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Octobre 2017

Lundi
02/10/2017
11h

Salle de conférence IBCP

 « Crystal structures of protein-ligand complexes. Tricks and Tips »

Enrico STURA -  (Institut de Biologie et de Technologies de Saclay, Paris)                invited by V. Chaptal

 

Salle de conférence IBCP

Mardi
03 /10 /2017
10h

Salle de conférence IBCP

« Extrinsic or intrinsic? Using renewing organs to understand stem cell regulation »

Frédéric MICHON invité par B Verrier

During development, a complex chain of events regulates cell fate and tissue organization. Within numerous organs stem cells are responsible for the renewal of a part of the organ, insuring its long-term function. Therefore, the formation of renewing organs requires the generation of a niche housing and maintaining the stem cells. Because of aging, disease, or dramatic events, the organ homeostasis collapses, leading eventually to organ failure. To restore the homeostasis, or to replace the whole organ, the tissue-specific stem cell biology needs to be well comprehended.
In the lab, we use the mouse incisor (front tooth), the cornea (transparent surface of the eye) and the lacrimal gland (secreting the tear film) to study the molecular cues involved during stem cell recruitment along organ formation, and their subsequent maintenance and differentiation during the physiological or pathological organ renewal.

 

Mercredi
04/10/2017
11h

Salle Condorcet*

“Natural transformation and cell wall metabolism in Bacillus subtilis”
 

Nicolas MIROUZE (Institut de Biologie Intégrative de la Cellule I2BC) invité par Karen Moreau

Nicolas Mirouze has dedicated his carrier to the study of Horizontal Gene Transfer (HGT) in Gram-positive bacteria. HGT in bacteria may occur via three main mechanisms: transduction, conjugation and genetic transformation. The latter mechanism ensures binding, transport across the cell wall / membrane and homologous recombination of high molecular-weight exogenous DNA with the chromosome of the recipient cell. Genetic transformation is the only of the three mechanisms entirely directed from the recipient cell as all required proteins are encoded in the core chromosome. Expression of genes essential for genetic transformation requires that bacterial cells enter a differentiated state called competence that has been studied in a number of different bacteria.
Nicolas has focused his different projects on the study of natural transformation and competence development in the two main model organisms Streptococcus pneumoniae and Bacillus subtilis and is now interested in Staphyloccocus aureus.
The oral presentation proposed here will particularly describe the early extracellular steps of natural transformation in B. subtilis. Despite decades of investigation, very little was known about exogenous DNA binding at the surface of competent cells and transport across the cell wall. Our results allowed us to understand how the cell wall metabolism is regulated in order to perform natural transformation and to propose an original model (different from what has been suggested in S. pneumoniae) explaining these early extracellular steps in B. subtilis.

* Salle CONDORCET - ex Conférence 1 Place de l’Ecole – Site Monod ENS

Jeudi
05/ 10 / 2017
14h

Salle CRC

“Anticorps monoclonaux antivraux : des immunotherapies passives ou actives ?”

Mireia PELEGRIN - Institut de Génétique Moléculaire -UMR5535 invitée par Floriane Fusil

Les anticorps monoclonaux (AcM) sont considérés avec un intérêt grandissant pour traiter les infections virales graves. Désormais, comprendre les multiples effets des AcM antiviraux représente en enjeu médical majeur avec des conséquences thérapeutiques importantes. En utilisant un modèle murin d’infection rétrovirale, nous avons apporté la preuve de concept qu'une immunothérapie par un AcM antiviral neutralisant peut, non seulement exercer un effet antiviral direct, mais aussi un effet de type « vaccinal » permettant aux animaux infectés de développer une immunité antivirale protectrice à long terme. Nos travaux ont permis d’identifier divers mécanismes moléculaires et cellulaires impliqués dans cet effet immunomodulateur des AcM qui dépend de l’interaction de leurs fragments Fc avec les FcγRs exprimés sur différentes cellules du système immunitaire. Ces observations pourraient conduire à l’amélioration des thérapies antivirales à base d’AcM

Lundi
09 / 10 / 2017
11h

Salle de conférence IBCP

 « A ring-shaped conduit connects mother cell and forespore during bacterial sporulation »

Cécile MORLOT - Insitut de Biologie Structurale invitée par C Grangeasse

During spore formation in Bacillus subtilis a hybrid-like specialized secretion system is assembled across the double membrane that separates the mother cell and the forespore. This transenvelope complex (called the "A-Q complex") is required to maintain forespore development and is composed of proteins with remote homology to components of specialized secretion systems. We have discovered that one of these proteins, SpoIIIAG, assembles into an oligomeric ring with architecture and dimensions similar to those of rings found in Type III secretion systems and flagella. Cryo-EM reconstruction and phenotyping of oligomerization mutants provide strong support for a model in which the SpoIIIAG ring would be part of a A-Q transenvelope conduit connecting the mother cell and the forespore.

Lundi
09 / 10 / 2017
11h00

Salle CRC

« Cardiomyocyte behaviour and genetic compensation in zebrafish »

Didier STANIER - Max Planck Institute, Bad Neuheim

Mardi
10 / 10 / 2017
10h
« Green sperm and eggs evolution of sperm size and post-mating pre-zygotic reproductive isolation »

Asher CUTTER - University of Toronto

Hôte : Marie Delattre

Salle 115 ENS site Monod

 

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