AHL communication modules with functional devices built from the biological components of the las18, tra18, rpa18, rhl19, cin19 and esa20 quorum-sensing systems

In the biosensor, the promoter regions of lasI, rhlI, pqsA, and ambB (QS genes) controlled the fluorescent reporter genes of Turbo YFP, mTag BFP2, mNEON Green, and E2-Orange

observations are consistent with a previous report showing that AHLs preferentially partition to the biofilm, reaching concentrations 600-fold in excess of the signal concentration in the surrounding bulk liquid medium

Many QS-controlled genes relate to biofilm formation and function and may be important for some water and wastewater treatment biofilms

Frequency of QS among genome- sequenced bacteria

QS systems have been experimentally analyzed in more than 50 different bacterial species and shown to control expression of a wide spectrum of functions, including bioluminescence, virulence, symbiosis, different forms of motility, biofilm formation, production of antibiotics and toxins, and conjugation (49).

PpuI, which directs the biosynthesis of the two AHLs 3-oxo-C10 and 3-oxo-C12 as major products; PpuR, the AHL receptor; and RsaL a repressor of ppul

exogenous addition of AHLs to sludge resulted in long-lasting impacts on phenol degradation

Coordinated behaviours include bioluminescence3,4, virulence factor production5,6, secondary metabolite production7, competence for DNA uptake8,9 and biofilm formation10,11.

We focus on how quorums are detected and how quorum sensing controls group behaviours in complex and dynamically changing environments such as multi-species bacterial communities, in the presence of flow, in 3D non-uniform biofilms and in hosts during infection.

stabilization of microbial community

AHL was found to play important roles in wastewater treatment processes, in particular, formation of aerobic sludge granules

C8-HSL was chosen as a representative AHL molecule because it is one of the dominant AHL molecules in MBRs for wastewater treatment

These carboxylated AHLs facilitated the transition from a short cell to filamentous growth, with an altered carbon metabolic flux that favoured the conversion of acetate to methane and a reduced yield in cellular biomass

Deletion of genes thatproduceN-acyl-L-homoserine lactone signals resulted in an increase in denitrification activity, which wasrepressed by exogenous signal molecules.

endogenous AHL-based QS and QQ are existing and coexisting in biological wastewater treatments; the leading role for AHL-based QS or QQ phenomenon in biological wastewater treatments can be determined by bacterial AHL concentration.

explosion of findings that other bacterial species controlled genes for conjugation, exoenzyme production and antibiotic synthesis with luxI–luxR-like systems

QS represses biofilm formation in both S. aureus and V. cholerae

Pseudomonas aeruginosa is motile upstream (a QS-off phenotype), but forms biofilms downstream (a QS-on phenotype) in flowing networks

in most cases, the molecular mechanisms that underlie heterogeneity are not defined