Base de dados : LILACS
Pesquisa : D08.811.277.656.300.760.030 [Categoria DeCS]
Referências encontradas : 9 [refinar]
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  1 / 9 LILACS  
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Texto completo SciELO Chile
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Id: lil-602970
Autor: Moreno, Ricardo D; Laserre A, Andrea; Barros, Claudio.
Título: Protease activity involvement in the passage of mammalian sperm through the zona pellucida
Fonte: Biol. Res;44(2):145-150, 2011. ilus.
Idioma: en.
Resumo: The interaction between acrosome-reacted sperm and zona pellucida proteins is not yet fully understood. Serine protease acrosin and its zymogen proacrosin have been proposed to fulfill this function due to their capacity to bind zona pellucida glycoproteins. However, the molecular mechanism underlying this interaction has been merely speculative. Here we show that fucoidan (a sulfated polysaccharide) and solubilized zona pellucida glycoproteins, but not soybean trypsin inhibitor, are able to detach bound spermatozoa, which suggests that live sperm binds to the zona pellucida in a non-enzymatical way. Interestingly, mild proteolytic digestion with acrosin or trypsin does not modify the structure of the zona pellucida, but rather results in fewer spermatozoa binding to the zona. These results agree with a model where the active site of acrosin digests the zona pellucida and binds through the polysulfate-binding domain through a three-dimensional zona structure rather than a single ligand.
Descritores: Acrosina/metabolismo
Reação Acrossômica/fisiologia
Serina Proteases/metabolismo
Espermatozoides/enzimologia
Zona Pelúcida/metabolismo
-Espermatozoides/fisiologia
Limites: Animais
Cricetinae
Masculino
Responsável: BR1.1 - BIREME


  2 / 9 LILACS  
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Texto completo SciELO Chile
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Id: lil-602969
Autor: de los Reyes, Mónica; Palomino, Jaime; Martínez, Víctor; Aretio, Carolina; Gutiérrez, Michel.
Título: Acrosin release and acrosin activity during incubation in capacitating media using fresh and frozen-thawed dog sperm
Fonte: Biol. Res;44(2):139-144, 2011. ilus.
Idioma: en.
Projeto: FONDECYT; . MDLR.
Resumo: We evaluated the effect of time and temperature on acrosin release from the acrosomal cap and the activity of this enzyme during in vitro capacitation in fresh and frozen/thawed dog sperm. Sperm-rich fractions of six ejaculates from three dogs were processed as fresh and frozen samples. Each sperm sample was incubated in canine capacitation medium (CCM) for 0, 1, 2 and 3 h at 20°C and at 37°C. After incubation, the samples were assessed by the indirect immunofluorescent staining technique. The probability of having unlabeled sperm (PUS), indicating acrosin loss, was modelled by a binomial distribution using logistic regression. There was a linear relationship between PUS and time at both temperatures (p<0.001); however, a major percentage of unlabeled sperm was observed in frozen/thawed samples soon after incubation, indicating that the release of acrosin was affected by capacitation time, mainly in frozen samples. Temperature influenced acrosin release only in cryopreserved sperm (p<0.05). Acrosin activity was measured by digestion halos on slides coated with gelatin-substrate film during each time period; a significant increase in the number of large halos was observed in fresh samples throughout the experiment, whereas frozen/thawed sperm showed a decreased rate of halo diameters during culture. Thus, there appears to differences between fresh and frozen dog sperm in terms of acrosin release and the level of acrosin activity in the course of in vitro capacitation.
Descritores: Acrosina/metabolismo
Preservação do Sêmen/veterinária
Capacitação Espermática/fisiologia
Espermatozoides/enzimologia
-Acrosina/fisiologia
Criopreservação/veterinária
Técnica Indireta de Fluorescência para Anticorpo/veterinária
Preservação do Sêmen/métodos
Motilidade Espermática/fisiologia
Espermatozoides/fisiologia
Temperatura Ambiente
Fatores de Tempo
Limites: Animais
Cães
Masculino
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


  3 / 9 LILACS  
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Id: lil-405203
Autor: Rosatti, M. I; Beconi, Martha T; Córdoba, M.
Título: Proacrosin-acrosin activity in capacitated and acrosome reacted sperm from cryopreserved bovine semen
Fonte: Biocell;28(3):311-316, dic. 2004. ilus, tab.
Idioma: en.
Resumo: Acrosin activity is associated with normal fertility in human and bovine spermatozoa. The aim of the study was to determine the variation of the enzyme activity in the proacrosin-acrosin system in capacitated and acrosome recated cryopreserved bovine sperm. Enzyme activity was assessed spectrophotometrically using N-alpha-benzoyl-DL-arginine p-nitroanilide (BAPNA) as specific substrate for acrosin at pH 8. Capacitation with heparin and quercitin failed to induce conversion of proacrosin to acrosin. An increase in acrosin activity produced by the presence of progesterone, in a dose-dependent manner, was related with the induction of true acrosome reaction. The total level of acrosin activity registered showed that 96 per cent of acrosin of capacitated sperm samples and control is present in the zymogen form. Moreover, progesterone is capable of duplicating the level of active enzyme, indicating that enzyme activity changes are related to acrosome reaction, suggesting that only a minor proportion of the total of proacrosin-acrosin system is required in the exocytotic process on cryopreserved bovine sperm.
Descritores: Acrosina/metabolismo
Capacitação Espermática/fisiologia
Espermatozoides
Precursores Enzimáticos/metabolismo
Quercetina/análogos & derivados
Quercetina/farmacologia
Reação Acrossômica/fisiologia
Sêmen/citologia
-Azul Tripano/química
Criopreservação
Clortetraciclina/química
Espermatozoides/enzimologia
Espermatozoides/fisiologia
Heparina/farmacologia
Microscopia de Fluorescência
Microscopia de Interferência
Progesterona/farmacologia
Limites: Bovinos
Animais
Responsável: AR1.1 - Biblioteca Rafael Herrera Vegas


  4 / 9 LILACS  
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Id: lil-336000
Autor: Sillerico, T; Valdivia, M; Ioannes, A. de; Barros, C.
Título: Proacrosin and acrosin determination during capacitation and acrosome reaction in rabbit spermatozoa
Fonte: Biocell;20(2):133-142, Aug. 1996.
Idioma: en.
Resumo: The proacrosin/acrosin system has been immunolocalized, by the silver enhanced immunogold technique on the acrosomal region of capacitated and perivitelline rabbit spermatozoa. The purpose of the present work was to investigate the kinetics of the activation of acrosin by determining the proportion of proacrosin and acrosin present in the acrosome of the rabbit spermatozoa during capacitation and the induction of the acrosome reaction by the calcium ionophore A23187. Rabbit spermatozoa selected by the percoll gradient technique were incubated for 0, 0.5 and 6 hours and then the acrosome reaction was induced at 0 and 6 hours with 1.9 microM of the calcium ionophore A23187. It was found that 95 of acrosin activity in rabbit spermatozoa at zero time corresponds to proacrosin and after capacitation and acrosome reaction, a diminution of the activity of proacrosin/acrosin system was found. However, proacrosin represents the large majority of the system activity. Western blot prepared with sperm extract obtained at the start of incubation showed the characteristic doublet band about 53-55 kDa that may correspond to proacrosin and alpha-acrosin. After six hours of incubation and with induction with the calcium ionophore A23187 the same doublet was seen in addition to a third band of 49 kDa that could correspond to a transition form between alpha-acrosin to beta-acrosin. In conclusion, rabbit proacrosin/acrosin system remains in the large proportion as proacrosin during capacitation and acrosome reaction.
Descritores: Acrosina
Técnicas In Vitro
Precursores Enzimáticos/metabolismo
Espermatozoides
-Acrossomo
Capacitação Espermática/fisiologia
Imuno-Histoquímica
Cinética
Limites: Animais
Masculino
Coelhos
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


  5 / 9 LILACS  
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Id: lil-317649
Autor: Vázquez-Levin, Mónica H; Furlong, Laura; Zahn, Astrid.
Título: Acrosina humana: aspectos estructurales y funcionales / Human acrosin: structural and functional aspects
Fonte: Bol. Inf. Soc. Argent. Androl;7(2):28-42, jul. 1998. tab, graf.
Idioma: es.
Descritores: Acrosina
Limites: Seres Humanos
Tipo de Publ: Revisão
Responsável: AR364.1 - Biblioteca


  6 / 9 LILACS  
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Id: lil-285439
Autor: Morales, Patricio; Socias, Teresa; Cortez, Jacqueline; Llanos, Miguel.
Título: Evidencias de la presencia de una actividad tipo-quimotripsina en el espermatozoide humano y su rol en la reacción acrosómica / Evidence of the quimiotrypsin activity in the human spermatozoid and its role in the acrosomic reaction
Fonte: Biofarbo;4(4):15-26, dic. 1995. ilus.
Idioma: es.
Resumo: Se evaluó el efecto de inhibidores de la quimotripsina sobre la reacción acrosómica del espermatozoide humano estimulada por la zona pelúcida o fluido folicular humano. Espermatozoides mótiles, seleccionados por un gradiente de Percol, fueron incubadas en una concentración de 1x 10 células/ml, a 37 grados centigrados, y 5 por ciento de CO2. Después de 4.5 hrs. Se añadió el inhibidor de quimotripsina TPCK (N- Tosyl-L-Phenylalanine-Chloromethyl Ketone) o el sustrato ATEE (N-Acetyl-L-Tyrosine Ethyl Ester) por 30 minutos. Luego, se añadieron cuatro ovocitos humanos y se determinó el porcentaje de reacción acrosómica sobre la zona pelúcida. El TPCK y el ATEE inhibieron la reacción acrosómica producida por la zona pelúcida. Los inhibidores de quimotripsina TPCK y quimostatina y los sustratos para quimotripsina ATEE, BTEE (N-Benzoyl-Tyrosine-Ethyl Esther), Succinyl-Ala-Ala-Phe-7-Amido-4 Methyl-Coumarin (Suc-Ala-Ala-Phe-AMC), y Succynil-Leu-Leu-Val-Try-7-Amido-4 Methyl-Coumarin (Suc-Leu-leu-Val-Tyr-AMC) inhibieron la reacción acrosómica inducida por el fluido folicular humano. Los extractos espermáticos mostraron una actividad hidrolítica hacia los sustratos Suc-Ala-Ala-Phe-AMC y Suc-Leu-Leu-Val-Tyr-AMC. Esta actividad enzimática fue anulada por el TPCK y la quimostatina, en ausencia de Ca2+ y no fue modificada por la 1,10 fenantrolina. Además, esta actividad estuvo presente en el sobrenadante después de que la reacción acrosómica fue inducida por el ionóforo de calcio y en espermatozoides epidídimales recuperados de la región caudal. Observaciones con el microscopio electrónico indicaron que los inhibidores impidieron los eventos de membrana de la reacción acrosómica. Estos datos sugieren una asociación entre el espermatozoide humano y una actividad tipo quimotripsina con un posible rol en la reacción acrosómica
Descritores: Quimotripsina
-Acrosina
Bolívia
Espermatozoides
Limites: Seres Humanos
Responsável: BO3.1 - Biblioteca


  7 / 9 LILACS  
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Id: lil-228638
Autor: Yunes, R; Melendez, J; Valdivia, M; Barros, C.
Título: Golden hamster perivitelline spermatozoa do not show proacrosin/acrosin at the inner acrosomal membrane
Fonte: Biol. Res;25(2):91-3, 1992. ilus.
Idioma: en.
Resumo: It has been suggested that acrosin may function in penetration of the zona pellucida and of the highly structured extracellular matrix of the perivitelline space. In this study we investigated whether golden hamster perivitelline spermatozoa contain proacrosin/acrosin, as evidenced by the silver enhanced immunogold technique using the monoclonal antibody antiacrosin C2E5. None of the 197 spermatozoa recovered from the perivitelline space showed proacrosin/acrosin associated with the acrosomal region, suggesting that acrosin would not play a role in the penetration of the perivitelline extracellular matrix
Descritores: Acrosina/metabolismo
Precursores Enzimáticos/metabolismo
Membranas Intracelulares/metabolismo
Espermatozoides/metabolismo
-Senescência Celular
Mesocricetus
Oócitos/fisiologia
Interações Espermatozoide-Óvulo
Membrana Vitelina
Limites: Animais
Feminino
Cricetinae
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


  8 / 9 LILACS  
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Id: lil-228631
Autor: Barros, C; Capote, C; Perez, C; Crosby, J. A; Becker, M. I; Ioannes, A. de.
Título: Immunodetection of acrosin during the acrosome reaction of hamster, guinea-pig and human spermatozoa
Fonte: Biol. Res;25(1):31-40, 1992. ilus, tab.
Idioma: en.
Resumo: Mammalian sperm acrosomes contain a trypsin-like protease called acrosin which causes limited and specific hydrolysis of the extracellular matrix of the mammalian egg, the zona pellucida. Acrosin was localized on hamster, guinea-pig and human sperm using monoclonal and polyclonal antibodies to human acrosin labelled with colloidal gold. This was visualized directly with transmission electron microscopy, and with light and scanning microscopy after silver enhancement of the colloidal gold probe. Four distinct labelling patterns were found during capacitation and the acrosome reaction in hamster and guinea-pig spermatozoa, and three patterns were found in human spermatozoa. In the hamster, acrosin was not detected on the inner acrosomal surface after the completion of the acrosome reaction, thus correlating with the observation that hamster spermatozoa lose the ability to penetrate the zona after the acrosome reaction. With guinea-pig and human spermatozoa, acrosin was still detected after the completion of the acrosome reaction, thus correlating with the observation that acrosome reacted guinea-pig spermatozoa bind to and penetrate the zona pellucida
Descritores: Acrosina/análise
Acrossomo/fisiologia
Óvulo/fisiologia
Interações Espermatozoide-Óvulo
-Acrossomo/enzimologia
Acrossomo/ultraestrutura
Microscopia Imunoeletrônica
Zona Pelúcida/fisiologia
Limites: Animais
Feminino
Cobaias
Cricetinae
Tipo de Publ: Estudo Comparativo
Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


  9 / 9 LILACS  
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Id: lil-157839
Autor: Sillerico S., Teresa; Ascarrunz G., M. Eugenia.
Título: Actividad proteolitica de la Acrosina como parametro para evaluar el estado Acrosomico y predecir el potencial de fertilidad del espermatozoide humano / Proteolitic activity of Acrosine as a parameter to evaluate the acrosomic states and predict fertility of human spermatozoid
Fonte: Cuad. Hosp. Clín = Cuad. - Hosp. clín;40(1):15-22, 1994. tab.
Idioma: es.
Resumo: El presente trabajo fue orientado a la identificacion de un metodo de extraccion de la Acrosina control de la densidad espermatica despues de la extraccion, control de calidad para la eliminacion de contaminantes y el estudio de parametros cineticos de la enzima (concentracion de substrato, enzima, pH, temperatura, tiempo de reaccion). Se estudiaron 104 muestras de liquido seminal, los cuales fueron clasificados de acuerdo a criterios de la OMS. En todos los grupos clasificados se determinaron la actividad catalitica de la Acrosina y los parametros seminologicos. Se concluye que la determinacion de la actividad catalitica de la Acrosina discrimina entre los acrosomas indemnes de los espermatozoides normales; y los acrosomas con alteraciones de las membranas acrosomicas en espermios defectuosos por lo tanto evalua la capacidad de fertilidad del espermatozoide humano, siendo un importante parametro adicional el simograma de rutina, y un requisito para la fertilizacion in vitro e inseminacion artificila.
Descritores: Acrosina/análise
Acrosina/biossíntese
Espermatozoides/química
Espermatozoides/fisiologia
Limites: Seres Humanos
Masculino
Adolescente
Adulto
Meia-Idade
Tipo de Publ: Relatos de Casos
Responsável: BO6.1 - Biblioteca



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