scholarly journals Inhibition of secretory granule discharge during exocytosis in sea urchin eggs by polymer solutions.

1987 ◽  
Vol 389 (1) ◽  
pp. 527-539 ◽  
Author(s):  
M Whitaker ◽  
J Zimmerberg
Keyword(s):  
Secretory Granule ◽  
Sea Urchin ◽  
Polymer Solutions ◽  
Sea Urchin Eggs

How calcium may cause exocytosis in sea urchin eggs

1987 ◽  
Vol 7 (5) ◽  
pp. 383-397 ◽  
Author(s):  
Michael Whitaker
Keyword(s):  
Membrane Fusion ◽  
Lipid Bilayers ◽  
Secretory Granule ◽  
Sea Urchin ◽  
Surface Potential ◽  
Membrane Lipids ◽  
Electrical Potential ◽  
Sea Urchin Eggs ◽  
Granule Membrane

The process of secretory granule-plasma membrane fusion can be studied in sea urchin eggs. Micromolar calcium concentrations are all that is required to bring about exocytosis in vitro. I discuss recent experiments with sea urchin eggs that concentrate on the biophysical aspects of granule-membrane fusion. The backbone of biological membranes is the lipid bilayer. Sea urchin egg membrane lipids have negatively charged head groups that give rise to an electrical potential at the bilayer-water interface. We have found that this surface potential can affect the calcium required for exocytosis. Effects on the surface potential may also explain why drugs like trifluoperazine and tetracaine inhibit exocytosis: they absorb to the bilayer and reduce the surface potential. The membrane lipids may also be crucial to the formation of the exocytotic pore through which the secretory granule contents are released. We have measured calcium-induced production of the lipid, diacylglycerol. This lipid can induce a phase transition that will promote fusion of apposed lipid bilayers. The process of exocytosis involves the secretory granule core as well as the lipids of the membrane. The osmotic properties of the granule contents lead to swelling of the granule during exocytosis. Swelling promotes the dispersal of the contents as they are extruded through the exocytotic pore. The movements of water and ions during exocytosis may also stabilize the transient fusion intermediate and consolidate the exocytotic pore as fusion occurs.

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

Expression of Nox genes in rat organs, mouse oocytes, and sea urchin eggs

DNA Sequence ◽  
2005 ◽  
Vol 16 (2) ◽  
pp. 83-88 ◽  
Author(s):  
Yoshiro Maru ◽  
Takeshi Nishino ◽  
Katsuko Kakinuma
Keyword(s):  
Sea Urchin ◽  
Sea Urchin Eggs ◽  
Mouse Oocytes ◽  
Rat Organs
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