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6 novembre 2020: 3 événements

  • Département Microbiologie

    Vendredi 6 novembre 09:30-10:30 - Olivier BORKOWSKI - Institut Pasteur, Paris

    Relationship between gene expression and host physiology in bacteria and yeast

    Résumé : My scientific interest, from my PhD to my current work, focuses on the relationship between cell physiology and gene expression. During my PhD, I worked on B. subtilis to understand the impact of growth rate on protein production using a system-oriented approach. Then, during my postdocs, I focused on the impact of protein production on the growth rate. I developed a method to predict the cost of heterologous protein production using cell-free systems (in vitro expression) and models of the translation process. In parallel, I used synthetic biology approaches to build :
    -  Genetic circuits sensing the changes in cell physiology in different growth phases to control protein production in E. coli using genetic logic gates
    -  Autonomous "feedback control" circuits to sense and reduce the weight of resource competition between the host and synthetic circuits
    I also coupled cell-free systems and active learning to maximize protein production and highlight the critical resources limiting gene expression in vitro. Today, I am working on active learning as a general tool to assist the design of genetic circuits in S. cerevisiae.
    I am currently developing a project to build a platform to easily express and study gene expression of difficult to grow/transform non-model organisms. Non-model organisms represent the vast majority of bacteria in nature and are poorly understood. On the contrary, it is now fast and easy to express gene by adding DNA in cell-free expression systems. The literature contains a collection of well-established protocols to obtain cell-free systems from multiple model bacteria.
    This project aims to use these cell-free systems and a library of plasmids to emulate the transcription machineries of “uncultivable” organisms. Such approach will be adaptable to a variety of new organisms as long as the genes involved in the transcription processes are well-annotated to build the suitable plasmids library. Eventually, with this platform, I should be able to express complete genomes to provide large transcriptome datasets and identify new genes, regulations and pathways but also to develop new genetic tools to manipulate these organisms.

    Lieu : En visio

    En savoir plus : Département Microbiologie
  • Evènements I2BC

    Vendredi 6 novembre 11:00-12:30 - Mart Krupovic - Institut Pasteur, Paris

    Living on the edge : the secrets of archaeal viruses

    Résumé : Viruses of archaea represent one of the most enigmatic parts of the virosphere. Most of the characterized archaeal viruses infect extremophilic hosts and display remarkable diversity of virion morphotypes, many of which have never been observed among bacteriophages or viruses of eukaryotes. However, recent environmental studies have shown that archaeal viruses are widespread also in moderate soil and marine ecosystems, where they play an important ecological role by influencing the turnover of microbial communities, with a global impact on the carbon and nitrogen cycles. During the seminar, I will present the recent advances in our understanding of the genomic and morphological diversity of archaeal viruses and the mechanisms of virus-host interactions in Archaea. I will highlight some of the molecular adaptations underlying the stability of archaeal viruses in extremely hot acidic environments. Finally, I will examine the potential origins and evolution of archaeal viruses and discuss their place in the global virosphere.

    Lieu : Visio - https://uvsq-fr.zoom.us/j/92861689942?pwd=N3h2alA1VWcrUTNvenNrb2pNWWk0Zz09

    Notes de dernières minutes : Ce séminaire est donné dans le cadre d’un enseignement de M2 hébergé par l’I2BC. Contact : Ombeline Rossier (ombeline.rossier@i2bc.paris-saclay.fr)

    En savoir plus : Evènements I2BC
  • Département Biochimie, Biophysique et Biologie Structurale

    Vendredi 6 novembre 11:00-12:00 - Valérie Biou - Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, Institut de Biologie Physico-Chimique

    Energy supply of heme import in bacteria : Cryo-EM structures of two membrane complexes

    Résumé : Gram negative bacteria import iron from their host cells via a two-membrane spanning complex energised by a TonB-like complex in the inner membrane. We solved the structures of two partners of TonB from Serratia marcescens : ExbB pentamer and its complex with ExbD. The structures show the detailed location of the partners and exhibit differences with respect to the E. coli complex.

    Lieu : Amphithéatre de Neurospin, CEA Saclay - https://joliot.cea.fr/drf/joliot/Pages/Entites_de_recherche/neurospin/Plan-neurospin.aspx

    En savoir plus : Département Biochimie, Biophysique et Biologie Structurale