Autoinducer (AI)

Autoinducers are specialized signaling molecules produced by bacteria to facilitate a process known as quorum sensing, which allows bacterial populations to coordinate gene expression in a cell-density-dependent manner (Miller & Bassler, 2001, PMID: 11594608). As the bacterial population grows, the concentration of these molecules increases; once a specific threshold is reached, the molecules bind to cognate receptors to trigger the expression of genes involved in collective behaviors (Waters & Bassler, 2005, PMID: 15948644). These behaviors include biofilm formation, virulence factor production, and antibiotic resistance, which are critical for the establishment and persistence of infections (Deep et al., 2011, PMID: 21804535). In clinical contexts, autoinducers are considered therapeutic targets for 'quorum quenching' strategies, which aim to disarm bacterial pathogenicity without directly killing the bacteria, potentially reducing the pressure for antibiotic resistance development (Zhang & Dong, 2004, PMID: 15590777). Targeted interventions include the use of enzymes that degrade the molecules, small molecule inhibitors that block their synthesis, or receptor antagonists that prevent signal detection (Nalca et al., 2006, PMID: 16484344). This approach is particularly relevant for treating chronic infections caused by pathogens like Pseudomonas aeruginosa and Staphylococcus aureus. By disrupting this communication system, therapeutic agents can render bacteria more susceptible to host immune responses and conventional antibiotics (Rampioni et al., 2014, PMID: 24741368).

Other names

Quorum sensing signaling moleculeBacterial pheromoneQuorum sensing moleculeQS signalN-acyl homoserine lactoneAutoinducing peptideAutoinducer-2

Enzymatic degradation of the signal (quorum quenching), inhibition of signal biosynthesis (synthase inhibition), and competitive or non-competitive antagonism of signal receptors.