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  • 1
    Electronic Resource
    Electronic Resource
    Anti-inflammatory drugs promote polyspermic fertilization in sea urchins (1984)
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 9-19 
    Details
    ISSN: 0148-7280
    Keywords: fertilization ; polyspermy ; sea urchin eggs ; sperm peroxidase ; anti-inflammatory drugs ; cyclooxygenase ; prostaglandins ; arachidonic acid cascade ; indomethacin ; flufenamic acid ; meclofenamate ; aspirin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Sea urchin eggs are known to release H2O2 during the cortical reaction at fertilization to help prevent polyspermy by inactivating excess sperm in the vicinity. This process resembles the peroxidatic killing of bacteria by phagocytic leukocytes during inflammation. Associated with these reactions in leukocytes, arachidonic acid is released from phospholipids and can be oxidized via the cyclooxygenase pathway to produce prostaglandins. Nonsteroidal anti-inflammatory drugs (NSAID) that are cyclooxygenase inhibitors in somatic cells were used to determine whether Arbacia punctulata and Strongylocentrotus purpuratus eggs use these processes to help prevent polyspermy. The potent cyclooxygenase inhibitor indomethacin causes a dose (10-100 μM) and sperm density dependent induction of polyspermy if added before the egg completes the cortical reaction. It does not retard elevation of the fertilization envelope and does not promote polyspermy by protecting sperm from peroxidatic inactivation by egg-derived H2O2. Other potent cyclooxygenase inhibitors, flufenamate and meclofenamate, also induce polyspermy at 10-60 μM. Aspirin, a weak cyclooxygenase inhibitor in somatic cells, does not cause polyspermy at 5 mM. These findings provide evidence that prostaglandins or other cyclooxygenase-derived metabolites may help assure monospermic fertilization in sea urchins.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120100103
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  • 2
    Electronic Resource
    Electronic Resource
    Characterization of cell surface polypeptides of unfertilized, fertilized, and protease-treated zona-free mouse eggs (1989)
    New York, NY : Wiley-Blackwell
    Gamete Research 23 (1989), S. 91-101 
    Details
    ISSN: 0148-7280
    Keywords: fertilization ; zona-free egg ; membrane polypeptides ; radioiodination ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The polypeptide composition of unfertilized, fertilized, and protease-treated zona-free mouse eggs was evaluated in this study. Zona-free eggs were radioiodinated by an Iodogen-catalyzed reaction. Light microscopic autoradiography of egg sections revealed that labeling was restricted to the cell surface. Labeled eggs were solubilized, and cell surface polypeptides were identified by one-dimensional SDS polyacrylamide gel electro-phoresis and autoradiography. The unfertilized egg demonstrated 8-10 peptides that incorporated125I, with major bands observed at approximately 145-150, 94, and 23 kilo-daltons (kD). Zona-free eggs fertilized in vitro and then radiolabeled demonstrated several new bands in comparison to unfertilized eggs, with a major band appearing at approxi mately 36 kD. Treatment of radiolabeled unfertilized eggs with either trypsin or chymo-trypsin (1 mg/ml for 5-20 min) caused enzyme-specific modifications in labeled polypep tides. Trypsin (T) treatment resulted in time-dependant modification of the three major peptides at 145-150,94, and 23 kD. Chymotrypsin (CT) treatment, in contrast, was asso ciated with loss or modification of the 94 kD band, with no apparent effect on either the 145-150 or 23 kD band. Taken together with previous data indicating that T or CT egg treatment interferes with sperm-egg attachment and fusion (Boldt et al.: Biol Reprod 39:19-27, 1988), these results suggest a possible role for the 94 kD protein in sperm-egg interaction.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120230109
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  • 3
    Electronic Resource
    Electronic Resource
    A separate catalase and peroxidase in sea urchin sperm (1984)
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 267-281 
    Details
    ISSN: 0148-7280
    Keywords: sea urchin sperm ; catalase ; peroxidase ; phenylhydrazine ; 3-amino-1,2,4-triazole ; azide ; fertilization ; polyspermy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The release of hydrogen peroxide (H2O2) by the fertilized sea urchin egg has been shown to assist in the prevention of polyspermy [Coburn et al, 1981; Boldt et al, 1981]. Physiological data suggested that egg-derived H2O2 reacts with a phenylhydrazine-sensitive sperm peroxidase to inactivate sperm, while a 3-amino-1,2,4-triazole-sensitive catalase acts to protect sperm from H2O2 [Boldt et al, 1981]. Strongylocentrotus purpuratus sperm contain heat and pronase labile catalase and peroxidase activities. Differential extraction of sperm (hypotonic phosphate buffer for catalase and Triton X-100 at high ionic strength for peroxidase) results in complete separation of these enzyme activities. The catalase is highly sensitive to inhibition by azide and 3-amino-1,2,4-triazole, and less sensitive to inhibition by phenylhydrazine. The peroxidase is highly sensitive to inhibition by phenylhydrazine and relatively insensitive to 3-amino-1,2,4-triazole and azide. These results show that two distinct H2O2 reactive enzymes, catalase and peroxidase, are present in sea urchin sperm, and are consistent with our hypothesis concerning the biological functions of these enzymes in fertilization.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120100306
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  • 4
    Electronic Resource
    Electronic Resource
    Isolation of 125I-concanavalin A-labeled plasma membrane from unfertilized mouse eggs (1987)
    New York, NY : Wiley-Blackwell
    Gamete Research 16 (1987), S. 303-310 
    Details
    ISSN: 0148-7280
    Keywords: Zona-free mouse egg ; plasma membrane ; concanavalin A ; fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A procedure was developed for isolation of plasma membrane (PM) preparations from unfertilized mouse eggs. Zona-free mouse eggs prepared by the method of Boldt and Wolf (Gamete Res 13:213-222, 1986) were labeled with 125I-concanavalin A (ConA) prior to sonication and fractionation on iso-osmotic self-generated Percoll density gradients. Experiments using the ConA-specific sugar α-methylmannoside (αMM) indicated that 125I-ConA bound specifically to the egg PM. Greater than 95% of 125I-ConA binding to zona-free eggs was blocked in the presence of 0.1 M αMM, and incubation of eggs in αMM after 125I-ConA labeling caused release of 85-90% of bound label. Fractionation of 125I-ConA-labeled eggs by Percoll density gradient centrifugation yielded a single radioactive peak at density = 1.025, corresponding to egg PM material. Prolonged incubation of 125I-ConA-labeled eggs or egg sonicates prior to fractionation did not alter the location of the radioactive peak, indicating that 125I-ConA did not label other organelles. As a control, human erythrocytes were labeled with 125I-ConA and fractionated under identical experimental conditions and yielded a single radioactive peak at density (1.020) comparable to that observed for 125I-ConA-labeled eggs. These results indicate that 125I-ConA can be used as a specific marker to support PM isolation from small numbers of zona-free mouse eggs.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120160404
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  • 5
    Electronic Resource
    Electronic Resource
    Recovery of penetration ability in protease-treated zona-free mouse eggs occurs coincident with recovery of a cell surface 94 kD protein (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 33 (1992), S. 46-52 
    Details
    ISSN: 1040-452X
    Keywords: Sperm-egg interaction ; Fusion ability ; Cyclohexamide ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Previous studies have demonstrated that protease treatment of zona-free mouse eggs impairs sperm-egg interaction (Boldt et al.: Biol Reprod 39:19-27. 1988) and causes modification of a 94 kD egg plasma membrane protein (Boldt et al., Gamete Res 23:91-101, 1989), In this report, the ability of eggs to recover penetration ability following protease treatment was examined. Zona-free mouse eggs were isolated and treated with either trypsin or chymotrypsin (1 mg/ml, 20 min), then cultured for 0, 3, or 6 hr before insemination. Eggs cultured for 3 or 6 hr displayed significantly higher penetration levels than eggs inseminated immediately after protease treatment, indicating a recovery of penetration ability during the 3 or 6 hr incubation period. The recovery of penetration ability was not blocked by inclusion of cyclohexamide (50 μg/ml) during the 3 or 6 hr culture period, indicating that protein synthesis was not required for recovery of fusion ability. Cell surface radiolabeling studies with 125I revealed that a 94 kD cell surface protein was lost immediately following trypsin or chymotrypsin treatment but was found on the egg surface after the 3 or 6 hr recovery period. Recovery of the 94 kD egg surface protein occurred in the presence of cyclohexamide, and metabolic radiolabeling studies with 35S-methionine confirmed that synthesis of a 94 kD protein was blocked by cyclohexamide. These results suggest that the recovery of penetration ability after protease treatment of zona-free eggs is due to recovery of the 94 kD cell surface protein, providing further evidence for the involvement of the 94 kD protein in sperm-egg interaction. © 1992 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080330107
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  • 6
    Electronic Resource
    Electronic Resource
    Mechanistic studies of the plasma membrane block to polyspermy in mouse eggs (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 34 (1993), S. 65-72 
    Details
    ISSN: 1040-452X
    Keywords: Egg plasma membrane ; Egg activation ; Sperm binding ; Ethanol ; Strontium chloride ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The mechanisms responsible for the plasma membrane associated block to polyspermy in mouse eggs were studied. Reinsemination experiments using zona-free eggs indicated that, after fertilization, the egg plasma membrane is altered such that sperm binding to the egg plasma membrane is blocked, except in the region of the second polar body. Activation of the egg with either ethanol or strontium chloride did not result in a block to polyspermic penetration, as artificially activated eggs displayed identical penetration levels as to nonactivated control eggs. The penetrability of activated eggs was not altered by the presence or absence of the zona pellucida during activation. Lectin staining for egg cortical granule material indicated that activation did cause cortical granule exocytosis; however, activated eggs remained penetrable. These data support the following conclusions: (1) an alteration in the ability of the egg plasma membrane to allow sperm adherence accounts for the block to polyspermy; (2) establishment of the plasma membrane block to polyspermy is sperm dependent, since artificial egg activation does not result in a block response; (3) the contents of the egg's cortical granules do not play a role in the establishment of the plasmalemma block response. © 1993 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080340111
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  • 7
    Electronic Resource
    Electronic Resource
    An improved method for isolation of fertile zona-free mouse eggs (1986)
    New York, NY : Wiley-Blackwell
    Gamete Research 13 (1986), S. 213-222 
    Details
    ISSN: 0148-7280
    Keywords: fertilization ; zona-free egg ; chymotrypsin ; plasma membrane ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Studies of sperm-egg fusion using zona-free mouse eggs are impaired by the procedures used for removal of the zona pellucida. Methods involving proteolytic digestion or mechanical aspiration through micropipettes are limited in that proteases can adversely affect fertility and mechanical removal often results in low egg yields. An efficient procedure for preparation of zona-free mouse eggs was developed using a combined enzymatic (chymotrypsin) mechanical approach (CT-M procedure). Zona-intact eggs, obtained after hyaluronidase treatment, were exposed to 0.001% α-chymotrypsin in medium containing 0.5% bovine serum albumin (BSA). Brief (2 minute) exposure to chymotrypsin under these conditions caused pronounced zona distention in a majority (80-90%) of the eggs, facilitating mechanical removal and resulting in a high yield of zona-free eggs. Eggs prepared by the CT-M method displayed identical penetration levels relative to mechanically denuded eggs. CT-M prepared eggs also showed sperm concentration dependent penetration levels and demonstrated a plasma membrane block to polyspermy, qualities previously observed in mechanically prepared eggs [Wolf DP, 1978, Dev Biol 64:1-10]. Eggs could be exposed to 0.001% CT for zona distention over a 2-10-minute time period with no detrimental effects on fertility. The effect of chymotrypsin was also studied by treating zona-free eggs for 30 minutes over a 1-1,000-μg/ml range of enzyme, and a concentration-dependent reduction in penetration levels was observed. These results indicate that the CT-M method is a useful procedure for the isolation of large numbers of zona-free mouse eggs.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120130304
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  • 8
    Electronic Resource
    Electronic Resource
    Reaction of sperm with egg-derived hydrogen peroxide helps prevent polyspermy during fertilization in the sea urchin (1981)
    New York, NY : Wiley-Blackwell
    Gamete Research 4 (1981), S. 365-377 
    Details
    ISSN: 0148-7280
    Keywords: block to polyspermy ; hydrogen peroxide ; sperm peroxidase ; sperm catalase ; cortical reaction ; fertilization ; phenylhydrazine ; 3-amino-1,2,4-triazole ; ovoperoxidase ; sea urchin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Recent evidence suggests roles for egg derived hydrogen peroxide (H2O2) and ovoperoxidase (secreted by cortical granules) in both fertilization envelope hardening and the block to polyspermy in sea urchins. Strongylocentrotus purpuratus eggs were found to release H2O2 during the cortical reaction at fertilization. Treatment of sperm with equivalent concentrations of H2O2 resulted in a rapid loss of sperm fertilizing ability. Attempts were made to induce polyspermy by utilizing ovoperoxidase inhibitors at concentrations known to inhibit fertilization envelope hardening. Eggs fertilized in phenylhydrazine became polyspermic, while 3-amino-1,2,4-triazole-treated eggs did not. These data suggested that a sperm peroxidase might be involved in preventing polyspermy. This hypothesis was tested by the addition of phenylhydrazine or 3-amino-1,2,4-trizaole to H2O2-treated sperm. Phenylhydrazine acted to protect sperm fertility from H2O2, while 3-amino-1,2,4-triazole increased the adverse effect of H2O2. Simultaneous addition of both inhibitors to sperm incubated in H2O2 gave an intermediate value of sperm fertility. These data indicate that (1) H2O2 generated by sea urchin eggs during the cortical reaction at fertilization is used for two separate processes, fertilization envelope hardening and the prevention of polyspermy; (2) ovoperoxidase is probably not involved in preventing polyspermy; and (3) egg-derived H2O2 reacts directly with sperm enzymes to prevent polyspermy. The phenylhydrazine-sensitive enzyme in the sperm is probably a peroxidase that acts to inactivate sperm, while the 3-amino-1,2,4-triazolesensitive enzyme is probably a catalase which protects sperm from H2O2. This hypothesis is consistent with model experiments on horseradish peroxidase and bovine liver catalase.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120040502
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