title: 3-Methylindole production is regulated in Clostridium scatologenes ATCC 25775.
abstract: OBJECTIVE
  3-Methylindole (3-MI) is a degradation product of L-tryptophan and is both an animal waste malodorant and threat to ruminant health. Culture conditions influencing 3-MI production in Clostridium scatologenes ATCC 25775 were investigated.
  
  
  RESULTS
  Extracellular 3-MI levels in cells cultured in brain heart infusion (BHI) medium (pH 7.0) at 33 degrees C and 37 degrees C for 72 h were 907 +/- 38 and 834 +/- 121 micromol l(-1), respectively. Cells cultured in tryptone-yeast (TY) extract medium at 37 degrees C for 48 h produced 104 +/- 86 micromol l(-1) 3-MI; however, addition of 1 mmol l(-1) L-tryptophan failed to increase extracellular levels (113 +/- 50 micromol l(-1) 3-MI). Specific activity of indole acetic acid decarboxylase measured in BHI, TY and TY plus 1 mmol l(-1) tryptophan-grown cells displayed 35-, 33- and 76-fold higher levels than in semi-defined medium-grown cells.
  
  
  CONCLUSIONS
  When cultured in rich medium, at 33 degrees C or 37 degrees C and pH 7.0, Cl. scatologenes ATCC 25775 optimally produced 3-MI. Addition of L-tryptophan to medium did not lead to significant increases in extracellular 3-MI levels. Whole cell assays indicate growth in rich medium significantly up-regulated 3-MI production.
  
  
  CONCLUSIONS
  Information presented here may prove useful in understanding what factors influence 3-MI production in malodorous animal wastes.
authors.affiliation: Department of Biology, Western Kentucky University, 1906 College Heights Blvd., Bowling Green, KY 42101-1080, USA. Kinchel.Doerner@wku.edu
authors.forename: K C
authors.initials: KC
authors.lastname: Doerner
authors.forename: K L
authors.initials: KL
authors.lastname: Cook
authors.forename: B P
authors.initials: BP
authors.lastname: Mason
mesh_terms: D003013:Clostridium / Q000378:metabolism* / Q000502:physiology; D003470:Culture Media / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D012862:Skatole / Q000378:metabolism*; D013696:Temperature; D015854:Up-Regulation
chemical_list: D003470:Culture Media; D012862:Skatole