15 results on '"Sigolene Lecuyer"'
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2. Migration of surface-associated microbial communities in spaceflight habitats
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Daniele Marra, Thodoris Karapantsios, Sergio Caserta, Eleonora Secchi, Malgorzata Holynska, Simon Labarthe, Bastien Polizzi, Sandra Ortega, Margaritis Kostoglou, Christophe Lasseur, Ioannis Karapanagiotis, Sigolene Lecuyer, Arnaud Bridier, Marie-Françoise Noirot-Gros, and Romain Briandet
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Biofilm ,Space flight ,Microgravity ,Transcriptomic ,Adaptation ,Evolution ,Biotechnology ,TP248.13-248.65 ,Microbiology ,QR1-502 - Abstract
Astronauts are spending longer periods locked up in ships or stations for scientific and exploration spatial missions. The International Space Station (ISS) has been inhabited continuously for more than 20 years and the duration of space stays by crews could lengthen with the objectives of human presence on the moon and Mars. If the environment of these space habitats is designed for the comfort of astronauts, it is also conducive to other forms of life such as embarked microorganisms. The latter, most often associated with surfaces in the form of biofilm, have been implicated in significant degradation of the functionality of pieces of equipment in space habitats. The most recent research suggests that microgravity could increase the persistence, resistance and virulence of pathogenic microorganisms detected in these communities, endangering the health of astronauts and potentially jeopardizing long-duration manned missions. In this review, we describe the mechanisms and dynamics of installation and propagation of these microbial communities associated with surfaces (spatial migration), as well as long-term processes of adaptation and evolution in these extreme environments (phenotypic and genetic migration), with special reference to human health. We also discuss the means of control envisaged to allow a lasting cohabitation between these vibrant microscopic passengers and the astronauts.
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- 2023
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3. Substrate stiffness impacts early biofilm formation by modulating Pseudomonas aeruginosa twitching motility
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Sofia Gomez, Lionel Bureau, Karin John, Elise-Noëlle Chêne, Delphine Débarre, and Sigolene Lecuyer
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P. aeruginosa ,twitching motility ,colony formation ,substrate stiffness ,Medicine ,Science ,Biology (General) ,QH301-705.5 - Abstract
Surface-associated lifestyles dominate in the bacterial world. Large multicellular assemblies, called biofilms, are essential to the survival of bacteria in harsh environments and are closely linked to antibiotic resistance in pathogenic strains. Biofilms stem from the surface colonization of a wide variety of substrates encountered by bacteria, from living tissues to inert materials. Here, we demonstrate experimentally that the promiscuous opportunistic pathogen Pseudomonas aeruginosa explores substrates differently based on their rigidity, leading to striking variations in biofilm structure, exopolysaccharides (EPS) distribution, strain mixing during co-colonization and phenotypic expression. Using simple kinetic models, we show that these phenotypes arise through a mechanical interaction between the elasticity of the substrate and the type IV pilus (T4P) machinery, that mediates the surface-based motility called twitching. Together, our findings reveal a new role for substrate softness in the spatial organization of bacteria in complex microenvironments, with far-reaching consequences on efficient biofilm formation.
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- 2023
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4. Focus on the physics of biofilms
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Sigolene Lecuyer, Roman Stocker, and Roberto Rusconi
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Science ,Physics ,QC1-999 - Abstract
Bacteria are the smallest and most abundant form of life. They have traditionally been considered as primarily planktonic organisms, swimming or floating in a liquid medium, and this view has shaped many of the approaches to microbial processes, including for example the design of most antibiotics. However, over the last few decades it has become clear that many bacteria often adopt a sessile, surface-associated lifestyle, forming complex multicellular communities called biofilms. Bacterial biofilms are found in a vast range of environments and have major consequences on human health and industrial processes, from biofouling of surfaces to the spread of diseases. Although the study of biofilms has been biologists’ territory for a long time, a multitude of phenomena in the formation and development of biofilms hinges on physical processes. We are pleased to present a collection of research papers that discuss some of the latest developments in many of the areas to which physicists can contribute a deeper understanding of biofilms, both experimentally and theoretically. The topics covered range from the influence of physical environmental parameters on cell attachment and subsequent biofilm growth, to the use of local probes and imaging techniques to investigate biofilm structure, to the development of biofilms in complex environments and the modeling of colony morphogenesis. The results presented contribute to addressing some of the major challenges in microbiology today, including the prevention of surface contamination, the optimization of biofilm disruption methods and the effectiveness of antibiotic treatments.
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- 2015
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5. Continuous versus Arrested Spreading of Biofilms at Solid-Gas Interfaces: The Role of Surface Forces
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Karin John, Uwe Thiele, Sigolene Lecuyer, Sarah Trinschek, LIPHY-DYFCOM, Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Department of Mathematical Sciences [Loughborough], Loughborough University, and Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)
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0301 basic medicine ,Osmosis ,Solid gas ,Materials science ,Surface Properties ,Surface force ,Biofilm ,General Physics and Astronomy ,02 engineering and technology ,Models, Theoretical ,biochemical phenomena, metabolism, and nutrition ,021001 nanoscience & nanotechnology ,Surface tension ,03 medical and health sciences ,030104 developmental biology ,Chemical physics ,Biofilms ,Wettability ,Wetting ,0210 nano-technology ,[PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft] ,ComputingMilieux_MISCELLANEOUS ,Bacillus subtilis - Abstract
We introduce and analyze a model for osmotically spreading bacterial colonies at solid-air interfaces that includes wetting phenomena, i.e., surface forces. The model is based on a hydrodynamic description for liquid suspensions which is supplemented by bioactive processes. We show that surface forces determine whether a biofilm can expand laterally over a substrate and provide experimental evidence for the existence of a transition between continuous and arrested spreading for Bacillus subtilis biofilms. In the case of arrested spreading, the lateral expansion of the biofilm is confined, albeit the colony is biologically active. However, a small reduction in the surface tension of the biofilm is sufficient to induce spreading. The incorporation of surface forces into our hydrodynamic model allows us to capture this transition in biofilm spreading behavior.
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- 2017
6. Focus on the physics of biofilms
- Author
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Roman Stocker, Sigolene Lecuyer, Roberto Rusconi, Massachusetts Institute of Technology. Department of Civil and Environmental Engineering, Stocker, Roman, and Rusconi, Roberto
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Physics ,Biofouling ,Plant growth ,Human health ,Multicellular organism ,Biofilm ,General Physics and Astronomy ,Biochemical engineering ,Liquid medium ,biochemical phenomena, metabolism, and nutrition ,Biofilm growth ,Biological materials - Abstract
Bacteria are the smallest and most abundant form of life. They have traditionally been considered as primarily planktonic organisms, swimming or floating in a liquid medium, and this view has shaped many of the approaches to microbial processes, including for example the design of most antibiotics. However, over the last few decades it has become clear that many bacteria often adopt a sessile, surface-associated lifestyle, forming complex multicellular communities called biofilms. Bacterial biofilms are found in a vast range of environments and have major consequences on human health and industrial processes, from biofouling of surfaces to the spread of diseases. Although the study of biofilms has been biologists' territory for a long time, a multitude of phenomena in the formation and development of biofilms hinges on physical processes. We are pleased to present a collection of research papers that discuss some of the latest developments in many of the areas to which physicists can contribute a deeper understanding of biofilms, both experimentally and theoretically. The topics covered range from the influence of physical environmental parameters on cell attachment and subsequent biofilm growth, to the use of local probes and imaging techniques to investigate biofilm structure, to the development of biofilms in complex environments and the modeling of colony morphogenesis. The results presented contribute to addressing some of the major challenges in microbiology today, including the prevention of surface contamination, the optimization of biofilm disruption methods and the effectiveness of antibiotic treatments., New Journal of Physics, 17, ISSN:1367-2630
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- 2015
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7. Controlling interactions in supported bilayers from weak electrostatic repulsion to high osmotic pressure
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Arnaud Hemmerle, Thierry Charitat, Linda Malaquin, Sigolene Lecuyer, Giovanna Fragneto, Jean Daillant, Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Institut Charles Sadron (ICS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), Synchrotron SOLEIL (SSOLEIL), charitat, thierry, Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), and ILL
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Materials science ,Entropy ,Lipid Bilayers ,Static Electricity ,Aucun ,FOS: Physical sciences ,02 engineering and technology ,Condensed Matter - Soft Condensed Matter ,01 natural sciences ,Ion ,Osmotic Pressure ,0103 physical sciences ,Static electricity ,Osmotic pressure ,Scattering, Radiation ,Physics - Biological Physics ,010306 general physics ,Lipid bilayer ,Condensed Matter - Statistical Mechanics ,ComputingMilieux_MISCELLANEOUS ,Multidisciplinary ,Statistical Mechanics (cond-mat.stat-mech) ,Scattering ,021001 nanoscience & nanotechnology ,Electrostatics ,[PHYS.COND.CM-SCM] Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft] ,Membrane ,Models, Chemical ,Chemical physics ,Biological Physics (physics.bio-ph) ,Physical Sciences ,Soft Condensed Matter (cond-mat.soft) ,0210 nano-technology ,[PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft] ,Order of magnitude - Abstract
Understanding interactions between membranes requires measurements on well-controlled systems close to natural conditions, in which fluctuations play an important role. We have determined, by grazing incidence X-ray scattering, the interaction potential between two lipid bilayers, one adsorbed on a solid surface and the other floating close by. We find that interactions in this highly hydrated model system are two orders of magnitude softer than in previously reported work on multilayer stacks. This is attributed to the weak electrostatic repulsion due to the small fraction of ionized lipids in supported bilayers with a lower number of defects. Our data are consistent with the Poisson-Boltzmann theory, in the regime where repulsion is dominated by the entropy of counter ions. We also have unique access to very weak entropic repulsion potentials, which allowed us to discriminate between the various models proposed in the literature. We further demonstrate that the interaction potential between supported bilayers can be tuned at will by applying osmotic pressure, providing a way to manipulate these model membranes, thus considerably enlarging the range of biological or physical problems that can be addressed., Comment: 14 pages, 8 figures
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- 2012
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8. Correction
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Sigolene Lecuyer, Roberto Rusconi, Yi Shen, Alison Forsyth, Hera Vlamakis, Roberto Kolter, and Howard A. Stone
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Biophysics ,Correction - Published
- 2011
9. Particle/fluid interface replication as a means of producing topographically patterned polydimethylsiloxane (PDMS) surfaces for deposition of lipid bilayers
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Kumaran S. Ramamurthi, Sigolene Lecuyer, Anand Bala Subramaniam, Richard Losick, and Howard A. Stone
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Fabrication ,Materials science ,Polydimethylsiloxane ,Rhodamines ,Mechanical Engineering ,Lipid Bilayers ,Nanotechnology ,Chemical vapor deposition ,Article ,law.invention ,chemistry.chemical_compound ,Cholesterol ,chemistry ,Mechanics of Materials ,law ,Etching (microfabrication) ,Microcontact printing ,Fluorescence Resonance Energy Transfer ,Phosphatidylcholines ,General Materials Science ,Dry etching ,Dimethylpolysiloxanes ,Photolithography ,Microfabrication - Abstract
Microstructured surfaces are common in many materials applications such as microcontact printing,[1,2] biomimetic arrays, [3]controlled-wetting surfaces,[4] superhydrophobic surfaces, [5] and self-cleaning surfaces[6]among others. The majority of strategies for surface fabrication utilize some form of photolithography to achieve patterning. Photolithographic patterning is essentially two-dimensional;[1–4]it does not allow control over geometric parameters in the third dimension such as the surface profile and curvature (the topography) of fabricated features. To overcome the inherent limitations of photolithography, the fabrication of topographically patterned substrates for applications of supported lipid bilayers[7, 8]requires a combination of microfabrication techniques: photolithography followed by anisotropic plasma dry etching and wet oxide etching,[7] or chemical vapor deposition followed by photolithography and chemical etching.[8] These pioneering methods, while successful in producing topographically patterned surfaces capable of imposing gradients of curvature on supported bilayers, are technically complex and require costly clean room or microfabrication facilities. An alternative method is thus desirable, particularly since there is intense interest in the role of curvature in the thermodynamics and dynamics of lipid bilayers[7–11]and membrane proteins[12–14]in the wider fields of biology and physics.
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- 2010
10. Dynamics of Poly( l -lysine) in Hyaluronic Acid/Poly( l -lysine) Multilayer Films Studied by Fluorescence Recovery after Pattern Photobleaching
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Laurent Jourdainne, Jean-Claude Voegel, Pierre Schaaf, Sigolene Lecuyer, Catherine Picart, Bernard Senger, Philippe Lavalle, Youri Arntz, Thierry Charitat, Département de Photochimie Générale (DPG), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS), Institut Gilbert-Laustriat : Biomolécules, Biotechnologie, Innovation Thérapeutique, Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Laboratoire des matériaux et du génie physique (LMGP ), Institut National Polytechnique de Grenoble (INPG)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Sadron (ICS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Biomatériaux et Bioingénierie (BB), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM), Biomatériaux et ingénierie tissulaire, Université Louis Pasteur - Strasbourg I-Institut National de la Santé et de la Recherche Médicale (INSERM), Univ Strasbourg, INSERM, UMR S 1121, F-67085 Strasbourg, France, Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Matériaux et nanosciences d'Alsace (FMNGE), and Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)
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Stereochemistry ,Diffusion ,Population ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Fluorescence ,Electrolytes ,Electrochemistry ,Polylysine ,General Materials Science ,Hyaluronic Acid ,education ,Spectroscopy ,Deposition (law) ,ComputingMilieux_MISCELLANEOUS ,education.field_of_study ,Photobleaching ,Chemistry ,Surfaces and Interfaces ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Polyelectrolyte ,0104 chemical sciences ,Crystallography ,Diffusion process ,0210 nano-technology ,Layer (electronics) ,[PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft] - Abstract
Poly( L-lysine) (PLL)/hyaluronic acid (HA) multilayers are films whose thickness increases exponentially with the number of deposition steps. Such a growth process was attributed to the diffusion, in and out of the whole film, of at least one of the polyelectrolytes constituting the film. In the case of PLL/HA, PLL is known to be the diffusing species. In order to better understand the growth mechanism of such films, it is of primary importance to well characterize the diffusion process of the polyelectrolytes in the multilayer. This process is studied here by fluorescence recovery after pattern photobleaching. We show that the diffusion behavior is different when we consider either PLL chains that are deposited on top of the film or PLL chains embedded in the film, even below only one HA layer. For chains that are embedded, we find two populations: a mobile one with a diffusion coefficient, D, of the order of 0.1 microm(2) x s(-1) and a population that appears immobile ( D < 0.001 microm(2) x s(-1)). For chains deposited on top of the multilayer, a third population appears which is rapidly diffusing ( D congruent with 1 microm(2) x s(-1)). These results confirm the validity of the model generally accepted for the exponential growth process and in particular the existence of up to three subgroups of PLL chains from the point of view of their diffusion coefficient.
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- 2008
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11. Effect of an electric field on a floating lipid bilayer: A neutron reflectivity study
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Thierry Charitat, Sigolene Lecuyer, Giovanna Fragneto, Institut Charles Sadron (ICS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), charitat, thierry, Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), ILL, and Charitat, Thierry
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Lipid Bilayers ,Aucun ,02 engineering and technology ,01 natural sciences ,Surface tension ,chemistry.chemical_compound ,[PHYS.COND.CM-GEN] Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other] ,Biomimetic Materials ,Electrochemistry ,General Materials Science ,Soft matter ,Lipid bilayer ,Phospholipids ,ComputingMilieux_MISCELLANEOUS ,Neutron reflectometry ,Physics::Biological Physics ,Condensed matter physics ,Bilayer ,Surfaces and Interfaces ,021001 nanoscience & nanotechnology ,Amplitude ,0210 nano-technology ,[PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft] ,Algorithms ,Biotechnology ,Materials science ,Membrane Fluidity ,Static Electricity ,Biophysics ,Phospholipid ,FOS: Physical sciences ,Condensed Matter - Soft Condensed Matter ,Quantitative Biology::Subcellular Processes ,Optics ,Electromagnetic Fields ,Electric field ,0103 physical sciences ,Fluctuations ,Surface Tension ,Neutron ,010306 general physics ,Neutrons ,Membranes ,business.industry ,General Chemistry ,87.16.Dg ,87.15.Va ,61.12.Ha ,[PHYS.COND.CM-SCM] Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft] ,chemistry ,[PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other] ,Soft Condensed Matter (cond-mat.soft) ,business ,Bilayers and Vesicles - Abstract
We present here a neutron reflectivity study of the influence of an alternative electric field on a supported phospholipid double bilayer. We report for the first time a reproducible increase of the fluctuation amplitude leading to the complete unbinding of the floating bilayer. Results are in good agreement with a semi-quantitative interpretation in terms of negative electrostatic surface tension., Comment: 12 pages, 7 figures, 1 table accepted for publication in European Physical Journal E Replaced with with correct bibliography
- Published
- 2006
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12. Dynamic Angular Segregation of Vesicles in Electrohydrodynamic Flows.
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William D. Ristenpart, Olivier Vincent, Sigolene Lecuyer, and Howard A. Stone
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- 2010
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13. Shear Stress Increases the Residence Time of Adhesion of Pseudomonas aeruginosa
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Roberto Rusconi, Yi Shen, Alison M. Forsyth, Howard A. Stone, Roberto Kolter, Hera Vlamakis, and Sigolene Lecuyer
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Surface Properties ,Biophysics ,02 engineering and technology ,Molecular Dynamics Simulation ,Flagellum ,medicine.disease_cause ,Bacterial Adhesion ,Pilus ,Fimbriae Proteins ,Microbiology ,Extracellular matrix ,03 medical and health sciences ,medicine ,Shear stress ,Cellular Biophysics and Electrophysiology ,030304 developmental biology ,0303 health sciences ,biology ,Chemistry ,Pseudomonas aeruginosa ,021001 nanoscience & nanotechnology ,biology.organism_classification ,Peptide Fragments ,Extracellular Matrix ,Shear (geology) ,Flagella ,Mutation ,Stress, Mechanical ,0210 nano-technology ,Bacteria - Abstract
Although ubiquitous, the processes by which bacteria colonize surfaces remain poorly understood. Here we report results for the influence of the wall shear stress on the early-stage adhesion of Pseudomonas aeruginosa PA14 on glass and polydimethylsiloxane surfaces. We use image analysis to measure the residence time of each adhering bacterium under flow. Our main finding is that, on either surface, the characteristic residence time of bacteria increases approximately linearly as the shear stress increases (∼0–3.5 Pa). To investigate this phenomenon, we used mutant strains defective in surface organelles (type I pili, type IV pili, or the flagellum) or extracellular matrix production. Our results show that, although these bacterial surface features influence the frequency of adhesion events and the early-stage detachment probability, none of them is responsible for the trend in the shear-enhanced adhesion time. These observations bring what we believe are new insights into the mechanism of bacterial attachment in shear flows, and suggest a role for other intrinsic features of the cell surface, or a dynamic cell response to shear stress.
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14. Fluctuations and destabilization of single phospholipid bilayers
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Thierry Charitat, Sigolene Lecuyer, G. Fragneto, Institut Charles Sadron (ICS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), and ILL
- Subjects
Length scale ,Chemistry(all) ,Phospholipid ,General Physics and Astronomy ,02 engineering and technology ,Physics and Astronomy(all) ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Quantitative Biology::Subcellular Processes ,Biomaterials ,Surface tension ,chemistry.chemical_compound ,Materials Science(all) ,Electric field ,0103 physical sciences ,General Materials Science ,010306 general physics ,ComputingMilieux_MISCELLANEOUS ,Physics::Biological Physics ,Chemistry ,Scattering ,Biochemistry, Genetics and Molecular Biology(all) ,Vesicle ,Bilayer ,General Chemistry ,Lipid bilayer mechanics ,021001 nanoscience & nanotechnology ,Condensed Matter::Soft Condensed Matter ,Crystallography ,Chemical physics ,0210 nano-technology ,[PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft] - Abstract
Supported phospholipid bilayers are interesting model systems for biologists and present fascinating physical properties. The authors present an extensive experimental study of the dynamic properties of supported bilayers. The structure and the equilibrium properties of single and double supported bilayers were investigated with neutron reflectivity. The submicronic fluctuation spectrum of a nearly free “floating” bilayer was determined using off-specular x-ray scattering: the surface tension of the bilayer, its bending modulus, and the intermembrane potential could be determined. Using fluorescence microscopy, the authors showed that this well-controlled single bilayer can form vesicles. Destabilization occurred either at the main gel-fluid transition of the lipids and could be interpreted in terms of a decrease in the bending rigidity or under an ac low-frequency electric field applied in the fluid phase. In the latter case, the authors also studied the effect of the electric field at the molecular length scale by neutron reflectivity. In both cases, destabilization leads to the formation of relatively monodisperse vesicles. This could give further understanding on the vesicle formation mechanism and on the parameters that determine the vesicle size.
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15. Correction
- Author
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Nicolas Autrusson, Sigolene Lecuyer, Roberto Rusconi, Howard A. Stone, and Laura Guglielmini
- Subjects
Chemistry ,Biofilm ,Biophysics ,Correction ,Secondary flow ,Mechanism (sociology) - Full Text
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