title: Carbohydrate and amino acid metabolism of Spironucleus vortens.
abstract: The metabolism of Spironucleus vortens, a parasitic, diplomonad flagellate related to Giardia intestinalis, was investigated using a combination of membrane inlet mass spectrometry, (1)H NMR, (13)C NMR, bioscreen continuous growth monitoring, and ion exchange chromatography. The products of glucose-fuelled and endogenous metabolism were identified by (1)H NMR and (13)C NMR as ethanol, acetate, alanine and lactate. Mass spectrometric monitoring of gas metabolism in buffered cell suspensions showed that glucose and ethanol could be used by S. vortens as energy-generating substrates, but bioscreen automated monitoring of growth in culture medium, as well as NMR analyses, suggested that neither of these compounds are the substrates of choice for this organism. Ion-exchange chromatographic analyses of free amino-acid and amino-acid hydrolysate of growth medium revealed that, despite the availability of large pools of free amino-acids in the medium, S. vortens hydrolysed large amounts of proteins during growth. The organism produced alanine and aspartate, and utilised lysine, arginine, leucine, cysteine and urea. However, mass spectrometric and bioscreen investigations showed that addition of the utilised amino acids to diluted culture medium did not induce any significant increase in metabolic or growth rates. Moreover, as no significant amounts of ornithine were produced, and addition of arginine under aerobic conditions did not generate NO production, there was no evidence of the presence of an energy-generating, arginine dihydrolase pathway in S. vortens under in vitro conditions.
authors.affiliation: School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK. MilletCO@gmail.com
authors.forename: Coralie O M
authors.initials: CO
authors.lastname: Millet
authors.forename: David
authors.initials: D
authors.lastname: Lloyd
authors.forename: Michael P
authors.initials: MP
authors.lastname: Coogan
authors.forename: Joanna
authors.initials: J
authors.lastname: Rumsey
authors.forename: Joanne
authors.initials: J
authors.lastname: Cable
mesh_terms: D000596:Amino Acids / Q000032:analysis / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D002247:Carbon Isotopes; D002852:Chromatography, Ion Exchange; D003470:Culture Media / Q000737:chemistry; D016828:Diplomonadida / Q000254:growth & development / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D017942:Nitric Acid / Q000378:metabolism; D010101:Oxygen Consumption; D053058:Trophozoites / Q000378:metabolism
chemical_list: D000596:Amino Acids; D002247:Carbon Isotopes; D003470:Culture Media; D002245:Carbon Dioxide; D017942:Nitric Acid; D006859:Hydrogen