Fig. 5. Ciliary reversal in response to UV application. Light was applied to cilia at the anterior of a cell loaded with NP-EGTA in Ca²⁺-chelating medium. (A) A representative result in which the distance l is zero. The distance l was determined as indicated in the inset in (B). Before, prior to UV application; after, following UV application. UV light was applied to the area indicated by the circle. Arrows indicate direction of the cilia within or outside the area of UV application. Bar, 20 µm. This series of images is shown in Movie 1. (B) Relationship between the distance l from the rim of the area to which UV light was applied (circled) to the cell surface and the angle of ciliary reversal. The angle of ciliary reversal was calculated by subtracting the angle of the cilia prior to UV application from that after UV application.