The Surface of the Sea-urchin Egg

1958 ◽  
Vol s3-99 (45) ◽  
pp. 1-3
Author(s):  
LORD ROTHSCHILD
Keyword(s):  
Electron Microscope ◽  
Potassium Permanganate ◽  
Sea Urchin ◽  
Outer Electron ◽  
Transparent Layer ◽  
Sea Urchin Egg

Unfertilized eggs of the sea-urchin Echinus esculentus were fixed in potassium permanganate, sectioned, and examined under the electron microscope. A membrane consisting of an outer electron-opaque layer 84 Å wide, an electron-transparent layer 67 Å wide, and an inner electron-opaque layer 66 A wide was observed at the egg surface. No other membrane or electron-opaque layer could be found anywhere within 4µ of the egg surface.

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.

Scanning electron microscope studies of the surface of the sea urchin egg

PROTOPLASMA ◽  
1976 ◽  
Vol 87 (4) ◽  
pp. 281-290 ◽  
Author(s):  
Berndt E. Hagström ◽  
Sunniva Lönning
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Sea Urchin ◽  
Sea Urchin Egg ◽  
Scanning Electron

scholarly journals Different Ca2+-releasing abilities of sperm extracts compared with tissue extracts and phospholipase C isoforms in sea urchin egg homogenate and mouse eggs

2000 ◽  
Vol 346 (3) ◽  
pp. 743-749 ◽  
Author(s):  
Keith T. JONES ◽  
Miho MATSUDA ◽  
John PARRINGTON ◽  
Matilda KATAN ◽  
Karl SWANN
Keyword(s):  
Phospholipase C ◽  
Sea Urchin ◽  
Tissue Extracts ◽  
Sea Urchin Egg ◽  
Boar Sperm ◽  
Specific Activities ◽  
Mammalian Eggs ◽  
Mouse Eggs

A soluble phospholipase C (PLC) from boar sperm generates InsP3 and hence causes Ca2+ release when added to sea urchin egg homogenate. This PLC activity is associated with the ability of sperm extracts to cause Ca2+ oscillations in mammalian eggs following fractionation. A sperm PLC may, therefore, be responsible for causing the observed Ca2+ oscillations at fertilization. In the present study we have further characterized this boar sperm PLC activity using sea urchin egg homogenate. Consistent with a sperm PLC acting on egg PtdIns(4,5)P2, the ability of sperm extracts to release Ca2+ was blocked by preincubation with the PLC inhibitor U73122 or by the addition of neomycin to the homogenate. The Ca2+-releasing activity was also detectable in sperm from other species and in whole testis extracts. However, activity was not observed in extracts from other tissues. Moreover recombinant PLCβ1, -γ1, -γ2, -∆1, all of which had higher specific activities than boar sperm extracts, were not able to release Ca2+ in the sea urchin egg homogenate. In addition these PLCs were not able to cause Ca2+ oscillations following microinjection into mouse eggs. These results imply that the sperm PLC possesses distinct properties that allow it to hydrolyse PtdIns(4,5)P2 in eggs.

ACID-SOLUBLE NUCLEOTIDES IN THE SEA URCHIN EGG

Embryologia ◽  
1966 ◽  
Vol 9 (3) ◽  
pp. 170-183 ◽  
Author(s):  
TOMIO YANAGISAWA ◽  
NAOHIDE ISONO
Keyword(s):  
Sea Urchin ◽  
Sea Urchin Egg
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