title: Mastitomics, the integrated omics of bovine milk in an experimental model of Streptococcus uberis mastitis: 3. Untargeted metabolomics.
abstract: Intramammary infection leading to bovine mastitis is the leading disease problem affecting dairy cows and has marked effects on the milk produced by infected udder quarters. An experimental model of Streptococcus uberis mastitis has previously been investigated for clinical, immunological and pathophysiological alteration in milk, and has been the subject of peptidomic and quantitative proteomic investigation. The same sample set has now been investigated with a metabolomics approach using liquid chromatography and mass spectrometry. The analysis revealed over 3000 chromatographic peaks, of which 690 were putatively annotated with a metabolite. Hierarchical clustering analysis and principal component analysis demonstrated that metabolite changes due to S. uberis infection were maximal at 81 hours post challenge with metabolites in the milk from the resolution phase at 312 hours post challenge being closest to the pre-challenge samples. Metabolic pathway analysis revealed that the majority of the metabolites mapped to carbohydrate and nucleotide metabolism show a decreasing trend in concentration up to 81 hours post-challenge whereas an increasing trend was found in lipid metabolites and di-, tri- and tetra-peptides up to the same time point. The increase in these peptides coincides with an increase in larger peptides found in the previous peptidomic analysis and is likely to be due to protease degradation of milk proteins. Components of bile acid metabolism, linked to the FXR pathway regulating inflammation, were also increased. Metabolomic analysis of the response in milk during mastitis provides an essential component to the full understanding of the mammary gland's response to infection.
authors.affiliation: Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Bearsden Road, Glasgow, G61 1QH, UK. david.eckersall@glasgow.ac.uk.
authors.forename: Funmilola Clara
authors.initials: FC
authors.lastname: Thomas
authors.affiliation: Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Bearsden Road, Glasgow, G61 1QH, UK. david.eckersall@glasgow.ac.uk and Glasgow Polyomics, College of Medical, Veterinary and Life Science, University of Glasgow, Glasgow, UK.
authors.forename: Manikhandan
authors.initials: M
authors.lastname: Mudaliar
authors.affiliation: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, UK.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Tassi
authors.affiliation: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, UK.
authors.forename: Tom N
authors.initials: TN
authors.lastname: McNeilly
authors.affiliation: Glasgow Polyomics, College of Medical, Veterinary and Life Science, University of Glasgow, Glasgow, UK and Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Burchmore
authors.affiliation: Glasgow Polyomics, College of Medical, Veterinary and Life Science, University of Glasgow, Glasgow, UK and Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK.
authors.forename: Karl
authors.initials: K
authors.lastname: Burgess
authors.affiliation: Glasgow Polyomics, College of Medical, Veterinary and Life Science, University of Glasgow, Glasgow, UK and Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, UK.
authors.forename: Pawel
authors.initials: P
authors.lastname: Herzyk
authors.affiliation: Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Bearsden Road, Glasgow, G61 1QH, UK. david.eckersall@glasgow.ac.uk and Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, UK.
authors.forename: Ruth N
authors.initials: RN
authors.lastname: Zadoks
authors.affiliation: Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Bearsden Road, Glasgow, G61 1QH, UK. david.eckersall@glasgow.ac.uk.
authors.forename: P David
authors.initials: PD
authors.lastname: Eckersall
mesh_terms: D000818:Animals; D015415:Biomarkers; D002417:Cattle; D002853:Chromatography, Liquid; D016000:Cluster Analysis; D005260:Female; D020869:Gene Expression Profiling; D013058:Mass Spectrometry; D008414:Mastitis, Bovine / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D053858:Metabolic Networks and Pathways; D055442:Metabolome; D055432:Metabolomics / Q000379:methods; D008892:Milk / Q000378:metabolism*; D025341:Principal Component Analysis; D013290:Streptococcal Infections / Q000662:veterinary*; D013291:Streptococcus
chemical_list: D015415:Biomarkers