Chapter IX Regulation of Cell Divisions in the Sea Urchin Embry

1982 ◽  
pp. 117-125 ◽  
Author(s):  
Elio Parisi ◽  
Silvana Filosa ◽  
Alberto Monroy
Keyword(s):  
Sea Urchin ◽  
Cell Divisions

The Effects of Spaceflight Conditions on Calcium-Dependent Secretion and Cytoskeletal Organization During Fertilization and Cell Divisions In the Sea Urchin Lytechinus Pictus

1999 ◽  
Vol 5 (S2) ◽  
pp. 1070-1071
Author(s):  
Heide Schatten ◽  
Amitabha Chakrabarti ◽  
Howard Levine ◽  
Mario Runco ◽  
Ken Anderson ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Research Facility ◽  
Cytoskeletal Organization ◽  
Lytechinus Pictus ◽  
Sea Urchin Eggs ◽  
Calcium Dependent ◽  
Kennedy Space Center ◽  
Cell Divisions ◽  
Kennedy Space ◽  
Calcium Loss

Calcium loss and muscle atrophy are two of the main metabolic changes experienced by astronauts and crew members during exposure to microgravity in space. To investigate the effects of spaceflight on calcium-dependent secretion and cytoskeletal formation in a less complex system we utilized sea urchin eggs and embryos which were fertilized and cultured under spaceflight conditions during the STS-77 shuttle mission. Sea urchin eggs were fertilized and cultured in the newly developed aquatic research facility (ARF) which allowed culture of eggs and embryos in microgravity and in a 1g centrifuge in space. This allowed analysis of the comparison of microgravity and 1g spaceflight treatments with samples cultured on ground. Eggs and embryos were maintained in Standard Container Assemblies (SCAs) with identical sets prepared for culture in microgravity, and at 1g in the middeck compartment of the shuttle Endeavor, as well as for ground observations at the Kennedy Space Center.

scholarly journals Intracellular pH of sea urchin eggs measured by the dimethyloxazolidinedione (DMO) method.

1981 ◽  
Vol 89 (2) ◽  
pp. 284-291 ◽  
Author(s):  
C H Johnson ◽  
D Epel
Keyword(s):  
Intracellular Ph ◽  
Sea Urchin ◽  
General Result ◽  
Strongylocentrotus Purpuratus ◽  
Lytechinus Pictus ◽  
Sea Urchin Eggs ◽  
Cell Divisions ◽  
Ph Microelectrodes

Intracellular pH (pH1) of sea urchin eggs and embryos was determined using DMO (5,5-dimethyl-2,4-oxazolidinedione). By this method, the pH1 of Lytechinus pictus eggs increased after fertilization from 6.86 to 7.27, and this higher pHi was maintained thereafter, as has been previously observed with pH microelectrodes. The same general result was obtained with the eggs of Strongylocentrotus purpuratus, in contrast to previous estimates of the pH of egg homogenates from this species, which had indicated a rise and then fall of pHi after fertilization. pHi did not significantly change during early cell divisions. Studies of treatments that alter pHi confirmed that ammonia alkalizes and acetate acidifies the cells. The regulation of pHi by embryos in the acidic seawater is impaired if sodium is absent, whereas unfertilized eggs can regulate pHi in acidic, sodium-free seawater.

Protein translation during early cell divisions of sea urchin embryos regulated at the level of polypeptide chain elongation and highly sensitive to natural polyamines

Zygote ◽  
2001 ◽  
Vol 9 (3) ◽  
pp. 229-236 ◽  
Author(s):  
Annabelle Monnier ◽  
Julia Morales ◽  
Patrick Cormier ◽  
Sandrine Boulben ◽  
Robert Bellé ◽  
...  
Keyword(s):  
Early Development ◽  
Sea Urchin ◽  
Protein Translation ◽  
Early Embryo ◽  
Chain Elongation ◽  
Time Interval ◽  
Short Time Interval ◽  
Cell Divisions ◽  
Highly Sensitive

Protein synthesis was analysed following fertilisation in sea urchin. Fluctuations in the accumulation of neo-synthesised proteins were observed during the first cell cycles. Accurate translation analyses were performed from lysates prepared from early embryos. The lysates readily translated endogenous pre-initiated mRNAs allowing the determination of elongation rates in the absence of re-initiation in vitro. The translation capacity of embryo lysates increased 18-fold from 0 to 90 min after fertilisation, reflecting the increase in the amount of pre-initiated mRNAs during early development. Kinetics analysis at a short time interval during the course of early development (240 min) showed an overall increase in the elongation rate (> 10-fold) which is regulated by pauses in synchrony with the cell divisions. Elongation activity in the lysates was highly sensitive to the natural polyamines, spermine (ID50 = 0.2 mM) and spermidine (ID50 = 1.8 mM), indicating high potential regulation by the intracellular level of polyamines in embryos. The regulation in the elongation changes associated with the early embryo cell divisions is discussed in the light of the physiological fluctuations in polyamine concentrations.

scholarly journals Evaluation of dimethoate toxicity on fertilization and on embryonic development of Paracentrotus lividus (Lamarck, 1816)

2020 ◽  
Vol 9 (4) ◽  
pp. 537-543
Author(s):  
Elena Maria Scalisi ◽  
Roberta Pecoraro ◽  
Antonio Salvaggio ◽  
Aurora Corsaro ◽  
Giuseppina Messina ◽  
...  
Keyword(s):  
Adverse Effects ◽  
Embryonic Development ◽  
Sea Urchin ◽  
Developmental Toxicity ◽  
Model Organism ◽  
Paracentrotus Lividus ◽  
Environmental Matrices ◽  
Cell Divisions ◽  
Fertilizing Ability ◽  
Pup Mortality

Abstract Organophosphates are a large class of chemicals with anticholinesterase action insecticides. Dimethoate belongs to the class of organophosphates and it is used for agriculture purpose. Its main toxicological role in animals and humans is the inhibition of the activity of acetylcholinesterase. Although it is not considered genotoxic, carcinogenic and teratogen, there is evidence of increased pup mortality in developmental neurotoxicity studies. Since there is scant published literature about developmental toxicity, we investigated the adverse effects of dimethoate on fertilization and embryonic development in sea urchin (Paracentrotus lividus), a model organism widely used to assess the toxicity of contaminants on environmental matrices; so pesticide residues can be released into the environment, and could affect the health of organisms, including humans. Different solution of dimethoate (4 × 10−3, 4 × 10−4, 4 × 10−5, 4 × 10−6 and 4 × 10−7 g/10 ml) have been tested on spermatozoa of P. lividus to evaluate the fertilizing ability of them when we added egg cells untreated. We demonstrated that dimethoate does not interfere with fertilizing ability of spermatozoa but egg cells fertilized by treated spermatozoa showed alterations in the segmentation planes as asymmetric and/or asynchronous cell divisions.

Stimulated Virus Production in Vinblastine and Cytochalasin-Induced Multinucleate Cells

1970 ◽  
Vol 28 ◽  
pp. 186-187
Author(s):  
Krishan Awtar
Keyword(s):  
Cell Division ◽  
Normal Cell ◽  
Virus Production ◽  
Multinucleate Cells ◽  
Daughter Cells ◽  
Cell Divisions ◽  
Nuclear Membranes ◽  
Division 2 ◽  
Vinblastine Sulfate

Exposure of cells to low sublethal but mitosis-arresting doses of vinblastine sulfate (Velban) results in the initial arrest of cells in mitosis followed by their subsequent return to an “interphase“-like stage. A large number of these cells reform their nuclear membranes and form large multimicronucleated cells, some containing as many as 25 or more micronuclei (1). Formation of large multinucleate cells is also caused by cytochalasin, by causing the fusion of daughter cells at the end of an otherwise .normal cell division (2). By the repetition of this process through subsequent cell divisions, large cells with 6 or more nuclei are formed.

Immunogold and immunoblot studies on a cell surface protein found in primary mesenchyme cells and in the cortical secretory vesicles of the sea urchin egg

1987 ◽  
Vol 45 ◽  
pp. 832-833
Author(s):  
G.L. Decker ◽  
M.C. Valdizan
Keyword(s):  
Cell Surface ◽  
Sea Urchin ◽  
Surface Protein ◽  
Egg Cell ◽  
Secretory Vesicles ◽  
Cell Surface Protein ◽  
Surface Complexes ◽  
Mesenchyme Cells ◽  
Lowicryl K4m ◽  
Primary Mesenchyme Cells

A monoclonal antibody designated MAb 1223 has been used to show that primary mesenchyme cells of the sea urchin embryo express a 130-kDa cell surface protein that may be directly involved in Ca2+ uptake required for growth of skeletal spicules. Other studies from this laboratory have shown that the 1223 antigen, although in relatively low abundance, is also expressed on the cell surfaces of unfertilized eggs and on the majority of blastomeres formed prior to differentiation of the primary mesenchyme cells.We have studied the distribution of 1223 antigen in S. purpuratus eggs and embryos and in isolated egg cell surface complexes that contain the cortical secretory vesicles. Specimens were fixed in 1.0% paraformaldehyde and 1.0% glutaraldehyde and embedded in Lowicryl K4M as previously reported. Colloidal gold (8nm diameter) was prepared by the method of Mulpfordt.

The extracellular matrix of echinoderm and amphibian eggs: Visualization in quick-frozen, deep-etched, and rotary-shadowed specimens

1990 ◽  
Vol 48 (3) ◽  
pp. 60-61
Author(s):  
Barry Bonnell ◽  
Carolyn Larabell ◽  
Douglas Chandler
Keyword(s):  
Extracellular Matrix ◽  
Plasma Membrane ◽  
Sea Urchin ◽  
Crystalline Structure ◽  
Cortical Granule ◽  
Two Dimensional ◽  
Small Peptides ◽  
Deep Etching ◽  
Quick Freezing ◽  
Acrosomal Reaction

Eggs of many species including those of echinoderms, amphibians and mammals exhibit an extensive extracellular matrix (ECM) that is important both in the reception of sperm and in providing a block to polyspermy after fertilization.In sea urchin eggs there are two distinctive coats, the vitelline layer which contains glycoprotein sperm receptors and the jelly layer that contains fucose sulfate glycoconjugates which trigger the acrosomal reaction and small peptides which act as chemoattractants for sperm. The vitelline layer (VL), as visualized by quick-freezing, deep-etching, and rotary-shadowing (QFDE-RS), is a fishnet-like structure, anchored to the plasma membrane by short posts. Orbiting above the VL are horizontal filaments which are thought to anchor the thicker jelly layer to the egg. Upon fertilization, the VL elevates and is transformed by cortical granule secretions into the fertilization envelope (FE). The rounded casts of microvilli in the VL are transformed into angular peaks and the envelope becomes coated inside and out with sheets of paracrystalline protein having a quasi-two dimensional crystalline structure.

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