scholarly journals A COMPARATIVE STUDY OF THE ISOLATION OF THE CORTEX AND THE ROLE OF THE CALCIUM-INSOLUBLE PROTEIN IN SEVERAL SPECIES OF SEA URCHIN EGG

1969 ◽  
Vol 41 (1) ◽  
pp. 133-144 ◽  
Author(s):  
R. E. Kane ◽  
R. E. Stephens
Keyword(s):  
Comparative Study ◽  
Sea Urchin ◽  
Protein Composition ◽  
Cortical Region ◽  
Cortical Granules ◽  
Divalent Ions ◽  
Sea Urchin Egg ◽  
Protein Gelation ◽  
Isolated Cortex

A comparative study was made of the isolation of the cortex in the eggs of several sea urchin species. Since the isolation method developed by Sakai depends on the presence of magnesium in the medium, the protein composition of the cortex was investigated to determine whether the protein component of the egg described by Kane and Hersh which is gelled by divalent ions, is present in these cortices. Isolation of the cortex was found to require the same divalent ions at the same concentrations as protein gelation, and in the eggs of some species much of the gel protein of the cell was found in the isolated cortical material. In the eggs of other species a smaller fraction of this protein was found in the isolated cortex, although it was more concentrated there than in the endoplasm, and in one species this protein appeared to be uniformly distributed throughout the cell. These results indicate that this protein is localized in the cortical region of the eggs of some species of sea urchin, possibly in the cortical granules, but also point up the fact that results from one species cannot be uncritically extrapolated to others.

scholarly journals pH regulates the polymerization of actin in the sea urchin egg cortex.

1979 ◽  
Vol 83 (1) ◽  
pp. 241-248 ◽  
Author(s):  
D A Begg ◽  
L I Rebhun
Keyword(s):  
Sea Urchin ◽  
Actin Filaments ◽  
Actin Polymerization ◽  
Filamentous Actin ◽  
Cortical Granules ◽  
Isolation Medium ◽  
Large Numbers ◽  
Sea Urchin Egg ◽  
Isolated Cortex ◽  
Egg Cortex

The state of actin in the isolated cortex of the unfertilized sea urchin egg can be controlled by experimentally manipulating the pH of the isolation medium. Cortices isolated at the pH of the unfertilized egg (6.5--6.7) do not contain filamentous actin, while those isolated at the pH of the fertilized egg (7.3--7.5) develop large numbers of microvilli which contain bundles of actin filaments. Cortices that are isolated at pH 6.5 and then transferred to isolation medium buffered at pH 7.5 also develop actin filaments. However, the filaments are not arranged in bundles and microvilli do not form. Although the cortical granules in cortices isolated at pH 6.5 discharge at a free Ca++ concentration of approximately 10 micrometer, actin polymerization is not induced by increasing the Ca++ concentration of the isolation medium. These results suggest that the increase in cytoplasmic pH which occurs following fertilization induces the polymerization of actin in the egg cortex.

scholarly journals Role of the Fyn Kinase in Calcium Release during Fertilization of the Sea Urchin Egg

2000 ◽  
Vol 225 (1) ◽  
pp. 253-264 ◽  
Author(s):  
W.H. Kinsey ◽  
S.S. Shen
Keyword(s):  
Sea Urchin ◽  
Calcium Release ◽  
Fyn Kinase ◽  
Sea Urchin Egg

scholarly journals Poisson-distributed active fusion complexes underlie the control of the rate and extent of exocytosis by calcium.

1996 ◽  
Vol 134 (2) ◽  
pp. 329-338 ◽  
Author(s):  
S S Vogel ◽  
P S Blank ◽  
J Zimmerberg
Keyword(s):  
Poisson Process ◽  
Sea Urchin ◽  
Physiological Responses ◽  
Cortical Granule ◽  
Cortical Granules ◽  
Granule Exocytosis ◽  
Calcium Dependence ◽  
Sea Urchin Egg ◽  
High Calcium ◽  
Cortical Granule Exocytosis

We have investigated the consequences of having multiple fusion complexes on exocytotic granules, and have identified a new principle for interpreting the calcium dependence of calcium-triggered exocytosis. Strikingly different physiological responses to calcium are expected when active fusion complexes are distributed between granules in a deterministic or probabilistic manner. We have modeled these differences, and compared them with the calcium dependence of sea urchin egg cortical granule exocytosis. From the calcium dependence of cortical granule exocytosis, and from the exposure time and concentration dependence of N-ethylmaleimide inhibition, we determined that cortical granules do have spare active fusion complexes that are randomly distributed as a Poisson process among the population of granules. At high calcium concentrations, docking sites have on average nine active fusion complexes.

Purification of cortical granules from unfertilized sea urchin egg homogenates by zonal centrifugation

1972 ◽  
Vol 29 (3) ◽  
pp. 307-320 ◽  
Author(s):  
H. Schuel ◽  
W.L. Wilson ◽  
R.S. Bressler ◽  
J.W. Kelly ◽  
J.R. Wilson
Keyword(s):  
Sea Urchin ◽  
Cortical Granules ◽  
Sea Urchin Egg

scholarly journals DIRECT ISOLATION OF THE HYALINE LAYER PROTEIN RELEASED FROM THE CORTICAL GRANULES OF THE SEA URCHIN EGG AT FERTILIZATION

1970 ◽  
Vol 45 (3) ◽  
pp. 615-622 ◽  
Author(s):  
R. E. Kane
Keyword(s):  
Protein Content ◽  
Sea Urchin ◽  
Insoluble Fraction ◽  
Glycerol Solution ◽  
Cortical Granules ◽  
Simple Method ◽  
Quantitative Measurements ◽  
Hawaiian Species ◽  
Sea Urchin Egg

Treatment of the eggs of the sea urchin with a 1 M solution of glycerol at fertilization allows the recovery from this solution of the protein released from the cortical granules, including that which would normally give rise to the hyaline layer. The calcium-gelable protein previously extracted from whole eggs and from isolated cortical material was found to be present in the glycerol solution, confirming its localization in the cortical granules and its role in the hyaline layer. Quantitative measurements on the eggs of two Hawaiian species, Colobocentrotus atratus and Pseudoboletia indiana, which have the widest variation in the gel protein content, demonstrated that a proportionate amount of this material was released at fertilization in these species, which correlates with the thickness of the hyaline layer in the two cases. In addition, the calcium-insoluble fraction of Sakai can be extracted from these eggs after removal of the hyaline protein by glycerol, showing that this is a different material. A simple method for the separation of the hyaline protein from the calcium-insoluble fraction in solution is provided.

scholarly journals THE MEMBRANE CAPACITANCE OF THE SEA URCHIN EGG

1957 ◽  
Vol 3 (1) ◽  
pp. 103-110 ◽  
Author(s):  
Lord Rothschild
Keyword(s):  
Plasma Membrane ◽  
Sea Urchin ◽  
Sea Water ◽  
Unit Area ◽  
Membrane Capacitance ◽  
Percentage Reduction ◽  
Cortical Granules ◽  
Sea Urchin Egg

1. The surface of the unfertilized sea urchin egg is folded and the folds are reversibly eliminated by exposing the egg to hypotonic sea water. If the plasma membrane is outside the layer of cortical granules, unfolding may explain why the membrane capacitance per unit area decreases (and does not increase) when a sea urchin egg is put into hypotonic sea water. 2. The degree of surface folding markedly increases after fertilization, which provides an explanation for the increase in membrane capacitance per unit area observed after fertilization. 3. The percentage reduction in membrane folding in fertilized eggs after immersion in hypotonic sea water is probably sufficient to explain the decrease in membrane capacitance per unit area observed in these conditions.

Immunocytochemical evidence suggesting heterogeneity in the population of sea urchin egg cortical granules

1988 ◽  
Vol 125 (1) ◽  
pp. 1-7 ◽  
Author(s):  
John A. Anstrom ◽  
Jia E. Chin ◽  
David S. Leaf ◽  
Annette L. Parks ◽  
Rudolf A. Raff
Keyword(s):  
Sea Urchin ◽  
Cortical Granules ◽  
Sea Urchin Egg
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