Laboratoire Léon Brillouin

UMR12 CEA-CNRS

Bât. 563 CEA Saclay

91191 Gif sur Yvette Cedex

France

llb-sec@cea.fr

PhD subjects

Dernière mise à jour : 22-11-2017

2 sujets IRAMIS/LLB

• Molecular biophysics

• Solid state physics, surfaces and interfaces

 

DNA compaction induced by a bacterial amyloid

SL-DRF-18-0270

Research field : Molecular biophysics
Location :

Laboratoire Léon Brillouin (LLB)

Groupe Biologie et Systèmes Désordonnés

Saclay

Contact :

Véronique ARLUISON

Starting date : 01-09-2018

Contact :

Véronique ARLUISON

Université Paris VII - DRF/IRAMIS/LLB/GBSD

01 69 08 32 82

Thesis supervisor :

Véronique ARLUISON

Université Paris VII - DRF/IRAMIS/LLB/GBSD

01 69 08 32 82

Personal web page : http://www-llb.cea.fr/Phocea/Membres/Annuaire/index.php?uid=varluiso

Laboratory link : http://www-llb.cea.fr/

More : https://www.synchrotron-soleil.fr/

In bacteria, the genetic material is often in a crowded and congested state. For instance, the size of the bacterial nucleoid, the structure that contains the bacterial chromosome associated with proteins, is typically sub-micron whereas the length of the DNA is around 1 mm. The genome is hence compacted by a factor of thousand.

Expected breakthroughs of the PhD project are to develop and to couple methods for the investigation of nucleoprotein structures. A multidisciplinary approach will be developed at the Leon Brillouin laboratory in collaboration with a group at SOLEIL Synchrotron (DISCO beamline). The PhD student will investigate the effect of protein-mediated bridging on the structural properties of bacterial DNA. In particular, we aim to study a new way of DNA structuring by a bacterial protein forming amyloid structures, called Hfq. DNA condensation induced by amyloids associated to neuropathologies has been reported previously. Here the amyloid domain of Hfq serves the physiology of the cell to ensure DNA compaction. Examining the interaction of Hfq with DNA will thus be paramount for understanding bacterial nucleoid compaction and functional consequences. The expected benefits for this PhD project will be twice: the development of methods for the analysis of biological nanostructures, but also new opportunities for the development of antibiotics.

Exploring spin fluctuations in photosensitive molecules

SL-DRF-18-0416

Research field : Solid state physics, surfaces and interfaces
Location :

Laboratoire Léon Brillouin (LLB)

Groupe Interfaces et Matériaux (GIM)

Saclay

Contact :

Gregory CHABOUSSANT

Starting date : 01-10-2018

Contact :

Gregory CHABOUSSANT

CNRS-UMR 12 - LLB - Laboratoire de Diffusion Neutronique

01 69 08 96 51

Thesis supervisor :

Gregory CHABOUSSANT

CNRS-UMR 12 - LLB - Laboratoire de Diffusion Neutronique

01 69 08 96 51

Personal web page : http://iramis.cea.fr/Pisp/gregory.chaboussant/

Laboratory link : http://www-llb.cea.fr/

In the general framework of nanomagnetism, this research subject deals with fundamental properties of new magnetic materials (molecular magnetic clusters, magnetic nanoparticles) displaying very interesting functional properties like photo-commutation or the precise control of magnetization at the molecular level (data storage).



These “switchable” molecular solids are promising materials for high-density optical memory devices. Molecular materials with so-called “spin transition” properties are capable to drastically change their magnetic state upon temperature variation or under light radiation (photomagnetism). This transition is induced by an electronic state conversion of the magnetic atoms (from low-spin to high-spin state).



We have undertaken study using Small Angle Neutron Scattering (SANS) to probe structural and magnetic properties of coordination nanoparticles (CNPS’s) which are novel systems that open new possibilities for the design of molecule-based bistable objects where magnetism may be controlled or tuned by an external perturbation (light, temperature, field, etc.). Neutron scattering experiments will be carried out at the LLB neutron source (CEA Saclay, south of Paris) and/or at the Institute Laue-Langevin (Grenoble).

 

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