Programme : séminaires et soutenances - Septembre 2014

Programme : séminaires et soutenances - Septembre 2014

Département de Microbiologie,
Institut Pasteur, 25 rue du Dr Roux - 75015 Paris


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. vendredi 5 septembre 2014, 11:30 : séminaire Claire POYART (Institut Cochin, Paris)


. vendredi 12 septembre 2014, 11:30 : séminaire Kristina JONAS (Philipps University  (Marburg, Germany)


. lundi 15 septembre 2014, 11:30 : soutenance de thèse Peng LIU (unité Génétique Moléculaire, IP Paris)


. vendredi 19 septembre 2014, 9:45 : soutenance de thèse Kasie RAYMANN (unité Biologie Moléculaire du Gène chez les Extrêmophiles, IP Paris)


. vendredi 26 septembre 2014, 11:30 : séminaire Yves BRUN (Indiana University, Bloomington, USA)




Séminaire présenté par : Claire POYART

Institut Cochin team INSERM “Barriers and pathogens”

Centre National de Référence des streptocoques,

Hôpitaux Universitaires Paris Centre, site Cochin, APHP


'Deciphering the hypervirulence of ST 17 Group B Streptococcus'


vendredi 5 septembre 2014 à 11 h 30

Auditorium François Jacob – Centre F. Jacob


contact : Christophe Beloin (



Streptococcus agalactiae (Group B Streptococcus, GBS), a normal constituent of the intestinal microbiota is the major cause of human neonatal infections and the worldwide spread « hypervirulent » clone, GBS ST-17, is strongly associated with neonatal meningitis. GBS surface-anchored proteins are obvious potential adhesion mediators of barrier crossing and determinants of hypervirulence. This seminar will address the most recent molecular insights gained from studies on GBS surface proteins proven to be involved in the infectious process and will emphasize on the specificity of the hypervirulent clone displaying meningeal tropism.




Séminaire présenté par : Kristina JONAS

LOEWE Center for Synthetic Microbiology, Philipps University  (Marburg, Germany)


'How bacteria make decisions : mechanisms of prokaryotic cell cycle control'


vendredi 12 septembre 2014 à 11 h 30

Changement de salle: Amphithéâtre Jacques Monod


contact : Ambroise Lambert (



Whether to divide or not to divide is an important decision that most cells have to make, in particular unicellular organisms that are exposed to rapidly changing environments. In this talk I will focus on the molecular mechanisms that coordinate this decision in bacteria. By using Caulobacter crescentus as a model system, our recent work revealed that regulated proteolysis of key regulatory proteins provides a means by which cells can adjust their proliferative program in response to adverse growth conditions. For example, our data suggest that stress conditions that cause perturbations of the protein global folding state can reprogram the substrate selectivity of a cellular protease and in this way ensure rapid clearance of a highly conserved regulator required for DNA replication and proliferation. I will talk about this and other regulatory mechanisms that transduce environmental signals into the cell cycle machinery. Furthermore, I will discuss how insight into the general rules of cellular decision-making can be adopted for re-programming bacterial behaviors in synthetic biology settings.




Soutenance de thèse : Université Paris VII - Diderot

Ecole Doctorale Biochimie, Biothérapies, Biologie moléculaire et Infectiologie (B3MI)


Peng LIU


'Etude du mécanisme d'activation de MalT, une protéine signalisatrice de type STAND'


sous la direction d'Evelyne RICHET, Unité de Génétique Moléculaire dirigée par Anthony PUGSLEY  Département de Microbiologie, Institut Pasteur - CNRS ERL 3526


Lundi 15 septembre 2014 à 14 h 00

salle Jules Bordet - rdc Bâtiment Metchnikoff


contact : Peng LIU (




Soutenance de thèse : Université Pierre et Marie Curie - "Pasteur-Paris University International Doctoral Program" (PPU)

Ecole doctorale Complexité du Vivant




'Reconstructing the evolutionary relationships between Archaea and Eukaryotes : a phylogenomic approach'


vendredi 19 septembre 2014 à 9 h 45

Grand Amphithéâtre Duclaux – Bâtiment Duclaux


sous la direction de Simonetta GRIBALDO

Unité Biologie Moléculaire du Gène chez les Extrêmophiles dirigée par Patrick FORTERRE Département de Microbiologie, Institut Pasteur


contact : Kasie Raymann (




Séminaire présenté par : Yves BRUN

Indiana University (Bloomington, USA)


'Mechanisms and regulation of bacterial surface attachment and biofilm formation'


vendredi 26 septembre 2014 à 11 h 30

Auditorium François Jacob – Centre F. Jacob


contact : Christophe Beloin (



The attachment of bacteria to surfaces provides advantages such as increasing nutrient access and resistance to environmental stress. Attachment begins with a reversible phase, often mediated by surface structures such as flagella and pili, followed by a transition to irreversible attachment, typically mediated by polysaccharides. The seminar will focus on stimulatory and inhibitory mechanisms of cell attachment and biofilm formation. I will describe how the interplay between pili and flagellum rotation of Caulobacter crescentus cells stimulates the rapid transition between reversible and polysaccharide-mediated irreversible attachment by stimulating the biosynthesis of the holdfast adhesive polysaccharide. I will also describe how programmed cell death in a biofilm produces extracellular DNA that inhibits cell settling in the biofilm by directly binding to nascent holdfast, thereby stimulating cell dispersal in response to declining environmental quality.

Li, G., Brown, P.B., J.X. Tang, Zhu, J., Quardokus, E.M., Fuqua, C., and Y.V. Brun.  2012.  Surface contact stimulates the just-in-time deployment of bacterial adhesins.  Molecular Microbiology, 83:41-51.

Berne, C., D. Kysela, and Y.V. Brun. 2010.  A bacterial extracellular DNA inhibits settling of motile progeny cells within a biofilm.  Molecular Microbiology, 77: 815-829. 


C. Berne, X. Ma, N. Licata, B. Neves, S. Setayeshgar, Y.V. Brun, and B. Dragnea. 2013. Physiochemical Properties of Caulobacter crescentus Holdfast: a Localized Bacterial Adhesive. Journal of Physical Chemistry, 117: 10492-503.


Javens, J.J., Z. Wan, G.G. Hardy, and Y.V. Brun. 2013. Bypassing the need for subcellular localization of a polysaccharide export-anchor complex by overexpressing its protein subunits. Molecular Microbiology, 89: 350-71.


Mis à jour le 09/09/2014


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