HAL ENVT (Ecole Nationale Vétérinaire de Toulouse)
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Development of an LC-MS/MS method for the simultaneous quantification of 11 perfluoroalkyl compounds in mouse plasma for toxicokinetic applications
No full textInternational audienceFollowing regulatory pressure, the manufacture of long-chain per- and polyfluoroalkyl substances (PFAS) has been phased out, and alternatives such as short-chain homologs and ether-PFAS have replaced the bioaccumulative long-chain PFAS. However, data are lacking regarding the toxicokinetic (TK) properties of certain PFAS, particularly emergent substitutes for long-chain compounds. Additionally, the existing analytical methods used for TK studies measure a single compound or only a few simultaneously. For this reason, an LC-MS/MS method was developed for the simultaneous quantification in mouse plasma of 11 PFAS representative of some of the most important categories of these compounds, for application in TK studies. The method was successfully validated in the range of 0.5-1000 ng/mL, in accordance with the European Medicines Agency guidelines, and applied to a 24-h pilot TK study conducted in mice. All compounds were monitored over 24 hours in the pilot study. The present method is therefore suitable for the simultaneous quantification of PFAS in plasma samples and can be applied for future TK studies
Inférence de la démographie et de la sélection à partir de séries temporelles de données génomqiues
No full textNational audienceCollecting DNA samples for the same population at several generations arises in various contexts, including experimental evolution, the monitoring of wild or domestic populations or paleo-genomic ancient DNA studies. In contrast with DNA sampling designs based on a single time point (the present), such data provide direct access to the genetic diversity changes occurring within a specific time period, informing us about both the demographic and adaptive processes acting on the population during that period. This talk will describe past and ongoing work concerning the development of a statistical method estimating population size or / and selection intensity at each locus from genomic time series data
‘Implementation of bio…what?’ Farm workers’ subjectivities in Spanish dairy cattle farms through an ethnographic approach
No full textInternational audienceThis study explores the implementation of biosecurity measures by farm workers through daily work routines on dairy cattle farms in Spain. The implementation of biosecurity measures on dairy cattle farms is mainly decided by farmers and veterinarians, but it is carried out by both farmers and farm workers. However, farm workers may be affected by socio-employment factors such as the precariousness of their work such that implementation of biosecurity measures may be context dependent and may differ from official recommendations. An ethnographic approach was used through observations and conversations on four farms in two regions of Spain, two in Galicia (north-west) and two in Catalonia (north-east) to explore these factors. The profiles of participants were farmerfamily workers, internal worker-employees and external worker-employees. Results showed that there were social differences, particularly communicative and hierarchical differences, between workers and farmers that influenced the implementation of biosecurity measures. Workers implemented biosecurity practices incompletely, differently or incorrectly from their supervisors' instructions. Workers also relied on what the authors called an anthropomorphic approach to implementing biosecurity measures, which deviated from farm guidelines. In order to improve the implementation of biosecurity measures on dairy cattle farms, it is necessary to consider workers as key stakeholders in biosecurity. Such consideration could also help to professionalise workers, reduce their turnover and increase their permanence on these farms
Propriétés conjugatives de Mycoplasma agalactiae et Mycoplasma bovis ex vivo
No full textInternational audienceLa découverte de transferts horizontaux de gènes (THG) chez les mycoplasmes a mis en lumière des mécanismes conjugatifs originaux conférés par des éléments génétiques mobiles intégratifs et conjugatifs (ICE). Les propriétés conjugatives conférées par les ICEs ont été principalement étudiées in vitro et les informations sur l’importance du THG in vivo restent anecdotiques. Dans cette étude, nous avons utilisé Mycoplasma agalactiae, un pathogène des petits ruminants, comme modèle afin de comparer les propriétés conjugatives de ce mycoplasme dans des environnements de complexité croissante. Des expériences de conjugaison ont été réalisées dans des conditions axéniques ainsi que dans des conditions de cultures cellulaires et organotypiques (conditions ex vivo). Les résultats ont révélé des fréquences de conjugaison jusqu’à 200 fois plus élevées en conditions ex vivo par rapport aux conditions axéniques. Des résultats similaires ont été observés avec Mycoplasma bovis, un pathogène des bovins, pour lequel aucun évènement de conjugaison n’a été observé en conditions axéniques. Ces résultats fournissent des modèles intéressants pour l’étude de ces mécanismes et permettent d’étayer la possible importance du THG dans l’évolution des mycoplasmes in vivo
Phenotype‐Specific Semi‐Mechanistic Modelling of Florfenicol Time‐Kill Curves in G. Parasuis Compared to Other Respiratory Pathogens
No full textInternational audienceThis study examines the pharmacodynamics (PD) of florfenicol (FFN) for treating porcine respiratory diseases by comparing its effects on Glaesserella parasuis , Actinobacillus pleuropneumoniae and Pasteurella multocida . In vitro time‐kill assays and semi‐mechanistic PD modeling were used to assess bacterial growth and killing rates at varying FFN concentrations. Species‐specific PD models indicated that f AUC/MIC was the best PK/PD index across all species. A. pleuropneumoniae and P. multocida had target values of 1.05 and 1.66 × MIC, respectively for bacteriostasis and 1.12 and 1.87 × MIC for 99.9% kill. Two phenotypes of G. parasuis emerged “fast‐kill” and “slow‐kill” which displayed distinct bacterial eradication rates despite similar MICs. For “slow‐kill” isolates, an average free drug concentration ( f AUC/MIC) of 1.46 and 1.63 × MIC (median, range: 1.53–1.69) was required for bacteriostasis and 99.9% kill. “Fast‐kill” isolates needed an average free drug concentration of 1.38 × MIC for bacteriostasis and 1.51 × MIC for a 99.9% reduction. Indicating that the rate of kill influences the respective average free concentration required to achieve an equivalent antibacterial effect. Simulations of clinical dosing of FFN predicted bacterial eradication for all species, highlighting the value of phenotype‐specific PD modeling in guiding treatment strategies for porcine respiratory infections
Parent-of-origin regulation by maternal auts2 shapes neurodevelopment and behavior in fish
No full textInternational audienceBackground Parental experience can influence progeny behavior through gamete-mediated non-genetic inheritance, that is, mechanisms that do not involve changes in inherited DNA sequence. However, underlying mechanisms remain poorly understood in vertebrates, especially for maternal effects. Here, we use the medaka, a model fish species, to investigate the role of auts2a , the ortholog of human AUTS2 , a gene repressed in the fish oocyte following maternal stress and associated with neurodevelopmental disorders. Results We show that auts2a expression in the oocyte influences long-term progeny behavior, including anxiety-like behavior and environment recognition capabilities. Using single-nuclei RNA-sequencing, we reveal that maternal auts2a influences gene expression in neural cell populations during neurodevelopment. We also show that maternal auts2a knock-out triggers differences in maternally inherited factors, including early embryonic transcriptional and post-transcriptional regulators. Conclusions Together, our results reveal the unsuspected role of an autism-related gene expressed in the mother’s oocyte in shaping progeny neurodevelopment and behavior. Finally, we report that auts2a/AUTS2 is part of a group of evolutionarily conserved genes associated with human neurodevelopmental disorders and expressed in oocytes across species, from fish to mammals. These findings raise important questions about their potential role in the non-genetic regulation of progeny neurodevelopment and behavior in vertebrates
Interaction génotoxique entre le déoxynivalénol et l'acrylamide
No full textInternational audienceFood safety represents a major global concern. Humans and animals are exposed to a broad spectrum of food contaminants, which implies probable cocktail effects. Around 80 % of the population is exposed to deoxynivalenol (DON), one of the most widespread mycotoxins mainly found in cereal products. DON has previously been shown to exacerbate DNA damage induced by various compounds, questioning on potential toxic interactions with genotoxic food contaminants. Among them, acrylamide, classified as probably carcinogenic to humans, is formed during cooking processes and commonly found in fried foods and cereal products. Considering that co-consumption of DON-and/or acrylamide-contaminated foods is highly probable, we evaluated their genotoxic interaction in a non-cancerous intestinal cellular model. Our data show that DON exacerbates the cytotoxic and genotoxic activities of acrylamide, assessed through the analysis of the DNA damage biomarker γH2AX and by comet assay. This was corroborated by transcriptomic analyzes pointing out enhanced DNA repair pathway under co-exposure. Of note, DON-mediated increase of acrylamide-induced DNA damage is not related to the apoptotic program. As a consequence of this genotoxic interaction, cells co-exposed to DON and acrylamide exhibit more important cell cycle defects and chromosomal instability, as evaluated by the chromosomal aberration assay. In conclusion, our work shows that DON exacerbates the genotoxicity of acrylamide, with repercussions on the maintenance of genetic stability, potentially implying an increased carcinogenic risk. These results therefore provide crucial information regarding food safety, given the high probability of cocontamination by DON and genotoxic agents such as acrylamide
Risk of incident cancer in patients with Inflammatory Bowel Disease with prior breast cancer: a multicenter cohort study
No full textInternational audienceBackground and AimsBreast cancer is the most common malignancy observed in patients with inflammatory bowel diseases (IBD). The aim of our study was to evaluate incident cancer rate (recurrence or new-onset cancer) in a cohort of IBD patients with a history of breast cancer according to the subsequent IBD treatment provided.MethodsA multicenter retrospective study included consecutive IBD patients with prior breast cancer. The inclusion date corresponded to the diagnosis of index malignancy. Follow-up lasted from cancer diagnosis until the occurrence of incident cancer.ResultsAmong 207 patients included (median disease duration: 13 years [IQR 6 - 21]), first line treatment (median interval of 28 months [IQR 7 - 64]) was a conventional immunosuppressant in 19.3 % of patients, anti-TNF in 19.8 %, vedolizumab in 7.2 % and ustekinumab in 1.9 %.After a median follow-up of 71 months [IQR, 34 - 148], 42 (20%) incident cancers were observed (34 breast cancer recurrences). Adjusted incidence rates per 1000 person-years were 10.2 (95%CI 6.0- 16.4) for the untreated arm and 28.9 (95%CI 11.6-59.6) for exposed patients (p= 0.0519). There was no significant difference between treated patients and controls regarding incident-cancer free survival rates (p=0.4796). In multivariable analysis, factors associated with incident cancer were stage T4d (p=0.036), triple negative tumor (p=0.016) and follow-up of less than 71 months (p=0.005).ConclusionWe did not find a statistically significant increase in incident breast cancer related to IBD treatment beyond the already known poor prognostic factors of breast cancer
FISH , a new tool for in situ preservation of RNA in tissues of deep‐sea mobile fauna
No full textInternational audienceAccessing the metabolic functioning of deep‐sea animals in situ remains a technological challenge as the recovery time of samples is incompatible with the short lifespan of such molecules as mRNAs. Tools able to preserve RNA in situ exist, but they are incompatible with the study of mobile fauna. Here, we describe a new sampling tool, named FISH (fixer in situ of homogenized substrates), implemented on a submersible and equipped with a number of new specific features to collect and preserve in situ tissue of mobile fauna. Connected to the suction pump of a submersible, the FISH sampler incorporates a sampling bowl to which two bottles of a preservative reagent are attached, a suction hose, and a support containing a motor connected to the sampling bowl by a magnetic coupling system. We used the deep‐sea hydrothermal shrimp Rimicaris exoculata from the Mid‐Atlantic Ridge as a model to test the suitability of our new tool. The FISH sampler was compared to two other sampling methods, which use a metatranscriptomic approach targeting microbial communities associated with cephalothorax symbionts. RNA quality, gene assignment, and taxonomic and gene function diversity showed differences between in situ and on‐board preservation of tissues. Of the alternative sampling methods tested, the suction sampler was clearly not suitable for RNA‐based studies, while pressurized recovery showed results closer to the sample quality obtained with FISH sampling. The FISH sampler has therefore demonstrated to be a cost‐effective and reliable tool to efficiently preserve RNA recovered from deep‐sea environments