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Ciemniecki JA, Newman DK. The Potential for Redox-Active Metabolites To Enhance or Unlock Anaerobic Survival Metabolisms in Aerobes. J Bacteriol 2020; 202:e00797-19. [PMID: 32071098 PMCID: PMC7221258 DOI: 10.1128/jb.00797-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Classifying microorganisms as "obligate" aerobes has colloquially implied death without air, leading to the erroneous assumption that, without oxygen, they are unable to survive. However, over the past few decades, more than a few obligate aerobes have been found to possess anaerobic energy conservation strategies that sustain metabolic activity in the absence of growth or at very low growth rates. Similarly, studies emphasizing the aerobic prowess of certain facultative aerobes have sometimes led to underrecognition of their anaerobic capabilities. Yet an inescapable consequence of the affinity both obligate and facultative aerobes have for oxygen is that the metabolism of these organisms may drive this substrate to scarcity, making anoxic survival an essential skill. To illustrate this, we highlight the importance of anaerobic survival strategies for Pseudomonas aeruginosa and Streptomyces coelicolor, representative facultative and obligate aerobes, respectively. Included among these strategies, we describe a role for redox-active secondary metabolites (RAMs), such as phenazines made by P. aeruginosa, in enhancing substrate-level phosphorylation. Importantly, RAMs are made by diverse bacteria, often during stationary phase in the absence of oxygen, and can sustain anoxic survival. We present a hypothesis for how RAMs may enhance or even unlock energy conservation pathways that facilitate the anaerobic survival of both RAM producers and nonproducers.
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Affiliation(s)
- John A Ciemniecki
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Dianne K Newman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA
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52
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Chen Z, Li Z, Li F, Wang N, Gao XD. Characterization of alditol oxidase from Streptomyces coelicolor and its application in the production of rare sugars. Bioorg Med Chem 2020; 28:115464. [DOI: 10.1016/j.bmc.2020.115464] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 02/21/2020] [Accepted: 03/23/2020] [Indexed: 01/06/2023]
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53
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Mosteo R, Varon Lopez A, Muzard D, Benitez N, Giannakis S, Pulgarin C. Visible light plays a significant role during bacterial inactivation by the photo-fenton process, even at sub-critical light intensities. WATER RESEARCH 2020; 174:115636. [PMID: 32109753 DOI: 10.1016/j.watres.2020.115636] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/15/2020] [Accepted: 02/18/2020] [Indexed: 06/10/2023]
Abstract
The aim of this research is to clarify the contribution of sunlight wavelengths, irradiance and Fe2+/H2O2 during bacterial disinfection by the photo-Fenton process in clear surface waters. We considered different solar spectrum distributions (visible, UVA-Visible), sub-critical irradiances (0-400 W/m2), focusing on the action modes of E. coli inactivation by the constituents involved in the composite process, at low μM reactants concentration (Fe2+/H2O2) in in ultrapure (MQ) water. We report that solar disinfection improved with Fenton reagents (photo-Fenton process) is a reality from very low light irradiance values (200 W/m2), and made possible even without the presence of UVA radiation, even when using low quantities of the Fenton reagents (0.5 mg/L Fe2+, 5 mg/L H2O2). Under light exposure, H2O2 was found to augment the intracellular Fenton process and Fe2+ to initiate further, distinct oxidative actions. Finally, validation was performed in Lake Geneva water over a wider irradiance range, where the photo-Fenton process was found to be reagent-dependent in low irradiance, shifting to light-driven in the higher values.
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Affiliation(s)
- Rosa Mosteo
- Department of Chemical Engineering and Environmental Technology, Environmental Sciences Institute (IUCA), University of Zaragoza, Zaragoza, Spain; School of Basic Sciences (SB), Institute of Chemical Science and Engineering (ISIC), Group of Advanced Oxidation Processes (GPAO), École Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015, Lausanne, Switzerland
| | - Angelica Varon Lopez
- School of Basic Sciences (SB), Institute of Chemical Science and Engineering (ISIC), Group of Advanced Oxidation Processes (GPAO), École Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015, Lausanne, Switzerland; Universidad del Valle, Departamento de Química, Grupo de Investigación en Procesos Avanzados de Oxidación (GAOX), A.A. 25360 Cali, Colombia
| | - David Muzard
- School of Basic Sciences (SB), Institute of Chemical Science and Engineering (ISIC), Group of Advanced Oxidation Processes (GPAO), École Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015, Lausanne, Switzerland
| | - Norberto Benitez
- Universidad del Valle, Departamento de Química, Grupo de Investigación en Procesos Avanzados de Oxidación (GAOX), A.A. 25360 Cali, Colombia
| | - Stefanos Giannakis
- Universidad Politécnica de Madrid (UPM), E.T.S. Ingenieros de Caminos, Canales y Puertos, Departamento de Ingeniería Civil: Hidráulica, Energía y Medio Ambiente, Unidad docente Ingeniería Sanitaria, c/ Profesor Aranguren, s/n, ES-28040, Madrid, Spain.
| | - Cesar Pulgarin
- School of Basic Sciences (SB), Institute of Chemical Science and Engineering (ISIC), Group of Advanced Oxidation Processes (GPAO), École Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015, Lausanne, Switzerland.
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Nicol MJ, Brubaker TR, Honish BJ, Simmons AN, Kazemi A, Geissel MA, Whalen CT, Siedlecki CA, Bilén SG, Knecht SD, Kirimanjeswara GS. Antibacterial effects of low-temperature plasma generated by atmospheric-pressure plasma jet are mediated by reactive oxygen species. Sci Rep 2020; 10:3066. [PMID: 32080228 PMCID: PMC7033188 DOI: 10.1038/s41598-020-59652-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 12/13/2019] [Indexed: 12/05/2022] Open
Abstract
Emergence and spread of antibiotic resistance calls for development of non-chemical treatment options for bacterial infections. Plasma medicine applies low-temperature plasma (LTP) physics to address biomedical problems such as wound healing and tumor suppression. LTP has also been used for surface disinfection. However, there is still much to be learned regarding the effectiveness of LTP on bacteria in suspension in liquids, and especially on porous surfaces. We investigated the efficacy of LTP treatments against bacteria using an atmospheric-pressure plasma jet and show that LTP treatments have the ability to inhibit both gram-positive (S. aureus) and gram-negative (E. coli) bacteria on solid and porous surfaces. Additionally, both direct LTP treatment and plasma-activated media were effective against the bacteria suspended in liquid culture. Our data indicate that reactive oxygen species are the key mediators of the bactericidal effects of LTP and hydrogen peroxide is necessary but not sufficient for antibacterial effects. In addition, our data suggests that bacteria exposed to LTP do not develop resistance to further treatment with LTP. These findings suggest that this novel atmospheric-pressure plasma jet could be used as a potential alternative to antibiotic treatments in vivo.
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Affiliation(s)
- McKayla J Nicol
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
- Pathobiology Graduate Program, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Timothy R Brubaker
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Brian J Honish
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Alyssa N Simmons
- Department of Mechanical Engineering and Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Ali Kazemi
- Department of Mechanical Engineering and Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Madison A Geissel
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Connor T Whalen
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | | | - Sven G Bilén
- School of Engineering Design, Technology, and Professional Programs, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Sean D Knecht
- School of Engineering Design, Technology, and Professional Programs, The Pennsylvania State University, University Park, PA, 16802, USA.
| | - Girish S Kirimanjeswara
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, 16802, USA.
- The Center for Molecular Immunology and Infectious Disease, The Pennsylvania State University, University Park, PA, 16802, USA.
- The Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, 16802, USA.
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55
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Kashyap DR, Kowalczyk DA, Shan Y, Yang CK, Gupta D, Dziarski R. Formate dehydrogenase, ubiquinone, and cytochrome bd-I are required for peptidoglycan recognition protein-induced oxidative stress and killing in Escherichia coli. Sci Rep 2020; 10:1993. [PMID: 32029761 PMCID: PMC7005000 DOI: 10.1038/s41598-020-58302-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 01/14/2020] [Indexed: 11/09/2022] Open
Abstract
Mammalian Peptidoglycan Recognition Proteins (PGRPs) kill bacteria through induction of synergistic oxidative, thiol, and metal stress. PGRPs induce oxidative stress in bacteria through a block in the respiratory chain, which results in decreased respiration and incomplete reduction of oxygen (O2) to hydrogen peroxide (H2O2). In this study we identify the site of PGRP-induced generation of H2O2 in Escherichia coli. Tn-seq screening of E. coli Tn10 insertion library revealed that mutants in formate dehydrogenase (FDH) genes had the highest survival following PGRP treatment. Mutants lacking functional FDH-O had abolished PGRP-induced H2O2 production and the highest resistance to PGRP-induced killing, and formate enhanced PGRP-induced killing and H2O2 production in an FDH-dependent manner. Mutants in ubiquinone synthesis (but not menaquinone and demethylmenaquinone) and cytochrome bd-I (but not cytochromes bo3 and bd-II) also had completely abolished PGRP-induced H2O2 production and high resistance to PGRP-induced killing. Because electrons in the respiratory chain flow from dehydrogenases' substrates through quinones and then cytochromes to O2, these results imply that the site of PGRP-induced incomplete reduction of O2 to H2O2 is downstream from dehydrogenases and ubiquinone at the level of cytochrome bd-I, which results in oxidative stress. These results reveal several essential steps in PGRP-induced bacterial killing.
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Affiliation(s)
- Des R Kashyap
- Indiana University School of Medicine-Northwest, Gary, IN, 46408, USA
| | | | - Yue Shan
- Antimicrobial Discovery Center, Northeastern University, Boston, MA, 02115, USA.,Department of Medicine, The University of Chicago, Chicago, 60637, USA
| | - Chun-Kai Yang
- Indiana University School of Medicine-Northwest, Gary, IN, 46408, USA
| | - Dipika Gupta
- Indiana University School of Medicine-Northwest, Gary, IN, 46408, USA
| | - Roman Dziarski
- Indiana University School of Medicine-Northwest, Gary, IN, 46408, USA.
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56
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Akhova AV, Sekatskaya PA, Tkachenko AG. Formation of Associated Oxidative Stress in Cells of Escherichia coli Exposed to Different Environmental Stressors. APPL BIOCHEM MICRO+ 2019. [DOI: 10.1134/s0003683819060036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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57
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Mascolo L, Bald D. Cytochrome bd in Mycobacterium tuberculosis: A respiratory chain protein involved in the defense against antibacterials. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 152:55-63. [PMID: 31738981 DOI: 10.1016/j.pbiomolbio.2019.11.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/12/2019] [Indexed: 12/27/2022]
Abstract
The branched respiratory chain of Mycobacterium tuberculosis has attracted attention as a highly promising target for next-generation antibacterials. This system includes two terminal oxidases of which the exclusively bacterial cytochrome bd represents the less energy-efficient one. Albeit dispensable for growth under standard laboratory conditions, cytochrome bd is important during environmental stress. In this review, we discuss the role of cytochrome bd during infection of the mammalian host and in the defense against antibacterials. Deeper insight into the biochemistry of mycobacterial cytochrome bd is needed to understand the physiological role of this bacteria-specific defense factor. Conversely, cytochrome bd may be utilized to gain information on mycobacterial physiology in vitro and during host infection. Knowledge-based manipulation of cytochrome bd function may assist in designing the next-generation tuberculosis combination chemotherapy.
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Affiliation(s)
- Ludovica Mascolo
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Dirk Bald
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands.
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58
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Nair RR, Sharan D, Ajitkumar P. A Minor Subpopulation of Mycobacteria Inherently Produces High Levels of Reactive Oxygen Species That Generate Antibiotic Resisters at High Frequency From Itself and Enhance Resister Generation From Its Major Kin Subpopulation. Front Microbiol 2019; 10:1842. [PMID: 31456773 PMCID: PMC6700507 DOI: 10.3389/fmicb.2019.01842] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/26/2019] [Indexed: 12/17/2022] Open
Abstract
Antibiotic-exposed bacteria produce elevated levels of reactive oxygen species (ROS), to which either they succumb or get mutated genome-wide to generate antibiotic resisters. We recently showed that mycobacterial cultures contained two subpopulations, short-sized cells (SCs; ∼10%) and normal/long-sized cells (NCs; ∼90%). The SCs were significantly more antibiotic-susceptible than the NCs. It implied that the SCs might naturally be predisposed to generate significantly higher levels of ROS than the NCs. This in turn could make the SCs more susceptible to antibiotics or generate more resisters as compared to the NCs. Investigation into this possibility showed that the SCs in the actively growing mid-log phase culture naturally generated significantly high levels of superoxide, as compared to the equivalent NCs, due to the naturally high expression of a specific NADH oxidase in the SCs. This caused labile Fe2+ leaching from 4Fe-4S proteins and elevated H2O2 formation through superoxide dismutation. Thus, the SCs of both Mycobacterium smegmatis and Mycobacterium tuberculosis inherently contained significantly higher levels of H2O2 and labile Fe2+ than the NCs. This in turn produced significantly higher levels of hydroxyl radical through Fenton reaction, promoting enhanced antibiotic resister generation from the SCs than from the NCs. The SCs, when mixed back with the NCs, at their natural proportion in the actively growing mid-log phase culture, enhanced antibiotic resister generation from the NCs, to a level equivalent to that from the unfractionated whole culture. The enhanced antibiotic resister generation from the NCs in the reconstituted SCs-NCs natural mixture was found to be due to the high levels of H2O2 secreted by the SCs. Thus, the present work unveils and documents the metabolic designs of two mycobacterial subpopulations where one subpopulation produces high ROS levels, despite higher susceptibility, to generate significantly higher number of antibiotic resisters from itself and to enhance resister generation from its kin subpopulation. These findings show the existence of an inherent natural mechanism in both the non-pathogenic and pathogenic mycobacteria to generate antibiotic resisters. The presence of the SCs and the NCs in the pulmonary tuberculosis patients’ sputum, reported by us earlier, alludes to the clinical significance of the study.
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Affiliation(s)
- Rashmi Ravindran Nair
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Deepti Sharan
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
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59
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Shaeer A, Aslam M, Rashid N. A highly stable manganese catalase from Geobacillus thermopakistaniensis: molecular cloning and characterization. Extremophiles 2019; 23:707-718. [DOI: 10.1007/s00792-019-01124-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 07/26/2019] [Indexed: 01/08/2023]
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60
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Pena RT, Blasco L, Ambroa A, González-Pedrajo B, Fernández-García L, López M, Bleriot I, Bou G, García-Contreras R, Wood TK, Tomás M. Relationship Between Quorum Sensing and Secretion Systems. Front Microbiol 2019; 10:1100. [PMID: 31231316 PMCID: PMC6567927 DOI: 10.3389/fmicb.2019.01100] [Citation(s) in RCA: 146] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 04/30/2019] [Indexed: 01/15/2023] Open
Abstract
Quorum sensing (QS) is a communication mechanism between bacteria that allows specific processes to be controlled, such as biofilm formation, virulence factor expression, production of secondary metabolites and stress adaptation mechanisms such as bacterial competition systems including secretion systems (SS). These SS have an important role in bacterial communication. SS are ubiquitous; they are present in both Gram-negative and Gram-positive bacteria and in Mycobacterium sp. To date, 8 types of SS have been described (T1SS, T2SS, T3SS, T4SS, T5SS, T6SS, T7SS, and T9SS). They have global functions such as the transport of proteases, lipases, adhesins, heme-binding proteins, and amidases, and specific functions such as the synthesis of proteins in host cells, adaptation to the environment, the secretion of effectors to establish an infectious niche, transfer, absorption and release of DNA, translocation of effector proteins or DNA and autotransporter secretion. All of these functions can contribute to virulence and pathogenesis. In this review, we describe the known types of SS and discuss the ones that have been shown to be regulated by QS. Due to the large amount of information about this topic in some pathogens, we focus mainly on Pseudomonas aeruginosa and Vibrio spp.
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Affiliation(s)
- Rocio Trastoy Pena
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Lucia Blasco
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Antón Ambroa
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Bertha González-Pedrajo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Laura Fernández-García
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Maria López
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Ines Bleriot
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - German Bou
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Rodolfo García-Contreras
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Thomas Keith Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, United States
| | - Maria Tomás
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
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Nair RR, Sharan D, Sebastian J, Swaminath S, Ajitkumar P. Heterogeneity of ROS levels in antibiotic-exposed mycobacterial subpopulations confers differential susceptibility. MICROBIOLOGY-SGM 2019; 165:668-682. [PMID: 31091187 DOI: 10.1099/mic.0.000797] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Phenotypically heterogeneous but genetically identical mycobacterial subpopulations exist in in vitro cultures, in vitro-infected macrophages, infected animal models and tuberculosis patients. In this regard, we recently reported the presence of two subpopulations of cells, which are phenotypically different in length and buoyant density, in mycobacterial cultures. These are the low-buoyant-density short-sized cells (SCs), which constitute ~10-20 % of the population, and the high-buoyant-density normal/long-sized cells (NCs), which form ~80-90 % of the population. The SCs were found to be significantly more susceptible to rifampicin (RIF), isoniazid (INH), H2O2 and acidified nitrite than the NCs. Here we report that the RIF-/INH-/H2O2-exposed SCs showed significantly higher levels of oxidative stress and therefore higher susceptibility than the equivalent number of exposed NCs. Significantly higher levels of hydroxyl radical and superoxide were found in the antibiotic-exposed SCs than in the equivalently exposed NCs. Different proportions of the subpopulation of SCs were found to have different levels of reactive oxygen species (ROS). The hydroxyl radical quencher, thiourea, and the superoxide dismutase mimic, TEMPOL, significantly reduced hydroxyl radical and superoxide levels, respectively, in the antibiotic-exposed SCs and NCs and thereby decreased their differential susceptibility to antibiotics. Thus, the present study shows that the heterogeneity of the reactive oxygen species (ROS) levels in these mycobacterial subpopulations confers differential susceptibility to antibiotics. We have discussed the possible mechanisms that can generate differential ROS levels in the antibiotic-exposed SCs and NCs. The present study advances our current understanding of the molecular mechanisms underlying antibiotic tolerance in mycobacteria.
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Affiliation(s)
- Rashmi Ravindran Nair
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore - 560012, Karnataka, India
| | - Deepti Sharan
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore - 560012, Karnataka, India
| | - Jees Sebastian
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore - 560012, Karnataka, India
| | - Sharmada Swaminath
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore - 560012, Karnataka, India
| | - Parthasarathi Ajitkumar
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore - 560012, Karnataka, India
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62
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Zerfaß C, Christie-Oleza JA, Soyer OS. Manganese Oxide Biomineralization Provides Protection against Nitrite Toxicity in a Cell-Density-Dependent Manner. Appl Environ Microbiol 2019; 85:e02129-18. [PMID: 30413475 PMCID: PMC6328764 DOI: 10.1128/aem.02129-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/01/2018] [Indexed: 12/12/2022] Open
Abstract
Manganese biomineralization is a widespread process among bacteria and fungi. To date, there is no conclusive experimental evidence for how and if this process impacts microbial fitness in the environment. Here, we show how a model organism for manganese oxidation is growth inhibited by nitrite, and that this inhibition is mitigated in the presence of manganese. We show that such manganese-mediated mitigation of nitrite inhibition is dependent on the culture inoculum size, and that manganese oxide (MnOX) forms granular precipitates in the culture, rather than sheaths around individual cells. We provide evidence that MnOX protection involves both its ability to catalyze nitrite oxidation into (nontoxic) nitrate under physiological conditions and its potential role in influencing processes involving reactive oxygen species (ROS). Taken together, these results demonstrate improved microbial fitness through MnOX deposition in an ecological setting, i.e., mitigation of nitrite toxicity, and point to a key role of MnOX in handling stresses arising from ROS.IMPORTANCE We present here a direct fitness benefit (i.e., growth advantage) for manganese oxide biomineralization activity in Roseobacter sp. strain AzwK-3b, a model organism used to study this process. We find that strain AzwK-3b in a laboratory culture experiment is growth inhibited by nitrite in manganese-free cultures, while the inhibition is considerably relieved by manganese supplementation and manganese oxide (MnOX) formation. We show that biogenic MnOX interacts directly with nitrite and possibly with reactive oxygen species and find that its beneficial effects are established through formation of dispersed MnOX granules in a manner dependent on the population size. These experiments raise the possibility that manganese biomineralization could confer protection against nitrite toxicity to a population of cells. They open up new avenues of interrogating this process in other species and provide possible routes to their biotechnological applications, including in metal recovery, biomaterials production, and synthetic community engineering.
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Affiliation(s)
- Christian Zerfaß
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- Warwick Integrative Synthetic Biology Centre (WISB), University of Warwick, Coventry, United Kingdom
| | - Joseph A Christie-Oleza
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- Warwick Integrative Synthetic Biology Centre (WISB), University of Warwick, Coventry, United Kingdom
| | - Orkun S Soyer
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- Warwick Integrative Synthetic Biology Centre (WISB), University of Warwick, Coventry, United Kingdom
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63
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Imlay JA. Where in the world do bacteria experience oxidative stress? Environ Microbiol 2018; 21:521-530. [PMID: 30307099 DOI: 10.1111/1462-2920.14445] [Citation(s) in RCA: 174] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/02/2018] [Accepted: 10/07/2018] [Indexed: 11/26/2022]
Abstract
Reactive oxygen species - superoxide, hydrogen peroxide and hydroxyl radicals - have long been suspected of constraining bacterial growth in important microbial habitats and indeed of shaping microbial communities. Over recent decades, studies of paradigmatic organisms such as Escherichia coli, Salmonella typhimurium, Bacillus subtilis and Saccharomyces cerevisiae have pinpointed the biomolecules that oxidants can damage and the strategies by which microbes minimize their injuries. What is lacking is a good sense of the circumstances under which oxidative stress actually occurs. In this MiniReview several potential natural sources of oxidative stress are considered: endogenous ROS formation, chemical oxidation of reduced species at oxic-anoxic interfaces, H2 O2 production by lactic acid bacteria, the oxidative burst of phagocytes and the redox-cycling of secreted small molecules. While all of these phenomena can be reproduced and verified in the lab, the actual quantification of stress in natural habitats remains lacking - and, therefore, we have a fundamental hole in our understanding of the role that oxidative stress actually plays in the biosphere.
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Affiliation(s)
- James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
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Lv Y, Cheng X, Wu D, Du G, Zhou J, Chen J. Improving bioconversion of eugenol to coniferyl alcohol by in situ eliminating harmful H 2O 2. BIORESOURCE TECHNOLOGY 2018; 267:578-583. [PMID: 30055475 DOI: 10.1016/j.biortech.2018.07.104] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/19/2018] [Accepted: 07/20/2018] [Indexed: 06/08/2023]
Abstract
Coniferyl alcohol is a valuable chemical. However, the current approaches to obtain coniferyl alcohol are either unefficient or expensive. Penicillium simplicissimum vanillyl alcohol oxidase (PsVAO) can be used to produce coniferyl alcohol. However, PsVAO intrinsically produces harmful byproduct H2O2. Utilizing catalase to decompose H2O2 is a potential straightforward approach; however, catalase can also exhibit peroxidase activity to facilitate coniferyl alcohol over-oxidation. In this study, catalases exhibiting both high catalase activity and low peroxidase activity were found out, and introduced into the bioconversion systems. Our results showed that eliminating H2O2in situ released H2O2 inhibition of PsVAO, improved coniferyl alcohol production and eliminated coniferyl alcohol over-oxidation. Finally, coniferyl alcohol titer, molar yield, and productivity reached 22.9 g/L, 78.7%, and 0.5 g/(L × h) respectively. An efficient coniferyl alcohol production method was developed by overcoming the intrinsic disadvantages of PsVAO.
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Affiliation(s)
- Yongkun Lv
- Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Xiaozhong Cheng
- The Key Laboratory of Carbohydrate Chemistry & Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Di Wu
- Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Guocheng Du
- Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; The Key Laboratory of Carbohydrate Chemistry & Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Jingwen Zhou
- Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
| | - Jian Chen
- Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
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Colonization efficiency of Pseudomonas putida is influenced by Fis-controlled transcription of nuoA-N operon. PLoS One 2018; 13:e0201841. [PMID: 30071101 PMCID: PMC6072106 DOI: 10.1371/journal.pone.0201841] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 07/22/2018] [Indexed: 02/07/2023] Open
Abstract
Root colonization of plant growth-promoting bacteria is a complex multistep process that is influenced by several factors. For example, during adherence to plant roots, bacteria have to endure reactive oxygen species (ROS) produced by plants. In this study, we report that the global transcriptional regulator Fis is involved in the regulation of ROS-tolerance of Pseudomonas putida and thereby affects barley root colonization. Fis overexpression reduced both ROS-tolerance and adherence to barley roots and activated the transcription of the nuoA-N operon encoding NADH dehydrogenase I, the first enzyme of a membrane-bound electron-transport chain. The nuoA-N knockout mutation in the fis-overexpression background increased the ROS-tolerance and adherence to barley roots. We show that nuoA has two transcriptional start sites located 104 and 377 nucleotides upstream of the coding sequence, indicating the presence of two promoters. The DNase I footprint analysis revealed four Fis binding sites: Fis-nuo1 to Fis-nuo4, situated between these two promoters. Site-directed mutagenesis in a promoter-lacZ reporter and β-galactosidase assay further confirmed direct binding of Fis to Fis-nuo2 and probably to Fis-nuo4 but not to Fis-nuo1 and Fis-nuo3. Additionally, the results implied that Fis binding to Fis-nuo4 could affect transcription of the nuoA-N operon by modification of upstream DNA topology. Moreover, our transposon mutagenesis results indicated that Fis might be involved in the regulation of several alternative ROS detoxification processes utilizing NADH.
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Mechanisms of Bacterial Tolerance and Persistence in the Gastrointestinal and Respiratory Environments. Clin Microbiol Rev 2018; 31:31/4/e00023-18. [PMID: 30068737 DOI: 10.1128/cmr.00023-18] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Pathogens that infect the gastrointestinal and respiratory tracts are subjected to intense pressure due to the environmental conditions of the surroundings. This pressure has led to the development of mechanisms of bacterial tolerance or persistence which enable microorganisms to survive in these locations. In this review, we analyze the general stress response (RpoS mediated), reactive oxygen species (ROS) tolerance, energy metabolism, drug efflux pumps, SOS response, quorum sensing (QS) bacterial communication, (p)ppGpp signaling, and toxin-antitoxin (TA) systems of pathogens, such as Escherichia coli, Salmonella spp., Vibrio spp., Helicobacter spp., Campylobacter jejuni, Enterococcus spp., Shigella spp., Yersinia spp., and Clostridium difficile, all of which inhabit the gastrointestinal tract. The following respiratory tract pathogens are also considered: Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Burkholderia cenocepacia, and Mycobacterium tuberculosis Knowledge of the molecular mechanisms regulating the bacterial tolerance and persistence phenotypes is essential in the fight against multiresistant pathogens, as it will enable the identification of new targets for developing innovative anti-infective treatments.
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67
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Gugala N, Lemire J, Chatfield-Reed K, Yan Y, Chua G, Turner RJ. Using a Chemical Genetic Screen to Enhance Our Understanding of the Antibacterial Properties of Silver. Genes (Basel) 2018; 9:E344. [PMID: 29986482 PMCID: PMC6071238 DOI: 10.3390/genes9070344] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 06/30/2018] [Accepted: 07/03/2018] [Indexed: 12/26/2022] Open
Abstract
It is essential to understand the mechanisms by which a toxicant is capable of poisoning the bacterial cell. The mechanism of action of many biocides and toxins, including numerous ubiquitous compounds, is not fully understood. For example, despite the widespread clinical and commercial use of silver (Ag), the mechanisms describing how this metal poisons bacterial cells remains incomplete. To advance our understanding surrounding the antimicrobial action of Ag, we performed a chemical genetic screen of a mutant library of Escherichia coli—the Keio collection, in order to identify Ag sensitive or resistant deletion strains. Indeed, our findings corroborate many previously established mechanisms that describe the antibacterial effects of Ag, such as the disruption of iron-sulfur clusters containing proteins and certain cellular redox enzymes. However, the data presented here demonstrates that the activity of Ag within the bacterial cell is more extensive, encompassing genes involved in cell wall maintenance, quinone metabolism and sulfur assimilation. Altogether, this study provides further insight into the antimicrobial mechanism of Ag and the physiological adaption of E. coli to this metal.
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Affiliation(s)
- Natalie Gugala
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
| | - Joe Lemire
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
| | - Kate Chatfield-Reed
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
| | - Ying Yan
- Department of Mathematics and Statistics, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
| | - Gordon Chua
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
| | - Raymond J Turner
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
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Robertson J, Gizdavic-Nikolaidis M, Nieuwoudt MK, Swift S. The antimicrobial action of polyaniline involves production of oxidative stress while functionalisation of polyaniline introduces additional mechanisms. PeerJ 2018; 6:e5135. [PMID: 29967756 PMCID: PMC6026458 DOI: 10.7717/peerj.5135] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 06/08/2018] [Indexed: 12/31/2022] Open
Abstract
Polyaniline (PANI) and functionalised polyanilines (fPANI) are novel antimicrobial agents whose mechanism of action was investigated. Escherichia coli single gene deletion mutants revealed that the antimicrobial mechanism of PANI likely involves production of hydrogen peroxide while homopolymer poly(3-aminobenzoic acid), P3ABA, used as an example of a fPANI, disrupts metabolic and respiratory machinery, by targeting ATP synthase and causes acid stress. PANI was more active against E. coli in aerobic, compared to anaerobic, conditions, while this was apparent for P3ABA only in rich media. Greater activity in aerobic conditions suggests involvement of reactive oxygen species. P3ABA treatment causes an increase in intracellular free iron, which is linked to perturbation of metabolic enzymes and could promote reactive oxygen species production. Addition of exogenous catalase protected E. coli from PANI antimicrobial action; however, this was not apparent for P3ABA treated cells. The results presented suggest that PANI induces production of hydrogen peroxide, which can promote formation of hydroxyl radicals causing biomolecule damage and potentially cell death. P3ABA is thought to act as an uncoupler by targeting ATP synthase resulting in a futile cycle, which precipitates dysregulation of iron homeostasis, oxidative stress, acid stress, and potentially the fatal loss of proton motive force.
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Affiliation(s)
- Julia Robertson
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | | | | | - Simon Swift
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
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The Transcription Factor ZafA Regulates the Homeostatic and Adaptive Response to Zinc Starvation in Aspergillus fumigatus. Genes (Basel) 2018; 9:genes9070318. [PMID: 29949939 PMCID: PMC6070888 DOI: 10.3390/genes9070318] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 06/20/2018] [Accepted: 06/20/2018] [Indexed: 12/20/2022] Open
Abstract
One of the most important features that enables Aspergillus fumigatus to grow within a susceptible individual and to cause disease is its ability to obtain Zn2+ ions from the extremely zinc-limited environment provided by host tissues. Zinc uptake from this source in A. fumigatus relies on ZIP transporters encoded by the zrfA, zrfB and zrfC genes. The expression of these genes is tightly regulated by the ZafA transcription factor that regulates zinc homeostasis and is essential for A. fumigatus virulence. We combined the use of microarrays, Electrophoretic Mobility Shift Assays (EMSA) analyses, DNase I footprinting assays and in silico tools to better understand the regulation of the homeostatic and adaptive response of A. fumigatus to zinc starvation. We found that under zinc-limiting conditions, ZafA functions mainly as a transcriptional activator through binding to a zinc response sequence located in the regulatory regions of its target genes, although it could also function as a repressor of a limited number of genes. In addition to genes involved in the homeostatic response to zinc deficiency, ZafA also influenced, either directly or indirectly, the expression of many other genes. It is remarkable that the expression of many genes involved in iron uptake and ergosterol biosynthesis is strongly reduced under zinc starvation, even though only the expression of some of these genes appeared to be influenced directly or indirectly by ZafA. In addition, it appears to exist in A. fumigatus a zinc/iron cross-homeostatic network to allow the adaptation of the fungus to grow in media containing unbalanced Zn:Fe ratios. The adaptive response to oxidative stress typically linked to zinc starvation was also mediated by ZafA, as was the strong induction of genes involved in gliotoxin biosynthesis and self-protection against endogenous gliotoxin. This study has expanded our knowledge about the regulatory and metabolic changes displayed by A. fumigatus in response to zinc starvation and has helped us to pinpoint new ZafA target genes that could be important for fungal pathogens to survive and grow within host tissues and, hence, for virulence.
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70
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Endogenous superoxide is a key effector of the oxygen sensitivity of a model obligate anaerobe. Proc Natl Acad Sci U S A 2018; 115:E3266-E3275. [PMID: 29559534 DOI: 10.1073/pnas.1800120115] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It has been unclear whether superoxide and/or hydrogen peroxide play important roles in the phenomenon of obligate anaerobiosis. This question was explored using Bacteroides thetaiotaomicron, a major fermentative bacterium in the human gastrointestinal tract. Aeration inactivated two enzyme families-[4Fe-4S] dehydratases and nonredox mononuclear iron enzymes-whose homologs, in contrast, remain active in aerobic Escherichia coli Inactivation-rate measurements of one such enzyme, B. thetaiotaomicron fumarase, showed that it is no more intrinsically sensitive to oxidants than is an E. coli fumarase. Indeed, when the E. coli enzymes were expressed in B. thetaiotaomicron, they no longer could tolerate aeration; conversely, the B. thetaiotaomicron enzymes maintained full activity when expressed in aerobic E. coli Thus, the aerobic inactivation of the B. thetaiotaomicron enzymes is a feature of their intracellular environment rather than of the enzymes themselves. B. thetaiotaomicron possesses superoxide dismutase and peroxidases, and it can repair damaged enzymes. However, measurements confirmed that the rate of reactive oxygen species production inside aerated B. thetaiotaomicron is far higher than in E. coli Analysis of the damaged enzymes recovered from aerated B. thetaiotaomicron suggested that they had been inactivated by superoxide rather than by hydrogen peroxide. Accordingly, overproduction of superoxide dismutase substantially protected the enzymes from aeration. We conclude that when this anaerobe encounters oxygen, its internal superoxide levels rise high enough to inactivate key catabolic and biosynthetic enzymes. Superoxide thus comprises a major element of the oxygen sensitivity of this anaerobe. The extent to which molecular oxygen exerts additional direct effects remains to be determined.
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71
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Zhang YH, Lin JY, Bai L, Huang M, Chen HQ, Yao S, Lyu SX. Antioxidant capacities of Bacillus endophyticus ST-1 and Ketogulonicigenium vulgare 25B-1 in vitamin C fermentation. BIOTECHNOL BIOTEC EQ 2018. [DOI: 10.1080/13102818.2018.1447854] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Affiliation(s)
- Yun-he Zhang
- Laboratory of Food Microorganisms, College of Food Science, Shenyang Agricultural University, Shenyang, Liaoning, PR China
| | - Jie-ye Lin
- Department of Biochemistry and Molecular Biology, College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, Liaoning, PR China
| | - Ling Bai
- Department of Biochemistry and Molecular Biology, College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, Liaoning, PR China
| | - Mao Huang
- Department of Biochemistry and Molecular Biology, College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, Liaoning, PR China
| | - Hong-quan Chen
- Research and Development Department, Northeast Pharmaceutical General Factory of Vitamin C Company, Shenyang, Liaoning, PR China
| | - Shuo Yao
- Department of Biochemistry and Molecular Biology, College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, Liaoning, PR China
| | - Shu-xia Lyu
- Department of Biochemistry and Molecular Biology, College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, Liaoning, PR China
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72
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Beal NJ, Corry TA, O'Malley PJ. Comparison of Experimental and Broken Symmetry Density Functional Theory Calculated Electron Paramagnetic Resonance Parameters for the Manganese Catalase Active Site in the Superoxidized Mn III/Mn IV State. J Phys Chem B 2018; 122:2881-2890. [PMID: 29470911 DOI: 10.1021/acs.jpcb.7b11649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Broken symmetry density functional theory has been used to calculate g-tensor, 55Mn, 14N, and 17O hyperfine couplings for active site models of superoxidized MnIII/MnIV manganese catalase both in its native and azide-inhibited form. While a good agreement is found between the calculated and experimental g-tensor and 55Mn hyperfine couplings for all models, the active site geometry and Mn ion oxidation state can only be readily distinguished based on a comparison of the calculated and experimental 14N azide and 17O HFCs. This comparison shows that only models containing a Jahn-Teller distorted 5-coordinate (MnIII)2 site and a 6-coordinate (MnIV)1 site can satisfactorily reproduce the experimental 14N and 17O hyperfine couplings.
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Affiliation(s)
- Nathan J Beal
- School of Chemistry , The University of Manchester , Manchester M13 9PL , U.K
| | - Thomas A Corry
- School of Chemistry , The University of Manchester , Manchester M13 9PL , U.K
| | - Patrick J O'Malley
- School of Chemistry , The University of Manchester , Manchester M13 9PL , U.K
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73
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Iwadate Y, Kato JI. Involvement of the ytfK gene from the PhoB regulon in stationary-phase H 2 O 2 stress tolerance in Escherichia coli. Microbiology (Reading) 2017; 163:1912-1923. [DOI: 10.1099/mic.0.000534] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Yumi Iwadate
- Department of Biological Sciences, Graduate Schools of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Jun-ichi Kato
- Department of Biological Sciences, Graduate Schools of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan
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74
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Bak EN, Larsen MG, Moeller R, Nissen SB, Jensen LR, Nørnberg P, Jensen SJK, Finster K. Silicates Eroded under Simulated Martian Conditions Effectively Kill Bacteria-A Challenge for Life on Mars. Front Microbiol 2017; 8:1709. [PMID: 28955310 PMCID: PMC5601068 DOI: 10.3389/fmicb.2017.01709] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 08/23/2017] [Indexed: 11/17/2022] Open
Abstract
The habitability of Mars is determined by the physical and chemical environment. The effect of low water availability, temperature, low atmospheric pressure and strong UV radiation has been extensively studied in relation to the survival of microorganisms. In addition to these stress factors, it was recently found that silicates exposed to simulated saltation in a Mars-like atmosphere can lead to a production of reactive oxygen species. Here, we have investigated the stress effect induced by quartz and basalt abraded in Mars-like atmospheres by examining the survivability of the three microbial model organisms Pseudomonas putida, Bacillus subtilis, and Deinococcus radiodurans upon exposure to the abraded silicates. We found that abraded basalt that had not been in contact with oxygen after abrasion killed more than 99% of the vegetative cells while endospores were largely unaffected. Exposure of the basalt samples to oxygen after abrasion led to a significant reduction in the stress effect. Abraded quartz was generally less toxic than abraded basalt. We suggest that the stress effect of abraded silicates may be caused by a production of reactive oxygen species and enhanced by transition metal ions in the basalt leading to hydroxyl radicals through Fenton-like reactions. The low survivability of the usually highly resistant D. radiodurans indicates that the effect of abraded silicates, as is ubiquitous on the Martian surface, would limit the habitability of Mars as well as the risk of forward contamination. Furthermore, the reactivity of abraded silicates could have implications for future manned missions, although the lower effect of abraded silicates exposed to oxygen suggests that the effects would be reduced in human habitats.
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Affiliation(s)
- Ebbe N Bak
- Department of Bioscience, Aarhus UniversityAarhus, Denmark
| | | | - Ralf Moeller
- Space Microbiology Research Group, Institute of Aerospace Medicine, German Aerospace Center (DLR)Cologne, Germany
| | - Silas B Nissen
- Department of Bioscience, Aarhus UniversityAarhus, Denmark
| | - Lasse R Jensen
- Department of Bioscience, Aarhus UniversityAarhus, Denmark
| | - Per Nørnberg
- Department of Bioscience, Aarhus UniversityAarhus, Denmark
| | | | - Kai Finster
- Department of Bioscience, Aarhus UniversityAarhus, Denmark.,Stellar Astrophysics Center, Department of Physics and Astronomy, Aarhus UniversityAarhus, Denmark
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75
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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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76
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Cytochrome c peroxidase facilitates the beneficial use of H 2O 2 in prokaryotes. Proc Natl Acad Sci U S A 2017; 114:8678-8680. [PMID: 28765365 DOI: 10.1073/pnas.1710943114] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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77
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Abstract
Cytochrome bd is a unique prokaryotic respiratory terminal oxidase that does not belong to the extensively investigated family of haem-copper oxidases (HCOs). The enzyme catalyses the four-electron reduction of O2 to 2H2O, using quinols as physiological reducing substrates. The reaction is electrogenic and cytochrome bd therefore sustains bacterial energy metabolism by contributing to maintain the transmembrane proton motive force required for ATP synthesis. As compared to HCOs, cytochrome bd displays several distinctive features in terms of (i) metal composition (it lacks Cu and harbours a d-type haem in addition to two haems b), (ii) overall three-dimensional structure, that only recently has been solved, and arrangement of the redox cofactors, (iii) lesser energetic efficiency (it is not a proton pump), (iv) higher O2 affinity, (v) higher resistance to inhibitors such as cyanide, nitric oxide (NO) and hydrogen sulphide (H2S) and (vi) ability to efficiently metabolize potentially toxic reactive oxygen and nitrogen species like hydrogen peroxide (H2O2) and peroxynitrite (ONOO-). Compelling evidence suggests that, beyond its bioenergetic role, cytochrome bd plays multiple functions in bacterial physiology and affords protection against oxidative and nitrosative stress. Relevant to human pathophysiology, thanks to its peculiar properties, the enzyme has been shown to promote virulence in several bacterial pathogens, being currently recognized as a target for the development of new antibiotics. This review aims to give an update on our current understanding of bd-type oxidases with a focus on their reactivity with gaseous ligands and its potential impact on bacterial physiology and human pathophysiology.
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78
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Kashyap DR, Kuzma M, Kowalczyk DA, Gupta D, Dziarski R. Bactericidal peptidoglycan recognition protein induces oxidative stress in Escherichia coli through a block in respiratory chain and increase in central carbon catabolism. Mol Microbiol 2017. [PMID: 28621879 DOI: 10.1111/mmi.13733] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mammalian Peptidoglycan Recognition Proteins (PGRPs) kill both Gram-positive and Gram-negative bacteria through simultaneous induction of oxidative, thiol and metal stress responses in bacteria. However, metabolic pathways through which PGRPs induce these bactericidal stress responses are unknown. We screened Keio collection of Escherichia coli deletion mutants and revealed that deleting genes for respiratory chain flavoproteins or for tricarboxylic acid (TCA) cycle resulted in increased resistance of E. coli to PGRP killing. PGRP-induced killing depended on the production of hydrogen peroxide, which required increased supply of NADH for respiratory chain oxidoreductases from central carbon catabolism (glycolysis and TCA cycle), and was controlled by cAMP-Crp. Bactericidal PGRP induced a rapid decrease in respiration, which suggested that the main source of increased production of hydrogen peroxide was a block in respiratory chain and diversion of electrons from NADH oxidoreductases to oxygen. CpxRA two-component system was a negative regulator of PGRP-induced oxidative stress. By contrast, PGRP-induced thiol stress (depletion of thiols) and metal stress (increase in intracellular free Zn2+ through influx of extracellular Zn2+ ) were mostly independent of oxidative stress. Thus, manipulating pathways that induce oxidative, thiol and metal stress in bacteria could be a useful strategy to design new approaches to antibacterial therapy.
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Affiliation(s)
- Des R Kashyap
- Indiana University, School of Medicine-Northwest, Gary, IN, 46408, USA
| | - Marcin Kuzma
- Indiana University, School of Medicine-Northwest, Gary, IN, 46408, USA
| | | | - Dipika Gupta
- Indiana University, School of Medicine-Northwest, Gary, IN, 46408, USA
| | - Roman Dziarski
- Indiana University, School of Medicine-Northwest, Gary, IN, 46408, USA
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Bouvet O, Bourdelier E, Glodt J, Clermont O, Denamur E. Diversity of the auxotrophic requirements in natural isolates of Escherichia coli. MICROBIOLOGY-SGM 2017; 163:891-899. [PMID: 28651684 DOI: 10.1099/mic.0.000482] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Isolates of Escherichia coli, except Shigella, are generally prototrophic; they do not require any growth factors to grow in mineral medium. However, a nicotinic acid requirement is common among B2 phylogroup STc95 O18 E. coli clone strains. Nicotinic acid is a precursor of nicotinamide adenine dinucleotide (NAD), an essential molecule that plays central role in cellular metabolism. The defect in NAD synthesis of these strains is due to alterations in de novo biosynthesis pathway nadB gene. Here, by studying growth on minimal medium with glycolytic (glucose) or gluconeogenic (pyruvate or succinate) substrates as the carbon supply in a large panel of E. coli natural isolates representative of the species diversity, we identify an absolute nicotinic acid requirement in non-STc95 strains due in one case to a nadA inactivation. The growth on glucose medium of some extraintestinal pathogenic E. coli strains belonging to various non-O18 B2 phylogroup STc95 clones is restored either by aspartate or nicotinate, demonstrating that the nicotinic acid requirement can also be due to an intracellular aspartate depletion. The auxotrophic requirements depend on the carbon source available in the environment. Moreover, some strains prototrophic in glucose medium become auxotrophic in succinate medium, and conversely, some strainsauxotrophic in glucose medium become prototrophic in succinate medium. Finally, a partial depletion of intracellular aspartate can be observed in some prototrophic strains belonging to various phylogroups. The observed more or less significant depletion according to isolates may be due to differences in tricarboxylic acid cycle enzyme activities. These metabolic defects could be involved in the adaptation of E. coli to its various niches.
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Affiliation(s)
- Odile Bouvet
- IAME, UMR 1137, INSERM, Univ Paris Diderot, Sorbonne Paris Cité, F-75018, Paris, France
| | - Emmanuelle Bourdelier
- IAME, UMR 1137, INSERM, Univ Paris Diderot, Sorbonne Paris Cité, F-75018, Paris, France
| | - Jeremy Glodt
- IAME, UMR 1137, INSERM, Univ Paris Diderot, Sorbonne Paris Cité, F-75018, Paris, France
| | - Olivier Clermont
- IAME, UMR 1137, INSERM, Univ Paris Diderot, Sorbonne Paris Cité, F-75018, Paris, France
| | - Erick Denamur
- AP-HP, Laboratoire de Génétique Moléculaire, Hôpital Bichat, F-75018, Paris, France.,IAME, UMR 1137, INSERM, Univ Paris Diderot, Sorbonne Paris Cité, F-75018, Paris, France
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80
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Lv Y, Cheng X, Du G, Zhou J, Chen J. Engineering of an H 2 O 2 auto-scavenging in vivo cascade for pinoresinol production. Biotechnol Bioeng 2017; 114:2066-2074. [PMID: 28436004 DOI: 10.1002/bit.26319] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 04/16/2017] [Accepted: 04/19/2017] [Indexed: 01/16/2023]
Abstract
Pinoresinol is a natural lignan with a high market value that has potential pharmacological and food supplement applications. Pinoresinol is currently isolated from plants, which suffers from low efficiency and yield. To produce pinoresinol from inexpensive and industrially available eugenol, an in vivo enzymatic cascade composed of vanillyl alcohol oxidase and peroxidase was designed, which scavenges H2 O2 automatically and eliminates protein purification and cofactor addition. Two peroxidases were screened and identified from Escherichia coli BL21 (DE3), and tested in the enzymatic cascade. To balance the flux, different genetic architectures were constructed by using ePathBrick and fusion gene approaches. Scavenging H2 O2 alleviated by-product toxicity and enzyme inhibition, and led to efficient pinoresinol production. Optimization of the reaction conditions achieved a titer of 11.29 g/L pinoresinol. The molar yield and productivity were 52.77% and 1.03 g/(L × h), respectively. The elegant strategy developed herein utilizes the harmful by-product to drive the biosynthetic reaction forward and simultaneously detoxify cells, thereby preventing enzyme inhibition. Biotechnol. Bioeng. 2017;114: 2066-2074. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Yongkun Lv
- Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
| | - Xiaozhong Cheng
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Guocheng Du
- Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
| | - Jingwen Zhou
- Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
| | - Jian Chen
- Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
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81
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Dalecki AG, Crawford CL, Wolschendorf F. Copper and Antibiotics: Discovery, Modes of Action, and Opportunities for Medicinal Applications. Adv Microb Physiol 2017; 70:193-260. [PMID: 28528648 DOI: 10.1016/bs.ampbs.2017.01.007] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Copper is a ubiquitous element in the environment as well as living organisms, with its redox capabilities and complexation potential making it indispensable for many cellular functions. However, these same properties can be highly detrimental to prokaryotes and eukaryotes when not properly controlled, damaging many biomolecules including DNA, lipids, and proteins. To restrict free copper concentrations, all bacteria have developed mechanisms of resistance, sequestering and effluxing labile copper to minimize its deleterious effects. This weakness is actively exploited by phagocytes, which utilize a copper burst to destroy pathogens. Though administration of free copper is an unreasonable therapeutic antimicrobial itself, due to insufficient selectivity between host and pathogen, small-molecule ligands may provide an opportunity for therapeutic mimicry of the immune system. By modulating cellular entry, complex stability, resistance evasion, and target selectivity, ligand/metal coordination complexes can synergistically result in high levels of antibacterial activity. Several established therapeutic drugs, such as disulfiram and pyrithione, display remarkable copper-dependent inhibitory activity. These findings have led to development of new drug discovery techniques, using copper ions as the focal point. High-throughput screens for copper-dependent inhibitors against Mycobacterium tuberculosis and Staphylococcus aureus uncovered several new compounds, including a new class of inhibitors, the NNSNs. In this review, we highlight the microbial biology of copper, its antibacterial activities, and mechanisms to discover new inhibitors that synergize with copper.
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Affiliation(s)
- Alex G Dalecki
- The University of Alabama at Birmingham, Birmingham, AL, United States
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82
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Solyanikova IP, Suzina NE, Emelyanova EV, Polivtseva VN, Pshenichnikova AB, Lobanok AG, Golovleva LA. Morphological, physiological, and biochemical characteristics of a benzoate-degrading strain Rhodococcus opacus 1CP under stress conditions. Microbiology (Reading) 2017. [DOI: 10.1134/s0026261717020199] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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83
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Loss of OxyR reduces efficacy of oxygen respiration in Shewanella oneidensis. Sci Rep 2017; 7:42609. [PMID: 28195212 PMCID: PMC5307378 DOI: 10.1038/srep42609] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 01/11/2017] [Indexed: 02/02/2023] Open
Abstract
In many bacteria, OxyR is the major regulator controlling cellular response to H2O2. A common phenotype resulting from OxyR loss is reduced growth rate, but the underlying mechanism is unknown. We demonstrated in Shewanella oneidensis, an important research model for applied and environmental microbes, that the defect is primarily due to an electron shortage to major terminal oxidase cytochrome cbb3. The loss of OxyR leads to enhanced production of electron carriers that compete for electrons against cytochrome cbb3, cytochrome bd in particular. We further showed that the oxyR mutation also results in increased production of menaquinone, an additional means to lessen electrons to cytochrome cbb3. Although regulation of OxyR on these biological processes appears to be indirect, these data indicate that the regulator plays a previously underappreciated role in mediating respiration.
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Charbon G, Campion C, Chan SHJ, Bjørn L, Weimann A, da Silva LCN, Jensen PR, Løbner-Olesen A. Re-wiring of energy metabolism promotes viability during hyperreplication stress in E. coli. PLoS Genet 2017; 13:e1006590. [PMID: 28129339 PMCID: PMC5302844 DOI: 10.1371/journal.pgen.1006590] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 02/10/2017] [Accepted: 01/18/2017] [Indexed: 11/23/2022] Open
Abstract
Chromosome replication in Escherichia coli is initiated by DnaA. DnaA binds ATP which is essential for formation of a DnaA-oriC nucleoprotein complex that promotes strand opening, helicase loading and replisome assembly. Following initiation, DnaAATP is converted to DnaAADP primarily by the Regulatory Inactivation of DnaA process (RIDA). In RIDA deficient cells, DnaAATP accumulates leading to uncontrolled initiation of replication and cell death by accumulation of DNA strand breaks. Mutations that suppress RIDA deficiency either dampen overinitiation or permit growth despite overinitiation. We characterize mutations of the last group that have in common that distinct metabolic routes are rewired resulting in the redirection of electron flow towards the cytochrome bd-1. We propose a model where cytochrome bd-1 lowers the formation of reactive oxygen species and hence oxidative damage to the DNA in general. This increases the processivity of replication forks generated by overinitiation to a level that sustains viability. In most bacteria chromosome replication is initiated by the DnaA protein. In Escherichia coli, DnaA binds ATP and ADP with similar affinity but only the ATP bound form is active. An increased level of DnaAATP causes overinitiation and cell death by accumulation of DNA strand breaks. These strand breaks often result from forks encountering gapped DNA formed during repair of oxidative damage. We provide evidence that cell death in overinitiating cells can be prevented by rewiring the metabolism to favor the micro-aerobic respiratory chain with the cytochrome bd-1 as terminal oxidase. Cytochrome bd-1 is found in aerobic as well as anaerobic bacteria. Its role is to reduce O2 in micro-aerobic conditions and work as an electron sink to prevent the formation of reactive oxygen species. Our results suggest that bacteria can cope with replication stress by increasing respiration through cytochrome bd-1 to reduce the formation of reactive oxygen species, and hence oxidative damage to a level that does not interfere with replication fork progression.
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Affiliation(s)
- Godefroid Charbon
- Dept. of Biology, Section for Functional Genomics and Center for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, Denmark
| | - Christopher Campion
- Dept. of Biology, Section for Functional Genomics and Center for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, Denmark
| | - Siu Hung Joshua Chan
- National Food Institute, Microbial Biotechnology and Biorefining, Technical University of Denmark, Lyngby, Denmark
| | - Louise Bjørn
- Dept. of Biology, Section for Functional Genomics and Center for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, Denmark
| | - Allan Weimann
- Laboratory of Clinical Pharmacology, Rigshospitalet, Section Q7642, Copenhagen Denmark and Department of Clinical Pharmacology, Bispebjerg Frederiksberg Hospitals, Copenhagen Denmark
| | - Luís Cláudio Nascimento da Silva
- Dept. of Biology, Section for Functional Genomics and Center for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, Denmark
| | - Peter Ruhdal Jensen
- National Food Institute, Microbial Biotechnology and Biorefining, Technical University of Denmark, Lyngby, Denmark
| | - Anders Løbner-Olesen
- Dept. of Biology, Section for Functional Genomics and Center for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
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The Fumarate Reductase of Bacteroides thetaiotaomicron, unlike That of Escherichia coli, Is Configured so that It Does Not Generate Reactive Oxygen Species. mBio 2017; 8:mBio.01873-16. [PMID: 28049145 PMCID: PMC5210497 DOI: 10.1128/mbio.01873-16] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The impact of oxidative stress upon organismal fitness is most apparent in the phenomenon of obligate anaerobiosis. The root cause may be multifaceted, but the intracellular generation of reactive oxygen species (ROS) likely plays a key role. ROS are formed when redox enzymes accidentally transfer electrons to oxygen rather than to their physiological substrates. In this study, we confirm that the predominant intestinal anaerobe Bacteroides thetaiotaomicron generates intracellular ROS at a very high rate when it is aerated. Fumarate reductase (Frd) is a prominent enzyme in the anaerobic metabolism of many bacteria, including B. thetaiotaomicron, and prior studies of Escherichia coli Frd showed that the enzyme is unusually prone to ROS generation. Surprisingly, in this study biochemical analysis demonstrated that the B. thetaiotaomicron Frd does not react with oxygen at all: neither superoxide nor hydrogen peroxide is formed. Subunit-swapping experiments indicated that this difference does not derive from the flavoprotein subunit at which ROS normally arise. Experiments with the related enzyme succinate dehydrogenase discouraged the hypothesis that heme moieties are responsible. Thus, resistance to oxidation may reflect a shift of electron density away from the flavin moiety toward the iron-sulfur clusters. This study shows that the autoxidizability of a redox enzyme can be suppressed by subtle modifications that do not compromise its physiological function. One implication is that selective pressures might enhance the oxygen tolerance of an organism by manipulating the electronic properties of its redox enzymes so they do not generate ROS. IMPORTANCE Whether in sediments or pathogenic biofilms, the structures of microbial communities are configured around the sensitivities of their members to oxygen. Oxygen triggers the intracellular formation of reactive oxygen species (ROS), and the sensitivity of a microbe to oxygen likely depends upon the rates at which ROS are formed inside it. This study supports that idea, as an obligate anaerobe was confirmed to generate ROS very rapidly upon aeration. However, the suspected source of the ROS was disproven, as the fumarate reductase of the anaerobe did not display the high oxidation rate of its E. coli homologue. Evidently, adjustments in its electronic structure can suppress the tendency of an enzyme to generate ROS. Importantly, this outcome suggests that evolutionary pressure may succeed in modifying redox enzymes and thereby diminishing the stress that an organism experiences in oxic environments. The actual source of ROS in the anaerobe remains to be discovered.
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86
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Abstract
Like most bacteria, Escherichia coli has a flexible and branched respiratory chain that enables the prokaryote to live under a variety of environmental conditions, from highly aerobic to completely anaerobic. In general, the bacterial respiratory chain is composed of dehydrogenases, a quinone pool, and reductases. Substrate-specific dehydrogenases transfer reducing equivalents from various donor substrates (NADH, succinate, glycerophosphate, formate, hydrogen, pyruvate, and lactate) to a quinone pool (menaquinone, ubiquinone, and dimethylmenoquinone). Then electrons from reduced quinones (quinols) are transferred by terminal reductases to different electron acceptors. Under aerobic growth conditions, the terminal electron acceptor is molecular oxygen. A transfer of electrons from quinol to O₂ is served by two major oxidoreductases (oxidases), cytochrome bo₃ encoded by cyoABCDE and cytochrome bd encoded by cydABX. Terminal oxidases of aerobic respiratory chains of bacteria, which use O₂ as the final electron acceptor, can oxidize one of two alternative electron donors, either cytochrome c or quinol. This review compares the effects of different inhibitors on the respiratory activities of cytochrome bo₃ and cytochrome bd in E. coli. It also presents a discussion on the genetics and the prosthetic groups of cytochrome bo₃ and cytochrome bd. The E. coli membrane contains three types of quinones that all have an octaprenyl side chain (C₄₀). It has been proposed that the bo₃ oxidase can have two ubiquinone-binding sites with different affinities. "WHAT'S NEW" IN THE REVISED ARTICLE: The revised article comprises additional information about subunit composition of cytochrome bd and its role in bacterial resistance to nitrosative and oxidative stresses. Also, we present the novel data on the electrogenic function of appBCX-encoded cytochrome bd-II, a second bd-type oxidase that had been thought not to contribute to generation of a proton motive force in E. coli, although its spectral properties closely resemble those of cydABX-encoded cytochrome bd.
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87
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Cytochrome bd Displays Significant Quinol Peroxidase Activity. Sci Rep 2016; 6:27631. [PMID: 27279363 PMCID: PMC4899803 DOI: 10.1038/srep27631] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 05/23/2016] [Indexed: 12/29/2022] Open
Abstract
Cytochrome bd is a prokaryotic terminal oxidase that catalyses the electrogenic reduction of oxygen to water using ubiquinol as electron donor. Cytochrome bd is a tri-haem integral membrane enzyme carrying a low-spin haem b558, and two high-spin haems: b595 and d. Here we show that besides its oxidase activity, cytochrome bd from Escherichia coli is a genuine quinol peroxidase (QPO) that reduces hydrogen peroxide to water. The highly active and pure enzyme preparation used in this study did not display the catalase activity recently reported for E. coli cytochrome bd. To our knowledge, cytochrome bd is the first membrane-bound quinol peroxidase detected in E. coli. The observation that cytochrome bd is a quinol peroxidase, can provide a biochemical basis for its role in detoxification of hydrogen peroxide and may explain the frequent findings reported in the literature that indicate increased sensitivity to hydrogen peroxide and decreased virulence in mutants that lack the enzyme.
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88
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De Martino M, Ershov D, van den Berg PJ, Tans SJ, Meyer AS. Single-Cell Analysis of the Dps Response to Oxidative Stress. J Bacteriol 2016; 198:1662-1674. [PMID: 27021559 PMCID: PMC4959295 DOI: 10.1128/jb.00239-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 03/20/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Microorganisms have developed an elaborate spectrum of mechanisms to respond and adapt to environmental stress conditions. Among these is the expression of dps, coding for the DNA-binding protein from starved cells. Dps becomes the dominant nucleoid-organizing protein in stationary-phase Escherichia coli cells and is required for robust survival under stress conditions, including carbon or nitrogen starvation, oxidative stress, metal exposure, and irradiation. To study the complex regulation of Dps in E. coli, we utilized time-lapse fluorescence microscopy imaging to examine the kinetics, input encoding, and variability of the Dps response in single cells. In the presence of an oxidative stressor, we observed a single pulse of activation of Dps production. Increased concentrations of H2O2 led to increased intensity and duration of the pulse. While lower concentrations of H2O2 robustly activated the Dps response with little effect on the growth rate, higher concentrations of H2O2 resulted in dramatically lower and highly varied growth rates. A comparison of cells exposed to the same concentration of H2O2 revealed that increased levels of Dps expression did not confer a growth advantage, indicating that recovery from stress may rely primarily upon variation in the amount of damage caused to individual cells. IMPORTANCE We show for the first time the response of the DNA-binding protein from starved cells (Dps) to oxidative stress in single cells of E. coli Through time-lapse fluorescence microscopy, a single pulse of Dps production is observed in cells exposed to H2O2, with a duration and intensity of induction proportional to the concentration of the applied stress. More intense Dps expression did not provide a growth benefit to the bacteria, suggesting that healing from oxidative stress may largely depend upon the amount of damage in each individual cell.
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Affiliation(s)
- Michela De Martino
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | | | - Peter J van den Berg
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | | | - Anne S Meyer
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
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Siletsky SA, Rappaport F, Poole RK, Borisov VB. Evidence for Fast Electron Transfer between the High-Spin Haems in Cytochrome bd-I from Escherichia coli. PLoS One 2016; 11:e0155186. [PMID: 27152644 PMCID: PMC4859518 DOI: 10.1371/journal.pone.0155186] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 04/25/2016] [Indexed: 12/21/2022] Open
Abstract
Cytochrome bd-I is one of the three proton motive force-generating quinol oxidases in the O2-dependent respiratory chain of Escherichia coli. It contains one low-spin haem (b558) and the two high-spin haems (b595 and d) as the redox-active cofactors. In order to examine the flash-induced intraprotein reverse electron transfer (the so-called ''electron backflow''), CO was photolyzed from the ferrous haem d in one-electron reduced (b5583+b5953+d2+-CO) cytochrome bd-I, and the fully reduced (b5582+b5952+d2+-CO) oxidase as a control. In contrast to the fully reduced cytochrome bd-I, the transient spectrum of one-electron reduced oxidase at a delay time of 1.5 μs is clearly different from that at a delay time of 200 ns. The difference between the two spectra can be modeled as the electron transfer from haem d to haem b595 in 3–4% of the cytochrome bd-I population. Thus, the interhaem electron backflow reaction induced by photodissociation of CO from haem d in one-electron reduced cytochrome bd-I comprises two kinetically different phases: the previously unnoticed fast electron transfer from haem d to haem b595 within 0.2–1.5 μs and the slower well-defined electron equilibration with τ ~16 μs. The major new finding of this work is the lack of electron transfer at 200 ns.
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Affiliation(s)
- Sergey A. Siletsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
- * E-mail: (VBB); (SAS); (RKP)
| | - Fabrice Rappaport
- Institut de Biologie Physico-Chimique, Unite Mixte de Recherche 7141 CNRS, Universite Paris 6, Paris, France
| | - Robert K. Poole
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, United Kingdom
- * E-mail: (VBB); (SAS); (RKP)
| | - Vitaliy B. Borisov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
- * E-mail: (VBB); (SAS); (RKP)
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90
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Song M, Kim JS, Liu L, Husain M, Vázquez-Torres A. Antioxidant Defense by Thioredoxin Can Occur Independently of Canonical Thiol-Disulfide Oxidoreductase Enzymatic Activity. Cell Rep 2016; 14:2901-11. [PMID: 26997275 DOI: 10.1016/j.celrep.2016.02.066] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 01/21/2016] [Accepted: 02/15/2016] [Indexed: 01/21/2023] Open
Abstract
The thiol-disulfide oxidoreductase CXXC catalytic domain of thioredoxin contributes to antioxidant defense in phylogenetically diverse organisms. We find that although the oxidoreductase activity of thioredoxin-1 protects Salmonella enterica serovar Typhimurium from hydrogen peroxide in vitro, it does not appear to contribute to Salmonella's antioxidant defenses in vivo. Nonetheless, thioredoxin-1 defends Salmonella from oxidative stress resulting from NADPH phagocyte oxidase macrophage expression during the innate immune response in mice. Thioredoxin-1 binds to the flexible linker, which connects the receiver and effector domains of SsrB, thereby keeping this response regulator in the soluble fraction. Thioredoxin-1, independently of thiol-disulfide exchange, activates intracellular SPI2 gene transcription required for Salmonella resistance to both reactive species generated by NADPH phagocyte oxidase and oxygen-independent lysosomal host defenses. These findings suggest that the horizontally acquired virulence determinant SsrB is regulated post-translationally by ancestrally present thioredoxin.
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Affiliation(s)
- Miryoung Song
- Department of Immunology and Microbiology, University of Colorado School of Medicine, 12800 East 19(th) Avenue, Aurora, CO 80045, USA
| | - Ju-Sim Kim
- Department of Immunology and Microbiology, University of Colorado School of Medicine, 12800 East 19(th) Avenue, Aurora, CO 80045, USA
| | - Lin Liu
- Department of Immunology and Microbiology, University of Colorado School of Medicine, 12800 East 19(th) Avenue, Aurora, CO 80045, USA
| | - Maroof Husain
- Department of Immunology and Microbiology, University of Colorado School of Medicine, 12800 East 19(th) Avenue, Aurora, CO 80045, USA; Division of Molecular and Translational Biomedicine, Department of Anesthesiology and Perioperative Medicine, University of Alabama, Birmingham, 619 South 19(th) Street, Birmingham, AL 35249-6810, USA
| | - Andrés Vázquez-Torres
- Department of Immunology and Microbiology, University of Colorado School of Medicine, 12800 East 19(th) Avenue, Aurora, CO 80045, USA; Veterans Affairs Eastern Colorado Health Care System, 1055 Clermont Street, Denver, CO 80220, USA.
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91
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Insights into the Function of a Second, Nonclassical Ahp Peroxidase, AhpA, in Oxidative Stress Resistance in Bacillus subtilis. J Bacteriol 2016; 198:1044-57. [PMID: 26787766 DOI: 10.1128/jb.00679-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 01/12/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Organisms growing aerobically generate reactive oxygen-containing molecules, such as hydrogen peroxide (H2O2). These reactive oxygen molecules damage enzymes and DNA and may even cause cell death. In response, Bacillus subtilis produces at least nine potential peroxide-scavenging enzymes, two of which appear to be the primary enzymes responsible for detoxifying peroxides during vegetative growth: a catalase (encoded by katA) and an alkylhydroperoxide reductase (Ahp, encoded by ahpC). AhpC uses two redox-active cysteine residues to reduce peroxides to nontoxic molecules. A specialized thioredoxin-like protein, AhpF, is then required to restore oxidized AhpC back to its reduced state. Curiously, B. subtilis has two genes encoding Ahp: ahpC and ahpA. Although AhpC is well characterized, very little is known about AhpA. In fact, numerous bacterial species have multiple ahp genes; however, these additional Ahp proteins are generally uncharacterized. We seek to understand the role of AhpA in the bacterium's defense against toxic peroxide molecules in relation to the roles previously assigned to AhpC and catalase. Our results demonstrate that AhpA has catalytic activity similar to that of the primary enzyme, AhpC. Furthermore, our results suggest that a unique thioredoxin redox protein, AhpT, may reduce AhpA upon its oxidation by peroxides. However, unlike AhpC, which is expressed well during vegetative growth, our results suggest that AhpA is expressed primarily during postexponential growth. IMPORTANCE B. subtilis appears to produce nine enzymes designed to protect cells against peroxides; two belong to the Ahp class of peroxidases. These studies provide an initial characterization of one of these Ahp homologs and demonstrate that the two Ahp enzymes are not simply replicates of each other, suggesting that they instead are expressed at different times during growth of the cells. These results highlight the need to further study the Ahp homologs to better understand how they differ from one another and to identify their function, if any, in protection against oxidative stress. Through these studies, we may better understand why bacteria have multiple enzymes designed to scavenge peroxides and thus have a more accurate understanding of oxidative stress resistance.
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92
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Adherent-invasive Escherichia coli Exacerbates Antibiotic-associated Intestinal Dysbiosis and Neutrophil Extracellular Trap Activation. Inflamm Bowel Dis 2016; 22:42-54. [PMID: 26398709 DOI: 10.1097/mib.0000000000000591] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND Antibiotic-associated disruption of the gut microbiota is a known risk factor for Crohn's disease. This chronic inflammatory disorder results from aberrant host immune responses to subsets of the gut microbiota, and is characterized by intense neutrophil recruitment to the lamina propria, surface and crypt epithelium. Importantly, adherent-invasive Escherichia coli (AIEC) is abundant in ileal biopsies, highlighting a possible etiological role. In this study, we investigated the impact of antibiotics and AIEC challenge on murine intestinal dysbiosis and neutrophil extracellular trap activation, which is a critical component of the neutrophil antimicrobial repertoire. METHODS Male C57BL/6 mice were administered vancomycin and gentamicin (once daily, 3 days), and subsequently challenged with AIEC strain LF82 (once daily, 2 days). Perturbation of the gut microbiota was monitored using a combination of molecular and phylogenetic analyses. The impact of commensal and dysbiotic gut bacterial communities on neutrophil extracellular trap mobilization and intestinal redox balance was also quantified. RESULTS Exposure of neutrophils to murine commensal gut microbial communities activated neutrophil extracellular trap formation. The capacity of neutrophils to cast these web-like structures was exacerbated following antibiotic and AIEC-associated intestinal dysbiosis, highlighting the possible overgrowth of immune-activating intestinal pathobionts. Intestinal dysbiosis was associated with an elevated capacity of the cultivated gut bacteria to produce reactive oxygen species in vitro, and increased colonic oxidative stress in vivo. CONCLUSIONS Together, these data provide new insights into the detrimental effects of antibiotics on the gut microbiota, with clinically relevant implications for intestinal dysbiosis on neutrophil function and intestinal redox balance.
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Campillo-Brocal JC, Lucas-Elío P, Sanchez-Amat A. Distribution in Different Organisms of Amino Acid Oxidases with FAD or a Quinone As Cofactor and Their Role as Antimicrobial Proteins in Marine Bacteria. Mar Drugs 2015; 13:7403-18. [PMID: 26694422 PMCID: PMC4699246 DOI: 10.3390/md13127073] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 11/27/2015] [Accepted: 12/08/2015] [Indexed: 12/27/2022] Open
Abstract
Amino acid oxidases (AAOs) catalyze the oxidative deamination of amino acids releasing ammonium and hydrogen peroxide. Several kinds of these enzymes have been reported. Depending on the amino acid isomer used as a substrate, it is possible to differentiate between l-amino acid oxidases and d-amino acid oxidases. Both use FAD as cofactor and oxidize the amino acid in the alpha position releasing the corresponding keto acid. Recently, a novel class of AAOs has been described that does not contain FAD as cofactor, but a quinone generated by post-translational modification of residues in the same protein. These proteins are named as LodA-like proteins, after the first member of this group described, LodA, a lysine epsilon oxidase synthesized by the marine bacterium Marinomonas mediterranea. In this review, a phylogenetic analysis of all the enzymes described with AAO activity has been performed. It is shown that it is possible to recognize different groups of these enzymes and those containing the quinone cofactor are clearly differentiated. In marine bacteria, particularly in the genus Pseudoalteromonas, most of the proteins described as antimicrobial because of their capacity to generate hydrogen peroxide belong to the group of LodA-like proteins.
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Affiliation(s)
- Jonatan C Campillo-Brocal
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain.
| | - Patricia Lucas-Elío
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain.
| | - Antonio Sanchez-Amat
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain.
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Leclerc J, Rosenfeld E, Trainini M, Martin B, Meuric V, Bonnaure-Mallet M, Baysse C. The Cytochrome bd Oxidase of Porphyromonas gingivalis Contributes to Oxidative Stress Resistance and Dioxygen Tolerance. PLoS One 2015; 10:e0143808. [PMID: 26629705 PMCID: PMC4668044 DOI: 10.1371/journal.pone.0143808] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 11/10/2015] [Indexed: 11/18/2022] Open
Abstract
Porphyromonas gingivalis is an etiologic agent of periodontal disease in humans. The disease is associated with the formation of a mixed oral biofilm which is exposed to oxygen and environmental stress, such as oxidative stress. To investigate possible roles for cytochrome bd oxidase in the growth and persistence of this anaerobic bacterium inside the oral biofilm, mutant strains deficient in cytochrome bd oxidase activity were characterized. This study demonstrated that the cytochrome bd oxidase of Porphyromonas gingivalis, encoded by cydAB, was able to catalyse O2 consumption and was involved in peroxide and superoxide resistance, and dioxygen tolerance.
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Affiliation(s)
- Julia Leclerc
- EA1254 Microbiologie—Risques Infectieux, University of Rennes1, Rennes, France
| | - Eric Rosenfeld
- UMR CNRS 7266 LIENSs, University of La Rochelle, La Rochelle, France
| | - Mathieu Trainini
- EA1254 Microbiologie—Risques Infectieux, University of Rennes1, Rennes, France
| | - Bénédicte Martin
- EA1254 Microbiologie—Risques Infectieux, University of Rennes1, Rennes, France
| | - Vincent Meuric
- EA1254 Microbiologie—Risques Infectieux, University of Rennes1, Rennes, France
- UMR CNRS 7266 LIENSs, University of La Rochelle, La Rochelle, France
- CHU Rennes, Rennes, France
| | - Martine Bonnaure-Mallet
- EA1254 Microbiologie—Risques Infectieux, University of Rennes1, Rennes, France
- UMR CNRS 7266 LIENSs, University of La Rochelle, La Rochelle, France
- CHU Rennes, Rennes, France
| | - Christine Baysse
- EA1254 Microbiologie—Risques Infectieux, University of Rennes1, Rennes, France
- * E-mail:
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95
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Hong EJ, Kim P, Kim ES, Kim Y, Lee HS. Involvement of the osrR gene in the hydrogen peroxide-mediated stress response of Corynebacterium glutamicum. Res Microbiol 2015; 167:20-8. [PMID: 26433092 DOI: 10.1016/j.resmic.2015.09.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 06/30/2015] [Accepted: 09/22/2015] [Indexed: 01/19/2023]
Abstract
A transcriptional profile of the H2O2-adapted Corynebacterium glutamicum HA strain reveals a list of upregulated regulatory genes. Among them, we selected ORF NCgl2298, designated osrR and analyzed its role in H2O2 adaptation. The osrR-deleted (ΔosrR) mutant had defective growth in minimal medium, which was even more pronounced in an osrR deletion mutant of an HA strain. The ΔosrR strain displayed increased sensitivity to H2O2. In addition to H2O2 sensitivity, the ΔosrR strain was found to be temperature-sensitive at 37 °C. 2D-PAGE analysis of the ΔosrR mutant found that MetE and several other proteins involved in redox metabolism were affected by the mutation. Accordingly, the NADPH/NADP(+) ratio of the ΔosrR strain (0.85) was much lower than that of the wild-type strain (2.01). In contrast, the NADH/NAD(+) ratio of the mutant (0.54) was considerably higher than that of the wild-type (0.21). Based on these findings, we propose that H2O2-detoxifying metabolic systems, excluding those involving catalase, are present in C. glutamicum and are regulated, in part, by osrR.
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Affiliation(s)
- Eun-Ji Hong
- Department of Biotechnology and Bioinformatics, Korea University, 2511 Sejong-ro, Sejong-si 339-700, Republic of Korea.
| | - Pil Kim
- Department of Biotechnology, The Catholic University of Korea, Bucheon, Gyeonggi 420-743, Republic of Korea.
| | - Eung-Soo Kim
- Department of Biological Engineering, Inha University, Incheon 402-751, Republic of Korea.
| | - Younhee Kim
- Department of Korean Medicine, Semyung University, 65 Semyeong-ro, Jecheon-si, Chungbuk 390-711, Republic of Korea.
| | - Heung-Shick Lee
- Department of Biotechnology and Bioinformatics, Korea University, 2511 Sejong-ro, Sejong-si 339-700, Republic of Korea.
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Fu H, Yuan J, Gao H. Microbial oxidative stress response: Novel insights from environmental facultative anaerobic bacteria. Arch Biochem Biophys 2015; 584:28-35. [DOI: 10.1016/j.abb.2015.08.012] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 08/19/2015] [Accepted: 08/20/2015] [Indexed: 02/03/2023]
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97
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Molecular mechanism involved in the response to hydrogen peroxide stress in Acinetobacter oleivorans DR1. Appl Microbiol Biotechnol 2015; 99:10611-26. [PMID: 26298700 DOI: 10.1007/s00253-015-6914-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 07/26/2015] [Accepted: 08/03/2015] [Indexed: 10/23/2022]
Abstract
Two-dimensional gel electrophoresis was conducted to investigate the effect of H2O2 on whole protein expression in Acinetobacter oleivorans DR1. Functional classification of 13 upregulated proteins using MALDI-TOF mass spectrometry showed relationships with oxidative stress, energy production and conversion, nucleotide and amino acid metabolism, membrane-related, ion transport, and chaperone-related functions. Alignment of OxyR-binding regions from Pseudomonas aeruginosa and Escherichia coli with promoters of identified proteins revealed that only ahpC, ahpF, and trxB (thioredoxin-disulfide reductase) genes, along with a newly found oprC (putative outer membrane receptor protein) gene, have OxyR-binding sites. The oxyR and ahpC mutants were more sensitive to H2O2 and showed growth defects in both nutritional and n-hexadecane-amended media. Four catalases present in the genome of A. oleivorans DR1 were not detected, which led us to confirm the expression and activity of those catalases in the presence of H2O2. The expression patterns of the four catalase genes differed at different concentrations of H2O2. Interestingly, the promoters of both known OxyR-controlled katG gene (AOLE_17390) and putative small catalase gene (AOLE_09800) have OxyR-binding sites. Gel-shift assay confirmed OxyR binding to the promoter regions of newly identified OxyR-controlled genes encoding OprC and a putative catalase. Hierarchical expression and OxyR-binding of several OxyR-controlled genes suggested that concentration is an important factor in inducing the set of genes under H2O2 stress.
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98
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Shi M, Wan F, Mao Y, Gao H. Unraveling the Mechanism for the Viability Deficiency of Shewanella oneidensis oxyR Null Mutant. J Bacteriol 2015; 197:2179-2189. [PMID: 25897035 PMCID: PMC4455265 DOI: 10.1128/jb.00154-15] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Accepted: 04/16/2015] [Indexed: 01/22/2023] Open
Abstract
UNLABELLED Oxidative stresses triggered by reactive oxygen species (ROS) that damage various cellular components are unavoidable for virtually all living organisms. In defense, microorganisms have evolved sophisticated mechanisms to sense, respond to, and battle against ROS. Shewanella oneidensis, an important research model for applied and environmental microbes, employs OxyR to mediate the response to H2O2 by derepressing the production of the major H2O2 scavenger KatB as a major means toward these goals. Surprisingly, despite enhanced H2O2 degradation, the oxyR mutant carries a viability deficiency phenotype (plating defect), which can be suppressed by the addition of exogenous iron species. Experiments showed that the defect was not due to iron starvation. Rather, multiple lines of evidence suggested that H2O2 generated abiotically in lysogeny broth (LB) is responsible for the defect by quickly killing mutant cells. We then showed that the iron species suppressed the plating defect by two distinct mechanisms, either as an H2O2 scavenger without involving living cells or as an environmental cue to stimulate an OxyR-independent response to help cells cope with oxidative stress. Based on the suppression of the plating defect by overproduction of H2O2 scavengers in vivo, we propose that cellular components that are vulnerable to H2O2 and responsible for the defect may reside outside the cytoplasm. IMPORTANCE In bacteria, OxyR is the major regulator controlling the cellular response to H2O2. The loss of OxyR results in reduced viability in many species, but the underlying mechanism is unknown. We showed in S. oneidensis that this defect was due to H2O2 generated abiotically in LB. We then showed that this defect could be corrected by the addition of Fe(2+) or catalase to the LB or increased intracellular production of catalase. Further analyses revealed that Fe(2+) was able not only to decompose H2O2 directly but also to stimulate the activity of OxyR-independent H2O2-scavenging enzymes. Our data indicate that iron species play a previously underappreciated role in protecting cells from H2O2 in environments.
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Affiliation(s)
- Miaomiao Shi
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- Key Laboratory for Agro-Microbial Research and Utilization, Zhejiang Province, Hangzhou, Zhejiang, China
| | - Fen Wan
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- Key Laboratory for Agro-Microbial Research and Utilization, Zhejiang Province, Hangzhou, Zhejiang, China
| | - Yinting Mao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- Key Laboratory for Agro-Microbial Research and Utilization, Zhejiang Province, Hangzhou, Zhejiang, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- Key Laboratory for Agro-Microbial Research and Utilization, Zhejiang Province, Hangzhou, Zhejiang, China
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99
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Wan F, Mao Y, Dong Y, Ju L, Wu G, Gao H. Impaired cell envelope resulting from arcA mutation largely accounts for enhanced sensitivity to hydrogen peroxide in Shewanella oneidensis. Sci Rep 2015; 5:10228. [PMID: 25975178 PMCID: PMC4432559 DOI: 10.1038/srep10228] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 04/07/2015] [Indexed: 01/06/2023] Open
Abstract
Oxidative stress is one of the major challenges that Shewanella encounter routinely because they thrive in redox-stratified environments prone to reactive oxygen species (ROS) formation, letting alone that ROS can be generated endogenously. As respiration is the predominant process for endogenous ROS, regulators mediating respiration have been demonstrated and/or implicated to play a role in oxidative stress response. In our efforts to unveil the involvement of global regulators for respiration in the oxidative stress response, we found that loss of the Arc system increases S. oneidensis sensitivity to H2O2 whereas neither Fnr nor Crp has a significant role. A comparison of transcriptomic profiles of the wild-type and its isogenic arcA mutant revealed that the OxyR regulon is independent of the Arc system. We then provided evidence that the enhanced H2O2 sensitivity of the arcA mutant is due to an increased H2O2 uptake rate, a result of a cell envelope defect. Although one of three proteases of the ArcA regulon when in excess is partially accountable for the envelope defect, the major contributors remain elusive. Overall, our data indicate that the Arc system influences the bacterial cell envelope biosynthesis, a physiological aspect that has not been associated with the regulator before.
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Affiliation(s)
- Fen Wan
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Yinting Mao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Yangyang Dong
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Lili Ju
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Genfu Wu
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
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Borisov VB, Forte E, Siletsky SA, Arese M, Davletshin AI, Sarti P, Giuffrè A. Cytochrome bd protects bacteria against oxidative and nitrosative stress: A potential target for next-generation antimicrobial agents. BIOCHEMISTRY (MOSCOW) 2015; 80:565-75. [DOI: 10.1134/s0006297915050077] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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