HAL Université de Tours
Not a member yet
55851 research outputs found
Sort by
The effects of rearing kids with non-lactating goats on kids’ behavioural development
No full textInternational audienc
Shelter use in horses: Time spent indoors and factors of variation – Results from a one-year longitudinal study
No full textInternational audienceStabling is a common lifestyle for horses, yet numerous studies show that it negatively impacts their welfare, leading to behavioural and health issues. In this study, we aimed to determine how much time horses choose to spend inside their stalls when given the option to be inside (in shelters/stalls) or outside at pasture. Using permanently installed night-vision cameras inside the stalls, we recorded 53 horses across 20 sites in temperate climates (France, Belgium) over a full year. We analyzed their stall presence and activity (lying down, observe, stand at rest, eat, etc.) for 72 consecutive hours each month over 12 months. The results show that, on average, horses spend only 3 h per day inside, and not consecutively (entering 2.5 times per day). There is a strong seasonal effect: horses spend twice as much time in their stalls in summer than in winter. This finding is notable as it contrasts with the usual advice of stabling horses in winter and turning them out to pasture in summer. In winter, horses predominantly return to their stalls late at night (00:00-06:00) to eat and lie down, while in summer, they return in the afternoon (12:00-18:00) to rest standing. Contrary to expectations, presumably rustic breeds (ponies) spent more time inside, and age had no effect on this, indicating that stalls are essential for all types of horses. Additionally, the larger the shelter (in sq m per horse), the more it is used. Stalls fully enclosed with a single access door are also associated with higher usage in summer, winter, and autumn, compared to an open shelter. The use of blankets in winter or fly masks in summer is not associated with a reduction of the time spent in the stalls, suggesting that these accessories do not substitute for shelter. There is also significant inter-individual variability among horses: the ideal is to allow them the freedom to come and go as they please in order to best respect their agency and individual needs
Two-State Stochastic Model of In Vivo Observations of Transcriptional Bursts
No full textInternational audienceIn vivo measurements of gene expression in single cells show behavior that has been interpreted as stochastic bursts of transcription. In one case, these data have been interpreted as random ON–OFF transitions of the gene, but there is no experimental measurements or theoretical treatment of the number of transcripts produced at each burst event. In another case, such data have been interpreted to indicate multiple underlying transcriptional states. Here, we place both of these experiments in a common theoretical framework. In it, we couple two stochastic processes, one for synthesis of transcripts and one for their removal. Analysis of the resulting model is greatly aided by the existence of exact solutions of the master equation. We find the bursting limit of the exact solutions for our two-state gene expression model and show the occurrence of bursts of multiple sizes and durations by exact stochastic simulations. We also demonstrate that data from Drosophila melanogaster interpreted in terms of multiple underlying transcription states is fully compatible with underlying two-state ON or OFF transcriptional behavior. We discuss what experimental data is required to unambiguously determine the number of underlying promoter states
Specialized transduction of a prophage carrying antimicrobial resistance genes by virulent Escherichia phage vB_EcoM_Goslar among Enterobacterales
No full textInternational audienceBackground and objectives: In the order Enterobacterales, acquired antimicrobial resistance genesspread mainly on conjugative elements such as plasmids and integrative elements. Phage genomesrarely encode antimicrobial resistance genes. Here, a novel temperate Enterobacteria phage carryingseveral antimicrobial resistance genes, notably blaCTX-M-55, was identified in Escherichia coliisolates from poultry. Genetic and phenotypic characterization of this novel phage was carried out.Methods: Horizontal transfers were initially performed from E. coli field isolates into sodium-azidresistant recipient E. coli strain J5-3. Then, phage particles were purified by PEG/NaCl precipitation.Transduction assays were realized into different E. coli lab strains and Enterobacterales species todetermine host range. Field strains, lysogenic recipients and phage lysates were analyzedphenotypically and genetically by antimicrobial susceptibility testing, transmission electron microscopy,plaque formation assays, and whole-genome sequencing.Results: Two nearly-identical representatives of a novel Enterobacteria phage, named respectivelyphEC_B25FEP & phEC_M24FEP, were identified by horizontal transfer assays of the ESBL geneblaCTX-M-55 from 2 distinct E. coli donor strains of broilers. These phages were first identified as 72-kb prophages specifically integrated at the 3"-end of tRNA-Phe into the chromosome of lysogenicrecipients. They harbored resistance to chloramphenicol/florfenicol (floR), tetracyclines (tetA),streptomycin (aph(3"")-Ib/aph(6)-Id, sulphonamides (sul2) and expanded-spectrum cephalosporins(ISEcp1-blaCTX-M-55). Beside phage-specific genes, phages phEC_B25FEP & phEC_M24FEP alsocarried the raffinose metabolism operon rafRABDY, a N6A type I restriction/modification system, andseveral pathogenicity-related genes. Phage lysate preparation and transduction assays revealed a ca.105/ml transduction efficiency. Plaque assays confirmed the lysis capacity of E. coli host, howeverindividual lysis plaques were not visible. Based on blast search in NCBI database and in vitro hostrange determination, phEC_B25FEP & phEC_M24FEP appeared restricted to E. coli and Salmonella.This Enterobacteria phage represents a novel phage genus not yet described among bacteriophagesin public databases (Refseq, Genbank, VIRIDIC). Phage particles have a typical icosahedral head anda short contractile tail and carry the double-stranded DNA phage genome. Induction assays usingvarious antibiotics as well as mitomycin C did not show any increase in transduction efficiency.Conclusions: A novel family of active temperate phages carrying antimicrobial resistance genes,especially the ESBL gene blaCTX-M-55 was characterized in avian E. coli isolates. The co-localizationof antimicrobial resistance genes, metabolism function, pathogenicity-related factors may increase therisk for co-selection, persistence and dissemination in food-producing animals
Relation entre la dissociation état/trait et les fonctions cognitives: une étude combinant une approche transversale et une démonstration expérimentale auprès de la population générale et de patients atteints de TSPT
No full textInternational audienceIntroduction: It is often proposed that dissociation would be associated to cognitive disruption. However, the studies exploring the relationship between dissociation and cognition are incongruent. Some authors suggest that this is due to 1) the tools used to measure trait-dissociation, 2) the absence of measure of state-dissociation, 3) the absence of emotional material in cognitive evaluation and 4) the absence of experimental studies. The study will therefore (i) explore the association between state-dissociation and multiple cognitive functions in neutral condition (ii) evaluate the impact of emotional activation on cognitive performance and its association dissociation, (iii) induce dissociation using experimental induction and (iv) change the tools evaluating trait-dissociation.Method: We recruited 100 participants form the general population (57 women) and 56 patients suffering from Posttraumatic Stress Disorder (PTSD) (52 women) who undertook several evaluations of dissociation, PTSD, emotion regulation and cognitive complaints. They performed a neuropsychological battery evaluating executive function, denomination, reaction time and memory. Half of the participants undertook a detection task after a dissociative induction while the other half performed the same task without induction.Results: We found a significant association between trait and state dissociation with multiple tasks: Stroop tasks, go/no go task, detection task and denomination tasks. We found a significant effect of dissociative induction on both reaction time and dissociative state.Conclusion: This argues in favor of Vancappel and El Hage’s model suggesting that the relationship between cognitive function and dissociation is bidirectional. First, poor cognitive abilities tend to be predictive of dissociative symptoms. Second, dissociative state tend to alter attentional abilities. Further explorations are now required on larger clinical samples.Introduction : Il est souvent proposé que la dissociation soit associée à une perturbation cognitive. Cependant, les études explorant la relation entre la dissociation et la cognition sont incongruentes. Certains auteurs suggèrent que cela est dû à: 1) les outils utilisés pour mesurer la dissociation-trait, 2) l’absence de mesure de la dissociation-état, 3) l’absence de matériel émotionnel dans l’évaluation cognitive et 4) l’absence d’études expérimentales. Cette étude vise donc à: (i) explorer l’association entre la dissociation-état et plusieurs fonctions cognitives en condition neutre, (ii) évaluer l’impact de l’activation émotionnelle sur la performance cognitive et son association avec la dissociation, (iii) induire expérimentalement un état dissociatif et (iv) modifier les outils d’évaluation de la dissociation-trait.Méthode : Nous avons recruté 100 participants issus de la population générale (57 femmes) et 56 patients souffrant de trouble de stress post-traumatique (TSPT) (52 femmes). Ils ont été soumis à plusieurs évaluations de la dissociation, du TSPT, de la régulation émotionnelle et des plaintes cognitives. Ils ont ensuite réalisé une batterie neuropsychologique évaluant les fonctions exécutives, la dénomination, le temps de réaction et la mémoire. La moitié des participants a effectué une tâche de détection après une induction dissociative, tandis que l’autre moitié a réalisé la même tâche sans induction.Résultats : Nous avons trouvé une association significative entre la dissociation-trait et la dissociation-état avec plusieurs tâches: les tâches de Stroop, la tâche go/no-go, la tâche de détection et les tâches de dénomination. Nous avons également observé un effet significatif de l’induction dissociative sur le temps de réaction ainsi que sur l’état dissociatif.Conclusion : Ces résultats soutiennent le modèle de Vancappel et El Hage, qui suggère que la relation entre les fonctions cognitives et la dissociation est bidirectionnelle. D’une part, de faibles capacités cognitives tendent à prédire l’apparition de symptômes dissociatifs. D’autre part, l’état dissociatif altère les capacités attentionnelles. Des explorations complémentaires sur des échantillons cliniques plus larges sont désormais nécessaires
HARMONI: Evaluating advanced microbiota characterization methods for host and environmental samples using DNA metabarcoding and metagenomic sequencing
No full textInternational audienceBackground: The study of microbiota and their actions on the environment and their living hosts is a major field of biology, today and for decades to come. Understanding and controlling the microbiota associated with plants, animals and food is a lever for achieving the objectives of the transition to sustainable agricultural production systems. Research faces many technical challenges that must be overcome before reaching meaningful and reproducible biological conclusions. In this context, biological resource centres (BRCs) must be prepared to the processing and characterization of microbiota-oriented samples, in the continuity of their missions of collection, preservation and distribution of perfectly characterized biological resources. Results: In the HARMONI project, five BRCs worked collaboratively to implement and assess methods for microbiota analyses. Samples were collected from a diversity of sources: chicken caeca, human feces, kefir and soil. The data were generated using 16S metabarcoding, short read metagenomic sequencing, and long read metagenomic sequencing. We tested different tools for microbial exploration, using reference free softwares for alpha and beta diversity assessment (SIMKA [1], ESKRIM [2]), and referenceguided microbial annotation using MetaPhlAn4 [3], sylph [4] and Meteor2 [5]. Conclusions: Overall, metabarcoding and metagenomic based microbial composition are in agreement with the major impacts observed between the different sample treatment technics. However, the microbial richness and species composition exploration significantly depend on the sequencing method and software used and their associated database. Finally, while long read metagenomic sequencing provide consistent results with metagenomic short read for microbial annotation, it highly depend on the quality of the sample treated. The HARMONI project was funded by the GIS-IBISA convention N° 2021-203
Mixed genetic background better recapitulates developmental and psychiatric phenotypes and heterogeneity than inbred C57BL/6J mice
No full textPreclinical models of neurodevelopmental and psychiatric conditions often rely on inbred mouse strains like C57BL/6J (B6), which exhibit limited genetic and behavioral variability. This limitation hampers the modeling of phenotypic heterogeneity, characteristic of these conditions. Recent efforts have explored the use of multiple genetically diverse hybrid strains to address this. In this study, we examined whether one single mixed genetic mouse background, C57BL/6J;129S2/SvPas (B6;129), could simultaneously recapitulate behavioral variability and display improved phenotypes relevant to neurodevelopmental and psychiatric conditions. Compared to the inbred B6 strain, mixed B6;129 mice displayed enhanced sociability and self-grooming, two key discriminating parameters between the two mouse backgrounds and core features of such conditions, alongside a broader spectrum of individual behavioral variability. Although overall behavioral variability was comparable across backgrounds, B6;129 mice were less susceptible to the effects of chronic social isolation than their B6 counterparts.Together, these findings support that the B6;129 mixed background offers a more representative model of individual variability and behavioral traits associated with neurodevelopmental and psychiatric conditions, thereby enhancing its translational relevance in preclinical studies.</p
Novel lanthanide(III)/gallium(III) metallacrowns with appended visible-absorbing organic sensitizers for molecular near-infrared imaging of living cells
No full textInternational audienceOptical imaging of biological samples in the near-infrared (NIR) domain is of major interest for non-invasive experiments due to reduced light scattering, absorption and autofluorescence. Taking advantage of the maleimide moieties in the [Ln2Ga8(shi)8(mip)4] metallacrowns (MCs; shi = salicylhydroximate; mip = 5-maleimido-isophthalate; Ln = NdIII, GdIII, ErIII, YbIII and YIII), we appended visible-absorbing thiol-coumarin (C) sensitizers through a thiol-Michael addition click reaction, affording the functionalized [Ln2Ga8(shi)8(C-mip)4] MCs. By using this approach, the sensitization of NIR-emitting NdIII, ErIII and YbIII was achieved upon excitation in the visible range (λ = 420 nm) through the appended coumarins. NIR epifluorescence microscopy of living HeLa cells incubated with the NdIII derivative confirmed unambiguous detection of the signal arising from the F → I electronic transition in the range of 1050–1080 nm in the cells. These results demonstrate that the [Ln2Ga8(shi)8(mip)4] MC can be used as a versatile molecule for tuning the chemical and photophysical properties of the [Ln2Ga8] MC family
Avis de l’Anses relatif au projet de décret relatif à la modification de la liste des techniques d’obtention d’organismes génétiquement modifiés ayant fait l’objet d’une utilisation traditionnelle et dont la sécurité pour la santé publique ou l’environnement est avérée depuis longtemps
No full textCitation suggérée : Anses. (2025). Avis de l’Agence nationale de sécurité sanitaire de l’alimentation, de l’environnement et du travail relatif au projet de décret relatif à la modification de la liste des techniques d’obtention d’organismes génétiquement modifiés ayant fait l’objet d’une utilisation traditionnelle et dont la sécurité pour la santé publique ou l’environnement est avérée depuis longtemps. Saisine 2024-SA-0163. Maisons-Alfort : Anses, 15 p.L’Anses a été saisie le 21 novembre 2024 par la Direction générale de l’alimentation (DGAl) et la Direction générale de la prévention des risques (DGPR) pour : « rendre un avis sur le projet de décret relatif à la modification de la liste des techniques d’obtention d’organismes génétiquement modifiés ayant fait l’objet d’une utilisation traditionnelle et dont la sécurité pour la santé publique ou l’environnement est avérée depuis longtemps, en application de l’articleL. 531-2 du code de l’environnement. »CONTEXTE ET OBJET DE LA SAISINEConformément à l’article L. 531-2 du Code de l’environnement, la liste des techniques, citées dans l’article D. 531-2, permettant d’obtenir des organismes génétiquement modifiés (OGM), ayant « fait l’objet d’une utilisation traditionnelle sans inconvénient avéré pour la santé publique ou l’environnement », et dont les produits ne sont donc pas soumis aux dispositions prévues par les articles L. 125-3, L. 515-13 et L. 531-1 à L. 537-1 du Code de l’environnement, est fixée par décret après avis de l’Anses.Suite à un recours engagé en 2015 par la Confédération paysanne et d’autres organisations portant sur les variétés rendues tolérantes aux herbicides, notamment celles obtenues au moyen de techniques de mutagenèse, le Conseil d’État (CE) a interrogé à deux reprises la Cour de justice de l’Union européenne (CJUE) sur les techniques permettant d’obtenir des OGM entrant dans le champ d’application de la directive n° 2001/18/CE1. Les conclusions de la CJUE sont exposées dans deux arrêts, rendus les 25 juillet 20182 et 7 février 20233.Afin de mettre en œuvre les décisions du CE du 7 février 20204 et du 23 octobre 20245, prenant en compte ces deux arrêts, un projet de décret a été élaboré par les autorités françaises.Dans ce contexte, la DGAl et la DGPR ont donc saisi l’Anses pour avis sur le projet de décret relatif à la modification de l’article D.531-2 du Code de l’environnement.Le CE précise, au considérant 5. de sa décision du 23 octobre 2024, qu’ « il appartient au Premier ministre d'adopter un projet de décret modifiant l'article D. 531-2 du code de l'environnement, qui fixe la liste des techniques permettant l'obtention d'organismes génétiquement modifiés qui, en application de l'article L. 531-2 du même code, ne sont pas soumis aux dispositions du titre III du livre V de ce code, afin d'ajouter, au premier alinéa, après les mots « comme donnant lieu à une modification génétique », les mots « ou qui ont fait l'objet d'une utilisation traditionnelle et dont la sécurité pour la santé publique ou l'environnement est avérée depuis longtemps », et au a) du 2°, après le mot « mutagenèse », le mot « aléatoire » ».Le CE précise que le décret devra être adopté dans un délai de quatre mois à compter de sa décision, après avis de l’Anses