Epigenetic modification with trichostatin A does not correct specific errors of somatic cell nuclear transfer at the transcriptomic level; highlighting the non-random nature of oocyte-mediated reprogramming errors

Pre- and post- implantation development. Effect of TSA treatment on in vitro and in vivo development of cloned embryos compared to fertilized counterparts. (DOCX 18 kb

Meta-analysis of gene expression profiles in granulosa cells during folliculogenesis

Folliculogenesis involves coordinated profound changes in different follicular compartments and significant modifications of their gene expression patterns, particularly in granulosa cells. Huge datasets have accumulated from the analyses of granulosa cell transcriptomic signatures in predefined physiological contexts using different technological platforms. However, no comprehensive overview of folliculogenesis is available. This would require integration of datasets from numerous individual studies. A prerequisite for such integration would be the use of comparable platforms and experimental conditions. The EmbryoGENE program was created to study bovine granulosa cell transcriptomics under different physiological conditions using the same platform. Based on the data thus generated so far, we present here an interactive web interface called GranulosaIMAGE (Integrative Meta-Analysis of Gene Expression), which provides dynamic expression profiles of any gene of interest and all isoforms thereof in granulosa cells at different stages of folliculogenesis. GranulosaIMAGE features two kinds of expression profiles: gene expression kinetics during bovine folliculogenesis from small (6 mm) to pre-ovulatory follicles under different hormonal and physiological conditions and expression profiles of granulosa cells of dominant follicles from post-partum cows in different metabolic states. This article provides selected examples of expression patterns along with suggestions for users to access and generate their own patterns using GranulosaIMAGE. The possibility of analysing gene expression dynamics during the late stages of folliculogenesis in a mono-ovulatory species such as bovine should provide a new and enriched perspective on ovarian physiology

Transcriptomic difference in bovine blastocysts following vitrification and slow freezing at morula stage.

Cryopreservation is known for its marked deleterious effects on embryonic health. Bovine compact morulae were vitrified or slow-frozen, and post-warm morulae were cultured to the expanded blastocyst stage. Blastocysts developed from vitrified and slow-frozen morulae were subjected to microarray analysis and compared with blastocysts developed from unfrozen control morulae for differential gene expression. Morula to blastocyst conversion rate was higher (P < 0.05) in control (72%) and vitrified (77%) than in slow-frozen (34%) morulae. Total 20 genes were upregulated and 44 genes were downregulated in blastocysts developed from vitrified morulae (fold change ≥ ± 2, P < 0.05) in comparison with blastocysts developed from control morulae. In blastocysts developed from slow-frozen morulae, 102 genes were upregulated and 63 genes were downregulated (fold change ≥ ± 1.5, P < 0.05). Blastocysts developed from vitrified morulae exhibited significant changes in gene expression mainly involving embryo implantation (PTGS2, CALB1), lipid peroxidation and reactive oxygen species generation (HSD3B1, AKR1B1, APOA1) and cell differentiation (KRT19, CLDN23). However, blastocysts developed from slow-frozen morulae showed changes in the expression of genes related to cell signaling (SPP1), cell structure and differentiation (DCLK2, JAM2 and VIM), and lipid metabolism (PLA2R1 and SMPD3). In silico comparison between blastocysts developed form vitrified and slow-frozen morulae revealed similar changes in gene expression as between blastocysts developed from vitrified and control morulae. In conclusion, blastocysts developed form vitrified morulae demonstrated better post-warming survival than blastocysts developed from slow-frozen morulae but their gene expression related to lipid metabolism, steroidogenesis, cell differentiation and placentation changed significantly (≥ 2 fold). Slow freezing method killed more morulae than vitrification but those which survived up to blastocyst stage did not express ≥ 2 fold change in their gene expression as compared with blastocysts from control morulae

Les bibliothèques au collégial : la nécessité d'une relance [dossier]

Bibliogr.Chaque article est disponible individuellement en format électronique: Les bibliothèques des cégeps québécois au tournant des années 2000 : une situation alarmante [résultats d'une étude couvrant les années 1976 à 1999] / L'interface humaine dans les services documentaires, une présence fragile à réinventer / Le nouveau rôle de la bibliothèque collégiale : priorité à l'étude et à l'apprentissage / RESDOC, la Bibliothèque virtuelle, bien réelle, des collèges du Québec [contribution du Réseau des services documentaires collégiaux à l'édification de la bibliothèque collégiale virtuelle] / Le Centre de documentation collégiale, partenaire du réseau collégial depuis près de trente ans! [les services offerts par ce centre qui a pour mandat de conserver tout ce qui se publie par et pour les cégeps]

Potential and limitations of bovine-specific arrays for the analysis of mRNA levels in early development: preliminary analysis using a bovine embryonic array.

New insights into the early development of large mammals are becoming available through the measurement of differential mRNA levels in oocytes and preimplantation embryos. These advances in knowledge are rapidly picking up in pace, mainly owing to the advantages brought by new molecular biology approaches being developed. The possibility of amplifying the starting material and therefore making measurements in single embryo units is now feasible. With these tools, the evaluation of variations in gene expression patterns during the preimplantation period or the impact of culture on mRNA levels is now possible. However, it is important to keep in mind that these methods still have limitations associated with sample preparation or the use of the appropriate controls. Even proper methods of analysis are very important to achieve the full benefit of the application of these tools. The present paper describes some of the potential, as well as limitations, of mRNA level analysis in early embryos, especially for microarray analysis. We have generated a bovine cDNA array (\u3e2000 clones) that contains expressed sequence tags (ESTs) collected from various preimplantation development stages. Using this chip, we have initiated the characterisation of global mRNA level patterns of several key developmental stages from the immature oocyte to the blastocyst stage. As expected, the hybridisation results indicate very different expression profiles involving hundreds of genes when comparing oocyte and blastocyst samples to a reference mRNA sample made from a pool of ESTs from pooled somatic tissues. Although this array is still in its preliminary stage and the EST bank has not been processed to contain only unigenes, it is already a very useful tool for discovering candidate genes that may play important roles during early embryonic life

Functional analysis of differential gene expression in IVP bovine embryos based on–log (<i>P</i>-value) obtained with Ingenuity^® Pathway Analysis software.

<p>Higher log values relate to higher significance of the functions. Top 10 cellular and molecular functions in each comparison are illustrated. Taller bars are more significant than shorter bars and the dotted line represents the cut-off value for <i>P</i> ≤ 0.05, -log-value = 1.3. Abbreviations: CON–control; SF–slow freezing; VIT–vitrification.</p