Quorum sensing autoinducers biosynthesis by biofilm cultures of Pseudomonas aeruginosa strains with different levels of the cyclic diguanozinmonophosphate

The aim of the work is to establish relationships between content of the cyclo-di-GMP and the ability of P. aeruginosa to form biofilm and synthesis of the quorum sensing system autoinducers.Materials and methods of research. Wild-type strain P. aeruginosa PA01 and P. aeruginosa strains with low (PAO1pJN2133) and high (PA01ΔwspF) levels of cyclic diguanosine monophosphate were used. Cultivation was performed in 24-well flat-bottomed plates Nuclon at37 °C in LB medium. Biofilm mass was determined in CV-test. The measurements were performed on a Smart Spec Plus spectrophotometer (Bio-Rad, Hungary) at a wavelength of 592 nm. Acyl-homserin lactones were extracted with acidified ethyl acetate and quantified by GC/MS. The cyclo-di-GMF content was determined using a Seattle reporter plasmid by measuring the fluorescence intensity of cells in biofilms.Results of the research. It was found that the strain of P. aeruginosa PA01 pJN2133, the intracellular content of cyclo-di-GMP in which was 4 times less than that in wild type strain, forms biofilms with mass in 3.5 times lower compared to P. aeruginosa PA01. P. aeruginosa PA01 ΔwspF exceeds P. aeruginosa PA01 in 1.5 times and 33 %, respectively. Even more significant difference were found mutant strains was compared. The level of cyclo-di-GMP in P. aeruginosa PA01 ΔwspF was in 5.9 times higher than in the PA01 pJN2133 strain cells, and five times higher in biofilm weight. The highest amount of quorum sensing system signalling molecules were synthesized by a strain with a low level of secondary messenger.Conclusions. There is a directly proportional relationship between the intracellular content of cyclic-di-GMP and the ability to form a biofilm: the higher content of the secondary messenger, leads to increased mass of the biofilm. The concentration of QS autoinducers in the medium is inversely related to the intracellular content of cyclic-di-GMP: it is increased in the strain with a low content of the secondary messenger and decreased in the strain with its increased level, compared to the parent strain