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1.
Anim. Reprod. (Online) ; 20(2): e20230064, 2023.
Artigo em Inglês | VETINDEX | ID: biblio-1444264

Resumo

Genomic selection has transformed the livestock industry, enabling early-life selection of animals. Biopsy sampling of pre-implantation embryos has been described since 1968. However, it was only after 2010, with the advancement of molecular biology techniques such as whole genomic amplification and SNP Chips, that next-generation sequencing became commercially available for bovine embryos. It is now possible to make decisions about which embryos to transfer not only based on recipients' availability or embryo morphology but also on genomic estimates. This technology can be implemented for a wide spectrum of applications in livestock. In this review, we discuss the use of embryo biopsy for genomic selection and share our experience with Gir and Girolando Brazilian breeding programs, as well as future goals for implementing it in Brazilian bovine in vitro embryo production practices.(AU)


Assuntos
Animais , Feminino , Biópsia/veterinária , Bovinos/embriologia , Seleção Genética , Melhoramento Genético/métodos
2.
Anim. Reprod. (Online) ; 19(4): e20220108, 2022. tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1420057

Resumo

Cattle productivity in tropical and subtropical regions can be severely affected by the environment. Reproductive performance, milk and meat production are compromised by the heat stress imposed by the elevated temperature and humidity. The resulting low productivity contributes to reduce the farmer's income and to increase the methane emissions per unit of animal protein produced and the pressure on land usage. The introduction of highly productive European cattle breeds as well as crossbreeding with local breeds have been adopted as strategies to increase productivity but the positive effects have been limited by the low adaptation of European animals to hot climates and by the reduction of the heterosis effect in the following generations. Gene editing tools allow precise modifications in the animal genome and can be an ally to the cattle industry in tropical and subtropical regions. Alleles associated with production or heat tolerance can be shifted between breeds without the need of crossbreeding. Alongside assisted reproductive biotechnologies and genome selection, gene editing can accelerate the genetic gain of indigenous breeds such as zebu cattle. This review focuses on some of the potential applications of gene editing for cattle farming in tropical and subtropical regions, bringing aspects related to heat stress, milk yield, bull reproduction and methane emissions.(AU)


Assuntos
Animais , Masculino , Bovinos/embriologia , Transtornos de Estresse por Calor , Edição de Genes/tendências , Criação de Animais Domésticos/tendências
3.
Acta sci. vet. (Impr.) ; 39(2): 1-9, 20110000. ilus, tab
Artigo em Português | VETINDEX | ID: biblio-1456846

Resumo

Background: Embryonic stem cells are cells derived from early-stage embryos that are characterized by pluripotency and self- renewal capacity. The in vitro cultured murine embryonic stem cells can indefinitely propagate in an undifferentiated state in the presence of leukemia inhibitory factor (LIF). However, when stimulated, these cells can differentiate into cell lines derived from all three embryonic germ layers. The trichostatin A (TSA) is an epigenetic modifier agent and several studies have used the TSA to stimulate cellular differentiation. However, most of these studies only assessed one TSA concentration. Therefore, this study aimed to evaluate the effects of different TSA concentrations on histone hyperacetylation during in vitro cell differentiation of murine pluripotent embryonic stem cells, cultured with or without LIF, in the quest of to standardize their application on early cultures of embryonic stem cells. Materials, Methods & Results: Undifferentiated murine embryonic stem cells were plated in the presence of different TSA concentrations (0 nM, 15 nm, 50 nM and 100 nM) in the presence or absence of LIF. Thus, the treatments were evaluated in undifferentiated embryonic stem cells cultured in the presence of LIF (Control group: 0 nM LIF + ; Group 15 nM LIF + ; Group 50 nM LIF + and Group 100 nM LIF + ), and in embryonic stem cells cultured in the absence of LIF (Control group: 0 nM LIF - ; Group 15 nM LIF - ; Group 50 nM LIF - and Group 100 nM LIF - ). Treatment with TSA was performed for 24 h. After that the medium was replaced with fresh medium without TSA. Samples were collected at 0, 12, 24, 36 and 48 h after the beginning of the experiment. Three replicates were performed in each experimental group. The relative amount of Histone H3 lysine 9 acetylation was analyzed in all groups, as well as the cell proliferation in the embryonic stem cells cultured in the presence of LIF.


Assuntos
Acetilação , Células-Tronco Embrionárias , Diferenciação Celular , Histonas , Epigênese Genética
4.
Acta sci. vet. (Online) ; 39(2): 1-9, 20110000. ilus, tab
Artigo em Português | VETINDEX | ID: vti-11301

Resumo

Background: Embryonic stem cells are cells derived from early-stage embryos that are characterized by pluripotency and self- renewal capacity. The in vitro cultured murine embryonic stem cells can indefinitely propagate in an undifferentiated state in the presence of leukemia inhibitory factor (LIF). However, when stimulated, these cells can differentiate into cell lines derived from all three embryonic germ layers. The trichostatin A (TSA) is an epigenetic modifier agent and several studies have used the TSA to stimulate cellular differentiation. However, most of these studies only assessed one TSA concentration. Therefore, this study aimed to evaluate the effects of different TSA concentrations on histone hyperacetylation during in vitro cell differentiation of murine pluripotent embryonic stem cells, cultured with or without LIF, in the quest of to standardize their application on early cultures of embryonic stem cells. Materials, Methods & Results: Undifferentiated murine embryonic stem cells were plated in the presence of different TSA concentrations (0 nM, 15 nm, 50 nM and 100 nM) in the presence or absence of LIF. Thus, the treatments were evaluated in undifferentiated embryonic stem cells cultured in the presence of LIF (Control group: 0 nM LIF + ; Group 15 nM LIF + ; Group 50 nM LIF + and Group 100 nM LIF + ), and in embryonic stem cells cultured in the absence of LIF (Control group: 0 nM LIF - ; Group 15 nM LIF - ; Group 50 nM LIF - and Group 100 nM LIF - ). Treatment with TSA was performed for 24 h. After that the medium was replaced with fresh medium without TSA. Samples were collected at 0, 12, 24, 36 and 48 h after the beginning of the experiment. Three replicates were performed in each experimental group. The relative amount of Histone H3 lysine 9 acetylation was analyzed in all groups, as well as the cell proliferation in the embryonic stem cells cultured in the presence of LIF.(AU)


Assuntos
Histonas , Acetilação , Células-Tronco Embrionárias , Diferenciação Celular , Epigênese Genética
5.
Jaboticabal; s.n; 26/02/2010. 133 p.
Tese em Português | VETTESES | ID: vtt-3568

Resumo

Uma das etapas mais críticas do procedimento de transferência nuclear (TN) é a remoção da cromatina do oócito para a produção de citoplastos. O objetivo deste trabalho foi estudar o efeito de diferentes ambientes citoplasmáticos obtidos a partir de três técnicas de enucleação (convencional, assistida quimicamente e induzida quimicamente) sobre o remodelamento nuclear e desenvolvimento embrionário, avaliando-se o perfil de expressão dos genes XIST, G6PD e HSPA1A em embriões bovinos. Para isso, quatro experimentos foram delineados. No primeiro experimento, verificou-se que o processo de enucleação pode ser iniciado a partir de 1,0 h de tratamento com demecolcina nas duas técnicas de enucleação química. A dinâmica nuclear e de microtúbulos de oócitos ativados tratados com demecolcina foi avaliada em um segundo experimento, e oócitos tratados apresentaram redução da densidade dos microtúbulos, porém, essas estruturas não desapareceram completamente na maioria dos oócitos. No experimento III, a demecolcina não apresentou efeitos significativos na atividade do fator promotor de maturação (MPF) e da proteína cinase ativada por mitógeno (MAPK) quando utilizada na concentração 0,05?g/mL. No último experimento, a demecolcina não prejudicou o desenvolvimento embrionário e também não alterou o perfil de expressão dos genes XIST, G6PD e HSPA1A em embriões reconstituídos com células embrionárias; porém, quando foram avaliados os níveis de transcritos desses genes em embriões reconstituídos com células somáticas, observou-se maior expressão relativa do XIST e do G6PD em embriões oriundos da técnica de enucleação assistida quimicamente em comparação aos embriões produzidos pela técnica convencional. Portanto, conclui-se que a enucleação química não altera a reprogramação nuclear nem...


Removal of the oocyte chromatin for production of cytoplasts is one of the most critical steps of the standard nuclear transfer (NT) procedure. The aim of this work was to study the effect of different cytoplasmic environments from three enucleation techniques (conventional, chemical-assisted, and chemical-induced enucleation) on nuclear reprogramming and embryonic development, evaluating the expression patterns of XIST, G6PD and HSPA1A genes in bovine embryos. Therefore, four experiments were designed. In the first experiment, it was verified that the enucleation procedure can be initiated 1.0 h after starting demecolcine treatment on both chemical enucleation techniques. The nuclear and microtubular dynamics of activated oocytes treated with demecolcine were evaluated in a second experiment, and treated oocytes showed decreased microtubule density, but these structures did not completely disappear in most oocytes. In experiment III, demecolcine at a concentration of 0.05?g/mL had no significant effect on maturation promoting factor (MPF) and mitogen activated protein kinase (MAPK) activity. In the last experiment, demecolcine had no detrimental effects on embryonic development. Also, the expression patterns of XIST, G6PD and HSPA1A were not altered in reconstituted embryos derived from embryonic donor cells; however, evaluation of transcript levels of these genes in embryos reconstituted using somatic donor cells revealed higher relative expression of XIST and G6PD in embryos derived from chemicalassisted enucleation in comparison to embryos those produced by the conventional technique. In conclusion, chemical enucleation has no effect on nuclear reprogramming and embryonic development after nuclear transfer using embryonic donor cells. Also, chemical-assisted enucleation increases XIST and G6PD expression in nuclear transfer embryos...

6.
Jaboticabal; s.n; 20/02/2006. 93 p.
Tese em Português | VETTESES | ID: vtt-2714

Resumo

O objetivo desse estudo foi avaliar a ação da demecolcina na composição de microtúbulos, maturação e desenvolvimento in vitro de oócitos bovinos, submetidos ao tratamento em metáfase I (MI) e metáfase II (MII). No experimento I, observamos que a concentração 0,05æg/mL foi a mais eficaz na indução de enucleação no grupo MI (15,2%) e na formação de protrusão no grupo MII (55,1%). No experimento II, verificamos manifestações da demecolcina em apenas 0,5 h de tratamento, pelo aumento significativo de categorias de oócitos sem microtúbulos. Houve nova polimerização dessas estruturas, quando oócitos expostos à droga em MII, foram cultivados em meio livre desse agente. No experimento III, evidenciamos influência negativa da demecolcina na maturação nuclear de oócitos tratados em MI, durante 12 horas (4,9% de oócitos em MII) e um diferente comportamento quanto à distribuição de grânulos corticais (GC); enquanto no grupo MI houve tendência à antecipação na migração de GC para a periferia, após 2 horas de exposição à droga, no grupo MII, observou-se nesse momento, ação prejudicial da mesma. Ainda, verificamos incompleta expansão das células do cumulus em oócitos expostos à demecolcina por 12 horas. No experimento IV, obtivemos alta eficácia da técnica de enucleação (90,6%) e grande variação quanto ao desenvolvimento até o estádio de blastocisto (12,5 a 47%), não verificando-se ação prejudicial da droga no desenvolvimento embrionário


The aim of this study was to evaluate demecolcine action on microtubules composition, maturation and in vitro development of bovine oocytes, submitted to the treatment in metaphase I (MI) and metaphase II (MII). In the experiment I, we observed that 0.05æg/mL was the most efficient concentration to induce the enucleation in group MI (15.2%) and protrusion formation in group MII (55.1%). In experiment II, we verified demecolcine manifestations already after 0.5 hour of treatment, supported by the significant increase of categories of oocytes without microtubules. There was new polymerization of these structures when oocytes exposed to the drug in MII were cultured in agent-free medium. In experiment III, we evidenced negative influence of demecolcine on nuclear maturation of oocytes treated on MI for 12 hours (4.9% of oocytes in MII) and a different behavior for cortical granules (CG) distribution; while in MI group there was a tendency for the anticipation of CG migration to periphery, after 2 hours of drug exposition, in the MIII group, was observed a harmful effect of the drug. Moreover, we verified incomplete expansion of cumulus cells in oocytes exposed to demecolcine for 12 hours. In experiment IV, we got high effectiveness of enucleation technique (90.6%) and wide variation for development to the blastocyst stage (12.5 to 47%), and no harmful effects of the drug on embryonic development were observed

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