. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. R. A. FLUCK X 104 quanta second"' ^m 2 (10X objective lens, no neutral density filter). To monitor the eggs during irra- diation, they were transilluminated with light from a quartz-halogen lamp, using a heat filter (KG5) and a 486 DF32 filter, and the images were recorded via a SIT cam- era (Dage/MTI) and a time-lapse videocassette recorder. To monitor the development of fertilized eggs after the first cell cycle, they were transferred to embryo rearing medium (17 mM NaCl; mM KCI; mM CaCl:; mM MgSCV, 0
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. R. A. FLUCK X 104 quanta second"' ^m 2 (10X objective lens, no neutral density filter). To monitor the eggs during irra- diation, they were transilluminated with light from a quartz-halogen lamp, using a heat filter (KG5) and a 486 DF32 filter, and the images were recorded via a SIT cam- era (Dage/MTI) and a time-lapse videocassette recorder. To monitor the development of fertilized eggs after the first cell cycle, they were transferred to embryo rearing medium (17 mM NaCl; mM KCI; mM CaCl:; mM MgSCV, g/1 methylene blue). When unfertilized eggs into which nl NP- EGTA had been injected were irradiated with UV light, they activated within 16 ± 3 s (X ± SD, n = 5), as evi- denced by the exocytosis of cortical vesicles. Exocytosis began within the irradiated region and spread as a wave over the rest of the egg. Eggs were photoactivated even after the light intensity was reduced 34-fold with a neutral density filter; but when a second neutral density filter was added, reducing the light intensity an additional , the eggs were not activated even after 3 min of continuous irradiation. Irradiation of unfertilized eggs that had not received NP-EGTA did not cause them to activate. Continued irradiation of photoactivated eggs caused both ooplasm and oil droplets to accumulate in and next to the irradiated zone (Fig. 1 A). Staining with rhodamine phalloidin showed that these accumulations of ooplasm contained filamentous actin (F-actin, Fig. IB). Such ac- cumulations of ooplasm and F-actin were identified in 18 eggs, 13 of which had been photoactivated and 5 of which had been fertilized. Moreover, the caps of ooplasm formed in eggs into which either nl or nl of NP-EGTA had been injected and in eggs that were irradiated either intermittently (5 s on/115 s off) with a high intensity of light or continuously with a 34-fold lower light intensity. However, when
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
