title: Production of ammonia by Tritrichomonas foetus and Trichomonas vaginalis.
abstract: Production of ammonia is difficult to find among the various studies of amino acid metabolism in protozoa. Several studies suggest that catabolism of arginine to ammonium is important for the growth of trichomonads. Trichomonads are amitochondriate zooflagellates that thrive under microaerophilic and anaerobic conditions. The authors were able to detect accumulation of ammonium ions and ammonia in cultures of Tritrichomonas foetus and Trichomonas vaginalis, including those resistant to metronidazole. Ammonium ions and ammonia were detected using the indophenol colorimetric method. Cells incubated overnight under an ambient oxygen gas phase had 0.9 mM soluble ammonium (NH(4)(+) and NH(3)) or a 20 % greater concentration of ammonium relative to sterile growth medium that had been incubated similarly. Production of ammonia itself was confirmed by analysis of a wick that was moistened with sulfuric acid (20 mM) and placed above the liquid in sealed cultures of a strain of Trichomonas vaginalis. The wicks from these cultures captured the equivalent of 0.048 mM volatile ammonia (NH(3)) from the liquid as compared to 0.021 mM volatile ammonia from sterile medium after overnight incubation. Intact trichomonads, 0.7 x 10(6) cells ml(-1) equivalent to 0.7 mg protein ml(-1), incubated in Doran's buffer with or without (1 mM) L-arginine produced significant amounts of soluble ammonium (0.07 mM and 0.04 mM, respectively) during 60 min. The results indicate that ammonium ions and the more irritating ammonia are significant metabolites of trichomonads. In addition, based upon end-product amounts, it appears that the rate of arginine metabolism is of the same order of magnitude as that for carbohydrate metabolism by trichomonads.
authors.affiliation: Haskins Laboratories, Pace University, New York, NY 10038, USA.
authors.forename: Yekaterina
authors.initials: Y
authors.lastname: Kleydman
authors.affiliation: Department of Chemistry and Physical Sciences, Pace University, New York, NY 10038, USA.|Haskins Laboratories, Pace University, New York, NY 10038, USA.
authors.forename: Nigel
authors.initials: N
authors.lastname: Yarlett
authors.affiliation: Department of Biology, Pace University, New York, NY 10038, USA.|Haskins Laboratories, Pace University, New York, NY 10038, USA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Gorrell
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D000818:Animals; D001120:Arginine / Q000378:metabolism; D003470:Culture Media; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D014246:Trichomonas vaginalis / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D016835:Tritrichomonas foetus / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism
chemical_list: D003470:Culture Media; D000644:Quaternary Ammonium Compounds; D000641:Ammonia; D001120:Arginine