Figure 2.
Cytosolic Ca2+ during the healing of a wound. A sea urchin egg was injected with the fluorescent Ca2+ indicator calcium green dextran (10 kD; 20 μM final concentration). As in Fig. 1, a polylysine-coated microneedle was used to create a wound. There is a local rise in Ca2+ during wounding, but the rise diminishes rapidly. In view of the large gradient of Ca2+ from SW to cytosol, this is further indication of a rapid healing reaction. Images were obtained at 1-s intervals; consecutive images are shown except the last image, which was 15 s after wounding. The small dark circle near the center of the egg is an oil drop resulting from the calcium green dextran injection. Bar, 10 μm.