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Petrova O, Semenova E, Parfirova O, Tsers I, Gogoleva N, Gogolev Y, Nikolaichik Y, Gorshkov V. RpoS-Regulated Genes and Phenotypes in the Phytopathogenic Bacterium Pectobacterium atrosepticum. Int J Mol Sci 2023; 24:17348. [PMID: 38139177 PMCID: PMC10743746 DOI: 10.3390/ijms242417348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/04/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023] Open
Abstract
The alternative sigma factor RpoS is considered to be one of the major regulators providing stress resistance and cross-protection in bacteria. In phytopathogenic bacteria, the effects of RpoS have not been analyzed with regard to cross-protection, and genes whose expression is directly or indirectly controlled by RpoS have not been determined at the whole-transcriptome level. Our study aimed to determine RpoS-regulated genes and phenotypes in the phytopathogenic bacterium Pectobacterium atrosepticum. Knockout of the rpoS gene in P. atrosepticum affected the long-term starvation response, cross-protection, and virulence toward plants with enhanced immune status. The whole-transcriptome profiles of the wild-type P. atrosepticum strain and its ΔrpoS mutant were compared under different experimental conditions, and functional gene groups whose expression was affected by RpoS were determined. The RpoS promoter motif was inferred within the promoter regions of the genes affected by rpoS deletion, and the P. atrosepticum RpoS regulon was predicted. Based on RpoS-controlled phenotypes, transcriptome profiles, and RpoS regulon composition, the regulatory role of RpoS in P. atrosepticum is discussed.
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Affiliation(s)
- Olga Petrova
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, 420111 Kazan, Russia; (O.P.); (E.S.); (O.P.); (I.T.); (N.G.); (Y.G.)
| | - Elizaveta Semenova
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, 420111 Kazan, Russia; (O.P.); (E.S.); (O.P.); (I.T.); (N.G.); (Y.G.)
| | - Olga Parfirova
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, 420111 Kazan, Russia; (O.P.); (E.S.); (O.P.); (I.T.); (N.G.); (Y.G.)
| | - Ivan Tsers
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, 420111 Kazan, Russia; (O.P.); (E.S.); (O.P.); (I.T.); (N.G.); (Y.G.)
| | - Natalia Gogoleva
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, 420111 Kazan, Russia; (O.P.); (E.S.); (O.P.); (I.T.); (N.G.); (Y.G.)
| | - Yuri Gogolev
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, 420111 Kazan, Russia; (O.P.); (E.S.); (O.P.); (I.T.); (N.G.); (Y.G.)
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia
| | - Yevgeny Nikolaichik
- Department of Molecular Biology, Belarusian State University, 220030 Minsk, Belarus;
| | - Vladimir Gorshkov
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, 420111 Kazan, Russia; (O.P.); (E.S.); (O.P.); (I.T.); (N.G.); (Y.G.)
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia
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2
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Williams SM, Chatterji D. Dps Functions as a Key Player in Bacterial Iron Homeostasis. ACS OMEGA 2023; 8:34299-34309. [PMID: 37779979 PMCID: PMC10536872 DOI: 10.1021/acsomega.3c03277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 08/24/2023] [Indexed: 10/03/2023]
Abstract
Iron plays a vital role in the maintenance of life, being central to various cellular processes, from respiration to gene regulation. It is essential for iron to be stored in a nontoxic and readily available form. DNA binding proteins under starvation (Dps) belong to the ferritin family of iron storage proteins and are adept at storing iron in their hollow protein shells. Existing solely in prokaryotes, these proteins have the additional functions of DNA binding and protection from oxidative stress. Iron storage proteins play a functional role in storage, release, and transfer of iron and therefore are central to the optimal functioning of iron homeostasis. Here we review the multifarious properties of Dps through relevant biochemical and structural studies with a focus on iron storage and ferroxidation. We also examine the role of Dps as a possible candidate as an iron donor to iron-sulfur (Fe-S) clusters, which are ubiquitous to many biological processes.
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Affiliation(s)
- Sunanda Margrett Williams
- Institute
of Structural and Molecular Biology, Birkbeck,
University of London, Malet Street, London WC1E
7HX, United Kingdom
| | - Dipankar Chatterji
- Molecular
Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
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3
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Furukawa Y, Shintani A, Narikiyo S, Sue K, Akutsu M, Muraki N. Characterization of a novel cysteine-less Cu/Zn-superoxide dismutase in Paenibacillus lautus missing a conserved disulfide bond. J Biol Chem 2023; 299:105040. [PMID: 37442237 PMCID: PMC10432803 DOI: 10.1016/j.jbc.2023.105040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 07/01/2023] [Accepted: 07/06/2023] [Indexed: 07/15/2023] Open
Abstract
Cu/Zn-superoxide dismutase (CuZnSOD) is an enzyme that binds a copper and zinc ion and also forms an intramolecular disulfide bond. Together with the copper ion as the active site, the disulfide bond is completely conserved among these proteins; indeed, the disulfide bond plays critical roles in maintaining the catalytically competent conformation of CuZnSOD. Here, we found that a CuZnSOD protein in Paenibacillus lautus (PaSOD) has no Cys residue but exhibits a significant level of enzyme activity. The crystal structure of PaSOD revealed hydrophobic and hydrogen-bonding interactions in substitution for the disulfide bond of the other CuZnSOD proteins. Also notably, we determined that PaSOD forms a homodimer through an additional domain with a novel fold at the N terminus. While the advantages of lacking Cys residues and adopting a novel dimer configuration remain obscure, PaSOD does not require a disulfide-introducing/correcting system for maturation and could also avoid misfolding caused by aberrant thiol oxidations under an oxidative environment.
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Affiliation(s)
| | | | | | - Kaori Sue
- Department of Chemistry, Keio University, Yokohama, Japan
| | - Masato Akutsu
- Department of Chemistry, Keio University, Yokohama, Japan
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4
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Hormazábal DB, Reyes ÁB, Castro F, Cabrera AR, Dreyse P, Melo-González F, Bueno SM, González IA, Palavecino CE. Synergistic effect of Ru(II)-based type II photodynamic therapy with cefotaxime on clinical isolates of ESBL-producing Klebsiella pneumoniae. Biomed Pharmacother 2023; 164:114949. [PMID: 37267640 DOI: 10.1016/j.biopha.2023.114949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/12/2023] [Accepted: 05/27/2023] [Indexed: 06/04/2023] Open
Abstract
Multidrug-resistant bacteria, such as ESBL producing-Klebsiella pneumoniae, have increased substantially, encouraging the development of complementary therapies such as photodynamic inactivation (PDI). PDI uses photosensitizer (PS) compounds that kill bacteria using light to produce reactive oxygen species. We test Ru-based PS to inhibit K. pneumoniae and advance in the characterization of the mode of action. The PDI activity of PSRu-L2, and PSRu-L3, was determined by serial micro dilutions exposing K. pneumoniae to 0.612 J/cm 2 of light dose. PS interaction with cefotaxime was determined on a collection of 118 clinical isolates of K. pneumoniae. To characterize the mode of action of PDI, the bacterial response to oxidative stress was measured by RT-qPCR. Also, the cytotoxicity on mammalian cells was assessed by trypan blue exclusion. Over clinical isolates, the compounds are bactericidal, at doses of 8 µg/mL PSRu-L2 and 4 µg/mL PSRu-L3, inhibit bacterial growth by 3 log10 (>99.9%) with a lethality of 30 min. A remarkable synergistic effect of the PSRu-L2 and PSRu-L3 compounds with cefotaxime increased the bactericidal effect in a subpopulation of 66 ESBL-clinical isolates to > 6 log10 with an FIC-value of 0.16 and 0.17, respectively. The bacterial transcription response suggests that the mode of action occurs through Type II oxidative stress. The upregulation of the extracytoplasmic virulence factors mrkD, magA, and rmpA accompanied this response. Also, the compounds show little or no toxicity in vitro on HEp-2 and HEK293T cells. Through the type II effect, PSs compounds are bactericidal, synergistic on K. pneumoniae, and have low cytotoxicity in mammals.
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Affiliation(s)
- Dafne Berenice Hormazábal
- Laboratorio de Microbiología Celular, Instituto de Investigación y Postgrado, Facultad de Ciencias de la Salud, Universidad Central de Chile, Lord Cochrane 418, Santiago 8330546, Chile
| | - Ángeles Beatriz Reyes
- Laboratorio de Microbiología Celular, Instituto de Investigación y Postgrado, Facultad de Ciencias de la Salud, Universidad Central de Chile, Lord Cochrane 418, Santiago 8330546, Chile
| | - Francisco Castro
- Departamento de Química Inorgánica, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Macul, Santiago, Chile
| | - Alan R Cabrera
- Departamento de Química Inorgánica, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Macul, Santiago, Chile
| | - Paulina Dreyse
- Departamento de Química, Universidad Técnica Federico Santa María, Av. España 1680, Casilla 2390123, Valparaíso, Chile
| | - Felipe Melo-González
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8330025, Chile
| | - Susan M Bueno
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8330025, Chile
| | - Iván A González
- Departamento de Química, Facultad de Ciencias Naturales, Matemática y del Medio Ambiente, Universidad Tecnológica Metropolitana, Las Palmeras 3360, Ñuñoa, Santiago 7800003, Chile.
| | - Christian Erick Palavecino
- Laboratorio de Microbiología Celular, Instituto de Investigación y Postgrado, Facultad de Ciencias de la Salud, Universidad Central de Chile, Lord Cochrane 418, Santiago 8330546, Chile.
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5
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Sharma R, Mishanina TV. A riboswitch-controlled manganese exporter (Alx) tunes intracellular Mn 2+ concentration in E. coli at alkaline pH. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.07.539761. [PMID: 37214827 PMCID: PMC10197570 DOI: 10.1101/2023.05.07.539761] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Cells use transition metal ions as structural components of biomolecules and cofactors in enzymatic reactions, making transition metals vital cellular components. The buildup of a particular metal ion in certain stress conditions becomes harmful to the organism due to the misincorporation of the excess ion into biomolecules, resulting in perturbed enzymatic activity or metal-catalyzed formation of reactive oxygen species. Organisms optimize metal concentration by regulating the expression of proteins that import and export that metal, often in a metal concentration-dependent manner. One such regulation mechanism is via riboswitches, which are 5'-untranslated regions (UTR) of an mRNA that undergo conformational changes to promote or inhibit the expression of the downstream gene, commonly in response to a ligand. The yybP-ykoY family of bacterial riboswitches shares a conserved aptamer domain that binds manganese (Mn2+). In E. coli, the yybP-ykoY riboswitch precedes and regulates the expression of two genes: mntP, which based on extensive genetic evidence encodes an Mn2+ exporter, and alx, which encodes a putative metal ion transporter whose cognate ligand is currently in question. Expression of alx is upregulated by both elevated intracellular concentrations of Mn2+ and alkaline pH. With metal ion measurements and gene expression studies, we demonstrate that the alkalinization of media increases cytoplasmic Mn2+ content, which in turn enhances alx expression. Alx then exports excess Mn2+ to prevent toxic buildup of the metal inside the cell, with the export activity maximal at alkaline pH. Using mutational and complementation experiments, we pinpoint a set of acidic residues in the predicted transmembrane segments of Alx that play a crucial role in its Mn2+ export. We propose that Alx-mediated Mn2+ export provides a primary protective layer that fine-tunes the cytoplasmic Mn2+ levels, especially during alkaline stress.
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Affiliation(s)
- Ravish Sharma
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093
| | - Tatiana V. Mishanina
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093
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6
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Sharma KK, Singh D, Mohite SV, Williamson PR, Kennedy JF. Metal manipulators and regulators in human pathogens: A comprehensive review on microbial redox copper metalloenzymes "multicopper oxidases and superoxide dismutases". Int J Biol Macromol 2023; 233:123534. [PMID: 36740121 DOI: 10.1016/j.ijbiomac.2023.123534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/17/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023]
Abstract
The chemistry of metal ions with human pathogens is essential for their survival, energy generation, redox signaling, and niche dominance. To regulate and manipulate the metal ions, various enzymes and metal chelators are present in pathogenic bacteria. Metalloenzymes incorporate transition metal such as iron, zinc, cobalt, and copper in their reaction centers to perform essential metabolic functions; however, iron and copper have gained more importance. Multicopper oxidases have the ability to perform redox reaction on phenolic substrates with the help of copper ions. They have been reported from Enterobacteriaceae, namely Salmonella enterica, Escherichia coli, and Yersinia enterocolitica, but their role in virulence is still poorly understood. Similarly, superoxide dismutases participate in reducing oxidative stress and allow the survival of pathogens. Their role in virulence and survival is well established in Salmonella typhimurium and Mycobacterium tuberculosis. Further, to ensure survival against stress, like metal starvation or metal toxicity, redox metalloenzymes and metal transportation systems of pathogens actively participate in metal homeostasis. Recently, the omics and protein structure biology studies have helped to predict new targets for regulation the colonization potential of the pathogenic strains. The current review is focused on the major roles of redox metalloenzymes, especially MCOs and SODs of human pathogenic bacteria.
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Affiliation(s)
- Krishna Kant Sharma
- Laboratory of Enzymology and Gut Microbiology, Department of Microbiology, Maharshi Dayanand University, Rohtak 124001, Haryana, India.
| | - Deepti Singh
- Laboratory of Enzymology and Gut Microbiology, Department of Microbiology, Maharshi Dayanand University, Rohtak 124001, Haryana, India
| | - Shreya Vishwas Mohite
- Laboratory of Enzymology and Gut Microbiology, Department of Microbiology, Maharshi Dayanand University, Rohtak 124001, Haryana, India
| | - Peter R Williamson
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - John F Kennedy
- Chembiotech Laboratories, Advanced Science and Technology Institute, 5 the Croft, Buntsford Drive, Stoke Heath, Bromsgrove, Worcs B60 4JE, UK
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7
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Ares Á, Sakai S, Sasaki T, Shimamura S, Mitarai S, Nunoura T. Sequestration and efflux largely account for cadmium and copper resistance in the deep-sea Nitratiruptor sp. SB155-2 (phylum Campylobacterota). Environ Microbiol 2022; 24:6144-6163. [PMID: 36284406 PMCID: PMC10092412 DOI: 10.1111/1462-2920.16255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 10/20/2022] [Indexed: 01/12/2023]
Abstract
In deep-sea hydrothermal vent environments, metal-enriched fluids and sediments abound, making these habitats ideal to study metal resistance in prokaryotes. In this investigation, we employed transcriptomics and shotgun proteomics with scanning transmission electron microscopy and energy-dispersive x-ray spectroscopy (STEM-EDX) to better understand mechanisms of tolerance for cadmium (Cd) and copper (Cu) at stress-inducing concentrations in Nitratiruptor sp. SB155-2 (phylum Campylobacterota). Transcriptomic profiles were remarkably different in the presence of these two metals, displaying 385 (19%) and 629 (31%) differentially transcribed genes (DTG) in the presence of Cd(II) and Cu(II), respectively, while only 7% of differentially transcribed (DT) genes were shared, with genes for non-specific metal transporters and genes involved in oxidative stress-response predominating. Transcriptomic and proteomic analyses confirmed that metal-specific DT pathways under Cu(II) stress, including those involving sulfur, cysteine, and methionine, are likely required for high-affinity efflux systems, while flagella formation and chemotaxis were over-represented under Cd(II) stress. Consistent with these differences, STEM-EDX analysis revealed that polyphosphate-like granules (pPLG), the formation of CdS particles, and the periplasmic space are crucial for Cd(II) sequestration. Overall, this study provides new insights regarding metal-specific adaptations of Campylobacterota to deep-sea hydrothermal vent environments.
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Affiliation(s)
- Ángela Ares
- Marine Biophysics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
| | - Sanae Sakai
- Super-Cutting-Edge Grand and Advanced Research (SUGAR) Program, Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-STAR), Japan Agency for Marine-Earth Science & Technology (JAMSTEC), Yokosuka, Japan
| | - Toshio Sasaki
- Imaging section, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
| | - Shigeru Shimamura
- Super-Cutting-Edge Grand and Advanced Research (SUGAR) Program, Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-STAR), Japan Agency for Marine-Earth Science & Technology (JAMSTEC), Yokosuka, Japan
| | - Satoshi Mitarai
- Marine Biophysics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
| | - Takuro Nunoura
- Research and Development Center for Marine Biosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
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8
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Uppalapati SR, Vazquez-Torres A. Manganese Utilization in Salmonella Pathogenesis: Beyond the Canonical Antioxidant Response. Front Cell Dev Biol 2022; 10:924925. [PMID: 35903545 PMCID: PMC9315381 DOI: 10.3389/fcell.2022.924925] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 06/22/2022] [Indexed: 11/16/2022] Open
Abstract
The metal ion manganese (Mn2+) is equally coveted by hosts and bacterial pathogens. The host restricts Mn2+ in the gastrointestinal tract and Salmonella-containing vacuoles, as part of a process generally known as nutritional immunity. Salmonella enterica serovar Typhimurium counteract Mn2+ limitation using a plethora of metal importers, whose expression is under elaborate transcriptional and posttranscriptional control. Mn2+ serves as cofactor for a variety of enzymes involved in antioxidant defense or central metabolism. Because of its thermodynamic stability and low reactivity, bacterial pathogens may favor Mn2+-cofactored metalloenzymes during periods of oxidative stress. This divalent metal catalyzes metabolic flow through lower glycolysis, reductive tricarboxylic acid and the pentose phosphate pathway, thereby providing energetic, redox and biosynthetic outputs associated with the resistance of Salmonella to reactive oxygen species generated in the respiratory burst of professional phagocytic cells. Combined, the oxyradical-detoxifying properties of Mn2+ together with the ability of this divalent metal cation to support central metabolism help Salmonella colonize the mammalian gut and establish systemic infections.
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Affiliation(s)
- Siva R. Uppalapati
- Department of Immunology & Microbiology, University of Colorado School of Medicine, Aurora, CO, United States,*Correspondence: Siva R. Uppalapati, ; Andres Vazquez-Torres,
| | - Andres Vazquez-Torres
- Department of Immunology & Microbiology, University of Colorado School of Medicine, Aurora, CO, United States,Veterans Affairs Eastern Colorado Health Care System, Denver, CO, United States,*Correspondence: Siva R. Uppalapati, ; Andres Vazquez-Torres,
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9
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Novoa-Aponte L, Argüello JM. Unique underlying principles shaping copper homeostasis networks. J Biol Inorg Chem 2022; 27:509-528. [PMID: 35802193 PMCID: PMC9470648 DOI: 10.1007/s00775-022-01947-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/27/2022] [Indexed: 12/27/2022]
Abstract
Abstract Copper is essential in cells as a cofactor for key redox enzymes. Bacteria have acquired molecular components that sense, uptake, distribute, and expel copper ensuring that cuproenzymes are metallated and steady-state metal levels are maintained. Toward preventing deleterious reactions, proteins bind copper ions with high affinities and transfer the metal via ligand exchange, warranting that copper ions are always complexed. Consequently, the directional copper distribution within cell compartments and across cell membranes requires specific dynamic interactions and metal exchange between cognate holo-apo protein partners. These metal exchange reactions are determined by thermodynamic and kinetics parameters and influenced by mass action. Then, copper distribution can be conceptualized as a molecular system of singular interacting elements that maintain a physiological copper homeostasis. This review focuses on the impact of copper high-affinity binding and exchange reactions on the homeostatic mechanisms, the conceptual models to describe the cell as a homeostatic system, the various molecule functions that contribute to copper homeostasis, and the alternative system architectures responsible for copper homeostasis in model bacteria. Graphical Abstract ![]()
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Affiliation(s)
- Lorena Novoa-Aponte
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 60 Prescott St, Worcester, MA, 01605, USA.,Genetics and Metabolism Section, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, 20892, USA
| | - José M Argüello
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 60 Prescott St, Worcester, MA, 01605, USA.
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10
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Zhang S, Ma X, Yu H, Lu X, Liu J, Zhang L, Wang G, Ye J, Ning G. Silver(I) metal-organic framework-embedded polylactic acid electrospun fibrous membranes for efficient inhibition of bacteria. Dalton Trans 2022; 51:6673-6681. [PMID: 35411886 DOI: 10.1039/d1dt04234c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
With recent outbreaks of fatal strains of diseases and the emergency of antibiotic resistance, there is a pressing demand to discover bactericidal materials that can effectively reduce or prevent infections by pathogenic bacteria. Herein, silver(I) metal organic frameworks Ag2(HBTC) were embedded into biocompatible polylactic acid (PLA) fibrous membranes through an electrospinning process as an antibiotic-free material for effective bacterial killing. The as-synthesized Ag2(HBTC)/PLA composite membrane showed an inactivation efficiency of more than 99.9% against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) at a concentration of 200-250 mg L-1. Mechanistic investigation indicated that the steady release of Ag+ ions and ˙OH generation from the composites contributed to the efficient antibacterial activities through irreversible damage to the bacterial cell membranes. In-depth proteomic analysis demonstrated that Ag2(HBTC)/PLA exerted a biological effect towards bacterial cells through down-regulating functional proteins, thereby destroying the central biochemical pathways of the cellular energy metabolism process, reducing resistance to oxidative damage and inhibiting cell division. In general, this study shows a promising perspective on designing MOF/PLA membranes with broad-spectrum disinfection capability for potential environmental sterilization and public healthcare protection.
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Affiliation(s)
- Siqi Zhang
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian, Liaoning, 116024, PR China
| | - Xiao Ma
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian, Liaoning, 116024, PR China
| | - Hailong Yu
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian, Liaoning, 116024, PR China
| | - Xinyi Lu
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian, Liaoning, 116024, PR China.,CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, PR China.
| | - Jianhui Liu
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, PR China.
| | - Lihua Zhang
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, PR China.
| | - Guangyao Wang
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian, Liaoning, 116024, PR China
| | - Junwei Ye
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian, Liaoning, 116024, PR China
| | - Guiling Ning
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian, Liaoning, 116024, PR China
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11
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Vazulka S, Schiavinato M, Wagenknecht M, Cserjan-Puschmann M, Striedner G. Interaction of Periplasmic Fab Production and Intracellular Redox Balance in Escherichia coli Affects Product Yield. ACS Synth Biol 2022; 11:820-834. [PMID: 35041397 PMCID: PMC8859853 DOI: 10.1021/acssynbio.1c00502] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Antibody fragments such as Fab's require the formation of disulfide bonds to achieve a proper folding state. During their recombinant, periplasmic expression in Escherichia coli, oxidative folding is mediated by the DsbA/DsbB system in concert with ubiquinone. Thereby, overexpression of Fab's is linked to the respiratory chain, which is not only immensely important for the cell's energy household but also known as a major source of reactive oxygen species. However, the effects of an increased oxidative folding demand and the consequently required electron flux via ubiquinone on the host cell have not been characterized so far. Here, we show that Fab expression in E. coli BL21(DE3) interfered with the intracellular redox balance, thereby negatively impacting host cell performance. Production of four different model Fab's in lab-scale fed-batch cultivations led to increased oxygen consumption rates and strong cell lysis. An RNA sequencing analysis revealed transcription activation of the oxidative stress-responsive soxS gene in the Fab-producing strains. We attributed this to the accumulation of intracellular superoxide, which was measured using flow cytometry. An exogenously supplemented ubiquinone analogue improved Fab yields up to 82%, indicating that partitioning of the quinone pool between aerobic respiration and oxidative folding limited ubiquinone availability and hence disulfide bond formation capacity. Combined, our results provide a more in-depth understanding of the profound effects that periplasmic Fab expression and in particular disulfide bond formation has on the host cell. Thereby, we show new possibilities to elaborate cell engineering and process strategies for improved host cell fitness and process outcome.
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Affiliation(s)
- Sophie Vazulka
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. Coli, Department of Biotechnology, Institute of Bioprocess Science and Engineering, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria
| | - Matteo Schiavinato
- Department of Biotechnology, Institute of Computational Biology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria
| | - Martin Wagenknecht
- Boehringer Ingelheim RCV GmbH & Co KG, Dr.-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Monika Cserjan-Puschmann
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. Coli, Department of Biotechnology, Institute of Bioprocess Science and Engineering, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria
| | - Gerald Striedner
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. Coli, Department of Biotechnology, Institute of Bioprocess Science and Engineering, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria
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12
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Sharma VK, Akavaram S, Bayles DO. Genomewide transcriptional response of Escherichia coli O157:H7 to norepinephrine. BMC Genomics 2022; 23:107. [PMID: 35135480 PMCID: PMC8822769 DOI: 10.1186/s12864-021-08167-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/10/2021] [Indexed: 01/18/2023] Open
Abstract
Background Chemical signaling between a mammalian host and intestinal microbes is health and maintenance of ‘healthy’ intestinal microbiota. Escherichia coli O157:H7 can hijack host- and microbiota-produced chemical signals for survival in a harsh and nutritionally competitive gastrointestinal environment and for intestinal colonization. Norepinephrine (NE) produced by sympathetic neurons of the enteric nervous system has been shown in vitro to induce expression of genes controlling E. coli O157:H7 swimming motility, acid resistance, and adherence to epithelial cells. A previous study used a microarray approach to identify differentially expressed genes in E. coli O157:H7 strain EDL933 in response to NE. To elucidate a comprehensive transcriptional response to NE, we performed RNA-Seq on rRNA-depleted RNA of E. coli O157:H7 strain NADC 6564, an isolate of a foodborne E. coli O157:H7 strain 86–24. The reads generated by RNA-Seq were mapped to NADC 6564 genome using HiSat2. The mapped reads were quantified by htseq-count against the genome of strain NADC 6564. The differentially expressed genes were identified by analyzing quantified reads by DESeq2. Results Of the 585 differentially expressed genes (≥ 2.0-fold; p < 0.05), many encoded pathways promoting ability of E. coli O157:H7 strain NADC 6564 to colonize intestines of carrier animals and to produce disease in an incidental human host through increased adherence to epithelial cells and production of Shiga toxins. In addition, NE exposure also induced the expression of genes encoding pathways conferring prolonged survival at extreme acidity, controlling influx/efflux of specific nutrients/metabolites, and modulating tolerance to various stressors. A correlation was also observed between the EvgS/EvgA signal transduction system and the ability of bacterial cells to survive exposure to high acidity for several hours. Many genes involved in nitrogen, sulfur, and amino acid uptake were upregulated while genes linked to iron (Fe3+) acquisition and transport were downregulated. Conclusion The availability of physiological levels of NE in gastrointestinal tract could serve as an important cue for E. coli O157:H7 to engineer its virulence, stress, and metabolic pathways for colonization in reservoir animals, such as cattle, causing illness in humans, and surviving outside of a host. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-08167-z.
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Affiliation(s)
- Vijay K Sharma
- Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, ARS-USDA, Ames, IA, 50010, USA.
| | - Suryatej Akavaram
- Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, ARS-USDA, Ames, IA, 50010, USA.,Current address: 4302 TX-332, Freeport, TX, 77541, USA
| | - Darrell O Bayles
- Infectious Bacterial Diseases Research Unit, National Animal Disease Center, ARS-USDA, Ames, IA, 50010, USA
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13
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Furukawa Y, Shintani A, Kokubo T. A dual role of cysteine residues in the maturation of prokaryotic Cu/Zn-superoxide dismutase. Metallomics 2021; 13:6353531. [PMID: 34402915 DOI: 10.1093/mtomcs/mfab050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/05/2021] [Indexed: 11/14/2022]
Abstract
Bacterial Cu/Zn-superoxide dismutase (SodC) is an enzyme catalyzing the disproportionation of superoxide radicals, to which the binding of copper and zinc ions and the formation of an intramolecular disulfide bond are essential. We previously showed that Escherichia coli SodC (SodC) was prone to spontaneous degradation in vivo in an immature form prior to the introduction of the disulfide bond. The post-translational maintenance involving the metal binding and the disulfide formation would thus control the stability as well as the enzymatic function of SodC; however, a mechanism of the SodC maturation remains obscure. Here, we show that the disulfide-reduced SodC can secure a copper ion as well as a zinc ion through the thiolate groups. Furthermore, the disulfide-reduced SodC was found to bind cuprous and cupric ions more tightly than SodC with the disulfide bond. The thiolate groups ligating the copper ion were then autooxidized to form the intramolecular disulfide bond, leading to the production of enzymatically active SodC. Based upon the experiments in vitro, therefore, we propose a mechanism for the activation of SodC, in which the conserved Cys residues play a dual role: the acquisition of a copper ion for the enzymatic activity and the formation of the disulfide bond for the structural stabilization.
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Affiliation(s)
- Yoshiaki Furukawa
- Laboratory for Mechanistic Chemistry of Biomolecules, Department of Chemistry, Keio University, Yokohama 223-8522, Japan
| | - Atsuko Shintani
- Laboratory for Mechanistic Chemistry of Biomolecules, Department of Chemistry, Keio University, Yokohama 223-8522, Japan
| | - Teppei Kokubo
- Laboratory for Mechanistic Chemistry of Biomolecules, Department of Chemistry, Keio University, Yokohama 223-8522, Japan
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14
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Doukyu N, Taguchi K. Involvement of catalase and superoxide dismutase in hydrophobic organic solvent tolerance of Escherichia coli. AMB Express 2021; 11:97. [PMID: 34189628 PMCID: PMC8241964 DOI: 10.1186/s13568-021-01258-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 06/16/2021] [Indexed: 12/22/2022] Open
Abstract
Escherichia coli strains are generally sensitive to hydrophobic organic solvents such as n-hexane and cyclohexane. Oxidative stress in E. coli by exposure to these hydrophobic organic solvents has been poorly understood. In the present study, we examined organic solvent tolerance and oxygen radical generation in E. coli mutants deficient in reactive oxygen species (ROS)-scavenging enzymes. The organic solvent tolerances in single gene mutants lacking genes encoding superoxide dismutase (sodA, sodB, and sodC), catalase (katE and katG), and alkyl hydroperoxide reductase (ahpCF) were similar to that of parent strain BW25113. We constructed a BW25113-based katE katG double mutant (BW25113∆katE∆katG) and sodA sodB double mutant (BW25113sodA∆sodB). These double-gene mutants were more sensitive to hydrophobic organic solvents than BW25113. In addition, the intracellular ROS levels in E. coli strains increased by the addition of n-hexane or cyclohexane. The ROS levels in BW25113∆katE∆katG and BW25113∆sodA∆sodB induced by exposure to the solvents were higher than that in BW25113. These results suggested that ROS-scavenging enzymes contribute to the maintenance of organic solvent tolerance in E. coli. In addition, the promoter activities of sodA and sodB were significantly increased by exposure to n-hexane.
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Affiliation(s)
- Noriyuki Doukyu
- Department of Life Science, Toyo University, 1-1-1 Izumino, Itakura-machi, Gunma 374-0193 Japan
- Bio-Nano Electronic Research Center, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585 Japan
| | - Katsuya Taguchi
- Department of Life Science, Toyo University, 1-1-1 Izumino, Itakura-machi, Gunma 374-0193 Japan
- Bio-Nano Electronic Research Center, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585 Japan
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15
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Rapacka-Zdończyk A, Woźniak A, Michalska K, Pierański M, Ogonowska P, Grinholc M, Nakonieczna J. Factors Determining the Susceptibility of Bacteria to Antibacterial Photodynamic Inactivation. Front Med (Lausanne) 2021; 8:642609. [PMID: 34055830 PMCID: PMC8149737 DOI: 10.3389/fmed.2021.642609] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 04/12/2021] [Indexed: 01/23/2023] Open
Abstract
Photodynamic inactivation of microorganisms (aPDI) is an excellent method to destroy antibiotic-resistant microbial isolates. The use of an exogenous photosensitizer or irradiation of microbial cells already equipped with endogenous photosensitizers makes aPDI a convenient tool for treating the infections whenever technical light delivery is possible. Currently, aPDI research carried out on a vast repertoire of depending on the photosensitizer used, the target microorganism, and the light delivery system shows efficacy mostly on in vitro models. The search for mechanisms underlying different responses to photodynamic inactivation of microorganisms is an essential issue in aPDI because one niche (e.g., infection site in a human body) may have bacterial subpopulations that will exhibit different susceptibility. Rapidly growing bacteria are probably more susceptible to aPDI than persister cells. Some subpopulations can produce more antioxidant enzymes or have better performance due to efficient efflux pumps. The ultimate goal was and still is to identify and characterize molecular features that drive the efficacy of antimicrobial photodynamic inactivation. To this end, we examined several genetic and biochemical characteristics, including the presence of individual genetic elements, protein activity, cell membrane content and its physical properties, the localization of the photosensitizer, with the result that some of them are important and others do not appear to play a crucial role in the process of aPDI. In the review, we would like to provide an overview of the factors studied so far in our group and others that contributed to the aPDI process at the cellular level. We want to challenge the question, is there a general pattern of molecular characterization of aPDI effectiveness? Or is it more likely that a photosensitizer-specific pattern of molecular characteristics of aPDI efficacy will occur?
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Affiliation(s)
| | - Agata Woźniak
- Laboratory of Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Klaudia Michalska
- Laboratory of Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Michał Pierański
- Laboratory of Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Patrycja Ogonowska
- Laboratory of Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Mariusz Grinholc
- Laboratory of Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Joanna Nakonieczna
- Laboratory of Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
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16
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Shin J, Choe D, Ransegnola B, Hong H, Onyekwere I, Cross T, Shi Q, Cho B, Westblade LF, Brito IL, Dörr T. A multifaceted cellular damage repair and prevention pathway promotes high-level tolerance to β-lactam antibiotics. EMBO Rep 2021; 22:e51790. [PMID: 33463026 PMCID: PMC7857431 DOI: 10.15252/embr.202051790] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/17/2020] [Accepted: 12/02/2020] [Indexed: 12/27/2022] Open
Abstract
Bactericidal antibiotics are powerful agents due to their ability to convert essential bacterial functions into lethal processes. However, many important bacterial pathogens are remarkably tolerant against bactericidal antibiotics due to inducible damage repair responses. The cell wall damage response two-component system VxrAB of the gastrointestinal pathogen Vibrio cholerae promotes high-level β-lactam tolerance and controls a gene network encoding highly diverse functions, including negative control over multiple iron uptake systems. How this system contributes to tolerance is poorly understood. Here, we show that β-lactam antibiotics cause an increase in intracellular free iron levels and collateral oxidative damage, which is exacerbated in the ∆vxrAB mutant. Mutating major iron uptake systems dramatically increases ∆vxrAB tolerance to β-lactams. We propose that VxrAB reduces antibiotic-induced toxic iron and concomitant metabolic perturbations by downregulating iron uptake transporters and show that iron sequestration enhances tolerance against β-lactam therapy in a mouse model of cholera infection. Our results suggest that a microorganism's ability to counteract diverse antibiotic-induced stresses promotes high-level antibiotic tolerance and highlights the complex secondary responses elicited by antibiotics.
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Affiliation(s)
- Jung‐Ho Shin
- Weill Institute for Cell and Molecular BiologyCornell, UniversityIthacaNYUSA
- Department of MicrobiologyCornell UniversityIthacaNYUSA
| | - Donghui Choe
- Department of Biological SciencesKorea Advanced Institute of Science and TechnologyDaejeonKorea
- KI for the BioCenturyKorea Advanced Institute of Science and TechnologyDaejeonKorea
| | - Brett Ransegnola
- Weill Institute for Cell and Molecular BiologyCornell, UniversityIthacaNYUSA
- Department of MicrobiologyCornell UniversityIthacaNYUSA
| | - Hye‐Rim Hong
- Weill Institute for Cell and Molecular BiologyCornell, UniversityIthacaNYUSA
- Department of MicrobiologyCornell UniversityIthacaNYUSA
| | - Ikenna Onyekwere
- Weill Institute for Cell and Molecular BiologyCornell, UniversityIthacaNYUSA
- Department of MicrobiologyCornell UniversityIthacaNYUSA
| | - Trevor Cross
- Weill Institute for Cell and Molecular BiologyCornell, UniversityIthacaNYUSA
- Department of MicrobiologyCornell UniversityIthacaNYUSA
| | - Qiaojuan Shi
- Meinig School of Biomedical EngineeringCornell UniversityIthacaNYUSA
| | - Byung‐Kwan Cho
- Department of Biological SciencesKorea Advanced Institute of Science and TechnologyDaejeonKorea
- KI for the BioCenturyKorea Advanced Institute of Science and TechnologyDaejeonKorea
- Intelligent Synthetic Biology CenterDaejeonKorea
| | - Lars F Westblade
- Department of Pathology and Laboratory MedicineWeill Cornell MedicineNew YorkNYUSA
- Division of Infectious DiseasesDepartment of MedicineWeill Cornell MedicineNew YorkNYUSA
| | - Ilana L Brito
- Meinig School of Biomedical EngineeringCornell UniversityIthacaNYUSA
| | - Tobias Dörr
- Weill Institute for Cell and Molecular BiologyCornell, UniversityIthacaNYUSA
- Department of MicrobiologyCornell UniversityIthacaNYUSA
- Cornell Institute of Host‐Microbe Interactions and DiseaseCornell UniversityIthacaNYUSA
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17
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Bustamante V, González IA, Dreyse P, Palavecino CE. The mode of action of the PSIR-3 photosensitizer in the photodynamic inactivation of Klebsiella pneumoniae is by the production of type II ROS which activate RpoE-regulated extracytoplasmic factors. Photodiagnosis Photodyn Ther 2020; 32:102020. [PMID: 32977066 DOI: 10.1016/j.pdpdt.2020.102020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/30/2020] [Accepted: 09/18/2020] [Indexed: 12/21/2022]
Abstract
BACKGROUND Due to increased bacterial multi-drug resistance (MDR), there is an antibiotic depletion to treat infectious diseases. Consequently, other promising options have emerged, such as the antimicrobial photodynamic inactivation therapy (aPDI) based on photosensitizer (PS) compounds to produce light-activated local oxidative stress (photooxidative stress). However, there are scarce studies regarding the mode of action of PS compounds to induce photooxidative stress on pathogenic γ-proteobacteria such as MDR-Klebsiella pneumoniae. METHODOLOGY The mode of action exerted by the cationic Ir(III)-based PS (PSIR-3) to inhibit the growth of K. pneumoniae was analyzed. RT-qPCR determined the transcriptional response induced by PSIR-3 on bacteria treated with aPDI. The expression levels of genes associated with a bacterial oxidative response, such as oxyR and sodA, and the extracytoplasmic, regulators rpoE and hfq were determined. Also, were determined the transcriptional response of the extracytoplasmic factors mrkD, acrB, magA, and rmpA. RESULTS At 17 μW/cm2 photon flux and 4 μg/mL of the PSIR-3 compound, the K. pneumoniae growth was inhibited in 3 log10. Compared with untreated bacteria, the transcriptional response induced by PSIR-3 occurs via the extracytoplasmic sigma factor rpoE and hfq. In contrast, no participation in the oxyR pathway or induction of the sodA gene was observed. This response was accompanied by the upregulation of the extracytoplasmic virulence factors mrkD, magA, and rmpA. CONCLUSIONS PDI aPDI produced by PSIR-3 kills K. pneumoniae and may induce damage to the bacterial envelope. The bacterium tries to avoid this injury by activation of extracytoplasmic factors mediated through the rpoE regulon.
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Affiliation(s)
- Vanessa Bustamante
- Laboratorio de Microbiología Celular, Instituto de Investigación e Innovación en Salud, Facultad de Ciencias de la Salud, Universidad Central de Chile, Lord Cochrane 418, Post Cod: 8330546, Santiago, Chile.
| | - Iván A González
- Instituto de Investigación e Innovación en Salud, Facultad de Ciencias de la Salud, Universidad Central de Chile, Chile.
| | - Paulina Dreyse
- Departamento de Química, Universidad Técnica Federico Santa María, Av. España 1680, Casilla 2390123, Valparaíso, Chile.
| | - Christian Erick Palavecino
- Laboratorio de Microbiología Celular, Instituto de Investigación e Innovación en Salud, Facultad de Ciencias de la Salud, Universidad Central de Chile, Lord Cochrane 418, Post Cod: 8330546, Santiago, Chile.
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18
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Saenkham P, Ritter M, Donati GL, Subashchandrabose S. Copper primes adaptation of uropathogenic Escherichia coli to superoxide stress by activating superoxide dismutases. PLoS Pathog 2020; 16:e1008856. [PMID: 32845936 PMCID: PMC7478841 DOI: 10.1371/journal.ppat.1008856] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 09/08/2020] [Accepted: 08/04/2020] [Indexed: 12/26/2022] Open
Abstract
Copper and superoxide are used by the phagocytes to kill bacteria. Copper is a host effector encountered by uropathogenic Escherichia coli (UPEC) during urinary tract infection in a non-human primate model, and in humans. UPEC is exposed to higher levels of copper in the gut prior to entering the urinary tract. Effects of pre-exposure to copper on bacterial killing by superoxide has not been reported. We hypothesized that copper-replete E. coli is more sensitive to killing by superoxide in vitro, and in activated macrophages. We utilized wild-type UPEC strain CFT073, and its isogenic mutants lacking copper efflux systems, superoxide dismutases (SODs), regulators of a superoxide dismutase, and complemented mutants to address this question. Surprisingly, our results reveal that copper protects UPEC against killing by superoxide in vitro. This copper-dependent protection was amplified in the mutants lacking copper efflux systems. Increased levels of copper and manganese were detected in UPEC exposed to sublethal concentration of copper. Copper activated the transcription of sodA in a SoxR- and SoxS-dependent manner resulting in enhanced levels of SodA activity. Importantly, pre-exposure to copper increased the survival of UPEC within RAW264.7 and bone marrow-derived murine macrophages. Loss of SodA, but not SodB or SodC, in UPEC obliterated copper-dependent protection from superoxide in vitro, and from killing within macrophages. Collectively, our results suggest a model in which sublethal levels of copper trigger the activation of SodA and SodC through independent mechanisms that converge to promote the survival of UPEC from killing by superoxide. A major implication of our findings is that bacteria colonizing copper-rich milieus are primed for efficient detoxification of superoxide.
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Affiliation(s)
- Panatda Saenkham
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
| | - Matthew Ritter
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
| | - George L. Donati
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina, United States of America
| | - Sargurunathan Subashchandrabose
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
- * E-mail:
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19
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Smirnova GV, Tyulenev AV, Muzyka NG, Oktyabrsky ON. Study of the relationship between extracellular superoxide and glutathione production in batch cultures of Escherichia coli. Res Microbiol 2020; 171:301-310. [PMID: 32721518 DOI: 10.1016/j.resmic.2020.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/07/2020] [Accepted: 07/20/2020] [Indexed: 11/26/2022]
Abstract
Aerobically growing Escherichia coli generates superoxide flux into the periplasm via the oxidation of dihydromenaquinone and simultaneously carries out continuous transmembrane cycling of glutathione (GSH). Here we have shown that, under the conditions of a gradual decrease in dissolved oxygen (dO2), characteristic of batch culture, the global regulatory system ArcB/ArcA can play an important role in the coordinated control of extracellular superoxide and GSH fluxes and their interaction with intracellular antioxidant systems. The lowest superoxide production was observed in the menA and arcB mutants, while the atpA, atpC and atpE mutants generated superoxide 1.3-1.5 times faster than the parent. The share of exported glutathione in the ubiC, atpA, atpC, and atpE mutants was 2-3 times higher compared to the parent. A high direct correlation (r = 0.87, p = 0.01) between extracellular superoxide and GSH was revealed. The menA and arcB mutants, as well as the cydD mutant lacking the GSH export system CydDC, were not capable of GSH excretion with a decrease in dO2, which indicates a positive control of GSH export by ArcB. In contrast, ArcB downregulates sodA, therefore, an inverse correlation (r = -0.86, p = 0.013) between superoxide production and sodA expression was observed.
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Affiliation(s)
- Galina V Smirnova
- Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center, Russian Academy of Sciences, ul. Goleva 13, Perm, 614081, Russia.
| | - Aleksey V Tyulenev
- Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center, Russian Academy of Sciences, ul. Goleva 13, Perm, 614081, Russia.
| | - Nadezda G Muzyka
- Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center, Russian Academy of Sciences, ul. Goleva 13, Perm, 614081, Russia.
| | - Oleg N Oktyabrsky
- Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center, Russian Academy of Sciences, ul. Goleva 13, Perm, 614081, Russia.
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20
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Fontana J, Dong C, Kiattisewee C, Chavali VP, Tickman BI, Carothers JM, Zalatan JG. Effective CRISPRa-mediated control of gene expression in bacteria must overcome strict target site requirements. Nat Commun 2020; 11:1618. [PMID: 32238808 PMCID: PMC7113249 DOI: 10.1038/s41467-020-15454-y] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 03/04/2020] [Indexed: 11/09/2022] Open
Abstract
In bacterial systems, CRISPR-Cas transcriptional activation (CRISPRa) has the potential to dramatically expand our ability to regulate gene expression, but we lack predictive rules for designing effective gRNA target sites. Here, we identify multiple features of bacterial promoters that impose stringent requirements on CRISPRa target sites. Notably, we observe narrow, 2-4 base windows of effective sites with a periodicity corresponding to one helical turn of DNA, spanning ~40 bases and centered ~80 bases upstream of the TSS. However, we also identify two features suggesting the potential for broad scope: CRISPRa is effective at a broad range of σ70-family promoters, and an expanded PAM dCas9 allows the activation of promoters that cannot be activated by S. pyogenes dCas9. These results provide a roadmap for future engineering efforts to further expand and generalize the scope of bacterial CRISPRa.
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Affiliation(s)
- Jason Fontana
- Molecular Engineering & Sciences Institute, University of Washington, Seattle, 98195, WA, USA
| | - Chen Dong
- Department of Chemistry, University of Washington, Seattle, 98195, WA, USA
| | - Cholpisit Kiattisewee
- Molecular Engineering & Sciences Institute, University of Washington, Seattle, 98195, WA, USA
| | - Venkata P Chavali
- Department of Chemical Engineering, University of Washington, Seattle, 98195, WA, USA
| | - Benjamin I Tickman
- Molecular Engineering & Sciences Institute, University of Washington, Seattle, 98195, WA, USA
| | - James M Carothers
- Molecular Engineering & Sciences Institute, University of Washington, Seattle, 98195, WA, USA.
- Department of Chemical Engineering, University of Washington, Seattle, 98195, WA, USA.
- Center for Synthetic Biology, University of Washington, Seattle, 98195, WA, USA.
| | - Jesse G Zalatan
- Department of Chemistry, University of Washington, Seattle, 98195, WA, USA.
- Department of Chemical Engineering, University of Washington, Seattle, 98195, WA, USA.
- Center for Synthetic Biology, University of Washington, Seattle, 98195, WA, USA.
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21
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Valenzuela-Valderrama M, González IA, Palavecino CE. Photodynamic treatment for multidrug-resistant Gram-negative bacteria: Perspectives for the treatment of Klebsiella pneumoniae infections. Photodiagnosis Photodyn Ther 2019; 28:256-264. [PMID: 31505296 DOI: 10.1016/j.pdpdt.2019.08.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 08/09/2019] [Indexed: 12/25/2022]
Abstract
The emergence of multi-drug resistance for pathogenic bacteria is one of the most pressing global threats to human health in the 21st century. Hence, the availability of new treatment becomes indispensable to prevent morbidity and mortality caused by infectious agents. This article reviews the antimicrobial properties of photodynamic therapy (PDT), which is based on the use of photosensitizers compounds (PSs). The PSs are non-toxic small molecules, which induce oxidative stress only under excitation with light. Then, the PDT has the advantage to be locally activated using phototherapy devices. We focus on PDT for the Klebsiella pneumoniae, as an example of Gram-negative bacteria, due to its relevance as an agent of health-associated infections (HAI) and a multi-drug resistant bacteria. K. pneumoniae is a fermentative bacillus, member of the Enterobacteriaceae family, which is most commonly associated with producing infection of the urinary tract (UTI) and pneumonia. K. pneumoniae infections may occur in deep organs such as bladder or lungs tissues; therefore, activating light must get access or penetrate tissues with sufficient power to produce effective PDT. Consequently, the rationale for selecting the most appropriate PSs, as well as photodynamic devices and photon fluence doses, were reviewed. Also, the mechanisms by which PDT activates the immune system and its importance to eradicate the infection successfully, are discussed.
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Affiliation(s)
- Manuel Valenzuela-Valderrama
- Laboratorio de Microbiología Celular, Instituto de Investigación e Innovación en Salud, Facultad de Ciencias de la Salud, Universidad Central de Chile, Chile; Centro de Estudios Avanzados en Enfermedades Crónicas (ACCDiS), Independencia, Santiago 8380000, Chile.
| | - Iván Alonzo González
- Instituto de Investigación e Innovación en Salud, Facultad de Ciencias de la Salud, Universidad Central de Chile, Chile.
| | - Christian Erick Palavecino
- Laboratorio de Microbiología Celular, Instituto de Investigación e Innovación en Salud, Facultad de Ciencias de la Salud, Universidad Central de Chile, Chile.
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22
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Nóbrega CS, Pauleta SR. Reduction of hydrogen peroxide in gram-negative bacteria - bacterial peroxidases. Adv Microb Physiol 2019; 74:415-464. [PMID: 31126534 DOI: 10.1016/bs.ampbs.2019.02.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Bacteria display an array of enzymes to detoxify reactive oxygen species that cause damage to DNA and to other biomolecules leading to cell death. Hydrogen peroxide is one of these species, with endogenous and exogenous sources, such as lactic acid bacteria, oxidative burst of the immune system or chemical reactions at oxic-anoxic interfaces. The enzymes that detoxify hydrogen peroxide will be the focus of this review, with special emphasis on bacterial peroxidases that reduce hydrogen peroxide to water. Bacterial peroxidases are periplasmic cytochromes with either two or three c-type haems, which have been classified as classical and non-classical bacterial peroxidases, respectively. Most of the studies have been focus on the classical bacterial peroxidases, showing the presence of a reductive activation in the presence of calcium ions. Mutagenesis studies have clarified the catalytic mechanism of this enzyme and were used to propose an intramolecular electron transfer pathway, with far less being known about the intermolecular electron transfer that occurs between reduced electron donors and the enzyme. The physiological function of these enzymes was not very clear until it was shown, for the non-classical bacterial peroxidase, that this enzyme is required for the bacteria to use hydrogen peroxide as terminal electron acceptor under anoxic conditions. These non-classical bacterial peroxidases are quinol peroxidases that do not require reductive activation but need calcium ions to attain maximum activity and share similar catalytic intermediates with the classical bacterial peroxidases.
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Affiliation(s)
- Cláudia S Nóbrega
- Microbial Stress Lab, UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Sofia R Pauleta
- Microbial Stress Lab, UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
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Najmuldeen H, Alghamdi R, Alghofaili F, Yesilkaya H. Functional assessment of microbial superoxide dismutase isozymes suggests a differential role for each isozyme. Free Radic Biol Med 2019; 134:215-228. [PMID: 30658083 DOI: 10.1016/j.freeradbiomed.2019.01.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 12/06/2018] [Accepted: 01/14/2019] [Indexed: 12/21/2022]
Abstract
Microbes can have multiple enzymes that are able to catalyse the same enzymatic reactions but may differ in structure. These are known as isozymes. It is assumed that isozymes have the same functional role for cells. Contrary to this assumption, we hypothesised that isozymes can confer different functions for microbial cells despite catalysing the same reactions. To test this hypothesis, we studied the role of superoxide dismutases (SOD) in Klebsiella pneumoniae, the causative agent of several nosocomial and community-acquired infections, in infection relevant assays. SODs are responsible for detoxification of toxic superoxide radicals. K. pneumoniae genome contains three superoxide dismutase genes, sodA, sodB, and sodC coding for Mn-, Fe- and CuZn- co-factored SODs, respectively. By creating and testing single, double, and triple SOD mutants, we investigated the regulatory interactions among SOD and determined the role of each isozyme in oxidative stress resistance, biofilm formation, cell morphology, metabolism, and in vivo colonization and persistence. Our results demonstrate that SOD isozymes in K. pneumoniae have unique roles beyond oxidative stress resistance, and there is a regulatory interplay among SODs.
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Affiliation(s)
- Hastyar Najmuldeen
- Department of Infection, Immunity and Inflammation, University of Leicester, University Road, Leicester LE1 9HN, UK; Department of Biology, College of Science, University of Sulaimani, Sulaymaniyah, Kurdistan Region, Iraq
| | - Rashed Alghamdi
- Department of Infection, Immunity and Inflammation, University of Leicester, University Road, Leicester LE1 9HN, UK
| | - Fayez Alghofaili
- Department of Infection, Immunity and Inflammation, University of Leicester, University Road, Leicester LE1 9HN, UK; Department of Biology, College of Science, Majmaah University, Majmaah 11952, Saudi Arabia
| | - Hasan Yesilkaya
- Department of Infection, Immunity and Inflammation, University of Leicester, University Road, Leicester LE1 9HN, UK.
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Cabrejos DAL, Alexandrino AV, Pereira CM, Mendonça DC, Pereira HD, Novo-Mansur MTM, Garratt RC, Goto LS. Structural characterization of a pathogenicity-related superoxide dismutase codified by a probably essential gene in Xanthomonas citri subsp. citri. PLoS One 2019; 14:e0209988. [PMID: 30615696 PMCID: PMC6322740 DOI: 10.1371/journal.pone.0209988] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 12/14/2018] [Indexed: 11/24/2022] Open
Abstract
Citrus canker is a plant disease caused by the bacteria Xanthomonas citri subsp. citri that affects all domestic varieties of citrus. Some annotated genes from the X. citri subsp. citri genome are assigned to an interesting class named "pathogenicity, virulence and adaptation". Amongst these is sodM, which encodes for the gene product XcSOD, one of four superoxide dismutase homologs predicted from the genome. SODs are widespread enzymes that play roles in the oxidative stress response, catalyzing the degradation of the deleterious superoxide radical. In Xanthomonas, SOD has been associated with pathogenesis as a counter measure against the plant defense response. In this work we initially present the 1.8 Å crystal structure of XcSOD, a manganese containing superoxide dismutase from Xanthomonas citri subsp. citri. The structure bears all the hallmarks of a dimeric member of the MnSOD family, including the conserved hydrogen-bonding network residues. Despite the apparent gene redundancy, several attempts to obtain a sodM deletion mutant were unsuccessful, suggesting the encoded protein to be essential for bacterial survival. This intriguing observation led us to extend our structural studies to the remaining three SOD homologs, for which comparative models were built. The models imply that X. citri subsp. citri produces an iron-containing SOD which is unlikely to be catalytically active along with two conventional Cu,ZnSODs. Although the latter are expected to possess catalytic activity, we propose they may not be able to replace XcSOD for reasons such as distinct subcellular compartmentalization or differential gene expression in pathogenicity-inducing conditions.
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Affiliation(s)
- Diego Antonio Leonardo Cabrejos
- Laboratório de Biologia Estrutural, Grupo de Cristalografia, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil
| | - André Vessoni Alexandrino
- Laboratório de Bioquímica e Biologia Molecular Aplicada—LBBMA, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brazil
| | - Camila Malvessi Pereira
- Laboratório de Bioquímica e Biologia Molecular Aplicada—LBBMA, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brazil
| | - Deborah Cezar Mendonça
- Laboratório de Biologia Estrutural, Grupo de Cristalografia, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil
| | - Humberto D'Muniz Pereira
- Laboratório de Biologia Estrutural, Grupo de Cristalografia, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil
| | - Maria Teresa Marques Novo-Mansur
- Laboratório de Bioquímica e Biologia Molecular Aplicada—LBBMA, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brazil
| | - Richard Charles Garratt
- Laboratório de Biologia Estrutural, Grupo de Cristalografia, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil
| | - Leandro Seiji Goto
- Laboratório de Bioquímica e Biologia Molecular Aplicada—LBBMA, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brazil
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Stewart LJ, Thaqi D, Kobe B, McEwan AG, Waldron KJ, Djoko KY. Handling of nutrient copper in the bacterial envelope. Metallomics 2019; 11:50-63. [DOI: 10.1039/c8mt00218e] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The insertion of copper into bacterial cuproenzymesin vivodoes not always require a copper-binding metallochaperone – why?
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Affiliation(s)
- Louisa J. Stewart
- Institute for Cell and Molecular Biosciences
- Newcastle University
- Newcastle upon Tyne
- UK
| | - Denis Thaqi
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre
- The University of Queensland
- St Lucia
- Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre
- The University of Queensland
- St Lucia
- Australia
- Institute for Molecular Bioscience
| | - Alastair G. McEwan
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre
- The University of Queensland
- St Lucia
- Australia
| | - Kevin J. Waldron
- Institute for Cell and Molecular Biosciences
- Newcastle University
- Newcastle upon Tyne
- UK
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26
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Zinc-dependent substrate-level phosphorylation powers Salmonella growth under nitrosative stress of the innate host response. PLoS Pathog 2018; 14:e1007388. [PMID: 30365536 PMCID: PMC6221366 DOI: 10.1371/journal.ppat.1007388] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 11/07/2018] [Accepted: 10/07/2018] [Indexed: 12/13/2022] Open
Abstract
The metabolic processes that enable the replication of intracellular Salmonella under nitrosative stress conditions engendered in the innate response of macrophages are poorly understood. A screen of Salmonella transposon mutants identified the ABC-type high-affinity zinc uptake system ZnuABC as a critical determinant of the adaptation of Salmonella to the nitrosative stress generated by the enzymatic activity of inducible nitric oxide (NO) synthase of mononuclear phagocytic cells. NO limits the virulence of a znuB mutant in an acute murine model of salmonellosis. The ZnuABC transporter is crucial for the glycolytic function of fructose bisphosphate aldolase, thereby fueling growth of Salmonella during nitrosative stress produced in the innate response of macrophages. Our investigations demonstrate that glycolysis mediates resistance of Salmonella to the antimicrobial activity of NO produced in an acute model of infection. The ATP synthesized by substrate-level phosphorylation at the payoff phase of glycolysis and acetate fermentation powers the replication of Salmonella experiencing high levels of nitrosative stress. In contrast, despite its high potential for ATP synthesis, oxidative phosphorylation is a major target of inhibition by NO and contributes little to the antinitrosative defenses of intracellular Salmonella. Our investigations have uncovered a previously unsuspected conjunction between zinc homeostasis, glucose metabolism and cellular energetics in the adaptation of intracellular Salmonella to the reactive nitrogen species synthesized in the innate host response. Microbial pathogens are exposed to multiple antimicrobial defenses during their associations with host cells. Nitric oxide generated in the innate response exerts widespread antimicrobial activity against a variety of pathogenic microorganisms. Nitric oxide has high affinity for metal groups of terminal cytochromes of the respiratory chain, and thus nitrosative stress exerts extreme deleterious actions against the cellular energetics that rely on oxidative phosphorylation. Intracellular Salmonella have resolved this dilemma by satisfying a significant portion of their energetic demands via substrate level phosphorylation in the payoff phase of glycolysis and acetate fermentation. A high affinity zinc uptake system promotes antinitrosative defense of intracellular Salmonella by in great part supporting the enzymatic activity of an essential enzyme in the preparatory phase of glycolysis. Our research provides novel insights into the metabolic and energetic adaptations that allow a bacterial pathogen to thrive in the midst of the innate host response of vertebrate cells.
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Rasheed W, Perveen S, Mustafa G, Shah MR, Ahmed S, Uzzaman S. Impact of Cu(II)-doping on the vulnerability of Escherichia coli ATCC 10536 revealed by Atomic Force Microscopy. Micron 2018; 110:73-78. [PMID: 29772475 DOI: 10.1016/j.micron.2018.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 05/02/2018] [Accepted: 05/03/2018] [Indexed: 11/28/2022]
Abstract
E. coli strain is a gram-negative bacterium known to induce both extra-intestinal infections and intestinal infections. For survival of microbes, metal intake and accessibility should be according to their physiological requirements. Peculiarly, copper homeostasis is critical for E. coli survival and growth. Therefore in this study, an extensive work is conducted to investigate the impact of Cu(II)-doping on the susceptibility of Escherichia coli ATCC 10536 against Cu(II)-selective Cefaclor-silver nanoconjugates (i.e., Cf-AgNPs) and its organic precursor (i.e. Cefaclor). At first, the maximal non-cytotoxic dose of Cu(II) that was sub-lethal for Escherichia coli was determined by MTT assay and was found to be 100 μg/L. Afterwards, MICs of Cf-AgNPs and Cefaclor against controlled and Cu(II)-doped E. coli cells were determined by using Agar well diffusion method. The susceptibility of E. coli cells against Cf-AgNPs was increased upon Cu(II) doping, whereas the bactericidal activity of Cefaclor against Cu(II)-doped E. coli cells was retarded due to hydrolysis. In addition, morphological changes induced in controlled and Cu(II)-doped samples of E. coli after treatment with Cefaclor and Cf-AgNPs were also monitored by Atomic force microscopy (AFM). The obtained results from both Agar well diffusion method and AFM confirmed that Cf-AgNPs are more effective against Cu(II)-doped Escherichia coli. Moreover, thermal profile of Cu(II)-selective Cf-AgNPs was also demonstrated by TGA and DSC. This study can be an important part of the relevant state-of-the-art. Indeed, further clinical studies are necessary to determine the relevant role of Cf-AgNPs compared with that of the Cefaclor now available.
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Affiliation(s)
- Wasia Rasheed
- Department of Applied Chemistry and Chemical Technology, University of Karachi, Karachi, 75270, Pakistan; H.E.J. Research Institute of Chemistry, International Centre for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan.
| | - Samina Perveen
- H.E.J. Research Institute of Chemistry, International Centre for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Ghulam Mustafa
- H.E.J. Research Institute of Chemistry, International Centre for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Muhammad Raza Shah
- H.E.J. Research Institute of Chemistry, International Centre for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Shakil Ahmed
- H.E.J. Research Institute of Chemistry, International Centre for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Sami Uzzaman
- H.E.J. Research Institute of Chemistry, International Centre for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
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Lemire J, Alhasawi A, Appanna VP, Tharmalingam S, Appanna VD. Metabolic defence against oxidative stress: the road less travelled so far. J Appl Microbiol 2017; 123:798-809. [PMID: 28609580 DOI: 10.1111/jam.13509] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 05/30/2017] [Accepted: 06/05/2017] [Indexed: 12/28/2022]
Abstract
Bacteria have survived, and many have thrived, since antiquity in the presence of the highly-reactive chalcogen-oxygen (O2 ). They are known to evoke intricate strategies to defend themselves from the reactive by-products of oxygen-reactive oxygen species (ROS). Many of these detoxifying mechanisms have been extensively characterized; superoxide dismutase, catalases, alkyl hydroperoxide reductase and the glutathione (GSH)-cycling system are responsible for neutralizing specific ROS. Meanwhile, a pool of NADPH-the reductive engine of many ROS-combating enzymes-is maintained by metabolic enzymes including, but not exclusively, glucose-6 phosphate dehydrogenase (G6PDH) and NADP-dependent isocitrate dehydrogenase (ICDH-NADP). So, it is not surprising that evidence continues to emerge demonstrating the pivotal role metabolism plays in mitigating ROS toxicity. Stemming from its ability to concurrently decrease the production of the pro-oxidative metabolite, NADH, while augmenting the antioxidative metabolite, NADPH, metabolism is the fulcrum of cellular redox potential. In this review, we will discuss the mounting evidence positioning metabolism and metabolic shifts observed during oxidative stress, as critical strategies microbes utilize to thrive in environments that are rife with ROS. The contribution of ketoacids-moieties capable of non-enzymatic decarboxylation in the presence of oxidants-as ROS scavengers will be elaborated alongside the metabolic pathways responsible for their homeostases. Further, the signalling role of the carboxylic acids generated following the ketoacid-mediated detoxification of the ROS will be commented on within the context of oxidative stress.
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Affiliation(s)
- J Lemire
- The Biofilm Research Group, The Department of Biological Sciences, The University of Calgary, Calgary, AB, Canada
| | - A Alhasawi
- Faculty of Science & Engineering, Laurentian University, Sudbury, ON, Canada
| | - V P Appanna
- Faculty of Science & Engineering, Laurentian University, Sudbury, ON, Canada
| | - S Tharmalingam
- Faculty of Science & Engineering, Laurentian University, Sudbury, ON, Canada
| | - V D Appanna
- Faculty of Science & Engineering, Laurentian University, Sudbury, ON, Canada
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Stress Responses, Adaptation, and Virulence of Bacterial Pathogens During Host Gastrointestinal Colonization. Microbiol Spectr 2017; 4. [PMID: 27227312 DOI: 10.1128/microbiolspec.vmbf-0007-2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Invading pathogens are exposed to a multitude of harmful conditions imposed by the host gastrointestinal tract and immune system. Bacterial defenses against these physical and chemical stresses are pivotal for successful host colonization and pathogenesis. Enteric pathogens, which are encountered due to the ingestion of or contact with contaminated foods or materials, are highly successful at surviving harsh conditions to colonize and cause the onset of host illness and disease. Pathogens such as Campylobacter, Helicobacter, Salmonella, Listeria, and virulent strains of Escherichia have evolved elaborate defense mechanisms to adapt to the diverse range of stresses present along the gastrointestinal tract. Furthermore, these pathogens contain a multitude of defenses to help survive and escape from immune cells such as neutrophils and macrophages. This chapter focuses on characterized bacterial defenses against pH, osmotic, oxidative, and nitrosative stresses with emphasis on both the direct and indirect mechanisms that contribute to the survival of each respective stress response.
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Commensal-to-pathogen transition: One-single transposon insertion results in two pathoadaptive traits in Escherichia coli -macrophage interaction. Sci Rep 2017; 7:4504. [PMID: 28674418 PMCID: PMC5495878 DOI: 10.1038/s41598-017-04081-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 05/09/2017] [Indexed: 01/01/2023] Open
Abstract
Escherichia coli is both a harmless commensal in the intestines of many mammals, as well as a dangerous pathogen. The evolutionary paths taken by strains of this species in the commensal-to-pathogen transition are complex and can involve changes both in the core genome, as well in the pan-genome. One way to understand the likely paths that a commensal strain of E. coli takes when evolving pathogenicity is through experimentally evolving the strain under the selective pressures that it will have to withstand as a pathogen. Here, we report that a commensal strain, under continuous pressure from macrophages, recurrently acquired a transposable element insertion, which resulted in two key phenotypic changes: increased intracellular survival, through the delay of phagosome maturation and increased ability to escape macrophages. We further show that the acquisition of the pathoadaptive traits was accompanied by small but significant changes in the transcriptome of macrophages upon infection. These results show that under constant pressures from a key component of the host immune system, namely macrophage phagocytosis, commensal E. coli rapidly acquires pathoadaptive mutations that cause transcriptome changes associated to the host-microbe duet.
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31
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Hassan KA, Pederick VG, Elbourne LDH, Paulsen IT, Paton JC, McDevitt CA, Eijkelkamp BA. Zinc stress induces copper depletion in Acinetobacter baumannii. BMC Microbiol 2017; 17:59. [PMID: 28284195 PMCID: PMC5346208 DOI: 10.1186/s12866-017-0965-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 02/24/2017] [Indexed: 12/18/2022] Open
Abstract
Background The first row transition metal ions zinc and copper are essential to the survival of many organisms, although in excess these ions are associated with significant toxicity. Here, we examined the impact of zinc and copper stress on Acinetobacter baumannii, a common opportunistic pathogen. Results We show that extracellular zinc stress induces a copper-specific depletion phenotype in A. baumannii ATCC 17978. Supplementation with copper not only fails to rescue this phenotype, but further exacerbates the copper depletion. Extensive analysis of the A. baumannii ATCC 17978 genome identified 13 putative zinc/copper resistance efflux pumps. Transcriptional analyses show that four of these transporters are responsive to zinc stress, five to copper stress and seven to the combination of zinc and copper stress, thereby revealing a likely foundation for the zinc-induced copper starvation in A. baumannii. In addition, we show that zinc and copper play crucial roles in management of oxidative stress and the membrane composition of A. baumannii. Further, we reveal that zinc and copper play distinct roles in macrophage-mediated killing of this pathogen. Conclusions Collectively, this study supports the targeting of metal ion homeostatic mechanisms as an effective antimicrobial strategy against multi-drug resistant bacterial pathogens. Electronic supplementary material The online version of this article (doi:10.1186/s12866-017-0965-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Karl A Hassan
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Victoria G Pederick
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Liam D H Elbourne
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Ian T Paulsen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - James C Paton
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Christopher A McDevitt
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia.
| | - Bart A Eijkelkamp
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia.
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Increasing dissolved-oxygen disrupts iron homeostasis in production cultures of Escherichia coli. Antonie van Leeuwenhoek 2016; 110:115-124. [PMID: 27757702 DOI: 10.1007/s10482-016-0781-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 10/05/2016] [Indexed: 12/20/2022]
Abstract
The damaging effect of high oxygen concentration on growth of Escherichia coli is well established. Over-oxygenation increases the intracellular concentration of reactive oxygen species (ROS), causing the destruction of the [4Fe-4S] cluster of dehydratases and limiting the biosynthesis of both branched-chain amino acids and nicotinamide adenine dinucleotide. A key enzyme that reduces the damaging effect of superoxide is superoxide dismutase (SOD). Its transcriptional regulation is controlled by global transcription regulators that respond to changes in oxygen and iron concentrations and pH. Production of biological compounds from E. coli is currently achieved using cultures grown to high cell densities which require oxygen-enriched air supply. It is, therefore, important to study the effect of over-oxygenation on E. coli metabolism and the bacterial protecting mechanism. The effect of over-oxygenation on the superoxide dismutase regulation system was evaluated in cultures grown in a bioreactor by increasing the oxygen concentration from 30 to 300 % air saturation. Following the change in the dissolved oxygen (DO), the expression of sodC, the periplasmic CuZn-containing SOD, and sodA, the cytosolic Mn-containing SOD, was higher in all the tested strains, while the expression of the sodB, the cytosolic Fe-containing SOD, was lower. The down-regulation of the sodB was found to be related to the activation of the small RNA RyhB. It was revealed that iron homeostasis, in particular ferric iron, was involved in the RyhB activation and in sodB regulation but not in sodA. Supplementation of amino acids to the culture medium reduced the intracellular ROS accumulation and reduced the activation of both SodA and SodC following the increase in the oxygen concentration. The study provides evidence that at conditions of over-oxygenation, sodA and sodC are strongly regulated by the amount of ROS, in particular superoxide; and sodB is regulated by iron availability through the small RNA RyhB. In addition, information on the impact of NADH, presence of amino acids and type of iron on SOD regulation, and consequently, on the ROS concentration is provided.
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Chaithawiwat K, Vangnai A, McEvoy JM, Pruess B, Krajangpan S, Khan E. Role of oxidative stress in inactivation of Escherichia coli BW25113 by nanoscale zero-valent iron. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 565:857-862. [PMID: 26953142 DOI: 10.1016/j.scitotenv.2016.02.191] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 02/26/2016] [Accepted: 02/27/2016] [Indexed: 06/05/2023]
Abstract
An Escherichia coli BW25113 wildtype strain and mutant strains lacking genes that protect against oxidative stress were examined at different growth phases for susceptibility to zero-valent iron (nZVI). Viability of cells was determined by the plate count method. All mutant strains were more susceptible than the wild type strain to nZVI; however, susceptibility differed among the mutant strains. Consistent with the role of rpoS as a global stress regulator, an rpoS gene knockout mutant exhibited the greatest susceptibility to nZVI under the majority of conditions tested (except exponential and declining phases at longer exposure time). Mutants lacking genes encoding the inducible and constitutively expressed cytosolic superoxide dismutases, sodA and sodB, respectively, were more susceptible to nZVI than a mutant lacking the gene encoding sodC, a periplasmic superoxide dismutase. This suggests that nZVI induces oxidative stress inside the cells via superoxide generation. Quantitative polymerase chain reaction was used to examine the expression of katG, a gene encoding the catalase-peroxidase enzyme, in nZVI-treated E. coli at different growth phases. Results showed that nZVI repressed the expression of katG in all but lag phases.
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Affiliation(s)
- Krittanut Chaithawiwat
- International Postgraduate Programs in Environmental Management, Graduate School Chulalongkorn University, Bangkok 10330, Thailand; Environmental and Conservation Sciences, North Dakota State University, Fargo, ND 58108, USA
| | - Alisa Vangnai
- Department of Biochemistry, Chulalongkorn University, Bangkok 10330, Thailand
| | - John M McEvoy
- Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, ND 58108, USA
| | - Birgit Pruess
- Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, ND 58108, USA
| | | | - Eakalak Khan
- Department of Civil and Environmental Engineering, North Dakota State University, Fargo, ND 58108, USA.
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34
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The Crystal Structure of Peroxiredoxin Asp f3 Provides Mechanistic Insight into Oxidative Stress Resistance and Virulence of Aspergillus fumigatus. Sci Rep 2016; 6:33396. [PMID: 27624005 PMCID: PMC5022050 DOI: 10.1038/srep33396] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 08/03/2016] [Indexed: 12/22/2022] Open
Abstract
Invasive aspergillosis and other fungal infections occur in immunocompromised individuals, including patients who received blood-building stem cell transplants, patients with chronic granulomatous disease (CGD), and others. Production of reactive oxygen species (ROS) by immune cells, which incidentally is defective in CGD patients, is considered to be a fundamental process in inflammation and antifungal immune response. Here we show that the peroxiredoxin Asp f3 of Aspergillus fumigatus inactivates ROS. We report the crystal structure and the catalytic mechanism of Asp f3, a two-cysteine type peroxiredoxin. The latter exhibits a thioredoxin fold and a homodimeric structure with two intermolecular disulfide bonds in its oxidized state. Replacement of the Asp f3 cysteines with serine residues retained its dimeric structure, but diminished Asp f3's peroxidase activity, and extended the alpha-helix with the former peroxidatic cysteine residue C61 by six residues. The asp f3 deletion mutant was sensitive to ROS, and this phenotype was rescued by ectopic expression of Asp f3. Furthermore, we showed that deletion of asp f3 rendered A. fumigatus avirulent in a mouse model of pulmonary aspergillosis. The conserved expression of Asp f3 homologs in medically relevant molds and yeasts prompts future evaluation of Asp f3 as a potential therapeutic target.
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Ma Z, Russo VC, Rabadi SM, Jen Y, Catlett SV, Bakshi CS, Malik M. Elucidation of a mechanism of oxidative stress regulation in Francisella tularensis live vaccine strain. Mol Microbiol 2016; 101:856-78. [PMID: 27205902 DOI: 10.1111/mmi.13426] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2016] [Indexed: 12/21/2022]
Abstract
Francisella tularensis causes a lethal human disease known as tularemia. As an intracellular pathogen, Francisella survives and replicates in phagocytic cells, such as macrophages. However, to establish an intracellular niche, Francisella must overcome the oxidative stress posed by the reactive oxygen species (ROS) produced by the infected macrophages. OxyR and SoxR/S are two well-characterized transcriptional regulators of oxidative stress responses in several bacterial pathogens. Only the OxyR homolog is present in F. tularensis, while the SoxR homologs are absent. The functional role of OxyR has not been established in F. tularensis. We demonstrate that OxyR regulates oxidative stress responses and provides resistance against ROS, thereby contributing to the survival of the F. tularensis subsp. holarctica live vaccine strain (LVS) in macrophages and epithelial cells and contributing to virulence in mice. Proteomic analysis reveals the differential production of 128 proteins in the oxyR gene deletion mutant, indicating its global regulatory role in the oxidative stress response of F. tularensis. Moreover, OxyR regulates the transcription of the primary antioxidant enzyme genes by binding directly to their putative promoter regions. This study demonstrates that OxyR is an important virulence factor and transcriptional regulator of the oxidative stress response of the F. tularensis LVS.
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Affiliation(s)
- Zhuo Ma
- Department of Basic and Social Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, USA
| | - Vincenzo C Russo
- Department of Basic and Social Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, USA
| | - Seham M Rabadi
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, USA
| | - Yu Jen
- Department of Pathology, Westchester Medical Center, Valhalla, NY, USA
| | - Sally V Catlett
- Department of Basic and Social Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, USA
| | | | - Meenakshi Malik
- Department of Basic and Social Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, USA
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Stolle P, Hou B, Brüser T. The Tat Substrate CueO Is Transported in an Incomplete Folding State. J Biol Chem 2016; 291:13520-8. [PMID: 27129241 DOI: 10.1074/jbc.m116.729103] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Indexed: 11/06/2022] Open
Abstract
In Escherichia coli, cytoplasmic copper ions are toxic to cells even at the lowest concentrations. As a defense strategy, the cuprous oxidase CueO is secreted into the periplasm to oxidize the more membrane-permeable and toxic Cu(I) before it can enter the cytoplasm. CueO itself is a multicopper oxidase that requires copper for activity. Because it is transported by the twin-arginine translocation (Tat) pathway, which transports folded proteins, a requirement for cofactor assembly before translocation has been discussed. Here we show that CueO is transported as an apo-protein. Periplasmic CueO was readily activated by the addition of copper ions in vitro or under copper stress conditions in vivo Cytoplasmic CueO did not contain copper, even under copper stress conditions. In vitro Tat transport proved that the cofactor assembly was not required for functional Tat transport of CueO. Due to the post-translocational activation of CueO, this enzyme contributes to copper resistance not only by its cuprous oxidase activity but also by chelation of copper ions before they can enter the cytoplasm. Apo-CueO was indistinguishable from holo-CueO in terms of secondary structural elements. Importantly, the binding of copper to apo-CueO greatly stabilized the protein, indicating a transformation from an open or flexible domain arrangement with accessible copper sites to a closed structure with deeply buried copper ions. CueO is thus the first example for a natural Tat substrate of such incomplete folding state. The Tat system may need to transport flexibly folded proteins in any case when cofactor assembly or quaternary structure formation occurs after transport.
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Affiliation(s)
- Patrick Stolle
- From the Institute of Microbiology, Leibniz Universität Hannover, Herrenhäuser Strasse 2, 30419 Hannover, Germany
| | - Bo Hou
- From the Institute of Microbiology, Leibniz Universität Hannover, Herrenhäuser Strasse 2, 30419 Hannover, Germany
| | - Thomas Brüser
- From the Institute of Microbiology, Leibniz Universität Hannover, Herrenhäuser Strasse 2, 30419 Hannover, Germany
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Rodríguez-Rojas F, Díaz-Vásquez W, Undabarrena A, Muñoz-Díaz P, Arenas F, Vásquez C. Mercury-mediated cross-resistance to tellurite in Pseudomonas spp. isolated from the Chilean Antarctic territory. Metallomics 2016; 8:108-17. [DOI: 10.1039/c5mt00256g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Mercury salts and tellurite are among the most toxic compounds for microorganisms on Earth.
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Affiliation(s)
- F. Rodríguez-Rojas
- Laboratorio de Microbiología Molecular
- Facultad de Química y Biología
- Universidad de Santiago de Chile
- Santiago, Chile
| | - W. Díaz-Vásquez
- Laboratorio de Microbiología Molecular
- Facultad de Química y Biología
- Universidad de Santiago de Chile
- Santiago, Chile
- Facultad de Ciencias de la Salud
| | - A. Undabarrena
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental
- Facultad de Química, & Centro de Biotecnología Daniel Alkalay Lowitt
- Universidad Técnica Federico Santa María
- Valparaíso, Chile
| | - P. Muñoz-Díaz
- Laboratorio de Microbiología Molecular
- Facultad de Química y Biología
- Universidad de Santiago de Chile
- Santiago, Chile
| | - F. Arenas
- Laboratorio de Microbiología Molecular
- Facultad de Química y Biología
- Universidad de Santiago de Chile
- Santiago, Chile
| | - C. Vásquez
- Laboratorio de Microbiología Molecular
- Facultad de Química y Biología
- Universidad de Santiago de Chile
- Santiago, Chile
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Albarracín VH, Gärtner W, Farias ME. Forged Under the Sun: Life and Art of Extremophiles from Andean Lakes. Photochem Photobiol 2015; 92:14-28. [PMID: 26647770 DOI: 10.1111/php.12555] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 10/09/2015] [Accepted: 11/05/2015] [Indexed: 12/25/2022]
Abstract
High-altitude Andean lakes (HAAL) are a treasure chest for microbiological research in South America. Their indigenous microbial communities are exposed to extremely high UV irradiation and to multiple chemical extremes (Arsenic, high salt content, alkalinity). Microbes are found both, free-living or associated into microbial mats with different degrees of mineralization and lithification, including unique modern stromatolites located at 3570 m above sea level. Characterization of these polyextremophilic microbes began only recently, employing morphological and phylogenetic methods as well as high-throughput sequencing and proteomics approach. Aside from providing a general overview on microbial communities, special attention is given to various survival strategies; HAAL's microbes present a complex system of shared genetic and physiological mechanisms (UV-resistome) based on UV photoreceptors and stress sensors with their corresponding response regulators, UV avoidance and protection strategies, damage tolerance and UV damage repair. Molecular information will be provided for what is, so far the most studied HAAL molecule, a CPD-Class I photolyase from Acinetobacter Ver3 (Laguna Verde, 4400 m). This work further proposes some strategies that make an appeal for the preservation of HAAL, a highly fragile environment that offers promising and ample research possibilities.
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Affiliation(s)
- Virginia Helena Albarracín
- Planta Piloto de Procesos Industriales y Microbiológicos (PROIMI), CCT, CONICET, Tucumán, Argentina.,Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, Tucumán, Argentina
| | - Wolfgang Gärtner
- Max-Planck-Institute for Chemical Energy Conversion, Mülheim, Germany
| | - María Eugenia Farias
- Planta Piloto de Procesos Industriales y Microbiológicos (PROIMI), CCT, CONICET, Tucumán, Argentina
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Abstract
The ancestors of Escherichia coli and Salmonella ultimately evolved to thrive in air-saturated liquids, in which oxygen levels reach 210 μM at 37°C. However, in 1976 Brown and colleagues reported that some sensitivity persists: growth defects still become apparent when hyperoxia is imposed on cultures of E. coli. This residual vulnerability was important in that it raised the prospect that normal levels of oxygen might also injure bacteria, albeit at reduced rates that are not overtly toxic. The intent of this article is both to describe the threat that molecular oxygen poses for bacteria and to detail what we currently understand about the strategies by which E. coli and Salmonella defend themselves against it. E. coli mutants that lack either superoxide dismutases or catalases and peroxidases exhibit a variety of growth defects. These phenotypes constitute the best evidence that aerobic cells continually generate intracellular superoxide and hydrogen peroxide at potentially lethal doses. Superoxide has reduction potentials that allow it to serve in vitro as either a weak univalent reductant or a stronger univalent oxidant. The addition of micromolar hydrogen peroxide to lab media will immediately block the growth of most cells, and protracted exposure will result in the loss of viability. The need for inducible antioxidant systems seems especially obvious for enteric bacteria, which move quickly from the anaerobic gut to fully aerobic surface waters or even to ROS-perfused phagolysosomes. E. coli and Salmonella have provided two paradigmatic models of oxidative-stress responses: the SoxRS and OxyR systems.
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Smirnova GV, Muzyka NG, Ushakov VY, Tyulenev AV, Oktyabrsky ON. Extracellular superoxide provokes glutathione efflux from Escherichia coli cells. Res Microbiol 2015; 166:609-17. [DOI: 10.1016/j.resmic.2015.07.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 06/23/2015] [Accepted: 07/06/2015] [Indexed: 11/28/2022]
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Tidhar A, Rushing MD, Kim B, Slauch JM. Periplasmic superoxide dismutase SodCI of Salmonella binds peptidoglycan to remain tethered within the periplasm. Mol Microbiol 2015; 97:832-843. [PMID: 25998832 DOI: 10.1111/mmi.13067] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2015] [Indexed: 11/29/2022]
Abstract
Salmonellae survive and propagate in macrophages to cause serious systemic disease. Periplasmic superoxide dismutase plays a critical role in this survival by combating phagocytic superoxide. Salmonella Typhimurium strain 14028 produces two periplasmic superoxide dismutases: SodCI and SodCII. Although both proteins are produced during infection, only SodCI is functional in the macrophage phagosome. We have previously shown that SodCI, relative to SodCII, is both protease resistant and tethered within the periplasm and that either of these properties is sufficient to allow a SodC to protect against phagocytic superoxide. Tethering is defined as remaining cell-associated after osmotic shock or treatment with cationic antimicrobial peptides. Here we show that SodCI non-covalently binds peptidoglycan. SodCI binds to Salmonella and Bacillus peptidoglycan, but not peptidoglycan from Staphylococcus. Moreover, binding can be inhibited by a diaminopimelic acid containing tripeptide, but not a lysine containing tripeptide, showing that the protein recognizes the peptide portion of the peptidoglycan. Replacing nine amino acids in SodCII with the corresponding residues from SodCI confers tethering, partially delineating an apparently novel peptidoglycan binding domain. These changes in sequence increase the affinity of SodCII for peptidoglycan fragments to match that of SodCI and allow the now tethered SodCII to function during infection.
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Affiliation(s)
- Avital Tidhar
- Department of Microbiology, University of Illinois at Urbana-Champaign, Ness-Ziona, Israel.,Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Marcus D Rushing
- Department of Microbiology, University of Illinois at Urbana-Champaign, Ness-Ziona, Israel
| | - Byoungkwan Kim
- Department of Microbiology, University of Illinois at Urbana-Champaign, Ness-Ziona, Israel
| | - James M Slauch
- Department of Microbiology, University of Illinois at Urbana-Champaign, Ness-Ziona, Israel.,College of Medicine, University of Illinois at Urbana-Champaign, Ness-Ziona, Israel
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Brennan RE, Kiss K, Baalman R, Samuel JE. Cloning, expression, and characterization of a Coxiella burnetii Cu/Zn Superoxide dismutase. BMC Microbiol 2015; 15:99. [PMID: 25962997 PMCID: PMC4427992 DOI: 10.1186/s12866-015-0430-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 04/23/2015] [Indexed: 11/29/2022] Open
Abstract
Background Periplasmically localized copper-zinc co-factored superoxide dismutase (SodC) enzymes have been identified in a wide range of Gram-negative bacteria and are proposed to protect bacteria from exogenously produced toxic oxygen radicals, which indicates the potential significance of a Coxiella burnetii SodC. Results Assays for SOD activity demonstrated that the cloned C. burnetii insert codes for a SOD that was active over a wide range of pH and inhibitable with 5 mM H2O2 and 1 mM sodium diethyldithiocarbamate, a characteristic of Cu/ZnSODs that distinguishes them from Fe or Mn SODs. The sodC was expressed by C. burnetii, has a molecular weight of approximately 18 kDa, which is consistent with the predicted molecular weight, and localized towards the periphery of C. burnetii. Over expression of the C. burnetii sodC in an E. coli sodC mutant restored resistance to H2O2 killing to wild type levels. Conclusions We have demonstrated that C. burnetii does express a Cu/ZnSOD that is functional at low pH, appears to be excreted, and was able to restore H2O2 resistance in an E. coli sodC mutant. Taken together, these results indicate that the C. burnetii Cu/ZnSOD is a potentially important virulence factor.
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Affiliation(s)
- Robert E Brennan
- Department of Biology, University of Central Oklahoma, 100 North University Drive, Edmond, OK, USA.
| | - Katalin Kiss
- American Type Culture Collection, Manassas, VA, USA.
| | - Rachael Baalman
- Department of Biology, University of Central Oklahoma, 100 North University Drive, Edmond, OK, USA.
| | - James E Samuel
- Department of Medical Microbiology and Immunology, Texas A & M University System Health Science Center, College Station, TX, USA.
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Kurth D, Belfiore C, Gorriti MF, Cortez N, Farias ME, Albarracín VH. Genomic and proteomic evidences unravel the UV-resistome of the poly-extremophile Acinetobacter sp. Ver3. Front Microbiol 2015; 6:328. [PMID: 25954258 PMCID: PMC4406064 DOI: 10.3389/fmicb.2015.00328] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/01/2015] [Indexed: 12/20/2022] Open
Abstract
Ultraviolet radiation can damage biomolecules, with detrimental or even lethal effects for life. Even though lower wavelengths are filtered by the ozone layer, a significant amount of harmful UV-B and UV-A radiation reach Earth's surface, particularly in high altitude environments. high-altitude Andean lakes (HAALs) are a group of disperse shallow lakes and salterns, located at the Dry Central Andes region in South America at altitudes above 3,000 m. As it is considered one of the highest UV-exposed environments, HAAL microbes constitute model systems to study UV-resistance mechanisms in environmental bacteria at various complexity levels. Herein, we present the genome sequence of Acinetobacter sp. Ver3, a gammaproteobacterium isolated from Lake Verde (4,400 m), together with further experimental evidence supporting the phenomenological observations regarding this bacterium ability to cope with increased UV-induced DNA damage. Comparison with the genomes of other Acinetobacter strains highlighted a number of unique genes, such as a novel cryptochrome. Proteomic profiling of UV-exposed cells identified up-regulated proteins such as a specific cytoplasmic catalase, a putative regulator, and proteins associated to amino acid and protein synthesis. Down-regulated proteins were related to several energy-generating pathways such as glycolysis, beta-oxidation of fatty acids, and electronic respiratory chain. To the best of our knowledge, this is the first report on a genome from a polyextremophilic Acinetobacter strain. From the genomic and proteomic data, an "UV-resistome" was defined, encompassing the genes that would support the outstanding UV-resistance of this strain.
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Affiliation(s)
- Daniel Kurth
- Laboratorio de Investigaciones Microbiologicas Lagunas Andinas, Centro Científico Tecnológico, Planta Piloto de Procesos Industriales Microbiológicos - Consejo Nacional de Investigaciones Científicas y Técnicas, San Miguel de Tucumán Argentina
| | - Carolina Belfiore
- Laboratorio de Investigaciones Microbiologicas Lagunas Andinas, Centro Científico Tecnológico, Planta Piloto de Procesos Industriales Microbiológicos - Consejo Nacional de Investigaciones Científicas y Técnicas, San Miguel de Tucumán Argentina
| | - Marta F Gorriti
- Laboratorio de Investigaciones Microbiologicas Lagunas Andinas, Centro Científico Tecnológico, Planta Piloto de Procesos Industriales Microbiológicos - Consejo Nacional de Investigaciones Científicas y Técnicas, San Miguel de Tucumán Argentina
| | - Néstor Cortez
- Centro Científico Tecnológico, IBR - CONICET, Universidad Nacional de Rosario Rosario, Argentina
| | - María E Farias
- Laboratorio de Investigaciones Microbiologicas Lagunas Andinas, Centro Científico Tecnológico, Planta Piloto de Procesos Industriales Microbiológicos - Consejo Nacional de Investigaciones Científicas y Técnicas, San Miguel de Tucumán Argentina
| | - Virginia H Albarracín
- Laboratorio de Investigaciones Microbiologicas Lagunas Andinas, Centro Científico Tecnológico, Planta Piloto de Procesos Industriales Microbiológicos - Consejo Nacional de Investigaciones Científicas y Técnicas, San Miguel de Tucumán Argentina ; Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, San Miguel de Tucumán Argentina
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Henningham A, Döhrmann S, Nizet V, Cole JN. Mechanisms of group A Streptococcus resistance to reactive oxygen species. FEMS Microbiol Rev 2015; 39:488-508. [PMID: 25670736 PMCID: PMC4487405 DOI: 10.1093/femsre/fuu009] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 12/19/2014] [Indexed: 12/16/2022] Open
Abstract
Streptococcus pyogenes, also known as group A Streptococcus (GAS), is an exclusively human Gram-positive bacterial pathogen ranked among the ‘top 10’ causes of infection-related deaths worldwide. GAS commonly causes benign and self-limiting epithelial infections (pharyngitis and impetigo), and less frequent severe invasive diseases (bacteremia, toxic shock syndrome and necrotizing fasciitis). Annually, GAS causes 700 million infections, including 1.8 million invasive infections with a mortality rate of 25%. In order to establish an infection, GAS must counteract the oxidative stress conditions generated by the release of reactive oxygen species (ROS) at the infection site by host immune cells such as neutrophils and monocytes. ROS are the highly reactive and toxic byproducts of oxygen metabolism, including hydrogen peroxide (H2O2), superoxide anion (O2•−), hydroxyl radicals (OH•) and singlet oxygen (O2*), which can damage bacterial nucleic acids, proteins and cell membranes. This review summarizes the enzymatic and regulatory mechanisms utilized by GAS to thwart ROS and survive under conditions of oxidative stress. This review discusses the mechanisms utilized by the bacterial pathogen group A Streptococcus to detoxify reactive oxygen species and survive in the human host under conditions of oxidative stress.
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Affiliation(s)
- Anna Henningham
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA The School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia The Australian Infectious Diseases Research Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Simon Döhrmann
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA
| | - Victor Nizet
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA Rady Children's Hospital, San Diego, CA 92123, USA
| | - Jason N Cole
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA The School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia The Australian Infectious Diseases Research Centre, The University of Queensland, St Lucia, QLD 4072, Australia
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Kasai K, Hashiguchi K, Takahashi H, Kasai A, Takeda S, Nakano M, Ishikawa T, Nakamura T, Miura T. Recombinant production and evaluation of an antibacterial L-amino acid oxidase derived from flounder Platichthys stellatus. Appl Microbiol Biotechnol 2015; 99:6693-703. [PMID: 25661816 DOI: 10.1007/s00253-015-6428-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 01/13/2015] [Accepted: 01/20/2015] [Indexed: 01/20/2023]
Abstract
Fish produce mucus substances as a defensive outer barrier against several bacterial infections. We have recently identified an antibacterial L-amino acid oxidase (psLAAO1) in the mucus layer of the flounder Platichthys stellate. In this study, the antibacterial protein psLAAO1 was expressed as a secretory bioactive recombinant protein in the methylotrophic yeast Pichia pastoris. The recombinant psLAAO1 inhibited the growth of bacteria to the same levels as native psLAAO1 present in mucus. In particular, Staphylococci and Yersinia were strongly suppressed, showing the highest growth retardation of the 21 species and strains tested. Moreover, Staphylococcus epidermidis was most sensitive to psLAAO1 with a minimum inhibitory concentration (MIC) of 0.078 μg/mL, whereas Escherichia coli was essentially resistant to psLAAO1 with a MIC of >10 μg/mL. Interestingly, psLAAO1-treated E. coli were found to upregulate the expression of the btuE gene, which encodes glutathione peroxidase (GPx). The biochemical function of GPx is to reduce free hydrogen peroxide and is induced under response to reactive oxygen species (ROS). Thus, E. coli confers resistance to the reduced free hydrogen peroxide produced by psLAAO1 by increasing GPx levels. Furthermore, the growth of Staphylococcus aureus was completely inhibited in the presence of recombinant psLAAO1. The morphology of psLAAO1-treated S. aureus showed cell surface damage, the formation of large aggregates and the cells showed severe deformations. Western blot analysis showed that psLAAO1 binds to the surface of S. aureus. Therefore, psLAAO1 binds to the surface of LAAO-sensitive S. aureus and directs peroxidative activity at the surface of the bacterial membrane.
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Affiliation(s)
- Kosuke Kasai
- Department of Pathologic Analysis, Division of Medical Life Sciences, Graduate School of Health Sciences, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, Japan
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Abstract
Aldehydes are a class of chemicals with many industrial uses. Several aldehydes are responsible for flavors and fragrances present in plants, but aldehydes are not known to accumulate in most natural microorganisms. In many cases, microbial production of aldehydes presents an attractive alternative to extraction from plants or chemical synthesis. During the past 2 decades, a variety of aldehyde biosynthetic enzymes have undergone detailed characterization. Although metabolic pathways that result in alcohol synthesis via aldehyde intermediates were long known, only recent investigations in model microbes such as Escherichia coli have succeeded in minimizing the rapid endogenous conversion of aldehydes into their corresponding alcohols. Such efforts have provided a foundation for microbial aldehyde synthesis and broader utilization of aldehydes as intermediates for other synthetically challenging biochemical classes. However, aldehyde toxicity imposes a practical limit on achievable aldehyde titers and remains an issue of academic and commercial interest. In this minireview, we summarize published efforts of microbial engineering for aldehyde synthesis, with an emphasis on de novo synthesis, engineered aldehyde accumulation in E. coli, and the challenge of aldehyde toxicity.
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Urano H, Umezawa Y, Yamamoto K, Ishihama A, Ogasawara H. Cooperative regulation of the common target genes between H₂O₂-sensing YedVW and Cu²⁺-sensing CusSR in Escherichia coli. MICROBIOLOGY-SGM 2015; 161:729-38. [PMID: 25568260 DOI: 10.1099/mic.0.000026] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 01/01/2015] [Indexed: 11/18/2022]
Abstract
YedVW is one of the uncharacterized two-component systems (TCSs) of Escherichia coli. In order to identify the regulation targets of YedVW, we performed genomic SELEX (systematic evolution of ligands by exponential enrichment) screening using phosphorylated YedW and an E. coli DNA library, and identified YedW-binding sites within three intergenic spacers, yedW-hiuH, cyoA-ampG and cusR-cusC, along the E. coli genome. Using a reporter assay system, we found that transcription of hiuH, encoding 5-hydroxyisourate hydrolase, was induced at high concentrations of either Cu(2+) or H₂O₂. Cu(2+)-dependent expression of hiuH was observed in the yedWV knockout mutant, but was reduced markedly in the cusRS-null mutant. However, H₂O₂-induced hiuH expression was observed in the cusRS-null mutant, but not in the yedWV-null mutant. Gel mobility shift and DNase I footprinting analyses showed binding of both YedW and CusR to essentially the same sequence within the hiuH promoter region. Taken together, we concluded that YedVW and CusSR formed a unique cooperative TCS pair by recognizing and regulating the same targets, but under different environmental conditions - YedVW played a role in H₂O₂ response regulation, whilst CusSR played a role in Cu(2+) response regulation.
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Affiliation(s)
- Hiroyuki Urano
- Research Center for Human and Environmental Sciences, Shinshu University, Ueda, Nagano 386-8567, Japan
| | - Yoshimasa Umezawa
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 184-8584, Japan
| | - Kaneyoshi Yamamoto
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 184-8584, Japan Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-8584, Japan
| | - Akira Ishihama
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 184-8584, Japan Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-8584, Japan
| | - Hiroshi Ogasawara
- Research Center for Human and Environmental Sciences, Shinshu University, Ueda, Nagano 386-8567, Japan
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Baez A, Shiloach J. Effect of elevated oxygen concentration on bacteria, yeasts, and cells propagated for production of biological compounds. Microb Cell Fact 2014; 13:181. [PMID: 25547171 PMCID: PMC4279996 DOI: 10.1186/s12934-014-0181-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 12/11/2014] [Indexed: 12/03/2022] Open
Abstract
The response of bacteria, yeast, and mammalian and insects cells to oxidative stress is a topic that has been studied for many years. However, in most the reported studies, the oxidative stress was caused by challenging the organisms with H2O2 and redox-cycling drugs, but not by subjecting the cells to high concentrations of molecular oxygen. In this review we summarize available information about the effect of elevated oxygen concentrations on the physiology of microorganisms and cells at various culture conditions. In general, increased oxygen concentrations promote higher leakage of reactive oxygen species (superoxide and H2O2) from the respiratory chain affecting metalloenzymes and DNA that in turn cause impaired growth and elevated mutagenesis. To prevent the potential damage, the microorganisms and cells respond by activating antioxidant defenses and repair systems. This review described the factors that affect growth properties and metabolism at elevated oxygen concentrations that cells may be exposed to, in bioreactor sparged with oxygen enriched air which could affect the yield and quality of the recombinant proteins produced by high cell density schemes.
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Affiliation(s)
| | - Joseph Shiloach
- Biotechnology Core Laboratory, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda 20892, MD, USA.
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Burbank L, Roper MC. OxyR and SoxR modulate the inducible oxidative stress response and are implicated during different stages of infection for the bacterial phytopathogen Pantoea stewartii subsp. stewartii. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:479-490. [PMID: 24450773 DOI: 10.1094/mpmi-11-13-0348-r] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Reactive oxygen species (ROS) from a variety of sources are often encountered by invading plant pathogens during the infection process. Pantoea stewartii subsp. stewartii, the etiological agent of Stewart's wilt, is a serious bacterial pathogen of sweet corn that colonizes both the apoplast and xylem tissues in which ROS are produced. The P. stewartii genome predicts the presence of two redox-sensing transcriptional regulators, OxyR and SoxR, which both activate gene expression in response to oxidative stress. ROS exposure in the form of hydrogen peroxide and the superoxide-generating compound paraquat initiates an induced stress response through OxyR and SoxR that includes activation of the ROS-detoxifying enzymes alkyl hydroperoxide reductase and superoxide dismutase. P. stewartii ΔsoxR was more sensitive to paraquat and was compromised in the ability to form water-soaked lesions, while ΔoxyR was more sensitive to hydrogen peroxide treatment and was deficient in exopolysaccharide production and the elicitation of wilting symptoms. This demonstrates that both SoxR and OxyR play an important role in virulence in the different niches that P. stewartii colonize during the infection process.
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Rakleova G, Pouneva I, Dobrev N, Tchorbadjieva M. Differentially Secreted Proteins of Antarctic and Mesophilic Strains ofSynechocystis SalinaandChlorella Vulgarisafter UV-B and Temperature Stress Treatment. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.5504/bbeq.2013.0002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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