Academic literature on the topic 'Bifidobacterium pseudolongum'

Fructooligosaccharides (FOS) are a well-known class of prebiotic and are considered to selectively stimulate the growth of bifidobacteria in the gut. Previous studies focused on the growth stimulation of Bifidobacterium, but they did not further investigate the bifidobacterial composition and the specific species that were stimulated. In this study, mice were fed with FOS in different doses for four weeks and the composition of fecal microbiota, in particular Bifidobacterium, was analyzed by sequencing the V3–V4 region and the groEL gene on the MiSeq platform, respectively. In the high-dose group, the relative abundance of Actinobacteria was significantly increased, which was mainly contributed by Bifidobacterium. At the genus level, the relative abundances of Blautia and Coprococcus were also significantly increased. Through the groEL sequencing, 14 species of Bifidobacterium were identified, among which B. pseudolongum was most abundant. After FOS treatment, B. pseudolongum became almost the sole bifidobacterial species (>95%). B. pseudolongum strains were isolated and demonstrated their ability to metabolize FOS by high performance liquid chromatography (HPLC). Therefore, we inferred that FOS significantly stimulated the growth of B. pseudolongum in mice. Further investigations are needed to reveal the mechanism of selectiveness between FOS and B. pseudolongum, which would aid our understanding of the basic principles between dietary carbohydrates and host health.

ABSTRACT In the luminal contents of metronidazole-treated rats, there was a dominant Bifidobacterium species. A strain has been isolated, its 16S rRNA gene has been sequenced, and the strain has been named Bifidobacterium pseudolongum strain Patronus. In this study, using an experimental model of healthy rats, the effects of metronidazole treatment and B. pseudolongum strain Patronus administration on the luminal and mucosa-associated microbiota and on gut oxidation processes were investigated. Metronidazole treatment and the daily gavage of rats with B. pseudolongum strain Patronus increased the numbers of bifidobacteria in cecal contents and in cecal mucosa-associated microbiota compared with those in control rats. Metronidazole reduced the colonic oxidative damage to proteins. This is the first evidence that B. pseudolongum strain Patronus exerts an effect on a biomarker of oxidative damage by reducing the susceptibility to oxidation of proteins in the colon and the small bowel. Antioxidant effects of metronidazole could be linked to the bifidobacterial increase but also to other bacterial modifications.

Background: Although genomic features of various bifidobacterial species have received much attention in the past decade, information on Bifidobacterium pseudolongum was limited. In this study, we retrieved 887 publicly available genomes of bifidobacterial species, and tried to elucidate phylogenetic and potential functional roles of B. pseudolongum within the Bifidobacterium genus. Results: The results indicated that B. pseudolongum formed a population structure with multiple monophyletic clades, and had established associations with different types of mammals. The abundance of B. pseudolongum was inversely correlated with that of the harmful gut bacterial taxa. We also found that B. pseudolongum showed a strictly host-adapted lifestyle with a relatively smaller genome size, and higher intra-species genetic diversity in comparison with the other tested bifidobacterial species. For functional aspects, B. pseudolongum showed paucity of specific metabolic functions, and enrichment of specific enzymes degrading complex plant carbohydrates and host glycans. In addition, B. pseudolongum possessed a unique signature of probiotic effector molecules compared with the other tested bifidobacterial species. The investigation on intra-species evolution of B. pseudolongum indicated a clear evolution trajectory in which considerable clade-specific genes, and variation on genomic diversity by clade were observed. Conclusions: These findings provide valuable information for explaining the host adaptability of B. pseudolongum, its evolutionary role, as well as its potential probiotic effects.

Bifidobacteria were isolated from 122 of 145 samples of animal feces (from cattle, swine, sheep, goats, horses, rabbits, chickens, geese, and pigeons) from farms in France and Austria and from 92 of 955 production and processing chain samples of beef and pork (obtained at slaughter, cutting, and retail). Bacterial strains were identified to species by phenotypic numerical classification based on API 50CH and ID 32A tests and DNA-DNA hybridization. Bifidobacterium pseudolongum was present in 81% (99 of 122 samples) of all Bifidobacterium-positive fecal samples and predominated in samples from all animal species except those from swine from Austria. In these Austrian swine samples, the majority of strains were identified as Bifidobacterium thermophilum (78%), followed by B. pseudolongum (48%). The distribution of B. thermophilum and B. pseudolongum differed significantly between Austrian swine and cattle samples such as those collected along beef and pork production and processing chains. Bifidobacterium animalis was isolated from swine feces, and Bifidobacterium ruminantium was isolated from cow dung. Six fecal isolates (from cattle, swine, rabbits, goats, and horses) were identified as belonging to Bifidobacterium species of predominantly human origin: B. adolescentis, B. bifidum, and B. catenulatum. Only one other species, Bifidobacterium choerinum, was detected with low frequency in a pork processing chain. B. pseudolongum subsp. pseudolongum was predominant in pig feces, whereas B. pseudolongum subsp. globosum was predominant in feces from other animal species. Four strains closely related to both subspecies (58 to 61% DNA reassociation) formed a distinct genomic group. PCR techniques, which are more rapid and sensitive than culture-based methods, could be used to detect directly B. pseudolongum and B. thermophilum as indicators of fecal contamination along the meat processing chain.

ABSTRACT Although the health-promoting roles of bifidobacteria are widely accepted, the diversity of bifidobacteria among the human intestinal microbiota is still poorly understood. We performed a census of bifidobacterial populations from human intestinal mucosal and fecal samples by plating them on selective medium, coupled with molecular analysis of selected rRNA gene sequences (16S rRNA gene and internally transcribed spacer [ITS] 16S-23S spacer sequences) of isolated colonies. A total of 900 isolates were collected, of which 704 were shown to belong to bifidobacteria. Analyses showed that the culturable bifidobacterial population from intestinal and fecal samples include six main phylogenetic taxa, i.e., Bifidobacterium longum, Bifidobacterium pseudocatenulatum, Bifidobacterium adolescentis, Bifidobacterium pseudolongum, Bifidobacterium breve, and Bifidobacterium bifidum, and two species mostly detected in fecal samples, i.e., Bifidobacterium dentium and Bifidobacterium animalis subp. lactis. Analysis of bifidobacterial distribution based on age of the subject revealed that certain identified bifidobacterial species were exclusively present in the adult human gut microbiota whereas others were found to be widely distributed. We encountered significant intersubject variability and composition differences between fecal and mucosa-adherent bifidobacterial communities. In contrast, a modest diversification of bifidobacterial populations was noticed between different intestinal regions within the same individual (intrasubject variability). Notably, a small number of bifidobacterial isolates were shown to display a wide ecological distribution, thus suggesting that they possess a broad colonization capacity.

A fructose-6-phosphate phosphoketolase-positive strain (GSD1FST) was isolated from a faecal sample of a 3 weeks old German Shepherd dog. The closest related taxa to isolate GSD1FST based on results from the EZBioCloud database were Bifidobacterium animalis subsp. animalis ATCC 25527T, Bifidobacterium animalis subsp. lactis DSM 10140T and Bifidobacterium anseris LMG 30189T, belonging to the Bifidobacterium pseudolongum phylogenetic group. The resulting 16S rRNA gene identities (compared length of 1454 nucleotides) towards these taxa were 97.30, 97.23 and 97.09 %, respectively. The pairwise similarities of strain GSD1FST using argS, atpA, fusA, hsp60, pyrG, rpsC, thrS and xfp gene fragments to all valid representatives of the B. pseudolongum phylogenetic group were in the concatenated range of 83.08–88.34 %. Phylogenomic analysis based on whole-genome methods such as average nucleotide identity revealed that bifidobacterial strain GSD1FST exhibits close phylogenetic relatedness (88.17 %) to Bifidobacetrium cuniculi LMG 10738T. Genotypic characteristics and phylogenetic analyses based on nine molecular markers, as well as genomic and comparative phenotypic analyses, clearly proved that the evaluated strain should be considered as representing a novel species within the B. pseudolongum phylogenetic group named as Bifidobacterium canis sp. nov. (GSD1FST=DSM 105923T=LMG 30345T=CCM 8806T).

Fructooligosaccharides (FOS) are considered prebiotics and have been proven to selectively promote the growth of Bifidobacterium in the gut. This study aimed to clarify the effects of FOS intake on the composition of luminal and mucosal microbiota in mice. Briefly, mice were fed a 0% or 25% FOS (w/w)-supplemented diet for four weeks, and the composition of luminal and mucosal microbiota, especially the Bifidobacterium, was analyzed by sequencing the V3–V4 region of 16S rRNA and groEL gene, respectively. After FOS intervention, there were significant increases in the total and wall weights of the cecum and the amount of total short-chain fatty acids (SCFAs) in the cecal contents of the mice. At the phylum level, the results showed a significant increase in the relative abundance of Actinobacteria in the contents and mucosa from the cecum to the distal colon in the FOS group. Besides Bifidobacterium, a significant increase was observed in the relative abundance of Coprococcus in all samples at the genus level, which may be partially related to the increase in butyric acid levels in the luminal contents. Furthermore, groEL sequencing revealed that Bifidobacterium pseudolongum was almost the sole bifidobacterial species in the luminal contents (>98%) and mucosa (>89%). These results indicated that FOS can selectively promote B. pseudolongum proliferation in the intestine, either in the lumen or the mucosa from the cecum to the distal colon. Further studies are required to reveal the competitive advantage of B. pseudolongum over other FOS-metabolizing bacteria and the response mechanisms of B. pseudolongum to FOS.

Partial RNA polymerase β-subunit gene (rpoB) sequences (315 bp) were determined and used to differentiate the type strains of 23 species of the genus Bifidobacterium. The sequences were compared with those of the partial hsp60 (604 bp) and 16S rRNA genes (1475 or 1495 bp). The rpoB gene sequences showed nucleotide sequence similarities ranging from 84.1 % to 99.0 %, while the similarities of the hsp60 sequences ranged from 78.5 % to 99.7 % and the 16S rRNA gene sequence similarities ranged from 89.4 % to 99.2 %. The phylogenetic trees constructed from the sequences of these three genes showed similar clustering patterns, with the exception of several species. The Bifidobacterium catenulatum–Bifidobacterium pseudocatenulatum, Bifidobacterium pseudolongum subsp. pseudolongum–Bifidobacterium pseudolongum subsp. globosum and Bifidobacterium gallinarum–Bifidobacterium pullorum–Bifidobacterium saeculare groups were more clearly differentiated in the partial rpoB and hsp60 gene sequence trees than they were in the 16S rRNA gene tree. Based on sequence similarities and tree topologies, the newly determined rpoB gene sequences are suitable molecular markers for the differentiation of species of the genus Bifidobacterium and support various other molecular tools used to determine the relationships among species of this genus.

ABSTRACT This study initially involved the isolation of a number of bifidobacteria from either the lumen or the epithelium of a porcine cecum. A total of 160 isolates were selected at random on MRS plates containing cysteine hydrochloride (0.5 g/liter) and mupirocin (50 mg/liter). All were identified as bifidobacteria based on fructose-6-phosphate phosphoketolase activity. Following genomic digestion with the restriction enzyme XbaI and pulsed-field gel electrophoresis (PFGE), the isolates produced 15 distinct macro-restriction patterns. Several of the PFGE patterns differed by only 1, 2, or 3 DNA fragments and were grouped as related patterns into seven PFGE types, termed A through G. The related patterns appeared to show genomic plasticity within the isolates arising from chromosomal mutations or possibly horizontal transfer of plasmids. The relative frequency of each PFGE type was maintained within each cecal sample, with PFGE type E representing approximately 50% of the isolates. Randomly amplified polymorphic DNA PCR, cell morphology, whole-cell protein profiling, 16S ribosomal DNA sequencing, and DNA-DNA hybridization were used to determine if the seven apparently unrelated PFGE types represented genetically distinct isolates. Four groups were identified: PFGE types A, C/D/G, B/E, and F, and these appeared to represent Bifidobacterium minimum, Bifidobacterium pseudolongum subsp. pseudolongum, and Bifidobacterium pseudolongum subsp. globosum and two new species, respectively. The data demonstrate the presence of considerable genomic diversity within a relatively simple bifidobacteria population, consisting of 15 distinct strains representing four groups, which was maintained throughout the porcine cecal contents and epithelial layer.

La maladie d'Alzheimer (MA) est une maladie neurodégénérative associée au vieillissement, constituant un problème de santé publique majeure dans le monde. Il n’y a actuellement aucun traitement efficace ni de moyen reconnu de prévention de cette maladie. La conception de stratégies préventives est donc indispensable pour lutter contre ces maladies. L’alimentation occidentale est particulièrement riche en acides gras ω-6, notamment en acide arachidonique (ARA), converti en nombreux médiateurs de l’inflammation dans le corps. Des travaux antérieurs du laboratoire ont montré qu’un apport alimentaire en ARA sensibilise les souris à la neurotoxicité des oligomères de peptides Aβ, principal agent de la MA. Dans ce travail de thèse, nous avons étudié l’incidence de cet apport alimentaire en ARA sur le microbiote fécal et l’axe microbiote-intestin-cerveau. Nous avons soumis pendant 9 à 12 semaines des cohortes de 15 souris à 3 régimes alimentaires, un régime conventionnel murin (« Sdt-ARA » de 5% de lipides), un régime modérément hyperlipidique de 15% de lipides dont 31,9% d’acide linoléique (« HL-ARA ») et un régime de 15% de lipides dont 25,3% d’acide linoléique et 6,6% d’ARA (« HL+ARA »). L’analyse du microbiote fécal a révélé que le régime « HL-ARA » favorise la prolifération de l’espèce Bifidobacterium pseudolongum dont les activités bénéfiques contre l’inflammation ont été rapportées, et que l’apport d’ARA supprime cette prolifération en favorisant celle du genre Escherichia-Shigella aux effets potentialisateurs de l’inflammation. Les niveaux d’ARNm des cytokines pro-inflammatoires IL-1β et TNFα ont augmenté entre 3 et 11 fois dans le colon des souris nourries avec le régime « HL+ARA ». D’autres médiateurs de l’inflammation colique comme CD40, adiponectine et ICAM-1 ont vu leur expression augmenter par l’enrichissement en ARA tout comme les marqueurs claudine 1 et occludine qui sont des constituants des jonctions serrées. Ces modifications d’expression suggèrent donc des modifications de l’intégrité de la barrière intestinale. L’apport alimentaire d’ARA a également élevé de plus de 10 fois les niveaux d’ARNm du TNFα dans le tissu adipeux mésentérique alors que le retentissement hépatique a été trouvé beaucoup plus modéré. Au niveau cérébral l’apport alimentaire en ARA entraine une augmentation de 1,5-1,8 fois des niveaux d’expression protéique de la GFAP après 9 semaines de régime dans les hippocampes et le cortex alors que ceux du marqueur microglial Iba1 n’a pas été modifié. Nous avons également mis en évidence une diminution des niveaux d’ARNm de l’IL-6 et du TNFα dans le tissu cérébral global.Ces résultats indiquent que l’apport alimentaire en ARA induit une inflammation de bas grade systémique qui pourrait favoriser l’expansion d’un processus de type Alzheimer dans le cerveau si un signal inducteur survient. A ce titre, nous avons également évalué l’impact d’un modèle d’administration per os innovant de D-galactose rapporté comme étant capable d’induire un vieillissement accéléré, une altération des capacités cognitives et l’apparition de plaques amyloïdes dans le cerveau des souris en élevant le stress oxydant. Nous avons également étudié la survie dans le tube digestif de deux souches de Streptococcus thermophilus dont les travaux antérieurs du laboratoire ont montré l’activité anti-inflammatoire in vitro et d’une souche de Lactobacillus plantarum capable de métaboliser les acides gras polyinsaturés ω-6 en acides gras conjugués. Ce travail de thèse a pour perspective d’évaluer la capacité de ces souches probiotiques à lutter contre l’inflammation de bas grade induite par l’apport alimentaire en ARA et le stress oxydant induit par le D-galactose. De nouveaux travaux sont en cours au laboratoire afin d’investiguer plus en détail l’ensemble des processus biologiques en oeuvre dans les différents modèles et de déterminer l’impact des probiotiques sur une administration conjointe de D-galactose et d’un régime riche en ARA
Alzheimer's disease (AD) is a neurodegenerative disease associated with aging, consisting of a major public health problem worldwide. There is currently no effective treatment or established preventions for this disease, highlighting the importance of the design of preventive strategies in the fight against this disease. Western diets are particularly rich in ω-6 fatty acids, especially arachidonic acid (ARA), which are converted into many inflammation mediators in the organism. Previous laboratory results have shown that dietary intake of ARA sensitizes mice to the neurotoxicity of Aβ peptide oligomers, the main agent of AD. In this thesis work, we studied the impact of this dietary intake of ARA on the fecal microbiota and the microbiota-gut-brain axis. For 9 to 12 weeks, three groups of 15 mice have consumed one of these 3 diets : a conventional murine diet (“Sdt-ARA” of 5% lipids), a moderately high-fat diet of 15% lipids including 31.9% of linoleic acid ("HL-ARA"), and a diet of 15% lipids including 25.3% linoleic acid and 6.6% ARA ("HL+ARA").Analysis of the fecal microbiota revealed that the "HL-ARA" diet promotes proliferation of the Bifidobacterium pseudolongum strain, which has been show to possess anti-inflammatory activities. Furthermore, the supply of ARA suppresses this proliferation by favouring Escherichia-Shigella multiplication (with potentiating effects on inflammation). A 3-to-11-fold increase in mRNA levels of the pro-inflammatory cytokines IL-1β and TNFα has been observed in the colon of mice fed with the "HL+ARA" diet. Enrichment of ARA led to an increase of the expression of other mediators of colon inflammation such as CD40, adiponectin, and ICAM-1, as well as the claudin 1 and occludin markers which are components of cellular tight junctions. Therefore, these changes in expression suggest that the integrity of the intestinal barrier has been compromised. Moreover, dietary intake of ARA led to a 10 fold increase in TNFα mRNA levels in mesenteric adipose tissue, while the impact on the liver was found to be much more moderate. At the cerebral level, a 9 weeks food intake of ARA led to a 1.5-1.8-fold increase in the protein level of GFAP in the hippocampus and the cortex, while no changes of the microglial marker Iba1 has not been reported. We also found decreased levels of IL-6 and TNFα mRNA in the global brain tissue.These results indicate that dietary intake of ARA induces low-grade systemic inflammation which may promote the expansion of an Alzheimer's-like process in the brain if an inducing signal occurs. As such, we also evaluated the impact of an innovative oral administration model of D-galactose, which has been described as an aging accelerator compound , leading to impairment of cognitive capacities, and the appearance of amyloid plaques in the mouse brains through elevated oxidative stress. We also studied the survival in the digestive tract of two strains of Streptococcus thermophilus with anti-inflammatory activity in vitro as reported by previous laboratory work, and of a strain of Lactobacillus plantarum capable of metabolizing ω-6 polyunsaturated fatty acids in conjugated fatty acids. This thesis work aims to assess the ability of these probiotic strains to fight against low-grade inflammation induced by dietary intake of ARAs and oxidative stress induced by D-galactose. New work is underway in the laboratory to investigate in more details all the biological processes at work in the different models and to determine the impact of probiotics on a combined administration of D-galactose and an ARA-enriched diet