Biology subjects

Schaan, A. P.

Publications and source records attributed to Schaan, A. P..

4 recordsLinked to original sources

bioRxiv2026

Blautia wexlerae Transforms Dietary Fatty Acids to Activate Enteroendocrine Signaling and Improve Metabolic Health in Mice and Humans

Metabolites produced by the gut microbiome influence host metabolic health, but how this occurs remains incompletely defined. Here, we report that a common human gut commensal, Blautia wexlerae, converts dietary fats into bioactive metabolites that induce gut hormone production to affect glucose metabolism and suppress appetite. We found that colonization with Blautia wexlerae correlated with healthier eating behaviors in humans. Blautia wexlerae encodes a unique acyl transferase and is capable of producing acyl amines from nutrient substrates. These Blautia acyl amines stimulated human enteroendocrine cells to secrete GLP-1 and other gut peptide hormones more potently than endogenously produced acyl amines. When fed to mice, acyl amines improved glycemic control and decreased appetite. In humans, higher stool levels of Blautia DNA encoding acyl amine synthesis genes correlated with leanness and decreased dietary fat intake. These results define a mechanism of action for how Blautia wexlerae affects host metabolic control.

microbiology↗

bioRxiv2025

Industrialization drives convergent microbial and physiological shifts in the human metaorganism

Understanding how host lifestyle and industrialization shape the human gut microbiome and intestinal physiology requires multimodal analyses across diverse global host contexts. Here, we generate multivariate data from the Global Microbiome Conservancy cohort, including gut microbiome, IgA-sequencing, host genotyping, diet, lifestyle and fecal biomarker profiles, to investigate host-microbiome interactions across gradients of industrialization and geography. We show that industrialization is associated with homogenized microbial compositions, reduced microbial diversity, and lower community stability, independent of host confounders. We further show that industrialization is linked to elevated markers of gut stress, increased IgA secretion, and altered patterns of IgA-bacteria interactions. Finally, we show that microbiome-based disease predictors trained on industrialized populations lose accuracy in less industrialized cohorts, highlighting limited cross-population transferability. Together, our results suggest profound restructuring of host-microbiome interactions due to industrialized lifestyles, and emphasize the need for inclusive, globally representative data to improve translational microbiome applications across diverse human populations.

microbiology↗

bioRxiv2024

Gut microbiota and type 2 diabetes associations: A meta-analysis of 16s studies and their methodological challenges

Diabetes mellitus is a prevalent chronic non-communicable disease, and recent studies have explored the link between gut microbiota and its development. Despite some evidence suggesting an association, the influence of gut microbiota on type 2 diabetes DM2 remains unclear. A systematic search of PubMed Janeiro 2016- 10 December 2023 using the keywords "16S" and "diabetes" or "DM2" and "gut microbiota" and "diabetes" or "DM2". The studies included compared gut microbiome diversity between diabetic and non-diabetic adults using 16S rRNA sequencing, excluding children, interventions, and type 1 diabetes. Alpha diversity indices and bacterial mean abundance were analyzed, with statistical assessments using a random-effects model and I2 for heterogeneity. Thirteen studies met the criteria, with the Shannon index being the most commonly used measure. Results showed significant heterogeneity I2 > 75% and no notable differences between diabetic and non-diabetic groups. Other indices, such as Chao1 and phylogenetic whole tree, similarly showed no consistent differences. Taxonomic analysis also failed to find phyla consistently correlated with DM2, with variability across studies. The relationship between gut microbiota and diabetes remains uncertain due to technical and biological factors that are often overlooked. The inconsistencies across studies highlight the low reproducibility common in microbiota research.

bioinformatics↗

bioRxiv2023

Temporal dynamics of gut microbiomes in non-industrialized urban Amazonia

BackgroundIncreasing levels of industrialization have been associated with changes in gut microbiome structure and loss of features thought to be crucial for maintaining gut ecological balance. The stability of gut microbial communities over time within individuals seems to be largely affected by this transition but has been overlooked among transitioning populations from low to middle-income countries. Here, we used shotgun sequencing to characterize the temporal dynamics of gut microbiomes of 24 individuals living in an urban non-industrialized lifestyle in the Brazilian Amazon and contextualized our data with 165 matching longitudinal samples from an urban industrialized and a rural non-industrialized population. ResultsWe show that gut microbiome composition and diversity have greater variability over time among non-industrialized individuals when compared to industrialized counterparts and that taxa may present diverse temporal dynamics across human populations. Enterotype classifications show community types are generally stable over time despite shifts in microbiome structure. Further, by tracking genomes over time, we show that levels of bacterial population replacements are more frequent among Amazonian individuals and non-synonymous variants accumulate in genes associated with degradation of host dietary polysaccharides. ConclusionsOur results suggest that the stability of gut microbiomes is influenced by levels of industrialization and that tracking microbial population dynamics is important to understand how the microbiome will adapt to these transitions.

microbiology↗