Akkermansia muciniphilahas evolved to specialize in the degradation and utilization of host mucus, which it may use as the sole source of carbon and nitrogen. Mucus degradation and fermentation byA. muciniphilaare known to result in the liberation of oligosaccharides and subsequent production of acetate, which becomes directly available to microorganisms in the vicinity of the intestinal mucosa. Coculturing experiments ofA.muciniphilawith non-mucus-degrading butyrate-producing bacteriaAnaerostipes caccae,Eubacterium hallii, andFaecalibacterium prausnitziiresulted in syntrophic growth and production of butyrate. In addition, we demonstrate that the production of pseudovitamin B₁₂byE. halliiresults in production of propionate byA. muciniphila, which suggests that this syntrophy is indeed bidirectional. These data are proof of concept for syntrophic and other symbiotic microbe-microbe interactions at the intestinal mucosal interface. The observed metabolic interactions betweenA.muciniphilaand butyrogenic bacterial taxa support the existence of colonic vitamin and butyrate production pathways that are dependent on host glycan production and independent of dietary carbohydrates. We infer that the intestinal symbiontA. muciniphilacan indirectly stimulate intestinal butyrate levels in the vicinity of the intestinal epithelial cells with potential health benefits to the host.IMPORTANCEThe intestinal microbiota is said to be a stable ecosystem where many networks between microorganisms are formed. Here we present a proof of principle study of microbial interaction at the intestinal mucus layer. We show that indigestible oligosaccharide chains within mucus become available for a broad range of intestinal microbes after degradation and liberation of sugars by the speciesAkkermansia muciniphila. This leads to the microbial synthesis of vitamin B₁₂, 1,2-propanediol, propionate, and butyrate, which are beneficial to the microbial ecosystem and host epithelial cells.

Host glycans are paramount in regulating the symbiotic relationship between humans and their gut bacteria. The constant flux of host-secreted mucin at the mucosal layer creates a steady niche for bacterial colonization. Mucin degradation by keystone species subsequently shapes the microbial community. This study investigated the transcriptional response during mucin-driven trophic interaction between the specialised mucin-degrader Akkermansia muciniphila and a butyrogenic gut commensal Anaerostipes caccae. A. muciniphila monocultures and co-cultures with non-mucolytic A. caccae from the Lachnospiraceae family were grown anaerobically in minimal media supplemented with mucin. We analysed for growth, metabolites (HPLC analysis), microbial composition (quantitative reverse transcription PCR), and transcriptional response (RNA-seq). Mucin degradation by A. muciniphila supported the growth of A. caccae and concomitant butyrate production predominantly via the acetyl-CoA pathway. Differential expression analysis (DESeq 2) showed the presence of A. caccae induced changes in the A. muciniphila transcriptional response with increased expression of mucin degradation genes and reduced expression of ribosomal genes. Two putative operons that encode for uncharacterised proteins and an efflux system, and several two-component systems were also differentially regulated. This indicated A. muciniphila changed its transcriptional regulation in response to A. caccae. This study provides insight to understand the mucin-driven microbial ecology using metatranscriptomics. Our findings show that the expression of mucolytic enzymes by A. muciniphila increases upon the presence of a community member. This could indicate its role as a keystone species that supports the microbial community in the mucosal environment by increasing the availability of mucin sugars.

The establishment of the gut microbiota immediately after birth is a dynamic process that may impact lifelong health. At this important developmental stage in early life, human milk oligosaccharides (HMOs) serve as specific substrates to shape the gut microbiota of the nursling. The well-orchestrated transition is important as an aberrant microbial composition and bacterial-derived metabolites are associated with colicky symptoms and atopic diseases in infants. Here, we study the trophic interactions between an HMO-degrader, Bifidobacterium infantis and the butyrogenic Anaerostipes caccae using carbohydrate substrates that are relevant in the early life period including lactose and total human milk carbohydrates. Mono- and co-cultures of these bacterial species were grown at pH 6.5 in anaerobic bioreactors supplemented with lactose or total human milk carbohydrates. A. caccae was not able to grow on these substrates except when grown in co-culture with B. infantis, leading to growth and concomitant butyrate production. Two levels of cross-feeding were observed, in which A. caccae utilised the liberated monosaccharides as well as lactate and acetate produced by B. infantis. This microbial cross-feeding points towards the key ecological role of bifidobacteria in providing substrates for other important species that will colonise the infant gut. The progressive shift of the gut microbiota composition that contributes to the gradual production of butyrate could be important for host-microbial crosstalk and gut maturation.

Background: Functional gastrointestinal disorders (FGIDs) are common early in life. The prevalence of FGIDs varies among countries but is unknown in Vietnam. The aim of this study is to assess the prevalence of FGIDs in healthy Vietnamese infants and young children. Methods: This was a cross-sectional, observational study involving healthy infants and young children between 0 – 48 months old in Hanoi, Vietnam. A representative total of 1511 subjects completed the validated questionnaire on paediatric FGIDs. Rome IV criteria were used to define FGIDs. Results: For Vietnamese infants (0–6 months) and young children (7–48 months), the prevalence of having at least one FGID was 10.0% and only 0.6% was having more than one FGID. Infantile regurgitation (9.3%) was the most prevalent FGID among infants 0—6 months of age while all other FGIDs had a low prevalence between 0—2.5%. For young children between 7 – 48 months old, functional constipation was the most common disorder at the rate of 5.6%. Association analysis revealed that the risk of infant regurgitation was significantly lower among infants with exclusively breastfeeding at 2 – 3 months and 3 – 4 months, formula initiation at 0 – 1 months, and higher paternal education level. The prevalence of functional constipation was significantly higher in male subjects, children in families with annual household income between 273,000,000 – 546,999,999 VND (or estimate around 11,800 – 23,800 USD), families with one child only, and formula feeding initiation at 1 – 2 months. Conclusions: The prevalence of FGIDs in Vietnamese infants and young children is relatively low compared to the published literature using Rome IV diagnostic criteria. Infantile regurgitation was the most common FGID in Vietnamese infants while functional constipation was most prevalent among Vietnamese young children. Trial registration: Netherlands Trial Registry Identifier: NL7286/NTR7495.

The study aimed to investigate the effect of fructo-oligosaccharides (FOS) on the growth and fermentation kinetics of Lactobacillus casei LC-01 (LC) and Lactobacillus acidophilus LA5 (LA) in cultured milk. Two commercially available FOS with different degree of polymerization (DP), namely Fibrulose F97 (DP, 2-20) and Fibruline Instant (DP, 3-60) were used at 4% (w/v) and 8% (w/v) respectively during fermentation and storage of cultured milk. Physicochemical properties and acidification kinetic of milk were measured throughout the fermentation. The concentration and DP values of the FOS do not seem to affect the growth of both probiotics during fermentation. Nevertheless, the pH and total soluble solid of milk fermented by both probiotics supplemented with FOS decreased tremendously during fermentation. It is noted that the percentage of lactic acid produced in L. acidophilus is higher than L. casei owing to the metabolic characteristic of the strain. The kinetic of maximum acidification rate Vmax of cultured milk was significantly higher with the addition of FOSs at 4%. However, FOS with lower DP seemed to enhance (p

Summary: The Human Microbiome, as well as the exploration of the microorganisms inhabiting the human body, are not only integral to the field of microbiology but represent an intrinsic part of all human beings. Consequently, along with scientists, artists have been inspired by the microbiome: transforming it in to tangible artefacts in order to critically question, reflect on and break down the barrier between humans and their microcohabitants. By artistic means, artists help us to understand how microbial research topics are inevitably affected by societal influences, including (health) politics, economics and the arts. Fifty Percent Human is a multidisciplinary artistic research project that aims to reshape our understanding of the human body and its environment as well as to explore possibilities for conscious coexistence in order to bridge the gap between science and society.