Spontaneous recovery after experimental manipulation of the plane of beat in sperm flagella.

It is generally accepted that the oscillatory beating characteristic of sperm flagella is the result of an ATP-induced sliding between the doublet microtubules of the flagellar axoneme, with these longitudinal forces being converted into a lateral bending moment by resistive components of the structure that limit the displacement. However, little is known about the mechanisms that regulate this sliding among the nine doublets of the cylindrical axoneme to produce the coordinated planar bending waves required for efficient sperm propulsion. We have investigated these mechanisms with a new procedure in which the sperm head is held in the tip of a vibrating micropipette. Data obtained by gradually rotating the plane of imposed vibration around the sperm axis indicate that the pattern of active sliding between the outer doublet tubules can rotate relative to the sperm head, and suggest that this active sliding is regulated in part by the central tubule complex.