Universidades Brasileiras e seus Repositórios Institucionais

Caracterizados como meio de transmissão do conhecimento gerado, os repositórios institucionais cumprem seu papel na construção e existência de uma sociedade mais igualitária. Nesse sentido, por intermédio de pesquisa teórica aplicada, investigou-se se Instituições de Ensino Superior citadas pelo Webmetrics e CWUR possuíam repositórios que atendiam os padrões instituídos pelo Instituto Brasileiro de Informação em Ciência e Tecnologia. Como resultado da análise, constatou-se que essas instituições possuem repositórios e que eles estão de acordo com os critérios estabelecidos para sua constituição

Efeito do diâmetro folicular, momento da primeira clivagem e metilação da H3K4 na produção embrionária de vacas Bos indicus

This study aimed investigate the relationship between epigenetics, follicular diameter and cleavage speed, by evaluating the developmental potential and occurence of H3K4 monomethylation of early-, intermediate- and late-cleaving Bos indicus embryos from in vitro fertilized oocytes originating from follicles up to 2 mm in diameter or between 4 and 8 mm in diameter. Oocytes (n = 699) from small follicles (? 2 mm) and 639 oocytes from large follicles (4-8 mm) were punched from 1,982 Bos indicus’ slaughterhouse ovaries. After maturation and in vitro fertilization (IVF), the cultured embryos were separated into early (? 28 h post-IVF), intermediate (> 28 h and ? 34 h post-IVF) and late (> 34 h and ? 54 h post-IVF) cleavage groups. Blastocysts were subjected to an immunofluorescence assessment for H3K4me investigation. The blastocyst rate for large follicles (36.3%) was higher than that for small follicles (22.9%, P 28 h e ? 34 h pós-FIV) e tardia (> 34 h e ? 54 h pós-FIV). Os blastocistos foram submetidos à imunofluorescência para investigação de H3K4me. A taxa de blastocisto para embriões provenientes de folículos grandes (36,3%) foi maior que de folículos pequenos (22,9%; p < 0,05). Ainda, as taxas de blastocisto para os grupos de clivagem precoce e intermediária (45,3% e 33,8%, respectivamente) foram maiores que para o grupo de clivagem tardia (13,5%; p < 0,05). Blastocistos de todos os grupos mostraram marcação para H3K4me à imunofluorescência, particularmente intensa no que pareciam ser células do trofectoderma e fraca ou ausente em células semelhantes às da massa celular interna. Pela primeira vez em embriões indicus, os dados deste estudo demonstram que maiores taxas de blastocisto são obtidas de embriões que clivam em até 34 h pós-fertilização e dos oriundos de folículos de 4 a 8 mm de diâmetro, indicando uma maior habilidade desses embriões de se desenvolverem até o estágio de pré-implantação embrionária. Este é o primeiro artigo demonstrando a ocorrência de H3K4me em embriões bovinos; sua presença em todos os blastocistos avaliados sugere que essa modificação de histona exerce função-chave na manutenção da viabilidade embrionária no estágio pré-implantação

Developmental block and programmed cell death in Bos indicus embryos: effects of protein supplementation source and developmental kinetics.

The aims of this study were to determine if the protein source of the medium influences zebu embryo development and if developmental kinetics, developmental block and programmed cell death are related. The culture medium was supplemented with either fetal calf serum or bovine serum albumin. The embryos were classified as Fast (n = 1,235) or Slow (n = 485) based on the time required to reach the fourth cell cycle (48 h and 90 h post insemination - hpi -, respectively). The Slow group was further separated into two groups: those presenting exactly 4 cells at 48 hpi (Slow/4 cells) and those that reached the fourth cell cycle at 90 hpi (Slow). Blastocyst quality, DNA fragmentation, mitochondrial membrane potential and signs of apoptosis or necrosis were evaluated. The Slow group had higher incidence of developmental block than the Fast group. The embryos supplemented with fetal calf serum had lower quality. DNA fragmentation and mitochondrial membrane potential were absent in embryos at 48 hpi but present at 90 hpi. Early signs of apoptosis were more frequent in the Slow and Slow/4 cell groups than in the Fast group. We concluded that fetal calf serum reduces blastocyst development and quality, but the mechanism appears to be independent of DNA fragmentation. The apoptotic cells detected at 48 hpi reveal a possible mechanism of programmed cell death activation prior to genome activation. The apoptotic cells observed in the slow-developing embryos suggested a relationship between programmed cell death and embryonic developmental kinetics in zebu in vitro-produced embryos

Differential staining by fluorochrome.

<p>Epifluorescence photomicrography of the differential staining by fluorochrome of hatched blastocysts cultured with two sources of protein and classified according to the speed of development: A) Fast developing embryo cultured with BSA; B) Slow developing embryo cultured with BSA; C) Fast developing embryo cultured with FCS; and D) Slow developing embryo cultured with FCS.</p

Nuclei number in the ICM and TE from hatched blastocysts 9 days after IVF (Be—D9), supplemented with FCS, classified according to the speed of development (Fast or Slow).

<p>*—There were no significant differences between treatments (P ≤ 0.05).</p><p>Nuclei number in the ICM and TE from hatched blastocysts 9 days after IVF (Be—D9), supplemented with FCS, classified according to the speed of development (Fast or Slow).</p

TUNEL assay.

<p>Epifluorescence photomicrography of embryos at 48 and 90 hpi classified according to the speed of development as either Fast (reached the fourth cell cycle at 48 hpi) or Slow/4 cells (exactly 4 cells and prior to the fourth cell cycle at 48 hpi). A) Fast embryo at 48 h of culture; B) Slow/4 cell embryo at 48 h of culture; C) embryo at 48 h of culture submitted to DNA fragmentation via exposure to DNase (technique positive control); D) Fast embryo at 90 h of culture; E) Slow/4 cell embryo at 90 h of culture; and F) embryo at 90 h of culture submitted to DNA fragmentation via exposure to DNase. The blue fluorescent nuclei indicate total cell number and red fluorescent staining indicates cells with fragmented DNA.</p

Nuclei number in the ICM and TE from hatched blastocysts 9 days after IVF (Be—D9) classified according to the sources of protein (BSA or FCS).

<p>^{a, b}—Different letters in the same column indicate significant differences (P ≤ 0.05).</p><p>Nuclei number in the ICM and TE from hatched blastocysts 9 days after IVF (Be—D9) classified according to the sources of protein (BSA or FCS).</p

Comet assay.

<p>Epifluorescence photomicrography of the results for blastomeres isolated from embryos during the fourth cell cycle, which were classified according to the speed of development as either Fast developing (A) or Slow developing (B). The arrow indicates migrated DNA.</p

Annexin V staining.

<p>Epifluorescence photomicrography of embryos during the fourth cell cycle at 48 hpi: A) embryo with blastomeres undergoing apoptosis; B) blastomeres with blue staining indicating a positive reaction to the Annexin V antibody; and C) blastomeres without membrane permeability to propidium iodide.</p

Nuclei number in the ICM and TE from hatched blastocysts 9 days after IVF (Be—D9), supplemented with BSA, classified according to the speed of development (Fast or Slow).

<p>^a,b—Different letters in the same column indicate significant differences (P ≤ 0.05).</p><p>*—There were no significant differences between treatments (P ≤ 0.05).</p><p>Nuclei number in the ICM and TE from hatched blastocysts 9 days after IVF (Be—D9), supplemented with BSA, classified according to the speed of development (Fast or Slow).</p