Gut bacterial aromatic amine production: aromatic amino acid decarboxylase and its effects on peripheral serotonin production.

Colonic luminal aromatic amines have been historically considered to be derived from dietary source, especially fermented foods; however, recent studies indicate that the gut microbiota serves as an alternative source of these amines. Herein, we show that five prominent genera of Firmicutes , and ) have the ability to abundantly produce aromatic amines through the action of aromatic amino acid decarboxylase (AADC). cultivation of human fecal samples revealed that a significant positive correlation between copy number of and phenylethylamine (PEA) production.

Putrescine Production by KP 3-4 Isolated from Fermented Foods.

Polyamines are aliphatic hydrocarbons with terminal amino groups and are essential for biological activities. It has been reported that polyamines have health-promoting effects in animals, such as the extension of lifespan by polyamine intake. The identification of a high polyamine-producing bacterium from foods could lead to the development of a novel probiotic candidate.

Analysis of polyamine biosynthetic- and transport ability of human indigenous Bifidobacterium.

Unlabelled: Bifidobacteria are members of the human intestinal microbiota, being numerically dominant in the colon of infants, and also being prevalent in the large intestine of adults. In this study, we measured the concentrations of major polyamines (putrescine, spermidine, and spermine) in cells and culture supernatant of 13 species of human indigenous Bifidobacterium at growing and stationary phase. Except for Bifidobacterium bifidum and Bifidobacterium gallicum, 11 species contained spermidine and/or spermine when grown in Gifu-anaerobic medium (GAM).

Functional analysis of arginine decarboxylase gene speA of Bacteroides dorei by markerless gene deletion.

Polyamine concentrations in the intestine are regulated by their biosynthesis by hundreds of gut microbial species and these polyamines are involved in host health and disease. However, polyamine biosynthesis has not been sufficiently analyzed in major members of the human gut microbiota, possibly owing to a lack of gene manipulation systems. In this study, we successfully performed markerless gene deletion in Bacteroides dorei, one of the major members of the human gut microbiota.

Comprehensive analysis of polyamine transport and biosynthesis in the dominant human gut bacteria: Potential presence of novel polyamine metabolism and transport genes.

Recent studies have reported that polyamines in the colonic lumen might affect animal health and these polyamines are thought to be produced by gut bacteria. In the present study, we measured the concentrations of three polyamines (putrescine, spermidine, and spermine) in cells and culture supernatants of 32 dominant human gut bacterial species in their growing and stationary phases. Combining polyamine concentration analysis in culture supernatant and cells with available genomic information showed that novel polyamine biosynthetic proteins and transporters were present in dominant human gut bacteria.

Use of Gifu Anaerobic Medium for culturing 32 dominant species of human gut microbes and its evaluation based on short-chain fatty acids fermentation profiles.

Recently, a "human gut microbial gene catalogue," which ranks the dominance of microbe genus/species in human fecal samples, was published. Most of the bacteria ranked in the catalog are currently publicly available; however, the growth media recommended by the distributors vary among species, hampering physiological comparisons among the bacteria. To address this problem, we evaluated Gifu anaerobic medium (GAM) as a standard medium.