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Cornejo FA, Muñoz-Villagrán C, Luraschi RA, Sandoval-Díaz MP, Cancino CA, Pugin B, Morales EH, Piotrowski JS, Sandoval JM, Vásquez CC, Arenas FA. Soft-metal(loid)s induce protein aggregation in Escherichia coli. Front Microbiol 2023; 14:1281058. [PMID: 38075883 PMCID: PMC10699150 DOI: 10.3389/fmicb.2023.1281058] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 11/01/2023] [Indexed: 10/08/2024] Open
Abstract
Metal(loid) salts were used to treat infectious diseases in the past due to their exceptional biocidal properties at low concentrations. However, the mechanism of their toxicity has yet to be fully elucidated. The production of reactive oxygen species (ROS) has been linked to the toxicity of soft metal(loid)s such as Ag(I), Au(III), As(III), Cd(II), Hg(II), and Te(IV). Nevertheless, few reports have described the direct, or ROS-independent, effects of some of these soft-metal(loid)s on bacteria, including the dismantling of iron-sulfur clusters [4Fe-4S] and the accumulation of porphyrin IX. Here, we used genome-wide genetic, proteomic, and biochemical approaches under anaerobic conditions to evaluate the direct mechanisms of toxicity of these metal(loid)s in Escherichia coli. We found that certain soft-metal(loid)s promote protein aggregation in a ROS-independent manner. This aggregation occurs during translation in the presence of Ag(I), Au(III), Hg(II), or Te(IV) and post-translationally in cells exposed to Cd(II) or As(III). We determined that aggregated proteins were involved in several essential biological processes that could lead to cell death. For instance, several enzymes involved in amino acid biosynthesis were aggregated after soft-metal(loid) exposure, disrupting intracellular amino acid concentration. We also propose a possible mechanism to explain how soft-metal(loid)s act as proteotoxic agents.
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Affiliation(s)
- Fabián A. Cornejo
- Laboratorio de Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Claudia Muñoz-Villagrán
- Laboratorio de Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Roberto A. Luraschi
- Laboratorio de Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - María P. Sandoval-Díaz
- Laboratorio de Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Camila A. Cancino
- Laboratorio de Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Benoit Pugin
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH, Zürich, Switzerland
| | | | | | | | - Claudio C. Vásquez
- Laboratorio de Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Felipe A. Arenas
- Laboratorio de Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
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2
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Muñoz-Diaz P, Jiménez K, Luraschi R, Cornejo F, Figueroa M, Vera C, Rivas-Pardo A, Sandoval JM, Vásquez C, Arenas F. Anaerobic RSH-dependent tellurite reduction contributes to Escherichia coli tolerance against tellurite. Biol Res 2022; 55:13. [PMID: 35313991 PMCID: PMC8935827 DOI: 10.1186/s40659-022-00383-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 03/07/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Tellurium is a rare metalloid that exerts high toxicity on cells, especially on bacteria, partly due to reactive oxygen species (ROS) generation. Moreover, it has also been observed that tellurite can target free cell thiols groups (RSH) (i.e. reduced glutathione (GSH)), enhancing the cellular redox imbalance. Additionally, in vitro experiments have suggested that several enzymes can reduce tellurite (IV) to its elemental form (0); where RSH present on their active sites may be responsible for the process. Nevertheless, the mechanisms implemented by bacteria for tellurite reduction and its role in resistance have not been evaluated in vivo. RESULTS This work shows that tellurite reduction to elemental tellurium is increased under anaerobic conditions in E. coli cells. The in vivo tellurite reduction is related to the intracellular concentration of total RSH, in the presence and absence of oxygen. This metabolization of tellurite directly contributes to the resistance of the bacteria to the oxyanion. CONCLUSIONS We demonstrated that in vivo tellurite reduction is related to the intracellular thiol concentration, i.e. large availability of cellular RSH groups, results in a more significant reduction of tellurite. Furthermore, we observed that, when the bacterium exhibits less resistance to the oxyanion, a decreased tellurite reduction was seen, affecting the growth fitness. Together, these results let us propose that tellurite reduction and the intracellular RSH content are related to the oxyanion bacterial resistance, this tripartite mechanism in an oxygen-independent anaerobic process.
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Affiliation(s)
- P Muñoz-Diaz
- Laboratorio Microbiología Molecular, Departamento de Biología, Facultad de Química Y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - K Jiménez
- Laboratorio Microbiología Molecular, Departamento de Biología, Facultad de Química Y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - R Luraschi
- Laboratorio Microbiología Molecular, Departamento de Biología, Facultad de Química Y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - F Cornejo
- Laboratorio Microbiología Molecular, Departamento de Biología, Facultad de Química Y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - M Figueroa
- Laboratorio Microbiología Molecular, Departamento de Biología, Facultad de Química Y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - C Vera
- Laboratorio Microbiología Molecular, Departamento de Biología, Facultad de Química Y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - A Rivas-Pardo
- Laboratorio de Genómica Microbiana, Centro de Genómica Y Bioinformática, Universidad Mayor, Santiago, Chile
| | - J M Sandoval
- Facultad de Ciencias, Universidad Arturo Prat, Iquique, Chile
| | - C Vásquez
- Laboratorio Microbiología Molecular, Departamento de Biología, Facultad de Química Y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - F Arenas
- Laboratorio Microbiología Molecular, Departamento de Biología, Facultad de Química Y Biología, Universidad de Santiago de Chile, Santiago, Chile.
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3
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Goff JL, Boyanov MI, Kemner KM, Yee N. The role of cysteine in tellurate reduction and toxicity. Biometals 2021; 34:937-946. [PMID: 34255250 DOI: 10.1007/s10534-021-00319-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 05/13/2021] [Indexed: 11/29/2022]
Abstract
The tellurium oxyanion tellurate is toxic to living organisms even at low concentrations; however, its mechanism of toxicity is poorly understood. Here, we show that exposure of Escherichia coli K-12 to tellurate results in reduction to elemental tellurium (Te[0]) and the formation of intracellular reactive oxygen species (ROS). Toxicity assays performed with E. coli indicated that pre-oxidation of the intracellular thiol pools increases cellular resistance to tellurate-suggesting that intracellular thiols are important in tellurate toxicity. X-ray absorption spectroscopy experiments demonstrated that cysteine reduces tellurate to elemental tellurium. This redox reaction was found to generate superoxide anions. These results indicate that tellurate reduction to Te(0) by cysteine is a source of ROS in the cytoplasm of tellurate-exposed cells.
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Affiliation(s)
- Jennifer L Goff
- Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ, 08854, USA.
| | - Maxim I Boyanov
- Bulgarian Academy of Sciences, Institute of Chemical Engineering, 1113, Sofia, Bulgaria.,Biosciences Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Kenneth M Kemner
- Biosciences Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Nathan Yee
- Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ, 08854, USA.,Department of Environmental Sciences, Rutgers University, New Brunswick, NJ, 08901, USA
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4
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Figueroa M, Fernandez V, Arenas-Salinas M, Ahumada D, Muñoz-Villagrán C, Cornejo F, Vargas E, Latorre M, Morales E, Vásquez C, Arenas F. Synthesis and Antibacterial Activity of Metal(loid) Nanostructures by Environmental Multi-Metal(loid) Resistant Bacteria and Metal(loid)-Reducing Flavoproteins. Front Microbiol 2018; 9:959. [PMID: 29869640 PMCID: PMC5962736 DOI: 10.3389/fmicb.2018.00959] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 04/24/2018] [Indexed: 12/13/2022] Open
Abstract
Microbes are suitable candidates to recover and decontaminate different environments from soluble metal ions, either via reduction or precipitation to generate insoluble, non-toxic derivatives. In general, microorganisms reduce toxic metal ions generating nanostructures (NS), which display great applicability in biotechnological processes. Since the molecular bases of bacterial reduction are still unknown, the search for new -environmentally safe and less expensive- methods to synthesize NS have made biological systems attractive candidates. Here, 47 microorganisms isolated from a number of environmental samples were analyzed for their tolerance or sensitivity to 19 metal(loid)s. Ten of them were highly tolerant to some of them and were assessed for their ability to reduce these toxicants in vitro. All isolates were analyzed by 16S rRNA gene sequencing, fatty acids composition, biochemical tests and electron microscopy. Results showed that they belong to the Enterobacter, Staphylococcus, Acinetobacter, and Exiguobacterium genera. Most strains displayed metal(loid)-reducing activity using either NADH or NADPH as cofactor. While Acinetobacter schindleri showed the highest tellurite ( TeO32- ) and tetrachloro aurate ( AuCl4- ) reducing activity, Staphylococcus sciuri and Exiguobacterium acetylicum exhibited selenite ( SeO32- ) and silver (Ag+) reducing activity, respectively. Based on these results, we used these bacteria to synthetize, in vivo and in vitro Te, Se, Au, and Ag-containing nanostructures. On the other hand, we also used purified E. cloacae glutathione reductase to synthesize in vitro Te-, Ag-, and Se-containing NS, whose morphology, size, composition, and chemical composition were evaluated. Finally, we assessed the putative anti-bacterial activity exhibited by the in vitro synthesized NS: Te-containing NS were more effective than Au-NS in inhibiting Escherichia coli and Listeria monocytogenes growth. Aerobically synthesized TeNS using MF09 crude extracts showed MICs of 45- and 66- μg/ml for E. coli and L. monocytogenes, respectively. Similar MIC values (40 and 82 μg/ml, respectively) were observed for TeNS generated using crude extracts from gorA-overexpressing E. coli. In turn, AuNS MICs for E. coli and L. monocytogenes were 64- and 68- μg/ml, respectively.
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Affiliation(s)
- Maximiliano Figueroa
- Laboratorio Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Valentina Fernandez
- Laboratorio Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | | | - Diego Ahumada
- Laboratorio Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Claudia Muñoz-Villagrán
- Laboratorio Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile.,Departamento de Ciencias Básicas, Facultad de Ciencia, Universidad Santo Tomas, Sede Santiago, Chile
| | - Fabián Cornejo
- Laboratorio Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Esteban Vargas
- Center for the Development of Nanoscience and Nanotechnology, Santiago, Chile
| | - Mauricio Latorre
- Mathomics, Centro de Modelamiento Matemático, Universidad de Chile, Beauchef, Santiago, Chile.,Fondap-Center of Genome Regulation, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.,Laboratorio de Bioinformática y Expresión Génica, INTA, Universidad de Chile, Santiago, Chile.,Instituto de Ciencias de la Ingeniería, Universidad de O'Higgins, Rancagua, Chile
| | | | - Claudio Vásquez
- Laboratorio Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Felipe Arenas
- Laboratorio Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
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5
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Belenky P, Ye JD, Porter CBM, Cohen NR, Lobritz MA, Ferrante T, Jain S, Korry BJ, Schwarz EG, Walker GC, Collins JJ. Bactericidal Antibiotics Induce Toxic Metabolic Perturbations that Lead to Cellular Damage. Cell Rep 2015; 13:968-80. [PMID: 26565910 DOI: 10.1016/j.celrep.2015.09.059] [Citation(s) in RCA: 332] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 09/04/2015] [Accepted: 09/17/2015] [Indexed: 01/16/2023] Open
Abstract
Understanding how antibiotics impact bacterial metabolism may provide insight into their mechanisms of action and could lead to enhanced therapeutic methodologies. Here, we profiled the metabolome of Escherichia coli after treatment with three different classes of bactericidal antibiotics (?-lactams, aminoglycosides, quinolones). These treatments induced a similar set of metabolic changes after 30 min that then diverged into more distinct profiles at later time points. The most striking changes corresponded to elevated concentrations of central carbon metabolites, active breakdown of the nucleotide pool, reduced lipid levels, and evidence of an elevated redox state. We examined potential end-target consequences of these metabolic perturbations and found that antibiotic-treated cells exhibited cytotoxic changes indicative of oxidative stress, including higher levels of protein carbonylation, malondialdehyde adducts, nucleotide oxidation, and double-strand DNA breaks. This work shows that bactericidal antibiotics induce a complex set of metabolic changes that are correlated with the buildup of toxic metabolic by-products.
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Affiliation(s)
- Peter Belenky
- Department of Biomedical Engineering and Center of Synthetic Biology, Boston University, 36 Cummington Mall, Boston, MA 02215, USA; Department of Molecular Microbiology and Immunology, Brown University, 171 Meeting Street, Providence, RI 02912, USA.
| | - Jonathan D Ye
- Department of Biomedical Engineering and Center of Synthetic Biology, Boston University, 36 Cummington Mall, Boston, MA 02215, USA
| | - Caroline B M Porter
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, Boston, MA 02115, USA
| | - Nadia R Cohen
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, Boston, MA 02115, USA
| | - Michael A Lobritz
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, Boston, MA 02115, USA; Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02115, USA
| | - Thomas Ferrante
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, Boston, MA 02115, USA
| | - Saloni Jain
- Department of Biomedical Engineering and Center of Synthetic Biology, Boston University, 36 Cummington Mall, Boston, MA 02215, USA; Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Benjamin J Korry
- Department of Molecular Microbiology and Immunology, Brown University, 171 Meeting Street, Providence, RI 02912, USA
| | - Eric G Schwarz
- Department of Biomedical Engineering and Center of Synthetic Biology, Boston University, 36 Cummington Mall, Boston, MA 02215, USA
| | - Graham C Walker
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - James J Collins
- Institute for Medical Engineering & Science, Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, Boston, MA 02115, USA.
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6
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Kanaly RA, Micheletto R, Matsuda T, Utsuno Y, Ozeki Y, Hamamura N. Application of DNA adductomics to soil bacterium Sphingobium sp. strain KK22. Microbiologyopen 2015; 4:841-56. [PMID: 26305056 PMCID: PMC4618615 DOI: 10.1002/mbo3.283] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 07/16/2015] [Accepted: 07/21/2015] [Indexed: 12/21/2022] Open
Abstract
Toward the development of ecotoxicology methods to investigate microbial markers of impacts of hydrocarbon processing activities, DNA adductomic analyses were conducted on a sphingomonad soil bacterium. From growing cells that were exposed or unexposed to acrolein, a commonly used biocide in hydraulic fracturing processes, DNA was extracted, digested to 2'-deoxynucleosides and analyzed by liquid chromatography-positive ionization electrospray-tandem mass spectrometry in selected reaction monitoring mode transmitting the [M + H](+) > [M + H - 116](+) transition over 100 transitions. Overall data shown as DNA adductome maps revealed numerous putative DNA adducts under both conditions with some occurring specifically for each condition. Adductomic analyses of triplicate samples indicated that elevated levels of some targeted putative adducts occurred in exposed cells. Two exposure-specific adducts were identified in exposed cells as 3-(2'-deoxyribosyl)-5,6,7,8-tetrahydro-6-hydroxy-(and 8-hydroxy-)pyrimido[1,2-a]- purine-(3H)-one (6- and 8-hydroxy-PdG) following synthesis of authentic standards of these compounds and subsequent analyses. A time course experiment showed that 6- and 8-hydroxy-PdG were detected in bacterial DNA within 30 min of acrolein exposure but were not detected in unexposed cells. This work demonstrated the first application of DNA adductomics to examine DNA damage in a bacterium and sets a foundation for future work.
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Affiliation(s)
- Robert A Kanaly
- Department of Life and Environmental System Science, Graduate School of Nanobiosciences, Yokohama City University, Kanagawa, Yokohama, 236-0027, Japan
| | - Ruggero Micheletto
- Department of Nanosystem Science, Graduate School of Nanobiosciences, Yokohama City University, Kanagawa, Yokohama, 236-0027, Japan
| | - Tomonari Matsuda
- Research Center for Environmental Quality Management, Kyoto University, Otsu, Shiga, 520-0811, Japan
| | - Youko Utsuno
- Department of Life and Environmental System Science, Graduate School of Nanobiosciences, Yokohama City University, Kanagawa, Yokohama, 236-0027, Japan
| | - Yasuhiro Ozeki
- Department of Life and Environmental System Science, Graduate School of Nanobiosciences, Yokohama City University, Kanagawa, Yokohama, 236-0027, Japan
| | - Natsuko Hamamura
- Center for Marine Environmental Studies, Ehime University, Matsuyama, 790-8577, Japan.,Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, 812-8581, Japan
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7
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Elías A, Díaz-Vásquez W, Abarca-Lagunas MJ, Chasteen TG, Arenas F, Vásquez CC. The ActP acetate transporter acts prior to the PitA phosphate carrier in tellurite uptake by Escherichia coli. Microbiol Res 2015. [DOI: 10.1016/j.micres.2015.04.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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8
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Quorum Sensing Is Accompanied by Global Metabolic Changes in the Opportunistic Human Pathogen Pseudomonas aeruginosa. J Bacteriol 2015; 197:2072-82. [PMID: 25868647 DOI: 10.1128/jb.02557-14] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 04/07/2015] [Indexed: 02/05/2023] Open
Abstract
UNLABELLED Pseudomonas aeruginosa uses N-acyl-homoserine lactone (AHL)-dependent quorum sensing (QS) systems to control the expression of secreted effectors. These effectors can be crucial to the ecological fitness of the bacterium, playing roles in nutrient acquisition, microbial competition, and virulence. In this study, we investigated the metabolic consequences of AHL-dependent QS by monitoring the metabolic profile(s) of a lasI rhlI double mutant (unable to make QS signaling molecules) and its wild-type progenitor as they progressed through the growth curve. Analysis of culture supernatants by (1)H-nuclear magnetic resonance ((1)H-NMR) spectroscopy revealed that at the point where AHL concentrations peaked in the wild type, the metabolic footprints (i.e., extracellular metabolites) of the wild-type and lasI rhlI mutant diverged. Subsequent gas chromatography-mass spectrometry (GC-MS)-based analysis of the intracellular metabolome revealed QS-dependent perturbations in around one-third of all identified metabolites, including altered concentrations of tricarboxylic acid (TCA) cycle intermediates, amino acids, and fatty acids. Further targeted fatty acid methyl ester (FAME) GC-MS-based profiling of the cellular total fatty acid pools revealed that QS leads to changes associated with decreased membrane fluidity and higher chemical stability. However, not all of the changes we observed were necessarily a direct consequence of QS; liquid chromatography (LC)-MS analyses revealed that polyamine levels were elevated in the lasI rhlI mutant, perhaps a response to the absence of QS-dependent adaptations. Our data suggest that QS leads to a global readjustment in central metabolism and provide new insight into the metabolic changes associated with QS during stationary-phase adaptation. IMPORTANCE Quorum sensing (QS) is a transcriptional regulatory mechanism that allows bacteria to coordinate their gene expression profile with the population cell density. The opportunistic human pathogen Pseudomonas aeruginosa uses QS to control the production of secreted virulence factors. In this study, we show that QS elicits a global "metabolic rewiring" in P. aeruginosa. This metabolic rerouting of fluxes is consistent with a variety of drivers, ranging from altered QS-dependent transcription of "metabolic genes" through to the effect(s) of global "metabolic readjustment" as a consequence of QS-dependent exoproduct synthesis, as well as a general stress response, among others. To our knowledge, this is the first study of its kind to assess the global impact of QS on the metabolome.
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9
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Tellurite-mediated damage to the Escherichia coli NDH-dehydrogenases and terminal oxidases in aerobic conditions. Arch Biochem Biophys 2015; 566:67-75. [DOI: 10.1016/j.abb.2014.10.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/27/2014] [Accepted: 10/19/2014] [Indexed: 11/20/2022]
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10
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Global transcriptomic analysis uncovers a switch to anaerobic metabolism in tellurite-exposed Escherichia coli. Res Microbiol 2014; 165:566-70. [DOI: 10.1016/j.resmic.2014.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Revised: 06/30/2014] [Accepted: 07/03/2014] [Indexed: 11/20/2022]
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11
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Macedo-Márquez A, Vázquez-Acevedo M, Ongay-Larios L, Miranda-Astudillo H, Hernández-Muñoz R, González-Halphen D, Grolli S, Ramoni R. Overexpression of a monomeric form of the bovine odorant-binding protein protects Escherichia coli from chemical-induced oxidative stress. Free Radic Res 2014; 48:814-22. [PMID: 24697800 DOI: 10.3109/10715762.2014.910867] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mammalian odorant-binding proteins (OBPs) are soluble lipocalins produced in the nasal mucosa and in other epithelial tissues of several animal species, where they are supposed to serve as scavengers for small structurally unrelated hydrophobic molecules. These would include odorants and toxic aldehydes like 4-hydroxy-2-nonenal (HNE), which are end products of lipid peroxidation; therefore OBP might physiologically contribute to preserve the integrity of epithelial tissues under oxidative stress conditions by removing toxic compounds from the environment and, eventually, driving them to the appropriate degradative pathways. With the aim of developing a biological model based on a living organism for the investigation of the antioxidant properties of OBP, here we asked whether the overexpression of the protein could confer protection from chemical-induced oxidative stress in Escherichia coli. To this aim, bacteria were made to overexpress either GCC-bOBP, a redesigned monomeric mutant of bovine OBP, or its amino-terminal 6-histidine-tagged version 6H-GCC-bOBP. After inducing overexpression for 4 h, bacterial cells were diluted in fresh culture media, and their growth curves were followed in the presence of hydrogen peroxide (H2O2) and tert-Butyl hydroperoxide (tBuOOH), two reactive oxygen species whose toxicity is mainly due to lipid peroxidation, and menadione, a redox-cycling drug producing the superoxide ion. GCC-bOBP and 6H-GCC-bOBP were found to protect bacterial cells from the insulting agents H2O2 and tBuOOH but not from menadione. The obtained data led us to hypothesize that the presence of overexpressed OBP may contribute to protect bacterial cells against oxidative stress probably by sequestering toxic compounds locally produced during the first replication cycles by lipid peroxidation, before bacteria activate their appropriate enzyme-based antioxidative mechanisms.
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Affiliation(s)
- A Macedo-Márquez
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , México D.F. , Mexico
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