Bifidobacterium apis sp. nov., isolated from the gut of honeybee (Apis mellifera).

A novel bifidobacterium (designated F753-1T) was isolated from the gut of honeybee (Apis mellifera). Strain F753-1T was characterized using a polyphasic taxonomic approach. Strain F753-1T was phylogenetically related to the type strains of Bifidobacterium mizhiensis, Bifidobacterium asteroides, Bifidobacterium choladohabitans, Bifidobacterium mellis, Bifidobacterium apousia and Bifidobacterium polysaccharolyticum, having 98.4-99.8 % 16S rRNA gene sequence similarities. The phylogenomic tree indicated that strain F753-1T was most closely related to the type strains of B. mellis and B. choladohabitans. Strain F753-1T had the highest average nucleotide identity (94.1-94.5 %) and digital DNA-DNA hybridization (56.3 %) values with B. mellis Bin7NT. Acid production from amygdalin, d-fructose, gentiobiose, d-mannose, maltose, sucrose and d-xylose, activity of α-galactosidase, pyruvate utilization and hydrolysis of hippurate could differentiate strain F753-1T from B. mellis CCUG 66113T and B. choladohabitans JCM 34586T. Based upon the data obtained in the present study, a novel species, Bifidobacterium apis sp. nov., is proposed, and the type strain is F753-1T (=CCTCC AB 2023227T=JCM 36562T=LMG 33388T).

Bifidobacteriaceae Family Diversity in Gut Microbiota of Patients with Renal Failure.

Bifidobacteriaceae family are gut microbiota that exhibit probiotic or health promoting effects on the host. Several studies have suggested that gut microbiota are quantitatively and qualitatively altered in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). The present study aimed to assess the members of Bifidobacteriaceae family in fecal samples of patients with CKD and ESRD and compare them with non-CKD/ESRD patients to find any changes in their counts and diversions in these patients. Twenty fresh fecal samples from patients with CKD/ESRD and twenty from non-CKD/ESRD patients were examined. Whole DNA was extracted from fecal samples and the gut microbiota composition was analyzed by next generation sequencing (NGS). A total of 651 strains were identified from 40 fecal samples, 8 (1.23%) strains of which were identified as family Bifidobacteriaceae. The most abundant species in both control and disease groups were Bifidobacterium adolescentis and Bifidobacterium longum subsp. longum, and the least abundant species in the disease group was Bifidobacterium animalis subsp. lactis. There was no significant difference in the abundance of various species between the disease and control groups (p < 0.05). This study confirms that the members of the Bifidobacteriaceae family are not altered in patients with CKD/ESRD.

Bifidobacterium species associated with breastfeeding produce aromatic lactic acids in the infant gut.

Breastfeeding profoundly shapes the infant gut microbiota, which is critical for early life immune development, and the gut microbiota can impact host physiology in various ways, such as through the production of metabolites. However, few breastmilk-dependent microbial metabolites mediating host-microbiota interactions are currently known. Here, we demonstrate that breastmilk-promoted Bifidobacterium species convert aromatic amino acids (tryptophan, phenylalanine and tyrosine) into their respective aromatic lactic acids (indolelactic acid, phenyllactic acid and 4-hydroxyphenyllactic acid) via a previously unrecognized aromatic lactate dehydrogenase (ALDH). The ability of Bifidobacterium species to convert aromatic amino acids to their lactic acid derivatives was confirmed using monocolonized mice. Longitudinal profiling of the faecal microbiota composition and metabolome of Danish infants (n = 25), from birth until 6 months of age, showed that faecal concentrations of aromatic lactic acids are correlated positively with the abundance of human milk oligosaccharide-degrading Bifidobacterium species containing the ALDH, including Bifidobacterium longum, B. breve and B. bifidum. We further demonstrate that faecal concentrations of Bifidobacterium-derived indolelactic acid are associated with the capacity of these samples to activate in vitro the aryl hydrocarbon receptor (AhR), a receptor important for controlling intestinal homoeostasis and immune responses. Finally, we show that indolelactic acid modulates ex vivo immune responses of human CD4+ T cells and monocytes in a dose-dependent manner by acting as an agonist of both the AhR and hydroxycarboxylic acid receptor 3 (HCA3). Our findings reveal that breastmilk-promoted Bifidobacterium species produce aromatic lactic acids in the gut of infants and suggest that these microbial metabolites may impact immune function in early life.

Characterization of Bifidobacterium apousia sp. nov., Bifidobacterium choladohabitans sp. nov., and Bifidobacterium polysaccharolyticum sp. nov., three novel species of the genus Bifidobacterium from honey bee gut.

Bifidobacterium is one of the dominating bacterial genera in the honey bee gut, and they are the key degrader of diet polysaccharides for the host. Previous genomic analysis shows that they belong to separate phylogenetic clusters and exhibited different functional potentials in hemicellulose digestion. Here, three novel strains from the genus Bifidobacterium were isolated from the guts of the honey bee (Apis mellifera). Phylogenomic analysis showed that the isolates could be grouped into four phylogenetic clusters. The average nucleotide identity values between strains from different clusters are <95%, while strains in Cluster IV belong to the characterized species Bifidobacterium asteroides. Carbohydrate-active enzyme annotation confirmed that the metabolic capacity for carbohydrates varied between clusters of strains. Cells are Gram-positive rods; they grew both anaerobically and in a CO2-enriched atmosphere. All strains grew at a temperature range of 20-42 °C, with optimum growth at 35 °C. The pH range for growth was 5-9. Strains from different phylogenetic clusters varied in multiple phenotypic and chemotaxonomic characterizations. Thus, we propose three novel species Bifidobacterium apousia sp. nov. whose type strain is W8102T (=CGMCC 1.18893 T = JCM 34587 T), Bifidobacterium choladohabitans sp. nov., whose type strain is B14384H11T (=CGMCC 1.18892 T = JCM 34586 T), and Bifidobacterium polysaccharolyticum sp. nov. whose type strain is W8117T (=CGMCC 1.18894 T = JCM 34588 T).

Mining genome traits that determine the different gut colonization potential of Lactobacillus and Bifidobacterium species.

Although the beneficial effects of probiotics are likely to be associated with their ability to colonize the gut, little is known about the characteristics of good colonizers. In a systematic analysis of the comparative genomics, we tried to elucidate the genomic contents that account for the distinct host adaptability patterns of Lactobacillus and Bifidobacterium species. The Bifidobacterium species, with species-level phylogenetic structures affected by recombination among strains, broad mucin-foraging activity, and dietary-fibre-degrading ability, represented niche conservatism and tended to be host-adapted. The Lactobacillus species stretched across three lifestyles, namely free-living, nomadic and host-adapted, as characterized by the variations of bacterial occurrence time, guanine-cytosine (GC) content and genome size, evolution event frequency, and the presence of human-adapted bacterial genes. The numbers and activity of host-adapted factors, such as bile salt hydrolase and intestinal tissue-anchored elements, were distinctly distributed among the three lifestyles. The strains of the three lifestyles could be separated with such a collection of colonization-related genomic content (genes, genome size and GC content). Thus, our work provided valuable information for rational selection and gut engraftment prediction of probiotics. Here, we have found many interesting predictive results for bacterial gut fitness, which will be validated in vitro and in vivo.

Host-Diet Effect on the Metabolism of Bifidobacterium.

Bifidobacterium has a diverse host range and shows several beneficial properties to the hosts. Many species should have co-evolved with their hosts, but the phylogeny of Bifidobacterium is dissimilar to that of host animals. The discrepancy could be linked to the niche-specific evolution due to hosts' dietary carbohydrates. We investigated the relationship between bifidobacteria and their host diet using a comparative genomics approach. Since carbohydrates are the main class of nutrients for bifidobacterial growth, we examined the distribution of carbohydrate-active enzymes, in particular glycoside hydrolases (GHs) that metabolize unique oligosaccharides. When bifidobacterial species are classified by their distribution of GH genes, five groups arose according to their hosts' feeding behavior. The distribution of GH genes was only weakly associated with the phylogeny of the host animals or with genomic features such as genome size. Thus, the hosts' dietary pattern is the key determinant of the distribution and evolution of GH genes.

Structure and evolution of the bifidobacterial carbohydrate metabolism proteins and enzymes.

Bifidobacteria have attracted significant attention because they provide health-promoting effects in the human gut. In this review, we present a current overview of the three-dimensional structures of bifidobacterial proteins involved in carbohydrate uptake, degradation, and metabolism. As predominant early colonizers of the infant's gut, distinct bifidobacterial species are equipped with a panel of transporters and enzymes specific for human milk oligosaccharides (HMOs). Interestingly, Bifidobacterium bifidum and Bifidobacterium longum possess lacto-N-biosidases with unrelated structural folds to release the disaccharide lacto-N-biose from HMOs, suggesting the convergent evolution of this activity from different ancestral proteins. The crystal structures of enzymes that confer the degradation of glycans from the mucin glycoprotein layer provide a structural basis for the utilization of this sustainable nutrient in the gastrointestinal tract. The utilization of several plant dietary oligosaccharides has been studied in detail, and the prime importance of oligosaccharide-specific ATP-binding cassette (ABC) transporters in glycan utilisations by bifidobacteria has been revealed. The structural elements underpinning the high selectivity and roles of ABC transporter binding proteins in establishing competitive growth on preferred oligosaccharides are discussed. Distinct ABC transporters are conserved across several bifidobacterial species, e.g. those targeting arabinoxylooligosaccharide and α-1,6-galactosides/glucosides. Less prevalent transporters, e.g. targeting ß-mannooligosaccharides, may contribute to the metabolic specialisation within Bifidobacterium. Some bifidobacterial species have established symbiotic relationships with humans. Structural studies of carbohydrate-utilizing systems in Bifidobacterium have revealed the interesting history of molecular coevolution with the host, as highlighted by the early selection of bifidobacteria by mucin and breast milk glycans.

Metagenomic Analyses of Bifidobacterial Communities.

Bifidobacteria represent highly prevalent and abundant members of the gut microbiota during mammalian infancy. In this context, bifidobacterial species have been shown to be correlated with many aspects of host health by means of direct interactions with the host and cohabiting microbes. Metagenomic sequencing of fecal DNA represents a valuable approach for taxonomic and functional profiling of bacterial populations, and has allowed us to appreciate the relevance of bifidobacterial taxa in such complex bacterial communities, especially during the first stages of life.

Lactulose ingestion causes an increase in the abundance of gut-resident bifidobacteria in Japanese women: a randomised, double-blind, placebo-controlled crossover trial.

The genus Bifidobacterium comprises various bacterial species, and the complement of species within the human intestinal tract differs from individual to individual. The balance of these bifidobacterial species remains poorly understood, although it is known that the abundance of bifidobacteria increases following the ingestion of prebiotics. We previously conducted a randomised, placebo-controlled, double-blind, crossover study of 2 g/day lactulose ingestion for 2 weeks in 60 Japanese women. To study the effect of lactulose ingestion on each bifidobacterial species, here, we measured the abundance of each of the principal bifidobacterial species. After lactulose ingestion, the log cell counts of the Bifidobacterium adolescentis group (8.97±0.08 vs 9.39±0.08, P=0.0019), Bifidobacterium catenulatum group (9.45±0.10 vs 9.65±0.10, P=0.0032) and Bifidobacterium longum group (9.01±0.07 vs 9.29±0.07, P=0.0012) were significantly higher than in the placebo ingestion control group. However, the log cell counts were similar for Bifidobacterium breve (8.12±0.12 vs 8.33±0.12, P=0.20), Bifidobacterium bifidum (9.08±0.12 vs 9.42±0.14, P=0.095) and Bifidobacterium animalis subspecies lactis (8.65±0.53 vs 8.46±0.46, P=0.77). Cluster analysis of the log cell count data at the bifidobacterial species level revealed three distinct clusters, but the combinations and ratios of the constituent bifidobacteria were not affected by lactulose ingestion. Furthermore, principal coordinate analysis of the intestinal microbiota in the lactulose and placebo ingestion groups using Illumina MiSeq showed no significant differences in the intestinal microbiota as a whole. These results suggest that 2 g/day lactulose ingestion for 2 weeks significantly increases the abundance of intestinal bifidobacteria, but does not affect the intestinal microbiota as a whole.

Gut microbiome stability and dynamics in healthy donors and patients with non-gastrointestinal cancers.

As microbial therapeutics are increasingly being tested in diverse patient populations, it is essential to understand the host and environmental factors influencing the microbiome. Through analysis of 1,359 gut microbiome samples from 946 healthy donors of the Milieu Intérieur cohort, we detail how microbiome composition is associated with host factors, lifestyle parameters, and disease states. Using a genome-based taxonomy, we found biological sex was the strongest driver of community composition. Additionally, bacterial populations shift across decades of life (age 20-69), with Bacteroidota species consistently increased with age while Actinobacteriota species, including Bifidobacterium, decreased. Longitudinal sampling revealed that short-term stability exceeds interindividual differences. By accounting for these factors, we defined global shifts in the microbiomes of patients with non-gastrointestinal tumors compared with healthy donors. Together, these results demonstrated that the microbiome displays predictable variations as a function of sex, age, and disease state. These variations must be considered when designing microbiome-targeted therapies or interpreting differences thought to be linked to pathophysiology or therapeutic response.

Five novel bifidobacterial species isolated from faeces of primates in two Czech zoos: Bifidobacterium erythrocebi sp. nov., Bifidobacterium moraviense sp. nov., Bifidobacterium oedipodis sp. nov., Bifidobacterium olomucense sp. nov. and Bifidobacterium panos sp. nov.

Five Bifidobacterium strains, VB23T, VB24T, VB25T, VB26T and VB31T, were isolated from chimpanzee (Pan troglodytes), cotton-top tamarin (Saguinus oedipus), Goeldi's marmoset (Callimico goeldii), moustached tamarin (Saguinus mystax) and patas monkey (Erythrocebus patas), respectively, which were kept in two Czech zoos. These strains were isolated from faecal samples and were Gram-positive, non-motile, non-sporulating, anaerobic and fructose-6-phosphate phosphoketolase-positive. Phylogenetic analyses based on 16S rRNA revealed close relatedness between VB23T and Bifidobacterium angulatum LMG 11039T (96.0 %), VB24T and Bifidobacterium pullorum subsp. pullorum DSM 20433T (96.1 %), VB25T and Bifidobacterium goeldii LMG 30939T (96.5 %), VB26T and Bifidobacterium imperatoris LMG 30297T (98.1 %), and VB31T and B. angulatum LMG 11039T (99.40 %). Internal transcribed spacer profiling revealed that VB23T, VB24T, VB25T, VB26T and VB31T had highest similarity to Bifidobacterium breve LMG 13208T (77.2 %), Bifidobacterium longum subsp. infantis ATCC 15697T (85.8 %), Bifidobacterium biavatii DSM 23969T (76.9 %), B. breve LMG 13208T (81.2 %) and B. angulatum LMG 11039T (88.2 %), respectively. Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) analyses with their closest neighbours supported the independent phylogenetic positions of the strains with values between 86.3 and 94.3 % for ANI and 25.8 and 54.9 % for dDDH. These genomic and phylogenetic analyses suggested that the evaluated strains were novel Bifidobacterium species named Bifidobacterium erythrocebi sp. nov. (VB31T=DSM 109960T=CCUG 73843T), Bifidobacterium moraviense sp. nov. (VB25T=DSM 109958T=CCUG 73842T), Bifidobacterium oedipodis sp. nov. (VB24T=DSM 109957T=CCUG 73932T), Bifidobacterium olomucense sp. nov. (VB26T=DSM 109959T=CCUG 73845T) and Bifidobacterium panos sp. nov. (VB23T=DSM 109963T=CCUG 73840T).

Efeito da colostroterapia e do leite materno no estabelecimento da microbiota de recém-nascidos prematuros / Effect of breast milk and oropharyngeal administration of colostrum on the establishment of the microbiota of preterm newborns

A colonização inicial da microbiota humana é de suma importância, desempenhando um papel fundamental no desenvolvimento imunológico, nutricional, metabólico e neurológico. Recémnascidos prematuros e de baixo peso muitas vezes precisam permanecer internados em unidades de terapia intensiva e frequentemente a dieta enteral trófica é limitada, devido à imaturidade do sistema digestivo ou estado clínico do recém-nascido. Nesse contexto, a amamentação é importante para o desenvolvimento do recém-nascido e para a colonização inicial do trato gastrointestinal. Além disso, a administração de colostro como imunoterapia oral já foi descrita como uma terapia segura, viável e bem tolerável por recém-nascidos. Sendo assim, este projeto avaliou o efeito da administração de leite materno, seja através da dieta ou colostroterapia, no desenvolvimento da microbiota oral e intestinal de recém-nascidos prematuros. Foi realizado um estudo longitudinal e observacional, onde foram recrutados 20 neonatos prematuros para a análise da microbiota oral e 56 para a análise da microbiota intestinal. Foram coletadas amostras de saliva e fezes dos neonatos, e leite materno das mães destes neonatos, e realizado sequenciamento do gene 16S rRNA destas amostras, além da dosagem de imunoglobulina A (IgA) nas fezes dos recém-nascidos. Para análise estatística, foi utilizado o software SPSS e R Studio, adotando significância de 5% para os testes. O leite materno de mães de recém-nascidos prematuros apresenta composição que muda ao longo do tempo, com aumento de Staphylococcus e Streptococcus e diminuição de Corynebacterium 1. A colostroterapia possui efeito benéfico sobre a microbiota oral, com aumento de gêneros como Staphylococcus, Bifidobacterium e Bacteroides. Adicionalmente, existe diferença na microbiota intestinal quando diferentes proporções de leite materno são oferecidas durante a primeira semana de vida, além de maiores níveis de IgA total nas amostras de fezes de neonatos que receberam maiores proporções de leite materno

The initial colonization of the human microbiota is of paramount importance, playing a fundamental role in immunological, nutritional, metabolic, and neurological development. Premature and low-birth-weight newborns often need to remain hospitalized in intensive care units and often enteral trophic diet is limited due to the immaturity of the digestive system or the newborn's clinical status. In this context, breastfeeding is important for the newborn's development and for the initial colonization of the gastrointestinal tract. Furthermore, the administration of colostrum as oral immunotherapy has been described as a safe, viable and well-tolerable therapy for newborns. Therefore, this project evaluated the effect of administering breast milk, either through diet or administration of colostrum, on the development of the oral and intestinal microbiota of preterm newborns. A longitudinal and observational study was carried out, where 20 premature neonates were recruited for the analysis of the oral microbiota and 56 for the analysis of the intestinal microbiota. Samples of saliva and feces were collected from the newborns, and breast milk from the mothers of these newborns, and 16S rRNA gene sequencing was performed from these samples, in addition to the dosage of immunoglobulin A (IgA) in the feces of the newborns. For statistical analysis, SPSS and R Studio software were used, adopting a significance of 5% for the tests. Breast milk from mothers of premature newborns has a composition that changes over time, with an increase in Staphylococcus and Streptococcus and a decrease in Corynebacterium 1. Administration of colostrum has a beneficial effect on the oral microbiota, with an increase in genera such as Staphylococcus, Bifidobacterium and Bacteroides. Additionally, there is a difference in the intestinal microbiota when different proportions of breast milk are offered during the first week of life, in addition to higher levels of total IgA in stool samples from newborns who received higher proportions of breast mil

Impact of diet and synbiotics on selected gut bacteria and intestinal permeability in individuals with excess body weight - A Prospective, Randomized Study.

Overweight and obese individuals may have leaky intestinal barrier and microbiome dysbiosis. The aim of this study was to determine whether body mass reduction with diet and synbiotics in an adult person with excess body mass has an influence on the gut microbiota and zonulin concentration. The study was a single blinded trial. 60 persons with excess body mass were examined. Based on randomization, patients were qualified either to the intervention group (Synbiotic group) or to the control group (Placebo group). Anthropometric measurements, microbiological assessment of faecal samples and zonulin concentration in the stool were performed before and after observation. After 3-months, an increase in the variety of intestinal bacteria (increase in the Shannon-Weaver index and the Simpson index) and a decrease in concentration of zonulin in faecal samples were observed in the Synbiotic group. Also, statistically significant correlation between zonulin and Bifidobacterium spp. (Spearman test, R=-0.51; p=0.0040) was noticed. There were no significant relationships between the body mass, BMI and changes in the intestinal microbiota or zonulin concentrations. The use of diet and synbiotics improved the condition of the microbiota and intestinal barrier in patients in the Synbiotic group.

Neonatal gut colonization by Bifidobacterium is associated with higher childhood cytokine responses.

The gut microbiota is a major stimulus for the immune system, and late acquisition of bacteria and/or reduced complexity of the gut flora may delay adaptive immune maturation. However, it is unknown how the gut bacterial colonization pattern in human infants is related to T cell activation during early childhood. We followed 65 Swedish children in the FARMFLORA cohort, from birth up to 3 years of age. In fecal samples collected at several time points during the first year of life, the gut colonization pattern was investigated with the use of both 16S rRNA next generation sequencing (NGS) and culture-based techniques. This was related to production of IL-13, IL-5, IL-6, TNF, IL-1ß and IFN-γ by PHA-stimulated fresh mononuclear cells and to proportions of CD4+ T cells that expressed CD45RO at 36 months of age. Both NGS and culture-based techniques showed that colonization by Bifidobacterium at 1 week of age associated with higher production of IL-5, IL-6, IL-13, TNF and IL-1ß at 36 months of age. By contrast, gut colonization by Enterococcus, Staphylococcus aureus or Clostridium in early infancy related inversely to induced IL-13, IL-5 and TNF at 3 years of age. Infants with elder siblings produced more cytokines and had a larger fraction of CD45RO+ T cells compared to single children. However, controlling for these factors did not abolish the effect of colonization by Bifidobacterium on immune maturation. Thus, gut colonization in early infancy affects T cell maturation and Bifidobacterium may be especially prone to induce infantile immune maturation.

Microbiological, Physicochemical, and Immunological Analysis of a Commercial Cashew Nut-Based Yogurt.

Nut-based milks and yogurts are gaining popularity, but may not offer the same benefits as dairy yogurts to consumers. Cashew nuts often cause severe allergic reactions, and cashew nut allergens are stable to several types of processing. To compare its characteristics to dairy yogurt and characterize the effects of fermentation on the Ana o 1-3 cashew nut allergens, a commercial yogurt made from cashew nuts (Cashewgurt) was evaluated for microbiological, physiochemical, and immunological properties. Average counts for lactobacilli and Streptococcus thermophilus were greater than 10 million colony forming units per milliliter, indicating the capacity to provide a health benefit. Cashewgurt pH and viscosity values were comparable to cow milk yogurts, and it was off white in color. SDS-PAGE analysis indicated a clear reduction in Ana o 1 and 2, and immuno-assay with polyclonal anti-cashew IgG antibody and cashew-allergic IgE indicated an overall reduction in allergen content. In contrast, SDS-PAGE, mass spectrometry, immunoblot, and ELISA all revealed that Ana o 3 was relatively unaffected by the fermentation process. In conclusion, Ana o 1 and Ana o 2 are sensitive to degradation, while Ana o 3 survives lactic acid bacterial fermentation during yogurt production. The analysis presented here indicates that cashew nut yogurt is not suitable for those with cashew nut allergy.

Bifidobacteria in two-toed sloths (Choloepus didactylus): phylogenetic characterization of the novel taxon Bifidobacterium choloepi sp. nov.

Seven bifidobacterial strains were isolated from the faeces of two adult males of the two-toed sloth (Choloepus didactylus) housed in Parco Natura Viva, in Italy. Comparative sequence analysis of 16S rRNA and of five housekeeping (hsp60, rpoB, clpC, dnaJ, dnaG) genes revealed that these strains were classified into two clusters. On the basis of 16S rRNA gene sequence similarity, the type strain of Bifidobacterium catenulatum subsp. kashiwanohense DSM 21854T (95.4 %) was the closest neighbour to strain in Cluster I (BRDM 6T), whereas the type strain of Bifidobacterium dentium DSM 20436T (values were in the range of 98‒99.8 %) was the closest neighbour to the other six strains in Cluster II. The average nucleotide identity (ANI) values of BRDM 6T and of strains in Cluster II with the closely related type strains were 76.0 and 98.9 % (mean value) respectively. Therefore, genotyping based on the genome sequence of the strain BRDM 6T combined with phenotypic analyses clearly revealed that the strain BRDM 6T represents a novel species for which the names Bifidobacterium choloepi sp. nov. (BRDM 6T=NBRC 114053T=BCRC 81222T) is proposed.

Risk factors for type 1 diabetes, including environmental, behavioural and gut microbial factors: a case-control study.

Type 1 diabetes (T1D) is a common autoimmune disease that is characterized by insufficient insulin production. The onset of T1D is the result of gene-environment interactions. Sociodemographic and behavioural factors may contribute to T1D, and the gut microbiota is proposed to be a driving factor of T1D. An integrated preventive strategy for T1D is not available at present. This case-control study attempted to estimate the exposure linked to T1D to identify significant risk factors for healthy children. Forty children with T1D and 56 healthy controls were included in this study. Anthropometric, socio-economic, nutritional, behavioural, and clinical data were collected. Faecal bacteria were investigated by molecular methods. The findings showed, in multivariable model, that the risk factors for T1D include higher Firmicutes levels (OR 7.30; IC 2.26-23.54) and higher carbohydrate intake (OR 1.03; IC 1.01-1.05), whereas having a greater amount of Bifidobacterium in the gut (OR 0.13; IC 0.05 - 0.34) was a protective factor for T1D. These findings may facilitate the development of preventive strategies for T1D, such as performing genetic screening, characterizing the gut microbiota, and managing nutritional and social factors.

Proposal of Bifidobacterium saeculare Biavati et al. 1992 as a later heterotypic synonym of Bifidobacterium gallinarum Watabe et al. 1983 and Bifidobacterium gallinarum subsp. saeculare subsp. nov.

In 2018, Nouioui et al. transferred Bifidobacterium gallinarum and Bifidobacterium saeculare to Bifidobacterium pullorum as B. pullorum subsp. gallinarum and B. pullorum subsp. saeculare on the basis of digital DNA-DNA hybridization (dDDH) values. These two new subspecies were validated in the same year. However, we found that the genome (GenBank/ENA/DDBJ accession number JGZJ01000000) of B. pullorum used by Nouioui et al. in the dDDH analysis cannot represent B. pullorum. So, the taxonomic relationship between B. gallinarum, B. saeculare and B. pullorum should be re-examined. B. pullorum DSM 20433T had 88.7-89.0 % average nucleotide identity (ANI) values and 37.5-38.0 % dDDH values to the type strains of B. gallinarum and B. saeculare, respectively, less than the threshold for species demarcation, confirming that B. pullorum represents a different species from B. gallinarum and B. saeculare. The ANI values and dDDH values between the type strains of B. gallinarum and B. saeculare were 96.7-96.9 % and 73.0-73.3 %, respectively, greater than the threshold for species demarcation, confirming that they represent the same species. Relatively low dDDH values (less than the 79-80 % threshold for subspecies demarcation) between the type strains of B. gallinarum and B. saeculare indicated that B. saeculare can be considered as a subspecies of B. gallinarum. On the basis of the results presented here, (i) B. gallinarum and B. saeculare should not be transferred to B. pullorum; (ii) we propose B. saeculare Biavati et al. 1992 as a later heterotypic synonym of B. gallinarum Watabe et al. 1983 and as a new subspecies of B. gallinarum, for which the name B. gallinarum subsp. saeculare subsp. nov. is proposed.

Commensal Relationship of Three Bifidobacterial Species Leads to Increase of Bifidobacterium in Vitro Fermentation of Sialylated Immunoglobulin G by Human Gut Microbiota.

Sialylated immunoglobulin G (IgG) is an important immunoglobulin in breast milk, but its effect on adult gut microbiota is not yet clear due to digestion by pepsin. Based on our previous IgG protecting study, effects of sialylated IgG on gut microbiota were investigated by in vitro anaerobic fermentation in the present study. It was found that the addition of sialylated IgG could significantly promote the growth of Bifidobacterium. Meanwhile, three bifidobacterial species B. bifidum CCX 19061, Bembidion breve CCX 19041, and B. longum subsp. infantis CCX 19042 were isolated. Furthermore, B. breve CCX 19041 and B. longum subsp. infantis CCX 19042 showed co-culture growth property with B. bifidum CCX 19061 in a sialylated IgG-based medium, which was also supported by changes of free monosaccharides and N-glycan structure. These findings suggest that the increase of Bifidobacterium in vitro fermentation is attributed to the commensal relationship of the three bifidobacterial species by utilizing sugars released from sialylated IgG.

A comparison of the inhibitory activities of Lactobacillus and Bifidobacterium against Penicillium expansum and an analysis of potential antifungal metabolites.

The infection of fruits by Penicillium expansum (P. expansum) do not only cause economic loss but also potentially endanger human health, especially because few biocontrol agents against this fungus have been well studied yet. In this work, to verity the antifungal activity against P. expansum of 22 Bifidobacterium and 44 Lactobacillus, dual-culture overlay assay, microtiter plate well assay and agar spot assay were successively performed. One of the strain, Bifidobacterium adolescentis (B. adolescentis) CCFM1108 exhibited the most potent inhibition ability among all tested strains. Additionally, we showed that multiple antifungal compounds produced by tested strain synergistically inhibit the growth of P. expansum, including lactic acid, acetic acid, 3-phenyllactic acid and p-hydroxyphenyllactic acid. Those active compounds mentioned were detected in the cell-free supernatant and characterized by metabolomics analysis using GC-MS. Correspondingly, B. adolescentis CCFM1108 supernatant disrupted plasma membrane integrity of the P. expansum mycelial and drastically reduced patulin production in P. expansum. The inhibitive effects of B. adolescentis CCFM1108 were also confirmed with three other P. expansum strains. The active inhibitory properties of Bifidobacterium strains, especially B. adolescentis CCFM1108, indicate that B. adolescentis can be potentially used as a novel bioagent to prevent or delay fungal spoilage on fruit.