Oocyte quality is one of the most important aspects of in vitro embryo development. Extensive epigenetic programming must occur during oocyte growth and maturation. A specific DNA methylation pattern of the imprinted genes must be established on differentially methylated regions (DMR). The insulin-like growth factor 2 (IGF2) gene is an important growth factor, and it is imprinted in several mammalian species. The aim of this study was to evaluate the methylation pattern on the DMR of the last exon of IGF2 in immature and mature bovine oocytes with different developmental competencies. Mature oocytes from large follicles were less methylated (28.93%) than immature oocytes from large follicles (77.38% P = 0.002), and there was also a tendency towards lower methylation in mature oocytes from large follicles (28.93%) compared with mature oocytes from small follicles (52.58% P = 0.07). Immature oocytes from small and large follicles showed 53.85% (7/13) and 91.66% (11/12) hypermethylated sequences, respectively, whereas mature oocytes from small and large follicles showed 61.11% (11/18) and 40% (4/10), respectively. The hypomethylation pattern in mature oocytes from large follicles may be related to the higher competence of these oocytes. Our results suggest that the methylation pattern in this DMR may be a useful parameter to investigate as a molecular marker for oocyte competence in cattle and as a model for studies in other species.

The objectives of this study were to investigate the effect of sexing by flow cytometry on the methylation patterns of the IGF2 and IGF2R genes. Frozen-thawed, unsorted, and sex-sorted sperm samples from four Nellore bulls were used. Each ejaculate was separated into three fractions: non-sexed (NS), sexed for X-sperm (SX), and sexed for Y-sperm (SY). Sperm were isolated from the extender, cryoprotectant, and other cell types by centrifugation on a 40:70% Percoll gradient, and sperm pellets were used for genomic DNA isolation. DNA was used for analyses of the methylation patterns by bisulfite sequencing. Methylation status of the IGF2 and IGF2R genes were evaluated by sequencing 195 and 147 individual clones, respectively. No global differences in DNA methylation were found between NS, SX, and SY groups for the IGF2 (P = 0.09) or IGF2R genes (P = 0.38). Very specific methylation patterns were observed in the 25th and 26th CpG sites in the IGF2R gene. representing higher methylation in NS than in the SX and SY groups compared with the other CpG sites. Further, individual variation in methylation patterns was found among bulls. In conclusion, the sex-sorting procedure by flow cytometry did not affect the overall DNA methylation patterns of the IGF2 and IGF2R genes, although individual variation in their methylation patterns among bulls was observed.

O artigo apresenta uma discussão sobre os processos de institucionalização e expansão do BRICS ao longo de suas nove cúpulas, destacando duas áreas temáticas: (i) economia política internacional – particularmente desenvolvimento internacional; e (ii) segurança internacional. A hipótese é a de que o BRICS vem passando por um processo de adensamento institucional, cuja maior expressão foi a criação do Novo Banco de Desenvolvimento (NBD) e do Arranjo Contingente de Reservas (ACR). Nesse processo, embora os temas de segurança internacional ganhem importância crescente, isso se deve às transformações na geopolítica do capitalismo contemporâneo. Além disso, há também um concomitante processo de outreach do BRICS. Nesse contexto, distintos padrões de adensamento institucional do arranjo podem ser notados. Concluiu-se que tanto o destaque das questões de segurança internacional quanto o processo de outreach com relação a outros países sofre uma influência direta do país que hospeda a cúpula. Ainda assim, o adensamento institucional ocorre em larga medida nas questões associadas à economia política internacional e, em particular, à questão do desenvolvimento internacional – uma espécie de “caminho de menor resistência” – embora não se deva perder de vista os avanços ocorridos nas últimas cúpulas nas questões de segurança internacional.

Este trabajo analiza las conductas político-económicas emprendidas por China posrreformas (1976-2015) a partir de la teoría y de la historia de los conceptos con base en Koselleck (2006) y Sartori (1970). La metodología fue cualitativa, enfocada en el análisis de contenido y en investigaciones bibliográfica y documental. Tal análisis sigue la evolución de los planos en el tiempo y su consecución vía planificación por medio de actos de habla y formalizados en políticas (policies). A partir de ahí, fue posible concluir que la innovación conceptual fue implementada de forma pragmática por la rpc (vía Partido Comunista Chino). Así, la rpc buscó el establecimiento de una relación amistosa entre Estado y mercado, inaugurando así un nuevo léxico en la economía política internacional contemporánea: la economía socialista de mercado.