RESUMEN

Limosilactobacillus fermentum NCC 2970 GtfB (Lf2970 GtfB) is the only characterized 4,3-α-glucanotransferase (4,3-α-GTase) in the glycoside hydrolase (GH) 70 family belonging to the GtfB subfamily. However, the mechanism for its (α1 → 3) linkage formation remains unclear, and the structural determinants of its linkage specificity remain to be explored. Here, sequence alignment and structural comparison were conducted to identify key amino acids that may be critical for linkage specificity. Five residues of Lf2970 GtfB (D991, G1028, A1398, T1400, and E1405), located at donor and acceptor subsites, were selected for mutation. Product structure analysis revealed that D991 and G1028, located near the acceptor binding subsites, played crucial roles in linkage formation. Besides native (α1 → 4) and (α1 → 3) linkages, mutants G1028R and D991N showed 8 and 10% (α1 → 6) linkage increases compared to 1% for wild-type in products. Additionally, molecular docking studies demonstrated that the orientation of acceptor binding in G1028R and D991N mutants was favorable for (α1 → 6) linkage synthesis. However, the mutation at positions A1398, T1400, and E1405 indicated that the donor subsites contribute less to the linkage specificity. These results shed light on the structural determinants of linkage specificity of 4,3-α-GTase Lf2970 GtfB and provided insights into the structure-function relationship of family GH70.

Asunto(s)

Proteínas Bacterianas , Glucanos , Limosilactobacillus fermentum , Limosilactobacillus fermentum/enzimología , Limosilactobacillus fermentum/metabolismo , Limosilactobacillus fermentum/genética , Limosilactobacillus fermentum/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Glucanos/metabolismo , Glucanos/química , Sistema de la Enzima Desramificadora del Glucógeno/metabolismo , Sistema de la Enzima Desramificadora del Glucógeno/genética , Sistema de la Enzima Desramificadora del Glucógeno/química , Mutación , Especificidad por Sustrato , Secuencia de Aminoácidos , Alineación de Secuencia

RESUMEN

Lactic acid bacteria (LAB) can convert inorganic selenium (Se) to organic Se and elemental forms with low toxicity and high bioavailability, but a comprehensive Se analysis of Se-enriched LAB is lacking. In this study, Limosilactobacillus fermentum Ln-9 was obtained by intense pulsed light-ultraviolet combined mutagenesis, and its characteristics and subcellular localization of Se were analyzed. The results displayed that Ln-9 accumulated 3.03 times Se that of the original strain. Under optimal fermentation conditions, the total Se content of Se-enriched Ln-9 (SeLn-9) reached 12.16 mg/g with 96.34% contained in Se nanoparticles (SeNPs), which was much higher than that of organic macromolecules. Furthermore, SeNPs were mainly localized outside the cell, Se-proteins were in the membrane and cytoplasmic fractions, and Se-polysaccharides were in the membrane fraction. Besides, SeLn-9 maintained a good morphology and gastrointestinal tolerance and had an enhanced antioxidant capacity. These findings make Ln-9 promising for applications in the food industry.

Asunto(s)

Limosilactobacillus fermentum , Mutagénesis , Selenio , Rayos Ultravioleta , Selenio/metabolismo , Selenio/química , Limosilactobacillus fermentum/metabolismo , Limosilactobacillus fermentum/genética , Limosilactobacillus fermentum/química , Fermentación , Antioxidantes/química , Antioxidantes/metabolismo

RESUMEN

Lactic acid bacteria (LAB) produce a broad spectrum of exopolysaccharides (EPSs), commonly used as texturizers in food products. Due to their potential contribution to LAB probiotic properties, like adhesion to human epithelial cells and competitive exclusion of pathogens from human intestinal epithelial cells, this study was focussed on the structural and functional characterization of the EPSs produced by two Limosilactobacillus fermentum strains - MC1, originating from mother's milk, and D12, autochthonous from Croatian smoked fresh cheese. Whole-genome sequencing and functional annotation of both L. fermentum strains by RAST server revealed the genes involved in EPS production and transport, with some differences in functionally related genes. EPSs were extracted from the cell surface of both bacterial strains and purified by size-exclusion chromatography. Structural characterization of the EPSs, achieved by chemical analyses and 1D and 2D NMR spectroscopy, showed that both strains produce an identical mixture of three different EPSs containing galactofuranose and glucopyranose residues. However, a comparison of the functional properties showed that the MC1 strain adhered better to the Caco-2 cell line and exhibited stronger antimicrobial effect against Salmonella enterica serovar Typhimurium FP1 than the D12 strain, which may be attributed to the potential bacteriocin activity of the MC1 strain.

Asunto(s)

Limosilactobacillus fermentum , Polisacáridos Bacterianos , Humanos , Limosilactobacillus fermentum/metabolismo , Limosilactobacillus fermentum/química , Células CACO-2 , Polisacáridos Bacterianos/química , Polisacáridos Bacterianos/farmacología , Salmonella typhimurium/efectos de los fármacos , Adhesión Bacteriana/efectos de los fármacos

RESUMEN

The role of microbiota in gut-brain communication has led to the development of probiotics promoting brain health. Here we report a genomic study of a Lactobacillus fermentum PS150 and its patented bioactive protein, elongation factor Tu (EF-Tu), which is associated with cognitive improvement in rats. The L. fermentum PS150 circular chromosome is 2,238,401 bp and it consists of 2281 genes. Chromosome comparisons with other L. fermentum strains highlighted a cluster of glycosyltransferases as potential candidate probiotic factors besides EF-Tu. Molecular evolutionary analyses on EF-Tu genes (tuf) in 235 bacteria species revealed one to three copies of the gene per genome. Seven tuf pseudogenes were found and three species only possessed pseudogenes, which is an unprecedented finding. Protein variability analysis of EF-Tu showed five highly variable residues (40 K, 41G, 42 L, 44 K, and 46E) on the protein surface, which warrant further investigation regarding their potential roles as binding sites.

Asunto(s)

Encéfalo/fisiología , Evolución Molecular , Limosilactobacillus fermentum/química , Factor Tu de Elongación Peptídica/química , Proteínas/química , Humanos , Conformación Proteica

RESUMEN

Exopolysaccharides (EPS) production is a characteristic that has been widely described for many lactic acid bacteria (LAB) of different genera and species, but little is known about the relationship between the functional properties of the producing bacteria and EPS synthesis. Although many studies were addressed towards the application of EPS-producing LAB in the manufacture of several dairy products (fermented milk, cheese) due to their interesting technological properties (increased hardness, water holding capacity, viscosity, etc.), there are not many reports about the functional properties of the EPS extract itself, especially for the genus Lactobacillus. The aim of the present revision is to focus on the species Lactobacillus fermentum with reported functional properties, with particular emphasis on those strains capable of producing EPS, and try to establish if there is any linkage between this property and their functional/probiotic roles, considering the most recent bibliography.

Asunto(s)

Productos Lácteos Cultivados/microbiología , Microbiología de Alimentos , Limosilactobacillus fermentum/fisiología , Polisacáridos Bacterianos/biosíntesis , Animales , Antibiosis , Bacterias/patogenicidad , Fenómenos Fisiológicos Bacterianos , Fermentación , Factores Inmunológicos , Limosilactobacillus fermentum/química , Probióticos/metabolismo

RESUMEN

The aim of this study was to assess the protective effect of the intracellular content obtained from potential probiotic bacteria against acrylamide-induced oxidative damage in human erythrocytes. First, the antioxidant properties of 12 potential probiotic strains was evaluated. Two commercial probiotic bacteria were included as reference strains, namely, Lactobacillus casei Shirota and Lactobacillus paracasei 431. Data showed that the intracellular content from four strains, i.e., Lactobacillus fermentum J10, Lactobacillus pentosus J24 and J26, and Lactobacillus pentosus J27, showed higher (P < 0.05) antioxidant capacity in most methods used. Thereafter, the intracellular content of such pre-selected strains was able to prevent the disturbance of the antioxidant system of human erythrocytes exposed to acrylamide, thereby reducing cell disruption and eryptosis development (P < 0.05). Additionally, the degree of oxidative stress in erythrocytes exposed to acrylamide was significantly (P < 0.05) reduced to levels similar to the basal conditions when the intracellular content of Lact. fermentum J10, Lact. pentosus J27, and Lact. paracasei 431 were employed. Hence, our findings suggest that the intracellular contents of specific Lactobacillus strains represent a potential source of metabolites with antioxidant properties that may help reduce the oxidative stress induced by acrylamide in human erythrocytes.

Asunto(s)

Acrilamida/farmacología , Antioxidantes/farmacología , Mezclas Complejas/farmacología , Lacticaseibacillus casei/química , Lacticaseibacillus paracasei/química , Lactobacillus pentosus/química , Limosilactobacillus fermentum/química , Acrilamida/antagonistas & inhibidores , Antioxidantes/química , Catalasa/metabolismo , Células Cultivadas , Cromanos/farmacología , Mezclas Complejas/química , Eritrocitos/citología , Eritrocitos/efectos de los fármacos , Eritrocitos/metabolismo , Glutatión/metabolismo , Glutatión Peroxidasa/metabolismo , Hemólisis/efectos de los fármacos , Humanos , Lacticaseibacillus casei/metabolismo , Limosilactobacillus fermentum/metabolismo , Lacticaseibacillus paracasei/metabolismo , Lactobacillus pentosus/metabolismo , Malondialdehído/antagonistas & inhibidores , Malondialdehído/metabolismo , Oxidación-Reducción , Estrés Oxidativo , Probióticos/química , Superóxido Dismutasa/metabolismo

RESUMEN

Under optimized conditions, the lactic acid bacterium Lactobacillus fermentum Lf2 secretes up to 2 gL-1 of a mixture of polysaccharides into the fermentation medium when grown on sucrose. Earlier studies had shown that the mixture is biologically active and work was undertaken to characterise the polysaccharides. Preparative size exclusion chromatography was used to separate a high molecular mass ß-glucan (weight average mass of 1.23 × 106 gmol-1) from two medium molecular mass polysaccharides (weight average mass of 8.8 × 104 gmol-1). Under optimized growth conditions, the medium molecular mass polysaccharides accounted for more than 75% of the mixture by weight. Monomer, linkage analysis and NMR spectroscopy of the medium molecular mass polysaccharides, and material isolated after their Smith degradation, was used to identify the structure of the component polysaccharides. The mixture contains two novel polysaccharides. The first has a main chain of ß-1,6-linked galactofuranoses which is non-stoichiometrically 2-O-glucosylated. The degree of substitution at the 2-position, with α-D-Glcp, depends on the fermentation conditions; under optimized conditions greater than 80% 2-O-α-D-glucosylation was observed. The second polysaccharide is a heteroglycan with four monosaccharides in the repeat unit: residual signals in the NMR suggest that the sample also contains trace amounts (<3%) of cell wall polysaccharides.

Asunto(s)

Limosilactobacillus fermentum/crecimiento & desarrollo , Polisacáridos Bacterianos/química , beta-Glucanos/química , Secuencia de Carbohidratos , Fermentación , Limosilactobacillus fermentum/química , Peso Molecular

RESUMEN

The study of microbial communities associated with spontaneous fermentation of agave juice for tequila production is required to develop starter cultures that improve both yield and quality of the final product. Quantification by HPLC of primary metabolites produced during the fermentations was determined. A polyphasic approach using plate count, isolation and identification of microorganisms, denaturing gradient gel electrophoresis and next generation sequencing was carried out to describe the diversity and dynamics of yeasts and bacteria during small-scale spontaneous fermentations of agave juice from two-year samplings. High heterogeneity in microbial populations and fermentation parameters were observed, with bacteria showing higher diversity than yeast. The core microorganisms identified were Saccharomyces cerevisiae and Lactobacillus fermentum. Practices in tequila production changed during the two-year period, which affected microbial community structure and the time to end fermentation. Bacterial growth and concomitant lactic acid production were associated with low ethanol production, thus bacteria could be defined as contaminants in tequila fermentation and efforts to control them should be implemented.

Asunto(s)

Bebidas Alcohólicas/microbiología , Bacterias/metabolismo , Levaduras/aislamiento & purificación , Agave/química , Agave/microbiología , Bebidas Alcohólicas/análisis , Bacterias/química , Bacterias/genética , Bacterias/aislamiento & purificación , Biodiversidad , Etanol/metabolismo , Fermentación , Cinética , Limosilactobacillus fermentum/química , Limosilactobacillus fermentum/metabolismo , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/metabolismo , Levaduras/química , Levaduras/genética , Levaduras/metabolismo

RESUMEN

The long-term effects of three dietary probiotics on rainbow trout during grow-out (mean body weight = 250 ±â€¯50 g) were investigated by feeding for 130 days on eight diet treatments supplemented with Lactobacillus buchneri, L. fermentum and Saccharomyces cerevisiae at 107 CFU/g, singularly or in combination. Fish samples were taken for biochemical and immunological analysis in addition to growth performance indices at days 30 and 130 of the experiment. The expression levels of TNF-α and IL-1ß genes were also measured at day 130. A positive effect on food conversion was observed in rainbow trout with dietary inclusion of S. cerevisiae (P < 0.05) over 130 days. Also, the total number of white blood cells and their differential count (blood neutrophils, lymphocytes and monocytes), as well as respiratory burst activity were all significantly affected by different treatments at 130 days (P < 0.05). Moreover, at 130 days there was a significant increase in the expression of TNF-α and IL-1ß in yeast present treatment compared to the control group (P < 0.05), but no significant difference in the combined probiotic treatments from control group. Yeast and L. buchneri showed a contrary effect on the immune gene expression regulation. Serum cholesterol was significantly lower in all treatments receiving yeast as a dietary probiotic, either alone or in combination with other probiotics. However, none of the probiotic treatments had a significant effect on trout growth performance, or total protein, albumin, globulin, triglyceride and the red blood cell count after 30 or 130 days. Overall, the results suggest that inclusion of a single dietary probiotic, especially S. cerevisiae, in rainbow trout during grow-out has a greater positive effect than combinations of probiotics on the immune system.

Asunto(s)

Lactobacillus/química , Limosilactobacillus fermentum/química , Oncorhynchus mykiss/genética , Oncorhynchus mykiss/inmunología , Probióticos/farmacología , Saccharomyces cerevisiae/química , Alimentación Animal/análisis , Animales , Citocinas/genética , Citocinas/metabolismo , Dieta/veterinaria , Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Expresión Génica , Inmunidad Innata , Oncorhynchus mykiss/sangre , Distribución Aleatoria

RESUMEN

The present study utilizes lactobacilli strains having the potential to accumulate a significant amount of Zinc (Zn) in their biomass and ability to deliver the same mineral in a highly bioavailable form. A human origin Lactobacillus fermentum SR4 and Lactobacillus rhamnosus GG (LGG) were studied for their ability to accumulate Zn by growing them in the medium containing Zn salt. Further, Zn enriched cell lysates were prepared by Ultrasonication, as an organic Zn source. Various functional groups involved in bacterial Zn binding were identified by FT-IR spectroscopy and elemental Zn in bio-chelated cell lysate complex was confirmed by SEM and Energy Dispersive X-ray Spectrometry (EDX). Experimental data demonstrated a significantly higher (P < 0.05) bioavailability of Zn chelated by SR4 followed by LGG i.e., 57% and 48%, as compared to the commercially available inorganic (ZnSo4) and even organic (Zinc gluconate) forms tested which has 15.6% and 21.7% respectively.

Asunto(s)

Lacticaseibacillus rhamnosus/química , Limosilactobacillus fermentum/química , Zinc/metabolismo , Disponibilidad Biológica , Células CACO-2 , Colon/metabolismo , Colon/microbiología , Humanos , Microscopía Electrónica de Rastreo , Espectroscopía Infrarroja por Transformada de Fourier , Zinc/análisis

RESUMEN

This study investigates the possible effects of using Lactobacillus fermentum (LF) and/or ferulic acid (FA) in common carp (Cyprinus carpio) on some immunological parameters as well as resistance against Aeromonas hydrophila. Four diets were prepared including control diet and three diets supplemented with LF (108 CFU/g), FA (100 mg kg-1) or LF + FA (108 CFU/g + 100 mg kg-1). After 8 weeks, fish fed LF or/and FA had significantly higher final body weight, weight gain, and specific growth rate when compared to control group (P < 0.05). The feed conversion ratio of fish fed LF or/and FA were noticeably lower than control (P < 0.05). No alterations were observed in case of haematological parameters except red blood cells (RBCs), white blood cells (WBCs), hemoglobin (Hb), and hematocrit (HCT) which were significantly (P < 0.05) increased in fish fed FA or those fed both LF and FA. Also, the WBCs of fish treated with LF or/and FA were noticeably higher than control (P < 0.05). Feeding on LF and FA notably increased the serum total protein and albumin levels (P < 0.05). The serum respiratory burst and lysozyme activity were also enhanced (P < 0.05) in fish fed both LF or/and FA. In addition, evaluation of the serum antioxidant enzymes (catalase, glutathione peroxidase (GPX), and superoxide dismutase (SOD)) activity showed significant (P < 0.05) increase in fish fed FA or both LF and FA as compared to the control. Fish fed LF and FA supplemented diet had highest survival rate after experimental challenge with pathogenic A. hydrophila. The obtained results revealed that LF and/or FA can be used as beneficial feed additive to improve the immune responses and disease resistance in early stages of common carp culture.

Asunto(s)

Antioxidantes/metabolismo , Carpas/inmunología , Ácidos Cumáricos/metabolismo , Resistencia a la Enfermedad/inmunología , Enfermedades de los Peces/inmunología , Limosilactobacillus fermentum/química , Aeromonas hydrophila/fisiología , Alimentación Animal/análisis , Animales , Ácidos Cumáricos/administración & dosificación , Dieta/veterinaria , Suplementos Dietéticos/análisis , Infecciones por Bacterias Gramnegativas/inmunología , Probióticos/farmacología , Distribución Aleatoria

RESUMEN

A cell-bound exopolysaccharide (c-EPS) from Lactobacillus fermentum S1 was isolated and purified to near homogeneity by anion exchange and gel filtration chromatography. The c-EPS is a homogeneous heteropolysaccharide with an average molecular weight of 7.19 × 105 Da and comprises mainly mannose, rhamnose, glucose, and galactose. Fourier transform infrared spectroscopy spectrum of the c-EPS exhibited typical characteristic absorption peaks of polysaccharides. Methylation and NMR analyses showed that the c-EPS had a backbone of α-D-Galp-(1 → 3), α-L-Rhap-(1 → 2), α-D-Glcp-(1 → 3), ß-D-Galp-(1 → 3), ß-D-Glclp-(1 → 2), and ß-L-Rhap-(1 → 3,4) residues, terminated with α-D-Manp-(1 → residue. The advanced structure study indicated the c-EPS not to have a triple-helical conformation, while the microstructural study revealed a hollow porous structure for c-EPS. Further, the thermal analysis showed that the degradation temperature for the c-EPS was 288.0 °C; its peak temperature was 89.4 °C with an enthalpy value of 273.1 J/g. Moreover, the c-EPS exhibited potent DPPH, hydroxyl, and ABTS+ radicals scavenging activities, as well as FRAP in a dose-dependent manner, which could significantly enhance the T-AOC and SOD activity and reduce MDA level in Caenorhabditis elegans. Therefore, this c-EPS could be utilized as a promising natural antioxidant for application in functional foods.

Asunto(s)

Antioxidantes/química , Antioxidantes/farmacología , Limosilactobacillus fermentum/química , Polisacáridos Bacterianos/química , Polisacáridos Bacterianos/farmacología , Antioxidantes/aislamiento & purificación , Cápsulas Bacterianas/química , Fenómenos Químicos , Espectroscopía de Resonancia Magnética , Metilación , Peso Molecular , Polisacáridos Bacterianos/aislamiento & purificación , Análisis Espectral , Termogravimetría

RESUMEN

Rheological properties and supramolecular structure of the exopolysaccharide (EPS) secreted by Lactobacillus fermentum MTCC 25067 were investigated. The critical concentration representing the lower-limit of the semi-dilute regime was estimated to be 0.71 g/L from the concentration dependence of zero-shear specific viscosity. The storage modulus (G') of a 20 g/L EPS solution was greater than the loss modulus (G″) at 0.1-25 Hz. Approximately linear increases in G' and G″ determined at a frequency of 1 Hz and a strain of 0.01 during cooling from 80 to 25 °C were an indication that the EPS did not undergo thermally-induced cooperative conformational transitions typical of gelling polysaccharides. Atomic force microscopy images revealed that EPS molecules were not completely dissociated into individual molecules in an aqueous solution but remained to form three-dimensional networks. The gel-like dynamic viscoelasticity of the 20 g/L EPS solution was thus attributed to the existence of supramolecular assemblies resulting from significant degrees of intermolecular association of the EPS in the solution.

Asunto(s)

Limosilactobacillus fermentum/química , Polisacáridos Bacterianos/química , Sustancias Viscoelásticas/química , Elasticidad , Peso Molecular , Polisacáridos Bacterianos/aislamiento & purificación , Reología , Sustancias Viscoelásticas/aislamiento & purificación , Viscosidad

RESUMEN

When grown in a semi-defined medium, L. fermentum Lf2 synthesizes significant quantities (∼2 g/L) of two exopolysaccharides (EPS). The two EPS were separated by preparative size exclusion chromatography to give a high molecular mass ß-glucan (1.23 × 106 Da) and a medium molecular mass heteroglycan (8.8 × 104 Da). The structure of the high molecular mass ß-glucan was determined using a combination of NMR spectroscopy, monomer and linkage analysis. The EPS has the following structure: The immunomodulatory activity of the high molecular mass EPS was studied in peripheral blood mononuclear cells (PBMC). Exposure of PBMC to an aqueous solution of the EPS for 24 h led to increased cell proliferation, changes in expression of the cytokines CD14 and TLR2, and to an increase in production of TNF-α compared to controls. In contrast, when cells that had been treated with EPS for 24 h and from which the EPS had been removed, were subsequently exposed to the bacterial antigen LPS very low levels of TNF-α production were observed. This result indicates that the EPS imparts immunotolerance in PBMC. An ability to modulate the release of the proinflammatory mediators, such as TNF-α, is an important goal in the development of therapies for the treatment of diseases, such as Crohn's disease and ulcerative colitis, associated with excessive release of inflammatory mediators.

Asunto(s)

Factores Inmunológicos/química , Factores Inmunológicos/farmacología , Limosilactobacillus fermentum/química , beta-Glucanos/química , beta-Glucanos/farmacología , Humanos , Factores Inmunológicos/aislamiento & purificación , Leucocitos Mononucleares/efectos de los fármacos , Leucocitos Mononucleares/inmunología , Leucocitos Mononucleares/metabolismo , Receptores de Lipopolisacáridos/metabolismo , Receptor Toll-Like 2/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , beta-Glucanos/aislamiento & purificación

RESUMEN

Heavy metals naturally occur in the environment and are causing great concern all around the world. Accumulation of heavy metals in fish tissues can lead to serious adverse effects in humans when consumed in the amounts exceeding the safe consumption levels. In this study, Lactobacillus fermentum 1744 (ATCC 14931) and lactulose were used in the fish diet in order to investigate their effects on growth performance, intestinal villous morphology, and heavy metals residues. Fishes were randomly allocated into three replicates of five different treatments. The control group received the basal diet, while the experimental groups were fed on the basal diet supplemented with encapsulated and lyophillized probiotic, lactulose (prebiotic) and L. fermentum, and lactulose as synbiotic. All the groups were fed three times daily for a period of 56 days. At the end of growth period, 10 fish per replicate were randomly collected in order to take the samples of the fillet, gills, and liver. Results showed that the encapsulated L. fermentum plus lactulose improve growth performance and exclude absorption and accumulation of heavy metals in rainbow trout liver and gills. The villous height were increased in all the samples except the group 2 fed on the lactulose (p < 0.05).

Asunto(s)

Lactulosa/metabolismo , Metales Pesados/metabolismo , Oncorhynchus mykiss/crecimiento & desarrollo , Oncorhynchus mykiss/metabolismo , Probióticos/administración & dosificación , Oligoelementos/metabolismo , Alimentación Animal/análisis , Alimentación Animal/microbiología , Animales , Composición de Medicamentos , Branquias/química , Branquias/metabolismo , Limosilactobacillus fermentum/química , Limosilactobacillus fermentum/fisiología , Hígado/química , Hígado/metabolismo , Metales Pesados/análisis , Músculo Esquelético/química , Músculo Esquelético/metabolismo , Oncorhynchus mykiss/microbiología , Probióticos/química , Oligoelementos/análisis

RESUMEN

Clinical and animal studies have demonstrated beneficial effects of early consumption of dairy lipids and a probiotic, Lactobacillus fermentum (Lf), on infant gut physiology. The objective of this study was to investigate their long-term effects on gut microbiota and host entero-insular axis and metabolism. Piglets were suckled with a milk formula containing only plant lipids (PL), a half-half mixture of plant lipids and dairy lipids (DL), or this mixture supplemented with Lf (DL + Lf). They were weaned on a standard diet and challenged with a high-energy diet until postnatal day 140. DL and DL + Lf modulated gut microbiota composition and metabolism, increasing abundance of several Clostridia genera. Moreover, DL + Lf specifically decreased the faecal content of 2-oxoglutarate and lysine compared to PL and 5-aminovalerate compared to PL and DL. It also increased short-chain fatty acid concentrations like propionate compared to DL. Furthermore, DL + Lf had a beneficial effect on the endocrine function, enhancing caecal GLP-1 and GLP-1 meal-stimulated secretion. Correlations highlighted the consistent relationship between microbiota and gut physiology. Together, our results evidence a beneficial programming effect of DL + Lf in infant formula composition on faecal microbiota and entero-insular axis function.

Asunto(s)

Microbioma Gastrointestinal/efectos de los fármacos , Fórmulas Infantiles/química , Lípidos/administración & dosificación , Probióticos/administración & dosificación , Animales , Suplementos Dietéticos , Heces/microbiología , Humanos , Lactante , Limosilactobacillus fermentum/química , Lípidos/química , Leche/química , Probióticos/química , Porcinos , Porcinos Enanos

RESUMEN

Lactobacillus species possesses surface exposed Mucin Binding Protein (MucBP) which plays a role in adhesion to gastrointestinal mucin. MucBP contains one or more mucin binding domain (MBD), the functionality of which has yet not been characterized thoroughly. Here, we have characterized a 93-amino acid MBD (MBD93) of MucBP (LAF_0673) from Lactobacillus fermentum. Multiple sequence alignment of L. fermentum MBD93 exhibited ∼60% sequence homology with MBDs from other Lactobacillus species. Further, we cloned, expressed and purified MBD93 from Escherichia coli as N-terminal histidine-tagged protein (6X His-MBD93). The purified MBD93 was able to bind to mucin and showed strong affinity towards the terminally expressed mucin glycans viz. N-acetylgalactosamine (GalNAc), N-acetylglucosamine (GlcNAc), Galactose (Gal), and Sialic acid (N-acetylneuraminic acid; Neu5Ac). In silico experiments further confirmed the interaction between homology modeled MBD93 to mucin glycans through hydrogen-bonding with its surface amino acid residues Ser57, Pro58, Ile60, Tyr63 and Ala65. We also have demonstrated that MBD93 was able to inhibit the adhesion of enteric pathogens, including E. coli, Salmonella Paratyphi A, Shigella sonnei and Proteus vulgaris to mucin. Our results suggested that L. fermentum MBD93 is a functionally sufficient unit to act as an adhesin and to protect from invading enteric pathogens.

Asunto(s)

Adhesinas Bacterianas , Adhesión Bacteriana/efectos de los fármacos , Limosilactobacillus fermentum , Mucinas/metabolismo , Adhesinas Bacterianas/química , Adhesinas Bacterianas/genética , Adhesinas Bacterianas/metabolismo , Adhesinas Bacterianas/farmacología , Animales , Escherichia coli Enteropatógena/metabolismo , Escherichia coli Enteropatógena/patogenicidad , Limosilactobacillus fermentum/química , Limosilactobacillus fermentum/genética , Limosilactobacillus fermentum/metabolismo , Dominios Proteicos , Proteus vulgaris/metabolismo , Proteus vulgaris/patogenicidad , Salmonella paratyphi A/metabolismo , Salmonella paratyphi A/patogenicidad , Shigella sonnei/metabolismo , Shigella sonnei/patogenicidad , Porcinos

RESUMEN

One potent lactic acid bacterial strain C14 with strong antifungal activity was isolated from homemade curd. Based on morphological as well as biochemical characters and 16S rDNA sequence homology the strain was identified as Lactobacillus fermentum. It displayed a wide antimicrobial spectrum against both Gram-positive and Gram-negative pathogenic bacteria, and also against number of food spoilage, plant and human pathogenic fungi. The cell free supernatant (CFS) of the strain C14 was also effective against the fungi tested. Inhibition of radial growth of Penicillium digitatum, Trichophyton rubrum and Mucor sp. was noticed in the presence of CFS of C14 even at low concentration (1%). More than 94.3 ± 1.6% and 91.5 ± 2.2% inhibition of conidial germination of P. digitatum and Mucor sp. were noticed in the presence of 10-fold-concentrated CFS of C14. Massive deformation of the fungal mycelia was observed by SEM studies, and losses of cellular proteins and DNA are also evident upon its treatment with C14. HPLC analysis revealed the presence of phenyl lactic acid, lactic acid along with some unidentified compounds in the antifungal extract. Challenge experiment showed immense potential of the strain C14 in preventing the spoilage of bread samples caused by Mucor sp. and Bacillus subtilis. The bread samples remained fresh upto 25 days even after inoculation with Mucor sp. (3.7 × 104 spores /ml) and B. subtilis (4.6 × 104 CFU /ml). Along with the antifungal properties, the isolated lactic acid bacterial strain also showed very good antioxidant activities. Unchanged level of liver enzymes serum glutamic pyruvic transaminase and serum glutamic oxaloacetic transaminase in albino mice upon feeding with C14 also suggested non-toxic nature of the bacterial isolate.

Asunto(s)

Antiinfecciosos/farmacología , Antibiosis , Conservantes de Alimentos/farmacología , Lactatos/farmacología , Ácido Láctico/farmacología , Limosilactobacillus fermentum/química , Leche/microbiología , Alanina Transaminasa/metabolismo , Animales , Antiinfecciosos/aislamiento & purificación , Aspartato Aminotransferasas/sangre , Pan , Fermentación , Conservantes de Alimentos/aislamiento & purificación , Almacenamiento de Alimentos/métodos , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Gramnegativas/crecimiento & desarrollo , Bacterias Grampositivas/efectos de los fármacos , Bacterias Grampositivas/crecimiento & desarrollo , Humanos , Lactatos/aislamiento & purificación , Ácido Láctico/aislamiento & purificación , Limosilactobacillus fermentum/aislamiento & purificación , Masculino , Ratones , Mucor/efectos de los fármacos , Mucor/crecimiento & desarrollo , Micelio/efectos de los fármacos , Micelio/crecimiento & desarrollo , Penicillium/efectos de los fármacos , Penicillium/crecimiento & desarrollo , Trichophyton/efectos de los fármacos , Trichophyton/crecimiento & desarrollo

RESUMEN

The use of intestinal probiotic bacteria is very common in the food industry and has been the focus of the majority of research in this field. Yet in recent years, research on extraintestinal microorganisms has greatly increased due to their well-known potential as probiotics. Thus, we studied a strain of Lactobacillus fermentum (TCUESC01) extracted from fermenting cocoa. First, we examined the impact of pH on the growth of this strain and studied its survival under conditions similar to those of the human gastrointestinal tract. L. fermentum TCUESC01 demonstrated resistance to conditions mimicking the human stomach and intestines and grew well between pH 5 and pH 7. Next, we subjected L. fermentum TCUESC01 to storage at 4°C in a milk solution and found that it survived well for 28 days. Lastly, we measured the susceptibility of this strain to numerous antibiotics and its tendency to autoaggregate. L. fermentum TCUESC01 showed significant autoaggregation, as well as susceptibility to the majority of antibiotics tested. Overall, our findings support the potential use of this extraintestinal bacterium as a dietary probiotic.

Asunto(s)

Fermentación , Microbiología de Alimentos , Limosilactobacillus fermentum/metabolismo , Probióticos/metabolismo , Animales , Cacao/química , Cacao/microbiología , Industria de Alimentos , Humanos , Limosilactobacillus fermentum/química , Leche/química , Leche/metabolismo , Probióticos/química

RESUMEN

We have taken a vital step towards understanding why probiotic bacteria increase iron absorption in the gastrointestinal tract. We show here that Lactobacillus fermentum, one of the main probiotics of the microbiota, exhibits an extraordinary ferric-reducing activity. This activity is predominantly due to an excreted molecule: p-hydroxyphenyllactic acid (HPLA). Reduction of Fe(III) to Fe(II) is essential for iron absorption in the gastrointestinal tract. By reducing Fe(III), HPLA boosts Fe(II) absorption through the DMT1 channels of enterocytes. An in vitro experiment tested and confirmed this hypothesis. This discovery opens new avenues for the treatment of iron deficiency in humans, one of the most common and widespread nutritional disorders in the world.

Asunto(s)

Hierro/metabolismo , Limosilactobacillus fermentum/química , Probióticos/metabolismo , Fermentación , Humanos