Induction of fertilization membrane by ionophore A23187 in sea urchin egg Paracentrotus lividus

1974 ◽  
Vol 89 (2) ◽  
pp. 425-426 ◽  
Author(s):  
R LALLIER
Keyword(s):  
Sea Urchin ◽  
Paracentrotus Lividus ◽  
Ionophore A23187 ◽  
Sea Urchin Egg ◽  
Fertilization Membrane

Isolated Plasma Membranes of Sea Urchin Eggs

1971 ◽  
Vol 29 ◽  
pp. 534-535
Author(s):  
S. Inoue ◽  
E. C. Preddie ◽  
P. Guerrier
Keyword(s):  
Electron Microscope ◽  
Sea Urchin ◽  
Plasma Membranes ◽  
Membrane System ◽  
Vitelline Membrane ◽  
Thin Sections ◽  
Sea Urchin Eggs ◽  
Sea Urchin Egg ◽  
Discontinuous Sucrose Gradient ◽  
Fertilization Membrane

From electron microscope studies of thin sections the sea urchin egg is known to be surrounded by the peripheral membrane system which is made up of the outer coat (vitelline membrane), which elevates from an egg surface after fertilization and becomes a part of the fertilization membrane, and the plasma membrane. In these experiments an effort has been made to isolate plasma membranes of sea urchin eggs and these isolated membranes were observed in the electron microscope.The vitelline membrane of the eggs from the sea urchin Strongylocentrotus purpuratus was at first digested away by the treatment with 0.02% trypsin in 0.01 M Tris-HCl buffer (pH 8.0) for 5 minutes at 28°C. The plasma membranes were then isolated according to the method of Song et al. which was used for the isolation of rat liver plasma membranes. The vitelline membrane-free eggs were gently homogenized in 10-3 M NaHC03 (pH 7.5) and freed membranes were collected by centrifugation over a discontinuous sucrose gradient preparation.

scholarly journals Structural organization of actin in the sea urchin egg cortex: microvillar elongation in the absence of actin filament bundle formation

1982 ◽  
Vol 93 (1) ◽  
pp. 24-32 ◽  
Author(s):  
DA Begg ◽  
LI Rebhun ◽  
H Hyatt
Keyword(s):  
Sea Urchin ◽  
Actin Filament ◽  
Actin Filaments ◽  
Calcium Ionophore ◽  
Ionophore A23187 ◽  
Acid Activation ◽  
Cytoplasmic Ph ◽  
Sea Urchin Egg ◽  
Filament Bundles ◽  
Filament Bundle

We have investigated the relationship between the formation of actin filament bundles and the elongation of microvilli (MV) after fertilization in sea urchin eggs. In a previous study (1979, J Cell Biol. 83:241-248) we demonstrated that increased pH induced the formation of actin filaments in isolated sea urchin egg cortices with the concomitant elongation of MV. On the basis of these results we suggested that increased cytoplasmic pH after fertilization causes a reorganization of cortical actin, which in turn provides the force for MV elongation. To test this hypothesis, we compared the morphology of microvilli in eggs activated with and without the release of fertilization acid. Activation of eggs in normal sea water with the calcium ionophore A23187 causes the release of fertilization acid and the elongation of MV containing core bundles of actin filaments. Eggs activated with A23187 in NA(+)-free water do not undergo normal fertilization acid release but develop elongated, flaccid MV. These MV contain an irregular network of actin filaments rather than the parallel bundles of filaments found in normal MV. The addition of 40 mM NaCl to these eggs results in the release of H(+) and the concomitant conversion of flaccid MV to erect MV containing typical core bundles of actin filaments. Identical results are obtained when 10 mM NH(4)Cl is substituted for NaCl. The induction of cytoplasmic alkalinization in unactivated eggs with NH(4)Cl does not cause either MV elongation or the formation of actin filament bundles . These results suggest that: (a) the elongation of MV is stimulated by a rise in intracellular free Ca(++) concentration; (b) actin filament bundle formation is triggered by an increase in cytoplasmic pH; and (c) the formation of actin filament bundles is not necessary for MV elongation but is required to provide rigid support for MV.

Mechanism of Formation of the Fertilization Membrane in the Sea Urchin Egg

Nature ◽  
1944 ◽  
Vol 153 (3880) ◽  
pp. 313-314 ◽  
Author(s):  
JOHN RUNNSTRÖM ◽  
LUDWIK MONNÉ ◽  
ELSA WICKLUND
Keyword(s):  
Sea Urchin ◽  
Mechanism Of Formation ◽  
Sea Urchin Egg ◽  
Fertilization Membrane

scholarly journals Electrophoretic movement of fertilized sea-urchin eggs

1982 ◽  
Vol 55 (1) ◽  
pp. 105-113
Author(s):  
N. Oshima
Keyword(s):  
Electric Field ◽  
Surface Charge ◽  
Electrophoretic Mobility ◽  
Sea Urchin ◽  
Egg Cell ◽  
Migration Speed ◽  
Protamine Sulphate ◽  
Sea Urchin Egg ◽  
Fertilization Membrane ◽  
Whole Egg

The eccentric shift of the sea-urchin egg within the fertilization membrane under an electric field was analysed by measuring the electrophoretic mobility of the isolated fertilization membrane and that of the egg deprived of the fertilization membrane. In addition, the migration speed of the egg proper was measured within the fertilization membrane under the conditions that: either (1) the movement of the whole egg was arrested, or (2) protamine sulphate was adsorbed on the fertilization membrane to reduce its mobility. The results led to conclusions that: (1) both the fertilization membrane and the egg cell with the hyaline layer are negatively charged; (2) movement of the normal fertilized eggs is due mainly to the surface charge of the fertilization membrane; and (3) the eccentric position of the egg within the fertilization membrane is due to migration of the egg proper, which is independent of the movement of the whole egg.

scholarly journals The Inorganic Constituents of the Sea-Urchin Egg

1953 ◽  
Vol 30 (4) ◽  
pp. 534-544
Author(s):  
LORD ROTHSCHILD ◽  
H. BARNES
Keyword(s):  
Sea Urchin ◽  
Total Phosphorus ◽  
Phosphorus Content ◽  
Sea Water ◽  
Paracentrotus Lividus ◽  
Dry Weight ◽  
Chemical Methods ◽  
Sea Urchin Egg ◽  
Soluble Phosphorus ◽  
Inorganic Constituents

1. The principal inorganic constituents of the unfertilized egg of Paracentrotus lividus have been analysed by chemical methods. The results of the analyses, in millimoles per kg. of water in the eggs (dry weight of eggs, 24%; density, 1.09), were: The figures in brackets are the concentrations of the same substances in Roscoff sea water, chlorinity 19.37‰ in the same units. 2. The total phosphorus content of the eggs was about 2 mg./ml. eggs, somewhat over half of this being acid-soluble phosphorus.

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