Research Summary

Collective behavior of isolated flagellar axonemes of Chlamydomonas

Eukaryotic flagella or cilia are long filament shaped organelles responsible for setting up fluid flow through their periodic undulatory motion. Our current understanding of this organelle mainly rests on genetic, molecular and ultrastructural studies. Despite the detailed knowledge of structure of cilia, we do not know how its building blocks act together to cause beating. The problem becomes even more intractable when a collection of cilia beat together because their collective behavior simply cannot be extrapolated from the knowledge of the dynamic beat pattern of a single cilium. We have taken a complementary viewpoint to the molecular scale studies of the past. We focus on the role of macroscopic stresses, both in the cilium and in the surrounding fluid, which interact to provide the drive for ciliary motion. It is this coupling between the external fluid and the cilium that has been overlooked in the past. Isolated flagellar axonemes from Chlamydomonas, a single celled biflagellate algae, are an ideal model system for such studies. We will use particle velocimetry and other imaging techniques along with theoretical modeling to identify the role of fluid flow and its competition with the underlying biochemical regulation.

Figure Legend: Beat averaged flow field of a Chlamydomonas cell measured using particle image velocimetry.