title: MALDI-TOF mass spectrometry analysis of proteins and lipids in Escherichia coli exposed to copper ions and nanoparticles.
abstract: Escherichia coli (E. coli) is one of the most important foodborne pathogens to the food industry responsible for diseases as bloody diarrhea, hemorrhagic colitis and life-threatening hemolytic-uremic syndrome. For controlling and eliminating E. coli, metal nano-antimicrobials (NAMs) are frequently used as bioactive systems for applications in food treatments. Most NAMs provide controlled release of metal ions, eventually slowing down or completely inhibiting the growth of undesired microorganisms. Nonetheless, their antimicrobial action is not totally unraveled and is strongly dependent on metal properties and environmental conditions. In this work, we propose the use of matrix-assisted laser desorption ionization time-of-flight (MALDI TOF) mass spectrometry as a powerful tool for direct, time efficient, plausible identification of the cell membrane damage in bacterial strains exposed to copper-based antimicrobial agents, such as soluble salts (chosen as simplified AM material) and copper nanoparticles. E. coli ATCC 25922 strain was selected as 'training bacterium' to set up some critical experimental parameters (i.e. cell concentration, selection of the MALDI matrix, optimal solvent composition, sample preparation method) for the MS analyses. The resulting procedure was then used to attain both protein and lipid fingerprints from E. coli after exposure to different loadings of Cu salts and NPs. Interestingly, bacteria exposed to copper showed over-expression of copper binding proteins and degradation of lipids when treated with soluble salt. These findings were completed with other investigations, such as microbiological experiments. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Campus Universitario, Via E. Orabona 4, Bari, 70126, Italy.|Centro di Ricerca Interdipartimentale S.M.A.R.T., Università degli Studi di Bari Aldo Moro, Campus Universitario, Via E. Orabona 4, Bari, 70126, Italy.
authors.forename: C D
authors.initials: CD
authors.lastname: Calvano
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Campus Universitario, Via E. Orabona 4, Bari, 70126, Italy.
authors.forename: R A
authors.identifier: http://orcid.org/0000-0001-8033-098X
authors.initials: RA
authors.lastname: Picca
authors.affiliation: Dipartimento di Medicina Veterinaria, Università degli Studi di Bari, Strada provinciale per Casamassima Km 3, 70100, Valenzano (BA), Italy.
authors.forename: E
authors.initials: E
authors.lastname: Bonerba
authors.affiliation: Dipartimento di Medicina Veterinaria, Università degli Studi di Bari, Strada provinciale per Casamassima Km 3, 70100, Valenzano (BA), Italy.
authors.forename: G
authors.initials: G
authors.lastname: Tantillo
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Campus Universitario, Via E. Orabona 4, Bari, 70126, Italy.|Centro di Ricerca Interdipartimentale S.M.A.R.T., Università degli Studi di Bari Aldo Moro, Campus Universitario, Via E. Orabona 4, Bari, 70126, Italy.
authors.forename: N
authors.initials: N
authors.lastname: Cioffi
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Campus Universitario, Via E. Orabona 4, Bari, 70126, Italy.|Centro di Ricerca Interdipartimentale S.M.A.R.T., Università degli Studi di Bari Aldo Moro, Campus Universitario, Via E. Orabona 4, Bari, 70126, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Palmisano
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000032:analysis*; D003300:Copper / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D008055:Lipids / Q000032:analysis*; D053758:Nanoparticles / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D008055:Lipids; D003300:Copper
keywords: MALDI; bacteria; copper nanoparticles; lipids; nano-antimicrobials; proteins