Effects of Beta-Glucuronidase-Deficient and Lycopene-Producing Escherichia Coli Strains on Formation of Azoxymethane-Induced Aberrant Crypt Foci in the Rat Colon

Biochem Biophys Res Commun. 1999 Aug 27;262(2):322-7. doi: 10.1006/bbrc.1999.1199.


We tried to inhibit the formation of azoxymethane-induced aberrant crypt foci (ACF) in the rat intestine by feeding a culture of a beta-glucuronidase-deficient Escherichia coli strain or a cell suspension of a lycopene-producing E. coli strain. Feeding of the former culture to F344 rats did not decrease fecal beta-glucuronidase activity or the number of ACF compared with the control beta-glucuronidase-proficient groups. However, a significant positive correlation between the fecal beta-glucuronidase activity and the ACF number was observed among groups treated with cultures of beta-glucuronidase-proficient and -deficient strains. In the group treated with lycopene-producing cells, the number of ACF was significantly lower than that in the control group. A vegetable juice containing a larger amount of lycopene than a cell suspension of the lycopene-producing E. coli also decreased the number of ACF to the same extent as a cell suspension of the lycopene-producing bacteria. These results suggest that feeding of the beta-glucuronidase-deficient E. coli is not very effective in preventing colon carcinogenesis, although activity of the fecal beta-glucuronidase is associated with AOM-induced ACF formation, and that lycopene-producing intestinal bacteria can effectively prevent colon carcinogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anticarcinogenic Agents / pharmacology
  • Azoxymethane / pharmacology*
  • Beverages
  • Carcinogens / pharmacology
  • Carotenoids / pharmacology*
  • Colon / pathology
  • Colonic Neoplasms / prevention & control*
  • Dietary Fats / pharmacology
  • Escherichia coli / physiology*
  • Feces / enzymology
  • Glucuronidase / deficiency*
  • Glucuronidase / genetics
  • Intestinal Mucosa / pathology*
  • Intestines / microbiology
  • Lycopene
  • Male
  • Rats
  • Rats, Inbred F344
  • Rectum / pathology
  • Vegetables


  • Anticarcinogenic Agents
  • Carcinogens
  • Dietary Fats
  • Carotenoids
  • Glucuronidase
  • Azoxymethane
  • Lycopene