A5027110766- Bacterial biofilms and quorum sensing
- Bacterial Genetics and Biotechnology
- Vibrio bacteria research studies
- Plant-Microbe Interactions and Immunity
- Plant Pathogenic Bacteria Studies
- Antibiotic Resistance in Bacteria
- Microbial Metabolic Engineering and Bioproduction
- Bacteriophages and microbial interactions
- Microbial Community Ecology and Physiology
- Lipid Membrane Structure and Behavior
- Enzyme Catalysis and Immobilization
- Plant and Biological Electrophysiology Studies
- Genomics and Phylogenetic Studies
- Microbial Inactivation Methods
- Legume Nitrogen Fixing Symbiosis
- Microbial Metabolism and Applications
- Legionella and Acanthamoeba research
- Biochemical and Structural Characterization
- Polysaccharides and Plant Cell Walls
- Infections and bacterial resistance
- Slime Mold and Myxomycetes Research
- Plant tissue culture and regeneration
- Photosynthetic Processes and Mechanisms
- Enzyme Production and Characterization
- Plant Pathogens and Fungal Diseases
Communication Bactérienne et Stratégie Anti-infectieuses
2023-2025
Université de Rouen Normandie
2013-2025
Normandie Université
2014-2025
Délégation Normandie
2019
Génétique Moléculaire Génomique Microbiologie
2008
Centre National de la Recherche Scientifique
2008
ABSTRACT Pseudomonas fluorescens MFE01 is an environmental bacterium characterized by hyperactive type 6 secretion system (T6SS) and a strong emission of volatile organic compounds (VOCs). In previous study, transposition mutant, 3H5, exhibited inactive T6SS altered VOC emission. the interruption trpE gene transposon was insufficient to explain these phenotypes. To determine actual impact this insertion, comparative transcriptomic analysis performed on two-component GacS/GacA, known...
Protein secretion systems are crucial mediators of bacterial interactions with other organisms. Among them, the type VI system (T6SS) is widespread in Gram-negative bacteria and appears to inject toxins into competitor and/or eukaryotic cells. Major human pathogens, such as Vibrio cholerae, Burkholderia Pseudomonas aeruginosa, express T6SSs. Bacteria prevent self-intoxication by their own T6SS producing immunity proteins, which interact cognate toxins. We describe here an environmental P....
Type VI secretion systems (T6SSs) are widespread in Gram-negative bacteria, including Pseudomonas. These macromolecular machineries inject toxins directly into prokaryotic or eukaryotic prey cells. Hcp proteins structural components of the extracellular part this machinery. We recently reported that MFE01, an avirulent strain Pseudomonas fluorescens, possesses at least two hcp genes, hcp1 and hcp2, encoding playing important roles interbacterial interactions. Indeed, P. fluorescens MFE01 can...
Abstract Background Pseudomonas fluorescens is a ubiquitous Gram-negative bacterium frequently encountered in hospitals as contaminant of injectable material and surfaces. This psychrotrophic bacterium, commonly described unable to grow at temperatures above 32°C, now considered non pathogenic. We studied recently identified clinical strain P. biovar I, MFN1032, which cause human lung infection can 37°C laboratory conditions. Results found that MFN1032 secreted extracellular factors with...
Pseudomonas fluorescens strain MFE01 secretes in abundance two Hcp proteins (haemolysin co-regulated proteins) Hcp1 and Hcp2, characteristic of a functional type 6 secretion system. Phenotypic studies have shown that has antibacterial activity against wide range competitor bacteria, including rhizobacteria clinically relevant bacteria. Mutagenesis the hcp2 gene abolishes or reduces, depending on target strain, activity. Hcp1, encoded by hcp1, may also be involved bacterial competition. We...
There is some debate about the potential survival of Pseudomonas fluorescens at temperatures above 37 °C and its consequences for infectious potential, owing to heterogeneity clinical strains. Seven strains growing or more were submitted polyphasic identification; 2 identified as mosselii 4 precisely characterized P. bv. I II. The binding indexes on glial cells compared with that a reference psychrotrophic strain, MF37 (bv. V). Clinical had similar adherence range than strain MF37....
Escherichia coli adherence to biotic and abiotic surfaces constitutes the first step of infection by promoting colonization biofilm formation. The aim this study was gain a better understanding relationship between E. different formation on surfaces. We isolated mutants defective in A549 pneumocyte cells adherence, fibronectin random transposition mutagenesis sequential passages over cell monolayers. Among 97 tested, 80 were decreased formation, 8 7 their fibronectin, 17 had no perturbations...
In the psychrotrophic bacterium Pseudomonas fluorescens, production of several enzymes that otherwise differ in their cell location, growth phase and inducibility appeared to be similarly regulated by temperature. order determine level this regulation, expression apo lip genes encoding two these enzymes, acidic phosphatase lipase, respectively, was studied at different temperatures. Both were optimally expressed 17.5°C, i.e., optimal temperature enzymes; however, low activity highest could...
The biocontrol agent Rhodococcus erythropolis disrupts virulence of plant and human Gram-negative pathogens by catabolizing their N-acyl-homoserine lactones. This quorum-quenching activity requires the expression qsd (quorum-sensing signal degradation) operon, which encodes lactonase QsdA fatty acyl-CoA ligase QsdC, involved in catabolism lactone ring acyl chain moieties signaling molecules, respectively. Here, we demonstrate regulation operon a TetR-like family repressor, QsdR. repression...
Type VI secretion systems (T6SSs) are contractile bacterial multiprotein nanomachines that enable the injection of toxic effectors into prey cells. The Pseudomonas fluorescens MFE01 strain has T6SS antibacterial activity and can immobilise competitive bacteria through T6SS. Hcp1 (hemolysin co-regulated protein 1), a constituent inner tube, is involved in such cell inhibition motility. Paradoxically, disruption hcp1 or tail tssC genes results loss mucoid motile phenotypes MFE01. Here, we...
Confocal laser-scanning microscopy was chosen to observe the colonization and damage caused by soft rot Pectobacterium atrosepticum protection mediated biocontrol agent Rhodococcus erythropolis. We developed dual-color reporter strains suited for monitoring quorum-sensing quorum-quenching activities leading maceration or biocontrol, respectively. A constitutively expressed cyan red fluorescent protein served as a cell tag plant colonization, while an inducible expression system based on...
Abstract Background MFN1032 is a clinical Pseudomonas fluorescens strain able to grow at 37°C. cells induce necrosis and apoptosis in rat glial this temperature. This displays secretion-mediated hemolytic activity involving phospholipase C cyclolipopeptides. Under laboratory conditions, not expressed tightly regulated subject phase variation. Results We found that cell-associated distinct from the secreted activity. Cell-associated hemolysis was 37°C only detected vitro mid log growth...
Biofilms are complex structures formed by a community of microbes adhering to surface and/or each other through the secretion an adhesive and protective matrix. The establishment these requires coordination action between microorganisms powerful communication systems such as quorum-sensing. Therefore, auxiliary bacteria capable interfering with means could be used prevent biofilm formation development. phytopathogen Rhizobium rhizogenes, which causes hairy root disease forms large biofilms...
Pseudomonas fluorescens is commonly considered a saprophytic rhizobacterium devoid of pathogenic potential. Nevertheless, the recurrent isolation strains from clinical human cases could indicate emergence novel originating rhizosphere reservoir, which be particularly resistant to immune system and treatment. The importance type three secretion systems (T3SSs) in related aeruginosa nosocomial species occurrence this plant-associated P. raise question whether isolates may also harbor T3SSs. In...
Abstract Background Pseudomonas aeruginosa , an opportunistic pathogen, is often encountered in chronic lung diseases such as cystic fibrosis or obstructive pneumonia, well acute settings like mechanical ventilation acquired pneumonia neutropenic patients. It a major cause of mortality and morbidity these diseases. In lungs, P. settles biofilm mode growth with the secretion exopolysaccharides which it encapsulated, enhancing its antibiotic resistance contributing to respiratory deficiency...
Cyclolipopeptides (CLPs) are biosurfactants produced by numerous Pseudomonas fluorescens strains. CLP production is known to be regulated at least the GacA/GacS two-component pathway, but full regulatory network yet largely unknown. In clinical strain MFN1032, abolished a mutation in phospholipase C gene () and not restored complementation. Their also subject phenotypic variation. We used modelling approach with Boolean networks, which takes into account all these observations concerning...