BIOFILM FORMATION INHIBITION BY PhoB IS REGULATED BY POLYPHOSPHATE LEVELS IN Escherichia coli

GRILLO PUERTAS, MARIANA; RINTOUL, MARIA REGINA; RAPISARDA, VIVIANA ANDREA

Rosario

Congreso; SAIB; 2014

Sociedad argentina de Investigación en Bioquimica y Biología Molecular

PhoB, the regulator of the two-component system phoBR that responds to media phosphate (Pi) limitation, wasdescribed as an inhibitor of biofilm formation. PhoB negatively regulates c-di-GMP, a second-messenger involved inthe molecular decision between planktonic motile and biofilm-associated bacterial lifestyles. Polyphosphate (polyP)in Escherichia coli stationary phase are modulated by media Pi concentration and its degradation triggers biofilmformation via LuxS quorum sensing system. The aim of this work was to investigate if polyP levels in stationary phase could regulate phoB, influencing biofilm formation capacity. E. coli cells were statically cultured in minimalmedium varying Pi concentration at different time of growth at 30ºC. For biofilms assays the Cristal violet techniquewas carried out. Results show that phoBR mutant forms biofilm independently of the media Pi concentration,conversely to diguanilates cyclases deficient strains that never form biofilm. When polyP level was present instationary phase, a high alkaline phosphatase activity was observed as an indicator of phoB activation. Varying mediaPi concentration, we demonstrate that fluctuation of polyP levels in stationary phase could be involved in phoBactivation/repression with the consequent regulation of biofilm formation mediated by c-di-GMP and AI-2.