title: Pathogen-nematode interaction: Nitrogen supply of Listeria monocytogenes during growth in Caenorhabditis elegans.
abstract: Listeria monocytogenes is a Gram-positive facultatively intracellular human pathogen. Due to its saprophytic lifestyle, L. monocytogenes is assumed to infect and proliferate within soil organisms such as Caenorhabditis elegans. However, little is known about the nutrient usages and metabolite fluxes in this bacterium-nematode interaction. Here, we established a nematode colonization model for L. monocytogenes and a method for the efficient separation of the pathogen from the nematodal gut. Following (15)N labelling of C. elegans and gas chromatography-mass spectrometry-based (15)N isotopologue analysis, we detected a high basal metabolic rate of the nematode, and observed a significant metabolic flux from nitrogenous compounds of the nematode to listerial proteins during proliferation of the pathogen in the worm's intestine. For comparison, we also measured the N fluxes from the gut content into listerial proteins using completely (15)N-labelled Escherichia coli OP50 as food for C. elegans. In both settings, L. monocytogenes prefers the direct incorporation of histidine, arginine and lysine over their de novo biosynthesis. Our data suggest that colonization of nematodes is a strategy of L. monocytogenes to increase its access to N-rich nutrients.
authors.affiliation: Lehrstuhl für Mikrobielle Ökologie, Zentralinstitut für Ernährungs- und Lebensmittelforschung (ZIEL), Technische Universität München, Weihenstephaner Berg 3, 85354, Freising, Germany.
authors.forename: Tanja
authors.initials: T
authors.lastname: Kern
authors.affiliation: Lehrstuhl für Biochemie, Technische Universität München, D-85747, Garching, Germany.
authors.forename: Erika
authors.initials: E
authors.lastname: Kutzner
authors.affiliation: Lehrstuhl für Biochemie, Technische Universität München, D-85747, Garching, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Eisenreich
authors.affiliation: Lehrstuhl für Mikrobielle Ökologie, Zentralinstitut für Ernährungs- und Lebensmittelforschung (ZIEL), Technische Universität München, Weihenstephaner Berg 3, 85354, Freising, Germany.
authors.forename: Thilo M
authors.initials: TM
authors.lastname: Fuchs
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000378:metabolism* / Q000382:microbiology*; D008401:Gas Chromatography-Mass Spectrometry; D054884:Host-Pathogen Interactions; D007553:Isotope Labeling; D008089:Listeria monocytogenes / Q000254:growth & development* / Q000378:metabolism*; D064688:Metabolic Flux Analysis; D009584:Nitrogen / Q000378:metabolism*
chemical_list: D009584:Nitrogen