The expression of virulence determinants in Pseudomonas aeruginosa is coordinately regulated in response to both the social environment--commonly referred to as quorum sensing--and to environmental cues. In this study we have dissected the various independent regulation levels for pyocyanin production, which is influenced by the homoserine lactone- and Pseudomonas quinolone signal (PQS)-mediate...

Pseudomonas aeruginosa is a ubiquitous environmental bacterium capable of forming biofilms on surfaces as a survival strategy. It exhibits a large variety of competition/virulence factors, such as three types of motilities: flagellum-mediated swimming, flagellum-mediated swarming, and type IV pilus-mediated twitching. A strategy frequently used by bacteria to survive changing environmental cond...

Pseudomonas aeruginosa culture filtrates varied in their ability to slow human ciliary beat frequency (7-71%). This activity did not correlate with known virulence factors. However, a close correlation (r = 0.97) existed between ciliary slowing and pigment content. In a prolonged culture, the increase in activity correlated (r = 0.94) with pigment accumulation. Gel filtration of lyophilized fil...

In Pseudomonas aeruginosa, chemical deconvolution of the pyocyanin voltammetric signal allows its expression to be observed simultaneously with the quorum sensing molecule Pseudomonas quinolone signal (PQS). Such analysis has revealed that PQS might protect pyocyanin from self-oxidation, but also exert a pro-oxidative effect on pyocyanin under oxidative conditions to produce additional redox me...

Pyocyanin is a small molecule produced by Pseudomonas aeruginosa that plays a crucial role in the pathogenesis of infections by this notorious opportunistic pathogen. The inhibition of pyocyanin production has been identified as an attractive antivirulence strategy for the treatment of P. aeruginosa infections. Herein, we report the discovery of an inhibitor of pyocyanin production in cultures ...

Bacterial persister cells constitute a small portion of a culture which is tolerant to killing by lethal doses of bactericidal antibiotics. These phenotypic variants are formed in numerous bacterial species, including those with clinical relevance like the opportunistic pathogen Pseudomonas aeruginosa. Although persisters are believed to contribute to difficulties in the treatment of many infec...

INTRODUCTION The emergence of carbapenem resistance mechanisms in Pseudomonas aeruginosa has been outstanding due to the wide spectrum of antimicrobial degradation of these bacteria, reducing of therapeutic options. METHODS Sixty-one clinical strains of P. aeruginosa isolated from five public hospitals in Recife, Pernambuco, Brazil, were examined between 2006 and 2010, aiming of evaluating th...

Preparation of the toxin pyocyanin from the bacterium Pseudomonas aeruginosa is an exacting procedure. Pyocyanin is expensive to commercially purchase. The sellers do not give out the extraction procedure. Classically, pyocyanin preparation involves complicated multi-step P. aeruginosa culturing and solvent transfer extractions. The chemical synthesis first used (1979) has not been adequately d...

Lon protease, a member of the ATP-dependent protease family, regulates numerous cellular systems by degrading specific substrates. Here, we demonstrate that Lon is involved in the regulation of quorum-sensing (QS) signaling systems in Pseudomonas aeruginosa, an opportunistic human pathogen. The organism has two acyl-homoserine lactone (HSL)-mediated QS systems, LasR/LasI and RhlR/RhlI. Many rep...

A biomolecule namely pyocyanin was isolated from Pseudomonas aeruginosa (BTRY1). It was confirmed by UV-Vis spectrum with absorption maxima at 270 nm and was further characterized using Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR). Spectroscopy analyses showed the presence of relevant bonds in their respective structures. Although pyocyanin had antihemolytic, antioxida...