STUDIES OF THE FORCE SENSITIVITY OF INDIVIDUAL SWIMMING PROTISTS USING MAGNETIC FORCE BUOYANCY VARIATION

在这项建议中，PI将研究力感知机制在单细胞生物的代表：草履虫。草履虫克服了沉积的倾向，在向上游泳时比向下游泳时施加更大的推动力。这一行为表明草履虫可以感觉到压力差小于大气压力的1/10,000,000的力。为了调查这种敏感的力反应的未知来源，PI将对草履虫施加力，并测量它们的游泳轨迹的几何形状和速度如何变化。它们的轨迹特征将揭示它们的力感应机制。这些方法将使用佛罗里达州塔拉哈西的国家高磁场实验室产生的强磁场。磁场还将被用来指导和遏制游泳草履虫，以便他们可以对个别游泳者进行更长时间的研究。除了细胞力感应领域的工作者外，对细胞运动特别是低雷诺数游泳感兴趣的科学家群体也将对这一结果感兴趣。拟议的实验将作为布朗大学一名博士生的博士论文工作。它将使学生接触到实验研究的方方面面，包括实验设计、数据采集和分析以及结果传播。学生将发展生物物理学方面的专业知识，包括细胞中的机械转导和细胞运动性，这一培训将增强我们国家的科学和技术基础。

In this proposal the PI will study the force sensing mechanism in a representative of the unicellular organisms: paramecia. Paramecium fights its tendency to sediment exerting a stronger propulsive force when it swims upward than when it swims downward. This behavior indicates that paramecia can sense forces corresponding to pressure differences that are less than 1/10,000,000th of atmospheric pressure. To investigate the unknown source of this sensitive force response the PI will apply forces on paramecia and measuring how the geometry and speed of their swimming trajectories change. The characteristics of their trajectories will reveal their force sensing mechanisms. The methods will employ the intense magnetic fields generated at the National High Magnetic Field Laboratory in Tallahassee, Florida. Magnetic fields will also be used to direct and contain the swimming paramecia so that they can study individual swimmers for extended periods of time. In addition to workers in the cell force sensing field, the results will be of interest to the community of scientists interested in cell motility and in particular, low Reynolds number swimming. The proposed experiments will serve as the PhD thesis work for a PhD student at Brown University. It will expose the student to all aspects of experimental research including experimental design, data acquisition and analysis, and results dissemination. The student will develop expertise in biophysics including mechano-transduction in cells and cell motility and this training will augment our nations science and technology base.