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21 mai 2019: 2 événements

  • Département Biologie des Génomes

    Mardi 21 mai 11:00-12:00 - Silvia BULGHERESI - Environmental Cell Biology, University of Vienna, Austria

    Unconventional breakups - the extraordinary reproductive strategies of animal-attached bacteria

    Résumé : Up to now, the study of bacterial growth and division focused on model organisms grown in the laboratory and therefore isolated from their “natural” environment. As a consequence, cell biological research on bacterial symbionts - including those thriving on animal surfaces - is scarce. The spatial disposition of Gammaproteobacteria (Candidatus genus Thiosymbion) on the surface of their marine nematode hosts is species-specific, transgenerationally transmitted from mother to offspring, and likely facilitated by extraordinary reproductive strategies. We are studying their molecular underpinning and seek to understand why they evolved.

    Lieu : Salle des séminaires - bâtiment 26 - campus de Gif-sur-yvette

    En savoir plus : Département Biologie des Génomes
  • Département Microbiologie

    Mardi 21 mai 11:30-12:30 - Hilde De Reuse - Institut Pasteur, Département de Microbiologie, Unité Pathogenèse de Helicobacter, ERL CNRS 6002 PARIS (FRANCE)

    Evolution of Helicobacter and nickel metabolism

    Résumé : Metal acquisition and intracellular trafficking are crucial for all cells and metal ions have been recognized as virulence determinants in bacterial pathogens.
    Helicobacter pylori colonizes the acidic stomach of about half of the human population worldwide and is associated with gastric cancer that is responsible for 800,000 deaths every year. Virulence of Helicobacter pylori depends on the metal nickel, cofactor of two enzymes essential for in vivo colonization. In our group, we are studying the transport, storage and distribution of nickel in H. pylori. I will present the functional characterization of unique nickel-binding proteins of H. pylori that act as nickel stores and are essential for colonization. In addition, I will show our identification of a novel nickel transporter that is also required for colonization. Phylogenomics were applied to study the distribution of these proteins in the Helicobacter genus that is divided into two categories, enterohepatic species and gastric species (such as H. pylori) that exclusively colonize the stomach of mammals.
    Our data show that, during evolution of the Helicobacter genus, acquisition by gastric Helicobacter species of proteins involved in nickel transport and trafficking constituted a decisive evolutionary event to allow Helicobacter to colonize the hostile gastric environment and to become an amazingly successful pathogen.

    Lieu : Salle Kalogeropoulos - Bât. 400, Campus d’Orsay

    En savoir plus : Département Microbiologie