Pseudomonas aeruginosa uses quorum sensing (QS) to regulate the production of public goods such as the secreted protease elastase. P. aeruginosa requires the LasI-LasR QS circuit to induce elastase and enable growth on casein as the sole carbon and energy source. The LasI-LasR system also induces a second QS circuit, the RhlI-RhlR system. During growth on casein, LasR-mutant social cheaters eme...

Quorum sensing (QS) has been recognized as a general phenomenon in microorganisms and plays an important role in many pathogenic bacteria. In this report, we used the Agrobacterium tumefaciens biosensor strain NT1 to rapidly screen for autoinducer-quenching inhibitors from bacteria. After initial screening 5389 isolates obtained from land and beach soil, 53 putative positive strains were identi...

Many members of the LuxR family of quorum sensing (QS) transcriptional activators, including LasR of Pseudomonas aeruginosa, are believed to require appropriate acyl-homoserine lactone (acyl-HSL) ligands to fold into an active conformation. The failure to purify ligand-free LuxR homologues in nonaggregated form at the high concentrations required for their structural characterization has limite...

T identification of drug targets for a given human disease, whether it is mainly environmental or genetic in origin, rests on an understanding of the molecular chain of events that unfold in the disease process. Anatomic pathology, biochemistry, cellular physiology, and pharmacology constitute the main traditional approaches towards identifying potential therapeutic targets. Genetic approaches,...

Introduction. Even in patients with well-controlled arterial hypertension (AH) and without significant comorbidities, left ventricular (LV) atrial (LA) strain abnormalities may sometimes be found speckle-tracking echocardiography. Therefore, the aim of this study was to investigate correlation between LA LV diastolic systolic function a group treated, AH. Material methods. contractile, conduit,...

This study was based on the hypothesis that biofilms of the opportunistic pathogen Pseudomonas aeruginosa are successfully adapted to situations of protozoan grazing. We tested P. aeruginosa wild type and strains that were genetically altered, in structural and regulatory features of biofilm development, in response to the common surface-feeding flagellate Rhynchomonas nasuta. Early biofilms of...

Pseudomonas aeruginosa uses the two major quorum-sensing (QS) regulatory systems las and rhl to modulate the expression of many of its virulence factors. The las system is considered to stand at the top of the QS hierarchy. However, some virulence factors such as pyocyanin have been reported to still be produced in lasR mutants under certain conditions. Interestingly, such mutants arise spontan...

The bacterium Pseudomonas aeruginosa is an opportunistic human pathogen that uses a quorum sensing signal cascade to activate expression of dozens of genes when sufficient population densities have been reached. Quorum sensing controls production of several key virulence factors, including secreted proteases such as elastase. Cooperating groups of bacteria growing on protein are susceptible to ...

Bacterial growth and virulence often depends upon the cooperative release of extracellular factors excreted in response to quorum sensing (QS). We carried out an in vivo selection experiment in mice to examine how QS evolves in response to variation in relatedness (strain diversity), and the consequences for virulence. We started our experiment with two bacterial strains: a wild-type that both ...

Quorum sensing (QS) is a process of cell-cell communication in bacteria by the use of signalling molecules that bind to the receptor protein and directly or indirectly affect transcription and translation. QS proteins may be used as a drug target for the inhibition of signalling pathway to control bacterial cell population. In present study the QS protein LasR of Pseudomonas aeruginosa was used...