low pH. We will apply state-of-the-art imaging techniques such as two-photon microscopy and single and multi-particle tracking for quantitative measurements of the dynamics of the motion of the bacterium and its impact on the local micro-rheology of its environment. Global or bulk changes in the mechanical and rheological properties of the bacteria infected gel will be determined by oscillatory shear rheology. Comparative studies of the wild-type H. pylori bacteria with mutants deficient in specific receptors or flagella, as well as with different body shapes, will enable us to assess the effect of the many variables at play in this complex living system. The experimental studies will be complemented by computational analysis and theoretical modeling of bacterial motility and flagella dynamics in gels to provide quantitative estimates of the velocity, forces, and torques involved in the motion and understand the underlying physics of how the motion correlates with the viscoelasticity. The results have potential relevance to many biomedical applications where motility in a gel plays a key role, such as in the infection of stomach mucus by H. pylori which leads to ulcers and cancer, to culturing of bacteria and cells in 3-dimensional gel matrices, in the design of bacterial resistant hydrogels for artificial tissues, and in the development of nano- and microscale swimmers and rotators. The research project, involving collaborators with expertise in theoretical physics, biomedical imaging, microbiology, and gastroenterology, will provide a unique opportunity for multidisciplinary training of graduate and undergraduate students in the areas of biophysics, fluid dynamics and microbiology, biochemistry and molecular biology. Videos on bacterial motility and simple analysis tools will be developed for use in undergraduate courses and for demonstration purposes. We will take advantage of the diversity of our team, and the broad appeal of the research topic, to do outreach activities involving presentations to a broader audience, including local high schools, and minority and other community groups and to recruit women and minority undergraduate and high school students to participate in the research.

该研究的重点是了解非牛顿粘弹性凝胶中细菌运动的基本物理学，并将运动与介质的粘弹性特性联系起来。利用黏液凝胶中引起溃疡的幽门螺杆菌，我们将探索两种运动机制：中性pH溶液中的平移运动，以及低pH凝胶中不平移的纯旋转。我们将应用最先进的成像技术，如双光子显微镜和单粒子和多粒子跟踪，定量测量细菌运动的动力学及其对环境局部微流变学的影响。细菌感染凝胶的机械和流变特性的整体或整体变化将由振荡剪切流变学决定。对野生型幽门螺杆菌与缺乏特定受体或鞭毛的突变体以及不同体型进行比较研究，将使我们能够评估在这个复杂的生命系统中起作用的许多变量的影响。实验研究将辅以细菌运动和鞭毛动力学的计算分析和理论建模，以提供运动中涉及的速度，力和扭矩的定量估计，并了解运动如何与粘弹性相关的潜在物理。这些结果与许多生物医学应用具有潜在的相关性，其中凝胶中的运动性起着关键作用，例如幽门螺杆菌导致胃溃疡和癌症的胃粘液感染，细菌和细胞在三维凝胶基质中的培养，用于人造组织的细菌抗性水凝胶的设计，以及纳米和微尺度游泳者和旋转器的开发。该研究项目涉及理论物理学、生物医学成像、微生物学和胃肠病学方面的专家，将为生物物理学、流体动力学和微生物学、生物化学和分子生物学领域的研究生和本科生提供一个独特的多学科培训机会。将开发有关细菌运动和简单分析工具的视频，用于本科课程和演示目的。我们将利用我们团队的多样性，以及研究课题的广泛吸引力，开展外联活动，包括向更广泛的受众进行演讲，包括当地高中、少数民族和其他社区团体，并招募女性和少数民族本科生和高中生参与研究。