Adhesion and biofilms of Pseudomonas aeruginosa are increased under epinephrine stress

International audienc

Control of active turbulence through addressable soft interfaces

We present an experimental study of a kinesin/tubulin active nematic formed at different oil interfaces. By tuning the interfacial rheology of the contacting oil, we have been able to condition and control the seemingly chaotic motion that characterizes the self-sustained active flows in our preparations. The active nematic is inherently unstable and spontaneously develops defects from an initial homogeneous state. We show that the steady state and, in particular, the density and dynamics of the defects strongly depends on the rheology of the contacting oil. Using a smectic-A thermotropic liquid crystal as the oil phase, we pattern the interface thanks to the anisotropy of the shear viscosity in this material. The geometry of the active nematic adapts to the boundary conditions at the interface by changing from the so-called active turbulent regime to laminar flows along the easy flow directions. The latter can be either a lattice of self-assembled circular paths or reconfigurable homogeneous orientations that can be addressed by means of an external magnetic field. We show that, under all confinement conditions, the spatiotemporal modes exhibited by the active liquid are consistent with a single intrinsic length scale, which can be tuned by the material parameters, and obey basic topological requirements imposed on the defects that drive the active flows. Future control strategies, including a tunable depleting agent, are discussed

The absence of SigX may result in a nutritional stress response in Pseudomonas aeruginosa

International audienc

Characterisation of pellicles formed by acinetobacter baumannii at the air-liquidi interface

The clinical importance of Acinetobacter baumannii is partly due to its natural ability to survive in the hospital environment. This persistence may be explained by its capacity to form biofilms and, interestingly, A. baumannii can form pellicles at the air-liquid interface more readily than other less pathogenic Acinetobacter species. Pellicles from twenty-six strains were morphologically classified into three groups: I) egg-shaped (27%); II) ball-shaped (50%); and III) irregular pellicles (23%). One strain representative of each group was further analysed by Brewster's Angle Microscopy to follow pellicle development, demonstrating that their formation did not require anchoring to a solid surface. Total carbohydrate analysis of the matrix showed three main components: Glucose, GlcNAc and Kdo. Dispersin B, an enzyme that hydrolyzes poly-N-acetylglucosamine (PNAG) polysaccharide, inhibited A. baumannii pellicle formation, suggesting that this exopolysaccharide contributes to pellicle formation. Also associated with the pellicle matrix were three subunits of pili assembled by chaperon-usher systems: the major CsuA/B, A1S_1510 (presented 45% of identity with the main pilin F17-A from enterotoxigenic Escherichia coli pili) and A1S_2091. The presence of both PNAG polysaccharide and pili systems in matrix of pellicles might contribute to the virulence of this emerging pathogen

An original phylogenetic approach identified mitochondrial haplogroup T1a1 as inversely associated with breast cancer risk in BRCA2 mutation carriers

Introduction: Individuals carrying pathogenic mutations in the BRCA1 and BRCA2 genes have a high lifetime risk of breast cancer. BRCA1 and BRCA2 are involved in DNA double-strand break repair, DNA alterations that can be caused by exposure to reactive oxygen species, a main source of which are mitochondria. Mitochondrial genome variations affect electron transport chain efficiency and reactive oxygen species production. Individuals with different mitochondrial haplogroups differ in their metabolism and sensitivity to oxidative stress. Variability in mitochondrial genetic background can alter reactive oxygen species production, leading to cancer risk. In the present study, we tested the hypothesis that mitochondrial haplogroups modify breast cancer risk in BRCA1/2 mutation carriers. Methods: We genotyped 22,214 (11,421 affected, 10,793 unaffected) mutation carriers belonging to the Consortium of Investigators of Modifiers of BRCA1/2 for 129 mitochondrial polymorphisms using the iCOGS array. Haplogroup inference and association detection were performed using a phylogenetic approach. ALTree was applied to explore the reference mitochondrial evolutionary tree and detect subclades enriched in affected or unaffected individuals. Results: We discovered that subclade T1a1 was depleted in affected BRCA2 mutation carriers compared with the rest of clade T (hazard ratio (HR) = 0.55; 95% confidence interval (CI), 0.34 to 0.88; P = 0.01). Compared with the most frequent haplogroup in the general population (that is, H and T clades), the T1a1 haplogroup has a HR of 0.62 (95% CI, 0.40 to 0.95; P = 0.03). We also identified three potential susceptibility loci, including G13708A/rs28359178, which has demonstrated an inverse association with familial breast cancer risk. Conclusions: This study illustrates how original approaches such as the phylogeny-based method we used can empower classical molecular epidemiological studies aimed at identifying association or risk modification effects.Peer reviewe

Dynamique de constitution des compétences d'innovation dans une FMN. Le cas Valeo.

This thesis focuses on the way multinational corporations (MNCs) develop and manage the required competences to sustain their innovation strategy when their market dynamism is shifting towards Asia.The literature presents various models to organize innovation processes globally but does not answer the question of their dynamic constitution based on a given situation.Drawing upon an interactive research conducted within Valeo – a worldwide automotive supplier – this thesis focuses on that dynamic dimension. It sheds light on how (i) China constitutes a disruptive experience for the Western MNC because of the speed and scale of the phenomenon, as well as the context, (ii) the strategy implemented by the MNC in China from Europe has helped to deal with the difficult situation in the short term, but is not the best way to develop the necessary competences locally to enable the local teams to become autonomous.We thus suggest: (i) at the micro level, a new way of designing training programs that involves shifting from a teaching-centered approach to a learning-centered approach, (ii) at the macro level, a trajectory to improve the constitution of R-I-D (Research, Innovation, Development) competences in the global firm, on the one hand in China via the coaching of local trainers and the development of communities of practice, and on the other hand globally via the constitution of an organizational vehicle such as a Corporate University, to address simultaneously learning and talent management issues – both individually & collectively, locally & globally, in-house & in link with the outside world.La thèse traite de la manière dont des firmes multinationales (FMNs) historiquement occidentales, pilotent la dynamique de constitution des compétences nécessaires pour supporter leur stratégie de croissance et d’innovation, lorsque leur marché bascule depuis l’Europe vers l’Asie.La littérature sur le management de l’innovation dans les FMNs propose différents modèles d’organisation globale des processus d’innovation mais n’aborde pas la question de la dynamique de constitution de ces modèles, à partir d’une situation historique et d’une stratégie d’internationalisation spécifique.La thèse traite de cette question de la dynamique à partir d’une recherche interactive menée au sein de l’équipementier automobile mondial Valeo. Elle montre (i) que l’internationalisation en Chine constitue une triple rupture de vitesse, de volume ainsi que de contexte pour la FMN occidentale historique, (ii) que la stratégie mise en œuvre par la FMN en Chine depuis l’Europe permet de gérer la situation à court terme, mais n’est pas particulièrement propice à la constitution des compétences nécessaires aux équipes locales pour devenir progressivement autonomes.A partir d’un diagnostic des difficultés rencontrées, la thèse propose alors (i) au niveau micro, un modèle de reconception des dispositifs de formation dispensés, de manière à optimiser les apprentissages des collaborateurs chinois et favoriser le développement de leurs compétences, (ii) au niveau macro, une trajectoire d’optimisation du développement des compétences de R-I-D (Recherche, Innovation, Développement) dans la firme-réseau global, d’une part en Chine via la formation de formateurs locaux et la constitution de communautés de pratiques, d’autre part globalement via la constitution d’un véhicule organisationnel de type Université d’Entreprise, qui permettrait d’adresser, ensemble, les problématiques d’identification et d’attrait des talents, de montée en compétence, ainsi que d’engagement et de fidélisation

Constitution of innovation competences in a multinational corporation. Valeo case study.

La thèse traite de la manière dont des firmes multinationales (FMNs) historiquement occidentales, pilotent la dynamique de constitution des compétences nécessaires pour supporter leur stratégie de croissance et d’innovation, lorsque leur marché bascule depuis l’Europe vers l’Asie.La littérature sur le management de l’innovation dans les FMNs propose différents modèles d’organisation globale des processus d’innovation mais n’aborde pas la question de la dynamique de constitution de ces modèles, à partir d’une situation historique et d’une stratégie d’internationalisation spécifique.La thèse traite de cette question de la dynamique à partir d’une recherche interactive menée au sein de l’équipementier automobile mondial Valeo. Elle montre (i) que l’internationalisation en Chine constitue une triple rupture de vitesse, de volume ainsi que de contexte pour la FMN occidentale historique, (ii) que la stratégie mise en œuvre par la FMN en Chine depuis l’Europe permet de gérer la situation à court terme, mais n’est pas particulièrement propice à la constitution des compétences nécessaires aux équipes locales pour devenir progressivement autonomes.A partir d’un diagnostic des difficultés rencontrées, la thèse propose alors (i) au niveau micro, un modèle de reconception des dispositifs de formation dispensés, de manière à optimiser les apprentissages des collaborateurs chinois et favoriser le développement de leurs compétences, (ii) au niveau macro, une trajectoire d’optimisation du développement des compétences de R-I-D (Recherche, Innovation, Développement) dans la firme-réseau global, d’une part en Chine via la formation de formateurs locaux et la constitution de communautés de pratiques, d’autre part globalement via la constitution d’un véhicule organisationnel de type Université d’Entreprise, qui permettrait d’adresser, ensemble, les problématiques d’identification et d’attrait des talents, de montée en compétence, ainsi que d’engagement et de fidélisation.This thesis focuses on the way multinational corporations (MNCs) develop and manage the required competences to sustain their innovation strategy when their market dynamism is shifting towards Asia.The literature presents various models to organize innovation processes globally but does not answer the question of their dynamic constitution based on a given situation.Drawing upon an interactive research conducted within Valeo – a worldwide automotive supplier – this thesis focuses on that dynamic dimension. It sheds light on how (i) China constitutes a disruptive experience for the Western MNC because of the speed and scale of the phenomenon, as well as the context, (ii) the strategy implemented by the MNC in China from Europe has helped to deal with the difficult situation in the short term, but is not the best way to develop the necessary competences locally to enable the local teams to become autonomous.We thus suggest: (i) at the micro level, a new way of designing training programs that involves shifting from a teaching-centered approach to a learning-centered approach, (ii) at the macro level, a trajectory to improve the constitution of R-I-D (Research, Innovation, Development) competences in the global firm, on the one hand in China via the coaching of local trainers and the development of communities of practice, and on the other hand globally via the constitution of an organizational vehicle such as a Corporate University, to address simultaneously learning and talent management issues – both individually & collectively, locally & globally, in-house & in link with the outside world

Exoproteomics for Better Understanding Pseudomonas aeruginosa Virulence

International audiencePseudomonas aeruginosa is the most common human opportunistic pathogen associated with nosocomial diseases. In 2017, the World Health Organization has classified P. aeruginosa as a critical agent threatening human health, and for which the development of new treatments is urgently necessary. One interesting avenue is to target virulence factors to understand P. aeruginosa pathogenicity. Thus, characterising exoproteins of P. aeruginosa is a hot research topic and proteomics is a powerful approach that provides important information to gain insights on bacterial virulence. The aim of this review is to focus on the contribution of proteomics to the studies of P. aeruginosa exoproteins, highlighting its relevance in the discovery of virulence factors, post-translational modifications on exoproteins and host-pathogen relationships

Editorial: Bacterial Post-translational Modifications

International audienc

Post-translational modifications in Pseudomonas aeruginosa revolutionized by proteomic analysis

International audienc