Effects of the bacteriocin PsVP-10 produced by Pseudomonas sp. on sensitive bacterial strains.

The bacteriocin PsVP-10 is a 2.6 Kda peptide which was isolated and purified from Pseudomonas sp. This bacteriocin possesses lethal activity over Enterococcus faecalis, Salmonella typhimurium and Shigella flexneri. The experimental assays showed that the bacteriocin is able to be adsorbed by all cells of these bacterial species and also by their isolated cell walls. It was observed that the resistant mutants and their respective cell walls are unable to adsorb the bacteriocin. Assays performed with spheroplasts obtained from sensitive bacterial species and their resistant mutants show a rapid lethal effect of the bacteriocin PsVP-10. This results indicated furthermore, it is also shown that the optimal pH and temperature for the adsorption were 7.2 and 37 degrees C, respectively. The study carried out with organic solvents like methanol, ethanol, isopropanol and the detergents sodium dodecyl sulfate and triton X-100 showed a moderate inhibition of the bacteriocin lethal action for the Gram negative cells. The enzymes lysozime, protease XIV and trypsine type III-S did not present any effect over the adsorption capacity of the bacteriocin with any of the bacterial species studied.