Measurements of ooplasmic pCa in fertilized eggs of the locust, Locusta migratoria, and a role for external calcium in experimental activation of unfertilized eggs

The role of Ca2+ in activation and early development of locust eggs was examined through measurement of ooplasmic Ca2+ levels before and after fertilization, and through experimental activation of unfertilized eggs. Ooplasmic pCa (i.e. the negative logarithm of Ca2+ activity) measured in intact eggs decreased from 5.35 before fertilization, to 4.77 and 3.00 by 1 day and 3 days after fertilization, respectively. pCa was also determined for …