Manipulation of chromosome condensation by protein synthesis inhibitors and cyclic AMP during maturation of bovine oocytes

Milovanov, Cornelia; Sirard, Marc‐André

doi:10.1016/0093-691x(94)90498-8

Cited by 12 publications

(5 citation statements)

References 17 publications

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“…It was concluded that the bulk and distribution of cyclins in pronuclei are closely related to the progression of the first interphase after fertilization. In addition, Sirard and colleagues Milovanov and Sirard, 1994) have shown that inhibition of protein synthesis in bovine oocytes maintains the chromatin in a decondensed state. This finding clearly demonstrated that the activity of some products is involved directly or indirectly in activating the proteins performing DNA replication and repair.…”

Section: Discussionmentioning

confidence: 97%

Effect of microinjection time during postfertilization S‐phase on bovine embryonic development

Gagné

Pothier

Sirard

1995

Molecular Reproduction Devel

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Microinjection into bovine zygotes was performed to evaluate the effects of the timing of injection during the phase of DNA replication on the subsequent in vitro development of embryos and expression of injected chicken beta-actin promoter-lac Z gene construct. The period of DNA replication of bovine zygotes, determined by 3H-thymidine incorporation, begins between 12 hr and 13 hr postinsemination (hpi) of in vitro matured oocytes, reaches a maximum from 17 hpi to 19 hpi, and is complete by 21-22 hpi. Aphidicolin, an inhibitor of DNA polymerase alpha, was used to synchronize the pronuclei and the zygote population. Treatment with aphidicolin at 9-18 hpi arrested DNA replication without affecting formation of the pronuclei or embryo development. Cycloheximide, an inhibitor of protein synthesis, was used for nucleocytoplasmic resynchronization of the aphidicolin-treated zygotes. Microinjection was performed at 15 (early), 18 (mid), and 21 (late S phase) hpi. Embryonic development was affected following each of the three microinjection times. The development of zygotes injected at 18 hpi was significantly higher (P < 0.01) after 5 days of culture than those injected at 15 hpi or 21 hpi. Expression of the marker gene was observed in the higher stage of development (> 16 cells) only in the zygotes injected at 18 hpi. At the earlier stages of development, the proportions of embryos showing expression of the foreign gene were the same for all microinjection times. In aphidicolin- and cycloheximide-treated zygotes, expression of the marker gene followed the same curve as development, i.e., expression was low when injected early or late and higher (P < 0.005) when injected in the middle of zygotic S phase. The ability of the embryos to survive microinjection and to express the marker gene as a function of hpi seems to be influenced mostly in the cytoplasm processing stage rather than the pronuclei processing stage.

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Section: Discussionmentioning

confidence: 97%

Effect of microinjection time during postfertilization S‐phase on bovine embryonic development

Gagné

Pothier

Sirard

1995

Molecular Reproduction Devel

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“…It has been shown that a brief inhibition of protein synthesis can activate mouse oocytes (Siracusa et al, 1978;Clarke and Masui, 1983). The effects of a protein synthesis inhibitor strongly suggest that the inhibition of the synthesis of certain proteins leads to the interruption of the second meiotic arrest (Milovanov and Sirard, 1994). Thus, it appears that the maturational arrest of bovine occytes depends on the synthesis of some proteins.…”

Section: Discussionmentioning

confidence: 99%

“…Since early experiments, oocytes from a variety of mammalian species have been successfully activated to induce a state of parthenogenetic development. A number of physical and chemical stimuli are known to induce parthenogenetic activation of oocytes, including electrical currents (Tarkowski et al, 1970;Ware et al, 19891, hyaluronidase (Graham, 1970;Kaufman, 19731, ionophores (Steinhardt et al, 1974;Ware et al, 19891, ethanol (Cuthbertson, 1983;Nagai, 1987), and protein synthesis inhibitors (Siracusa et al, 1978;Clarke and Masui, 1983;Milovanov and Sirard, 1994). Although it was believed that the maturational age of bovine oocytes is the main determinant of activation ability (Ware et al, 19891, the competence of oocytes undergoing parthenogenetic activation after in vitro maturation is poorly understood.…”

Section: Introductionmentioning

confidence: 99%

Effects of cumulus cells and follicle‐stimulating hormone during in vitro maturation on parthenogenetic activation of bovine oocytes

Chian

Sirard

1995

Molecular Reproduction Devel

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The response to parthenogenetic activation (calcium ionophore A23187) of bovine oocytes after 30 hr of culture in different maturation conditions was evaluated. The activation rates of oocytes in response to 10 mu M A23187 were similar (86% +/- 4 vs. 89% +/- 8) when the oocytes matured with or without cumulus cells were cultured in TCM-199 + 10% fetal calf serum (maturation medium [MM]) alone. However, the activation rates were significantly lower in oocytes matured with than without cumulus cells (48 +/- 10 vs. 79% +/- 16; P < 0.05) when MM was supplemented with 0.5 microgram/ml follicle-stimulating hormone (FSH), 50 micrograms/ml luteinizing hormone (LH), and 1.0 microgram/ml estradiol-1 beta (E2). When oocytes with cumulus cells were cultured in different media, MM along, MM + 0.5 microgram/ml FSH, MM + 50 micrograms/ml LH, MM + 1.0 microgram/ml E2, and MM + all three hormones, the percentages of activated oocytes were 91% +/- 3.52% +/- 14.83% +/- 7, 83% +/- 13, and 54% +/- 7, respectively. Oocytes with or without cumulus cells during culture began to form a pronucleus 5 hr after activation (5% +/- 1 and 7% +/- 1, respectively). Finally, the proteins synthesized by oocytes matured with or without cumulus cells before (3 hr) and after (10 hr) activation was labelled with [35S]methionine for analysis. Before activation, a 47 kD protein complex was produced by cumulus cell-intact oocytes. An active protein synthesis of 60 kD was characteristic for the oocytes with cumulus cells cultured in MM containing 0.5 micrograms/ml FSH. After activation, there was an appearance of proteins at 75 kD and 47 kD in the oocytes with cumulus cells but not in the oocytes without cumulus cells during the maturation period. These results indicate that bovine oocytes matured in vitro have different capacities for parthenogenetic activation depending on the presence or absence of cumulus cells and the presence of FSH in MM during culture.

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“…Na segunda divisão meiótica, a fase de prófase II, caracterizada por ocorrer de forma rápida e, às vezes, inexistente avança até a fase de metáfase II, culminando com a segunda parada da meiose, estando o oócito nuclear e citoplasmaticamente apto para reiniciar o processo. Para a retomada da meiose, o oócito deverá ser fecundado pelo espermatozóide, então, no núcleo oocitário ocorrerá, sucessivamente, os estádios de anáfase II e telófase II, expulsão do segundo corpúsculo polar e formação do oócito haplóide fecundado, determinando o encerramento do processo da oogênese (MILOVANOV; SIRARD, 1994;RUMPF et al, 1995;.…”

Section: Introductionunclassified

Índice De Recuperação De Oócitos Bovinos Obtidos De Ovários Adquiridos Em Abatedouro Como Contribuição Para Os Estudos De Fecundação E Produção De Embriões in Vitro

Agostinho¹,

Léga²

2009

Nucleus Animal.

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resumo: A produção in vitro de embriões é uma biotécnica utilizada, alternativamente, para acelerar a produção de animais geneticamente superiores além de permitir o aprofundamento dos conhecimentos relativos aos processos fisiológicos, bioquímicos e biotecnológicos da espécie animal de interesse. O desenvolvimento de técnicas in vitro para a produção de embriões de animais domésticos tem grande potencial tanto para pesquisa básica quanto para aplicações a campo e tem sido muito utilizadas e difundidas no Brasil e no mundo. O presente trabalho objetivou classificar oócitos bovinos obtidos de ovários adquiridos em abatedouro, determinando o índice de recuperação dessas estruturas e identificando os de maior viabilidade para o procedimento de fertilização in vitro. Através da aspiração folicular, foram obtidos oócitos posteriormente classificados em escala de 1 a 4, de acordo com a quantidade de camadas de células do complexo cumulus oophorus que envolvem o oócito. Observouse 15,22% de oócitos de qualidade 1; 25,88% de qualidade 2; 35,53% de qualidade 3 e 23,35% de qualidade 4, determinando maiores índices de oócitos recuperados classificados na qualidade 2 e 3, sendo estes fisiologicamente viáveis e capacitados para entrarem em um programa de fertilização in vitro. Oócito. Bovino. Fecundação in vitro. summarY: The production of embryos in vitro is a biotechnology used, alternatively, to accelerate the production of genetically superior animals in addition to the deepening of knowledge concerning physiological processes, biochemical and biotechnological interest of the animal. The development of techniques in vitro to produce embryos of domestic animals has great potential both for basic research and for applications in the field and has been widely used and distributed in Brazil and abroad. This study aimed to classify bovine oocytes obtained from ovaries acquired in a slaughterhouse, determining the rate of recovery of these structures and identifying the most viable for the procedure for in vitro fertilization. Through follicular aspiration, oocytes were ranked in scale from 1 to 4, according to the amount of layers of cells in the complex cumulus oophorus involving the oocyte. There was 15.22% of high-quality oocytes 1; 25.88% of quality 2; 35.53% from 23.35% quality 3 and quality 4, setting higher rates of oocytes recovered classified as 2 and 3, which are physiologically viable and able to enter into a program of in vitro fertilization. palavras-chave:

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Manipulation of chromosome condensation by protein synthesis inhibitors and cyclic AMP during maturation of bovine oocytes

Cited by 12 publications

References 17 publications

Effect of microinjection time during postfertilization S‐phase on bovine embryonic development

Effect of microinjection time during postfertilization S‐phase on bovine embryonic development

Effects of cumulus cells and follicle‐stimulating hormone during in vitro maturation on parthenogenetic activation of bovine oocytes

Índice De Recuperação De Oócitos Bovinos Obtidos De Ovários Adquiridos Em Abatedouro Como Contribuição Para Os Estudos De Fecundação E Produção De Embriões in Vitro

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