Many bacteria determine their population density using quorum sensing. The most intensively studied mechanism of quorum sensing utilizes proteins of the LuxI family to synthesize a signaling molecule of the acylhomoserine lactone (AHL) type, and a protein of the LuxR family to bind AHL and regulate transcription. Genes regulated by quorum sensing often encode functions that are most effective w...

Quorum sensing (QS) is a widespread process in bacteria used to coordinate gene expression with cell density, diffusion dynamics, and spatial distribution through the production of diffusible chemical signals. To date, most studies on QS have focused on model bacteria that are amenable to genetic manipulation and capable of high growth rates, but many environmentally important bacteria have bee...

Activated sludge used for wastewater treatment globally is composed of a high-density microbial community of great biotechnological significance. In this study the presence and purpose of quorum sensing via N-acylated-l-homoserine lactones (AHLs) in activated sludge was explored. The presence of N-heptanoyl-l-homoserine lactone in organic extracts of sludge was demonstrated along with activatio...

The waltzer (v) mouse mutant harbors a mutation in Cadherin 23 (Cdh23) and is a model for Usher syndrome type 1D, which is characterized by congenital deafness, vestibular dysfunction, and prepubertal onset of progressive retinitis pigmentosa. In mice, functionally null Cdh23 mutations affect stereociliary morphogenesis and the polarity of both cochlear and vestibular hair cells. In contrast, t...

The pathogenesis of Pseudomonas aeruginosa is associated with expression of virulence factors, many of which are controlled by two N:-acylhomoserine lactone (AHL)-based quorum-sensing systems. Escherichia coli strains equipped with a luxR-based monitor system expressing green fluorescent protein (GFP) in the presence of exogenous AHL molecules were used to detect the production of AHLs from P. ...

The paper discusses diierent approaches to formalize the representation of variables in Algebraic High-Level nets (AHL nets). We compare the approaches formally with regard to certain quality conditions a good AHL net formalization should satisfy. These quality conditions are (1) the cocompleteness of the underlying category of AHL nets and AHL net morphisms as this is the technical basis for t...

An enzyme hydrolyzing 4to g-carbon y-lactones has been purified 12to 15-fold from rat liver and from human plasma. In rat liver the enzyme is located in the microsomal fraction and may be solubilized by deoxycholate treatment and separated from microsomal B-esterase by ammonium sulfate fractionation. The effects of a series of inhibitors on y-lactonase, B-esterase purified from rat liver micros...

In Erwinia carotovora subspecies, N-acyl homoserine lactone (AHL) controls the expression of various traits, including extracellular enzyme/protein production and pathogenicity. We report here that E. carotovora subspecies possess two classes of quorum-sensing signaling systems defined by the nature of the major AHL analog produced as well as structural and functional characteristics of AHL syn...

Degradation of the quorum-sensing signal molecule N-acyl-L-homoserine lactone (AHL) in cocultures was verified with Bacillus cereus and Yersinia enterocolitica in culture medium and in pork extract. Results showed evidence of microbial interaction when the AHL-degrading bacterium and AHL-producing bacterium were cocultured in a food-simulating condition.