Messing with Bacterial Quorum Sensing

Abstract

SUMMARY Quorum sensing is widely recognized as an efficient mechanism to regulate expression of specific genes responsible for communal behavior in bacteria. Several bacterial phenotypes essential for the successful establishment of symbiotic, pathogenic, or commensal relationships with eukaryotic hosts, including motility, exopolysaccharide production, biofilm formation, and toxin production, are often regulated by quorum sensing. Interestingly, eukaryotes produce quorum-sensing-interfering (QSI) compounds that have a positive or negative influence on the bacterial signaling network. This eukaryotic interference could result in further fine-tuning of bacterial quorum sensing. Furthermore, recent work involving the synthesis of structural homologs to the various quorum-sensing signal molecules has resulted in the development of additional QSI compounds that could be used to control pathogenic bacteria. The creation of transgenic plants that express bacterial quorum-sensing genes is yet another strategy to interfere with bacterial behavior. Further investigation on the manipulation of quorum-sensing systems could provide us with powerful tools against harmful bacteria.

Anti-quorum sensing activity of phenolic extract from Eugenia brasiliensis (Brazilian cherry)

“…This process occurs through the production, release and detection of signaling molecules by bacterial cells (González & Keshava, 2006). The signaling molecules are usually termed as autoinducers belonging to the acyl homoserine lactone (AHL) group, commonly referred to as autoinducer 1 (AI-1), which are used by Gram-negative bacteria; autoinducer peptides (AIP) used by Gram-positive bacteria; and autoinducer 2 type molecules (AI-2) used by both groups.…”

“…A disruption in any of the steps required for the quorum sensing communication could interfere with microbial pathogenesis and aid in bacterial control (González & Keshava, 2006;. This approach is part of a broader group of antivirulence strategies (Rasko & Sperandio, 2010).…”

Biossurfactantes: propriedades anticorrosivas, antibiofilmes e antimicrobianas

“…Estes componentes podem ser alguns fatores de virulência de natureza proteica e ainda de quorum sensing: elastase, protease LasA, protease alcalina, fosfolipase C, lipase, exotoxina A, cianeto, piocianina, lectina e superóxido dismutase; que têm produção coordenada por quorum sensing e a mesma ocorre concomitantemente à produção de ramnolipídios por P. aeruginosa. 91,92 As moléculas que possuem atividade quorum sensing produzidas por P. aeruginosa também podem interferir sobre o comportamento de outros micro--organismos que não produzem os mesmos sinais, um exemplo é o 3-oxo-C 12 -HSL (sistema LasI/R) e o PQS que apresentam excelentes propriedades antibacterianas.…”

Single Cell Time-resolved Quorum Responses Reveal Dependence on Cell Density and Configuration

“…Expression of quorum-controlled genes is negligible or absent at low cellular density. When the number of bacteria in an environment reaches a critical level, the AI in the medium exceeds a threshold concentration and binds to regulatory receptor proteins, and the AI-receptor complex induces or represses the expression of genes that are under quorum regulation (5)(6)(7)(8)(9). The AI gene is usually one of the target genes under quorum control, creating a positive feedback loop for AI production, which causes a spike in AI expression.…”

“…In a population of bacteria, the number of cells in the "on" and "off" state with respect to quorum sensing will vary with the AI concentration in the extracellular environment (5)(6)(7)11). Studying communication between bacteria is important for understanding the mechanism of quorum sensing in different environments.…”