Short-chain fatty acids production by Bifidobacterium species in the presence of salep

BACKGROUND: Salep is obtained by grinding dried orchid tubers and used as a valuable ingredient in the food industry. Because of the glucomannan content of salep, it is thought to have prebiotic potential. However, there is little information in studies concerning the fermentation characteristics and potential prebiotic properties of salep. The objective of this study was to investigate the effect of salep on bifidobacterial growth by measuring the highest optical density (OD), calculating the specific growth rates, and determining the production of lactic acid and short-chain fatty acids (acetic, propionic, and butyric acid) as a result of bacterial fermentation. RESULT: The OD and pH values obtained in this study showed that salep was utilized as a source of assimilable carbon and energy by the Bifidobacterium species (BS). All Bifidobacterium strains produced lactic, acetic, propionic, and butyric acid, indicating that salep is readily fermented by these bacteria. Salep at 1% (w/v) showed a similar effect on bifidobacterial growth as that promoted by 1% (w/v) glucose used as a traditional carbon source. CONCLUSIONS: Bifidobacterium species can develop in media containing salep as well as in glucose and exhibit the potential to be used as new sources of prebiotics.

In vivo assay to identify bacteria with ß-glucosidase activity

Background: ß-Glucosidase assay is performed with purified or semipurified enzymes extracted from cell lysis. However, in screening studies, to find bacteria with ß-glucosidase activity among many tested bacteria, a fast method without cell lysis is desirable. In that objective, we report an in vivo ß-glucosidase assay as a fast method to find a ß-glucosidase producer strain. Results: The method consists in growing the strains for testing in a medium supplemented with the artificial substrate p-nitrophenyl-ß-glucopyranoside (pNPG). The presence of ß-glucosidases converts the substrate to p-nitrophenol (pNP), a molecule that can be easily measured in the supernatant spectrophotometrically at 405 nm. The assay was evaluated using two Bifidobacterium strains: Bifidobacterium longum B7254 strain that lacks ß-glucosidase activity and Bifidobacterium pseudocatenulatum B7003 strain that shows ß-glucosidase activity. The addition of sodium carbonate during pNP measurement increases the sensitivity of pNP detection and avoids the masking of absorbance by the culture medium. Furthermore, we show that pNP is a stable enzymatic product, not metabolized by bacteria, but with an inhibitory effect on cell growth. The ß-glucosidase activity was measured as units of enzyme per gram per minute per dry cell weight. This method also allowed the identification of Lactobacillus strains with higher ß-glucosidase activity among several lactobacillus species. Conclusion: This in vivo ß-glucosidase assay can be used as an enzymatic test on living cells without cell disruption. The method is simple, quantitative, and recommended, especially in studies screening for bacteria not only with ß-glucosidase activity but also with high ß-glucosidase activity.

Kinetic analysis and effect of culture medium and coating materials during free and immobilized cell cultures of Bifidobacterium animalis subsp. lactis Bb 12

Microencapsulation technique appears helpful for more protection of Bifidobacteria against acid inhibitory effect. The effect of medium composition and product inhibitory in free cell culture, as well as the effect of the coating materials in immobilized cells, on biomass growth, acid production and substrate utilization kinetics of Bifidobacterium animalis subsp. lactis Bb 12 in uncontrolled batch fermentation was examined. The Monod and the Luedeking and Piret equations with a product inhibition term involving toxic power terms improved model efficiency for both growth and production. The model showed that media and coating materials had an effect on toxic power terms. Cell immobilization had a positive impact on B. animalis culture. Kinetic analysis revealed the permeability of the coating material had a major impact on culture parameters; permeability increased in the following way: Gellan xanthan < Alginate chitosan < K-Carageenan-locust been, and hence growth parameters x m, maximum specific growth rate (h-1) (um) and monod constant (g lactose L-1) (K S) followed the same trend as well as the linking between growth and production. The link between the microbial environment and cell growth was highlighted by the model. It was shown that for an increasing protect effect of coating materials against environmental deleterious factors, namely a decrease of the permeability, transport limitation occurred, which was disadvantageous for cell formation.

Efeito bifidogênico do frutooligossacarídeo na microbiota intestinal de pacientes com neoplasia hematológica / Bifidogenic effect of fructooligosaccharides in the intestinal flora of patients with hematological neoplasia

OBJETIVO: Verificar o efeito bifidogênico do frutooligossacarídeo nos pacientes com neoplasias hematológicas submetidos a quimioterapia. MÉTODOS: Trata-se de um estudo clínico randomizado duplo cego, desenvolvido na Unidade de Transplante de Medula Óssea do Centro de Pesquisas Oncológicas de Florianópolis, o qual envolve 25 pacientes divididos em 2 grupos que receberam, por 15 dias, 12g de frutooligossacarídeo (n=14) ou placebo (maltodextrina) (n=11). Foram avaliados a quantidade de bifidobactérias e os valores de pH fecal antes e após a suplementação. RESULTADOS: Observou-se na população estudada o predomínio do sexo masculino (72 por cento) e a idade média de 34 anos. O grupo suplementado apresentou um aumento significante na quantidade de bifidobactérias (p<0,05) e o pH fecal não foi alterado em nenhum dos grupos. CONCLUSÃO: Verificou-se que a suplementação aumentou a quantidade de bifidobactérias, interferindo na composição da microbiota intestinal, e que não houve alteração do pH fecal.

OBJECTIVE: To verify the bifidogenic effect of fructooligosaccharides in patients with hematological neoplasia submitted to chemotherapy. METHODS: This is a clinical, randomized, double-blind study done in the Bone Marrow Transplant Unit of the Oncology Research Center of Florianopolis. It involved 25 patients divided into 2 groups who received 12g of fructooligosaccharides (n=14) for 15 days or placebo (maltodextrin) (n=11). The amount of bifidobacteria and the values of fecal pH before and after supplementation were investigated. RESULTS: Most of the studied population was male (72 percent) and the mean age was 34 years. The group that received supplementation presented a significant increase in the amount of bifidobacteria (p<0.05) and fecal pH remained unchanged in both groups. CONCLUSION: Supplementation increased the amount of bifidobacteria, interfering in the composition of the intestinal flora, but fecal pH was not affected.

El rol de los prebióticos, probióticos y simbióticos en gastroenterología / Role of prebiotics, probiotics and sinbiotics in gastroenterology

El tracto gastrointestinal es indudablemente el área más expuesta a microorganismos y antígenos dietarios. El epitelio intestinal es un importante componente de la barrera de la mucosa intestinal, el cual debe discriminar adecuadamente entre bacterias patogénicas y no-patogénicas. La flora bacteriana intestinal tiene un efecto condicionador sobre la homeostasis del intestino, entregando señales que regulan el epitelio, el sistema inmune de la mucosa y la actividad neuromuscular del intestino. Estudios han demostrado que la flora bacteriana comensal y sus componentes, son factores importantes en la patogénesis de varias enfermedades gastrointestinales, tales como la enfermedad inflamatoria intestinal, síndrome intestino irritable, cáncer de colon, enfermedad hepática crónica. Aunque estudios experimentales han demostrado que prebióticos, probióticos y simbióticos ejercen efectos antibacterianos, modulación inmune y antiinflamatorios, lo cual puede ser beneficioso en algunas enfermedades gastrointestinales, su real papel en el ser humano aún debe ser evaluado. Porque no todos poseen el mismo efecto terapéutico, colonización con específicos probióticos y simbióticos (incluyendo la ingeniería bacteriana para secretar citokinas anti-inflamatorias y restaurar la flora comensal y la tolerancia intestinal) podría ser la próxima estrategia para el tratamiento de las enfermedades gastrointestinales y otras enfermedades inmunológicas.

Interaction of bifidobacteria with the gut and their influence in the immune function

Bifidobacteria are predominant in the lumen of the large intestine and confer various health benefits on the host. They are also used in the preparation of new fermented milks (bioyogurts) or added to conventional yogurt to generate probiotic effects. The colonization of the gut by bacteria tends to be host specific due partly to the way in which bacteria adhere to the intestinal wall. Using a homologous strain of Bifidobacterium animalis in an experimental mouse model, we analyzed by immunofluorescence labelled-bacteria and transmission electronic microscopy the importance of the bacterial interaction with epithelial an immune cells associated to the gut, and the effect of feeding of B. animalis in the immune response. It was able to adhere and interact with both small and large intestine. In spite of this interaction with the gut, no modifications in the immune state (secretory or systemic response) were observed. A heterologous strain of Bifidobacterium adolescentis from human faeces, was neither incapable of binding to the intestine, nor influence the immune system activation, when it was administered during 2, 5 or 7 consecutive days; we believe that using a homologous strain, oral tolerance is developed even when the microorganism interacts with the immune cells associated with the intestine. However, we cannot ignore the beneficial effect of these microorganisms, especially in the prevention of intestinal infections. We think that this property exerted by bifidobacteria is more related to other mechanisms such as competitive inhibition, acid production or others, than enhancement of the immune state.

Evaluación de la actividad de cultivos probióticos sobre Listeria monocytogenes durante la producción y almacenamiento de yogur / Evaluation of the activity of probiotic cultures over Listeria monocytogenes during the production and storage of yogurt

The effect of probiotic cultures over Listeria monocytogenes during the production and storage of yogurt was evaluated. A yogurt mixture (10.6 per cent non-fat solid liquids, 3 per cent fat and 0.3 per cent gelatin) was prepared, homogenized and pasteurized. Yogurt was inoculated with 0, 10(2), 10(4) and 10(6) CFU/mL of L. monocytogenes and 0.02 per cent of traditional lactic culture YC 180 (Streptococcus thermophilus and Lactobacillus bulgaricus) and probiotic culture ABY-1 (Bifidobacterium longum, B. bifidum, B, infantis, Lactobacillus acidophilus, Streptococcus thermophilus y Lactobacillus delbrueckii subsp. bulgaricus). It was incubated for 3 h at 43 degrees C until pH reached an approximate value of 4.8, followed by refrigeration at 5 degrees C for 21 days. During fermentation, samples were taken every hour, and during storage every 3 days, analyzing pH and lactic, bifidobacteria and pathogen count for each time. It was demonstrated that there was no significant simple effect for the type of culture used (ABY-1 and YC 180) (p = 0.684) over the amount of L. monocytogenes present in yogurt during the fermentation and storage periods. The presence of bifidobacteria in the ABY-1 culture did not present a significant effect over L. monocytogenes. Neither the effect of time presented a significant effect over L. monocytogenes (p = 0.448). In this case, the ABY-1 and YC 180 cultures present a bacteriostatic effect over the pathogen. The probiotic cultures had a bacteriostatic but not bactericidal effect over L. monocytogenes. This is not related to the protective effect of these cultures in bowel, since in-vivo conditions favor the production of antimicrobial substances, such as bacteriocins that act over pathogens.

Cambio en la flora intestinal de ratones por la administración de bifidobacterias y jugo de girasol / Intestinal microflora changes in mice by bifidobacteria and sunflower juice

Entre los microorganismos intestinales que tienen efectos metabólicos importantes e interacciones benéficas con el hospedero están las bifidobacterias. La implantación y sobrevivencia de este microorganismo cuando se administra como probiótico dependerá en gran medida del tipo de dieta que el huésped consuma, la cual puede promover o no la proliferación de las bifidobacterias. En este estudio se investigó el efecto de los polifructanos del jugo de girasol como promotores de la proliferación de los bífidos en el intestino de ratón y su influencia en la composición de la flora intestinal. Se administró a una población de ratones, jugos de girasol y bifidobacterias. Los ratones que se alimentaron con jugo de girasol y bifidobacterias mostraron una disminución relativa de enterobacterias, estafilococos, estreptococos y lactobacilos, así como un aumento de los anaerobios totales. Se observa que la implantación de bifidobacterias administradas exógenamente es mayor cuando se complementa con la administración de jugo de girasol