scholarly journals Calcium Influx Mediates the Voltage-Dependence of Sperm Entry into Sea Urchin Eggs

2000 ◽  
Vol 223 (2) ◽  
pp. 449-462 ◽  
Author(s):  
David H. McCulloh ◽  
Pedro I. Ivonnet ◽  
David Landowne ◽  
Edward L. Chambers
Keyword(s):  
Sea Urchin ◽  
Voltage Dependence ◽  
Calcium Influx ◽  
Sea Urchin Eggs ◽  
Sperm Entry

scholarly journals Thimerosal reveals calcium-induced calcium release in unfertilised sea urchin eggs

Zygote ◽  
1993 ◽  
Vol 1 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Alex McDougall ◽  
Isabelle Gillot ◽  
Michael Whitaker
Keyword(s):  
Sea Urchin ◽  
Calcium Release ◽  
Calcium Influx ◽  
Calcium Transient ◽  
Cell Types ◽  
Egg Activation ◽  
Free Calcium ◽  
Slow Increase ◽  
Sea Urchin Eggs ◽  
Calcium Induced Calcium Release

SummaryThe fertilisation calcium wave in sea urchin eggs triggers the onset of development. The wave is an explosive increase in intracellular free calcium concentration that begins at the point of sperm entry and crosses the egg in about 20 s. Thimerosal is a sulphydryl reagent that sensitises calcium release from intracellular stores in a variety of cell types. Treatment of unfertilised eggs with thimerosal causes a slow increase that results eventually in a large, spontaneous calcium transient and egg activation. At shorter times after thimerosal treatment, egg activation and the calcium transient can be triggered by calcium influx through voltage-gated calcium channels, a form of calcium-induced/calcium release (CICR). Thimerosal treatment also reduces the latency of the fertilisation calcium response and increases the velocity of the fertilisation wave. These results indicate that thimerosal can unmask CICR in sea urchin eggs and suggest that the ryanodine receptor channel based CICR may contribute to explosive calcium release during the fertilisation wave.

scholarly journals Sperm Receptivity in Sea Urchin Oocytes and Eggs

1985 ◽  
Vol 118 (1) ◽  
pp. 85-97 ◽  
Author(s):  
BRIAN DALE
Keyword(s):  
Experimental Data ◽  
Sea Urchin ◽  
Resting Potential ◽  
Entry Site ◽  
Sea Urchin Eggs ◽  
Interaction Sites ◽  
Sperm Entry ◽  
Electrophysiological Method ◽  
Cytoplasmic Maturation ◽  
Two Parameters

An electrophysiological method for studying the receptivity to spermatozoa of sea urchin eggs and oocytes is described. Pairs of adjacent oocytes and eggs, with intact jelly layers, were impaled and simultaneously exposed to a known concentration of spermatozoa. Two parameters were studied. The time from insemination to the first successful collision (as indicated by a step depolarization across the egg plasma membrane) and the total number of successful collisions. Sperm densities of 107ml−1 were used, which ensured almost immediate interaction between several thousand spermatozoa and each female gamete. In all cases, under control conditions, the oocyte was more receptive to spermatozoa than was the egg, giving rise to the first electrical event at about 5 s post-insemination, compared to about 13 s for the egg. In addition, whereas 10–15 spermatozoa usually entered the oocyte, only one entered the egg. The low receptivity of eggs appears to be independent of resting potential. Cytoplasmically immature eggs or mature eggs briefly exposed to nicotine, strychnine, choline or Tris tend to be polyspermic and have comparable receptivity to oocytes. The data suggest that there are limited number of viable interaction sites on the oocyte surface and that during cytoplasmic maturation these sites are rendered less receptive. In the mature egg there may be one preferential sperm entry site. This hypothesis is consistent with the experimental data and would explain why sea urchin eggs are usually monospermic at high sperm densities.

scholarly journals Identification of polysialic acid-containing glycoprotein in the jelly coat of sea urchin eggs. Occurrence of a novel type of polysialic acid structure.

1994 ◽  
Vol 269 (36) ◽  
pp. 22712-22718 ◽  
Author(s):  
S. Kitazume ◽  
K. Kitajima ◽  
S. Inoue ◽  
F.A. Troy ◽  
J.W. Cho ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Polysialic Acid ◽  
Sea Urchin Eggs ◽  
Jelly Coat ◽  
Acid Structure

scholarly journals Dynein isoforms in sea urchin eggs.

1988 ◽  
Vol 263 (14) ◽  
pp. 6759-6771 ◽  
Author(s):  
M E Porter ◽  
P M Grissom ◽  
J M Scholey ◽  
E D Salmon ◽  
J R McIntosh
Keyword(s):  
Sea Urchin ◽  
Sea Urchin Eggs
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