Motile Characteristics of 9+2 and 9+1 Flagellar Axonemes of Crithidia Oncopelti

Crithidia oncopelti flagella were progressively solubilized by exposure to solutions containing the detergent Nonidet P42. During the course of the exposure, demembranated flagella were obtained that first had 9+2 axonemes, then 9+1, followed by 9+0. Finally, cylinders of A microtubules were obtained. The 9+2 and 9+1 flagella could be reactivated, indicating that the central complex does not have to be intact to allow wave propagation in this preparation. 9+0 axonemes could not be reactivated. Fourier analysis showed that the waveforms of the 9+2 and 9+1 axonemes were essentially the same, conforming to a meander shape. This shape is significantly different from the arc-line waves seen on in vivo flagella and indicates that (a) the membrane plays a significant role in the regulation of this parameter and (b) the passive elastic resistance of the microtubules in demembranated flagella has an important influence on bend patterns. The responses of 9+2 and 9+1 demembranated flagella to ATP were essentially the same, demonstrating that the extraction process had not affected the dynein-tubulin interaction. The central complex in Crithidia may be responsible for controlling the direction of wave propagation.