Pierre Cornelis

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The rhizobacterium Pseudomonas aeruginosa 7NSK2 produces secondary metabolites such as pyochelin (Pch), its precursor salicylic acid (SA), and the phenazine compound pyocyanin. Both 7NSK2 and mutant KMPCH (Pch-negative, SA-positive) induced resistance to Botrytis cinerea in wild-type but not in transgenic NahG tomato. SA-negative mutants of both strains(More)
Pseudomonads are ubiquitous Gram-negative γ proteobacteria known for their extreme versatility and adaptability. Some are plant pathogens (Pseudomonas syringae) which have to survive on the surface of leaves while others can colonize the rhizosphere or survive in soil (Pseudomonas fluorescens, Pseudomonas putida), and one species, Pseudomonas entomophila,(More)
Eighty-eight Pseudomonas aeruginosa isolates, most of them from the Collection of Bacterial Strains of the Institut Pasteur, Paris, were analysed for their pyoverdine-mediated iron incorporation system by different methods, including pyoverdine isoelectrofocusing analysis, pyoverdine-mediated growth stimulation, immunoblot detection of (ferri)pyoverdine(More)
In Pseudomonas aeruginosa, diverse virulence determinants and secondary metabolites are regulated via the action of a hierarchical quorum-sensing system which integrates two chemically distinct classes of signal molecules, the N-acylhomoserine lactones (AHLs) and the 4-quinolones (4Qs). Synthesis of the pseudomonas quinolone signal,(More)
Fourteen strains of Pseudomonas aeruginosa (P. aeruginosa ATCC 15692, P. aeruginosa ATCC 27853, and 12 clinical isolates) were checked for the production of pyoverdine and for pyoverdine-mediated iron uptake. Under iron restriction, two isolates produced undetectable amounts of pyoverdine, but all the other strains produced a compound with physicochemical(More)
Pseudomonas aeruginosa produces 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS), a quorum-sensing (QS) signal that regulates numerous virulence genes including those involved in iron scavenging. Biophysical analysis revealed that 2-alkyl-3-hydroxy-4-quinolones form complexes with iron(III) at physiological pH. The overall stability constant of(More)
Pyoverdines (PVDs) are complex siderophores produced by members of the fluorescent Pseudomonas. They comprise a dihydroxyquinoline fluorescent chromophore joined to a peptide of remarkably variable length and composition. In Pseudomonas aeruginosa, PVDs also function as signal molecules for the production of virulence factors. Genes responsible for the(More)
At present there are strong indications that Pseudomonas aeruginosa exhibits an epidemic population structure; clinical isolates are indistinguishable from environmental isolates, and they do not exhibit a specific (disease) habitat selection. However, some important issues, such as the worldwide emergence of highly transmissible P. aeruginosa clones among(More)
Pseudomonas putida GB-1-002 catalyzes the oxidation of Mn2+. Nucleotide sequence analysis of the transposon insertion site of a nonoxidizing mutant revealed a gene (designated cumA) encoding a protein homologous to multicopper oxidases. Addition of Cu2+ increased the Mn2+-oxidizing activity of the P. putida wild type by a factor of approximately 5. The(More)
Under conditions of iron limitation, Pseudomonas aeruginosa secretes a high-affinity siderophore pyoverdine to scavenge Fe(III) in the extracellular environment and shuttle it into the cell. Uptake of the pyoverdine-Fe(III) complex is mediated by a specific outer-membrane receptor protein, FpvA (ferripyoverdine receptor). Three P. aeruginosa siderovars can(More)