Whole-cell flagellum-based motility studied using back focal plane interferometry in a laser trap transducer

The biflagellated alga Chlamydomonas reinhardtii undergoes light-directed motility by controlling the beating patterns of its flagella. The molecular mechanisms of this control system are debated. To help understand the process we are using a laser trap transducer to capture single, swimming Chlamydomonas by their contractile vacuole - the organelle that allows them to regulate cell volume. Trapping the cell by this organelle enables us to accurately and reproducibly measure the swimming force, beat frequencies and waveforms generated by the flagella. This is a unique approach to understanding the motor mechanisms and regulation of flagella in intact cells.