Deinococcus radiodurans can interfere with quorum sensing by producing an AHL-acylase and an AHL-lactonase

Abstract

Bacterial communication via the secretion of small diffusible compounds allows microorganisms to regulate gene expression in a coordinated manner. As many virulence traits are regulated in this fashion, disruption of chemical communication has been proposed as novel antimicrobial therapy. Quorum-quenching enzymes have been a promising discovery in this field as they interfere with the communication of Gram-negative bacteria. AHL-lactonases and AHL-acylases have been described in a variety of bacterial strains; however, usually only one of these two groups of enzymes has been described in a single species. We report here the presence of a member of each group of enzymes in the extremophile bacterium Deinococcus radiodurans. Co-occurrence of both enzymes in a single species increases the chance of inactivating foreign AHL signals under different conditions. We demonstrate that both enzymes are able to degrade the quorum-sensing molecules of various pathogens subsequently affecting virulence gene expression. These studies add the quorum-quenching enzymes of D. radiodurans to the list of potent quorum-quenchers and highlight the idea that quorum quenching could have evolved in some bacteria as a strategy to gain a competitive advantage by altering gene expression in other species.

Keywords: acyl homoserine lactone; acylase; extremophile; lactonase; quorum sensing.