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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.
Anim. Reprod. (Online) ; 15(1): 71-74, Jan.-Mar. 2018. tab
Artigo em Inglês | VETINDEX | ID: biblio-1461340

Resumo

Holstein-Gyr crossbred cattle are strategic for dairy systems in tropical countries, since they combine milk yield genetics with adaptability to tropical climate. However, Holstein (Bos taurus) and Gyr (Bos indicus) breeds present remarkable differences regarding reproductive physiology. Brazil stands out as the world’s largest user of embryo in vitro production (IVP) in bovine, and the use of this technique is increasing in dairy systems. As Holstein-Gyr crossbreds are important oocyte donors for IVP, the present work aimed at investigating whether increased Gyr or Holstein breed composition influences donor’s performance. Sixteen Holstein-Gyr crossbred females presenting increased (HG, 71.4 to 87.5% Holstein; n = 9) or decreased (GH, 40.2 to 46.6% Holstein; n = 7) Holstein composition were submitted to three ovum pick up (OPU) sessions. We observed similar (P = 0.2946) antral follicle count between HG and GH donors (24.8 ± 3.2 vs 29.4 ± 2.8 respectively; mean ± SEM). Groups also display similar morphological oocyte grading (Grade I: 0.1 ± 0.1 vs 0.1 ± 0.1 – P = 0.9680; Grade II: 0.9 ± 0.5 vs 1.9 ± 0.5 – P = 0.1942; Grade III, 4.0 ± 1.2 vs 7.2 ± 1.4 – P = 0.1047, HG vs GH respectively; mean ± SEM). Additionally, the proportion of viable oocyte was similar between HG and GH groups (27.8% vs 31.9%, respectively, P = 0.3500) and oocyte lipid area fraction (6.8% vs 9.5%, respectively; P = 0.1539). Our results indicate that the individual variation has more influence than breed composition of crossbred oocyte donors.


Assuntos
Feminino , Animais , Bovinos , Bovinos/embriologia , Bovinos/metabolismo , Doação de Oócitos/veterinária , Ração Animal
4.
Anim. Reprod. ; 15(1): 71-74, Jan.-Mar. 2018. tab
Artigo em Inglês | VETINDEX | ID: vti-18924

Resumo

Holstein-Gyr crossbred cattle are strategic for dairy systems in tropical countries, since they combine milk yield genetics with adaptability to tropical climate. However, Holstein (Bos taurus) and Gyr (Bos indicus) breeds present remarkable differences regarding reproductive physiology. Brazil stands out as the worlds largest user of embryo in vitro production (IVP) in bovine, and the use of this technique is increasing in dairy systems. As Holstein-Gyr crossbreds are important oocyte donors for IVP, the present work aimed at investigating whether increased Gyr or Holstein breed composition influences donors performance. Sixteen Holstein-Gyr crossbred females presenting increased (HG, 71.4 to 87.5% Holstein; n = 9) or decreased (GH, 40.2 to 46.6% Holstein; n = 7) Holstein composition were submitted to three ovum pick up (OPU) sessions. We observed similar (P = 0.2946) antral follicle count between HG and GH donors (24.8 ± 3.2 vs 29.4 ± 2.8 respectively; mean ± SEM). Groups also display similar morphological oocyte grading (Grade I: 0.1 ± 0.1 vs 0.1 ± 0.1 P = 0.9680; Grade II: 0.9 ± 0.5 vs 1.9 ± 0.5 P = 0.1942; Grade III, 4.0 ± 1.2 vs 7.2 ± 1.4 P = 0.1047, HG vs GH respectively; mean ± SEM). Additionally, the proportion of viable oocyte was similar between HG and GH groups (27.8% vs 31.9%, respectively, P = 0.3500) and oocyte lipid area fraction (6.8% vs 9.5%, respectively; P = 0.1539). Our results indicate that the individual variation has more influence than breed composition of crossbred oocyte donors.(AU)


Assuntos
Animais , Feminino , Bovinos , Ração Animal , Doação de Oócitos/veterinária , Bovinos/embriologia , Bovinos/metabolismo
5.
Ciênc. rural (Online) ; 47(8): 1-4, 2017. tab
Artigo em Inglês | VETINDEX | ID: biblio-1480041

Resumo

ABSTRACT: For a long time, it has been stated that urine leptospiral shedding is intermittent, which was observed primarily by culturing. However, culturing presents serious limitations, mainly low sensitivity, and failure on detection of leptospires cannot be neglected. PCR presents several advantages, mainly higher sensitivity. The present study aimed to analyze the occurrence of intermittency on leptospiral shedding by PCR in naturally and experimentally infected animals. In this study two experiments were conducted, the first with 60 cows naturally infected from an endemic herd. The second one was conducted in three sheep experimentally infected, each one with a different strain of Leptospira (strains Copenhageni L1-130, Canicola LO-4 and Pomona Fromm). Considering cattle, 43.3% presented negative in all tests, the remaining (56.7%) were positive at least once. From these, only one (1.6%) was positive in all samples, and seven (11.8%) were positive only in the last sampling, making it impossible to evaluate the intermittency. Noteworthy, 26 cows (43.3%) presented the typical intermittent pattern of leptospiral shedding in urine. In sheep, all experimentally infected animals presented the typical intermittent shedding patterns, independently of the inoculated leptospiral strain. We considered that a careful serial analysis of urine samples for a more definitive and reliable individual diagnosis would be required for a successful antimicrobial therapy and control of leptospirosis on a herd.


RESUMO: Durante muito tempo, foi afirmado que a eliminação de leptospiras na urina era intermitente, o que havia sido demonstrado principalmente por meio do cultivo microbiano. No entanto, a cultura apresenta graves limitações, principalmente com relação à baixa sensibilidade. Em contraste, a PCR apresenta várias vantagens em relação ao cultivo bacteriológico para leptospiras, sendo esta ferramenta cada vez mais utilizada para o diagnóstico de animais eliminadores da bactéria em diversos sítios. Assim, o presente estudo teve como objetivo analisar a ocorrência de intermitência na eliminação de leptospiras por meio de PCR em animais natural e experimentalmente infectados. Para este estudo foram realizados dois experimentos, sendo o primeiro com 60 vacas naturalmente infectadas de um rebanho sabidamente endêmico e o segundo em três ovelhas experimentalmente infectadas, cada uma com uma estirpe diferente de Leptospira (estirpes Copenhageni L1-130, Canicola LO-4 e Pomona Fromm). Considerando-se os bovinos, 43,3% apresentaram negatividade em todos os testes, sendo os demais 56,7% positivos ao menos uma vez. Destes, apenas um (1,6%) foi positivo em todas as amostras, e sete (11,8%) foram positivos somente na última coleta, o que impossibilitou a avaliação da intermitência. Não obstante, 26 vacas naturalmente infectadas (43,3%) apresentaram o padrão de eliminação tipicamente intermitente de leptospiras na urina. Das três ovelhas experimentalmente infectadas, todas apresentaram eliminação intermitente da bactéria na urina, independentemente da estirpe inoculada. Consideramos que seria necessária uma cuidadosa análise seriada de amostras de urina para um diagnóstico individual mais definitivo e confiável para uma terapia antimicrobiana bem-sucedida e o controle da leptospirose em um rebanho.


Assuntos
Animais , Derrame de Bactérias , Doenças dos Ovinos/diagnóstico , Leptospira , Ovinos , Reação em Cadeia da Polimerase/métodos , Urina/microbiologia
6.
Ci. Rural ; 47(8): 1-4, 2017. tab
Artigo em Inglês | VETINDEX | ID: vti-735387

Resumo

ABSTRACT: For a long time, it has been stated that urine leptospiral shedding is intermittent, which was observed primarily by culturing. However, culturing presents serious limitations, mainly low sensitivity, and failure on detection of leptospires cannot be neglected. PCR presents several advantages, mainly higher sensitivity. The present study aimed to analyze the occurrence of intermittency on leptospiral shedding by PCR in naturally and experimentally infected animals. In this study two experiments were conducted, the first with 60 cows naturally infected from an endemic herd. The second one was conducted in three sheep experimentally infected, each one with a different strain of Leptospira (strains Copenhageni L1-130, Canicola LO-4 and Pomona Fromm). Considering cattle, 43.3% presented negative in all tests, the remaining (56.7%) were positive at least once. From these, only one (1.6%) was positive in all samples, and seven (11.8%) were positive only in the last sampling, making it impossible to evaluate the intermittency. Noteworthy, 26 cows (43.3%) presented the typical intermittent pattern of leptospiral shedding in urine. In sheep, all experimentally infected animals presented the typical intermittent shedding patterns, independently of the inoculated leptospiral strain. We considered that a careful serial analysis of urine samples for a more definitive and reliable individual diagnosis would be required for a successful antimicrobial therapy and control of leptospirosis on a herd.(AU)


RESUMO: Durante muito tempo, foi afirmado que a eliminação de leptospiras na urina era intermitente, o que havia sido demonstrado principalmente por meio do cultivo microbiano. No entanto, a cultura apresenta graves limitações, principalmente com relação à baixa sensibilidade. Em contraste, a PCR apresenta várias vantagens em relação ao cultivo bacteriológico para leptospiras, sendo esta ferramenta cada vez mais utilizada para o diagnóstico de animais eliminadores da bactéria em diversos sítios. Assim, o presente estudo teve como objetivo analisar a ocorrência de intermitência na eliminação de leptospiras por meio de PCR em animais natural e experimentalmente infectados. Para este estudo foram realizados dois experimentos, sendo o primeiro com 60 vacas naturalmente infectadas de um rebanho sabidamente endêmico e o segundo em três ovelhas experimentalmente infectadas, cada uma com uma estirpe diferente de Leptospira (estirpes Copenhageni L1-130, Canicola LO-4 e Pomona Fromm). Considerando-se os bovinos, 43,3% apresentaram negatividade em todos os testes, sendo os demais 56,7% positivos ao menos uma vez. Destes, apenas um (1,6%) foi positivo em todas as amostras, e sete (11,8%) foram positivos somente na última coleta, o que impossibilitou a avaliação da intermitência. Não obstante, 26 vacas naturalmente infectadas (43,3%) apresentaram o padrão de eliminação tipicamente intermitente de leptospiras na urina. Das três ovelhas experimentalmente infectadas, todas apresentaram eliminação intermitente da bactéria na urina, independentemente da estirpe inoculada. Consideramos que seria necessária uma cuidadosa análise seriada de amostras de urina para um diagnóstico individual mais definitivo e confiável para uma terapia antimicrobiana bem-sucedida e o controle da leptospirose em um rebanho.(AU)


Assuntos
Animais , Ovinos , Doenças dos Ovinos/diagnóstico , Leptospira , Derrame de Bactérias , Reação em Cadeia da Polimerase/métodos , Urina/microbiologia
7.
Braz. J. Vet. Res. Anim. Sci. (Online) ; 54(3): 264-276, 2017. tab
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-879464

Resumo

The aim of this work was to submit sperm cells to different laboratory challenges and to compare in vitro results with in vivo semen fertility. Four different batches from the same Brangus bull were used in a timed-AI program of 332 Brangus cows. Each batch (B) was submitted to the following procedure: semen sample was thawed at 36°C for 30 seconds (control). Sperm motility parameters, plasma membrane integrity, sperm morphology, and concentration were assessed. Then, an aliquot of thawed sample was incubated in a water bath at 45°C for 40 min (thermal challenge group; TCG) and another aliquot was centrifuged at 500 xg (Percoll gradient 45%/90%) for 15 min (centrifugation challenge group; CCG). Centrifuged semen was also submitted to another thermal challenge, being incubated (water bath) at 45°C for 40 min (centrifugation + thermal challenge group; CTCG). At the end of each challenge (CCG, TCG, and CTCG), the same laboratory tests used for control group were repeated. The following conception rates (CR) were observed for each batch: B1 = 48.9% (44/90); B2 = 44.2% (23/52); B3 = 55.5% (40/72); B4 = 43.2% (51/118); (p < 0.10). In the lab, B3 presented higher (p ≤ 0.05) progressive motility (PM) than B4 after thawing (control group) and after all sperm challenges (TCG, CCG, and CTCG). However, despite B3 and B4 having demonstrated a similar percentage of plasma membrane integrity (PMI) to the control group (B3 = 66.7 ± 1.3 and B4 = 65.2 ± 3.3), B3 demonstrated higher (P ≤ 0.05) percentage of PMI (37.2 ± 2.5) than B4 (26.7 ± 3.3) after passing through the most stressing in vitro challenge (CTCG). The semen batch presenting the highest resistance to in vitro challenges was the one that presented a trend for higher in vivo fertility, suggesting that submitting semen samples to laboratory challenges may be an interesting alternative for selecting batches with greater field fertility.(AU)


O objetivo deste estudo foi estressar células espermáticas em diferentes desafios laboratoriais e comparar os resultados in vitro com a fertilidade in vivo do sêmen. Quatro partidas de um mesmo touro Brangus foram utilizadas em um programa de IATF de 332 vacas Brangus. Cada partida foi submetida ao seguinte procedimento: a amostra de sêmen foi descongelada a 36°C por 30 segundos (grupo controle). Foram avaliados parâmetros de motilidade espermática (CASA), integridade da membrana plasmática (PMI), morfologia e concentração espermática. Em seguida, uma alíquota da amostra descongelada foi incubada em banho-maria a 45°C durante 40 minutos (grupo de desafio térmico, TCG) e outra alíquota foi centrifugada a 500 xg (gradiente de Percoll 45%/90%) durante 15 min (grupo desafio de centrifugação, CCG). Uma aliquota do sêmen centrifugado foi ainda submetida ao desafio térmico, sendo incubado a 45°C durante 40 min (grupo de desafio térmico + centrifugação, CTCG). No final de cada desafio (CCG, TCG e CTCG), os mesmos testes laboratoriais utilizados para o grupo de controle foram realizados. A seguinte taxa de concepção (CR) foi observada para cada partida (B): B1 = 48,9% (44/90), B2 = 44,2% (23/52), B3 = 55,5% (40/72) e B4 = 43,2% (51/118); (P < 0,10). No laboratório, B3 apresentou maior (P ≤ 0,05) motilidade progressiva (PM) do que B4 logo após o descongelamento (grupo controle) e após todos os desafios laboratoriais (TCG, CCG e CTCG). Porém, apesar de B3 e B4 demonstrarem similar porcentagem de PMI no grupo controle (B3 = 66,7 ± 1,3 e B4 = 65,2 ± 3,3), B3 apresentou maior (P ≤ 0,05) PMI (37,2 ± 2,5%) do que B4 (26,7 ± 3,3%) após passar pelo maior desafio laboratorial (CTCG). A partida seminal que in vitro apresentou maior resistência aos desafios laboratoriais foi a mesma que apresentou tendência para maior fertilidade in vivo. Assim, sugere-se que submeter amostras seminais a desafios laboratoriais pode ser uma alternativa interessante para selecionar partidas com maior fertilidade a campo.(AU)


Assuntos
Animais , Bovinos , Fertilização in vitro/veterinária , Inseminação Artificial/veterinária , Técnicas de Reprodução Assistida/veterinária , Preservação do Sêmen/efeitos adversos
8.
Braz. j. vet. res. anim. sci ; 54(3): 264-276, 2017. tab
Artigo em Inglês | VETINDEX | ID: vti-17959

Resumo

The aim of this work was to submit sperm cells to different laboratory challenges and to compare in vitro results with in vivo semen fertility. Four different batches from the same Brangus bull were used in a timed-AI program of 332 Brangus cows. Each batch (B) was submitted to the following procedure: semen sample was thawed at 36°C for 30 seconds (control). Sperm motility parameters, plasma membrane integrity, sperm morphology, and concentration were assessed. Then, an aliquot of thawed sample was incubated in a water bath at 45°C for 40 min (thermal challenge group; TCG) and another aliquot was centrifuged at 500 xg (Percoll gradient 45%/90%) for 15 min (centrifugation challenge group; CCG). Centrifuged semen was also submitted to another thermal challenge, being incubated (water bath) at 45°C for 40 min (centrifugation + thermal challenge group; CTCG). At the end of each challenge (CCG, TCG, and CTCG), the same laboratory tests used for control group were repeated. The following conception rates (CR) were observed for each batch: B1 = 48.9% (44/90); B2 = 44.2% (23/52); B3 = 55.5% (40/72); B4 = 43.2% (51/118); (p < 0.10). In the lab, B3 presented higher (p ≤ 0.05) progressive motility (PM) than B4 after thawing (control group) and after all sperm challenges (TCG, CCG, and CTCG). However, despite B3 and B4 having demonstrated a similar percentage of plasma membrane integrity (PMI) to the control group (B3 = 66.7 ± 1.3 and B4 = 65.2 ± 3.3), B3 demonstrated higher (P ≤ 0.05) percentage of PMI (37.2 ± 2.5) than B4 (26.7 ± 3.3) after passing through the most stressing in vitro challenge (CTCG). The semen batch presenting the highest resistance to in vitro challenges was the one that presented a trend for higher in vivo fertility, suggesting that submitting semen samples to laboratory challenges may be an interesting alternative for selecting batches with greater field fertility.(AU)


O objetivo deste estudo foi estressar células espermáticas em diferentes desafios laboratoriais e comparar os resultados in vitro com a fertilidade in vivo do sêmen. Quatro partidas de um mesmo touro Brangus foram utilizadas em um programa de IATF de 332 vacas Brangus. Cada partida foi submetida ao seguinte procedimento: a amostra de sêmen foi descongelada a 36°C por 30 segundos (grupo controle). Foram avaliados parâmetros de motilidade espermática (CASA), integridade da membrana plasmática (PMI), morfologia e concentração espermática. Em seguida, uma alíquota da amostra descongelada foi incubada em banho-maria a 45°C durante 40 minutos (grupo de desafio térmico, TCG) e outra alíquota foi centrifugada a 500 xg (gradiente de Percoll 45%/90%) durante 15 min (grupo desafio de centrifugação, CCG). Uma aliquota do sêmen centrifugado foi ainda submetida ao desafio térmico, sendo incubado a 45°C durante 40 min (grupo de desafio térmico + centrifugação, CTCG). No final de cada desafio (CCG, TCG e CTCG), os mesmos testes laboratoriais utilizados para o grupo de controle foram realizados. A seguinte taxa de concepção (CR) foi observada para cada partida (B): B1 = 48,9% (44/90), B2 = 44,2% (23/52), B3 = 55,5% (40/72) e B4 = 43,2% (51/118); (P < 0,10). No laboratório, B3 apresentou maior (P ≤ 0,05) motilidade progressiva (PM) do que B4 logo após o descongelamento (grupo controle) e após todos os desafios laboratoriais (TCG, CCG e CTCG). Porém, apesar de B3 e B4 demonstrarem similar porcentagem de PMI no grupo controle (B3 = 66,7 ± 1,3 e B4 = 65,2 ± 3,3), B3 apresentou maior (P ≤ 0,05) PMI (37,2 ± 2,5%) do que B4 (26,7 ± 3,3%) após passar pelo maior desafio laboratorial (CTCG). A partida seminal que in vitro apresentou maior resistência aos desafios laboratoriais foi a mesma que apresentou tendência para maior fertilidade in vivo. Assim, sugere-se que submeter amostras seminais a desafios laboratoriais pode ser uma alternativa interessante para selecionar partidas com maior fertilidade a campo.(AU)


Assuntos
Animais , Bovinos , Inseminação Artificial/veterinária , Fertilização in vitro/veterinária , Técnicas de Reprodução Assistida/veterinária , Preservação do Sêmen/efeitos adversos
9.
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
10.
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
11.
Acta sci. vet. (Impr.) ; 39(1): 01-08, 2011. tab
Artigo em Português | VETINDEX | ID: biblio-1456836

Resumo

Bull fertility is extremely important for beef cattle production systems and has a multiplier impact on the economical and zootechnical indexes of the herd. Bulls raised in tropical conditions may present varied seminal characteristics due to, among other causes, different management practices and quality of pastures. Another factor that influences the semen characteristics is the age of the sire. The reproductive potential of bull evaluated through the andrological exam aims to ensure the semen quality and to improve the herd reproductive efficiency. The aim of this study was to evaluate the main semen parameters of Brangus- Ibagé bulls extensively reared in eastern Mato Grosso do Sul state and to verify the effect of age on the andrological characteristics analyzed. It was also evaluated the correlation between age, scrotal circumference, and physical and morphological sperm characteristics produced by the Brangus bulls.[...]


Assuntos
Animais , Bovinos/classificação , Fatores Etários , Andrologia/tendências , Sêmen/citologia
12.
Acta sci. vet. (Impr.) ; 39(2): 1-4, 20110000. tab
Artigo em Inglês | VETINDEX | ID: biblio-1456852

Resumo

Background: In bovines, more efficient management practices are important for maximizing profitability. In order to increase the pregnancy rates in artificial insemination (AI) programs, several hormonal protocols were developed to synchronize the follicular wave and the moment of ovulation in beef and dairy cattle. In dairy cattle, detection of estrus can be difficult due to a number of factors including the incidence of silent estrus. Hormonal treatments designed to control both luteal and follicular function has permitting efficient synchronizations of time of ovulation. Thus, the AI can be performed in a large number of animals on a fixed schedule without the need for detection of estrus. Using these management techniques, the fixed-time artificial insemination (TAI) can overcome the problem of accurate estrus detection and help in reducing the incidence of repeat breeding. In addition, with TAI in cattle operations, it is possible to facilitate management practices and commercialization, and to reduce the time and semen wasting with animals inseminated at incorrect times. The investigation of practical and efficient TAI protocols is important for reducing the labor and animal handling of TAI in dairy cattle, as well as for increasing the profitability of the cattle management system. This study was carried out in order to investigate the effectiveness of TAI in dairy heifers treated with a practical progesterone-based protocol. Materials, Methods & Results: This experiment was conducted at the university farm located in southwestern Brazil, during May 2009. Thirty-nine cycling crossbred dairy heifers were employed in this study. All animals received a single intramuscular injection of estradiol benzoate and intravaginal progesterone releasing device in a random stage of the estrous cycle (Day 0). On day 7 the animals were treated with PGF2á analogue and on day 9 the device was removed. [...]


Assuntos
Feminino , Animais , Gravidez , Bovinos , Fertilização in vitro/veterinária , Inseminação Artificial/veterinária , Progesterona/administração & dosagem , Prenhez/fisiologia
13.
Acta sci. vet. (Online) ; 39(2): 1-4, 20110000. tab
Artigo em Inglês | VETINDEX | ID: vti-11307

Resumo

Background: In bovines, more efficient management practices are important for maximizing profitability. In order to increase the pregnancy rates in artificial insemination (AI) programs, several hormonal protocols were developed to synchronize the follicular wave and the moment of ovulation in beef and dairy cattle. In dairy cattle, detection of estrus can be difficult due to a number of factors including the incidence of silent estrus. Hormonal treatments designed to control both luteal and follicular function has permitting efficient synchronizations of time of ovulation. Thus, the AI can be performed in a large number of animals on a fixed schedule without the need for detection of estrus. Using these management techniques, the fixed-time artificial insemination (TAI) can overcome the problem of accurate estrus detection and help in reducing the incidence of repeat breeding. In addition, with TAI in cattle operations, it is possible to facilitate management practices and commercialization, and to reduce the time and semen wasting with animals inseminated at incorrect times. The investigation of practical and efficient TAI protocols is important for reducing the labor and animal handling of TAI in dairy cattle, as well as for increasing the profitability of the cattle management system. This study was carried out in order to investigate the effectiveness of TAI in dairy heifers treated with a practical progesterone-based protocol. Materials, Methods & Results: This experiment was conducted at the university farm located in southwestern Brazil, during May 2009. Thirty-nine cycling crossbred dairy heifers were employed in this study. All animals received a single intramuscular injection of estradiol benzoate and intravaginal progesterone releasing device in a random stage of the estrous cycle (Day 0). On day 7 the animals were treated with PGF2á analogue and on day 9 the device was removed. [...](AU)


Assuntos
Animais , Feminino , Gravidez , Bovinos , Fertilização in vitro/veterinária , Progesterona/administração & dosagem , Inseminação Artificial/veterinária , Prenhez/fisiologia
14.
Acta sci. vet. (Online) ; 39(1): 01-08, 2011. tab
Artigo em Português | VETINDEX | ID: vti-381304

Resumo

Bull fertility is extremely important for beef cattle production systems and has a multiplier impact on the economical and zootechnical indexes of the herd. Bulls raised in tropical conditions may present varied seminal characteristics due to, among other causes, different management practices and quality of pastures. Another factor that influences the semen characteristics is the age of the sire. The reproductive potential of bull evaluated through the andrological exam aims to ensure the semen quality and to improve the herd reproductive efficiency. The aim of this study was to evaluate the main semen parameters of Brangus- Ibagé bulls extensively reared in eastern Mato Grosso do Sul state and to verify the effect of age on the andrological characteristics analyzed. It was also evaluated the correlation between age, scrotal circumference, and physical and morphological sperm characteristics produced by the Brangus bulls.[...](AU)


Assuntos
Animais , Fatores Etários , Bovinos/classificação , Andrologia/tendências , Sêmen/citologia
15.
Jaboticabal,; s.n; 06/07/2012. 117 p.
Tese em Português | VETTESES | ID: vtt-1738

Resumo

Modificações pós-translacionais de histonas são importantes componentes do código epigenético, e contribuem para o controle da transcrição gênica de cada célula. O presente trabalho descreve a participação de duas modificações de histonas no desenvolvimento embrionário pré-implantacional: a acetilação de lisinas e a citrulinização de argininas. No capítulo 1, avaliamos a presença de duas modificações de histona H3, K9ac (permissiva) e K27me3 (repressiva) em embriões bovinos no ciclo de ativação do genoma embrionário (AGE), por imunofluorescência. Ambas as marcas estão presentes e apresentam alto coeficiente de correlação, e dois perfis de embriões (com alta e baixa variação dos níveis das modificações entre blastômeros) foram descritos. A acetilação de histonas está relacionada à ativação da expressão gênica, portanto no capítulo 2 hipotetizamos que a manipulação de seus níveis em embriões bovinos poderia influenciar a ativação do genoma embrionário, o desenvolvimento de blastocistos e a inativação do cromossomo X em fêmeas. Foram testadas concentrações do inibidor das histona desacetilases tricostatina A variando de 5 a 50nM, aplicadas por 12 a 144h, iniciando 70h após a FIV. Três protocolos foram selecionados: 5nM 48h, 5nM 144h e 15nM 48h. Após, foi utilizado sêmen sexado para estudar os efeitos da TSA sobre embriões fêmeas e machos separadamente. Por imunofluorescência para H3K9ac, foi observado aumento na acetilação de histonas em ambas as concentrações (5 e 15nM), sendo 5nM mais eficaz em fêmeas do que machos. O tratamento com 15nM 48h reduziu a produção de blastocistos em machos e fêmeas, e 5nM 144h em machos. A taxa de apoptose, avaliada pelo ensaio TUNEL, foi elevada em embriões fêmeas (grupos 5nM144h e 15nM48h), e em machos (grupo 15nM48h), mas tal aumento...


Histone post translational modifications are important components of the epigenetic code, and contribute to the control of gene transcription in each cell. This work describes the participation of two histone modifications in embryonic preimplantation development: acetylation of lysines and citrullination of arginines. In chapter 1, we evaluated the presence of two modifications of histone H3, K9ac (permissive) and K27me3 (repressive) in bovine embryos in the cycle of embryonic genome activation (EGA), by immunofluorescence. Both marks are present and show a high correlation coefficient, and two profiles of embryos were described, displaying high and low variation of modifications level between blastomeres. The acetylation of histones is related to gene expression activation, so in Chapter 2 we hypothesized that the manipulation of acetylation levels in bovine embryos could influence embryonic genome activation, blastocyst development and X chromosome inactivation in females. Five concentrations of the histone deacetylase inhibitor trichostatin A (TSA), ranging from 5 to 50nM beginning 70 hours after FIV were applied per 12 to 144h. Three protocols were selected: 5nM 48h, 5nM 144h and 15nm 48h. After, sexed semen was used to study the effects of TSA on male and female embryos separately. Immunofluorescence of H3K9ac showed increased histone acetylation at both concentrations (5 and 15nM). 5nM TSA was more effective in females than in males. Treatment with 15nM 48h reduced male and female blastocyst yield, and 5nM 144h reduced male blastocyst yield. Apoptosis rate was measured by the TUNEL assay. Female 5nM144h and 15nM48h groups, and male 15nM48h group displayed higher apoptosis levels, but this increase was not observed in low quality embryos. In female embryos, TSA did not affect...

16.
Jaboticabal; s.n; 19/02/2009. 107 p.
Tese em Português | VETTESES | ID: vtt-4645

Resumo

O estudo dos processos de diferenciação em células tronco embrionárias (CTE) representa uma importante ferramenta para o entendimento das vias moleculares que os regem, apresentando grande aplicação tanto na ciência básica quanto na engenharia de tecidos e medicina regenerativa. Pouco é conhecido sobre as marcas epigenéticas existentes na cromatina destas células, e de que forma a regulação da expressão gênica ocorre no momento da diferenciação. O presente trabalho teve como objetivo o estudo dos efeitos da hiperacetilação das histonas causada pela droga tricostatina A (TSA), uma inibidora das enzimas histona desacetilases, sobre a diferenciação destas células em estádios iniciais e avançados. Para tanto, a hiperacetilação induzida pela droga foi estimada por reações de imunocitoquímica para AcLys9H3. Os efeitos anti-proliferativos da TSA foram mensurados pelo teste de TUNEL e contagem de células. Ainda, foram conduzidos experimentos de diferenciação in vitro de CTE e análise da expressão de proteínas características de linhagens celulares diferenciadas por reações de imunocitoquímica (Oct3/4, nestina, âIII tubulina, desmina e troponina I), em cultivos tratados com TSA em diferentes concentrações e em diferentes momentos. Desta forma, foi estimada a população de tipos celulares oriundos dos folhetos embrionários ectodérmico e mesodérmico, como neurônios, e células musculares, quando foi promovida a hiperacetilação das histonas nas CTE, em diferentes momentos da diferenciação celular in vitro. A TSA induziu apoptose em níveis superiores aos do grupo controle, e retardou/inibiu a divisão celular. Promoveu hiperacetilação dose-dependente nos períodos estudados, e estimulou a diferenciação de precursores mesodérmicos (50nM d5) e ectodérmicos (15nMd0-5 e 50nMd5), cardiomiócitos (50nMd5 e 100nMd13) e neurônios (15nMd0-5, 50nMd5, 100nMd5, 100nMd13)


Studies on embryonic stem cells (ESC) differentiation represents an important tool leading to understanding of its molecular pathways, with many applications both on basic research and tissue engineering / regenerative medicine. Little is known about epigenetic marks on ESC chromatin, and how gene expression occurs at differentiation time. The aim of this work was to study effects of histone hiperacetylation, induced by cell treatment with trichostatin A (TSA), an histone deacetylase inhibitor, on both initial and late differentiation. For that, drug-induced hyperacetylation was studied by AcLys9H3 immunocitochemistry. TSA anti-proliferative effects were analysed by TUNEL test and cell counts. Experiments on ESC in vitro differentiation and immunocitochemistry for specific cell types proteins (Oct3/4, nestin, âIII tubulin, desmin and troponin I) were performed, in treated and control groups, at different moments. This analysis showed specific cell types populations derived from embryonic ectodermal and mesodermal, such as neurons and cardiomyocytes, when histone hyperacetylation were induced, on both initial and late diferentiation. Our results showed that TSA induces apoptosis and inhibits cellular proliferation. Also, TSA promoted dose-dependent histone hyperacetylation at studied moments, and stimulated mesodermal (50nM d5) and ectodermal (15nMd0-5 e 50nMd5) precursors, cardiomyocytes (50nMd5 e 100nMd13) and neurons (15nMd0-5, 50nMd5, 100nMd5, 100nMd13) differentiation

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