75 research outputs found

    Radial velocities, dynamics of stars and nebulosities with GAIA and VLT-GIRAFFE

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    Proceedings GSD2008 conference, submitted to ANThis document is divided in two parts. The first part deals with the radial velocities (RV) distributions for B-type stars and nebulosities observed with the VLT-GIRAFFE in the Large and Small Magellanic Clouds towards the open clusters NGC2004 and NGC330. Thanks to the resolution of GIRAFFE spectra, we found that the RV distribution for the nebulosities in the LMC is bi-modal. This bi-modality can be interpreted, in term of dynamics, by the expansion of the LMC4 superbubble. The second part deals with the GAIA space mission and the determination of the radial velocities by using Radial Velocity Spectrometer (RVS) spectra. The methods to determine the radial velocities are presented as well as preliminary results on simulated RVS spectra

    Endosymbiotic Sinorhizobium meliloti modulate Medicago root susceptibility to secondary infection via ethylene

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    A complex network of pathways coordinates nodulation and epidermal root hair infection in the symbiotic interaction between rhizobia and legume plants. Whereas nodule formation was known to be autoregulated, it was so far unclear whether a similar control is exerted on the infection process. We assessed the capacity of Medicago plants nodulated by Sinorhizobium meliloti to modulate root susceptibility to secondary bacterial infection or to purified Nod factors in split-root and volatile assays using bacterial and plant mutant combinations. Ethylene implication in this process emerged from gas production measurements, use of a chemical inhibitor of ethylene biosynthesis and of a Medicago mutant affected in ethylene signal transduction. We identified a feedback mechanism that we named AOI (for Autoregulation Of Infection) by which endosymbiotic bacteria control secondary infection thread formation by their rhizospheric peers. AOI involves activation of a cyclic adenosine 30,50-monophosphate (cAMP) cascade in endosymbiotic bacteria, which decreases both root infectiveness and root susceptibility to bacterial Nod factors. These latter two effects are mediated by ethylene. AOI is a novel component of the complex regulatory network controlling the interaction between Sinorhizobium meliloti and its host plants that emphasizes the implication of endosymbiotic bacteria in fine-tuning the interaction

    Prevalence of Yersinia Species in the Ileum of Crohn's Disease Patients and Controls

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    Yersinia are common contaminants of food products, but their prevalence in the human gut is poorly documented. Yersinia have been implicated in Crohn's Disease (CD, an inflammatory bowel disease) however their role in CD is controversial. We performed highly sensitive PCR assays of specific sequences for the gyrB gene of Y. aldovae, Y. bercovieri, Y. enterocolitica, Y. intermedia, Y. mollaretii and the inv gene of Y. pseudotuberculosis. We analyzed a total of 470 ileal samples taken from 338 participants (262 CD patients and 76 controls) belonging to three independent cohorts. All patients and controls were phenotyped and genotyped for the main CD susceptibility variants: NOD2, ATG16L1, and IRGM. Yersinia were found in 7.7% of ileal samples (respectively 7.9 and 7.6% in controls and CD patients) corresponding to 10% of participants (respectively 11.8 and 9.5% in controls and CD patients). Y. enterocolitica, Y. pseudotuberculosis and Y. intermedia were the most frequently identified species. The bacteria were more frequent in resected specimens, lymph nodes and Peyer's patches. Yersinia were no more likely to be detected in CD tissues than tissues from inflammatory and non-inflammatory controls. CD patients treated with immunosuppressants were less likely to be Yersinia carriers. In conclusion, this work shows that Yersinia species are frequently found at low levels in the human ileum in health and disease. The role of Yersinia species in this ecosystem should now be explored

    Functional abdominal pain disorders and patient- and parent- reported outcomes in children with inflammatory bowel disease in remission

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    BACKGROUND: Chronic abdominal pain occurs frequently in pediatric patients with inflammatory bowel disease (IBD) in remission. AIMS: To assess the prevalence and factors associated with Functional Abdominal Pain Disorders among IBD children in remission (IBD-FAPD). METHODS: Patients with IBD for > 1 year, in clinical remission for ≥ 3 months were recruited from a National IBD network. IBD-FAPDs were assessed using the Rome III questionnaire criteria. Patient- or parent- reported outcomes were assessed. RESULTS: Among 102 included patients, 57 (56%) were boys, mean age (DS) was 15.0 (± 2.0) years and 75 (74%) had Crohn's disease. Twenty-two patients (22%) had at least one Functional Gastrointestinal Disorder among which 17 had at least one IBD-FAPD. Past severity of disease or treatments received and level of remission were not significantly associated with IBD-FAPD. Patients with IBD-FAPD reported more fatigue (peds-FACIT-F: 35.9 ± 9.8 vs. 43.0 ± 6.9, p = 0.01) and a lower HR-QoL (IMPACT III: 76.5 ± 9.6 vs. 81.6 ± 9.2, p = 0.04) than patients without FAPD, and their parents had higher levels of State and Trait anxiety than the other parents. CONCLUSIONS: Prevalence of IBD-FAPD was 17%. IBD-FAPD was not associated with past severity of disease, but with fatigue and lower HR-QoL

    A first update on mapping the human genetic architecture of COVID-19

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    Ovide antique : quel classique ?

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    Delibes-Videau Anne, Viala Alain. Ovide antique : quel classique ?. In: Littératures classiques, n°19, automne 1993. Qu’est-ce qu’un classique ? pp. 35-59
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