Vfr or CyaB promote the expression of the pore-forming toxin operon in ATCC 9027 without increasing its virulence in mice.

is a wide-spread γ-proteobacterium that produces the biosurfactant rhamnolipid that has a great commercial value due to excellent properties of low toxicity and high biodegradability. However, this bacterium is an opportunist pathogen that constitutes an important health hazard due to its production of virulence-associated traits and its high antibiotic resistance. Thus, it is highly desirable to have a non-virulent strain for rhamnolipid production.

PqsR-independent quorum-sensing response of Pseudomonas aeruginosa ATCC 9027 outlier-strain reveals new insights on the PqsE effect on RhlR activity.

Pseudomonas aeruginosa is a ubiquitous environmental bacterium and an opportunistic pathogen that represents an important health hazard. The quorum-sensing response regulates the expression of several virulence factors and involves three regulons: Las, Rhl, and Pqs. The P.

Tracking the genome of four isolates that have a defective Las quorum-sensing system, but are still virulent.

In this work we analysed the whole genome extended multilocus sequence typing (wgMLST) of four strains that are characterized by being virulent despite having a defective Las quorum-sensing (QS) system, and compare them with the wgMLST of the PAO1 and PA14 type strains. This comparison was done to determine whether there was a genomic characteristic that was common to the strains with an atypical QS response. The analysed strains include two environmental isolates (ID 4365 isolated from the Indian Ocean, and M66 isolated from the Churince water system in Cuatro Ciénegas Coahuila, México), one veterinary isolate (strain 148 isolated from the stomach of a dolphin) and a clinical strain (INP43 that is a cystic fibrosis pediatric isolate).

The outlier Pseudomonas aeruginosa strain ATCC 9027 harbors a defective LasR quorum-sensing transcriptional regulator.

Pseudomonas aeruginosa infections represent an important health problem that has been recognized by the World Health Organization as a research priority. A complex regulatory network called the quorum sensing (QS) regulates several P. aeruginosa virulence-related traits, including production of elastase, rhamnolipids and pyocyanin.

The third quorum-sensing system of : quinolone signal and the enigmatic PqsE protein.

is an opportunistic pathogen that produces several virulence factors such as lectin A, pyocyanin, elastase and rhamnolipids. These compounds are controlled transcriptionally by three quorum-sensing circuits, two based on the synthesis and detection of -acyl-homoserine-lactone termed the Las and Rhl system and a third system named the quinolone signal (PQS) system, which is responsible for generating 2-alkyl-4(1 h)-quinolones (AQs). The transcriptional regulator called PqsR binds to the promoter of in the presence of PQS or HHQ creating a positive feedback-loop.

Partial characterization of a biosurfactant extracted from Pseudomonas sp. B0406 that enhances the solubility of pesticides.

Biodegradation of some organochlorine and organophosphate pesticides is difficult because of their low solubility in water and, therefore, their low bioavailability. To overcome the hydrophobicity problem and the limited pesticide availability, biosurfactants play a major role. In this study, we evaluated the effect of an extract from Pseudomonas sp.