title: Major Anaerobic Bacteria Responsible for the Production of Carcinogenic Acetaldehyde from Ethanol in the Colon and Rectum.
abstract: OBJECTIVE
  The importance of ethanol oxidation by intestinal aerobes and facultative anaerobes under aerobic conditions in the pathogenesis of ethanol-related colorectal cancer has been proposed. However, the role of obligate anaerobes therein remains to be established, and it is still unclear which bacterial species, if any, are most important in the production and/or elimination of carcinogenic acetaldehyde under such conditions. This study was undertaken to address these issues.
  
  
  METHODS
  More than 500 bacterial strains were isolated from the faeces of Japanese alcoholics and phylogenetically characterized, and their aerobic ethanol metabolism was studied in vitro to examine their ability to accumulate acetaldehyde beyond the minimum mutagenic concentration (MMC, 50 µM).
  
  
  RESULTS
  Bacterial strains that were considered to potentially accumulate acetaldehyde beyond the MMC under aerobic conditions in the colon and rectum were identified and referred to as 'potential acetaldehyde accumulators' (PAAs). Ruminococcus, an obligate anaerobe, was identified as a genus that includes a large number of PAAs. Other obligate anaerobes were also found to include PAAs. The accumulation of acetaldehyde by PAAs colonizing the colorectal mucosal surface could be described, at least in part, as the response of PAAs to oxidative stress.
  
  
  CONCLUSIONS
  Ethanol oxidation by intestinal obligate anaerobes under aerobic conditions in the colon and rectum could also play an important role in the pathogenesis of ethanol-related colorectal cancer.
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan.
authors.forename: Atsuki
authors.initials: A
authors.lastname: Tsuruya
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan.
authors.forename: Akika
authors.initials: A
authors.lastname: Kuwahara
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Saito
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan.
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Yamaguchi
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan.
authors.forename: Natsuki
authors.initials: N
authors.lastname: Tenma
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Inai
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Suntory World Research Center, Suntory Holdings Ltd., Soraku-gun, Kyoto 619-0284, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Tsutsumi
authors.affiliation: Suntory World Research Center, Suntory Holdings Ltd., Soraku-gun, Kyoto 619-0284, Japan.
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Suwa
authors.affiliation: Division of Carcinogenesis & Cancer Prevention, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Totsuka
authors.affiliation: Center for Omics and Bioinformatics, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Suda
authors.affiliation: Center for Omics and Bioinformatics, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan.
authors.forename: Kenshiro
authors.initials: K
authors.lastname: Oshima
authors.affiliation: Center for Omics and Bioinformatics, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan.
authors.forename: Masahira
authors.initials: M
authors.lastname: Hattori
authors.affiliation: National Hospital Organization Kurihama Medical and Addiction Center, Yokosuka, Kanagawa 239-0841, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Mizukami
authors.affiliation: National Hospital Organization Kurihama Medical and Addiction Center, Yokosuka, Kanagawa 239-0841, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Yokoyama
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan.
authors.forename: Takefumi
authors.initials: T
authors.lastname: Shimoyama
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan nakayama@seika.che.tohoku.ac.jp.
authors.forename: Toru
authors.initials: T
authors.lastname: Nakayama
mesh_terms: D000079:Acetaldehyde / Q000378:metabolism*; D001421:Bacteria, Anaerobic / Q000378:metabolism*; D003106:Colon / Q000382:microbiology*; D000431:Ethanol / Q000378:metabolism*; D005243:Feces / Q000382:microbiology; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction; D010802:Phylogeny; D017382:Reactive Oxygen Species / Q000378:metabolism; D012007:Rectum / Q000382:microbiology*; D045857:Ruminococcus / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D000431:Ethanol; D000079:Acetaldehyde