Analysis of the interaction between two key gut microbes under deoxycholic acid (DCA) stress suggests that metabolic cooperation enhances resistance to bile acid stress and may contribute to gut microbiome resilience, with potential relevance to liver- and bile acid-related disorders.
Abstract
Although bile acid-mediated microbiome-host interactions are known to shape gut microbial composition and function, the mechanisms by which bile acid stress influences microbial metabolic interactions remain poorly understood. Here, we investigated the interaction between two key gut microbes, Bacteroides thetaiotaomicron and Collinsella aerofaciens, under deoxycholic acid (DCA) stress. In anaerobic coculture, C. aerofaciens mitigated the inhibitory effects of DCA on B. thetaiotaomicron, primarily through DCA uptake from the medium, as confirmed by DCA quantification. Proteomic analysis showed that DCA broadly disrupted amino acid and vitamin metabolism, particularly in B. thetaiotaomicron. In contrast, coculture promoted widespread metabolic activation in C. aerofaciens, including enhanced vitamin B6 metabolism and increased production of citrulline and ornithine. These findings suggest that metabolic cooperation enhances resistance to bile acid stress and may contribute to gut microbiome resilience, with potential relevance to liver- and bile acid-related disorders.
BACKGROUND
Bacteroides fragilis is a dominant member of the human intestinal microbiota and is known for its ecological plasticity and capacity to persist under fluctuating intestinal conditions. Bile salts are abundant host-derived molecules that act not only as antimicrobial agents but also as environmental cues shaping bacterial adaptation in the gut.
OBJECTIVES
This study investigated how B. fragilis adapts to bile salts at physiological, structural, and metabolic levels.
METHODS
A panel of clinical and commensal strains was evaluated for bile tolerance. The B. fragilis type strain ATCC 25285 was selected for in-depth analyses of biofilm formation, extracellular matrix composition, antimicrobial tolerance, and mucin translocation.
RESULTS
Clinical isolates showed high bile tolerance, with MIC values up to 14% (w/v). Bile exposure promoted biofilm formation, particularly in the presence of glucose and mucin-derived carbohydrates, resulting in thick, protein-rich extracellular matrices. Biofilms formed under bile conditions displayed increased tolerance to Metronidazole and the antimicrobial peptide LL-37. Bile salts also significantly reduced bacterial translocation across a mucin layer.
CONCLUSIONS
Our results support a multilayered adaptive model in which bile salts act as environmental cues that reshape B. fragilis physiology, enhancing fitness, persistence, and host interactions while favoring luminal colonization.
Clara Maria Guimarães Silva, Caroline Evangelista Nogueira dos Santos, Marlei Gomes et al.· Anaerobe· 0 citations
In vitro data demonstrate enhanced probiotic metabolite production and suggest potential neuroprotective relevance, supporting future confirmatory in vivo investigations.
M. Praveen, Long Yu, Caterina Selva et al.· Food Chemistry· 0 citations
The gut microbiome and its metabolites are vitally important for host dietary digestion, nutrient absorption, and energy metabolism. Yellowfin tuna (Thunnus albacares), a large warm‐blooded fish that sustains continuous high‐speed swimming, demonstrates higher energy demands than other fish. However, there are no relevant reports on the functional contribution of specialized gut microbiota to energy homeostasis of tuna. To bridge this knowledge gap, we characterized the function of a new bacterial strain, Acinetobacter seifertii YFT067, derived from the intestine of wild yellowfin tuna. According to whole genome sequencing, YFT067 exhibited the probiotic potential with a high ability in nutrient metabolism. In vitro test demonstrated that YFT067 is tolerant to the simulated gastroenteric juice and strong in adhesion. The six‐week zebrafish feeding trial with 108 CFU/g YFT067 strain supplementation significantly enhanced body growth, feed conversion, and digestive enzyme activity of the host as well as the intestinal health, including enhanced goblet cells number and short‐chain fatty acids (propionate, butyrate, and valerate) contents. Transcriptomic analysis revealed that the digestive system and metabolism process were significantly up‐regulated with fabp, fatp4, mgat3a, acat1, apoa1b, and apoa4a enriched in the fat digestive and absorption pathway and pltp, cetp, and nceh1a enriched in the cholesterol metabolism pathway. These findings indicated A. seifertii YFT067 as a promising probiotic candidate for enhancing tuna farming production through improving metabolic efficiency and intestinal health. Our study provides foundational evidence for developing YFT067‐based probiotic formulations to optimize growth performance and cultivation sustainability in tuna aquaculture.
Ying Zou, Hai Huang, Qiongyao Fu et al.· 4 citations
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