scholarly journals Organization of the sea urchin egg endoplasmic reticulum and its reorganization at fertilization.

1991 ◽  
Vol 114 (5) ◽  
pp. 929-940 ◽  
Author(s):  
M Terasaki ◽  
L A Jaffe
Keyword(s):  
Sea Urchin ◽  
Time Lapse ◽  
Sperm Nucleus ◽  
Temporal Organization ◽  
Calcium Wave ◽  
Zygote Nucleus ◽  
Lytechinus Pictus ◽  
Sea Urchin Egg ◽  
A Cell ◽  
Sperm Aster

The ER of eggs of the sea urchin Lytechinus pictus was stained by microinjecting a saturated solution of the fluorescent dicarbocyanine DiIC18(3) (DiI) in soybean oil; the dye spread from the oil drop into ER membranes throughout the egg but not into other organelles. Confocal microscopy revealed large cisternae extending throughout the interior of the egg and a tubular membrane network at the cortex. Since diffusion of DiI is confined to continuous bilayers, the spread of the dye supports the concept that the ER is a cell-wide, interconnected compartment. In time lapse observations, the internal cisternae were seen to be in continuous motion, while the cortical ER was stationary. After fertilization, the internal ER appeared to become more finely divided, beginning as a wave apparently coincident with the calcium wave and becoming most marked by 2-3 min. By 5-8 min the ER returned to an organization similar to that of the unfertilized egg. The cortical network also changed at fertilization; it became disrupted and eventually recovered. DiI labeling allowed continuous observations of the ER during pronuclear migration and mitosis. DiI-stained membranes accumulated in the region of the microtubule array surrounding the sperm nucleus and centriole (the sperm aster) as it migrated to the center of the egg; this accumulation persisted near the centrosomes and zygote nucleus throughout pronuclear fusion and the first two mitotic cycles. We have used a new method to observe the spatial and temporal organization of the ER in a living cell, and we have demonstrated a striking reorganization of the ER at fertilization.

scholarly journals THE FINE STRUCTURE OF PRONUCLEAR DEVELOPMENT AND FUSION IN THE SEA URCHIN, ARBACIA PUNCTULATA

1968 ◽  
Vol 39 (2) ◽  
pp. 339-368 ◽  
Author(s):  
Frank J. Longo ◽  
Everett Anderson
Keyword(s):  
Nuclear Envelope ◽  
Sea Urchin ◽  
Plasma Membranes ◽  
Light And Electron Microscopy ◽  
Sperm Nucleus ◽  
Sperm Chromatin ◽  
Zygote Nucleus ◽  
Arbacia Punctulata ◽  
Male Pronucleus ◽  
Sperm Aster

Fertilization events following coalescence of the gamete plasma membranes and culminating in the formation of the zygote nucleus were investigated by light and electron microscopy in the sea urchin, Arbacia punctulata. Shortly after the spermatozoon passes through the fertilization cone, it rotates approximately 180° and comes to rest lateral to its point of entrance. Concomitantly, the nonperforated nuclear envelope of the sperm nucleus undergoes degeneration followed by dispersal of the sperm chromatin and development of the pronuclear envelope. During this reorganization of the sperm nucleus, the sperm aster is formed. The latter is composed of ooplasmic lamellar structures and fasciles of microtubules. The male pronucleus, sperm mitochondrion, and flagellum accompany the sperm aster during its migration. As the pronuclei encounter one another, the surface of the female pronucleus proximal to the advancing male pronucleus becomes highly convoluted. Subsequently, the formation of the zygote nucleus commences with the fusion of the outer and the inner membranes of the pronuclear envelopes, thereby producing a small internuclear bridge and one continuous, perforated zygote nuclear envelope.

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.

Psammechinus miliaris egg homogenate as a model to investigate Ca2+-release mechanisms

1999 ◽  
Vol 79 (2) ◽  
pp. 323-326 ◽  
Author(s):  
Armando A. Genazzani ◽  
Heather L. Wilson ◽  
Antony Galione
Keyword(s):  
Sea Urchin ◽  
Calcium Release ◽  
Lytechinus Pictus ◽  
Release Mechanisms ◽  
Psammechinus Miliaris ◽  
Sea Urchin Egg ◽  
Cyclic Adp Ribose ◽  
The Usa ◽  
Release Model ◽  
Convenient Model

The sea urchin egg has proved a reliable and robust system for measuring intracellular calcium release in response to three independent mechanisms: inositol 1,4,5 trisphosphate, cyclic ADP-ribose and the recently identified molecule, nicotinic acid adenine dinucleotide phosphate (NAADP). These calcium release mechanisms have been studied in homogenates of Lytechinus pictus and Spongylocentrotus purpuratus, which are two sea urchin species located off the west coast of the USA. A new calcium-release model from a species of sea urchin present off the coasts of Britain, Psammechinus miliaris is characterized and described. Although the Ca2+-release characteristics in this species do not differ from those of the other two sea urchin species, it may provide a more economical and convenient model for European scientists.

Ectoderm nuclei from sea urchin embryos contain a Spec-DNA binding protein similar to the vertebrate transcription factor USF

Development ◽  
1990 ◽  
Vol 110 (1) ◽  
pp. 259-272 ◽  
Author(s):  
C.R. Tomlinson ◽  
M.T. Kozlowski ◽  
W.H. Klein
Keyword(s):  
Transcription Factor ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Dna Interaction ◽  
Initiation Site ◽  
Upstream Stimulatory Factor ◽  
Transcriptional Initiation ◽  
Lytechinus Pictus ◽  
Conserved Sequence ◽  
A Cell

The Spec gene family of Stronglyocentrotus purpuratus is expressed exclusively in aboral ectoderm cells during embryogenesis. To investigate the regulation of Spec gene activity, the region around the Spec1 transcriptional initiation site was analyzed for sites of protein-DNA interaction. One high-affinity site bound a factor termed SpF1 within the Spec1 5′ untranslated leader region at position +39 to +60. The core sequence recognized by SpF1, CACGTG, is the same as that of the upstream stimulatory factor (USF), a widely occurring vertebrate transcription factor containing a myc-HLH motif. A comparison of USF- and SpF1-binding activities suggested that SpF1 was a sea urchin version of USF. SpF1 activity was detectable only in ectoderm cells of the embryo, implying that it has a role as a cell type-specific transcription factor. SpF1-binding sites were also found upstream of the Spec2a and Spec2c genes in the same conserved sequence block as Spec1. Extracts from Lytechinus pictus embryos showed an SpF1-like activity, suggesting that SpF1 is conserved in sea urchins. Surprisingly, changes in the Spec1, Spec2a, or Spec2c genes that removed or modified the SpF1-binding site had no effect on expression when reporter gene fusions containing these mutations were injected into sea urchin eggs and analyzed for expression during embryogenesis. We propose that, while SpF1 may not be essential for expression of the exogenously introduced reporter genes, it may be required for proper regulation of the endogenous Spec genes.

scholarly journals Hierarchies of protein cross-linking in the extracellular matrix: involvement of an egg surface transglutaminase in early stages of fertilization envelope assembly.

1988 ◽  
Vol 107 (6) ◽  
pp. 2447-2454 ◽  
Author(s):  
D E Battaglia ◽  
B M Shapiro
Keyword(s):  
Cell Surface ◽  
Sea Urchin ◽  
Physiological Function ◽  
Strongylocentrotus Purpuratus ◽  
Cross Linking ◽  
Early Step ◽  
Transglutaminase Activity ◽  
Sea Urchin Egg ◽  
A Cell ◽  
Secretory Products

The involvement of transglutaminase activity in fertilization envelope (FE) formation was investigated using eggs from the sea urchin, Strongylocentrotus purpuratus. Eggs fertilized in the presence of the transglutaminase inhibitors, putrescine and cadaverine, had disorganized and expanded FEs with inhibition of the characteristic I-T transition. The permeability of the FE was increased by these agents, as revealed by the loss of proteins from the perivitelline space and the appearance of ovoperoxidase activity in supernates from putrescine-treated eggs. [3H]putrescine was incorporated into the FE during fertilization in a reaction catalyzed by an egg surface transglutaminase that could also use dimethylcasein as a substrate in vitelline layer-denuded eggs. Egg secretory products alone had no transglutaminase activity. The cell surface transglutaminase activity was transient and maximal within 4 min of activation. The enzyme was Ca2+ dependent and was inhibited by Zn2+. We conclude that sea urchin egg surface transglutaminase catalyzes an early step in a hierarchy of cross-linking events during FE assembly, one that occurs before ovoperoxidase-mediated dityrosine formation (Foerder, C. A., and B. M. Shapiro. 1977. Proc. Natl. Acad. Sci. USA. 74:4214-4218). Thus it provides a graphic example of the physiological function of a cell surface transglutaminase.

scholarly journals Demonstration of calcium uptake and release by sea urchin egg cortical endoplasmic reticulum.

1991 ◽  
Vol 115 (4) ◽  
pp. 1031-1037 ◽  
Author(s):  
M Terasaki ◽  
C Sardet
Keyword(s):  
Sea Urchin ◽  
Calcium Release ◽  
Time Lapse ◽  
Fluorescence Signal ◽  
Calcium Sequestration ◽  
Calcium Indicator ◽  
Sea Urchin Egg ◽  
Isolated Cortex ◽  
A Site ◽  
Indicator Dye

The calcium indicator dye fluo-3/AM was loaded into the ER of isolated cortices of unfertilized eggs of the sea urchin Arbacia punctulata. Development of the fluorescent signal took from 8 to 40 min and usually required 1 mM ATP. The signal decreased to a minimum level within 30 s after perfusion with 1 microM InsP3 and increased within 5 min when InsP3 was replaced with 1 mM ATP. Also, the fluorescence signal was lowered rapidly by perfusion with 10 microM A23187 or 10 microM ionomycin. These findings demonstrate that the cortical ER is a site of ATP-dependent calcium sequestration and InsP3-induced calcium release. A light-induced wave of calcium release, traveling between 0.7 and 2.8 microns/s (average speed 1.4 microns/s, N = 8), was sometimes observed during time lapse recordings; it may therefore be possible to use the isolated cortex preparation to investigate the postfertilization calcium wave.

scholarly journals The part played by inositol trisphosphate and calcium in the propagation of the fertilization wave in sea urchin eggs.

1986 ◽  
Vol 103 (6) ◽  
pp. 2333-2342 ◽  
Author(s):  
K Swann ◽  
M Whitaker
Keyword(s):  
Sea Urchin ◽  
Calcium Ions ◽  
Calcium Concentration ◽  
Calcium Release ◽  
Inositol Trisphosphate ◽  
Lytechinus Pictus ◽  
Sea Urchin Egg ◽  
Sperm Entry ◽  
Fertilization Membrane

Sea urchin egg activation at fertilization is progressive, beginning at the point of sperm entry and moving across the egg with a velocity of 5 microns/s. This activation wave (Kacser, H., 1955, J. Exp. Biol., 32:451-467) has been suggested to be the result of a progressive release of calcium from a store within the egg cytoplasm (Jaffe, L. F., 1983, Dev. Biol., 99:265-276). The progressive release of calcium may be due to the production of inositol trisphosphate (InsP3), a second messenger. We show here that a wave of calcium release crosses the Lytechinus pictus egg; the peak of the wave travels with a velocity of 5 microns/s; microinjection of InsP3 causes the release of calcium within the egg; calcium release (as judged by fertilization envelope elevation) is abolished by prior injection of the calcium chelator EGTA; neomycin, an inhibitor of InsP3 production, does not prevent the release of calcium in response to InsP3 but does abolish the wave of calcium release; the egg cytoplasm rapidly buffers microinjected calcium; the calcium concentration required to cause fertilization membrane elevation when microinjected is very similar to that required to stimulate the production of InsP3 in vitro; and the progressive fertilization membrane elevation seen after microinjection of calcium buffers appears to be due to diffusion of the buffer across the egg cytoplasm rather than to the induction of the activation wave. We conclude that InsP3 diffuses through the egg cytoplasm much more readily than calcium ions and that calcium-stimulated production of InsP3 and InsP3-induced calcium release from an internal store can account for the progressive release of calcium at fertilization.

The Thickness of the Cortex of the Sea-Urchin Egg and the Problem of the Vitelline Membrane

1956 ◽  
Vol s3-97 (37) ◽  
pp. 109-121
Author(s):  
J. M. MITCHISON
Keyword(s):  
Sea Urchin ◽  
Granular Layer ◽  
Paracentrotus Lividus ◽  
Vitelline Membrane ◽  
Cortical Granules ◽  
A Value ◽  
Sea Urchin Egg ◽  
Hyaline Zone ◽  
Sperm Aster ◽  
Arbacia Lixula

The gelated cortex of a sea-urchin egg can be seen as a granular layer at the edge of the hyaline zone in a centrifuged egg. Measurements were made of the thickness of this layer in the eggs of Paracentrotus lividus and Arbacia lixula at various stages of development from the unfertilized egg to the first cleavage. The thickness was roughly 2 µ in living eggs, and 1.15-1.35 µ in sections of fixed eggs. There were no appreciable changes in the thickness up to the first cleavage, and it is concluded that a value of 1.5 µ can be taken as an approximate figure for all stages. The cortex is usually invisible in normal eggs either living or in section, but in the case of sections of fertilized Arbacia eggs it can be seen as a vacuolated layer. The thickness of this layer was found to be 1.13 µ at the sperm aster stage and 1.50 µ at cleavage. In these eggs at cleavage, there were no signs either of differences in thickness at different regions of the surface or of a differentiated region of the cytoplasm ahead of the furrow. There were no clear indications of the presence of a vitelline membrane either in living or fixed eggs. A layer about 0.8 µ thick, pale with iron haematoxylin, was found at the edge of sections of unfertilized eggs which had been fixed in Bouin, but not with those which had been fixed in Flemming. This is probably the outer layer of the cortex which normally contains the cortical granules.

scholarly journals The soluble sperm factor that causes Ca2+ release from sea-urchin (Lytechinus pictus) egg homogenates also triggers Ca2+ oscillations after injection into mouse eggs

1999 ◽  
Vol 341 (1) ◽  
pp. 1-4 ◽  
Author(s):  
John PARRINGTON ◽  
Keith T. JONES ◽  
F. Anthony LAI ◽  
Karl SWANN
Keyword(s):  
Sea Urchin ◽  
Uncharacterized Protein ◽  
Lytechinus Pictus ◽  
Protein Factor ◽  
Chromatographic Columns ◽  
Sea Urchin Egg ◽  
Boar Sperm ◽  
Sperm Factor ◽  
Mammalian Eggs ◽  
Mouse Eggs

Cytosolic extracts of boar sperm contain a soluble phospholipase C (PLC) activity that induces Ca2+ release in sea-urchin (Lytechinus pictus) egg homogenates and an uncharacterized protein factor that causes Ca2+ oscillations when injected into mammalian eggs. In the present study we fractionated boar sperm extracts on three different FPLC chromatographic columns and found that the fractions that caused maximal Ca2+ release in sea-urchin egg homogenates were also the ones that triggered Ca2+ oscillations in mouse eggs. Our data suggests that the sperm factor which triggers Ca2+ oscillations in eggs contains a PLC and not the 33 kDa glucosamine deaminase previously suggested to be one its components.

Sign in / Sign up

Export Citation Format

Share Document