Novembre 2023
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Mardi 07/11/2023 Amphi Pasteur Séminaire Externe |
« Unravelling the secrets of bacterial Type 4 Secretion Systems : from pilus biogenesis to pathogenicity » | |
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Dr. Kévin MACE (Group Leader Université de Rennes-CNRS - Institute Genetics & Development of Rennes) Host : Patricia Doublet
Bacterial Type 4 Secretion Systems (T4SS) represent remarkable nanomachines that mediate the transfer of various substrates from a donor to a recipient cell. T4SS have two pivotal functions: 1) firstly, they facilitate the exchange of genetic material among prokaryotes, a process referred to as "conjugation". Conjugation is the major driver of genome dynamics and evolution, including playing a critical role in the rapid dissemination of antibiotic resistance. 2) Secondly, certain pathogenic bacteria exploit T4SS to deliver virulence proteins into both prokaryotic and eukaryotic cells, thereby instigating severe diseases including chronic infections and cancers.
In this talk, I will present the first high-resolution structure of a colossal 2.8 MegaDalton T4SS complex involved in pilus biogenesis, solved using cryo-EM and validated by state-of-art co-evolution analysis (AlphaFOLD2). Secondly, I will present the cryo-EM structure of the substrate recruiting platform employed by the pathogenic bacterium Legionella pneumophila. This structure not only showcases the high-resolution architecture of the platform but also unveils a two effectors recruitment mechanistic models. |
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Vendredi 10/11/2023 Seminar room IBCP Séminaire Externe |
« UVB-induced senescence as a simplified model of skin photoaging » | |
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Dr. Florence CHAINIAUX (Université de Namur, Belgique)
Hôte :Pr. Jérôme Lamartine
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Jeudi 16/11/2023 Amphi G3 - ISFA Séminaire Externe |
" Antibiotic-induced morphological changes in bacteria boost phage predation » | |
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Dr. Mireille ANSALDI (Laboratoire de Chimie bactérienne de Marseille)
Hôte : Elisabeth Kay
Séminaire invité dans le cadre de la journée du G-RREM (Groupe Régional de Recherche en Microbiologie des Interactions) The presence of antibiotics at sublethal concentrations affects bacterial physiology, sometimes allowing phages to propagate more rapidly and leading to increased bacterial eradication. In addition, phage addition also reduces antibiotic-driven mutagenesis, which is an essential parameter to consider for therapeutic uses of phages. Our aim is to study these tripartite antibiotic-host-phage interactions using single cell/phage and whole population imaging techniques. We also aim to predict the outcome of such complex interactions on bacterial cell viability and viral propagation.
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Mardi 21/11/2023 Day Université Lumière Lyon 2 Journée Scientifique
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EvoLyon 2023 | |
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Le comité d'organisation d'EvoLyon (Guillaume Beslon, Christophe Douady, Laurent Duret, Gilles Escarguel, Lucie Etienne, Abderrahman Khila, Marie Monniaux, Sophie Pantalacci et François Pellegrino)
Le meeting EvoLyon 2023 aura lieu le 21 novembre à l'Université Lumière Lyon 2. EvoLyon est un meeting organisé tous les 2 ans et qui rassemble les scientifiques de Lyon intéressés par la thématique de l'évolution, dans un sens très large. C'est toujours un meeting très ouvert où on peut entendre parler aussi bien d'évolution moléculaire que de l'évolution du langage ou de celle de la biodiversité.
Cette année, il y aura deux présentations plénières (Aude BERNHEIM, chercheuse en microbiologie et Luc-Henri FAGE, explorateur, réalisateur), ainsi que six exposés de collègues de la place lyonnaise. De plus, l'édition 2023 abordera une réflexion autour du rôle citoyen des scientifiques au cours d’une table ronde. Vous pouvez trouver le programme provisoire ici: https://evolyon2023.sciencesconf.org/ L'inscription est gratuite mais obligatoire (voir le site web). Il y aura également une session poster et vous pouvez proposer un abstract sur le site web, n'hésitez pas ! |
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Mardi 28/11/2023 Seminar room IBCP Séminaire Externe |
« The challenges of open access in sciences » | |
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Guillaume SESCOUSSE (PhD, centre de recherche en neurosciences de Lyon, PsyR)
Hôte : Elise Lambert
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Mardi 28/11/2023 Mediathèque Paul Zech, Faculté Rockfeller Journée Scientifique |
5ème Journée scientifique - Fédération d’Immunopathologie de Lyon | |
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Lyon Immunopathology Federation
Contacts : Olivier THAUNAT, Alexandre BELOT; Fabienne VENET; Sebastien VIEL; Audrey NOSBAUM; Florence.ADER; Emmanuel BACHY
La Fédération d’Immunopathologie de Lyon (LIFe) a le plaisir de vous informer de la tenue de sa 5ème journée scientifique,
Cette 5ème journée, ouverte à tous (médecins, étudiants et chercheurs), sera l’occasion de partager les travaux scientifiques en immunologie clinique et translationnelle des praticiens et chercheurs des Hospices Civils de Lyon. Comme chaque année, nous vous attendons nombreux, mais attention inscrivez-vous vite les places sont limitées > Inscription gratuite mais obligatoire via le site: https://framaforms.org/formulaire-dinscription-journee-scientifique-2023-de-la-federation-life-hcl-1695718962 |
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Mardi 29/11/2023 Salle SDT CRC Séminaire Externe
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« Developing small molecule inhibitors of Lipoteichoic acid synthesis » | |
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Dr. Maisem LAABEI (University of Bath)
Hôte : Jérome Josse
The lipoteichoic acid (LTA) biosynthesis pathway has emerged as a promising antimicrobial therapeutic target. Previous studies identified the 1,3,4 oxadiazole compound 1771 as an LTA
inhibitor with activity against Gram-positive pathogens. We have succeeded in making multiple 1771 derivatives and, through subsequent hit validation, identified the incorporation of a pentafluorosulfanyl substituent as central in enhancing activity. Our newly described derivative, compound 13, showed a 16- to 32-fold increase in activity compared to 1771 when tested against a cohort of multidrug-resistant Staphylococcus aureus strains while simultaneously exhibiting an improved toxicity profile against mammalian cells. Molecular techniques were employed in which the assumed target, lipoteichoic acid synthase (LtaS), was both deleted and overexpressed. Neither deletion nor overexpression of LtaS altered 1771 or compound 13 susceptibility; however, overexpression of LtaS increased the MIC of Congo red, a previously identified LtaS inhibitor. These data were further supported by comparing the docking poses of 1771 and derivatives in the LtaS active site, which indicated the possibility of an additional target(s). Finally, we show that both 1771 and compound 13 have activity that is independent of LtaS, extending to cover Gram-negative species if the outer membrane is first permeabilized, challenging the classification that these compounds are strict LtaS inhibitors. |
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Mardi 29/11/2023 Salle SDT CRC Séminaire Externe
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« Group A streptococcus and inflammasomes: role of C4BP » | |
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Dr. Serena BETTONI (PostDoc, University of Bath)
Hôte : Jerome Josse
Group A streptococcus (GAS) is a pathogen responsible for over half a million deaths worldwide each year, and currently, there is no available vaccine. In response to GAS infection, human immune cells activate the NLRP3 inflammasome, leading to the secretion of pro-inflammatory cytokines and cell death to eliminate the bacteria.
To evade immune recognition, GAS recruits the complement inhibitor C4b-binding protein (C4BP) to its surface, preventing complement deposition and limiting phagocytosis. Previous research has shown that C4BP can attenuate NLRP3 inflammasome activation in response to various stimuli, such as amyloid fibrils common in type 2 diabetes and insoluble particles responsible for conditions like silicosis and gout. In this study, we investigated the role of C4BP in the inflammasome response to GAS infection. Using primary peripheral blood mononuclear cells and GMCSF-differentiated macrophages, and the reference strain GAS-AP1, we observed that plasma-purified C4BP reduced the IL-1β response, with no effect on cell priming. C4BP was engulfed by cells along with bacteria but excluded from low-pH vesicles. Intracellularly, C4BP localized within the cytosol and near the inflammasome complex but did not inhibit its assembly or activation. The observation that gasderminD cleavage were reduced in the presence of C4BP suggested that NLRP3 inflammasome inhibition by C4BP was due to its interference with caspase-1 activity. Given that the severity of GAS infection is influenced by the amount of IL-1β, our results provide new insights into the effect of C4BP as a potential therapeutic target for controlling the inflammasome response to GAS infection. |
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Jeudi 30/11/2023 Salle SDT CRC Séminaire Externe
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« The Tick Cell Biobank: tick and insect cell lines for vector-pathogen research » | |
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Lesley BELL-SAKYI (University of Liverpool) Hôte : Pierre-Yves Lozach
Continuous cell lines derived from ticks and insects play an essential role in many areas of research into tick-borne viral and bacterial pathogens. The Tick Cell Biobank (TCB) is the world’s only dedicated culture collection for cell lines derived from ticks and other arthropod vectors. Based at the University of Liverpool, the TCB also has Outposts in Malaysia, Kenya, and Brazil. The TCB houses and supplies arthropod cell lines to scientists across six continents, and provides training in their maintenance to ensure successful transfer to, and application in, the recipient laboratory. The TCB also generates and characterizes new cell lines from ticks and insects not already represented in the collection, with a focus on neglected vectors, and maintains a small collection of intracellular arthropod-borne bacteria. Through the provision of these resources, the parent TCB and TCB Outposts underpin international scientific research on vector-borne pathogens and symbionts.
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