Publications scientifiques de l'EnvA
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Coprology or serology: which is the most appropriate diagnostic test for defining the status of a farm regarding A. suum?
No full textInternational audienc
CRISPR-Cas9 gene-editing to assess the role of RF-amide−related peptide 3 in ovine seasonal breeding
No full textInternational audienceSeasonal breeding is an adaptive strategy that ensures the birth of the offspring during the best time of year and allows energy saving in times of food scarcity and adverse environmental conditions. At temperate and polar latitudes, photoperiod is the main synchroniser of seasonal functions, which exerts its action through melatonin. Within the pars tuberalis of the anterior pituitary, melatonin triggers a series of events that lead to enhanced local triiodothyronine (T3) production in the medio-basal hypothalamus specifically under long days and ultimately drive the appropriate GnRH output at the median eminence. How T3 governs GnRH output is mostly unknown but neuronal populations that respectively produce KISS1 and RFRP3 appear to be involved. However, while the role of KISS1 as a major GnRH secretagogue is undisputed, the function of RFRP3 in the control of (seasonal) breeding remains enigmatic, with conflicting results hinting at elusive mechanisms. Therefore, we launched an extensive series of experiments in sheep, aimed at invalidating the NPVF gene, which encodes RFRP3, using CRISPR-Cas9 technology.Here, we report on the generation of six sheep for which the NPVF gene has been successfully edited. Four of these animals bear at least one allele expected to behave as a null and constitute founders for distinct ovine lines. These founder sheep will now enter a standard breeding scheme in order to obtain male and female homozygotes for distinct mutations. These animals are expected to provide a clear delineation of the function of RFRP3 in seasonal breeding.</p
Médecine préventive chez le chien : état des lieux et étude comparée des recommandations actuelles en France et dans le monde
No full textIn recent years, the number of pets in French households has increased, and pet owners are increasingly travelling abroad with their pets. Such travel exposes both pets and humans to various infectious risks. The first part of this bibliographic thesis is devoted to the internal and external parasites that can cause clinical disease in dogs and to the antiparasitics available on the market in France in 2024. The second part similarly details the viruses to which dogs are exposed, the associated vaccines and their recommendations for use. Finally, the third part of the book summarises current regulations on the non-commercial movement of pets in Europe and worldwide. This part also draws on the previous sections to give vaccination and anti-parasite recommendations tailored to each destination country. Advice on preparing to travel with your pet is now an integral part of preventive medicine. Good communication with the owner about the risks involved, the means of prevention and the regulations will help to limit these risks. It's also important to warn owners that it can take several months for their pet to comply with the regulations, so it's important to plan ahead. Regulations on importing pets can change from one year to the next, so it's a good idea for owners to check with the governments of the destination countries as well.Ces dernières années le nombre d'animaux de compagnie au sein des foyers français a augmenté et les propriétaires se déplacent de plus en plus à l'étranger accompagnés de leur animal. Ces déplacements exposent les animaux mais aussi les humains à des risques infectieux divers. La première partie de cette thèse bibliographique se consacre aux parasites internes et externes pouvant causer des maladies cliniques chez le chien et aux antiparasitaires présents sur le marché en France en 2024. La seconde partie détaille de la même manière les virus auxquels sont exposés les chiens et les vaccins associés ainsi que leurs recommandations d'utilisation. Enfin la troisième partie de cet ouvrage a pour vocation de résumer la réglementation actuelle sur les mouvements non commerciaux d'animaux de compagnie en Europe et dans le monde. Cette partie s'appuie également sur les précédentes pour donner des recommandations vaccinales et antiparasitaires adaptées à chaque pays de destination. Les conseils pour préparer un voyage avec son animal de compagnie font aujourd'hui partie intégrante de la médecine préventive. Une bonne communication avec le propriétaire sur les risques encourus, les moyens de prévention et la réglementation permettent de limiter ces risques. Il est aussi important de prévenir les propriétaires que les démarches à effectuer pour que leur animal soit en règle peuvent prendre plusieurs mois et qu'il faut donc s'y prendre à l'avance. Les réglementations peuvent changer d'une année à l'autre vis-à-vis de l'importation d'animaux de compagnie, il est donc judicieux pour les propriétaires de se renseigner également auprès des gouvernements des pays de destination
Alternatives à la castration à vif du porcelet
No full textNational audiencePiglets’ castration, an age-old procedure to prevent boar taint in meat and aggression, is now at the centre of animal welfare debates. French legislation has banned castration without pain management from January 1st, 2022, prompting the development of new methods. Pain management protocols, including analgesia and local anaesthesia, have been tested and implemented on farms following staff training. However, surgical castration remains invasive and time-consuming. It is also a costly technique because, in addition to the cost of labour and products required for pain management, castrated animals have poorer feed conversion ratios than entire male pigs. For this reason, the rearing of entire male pigs has developed considerably in recent years, also thanks to the acquisition of knowledge on how to limit the rate of malodorous carcasses in rearing practices (feeding, comfort, cleanliness and animal health) and advances in genetics with the selection of “odourless” boars. Finally, immunocastration, which consists of vaccinating pigs against GnRH, is a highly effective method of controlling sexual odours in entire male pig carcasses. It offers a number of benefits, particularly in terms of carcase scent and meat quality, but requires rigorous management.La castration des porcelets, pratique séculaire visant à prévenir les odeurs sexuelles dans la viande et l’agressivité, est aujourd’hui au cœur de débats sur le bien-être animal. La réglementation française a interdit la castration à vif depuis le 1 er janvier 2022, poussant à développer de nouvelles méthodes. Des protocoles de prise en charge de la douleur, incluant analgésie et anesthésie locale, ont été testés et mis en place dans les élevages, après formation du personnel. Toutefois, la castration chirurgicale reste invasive et chronophage. C’est aussi une technique coûteuse, car, au-delà du coût de la main-d’œuvre et des produits nécessaires à la gestion de la douleur, les animaux castrés ont des indices de conversion alimentaire dégradés en comparaison à ceux des porcs mâles entiers. C’est pourquoi l’élevage de mâles entiers s’est beaucoup développé ces dernières années, grâce également à l’acquisition de connaissances visant à limiter le taux de carcasses odorantes dans les pratiques de l’élevage (alimentation, confort, propreté et santé des animaux) et aux progrès de la génétique, avec la sélection de verrats « sans odeur ». La détection des carcasses odorantes reste, malgré tout, un impératif à l’abattoir. Enfin, l’immunocastration, qui consiste à vacciner les porcs contre la GnRH, est une méthode très efficace pour lutter contre les odeurs sexuelles dans les carcasses de porcs mâles entiers. Elle offre de nombreux avantages, notamment en termes de taux de carcasses odorantes et de qualité de viande, mais elle nécessite une gestion rigoureuse
A novel in vitro system for simultaneous infections with hepatitis B, C, D and E viruses
No full textInternational audienc
Insight into the tick neurosecretory system
No full textInternational audienceNeurosecretory cells (NSC) are defined as specialized neurons that produce and release chemicalmessengers into the bloodstream to target distant tissues. Although, it seems that tick andinsect nervous systems have developed convergently, as of today the information about tickneurosecretory system along its releasing sites remains literally a “black box”. In presented workwe used specific antibodies against different classes of neuropeptides to reveal completely novellateral and medial clusters of peptidergic NSC in the anterior protocerebrum of Ixodes ricinussynganglion. On one hand, each of these NSC, form a rich axonal network on the dorso-lateralsurface of the synganglion, while on the other hand also send their axons into nearly all internallobes of this organ. Immunogold transmission electron microscopy confirmed that surface axonsof these cells terminate within the dorsal perineurium and release the neuropeptides towards anacellular neurilemma layer, that faces the circularly fluid, the haemolymph. We also found that axonterminals of both lateral and medial NSC are sensitive to acetylcholine (ACh) neurotransmitter asthey express type A and B muscarinic acetylcholine receptors, respectively. Injection of 100 nLwater into unfed I. ricinus female haemocoel intensified the fluorescent neuropeptide signal in theseaxon terminals, while the same volume containing 10 μM ACh had a significantly reduced effect.Here, we hypothesize that increased fluorescence is associated with accelerated neuropeptidesynthesis and subsequent transport to axon terminals as a consequence of sensing the changesin the haemolymph volume. On the other hand, a decreased fluorescent signal indicates that AChmediates release of these neuropeptides that act as hormones for the regulation of osmoregulatoryor other physiological processes. Based on these results we propose a unique model of hormonalacetylcholine-triggered released of peptide hormones in ticks
Les instances nationales dans le domaine de l’utilisation des animaux à des fins scientifiques
No full textInternational audienceIn France, the regulation of the use of animals for scientific purposes is mainly overseen by two ministries: the Ministry in charge of Higher Education and Research (MESR) and the Ministry in charge of Agriculture (MASAF). They work closely together to develop and implement, along with other ministries and bodies, the regulatory provisions designed to ensure that the use of animals for scientific purposes is carried out in compliance with the ethical principles and legislation in force, in this case European Directive 2010/63/EU transposed into the Rural Code in the form of Decree 2013- 118 and its Orders of February 2013. The two ministries rely on the opinions of the National Commission for the Protection of Animals Used for Scientific Purposes (known as the ‘CNEA’) and the National Committee for Ethical Reflection on Animal Experimentation (CNREEA), which reports to the CNEA.En France, la réglementation concernant l’utilisation des animaux à des fins scientifiques est principalement supervisée par deux ministères : le ministère en charge de l’Enseignement Supérieur et de la Recherche (MESR) et le ministère en charge de l’Agriculture (MASAF). Ils travaillent en étroite collaboration pour élaborer et mettre en œuvre, avec d’autres ministères et organismes, les dispositions réglementaires visant à garantir que l’utilisation des animaux à des fins scientifiques est réalisée dans le respect des principes éthiques et de la législation en vigueur, en l’occurrence la directive européenne 2010/63/EU transposée dans le Code rural sous forme du décret 2013- 118 et ses arrêtés de février 2013. Les deux ministères s’appuient sur les avis de la Commission nationale pour la protection des animaux utilisés à des fins scientifiques (dite « CNEA ») et du Comité national de réflexion éthique sur l’expérimentation animale (CNREEA) qui est placé auprès de la CNEA
Strain phylogroup and environmental constraints shape Escherichia coli dynamics and diversity over a 20-year human gut time series
No full textInternational audienceEscherichia coli is an increasingly antibiotic-resistant opportunistic pathogen. Few data are available on its ecological and evolutionary dynamics in its primary commensal niche, the vertebrate gut. Using Illumina and/or Nanopore technologies, we sequenced whole genomes of 210 E. coli isolates from 22 stools sampled during a 20-year period from a healthy man (ED) living in Paris, France. All phylogroups, except C, were represented, with a predominance of B2 (34.3%), followed by A and F (19% each) phylogroups. Thirty-five clones were identified based on their haplogroup and pairwise genomic single nucleotide polymorphism distance and classified in three phenotypes according to their abundance and residence time: 25 sub-dominant/transient (52 isolates), five dominant/transient (48 isolates) and five dominant/resident (110 isolates). Four over five dominant/resident clones belonged to B2 and closely related F phylogroups, whereas sub-dominant/transient clones belonged mainly to B1, A and D phylogroups. The long residence times of B2 clones seemed to be counterbalanced by lower colonization abilities. Clones with larger within-host frequency persisted for longer. By comparing ED strain genomes to a collection of commensal E. coli genomes from 359 French individuals, we identified ED-specific genomic properties including an enrichment in genes involved in a metabolic pathway (mhp cluster) and the presence of a very rare antiviral defense island. The E. coli colonization within the gut microbiota was shaped by both the intrinsic properties of the strain lineages, in particular longer residence of phylogroup B2, and the environmental constraints such as diet or phages
Protocol to study the impact of breast cancer on colonization resistance of mouse microbiota using network node manipulation
No full textInternational audienceNetwork analysis is a powerful tool for investigating complex interactions between different microbial taxa within a community. We present a protocol to study the gut microbial community in a mouse model of breast cancer using a network-based approach. Here, we describe the procedures for tumor cell production and inoculation and 16S rRNA data processing. We then detail steps for constructing co-occurrence networks based on correlations between microbial abundances
Impedance-based method for the quantification of infectious SARS-CoV-2
No full textInternational audienceSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiologic agent involved in the coronavirus disease 2019 (COVID-19) pandemic. The development of infectious titration methods is crucial to provide data for a better understanding of transmission routes, as well as to validate the efficacy of inactivation treatments. Nevertheless, the low-throughput analytical capacity of traditional methods may be a limiting factor for a large screening of samples. The aim of the study was to develop a Real-Time Cell Analysis (RTCA) assay based on the measurement of cell impedance to quantify infectious SARS-CoV-2. The kinetics of cell impedance showed a virus-specific Cell Index (CI) drop. This enabled the correlation between viral concentrations and time at which a 50 % drop in CI values was observed (tCI50), with establishment of a standard curve. In parallel, the improved Spearman and Kärber method was used to quantify infectious titer since the virus-induced CI drop is correlated to the Cytopathic Effect. The estimated uncertainty was respectively 0.57, 0.36, and 0.26 log10 with 4, 8, and 16 wells per dilution. Thus, the RTCA assay is a powerful tool with a greatly simplified workflow for effective risk assessment in the field of food and environmental virology