Functional synergism of pyoverdine and the S-type pyocins of Pseudomonas aeruginosa / 生物工程学报

Pyocin S2 and S4 in Pseudomonas aeruginosa use the same uptake channels as the pyoverdine does in bacteria, indicating a possible connection between them. In this study, we characterized the single bacterial gene expression distribution of three S-type pyocins (Pys2, PA3866, and PyoS5) and examined the impact of pyocin S2 on bacterial uptake of pyoverdine. The findings demonstrated that the expression of the S-type pyocin genes was highly differentiated in bacterial population under DNAdamage stress. Moreover, exogenous addition of pyocin S2 reduces the bacterial uptake of pyoverdine so that the presence of pyocin S2 prevents the uptake of environmental pyoverdine by non-pyoverdine synthesizing 'cheaters', thereby reducing their resistance to oxidative stress. Furthermore, we discovered that overexpression of the SOS response regulator PrtN in bacteria significantly decreased the expression of genes involved in the synthesis of pyoverdine, significantly decreasing the overall synthesis and exocytosis of pyoverdine. These findings imply a connection between the function of the iron absorption system and the SOS stress response mechanism in bacteria.

Biophysicochemical characterization of Pyocin SA189 produced by Pseudomonas aeruginosa SA189

Abstract Pseudomonas aeruginosa, in spite of being a ubiquitous organism (as it is found in soil, water, and humans), is also an opportunistic pathogen. In order to maintain its diversity in the community, it produces various toxic proteins, known as, bacteriocins. In the present study, pyocin SA189, which is a bacteriocin produced by P. aeruginosa SA189 (isolated from a clinical sample) was characterized. P. aeruginosa SA189, as identified by the conventional and 16S rRNA gene amplification, produced pyocin SA189 of molecular weight of 66 k Da. The pyocin showed antimicrobial activity against several clinically relevant Gram-positive and Gram-negative bacteria and was substantially stable for wide ranges of temperature and pH. Furthermore, the pyocin also retained its biological activity upon treatment with metal ions, organic solvents, and various proteolytic and lipolytic enzymes. The data from the growth kinetics indicated that the maximum bacteriocin production occurred in the late log phase. Overall, our results signify the potential of pyocin SA189 as a bio-control agent.