Flagellar wave reversal in the kinetoplastid flagellate Crithidia oncopelti

Summary— Living Crithidia oncopelti cells swim through their environment by means of tip‐to‐base waves on their single flagellum. The cells are able to re‐orient themselves by using a short burst of asymmetrical base‐to‐tip waves. All points on a flagellum are capable of initiating waves. Placing a population of cells in a medium of high viscosity initially produces a large number of organisms beating in the reverse mode. An individual cell has a random “switching” behaviour. Viscosity affects the frequency of forward and reverse waves in different ways. The concentration of free Ca++ ions determines the direction of wave propagation in reactivated axonemes. Calmodulin may play a role in mediating the Ca++ dependence of wave direction.