AuthorZheng, Zhi-Ying, 1957-
KeywordsHealth Sciences, Nutrition.
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractBile acids have been implicated by epidemiologic evidence as causative agents in colon cancer. Previous studies have indicated that the bile acids damage DNA. However, the conjugated forms of bile acids (eg. tauro conjugates) have not been tested for interaction with DNA. The present study compared the DNA-damaging ability of unconjugated and conjugated bile acids using the E. coli SOS test system. The E. coli tester strain was incubated with the bile acids and conjugated bile acids. Both cell survival and induction of the SOS response was measured. Among unconjugated bile acids, deoxycholate, chenodeoxycholate, and lithocholic acid were confirmed as DNA damaging agents by a decrease in surviving fraction and increase of the fraction of blue colonies undergoing SOS induction with increasing doses. Cholate, however, did not cause DNA damage by these criteria. Among the conjugated bile acids, taurochenodeoxycholate caused as much DNA damage as chenodeoxycholate. Taurodeoxycholate caused DNA damage, but had less of an effect than deoxycholate. Taurocholate and taurolithocholate failed to show a DNA damaging effect.
Degree ProgramGraduate College
Nutrition and Food Science