Being an inhabitant of all environments, from aquatic to terrestrial, from soil to distilled water, from plants to humans, P. aeruginosa is the quintessence of microbial arms depot. It produces a wide range of secondary metabolites to protect its niche from other fungi and distantly related bacteria. In order to fight fellow Pseudomonads and other closely related bacterial species that may compete for common niches, all strains of P. aeruginosa also produce a broad range of bacteriocins referred to as pyocins. The two major groups of pyocins produced by P. aeruginosa are (i) S-type pyocins (colicin-like bacteriocins), (ii) Tailocins (high-molecular weight bacteriocins that resemble phage tails).
S-type pyocins are colicin-like bacteriocins produced by P. aeruginosa. They are soluble, protease and heat sensitive, and are encoded in the bacterial chromosome. S-type pyocins are produced inside the cells as binary complexes where the large active protein (the toxin) is tightly bound to a smaller …show more content…
Transmission Electron Micrographs of R-type and F-type Pyocins. A. A P. aeruginosa lysate containing F-type pyocins. B. A P. aeruginosa lysate containing R-type pyocins. C. A P. aeruginosa lysate containing R-type and F-type pyocins. Red arrows point at F-type pyocins and green arrows at R-type pyocins.
All the species that have been found to produce R-type and F-type tailocins to date are listed in Table 1.1. The gene organization of different R-type tailocin gene clusters of different species can vary. F-type pyocin genes can also differ between species, for example the sequences of fibers of F-type tailocins of Listeria monocytogenes (monocins) are completely different from those of F-type pyocins of P. aeruginosa. Further, the tail tip of F-type pyocins and monocins look distinct from each other when visualized under an electron microscope [26]. Hence tailocins in different bacteria have probably been derived from evolutionarily distinct
S-type pyocins are colicin-like bacteriocins produced by P. aeruginosa. They are soluble, protease and heat sensitive, and are encoded in the bacterial chromosome. S-type pyocins are produced inside the cells as binary complexes where the large active protein (the toxin) is tightly bound to a smaller …show more content…
Transmission Electron Micrographs of R-type and F-type Pyocins. A. A P. aeruginosa lysate containing F-type pyocins. B. A P. aeruginosa lysate containing R-type pyocins. C. A P. aeruginosa lysate containing R-type and F-type pyocins. Red arrows point at F-type pyocins and green arrows at R-type pyocins.
All the species that have been found to produce R-type and F-type tailocins to date are listed in Table 1.1. The gene organization of different R-type tailocin gene clusters of different species can vary. F-type pyocin genes can also differ between species, for example the sequences of fibers of F-type tailocins of Listeria monocytogenes (monocins) are completely different from those of F-type pyocins of P. aeruginosa. Further, the tail tip of F-type pyocins and monocins look distinct from each other when visualized under an electron microscope [26]. Hence tailocins in different bacteria have probably been derived from evolutionarily distinct