TY - JOUR

T1 - Carbohydrate and amino acid metabolism of the diplomonad parasite Spironucleus vortens

AU - Millet, Coralie

AU - Lloyd, David

AU - Coogan, Michael

AU - Rumsey, Joanna

AU - Cable, Joanne

PY - 2011

Y1 - 2011

N2 - The metabolism of Spironucleus vortens, a parasitic, diplomonad flagellate related to Giardia intestinalis, was investigated using a combination of membrane inlet mass spectrometry, 1H NMR, 13C NMR, bioscreen continuous growth monitoring, and ion exchange chromatography. The products of glucose-fuelled and endogenous metabolism were identified by 1H NMR and 13C 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.

AB - The metabolism of Spironucleus vortens, a parasitic, diplomonad flagellate related to Giardia intestinalis, was investigated using a combination of membrane inlet mass spectrometry, 1H NMR, 13C NMR, bioscreen continuous growth monitoring, and ion exchange chromatography. The products of glucose-fuelled and endogenous metabolism were identified by 1H NMR and 13C 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.

KW - Diplomonad

KW - Spironucleus

KW - Carbohydrate

KW - Amino acid

KW - Mass spectrometry

KW - NMR

U2 - 10.1016/j.exppara.2011.05.025

DO - 10.1016/j.exppara.2011.05.025

M3 - Journal article

VL - 129

SP - 17

EP - 26

JO - Experimental Parasitology

JF - Experimental Parasitology

SN - 0014-4894

IS - 1

ER -