Émergence, dynamique évolutive et écologie de lignées pathogènes de bivalves marins au sein de l’espèce bactérienne Vibrio aestuarianus

The oyster Crassostrea gigas is the most cultured species of bivalve in the world and is confronted with infectious diseases involving bacteria of the genus Vibrio. Among these Vibrio, the species V. aestuarianus, initially described in 1983 as a bacterium of estuarine environments, has been associated with mortality of adult oysters in Europe since 2001. In 2012, mortality of adult cockles Cerastoderma edule associated with this species have also been reported. However, the processes leading to the emergence of pathogenic bivalve lineages have remained unknown. During this thesis, we sought to clarify (1) the population structure of V. aestuarianus and their genomic determinants, (2) the evolutionary events that participated in the emergence and evolution of the subspecies, and (3) the habitats, cycles and species sensitive toV. aestuarianus. We have shown that pathogenic V. aestuarianus strains fall into two subspecies withdifferent evolutionary histories. V. aestuarianus francensis, described in 2008, includes pathogenic oyster strains while V. aestuarianus cardii includes pathogenic cockle strains. Both subspecies cause disease in their host populations in summer, and temperature has been identified as a favorable factor for disease development. V. aestuarianus francensis impacts oyster farming and we show that two distinct lineages have spread across Europe for at least 20 years. This subspecies is characterized by low genetic diversity and essentially clonal evolution. Strains of V. aestuarianus francensis have a specialist lifestyle, with a habitat restricted to oysters. One of the events that favored its emergence could be the acquisition and genomic integration of a mobile genetic element containing genes coding for proteins involved in copper export. Currently, the subspecies V. aestuarianus cardii impacts cockles only in France. The phenotypic and genetic diversity in this subspecies is greater than in the subspecies V. aestuarianus francensis. Several genetic groups with different levels of virulence towards cockles could be identified and the comparison of genomes between these groups made it possible to identify potential virulence factors.L’huître creuse Crassostrea gigas est l’espèce de bivalve la plus cultivée dans le monde et est confrontée à des maladies infectieuses impliquant des bactéries du genre Vibrio. Parmi ces Vibrio, l’espèce V.aestuarianus, initialement décrite en 1983 comme bactérie des environnements estuariens, est associée à des mortalités d’huîtres creuses adultes en Europe depuis 2001. En 2012, des mortalités de coques adultes Cerastoderma edule associées à cette espèce ont également été rapportées. Cependant, les processus ayant mené à l’émergence des lignées pathogènes de bivalves sont restés inconnus. Au cours de cette thèse, nous avons cherché à préciser (1) la structure des populations de V. aestuarianus et leurs déterminants génomiques ; (2) les évènements évolutifs ayant participé à l’émergence et l’évolution dessous-espèces, et (3) les habitats, cycles et espèces sensibles à V. aestuarianus. Nous avons montré que les souches de V. aestuarianus pathogènes se répartissent dans deux sous-espèces aux histoires évolutives différentes. V. aestuarianus francensis, décrite en 2008, regroupe les souches pathogènes d’huîtres alors que V. aestuarianus cardii regroupe les souches pathogènes de coques. Les deux sous espèces provoquent des maladies dans leurs populations d’hôtes en été, et la température a été identifiée comme un facteur favorable au développement des maladies. V. aestuarianus francensis impacte l’ostréiculture et nous montrons que deux lignées distinctes se sont propagées à l’échelle de l’Europe depuis au moins 20 ans. Cette sous-espèce se caractérise par une faible diversité génétique et une évolution essentiellement clonale. Les souches de V. aestuarianus francensis ont un mode de vie de spécialiste, avec un habitat restreint aux huîtres. L’un des évènements ayant favorisé son émergence pourrait être l’acquisition et l’intégration génomique d’un élément génétique mobile contenant des gènes codant des protéines impliquées dans l’export du cuivre. Actuellement, la sous-espèce V. aestuarianuscardii impacte les coques uniquement en France. La diversité phénotypique et génétique dans cette sous espèce est plus importante que dans la sous-espèce V. aestuarianus francensis. Plusieurs groupes génétiques présentant des niveaux de virulence différents envers les coques ont pu être identifiées et la comparaison des génomes entre ces groupes a permis d’identifier des facteurs de virulence potentiels

Emergence and clonal expansion of Vibrio aestuarianus lineages pathogenic for oystersin Europe

International audienceCrassostrea gigas oysters represent a significant global food source, with 4.7 million tons harvested per year. In 2001, the bacterium Vibrio aestuarianus francensis emerged as a pathogen that causes adult oyster mortality in France and Ireland. Its impact on oyster aquaculture has increased in Europe since its reemergence in 2012. To better understand the evolutionary mechanisms leading to the emergence and persistence over time of this pathogen, we conducted a survey of mollusk diseases through national reference laboratories (NRLs) across Europe. We analyzed54 new genomes of Vibrio Aestuarianus (Va) isolated from multiple environmental compartments since 2001, in areas with and withoutbivalve mortalities. We used a combination of comparative genomics and population genetics approaches and show thatVa has a classical epidemic population structure from which the pathogenic Va francensis subspecies emerged and clonally expanded. Furthermore, we identified a specific cus-cop-containing island conferring copper resistance to Va francensis whose acquisition may have favored the emergence of pathogenic lineages adapted and specialized to oysters

Emergence and clonal expansion of Vibrio aestuarianus lineages pathogenic for oysters in Europe

Crassostrea gigas oysters represent a significant global food source with 4.7 million tons harvested per year. In 2001, the bacterium Vibrio aestuarianus subsp. francensis emerged as a pathogen that causes adult oyster mortality in France and Ireland. Its impact on oyster aquaculture has increased in Europe since its re-emergence in 2012. To better understand the evolutionary mechanisms leading to the emergence and persistence over time of this pathogen, we conducted a survey of mollusc diseases through national reference laboratories across Europe. We analysed 54 new genomes of Vibrio aestuarianus (Va) isolated from multiple environmental compartments since 2001, in areas with and without bivalve mortalities. We used a combination of comparative genomics and population genetics approaches and show that Va has a classical epidemic population structure from which the pathogenic Va francensis subspecies emerged and clonally expanded. Furthermore, we identified a specific cus-cop-containing island conferring copper resistance to Va francensis whose acquisition may have favoured the emergence of pathogenic lineages adapted and specialized to oysters.info:eu-repo/semantics/acceptedVersio

Pseudoxanthoma Elasticum overlaps Hereditary Spastic Paraplegia Type 56

International audienc

Nation et nations au Moyen Âge

Il peut sembler paradoxal, au moment où l'histoire globale semble conquérir chaque jour un terrain plus vaste, quelle qu'en soit la période, de réfléchir encore à la « nation ». Toutefois, en réponse à une mondialisation vécue comme la dissolution d'entités et d'identités historiques spécifiques et durables, la nation semble ici et là accomplir un retour qui ne pouvait laisser les médiévistes indifférents, tant il est vrai que c'est souvent au Moyen Âge, prétend-on, que les nations modernes se seraient formées. Cependant, le mot « nation » a été à ce point investi de sens nouveaux depuis au moins le xviiie siècle que parler des nations au Moyen Âge suppose un aller-retour permanent entre Moyen Âge et modernité, exige de prêter attention à la manière dont des processus territoriaux, politiques, étatiques et aristocratiques qui appartiennent en propre à l'ethnogenèse médiévale ont été rétroactivement « nationalisés » au sens moral, affectif, guerrier et idéologique du terme

Discordance du temps

La centralité de l'urgence et les bouleversements des rythmes sociaux produisent de nouveaux régimes temporels, qui remettent en cause les liens et les pratiques communicationnels, les pratiques de transmission et de médiation. Ces mutations, dont les multiples conséquences restent à évaluer, ont déjà retenu l'attention d'anthropologues, d'historiens, d'économistes, de politologues ou de philosophes. Le présent ouvrage propose une approche communicationnelle des enjeux et des problèmes suscités par ces mutations temporelles. Le laboratoire MICA (Médiation, Information, Communication, Arts), équipe d'accueil de la formation doctorale en Sciences de l'information de la Communication et en Arts de l'Université Michel de Montaigne - Bordeaux 3, a déjà tenu plusieurs colloques et réalisé des travaux sur les temporalités médiatiques et l'urgence communicationnelle. Il s'agit ici, à partir des bénéfices de ces premières investigations et des éclairages apportés par les recherches les plus récentes, de prolonger cette réflexion

Effect of general anaesthesia on functional outcome in patients with anterior circulation ischaemic stroke having endovascular thrombectomy versus standard care: a meta-analysis of individual patient data

Background: General anaesthesia (GA) during endovascular thrombectomy has been associated with worse patient outcomes in observational studies compared with patients treated without GA. We assessed functional outcome in ischaemic stroke patients with large vessel anterior circulation occlusion undergoing endovascular thrombectomy under GA, versus thrombectomy not under GA (with or without sedation) versus standard care (ie, no thrombectomy), stratified by the use of GA versus standard care. Methods: For this meta-analysis, patient-level data were pooled from all patients included in randomised trials in PuMed published between Jan 1, 2010, and May 31, 2017, that compared endovascular thrombectomy predominantly done with stent retrievers with standard care in anterior circulation ischaemic stroke patients (HERMES Collaboration). The primary outcome was functional outcome assessed by ordinal analysis of the modified Rankin scale (mRS) at 90 days in the GA and non-GA subgroups of patients treated with endovascular therapy versus those patients treated with standard care, adjusted for baseline prognostic variables. To account for between-trial variance we used mixed-effects modelling with a random effect for trials incorporated in all models. Bias was assessed using the Cochrane method. The meta-analysis was prospectively designed, but not registered. Findings: Seven trials were identified by our search; of 1764 patients included in these trials, 871 were allocated to endovascular thrombectomy and 893 were assigned standard care. After exclusion of 74 patients (72 did not undergo the procedure and two had missing data on anaesthetic strategy), 236 (30%) of 797 patients who had endovascular procedures were treated under GA. At baseline, patients receiving GA were younger and had a shorter delay between stroke onset and randomisation but they had similar pre-treatment clinical severity compared with patients who did not have GA. Endovascular thrombectomy improved functional outcome at 3 months both in patients who had GA (adjusted common odds ratio (cOR) 1·52, 95% CI 1·09–2·11, p=0·014) and in those who did not have GA (adjusted cOR 2·33, 95% CI 1·75–3·10, p<0·0001) versus standard care. However, outcomes were significantly better for patients who did not receive GA versus those who received GA (covariate-adjusted cOR 1·53, 95% CI 1·14–2·04, p=0·0044). The risk of bias and variability between studies was assessed to be low. Interpretation: Worse outcomes after endovascular thrombectomy were associated with GA, after adjustment for baseline prognostic variables. These data support avoidance of GA whenever possible. The procedure did, however, remain effective versus standard care in patients treated under GA, indicating that treatment should not be withheld in those who require anaesthesia for medical reasons