title: Formation of hyodeoxycholic acid from muricholic acid and hyocholic acid by an unidentified gram-positive rod termed HDCA-1 isolated from rat intestinal microflora.
abstract: From the rat intestinal microflora we isolated a gram-positive rod, termed HDCA-1, that is a member of a not previously described genomic species and that is able to transform the 3alpha,6beta, 7beta-trihydroxy bile acid beta-muricholic acid into hyodeoxycholic acid (3alpha,6alpha-dihydroxy acid) by dehydroxylation of the 7beta-hydroxy group and epimerization of the 6beta-hydroxy group into a 6alpha-hydroxy group. Other bile acids that were also transformed into hyodeoxycholic acid were hyocholic acid (3alpha, 6alpha,7alpha-trihydroxy acid), alpha-muricholic acid (3alpha,6beta, 7alpha-trihydroxy acid), and omega-muricholic acid (3alpha,6alpha, 7beta-trihydroxy acid). The strain HDCA-1 could not be grown unless a nonconjugated 7-hydroxylated bile acid and an unidentified growth factor produced by a Ruminococcus productus strain that was also isolated from the intestinal microflora were added to the culture medium. Germfree rats selectively associated with the strain HDCA-1 plus a bile acid-deconjugating strain and the growth factor-producing R. productus strain converted beta-muricholic acid almost completely into hyodeoxycholic acid.
authors.affiliation: Rega Institute for Medical Research, Katholieke Universiteit Leuven, Leuven, Belgium.
authors.forename: H J
authors.initials: HJ
authors.lastname: Eyssen
authors.forename: G
authors.initials: G
authors.lastname: De Pauw
authors.forename: J
authors.initials: J
authors.lastname: Van Eldere
mesh_terms: D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism; D002793:Cholic Acids / Q000378:metabolism*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D003840:Deoxycholic Acid / Q000378:metabolism*; D020459:Genes, rRNA; D005856:Germ-Free Life; D016987:Gram-Positive Rods / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D007422:Intestines / Q000382:microbiology*; D051379:Mice; D008855:Microscopy, Electron, Scanning; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D051381:Rats; D017422:Sequence Analysis, DNA
chemical_list: D001647:Bile Acids and Salts; D002793:Cholic Acids; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D003840:Deoxycholic Acid; C004821:muricholic acid; C010471:hyodeoxycholic acid