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An In Vitro Batch-culture Model to Estimate the Effects of Interventional Regimens on Human Fecal Microbiota
Published on: July 31, 2019
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Intestinal bacteria-derived tryptamine and its impact on human gut microbiota.
Nize Otaru1,2, Anna Greppi1, Serafina Plüss1
1Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland.
Frontiers in Microbiomes
|March 19, 2026
Summary
Gut bacteria produce tryptamine, impacting gut homeostasis. This study identified new producers, found tryptamine affects gut microbiota composition and function, and noted specific bacterial sensitivities.
Area of Science:
- Microbiology
- Gut Microbiome Research
- Metabolomics
Background:
- Tryptamine, a neuromodulator from tryptophan, influences gut homeostasis via microbial production.
- Limited knowledge exists on tryptamine-producing bacteria, regulatory factors, and its community-level effects.
Purpose of the Study:
- Characterize tryptamine production kinetics in intestinal strains.
- Investigate tryptamine's role in acid stress tolerance.
- Assess tryptamine's impact on gut microbiota composition and function ex vivo.
Main Methods:
- Screened 13 intestinal strains for tryptamine production.
- Conducted 48-hour ex vivo fecal batch fermentations with human gut microbiota.
- Performed in vitro growth assays of 18 intestinal strains exposed to tryptamine.
Main Results:
- Identified five tryptamine-producing taxa, including Ruminococcus gnavus.
- Tryptamine production increased with tryptophan levels but was not linked to acid tolerance.
- Ex vivo exposure to 2.4 mM tryptamine altered microbiota function (carbohydrate consumption) and composition (reduced Bacteroidota, Bacteroides, Blautia, Faecalibacterium).
- In vitro studies confirmed sensitivity of Bacteroides and Faecalibacterium to tryptamine.
Conclusions:
- Intestinal bacteria-derived tryptamine is a bioactive molecule modulating gut microbial communities.
- Tryptamine impacts gut homeostasis and microbial physiology, with specific inhibitory effects on certain bacteria.
- Further research is needed to elucidate the precise mechanisms of tryptamine's microbial interactions.
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