Protease IV, a quorum sensing-dependent protease of Pseudomonas aeruginosa modulates insect innate immunity.

In Pseudomonas aeruginosa, quorum sensing (QS) plays an essential role in pathogenesis and the QS response controls many virulence factors. Using a mealworm, Tenebrio molitor as a host model, we found that Protease IV, a QS-regulated exoprotease of P. aeruginosa functions as a key virulence effector causing the melanization and death of T.

Activation of multiple transcriptional regulators by growth restriction in Pseudomonas aeruginosa.

Growth restriction by antibiotics is a common feature that pathogenic bacteria must overcome for survival. The struggle of bacteria to escape from growth restriction eventually results in development of antibiotic-resistance through the expression of a set of genes. Here we found that some physiologically important transcriptional regulators of Pseudomonas aeruginosa including QscR, a quorum sensing (QS) receptor, SoxR, a superoxide sensor-regulator, and AntR, a regulator of anthranilate-related secondary metabolism, are activated by various growth-restricted conditions.

Pleiotropic effects of acyltransferases on various virulence-related phenotypes of Pseudomonas aeruginosa.

Pseudomonas aeruginosa, an opportunistic pathogen causing various infections, expresses various virulence factors under the control of quorum sensing (QS), a cell density-sensing mechanism. Because the major signal molecules of QS are acyl homoserine lactones (acyl-HSLs), acyltransferases, the enzymes that act upon acyl group transfer could affect the QS signaling and QS-related virulence phenotypes. In this study, we overexpressed acyltransferases of P.

AntR-mediated bidirectional activation of antA and antR, anthranilate degradative genes in Pseudomonas aeruginosa.

Bidirectional activation of transcription is a peculiar regulation mode of gene expression. In this study, we show that genes involved in the metabolism of anthranilate, a precursor of biosynthesis of tryptophan and Pseudomonas quinolone signal (PQS) are regulated by this bidirectional activation of transcription. Anthranilate is degraded by anthranilate dioxygenase complex encoded by antABC operon, and AntR, a LysR-type regulator encoded by antR activates the transcription of antABC operon in the presence of anthranilate.