Xin Wang

The gut microbiota serves as a critical interface for host immunity, making it a promising target for probiotic intervention. In this study, we investigated the immunomodulatory potential of the strain Bifidobacterium breve (B. breve) MN15965 and the underlying role of gut bacterial communities in this process. We first assessed its in vitro immunomodulatory activity by measuring nitric oxide and cytokine secretion in THP-1 macrophages. Subsequently, an immunosuppressed mouse model was established by treating BALB/c mice with cyclophosphamide (CTX), a chemotherapeutic agent known to cause immune dysfunction and mucosal damage. In this model, we performed a series of analyses, including H&E staining, measurement of hematological parameters and serum cytokines/immunoglobulins, quantification of fecal short-chain fatty acids (SCFAs) by gas chromatography, and profiling of gut microbiota composition via 16S rRNA gene amplicon sequencing. The results showed that MN15965 supernatant enhanced TNF-α, IL-1β, and GM-CSF secretion in THP-1 cells, promoting M1 macrophage activation in vitro. In the in vivo model, MN15965 administration restored spleen and thymus tissue integrity and improved physiological indices, hematological parameters, and immunoglobulin levels. Furthermore, MN15965 increased fecal SCFAs, particularly butyric and valeric acid, increased gut bacterial diversity, and enriched potentially beneficial SCFA-producing taxa, including Lachnospiraceae and Eubacterium. These findings demonstrate that B. breve MN15965 alleviated CTX-induced immunosuppression by activating immune responses, regulating gut bacterial communities, and boosting SCFA production.

Background/Objectives: Early-life skeletal growth is critical for achieving optimal peak bone mass. This study aimed to investigate whether synbiotic supplementation with 2′-fucosyllactose (2′-FL) and Lactiplantibacillus plantarum Hi188 (Hi188) influences bone development in growing mice and its potential association with gut microbial modulation. Methods: Three-week-old BALB/c mice were orally supplemented with 2′-FL, Hi188, or their combinations at low and medium doses for 7 weeks. Bone length, microarchitecture and mechanical properties were analyzed. Serum bone turnover markers and osteogenic gene expression were analyzed by ELISA and qRT-PCR, respectively. Gut microbiota composition, and short-chain fatty acid (SCFA) production were analyzed by 16S-rRNA sequencing and GC-FID, respectively. Correlation associations among microbial taxa, SCFAs, and skeletal parameters were also assessed. Results: Medium-dose synbiotic supplementation significantly increased tibial and spine length without altering body weight or intestinal histology. Trabecular bone density and volume fraction were elevated, accompanied by reduced trabecular separation and improved mechanical strength. Serum BALP levels were increased and TRACP-5b levels were reduced, together with upregulation of osteogenesis- and matrix-related genes. Synbiotic treatment also modulated gut microbial composition, enriched SCFA-associated taxa, and significantly enhanced total and individual SCFA levels. Correlation analyses revealed selective associations among specific microbial taxa, SCFAs, and skeletal structural and molecular parameters. Conclusions: Medium doses of synbiotic supplementation were associated with improved skeletal growth and bone quality during development, alongside coordinated modulation of bone remodeling and gut microbial metabolic activity. These findings suggest its potential as a functional nutritional strategy for supporting early bone health.

This study was carried out to compare gut microbial community composition, diversity, and function with and without microbiota transplantation in a newly-hatched chick model. Two hundred and forty newly-hatched Arbor Acre male broilers were assigned randomly to either a microbiota transplantation group or a control group (n = 120; 6 replicates per group, and 20 broilers per replicate). Both groups were fed a basal diet that met all nutritional requirements, composed of corn, soybean meal, cottonseed meal, vitamins, and minerals. The microbiota transplantation group was inoculated with the microbiota from the ceca of healthy adult chicks on day 1 and 2, respectively, over a trial period of 42 d. For both groups, the numbers of total bacteria, Lactobacillus and Escherichia coli, operational taxonomic unit partitioning and classification, taxonomic composition, comparative microbiota, and key bacterial species were identified by a 16S rRNA sequencing analysis. The results showed that Aestuariispira, Christensenella, Fervidicella, Gracilibacter, Haloferula, Mycoplasma, Novispirillum, and Pantoea were more abundant (p < 0.05) in the microbiota transplantation group than those in the control group. This indicates that microbiota transplantation could directly influence the abundances of specific bacterial taxa in the ileum and cecum of broilers. These findings provide insight into the modulation of gut health for patients with abnormal bowel function, which should be of great interest to researchers in the area of gastroenterology, applied microbiology, and animal sciences.

The Prevotella enterotype type is a human traditional enterotype with high dietary fiber intake, which is related to healthy ageing and Parkinson’s disease development. Manipulations of the dwelled gut microbes by dietary isomalto-oligosaccharides efficiently sustained Prevotella type enterotypes, indicating that it can be used in the improvement of elderly health by increasing the gut transit time.

In this study, we evaluated the effects of different feeding methods on the characteristics of intestinal flora and gas production in infants and toddlers by using an in vitro simulated intestinal microecology fermentation and organoid model. We found that the feeding method influences intestinal gas and fecal ammonia production in infants and toddlers. Supplementation with milk powder for infants in the late lactation period could promote the proliferation of beneficial bacteria, including Bifidobacteria. Intestinal flora gas production in a culture medium supplemented with fucosyllactose (2′-FL) was significantly lower than that in media containing other carbon sources. In conclusion, 2′-FL may reduce gas production in infant and toddler guts through two mechanisms: first, it cannot be used by harmful intestinal bacteria to produce gas; second, it can inhibit intestinal mucosa colonization by harmful bacteria by regulating the expression of intestinal epithelial pathogenic genes/signaling pathways, thus reducing the proliferation of gas-producing harmful bacteria in the gut.

Gut microbiota dysbiosis is closely associated with ulcerative colitis (UC). Prebiotic therapy is a potential approach for UC management especially remission maintaining. Xylo-oligosaccharide (XOS) is an efficient prebiotic with proven health benefits and few side effects. However, the effects of XOS on the gut microbiota of patients with UC have not been investigated previously. The aim of this study was to evaluate the prebiotic effects of XOS on the fecal microbiota of patients with UC in clinical remission using an in vitro fermentation model. Five patients with UC in clinical remission and five healthy volunteers were enrolled in this study. Fresh fecal samples of UC patients were diluted and inoculated in yeast extract, casitone and fatty acid (YCFA) medium alone or with XOS. After fermentation for 48 h, samples were collected for 16S rDNA sequencing to investigate the gut microbiota composition. Differences in the gut microbiota between healthy volunteers and UC patients in clinical remission were detected using original fecal samples. Subsequently, the differences between the YCFA medium alone or with XOS samples were analyzed to illustrate the effects of XOS on the gut microbiota of UC patients. In both principal coordinate analysis (PCoA) and principal component analysis (PCA), the fecal samples of UC patients differed from those of healthy volunteers. Linear discriminant analysis effect size (LEfSe) analysis revealed that the relative abundances of g_Roseburia and g_Lachnospiraceae_ND3007_group were higher in healthy volunteers than in UC patients, while o_Lactobacillales abundance showed the opposite trend (P < 0.05). Wilcoxon rank-sum test bar plot showed that the abundances of g_Eubacterium_halli_group and g_Lachnospiraceae_ND3007_group were higher in the healthy volunteers than in the UC patients (P < 0.05). In addition, in UC patients, the Wilcoxon rank-sum test showed that XOS fermentation promoted the growth of bacterial groups including g_Roseburia, g_Bifidobacterium, and g_Lactobacillus, which is beneficial for recovery of intestinal diseases. These results suggest that XOS can relieve dysbiosis in the feces of UC patients in clinical remission and thus represent a potential prebiotic material for maintaining remission.

Segmented filamentous bacteria (SFB) are well known for their functions in the immunoregulation of hosts including the promotion of Th17 cell differentiation, B cell maturation, and immune system development. However, most analyses of SFB have focused on animal models, and thus, investigation of SFB prevalence in humans and their roles in human immunoregulation and health is needed. Although little is known overall of SFB prevalence in humans, they are characteristically abundant in animals during weaning. In this study, SFB-like bacteria were detected in ileal lavage samples from human children that were aged between 1 to 17 years old by scanning electron microscopy (SEM) analysis, and their insertion into the mucosa was also observed. In addition, the expression of SFB flagellin at the human bacterial interface was observed by immunohistochemistry (IHC) and western blot. Moreover, two pairs of primers specific for SFB, but targeting different genes, were used to detect SFB in human intestinal lavage samples. These analyses indicated that SFB were present in over 50% of patient ileal samples independent of age. High-throughput gene sequencing indicated that different SFB strains were detected among samples. Between nine and 23 SFB flagellin gene operational taxonomic units were identified. In addition to evaluating the prevalence of SFB in human samples, correlations between SFB presence and chief complaints of clinical symptoms were evaluated, as well as the relationship between SFB and patient serum immunoglobulin concentrations. SFB prevalence was significantly higher in hematochezia patients (68%) than in abdominal pain (56.10%) and diarrhea (43.75%) patients. Furthermore, the concentrations of serum IgA, IgM, and IgE, were similar between SFB-positive and SFB-negative patient groups, although IgG concentrations were significantly higher in the SFB-negative group.

A sustainable food supply is an ever-growing public and planetary health concern influenced by food culture, food practices, and dietary patterns. Globally, the consumption of plant foods that offer physiological and biochemical benefits is increasing. In recent years, products made from yacon (Smallanthus sonchifolius) tubers and leaves, e.g., in the form of syrup, powder, and herbal tea, have steadily emerged with scientific evidence to validate their possible health claims. Yacon was introduced to New Zealand in 1966, and its products can now be produced on a commercial scale. This paper reviews literature published mainly in the last 10 years concerning the health-related properties of yacon as a wholesome foodstuff and its bioactive components, e.g., fructooligosaccharides. Literature was sourced from Web of Science, PubMed, EBSCO Health, and Google Scholar up to June 2019. The potential markets for yacon in the field of food technology and new dietotherapy applications are discussed. Furthermore, the unique features of New Zealand-produced yacon syrup are introduced as a case study. The paper explores the scientific foundation in response to the growing public interest in why and how to use yacon.

Segmented filamentous bacteria (SFB) are commensal organisms that grow by anchoring a specialized holdfast structure to the intestinal walls of a variety of animals. Interaction of SFB with Peyer’s patches in mice promotes the post-natal maturation of the immune system. We previously reported that the colonization of SFB in humans mainly occurs by 36 months of age, and is difficult to be detected afterward. In this study, we measured the level of SFB in intestinal fluids of human children. SFB were found via qPCR to represent a small fraction of the whole SFB-positive microbiota (10⁵ SFB in 10¹¹ total bacteria). Bacteria with filamentous segmented morphology were observed in intestinal fluids via fluorescent in situ hybridization, and from gut biopsies via scanning electron microscopy. SFB-specific DNA and peptide fragments were also identified via multiple displacement amplification PCR and mass spectrometry. There was an overall positive correlation between the presence of SFB and the titer of total secretory immunoglobulin A (sIgA), which is more apparent in intestinal fluids of the age group of 8–36 months. Afterward there was a decline of SFB in numbers correlated with a reduction of total sIgA. RT-qPCR analysis of the terminal ileal biopsies revealed that the expression of Th17 pathway genes were induced in SFB-positive samples, while the markers of T and B cell receptor signaling pathways were also upregulated. Collectively, these data suggest that SFB is a rare member of microbiota, and may play an important role in the development of human gut immunity.