Soutenances

Congratulations to our new FdV Doctor Yann LE CUNFF who graduated on March 27th 2012 at the Institut Jacques Monod.

Thesis title: "Between Evolution and Demography"
"Le vieillissement: Entre Evolution et Démographie"

Abstract:
Aging is a complex, multiscale issue, at the interface between evolution and demography. The disposable soma theory, an evolutionary theory of aging, proposes that trade-offs between maintenance and reproduction drive aging. Despite its success at describing similarities in aging at the individual level, the disposable soma theory does not provide insights about mortality patterns observed across species. By contrast, biodemographic studies of aging show that population heterogeneity explains these mortality patterns. Yet, they do not address whether population heterogeneity derives from evolutionary processes. In this PhD thesis, I propose to bridge these gaps in five steps. First, I tackle the evolution of biological networks to show that natural selection leads to increased robustness to perturbations. Second, I introduce costs for reproduction in this model : individual robustness now co-evolves with population stability. Third, damage is allowed to accumulate over age. Each individual has its own resource allocation strategy between maintenance and reproduction. The distribution of strategies in the population evolves over generations in response to environmental constraints: evolved populations display mortality patterns which reproduce those of yeast, worms, flies and humans. Fourth, the model predicts population heterogeneity for different forms of trade-offs and different stress conditions. Fifth, an evolutionary framework is proposed to account for the evolution of heterogeneity: any heritable information should be described as a distribution of possible phenotypes. The effect of natural selection only consists in shaping this distribution.

Congratulations to our new FdV Doctor Philippe BUN who graduated on February 24th 2012 at the Institut Jacques Monod.

Thesis title : "Symmetry breaking and Cell polarization imposed by an external mechanical cue"



Abstract:
Cell polarity establishment implies a symmetry-breaking event, resulting in an axis along which the cell reorganizes. Studies on morphogenesis and cytokinesis reveal the implication of the cortical actomyosin contractility in cell shape changes. Whether the initial event that triggers polarity arises spontaneously or requires an external cue remains controversial. Here we show that single and weak integrin-mediated mechanical cue applied on detached round fibroblasts is required to control the location and duration of symmetry breaking of cortical actomyosin gel instability. Furthermore, we demonstrate that cells respond at a macroscopic level since the induced asymmetric actomyosin flow triggers the 3D migratory polarization axis and determines its orientation.
As an initial event, the microtubule-independent actomyosin flow polarizes towards the opposite pole of the cue and drives higher contractility at the rear of the cell that persists after the application of mechanical stress has been halted. Microtubules are further required for long-term growth of leading edge protrusion associated with the MTOC reorientation relative to the cue. These findings support a model whereby the stochastic and transient symmetry breaking events occurring in detached oscillating cells are not able to drive cell polarity establishment, the mechanical stress being required to trigger processes of global auto organization required for long-term functional polarization. The symmetry breaking bias mechanism revealed here in single cells likely emerges as a relevant mechanism for other key processes occurring in tissue morphogenesis.

Thesis supervisor: Maïté COPPEY-MOISAN (DIRECTEUR DE RECHERCHE)

Congratulations to our new FdV Doctor Thomas COURTAT who graduated on Januray 31st 2012 at the MSC Lab of Paris Diderot university.

Thesis title : "Promenade dans les cartes de ville, Phénoménologie mathématique et physique de la ville - une approche géométrique" - (thesis defense in french)

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Congratulations to our new FdV Doctor Nicolas TCHITCHEK who presented his thesis defense on december 19th 2011 at the CRI.

Title : Novel statistical and geometrical methods for integrative genomics

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Congratulations to our new FdV Doctor José Felipe GOLIB DZIB who presented his thesis defense on Friday 16 december 2011 at the IHES (Bures sur Yvette).

Title : Biologie des Systèmes de l'Hyperaldostéronisme Primaire / Systems Biology of Primary Aldosteronism

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Congratulations to our new FdV Doctor, Pierre-Jean ARDUIN, who graduated on december 2011

Thesis title : Operant conditioning of neurons in the rat motor cortex for a graded control of a prosthetic device

Titre de la thèse (french) : Conditionnement opérant de neurones du cortex moteur du rat pour un contrôle gradué de prothèse

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Congratulations to our new FdV Doctor Alexandre GREMIAUX who graduated on November 30th 2011 at INRA.

Title : Sex-pheromone representation in the moth olfactory pathway : From data analysis to model.

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Congratulations to our new FdV Doctor Nebraska ZAMBRANO who graduated on November 30th 2011 at the CRI.

Title : Combining Modified Metallothionein and Europium as Label for Correlative Microscopy

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Congratulations to our new FdV Doctor Mathieu THOMAS who graduated on November 29th 2011.

Title (french) : "Gestion dynamique à la ferme de l'agrobiodiversité : relation entre la structure des populations de blé tendre et les pratiques humaines".

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Congratulations to our new FdV Doctor Alexandre ROLAND who graduated on November 29th 2011 at ESPCI ParisTech.

Title : Endocannabinoïdes et plasticité structurale : dynamique de la signalisation et du remodelage en aval du récepteur cannabinoïque de type 1 à l'échelle de la cellule unique.

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Congratulations to our new FdV doctor Tiffany LIEURY, who graduated on 28 Nov. 2011 at the CRI.

Title (french) : Transitoires calciques présynaptiques induits par dépolarisation membranaire: amélioration des méthodes dédiées à leur détection automatique et à leur analyse.

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Congratulations to our new FdV Doctor Tamara MILOSEVIC who graduated on november 21st 2011 at the CRI.

Title : Yeast pathology - a systemic analysis of death and aging in budding yeast

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Congratulations to our new FdV doctor Francesca ANSELMI, who graduated with the "very honourable" grade and Congratulations of the jury on november 4th 2011.

Thesis title : Advanced optical methods for brain activity control

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Congratulations to our new doctor Xavier Manière who graduated on November 2nd 2011

Thesis defense of Xavier Manière, INSERM U1001, Faculté de médecine Université Paris Descartes

PhD title : Phenotipic variability in Caenorhabditis aging.
Scientific domain : Aging biology

Members of the jury:

Président : Jacques Tréton, DR1 Paris Descartes
Rapporteurs:
Hugo Aguilaniu, CR1 CNRS, École Normale Supérieure de Lyon
Daryl Shanley, Senior Lecturer, Institute for Ageing and Health Newcastle University
Éxaminateurs:
Marie-Anne Félix, Professeur à l' École Normale Supérieure
Olivier Nosjean, Institut de Recherche Servier
Directeur de thèse:
Ivan Matic, DR1 CNRS

Summary/Résumé

Congratulations to our new FdV Doctor Quentin Perrenoud who graduated on October 24th 2011 with congratulations of the Jury !

Thesis : Diversity of neocortical interneurons

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Congratulations to our new doctor Mael Montevil who graduated with the very Honourable grade and congratulations of the Jury on October 7th 2011



Thesis title : Biological time and extended critical transitions : towards and objectivization of the living state of matter.

Abstract :

Congratulations to our new doctor Getao SHI who graduated with the very remarkable grade on October 17th 2011



Thesis title : Development of functional proteomics approcahes for studying retrograde transport
The thesis defense took place at 9:30am on October 17th 2011 in Amphithéâtre Constant Burg(downstairs of the building) of Curie Institute.

Abstract :

Congratulations to our new doctor Kevin Ho Wan with the very Honourable grade and congratulations of the Jury on September 30th 2011



Thesis title : Single-Molecule Studies of the Bacterial Transcription Coupled Repair Process

Abstract :

Transcription coupled repair (TCR), a sub-pathway of the nucleotide excision repair mechanism, is activated when a RNA polymerase (RNAP) is arrested during transcription by DNA damage. TCR is a ubiquitous cellular response important for maintenance of DNA integrity. Some human genetic disorders are associated with defect on TCR, like the Cockayne syndrome for instance. In the bacterium Escherichia coli, TRCF, the product of the mfd gene, is the DNA translocase that couples transcription and DNA repair: it recognizes a stalled ternary elongation complex, dissociates it, and recruits the UvrABC repair machinery.
We used a single molecule approach, by means of magnetic tweezers, to study the initiation of TCR and monitored the dissociation of individual RNAPs by individual TRCFs in real time. We have identified that TRCF acts on stalled RNAP by remodeling the transcription bubble in two successive ATP-dependent steps separated by a novel intermediate denoted RD*.
Statistical analysis of the time required to dissociate the stalled RNAP at different concentrations of TRCF has shown that the displacement of the ternary elongation complex is a three limiting-steps process: (i) recruitment of TRCF to the stalled RNAP, (ii) activation of TRCF and initiation of the dissociation of RNAP by rewinding of 2/3 of the "transcription bubble", and (iii) complete dissociation of the elongation complex. The intermediate complex RD* formed after the first step of rewinding is characterized by a long lifetime, which suggests that it would behave as a temporally reliable marker, enabling the recruitment of the UvrABC repair machinery to the damaged site.

Congratulations to our new doctor Kathleen Zylbersztejn who graduated with the very Honourablme grade and congratulations of the Jury on September 15th 2011


Kathleen Zylbersztejn (left) with PhD colleagues Lydia, Maja, Imène and Francesca (FdV).

Thesis title : role of vesicular traffic in axon guidance

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Congratulations to our new doctor Ruben Elisée who graduated with congratulations of the Jury !

His thesis defense took place on September 9th 2011 in the Pasteur Institute in Paris.

Thesis title
Analysis of mitochondrial metabolism in response to peptidoglycan in epithelial cell"
(in french) : "La réponse métabolique de cellules épithéliales au peptidoglycane"

Noah Hardy, FdV teacher, had the chance to attend Ruben Elisée's thesis defense and wrote us a report of this Event :