The resistance of Pseudomonas aeruginosa to antibiotics is multi factorial and complex. Whereas efflux pumps such as MexAB-OprM have been thought to predominate, here we show that a novel ATP Binding Cassette (ABC) transporter that... more
The resistance of Pseudomonas aeruginosa to antibiotics is multi factorial and complex. Whereas efflux pumps such as MexAB-OprM have been thought to predominate, here we show that a novel ATP Binding Cassette (ABC) transporter that mediates influx of carbenicillin from the periplasm to the cytoplasm and away from its cell wall target plays an important role in the resistance of P. aeruginosa to this antibiotic. Treatment of P. aeruginosa with verapamil, an inhibitor of ABC transporters in eukaryotic cells, increases its sensitivity to carbenicillin. Using amino acid sequence homology with known verapamil protein targets as a probe, we determined that the PA1113 gene product, an ABC transporter, mediates carbenicillin uptake into the bacterial cytoplasm. Docking and pharmacological analyses showed that verapamil and carbenicillin compete for the same site on the PA1113 gene protein, explaining the inhibitory effect of verapamil on carbenicillin uptake, and furthermore suggest that th...
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THE FRANCO-BRAZILIAN NETWORK ON NATURAL PRODUCTS (FB2NP): A NEW NETWORK PROMOTING COOPERATION AND EXCHANGES IN NATURAL PRODUCTS RESEARCH
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Published Ahead of Print 8 June 2012. 2012, 194(16):4301. DOI: 10.1128/JB.00509-12. J. Bacteriol. and Sylvie Chevalier Feuilloley, Nicole Orange, R. E. W. Hancock, Alain Dufour Manjeet Bains, Olivier Maillot, Julien Vieillard, Marc G. J.... more
Published Ahead of Print 8 June 2012. 2012, 194(16):4301. DOI: 10.1128/JB.00509-12. J. Bacteriol. and Sylvie Chevalier Feuilloley, Nicole Orange, R. E. W. Hancock, Alain Dufour Manjeet Bains, Olivier Maillot, Julien Vieillard, Marc G. J. Emeline Bouffartigues, Gwendoline Gicquel, Alexis Bazire, Sucrose Induced Mainly on the SigX Sigma Factor and Is Pseudomonas aeruginosa Is Dependent Gene of oprF Transcription of the
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Cichorium intybus L. (Asteraceae) is an important industrial crop, as well as a medicinal plant which produces some bioactive compounds implicated in various biological effects with potential applications in human health. Particularly,... more
Cichorium intybus L. (Asteraceae) is an important industrial crop, as well as a medicinal plant which produces some bioactive compounds implicated in various biological effects with potential applications in human health. Particularly, roots produce hydroxycinnamic acids like 5-caffeoyquinic acid and 3,5-dicaffeoylquinic acid (di-CQA). The present investigation relates to the use of methyl jasmonate for enhancing phenolic compounds accumulation and production in hairy root cultures of C. intybus. Elicitated hairy root growth rate increased 13.3 times compared with the initial inoculum in a period of 14 days and di-CQA production represented about 12% of DW. The elicitation has also promoted the production of tricaffeoylquinic acid never described in the chicory roots and identified as 3,4,5-tricaffeoyquinic acid by means of nuclear magnetic resonance. Our study confirmed the strong anti-oxidant effect of di-CQA. Our results also confirmed globally a selectivity of action of di-CQA a...
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Since antiquity, the ubiquitous lactic acid bacteria (LAB) Enterococci, which are just as predominant in both human and animal intestinal commensal flora, have been used (and still are) as probiotics in food and feed production. Their... more
Since antiquity, the ubiquitous lactic acid bacteria (LAB) Enterococci, which are just as predominant in both human and animal intestinal commensal flora, have been used (and still are) as probiotics in food and feed production. Their qualities encounter several hurdles, particularly in terms of the array of virulence determinants, reflecting a notorious reputation that nearly prevents their use as probiotics. Additionally, representatives of the Enterococcus spp. genus showed intrinsic resistance to several antimicrobial agents, and flexibility to acquire resistance determinants encoded on a broad array of conjugative plasmids, transposons, and bacteriophages. The presence of such pathogenic aspects among some species represents a critical barrier compromising their use as probiotics in food. Thus, the genus neither has Generally Recognized as Safe (GRAS) status nor has it been included in the Qualified Presumption of Safety (QPS) list implying drastic legislation towards these mic...
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Pseudomonas aeruginosa PAO1 has an integrated Pf4 prophage in its genome, encoding a relatively well-characterized filamentous phage, which contributes to the bacterial biofilm organization and maturation. Pf4 variants are considered as... more
Pseudomonas aeruginosa PAO1 has an integrated Pf4 prophage in its genome, encoding a relatively well-characterized filamentous phage, which contributes to the bacterial biofilm organization and maturation. Pf4 variants are considered as superinfectives when they can re-infect and kill the prophage-carrying host. Herein, the response of P. aeruginosa H103 to Pf4 variant infection was investigated. This phage variant caused partial lysis of the bacterial population and modulated H103 physiology. We show by confocal laser scanning microscopy that a Pf4 variant-infection altered P. aeruginosa H103 biofilm architecture either in static or dynamic conditions. Interestingly, in the latter condition, numerous cells displayed a filamentous morphology, suggesting a link between this phenotype and flow-related forces. In addition, Pf4 variant-infection resulted in cell envelope stress response, mostly mediated by the AlgU and SigX extracytoplasmic function sigma factors (ECFσ). AlgU and SigX i...
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Pseudomonas aeruginosa is an important multidrug-resistant human pathogen by dint of its high intrinsic, acquired, and adaptive resistance mechanisms, causing great concern for immune-compromised individuals and public health.... more
Pseudomonas aeruginosa is an important multidrug-resistant human pathogen by dint of its high intrinsic, acquired, and adaptive resistance mechanisms, causing great concern for immune-compromised individuals and public health. Additionally, P. aeruginosa resilience lies in the production of a myriad of virulence factors, which are known to be tightly regulated by the quorum sensing (QS) system. Anti-virulence therapy has been adopted as an innovative alternative approach to circumvent bacterial antibiotic resistance. Since plants are known repositories of natural phytochemicals, herein, we explored the anti-virulence potential of Azorella atacamensis, a medicinal plant from the Taira Atacama community (Calama, Chile), against P. aeruginosa. Interestingly, A. atacamensis extract (AaE) conferred a significant protection for human lung cells and Caenorhabditis elegans nematodes towards P. aeruginosa pathogenicity. The production of key virulence factors was decreased upon AaE exposure ...
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ABSTRACTPseudomonas aeruginosa is capable to deploy a collection of virulence factors that are not only essential for host infection and persistence, but also to escape from the host immune system and to become more resistant to drug... more
ABSTRACTPseudomonas aeruginosa is capable to deploy a collection of virulence factors that are not only essential for host infection and persistence, but also to escape from the host immune system and to become more resistant to drug therapies. Thus, developing anti-virulence agents that may directly counteract with specific virulence factors or disturb higher regulatory pathways controlling the production of virulence armories are urgently needed. In this regard, this study reports that Pistacia lentiscus L. fruit cyclohexane extract (PLFE1) thwarts P. aeruginosa virulence by targeting mainly the pyocyanin pigment production by interfering with 4-hydroxy-2-alkylquinolines molecules production. Importantly, the anti-virulence activity of PLFE1 appears to be associated with membrane homeostasis alteration through the modulation of SigX, an extracytoplasmic function sigma factor involved in cell wall stress response. A thorough chemical analysis of PLFE1 allowed us to identify the gin...
Research Interests: Physiology, Gene expression, Humans, Mice, Animals, and 15 moreMale, Clinical Sciences, Cattle, Middle Aged, Human Genome, mRna expression levels, Adult, Amino Acid Sequence, Base Sequence, Protein Binding, Seminal Plasma, Nucleic Acid, Molecular Sequence Data, cDNA cloning, and Paediatrics and reproductive medicine
Pseudomonas baetica strain a390T is the type strain of this recently described species and here we present its high-contiguity draft genome. To celebrate the 16th International Conference on Pseudomonas, the genome of P. baetica strain... more
Pseudomonas baetica strain a390T is the type strain of this recently described species and here we present its high-contiguity draft genome. To celebrate the 16th International Conference on Pseudomonas, the genome of P. baetica strain a390T was sequenced using a unique combination of Ion Torrent semiconductor and Oxford Nanopore methods as part of a collaborative community-led project. The use of high quality Ion Torrent sequences with long Nanopore reads gave rapid, high contiguity and quality, 16 contig genome sequence. Whole genome phylogenetic analysis places P. baetica within the Pseudomonas koreensis clade of the Pseudomonas fluorescens group. Comparison of the main genomic features of P. baetica with a variety of other Pseudomonas spp. suggests that it is a highly adaptable organism, typical of the genus. This strain was originally isolated from the liver of a diseased wedge sole fish and genotypic and phenotypic analyses show that it is tolerant to osmotic stress and to oxy...
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Dans cette these sont presentes les travaux visant a ameliorer les conditions de detection de deux closterovirus de la vigne, le virus a (gva) et le virus 1 associe a l'enroulement de la vigne (glrav 1), a demontrer le role du gva... more
Dans cette these sont presentes les travaux visant a ameliorer les conditions de detection de deux closterovirus de la vigne, le virus a (gva) et le virus 1 associe a l'enroulement de la vigne (glrav 1), a demontrer le role du gva dans l'etiologie d'un syndrome de cannelures du tronc, le kober stem grooving (ksg), et a voir des relations entre la multiplication des virus et le niveau d'expression des symptomes de cannelures. Une technique de tres haute sensibilite, basee sur l'amplification genique (pcr) d'un fragment de genome du gva precedee d'une etape d'immunocapture du virus, a ete adaptee a la detection du virus dans la vigne. Pour le glrav 1, la sequence primaire de l'extremite n-terminale de sa coque proteique a ete determinee pour la production d'amorces specifiques pour la synthese et le clonage d'adn complementaire au rna viral, necessaires a sa detection par pcr. La recherche par pcr du gva dans des vignes malades et/ou traitees par thermotherapie a demontre l'etroite correlation entre la presence du gva et le ksg ; l'inoculation du gva a la vigne par heterogreffage in vitro sur n. Benthamiana infecte a entraine le developpement de symptomes sur le porte-greffe sensible kober 5bb, ce qui a confirme l'implication du gva dans l'etiologie du ksg et a montre que le ksg restait latent sans greffage. La detection in situ du gva par immunomarquage de coupes de tiges de kober 5bb infecte n'a revele aucune difference quantitative dans sa multiplication avant et apres greffage, mais que la surinfection par le glrav 1, accentue la severite des symptomes de ksg
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Research Interests: Mass Spectrometry, Humans, Female, Male, Young Adult, and 7 moreSkin, Skin Diseases, Aged, Middle Aged, Adult, Biota, and Dysbiosis
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Research Interests: Microbiology, Medical Microbiology, Biology, Capillary electrophoresis, Apoptosis, and 15 moreMedicine, Adhesion, Mobility, Animals, Cell Death, Bacteria, Glial Cell, High Temperature, Apoptose, Cell nucleus, Lipopolysaccharides, Low Temperature, Lactate dehydrogenase, Bacterial Adhesion, and Molecular Structure
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A liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method using reversed-phase chromatography was developed for the analysis of phospholipids from bacterial extracts of a wild-type strain of... more
A liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method using reversed-phase chromatography was developed for the analysis of phospholipids from bacterial extracts of a wild-type strain of Escherichia coli. Product ion mass spectra from [M--H](-) precursor ions allowed an identification of individual phospholipid species that includes both fatty acid composition and fatty acyl location on the glycerol backbone using diagnostic product ions. Thus, complete assignment, including sn-1/sn-2 fatty acyl position, was achieved for this strain of E. coli. In addition, the phospholipids were quantified relative to one another using an internal standard method.
Research Interests: Earth Sciences, Chemistry, Membranes, Phospholipids, Medicine, and 14 moreBiological Sciences, Lipids, Fatty acids, Escherichia coli, Tandem Mass Spectrometry, High Performance Liquid Chromatography, High Pressure Liquid Chromatography, CHEMICAL SCIENCES, Liquid Chromatography / Electrospray Ionization Mass Spectrometry, Liquid Chromatography, Acylation, Culture Media, Reference standards, and Electrospray Ionization
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Erwinia carotovora subsp. atroseptica is responsible for potato blackleg disease in the field and tuber soft rot during crop storage. The process leading to the disease occurs in two phases: a primary invasion step followed by a... more
Erwinia carotovora subsp. atroseptica is responsible for potato blackleg disease in the field and tuber soft rot during crop storage. The process leading to the disease occurs in two phases: a primary invasion step followed by a maceration step. Bacteria-to-bacteria communication is associated with a quorum-sensing (QS) process based on the production of N-acylhomoserine lactones (HSL). The role of HSL throughout plant infection was analyzed. To this purpose, HSL produced by a specific E. carotovora subsp. atroseptica wild-type strain, which was particularly virulent on potato, were identified. A derivative of this strain that expressed an HSL lactonase gene and produced low amounts of HSL was generated. The comparison of these strains allowed the evaluation of the role of HSL and QS in disease establishment and development. Bacterial growth and motility; activity of proteins secreted by type I, II, and III systems; and hypersensitive and maceration reactions were evaluated. Results...
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Enterococcus faecalisis a ubiquitous bacterium that is capable of surviving in a broad range of natural environments, including the human host, as either a natural commensal or an opportunistic pathogen involved in severe... more
Enterococcus faecalisis a ubiquitous bacterium that is capable of surviving in a broad range of natural environments, including the human host, as either a natural commensal or an opportunistic pathogen involved in severe hospital-acquired infections. How such opportunistic pathogens cause fatal infections is largely unknown but it is likely that they are equipped with sophisticated systems to perceive external signals and interact with eukaryotic cells. Accordingly, being partially exposed at the cell exterior, some surface-associated proteins are involved in several steps of the infection process. Among them are lipoproteins, representing about 25 % of the surface-associated proteins, which could play a major role in bacterial virulence processes. This review focuses on the identification of 90 lipoprotein-encoding genes in the genome of theE. faecalisV583 clinical strain and their putative roles, and provides a transcriptional comparison of microarray data performed in environmen...