title: Metabolomic analysis of the food-borne pathogenCampylobacter jejuni: application of direct injection mass spectrometry for mutant characterisation.
abstract: Campylobacter jejuniis the most frequent cause of human food-borne bacterial gastroenteritis but its physiology and biochemistry are poorly understood. Only a few amino-acids can be catabolised and these are known to be important for host colonization. Here we have established methods for rapid high throughput analyses of global metabolism inC. jejuniusing direct injection mass spectrometry (DIMS) to compare metabolite fingerprints of wild-type and mutant strains. Principal component analyses show that the metabolic fingerprint of mutants that have a genomic deletion in genes for key amino-acid catabolic enzymes (eithersdaA,serine dehydratase;aspA,aspartase oraspB,aspartate:glutamate transaminase) can easily be distinguished from the isogenic parental strain. Assignment of putative metabolites showed predictable changes directly associated with the particular metabolic lesion in these mutants as well as more extensive changes in theaspAmutant compared to thesdaAoraspBstrains. Further analyses of acj0150cmutant strain, which has no obvious phenotype, suggested a role for Cj0150 in the conversion of cystathionine to homocysteine. Our results show that DIMS is a useful technique for probing the metabolism of this important pathogen and may help in assigning function to genes encoding novel enzymes with currently unknown metabolic roles.
authors.affiliation: Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN UK.|Department of Biology, University of York, York, North Yorkshire YO10 5DD UK.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Howlett
authors.affiliation: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA UK.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Davey
authors.affiliation: Department of Animal and Plant Sciences, The University of Sheffield, Western Bank, Sheffield, S10 2TN UK.
authors.forename: W
authors.initials: W
authors.lastname: Paul Quick
authors.affiliation: Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Kelly
keywords: Campylobacter jejuni; DIMS; Metabolism; aspA; aspB; sdaA