[The ability of the natural ketones to interact with bacterial quorum sensing systems].

The effect of the natural ketones emitted by bacteria (2-nonanone, 2-heptanone, 2-undecanone) on the functioning of the Quorum Sensing (QS) systems was studied. In this work, three lux-reporter strains containing the components of the LasI/LasR, RhlI/RhlR, LuxI LuxR QS systems were used as biosensors for the N-acyl-homoserine lactones. It was shown that at concentrations of ketones that exhibited little or no bactericidal action the ketones could modulate the QS-response by suppressing the expression of the lux-operon reporter to a greater extent than the cell viability of these strains.

[Formation of the Pseudomonas aeruginosa PAO1 biofilms in the presence of hydrogen peroxide; the effect of the AiiA gene].

In the natural ecosystems, most bacteria exist as specifically organized biofilms attached to various surfaces; the biofilms have a complex architecture and are surrounded by an exopolymeric matrix. The bacteria in the biofilms are extremely resistant to antibacterial agents. The ability of the pathogenic bacteria to produce biofilms causes serious problems in medicine.