8 research outputs found

    Efeitos da alta pressão gasosa sobre a viabilidade e expressão gênica de blastocistos expandidos bovinos produzidos in vitro submetidos à criopreservação

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    A alta pressão gasosa (HGP, do inglês high gaseous pressure) tem sido utilizada como agente indutor de estresse subletal, capaz de produzir uma resposta celular ao insulto e fornecer proteção a estresses subsequentes, para modificar a tolerância de gametas e embriões a procedimentos potencialmente prejudiciais, como a criopreservação. Este estudo teve como objetivo determinar o efeito da exposição à HGP de 27,6 MPa durante 2h sobre a sobrevivência de blastocistos expandidos bovinos produzidos in vitro frescos ou após o congelamento. Além disto, determinar o número total de células dos embriões criopreservados/descongelados eclodidos e o perfil transcricional dos genes CASP7 e NET1. No primeiro experimento, os embriões foram expostos à HGP e posteriormente submetidos ao cultivo in vitro por 72h. Não houve diferença nas taxas de eclosão dos blastocistos entre os grupos experimental (90,9% - 111/122) e controle (88,2% - 98/111). No segundo experimento, os embriões foram expostos à HGP, e 2h após o tratamento amostras de ambos os grupos foram fixadas para análise de expressão gênica, e os embriões remanescentes foram criopreservados pela curva de congelamento rápida. Duas horas após o descongelamento, uma segunda amostra foi fixada para análise da expressão de genes e o restante foi cultivado in vitro por 72h. A taxa de re-expansão dos embriões dos grupos controle e expostos à HGP, após 4 hrs, foram, respectivamente, 66,6% (92/138) e 74,6% (106/142). As taxas de eclosão (24h, 48h e 72h) pós-descongelamento dos embriões dos grupos controle e expostos à 27,6 MPa de HGP foram, respectivamente, 12,6% (15/119), 34,5% (41/119) e 52,1% (62/119), e, 12,2% (15/123), 35,8% (44/123) e 63,4% (78/123). Não foram observadas diferenças significativas na capacidade do blastocisto expandido de se reexpandir e eclodir entre os embriões dos grupos controle e submetidos à HGP. O número médio total de células dos blastocistos eclodidos do grupo HGP e do grupo controle também foram semelhantes as 24h (157,9 vs. 144,0), 48h (173,6 vs. 153,1) e 72h (190,6 vs. 162,6), respectivamente. Por outro lado, a determinação da expressão gênica revelou que 2h após a exposição à HGP e 2h após o descongelamento houve uma redução na expressão relativa do gene CASP7 e aumento da expressão relativa do gene NET1 nos embriões do grupo HGP. Nas condições em que os experimentos foram conduzidos, a exposição dos blastocistos expandidos à HGP não se caracterizou por maior sobrevivência embrionária após o descongelamento. No entanto, resultou em uma expressão alterada de genes que atuam sobre a cascata apoptótica (CASP7) e o crescimento e proliferação celular (NET1).High gaseous pressure (HGP) has been used as a sublethal stressor capable of inducing a cellular response to insult and providing protection to subsequent stresses in order, to modify the tolerance of gametes and embryos to potentially harmful procedures, such as cryopreservation. This study aimed to determine the effect of 27.6 MPa HGP exposure during 2h to of on the survival of bovine expanded blastocysts in vitro produced, fresh or after freezing. Moreover, determining the total number of cells from the cryopreserved/thawed embryos hatched and the transcriptional profile of CASP7 and NET1 genes. In the first experiment, the embryos were exposed to HGP and subsequently submitted to 72h of in vitro culture. There was no difference in the blastocyst hatch rates between the experimental (90.9% - 111/122) and control groups (88.2% - 98/111). In the second experiment, the embryos were exposed to HGP, and 2h after, samples of both groups were colected for gene expression analysis, and the remaining embryos were cryopreserved by the rapid freeze curve. After 2h of thawing, another sample was colected for analysis of gene expression and the remainder embryos were in vitro cultured during 72h. The re-expansion rates embryos of control and HGP exposed groups, after 4 hrs, were respectively 66.6% (92/138) and 74.6% (106/142). The post-thawing hatching rates (24h, 48h and 72h) of embryos of control and 27.6 MPa HGP exposed groups were respectively 12.6% (15/119), 34.5% (41/119) and 52.1% (62/119), and 12.2% (15/123), 35.8% (44/123) and 63.4% (78/123). No significant differences were observed in the ability of the expanded blastocyst to reexpand and hatch among of embryos of control and HGP exposed groups. The average of total number of cells in hatched blastocysts in the HGPand the control groups were also similar at 24h (157.9 vs. 144.0), 48h (173.6 vs. 153.1) and 72h (190.6 vs 162.6), respectively. On the other hand, determination of gene expression revealed that 2h after HGP exposure and 2h after thawing there were a reduction in the relative expression of CASP7 gene and increased the relative expression of NET1 gene in embryos of HGP group. Under our experimental conditions, the exposure of expanded blastocysts to the HGP was not characterized by improving embryo survival after thawing. However, it has resulted in modified expression of genes that act on apoptotic cascade (CASP7) and cell growth and proliferation (NET1)

    Efeitos da alta pressão gasosa sobre a viabilidade e expressão gênica de blastocistos expandidos bovinos produzidos in vitro submetidos à criopreservação

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    A alta pressão gasosa (HGP, do inglês high gaseous pressure) tem sido utilizada como agente indutor de estresse subletal, capaz de produzir uma resposta celular ao insulto e fornecer proteção a estresses subsequentes, para modificar a tolerância de gametas e embriões a procedimentos potencialmente prejudiciais, como a criopreservação. Este estudo teve como objetivo determinar o efeito da exposição à HGP de 27,6 MPa durante 2h sobre a sobrevivência de blastocistos expandidos bovinos produzidos in vitro frescos ou após o congelamento. Além disto, determinar o número total de células dos embriões criopreservados/descongelados eclodidos e o perfil transcricional dos genes CASP7 e NET1. No primeiro experimento, os embriões foram expostos à HGP e posteriormente submetidos ao cultivo in vitro por 72h. Não houve diferença nas taxas de eclosão dos blastocistos entre os grupos experimental (90,9% - 111/122) e controle (88,2% - 98/111). No segundo experimento, os embriões foram expostos à HGP, e 2h após o tratamento amostras de ambos os grupos foram fixadas para análise de expressão gênica, e os embriões remanescentes foram criopreservados pela curva de congelamento rápida. Duas horas após o descongelamento, uma segunda amostra foi fixada para análise da expressão de genes e o restante foi cultivado in vitro por 72h. A taxa de re-expansão dos embriões dos grupos controle e expostos à HGP, após 4 hrs, foram, respectivamente, 66,6% (92/138) e 74,6% (106/142). As taxas de eclosão (24h, 48h e 72h) pós-descongelamento dos embriões dos grupos controle e expostos à 27,6 MPa de HGP foram, respectivamente, 12,6% (15/119), 34,5% (41/119) e 52,1% (62/119), e, 12,2% (15/123), 35,8% (44/123) e 63,4% (78/123). Não foram observadas diferenças significativas na capacidade do blastocisto expandido de se reexpandir e eclodir entre os embriões dos grupos controle e submetidos à HGP. O número médio total de células dos blastocistos eclodidos do grupo HGP e do grupo controle também foram semelhantes as 24h (157,9 vs. 144,0), 48h (173,6 vs. 153,1) e 72h (190,6 vs. 162,6), respectivamente. Por outro lado, a determinação da expressão gênica revelou que 2h após a exposição à HGP e 2h após o descongelamento houve uma redução na expressão relativa do gene CASP7 e aumento da expressão relativa do gene NET1 nos embriões do grupo HGP. Nas condições em que os experimentos foram conduzidos, a exposição dos blastocistos expandidos à HGP não se caracterizou por maior sobrevivência embrionária após o descongelamento. No entanto, resultou em uma expressão alterada de genes que atuam sobre a cascata apoptótica (CASP7) e o crescimento e proliferação celular (NET1).High gaseous pressure (HGP) has been used as a sublethal stressor capable of inducing a cellular response to insult and providing protection to subsequent stresses in order, to modify the tolerance of gametes and embryos to potentially harmful procedures, such as cryopreservation. This study aimed to determine the effect of 27.6 MPa HGP exposure during 2h to of on the survival of bovine expanded blastocysts in vitro produced, fresh or after freezing. Moreover, determining the total number of cells from the cryopreserved/thawed embryos hatched and the transcriptional profile of CASP7 and NET1 genes. In the first experiment, the embryos were exposed to HGP and subsequently submitted to 72h of in vitro culture. There was no difference in the blastocyst hatch rates between the experimental (90.9% - 111/122) and control groups (88.2% - 98/111). In the second experiment, the embryos were exposed to HGP, and 2h after, samples of both groups were colected for gene expression analysis, and the remaining embryos were cryopreserved by the rapid freeze curve. After 2h of thawing, another sample was colected for analysis of gene expression and the remainder embryos were in vitro cultured during 72h. The re-expansion rates embryos of control and HGP exposed groups, after 4 hrs, were respectively 66.6% (92/138) and 74.6% (106/142). The post-thawing hatching rates (24h, 48h and 72h) of embryos of control and 27.6 MPa HGP exposed groups were respectively 12.6% (15/119), 34.5% (41/119) and 52.1% (62/119), and 12.2% (15/123), 35.8% (44/123) and 63.4% (78/123). No significant differences were observed in the ability of the expanded blastocyst to reexpand and hatch among of embryos of control and HGP exposed groups. The average of total number of cells in hatched blastocysts in the HGPand the control groups were also similar at 24h (157.9 vs. 144.0), 48h (173.6 vs. 153.1) and 72h (190.6 vs 162.6), respectively. On the other hand, determination of gene expression revealed that 2h after HGP exposure and 2h after thawing there were a reduction in the relative expression of CASP7 gene and increased the relative expression of NET1 gene in embryos of HGP group. Under our experimental conditions, the exposure of expanded blastocysts to the HGP was not characterized by improving embryo survival after thawing. However, it has resulted in modified expression of genes that act on apoptotic cascade (CASP7) and cell growth and proliferation (NET1)

    Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

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    International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora
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