N-acyl homoserine lactone (AHL) is required by Erwinia carotovora subspecies for the expression of various traits, including extracellular enzyme and protein production and pathogenicity. Previous studies with E. carotovora subsp. carotovora have shown that AHL deficiency causes the production of high levels of RsmA, an RNA binding protein that functions as a global negative regulator of extrac...

Bacterial communication signals, acylated homoserine lactones (AHLs), were extracted from samples of commercial bean sprouts undergoing soft-rot spoilage. Bean sprouts produced in the laboratory did not undergo soft-rot spoilage and did not contain AHLs or AHL-producing bacteria, although the bacterial population reached levels similar to those in the commercial sprouts, 10(8) to 10(9) CFU/g. A...

The N-acyl homoserine lactone (AHL)-mediated quorum-sensing system in the phytopathogen Pseudomonas syringae pv. syringae requires the AHL synthase AhlI and the regulator AhlR, and is additionally subject to regulation by AefR. The contribution of quorum sensing to the expression of a variety of traits expected to be involved in epiphytic fitness and virulence of P syringae were examined. Both ...

SUMMARY In Gram-negative bacteria a typical quorum sensing (QS) system usually involves the production and response to acylated homoserine lactones (AHLs). An AHL QS system is most commonly mediated by a LuxI family AHL synthase and a LuxR family AHL response regulator. This study reports for the first time the presence of a LuxR family-type regulator in Xanthomonas oryzae pv. oryzae (Xoo), whi...

N-Acylhomoserine lactones (AHLs) are used as quorum-sensing signal molecules by many Gram-negative bacteria. We have reported that Microbacterium testaceum StLB037, which was isolated from the leaf surface of potato, has AHL-degrading activity. In this study, we cloned the aiiM gene from the genomic library of StLB037, which has AHL-degrading activity and shows high homology with the alpha/beta...

Many putative virulence factors of Burkholderia cenocepacia are controlled by various quorum sensing (QS) circuits. These QS systems either use N-acyl homoserine lactones (AHL) or cis-2-dodecenoic acid ("Burkholderia diffusible signal factor", BDSF) as signalling molecules. Previous work suggested that there is little cross-talk between both types of systems. We constructed mutants in B. cenoce...

The shoot endophytic biocontrol strain Pseudomonas chlororaphis subsp. aurantiaca PB-St2 produces a wide range of exoproducts, including enzymes and antibiotics. The production of exoproducts is commonly tightly regulated. In order to get a deeper insight into the regulatory network of PB-St2, the strain was systematically investigated regarding its quorum sensing systems, both on the genetic a...

The cooling water systems are used to remove heat generated in the various industries. Biofouling of the cooling water systems causes blocking of condenser pipes and the heat exchanger tubes. In many Gram-negative bacteria, N-acylhomoserine lactone (AHL) are used as quorum-sensing signal molecule and associated with biofilm formation. To investigate the relationship between quorum sensing and b...

UNLABELLED Bacteria engage in chemical signaling, termed quorum sensing (QS), to mediate intercellular communication, mimicking multicellular organisms. The LuxR family of QS transcription factors regulates gene expression, coordinating population behavior by sensing endogenous acyl homoserine lactones (AHLs). However, some bacteria (such as Escherichia coli) do not produce AHLs. These LuxR orp...