INLAIN   20354
INSTITUTO DE LACTOLOGIA INDUSTRIAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Phage adsorption and characterization of phage receptors in Lactobacillus plantarum (Póster)
Autor/es:
BRIGGILER MARCÓ, M.; REINHEIMER, J.; QUIBERONI, A.
Lugar:
Tucumán, Argentina
Reunión:
Simposio; III Simposio Internacional de Bacterias Lácticas. Segundo Encuentro Red BAL Argentina; 2009
Institución organizadora:
Centro de Referencia para Lactobacilos (CERELA), CONICET
Resumen:
Lactobacillus plantarum could be used as probiotic/starter culture in the production of functional foods, but it activity could be severely affected by phage infections. The first step in the bacteriophage lytic cycle is the adsorption of the phage particle on host cell surface. This interaction is highly specific and dependent on the presence of specific recognition sites called receptors. Thus, a detailed knowledge of phages is required to develop appropriate defence tools against their infections. The aim of this work was to investigate the influence of physiological cell state and environmental (temperature, pH, presence of Ca2+) factors on adsorption of four phages (B1, B2, FAGK1 and FAGK2) on Lactobacillus plantarum ATCC 8014. Also, the nature of phage receptors was studied. Similar behaviour was observed for the four phages studied in this work. Calcium ions did not have a significant influence on phage adsorption kinetics. More than 99% of phage particles were adsorbed either in presence or absence of Ca2+ (10 mM).  Among temperatures assayed (0, 10, 20, 30, 37, 42 and 50ºC), phage adsorption was only affected at 50ºC (adsorption values < 40%), reaching its maximum (99.9%) between 30 and 42ºC. Regarding the influence of pH (5, 6, 7, 8, 9 and 10) on phage adsorption, 23-45% (pH 9) and 5-20% (pH 10) of phage particles were adsorbed after 30 min of incubation, while the highest adsorption values (99.9%) were observed from pH 5 to 7. Adsorption rates decreased (77-91%) after the thermal inactivation of cells (100ºC, 2 min); though, when 20 mg/ml of chloramphenicol (to inhibit protein-synthesis) was used, adsorption values were similar on treated and untreated cells. When purified Lb. plantarum host cell walls were assayed, proteinase K (0.10 mg/ml) and SDS (1%) treatments did not influence the phage adsorption but mutanolysin (50 U/ml) and TCA (5%) reduced it appreciably (values of adsorption <38 % and <15% respectively), thus suggesting a carbohydrate nature of the receptors. No clear inhibitory effect on phage adsorption was observed when 500 mM of several saccharides (glucose, galactose, mannose, rhamnose, ribose, glucosamine or N-acetylglucosamine) were used. Moreover, the irreversibility of phage adsorption was demonstrated for all phages studied, since after 30 min of adsorption, from 95 to 98.8% of phage particles were bound to the cell walls, and no significant amount of viral particles was released into the supernatants during the subsequent 180 min. Results obtained in this study revealed that physiological and environmental parameters have scarce influence on viability and phage adsorption on Lb. plantarum cells, thus highly restricting the possibilities of developing useful strategies to reduce phage infections in industrial environments.