Search for the genes involved in oocyte maturation and early embryo development in the hen

<p>Abstract</p> <p>Background</p> <p>The initial stages of development depend on mRNA and proteins accumulated in the oocyte, and during these stages, certain genes are essential for fertilization, first cleavage and embryonic genome activation. The aim of this study was first to search for avian oocyte-specific genes using an <it>in silico </it>and a microarray approaches, then to investigate the temporal and spatial dynamics of the expression of some of these genes during follicular maturation and early embryogenesis.</p> <p>Results</p> <p>The <it>in silico </it>approach allowed us to identify 18 chicken homologs of mouse potential oocyte genes found by digital differential display. Using the chicken Affymetrix microarray, we identified 461 genes overexpressed in granulosa cells (GCs) and 250 genes overexpressed in the germinal disc (GD) of the hen oocyte. Six genes were identified using both <it>in silico </it>and microarray approaches. Based on GO annotations, GC and GD genes were differentially involved in biological processes, reflecting different physiological destinations of these two cell layers. Finally we studied the spatial and temporal dynamics of the expression of 21 chicken genes. According to their expression patterns all these genes are involved in different stages of final follicular maturation and/or early embryogenesis in the chicken. Among them, 8 genes (<it>btg4</it>, <it>chkmos</it>, <it>wee</it>, <it>zpA</it>, <it>dazL</it>, <it>cvh</it>, <it>zar1 </it>and <it>ktfn) </it>were preferentially expressed in the maturing occyte and <it>cvh</it>, <it>zar1 </it>and <it>ktfn </it>were also highly expressed in the early embryo.</p> <p>Conclusion</p> <p>We showed that <it>in silico </it>and Affymetrix microarray approaches were relevant and complementary in order to find new avian genes potentially involved in oocyte maturation and/or early embryo development, and allowed the discovery of new potential chicken mature oocyte and chicken granulosa cell markers for future studies. Moreover, detailed study of the expression of some of these genes revealed promising candidates for maternal effect genes in the chicken. Finally, the finding concerning the different state of rRNA compared to that of mRNA during the postovulatory period shed light on some mechanisms through which oocyte to embryo transition occurs in the hen.</p

Interactions between sperm packaging, gas environment, temperature and diluent on fresh stallion sperm survival

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Interactions between sperm packaging, gas environment, temperature and diluent on fresh stallion sperm survival

International audienc

Interactions between sperm packaging, gas environment, temperature and diluent on fresh stallion sperm survival

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Impact de protéines d'origine végétale, exprimées dans des plantes transgéniques, sur des insectes pollinisateurs et auxiliaires

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Des avancées sur les techniques de cryopréservation de la semence et sur son utilisation en insémination animale

Lettre de la Cryobanque NationaleDes avancées sur les techniques de cryopréservation de la semence et sur son utilisation en insémination animal

La semence congelee d'etalon : donnees experimentales et de terrain

National audienc

Effects of exposing chicken eggs to a cell phone in "call" position over the entire incubation period

International audienceThe aim of the present study was to assess the effects of exposing fertile chicken eggs to a cell phone repeatedly calling a ten-digit number at 3-min intervals over the entire period of incubation. A pre-experiment was performed first to adjust incubation conditions in an experimental chamber devoid of metallic content and without automatic turning until the overall performance of hatchability was reproducible in the absence of the cell phone. The experimental period consisted of a series of 4 incubations referred to as "replicates". For each replicate, one batch of 60 eggs was exposed to the immediate environment (<= 25 cm) of a cell phone in the "call" position (exposed group), while another batch of 60 eggs, 1.5 m away from the exposed group and also in the incubation chamber, was exposed to a similar cell phone in the "off " position (sham group). For each replicate, 2 other groups each of 60 eggs were also incubated, one in a standard mini-incubator ("Control I" group) and the second in a standard medium size incubator ("Control II" group). Temperature, relative humidity and electromagnetic fields in the experimental chamber were permanently monitored over the entire experiment. A significantly higher percentage of embryo mortality was observed in the "exposed" compared to the "sham" group in 2 of the 4 replicates (p < .05). In comparison with control groups, additional embryo mortality in the exposed group occurred mainly between Days 9 and 12 of incubation but a causal relationship between the intensity of the electric field and embryo mortality could not be established. <= 2008 Elsevier Inc. All rights reserved

Gene expression profiling reveals new potential players of gonad differentiation in the chicken embryo

Background : In birds as in mammals, a genetic switch determines whether the undifferentiated gonad develops into an ovary or a testis. However, understanding of the molecular pathway(s) involved in gonad differentiation is still incomplete. Methodology/Principal Findings : With the aim of improving characterization of the molecular pathway(s) involved in gonad differentiation in the chicken embryo, we developed a large scale real time reverse transcription polymerase chain reaction approach on 110 selected genes for evaluation of their expression profiles during chicken gonad differentiation between days 5.5 and 19 of incubation. Hierarchical clustering analysis of the resulting datasets discriminated gene clusters expressed preferentially in the ovary or the testis, and/or at early or later periods of embryonic gonad development. Fitting a linear model and testing the comparisons of interest allowed the identification of new potential actors of gonad differentiation, such as Z-linked ADAMTS12, LOC427192 (corresponding to NIM1 protein) and CFC1, that are upregulated in the developing testis, and BMP3 and Z-linked ADAMTSL1, that are preferentially expressed in the developing ovary. Interestingly, the expression patterns of several members of the transforming growth factor β family were sexually dimorphic, with inhibin subunits upregulated in the testis, and bone morphogenetic protein subfamily members including BMP2, BMP3, BMP4 and BMP7, upregulated in the ovary. This study also highlighted several genes displaying asymmetric expression profiles such as GREM1 and BMP3 that are potentially involved in different aspects of gonad left-right asymmetry. Conclusion/Significance : This study supports the overall conservation of vertebrate sex differentiation pathways but also reveals some particular feature of gene expression patterns during gonad development in the chicken. In particular, our study revealed new candidate genes which may be potential actors of chicken gonad differentiation and provides evidence of the preferential expression of BMPs in the developing ovary and Inhibin/Activin subunits in the developing testis

Chimie organique: tout le cours en fiches : licence, PACES, CAPES [2e édition]

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