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Actin-mediated surface motility during sea urchin fertilization (1983)

Cline, Christi A. ; Schatten, Heide ; Balczon, Ron ; [et al.]

New York, NY : Wiley-Blackwell

Cell Motility and the Cytoskeleton 3 (1983), S. 513-524

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ISSN: 0886-1544

Keywords: fertilization ; actin ; microfilaments ; sea urchin ; cell division ; Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Medicine

Notes: The sea urchin egg at fertilization is an ideal model in which to study actin-mediated surface activity. Electron microscopy of unfertilized eggs demonstrates the presence of thousands of well-arrayed short microvilli, which appear supported by cytochalasin-sensitive actin oligomers as detected with rhodamine-labeled phalloidin staining of permeabilized eggs. At insemination, the previously short microvilli elongate and cluster around the successful sperm during incorporation. Phalloidin staining demonstrates a tremendous recruitement of polymerized actin into the site of sperm incorporation, resulting in the formation of the fertilization cone. Fertilization of cytochalasin-treated eggs results in the normal activation of the metabolic and bioeletric events, but sperm incorporation does not occur since the localized actin assembly required for fertilization cone formation is precluded. After sperm incorporation, the entire fertilized surface is restructured, as a result of a massive polymerization of actin to produce a burst in microvillar elongation. Addition of cytochalasin to eggs immediately following sperm incorporation demonstrates the recruitment of actin assembly for the proper progression through the first cell cycle. During normal cell divison, the egg surface retains the long microvilli. The furrow which forms at cytokinesis does not appear as a unique new structure, but rather as a reorganization of the cortical microfilaments. Quantitative fluorescence microscopy argues against an increase in microfilaments during early cytokinesis. At the latest stages of cytokinesis, a thickening of the cortical actin is noted, which could possibly be interpreted as a contractile ring. A minor basal level of actin assembly with numerous nucleation sites in unfertilized eggs and a tremendous but localized assembly of microfilaments surrounding the sperm during incorporation, followed by a massive global microfilament assembly event to elongate the fertilized egg microvilli resulting later in the reorganization of these microfilaments to produce the forces necessary for cytokinesis, highlight the utility of the study of sea urchin eggs at fertilization for understanding actin-membrane interactions.

Additional Material: 13 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/cm.970030518

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Microtubule-containing detergent-extracted cytoskeletons in sea urchin eggs from fertilization through cell division: Antitubulin immunofluorescence microscopy (1983)

Balczon, Ron ; Schatten, Gerald

New York, NY : Wiley-Blackwell

Cell Motility and the Cytoskeleton 3 (1983), S. 213-226

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ISSN: 0886-1544

Keywords: microtubules ; fertilization ; cell division ; sea urchin ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Medicine

Notes: The microtubule-containing structures that appear in eggs during fertilization and cell division in the sea urchins Lytechinus variegatus and Arbacia punctulata were detected by antitubulin immunofluorescence microscopy of detergent extracted cytoskeletal preparations. The extraction buffer, which is composed of 0.55 mM MgCl2, 10 mM EGTA, 25 mM MES, 25% glycerol, 1% Nonidet P-40, and 25 μM PMSF, pH 6.7, allows for dramatically improved fluorescent images compared to those obtained using conventional staining procedures, with residual background staining being reduced to near zero.The immunofluorescent images obtained using this technique provide information on several motile events that occur during the first cell cycle. This technique demonstrates that all of the cytoplasmic microtubules are associated with the incorporated sperm's centrioles during female pronuclear migration. This changes during the centration of the male and female pronuclei at which time a monastral array of microtubules forms in the egg's cytoplasm. A large proportion of the monastral microtubules do not appear to be associated with the centrioles. At prophase and early metaphase, the centrioles are the dominant microtubule organizing centers (MTOCs) consistent with mitotic theories that the kinetochore catches, but does not initiate, microtubules. Observations of intercentriolar distances show that there are three stages of pole separation during the first cell cycle. The initial separation occurs during pronuclear centration, the second during the streak stage, and the final one during the late stages of mitosis. At telophase, polar microtubules appear to extend into the cortex supporting the cell surface at all regions except the presumptive cleavage site.

Additional Material: 7 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/cm.970030303

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Cytoplasmic and sperm nuclear transformations in fertilized ammonia-activated sea urchin (Arbacia punctulata) eggs (1983)

Longo, Frank J.

New York, NY : Wiley-Blackwell

Gamete Research 8 (1983), S. 65-78

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ISSN: 0148-7280

Keywords: sea urchin ; ammonia-activation ; fertilization ; fertilization cone ; sperm asters ; pronuclear development ; Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology

Notes: Studies examining cytoplasmic and sperm nuclear transformations in sea urchin (Arbacia punctulata) eggs inseminated at different periods after ammonia activation have been caried out at the light- and electron-microscopic levels of observation. Arbaca eggs treated with ammonia-seawater demonstrated chromosome condensation after DNA synthesis and underwent a chromosome cycle similar to that described for Lytechinus [Mazia, 1947]. Cortical granule reaction, fertilization cone formation, and sperm aster development in eggs fertilized at 20 (interphase), 50 (prometaphase), and 180 (interphase) min after ammonia activation were structurally simialr to processes in untreated zygotes. Cyclical changes in the formation of fertilization cones and sperm asters, as reported for eggs fertilized after activation by agents that induce a cortical granule reaction, were not observed. Although sperm nuclear transformations were prolonged (14 vs 18 min), male pronuclei that developed in eggs fertilized 20 min after ammonia activation were morphologically similar to those observed in fertilized, untreated ova and incorporated 3H-thymidine. Sperm incorporated into eggs at 50 min after ammonia activation underwent nuclear envelope breakdown and chromatin despersion; however, 3H-thymidine incorporation was not observed, and male pronuclei rarely developed (less than 5% of all specimens examined). Subsequent to dispersion, the paternal chromatin condensed into chromosomes which were associated with an aster. These results demonstrate that although ammonia-activated eggs inseminated at interphase or prometaphase undergo similar cytoplasmic alterations, sperm nuclear transformations vary with the chromosome cycle of the egg.

Additional Material: 19 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/mrd.1120080108

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Acid release, cytoplasmic alkalinization, and chromosome condensation during sea urchin fertilization and amine-lnduced parthenogenesis (1983)

Lois, Augusto F. ; Neill, Dori J. ; Carroll, Edward J.

New York, NY : Wiley-Blackwell

Gamete Research 7 (1983), S. 123-132

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ISSN: 0148-7280

Keywords: parthenogenetic activation ; acid release ; sea urchin ; Strongylocentrotus purpurotus ; Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology

Notes: We have studied the relationship between acid release, cytoplasmic alkalinization, and the extent of chromosome condensation during parthenogenetic activation of sea urchin eggs. The relative rate of acid release in Strongylocentrotus purpuratus eggs was determined from pH measurements of egg suspensions. Acid release in inseminated eggs began after a lag of 0.4 min and the relative rate increased 108-fold, declined, and release was essentially complete by 8-min postinsemination. An average of 3.8 ± 0.23 × 10-12moles H+ cell- was released as determined by backtitration with NaOH. Acid release characteristics of eggs parthenogenetically activated with either NH4C1, methylamine ethylamine, n-propylamine, n-butylamine, or benzylamine were qualitatively similar. There was no detectable lag peroid and the increase in relative rate of acid release was directly proportional to the carbon number of the amine used, eg, from 8.3-fold methylamine to 470-fold with benzylamine. The total equivalents of acid released ranged from 0.50-8.2 × 10-12 moles H+·cell- in direct proportion to the concentration of amine used. The degree fo cytoplasmic alkalinization induced as a function of methylamine and benzylamine concentration was determined by pH measurements fo egg homogenates; egg cultures were also prepared for microscopic examination of chromosome condensation. None of the eggs had condensed chromosomes at 0.5-mM methylamine whereas a cytoplasmic alkalinization of 0.6 pH units was observed. Increased methylamine levels up to 10mM resulted in chromiosome condensation in only 20% of the eggs. A similar result was found with benzylamine. We conclude that acid release and cytoplasmic alkalinization during chemical parthenogenesis are insufficient to mimic sperm induction of chromiosome condensation and suggest that an additional factor(s) is required for chromosome condensation by low concentration of amines.

Additional Material: 4 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/mrd.1120070204

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Changes in cAMP-dependent protein kinase activity in the 10,000g sediment of sea urchin embryos during early development (1983)

Fujino, Yukio ; Yasumasu, Ikuo

New York, NY : Wiley-Blackwell

Gamete Research 7 (1983), S. 241-248

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ISSN: 0148-7280

Keywords: cAMP-dependent protein kinase ; cAMP ; sea urchin ; development ; Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology

Notes: cAMP-dependent protein kinase was found in the sediment obtained by centrifuging a homogenate of sea urchin embryos at 10,000g for 20 min, and was solubilized with 1% Triton X-100. This enzyme was eluted at 0.16 M NaCl in a linear concentration gradient on a DEAE-cellulose column, at which cAMP-dependent protein kinase found in the supernatant was also eluted. The enzyme activity was enhanced about 1.5-fold in the presence of 1 μM cAMP, and increased somewhat by adding cGMP or cIMP. The activation by cAMP of protein kinase in the sedimentable fraction was lower than in the supernatant fraction. The properties of the enzyme found in the 10,000g sediment and in the supernatant differ somewhat. The activity of the cAMP-dependent protein kinase in the 10,000g sediment was high in the embryos at the blastula, the swimming blastula, and the mesenchyme blastula stages. On the other hand, the activity was undetectable in unfertilized eggs and in embryos at the morula, the gastrula, and the pluteus stages.

Additional Material: 1 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/mrd.1120070305

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Change in phosvitin kinase activity during early development of the sea urchin (1983)

Fujino, Yukio ; Yasumasu, Ikuo

New York, NY : Wiley-Blackwell

Gamete Research 7 (1983), S. 249-257

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ISSN: 0148-7280

Keywords: phosvitin kinase ; protein kinase ; ATP production ; sea urchin ; Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology

Notes: Protein kinase, which phosphorylated phosvitin at the expense of ATP but did not phosphorylate casein, protamine, and histone mixture, was obtained by DEAE-cellulose column chromatography of the extract from the embryos of the sea urchin, Strongylocentrotus intermedius. This enzyme, partially purified by DEAE-cellulose column, reversibly catalyzed the reaction of phosvitin phosphorylation. This indicates that the sea urchin embryos contain phosvitin kinase. Phosvitin kinase in sea urchin embryos is somewhat different from that found in the other types of cells, which are able to phosphorylate casein as well as phosvitin. In unfertilized eggs, the activity of this enzyme was found only in the supernatant fraction obtained by centrifuging the homogenate at 10,000g for 20 min. The activity in the embryos at the swimming and the mesenchyme blastula stage was higher than in unfertilized eggs, and was localized in the sedimentable fraction obtained by centrifuging the homogenate of the embryos at 10,000g for 20 min. The highest activity of phosvitin kinase was observed in the embryos at the mesenchyme blastula stage, and the enzyme activity became quite low at the late gastrula stage. The activity and the intracellular distribution of phosvitin kinase changed during the development. The enzyme in this sedimentable fraction was not solubilized with 1% Triton X-100 but was extracted by 1 M NaCl.

Additional Material: 3 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/mrd.1120070306

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A species-specific sperm factor dispersing the jelly coat of the egg of the sea urchin, Anthocidaris crassispina (1983)

Yamada, Yuji ; Aketa, Kenji

New York, NY : Wiley-Blackwell

Gamete Research 8 (1983), S. 279-293

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ISSN: 0148-7280

Keywords: fertilization ; jelly coat ; species specificity ; sperm enzyme ; sea urchin ; Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology

Notes: A species-specific factor capable of disersing the jelly coat surrounding eggs has been purified from sperm of the sea urchin, Anthocidaris crassisina. It does not exert its effect on the vitelline layer. The purification has been accomlished by a four-step procedure involving ammonium sulfate fractionation, gel filtration on Sepharose CL-4B, ion-exchange column chromatography on DEAE-cellulose, and affinity column chromatograhy on heparin-Seharose CL-6B. The isolated factor is homogenous in sodium dodecyl sulfate polyacrylamide gel electrohoresis in the presence or absence of β-mercatoethanol, estimated molecular weight being about 140,000.The jelly dispersion by the present factor is activated by CaCl2, and inhibited by KCl, MnCl2, EDTA, and EGTA, and by sulfated saccharides such as chondroitin sulfate A and C, heparin, and glucose-6-sulfate, Inorganic sulfated such as (NH4)2SO4 and Na2SO4 have no effect on jelly dispersion. This factor is heat-labile, its activity in 30 min at 50°C.The present factor is found also in the seminal Plasma, and released from sperm themselves by treatment with Triton X-100 .These results suggest that this factor is loosely bound to the serm surface. Although glycosidase and arylsulfatase activities are detectable in the seminal plasma, these enzyme activities are not detectable in the purified jelly disersing factor.Only trypsin and α chymotrysin among commercial enzymes tested dispersing activity is inhibited neither by trypsin inhibitors such as N-α-p-tosyl-L-lysine-chloromethyl ketone, soybean trypsin inhibitor, ovomucoid trypsin inhibitor, nor by chymotrypsin inhibitors such as L-1-tosylamide-2 pheny-ethylcholoromethyl ketone and chymostatin Participation of trysin-like and chymotrypsin-like enzymes in jelly dispersion seems unlikely.

Additional Material: 10 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/mrd.1120080308

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