title: The strict anaerobic gut microbe Eubacterium hallii transforms the carcinogenic dietary heterocyclic amine 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP).
abstract: 2-Amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP) is the most abundant food-derived heterocyclic aromatic amine in well-cooked meats and may contribute to the recognized carcinogenicity of processed meats. In this study, a panel of human gut microbes was tested for their ability to convert PhIP to a conjugate PhIP-M1. Eubacterium hallii was newly identified to catalyse the conversion of PhIP to PhIP-M1 with high efficiency. The reaction was shown to involve the metabolism of glycerol to 3-hydroxypropionaldehyde as a key pathway. The proficiency of E. hallii in transforming PhIP in the presence of a complex intestinal microbiota was confirmed using batch fermentations inoculated with effluents from a continuous intestinal fermentation model mimicking human proximal and distal colon microbiota. In batch fermentations inoculated with proximal colon microbiota, PhIP-M1 transformation corresponded to an up to 300-fold increase of E. hallii. In contrast, PhIP transformation of distal colon microbiota was low but increased by 120-fold after supplementation with E. hallii. These findings indicate for the first time the relevance of the abundant commensal strict anaerobe E. hallii in the transformation of a dietary carcinogen that could contribute to its detoxification in the human colon.
authors.affiliation: Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.
authors.forename: Mostafa I
authors.initials: MI
authors.lastname: Fekry
authors.affiliation: Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.
authors.forename: Christina
authors.initials: C
authors.lastname: Engels
authors.affiliation: Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.
authors.forename: Clarissa
authors.initials: C
authors.lastname: Schwab
authors.affiliation: Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.
authors.forename: Christophe
authors.initials: C
authors.lastname: Lacroix
authors.affiliation: Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.
authors.forename: Shana J
authors.initials: SJ
authors.lastname: Sturla
authors.affiliation: Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.
authors.forename: Christophe
authors.initials: C
authors.lastname: Chassard
mesh_terms: D000693:Anaerobiosis; D001711:Biotransformation; D002273:Carcinogens / Q000378:metabolism*; D005051:Eubacterium / Q000378:metabolism*; D005285:Fermentation; D000069196:Gastrointestinal Microbiome; D041981:Gastrointestinal Tract / Q000382:microbiology*; D005985:Glyceraldehyde / Q000031:analogs & derivatives / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism; D006801:Humans; D007093:Imidazoles / Q000378:metabolism*; D064307:Microbiota; D008954:Models, Biological; D011407:Propane / Q000378:metabolism
chemical_list: D002273:Carcinogens; D007093:Imidazoles; C047158:3-hydroxypropionaldehyde; D005985:Glyceraldehyde; C049584:2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine; D005990:Glycerol; D011407:Propane