Characterization of bacteriocins produced by PGPR Pseudomonas

FISCHER, S.; BUENO, M.; CORDERO, P.; PRINCIPE, A.; CAVIGLIASSO, A.; MORI, G

Carloz Paz, Córdoba

Congreso; XLIV Reunión Anual de SAIB; 2008

SAIB

The objective of the present study was to investigate the production of bacteriocin in native Pseudomonas spp. isolated from wheat root. Materials and methods: bacteriocin production was evaluated according to Parret et al. (2003). The supernatant of Pseudomonas was precipitated with ammonium sulphate and dialysed. Aliquots of crude bacteriocin were tested for their susceptibility to proteolytic enzymes and resistance to heat. Samples of bacteriocin were applied to a column of biogel P-100 and eluted with phosphate buffer. Fractions were collected, evaluated for antimicrobial activity an analyzed by gel SDS-PAGE. Results: Pseudomonas sp. SF4C synthesized a bacteriocin of probably high-molecular weight because it diffused near the colony. It is resistant to proteinase K and sensible at 75°C. The bacteriocin produced by Pseudomonas sp 39a diffused further from the colony than SF4c bacteriocin. It is resistant to proteinase K too, but antimicrobial activity was lost after incubation at 42°C. Clarified culture supernatant from SF4C was precipitated at 60% saturation of ammonium sulfate (crude extract). Fractions with antibacterial activity were eluted early from the biogel P100 column. These fractions were subjected to SDS-polyacrylamide gel and two bands were detected. Other studies are being carried out to determine which band is the responsible of antimicrobial activity