A Deus, pela saúde, proteção, coragem e força para trilhar este caminho.Aos meus pais, Geraldo e Suzana, pelo amor incondicional em todos os momentos da minha vida. Pelo apoio e incentivo para eu concluir mais essa etapa. Obrigada por não medirem esforços e sempre me ajudarem a conquistar os meus sonhos. Agradeço à minha irmã, Sabrina, pela companhia e amizade durante toda essa jornada.Ao meu orientador, Dr. Maurício Machaim Franco, pela oportunidade de aprender por meio dos seus ensinamentos. Obrigada pela paciência, confiança, orientação e amizade durante toda esta trajetória. E por contribuir para o meu crescimento pessoal e profissional, no qual você é um exemplo para mim.Ao meu namorado, Charles, pelo amor, compreensão e incentivo a todo momento.Aos amigos que fiz em Brasília e que fazem parte do Laboratório de Reprodução Animal (LRA), obrigada pelo convívio, momentos de descontração, amizade e apoio demonstrado. Em especial, a Luna e a Thainara, por tanta ajuda, pelo carinho, irmandade e todos os momentos que estavam ao meu lado. A amizade de todos vocês estará sempre em minha memória e coração.A Embrapa Recursos Genéticos e Biotecnologia, por proporcionar toda a estrutura e pelo auxílio financeiro para a realização deste trabalho.A Universidade Federal de Uberlândia e ao Programa de Pós-Graduação em Genética e Bioquímica pelo curso de mestrado ofertado, e a todos os professores que dele fazem parte. Um agradecimento especial à secretária do programa, Janaína de Souza Mota, pela disponibilidade e ajuda de sempre.A todos que contribuíram, direta ou indiretamente, para a realização deste trabalho, a minha sincera gratidão! SUMÁRIO

The establishment of epigenetic marks during the reprogramming window is susceptible to environmental influences, and stimuli during this critical stage can cause altered DNA methylation in offspring. In a previous study, we found that low levels of sulphur and cobalt (low S/Co) in the diet offered to oocyte donors altered the DNA methylome of bovine embryos. However, due to the extensive epigenetic reprogramming that occurs during embryogenesis, we hypothesized that the different methylation regions (DMRs) identified in the blastocysts may not maintain in adulthood. Here, we aimed to characterize DMRs previously identified in embryos, in the blood and sperm of adult progenies of two groups of heifers (low S/Co and control). We used six bulls and characterized the DNA methylation levels of KDM2A, KDM5A, KMT2D, and DOT1L genes. Our results showed that all DMRs analysed in both groups and tissues were hypermethylated unlike that noticed in the embryonic methylome profiles. These results suggest that embryo DMRs were reprogrammed during the final stages of de novo methylation during embryogenesis or later in development. Therefore, due to the highly dynamic epigenetic state during early embryonic development, we suggest that is essential to validate the DMRs found in embryos in adult individuals.

The aim of the present work was to assess the biological viability of two titanium surfaces treated by electric discharge machining (EDM) using water or hydroxyapatite as modifying agents and compare them to a machined titanium surface without modifying agent as a control. The in vitro MTT, total protein, alkaline phosphatase and alizarin red assays and scanning electron microscopy were applied to analyze pre-osteoblastic MC3T3-E1 cells after 7, 14 and 21 days of cell culture on the titanium surfaces. The results showed the presence of cellular activity in all surfaces and the formation of bone matrix, with no discrepancy among the groups. All tested surfaces were capable of inducing bone formation. In the topographic analysis of the surface, EDM failed to modify the surface of the discs homogeneously. Thus, EDM is a low-cost, biocompatible technique that favors osseointegration, but which still needs to be improved.

X chromosome inactivation (XCI) compensates for the imbalance in gene expression between sexes. In mice, it is well established that the long non-coding RNA (lncRNA) X-inactive specific transcript (XIST) is essential for initiating XCI. The most well-known antisense transcript of the mouse XIST locus is TSIX, a negative modulator of XIST. However, in cattle, these events are not yet well established. In this study, we characterized the patterns of strand-specific transcription along the XIST locus in bovine fetal placenta, since understanding the regulation of gene expression in the placenta and of the transcripts involved in XCI in order to minimize ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 21 (2): gmr19039 P.S. de Castro et al. 2embryonic and fetal losses due to the use of assisted reproduction techniques (ARTs) is key for livestock production. Sense transcription was detected throughout the XIST locus in male and female, and antisense transcription was detected in exon 1 of female fetal cotyledons. The sense transcripts may be lncRNA XIST, while the antisense transcript identified in exon 1 is not TSIX, but rather other uncharacterized RNAs. Moreover, our results show the relevance of taking into account the possibility of antisense expression for gene expression studies, especially in non-coding RNA or pseudogenes loci, where transcription from the two DNA strands is not rare. Taken together, the results show the importance of characterization as an aid to a better understanding of XCI in cattle, considering that epigenetic reprogramming can be impaired in cattle by the use of ARTs.