First, it was confirmed that the number of bacterial genes involved in the metabolism of bile acid increased in the intestinal tract of Hyakuju, and from the analysis of bile acid in the stool, the isoallo LCA metabolized by the intestinal bacteria increased significantly. I found that I was there.

　When the intestinal bacterial strain was isolated and the metabolic reaction was confirmed, Parabacteroides merdae, Odoribacter laneus, and Odoribacter aceae were identified as bacterial strains capable of effectively synthesizing isoallo LCA.We also found that administration of Odoribacter aceae to sterile mice can synthesize isoallo LCA in vivo.

　In the genome decoding of these bacterial strains, it is considered that they have an enzyme homologous to human 5α-reductase (5AR) in common, and that they are involved in bile acid metabolism adjacent to the 5AR gene. It was found that there is a 5βHSDH (3beta hydroxide steroid reductase) gene. The synthetic pathway was also revealed, such as the lack of 3AR and 5βHSDH resulting in the absence of biosynthesis to isoallo LCA.

　Furthermore, since bile acids have been shown to have an inhibitory effect on the growth of pathogenic bacteria, it was examined whether isoallo LCA has a similar effect.As a result, it was found that it has a strong antibacterial activity against gram-positive pathogenic bacteria, which has become a problem in hospital-acquired infections in recent years.

　This suggests that the elimination of gram-positive pathogenic bacteria is promoted in the intestines of centenarians, and that a healthy intestinal environment may be maintained. The intestinal bacterial strain that synthesizes isoalloLCA has the potential to be applied to the prevention and treatment of infectious diseases.

Paper information:[Nature] Novel bile acid biosynthetic pathways are enriched in the microbiome of centenarians