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[hal-04303778] Characterization of particles exhaled by swine infected with an Influenza virus
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Lyes Ait Ali Yahia) 23 Nov 2023
https://hal.u-pec.fr/hal-04303778
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[hal-04411441] Use of porcine intestinal organoids to study the transmissible gastroenteritis virus
To date, host-virus interactions have been studied mainly in cell cultures and/or animal models. These approaches come up against two problems: i) methodological, usually related to using immortalized cell lines, which can differ greatly from the target cells of the virus, and ii) ethical, related to experimenting with animals, which can induce varying degrees of symptoms and cause suffering and death. The recent development of organoids has made it possible to develop ex vivo models whose experimental conditions are significantly closer to physiological conditions. Using organoids makes it possible to plan to decrease animal experimentation greatly, in line with the 3Rs principle (Reduction, Refinement, Replacement), and each animal can potentially produce thousands of organoids from different tissues. The Viral Genetics and Biosafety Unit applies the porcine organoid system developed locally as part of the PigOrg project (of INRAE, ANSES and INSERM, funded by the Carnot Agrifood Transition Institute) to models of enteric coronavirosis in piglets, which has a strong impact on the pig industry. Here, we used the porcine transmissible gastroenteritis virus (TGEv) as a model, for which several strains of varying virulence exist and which can be cultivated on immortalized cells, to establish protocols of infections of different organoids (jejunum, duodenum, and ileum). Infections seem more effective for the jejunum than for the duodenum or ileum, and for viruses isolated on cells than on organ homogenate. This organoid system, which connects in vitro and in vivo conditions, will open novel and original perspectives into understanding the physiopathology of virus infections, especially deciphering hostpathogen interactions, without always needing to rely on extensive animal experiments.
ano.nymous@ccsd.cnrs.fr.invalid (Maud Contrant) 23 Jan 2024
https://hal.science/hal-04411441
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[hal-04158032] Expérimentation de vaccination des canards mulards en élevage contre un virus influenza aviaire hautement pathogène A(H5N1) clade 2.3.4.4b
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Béatrice Grasland) 10 Jul 2023
https://hal.inrae.fr/hal-04158032
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[hal-04229569] The Smallest Infectious Substructure Encoding the Prion Strain Structural Determinant Revealed by Spontaneous Dissociation of Misfolded Prion Protein Assemblies
It is commonly accepted that the prion replicative propensity and strain structural determinant (SSD) are encoded in the fold of PrPSc amyloid fibril assemblies. By exploring the quaternary structure dynamicity of several prion strains, we revealed that all mammalian prion assemblies exhibit the generic property of spontaneously generating two sets of discreet infectious tetrameric and dimeric species differing significantly by their specific infectivity. By using perturbation approaches such as dilution and ionic strength variation, we demonstrated that these two oligomeric species were highly dynamic and evolved differently in the presence of chaotropic agents. In general, our observations of seven different prion strains from three distinct species highlight the high dynamicity of PrPSc assemblies as a common and intrinsic property of mammalian prions. The existence of such small infectious PrPSc species harboring the SSD indicates that the prion infectivity and the SSD are not restricted only to the amyloid fold but can also be encoded in other alternative quaternary structures. Such diversity in the quaternary structure of prion assemblies tends to indicate that the structure of PrPSc can be divided into two independent folding domains: a domain encoding the strain structural determinant and a second domain whose fold determines the type of quaternary structure that could adopt PrPSc assemblies.
ano.nymous@ccsd.cnrs.fr.invalid (Jan Bohl) 23 Oct 2023
https://hal.science/hal-04229569
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[hal-04174029] Flying syringes for emerging enzootic virus screening: proof of concept for the devlopment of noninvasive xenosurveillance tools based on Tsetse flies
Pathogen transfers between wild and domestic animals and between animals and humans are increasing. Their dramatic consequences for public and veterinary health as well as for conservation call for innovative and user-friendly methods for pathogen surveillance in wildlife. Xenosurveillance, a method based on the use of invertebrates (e.g., mosquitoes, hematophagous flies, leeches, cadaveric arthropods) to sample animal tissues (e.g., blood) and the associated pathogens, is one of these tools. Previously, we demonstrated that hematophagous flies, such as tsetse flies, could be useful to detect and identify the etiological agents of malaria in a diverse range of mammals in Gabon. However, we did not assess whether this method can be also used to detect viruses. In the present study, we experimentally fed tsetse flies (Glossina fuscipes fuscipes) rabbit blood containing different viruses of medical or veterinary importance (Zika, Dengue, Chikungunya, African swine fever, Bluetongue, and peste des petits ruminants viruses). Then, we used quantitative PCR (i) to determine for how long viral nucleic acid fragments remained detectable in the tsetse midgut during blood digestion and (ii) to compare two blood meal preservation methods (i.e., FTA cards and RNAlater solution) tested using tsetse flies engorged with blood and dengue-2 virus. All viruses remained detectable for 6 days after feeding, although the detection probability significantly decreased over time. FTA cards and RNAlater solution gave similar results in terms of virus detection. Our results demonstrate that xenosurveillance using blood-engorged tsetse flies is a valuable tool to track and survey viruses in wildlife in Sub-Saharan Africa.
ano.nymous@ccsd.cnrs.fr.invalid (Adeline Valente) 25 Sep 2023
https://hal.science/hal-04174029
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[hal-04149717] Combining two genetic sexing strains allows sorting of non-transgenic males for Aedes genetic control
Chemical control of disease vectoring mosquitoes Aedes albopictus and Aedes aegypti is costly, unsustainable, and increasingly ineffective due to the spread of insecticide resistance. The Sterile Insect Technique is a valuable alternative but is limited by slow, error-prone, and wasteful sex-separation methods. Here, we present four Genetic Sexing Strains (two for each Aedes species) based on fluorescence markers linked to the m and M sex loci, allowing for the isolation of transgenic males. Furthermore, we demonstrate how combining these sexing strains enables the production of non-transgenic males. In a mass-rearing facility, 100,000 first instar male larvae could be sorted in under 1.5 h with an estimated 0.01-0.1% female contamination on a single machine. Cost-efficiency analyses revealed that using these strains could result in important savings while setting up and running a mass-rearing facility. Altogether, these Genetic Sexing Strains should enable a major upscaling in control programmes against these important vectors.
ano.nymous@ccsd.cnrs.fr.invalid (Célia Lutrat) 04 Jul 2023
https://hal.science/hal-04149717
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[hal-04431895] What about a transmission of SARS-CoV-2 through a viral biofilm?
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ano.nymous@ccsd.cnrs.fr.invalid (M.-I. Thoulouze) 01 Feb 2024
https://hal.inrae.fr/hal-04431895
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[hal-04429897] Et si le SARS-CoV-2 se transmettait sous forme de biofilm viral ?
[...]
ano.nymous@ccsd.cnrs.fr.invalid (M.-I. Thoulouze) 01 Feb 2024
https://hal.inrae.fr/hal-04429897
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[hal-04320100] Conception d'un banc expérimental pour l'étude des émissions d'aérosols chez le porc
Dans ce travail, nous avons conçu et testé un premier banc expérimental pour l'estimation des exhalaisons d'aérosols chez le porc. Ce nouveau banc, modulable et transportable, a été adapté à la manipulation dans des installations expérimentales protégées de niveau de biosécurité A3. Il permet de réaliser des mesures d'émission dans un environnement contrôlé. Outre la caractérisation des bioaérosols produits par l'animal, ce banc permet de contrôler la concentration en particules en utilisant un Aerosol Particle sizer (APS). Une première caractérisation pour déterminer le taux d'épuration et de dépôt du banc a été réalisée ainsi que des primomesures en animalerie sur des porcs exempts d'organismes pathogènes spécifiés de l'espèce ou EOPS.
ano.nymous@ccsd.cnrs.fr.invalid (A Boulbair) 04 Dec 2023
https://hal.u-pec.fr/hal-04320100
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[hal-04067308] Vector competence of sterile male Glossina fuscipes fuscipes for Trypanosoma brucei brucei: implications for the implementation of the sterile insect technique in a sleeping sickness focus in Chad
Background Human African trypanosomiasis (HAT) is a neglected tropical disease caused by Trypanosoma brucei gambiense transmitted by tsetse flies in sub-Saharan West Africa. In southern Chad the most active and persistent focus is the Mandoul focus, with 98% of the reported human cases, and where African animal trypanosomosis (AAT) is also present. Recently, a control project to eliminate tsetse flies ( Glossina fuscipes fuscipes ) in this focus using the sterile insect technique (SIT) was initiated. However, the release of large numbers of sterile males of G. f. fuscipes might result in a potential temporary increase in transmission of trypanosomes since male tsetse flies are also able to transmit the parasite. The objective of this work was therefore to experimentally assess the vector competence of sterile males treated with isometamidium for Trypanosoma brucei brucei . Methods An experimental infection was set up in the laboratory, mimicking field conditions: the same tsetse species that is present in Mandoul was used. A T. b. brucei strain close to T. b. gambiense was used, and the ability of the sterile male tsetse flies fed on blood with and without a trypanocide to acquire and transmit trypanosomes was measured. Results Only 2% of the experimentally infected flies developed an immature infection (midgut) while none of the flies developed a metacyclic infection of T. b. brucei in the salivary glands. We did not observe any effect of the trypanocide used (isometamidium chloride at 100 mg/l) on the development of infection in the flies. Conclusions Our results indicate that sterile males of the tested strain of G. f. fuscipes were unable to cyclically transmit T. b. brucei and might even be refractory to the infection. The data of the research indicate that the risk of cyclical transmission of T. brucei by sterile male G. f. fuscipes of the strain colonized at IAEA for almost 40 years appears to be small. Graphical Abstract
ano.nymous@ccsd.cnrs.fr.invalid (Mahamat Hissene Mahamat) 13 Apr 2023
https://hal.inrae.fr/hal-04067308
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[hal-04107725] Investigation of the Genus Flavobacterium as a Reservoir for Fish-Pathogenic Bacterial Species: the Case of Flavobacterium collinsii
Bacteria of the genus Flavobacterium are recovered from a large variety of environments. Among the described species, Flavobacterium psychrophilum and Flavobacterium columnare cause considerable losses in fish farms. Alongside these well-known fish-pathogenic species, isolates belonging to the same genus recovered from diseased or apparently healthy wild, feral, and farmed fish have been suspected to be pathogenic. Here, we report the identification and genomic characterization of a Flavobacterium collinsii isolate (TRV642) retrieved from rainbow trout spleen. A phylogenetic tree of the genus built by aligning the core genome of 195 Flavobacterium species revealed that F. collinsii stands within a cluster of species associated with diseased fish, the closest one being F. tructae, which was recently confirmed as pathogenic. We evaluated the pathogenicity of F. collinsii TRV642 as well as of Flavobacterium bernardetii F-372T, another recently described species reported as a possible emerging pathogen. Following intramuscular injection challenges in rainbow trout, no clinical signs or mortalities were observed with F. bernardetii. F. collinsii showed very low virulence but was isolated from the internal organs of survivors, indicating that the bacterium is able to survive inside the host and may provoke disease in fish under compromised conditions such as stress and/or wounds. Our results suggest that members of a phylogenetic cluster of fish-associated Flavobacterium species may be opportunistic fish pathogens causing disease under specific circumstances. IMPORTANCE Aquaculture has expanded significantly worldwide in the last decades and accounts for half of human fish consumption. However, infectious fish diseases are a major bottleneck for its sustainable development, and an increasing number of bacterial species from diseased fish raise a great concern. The current study revealed phylogenetic associations with ecological niches among the Flavobacterium species. We also focused on Flavobacterium collinsii, which belongs to a group of putative pathogenic species. The genome contents revealed a versatile metabolic repertoire suggesting the use of diverse nutrient sources, a characteristic of saprophytic or commensal bacteria. In a rainbow trout experimental challenge, the bacterium survived inside the host, likely escaping clearance by the immune system but without provoking massive mortality, suggesting opportunistic pathogenic behavior. This study highlights the importance of experimentally evaluating the pathogenicity of the numerous bacterial species retrieved from diseased fis
ano.nymous@ccsd.cnrs.fr.invalid (Bo-Hyung Lee) 05 Jun 2023
https://hal.science/hal-04107725
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[anses-04123704] Evaluation of early single dose vaccination on swine influenza A virus transmission in piglets: From experimental data to mechanistic modelling
Swine influenza A virus (swIAV) is a major pathogen affecting pigs with a huge economic impact and potentially zoonotic. Epidemiological studies in endemically infected farms permitted to identify critical factors favoring on-farm persistence, among which maternally-derived antibodies (MDAs). Vaccination is commonly practiced in breeding herds and might be used for immunization of growing pigs at weaning. Althoughinterference between MDAs and vaccination was reported in young piglets, its impact on swIAV transmission was not yet quantified. To this aim, this study reports on a transmission experiment in piglets with or without MDAs, vaccinated with a single dose injection at four weeks of age, and challenged 17 days post-vaccination. To transpose small-scale experiments to real-life situation, estimated parameters were used in a simulation tool to assess their influence at the herd level. Based on a thorough follow-up of the infection chain during the experiment, the transmission of the swIAV challenge strain was highly dependent on the MDA status of the pigs when vaccinated. MDA-positive vaccinated animals showed a direct transmission rate 3.6-fold higher than the one obtained in vaccinated animals without MDAs, estimated to 1.2. Vaccination nevertheless reduced significantly the contribution of airborne transmission when compared with previous estimates obtained in unvaccinated animals. The integration of parameter estimates in a large-scale simulation model, representing a typical farrow-to-finish pig herd, evidenced an extended persistence of viral spread when vaccination of sows and single dose vaccination of piglets was hypothesized. When extinction was quasi-systematic at year 5 post-introduction in the absence of sow vaccination but with single dose early vaccination of piglets, the extinction probability fell down to 33% when batch-to-batch vaccination was implemented both in breeding herd and weaned piglets. These results shed light on a potential adverse effect of single dose vaccination in MDA-positive piglets, which might lead to longer persistence of the SwIAV at the herd level.
ano.nymous@ccsd.cnrs.fr.invalid (Mathieu Andraud) 09 Jun 2023
https://anses.hal.science/anses-04123704
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[hal-04320097] Caractérisation des particules exhalées par des porcs infectes par un virus influenza porcin
L’objectif principal de ce travail expérimental est la caractérisation physique et biologique des exhalaisons de modèles porcins infectés par un virus influenza porcin. Ces expérimentations sont conduites sur le site de Ploufragan-Plouzané-Niort de l’ANSES dans l’animalerie expérimentale de niveau de biosécurité A3. Un banc expérimental a été développé de manière à pouvoir isoler, collecter et caractériser les émissions respiratoires. La description technique du banc, la procédure expérimentale employée ainsi que des résultats préliminaires de caractérisation physique sont présentés.
ano.nymous@ccsd.cnrs.fr.invalid (A Boulbair) 04 Dec 2023
https://hal.u-pec.fr/hal-04320097
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[anses-04123731] Plasmid DNA Prime/Protein Boost Vaccination against Campylobacter jejuni in Broilers: Impact of Vaccine Candidates on Immune Responses and Gut Microbiota
Campylobacter infections, traced to poultry products, are major bacterial foodborne zoonoses, and vaccination is a potential solution to reduce these infections. In a previous experimental trial using a plasmid DNA prime/recombinant protein boost vaccine regimen, two vaccine candidates (YP437 and YP9817) induced a partially protective immune response against Campylobacter in broilers, and an impact of the protein batch on vaccine efficacy was suspected. This new study was designed to evaluate different batches of the previously studied recombinant proteins (called YP437A, YP437P and YP9817P) and to enhance the immune responses and gut microbiota studies after a C. jejuni challenge. Throughout the 42-day trial in broilers, caecal Campylobacter load, specific antibodies in serum and bile, the relative expression of cytokines and β-defensins, and caecal microbiota were assessed. Despite there being no significant reduction in Campylobacter in the caecum of vaccinated groups, specific antibodies were detected in serum and bile, particularly for YP437A and YP9817P, whereas the production of cytokines and β-defensins was not significant. The immune responses differed according to the batch. A slight change in microbiota was demonstrated in response to vaccination against Campylobacter. The vaccine composition and/or regimen must be further optimised.
ano.nymous@ccsd.cnrs.fr.invalid (Noémie Gloanec) 09 Jun 2023
https://anses.hal.science/anses-04123731
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[anses-04350409] Evaluation of Two Recombinant Protein-Based Vaccine Regimens against Campylobacter jejuni: Impact on Protection, Humoral Immune Responses and Gut Microbiota in Broilers
Campylobacter infections in humans are traced mainly to poultry products. While vaccinating poultry against Campylobacter could reduce the incidence of human infections, no vaccine is yet available on the market. In our previous study using a plasmid DNA prime/recombinant protein boost vaccine regimen, vaccine candidate YP437 induced partial protective immune responses against Campylobacter in broilers. In order to optimise vaccine efficacy, the vaccination protocol was modified using a protein prime/protein boost regimen with a different number of boosters. Broilers were given two or four intramuscular protein vaccinations (with the YP437 vaccine antigen) before an oral challenge by C. jejuni during a 42-day trial. The caecal Campylobacter load, specific systemic and mucosal antibody levels and caecal microbiota in the vaccinated groups were compared with their respective placebo groups and a challenge group (Campylobacter infection only). Specific humoral immune responses were induced, but no reduction in Campylobacter caecal load was observed in any of the groups (p > 0.05). Microbiota beta diversity analysis revealed that the bacterial composition of the groups was significantly different (p ≤ 0.001), but that vaccination did not alter the relative abundance of the main bacterial taxa residing in the caeca. The candidate vaccine was ineffective in inducing a humoral immune response and therefore did not provide protection against Campylobacter spp. infection in broilers. More studies are required to find new candidates.
ano.nymous@ccsd.cnrs.fr.invalid (Noémie Gloanec) 18 Dec 2023
https://anses.hal.science/anses-04350409
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[hal-04343291] Potential of Marine Strains of Pseudoalteromonas to Improve Resistance of Juvenile Sea Bass to Pathogens and Limit Biofilm Development
The European sea bass (Dicentrarchus labrax), one of the most produced marine fish species in Europe, is acutely vulnerable to multiple infectious hazards. In this study, we investigated the potential probiotic effect of some marine Pseudoalteromonas bacterial strains against two major pathogens of this species, Vibrio harveyi and the nervous necrosis virus (NNV), and examined their antibiofilm effect. Impregnation phase was done by repeated immersion of juvenile’s sea bass during 8 to 12 weeks in seawater containing the probiotic candidates at a concentration of 106 CFU/mL. Four candidates were tested: (1) a combination of two strains producing antimicrobial compounds, hCg-42 and hOe-125; (2) strain 3J6, with known antibiofilm properties; (3) strain RA15, from the same genus, but with no identified probiotic effect; and (4) a control group without probiotics. At the end of the impregnation phase, fish underwent an infection challenge with V. harveyi or with a pathogenic strain of NNV and mortality was monitored. For the V. harveyi challenge, improved survival rates of 10 and 25% were obtained for the RA15 and the mix hCg-42 + hOe-125-impregnated groups, respectively. For the NNV challenge, no significant benefic effect of the probiotics on infection kinetics or cumulative mortality was observed. At the end of the impregnation phase, the maximal thickness of biofilm was significantly lower in the 3J6, double strain, and RA15 groups, compared with the non-impregnated control group. This study highlights the interesting probiotic potential of marine bacteria to limit mortalities induced by bacterial pathogens as well as biofilm development.
ano.nymous@ccsd.cnrs.fr.invalid (Alexandra Rahmani) 22 Feb 2024
https://hal.science/hal-04343291
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[anses-04311437] Adaptation of the ASFV-989 live attenuated virus on continuous cell line, a step forward to become a vaccine candidate
African swine fever since its reintroduction in Georgia in 2007 has spread across Europe, Southeast Asia and Caribbean. ANSES Ploufragan laboratory has recently developed an experimental vaccine candidate, ASFV-989, by thermo-attenuation of the highly virulent pandemic ASFV strain Georgia 2007/1. ASFV-989 has proven to be safe and highly efficacious in challenge studies using the parental strain, either by intramuscular (IM) or oronasal (ON) routes. The next step to pass for further vaccine development is the adaptation of the ASFV-989-PAM grown on porcine alveolar macrophages, to a continuous cell line. Here, we will present data demonstrating the successful adaptation of ASFV-989 to grow on Swine Testis (ST) cells, with a replication kinetics similar to the ASFV-989-PAM. In vivo, 21 specific pathogen free pigs inoculated with the ASFV-989-ST strain, either IM (13) or ON (8), exhibited only a few cases of hyperthermia from D4 to D9 post-inoculation (pi) and a small decrease of growth performances during the first week pi. Animals immunized with the ASFV-989-ST strain showed a low vaccine viremia between D3 to D27pi in all IM inoculated and in 7/8 ON inoculated pigs. ASFV specific antibodies were detected from D11pi, and ASFV specific cell mediated response at D13pi. In pigs immunized with the ASFV-989-ST strain then challenged 4 weeks later with the Georgia 2007/1 strain, 1/6 pigs immunized IM developed ASF symptoms from D6 post challenge (pc) and had to be euthanatized at D8pc, when the 5 other pigs only displayed late and light hyperthermia. Only one ON immunized pig displayed hyperthermia during one day pc. In contrast, the 3 non-immunized pigs presented a fatal evolution in less than 1 week. In ASFV-989-ST immunized pigs, we saw a strong control of the Georgia strain viremia compared to non-immunized pigs. Georgia strain viremia was detected in 5/6 pigs immunized IM, and only in 1/6 pigs (1 time point) for the ON immunized pigs. In summary, the ASFV-989-ST presented a very good safety and efficacy for ON immunization. For IM immunization, the ASF-989-ST was safer than the original ASFV-989-PAM but less efficient, probably due to a suboptimal dose. Therefore, the ASFV-989-ST strain looks like a very good vaccine candidate that can be administered oronasally, a critical attribute for potential vaccination of wild boars populations. Further studies are needed to evaluate its stability and increase its efficacy for IM pig vaccination.
ano.nymous@ccsd.cnrs.fr.invalid (Marie-Frédérique Le Potier) 28 Nov 2023
https://anses.hal.science/anses-04311437
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[anses-04472181] Caractérisation d’un nouveau picornavirus isolé de larves de daurades (Sparus aurata) cliniquement atteintes
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Lénaïg Louboutin) 22 Feb 2024
https://anses.hal.science/anses-04472181
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[anses-04509732] Bacteroides fragilis : un probiotique nouvelle génération pour maîtriser Salmonella dans la filière porcine ?
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Valérie Rose) 18 Mar 2024
https://anses.hal.science/anses-04509732
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[anses-04228409] Controlled Experimental Infection in Pigs with a Strain of Yersinia enterocolitica Harboring Genetic Markers for Human Pathogenicity: Colonization and Stability
Yersinia enterocolitica (Ye) is one of the major causes of foodborne zoonosis. The BT4/O:3 bioserotype is most commonly isolated in human infections. Pigs are considered the main reservoir of Ye, and hence, understanding the dynamics of infection by this pathogen at the individual and group levels is crucial. In the present study, an experimental model was validated in Large White pigs infected with a BT4/O:3 strain. This study showed that Ye contamination in pigs may occur via the introduction of the bacteria not only by mouth but also by snout, with a colonization process consisting of three periods corresponding to three contamination statuses of pigs: P1, corresponding to the 24 h following ingestion or inhalation of Ye with the appearance of bacteria in tonsils or in feces; P2, from 2 days postinoculation (dpi), corresponding to expansion of Ye and colonization of the digestive system and extraintestinal organs associated with an IgG serological response; and P3, after 21 dpi, corresponding to regression of colonization with intermittent Ye detection in tonsils and feces. Although the inoculated strain persisted up to 56 dpi in all pigs, genetic variations with the loss of the gene yadA (a gene involved in human infection) and the emergence of two new multilocus variable-number tandemrepeat analysis (MLVA) profiles were observed in 33% of the 30 isolates studied. This experimental infection model of pigs by Ye provides new insights into the colonization steps in pigs in terms of bacterial distribution over time and bacterial genetic stability.
ano.nymous@ccsd.cnrs.fr.invalid (Emilie Esnault) 04 Oct 2023
https://anses.hal.science/anses-04228409
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[anses-04471399] Evaluation de la virémie et des capacités de transmission des vaccins vivants atténués contre le syndrome dysgénésique et respiratoire porcin pour une meilleure prévention des risques de recombinaison entre souches vaccinales
L’infection par les virus du syndrome dysgénésique et respiratoire porcin de type 1 (SDRPv1) ou 2 (SDRPv2), induit des pertes économiques considérables pour la production porcine. Le contrôle du SDRP fait largement appel aux vaccins vivants atténués (”modified live vaccine” contre les virus de type 1 (MLV1) ou 2 (MLV2)). Récemment, des souches recombinantes d’origine vaccinale (MLV1) ont été détectées. Ces recombinaisons entre souches vaccinales peuvent apparaître lorsque qu’un animal, virémique pour une souche vaccinale, est vacciné ou infecté (par transmission) par une autre souche vaccinale. Afin de prévenir ces recombinaisons, l’objectif de cette étude était d’évaluer la virémie (durée et charge virale) et les capacités de transmission des quatre MLV1 contre le SDRP autorisés en France (Porcilis PRRS (PORCI), Unistrain PRRS (UNI), Ingelvac PRRSFlex EU (FLEX), Suvaxyn PRRS MLV (SUV)), comparées avec celles d’un MLV2, généralement plus réplicatif. Pour cela, 5 groupes de 6 porcelets ont été vaccinés puis mis en contact avec des porcelets sentinelles. Les charges génomiques vaccinales ont été quantifiées deux fois par semaine par qRT-PCR pour suivre la virémie vaccinale et estimer les paramètres de transmission de chaque souche par modélisation mathématique. Les résultats ont montré une virémie longue pour PORCI, UNI et le MLV2 (respectivement, 50, 53 et 50 jours) et courte pour SUV et FLEX (44 et 39 jours respectivement). Les plus faibles charges virales ont été quantifiées avec FLEX et les plus élevées avec le MLV2 et UNI. Aucune transmission n’a été observée avec FLEX (taux de transmission β = 7,7.10 -7) alors que le taux de transmission a été estimé élevé pour UNI (4,5.10 -2 ) et MLV2 (3,2.10 -2 ) et estimé faible pour PORCI et SUV (6,1.10 -3 pour les 2 vaccins). Les caractéristiques virologiques de chaque MLV1 doivent être prises en considération dans les protocoles vaccinaux pour prévenir les risques de recombinaison entre souches vaccinales.
ano.nymous@ccsd.cnrs.fr.invalid (Sophie Mahé) 21 Feb 2024
https://anses.hal.science/anses-04471399
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[anses-04311332] Selection of antibiotic resistance in pigs after exposure to feed cross-contaminated with oxytetracycline
Due to possible cross-contamination of animal feedstuff with antibiotics, food-producing animals may be exposed to undesirable low concentrations of antimicrobials. These sub-therapeutic levels of antibiotics can lead to the selection of resistant bacteria in the animal gut. The goal of this study was to assess, through analysis of the faeces of treated and control pigs, the risk of resistant E. coli being selected after daily exposure for three weeks to feed contaminated with oxytetracycline at 1% of the therapeutic dose. Liquid Chromatography coupled to tandem Mass Spectrometry was used to determine the oxytetracycline concentrations in faecal samples. In the treated group, concentrations were in the range of 4481.9-8671.2 µg/kg. In the control group, these concentrations were either below the method's limit of quantification or up to 60.5 µg/kg. After a transient increase in resistance in both groups, microbiological analysis showed that the treated group had a significantly higher oxytetracycline resistance rate by the end of the study than the control group (p < 0.001). Furthermore, the treated animals were found to select co-resistances to nalidixic acid and ampicillin. Finally, at tolerated antibiotic contamination levels of feed, the treated group had a higher proportion of multidrug-resistant isolates at the end of the study than the control one (p < 0.05). The present study demonstrates that, at the tolerated contamination rates, both antimicrobial resistance and multidrug-resistant bacteria can be selected and evidenced in the gut microbiota.
ano.nymous@ccsd.cnrs.fr.invalid (Cristina Santos-Santórum Suárez) 28 Nov 2023
https://anses.hal.science/anses-04311332
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[anses-04395723] Characterization of a New Toti-like Virus in Sea Bass, Dicentrarchus labrax
The European sea bass Dicentrarchus labrax is the main species reared in Mediterranean aquaculture. Its larval stage, which is very sensitive and highly affected by sanitary and environmental conditions, is particularly scrutinized in hatcheries. Recently, a Mediterranean sea bass farm had to deal with an abnormal increase in mortality, especially between 20 and 35 days post-hatching (dph). Biological investigations led to the observation of cytopathic effects on three different fish cell lines after almost 3 weeks of culture at 14 • C in contact with homogenized affected larvae, suggesting the presence of a viral agent. High-throughput sequencing revealed a 6818-nucleotide-long RNA genome with six putative ORFs, corresponding to the organization of viruses belonging to the Totiviridae family. This genome clustered with the newly described and suggested Pistolvirus genus, sharing 45.5% to 37.2% nucleotide identity with other piscine toti-like viruses such as Cyclopterus lumpus toti-like virus (CLuTLV) or piscine myocarditis virus (PMCV), respectively. Therefore, we propose to name this new viral agent sea bass toti-like virus (SBTLV). Specific real-time RT-PCR confirmed the presence of the viral genome in the affected larval homogenate from different production batches and the corresponding cell culture supernatant. Experimental infections performed on sea bass fingerlings did not induce mortality, although the virus could be detected in various organs and a specific immune response was developed. Additional studies are needed to understand the exact involvement of this virus in the mortality observed in hatcheries and the potential associated cofactors.
ano.nymous@ccsd.cnrs.fr.invalid (Lénaïg Louboutin) 15 Jan 2024
https://anses.hal.science/anses-04395723
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[hal-04484150] Experimental study of infection with a new genotype of swine influenza virus that has spread in France and evaluation of vaccine protection
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Céline Deblanc) 29 Feb 2024
https://hal.science/hal-04484150
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[anses-04040798] Research Note: Analysis of immune responses in broilers after vaccination against Campylobacter jejuni
Campylobacter infections traced mainly to poultry products are major bacterial foodborne zoonoses. Among the many control strategies evaluated at primary poultry level to reduce these infections, vaccination could be a solution, but no effective vaccines are available to date. A better understanding of the immune mechanisms involved in protection against Campylobacter would be helpful for designing novel vaccine strategies. The present study was designed to analyze in more depth the immune responses developed in broilers in order to potentially identify which immune parameters may be important for establishing protection against Campylobacter by comparing the immune responses obtained here with those obtained in a previous study performed on vaccinated specific-pathogen-free Leghorn chickens that presented a partial reduction of Campylobacter after experimental challenge. The protection against Campylobacter colonization was evaluated at different time points over 40 d of rearing, by measuring specific IgY levels in serum and IgA antibodies in bile reflecting the systemic and mucosal humoral responses respectively and the relative expressions of 9 cecal immune marker genes (cytokines and antimicrobial peptides), which reflect the innate and cellular immune responses. Despite no reduction of Campylobacter in the cecum, a systemic immune response over time characterized by the production of specific anti-flagellin IgY was observed, in addition to upregulation of the antimicrobial peptide avian b-defensin (AvBD) 12 gene expression in the cecum of vaccinated broilers compared with the placebo group. However, the levels of specific anti-flagellin mucosal IgA antibodies in the bile as well as the relative expression of other cecal cytokines studied was underexpressed in the vaccinated group or similar in both groups.
ano.nymous@ccsd.cnrs.fr.invalid (Noémie Gloanec) 22 Mar 2023
https://anses.hal.science/anses-04040798
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[anses-03966233] High antigenic diversity of serotype 1 infectious bursal disease virus revealed by antigenic cartography
The antigenic characterization of IBDV, a virus that causes an immunosuppressive disease in young chickens, has been historically addressed using cross virus neutralization (VN) assay and antigen-capture enzyme-linked immunosorbent (AC-ELISA). However, VN assay has been usually carried out either in specific antibody negative embryonated eggs, for non-cell culture adapted strains, which is tedious, or on chicken embryo fibroblasts (CEF), which requires virus adaptation to cell culture. AC-ELISA has provided crucial information about IBDV antigenicity, but this information is limited to the epitopes included in the tested panel with a lack of information of overall antigenic view. The present work aimed at overcoming those technical limitations and providing an extensive antigenic landscape based on original cross VN assays employing primary chicken B cells, where no previous IBDV adaptation is required. Sixteen serotype 1 IBDV viruses, comprising both reference strains and documented antigenic variants were tested against eleven chicken post-infectious sera. The VN data were analysed by antigenic cartography, a method which enables reliable high-resolution quantitative and visual interpretation of large binding assay datasets. The resulting antigenic cartography revealed i) the existence of several antigenic clusters of IBDV, ii) high antigenic relatedness between some genetically unrelated viruses, iii) a highly variable contribution to global antigenicity of previously identified individual epitopes and iv) broad reactivity of chicken sera raised against antigenic variants. This study provides an overall view of IBDV antigenic diversity. Implementing this approach will be instrumental to follow the evolution of IBDV antigenicity and control the disease.
ano.nymous@ccsd.cnrs.fr.invalid (Liliana L Cubas-Gaona) 15 Mar 2023
https://anses.hal.science/anses-03966233
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[hal-04172998] Deficiency in hereditary hemorrhagic telangiectasia-associated Endoglin elicits hypoxia-driven heart failure in zebrafish
ABSTRACT Hereditary hemorrhagic telangiectasia (HHT) is a rare genetic disease caused by mutations affecting components of bone morphogenetic protein (BMP)/transforming growth factor-β (TGF-β) signaling in endothelial cells. This disorder is characterized by arteriovenous malformations that are prone to rupture, and the ensuing hemorrhages are responsible for iron-deficiency anemia. Along with activin receptor-like kinase (ALK1), mutations in endoglin are associated with the vast majority of HHT cases. In this study, we characterized the zebrafish endoglin locus and demonstrated that it produces two phylogenetically conserved protein isoforms. Functional analysis of a CRISPR/Cas9 zebrafish endoglin mutant revealed that Endoglin deficiency is lethal during the course from juvenile stage to adulthood. Endoglin-deficient zebrafish develop cardiomegaly, resulting in heart failure and hypochromic anemia, which both stem from chronic hypoxia. endoglin mutant zebrafish display structural alterations of the developing gills and underlying vascular network that coincide with hypoxia. Finally, phenylhydrazine treatment demonstrated that lowering hematocrit/blood viscosity alleviates heart failure and enhances the survival of Endoglin-deficient fish. Overall, our data link Endoglin deficiency to heart failure and establish zebrafish as a valuable HHT model.
ano.nymous@ccsd.cnrs.fr.invalid (Etienne Lelièvre) 28 Jul 2023
https://hal.inrae.fr/hal-04172998
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[hal-04294675] Identification of a pharyngeal mucosal lymphoid organ in zebrafish and other teleosts: Tonsils in fish?
The constant exposure of the fish branchial cavity to aquatic pathogens causes local mucosal immune responses to be extremely important for their survival. Here, we used a marker for T lymphocytes/natural killer (NK) cells (ZAP70) and advanced imaging techniques to investigate the lymphoid architecture of the zebrafish branchial cavity. We identified a sub-pharyngeal lymphoid organ, which we tentatively named "Nemausean lymphoid organ" (NELO). NELO is enriched in T/NK cells, plasma/B cells, and antigen-presenting cells embedded in a network of reticulated epithelial cells. The presence of activated T cells and lymphocyte proliferation, but not V(D)J recombination or hematopoiesis, suggests that NELO is a secondary lymphoid organ. In response to infection, NELO displays structural changes including the formation of T/NK cell clusters. NELO and gill lymphoid tissues form a cohesive unit within a large mucosal lymphoid network. Collectively, we reveal an unreported mucosal lymphoid organ reminiscent of mammalian tonsils that evolved in multiple teleost fish familie
ano.nymous@ccsd.cnrs.fr.invalid (Julien Resseguier) 20 Nov 2023
https://hal.science/hal-04294675
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[hal-04081993] Effects of dietary co-exposure to fungal and herbal functional feed additives on immune parameters and microbial intestinal diversity in rainbow trout (<i>Oncorhynchus mykiss</i>)
Misuse and overuse of antibiotics in aquaculture has proven to be an unsustainable practice leading to increased bacterial resistance. An alternative strategy involves the inclusion of immunostimulants in fish diets, especially fungal and herbal compounds already authorized for human consumption, hence without environmental or public health concerns. In this study, we used a holistic and cross-disciplinary pipeline to assess the immunostimulatory properties of two fungi: Trametes versicolor and Ganoderma lucidum; one herbal supplement, capsaicin in the form of Espelette pepper (Capsicum annuum), and a combination of these fungal and herbal additives on rainbow trout (Oncorhynchus mykiss). We investigated the impact of diet supplementation for 7 weeks on survival, growth performance, cellular, humoral, and molecular immune parameters, as well as the intestinal microbial composition of the fish. Uptake of herbal and fungal compounds influenced the expression of immune related genes, without generating an inflammatory response. Significant differences were detected in the spleen-tlr2 gene expression. Supplementation with herbal additives correlated with structural changes in the fish intestinal microbiota and enhanced overall intestinal microbial diversity. Results demonstrated that the different treatments had no adverse effect on growth performance and survival, suggesting the safety of the different feed additives at the tested concentrations. While the mechanisms and multifactorial interactions remain unclear, this study provides insights not only in regard to nutrition and safety of these compounds, but also how a combined immune and gut microbiota approach can shed light on efficacy of immunostimulant compounds for potential commercial inclusion as feed supplements.
ano.nymous@ccsd.cnrs.fr.invalid (Julia Mougin) 26 Apr 2023
https://ulco.hal.science/hal-04081993
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[hal-04168152] Overexpression of Eimeria tenella Rhoptry Kinase 2 Induces Early Production of Schizonts
Eimeria tenella is an obligate intracellular parasite responsible for avian coccidiosis. Like other apicomplexan parasites, such as Toxoplasma gondii, cell invasion and intracellular development rely on apical organelle content discharge, named micronemes and rhoptries. Some rhoptry (ROP) kinases (ROPK) are key virulence factors in T. gondii. To date, among the 28 ropk genes carried by E. tenella, only two to four were confirmed by proteomic analysis or immunostaining to be expressed at the sporozoite stage. We have previously shown that EtROP1 is implicated in the inhibition of host cell apoptosis by interacting with the cellular p53. This work functionally described the second ROP kinase expressed at the sporozoite stage in E. tenella. EtROP2 is an active kinase that phosphorylates cell substrates of approximately 50 kDa. Its overexpression leads to the shortening of the prepatent period and to the early development of first-generation schizonts. Conduction of RNA sequencing analysis and reverse transcriptase quantitative PCR (RT-qPCR) on the host cell allowed us to identify the mitogen-activated protein kinase (MAPK) pathway and the transcription factor cFos to be upregulated by EtROP2. We also showed by immunofluorescence assay that the active kinase EtROP2 is implicated in the p38 MAPK pathway activation. We established here that EtROP2 activates the p38 MAPK pathway through a direct or indirect phosphorylation, leading to the overexpression of the master transcription factor cFos known to be implicated in E. tenella development. IMPORTANCE Rhoptries are specialized secretory organelles found in zoite stages of apicomplexan parasites. In addition to well-conserved rhoptry neck proteins, their protein consists mostly of kinase proteins, highly divergent from eukaryotic kinases. Some of those kinases are described as major virulence factors in Toxoplasma gondii, secreted into the host cell to hijack signaling pathways. Most of those kinases remain to be characterized in Eimeria tenella. Deciphering their cellular function is a prerequisite to supporting their relevance as a druggable target in development of new means of Eimeria tenella control. Secreted divergent kinases that interact with host cell partners to modulate pathways are good candidates, as they coevolve with their host targets to ensure their function within the host and are less prone to mutations that would lead to drug resistance. The absence of any orthologous kinase in host cells makes these parasite kinases a promising drug target candidate.
ano.nymous@ccsd.cnrs.fr.invalid (Adeline Ribeiro E Silva) 21 Jul 2023
https://hal.inrae.fr/hal-04168152
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[hal-04344510] Gut barrier-microbiota imbalances in early life lead to higher sensitivity to inflammation in a murine model of C-section delivery
Background Most interactions between the host and its microbiota occur at the gut barrier, and primary colonizers are essential in the gut barrier maturation in the early life. The mother–offspring transmission of microorganisms is the most important factor influencing microbial colonization in mammals, and C-section delivery (CSD) is an important disruptive factor of this transfer. Recently, the deregulation of symbiotic host-microbe interactions in early life has been shown to alter the maturation of the immune system, predisposing the host to gut barrier dysfunction and inflammation. The main goal of this study is to decipher the role of the early-life gut microbiota-barrier alterations and its links with later-life risks of intestinal inflammation in a murine model of CSD. Results The higher sensitivity to chemically induced inflammation in CSD mice is related to excessive exposure to a too diverse microbiota too early in life. This early microbial stimulus has short-term consequences on the host homeostasis. It switches the pup’s immune response to an inflammatory context and alters the epithelium structure and the mucus-producing cells, disrupting gut homeostasis. This presence of a too diverse microbiota in the very early life involves a disproportionate short-chain fatty acids ratio and an excessive antigen exposure across the vulnerable gut barrier in the first days of life, before the gut closure. Besides, as shown by microbiota transfer experiments, the microbiota is causal in the high sensitivity of CSD mice to chemical-induced colitis and in most of the phenotypical parameters found altered in early life. Finally, supplementation with lactobacilli, the main bacterial group impacted by CSD in mice, reverts the higher sensitivity to inflammation in ex-germ-free mice colonized by CSD pups’ microbiota. Conclusions Early-life gut microbiota-host crosstalk alterations related to CSD could be the linchpin behind the phenotypic effects that lead to increased susceptibility to an induced inflammation later in life in mice.
ano.nymous@ccsd.cnrs.fr.invalid (M. Barone) 14 Dec 2023
https://hal.inrae.fr/hal-04344510
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[hal-04189068] Modulation of gut microbiota by antibiotics did not affect anhedonia in a high-fat diet-induced model of depression in male mice
Background: Long-term consumption of a high-fat diet (HFD) causes obesity and is a risk factor for depression. The HFD has a significant impact on the gut microbiota, and dysbiosis of the microbiota is now associated with certain psychiatric disorders such as anxiety and depression. We aimed to investigate whether modulation by antibiotic treatment of the composition of the gut microbiota in diet-induced obese (DIO) C57BL/6J male mice has an impact on depressive-like behaviour. Methods: In this study, we have analysed the effects of a 15 weeks HFD on helplessness assessed in the forced swim test and anhedonia assessed in the sucrose preference test. Two weeks before the start of the behavioural tests, a group of HFD mice were given a combination of two non-absorbable antibiotics, neomycin and polymyxin B. Results: In DIO mice, anhedonia and significant changes in the composition of the gut microbiota at the phyla and family level were observed. On the other hand, there was no significant effect of HFD on the peripheral inflammatory profile. In DIO mice, antibiotic treatment resulted in very pronounced alteration in the composition of the gut microbiota, without any change in anhedonia behaviour. Conclusion: In DIO mice, only four families of bacteria were not affected in their relative abundance by the antibiotic treatment, the Bifidobacteriaceae, Erysipelotrichaceae, Rikenellaceae and Streptococcaceae. This stability concomitant with that of anhedonia suggests that these families may be involved in anhedonia in DIO mice.
ano.nymous@ccsd.cnrs.fr.invalid (Magali Monnoye) 28 Aug 2023
https://hal.inrae.fr/hal-04189068
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[hal-04175302] Recombinant viral hemorrhagic septicemia virus with rearranged genomes as vaccine vectors to protect against lethal betanodavirus infection
The outbreaks of viral hemorrhagic septicemia (VHS) and viral encephalopathy and retinopathy (VER) caused by the enveloped novirhabdovirus VHSV, and the non-enveloped betanodavirus nervous necrosis virus (NNV), respectively, represent two of the main viral infectious threats for aquaculture worldwide. Non-segmented negative-strand RNA viruses such as VHSV are subject to a transcription gradient dictated by the order of the genes in their genomes. With the goal of developing a bivalent vaccine against VHSV and NNV infection, the genome of VHSV has been engineered to modify the gene order and to introduce an expression cassette encoding the major protective antigen domain of NNV capsid protein. The NNV Linker-P specific domain was duplicated and fused to the signal peptide (SP) and the transmembrane domain (TM) derived from novirhabdovirus glycoprotein to obtain expression of antigen at the surface of infected cells and its incorporation into viral particles. By reverse genetics, eight recombinant VHSVs (rVHSV), termed NxGyCz according to the respective positions of the genes encoding the nucleoprotein (N) and glycoprotein (G) as well as the expression cassette (C) along the genome, have been successfully recovered. All rVHSVs have been fully characterized in vitro for NNV epitope expression in fish cells and incorporation into VHSV virions. Safety, immunogenicity and protective efficacy of rVHSVs has been tested in vivo in trout ( Oncorhynchus mykiss) and sole ( Solea senegalensis ). Following bath immersion administration of the various rVHSVs to juvenile trout, some of the rVHSVs were attenuated and protective against a lethal VHSV challenge. Results indicate that rVHSV N2G1C4 is safe and protective against VHSV challenge in trout. In parallel, juvenile sole were injected with rVHSVs and challenged with NNV. The rVHSV N2G1C4 is also safe, immunogenic and efficiently protects sole against a lethal NNV challenge, thus presenting a promising starting point for the development of a bivalent live attenuated vaccine candidate for the protection of these two commercially valuable fish species against two major diseases in aquaculture.
ano.nymous@ccsd.cnrs.fr.invalid (Sandra Souto) 02 Aug 2023
https://hal.inrae.fr/hal-04175302
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[hal-04057783] From In Vitro to In Vivo: A Rational Flowchart for the Selection and Characterization of Candidate Probiotic Strains in Intestinal Disorders
Experimental and clinical evidence has demonstrated the potential of probiotic strains in the prevention or treatment of inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). However, there is little data on what the methodology leading to the identification of such strains should be. In this work, we propose a new flowchart to identify strains with probiotic potential for the management of IBS and IBD, which we tested on a collection of 39 lactic acid bacteria and Bifidobacteria strains. This flowchart included in vitro tests of immunomodulatory properties on intestinal and peripheral blood mononuclear cells (PBMCs), assessment of the barrier-strengthening effect by measuring transepithelial electric resistance (TEER) and quantification of short-chain fatty acids (SCFAs) and aryl hydrocarbon receptor (AhR) agonists produced by the strains. The in vitro results were then combined in a principal component analysis (PCA) to identify strains associated with an anti-inflammatory profile. To validate our flowchart, we tested the two most promising strains identified in the PCA in mouse models of post-infectious IBS or chemically induced colitis to mimic IBD. Our results show that this screening strategy allows the identification of strains with potential beneficial effects on colonic inflammation and colonic hypersensitivity.
ano.nymous@ccsd.cnrs.fr.invalid (Flore Maillard) 06 Dec 2023
https://uca.hal.science/hal-04057783
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[hal-04177128] Staphylococcus epidermidis isolates from atopic or healthy skin have opposite effect on skin cells: potential implication of the AHR pathway modulation
Introduction S taphylococcus epidermidis is a commensal bacterium ubiquitously present on human skin. This species is considered as a key member of the healthy skin microbiota, involved in the defense against pathogens, modulating the immune system, and involved in wound repair. Simultaneously, S. epidermidis is the second cause of nosocomial infections and an overgrowth of S. epidermidis has been described in skin disorders such as atopic dermatitis. Diverse isolates of S. epidermidis co-exist on the skin. Elucidating the genetic and phenotypic specificities of these species in skin health and disease is key to better understand their role in various skin conditions. Additionally, the exact mechanisms by which commensals interact with host cells is partially understood. We hypothesized that S. epidermidis isolates identified from different skin origins could play distinct roles on skin differentiation and that these effects could be mediated by the aryl hydrocarbon receptor (AhR) pathway. Methods For this purpose, a library of 12 strains originated from healthy skin (non-hyperseborrheic (NH) and hyperseborrheic (H) skin types) and disease skin (atopic (AD) skin type) was characterized at the genomic and phenotypic levels. Results and discussion Here we showed that strains from atopic lesional skin alter the epidermis structure of a 3D reconstructed skin model whereas strains from NH healthy skin do not. All strains from NH healthy skin induced AhR/OVOL1 path and produced high quantities of indole metabolites in co-culture with NHEK; especially indole-3-aldehyde (IAld) and indole-3-lactic acid (ILA); while AD strains did not induce AhR/OVOL1 path but its inhibitor STAT6 and produced the lowest levels of indoles as compared to the other strains. As a consequence, strains from AD skin altered the differentiation markers FLG and DSG1. The results presented here, on a library of 12 strains, showed that S. epidermidis originated from NH healthy skin and atopic skin have opposite effects on the epidermal cohesion and structure and that these differences could be linked to their capacity to produce metabolites, which in turn could activate AHR pathway. Our results on a specific library of strains provide new insights into how S. epidermidis may interact with the skin to promote health or disease.
ano.nymous@ccsd.cnrs.fr.invalid (Leslie Landemaine) 04 Aug 2023
https://hal.inrae.fr/hal-04177128
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[anses-04311996] Dissemination of IncI plasmid encoding bla CTX-M-1 is not hampered by its fitness cost in the pig’s gut
ABSTRACT Multiresistance plasmids belonging to the IncI incompatibility group have become one of the most pervasive plasmid types in extended-spectrum beta-lactamase-producing Escherichia coli of animal origin. The extent of the burden imposed on the bacterial cell by these plasmids seems to modulate the emergence of “epidemic” plasmids. However, in vivo data in the natural environment of the strains are scarce. Here, we investigated the cost of a bla CTX-M-1 -IncI1 epidemic plasmid in a commensal E. coli animal strain, UB12-RC, before and after oral inoculation of 15 6- to 8-week- old specific-pathogen-free pigs. Growth rate in rich medium was determined on (i) UB12-RC and derivatives, with or without plasmid, in vivo and/or in vitro evolved, and (ii) strains that acquired the plasmid in the gut during the experiment. Although bla CTX-M-1 -IncI1 plasmid imposed no measurable burden on the recipient strain after conjugation and during the longitudinal carriage in the pig’s gut, we observed a significant difference in the bacterial growth rate between IncI1 plasmid-carrying and plasmid-free isolates collected during in vivo carriage. Only a few mutations on the chromosome of the UB12-RC derivatives were detected by whole-genome sequencing. RNA-Seq analysis of a selected set of these strains showed that transcriptional responses to the bla CTX-M-1 -IncI1 acquisition were limited, affecting metabolism, stress response, and motility functions. Our data suggest that the effect of IncI plasmid on host cells is limited, fitness cost being insufficient to act as a barrier to IncI plasmid spread among natural population of E. coli in the gut niche.
ano.nymous@ccsd.cnrs.fr.invalid (Margaux Allain) 28 Nov 2023
https://anses.hal.science/anses-04311996
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[hal-04116035] Whole‐genome sequencing identifies interferon-induced protein IFI6/IFI27-like as a strong candidate gene for VNN resistance in European sea bass
Background Viral nervous necrosis (VNN) is a major disease that affects European sea bass, and understanding the biological mechanisms that underlie VNN resistance is important for the welfare of farmed fish and sustainability of production systems. The aim of this study was to identify genomic regions and genes that are associated with VNN resistance in sea bass. Results We generated a dataset of 838,451 single nucleotide polymorphisms (SNPs) identified from whole-genome sequencing (WGS) in the parental generation of two commercial populations (A: 2371 individuals and B: 3428 individuals) of European sea bass with phenotypic records for binary survival in a VNN challenge. For each population, three cohorts were submitted to a red-spotted grouper nervous necrosis virus (RGNNV) challenge by immersion and genotyped on a 57K SNP chip. After imputation of WGS SNPs from their parents, quantitative trait loci (QTL) were mapped using a Bayesian sparse linear mixed model (BSLMM). We found several QTL regions that were specific to one of the populations on different linkage groups (LG), and one 127-kb QTL region on LG12 that was shared by both populations and included the genes ZDHHC14, which encodes a palmitoyltransferase, and IFI6/IFI27-like, which encodes an interferon-alpha induced protein. The most significant SNP in this QTL region was only 1.9 kb downstream of the coding sequence of the IFI6/IFI27-like gene. An unrelated population of four large families was used to validate the effect of the QTL. Survival rates of susceptible genotypes were 40.6% and 45.4% in populations A and B, respectively, while that of the resistant genotype was 66.2% in population B and 78% in population A. Conclusions We have identified a genomic region that carries a major QTL for resistance to VNN and includes the ZDHHC14 and IFI6/IFI27-like genes. The potential involvement of the interferon pathway, a well-known anti-viral defense mechanism in several organisms (chicken, human, or fish), in survival to VNN infection is of particular interest. Our results can lead to major improvements for sea bass breeding programs through marker-assisted genomic selection to obtain more resistant fish.
ano.nymous@ccsd.cnrs.fr.invalid (Emilie Delpuech) 02 Jun 2023
https://hal.inrae.fr/hal-04116035
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[hal-04176764] Interplay between a bacterial pathogen and its host in rainbow trout isogenic lines with contrasted susceptibility to Cold Water Disease
Infectious diseases are a major constraint on aquaculture. Genetic lines with different susceptibilities to diseases are useful models to identify resistance mechanisms to pathogens and to improve prophylaxis. Bacterial cold-water disease (BCWD) caused by Flavobacterium psychrophilum represents a major threat for freshwater salmonid farming worldwide. A collection of rainbow trout (Oncorhynchus mykiss) isogenic lines was previously produced from a French domestic population. Here, we compared BCWD resistance phenotypes using a subset of isogenic lines chosen for their contrasted susceptibilities to F. psychrophilum. We applied individual monitoring to document the infection process, including time-course quantification of bacteremia and innate immune response. Strikingly, BCWD resistance was correlated with a lower bacterial growth rate in blood. Several immune genes were expressed at higher levels in resistant fish regardless of infection: the Type II arginase (arg2), a marker for M2 macrophages involved in anti-inflammatory responses and tissue repair, and two Toll-like receptors (tlr2/tlr7), responsible for pathogen detection and inflammatory responses. This study highlights the importance of innate and intrinsic defense mechanisms in determining the outcome of F. psychrophilum infections, and illustrates that non-lethal time-course blood sampling for individual monitoring of bacteremia is a powerful tool to resolve within-host pathogen behavior in bacterial fish diseases.
ano.nymous@ccsd.cnrs.fr.invalid (Bo-Hyung Lee) 03 Aug 2023
https://hal.inrae.fr/hal-04176764
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[anses-04188278] Antimicrobial resistance of Enterococcus cecorum: ECOFF determination
Enterococcus cecorum, a commensal Gram-positive bacterium of the chicken gut, has emerged as a worldwide cause of lameness in poultry, particularly in fast-growing broilers. It is responsible for osteomyelitis, spondylitis and femoral head necrosis, causing animal suffering, mortality and antimicrobial use. Research on the antimicrobial resistance of E. cecorum clinical isolates in France is scarce, and epidemiological cut-off (ECOFF) values unknown. To determine tentative ECOFF (COWT) values for E. cecorum and to investigate the antimicrobial resistance patterns of isolates from mainly French broilers, we tested the susceptibility of a collection of commensal and clinical isolates (n=208) to 29 antimicrobials by the disc diffusion (DD) method. We also determined the minimum inhibitory concentrations (MICs) of 23 antimicrobials by the broth micro-dilution method. To detect chromosomal mutations conferring antimicrobial resistance, we investigated the genomes of 118 E. cecorum isolates mainly obtained from infectious sites and previously described in the literature. We determined the COWT values for more than 20 antimicrobials and identified two chromosomal mutations explaining fluoroquinolone resistance. The DD method appears better suited for detecting E. cecorum antimicrobial resistance. Although tetracycline and erythromycin resistances were persistent in clinical and non-clinical isolates, we found little or no resistance to medically important antimicrobials.
ano.nymous@ccsd.cnrs.fr.invalid (Jeanne Laurentie) 25 Aug 2023
https://anses.hal.science/anses-04188278
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[hal-04083477] Study of the effect of administration of narasin or antibiotics on in vivo selection of a narasin- and multidrug-resistant Enterococcus cecorum strain
Enterococcus cecorum is a member of the normal poultry gut microbiota and an emerging poultry pathogen. Some strains are resistant to key antibiotics and coccidiostats. We evaluated the impact on chicken excretion and persistence of a multidrug-resistant E. cecorum of administering narasin or antibiotics. E. cecorum CIRMBP-1294 (Ec1294) is non-wild-type to many antimicrobials, including narasin, levofloxacin, oxytetracycline and glycopeptides, it has a low susceptibility to amoxicillin, and carries a chromosomal vanA operon. Six groups of 15 chicks each were orally inoculated with Ec1294 and two groups were left untreated. Amoxicillin, oxytetracycline or narasin were administered orally to one group each, either at the recommended dose for five days (amoxicillin, oxytetracycline) or continuously (narasin). Faecal samples were collected weekly and caecal samples were obtained from sacrificed birds on day 28. Ec1294 titres were evaluated by culture on vancomycin- and levofloxacin-supplemented media in 5 % CO2. For inoculated birds given narasin, oxytetracycline or no antimicrobials, vancomycin-resistant enterococci were searched by culture on vancomycin-supplemented media incubated in air, and a PCR was used to detect the vanA gene. Ec1294 persisted in inoculated chicks up to day 28. Compared to the control group, the Ec1294 titre was significantly lower in the amoxicillin- and narasin-receiving groups on days 21 and 28, but was unexpectedly higher in the oxytetracycline-receiving group before and after oxytetracycline administration, preventing a conclusion for this group. No transfer of the vanA gene to other enterococci was detected. Other trials in various experimental conditions should now be conducted to confirm this apparent absence of co-selection of the multi-drug-resistant E. cecorum by narasin or amoxicillin administration.
ano.nymous@ccsd.cnrs.fr.invalid (Jeanne Laurentie) 27 Apr 2023
https://hal.inrae.fr/hal-04083477
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[hal-04175372] Differential Salmonella Typhimurium intracellular replication and host cell responses in caecal and ileal organoids derived from chicken
Chicken infection with Salmonella Typhimurium is an important source of foodborne human diseases. Salmonella colonizes the avian intestinal tract and more particularly the caecum, without causing symptoms. This thus poses a challenge for the prevention of foodborne transmission. Until now, studies on the interaction of Salmonella with the avian gut intestine have been limited by the absence of in vitro intestinal culture models. Here, we established intestinal crypt‐derived chicken organoids to better decipher the impact of Salmonella intracellular replication on avian intestinal epithelium. Using a 3D organoid model, we observed a significantly higher replication rate of the intracellular bacteria in caecal organoids than in ileal organoids. Our model thus recreates intracellular environment, allowing Salmonella replication of avian epithelium according to the intestinal segment. Moreover, an inhibition of the cellular proliferation was observed in infected ileal and caecal organoids compared to uninfected organoids. This appears with a higher effect in ileal organoids, as well as a higher cytokine and signaling molecule response in infected ileal organoids at 3 h post-infection (hpi) than in caecal organoids that could explain the lower replication rate of Salmonella observed later at 24 hpi. To conclude, this study demonstrates that the 3D organoid is a model allowing to decipher the intracellular impact of Salmonella on the intestinal epithelium cell response and illustrates the importance of the gut segment used to purify stem cells and derive organoids to specifically study epithelial cell - Salmonella interaction.
ano.nymous@ccsd.cnrs.fr.invalid (Sonia Lacroix-Lamandé) 02 Aug 2023
https://hal.inrae.fr/hal-04175372
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[hal-04205854] In ovo administration of a phage cocktail partially prevents colibacillosis in chicks
Avian pathogenic Escherichia coli (APEC) causes colibacillosis, the main bacterial disease in poultry leading to significant economic losses worldwide. Antibiotic treatments favor the emergence of multidrug-resistant bacteria, and preventive measures are insufficient to control the disease. There is increasing interest in using the potential of bacteriophages, not only for phage therapy but also for prevention and biocontrol. This study aimed to evaluate the efficacy of a phage cocktail administered in ovo to prevent avian colibacillosis in chicks. When 4 different phages (REC, ESCO3, ESCO47, and ESCO58), stable under avian physiological conditions, were combined and inoculated at 17 embryogenic days (ED), they were transmitted to the newly hatched chicks. In a second trial, the 4-phage cocktail was inoculated into the allantoic fluid at ED16 and after hatch 1-day-old chicks were challenged with the O2 APEC strain BEN4358 inoculated subcutaneously. Two phages (REC and ESCO3) were still detected in the ceca of surviving chicks at the end of the experiment (7-days postinfection). Chicks that received the phages in ovo did not develop colibacillosis lesions and showed a significant decrease in intestinal BEN4358 load (8.00 × 107 CFU/g) compared to the challenged chicks (4.52 × 108 CFU/g). The majority of the reisolated bacteria from the ceca of surviving chicks had developed full resistance to ESCO3 phage, and only 3 were resistant to REC phage. The partially or complete resistance of REC phage induced a considerable cost to bacterial virulence. Here, we showed that phages inoculated in ovo can partially prevent colibacillosis in 1-wk-old chicks. The reduction in the APEC load in the gut and the decreased virulence of some resistant isolates could also contribute to control the disease.
ano.nymous@ccsd.cnrs.fr.invalid (Marianne Nicolas) 13 Sep 2023
https://hal.inrae.fr/hal-04205854
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[anses-04261882] Investigations into SARS-CoV-2 and other coronaviruses on mink farms in France late in the first year of the COVID-19 pandemic
Soon after the beginning of the COVID-19 pandemic in early 2020, the Betacoronavirus SARS-CoV-2 infection of several mink farms breeding American minks ( Neovison vison ) for fur was detected in various European countries. The risk of a new reservoir being formed and of a reverse zoonosis from minks quickly became a major concern. The aim of this study was to investigate the four French mink farms to see whether SARS-CoV-2 was circulating there in late 2020. The investigations took place during the slaughtering period, thus facilitating different types of sampling (swabs and blood). On one of the four mink farms, 96.6% of serum samples were positive when tested with a SARS-CoV-2 ELISA coated with purified N protein recombinant antigen, and 54 out of 162 (33%) pharyngo-tracheal swabs were positive by RT-qPCR. The genetic variability among 12 SARS-CoV-2 genomes sequenced from this farm indicated the co-circulation of several lineages at the time of sampling. All the SARS-CoV-2 genomes detected were nested within the 20A clade (Nextclade), together with SARS-CoV-2 genomes from humans sampled during the same period. The percentage of SARS-CoV-2 seropositivity by ELISA varied between 0.3 and 1.1% on the other three farms. Interestingly, among these three farms, 11 pharyngo-tracheal swabs and 3 fecal pools from two farms were positive by end-point RT-PCR for an Alphacoronavirus very similar to a mink coronavirus sequence observed on Danish farms in 2015. In addition, a mink Caliciviridae was identified on one of the two farms positive for Alphacoronavirus . The clinical impact of these inapparent viral infections is not known. The co-infection of SARS-CoV-2 with other viruses on mink farms could help explain the diversity of clinical symptoms noted on different infected farms in Europe. In addition, the co-circulation of an Alphacoronavirus and SARS-CoV-2 on a mink farm would potentially increase the risk of viral recombination between alpha and betacoronaviruses as already suggested in wild and domestic animals, as well as in humans.
ano.nymous@ccsd.cnrs.fr.invalid (Marine Wasniewski) 27 Oct 2023
https://anses.hal.science/anses-04261882
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[hal-04129892] The Brown Alga Bifurcaria bifurcata Presents an Anthelmintic Activity on All Developmental Stages of the Parasitic Nematode Heligmosomoides polygyrus bakeri
The current control of gastrointestinal (GI) parasitic nematodes mainly relies on the widespread use of anthelmintics, which has inevitably led to resistance. Therefore, there is an urgent need to find new sources of antiparasitic compounds. Macroalgae represent a rich source of active molecules and are widely described as having medicinal properties. In the present study, we investigated the potential anthelmintic activity of aqueous extracts from three species of algae (Bifurcaria bifurcata, Grateloupia turuturu and Osmundea pinnatifida) on the murine parasite Heligmosomoides polygyrus bakeri. Using a set of complementary in vitro tests, including larval development assays, egg hatching tests and nematicidal activity assays on larvae and adults, we report the nematicidal activity of aqueous extracts of B. bifurcata. In addition, aqueous extract fractionation using liquid/liquid partitioning with a solvent of increasing polarity was performed in order to identify the groups of active molecules underlying the anthelmintic activity. Non-polar extracts (heptane, ethyl acetate) demonstrated high anthelmintic potential, highlighting the role of non-polar metabolites such as terpenes. Here, we highlight the strong anthelmintic potential of the brown alga B. bifurcata on a mouse model of GI parasites, thus confirming the strong interest in algae as natural alternatives for the control of parasitic nematodes.
ano.nymous@ccsd.cnrs.fr.invalid (Morgane Miclon) 15 Jun 2023
https://hal.inrae.fr/hal-04129892
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[hal-04187670] The caecal microbiota promotes the acute inflammatory response and the loss of the intestinal barrier integrity during severe Eimeria tenella infection
Introduction Coccidiosis, a disease caused by intestinal apicomplexan parasites Eimeria , is a threat to poultry production. Eimeria tenella is one of the most pathogenic species, frequently causing a high prevalence of opportunistic infections. Objective The objective of this study is to investigate the role of the microbiota in the pathogenesis of severe Eimeria tenella infection. Methods We have previously shown that microbiota can promote parasite development. To study the effect of the microbiota on the pathogenesis of this infection, we used an experimental condition (inoculum of 10 000 oocysts E. tenella INRAE ) in which the parasite load is similar between germ-free and conventional broilers at 7 days post-infection (pi). Thirteen conventional and 24 germ-free chickens were infected. Among this latter group, 12 remained germ-free and 12 received a microbiota from conventional healthy chickens at 4 days pi. Caeca and spleens were collected at 7 days pi. Results Our results demonstrated caecal lesions and epithelium damage in conventional chickens at 7 days pi but not in germ-free infected chickens. Administration of conventional microbiota to germ-free chickens partially restored these deleterious effects. At day 7 pi, both infected conventional and germ-free chickens exhibited increased gene expression of inflammatory mediators, including IL15, IFNγ, TNFα and the anti-inflammatory mediator SOCS1 , whereas the inflammatory mediators CXCLi2, CCL20, IL18, CSF1, NOS2, PTGS2, IL1β, IL6 , the receptor CCR2 , and the anti-inflammatory mediators TGFβ1 and IL10 were upregulated only in infected conventional chickens. Notably, the IL18, PTGS2 gene expression was significantly higher in the infected conventional group. Overall, the inflammatory response enhanced by the microbiota might be in part responsible for higher lesion scores. Epithelial tight junction protein gene expression analysis revealed a significant upregulation of CLDN1 with the infection and microbiota, indicating a potential loss of the intestinal barrier integrity. Conclusion These observations imply that, during E. tenella infection, the caecal microbiota could trigger an acute inflammatory response, resulting in a loss of intestinal integrity. Increase in bacterial translocation can then lead to the likelihood of opportunistic infections. Hence, modulating the microbiota may offer a promising strategy for improving poultry gut health and limiting caecal coccidiosis.
ano.nymous@ccsd.cnrs.fr.invalid (Florian Tomal) 25 Aug 2023
https://hal.inrae.fr/hal-04187670
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[hal-04271263] Non-Steroidal Estrogens Inhibit Influenza Virus by Interacting with Hemagglutinin and Preventing Viral Fusion
Influenza virus is one of the main causes of respiratory infections worldwide. Despite the availability of seasonal vaccines and antivirals, influenza virus infections cause an important health and economic burden. Therefore, the need to identify alternative antiviral strategies persists. In this study, we identified non-steroidal estrogens as potent inhibitors of influenza virus due to their interaction with the hemagglutinin protein, preventing viral entry. This activity is maintained in vitro, ex vivo, and in vivo. Therefore, we found a new domain to target on the hemagglutinin and a class of compounds that could be further optimized for influenza treatment.
ano.nymous@ccsd.cnrs.fr.invalid (Elisa Franzi) 10 Nov 2023
https://hal.science/hal-04271263
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[hal-04171667] Établissement d'un modèle d'anse intestinale chez l'agneau nouveau-né afin d'évaluer de nouvelles méthodes de lutte contre les maladies entériques et de réduire l'utilisation d'animaux de laboratoire
Dans le but d'évaluer des alternatives naturelles pour contrôler la cryptosporidiose, infection entérique parasitaire affectant principalement les jeunes ruminants d'espèce de rente mais également l'être humain (zoonose), nous utilisons les agneaux comme espèce cible et comme modèle pour les animaux de plus grande taille comme les veaux. Nous avons pour objectif de stimuler les réponses immunitaires des animaux dès la naissance avec du colostrum supplémenté avec des produits naturels tels que des produits dérivés de levures qui contiennent des ligands des récepteurs de l'immunité innée. Cependant, la tolérance immunitaire intestinale s'installe rapidement après la naissance en réponse à la colonisation microbienne débutant dès la mise-bas par voie naturelle et par la suite via le colostrum, le lait et les multiples contacts avec l'environnement, et se caractérise par une hypo-réactivité aux antigènes microbiens (cf. modèles murins). Nous avons donc développé le modèle de chirurgie des anses intestinales sur agneaux nouveau-nés mis au monde par césarienne (et donc sans flore commensale) adapté à l'étude des interactions hôte-agent pathogène dans un environnement contrôlé et à l'évaluation de nouveaux composés antiparasitaires naturels in vivo. La possibilité de comparer différents produits naturels simultanément ainsi que des effets doses sur ce modèle, permet de réduire considérablement le nombre d’animaux expérimentaux à utiliser. Pour faciliter la réalisation de ces protocoles expérimentaux, nous utilisons notre troupeau d'ovins qui synchronise les mises-bas. Le jour de la chirurgie, la brebis est transférée dans la salle de chirurgie (confinement de niveau 2). Une césarienne est pratiquée et les agneaux sont réanimés. Après une courte phase de récupération, un agneau est choisi et transféré en salle de chirurgie. Il est installé sur une table de réanimation néonatale. Le protocole d'anesthésie / analgésie comprend : induction au masque (isoflurane), pose d'une sonde endotrachéale sous anesthésie locale (xylocaïne), maintien sous isoflurane (ventilation contrôlée), analgésie parentérale (buprénorphine), pose d'un cathéter veineux et mise sous perfusion, anesthésie locale traçante (lidocaïne). Pendant toute la procédure, les paramètres suivants sont surveillés : fréquences cardiaque et respiratoire, température rectale, SaO2, ETCO2. Une chirurgie à 4 mains est ensuite réalisée : - Extériorisation de la jonction iléo-caecale (IC) et de la portion distale de l'intestin grêle (IG)) ; - Ligatures avec création en général de triplicats - séparés par un inter-segment vide de "sécurité", y compris en amont et en aval de l'anse - (9 triplicats pour une anse de 50 cm environ) ; - Entérotomie en aval de l'anse ainsi créée, à proximité de la jonction IC, suture de l'intestin du côté de l'anse, puis idem en amont ; - Anastomose termino-terminale ; - Injection des préparations d'intérêt dans chaque segment. Pendant la chirurgie, une irrigation régulière de la portion externalisée de l'intestin est réalisée au sérum physiologique tiédi.
ano.nymous@ccsd.cnrs.fr.invalid (Nathalie Kasal-Hoc) 26 Jul 2023
https://hal.inrae.fr/hal-04171667
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[hal-04172440] Conserved and divergent arms of the antiviral response in the duplicated genomes of salmonid fishes
Antiviral innate immunity is orchestrated by the interferon system, which appeared in ancestors of jawed vertebrates. Interferon upregulation induces hundreds of interferon-stimulated-genes (ISGs) with effector or regulatory functions. Here we investigated the evolutionary diversification of ISG responses through comparison of two salmonid fishes, accounting for the impact of sequential whole genome duplications ancestral to teleosts and salmonids. We analysed the transcriptomic response of the IFN pathway in the head kidney of rainbow trout and Atlantic salmon, which separated 25-30 Mya. We identified a large set of ISGs conserved in both species and cross-referenced them with zebrafish and human ISGs. In contrast, around one-third of salmonid ISG lacked orthologs in human, mouse, chicken or frog, and often between rainbow trout and Atlantic salmon, revealing a fast-evolving, lineage-specific arm of the antiviral response. This study also provides a key resource for in-depth functional analysis of ISGs in salmonids of commercial significance.
ano.nymous@ccsd.cnrs.fr.invalid (Thomas C Clark) 27 Jul 2023
https://hal.inrae.fr/hal-04172440
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[hal-04127637] DNA methylation and gene expression changes in mouse mammary tissue during successive lactations: part I – the impact of inflammation
Mastitis is among the main reasons women cease breastfeeding, which leads to them supplementing breast milk with artificial formula. In farm animals, mastitis results in significant economic losses and the premature culling of some animals. Nevertheless, researchers do not know enough about the effect of inflammation on the mammary gland. This article discusses the changes to DNA methylation in mouse mammary tissue caused by lipopolysaccharide-induced inflammation (4 h post-injection of lipopolysaccharide). We analysed the expression of some genes related to mammary gland function, epigenetic regulation, and the immune response. The analysis focused on three comparisons: inflammation during the first lactation, inflammation during second lactation with no history of inflammation, and inflammation during second lactation with previous inflammation. We identified differentially methylated cytosines (DMCs), differentially methylated regions (DMRs), and some differentially expressed genes (DEGs) for each comparison. The three comparisons shared some DEGs; however, few DMCs and only one DMR were shared. These observations suggest that inflammation is one of several factors affecting epigenetic regulation during successive lactations. Furthermore, the comparison between animals in second lactation with and without inflammation, with no inflammation history during first lactation showed a different pattern compared to the other conditions in this experiment. This indicates that inflammation history plays an important role in determining epigenetic changes. The data presented in this study suggest that lactation rank and previous inflammation history are equally important when explaining mammary tissue gene expression and DNA methylation changes.
ano.nymous@ccsd.cnrs.fr.invalid (E. Ivanova) 14 Jun 2023
https://hal.inrae.fr/hal-04127637
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[hal-04332121] A pig model of chronic hepatitis E displaying persistent viremia and a downregulation of innate immune responses in the liver
Background: Hepatitis E virus (HEV) is a zoonotic virus transmitted by pig meat and responsible for chronic hepatitis E in immunocompromised patients. It has proved challenging to reproduce this disease in its natural reservoir. We therefore aimed to develop a pig model of chronic hepatitis E to improve the characterization of this disease. Methods: Ten pigs were treated with a tacrolimus-based regimen and intravenously inoculated with HEV. Tacrolimus trough concentration, HEV viremia, viral diversity, innate immune responses, liver histology, clinical disease and biochemical markers were monitored for 11 weeks post-infection (p.i.). Results: HEV viremia persisted for 11 weeks p.i. HEV RNA was detected in the liver, small intestine, and colon at necropsy. Histological analysis revealed liver inflammation and fibrosis. Several mutations selected in the HEV genome were associated with compartmentalization in the feces and intestinal tissues, consistent with the hypothesis of extrahepatic replication in the digestive tract. Antiviral responses were characterized by a downregulation of IFN pathways in the liver, despite an upregulation of RIG-I and ISGs in the blood and liver. Conclusions: We developed a pig model of chronic hepatitis E that reproduced the major hallmarks of this disease. This model revealed a compartmentalization of HEV genomes in the digestive tract and a downregulation of innate immune responses in the liver. These original features highlight the relevance of our model for studies of the pathogenesis of chronic hepatitis E and for validating future treatments.
ano.nymous@ccsd.cnrs.fr.invalid (Nancy León-Janampa) 08 Dec 2023
https://hal.science/hal-04332121
