title: Metabolic profiling of yeast culture using gas chromatography coupled with orthogonal acceleration accurate mass time-of-flight mass spectrometry: application to biomarker discovery.
abstract: Yeast and yeast cultures are frequently used as additives in diets of dairy cows. Beneficial effects from the inclusion of yeast culture in diets for dairy mammals have been reported, and the aim of this study was to develop a comprehensive analytical method for the accurate mass identification of the 'global' metabolites in order to differentiate a variety of yeasts at varying growth stages (Diamond V XP, Yea-Sacc and Levucell). Microwave-assisted derivatization for metabolic profiling is demonstrated through the analysis of differing yeast samples developed for cattle feed, which include a wide range of metabolites of interest covering a large range of compound classes. Accurate identification of the components was undertaken using GC-oa-ToFMS (gas chromatography-orthogonal acceleration-time-of-flight mass spectrometry), followed by principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) for data reduction and biomarker discovery. Semi-quantification (fold changes in relative peak areas) was reported for metabolites identified as possible discriminative biomarkers (p-value <0.05, fold change >2), including D-ribose (four fold decrease), myo-inositol (five fold increase), L-phenylalanine (three fold increase), glucopyranoside (two fold increase), fructose (three fold increase) and threitol (three fold increase) respectively.
authors.affiliation: School of Applied Sciences, R.M.I.T. University, GPO Box 2476, Melbourne, Victoria 3001, Australia.
authors.forename: Elsuida
authors.initials: E
authors.lastname: Kondo
authors.affiliation: Centre for Green Chemistry, School of Chemistry, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Marriott
authors.affiliation: School of Applied Sciences, R.M.I.T. University, GPO Box 2476, Melbourne, Victoria 3001, Australia.
authors.forename: Rhiannon M
authors.initials: RM
authors.lastname: Parker
authors.affiliation: Department of Molecular Biology, Umea University, SE-901 87 Umea, Sweden.
authors.forename: Konstantinos A
authors.initials: KA
authors.lastname: Kouremenos
authors.affiliation: School of Applied Sciences, R.M.I.T. University, GPO Box 2476, Melbourne, Victoria 3001, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Morrison
authors.affiliation: School of Applied Sciences, R.M.I.T. University, GPO Box 2476, Melbourne, Victoria 3001, Australia. Electronic address: mike.adams@rmit.edu.au.
authors.forename: Mike
authors.initials: M
authors.lastname: Adams
mesh_terms: D015415:Biomarkers / Q000032:analysis*; D016002:Discriminant Analysis; D008401:Gas Chromatography-Mass Spectrometry; D007294:Inositol / Q000737:chemistry / Q000378:metabolism; D016018:Least-Squares Analysis; D059625:Liquid-Liquid Extraction; D055442:Metabolome; D008872:Microwaves; D010649:Phenylalanine / Q000737:chemistry / Q000378:metabolism; D025341:Principal Component Analysis; D012266:Ribose / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D010649:Phenylalanine; D007294:Inositol; D012266:Ribose
keywords: Accurate mass time-of-flight mass spectrometry; Biomarkers; Gas chromatography; Metabolic profiling; Metabolomics; Yeast culture