Fig. 8. Changes in cell function in response to UV application. Light was applied to the inner part of the anterior of a Paramecium cell loaded with NP-EGTA in Ca²⁺-containing medium. (A) A series of images around the area of UV application. The time course is indicated above each picture. UV light was applied to the area indicated by the circle in the picture marked 0.13 s. UV light was somewhat scattered by cytoplasmic particles. Contraction of the cell body in response to UV application was observed at the area of UV application. Arrowheads mark trichocysts released via exocytosis, indicating [Ca²⁺]_i at the neighboring basal bodies; arrows, direction of cilia, whose basal bodies were inside or outside the area of trichocyst exocytosis. The series is a typical result from a total of 16 experiments. Bar, 20 µm. This series of images are indicated in Movie 5, which is slowed to 1/3 of the original speed. (B) Temporal relation of ciliary angle measured from A. The time course in B matches the time indicated at the top of each picture in A. The period of UV application is indicated by a black bar; the triangle indicates the time of trichocyst exocytosis. Solid line, angle of a cilium whose basal body was within the area of trichocyst exocytosis; dashed line, angle of a cilium whose basal body was outside the area of trichocyst exocytosis.

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