The gut-brain axis is a bidirectional communication system between the central nervous system and the gastrointestinal tract, in which serotonin (5-HT) functions as a key neurotransmitter. Recent research has increasingly concentrated on tryptophan, the precursor to 5-HT and on the microbial regulation of tryptophan metabolism, with an emphasis on host-microbe control over kynurenine pathway metabolism and microbial-specific pathways that generate bioactive tryptophan metabolites. Here, we critically assess recent progress made towards a mechanistic understanding of the microbial regulation of tryptophan metabolism and microbiota-gut-brain axis homeostasis highlighting the role tryptophan metabolism plays in preclinical and clinical neuroscience and in the challenge to improve our understanding of how perturbed tryptophan metabolism contributes to stress-related psychiatric disorders.

中文翻译：

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专注于基本要素：色氨酸代谢和微生物组-肠脑轴。

肠脑轴是中枢神经系统和胃肠道之间的双向通讯系统，其中5-羟色胺（5-HT）充当关键的神经递质。最近的研究越来越集中于色氨酸，5-HT的前体和色氨酸代谢的微生物调控，重点是宿主微生物对犬尿氨酸途径代谢和产生生物活性色氨酸代谢产物的微生物特异性途径的控制。这里，