Characterization of liposomes coated with S-layer proteins from lactobacilli

The stability of liposomes coated with S-layer proteins from Lactobacillus brevis and Lactobacillus kefir was analyzed as a previous stage to the development of a vaccine vehicle for oral administration. The interactions of the different S-layer proteins with positively charged liposomes prepared with soybean lecithin or dipalmitoylphosphatidylcholine were studied by means of the variation of the Z potential at different protein-lipid ratios, showing that both proteins were able to attach in a greater extent to the surface of soybean lecithin liposomes. The capacity of these particles to retain carboxyfluorescein or calcein by exposure to bile salts, pancreatic extract, pH change and after a thermal shock showed that both S-layer proteins increased the stability of the liposomes in the same magnitude. The non-glycosylated protein from L. brevis protects more efficiently the liposomes at pH 7 than those from L. kefir even without treatment with glutaraldehyde.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Revalorización del residuo sólido de levaduras cerveceras como aditivo en la alimentación de aves con potencial probiótico

La producción de cerveza, la bebida alcohólica mundialmente más consumida, conlleva la generación de residuos sólidos, como el bagazo de malta y las levaduras floculadas. Estas últimas, de elevados valor nutritivo y carga orgánica, suponen un problema de descarte para los cerveceros artesanales, que impone costos de pre-tratamiento inasequibles para el sector. Esta investigación propone la revalorización del residuo de levaduras cerveceras (RLC) como aditivo para la alimentación avícola, a partir del estudio de sus propiedades tecnológicas y probióticas

Survival of spray-dried Lactobacillus kefir is affected by different protectants and storage conditions

Survival of two Lactobacillus kefir strains after spray drying in reconstituted skim milk with or without the addition of 12.5 g monosodium glutamate/l, 20 g sucrose/l, or 20 g fructo-oligosaccharides (FOS)/l and during subsequent storage under different conditions of temperature (20 and 30°C) and relative humidity (0, 11 and 23%) was evaluated. After being dried, Lactobacillus kefir 8321 and L. kefir 8348 had a decrease in viability of 0.29 and 0.70 log c.f.u./ml respectively, while the addition of different protectants improved the survival of both strains significantly. During storage, bacterial survival was significantly higher under lower conditions of relative humidity (0-11%), and monosodium glutamate and FOS proved to be the best protectants.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Characterization of liposomes coated with S-layer proteins from lactobacilli

The stability of liposomes coated with S-layer proteins from Lactobacillus brevis and Lactobacillus kefir was analyzed as a previous stage to the development of a vaccine vehicle for oral administration. The interactions of the different S-layer proteins with positively charged liposomes prepared with soybean lecithin or dipalmitoylphosphatidylcholine were studied by means of the variation of the Z potential at different protein-lipid ratios, showing that both proteins were able to attach in a greater extent to the surface of soybean lecithin liposomes. The capacity of these particles to retain carboxyfluorescein or calcein by exposure to bile salts, pancreatic extract, pH change and after a thermal shock showed that both S-layer proteins increased the stability of the liposomes in the same magnitude. The non-glycosylated protein from L. brevis protects more efficiently the liposomes at pH 7 than those from L. kefir even without treatment with glutaraldehyde.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Lactobacillus plantarum isolated from kefir: Protection of cultured Hep-2 cells against Shigella invasion

Two types of microbial mixtures containing selected lactic acid bacteria and yeasts isolated from kefir grains were tested against the Shigella invasion of Hep-2 cells in culture. A five-strain mixture demonstrated a significant inhibition of the cell internalisation of Shigella flexneri and Shigella sonnei. The addition of single kefir strains or their mixtures to the cells, before the addition of Shigella, protected more efficiently than the simultaneous addition of the lactic-acid bacteria and Shigella on the cells. Among the kefir strains assayed, Lactobacillus plantarum strain CIDCA 83114 showed the most significant inhibition of the invasion. Both the cell walls of L. plantarum and the intact bacterial cells demonstrated an equivalent protection of cell monolayers; with the possibility of a protein or peptide mediating this effect. These results provide evidence for the potential inhibitory properties of certain kefir strains, such as L. plantarum CIDCA 83114, against disease-producing species of Shigella.Fil: Kakisu, Emiliano Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigaciones En Criotecnología de Alimentos (i); Argentina. Universidad Nacional de La Plata; ArgentinaFil: Bolla, Patricia Araceli. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas. Cátedra de Microbiología General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigaciones en Criotecnología de Alimentos (i); Argentina. Universidad Nacional de La Plata; ArgentinaFil: Abraham, Analia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigaciones En Criotecnología de Alimentos (i); Argentina. Universidad Nacional de La Plata; ArgentinaFil: De Urraza, Patricio. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas. Cátedra de Microbiología General; ArgentinaFil: De Antoni, Graciela L.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigaciones en Criotecnología de Alimentos (i); Argentina. Universidad Nacional de La Plata; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentin

Protective effect of bifidobacteria in an experimental model of Clostridium difficile associated colitis

The aim of this study was to evaluate the ability of Bifidobacterium strains to prevent the effects associated with Clostridium difficile infection in a hamster model of enterocolitis. After clindamycin treatment (30 mg/kg), animals were infected intragastrically with C. difficile (5 × 108 CFU per animal). Seven days prior to antibiotic administration, probiotic treatment was started by administering bacterial suspensions of bifidobacteria in drinking water. Strains CIDCA 531, CIDCA 5310, CIDCA 5316, CIDCA 5320, CIDCA 5323 and CIDCA 5325 were used. Treatment was continued during all the experimental period. Development of diarrhoea, enterocolitis and mortality were evaluated. All the infected animals belonging to the placebo group developed enterocolitis (5/5) and only two dead (2/5) whereas in the group administered with Bifidobacterium bifidum strain CIDCA 5310 the ratio of animals with enterocolitis or dead decreased significantly (1/5 and 0/5 respectively). Biological activity of caecum contents was evaluated in vitro on Vero cells. Animals treated with strain CIDCA 5310 presented lower biological activity than those belonging to the placebo group. The present study shows the potential of selected strains of bifidobacteria to antagonise, in vivo, the virulence of C. difficile.Fil: Trejo, Fernando Miguel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Perez, Pablo Fernando. Universidad Nacional de La Plata; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: De Antoni, Graciela L. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina. Universidad Nacional de La Plata; Argentin