title: Qualitative Alterations of Bacterial Metabolome after Exposure to Metal Nanoparticles with Bactericidal Properties: A Comprehensive Workflow Based on (1)H NMR, UHPLC-HRMS, and Metabolic Databases.
abstract: Metal nanoparticles (NPs) have proven to be more toxic than bulk analogues of the same chemical composition due to their unique physical properties. The NPs, lately, have drawn the attention of researchers because of their antibacterial and biocidal properties. In an effort to shed light on the mechanism through which the bacteria elimination is achieved and the metabolic changes they undergo, an untargeted metabolomic fingerprint study was carried out on Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria species. The (1)H NMR spectroscopy, in conjunction with high resolution mass-spectrometry (HRMS) and an unsophisticated data processing workflow were implemented. The combined NMR/HRMS data, supported by an open-access metabolomic database, proved to be efficacious in the process of assigning a putative annotation to a wide range of metabolite signals and is a useful tool to appraise the metabolome alterations, as a consequence of bacterial response to NPs. Interestingly, not all the NPs diminished the intracellular metabolites; bacteria treated with iron NPs produced metabolites not present in the nonexposed bacteria sample, implying the activation of previously inactive metabolic pathways. In contrast, copper and iron-copper NPs reduced the annotated metabolites, alluding to the conclusion that the metabolic pathways (mainly alanine, aspartate, and glutamate metabolism, beta-alanine metabolism, glutathione metabolism, and arginine and proline metabolism) were hindered by the interactions of NPs with the intracellular metabolites.
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina , 45110 Ioannina, Greece.
authors.forename: Theodoros G
authors.initials: TG
authors.lastname: Chatzimitakos
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina , 45110 Ioannina, Greece.
authors.forename: Constantine D
authors.initials: CD
authors.lastname: Stalikas
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects / Q000378:metabolism*; D003300:Copper / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D007501:Iron / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D053858:Metabolic Networks and Pathways / Q000187:drug effects; D055442:Metabolome / Q000187:drug effects*; D053768:Metal Nanoparticles / Q000627:therapeutic use*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000378:metabolism; D057188:Workflow
chemical_list: D000900:Anti-Bacterial Agents; D003300:Copper; D007501:Iron
keywords: NMR; UHPLC-HRMS; bactericides; metabolic databases; metabolomics; metal nanoparticles