Figure 3.

Example of a Ca²⁺ signal evoked in an egg. Similar to Figure 2, but for an experiment performed in an egg. In this case the UV illumination was on between t = 11.2 s and t = 28 s and between t = 112 s and t = 128.8 s. At t ~ 12.9 s the Ca²⁺ release becomes apparent (A). The Ca²⁺ distribution is more spatially uniform than in the oocyte. The wave propagates (B,C) and the fluorescence keeps on increasing while the UV light is on (D). Approximately 16 s after the UV flash is turned off (t = 44.8 s), the fluorescence has not reached the basal level yet (E). Ca²⁺ puffs are not observed in between the two UV flashes (F). The white boxes indicate two regions analyzed in Figure 4.