45 research outputs found
A031 Développement d’un peptido-mimétique de la glycorpotein VI plaquettaire comme outil d’imagerie de la fibrose
ObjectifLa glycoprotéine VI est le récepteur d’activation des plaquettes par les collagènes de type I et de type III. Nous avons émis l’hypothèse que nous pourrions développer une sonde spécifique du collagène basée sur la spécificité de GPVI et que cette sonde permettrait de visualiser la fibrose in vivo par une méthode non invasive.MéthodesUn anticorps bloquant la liaison de GPVI au collagène a été utilisé pour cribler une banque peptidique permettant d’identifier un motif peptidique cyclique. La capacité du peptide à mimer la GPVI a été analysée par des études de liaison et de compétition en phase solide. La liaison au collagène tissulaire a été analysée par histochimie. L’imagerie in vivo a été réalisée par injection du peptide-marqué au Tc-99m dans un modèle de fibrose cicatricielle sur infarctus du myocarde chez le rat, scintigraphie et autoradiographieRésultatsLe peptide, nommé collagelin, se lie de manière spécifique à l’anticorps anti GPVI 9O12.2 et aux collagènes I et III in vitro et la liaison est inhibée par GPVI indiquant que le peptide mime GPVI. Cependant le collagelin n’inhibe pas l’agrégation des plaquettes induite par le collagène. Les études d’histochimie montrent que le collagelin se lie au collagène tissulaire sur coupe d’aorte et de queue de rat indiquant que le collagelin se comporte comme un traceur du collagène. Dans le modèle d’infarctus cicatriciel, une accumulation du collagelin radiomarqué est observée dans la zone cardiaque par scintigraphie planaire et tomographie chez les animaux avec MI mais pas chez les animaux contrôles ni avec un peptide contrôle. L’accumulation du traceur dans les zones de fibrose a été mise en évidence ex vivo par superposition des images d’autoradiographies et d’histologie sur coupes congelées.ConclusionNous avons produit un peptide qui mime en partie le site de liaison de GPVI au collagène. Ce peptide se comporte comme un traceur spécifique du collagène in vitro et in vivo. Nous proposons que ce traceur pourrait être utile pour le diagnostic et le suivi évolutif de la fibrose dans un grand nombre de pathologies
Transcriptomic profiles of muscle, heart, and spleen in reaction to circadian heat stress in Ethiopian highland and lowland male chicken
Temperature stress impacts both welfare and productivity of livestock. Global warming is expected to increase the impact, especially in tropical areas. We investigated the biological mechanisms regulated by temperature stress due to the circadian temperature cycle in temperature adapted and non-adapted chicken under tropical conditions. We studied transcriptome profiles of heart, breast muscle, and spleen tissues of Ethiopian lowland chicken adapted to high circadian temperatures and non-adapted Ethiopian highland chicken under lowland conditions at three points during the day: morning, noon, and evening. Functional annotations and network analyses of genes differentially expressed among the time points of the day indicate major differences in the reactions of the tissues to increasing and decreasing temperatures, and also the two chickens lines differ. However, epigenetic changes of chromatin methylation and histone (de)acetylation seemed to be central regulatory mechanisms in all tissues in both chicken lines. Finally, all tissues showed differentially expressed genes between morning and evening times indicating biological mechanisms that need to change during the night to reach morning levels again the next day.</p
Immune-Mediated Change in the Expression of a Sexual Trait Predicts Offspring Survival in the Wild
BACKGROUND: The "good genes" theory of sexual selection postulates that females choose mates that will improve their offspring's fitness through the inheritance of paternal genes. In spite of the attention that this hypothesis has given rise to, the empirical evidence remains sparse, mostly because of the difficulties of controlling for the many environmental factors that may covary with both the paternal phenotype and offspring fitness. Here, we tested the hypothesis that offspring sired by males of a preferred phenotype should have better survival in an endangered bird, the houbara bustard (Chlamydotis undulata undulata). METHODOLOGY/PRINCIPAL FINDINGS: We tested if natural and experimentally-induced variation in courtship display (following an inflammatory challenge) predicts the survival of offspring. Chicks were produced by artificial insemination of females, ensuring that any effect on survival could only arise from the transfer of paternal genes. One hundred and twenty offspring were equipped with radio transmitters, and their survival monitored in the wild for a year. This allowed assessment of the potential benefits of paternal genes in a natural setting, where birds experience the whole range of environmental hazards. Although natural variation in sire courtship display did not predict offspring survival, sires that withstood the inflammatory insult and maintained their courtship activity sired offspring with the best survival upon release. CONCLUSIONS: This finding is relevant both to enlighten the debate on "good genes" sexual selection and the management of supportive breeding programs
Association between heat stress and oxidative stress in poultry; mitochondrial dysfunction and dietary interventions with phytochemicals
Recent Asian origin of chytrid fungi causing global amphibian declines
Globalized infectious diseases are causing species declines worldwide, but their source often remains elusive. We used whole-genome sequencing to solve the spatiotemporal origins of the most devastating panzootic to date, caused by the fungus Batrachochytrium dendrobatidis, a proximate driver of global amphibian declines. We traced the source of B. dendrobatidis to the Korean peninsula, where one lineage, BdASIA-1, exhibits the genetic hallmarks of an ancestral population that seeded the panzootic. We date the emergence of this pathogen to the early 20th century, coinciding with the global expansion of commercial trade in amphibians, and we show that intercontinental transmission is ongoing. Our findings point to East Asia as a geographic hotspot for B. dendrobatidis biodiversity and the original source of these lineages that now parasitize amphibians worldwide
Cross-tolerance: embryonic heat conditioning induces inflammatory resilience by affecting different layers of epigenetic mechanisms regulating IL6
Effect of low incubation temperature and low ambient temperature until 21 days of age on performance and body temperature in fast-growing chickens
Carboxypeptidase U (CPU, carboxypeptidase B2, activated thrombin-activatable fibrinolysis inhibitor) inhibition stimulates the fibrinolytic rate in different invitro models
A031 Développement d’un peptido-mimétique de la glycorpotein VI plaquettaire comme outil d’imagerie de la fibrose
Microbiome function predicts amphibian chytridiomycosis disease dynamics
Background The fungal pathogen Batrachochytrium dendrobatidis (Bd) threatens amphibian biodiversity and ecosystem stability worldwide. Amphibian skin microbial community structure has been linked to clinical outcome of Bd infections, yet its overall functional importance is poorly understood. Methods Microbiome taxonomic and functional profiles were assessed using high-throughput bacterial 16S rRNA and fungal ITS2 gene sequencing, bacterial shotgun metagenomics and skin mucosal metabolomics. We sampled 56 wild midwife toads (Alytes obstetricans) from montane populations exhibiting Bd epizootic or enzootic disease dynamics. In addition, to assess whether disease-specific microbiome profiles were linked to microbe-mediated protection or Bd-induced perturbation, we performed a laboratory Bd challenge experiment whereby 40 young adult A. obstetricans were exposed to Bd or a control sham infection. We measured temporal changes in the microbiome as well as functional profiles of Bd exposed and control animals at peak infection. Results Microbiome community structure and function differed in wild populations based on infection history and in experimental control versus Bd-exposed animals. Bd exposure in the laboratory resulted in dynamic changes in microbiome community structure and functional differences, with infection clearance in all but one infected animal. Sphingobacterium, Stenotrophomonas and an unclassified Commamonadaceae were associated with wild epizootic dynamics and also had reduced abundance in laboratory Bd-exposed animals that cleared infection, indicating a negative association with Bd resistance. This was further supported by microbe-metabolite integration which identified functionally relevant taxa driving disease outcome, of which Sphingobacterium and Bd were most influential in wild epizootic dynamics. The strong correlation between microbial taxonomic community composition and skin metabolome in the laboratory and field are inconsistent with microbial functional redundancy, indicating that wholesale differences in microbial taxonomy drive functional variation. Shotgun metagenomic analyses support these findings, with similar disease-associated patterns in beta diversity. Analysis of differentially abundant bacterial genes and pathways indicated that bacterial environmental sensing and Bd resource competition are important in driving infection outcome. Conclusions Bd infection drives altered microbiome taxonomic and functional profiles across laboratory and field environments. Our application of multi-omics analyses in experimental and field settings robustly predict Bd disease dynamics and identify novel candidate biomarkers of infection