title: Effects of beta-glucuronidase-deficient and lycopene-producing Escherichia coli strains on formation of azoxymethane-induced aberrant crypt foci in the rat colon.
abstract: 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.
authors.affiliation: School of Medicine, University of Tokushima, 3-18-15 Kuramoto-cho, Tokushima-shi, Tokushima, 770-8503, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Arimochi
authors.forename: K
authors.initials: K
authors.lastname: Kataoka
authors.forename: T
authors.initials: T
authors.lastname: Kuwahara
authors.forename: H
authors.initials: H
authors.lastname: Nakayama
authors.forename: N
authors.initials: N
authors.lastname: Misawa
authors.forename: Y
authors.initials: Y
authors.lastname: Ohnishi
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology; D001397:Azoxymethane / Q000494:pharmacology*; D001628:Beverages; D002273:Carcinogens / Q000494:pharmacology; D002338:Carotenoids / Q000494:pharmacology*; D003106:Colon / Q000473:pathology; D003110:Colonic Neoplasms / Q000517:prevention & control*; D004041:Dietary Fats / Q000494:pharmacology; D004926:Escherichia coli / Q000502:physiology*; D005243:Feces / Q000201:enzymology; D005966:Glucuronidase / Q000172:deficiency* / Q000235:genetics; D007413:Intestinal Mucosa / Q000473:pathology*; D007422:Intestines / Q000382:microbiology; D000077276:Lycopene; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D012007:Rectum / Q000473:pathology; D014675:Vegetables
chemical_list: D016588:Anticarcinogenic Agents; D002273:Carcinogens; D004041:Dietary Fats; D002338:Carotenoids; D005966:Glucuronidase; D001397:Azoxymethane; D000077276:Lycopene