The role of divalent cations in activation of the sea urchin egg. I. Effect of fertilization on divalent cation content

1976 ◽  
Vol 198 (1) ◽  
pp. 65-77 ◽  
Author(s):  
Roobik Azarnia ◽  
Edward L. Chambers
Keyword(s):  
Sea Urchin ◽  
Divalent Cation ◽  
Divalent Cations ◽  
Cation Content ◽  
Sea Urchin Egg

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

Extracellular Calcium And Platelets

1981 ◽  
Author(s):  
P M Taylor ◽  
S Heptinstall
Keyword(s):  
Divalent Cation ◽  
Binding Sites ◽  
Divalent Cations ◽  
Extracellular Calcium ◽  
Time Dependent ◽  
Aggregation Process ◽  
Platelet Surface ◽  
Intracellular Pool ◽  
Continuous Movement

To gain more information on the role of extracellular Ca in platelet behaviour, the movement of 45Ca between plasma and platelets has been studied. Ttoo experimental procedures have been used: platelets were either studied in plasma that contained near-physiological levels of divalent cations or were studied in divalent cation-depleted plasma.There was a continuous movement of Ca from plasma into platelets when the latter were suspended in plasma that contained near-physiological levels of divalent cations. The iptake was linear with time (2.0 to 2.5 ng ion Ca/109 platelets/60 mins) and was faster at 37°C than at 25°C. The amount of Ca taken up by the platelets increased as the extracellular Ca level was increased and was markedly inhibited by Mg. Sr did not affect the uptake. EGTA displaced only a small amount of the Ca that associated with the plater lets which indicated that Ca was taken up into an intracellular pool rather than sinply bound to the platelet surface. The relevance of this movement of Ca into the cells to platelet behaviour has not been established.Studies using platelets suspended in divalent cation- depleted plasma shewed that extracellular Ca was in equilibrium with Ca bound at or near the platelet surface. The binding of Ca was time-dependent but saturable (0.30 to 0.50 ng ion Ca/109 platelets/30 mins), and the majority was readily displaced by EGTA. The amount of Ca bound to the cells increased as the extracellular Ca level was increased but was little affected by an excess of either Mg or Sr. Mare Ca bound to platelets when they were incubated at 25°C than at 37°C. This was because platelets lost their ability to bind Ca when they were incubated at 37°C in divalent cation-depleted plasma. This phenomenon was time-dependent and irreversible and was paralleled by a loss in the ability of the platelets to aggregate. These Ca binding sites would seem to be relevant to the aggregation process.

Divalent cation and lipid-protein interactions of biomembranes

1993 ◽  
Vol 13 (3) ◽  
pp. 143-157 ◽  
Author(s):  
F. Y. Yang ◽  
Y. G. Huang ◽  
Y. P. Tu
Keyword(s):  
Adenylate Cyclase ◽  
Atpase Activity ◽  
Enzymatic Activity ◽  
Divalent Cation ◽  
Protein Interactions ◽  
Physical State ◽  
Divalent Cations ◽  
Activity Change ◽  
Lipid Protein Interactions

Divalent cations play an important role in the functions of biomembranes. This review deals with three topics: (1) Mg2+-mediated change in physical state of phospholipid induces conformation and activity change of reconstituted mitochondrial H+-ATPase, (2) a proper transmembrane Ca2+ gradient is essential for the higher enzymatic activity of adenylate cyclase, and (3) role of transmembrane Ca2+ gradient in the modulation of reconstituted sarcoplasmic reticulm Ca2+-ATPase activity.

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 ON THE RECONSTITUTION OF THE CRYSTALLINE COMPONENTS OF THE SEA URCHIN FERTILIZATION MEMBRANE

1970 ◽  
Vol 45 (3) ◽  
pp. 606-614 ◽  
Author(s):  
Joseph Bryan
Keyword(s):  
Ionic Strength ◽  
Sea Urchin ◽  
Divalent Cations ◽  
Reducing Agents ◽  
Alkaline Ph ◽  
Mitotic Apparatus ◽  
Fertilization Membrane ◽  
Crystalline Component ◽  
Tubular Components

The characteristics of the reconstitution of a crystalline component of the sea urchin fertilization membrane are presented. The reassembly of large aggregates of cylindrical or tubular components is effected by the addition of calcium or other divalent cations. The reassembly requires a slightly alkaline pH and is little affected by increasing ionic strength. Reassembly is strongly inhibited by treatment with reducing agents such as dithiothreitol. The role of this protein in the formation of the fertilization membrane and its possible relation to the calcium-insoluble proteins of the mitotic apparatus are discussed.

scholarly journals Assembly of the sea urchin fertilization membrane: isolation of proteoliaisin, a calcium-dependent ovoperoxidase binding protein.

1985 ◽  
Vol 100 (3) ◽  
pp. 938-946 ◽  
Author(s):  
P J Weidman ◽  
E S Kay ◽  
B M Shapiro
Keyword(s):  
Sea Urchin ◽  
Divalent Cation ◽  
Divalent Cations ◽  
Dependent Manner ◽  
Cortical Granules ◽  
Binding Interaction ◽  
Membrane Assembly ◽  
Calcium Dependent ◽  
Structural Subunit ◽  
Fertilization Membrane

Fertilization of the sea urchin egg is accompanied by the assembly of an extracellular glycoprotein coat, the fertilization membrane. Assembly of the fertilization membrane involves exocytosis of egg cortical granules, divalent cation-mediated association of exudate proteins with the egg glycocalyx (the vitelline layer), and cross-linking of the assembled structure by ovoperoxidase, a fertilization membrane component derived from the cortical granules. We have identified and isolated a new protein, which we call proteoliaisin, that appears to be responsible for inserting ovoperoxidase into the fertilization membrane. Proteoliaisin is a 250,000-Mr protein that binds ovoperoxidase in a Ca2+-dependent manner, with half-maximal binding at 50 microM Ca2+. Other divalent cations are less effective (Ba2+, Mn2+, and Sr2+) or ineffective (Mg2+ and Cd2+) in mediating the binding interaction. Binding is optimal over the physiological pH range of fertilization membrane assembly (pH 5.5-7.5). Both proteoliaisin and ovoperoxidase are found in isolated, uncross-linked fertilization membranes. We have identified several macromolecular aggregates that are released from uncross-linked fertilization membranes after dilution into divalent cation-free buffer. One of these is an ovoperoxidase-proteoliaisin complex that is further disrupted only upon the addition of EGTA. These results suggest that a Ca2+-stabilized complex of ovoperoxidase and proteoliaisin forms one structural subunit of the fertilization membrane.

Role of the sea urchin egg receptor for sperm in gamete interactions

1995 ◽  
Vol 20 (1) ◽  
pp. 29-33 ◽  
Author(s):  
Kay Ohlendieck ◽  
William J. Lennarz
Keyword(s):  
Sea Urchin ◽  
Sea Urchin Egg ◽  
Gamete Interactions
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