Many Gram-negative bacteria employ a mechanism of cell-cell communication known as quorum sensing (QS). The role of QS is to enable the cells in a culture to coordinate their gene expression profile with changes in the population cell density. The best characterized mechanisms of QS employ N-acylated homoserine lactones (AHLs) as signalling molecules. These AHLs are made by enzymes known as Lux...

Many Proteobacteria are capable of quorum sensing using N-acyl-homoserine lactone (acyl-HSL) signaling molecules that are synthesized by LuxI or LuxM homologs and detected by transcription factors of the LuxR family. Most quorum-sensing species have at least one LuxR and one LuxI homolog. However, members of the Escherichia, Salmonella, Klebsiella, and Enterobacter genera possess only a single ...

The genome of the acidophilic, proteobacterium Acidithiobacillusferrooxidans, contains linked but divergently oriented genes, termed afel and afeR, whose predicted protein products are significantly similar to the LuxI and LuxR families of proteins. A possible promoter and Lux box are predicted upstream of afel. A cloned copy of afel, expressed in E. coli, encodes an enzyme that catalyzes the p...

Pseudomonas syringae pv. actinidiae (Psa) is an emerging phytopathogen causing bacterial canker disease in kiwifruit plants worldwide. Quorum sensing (QS) gene regulation plays important roles in many different bacterial plant pathogens. In this study we analyzed the presence and possible role of N-acyl homoserine lactone (AHL) quorum sensing in Psa. It was established that Psa does not produce...

It is well recognized that bacteria communicate via small diffusible molecules, a process termed quorum sensing. The best understood quorum sensing systems are those that use acylated homoserine lactones (AHLs) for communication. The prototype of those systems consists of a LuxI-like AHL synthase and a cognate LuxR receptor that detects the signal. However, many proteobacteria possess LuxR rece...

Synthetic biology seeks to enable programmed control of cellular behavior though engineered biological systems. These systems typically consist of synthetic circuits that function inside, and interact with, complex host cells possessing pre-existing metabolic and regulatory networks. Nevertheless, while designing systems, a simple well-defined interface between the synthetic gene circuit and th...

In the behavior known as quorum sensing (QS), bacteria release diffusible signal molecules known as autoinducers, which by accumulating in the environment induce population-wide changes in gene expression. Although QS has been extensively studied in well-mixed systems, the ability of diffusing QS signals to synchronize gene expression in spatially extended colonies is not well understood. Here ...

Vibrio fischeri quorum sensing involves the LuxI and LuxR proteins. The LuxI protein generates the quorum-sensing signal N-3-oxohexanoyl-l-homoserine lactone (3OC6-HSL), and LuxR is a signal-responsive transcriptional regulator which activates the luminescence (lux) genes and 17 other V. fischeri genes. For activation of the lux genes, LuxR binds to a 20-base-pair inverted repeat, the lux box, ...

The Vibrio fischeri quorum-sensing signal N-3-oxohexanoyl-l-homoserine lactone (3OC6-HSL) activates expression of the seven-gene luminescence operon. We used microarrays to unveil 18 additional 3OC6-HSL-controlled genes, 3 of which had been identified by other means previously. We show most of these genes are regulated by the 3OC6-HSL-responsive transcriptional regulator LuxR directly. This dem...