Impaired ciliary bending in hydin mutants. Sequential still images of ependymal cilia from the wild type (+/+; a) and a hy3/hy3 mutant (−/−; b). The time is indicated in milliseconds. In b, three moving cilia are tracked with arrowheads. Bars, 5 μm. (c–f) Ciliary waveform in the wild type (c and d) and Hydin mutants (e and f). Line tracings of the effective stroke (c and e) and the recovery stroke (d and f) are shown. In c and d, the frame numbers are indicated. Ciliary positions are shown every 5 or 10 ms for the wild type and mutant, respectively. The line tracings are from different videos than those shown in panels a and b; e and f are from an OVE459 animal. Arrows indicate the direction of movement of the cilia.