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Keywords

adhesive colonization; gut microbiota; mucus layers; oxygen availability

Abstract

The gut microbiota plays a crucial role in host digestion and immune regulation; however, most existing research relies on fecal sampling, leaving uncertainty regarding whether fecal microbiota can accurately reflect the symbiotic microbial components at distinct gut sites. To address this gap, this study employed 16S rRNA gene sequencing to systematically analyze the microbial composition of three spatial compartments in the rat colon: luminal contents, mucus layer, and epithelial tissue. The results revealed notable differences in microbial communities across the three compartments. The luminal contents, which were closely associated with the fecal microbiota, exhibited high microbial abundance, encompassing gram-positive bacteria, gram-negative bacteria, aerobic bacteria, and obligate anaerobes. By contrast, the mucus layer and epithelial tissue were predominantly enriched in gram-negative bacteria and obligate anaerobes, with a marked scarcity of aerobic bacteria. Further analysis indicated that the ACE and Chao1 indices were significantly higher in mucus samples than in luminal samples, whereas tissue samples showed reduced richness but relatively stable diversity. Additionally, Proteobacteria were rarely detected in the lumen but were significantly enriched in the mucus and tissue. These findings suggest that the oxygen content in the intestinal lumen is significantly higher than that of the host-derived mucus layer and epithelial tissue and that this oxygen gradient drives the spatial partitioning of the gut microbiota. Collectively, this study clarifies the spatial distribution characteristics of the gut microbiota and highlights oxygen availability as a key factor in regulating microbial adhesion and colonization

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Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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