CERELA   05438
CENTRO DE REFERENCIA PARA LACTOBACILOS
Unidad Ejecutora - UE
artículos
Título:
Phage-resistant mutants of Lactobacillus delbrueckii may have functional properties that differ from those of parent strains
Autor/es:
VINDEROLA, CELSO GABRIEL; MARCO, R.B.; GUGLIEMOTTI, D.M.; PERDIGON, G.; GIRAFFA, G.; REINHEIMER, J.; QUIBERONI, A.
Revista:
INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY
Referencias:
Año: 2006 vol. 116
ISSN:
0168-1605
Resumen:
Three commercial phage sensitive Lactobacillus delbrueckii strains (identified as Ab1, YSD V and Ib3), and four spontaneous phage-resistant
mutants isolated from them were tested for their capacity to activate the gut mucosal immune response in mice, as indicated by the numbers of
IgA-producing cells. Random Amplified Polymorphic DNA (RAPD) analysis revealed a strong genetic homology between the sensitive strains
and their respective derivatives. The phage-resistant mutants exhibited high levels of phage resistance, elevated stability of this phenotype and
technological properties comparable to those of their respective parent strains. The tolerance to acidic conditions, bile salts and lysozyme was
strain dependent and total cell viability losses as a result of exposure to all three stresses ranged from 2.0 to 3.7 log units. All the strains were
highly resistant to a simulated gastric solution of pH 3, while significant additional losses in cell viability were observed when acid treated cells
were exposed to bile salts and lysozyme. BALB/c mice received pure cultures of Lb. delbrueckii sensitive and phage-resistant strains for 2, 5 or
7 consecutive days. The ability of the parent strains to activate the small intestine immune response was preserved or enhanced in phage-resistant
mutants. The maximal proliferation of IgA+ cells was observed at day 5 or 7, depending on the strain. Mutants isolated in this study using natural
selection strategies had improved phage resistance, adequate technological properties and satisfactory gut mucosal immunostimulation ability, and
so would be good candidates for industrial applications in functional foods.Lactobacillus delbrueckii strains (identified as Ab1, YSD V and Ib3), and four spontaneous phage-resistant
mutants isolated from them were tested for their capacity to activate the gut mucosal immune response in mice, as indicated by the numbers of
IgA-producing cells. Random Amplified Polymorphic DNA (RAPD) analysis revealed a strong genetic homology between the sensitive strains
and their respective derivatives. The phage-resistant mutants exhibited high levels of phage resistance, elevated stability of this phenotype and
technological properties comparable to those of their respective parent strains. The tolerance to acidic conditions, bile salts and lysozyme was
strain dependent and total cell viability losses as a result of exposure to all three stresses ranged from 2.0 to 3.7 log units. All the strains were
highly resistant to a simulated gastric solution of pH 3, while significant additional losses in cell viability were observed when acid treated cells
were exposed to bile salts and lysozyme. BALB/c mice received pure cultures of Lb. delbrueckii sensitive and phage-resistant strains for 2, 5 or
7 consecutive days. The ability of the parent strains to activate the small intestine immune response was preserved or enhanced in phage-resistant
mutants. The maximal proliferation of IgA+ cells was observed at day 5 or 7, depending on the strain. Mutants isolated in this study using natural
selection strategies had improved phage resistance, adequate technological properties and satisfactory gut mucosal immunostimulation ability, and
so would be good candidates for industrial applications in functional foods.Lb. delbrueckii sensitive and phage-resistant strains for 2, 5 or
7 consecutive days. The ability of the parent strains to activate the small intestine immune response was preserved or enhanced in phage-resistant
mutants. The maximal proliferation of IgA+ cells was observed at day 5 or 7, depending on the strain. Mutants isolated in this study using natural
selection strategies had improved phage resistance, adequate technological properties and satisfactory gut mucosal immunostimulation ability, and
so would be good candidates for industrial applications in functional foods.+ cells was observed at day 5 or 7, depending on the strain. Mutants isolated in this study using natural
selection strategies had improved phage resistance, adequate technological properties and satisfactory gut mucosal immunostimulation ability, and
so would be good candidates for industrial applications in functional foods.