title: An antibiotic-free medium for the xenic cultivation of Entamoeba gingivalis.
abstract: Diamond's TYI-S-33 (Trypticase-Yeast Extract-Iron-Serum) medium was used as the basis for a new antibiotic-free medium for xenic growth of Entamoeba gingivalis. Nutritional requirements of the oral protozoan were determined in an effort to optimize growth. TYI-S-33 medium did not support E. gingivalis growth prior to modification. The changes included: (a) deletion of L-cysteine.HCl and thioctic acid, (b) substitution of glucose for dextran I (mol. wt 185,000) or rice starch, (c) reduction of concentrations of tryptone (2.5 g l-1), yeast extract (1.25 g l-1) and dextran I (1 g l-1), (d) increased concentration of ferric ammonium citrate (0.2 g l-1), and (e) addition of gastric mucin (2.4 g l-1). Dextran I was chosen as the major carbon source; its use in the medium limited growth of accompanying bacteria. This new antibiotic-free medium significantly increased E. gingivalis growth (16-20 E. gingivalis trophozoites observed per field) as compared to growth in Diamond's TYSGM-9 (Trypticase-Yeast Extract-Serum-Gastric Mucin) medium (six to 10 E. gingivalis trophozoites observed per field).
authors.affiliation: Department of Microbiology, New York University Dental Center, NY 10010.
authors.forename: J T
authors.initials: JT
authors.lastname: Gannon
authors.forename: H A
authors.initials: HA
authors.lastname: Linke
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002951:Citrates / Q000494:pharmacology; D019343:Citric Acid; D003470:Culture Media / Q000737:chemistry / Q000494:pharmacology*; D003911:Dextrans / Q000494:pharmacology; D004747:Entamoeba / Q000254:growth & development* / Q000378:metabolism; D005752:Gastric Mucins / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D010461:Peptones / Q000494:pharmacology; D008063:Thioctic Acid / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D002951:Citrates; D003470:Culture Media; D003911:Dextrans; D005752:Gastric Mucins; D010461:Peptones; D019343:Citric Acid; C001830:tryptones; D008063:Thioctic Acid; D005947:Glucose