Self-Organizing Ciliary Beating and its Control in Chlamydomonas

Syracuse University, Syracuse NY

Investigators

Abstract

In this project the PIs will determine the motor-generated shear forces and doublet sliding in the biciliated unicellular alga Chlamydomonas reinhardtii under wide range of conditions with the goal of establishing the correct mechanism for self-organizing beating structure. First the PIs will record long durations of high temporal and spatial resolution images of ciliary beating using electron-multiplying CCD camera. Next they will determine accurately the drag force exerted by the fluid along the cilium using a slender body theory for low Reynolds number flows. The force generated by motors along the length of a cilium will then be determined by balancing the hydrodynamic drag to internal forces due to sliding and bending. The precise images of the cilia will also allow the PIs to determine the relative sliding of the doublets. The force-sliding data will be used to test various models of self-organizing beating structure as well as to determine the dynamics of the basal body that connects the two cilia to the cell body. The proposed study will add a significant tool for determining the active internal forces generated during ciliary beating. This in-vivo technique will complement the in-vitro molecular genetic, electron microscopy, atomic force microscopy (AFM), and sliding assay techniques currently used to understand the physiology of ciliary beating. Several graduate students will be trained in interdisciplinary research and to work as a team with several advisers. They will participate in all phases including experiment development, data collection, data analysis, and modeling. Undergraduate students will significantly aid the project by characterizing individual ciliary mutants that have mechanical or control function defects and will learn to use AFM. High school students will assist with mutants. The physics of cilia will be incorporated in undergraduate and graduate courses.