60 research outputs found
Chromosomal control of pig populations in France: 2002-2006 survey
The chromosomal control of pig populations has been widely developed in France over the last ten years. By December 31st, 2006, 13 765 individuals had been karyotyped in our laboratory, 62% of these since 2002. Ninety percent were young purebred boars controlled before service in artificial insemination centres, and 3% were hypoprolific boars. So far, 102 constitutional structural chromosomal rearrangements (67 since 2002) have been described. Fifty-six were reciprocal translocations and 8 peri- or paracentric inversions. For the first time since the beginning of the programme and after more than 11 000 pigs had been karyotyped, one Robertsonian translocation was identified in 2005 and two others in 2006. The estimated prevalence of balanced structural chromosomal rearrangements in a sample of more than 7700 young boars controlled before service was 0.47%. Twenty-one of the 67 rearrangements described since 2002 were identified in hypoprolific boars. All were reciprocal translocations. Twelve mosaics (XX/XY in 11 individuals, XY/XXY in one individual) were also diagnosed. Two corresponded to hypoprolific boars, and three to intersexed animals. The results presented in this communication would justify an intensification of the chromosomal control of French and, on a broader scale, European and North-American pig populations
Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.
RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 â„60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Ătude chromosomique et molĂ©culaire de la sous-famille des Cervinae (application des rĂ©sultats Ă la gestion des troupeaux en captivitĂ© d'espĂšces menacĂ©es)
La sous famille des Cervinae comporte 17 espĂšces et parmi ces espĂšces, plus de la moitiĂ© sont considĂ©rĂ©es comme menacĂ©es ou vulnĂ©rables suivant les critĂšres de l'UICN. La systĂ©matique de cette sous-famille reste Ă discuter, notamment pour mieux dĂ©finir les unitĂ©s de conservation. Ce travail a pour objectifs : l'Ă©tude en cytogĂ©nĂ©tique classique et molĂ©culaire des espĂšces de la sous famille des Cervinae, l'Ă©tude des relations phylogĂ©nĂ©tiques Ă l'aide des caractĂšres chromosomiques et leur confrontation avec les donnĂ©es de gĂ©nĂ©tique molĂ©culaire, et l'Ă©tude gĂ©nĂ©tique d'une population captive d'une espĂšce menacĂ©e Cervus Duvauceli dans la perspective d'un programme de rĂ©introduction. Les travaux de cytogĂ©nĂ©tique classique et molĂ©culaire ont permis de dĂ©terminer les homoĂ©ologies entre le caryotype de la vache et celui d'une sous-espĂšce de cerf sika (C. nippon pseudaxis). La diffĂ©rence entre les caryotypes des espĂšces de Cervinae consiste en une rĂ©duction du nombre de chromosomes par translocations robertsoniennes. La plupart des chromosomes impliquĂ©s ont pu ĂȘtre identifiĂ©s par rapport aux chromosomes bovins. Les caractĂšres chromosomiques et molĂ©culaires ont permis de confirmer que la sous famille des Cervinae est monophylĂ©tique. D'aprĂšs les donnĂ©es molĂ©culaires, le genre Cervus n'est pas monophylĂ©tique car Cervus duvauceli forme avec le genre Axis et Dama un groupe monophylĂ©tique sĂ©parĂ© des autres espĂšces de Cervinae. L'Ă©tude de la population de cerfs de Duvaucel Ă l'aide de marqueurs microsatellites n'a pas permis de dĂ©terminer les liens exacts de parentĂ© entre les individus. Le nombre d'individus fondateurs de cette population a Ă©tĂ© estimĂ©. Cette population ne peut pour le moment pas ĂȘtre utilisĂ©e pour des actions de rĂ©introduction car ni la sous-espĂšce ni l'absence d'hybrides n'ont pu ĂȘtre dĂ©terminĂ©es faute d'Ă©chantillons de rĂ©fĂ©rence.TOURS-BU Sciences Pharmacie (372612104) / SudocPARIS-Museum-Bib zoologie mam. (751052312) / SudocSudocFranceF
Exploring H3K27me3 dynamic at pericentromeric heterochromatin in mouse early embryo
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Histone remodeling reflects conserved mechanisms of bovine and human preimplantation development.
How histone modifications regulate changes in gene expression during preimplantation development in any species remains poorly understood. Using CUT&Tag to overcome limiting amounts of biological material, we profiled two activating (H3K4me3 and H3K27ac) and two repressive (H3K9me3 and H3K27me3) marks in bovine oocytes, 2-, 4-, and 8-cell embryos, morula, blastocysts, inner cell mass, and trophectoderm. In oocytes, broad bivalent domains mark developmental genes, and prior to embryonic genome activation (EGA), H3K9me3 and H3K27me3 co-occupy gene bodies, suggesting a global mechanism for transcription repression. During EGA, chromatin accessibility is established before canonical H3K4me3 and H3K27ac signatures. Embryonic transcription is required for this remodeling, indicating that maternally provided products alone are insufficient for reprogramming. Last, H3K27me3 plays a major role in restriction of cellular potency, as blastocyst lineages are defined by differential polycomb repression and transcription factor activity. Notably, inferred regulators of EGA and blastocyst formation strongly resemble those described in humans, as opposed to mice. These similarities suggest that cattle are a better model than rodents to investigate the molecular basis of human preimplantation development
Histone remodeling reflects conserved mechanisms of bovine and human preimplantation development
International audienceHow histone modifications regulate changes in gene expression during preimplantation development in any species remains poorly understood. Using CUT&Tag to overcome limiting amounts of biological material, we profiled two activating (H3K4me3 and H3K27ac) and two repressive (H3K9me3 and H3K27me3) marks in bovine oocytes, 2-, 4-, and 8-cell embryos, morula, blastocysts, inner cell mass, and trophectoderm. In oocytes, broad bivalent domains mark developmental genes, and prior to embryonic genome activation (EGA), H3K9me3 and H3K27me3 co-occupy gene bodies, suggesting a global mechanism for transcription repression. During EGA, chromatin accessibility is established before canonical H3K4me3 and H3K27ac signatures. Embryonic transcription is required for this remodeling, indicating that maternally provided products alone are insufficient for reprogramming. Last, H3K27me3 plays a major role in restriction of cellular potency, as blastocyst lineages are defined by differential polycomb repression and transcription factor activity. Notably, inferred regulators of EGA and blastocyst formation strongly resemble those described in humans, as opposed to mice. These similarities suggest that cattle are a better model than rodents to investigate the molecular basis of human preimplantation development
Organisation du génome embryonnaire aprÚs la fécondation chez les mammifÚres
Chez les mammifĂšres, le gĂ©nome de lâembryon nouvellement fĂ©condĂ© est dâabord transcriptionnellement inactif. Le dĂ©veloppement embryonnaire dĂ©pend alors strictement de lâhĂ©ritage maternel en ARN et en protĂ©ines prĂ©sents dans lâovocyte et accumulĂ©s avant lâovulation. La mise en route de lâexpression des gĂšnes embryonnaires se fait ultĂ©rieurement lors de la phase appelĂ©e « activation du gĂ©nome embryonnaire (EGA) », Ă un moment de la pĂ©riode prĂ©implantatoire variable selon les espĂšces. Cette phase dâactivation est dĂ©pendante de la prĂ©sence des composants de la machinerie transcriptionnelle de base mais aussi de lâĂ©volution de lâorganisation des gĂ©nomes parentaux aprĂšs la fĂ©condation. En effet, au cours des premiers cycles embryonnaires, les noyaux subissent une rĂ©organisation intense qui constituerait un Ă©lĂ©ment clĂ© dans la rĂ©gulation du dĂ©veloppement embryonnaire
Identification by R-banding and FISH of chromosome arms involved in Robertsonian translocations in several deer species
We constructed and analyzed the RBG-banded karyotype of five deer species: Chital (Axis axis), White-lipped deer (Cervus albirostris), Rusa deer (Cervus timorensis russa), Sambar deer (Cervus unicolor) and Eld's deer (Cervus eldi siamensis). Among these five species, only Eld's deer had been previously karyotyped using R-banding. In order to identify all the chromosome correspondences with cattle and precisely which chromosome arms are involved in Robertsonian translocations, we compared the karyotypes of these five species with those of the closely related and well-characterized species, cattle (Bos taurus) and Vietnamese Sika deer (Cervus nippon pseudaxis). Among these six deer species (the five above plus the Vietnamese Sika deer), we found thirteen different Robertsonian translocations involving nineteen different chromosome arms. Thirteen chromosome arms were identified by comparison of R-banding patterns only and the remaining six were either confirmed or identified by FISH-mapping of bovine or caprine probes previously localized in cattle. Finally, we observed that five of the thirteen Robertsonian translocations are shared by at least two species and that some chromosome arms are more frequently involved in Robertsonian translocations than others. (Résumé d'auteur
Antagonist Xist and Tsix co-transcription during mouse oogenesis and maternal Xist expression during pre-implantation development calls into question the nature of the maternal imprint on the X chromosome
International audienceDuring the first divisions of the female mouse embryo, the paternal X-chromosome is coated by Xist non-coding RNA and gradually silenced. This imprinted X-inactivation principally results from the apposition, during oocyte growth, of an imprint on the X-inactivation master control region: the X-inactivation center (Xic). This maternal imprint of yet unknown nature is thought to prevent Xist upregulation from the maternal X (XM) during early female development. In order to provide further insight into the XM imprinting mechanism, we applied single-cell approaches to oocytes and pre-implantation embryos at different stages of development to analyze the expression of candidate genes within the Xic. We show that, unlike the situation pertaining in most other cellular contexts, in early-growing oocytes, Xist and Tsix sense and antisense transcription occur simultaneously from the same chromosome. Additionally, during early development, Xist appears to be transiently transcribed from the XM in some blastomeres of late 2-cell embryos concomitant with the general activation of the genome indicating that XM imprinting does not completely suppress maternal Xist transcription during embryo cleavage stages. These unexpected transcriptional regulations of the Xist locus call for a re-evaluation of the early functioning of the maternal imprint on the X-chromosome and suggest that Xist/Tsix antagonist transcriptional activities may participate in imprinting the maternal locus as described at other loci subject to parental imprinting
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