Direct evidence for tension development between flagellar doublet microtubules.

In this study of isolated ribbons of flagellar doublet microtubules, we demonstrate that a resistance to sliding exists in the interdoublet gap. By photolytically releasing ATP from caged ATP, it has been possible to follow closely the responses of individual specimens. Distortion of the helical superstructure of the doublets, most often by a reduction in helical pitch, is interpreted as revealing the development of tension between doublets. Tension does not develop in the presence of vanadate.