RAPISARDA Viviana Andrea
congresos y reuniones científicas
Polyphosphate degradation in stationary phase triggers biofilm formation via ai-2 in E. coli
GRILLO PUERTAS, M.; RINTOUL, M. R.; RAPISARDA, V. A.
Potrero de los Funes, San Luis
Congreso; XLVII Annual Meeting of SAIB; 2011
Escherichia coli maintained a high polyphosphate (polyP) level even in stationary phase when cells were grown in media containing phosphate concentration >37 mM. Here, the effect of phosphate and polyP levels on the ability to form biofilm was analyzed. PolyP levels were modulated by the phosphate concentration and/or by using deficient strains in polyphosphate kinase (ppk) and exopolyphosphatase (ppx). Biofilm formation was carried out in MT media supplemented with different phosphate concentrations in polystyrene plates at 30ºC and it was quantified by the crystal violet method. At 48 h, maximal biofilm formation was achieved between 2-10 mM. phosphate, being almost nule at concentrations >35 mM. Biofilm formation was not observed when ppk ppx and ppk ppx + /pBC29(ppk ) strains were analyzed in the whole range of phosphate concentrations. To determine if luxS/AI-2 or indol signaling quorum sensing systems are involved in the phosphate effects, deficient strains in luxS, tnaA and mtr genes were used. The luxS mutant was unable to form biofilm in sufficient phosphate media (2 mM). However, biofilm formation was observed when luxS cells were incubated with spent MT media of wild-type culture. According to our results, the polyP degradation in stationary phase is a key event that triggers AI-2 synthesis, a signal involved in biofilm formation.