A5079917358- Bacterial biofilms and quorum sensing
- Antibiotic Resistance in Bacteria
- Bacterial Genetics and Biotechnology
- Microbial bioremediation and biosurfactants
- Vibrio bacteria research studies
- Cystic Fibrosis Research Advances
- Plant Pathogenic Bacteria Studies
- Legume Nitrogen Fixing Symbiosis
- Microbial Community Ecology and Physiology
- Carbohydrate Chemistry and Synthesis
- Bacteriophages and microbial interactions
- Plant-Microbe Interactions and Immunity
- Water Treatment and Disinfection
- Antimicrobial Peptides and Activities
- Insect symbiosis and bacterial influences
- Environmental Chemistry and Analysis
- Enzyme Catalysis and Immobilization
- Antifungal resistance and susceptibility
- Legionella and Acanthamoeba research
- Burkholderia infections and melioidosis
- Microbial Metabolic Engineering and Bioproduction
- biodegradable polymer synthesis and properties
- Toxic Organic Pollutants Impact
- Glycosylation and Glycoproteins Research
- Genomics and Phylogenetic Studies
Institut National de la Recherche Scientifique
2016-2025
McGill University
2022
Armand Frappier Museum
2011-2020
University of Nottingham
2016
Polytechnique Montréal
2000-2014
Weatherford College
2013
Harvard University
2003-2006
Massachusetts General Hospital
2003-2006
Burn Institute
2006
Stanford University
2004
Bacterial communities use "quorum sensing" (QS) to coordinate their population behavior through the action of extracellular signal molecules, such as N-acyl-l-homoserine lactones (AHLs). The versatile and ubiquitous opportunistic pathogen Pseudomonas aeruginosa is a well-studied model for AHL-mediated QS. This species also produces an intercellular distinct from AHLs, 3,4-dihydroxy-2-heptylquinoline (PQS), which belongs family poorly characterized 4-hydroxy-2-alkylquinolines (HAQs)...
Abstract Background Pseudomonas aeruginosa is a ubiquitous environmental bacterium and an important opportunistic human pathogen. Generally, the acquisition of genes in form pathogenicity islands distinguishes pathogenic isolates from nonpathogens. We therefore sequenced highly virulent strain P. , PA14, compared it with previously (and less pathogenic) strain, PAO1, to identify novel virulence genes. Results The PA14 PAO1 genomes are remarkably similar, although has slightly larger genome...
Pseudomonas aeruginosa produces extracellular glycolipids composed of L-rhamnose and 3-hydroxyalkanoic acid called rhamnolipids. Although these compounds are usually regarded as biosurfactants or haemolysins, their exact physiological function is not well understood. Rhamnolipids synthesized by a rhamnosyltransferase, encoded the rhlAB operon, which catalyses transfer TDP-L-rhamnose to 3-(3-hydroxyalkanoyloxy)alkanoic (HAA) moieties various lengths. RhlB catalytic protein...
Pseudomonas aeruginosa is a ubiquitous environmental bacterium capable of forming biofilms on surfaces as survival strategy. It exhibits large variety competition/virulence factors, such three types motilities: flagellum-mediated swimming, swarming, and type IV pilus-mediated twitching. A strategy frequently used by bacteria to survive changing conditions create phenotypically heterogeneous population mechanism called phase variation. In this report, we describe the characterization...
Opportunistic infections are often polymicrobial. Two of the most important bacterial opportunistic pathogens humans, Pseudomonas aeruginosa and Staphylococcus aureus, frequently coisolated from catheters, endotracheal tubes, skin, eyes, respiratory tract, including airways people with cystic fibrosis (CF). Here, we show that suppression S. aureus respiration by a P. exoproduct, 4-hydroxy-2-heptylquinoline-N-oxide (HQNO), protects during coculture killing commonly used aminoglycoside...
Summary The transcriptional regulator MvfR is required for full Pseudomonas aeruginosa virulence, the function of multiple quorum sensing (QS)‐regulated virulence factors and synthesis 4‐hydroxy‐2‐alkylquinolines (HAQs), including quinolone signal (PQS). Here we investigate role in QS circuitry P. pathogenesis. We demonstrate using a combination biochemical molecular approaches, transcription profiling, that involved regulation QS‐controlled genes without altering expression lasRI / rhlRI or...
The ubiquitous bacterium Pseudomonas aeruginosa is the quintessential opportunistic pathogen. Certain isolates infect a broad range of host organisms, from plants to humans. pathogenic promiscuity particular variants may reflect an increased virulence gene repertoire beyond core P. genome. We have identified and characterized two pathogenicity islands (PAPI-1 PAPI-2) in genome PA14, highly virulent clinical isolate. 108-kb PAPI-1 11-kb PAPI-2, which are absent less reference strain PAO1,...
Pseudomonas aeruginosa is an opportunistic human pathogen capable of forming a biofilm under physiological conditions that contributes to its persistence despite long-term treatment with antibiotics. Here, we report pathogenic P. strains PAO1 and PA14 are infecting the roots Arabidopsis sweet basil (Ocimum basilicum), in vitro soil, causing plant mortality 7 d postinoculation. Before mortality, colonize form as observed by scanning electron microscopy, phase contrast confocal laser...
Summary The opportunistic pathogen Pseudomonas aeruginosa undergoes genetic change during chronic airway infection of cystic fibrosis (CF) patients. One common is a mutation inactivating lasR , which encodes transcriptional regulator that responds to homoserine lactone signal activate expression acute virulence factors. Colonies mutants visibly accumulated the iridescent intercellular 4‐hydroxy‐2‐heptylquinoline. Using this colony phenotype, we identified P. emerged in CF patient early...
Pseudomonas aeruginosa uses the two major quorum-sensing (QS) regulatory systems las and rhl to modulate expression of many its virulence factors. The system is considered stand at top QS hierarchy. However, some factors such as pyocyanin have been reported still be produced in lasR mutants under certain conditions. Interestingly, arise spontaneously various conditions, including airways cystic fibrosis patients. Using transcriptional lacZ reporters, LC/MS quantification phenotypic assays,...
Chronic Pseudomonas aeruginosa infections cause significant morbidity in patients with cystic fibrosis (CF). Over years to decades, P. adapts genetically as it establishes chronic lung infections. Nonsynonymous mutations lasR, the quorum-sensing (QS) master regulator, are common CF. In laboratory strains of aeruginosa, LasR activates transcription dozens genes, including that for another QS RhlR. Despite frequency which lasR coding variants have been reported occur CF isolates, little is...
The capacity of polycyclic aromatic hydrocarbon (PAH)-utilizing bacteria to produce biosurfactants was investigated. Twenty-three isolated from a soil contaminated with petroleum wastes were able form clearing zones on mineral salt agar plates sprayed solutions PAHs. Naphthalene and phenanthrene utilized as sole substrates. Biosurfactant production detected by surface tension lowering emulsifying activities 10 these strains grown in an iron-limited medium supplemented high concentrations...
Summary MvfR (PqsR), a Pseudomonas aeruginosa LysR‐type transcriptional regulator, plays critical role in the virulence of this pathogen. modulates expression multiple quorum sensing (QS)‐regulated factors; and phnAB pqsA‐E genes that encode functions mediating 4‐hydroxy‐2‐alkylquinolines (HAQs) signalling compounds biosynthesis, including 3,4‐dihydroxy‐2‐heptylquinoline (PQS) its precursor 4‐hydroxy‐2‐heptylquinoline (HHQ). PQS enhances vitro DNA‐binding affinity to promoter, suggest it...
The opportunistic pathogen Pseudomonas aeruginosa produces a large array of 4-hydroxy-2-alkylquinolines (HAQs). These compounds were analyzed by LC/MS, using positive electrospray ionization, in the culture supernatant strain PA14. Fifty-six HAQs and related detected their [M+H]+ ions further collision induced dissociation (CID). grouped into five different series based on presence an hydrogen or hydroxyl group at 3 position, N-oxide place quinoline nitrogen, unsaturation alkyl side chain....
Swarming is a type of social motility allowing the migration highly differentiated bacterial cells. shares many similarities with biofilm communities, which are notable for their high resistance to antimicrobial agents. We investigate here if swarming behaviour could also be associated widespread resistant phenotype. Challenged 13 antibiotics from various classes, swarm cells Pseudomonas aeruginosa, Escherichia coli, Serratia marcescens, Burkholderia thailandensis and Bacillus subtilis...
Long-term antibiotic use generates pan-resistant super pathogens. Anti-infective compounds that selectively disrupt virulence pathways without affecting cell viability may be used to efficiently combat infections caused by these A candidate target pathway is quorum sensing (QS), which many bacterial pathogens coordinately regulate determinants. The Pseudomonas aeruginosa MvfR-dependent QS regulatory controls the expression of key genes; and activated via extracellular signals...
Abstract Background Rhamnolipids are surface active molecules composed of rhamnose and β-hydroxydecanoic acid. These biosurfactants produced mainly by Pseudomonas aeruginosa have been thoroughly investigated since their early discovery. Recently, they attracted renewed attention because involvement in various multicellular behaviors. Despite this high interest, only very few studies focused on the production rhamnolipids Burkholderia species. Results Orthologs rhlA , rhlB rhlC which...
Summary Pseudomonas aeruginosa presents three types of motilities: swimming, twitching and swarming. The latter is characterized by rapid coordinated group movement over a semisolid surface resulting from morphological differentiation intercellular interactions. A striking feature P. swarming motility the formation migrating tendrils producing colonies with complex fractal‐like patterns. Previous studies have shown that normal intimately related to production extracellular surface‐active...
Background. Cystic fibrosis (CF) lung disease is associated with diverse bacteria chronically infecting the airways. Slow-growing, antibiotic-resistant mutants of Staphylococcus aureus known as small-colony variants (SCVs) have been isolated from respiratory secretions European adults and children CF using specific but infrequently used culture techniques. SCVs can be selected either by exposure to antibiotics or growth another pathogen, Pseudomonas aeruginosa. We sought determine...
Most bacteria in nature live surface-associated communities rather than planktonic populations. Nonetheless, how environments shape bacterial evolutionary adaptation remains poorly understood. Here, we show that subjecting Pseudomonas aeruginosa to repeated rounds of swarming, a collective form surface migration, drives remarkable parallel evolution toward hyperswarmer phenotype. In all independently evolved hyperswarmers, the reproducible hyperswarming phenotype is caused by point mutations...
The properties and applications of rhamnolipid surfactants produced by Pseudomonas aeruginosa L2-1 from cassava wastewater added with waste cooking oil (CWO) as low-cost substrate, were investigated compared the commercial mixture JBR599 (Jeneil Biosurfactant Co., Saukville, USA). rhamnolipids strain characterized high performance liquid chromatography–mass spectrometry. Sixteen different congeners detected, Rha-C10-C10 Rha-Rha-C10-C10 being most abundant. CWO showed similar or better...