title: The metabolic reprogramming evoked by nitrosative stress triggers the anaerobic utilization of citrate in Pseudomonas fluorescens.
abstract: Nitrosative stress is an ongoing challenge that most organisms have to contend with. When nitric oxide (NO) that may be generated either exogenously or endogenously encounters reactive oxygen species (ROS), it produces a set of toxic moieties referred to as reactive nitrogen species (RNS). As these RNS can severely damage essential biomolecules, numerous organisms have evolved elaborate detoxification strategies to nullify RNS. However, the contribution of cellular metabolism in fending off nitrosative stress is poorly understood. Using a variety of functional proteomic and metabolomic analyses, we have identified how the soil microbe Pseudomonas fluorescens reprogrammed its metabolic networks to survive in an environment enriched by sodium nitroprusside (SNP), a generator of nitrosative stress. To combat the RNS-induced ineffective aconitase (ACN) and tricarboxylic acid (TCA) cycle, the microbe invoked the participation of citrate lyase (CL), phosphoenolpyruvate carboxylase (PEPC) and pyruvate phosphate dikinase (PPDK) to convert citrate, the sole source of carbon into pyruvate and ATP. These enzymes were not evident in the control conditions. This metabolic shift was coupled to the concomitant increase in the activities of such classical RNS detoxifiers as nitrate reductase (NR), nitrite reductase (NIR) and S-nitrosoglutathione reductase (GSNOR). Hence, metabolism may hold the clues to the survival of organisms subjected to nitrosative stress and may provide therapeutic cues against RNS-resistant microbes.
authors.affiliation: Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada.
authors.forename: Christopher
authors.initials: C
authors.lastname: Auger
authors.forename: Joseph
authors.initials: J
authors.lastname: Lemire
authors.forename: Dominic
authors.initials: D
authors.lastname: Cecchini
authors.forename: Adam
authors.initials: A
authors.lastname: Bignucolo
authors.forename: Vasu D
authors.initials: VD
authors.lastname: Appanna
mesh_terms: D000693:Anaerobiosis; D000925:Anticoagulants / Q000494:pharmacology; D015415:Biomarkers / Q000378:metabolism*; D019343:Citric Acid / Q000494:pharmacology*; D002952:Citric Acid Cycle / Q000187:drug effects; D015180:Electrophoresis, Gel, Two-Dimensional; D055432:Metabolomics; D009569:Nitric Oxide / Q000378:metabolism; D010085:Oxidative Phosphorylation / Q000187:drug effects; D040901:Proteomics; D011551:Pseudomonas fluorescens / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D026361:Reactive Nitrogen Species / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000925:Anticoagulants; D015415:Biomarkers; D026361:Reactive Nitrogen Species; D019343:Citric Acid; D009569:Nitric Oxide