scholarly journals ACTION OF COLCEMID IN SEA URCHIN EGGS

1967 ◽  
Vol 34 (2) ◽  
pp. 483-488 ◽  
Author(s):  
Arthur M. Zimmerman ◽  
Selma Zimmerman
Keyword(s):  
Cell Division ◽  
Dna Synthesis ◽  
Sea Urchin ◽  
Mitotic Spindle ◽  
Methyl Derivative ◽  
Arbacia Punctulata ◽  
Sea Urchin Eggs ◽  
Sea Urchin Egg ◽  
Silver Grains

The effects of Colcemid, the deacetyl-N-methyl derivative of colchicine, on the eggs of Arbacia punctulata were investigated. Colcemid in concentrations of 2.7 x 10-5 M or greater blocks syngamy (the fusion of the pronuclei) in these eggs. Although a tenfold decrease in concentration of Colcemid usually permits the pronuclei to fuse, the subsequent division is blocked. In the sea urchin egg, the duration of presyngamy is about 15 min during which time there is no DNA synthesis. However, DNA synthesis is recorded in Colcemid-blocked cells prior to syngamy. Radioautographs of Colcemid-blocked cells which were immersed into thymidine-3H exhibited silver grains above each of the pronuclei. The action of Colcemid on Arbacia eggs is reversible. Nevertheless, exposures to 2.7 x 10-5 M Colcemid for only 3 min, initiated 5 min after insemination, caused delays of 70 min in subsequent division. In general, cells are more sensitive to Colcemid prior to the time when the mitotic spindle is being assembled than at presyngamy stages. The results are discussed in terms of Colcemid action on pronuclear fusion and cell division.

scholarly journals STUDIES ON SULFHYDRYL GROUPS DURING CELL DIVISION OF SEA URCHIN EGG

1960 ◽  
Vol 8 (3) ◽  
pp. 603-607 ◽  
Author(s):  
Hikoichi Sakai
Keyword(s):  
Cell Division ◽  
Sea Urchin ◽  
Sulfhydryl Groups ◽  
Cell Stage ◽  
Sea Urchin Eggs ◽  
Maximum Value ◽  
Sea Urchin Egg ◽  
Egg Cortex

Masses of cortices of both unfertilized and fertilized sea urchin eggs can be isolated by crushing eggs in hypotonic MaCl2 (0.1 M) solution. The amount of cortical material in terms of protein-N increases steadily after fertilization until the monaster stage and thereafter remains almost constant until well into the two-cell stage. The amount of bound—SH per protein-N of the egg cortex also increases after fertilization, reaches a maximum value at the amphiaster stage and thereafter decreases rapidly as the cleavage of the cell proceeds.

scholarly journals THE EFFECT OF PENICILLIN ON EGGS OF THE SEA URCHIN, ARBACIA PUNCTULATA

1945 ◽  
Vol 28 (5) ◽  
pp. 405-413 ◽  
Author(s):  
Richard J. Henry ◽  
Maryon D. Henry
Keyword(s):  
Oxygen Consumption ◽  
Cell Division ◽  
Sea Urchin ◽  
Inhibitory Action ◽  
Initial Concentration ◽  
Arbacia Punctulata ◽  
Sea Urchin Egg

1. Penicillin in the range of concentration from 250 U/ml. to approximately 2650 U/ml. inhibits the rate of cell division of the fertilized sea urchin egg from 0 to 100 per cent. 2. Penicillin in the same range of concentrations has no effect on the oxygen consumption of the unfertilized or the fertilized eggs. 3. Penicillin is bound by some component of the sea urchin egg in amounts sufficiently large to lower the initial concentration, this binding apparently not being related to the inhibitory action.

Effect of wortmannin, an inhibitor of phosphatidylinositol 3-kinase, on the first mitotic divisions of the fertilized sea urchin egg

1998 ◽  
Vol 111 (17) ◽  
pp. 2507-2518 ◽  
Author(s):  
C. De Nadai ◽  
P. Huitorel ◽  
S. Chiri ◽  
B. Ciapa
Keyword(s):  
Sea Urchin ◽  
Mitotic Spindle ◽  
Second Messengers ◽  
Cellular Systems ◽  
Phosphatidylinositol 3 Kinase ◽  
Sea Urchin Eggs ◽  
Cellular Processes ◽  
Nuclear Envelope Breakdown ◽  
Sea Urchin Egg ◽  
Messenger System

We have reported earlier that the polyphosphoinositide messenger system may control mitosis in sea urchin eggs. Besides phospholipase C activation and its second messengers, phosphatidylinositol (PI) 3-kinase has been proposed to affect a wide variety of cellular processes in other cellular systems. Therefore, we have investigated whether PI 3-kinase could play a role in regulating the sea urchin early embryonic development. Our data presented here suggest that PI 3-kinase is present in sea urchin eggs. We found that wortmannin, an inhibitor of PI 3-kinase, led to arrest of the cell cycle. Chromosome condensation, nuclear envelope breakdown, microtubular aster polymerization, protein and DNA synthesis were not affected when fertilization was performed in the presence of the drug. However, maturation-promoting factor (MPF) activation was inhibited and centrosome duplication was perturbed preventing the formation of a bipolar mitotic spindle in wortmannin treated eggs. We discuss how PI 3-kinase might be involved in the cascade of events leading to the first mitotic divisions of the fertilized sea urchin egg.

scholarly journals Nicotinic acid-adenine dinucleotide phosphate mobilizes Ca2+ from a thapsigargin-insensitive pool

1996 ◽  
Vol 315 (3) ◽  
pp. 721-725 ◽  
Author(s):  
Armando A. GENAZZANI ◽  
Antony GALIONE
Keyword(s):  
Nicotinic Acid ◽  
Sea Urchin ◽  
Cross Talk ◽  
Inositol Trisphosphate ◽  
Sea Urchin Eggs ◽  
Bivalent Cations ◽  
Sea Urchin Egg ◽  
Different Characteristics ◽  
Degree Of Overlap

Nicotinic acid–adenine dinucleotide phosphate (NAADP) is a novel intracellular Ca2+ releasing agent recently described in sea-urchin eggs and egg homogenates. Ca2+ release by NAADP is independent of that induced by either inositol trisphosphate (InsP3) or cyclic adenosine dinucleotide phosphate (cADPR). We now report that in sea urchin egg homogenates, NAADP releases Ca2+ from a Ca2+ pool that is distinct from those that are sensitive to InsP3 and cADPR. This organelle has distinct Ca2+ uptake characteristics: it is insensitive to thapsigargin and cyclopiazoic acid, but maintenance of the pool shows some requirement for ATP. Although the different Ca2+ pools have different characteristics, there appears to be some degree of overlap or cross-talk between the NAADP- and cADPR/InsP3-sensitive Ca2+ pools. Ca2+-induced Ca2+ release is unlikely to account for the apparent overlap between stores, since NAADP-induced Ca2+ release, in contrast with that stimulated by cADPR, is not potentiated by bivalent cations.

scholarly journals A Quantitative Description of Protoplasmic Movement During Cleavage in the Sea-Urchin Egg

1958 ◽  
Vol 35 (2) ◽  
pp. 407-424
Author(s):  
Y. HIRAMOTO
Keyword(s):  
Cell Division ◽  
Sea Urchin ◽  
Quantitative Description ◽  
Motive Force ◽  
Mitotic Apparatus ◽  
Band Theory ◽  
Cytoplasmic Granules ◽  
Carbon Particles ◽  
Sea Urchin Egg ◽  
Protoplasmic Movement

1. Protoplasmic movements during cleavage in the eggs of the heart-urchin Clypeaster japonicus have been followed by tracing the movements of cytoplasmic granules and of carbon particles adhering to the surface. 2. These movements are quantitatively described in normal eggs and in eggs whose mitotic apparatus has been destroyed by colchicine. 3. The results obtained are qualitatively similar to those obtained by Spek and by Dan and his collaborators. 4. Endoplasmic movement and changes in the length and shape of the astral rays are readily explained by the contracting-ring (band) theory. 5. The location of the motive force of cell division is discussed.

Ryanodine Activates Sea Urchin Eggs. (sea urchin egg/activation/ryanodine/inositol phosphate/heparin)

1992 ◽  
Vol 34 (1) ◽  
pp. 37-42 ◽  
Author(s):  
C. Sardet ◽  
I. Gillot ◽  
A. Ruscher ◽  
P. Payan ◽  
J.-P. Girard ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Inositol Phosphate ◽  
Egg Activation ◽  
Sea Urchin Eggs ◽  
Sea Urchin Egg

The Respiratory and Glycolytic Enzymes of Sea-Urchin Eggs

1954 ◽  
Vol 31 (2) ◽  
pp. 208-217
Author(s):  
MARTYNAS YČAS
Keyword(s):  
Cytochrome C ◽  
Sea Urchin ◽  
Strongylocentrotus Purpuratus ◽  
Lactic Dehydrogenase ◽  
Glycolytic Pathway ◽  
Endogenous Respiration ◽  
Centrifugal Field ◽  
Lytechinus Pictus ◽  
Sea Urchin Eggs ◽  
Sea Urchin Egg

1. Activity corresponding to phosphoglucomutase, phosphohexoisomerase, aldolase, triosephosphate dehydrogenase, enolase and lactic dehydrogenase has been demonstrated in homogenates prepared from unfertilized sea-urchin eggs (Strongylocentrotus purpuratus and Lytechinus pictus). 2. The presence of cytochromes a and b1 has been confirmed. These cytochromes sediment in a relatively low centrifugal field. 3. No cytochrome c could be demonstrated, although cytochrome c is both reduced and oxidized by homogenates, and addition of cytochrome c increases the endogenous respiration and oxidation of succinate. 4. These results support the view that the usual glycolytic pathway operates in the sea-urchin egg and is the principal route of oxidation of carbohydrate.

Sign in / Sign up

Export Citation Format

Share Document