RAPISARDA Viviana Andrea
congresos y reuniones científicas
MEDIA PHOSPHATE CONTENT INFLUENCES STRESS TOLERANCE AND BIOFILM FORMATION OF Lactobacillus paraplantarum CRL 1905
VILLEGAS, J. M.; ARAOZ, M.; GRILLO PUERTAS, M.; HEBERT, E. M.; RAPISARDA, V. A.
Congreso; Segunda Reunión Conjunta de Sociedades de BioCiencias; 2017
Lactic acid bacteria (LAB) comprise a group of Gram positive microorganisms commonly used in food fermentation industry. They are usually exposed to a range of stressful environmental conditions in both natural and/or industrial habitats, such as high temperature, low pH, nutrient starvation, and oxidation. Previous studies showed that media phosphate (Pi) content modulates polyphosphate (polyP) levels in different bacteria, affecting stress responses, stationary-phase survival, and biofilm formation. The aim of this work was to investigate the effect of Pi concentrations on stress resistance and biofilm formation of L. paraplantarum CRL 1905. Intracellular polyP levels of the strain grown in defined media (CDM) containing different Pi concentrations were determined. As control, CRL 1905 was grown in the routinely used rich medium MRS. It was observed that high polyP levels were maintained up to 120 h only when cells were grown in CDM supplied with 60 mM Pi. The polyP accumulation under this condition was correlated with a long-term cell survival, when compared to cells grown in CDM medium supplemented with sufficient Pi; loss of viability over time was even more pronounced in the rich medium. CRL 1905 stationary-phase cells grown in 60 mM Pi were more tolerant to high temperatures than those grown in 2 mM Pi. However, there was no correlation between media Pi concentration and resistance to acidic and oxidant conditions. The biofilm-forming capacity of L. paraplantarum under different culture conditions was characterized by microtiter plate biofilm assays. It was observed that a high Pi concentration in the medium impaired biofilm formation; this phenotype could be related to the maintenance of polyP in stationary phase. Taken together, this study contributes to a better understanding of alternative mechanisms by which beneficial bacteria can counteract several stress conditions and colonize different niches.