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 STUDIES ON SULFHYDRYL GROUPS DURING CELL DIVISION OF SEA URCHIN EGG

1960 ◽  
Vol 8 (3) ◽  
pp. 609-615 ◽  
Author(s):  
Hikoichi Sakai
Keyword(s):  
Cell Division ◽  
Sea Urchin ◽  
Soluble Protein ◽  
Sulfhydryl Groups ◽  
Sh Groups ◽  
Sea Urchin Egg ◽  
Whole Egg ◽  
Egg Cortex

Sea urchin egg proteins extracted with KCl are mostly TCA-soluble and, conversely, those extracted with TCA are KCl-soluble. Both groups are water-insoluble and show fluctuations in—SH content during the division cycle. The fluctuation of the—SH groups of the KCl-soluble protein of the whole egg is due to a —SH⇌—S—S— interchange within the freely reacting groups and not within the sluggish and masked —SH groups of the protein. The —SH content of the KCl-soluble protein of the egg cortex also fluctuates in a similar way.

scholarly journals A method to quantitate maternal transcripts localized in sea urchin egg cortex by RT-qPCR with accurate normalization

2021 ◽  
Author(s):  
Konstantin Yakovlev ◽  
Yulia O. Kipryushina ◽  
Mariia A. Maiorova
Keyword(s):  
Sea Urchin ◽  
Reference Genes ◽  
Protein Localization ◽  
Rna Isolation ◽  
Suitable Reference Gene ◽  
Cortical Granules ◽  
Sea Urchin Eggs ◽  
Sea Urchin Egg ◽  
Maternal Transcripts ◽  
Egg Cortex

The sea urchin egg cortex is a peripheral region of eggs consisting of cell membrane and adjacent cytoplasm, which contains actin and tubulin cytoskeleton, cortical granules and some proteins required for early development. Method for isolation of cortices from sea urchin eggs and early embryos has been developed in 70s of 20th Century. Since that time this method has been reliable tool to study protein localization and cytoskeletal organization in cortex of unfertilized eggs and embryos during first cleavages. This study is an estimation of reliability of RT-qPCR to analyze levels of maternal transcripts that are localized in egg cortex. Firstly, we selected seven potential reference genes, 28S, Cycb , Ebr1 , GAPDH , Hmg1 , Smtnl1 and Ubb , which transcripts are maternally deposited in sea urchin eggs. The candidate reference genes were ranked by five different algorithms (BestKeeper, CV, ΔCt, geNorm and NormFinder) upon calculated level stability in both eggs and isolated cortices. Our results show that gene ranking differs in total RNA and mRNA samples, though Ubb is most suitable reference gene in both cases. To validate feasibility of comparative analysis of eggs and isolated egg cortices by RT-qPCR, we selected Daglb-2 as a gene of interest, which transcripts potentially localized in cortex, and found increased level of Daglb -2 in egg cortices. This suggests that proposed RNA isolation method with subsequent quantitative RT-qPCR analysis can be used to approve cortical association of transcripts in sea urchin eggs.

In vitro exocytosis in sea urchin eggs requires a synaptobrevin-related protein

1997 ◽  
Vol 110 (14) ◽  
pp. 1555-1561 ◽  
Author(s):  
J. Avery ◽  
A. Hodel ◽  
M. Whitaker
Keyword(s):  
Sea Urchin ◽  
Protein Sequence ◽  
In Vitro Model ◽  
Molecular Mechanisms ◽  
Related Protein ◽  
Sea Urchin Eggs ◽  
Sea Urchin Egg ◽  
Vitro Model ◽  
Egg Cortex

Sea urchin eggs provide an efficient in vitro model of exocytosis. We have identified proteins in sea urchin eggs that cross-react with antibodies to mammalian synaptobrevin, synaptotagmin, SNAP-25, syntaxin and rab3a. We show that these proteins are localized to the sea urchin egg cortex, using western blotting and immunocytochemistry. Tetanus toxin light chain cleaves the synaptobrevin-related protein in vitro and inhibits calcium-induced exocytosis. These data demonstrate a conservation between phyla of protein sequence and molecular mechanisms thought to facilitate exocytosis and show that the sea urchin egg provides a unique in vitro exocytotic model with which to study the conserved protein machinery of membrane fusion during secretion.

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.

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