Background: N-Acyl homoserine lactone (AHL) is found to be the main component of quorum sensing (QS) in Gram-negative bacteria and plays an important role in biofilm formation. Little information is available regarding the role of AHL in biofilm formation in Escherichia coli (E. coli). The purpose of this investigation was to biochemically detect and characterize AHL activity in biofilm-forming...

An investigation of name-bearing types and other relevant type specimens of twelve nominal Leptopelis taxa described from or distributed in the Eastern Arc Mountains in East Africa was carried out. Our aim was to clarify their status and where necessary revise respective nomina. We suggest several nomenclatural and taxonomic actions: 1) Leptopelis barbouri Ahl, 1929 is transferred to the synony...

Algebraic High-Level (AHL) nets are a well-known modelling technique based on Petri nets with algebraic data types, which allows to model the communication structure and the data flow within one modelling framework. Transformations of AHL-nets – inspired by the theory of graph transformations – allow in addition to modify the communication structure. Moreover, high-level processes of AHL-nets c...

Many Proteobacteria govern responses to changes in cell density by using acyl-homoserine lactone (AHL) quorum-sensing (QS) signaling. Similar to the LuxI-LuxR system described in Vibrio fischeri, a minimal AHL QS circuit comprises a pair of genes, a luxI-type synthase gene encoding an enzyme that synthesizes an AHL and a luxR-type AHL-responsive transcription regulator gene. In most bacteria th...

N-acylhomoserine lactone (AHL)-based quorum sensing (QS) is important for the regulation of proteobacterial virulence determinants. Thus, the inhibition of AHL synthases offers non-antibiotics-based therapeutic potentials against QS-mediated bacterial infections. In this work, functional AHL synthases of Pseudomonas aeruginosa LasI and RhlI were heterologously expressed in an AHL-negative Esche...

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...

Many Gram-positive and Gram-negative bacteria communicate using small diffusible signal molecules called autoinducers. This process, known as quorum sensing (QS), links cell density to the expression of genes as diverse as those associated with virulence factors production of plant and animal pathogens, bioluminescence, antibiotic production, sporulation or biofilm formation. In Gram-negative b...

It is known that some bacteria, especially members of the family Rhizobiaceae, have multiple N-acyl homoserine lactones (AHL) synthase genes and produce multiple AHL signals. However, how bacteria selectively utilize these multiple genes and signals to cope with changing environments is poorly understood. Ensifer adhaerens is an important microorganism in terms of biotechnology, ecology and evo...