Ref HAL: hal-01493262_v1
Ref Arxiv: 1702.07372
DOI: 10.1103/PhysRevLett.119.028101
WoS: 000405367800016
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
14 Citations
Résumé:

Efficient bacterial chromosome segregation typically requires the coordinated action of a three-component machinery, fueled by adenosine triphosphate, called the partition complex. We present a phenomenological model accounting for the dynamic activity of this system that is also relevant for the physics of catalytic particles in active environments. The model is obtained by coupling simple linear reaction-diffusion equations with a proteophoresis, or “volumetric” chemophoresis, force field that arises from protein-protein interactions and provides a physically viable mechanism for complex translocation. This minimal description captures most known experimental observations: dynamic oscillations of complex components, complex separation, and subsequent symmetrical positioning. The predictions of our model are in phenomenological agreement with and provide substantial insight into recent experiments. From a nonlinear physics view point, this system explores the active separation of matter at micrometric scales with a dynamical instability between static positioning and traveling wave regimes triggered by the dynamical spontaneous breaking of rotational symmetry.

Commentaires: 6 pages, 3 figures

Ref HAL: hal-01950249_v1
Exporter : BibTex | endNote
Résumé:

Bacteria, a few μm in length, have the feature to store the genome in a subvolume of the cell without membrane. The bacterial cell cycle relies on a series of essential processes such as DNA replication, transcription and segregation. The mechanisms driving segregation of the genome are still unclear, mainly because the processes overlap in time and take place in the same cellular compartment. The active ParABS partition system is the only type known on chromosomes and is prevalent on low-copy number plasmids,namely the F-plasmid involved in bacterial resistance to antibiotics. ParABS is composed of three components: the proteins ParA and ParB, respectively a molecular motor (ATPase) and a binding protein, and parS, a sequence of specific binding sites. We describe the organization and architecture of the partition complex. Our model is supported by experimental data from ChIP-sequencing (LMGM, Toulouse) and super resolution microscopy techniques (CBS, Montpellier).

Ref HAL: hal-01950151_v1
Exporter : BibTex | endNote
Résumé:

We model the ParABS system, which is a bacterial DNA Segregation Apparatus.

Ref HAL: hal-01950016_v1
Exporter : BibTex | endNote
Résumé:

We model the ParABS system, which is a bacterial DNA Segregation Apparatus.

Ref HAL: hal-01948428_v1
Exporter : BibTex | endNote
Résumé:

We model the ParABS system, which is a bacterial DNA Segregation Apparatus.

Ref HAL: hal-00749901_v1
Ref Arxiv: 1206.1491
DOI: 10.1016/j.coastaleng.2013.02.008
WoS: WOS:000318325400005
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
11 Citations
Résumé:

In order to study the growth of wind waves in finite depth we extend Miles' theory to the finite depth domain. A depth-dependent wave growth rate is derived from the dispersion relation of the wind/water interface. A suitable dimensionless finite depth wave age parameter allows us to plot a family of wave growth curves, each family member characterized by the water depth. Two major results are that for small wave age, the wave growth rates are comparable to those of deep water and for large wave age, a finite-depth wave-age-limited growth is reached, with wave growth rates going to zero. The corresponding limiting wave length and limiting phase speed are explicitely calculated in the shallow and in the deep water cases. A qualitative agreement with well-known empirical results is established and shows the robust consistency of the linear theoretical approach.

Ref HAL: hal-00819807_v1
Exporter : BibTex | endNote
Résumé:

Nonlinear Supratransmission (NST) was discovered by J. Léon and F. Geniet [Phys. Rev. Lett. 89, 134102 (2002)] in a chain of coupled pendula forced harmonically at one end with a frequency lying within the chain forbidden band gap. When the forcing amplitude is low enough, an evanescent wave is formed that becomes unstable at a critical value above which a sudden energy transfer occurs through the emission of gap solitons: this is NST. This phenomenon has since been observed in many different contexts and in particular in some continuous non integrable multicomponent Nonlinear Schrödinger like models used in Optics. For such models, the NST threshold is a surface whose dimension is equal to the number of components (fields) involved. I shall present an asymptotic method that permits its determination and also talk about an ultra-discrete (monomer) approach that yields both simple and reliable analytical expressions for NST manifolds.