Quantitative analysis of the process and propagation of cortical granule breakdown in sea urchin eggs
| Autor: | Tatsuma Mohri, Yukihisa Hamaguchi |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Male
Microinjections Physiology Video Recording Cortical granule Inositol 1 4 5-Trisphosphate chemistry.chemical_compound Human fertilization biology.animal Animals Inositol Maximal rate Inositol phosphate Molecular Biology Sea urchin Ovum Sperm-Ovum Interactions chemistry.chemical_classification Microscopy biology Clypeaster japonicus Cell Biology General Medicine Anatomy chemistry Differential interference contrast microscopy Sea Urchins Biophysics Female |
| Zdroj: | Cell Structure and Function. 15:309-315 |
| ISSN: | 1347-3700 0386-7196 |
| DOI: | 10.1247/csf.15.309 |
| Popis: | Cortical granule breakdown in sea urchin eggs has been investigated with a video microscope system using Nomarski differential interference contrast optics, when induced by fertilization, microinjecting inositol 1,4,5-trisphosphate (IP3) or Ca-EGTA buffer solution into the egg, or perfusing a medium containing 1 mM Ca2+ to isolated cortices. The cortical granule increased up to 1.2 times in diameter and broke down within 40 msec. These values were almost constant among the three methods used to induce cortical granule breakdown. Upon fertilization, the cortical granule breakdown propagated over the egg surface at a speed of 3.3 microns/sec in Clypeaster japonicus eggs, which indicates that cortical granule breakdown propagated through the 3.3-microns-wide egg surface within 1 sec. In such a small area of the egg surface, however, it took much more than 1 sec for all cortical granules to break down because the maximal rate of breakdown was 7.6%/sec; that is, it took 9 sec and 18 sec for 50% and 90% respectively, of cortical granules to break down. Moreover, the rate did not simply decrease with time, and a shoulder was found during the reducing phase, which suggests that cortical granules are divided into fast and slow breakdown groups according to the responsiveness to the breakdown stimulus. The cortical granule breakdown induced by microinjecting the Ca-EGTA buffer and IP3 solutions propagated at 68 microns/sec and 35 microns/sec, respectively. The stimulus for cortical granule breakdown is discussed concerning the transient intracellular Ca2+ increase. |
| Databáze: | OpenAIRE |
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