Studies of Sulfur Reduction of Taurine and Taurine-Conjugated Bile Acids by Bile acid 7α-Dehydroxylating Bacteria
type: CreativeWork
description: Bile acids are C24 steroids that are derived in the liver from cholesterol and secreted into the intestinal lumen to aid in emulsification of dietary lipids and lipid-soluble vitamins. The indigenous intestinal microflora modify bile acids, producing up to 20 unique bile acid metabolites. The 7α-dehydroxylation of the bile acids is the most physiologically important bile acid biotransformation. All known intestinal bacteria capable of bile acid 7α-dehydroxylation are anaerobic, gram-positive rods of the genera Clostridium and Eubcicterium. Bile acid 7α-dehydroxylating bacteria often contain bile salt hydrolase, which hydrolyzes the peptide bond in taurine-conjugated bile acids to yield a free bile acid and taurine. Taurine is an organosulfonate containing a sulfite moiety. There have been no published reports indicating whether 7α-dehydroxylating bacteria can utilize taurine. Given that taurine and taurine-conjugated bile acids are found at great concentrations in the intestine, the ability to utilize the compound would confer a competitive advantage to these bacteria. In this study, the ability of 7α-dehydroxylating bacteria to dissimilate taurine and taurine-conjugated bile acids produce hydrogen sulfide was investigated. First, hydrogen sulfide produced by bile acid 7α-dehydroxylating bacteria cultured in tryptic soy broth and semi-defined media from taurine and taurine-conjugated bile acids was qualitatively detected by inclusion of ferric ammonium citrate in the media. The results obtained from trials utilizing anaerobic tryptic soy broth and from semi-defined medium were not consistent, suggesting that qualitative determination of sulfide by inclusion of ferric ammonium citrate is inconclusive. Then hydrogen sulfide produced by bile acid 7α-dehydroxylating bacteria cultured in modified semi-defined medium (not containing a reducing agent) over time in the presence or absence of taurine-conjugated bile acids was quantified using the methylene blue method. Sulfi…
abstract: Bile acids are C24 steroids that are derived in the liver from cholesterol and secreted into the intestinal lumen to aid in emulsification of dietary lipids and lipid-soluble vitamins. The indigenous intestinal microflora modify bile acids, producing up to 20 unique bile acid metabolites. The 7α-dehydroxylation of the bile acids is the most physiologically important bile acid biotransformation. All known intestinal bacteria capable of bile acid 7α-dehydroxylation are anaerobic, gram-positive rods of the genera Clostridium and Eubcicterium. Bile acid 7α-dehydroxylating bacteria often contain bile salt hydrolase, which hydrolyzes the peptide bond in taurine-conjugated bile acids to yield a free bile acid and taurine. Taurine is an organosulfonate containing a sulfite moiety. There have been no published reports indicating whether 7α-dehydroxylating bacteria can utilize taurine. Given that taurine and taurine-conjugated bile acids are found at great concentrations in the intestine, the ability to utilize the compound would confer a competitive advantage to these bacteria. In this study, the ability of 7α-dehydroxylating bacteria to dissimilate taurine and taurine-conjugated bile acids produce hydrogen sulfide was investigated. First, hydrogen sulfide produced by bile acid 7α-dehydroxylating bacteria cultured in tryptic soy broth and semi-defined media from taurine and taurine-conjugated bile acids was qualitatively detected by inclusion of ferric ammonium citrate in the media. The results obtained from trials utilizing anaerobic tryptic soy broth and from semi-defined medium were not consistent, suggesting that qualitative determination of sulfide by inclusion of ferric ammonium citrate is inconclusive. Then hydrogen sulfide produced by bile acid 7α-dehydroxylating bacteria cultured in modified semi-defined medium (not containing a reducing agent) over time in the presence or absence of taurine-conjugated bile acids was quantified using the methylene blue method. Sulfi…
author: Qian, Jiang
keywords: Chemistry
date published: 2000-08-01T07:00:00Z
date modified: 2026-07-24T06:07:42Z
provider: Western Kentucky University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Western Kentucky University