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Yin R, Cheng J, Lin J. The role of the type VI secretion system in the stress resistance of plant-associated bacteria. STRESS BIOLOGY 2024; 4:16. [PMID: 38376647 PMCID: PMC10879055 DOI: 10.1007/s44154-024-00151-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 01/26/2024] [Indexed: 02/21/2024]
Abstract
The type VI secretion system (T6SS) is a powerful bacterial molecular weapon that can inject effector proteins into prokaryotic or eukaryotic cells, thereby participating in the competition between bacteria and improving bacterial environmental adaptability. Although most current studies of the T6SS have focused on animal bacteria, this system is also significant for the adaptation of plant-associated bacteria. This paper briefly introduces the structure and biological functions of the T6SS. We summarize the role of plant-associated bacterial T6SS in adaptability to host plants and the external environment, including resistance to biotic stresses such as host defenses and competition from other bacteria. We review the role of the T6SS in response to abiotic factors such as acid stress, oxidation stress, and osmotic stress. This review provides an important reference for exploring the functions of the T6SS in plant-associated bacteria. In addition, characterizing these anti-stress functions of the T6SS may provide new pathways toward eliminating plant pathogens and controlling agricultural losses.
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Affiliation(s)
- Rui Yin
- Shaanxi Key Laboratory of Chinese Jujube, College of Life Sciences, Yan'an University, Yan'an, 716000, Shaanxi, China
| | - Juanli Cheng
- Shaanxi Key Laboratory of Chinese Jujube, College of Life Sciences, Yan'an University, Yan'an, 716000, Shaanxi, China
| | - Jinshui Lin
- Shaanxi Key Laboratory of Chinese Jujube, College of Life Sciences, Yan'an University, Yan'an, 716000, Shaanxi, China.
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2
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van Hoek ML, Marchesani A, Rawat M. Diverse roles of low-molecular weight thiol GSH in Francisella's virulence, location sensing and GSH-stealing from host. CURRENT RESEARCH IN MICROBIAL SCIENCES 2023; 6:100218. [PMID: 38303966 PMCID: PMC10831187 DOI: 10.1016/j.crmicr.2023.100218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024] Open
Abstract
Low-molecular weight (LMW) thiols, encompassing peptides and small proteins with active cysteine residue(s), are important to bacteria as they are involved in a wide range of redox reactions. They include the tripeptide glutathione (GSH) and the small redox proteins, thioredoxins and glutaredoxins. We review the low MW thiols and related molecules in Francisella species and what role they may play in growth and virulence. Genes for GSH biosynthesis, metabolism and thioredoxins are present in all strains of Francisella, including the fully human-virulent strains. GSH and cysteine (CSH) are the major LMW thiols in Francisella extracts. We explore the potential role of the LMW thiols to overcome the nutritional challenges of intracellular growth (high GSH conditions) as well as the nutritional challenges of planktonic growth (low GSH conditions), and their contribution to Francisella's sensing its environmental location. Francisella may also use GSH as a source of CSH, for which it is auxotrophic. "Glutathione stealing" from the host may be an important part of Francisella's success strategy as a facultative intracellular pathogen both to detect its location and obtain CSH. An understanding of GSH metabolism in Francisella provides insights into the interaction of this pathogen with its host and may reveal additional targets for therapeutic intervention for tularemia infections.
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Affiliation(s)
- Monique L. van Hoek
- School of Systems Biology, George Mason University, Manassas, VA, United States
| | | | - Mamta Rawat
- Biology Department, California State University, Fresno, CA, United States
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3
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Si M, Hu M, Yang M, Peng Z, Li D, Zhao Y. Characterization of oxidative stress-induced cgahp, a gene coding for alkyl hydroperoxide reductase, from industrial importance Corynebacterium glutamicum. Biotechnol Lett 2023; 45:1309-1326. [PMID: 37606753 PMCID: PMC10460364 DOI: 10.1007/s10529-023-03421-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 07/29/2023] [Indexed: 08/23/2023]
Abstract
Alkyl hydroperoxide reductase (Ahp), comprised of four different subunits AhpC, AhpD, AhpE, and AhpF, is a thiol-based antioxidative enzyme with the ability to protect bacteria against oxidative stress. Functionally, AhpC and AhpE considered as peroxidases directly detoxify peroxides, while AhpD and AhpF as oxidoreductases restore oxidized peroxidases to their reduced form. Corynebacterium glutamicum ncgl0877 encodes a putative Ahp with a unique Cys-Pro-Phe-Cys (C-P-G-C) active-site motif, similar with those of the thiol-disulfide oxidoreductases such as thioredoxin (Trx), mycoredoxin-1 (Mrx1) and AhpD. However, its physiological and biochemical functions remain unknown in C. glutamicum. Here, we report that NCgl0877, designated CgAhp, is involved in the protection against organic peroxide (OP) stress. The cgahp-deleted strain is notably more sensitive to OP stress. The cgahp expression is controlled by a MarR-type transcriptional repressor OasR (organic peroxide- and antibiotic-sensing regulator). The physiological role of CgAhp in resistance to OP stresses is corroborated by its induced expression under stresses. Although CgAhp has a weak peroxidase activity toward OP, it mainly supports the OP-scavenging activity of the thiol-dependent peroxidase preferentially linked to the dihydrolipoamide dehydrogenase (Lpd)/dihydrolipoamide succinyltransferase (SucB)/NADH system. The C-P-G-C motif of CgAhp is essential to maintain the reductase activity. In conclusion, our study identifies CgAhp, behaving like AhpD, as a key disulfide oxidoreductase involved in the oxidative stress tolerance and the functional electron donor for peroxidase.
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Affiliation(s)
- Meiru Si
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Mengdie Hu
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Mingfei Yang
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Zhaoxin Peng
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Donghan Li
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Yuying Zhao
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China.
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou, 466001, Henan, China.
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Gómez LA, Molina RE, Soto RI, Flores MR, Coloma-Rivero RF, Montero DA, Oñate ÁA. Unraveling the Role of the Zinc-Dependent Metalloproteinase/HTH-Xre Toxin/Antitoxin (TA) System of Brucella abortus in the Oxidative Stress Response: Insights into the Stress Response and Virulence. Toxins (Basel) 2023; 15:536. [PMID: 37755962 PMCID: PMC10538038 DOI: 10.3390/toxins15090536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/24/2023] [Accepted: 08/28/2023] [Indexed: 09/28/2023] Open
Abstract
Toxin/antitoxin (TA) systems have been scarcely studied in Brucella abortus, the causative agent of brucellosis, which is one of the most prevalent zoonotic diseases worldwide. In this study, the roles of a putative type II TA system composed by a Zinc-dependent metalloproteinase (ZnMP) and a transcriptional regulator HTH-Xre were evaluated. The deletion of the open reading frame (ORF) BAB1_0270, coding for ZnMP, used to produce a mutant strain, allowed us to evaluate the survival and gene expression of B. abortus 2308 under oxidative conditions. Our results showed that the B. abortus mutant strain exhibited a significantly reduced capacity to survive under hydrogen peroxide-induced oxidative stress. Furthermore, this mutant strain showed a decreased expression of genes coding for catalase (katE), alkyl hydroperoxide reductase (ahpC) and transcriptional regulators (oxyR and oxyR-like), as well as genes involved in the general stress response, phyR and rpoE1, when compared to the wild-type strain. These findings suggest that this type II ZnMP/HTH-Xre TA system is required by B. abortus to resist oxidative stress. Additionally, previous evidence has demonstrated that this ZnMP also participates in the acidic stress resistance and virulence of B. abortus 2308. Therefore, we propose a hypothetical regulatory function for this ZnMP/HTH-Xre TA system, providing insight into the stress response and its potential roles in the pathogenesis of B. abortus.
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Affiliation(s)
- Leonardo A Gómez
- Laboratory of Molecular Immunology, Department of Microbiology, Faculty of Biological Sciences, University of Concepción, Concepción 4030000, Chile
| | - Raúl E Molina
- Laboratory of Molecular Immunology, Department of Microbiology, Faculty of Biological Sciences, University of Concepción, Concepción 4030000, Chile
| | - Rodrigo I Soto
- Laboratory of Molecular Immunology, Department of Microbiology, Faculty of Biological Sciences, University of Concepción, Concepción 4030000, Chile
| | - Manuel R Flores
- Laboratory of Molecular Immunology, Department of Microbiology, Faculty of Biological Sciences, University of Concepción, Concepción 4030000, Chile
| | - Roberto F Coloma-Rivero
- Laboratory of Molecular Immunology, Department of Microbiology, Faculty of Biological Sciences, University of Concepción, Concepción 4030000, Chile
| | - David A Montero
- Laboratory of Molecular Immunology, Department of Microbiology, Faculty of Biological Sciences, University of Concepción, Concepción 4030000, Chile
| | - Ángel A Oñate
- Laboratory of Molecular Immunology, Department of Microbiology, Faculty of Biological Sciences, University of Concepción, Concepción 4030000, Chile
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5
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Llorca MG, Martínez-Espinosa RM. Assessment of Haloferax mediterranei Genome in Search of Copper-Molecular Machinery With Potential Applications for Bioremediation. Front Microbiol 2022; 13:895296. [PMID: 35783429 PMCID: PMC9240420 DOI: 10.3389/fmicb.2022.895296] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 05/27/2022] [Indexed: 11/13/2022] Open
Abstract
Heavy metals are essential micronutrients at low concentrations, serving as cofactors for relevant microbial enzymes (i.e., respiratory nitrate and nitrite reductases NADH dehydrogenase-2, amine oxidase, etc.), but they become harmful cellular intoxicants at significant low concentrations compared to other chemical compounds. The increasing need to incorporate bioremediation in the removal of heavy metals and other contaminants from wastewaters has led extremophiles to the spotlight of research. The haloarchaeon Haloferax mediterranei has promising physiological characteristics regarding bioremediation. However, little is known about how haloarchaea manage to resist high concentrations of heavy metals in the environment. The aim of this work is to develop bioinformatics research as the first step for further omics-based studies to shed light on copper metabolism in haloarchaea by analyzing H. mediterranei genome (strain ATCC 33500). To reach this aim, genome and protein databases have been consulted, and copper-related genes have been identified. BLAST analysis has been carried out to find similarities between copper resistance genes described from other microorganisms and H. mediterranei genes. Plausible copper importer genes, genes coding for siderophores, and copper exporters belonging to P1B-type ATPase group have been found apart from genes encoding copper chaperones, metal-responsive transcriptional regulators, and several proteins belonging to the cupredoxin superfamily: nitrite reductase, nitrous oxide reductases, cytochrome c oxidases, multicopper oxidases, and small blue copper proteins from the amicyanin/pseudoazurin families as halocyanins. As the presence of heavy metals causes oxidative stress, genes coding for proteins involved in antioxidant mechanisms have been also explored: thioredoxin, glutaredoxin, peroxiredoxin, catalase, and γ-glutamylcysteine as an analog of glutathione. Bioinformatic-based analysis of H. mediterranei genome has revealed a set of genes involved in copper metabolism that could be of interest for bioremediation purposes. The analysis of genes involved in antioxidative mechanisms against heavy metals makes it possible to infer the capability of H. mediterranei to synthesize inorganic polyphosphate granules against oxidative stress.
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Affiliation(s)
- Marina García Llorca
- Biochemistry and Molecular Biology Division, Department of Agrochemistry and Biochemistry, Faculty of Sciences, University of Alicante, Alicante, Spain
| | - Rosa María Martínez-Espinosa
- Biochemistry and Molecular Biology Division, Department of Agrochemistry and Biochemistry, Faculty of Sciences, University of Alicante, Alicante, Spain
- Multidisciplinary Institute for Environmental Studies “Ramón Margalef”, University of Alicante, Alicante, Spain
- *Correspondence: Rosa María Martínez-Espinosa,
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Dos Santos MC, Tairum CA, Cabrera VIM, Guimarães Cauz AC, Ribeiro LF, Toledo Junior JC, Toyama MH, Lago JHG, Brocchi M, Netto LES, de Oliveira MA. Adenanthin Is an Efficient Inhibitor of Peroxiredoxins from Pathogens, Inhibits Bacterial Growth, and Potentiates Antibiotic Activities. Chem Res Toxicol 2022; 36:570-582. [PMID: 35537067 DOI: 10.1021/acs.chemrestox.2c00049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The emergence and re-emergence of bacterial strains resistant to multiple drugs represent a global health threat, and the search for novel biological targets is a worldwide concern. AhpC are enzymes involved in bacterial redox homeostasis by metabolizing diverse kinds of hydroperoxides. In pathogenic bacteria, AhpC are related to several functions, as some isoforms are characterized as virulence factors. However, no inhibitor has been systematically evaluated to date. Here we show that the natural ent-kaurane Adenanthin (Adn) efficiently inhibits AhpC and molecular interactions were explored by computer assisted simulations. Additionally, Adn interferes with growth and potentializes the effect of antibiotics (kanamycin and PMBN), positioning Adn as a promising compound to treat infections caused by multiresistant bacterial strains.
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Affiliation(s)
- Melina Cardoso Dos Santos
- Instituto de Biociências, Universidade Estadual Paulista, UNESP, São Vicente, São Paulo 11330-900, Brazil
| | - Carlos Abrunhosa Tairum
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo 05508-090, Brazil
| | | | - Ana Carolina Guimarães Cauz
- Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas, UNICAMP, Campinas, São Paulo 13083-862, Brazil
| | - Luiz Fernando Ribeiro
- Instituto de Biociências, Universidade Estadual Paulista, UNESP, São Vicente, São Paulo 11330-900, Brazil
| | - José Carlos Toledo Junior
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo 14040-901, Brazil
| | - Marcos Hikari Toyama
- Instituto de Biociências, Universidade Estadual Paulista, UNESP, São Vicente, São Paulo 11330-900, Brazil
| | - João Henrique Ghilardi Lago
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, São Paulo 09210-580, Brazil
| | - Marcelo Brocchi
- Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas, UNICAMP, Campinas, São Paulo 13083-862, Brazil
| | - Luis Eduardo Soares Netto
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo 05508-090, Brazil
| | - Marcos Antonio de Oliveira
- Instituto de Biociências, Universidade Estadual Paulista, UNESP, São Vicente, São Paulo 11330-900, Brazil
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Liu T, Yang R, Zhou J, Lu X, Yuan Z, Wei X, Guo L. Interactions Between Streptococcus gordonii and Fusobacterium nucleatum Altered Bacterial Transcriptional Profiling and Attenuated the Immune Responses of Macrophages. Front Cell Infect Microbiol 2022; 11:783323. [PMID: 35071038 PMCID: PMC8776643 DOI: 10.3389/fcimb.2021.783323] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 12/15/2021] [Indexed: 12/24/2022] Open
Abstract
Interspecies coaggregation promotes transcriptional changes in oral bacteria, affecting bacterial pathogenicity. Streptococcus gordonii (S. gordonii) and Fusobacterium nucleatum (F. nucleatum) are common oral inhabitants. The present study investigated the transcriptional profiling of S. gordonii and F. nucleatum subsp. polymorphum in response to the dual-species coaggregation using RNA-seq. Macrophages were infected with both species to explore the influence of bacterial coaggregation on both species' abilities to survive within macrophages and induce inflammatory responses. Results indicated that, after the 30-min dual-species coaggregation, 116 genes were significantly up-regulated, and 151 genes were significantly down-regulated in S. gordonii; 97 genes were significantly down-regulated, and 114 genes were significantly up-regulated in F. nucleatum subsp. polymorphum. Multiple S. gordonii genes were involved in the biosynthesis and export of cell-wall proteins and carbohydrate metabolism. F. nucleatum subsp. polymorphum genes were mostly associated with translation and protein export. The coaggregation led to decreased expression levels of genes associated with lipopolysaccharide and peptidoglycan biosynthesis. Coaggregation between S. gordonii and F. nucleatum subsp. polymorphum significantly promoted both species' intracellular survival within macrophages and attenuated the production of pro-inflammatory cytokines IL-6 and IL-1β. Physical interactions between these two species promoted a symbiotic lifestyle and repressed macrophage's killing and pro-inflammatory responses.
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Affiliation(s)
- Tingjun Liu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Ruiqi Yang
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Jiani Zhou
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Xianjun Lu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Zijian Yuan
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Xi Wei
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Lihong Guo
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
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8
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Tzipilevich E, Russ D, Dangl JL, Benfey PN. Plant immune system activation is necessary for efficient root colonization by auxin-secreting beneficial bacteria. Cell Host Microbe 2021; 29:1507-1520.e4. [PMID: 34610294 DOI: 10.1016/j.chom.2021.09.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 07/07/2021] [Accepted: 08/24/2021] [Indexed: 12/13/2022]
Abstract
Although plant roots encounter a plethora of microorganisms in the surrounding soil, at the rhizosphere, plants exert selective forces on their bacterial colonizers. Unlike immune recognition of pathogenic bacteria, the mechanisms by which beneficial bacteria are selected and how they interact with the plant immune system are not well understood. To better understand this process, we studied the interaction of auxin-producing Bacillus velezensis FZB42 with Arabidopsis roots and found that activation of the plant immune system is necessary for efficient bacterial colonization and auxin secretion. A feedback loop is established in which bacterial colonization triggers an immune reaction and production of reactive oxygen species, which, in turn, stimulate auxin production by the bacteria. Auxin promotes bacterial survival and efficient root colonization, allowing the bacteria to inhibit fungal infection and promote plant health. Thus, a feedback loop between bacteria and the plant immune system promotes the fitness of both partners.
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Affiliation(s)
- Elhanan Tzipilevich
- Department of Biology, Duke University, Durham, NC 27708, USA; Howard Hughes Medical Institute Duke University, Durham, NC 27708, USA
| | - Dor Russ
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Howard Hughes Medical Institute. University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jeffery L Dangl
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Howard Hughes Medical Institute. University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Philip N Benfey
- Department of Biology, Duke University, Durham, NC 27708, USA; Howard Hughes Medical Institute Duke University, Durham, NC 27708, USA.
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9
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Gibson JF, Pidwill GR, Carnell OT, Surewaard BGJ, Shamarina D, Sutton JAF, Jeffery C, Derré-Bobillot A, Archambaud C, Siggins MK, Pollitt EJG, Johnston SA, Serror P, Sriskandan S, Renshaw SA, Foster SJ. Commensal bacteria augment Staphylococcus aureus infection by inactivation of phagocyte-derived reactive oxygen species. PLoS Pathog 2021; 17:e1009880. [PMID: 34529737 PMCID: PMC8478205 DOI: 10.1371/journal.ppat.1009880] [Citation(s) in RCA: 7] [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: 06/14/2021] [Revised: 09/28/2021] [Accepted: 08/09/2021] [Indexed: 12/22/2022] Open
Abstract
Staphylococcus aureus is a human commensal organism and opportunist pathogen, causing potentially fatal disease. The presence of non-pathogenic microflora or their components, at the point of infection, dramatically increases S. aureus pathogenicity, a process termed augmentation. Augmentation is associated with macrophage interaction but by a hitherto unknown mechanism. Here, we demonstrate a breadth of cross-kingdom microorganisms can augment S. aureus disease and that pathogenesis of Enterococcus faecalis can also be augmented. Co-administration of augmenting material also forms an efficacious vaccine model for S. aureus. In vitro, augmenting material protects S. aureus directly from reactive oxygen species (ROS), which correlates with in vivo studies where augmentation restores full virulence to the ROS-susceptible, attenuated mutant katA ahpC. At the cellular level, augmentation increases bacterial survival within macrophages via amelioration of ROS, leading to proliferation and escape. We have defined the molecular basis for augmentation that represents an important aspect of the initiation of infection. S. aureus is a commensal inhabitant of the human skin and nares. However, it can cause serious diseases if it is able to breach our protective barriers such as the skin, often via wounds or surgery. If infection occurs via a wound, this initial inoculum contains both the pathogen, other members of the microflora and also wider environmental microbes. We have previously described “augmentation”, whereby this other non-pathogenic material can enhance the ability of S. aureus to lead to a serious disease outcome. Here we have determined the breadth of augmenting material and elucidated the cellular and molecular basis for its activity. Augmentation occurs via shielding of S. aureus from the direct bactericidal effects of reactive oxygen species produced by macrophages. This initial protection enables the effective establishment of S. aureus infection. Understanding augmentation not only explains an important facet of the interaction of S. aureus with our innate immune system, but also provides a platform for the development of novel prophylaxis approaches.
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Affiliation(s)
- Josie F. Gibson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
- Florey Institute, University of Sheffield, Sheffield, United Kingdom, Sheffield, United Kingdom
- The Bateson Centre, University of Sheffield, Sheffield, United Kingdom
| | - Grace R. Pidwill
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
- Florey Institute, University of Sheffield, Sheffield, United Kingdom, Sheffield, United Kingdom
| | - Oliver T. Carnell
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
- Florey Institute, University of Sheffield, Sheffield, United Kingdom, Sheffield, United Kingdom
| | - Bas G. J. Surewaard
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Daria Shamarina
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
- Florey Institute, University of Sheffield, Sheffield, United Kingdom, Sheffield, United Kingdom
| | - Joshua A. F. Sutton
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
- Florey Institute, University of Sheffield, Sheffield, United Kingdom, Sheffield, United Kingdom
| | - Charlotte Jeffery
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | | | - Cristel Archambaud
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Matthew K. Siggins
- Department of Infectious Disease, Imperial College London, London, United Kingdom
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Eric J. G. Pollitt
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
- Florey Institute, University of Sheffield, Sheffield, United Kingdom, Sheffield, United Kingdom
| | - Simon A. Johnston
- Florey Institute, University of Sheffield, Sheffield, United Kingdom, Sheffield, United Kingdom
- The Bateson Centre, University of Sheffield, Sheffield, United Kingdom
- Department of Infection, Immunity and Cardiovascular disease, Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Pascale Serror
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Shiranee Sriskandan
- Department of Infectious Disease, Imperial College London, London, United Kingdom
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Stephen A. Renshaw
- Florey Institute, University of Sheffield, Sheffield, United Kingdom, Sheffield, United Kingdom
- The Bateson Centre, University of Sheffield, Sheffield, United Kingdom
- Department of Infection, Immunity and Cardiovascular disease, Medical School, University of Sheffield, Sheffield, United Kingdom
- * E-mail: (SAR); (SJF)
| | - Simon J. Foster
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
- Florey Institute, University of Sheffield, Sheffield, United Kingdom, Sheffield, United Kingdom
- * E-mail: (SAR); (SJF)
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10
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Wan F, Feng X, Yin J, Gao H. Distinct H 2O 2-Scavenging System in Yersinia pseudotuberculosis: KatG and AhpC Act Together to Scavenge Endogenous Hydrogen Peroxide. Front Microbiol 2021; 12:626874. [PMID: 34025596 PMCID: PMC8139631 DOI: 10.3389/fmicb.2021.626874] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 03/22/2021] [Indexed: 01/09/2023] Open
Abstract
To colonize in the digestive tract of animals and humans, Yersinia pseudotuberculosis has to deal with reactive oxygen species (ROS) produced by host cells and microbiota. However, an understanding of the ROS-scavenging systems and their regulation in this bacterium remains largely elusive. In this study, we identified OxyR as the master transcriptional regulator mediating cellular responses to hydrogen peroxide (H2O2) in Y. pseudotuberculosis through genomics and transcriptomics analyses. OxyR activates transcription of diverse genes, especially the core members of its regulon, including those encoding catalases, peroxidases, and thiol reductases. The data also suggest that sulfur species and manganese may play a particular role in the oxidative stress response of Y. pseudotuberculosis. Among the three H2O2-scavenging systems in Y. pseudotuberculosis, catalase/peroxidase KatE functions as the primary scavenger for high levels of H2O2; NADH peroxidase alkyl hydroperoxide reductase (AhpR) and catalase KatG together are responsible for removing low levels of H2O2. The simultaneous loss of both AhpC (the peroxidatic component of AhpR) and KatG results in activation of OxyR. Moreover, we found that AhpC, unlike its well-characterized Escherichia coli counterpart, has little effect on protecting cells against toxicity of organic peroxides. These findings provide not only novel insights into the structural and functional diversity of bacterial H2O2-scavenging systems but also a basic understanding of how Y. pseudotuberculosis copes with oxidative stress.
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Affiliation(s)
- Fen Wan
- College of Laboratory Medicine, Hangzhou Medical College, Hangzhou, China
| | - Xue Feng
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jianhua Yin
- College of Biotechnology and Bioengineering, Zhenjiang University of Technology, Hangzhou, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, China
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11
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Beier N, Kucklick M, Fuchs S, Mustafayeva A, Behringer M, Härtig E, Jahn D, Engelmann S. Adaptation of Dinoroseobacter shibae to oxidative stress and the specific role of RirA. PLoS One 2021; 16:e0248865. [PMID: 33780465 PMCID: PMC8007024 DOI: 10.1371/journal.pone.0248865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 03/05/2021] [Indexed: 11/23/2022] Open
Abstract
Dinoroseobacter shibae living in the photic zone of marine ecosystems is frequently exposed to oxygen that forms highly reactive species. Here, we analysed the adaptation of D. shibae to different kinds of oxidative stress using a GeLC-MS/MS approach. D. shibae was grown in artificial seawater medium in the dark with succinate as sole carbon source and exposed to hydrogen peroxide, paraquat or diamide. We quantified 2580 D. shibae proteins. 75 proteins changed significantly in response to peroxide stress, while 220 and 207 proteins were differently regulated by superoxide stress and thiol stress. As expected, proteins like thioredoxin and peroxiredoxin were among these proteins. In addition, proteins involved in bacteriochlophyll biosynthesis were repressed under disulfide and superoxide stress but not under peroxide stress. In contrast, proteins associated with iron transport accumulated in response to peroxide and superoxide stress. Interestingly, the iron-responsive regulator RirA in D. shibae was downregulated by all stressors. A rirA deletion mutant showed an improved adaptation to peroxide stress suggesting that RirA dependent proteins are associated with oxidative stress resistance. Altogether, 139 proteins were upregulated in the mutant strain. Among them are proteins associated with protection and repair of DNA and proteins (e. g. ClpB, Hsp20, RecA, and a thioredoxin like protein). Strikingly, most of the proteins involved in iron metabolism such as iron binding proteins and transporters were not part of the upregulated proteins. In fact, rirA deficient cells were lacking a peroxide dependent induction of these proteins that may also contribute to a higher cell viability under these conditions.
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Affiliation(s)
- Nicole Beier
- Institute for Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
- Microbial Proteomics, Helmholtzzentrum für Infektionsforschung, Braunschweig, Germany
| | - Martin Kucklick
- Institute for Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
- Microbial Proteomics, Helmholtzzentrum für Infektionsforschung, Braunschweig, Germany
| | | | - Ayten Mustafayeva
- Institute for Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
- Microbial Proteomics, Helmholtzzentrum für Infektionsforschung, Braunschweig, Germany
| | - Maren Behringer
- Institute for Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Elisabeth Härtig
- Institute for Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Dieter Jahn
- Institute for Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
- Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
| | - Susanne Engelmann
- Institute for Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
- Microbial Proteomics, Helmholtzzentrum für Infektionsforschung, Braunschweig, Germany
- Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
- * E-mail:
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12
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Jin X, Chen D, Wu F, Zhang L, Huang Y, Lin Z, Wang X, Wang R, Xu L, Chen Y. Hydrogen Sulfide Protects Against Ammonia-Induced Neurotoxicity Through Activation of Nrf2/ARE Signaling in Astrocytic Model of Hepatic Encephalopathy. Front Cell Neurosci 2020; 14:573422. [PMID: 33192318 PMCID: PMC7642620 DOI: 10.3389/fncel.2020.573422] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 09/15/2020] [Indexed: 12/13/2022] Open
Abstract
Objective: Hepatic encephalopathy (HE) characterized by neuropsychiatric abnormalities is a major complication of cirrhosis with high mortality. However, the pathogenesis of HE has not been fully elucidated. This study aimed to determine endogenous hydrogen sulfide (H2S) in the blood of HE patients and investigate the role of H2S in an astrocytic model of HE. Methods: Patients with and without HE were recruited to determine plasma H2S levels and blood microbial 16S rRNA gene. Rat astrocytes were employed as a model of HE by treatment of NH4Cl. Exogenous H2S was preadded. Cell viability was measured by Cell Counting Kit-8 (CCK-8) assay, and cell death was evaluated by lactate dehydrogenase (LDH) release. Apoptosis was determined by Hoechst 33342/Propidium Iodide (PI) Double Staining and Western blot analysis of apoptosis-related protein expression. Intracellular reactive oxygen species (ROS) levels were assessed by flow cytometer. Expressions of Nrf2 and its downstream regulated genes were examined by immunofluorescence staining and Western blot, respectively. Nrf2 gene knockdown was performed by antisense shRNA of Nrf2 gene. Results: There was a significant decrease in H2S levels in cirrhotic patients with HE compared with without HE. Blood microbiota analyses revealed that certain strains associated with H2S production were negatively correlated with HE. In vitro, H2S markedly attenuated NH4Cl-induced cytotoxicity, oxidative stress, and apoptosis. This effect was mediated by Nrf2/ARE signaling, and knockdown of Nrf2 expression abolished the antagonistic effect of H2S on NH4Cl-induced neurotoxicity in astrocytes. Conclusion: Levels of H2S and bacteria associated with H2S production are decreased in HE, and H2S functions as the neuroprotector against NH4Cl-induced HE by activating Nrf2/ARE signaling of astrocytes.
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Affiliation(s)
- Xiaozhi Jin
- Department of Infectious Diseases, Wenzhou Key Laboratory of Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Hepatology Institute of Wenzhou Medical University, Zhejiang Provincial Key Laboratory for Accurate Diagnosis and Treatment of Chronic Liver Diseases, Wenzhou, China
| | - Dazhi Chen
- Department of Gastroenterology, The First Hospital of Peking University, Beijing, China
| | - Faling Wu
- Department of Infectious Diseases, Wenzhou Key Laboratory of Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Hepatology Institute of Wenzhou Medical University, Zhejiang Provincial Key Laboratory for Accurate Diagnosis and Treatment of Chronic Liver Diseases, Wenzhou, China
| | - Lei Zhang
- Department of Infectious Diseases, Wenzhou Key Laboratory of Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Hepatology Institute of Wenzhou Medical University, Zhejiang Provincial Key Laboratory for Accurate Diagnosis and Treatment of Chronic Liver Diseases, Wenzhou, China
| | - Yu Huang
- Department of Infectious Diseases, Wenzhou Key Laboratory of Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Hepatology Institute of Wenzhou Medical University, Zhejiang Provincial Key Laboratory for Accurate Diagnosis and Treatment of Chronic Liver Diseases, Wenzhou, China
| | - Zhuo Lin
- Department of Infectious Diseases, Wenzhou Key Laboratory of Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Hepatology Institute of Wenzhou Medical University, Zhejiang Provincial Key Laboratory for Accurate Diagnosis and Treatment of Chronic Liver Diseases, Wenzhou, China
| | - Xiaodong Wang
- Department of Infectious Diseases, Wenzhou Key Laboratory of Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Hepatology Institute of Wenzhou Medical University, Zhejiang Provincial Key Laboratory for Accurate Diagnosis and Treatment of Chronic Liver Diseases, Wenzhou, China
| | - Rui Wang
- Department of Infectious Diseases, Wenzhou Key Laboratory of Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Hepatology Institute of Wenzhou Medical University, Zhejiang Provincial Key Laboratory for Accurate Diagnosis and Treatment of Chronic Liver Diseases, Wenzhou, China
| | - Lanman Xu
- Department of Infectious Diseases and Liver Diseases, Ningbo Medical Center Lihuili Hospital, Ningbo, China.,Department of Infectious Diseases and Liver Diseases, The Affiliated Lihuili Hospital of Ningbo University, Ningbo, China
| | - Yongping Chen
- Department of Infectious Diseases, Wenzhou Key Laboratory of Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Hepatology Institute of Wenzhou Medical University, Zhejiang Provincial Key Laboratory for Accurate Diagnosis and Treatment of Chronic Liver Diseases, Wenzhou, China
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13
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Chong SMS, Kamariah N, Grüber G. Residues of helix ɑ2 are critical for catalytic efficiency of mycobacterial alkylhydroperoxide reductase subunit C. FEBS Lett 2020; 594:2829-2839. [PMID: 32557576 DOI: 10.1002/1873-3468.13864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/28/2020] [Accepted: 05/29/2020] [Indexed: 11/05/2022]
Abstract
The ability of Mycobacteria to overcome oxidative stress is of paramount importance for its survival within the host. One of the key enzymes that are involved in protecting the bacterium from reactive oxygen species is the catalase-peroxidase (KatG). However, in strains resistant to the antibiotic isoniazid, KatG is rendered ineffective, which is associated with an increased expression of alkylhydroperoxide reductase subunit C (AhpC). Mycobacterial AhpC possesses a unique helical displacement when compared to its bacterial counterparts. Here, via mutagenesis studies, we demonstrate the importance of this helix for redox modulation of the catalytic activity of AhpC. Along with structural insights from crystallographic data, the impact of critical residues on the structure and flexibility of the helix and on AhpC oligomerization is described.
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Affiliation(s)
- Shi Min Sherilyn Chong
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore.,School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Republic of Singapore.,Nanyang Institute of Technology in Health and Medicine, Interdisciplinary Graduate School, Nanyang Technological University, Singapore, Republic of Singapore
| | - Neelagandan Kamariah
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
| | - Gerhard Grüber
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
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14
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Feng X, Guo K, Gao H. Plasticity of the peroxidase AhpC links multiple substrates to diverse disulfide-reducing pathways in Shewanella oneidensis. J Biol Chem 2020; 295:11118-11130. [PMID: 32532818 DOI: 10.1074/jbc.ra120.014010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 05/29/2020] [Indexed: 12/25/2022] Open
Abstract
AhpC is a bacterial representative of 2-Cys peroxiredoxins (Prxs) with broad substrate specificity and functional plasticity. However, details underpinning these two important attributes of AhpC remain unclear. Here, we studied the functions and mechanisms of regulation of AhpC in the facultative Gram-negative anaerobic bacterium Shewanella oneidensis, in which AhpC's physiological roles can be conveniently assessed through its suppression of a plating defect due to the genetic loss of a major catalase. We show that successful suppression can be achieved only when AhpC is produced in a dose- and time-dependent manner through a complex mechanism involving activation of the transcriptional regulator OxyR, transcription attenuation, and translation reduction. By analyzing AhpC truncation variants, we demonstrate that reactivity with organic peroxides (OPs) rather than H2O2 is resilient to mutagenesis, implying that OP reduction is the core catalytic function of AhpC. Intact AhpC could be recycled only by its cognate reductase AhpF, and AhpC variants lacking the Prx domain or the extreme C-terminal five residues became promiscuous electron acceptors from the thioredoxin reductase TrxR and the GSH reductase Gor in addition to AhpF, implicating an additional dimension to functional plasticity of AhpC. Finally, we show that the activity of S. oneidensis AhpC is less affected by mutations than that of its Escherichia coli counterpart. These findings suggest that the physiological roles of bacterial AhpCs are adapted to different oxidative challenges, depending on the organism, and that its functional plasticity is even more extensive than previously reported.
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Affiliation(s)
- Xue Feng
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Kailun Guo
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Haichun Gao
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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15
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Khademian M, Imlay JA. Do reactive oxygen species or does oxygen itself confer obligate anaerobiosis? The case of Bacteroides thetaiotaomicron. Mol Microbiol 2020; 114:333-347. [PMID: 32301184 DOI: 10.1111/mmi.14516] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/07/2020] [Accepted: 04/07/2020] [Indexed: 02/06/2023]
Abstract
Bacteroides thetaiotaomicron was examined to determine whether its obligate anaerobiosis is imposed by endogenous reactive oxygen species or by molecular oxygen itself. Previous analyses established that aerated B. thetaiotaomicron loses some enzyme activities due to a high rate of endogenous superoxide formation. However, the present study establishes that another key step in central metabolism is poisoned by molecular oxygen itself. Pyruvate dissimilation was shown to depend upon two enzymes, pyruvate:formate lyase (PFL) and pyruvate:ferredoxin oxidoreductase (PFOR), that lose activity upon aeration. PFL is a glycyl-radical enzyme whose vulnerability to oxygen is already understood. The rate of PFOR damage was unaffected by the level of superoxide or peroxide, showing that molecular oxygen itself is the culprit. The cell cannot repair PFOR, which amplifies the impact of damage. The rates of PFOR and fumarase inactivation are similar, suggesting that superoxide dismutase is calibrated so the oxygen- and superoxide-sensitive enzymes are equally sensitive to aeration. The physiological purpose of PFL and PFOR is to degrade pyruvate without disrupting the redox balance, and they do so using catalytic mechanisms that are intrinsically vulnerable to oxygen. In this way, the anaerobic excellence and oxygen sensitivity of B. thetaiotaomicron are two sides of the same coin.
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Affiliation(s)
- Maryam Khademian
- Department of Microbiology, University of Illinois, Urbana, IL, USA
| | - James A Imlay
- Department of Microbiology, University of Illinois, Urbana, IL, USA
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16
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Liang L, Haltli B, Marchbank DH, Fischer M, Kirby CW, Correa H, Clark TN, Gray CA, Kerr RG. Discovery of an Isothiazolinone-Containing Antitubercular Natural Product Levesquamide. J Org Chem 2020; 85:6450-6462. [PMID: 32363877 DOI: 10.1021/acs.joc.0c00339] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Antitubercular agent levesquamide is a new polyketide-nonribosomal peptide (PK-NRP) hybrid marine natural product isolated from Streptomyces sp. RKND-216. The structure contains a rare isothiazolinone moiety which has only been reported in collismycin SN. Structure elucidation by NMR spectroscopy was a significant challenge due to a deficiency of protons in this aromatic moiety. Therefore, the genome of Streptomyces sp. RKND-216 was sequenced to identify the levesquamide biosynthetic gene cluster (BGC). Analysis of the BGC provided structural insights and guided stable-isotope labeling experiments, which led to the assignment of the fused pyridine-isothiazolinone moiety. The BGC and the labeling experiments provide further insights into the biosynthetic origin of isothiazolinones. Levesquamide exhibited antimicrobial activity in the microplate alamarBlue assay (MABA) and low oxygen recovery assay (LORA) against Mycobacterium tuberculosis H37Rv with minimum inhibitory concentration (MIC) values of 9.65 and 22.28 μM, respectively. Similar activity was exhibited against rifampicin- and isoniazid-resistant M. tuberculosis strains with MIC values of 9.46 and 9.90 μM, respectively. This result suggests levesquamide has a different mode of action against M. tuberculosis compared to the two first-line antitubercular drugs rifampicin and isoniazid. Furthermore, levesquamide shows no cytotoxicity against the Vero cell line, suggesting it may have a useful therapeutic window.
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Affiliation(s)
| | - Bradley Haltli
- Nautilus Biosciences Croda, 550 University Avenue, Regis and Joan Duffy Research Centre, Charlottetown, PE C1A 4P3, Canada
| | - Douglas H Marchbank
- Nautilus Biosciences Croda, 550 University Avenue, Regis and Joan Duffy Research Centre, Charlottetown, PE C1A 4P3, Canada
| | - Maike Fischer
- Charlottetown Research & Development Centre, Agriculture and Agri-Food Canada, 440 University Avenue, Charlottetown, PE C1A 4N6, Canada
| | - Christopher W Kirby
- Charlottetown Research & Development Centre, Agriculture and Agri-Food Canada, 440 University Avenue, Charlottetown, PE C1A 4N6, Canada
| | - Hebelin Correa
- Nautilus Biosciences Croda, 550 University Avenue, Regis and Joan Duffy Research Centre, Charlottetown, PE C1A 4P3, Canada
| | - Trevor N Clark
- Department of Chemistry, University of New Brunswick, 30 Dineen Drive, Fredericton, NB E3B 5A3, Canada
| | - Christopher A Gray
- Department of Chemistry, University of New Brunswick, 30 Dineen Drive, Fredericton, NB E3B 5A3, Canada.,Department of Biological Sciences, University of New Brunswick, 100 Tucker Park Road, Saint John, NB E2L 4L5, Canada
| | - Russell G Kerr
- Nautilus Biosciences Croda, 550 University Avenue, Regis and Joan Duffy Research Centre, Charlottetown, PE C1A 4P3, Canada
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17
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Li LH, Shih YL, Huang JY, Wu CJ, Huang YW, Huang HH, Tsai YC, Yang TC. Protection from hydrogen peroxide stress relies mainly on AhpCF and KatA2 in Stenotrophomonas maltophilia. J Biomed Sci 2020; 27:37. [PMID: 32093695 PMCID: PMC7041247 DOI: 10.1186/s12929-020-00631-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 02/17/2020] [Indexed: 11/10/2022] Open
Abstract
Background Aerobically-grown bacteria can be challenged by hydrogen peroxide stress from endogenous aerobic metabolism and exogenously generated reactive oxygen species. Catalase (Kat), alkyl hydroperoxidase (Ahp), and glutathione peroxidase (Gpx) systems are major adaptive responses to H2O2 stress in bacteria. Stenotrophomonas maltophilia is a ubiquitous Gram-negative bacterium equipped with four Kats (KatA1, KatA2, KatMn, and KatE), one Ahp (AhpCF), and three Gpxs (Gpx1, Gpx2, and Gpx3). Here, we systematically investigated how the eight H2O2 scavenging genes differentially contribute to the low-micromolar levels of H2O2 generated from aerobic metabolism and high-millimolar levels of H2O2 from exogenous sources. Methods Gene expression was assessed and quantified by reverse transcription-PCR (RT-PCR) and real time quantitative PCR (qRT-PCR), respectively. The contribution of these enzymes to H2O2 stress was assessed using mutant construction and functional investigation. Results Of the eight genes, katA2, ahpCF, and gpx3 were intrinsically expressed in response to low-micromolar levels of H2O2 from aerobic metabolism, and the expression of katA2 and ahpCF was regulated by OxyR. AhpCF and KatA2 were responsible for alleviating aerobic growth-mediated low concentration H2O2 stress and AhpCF played a critical role for stationary-phase cells. KatA2 was upregulated to compensate for AhpCF in the case of ahpCF inactivation. After exposure to millimolar levels of H2O2, katA2 and ahpCF were upregulated in an OxyR-dependent manner. KatA2 was the critical enzyme for dealing with high concentration H2O2. Loss-of-function of KatA2 increased bacterial susceptibility to high concentration H2O2. Conclusions AhpCF and KatA2 are key enzymes protecting S. maltophilia from hydrogen peroxide stress.
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Affiliation(s)
- Li-Hua Li
- Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Program of Medical Biotechnology, Taipei Medical University, Taipei, Taiwan
| | - Yung-Luen Shih
- Department of Pathology and Laboratory Medicine, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.,School of Medical Laboratory Science and Biotechnology, Taipei Medical University, Taipei, Taiwan.,School of Medicine, College of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan
| | - Jing-Yun Huang
- Department of Laboratory Medicine, Chang-Gung Memorial Hospital, LinKou, Taiwan.,Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Chao-Jung Wu
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yi-Wei Huang
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Hsin-Hui Huang
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yu-Chieh Tsai
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Tsuey-Ching Yang
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan.
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18
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Vazquez DS, Zeida A, Agudelo WA, Montes MR, Ferrer-Sueta G, Santos J. Exploring the conformational transition between the fully folded and locally unfolded substates of Escherichia coli thiol peroxidase. Phys Chem Chem Phys 2020; 22:9518-9533. [DOI: 10.1039/d0cp00140f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Temporal acquisition of the fully folded conformational substate of the Escherichia coli thiol peroxidase by accelerated molecular dynamics simulations.
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Affiliation(s)
- Diego S. Vazquez
- Laboratorio de Expresión y Plegado de Proteínas
- Departamento de Ciencia y Tecnología
- Universidad Nacional de Quilmes
- Buenos Aires
- Argentina
| | - Ari Zeida
- Departamento de Bioquímica y Centro de Investigaciones Biomédicas (CEINBIO)
- Facultad de Medicina
- Universidad de la República
- Montevideo
- Uruguay
| | - William A. Agudelo
- Fundación Instituto de Inmunología de Colombia (FIDIC)
- Bogotá D.C
- Colombia
| | - Mónica R. Montes
- Instituto de Química y Fisicoquímica Biológicas (IQUIFIB)
- “Prof. Dr Alejandro C. Paladini”
- Universidad de Buenos Aires and CONICET
- Ciudad Autónoma de Buenos Aires
- Argentina
| | - Gerardo Ferrer-Sueta
- Laboratorio de Fisicoquímica Biológica
- Instituto de Química Biológica and CEINBIO
- Facultad de Ciencias
- Universidad de la República
- Montevideo
| | - Javier Santos
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
- Ciudad Autónoma de Buenos Aires
- Argentina
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3)
- Departamento de Fisiología y Biología Molecular y Celular
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19
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Molecular Mechanisms That Define Redox Balance Function in Pathogen-Host Interactions-Is There a Role for Dietary Bioactive Polyphenols? Int J Mol Sci 2019; 20:ijms20246222. [PMID: 31835548 PMCID: PMC6940965 DOI: 10.3390/ijms20246222] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/02/2019] [Accepted: 12/03/2019] [Indexed: 01/01/2023] Open
Abstract
To ensure a functional immune system, the mammalian host must detect and respond to the presence of pathogenic bacteria during infection. This is accomplished in part by generating reactive oxygen species (ROS) that target invading bacteria; a process that is facilitated by NADPH oxidase upregulation. Thus, bacterial pathogens must overcome the oxidative burst produced by the host innate immune cells in order to survive and proliferate. In this way, pathogenic bacteria develop virulence, which is related to the affinity to secrete effector proteins against host ROS in order to facilitate microbial survival in the host cell. These effectors scavenge the host generated ROS directly, or alternatively, manipulate host cell signaling mechanisms designed to benefit pathogen survival. The redox-balance of the host is important for the regulation of cell signaling activities that include mitogen-activated protein kinase (MAPK), p21-activated kinase (PAK), phosphatidylinositol 3-kinase (PI3K)/Akt, and nuclear factor κB (NF-κB) pathways. An understanding of the function of pathogenic effectors to divert host cell signaling is important to ascertain the mechanisms underlying pathogen virulence and the eventual host–pathogen relationship. Herein, we examine the effectors produced by the microbial secretion system, placing emphasis on how they target molecular signaling mechanisms involved in a host immune response. Moreover, we discuss the potential impact of bioactive polyphenols in modulating these molecular interactions that will ultimately influence pathogen virulence.
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20
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Aljannat MAK, Oldfield NJ, Albasri HM, Dorrington LKG, Ohri RL, Wooldridge KG, Turner DPJ. The moonlighting peroxiredoxin-glutaredoxin in Neisseria meningitidis binds plasminogen via a C-terminal lysine residue and contributes to survival in a whole blood model. Microb Pathog 2019; 139:103890. [PMID: 31765768 DOI: 10.1016/j.micpath.2019.103890] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 11/20/2019] [Accepted: 11/22/2019] [Indexed: 01/24/2023]
Abstract
Neisseria meningitidis is a human-restricted bacterium that can invade the bloodstream and cross the blood-brain barrier resulting in life-threatening sepsis and meningitis. Meningococci express a cytoplasmic peroxiredoxin-glutaredoxin (Prx5-Grx) hybrid protein that has also been identified on the bacterial surface. Here, recombinant Prx5-Grx was confirmed as a plasminogen (Plg)-binding protein, in an interaction which could be inhibited by the lysine analogue ε-aminocapronic acid. rPrx5-Grx derivatives bearing a substituted C-terminal lysine residue (rPrx5-GrxK244A), but not the active site cysteine residue (rPrx5-GrxC185A) or the sub-terminal rPrx5-GrxK230A lysine residue, exhibited significantly reduced Plg-binding. The absence of Prx5-Grx did not significantly reduce the ability of whole meningococcal cells to bind Plg, but under hydrogen peroxide-mediated oxidative stress, the N. meningitidis Δpxn5-grx mutant survived significantly better than the wild-type or complemented strains. Significantly, using human whole blood as a model of meningococcal bacteremia, it was found that the N. meningitidis Δpxn5-grx mutant had a survival defect compared with the parental or complemented strain, confirming an important role for Prx5-Grx in meningococcal pathogenesis.
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Affiliation(s)
- Mahab A K Aljannat
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Neil J Oldfield
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Hibah M Albasri
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | | | - Radhica L Ohri
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Karl G Wooldridge
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - David P J Turner
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK.
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21
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Jiang G, Yang J, Li X, Cao Y, Liu X, Ling J, Wang H, Zhong Z, Zhu J. Alkyl hydroperoxide reductase is important for oxidative stress resistance and symbiosis in Azorhizobium caulinodans. FEMS Microbiol Lett 2019; 366:5290313. [PMID: 30657885 DOI: 10.1093/femsle/fnz014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 01/15/2019] [Indexed: 11/13/2022] Open
Abstract
Reactive oxygen species (ROS) are not only toxic products of oxygen from aerobic metabolism or stress but also signalling molecules involved in the development of the legume-Rhizobium symbiosis. To assess the importance of alkyl hydroperoxide reductase (AhpCD) in the nitrogen-fixating bacterium Azorhizobium caulinodans, we investigated the phenotypes of the ∆ahpCD strain with regards to ROS resistance and symbiotic interactions with Sesbania rostrata. The ∆ahpCD strain was notably more sensitive than its parent strain to hydrogen peroxide (H2O2) but not to two organic peroxides, in the early log phase. The expression of ahpCD was not controlled by a LysR-type transcriptional activator either in vitro or in vivo. The catalase activity of the ∆ahpCD strain was affected at a relatively low level of H2O2 stress. Furthermore, the ∆ahpCD strain induced a reduced number of stem nodules in S. rostrata with lowering of nitrogenase activity. These data suggest that A. caulinodans AhpCD is not only important for H2O2 detoxification in vitro but also critical for symbiosis with S. rostrata. Functional analysis of AhpCD is worth investigating in other rhizobia to gain a comprehensive view of its contributions to ROS defence and symbiotic association with legumes.
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Affiliation(s)
- Gaofei Jiang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Centre for Solid Organic Waste Resource Utilization, National Engineering Research Centre for Organic-based Fertilizers, Postdoctoral Station of Agricultural Resources and Environment, Nanjing Agricultural University, 210095, Nanjing, PR China
| | - Juan Yang
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, PR China
| | - Xingjuan Li
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, PR China
| | - Yajun Cao
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, PR China
| | - Xiaomeng Liu
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, PR China
| | - Jun Ling
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, PR China
| | - Hui Wang
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, PR China
| | - Zengtao Zhong
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, PR China
| | - Jun Zhu
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, PR China
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Adaptation to Adversity: the Intermingling of Stress Tolerance and Pathogenesis in Enterococci. Microbiol Mol Biol Rev 2019; 83:83/3/e00008-19. [PMID: 31315902 DOI: 10.1128/mmbr.00008-19] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Enterococcus is a diverse and rugged genus colonizing the gastrointestinal tract of humans and numerous hosts across the animal kingdom. Enterococci are also a leading cause of multidrug-resistant hospital-acquired infections. In each of these settings, enterococci must contend with changing biophysical landscapes and innate immune responses in order to successfully colonize and transit between hosts. Therefore, it appears that the intrinsic durability that evolved to make enterococci optimally competitive in the host gastrointestinal tract also ideally positioned them to persist in hospitals, despite disinfection protocols, and acquire new antibiotic resistances from other microbes. Here, we discuss the molecular mechanisms and regulation employed by enterococci to tolerate diverse stressors and highlight the role of stress tolerance in the biology of this medically relevant genus.
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Nóbrega CS, Pauleta SR. Reduction of hydrogen peroxide in gram-negative bacteria - bacterial peroxidases. Adv Microb Physiol 2019; 74:415-464. [PMID: 31126534 DOI: 10.1016/bs.ampbs.2019.02.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Bacteria display an array of enzymes to detoxify reactive oxygen species that cause damage to DNA and to other biomolecules leading to cell death. Hydrogen peroxide is one of these species, with endogenous and exogenous sources, such as lactic acid bacteria, oxidative burst of the immune system or chemical reactions at oxic-anoxic interfaces. The enzymes that detoxify hydrogen peroxide will be the focus of this review, with special emphasis on bacterial peroxidases that reduce hydrogen peroxide to water. Bacterial peroxidases are periplasmic cytochromes with either two or three c-type haems, which have been classified as classical and non-classical bacterial peroxidases, respectively. Most of the studies have been focus on the classical bacterial peroxidases, showing the presence of a reductive activation in the presence of calcium ions. Mutagenesis studies have clarified the catalytic mechanism of this enzyme and were used to propose an intramolecular electron transfer pathway, with far less being known about the intermolecular electron transfer that occurs between reduced electron donors and the enzyme. The physiological function of these enzymes was not very clear until it was shown, for the non-classical bacterial peroxidase, that this enzyme is required for the bacteria to use hydrogen peroxide as terminal electron acceptor under anoxic conditions. These non-classical bacterial peroxidases are quinol peroxidases that do not require reductive activation but need calcium ions to attain maximum activity and share similar catalytic intermediates with the classical bacterial peroxidases.
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Affiliation(s)
- Cláudia S Nóbrega
- Microbial Stress Lab, UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Sofia R Pauleta
- Microbial Stress Lab, UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
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Nasser A, Moradi M, Jazireian P, Safari H, Alizadeh-Sani M, Pourmand MR, Azimi T. Staphylococcus aureus versus neutrophil: Scrutiny of ancient combat. Microb Pathog 2019; 131:259-269. [PMID: 31002964 DOI: 10.1016/j.micpath.2019.04.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/12/2019] [Accepted: 04/15/2019] [Indexed: 12/11/2022]
Abstract
Staphylococcus aureus (S.aureus) is a Gram-positive bacterium that causes many infections and diseases. This pathogen can cause many types of infections such as impetigo, toxic shock syndrome toxin (TSST1), pneumonia, endocarditis, and autoimmune diseases like lupus erythematosus and can infect other healthy individuals. In the pathogenic process, colonization is a main risk factor for invasive diseases. Various factors including the cell wall-associated factors and receptors of the epithelial cells facilitate adhesion and colonization of this pathogen. S. aureus has many enzymes, toxins, and strategies to evade from the immune system either by an enzyme that lyses cellular component or by hiding from the immune system via surface antigens like protein A and second immunoglobulin-binding protein (Sbi). The strategies of this bacterium can be divided into five groups: A: Inhibit neutrophil recruitment B: Inhibit phagocytosis C: Inhibit killing by ROS, D: Neutrophil killing, and E: Resistance to antimicrobial peptide. On the other hand, innate immune system via neutrophils, the most important polymorphonuclear leukocytes, fights against bacterial cells by neutrophil extracellular trap (NET). In this review, we try to explain the role of each factor in immune evasion.
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Affiliation(s)
- Ahmad Nasser
- Microbiology Research center, Ilam University of Medical Sciences, Ilam, Iran; Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Melika Moradi
- Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Parham Jazireian
- Department of Biology, University Campus 2,University of Guilan, Rasht, Iran
| | - Hossein Safari
- Health Promotion Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mahmood Alizadeh-Sani
- Food Safety and Hygiene Division, Environmental Health Department, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; Students Research Committee, Department of Food Sciences and Technology, Faculty of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Reza Pourmand
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Taher Azimi
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
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Bjørklund G, Aaseth J, Dadar M, Chirumbolo S. Molecular Targets in Alzheimer’s Disease. Mol Neurobiol 2019; 56:7032-7044. [DOI: 10.1007/s12035-019-1563-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 03/13/2019] [Indexed: 12/27/2022]
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Role of peroxiredoxin of the AhpC/TSA family in antioxidant defense mechanisms of Francisella tularensis. PLoS One 2019; 14:e0213699. [PMID: 30870480 PMCID: PMC6417708 DOI: 10.1371/journal.pone.0213699] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 02/23/2019] [Indexed: 12/16/2022] Open
Abstract
Francisella tularensis is a Gram-negative, facultative intracellular pathogen and the causative agent of a lethal human disease known as tularemia. Due to its extremely high virulence and potential to be used as a bioterror agent, F. tularensis is classified by the CDC as a Category A Select Agent. As an intracellular pathogen, F. tularensis during its intracellular residence encounters a number of oxidative and nitrosative stresses. The roles of the primary antioxidant enzymes SodB, SodC and KatG in oxidative stress resistance and virulence of F. tularensis live vaccine strain (LVS) have been characterized in previous studies. However, very fragmentary information is available regarding the role of peroxiredoxin of the AhpC/TSA family (annotated as AhpC) of F. tularensis SchuS4; whereas the role of AhpC of F. tularensis LVS in tularemia pathogenesis is not known. This study was undertaken to exhaustively investigate the role of AhpC in oxidative stress resistance of F. tularensis LVS and SchuS4. We report that AhpC of F. tularensis LVS confers resistance against a wide range of reactive oxygen and nitrogen species, and serves as a virulence factor. In highly virulent F. tularensis SchuS4 strain, AhpC serves as a key antioxidant enzyme and contributes to its robust oxidative and nitrosative stress resistance, and intramacrophage survival. We also demonstrate that there is functional redundancy among primary antioxidant enzymes AhpC, SodC, and KatG of F. tularensis SchuS4. Collectively, this study highlights the differences in antioxidant defense mechanisms of F. tularensis LVS and SchuS4.
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Korir ML, Flaherty RA, Rogers LM, Gaddy JA, Aronoff DM, Manning SD. Investigation of the Role That NADH Peroxidase Plays in Oxidative Stress Survival in Group B Streptococcus. Front Microbiol 2018; 9:2786. [PMID: 30515142 PMCID: PMC6255910 DOI: 10.3389/fmicb.2018.02786] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 10/30/2018] [Indexed: 02/02/2023] Open
Abstract
Macrophages play an important role in defending the host against infections by engulfing pathogens and containing them inside the phagosome, which consists of a harsh microbicidal environment. However, many pathogens have developed mechanisms to survive inside macrophages despite this challenge. Group B Streptococcus (GBS), a leading cause of sepsis and meningitis in neonates, is one such pathogen that survives inside macrophages by withstanding phagosomal stress. Although a few key intracellular survival factors have been identified, the mechanisms by which GBS detoxifies the phagosome are poorly defined. Transcriptional analysis during survival inside macrophages revealed strong upregulation of a putative NADH peroxidase (npx) at 1 and 24 h post-infection. A deletion mutant of npx (Δnpx) was more susceptible to killing by a complex in vitro model of multiple phagosomal biochemical/oxidant stressors or by hydrogen peroxide alone. Moreover, compared to an isogenic wild type GBS strain, the Δnpx strain demonstrated impaired survival inside human macrophages and a reduced capacity to blunt macrophage reactive oxygen species (ROS) production. It is therefore likely that Npx plays a role in survival against ROS production in the macrophage. A more thorough understanding of how GBS evades the immune system through survival inside macrophages will aid in development of new therapeutic measures.
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Affiliation(s)
- Michelle L Korir
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
| | - Rebecca A Flaherty
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
| | - Lisa M Rogers
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Jennifer A Gaddy
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States.,Tennessee Valley Healthcare Systems, Department of Veterans Affairs, Nashville, TN, United States.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - David M Aronoff
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States.,Department of Obstetrics and Gynecology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Shannon D Manning
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
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Catalase Expression in Azospirillum brasilense Sp7 Is Regulated by a Network Consisting of OxyR and Two RpoH Paralogs and Including an RpoE1→RpoH5 Regulatory Cascade. Appl Environ Microbiol 2018; 84:AEM.01787-18. [PMID: 30217849 DOI: 10.1128/aem.01787-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 09/01/2018] [Indexed: 12/19/2022] Open
Abstract
The genome of Azospirillum brasilense encodes five RpoH sigma factors: two OxyR transcription regulators and three catalases. The aim of this study was to understand the role they play during oxidative stress and their regulatory interconnection. Out of the 5 paralogs of RpoH present in A. brasilense, inactivation of only rpoH1 renders A. brasilense heat sensitive. While transcript levels of rpoH1 were elevated by heat stress, those of rpoH3 and rpoH5 were upregulated by H2O2 Catalase activity was upregulated in A. brasilense and its rpoH::km mutants in response to H2O2 except in the case of the rpoH5::km mutant, suggesting a role for RpoH5 in regulating inducible catalase. Transcriptional analysis of the katN, katAI, and katAII genes revealed that the expression of katN and katAII was severely compromised in the rpoH3::km and rpoH5::km mutants, respectively. Regulation of katN and katAII by RpoH3 and RpoH5, respectively, was further confirmed in an Escherichia coli two-plasmid system. Regulation of katAII by OxyR2 was evident by a drastic reduction in growth, KatAII activity, and katAII::lacZ expression in an oxyR2::km mutant. This study reports the involvement of RpoH3 and RpoH5 sigma factors in regulating oxidative stress response in alphaproteobacteria. We also report the regulation of an inducible catalase by a cascade of alternative sigma factors and an OxyR. Out of the three catalases in A. brasilense, those corresponding to katN and katAII are regulated by RpoH3 and RpoH5, respectively. The expression of katAII is regulated by a cascade of RpoE1→RpoH5 and OxyR2.IMPORTANCE In silico analysis of the A. brasilense genome showed the presence of multiple paralogs of genes involved in oxidative stress response, which included 2 OxyR transcription regulators and 3 catalases. So far, Deinococcus radiodurans and Vibrio cholerae are known to harbor two paralogs of OxyR, and Sinorhizobium meliloti harbors three catalases. We do not yet know how the expression of multiple catalases is regulated in any bacterium. Here we show the role of multiple RpoH sigma factors and OxyR in regulating the expression of multiple catalases in A. brasilense Sp7. Our work gives a glimpse of systems biology of A. brasilense used for responding to oxidative stress.
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Medina M, Rizo A, Dinh D, Chau B, Omidvar M, Juarez A, Ngo J, Johnson HA. MopA, the Mn Oxidizing Protein From Erythrobacter sp. SD-21, Requires Heme and NAD + for Mn(II) Oxidation. Front Microbiol 2018; 9:2671. [PMID: 30487779 PMCID: PMC6247904 DOI: 10.3389/fmicb.2018.02671] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 10/19/2018] [Indexed: 11/15/2022] Open
Abstract
Bacterial manganese (Mn) oxidation is catalyzed by a diverse group of microbes and can affect the fate of other elements in the environment. Yet, we understand little about the enzymes that catalyze this reaction. The Mn oxidizing protein MopA, from Erythrobacter sp. strain SD-21, is a heme peroxidase capable of Mn(II) oxidation. Unlike Mn oxidizing multicopper oxidase enzymes, an understanding of MopA is very limited. Sequence analysis indicates that MopA contains an N-terminal heme peroxidase domain and a C-terminal calcium binding domain. Heterologous expression and nickel affinity chromatography purification of the N-terminal peroxidase domain (MopA-hp) from Erythrobacter sp. strain SD-21 led to partial purification. MopA-hp is a heme binding protein that requires heme, NAD+, and calcium (Ca2+) for activity. Mn oxidation is also stimulated by the presence of pyrroloquinoline quinone. MopA-hp has a KM for Mn(II) of 154 ± 46 μM and kcat = 1.6 min−1. Although oxygen requiring MopA-hp is homologous to peroxidases based on sequence, addition of hydrogen peroxide and hydrogen peroxide scavengers had little effect on Mn oxidation, suggesting this is not the oxidizing agent. These studies provide insight into the mechanism by which MopA oxidizes Mn.
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Affiliation(s)
- Michael Medina
- Department of Biological Science, Center for Applied Biotechnology Studies, California State University Fullerton, Fullerton, CA, United States
| | - Antonia Rizo
- Department of Biological Science, Center for Applied Biotechnology Studies, California State University Fullerton, Fullerton, CA, United States
| | - David Dinh
- Department of Biological Science, Center for Applied Biotechnology Studies, California State University Fullerton, Fullerton, CA, United States
| | - Briana Chau
- Department of Biological Science, Center for Applied Biotechnology Studies, California State University Fullerton, Fullerton, CA, United States
| | - Moussa Omidvar
- Department of Biological Science, Center for Applied Biotechnology Studies, California State University Fullerton, Fullerton, CA, United States
| | - Andrew Juarez
- Department of Biological Science, Center for Applied Biotechnology Studies, California State University Fullerton, Fullerton, CA, United States
| | - Julia Ngo
- Department of Biological Science, Center for Applied Biotechnology Studies, California State University Fullerton, Fullerton, CA, United States
| | - Hope A Johnson
- Department of Biological Science, Center for Applied Biotechnology Studies, California State University Fullerton, Fullerton, CA, United States
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Gene Regulation by Redox-Sensitive Burkholderia thailandensis OhrR and Its Role in Bacterial Killing of Caenorhabditis elegans. Infect Immun 2018; 86:IAI.00322-18. [PMID: 29967095 DOI: 10.1128/iai.00322-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 06/26/2018] [Indexed: 12/16/2022] Open
Abstract
Fatty acid hydroperoxides are involved in host-pathogen interactions. In both plants and mammals, polyunsaturated fatty acids are liberated during infection and enzymatically oxidized to the corresponding toxic hydroperoxides during the defensive oxidative burst that is designed to thwart the infection. The bacterial transcription factor OhrR (organic hydroperoxide reductase regulator) is oxidized by organic hydroperoxides, as a result of which the ohr gene encoding organic hydroperoxide reductase is induced. This enzyme converts the hydroperoxides to less toxic alcohols. We show here that OhrR from Burkholderia thailandensis represses expression of ohr Gene expression is induced by cumene hydroperoxide and to a lesser extent by inorganic oxidants; however, Ohr contributes to degradation only of the organic hydroperoxide. B. thailandensis OhrR, which binds specific sites in both ohr and ohrR promoters, as evidenced by DNase I footprinting, belongs to the 2-Cys subfamily of OhrR proteins, and its oxidation leads to reversible disulfide bond formation between conserved N- and C-terminal cysteines in separate monomers. Oxidation of the N-terminal Cys is sufficient for attenuation of DNA binding in vitro, with complete restoration of DNA binding occurring on addition of a reducing agent. Surprisingly, both overexpression of ohr and deletion of ohr results in enhanced survival on exposure to organic hydroperoxide in vitro While Δohr cells are more virulent in a Caenorhabditis elegans model of infection, ΔohrR cells are less so. Taken together, our data suggest that B. thailandensis OhrR has several unconventional features and that both OhrR and organic hydroperoxides may contribute to virulence.
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Ontañon OM, Landi C, Carleo A, Gagliardi A, Bianchi L, González PS, Agostini E, Bini L. What makes A. guillouiae SFC 500-1A able to co-metabolize phenol and Cr(VI)? A proteomic approach. JOURNAL OF HAZARDOUS MATERIALS 2018; 354:215-224. [PMID: 29753190 DOI: 10.1016/j.jhazmat.2018.04.068] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 06/08/2023]
Abstract
Acinetobacter guillouiae SFC 500-1A is an environmental bacterium able to efficiently co-remediate phenol and Cr(VI). To further understand the molecular mechanisms triggered in this strain during the bioremediation process, variations in the proteomic profile after treatment with phenol and phenol plus Cr(VI) were evaluated. The proteomic analysis revealed the induction of the β-ketoadipate pathway for phenol oxidation and the assimilation of degradation products through TCA cycle and glyoxylate shunt. Phenol exposure increased the abundance of proteins associated to energetic processes and ATP synthesis, but it also triggered cellular stress. The lipid bilayer was suggested as a target of phenol toxicity, and changing fatty acids composition seemed to be the bacterial response to protect the membrane integrity. The involvement of two flavoproteins in Cr(VI) reduction to Cr(III) was also proposed. The results suggested the important role of chaperones, antioxidant response and SOS-induced proteins in the ability of the strain to mitigate the damage generated by phenol and Cr(VI). This research contributes to elucidate the mechanisms involved in A. guillouiae SFC 500-1A tolerance and co-remediation of phenol and Cr(VI). Such information may result useful not only to improve its bioremediation efficiency but also to identify putative markers of resistance in environmental bacteria.
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Affiliation(s)
- Ornella Mailén Ontañon
- Department of Molecular Biology, National University of Rio Cuarto, Córdoba, Argentina; National Council for Scientific and Technological Research (CONICET), Argentina.
| | - Claudia Landi
- Laboratory of Functional Proteomics, Department of Life Sciences, University of Siena, Siena, Italy
| | - Alfonso Carleo
- Laboratory of Functional Proteomics, Department of Life Sciences, University of Siena, Siena, Italy; Current address: Department of Pulmonology, Hannover Medical School, Hannover, Germany
| | - Assunta Gagliardi
- Laboratory of Functional Proteomics, Department of Life Sciences, University of Siena, Siena, Italy; Current address: Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Laura Bianchi
- Laboratory of Functional Proteomics, Department of Life Sciences, University of Siena, Siena, Italy
| | - Paola Solange González
- Department of Molecular Biology, National University of Rio Cuarto, Córdoba, Argentina; National Council for Scientific and Technological Research (CONICET), Argentina
| | - Elizabeth Agostini
- Department of Molecular Biology, National University of Rio Cuarto, Córdoba, Argentina; National Council for Scientific and Technological Research (CONICET), Argentina
| | - Luca Bini
- Laboratory of Functional Proteomics, Department of Life Sciences, University of Siena, Siena, Italy
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Lou H, Wang X, Chen J, Wang B, Wang W. Transcriptomic response of Ralstonia solanacearum to antimicrobial Pseudomonas fluorescens SN15-2 metabolites. Can J Microbiol 2018; 64:816-825. [PMID: 29852076 DOI: 10.1139/cjm-2018-0094] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
To develop efficient biocontrol agents, it is essential to investigate the response of soil-borne plant pathogens to such agents. For example, the response of Ralstonia solanacearum, the tomato wilt pathogen, to antimicrobial metabolites of Pseudomonas fluorescens is unknown. Thus, we assessed the effects of P. fluorescens SN15-2 fermentation broth on R. solanacearum by transmission electron microscopy and transcriptome technology. RNA sequencing identified 109 and 155 genes that are significantly upregulated and downregulated, respectively, in response to P. fluorescens metabolites, many of which are associated with the cell membrane and cell wall, and with nucleotide acid metabolism, iron absorption, and response to oxidative stress. This study highlights the effectiveness of P. fluorescens metabolites against the tomato wilt pathogen and helps clarify the underlying molecular mechanisms.
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Affiliation(s)
- Haibo Lou
- a State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xiaobing Wang
- a State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Jun Chen
- a State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Bozhi Wang
- b School of Information Science and Technology, Fudan University, Shanghai, 200433, China
| | - Wei Wang
- a State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
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A novel soxO gene, encoding a glutathione disulfide reductase, is essential for tetrathionate oxidation in Advenella kashmirensis. Microbiol Res 2017; 205:1-7. [DOI: 10.1016/j.micres.2017.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/19/2017] [Accepted: 08/05/2017] [Indexed: 11/30/2022]
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Goh HMS, Yong MHA, Chong KKL, Kline KA. Model systems for the study of Enterococcal colonization and infection. Virulence 2017; 8:1525-1562. [PMID: 28102784 PMCID: PMC5810481 DOI: 10.1080/21505594.2017.1279766] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 12/30/2016] [Accepted: 01/04/2017] [Indexed: 02/07/2023] Open
Abstract
Enterococcus faecalis and Enterococcus faecium are common inhabitants of the human gastrointestinal tract, as well as frequent opportunistic pathogens. Enterococci cause a range of infections including, most frequently, infections of the urinary tract, catheterized urinary tract, bloodstream, wounds and surgical sites, and heart valves in endocarditis. Enterococcal infections are often biofilm-associated, polymicrobial in nature, and resistant to antibiotics of last resort. Understanding Enterococcal mechanisms of colonization and pathogenesis are important for identifying new ways to manage and intervene with these infections. We review vertebrate and invertebrate model systems applied to study the most common E. faecalis and E. faecium infections, with emphasis on recent findings examining Enterococcal-host interactions using these models. We discuss strengths and shortcomings of each model, propose future animal models not yet applied to study mono- and polymicrobial infections involving E. faecalis and E. faecium, and comment on the significance of anti-virulence strategies derived from a fundamental understanding of host-pathogen interactions in model systems.
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Affiliation(s)
- H. M. Sharon Goh
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - M. H. Adeline Yong
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Kelvin Kian Long Chong
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate School, Nanyang Technological University, Singapore
| | - Kimberly A. Kline
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
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35
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Sobrado P, Gadda G. Introduction to flavoproteins: Beyond the classical paradigms. Arch Biochem Biophys 2017; 632:1-3. [DOI: 10.1016/j.abb.2017.08.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2017] [Indexed: 02/08/2023]
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36
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Borotto NB, McClory PJ, Martin BR, Håkansson K. Targeted Annotation of S-Sulfonylated Peptides by Selective Infrared Multiphoton Dissociation Mass Spectrometry. Anal Chem 2017; 89:8304-8310. [PMID: 28708386 DOI: 10.1021/acs.analchem.7b01461] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Protein S-sulfinylation (R-SO2-) and S-sulfonylation (R-SO3-) are irreversible oxidative post-translational modifications of cysteine residues. Greater than 5% of cysteines are reported to occupy these higher oxidation states, which effectively inactivate the corresponding thiols and alter the electronic and physical properties of modified proteins. Such higher oxidation states are reached after excessive exposure to cellular oxidants, and accumulate across different disease states. Despite widespread and functionally relevant cysteine oxidation across the proteome, there are currently no robust methods to profile higher order cysteine oxidation. Traditional data-dependent liquid chromatography/tandem mass spectrometry (LC/MS/MS) methods generally miss low-occupancy modifications in complex analyses. Here, we present a data-independent acquisition (DIA) LC/MS-based approach, leveraging the high IR absorbance of sulfoxides at 10.6 μm, for selective dissociation and discovery of S-sulfonated peptides. Across peptide standards and protein digests, we demonstrate selective infrared multiphoton dissociation (IRMPD) of S-sulfonated peptides in the background of unmodified peptides. This selective DIA IRMPD LC/MS-based approach allows identification and annotation of S-sulfonated peptides across complex mixtures while providing sufficient sequence information to localize the modification site.
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Affiliation(s)
- Nicholas B Borotto
- Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Phillip J McClory
- Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Brent R Martin
- Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Kristina Håkansson
- Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
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Wang X, Hu B, Wen C, Zhang M, Jian S, Yang G. Molecular cloning, expression and antioxidative activity of 2-cys-peroxiredoxin from freshwater mussel Cristaria plicata. FISH & SHELLFISH IMMUNOLOGY 2017; 66:254-263. [PMID: 28499967 DOI: 10.1016/j.fsi.2017.05.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/25/2017] [Accepted: 05/08/2017] [Indexed: 06/07/2023]
Abstract
Peroxiredoxins (Prxs) play an important role against various oxidative stresses by catalyzing the reduction of hydrogen peroxide (H2O2) and organic hydroperoxides to less harmful form. A 2-cys peroxiredoxin, designated as CpPrx, was cloned from hemocytes of freshwater mussel Cristaria plicata. The full length cDNA of CpPrx is 1247 bp, which includes an open reading frame (ORF) of 591bp, encoding 196 amino acids. CpPrx possesses two conserved cysteine residues (Cys49, Cys170). The deduced amino acid sequence of CpPrx showed a high level (67-74%) of sequence similarity to 2-Cys Prxs from other species. The results of real-time quantitative PCR revealed that CpPrx mRNA was constitutively expressed in tissues, and the highest expression levels were in hepatopancreas and gills. After peptidoglycan (PGN) and Aeromonas hydrophila challenge, the expression levels of CpPrx mRNA were up-regulated in hemocytes and hepatopancreas. The cDNA of CpPrx was cloned into the plasmid pET-32, and the recombinant protein was expressed in Escherichia coli BL21(DE3). Comparison with DE3-pET-32 and DE3 strain, the cells of DE3-pET-32-CpPrx exhibited resistance to the concentration of 0.4, 0.8 and 1.2 mmoL/L H2O2 in vivo.
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Affiliation(s)
- Xiaobo Wang
- School of Life Sciences, Nanchang University, Nanchang 330031, China
| | - Baoqing Hu
- School of Life Sciences, Nanchang University, Nanchang 330031, China
| | - Chungen Wen
- School of Life Sciences, Nanchang University, Nanchang 330031, China.
| | - Ming Zhang
- College of Jiangxi Biotech Vocational, Nanchang 330200, China.
| | - Shaoqing Jian
- School of Life Sciences, Nanchang University, Nanchang 330031, China
| | - Gang Yang
- School of Life Sciences, Nanchang University, Nanchang 330031, China
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Mechanism of antagonistic effects of Andrographis paniculata methanolic extract against Staphylococcus aureus. ASIAN PAC J TROP MED 2017; 10:685-695. [DOI: 10.1016/j.apjtm.2017.07.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 05/17/2017] [Accepted: 06/23/2017] [Indexed: 11/19/2022] Open
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39
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Núñez-Díaz JA, Fumanal M, Viguera E, Moriñigo MA, Balebona MC. Use of in vivo induced technology to identify antigens expressed by Photobacterium damselae subsp. piscicida during infection of Senegalese sole (Solea senegalensis). FISH & SHELLFISH IMMUNOLOGY 2017; 64:446-456. [PMID: 28359946 DOI: 10.1016/j.fsi.2017.03.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 03/22/2017] [Accepted: 03/26/2017] [Indexed: 06/07/2023]
Abstract
Photobacterium damselae subsp. piscicida (Phdp), the causative agent of photobacteriosis, is an important pathogen in marine aquaculture that affects many different fish species worldwide, including Solea senegalensis, an important fish species for aquaculture in the south of Europe. Bacteria express different repertoires of proteins in response to environmental conditions and when invading a host, sense in vivo environment and adapt by changing the expression of specific proteins. In the case of pathogens, identification of genes with up-regulated expression in vivo compared to in vitro conditions might give an insight into the genes relevant to the bacterial virulence. In the present work, in vivo induced antigen technology (IVIAT) has been used to search for Phdp genes only expressed or up-regulated in infected S. senegalensis. An expression library from Phdp was assayed against pooled sera from convalescent S. senegalensis specimens and 18 clones were positive, indicating that proteins encoded are expressed by Phdp during S. senegalensis infection and are immunogenic for this fish species. In addition, five proteins were reactive against adsorbed sera, indicating their in vivo induced character. Inosine-5'-monophosphate dehydrogenase, serine hydroxy methyltransferase and alanyl-tRNA synthethase, involved in aminoacid and nucleotide metabolism, the protein with antioxidant activity alkyl hydroperoxide reductase and a non-ribosomal peptide synthetase responsible for the synthesis of the siderophore piscibactin have been identified as antigens induced in Phdp during S. senegalensis infection. Proteins induced during in vivo growth of Phdp represent promising targets for the development of novel antimicrobial or prophylactic agents in the treatment and prevention of photobacteriosis.
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Affiliation(s)
- J A Núñez-Díaz
- Universidad de Málaga, Departamento de Microbiología, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - M Fumanal
- Universidad de Málaga, Departamento de Microbiología, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - E Viguera
- Universidad de Málaga, Área de Genética, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - M A Moriñigo
- Universidad de Málaga, Departamento de Microbiología, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - M C Balebona
- Universidad de Málaga, Departamento de Microbiología, Campus de Teatinos s/n, 29071 Málaga, Spain.
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Vimal A, Kumar A. The morpheein model of allosterism: a remedial step for targeting virulent l -asparaginase. Drug Discov Today 2017; 22:814-822. [DOI: 10.1016/j.drudis.2016.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 09/02/2016] [Accepted: 10/03/2016] [Indexed: 11/15/2022]
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41
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The structure of Lactococcus lactis thioredoxin reductase reveals molecular features of photo-oxidative damage. Sci Rep 2017; 7:46282. [PMID: 28397795 PMCID: PMC5387739 DOI: 10.1038/srep46282] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/13/2017] [Indexed: 11/08/2022] Open
Abstract
The NADPH-dependent homodimeric flavoenzyme thioredoxin reductase (TrxR) provides reducing equivalents to thioredoxin, a key regulator of various cellular redox processes. Crystal structures of photo-inactivated thioredoxin reductase (TrxR) from the Gram-positive bacterium Lactococcus lactis have been determined. These structures reveal novel molecular features that provide further insight into the mechanisms behind the sensitivity of this enzyme toward visible light. We propose that a pocket on the si-face of the isoalloxazine ring accommodates oxygen that reacts with photo-excited FAD generating superoxide and a flavin radical that oxidize the isoalloxazine ring C7α methyl group and a nearby tyrosine residue. This tyrosine and key residues surrounding the oxygen pocket are conserved in enzymes from related bacteria, including pathogens such as Staphylococcus aureus. Photo-sensitivity may thus be a widespread feature among bacterial TrxR with the described characteristics, which affords applications in clinical photo-therapy of drug-resistant bacteria.
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Type VI secretion system contributes to Enterohemorrhagic Escherichia coli virulence by secreting catalase against host reactive oxygen species (ROS). PLoS Pathog 2017; 13:e1006246. [PMID: 28288207 PMCID: PMC5363993 DOI: 10.1371/journal.ppat.1006246] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 03/23/2017] [Accepted: 02/16/2017] [Indexed: 01/19/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) is one major type of contagious and foodborne pathogens. The type VI secretion system (T6SS) has been shown to be involved in the bacterial pathogenicity and bacteria-bacteria competition. Here, we show that EHEC could secrete a novel effector KatN, a Mn-containing catalase, in a T6SS-dependent manner. Expression of katN is promoted by RpoS and OxyR and repressed by H-NS, and katN contributes to bacterial growth under oxidative stress in vitro. KatN could be secreted into host cell cytosol after EHEC is phagocytized by macrophage, which leads to decreased level of intracellular reactive oxygen species (ROS) and facilitates the intramacrophage survival of EHEC. Finally, animal model results show that the deletion mutant of T6SS was attenuated in virulence compared with the wild type strain, while the deletion mutant of katN had comparable virulence to the wild type strain. Taken together, our findings suggest that EHEC could sense oxidative stress in phagosome and decrease the host cell ROS by secreting catalase KatN to facilitate its survival in the host cells.
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Kamariah N, Eisenhaber B, Eisenhaber F, Grüber G. Essential role of the flexible linker on the conformational equilibrium of bacterial peroxiredoxin reductase for effective regeneration of peroxiredoxin. J Biol Chem 2017; 292:6667-6679. [PMID: 28270505 DOI: 10.1074/jbc.m117.775858] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 02/27/2017] [Indexed: 12/13/2022] Open
Abstract
Reactive oxygen species (ROS) can damage DNA, proteins, and lipids, so cells have antioxidant systems that regulate ROS. In many bacteria, a dedicated peroxiredoxin reductase, alkyl hydroperoxide reductase subunit F (AhpF), catalyzes the rapid reduction of the redox-active disulfide center of the antioxidant protein peroxiredoxin (AhpC) to detoxify ROS such as hydrogen peroxide, organic hydroperoxide, and peroxynitrite. AhpF is a flexible multidomain protein that enables a series of electron transfers among the redox centers by accepting reducing equivalents from NADH. A flexible linker connecting the N-terminal domain (NTD) and C-terminal domain (CTD) of AhpF suggests that the enzyme adopts a large-scale domain motion that alternates between the closed and open states to shuttle electrons from the CTD via the NTD to AhpC. Here, we conducted comprehensive mutational, biochemical, and biophysical analyses to gain insights into the role of the flexible linker and the residues critical for the domain motions of Escherichia coli AhpF (EcAhpF) during electron transfer. Small-angle X-ray scattering studies of linker mutants revealed that a group of charged residues, 200EKR202, is crucial for the swiveling motion of the NTD. Moreover, NADH binding significantly affected EcAhpF flexibility and the movement of the NTD relative to the CTD. The mutants also exhibited a decrease in H2O2 reduction by the AhpF-AhpC ensemble. We propose that a concerted movement involving the NTD, C-terminal NADH, and FAD domains, and the flexible linker between them is essential for optimal intra-domain cross-talk and for efficient electron transfer to the redox partner AhpC required for peroxidation.
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Affiliation(s)
- Neelagandan Kamariah
- From the Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore 138671
| | - Birgit Eisenhaber
- From the Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore 138671
| | - Frank Eisenhaber
- From the Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore 138671.,the School of Computer Engineering, Nanyang Technological University, Singapore 637553, Republic of Singapore
| | - Gerhard Grüber
- From the Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore 138671, .,the School of Biological Sciences, Nanyang Technological University, Singapore 637551, and
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44
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Genome and Proteome Analysis of Rhodococcus erythropolis MI2: Elucidation of the 4,4´-Dithiodibutyric Acid Catabolism. PLoS One 2016; 11:e0167539. [PMID: 27977722 PMCID: PMC5157978 DOI: 10.1371/journal.pone.0167539] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 11/15/2016] [Indexed: 01/02/2023] Open
Abstract
Rhodococcus erythropolis MI2 has the extraordinary ability to utilize the xenobiotic 4,4´-dithiodibutyric acid (DTDB). Cleavage of DTDB by the disulfide-reductase Nox, which is the only verified enzyme involved in DTDB-degradation, raised 4-mercaptobutyric acid (4MB). 4MB could act as building block of a novel polythioester with unknown properties. To completely unravel the catabolism of DTDB, the genome of R. erythropolis MI2 was sequenced, and subsequently the proteome was analyzed. The draft genome sequence consists of approximately 7.2 Mbp with an overall G+C content of 62.25% and 6,859 predicted protein-encoding genes. The genome of strain MI2 is composed of three replicons: one chromosome and two megaplasmids with sizes of 6.45, 0.4 and 0.35 Mbp, respectively. When cells of strain MI2 were cultivated with DTDB as sole carbon source and compared to cells grown with succinate, several interesting proteins with significantly higher expression levels were identified using 2D-PAGE and MALDI-TOF mass spectrometry. A putative luciferase-like monooxygenase-class F420-dependent oxidoreductase (RERY_05640), which is encoded by one of the 126 monooxygenase-encoding genes of the MI2-genome, showed a 3-fold increased expression level. This monooxygenase could oxidize the intermediate 4MB into 4-oxo-4-sulfanylbutyric acid. Next, a desulfurization step, which forms succinic acid and volatile hydrogen sulfide, is proposed. One gene coding for a putative desulfhydrase (RERY_06500) was identified in the genome of strain MI2. However, the gene product was not recognized in the proteome analyses. But, a significant expression level with a ratio of up to 7.3 was determined for a putative sulfide:quinone oxidoreductase (RERY_02710), which could also be involved in the abstraction of the sulfur group. As response to the toxicity of the intermediates, several stress response proteins were strongly expressed, including a superoxide dismutase (RERY_05600) and an osmotically induced protein (RERY_02670). Accordingly, novel insights in the catabolic pathway of DTDB were gained.
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45
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Maura D, Hazan R, Kitao T, Ballok AE, Rahme LG. Evidence for Direct Control of Virulence and Defense Gene Circuits by the Pseudomonas aeruginosa Quorum Sensing Regulator, MvfR. Sci Rep 2016; 6:34083. [PMID: 27678057 PMCID: PMC5039717 DOI: 10.1038/srep34083] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 09/01/2016] [Indexed: 12/21/2022] Open
Abstract
Pseudomonas aeruginosa defies eradication by antibiotics and is responsible for acute and chronic human infections due to a wide variety of virulence factors. Currently, it is believed that MvfR (PqsR) controls the expression of many of these factors indirectly via the pqs and phnAB operons. Here we provide strong evidence that MvfR may also bind and directly regulate the expression of additional 35 loci across the P. aeruginosa genome, including major regulators and virulence factors, such as the quorum sensing (QS) regulators lasR and rhlR, and genes involved in protein secretion, translation, and response to oxidative stress. We show that these anti-oxidant systems, AhpC-F, AhpB-TrxB2 and Dps, are critical for P. aeruginosa survival to reactive oxygen species and antibiotic tolerance. Considering that MvfR regulated compounds generate reactive oxygen species, this indicates a tightly regulated QS self-defense anti-poisoning system. These findings also challenge the current hierarchical regulation model of P. aeruginosa QS systems by revealing new interconnections between them that suggest a circular model. Moreover, they uncover a novel role for MvfR in self-defense that favors antibiotic tolerance and cell survival, further demonstrating MvfR as a highly desirable anti-virulence target.
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Affiliation(s)
- Damien Maura
- Department of Surgery, Massachusetts General Hospital, Boston MA 02114, USA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston MA 02115, USA.,Shriners Hospitals for Children Boston, Boston, 02114, Massachusetts, USA
| | - Ronen Hazan
- Department of Surgery, Massachusetts General Hospital, Boston MA 02114, USA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston MA 02115, USA.,Shriners Hospitals for Children Boston, Boston, 02114, Massachusetts, USA.,Institute of Dental Sciences and School of Dental Medicine, Hebrew University, Jerusalem P.O.B 12272, 91120, Israel
| | - Tomoe Kitao
- Department of Surgery, Massachusetts General Hospital, Boston MA 02114, USA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston MA 02115, USA.,Shriners Hospitals for Children Boston, Boston, 02114, Massachusetts, USA
| | - Alicia E Ballok
- Department of Surgery, Massachusetts General Hospital, Boston MA 02114, USA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston MA 02115, USA.,Shriners Hospitals for Children Boston, Boston, 02114, Massachusetts, USA
| | - Laurence G Rahme
- Department of Surgery, Massachusetts General Hospital, Boston MA 02114, USA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston MA 02115, USA.,Shriners Hospitals for Children Boston, Boston, 02114, Massachusetts, USA
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46
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Weber GJ, Pushpakumar S, Tyagi SC, Sen U. Homocysteine and hydrogen sulfide in epigenetic, metabolic and microbiota related renovascular hypertension. Pharmacol Res 2016; 113:300-312. [PMID: 27602985 DOI: 10.1016/j.phrs.2016.09.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 08/31/2016] [Accepted: 09/02/2016] [Indexed: 12/18/2022]
Abstract
Over the past several years, hydrogen sulfide (H2S) has been shown to be an important player in a variety of physiological functions, including neuromodulation, vasodilation, oxidant regulation, inflammation, and angiogenesis. H2S is synthesized primarily through metabolic processes from the amino acid cysteine and homocysteine in various organ systems including neuronal, cardiovascular, gastrointestinal, and kidney. Derangement of cysteine and homocysteine metabolism and clearance, particularly in the renal vasculature, leads to H2S biosynthesis deregulation causing or contributing to existing high blood pressure. While a variety of environmental influences, such as diet can have an effect on H2S regulation and function, genetic factors, and more recently epigenetics, also have a vital role in H2S regulation and function, and therefore disease initiation and progression. In addition, new research into the role of gut microbiota in the development of hypertension has highlighted the need to further explore these microorganisms and how they influence the levels of H2S throughout the body and possibly exploiting microbiota for use of hypertension treatment. In this review, we summarize recent advances in the field of hypertension research emphasizing renal contribution and how H2S physiology can be exploited as a possible therapeutic strategy to ameliorate kidney dysfunction as well as to control blood pressure.
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Affiliation(s)
- Gregory J Weber
- Department of Physiology, University of Louisville, School of Medicine, Louisville, KY 40202, United States
| | - Sathnur Pushpakumar
- Department of Physiology, University of Louisville, School of Medicine, Louisville, KY 40202, United States
| | - Suresh C Tyagi
- Department of Physiology, University of Louisville, School of Medicine, Louisville, KY 40202, United States
| | - Utpal Sen
- Department of Physiology, University of Louisville, School of Medicine, Louisville, KY 40202, United States.
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47
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Potentiation of hydrogen peroxide toxicity: From catalase inhibition to stable DNA-iron complexes. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2016; 773:274-281. [PMID: 28927535 DOI: 10.1016/j.mrrev.2016.08.006] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 08/29/2016] [Indexed: 12/15/2022]
Abstract
Hydrogen peroxide (H2O2) is unique among general toxins, because it is stable in abiotic environments at ambient temperature and neutral pH, yet rapidly kills any type of cells by producing highly-reactive hydroxyl radicals. This life-specific reactivity follows the distribution of soluble iron, Fe(II) (which combines with H2O2 to form the famous Fenton's reagent),Fe(II) is concentrated inside cells, but is virtually absent outside them. Because of the immediate danger of H2O2, all cells have powerful H2O2 scavengers, the equally famous catalases, which enable cells to survive thousand-fold higher concentrations of H2O2 and, in combination with adequate movement of H2O2 across membranes, make the killing H2O2 concentrations virtually impractical to generate in vivo. And yet, low concentrations of H2O2 are somehow used as an efficient biological weapon. Here we review several examples of how cells potentiate H2O2 toxicity with other chemicals. At first, these potentiators were thought to simply inhibit catalases, but recent findings with cyanide suggest that potentiators mostly promote the other side of Fenton's reaction, recruiting iron from cell depots into stable DNA-iron complexes that, in the presence of elevated H2O2, efficiently break duplex DNA, pulverizing the chromosome. This multifaceted potentiation of H2O2 toxicity results in robust and efficient killing.
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Yoshida K, Hashimoto M, Hori R, Adachi T, Okuyama H, Orikasa Y, Nagamine T, Shimizu S, Ueno A, Morita N. Bacterial Long-Chain Polyunsaturated Fatty Acids: Their Biosynthetic Genes, Functions, and Practical Use. Mar Drugs 2016; 14:E94. [PMID: 27187420 PMCID: PMC4882568 DOI: 10.3390/md14050094] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/23/2016] [Accepted: 04/29/2016] [Indexed: 02/06/2023] Open
Abstract
The nutritional and pharmaceutical values of long-chain polyunsaturated fatty acids (LC-PUFAs) such as arachidonic, eicosapentaenoic and docosahexaenoic acids have been well recognized. These LC-PUFAs are physiologically important compounds in bacteria and eukaryotes. Although little is known about the biosynthetic mechanisms and functions of LC-PUFAs in bacteria compared to those in higher organisms, a combination of genetic, bioinformatic, and molecular biological approaches to LC-PUFA-producing bacteria and some eukaryotes have revealed the notably diverse organization of the pfa genes encoding a polyunsaturated fatty acid synthase complex (PUFA synthase), the LC-PUFA biosynthetic processes, and tertiary structures of the domains of this enzyme. In bacteria, LC-PUFAs appear to take part in specific functions facilitating individual membrane proteins rather than in the adjustment of the physical fluidity of the whole cell membrane. Very long chain polyunsaturated hydrocarbons (LC-HCs) such as hentriacontanonaene are considered to be closely related to LC-PUFAs in their biosynthesis and function. The possible role of LC-HCs in strictly anaerobic bacteria under aerobic and anaerobic environments and the evolutionary relationships of anaerobic and aerobic bacteria carrying pfa-like genes are also discussed.
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Affiliation(s)
- Kiyohito Yoshida
- Laboratory of Ecological Genetics, Section of Environmental Biology, Faculty of Environmental Earth Science, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
| | - Mikako Hashimoto
- Course in Ecological Genetics, Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
| | - Ryuji Hori
- Technical Solution Center First Group, J-OIL MILLS, Inc., Chuo-ku, Tokyo 104-0044, Japan.
| | - Takumi Adachi
- Laboratory of Environmental Microbiology, Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
- Bioproduction Research Institute, Department of Life Science and Biotechnology, National Institute of Advanced Industrial Science and Technology (AIST), Toyohira-ku, Sapporo, Hokkaido 062-8517, Japan.
| | - Hidetoshi Okuyama
- Laboratory of Environmental Molecular Biology, Section of Environmental Biology, Faculty of Environmental Earth Science, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
| | - Yoshitake Orikasa
- Department Food Science, Obihiro University Agriculture Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
| | - Tadashi Nagamine
- ROM Co. Ltd., Togashi Bld., Chuo-ku, Sapporo, Hokkaido 060-0062, Japan.
| | - Satoru Shimizu
- Horonobe Research Institute for the Subsurface Environment, Northern Advancement Centre for Science and Technology, 5-3, Sakae-machi, Horonobe, Teshio-gun, Hokkaido 098-3221, Japan.
| | - Akio Ueno
- Horonobe Research Institute for the Subsurface Environment, Northern Advancement Centre for Science and Technology, 5-3, Sakae-machi, Horonobe, Teshio-gun, Hokkaido 098-3221, Japan.
| | - Naoki Morita
- Laboratory of Environmental Microbiology, Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
- Bioproduction Research Institute, Department of Life Science and Biotechnology, National Institute of Advanced Industrial Science and Technology (AIST), Toyohira-ku, Sapporo, Hokkaido 062-8517, Japan.
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49
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Abstract
SIGNIFICANCE Hydrogen peroxide (H2O2) is not only a key mediator of oxidative stress but also one of the most important cellular second messengers. This small short-lived molecule is involved in the regulation of a wide range of different biological processes, including regulation of cellular signaling pathways. Studying the role of H2O2 in living systems would be challenging without modern approaches. A genetically encoded fluorescent biosensor, HyPer, is one of the most effective tools for this purpose. RECENT ADVANCES HyPer has been used by many investigators of redox signaling in various models of different scales: from cytoplasmic subcompartments and single cells to tissues of whole organisms. In many studies, the results obtained using HyPer have enabled a better understanding of the roles of H2O2 in these biological processes. However, much remains to be learned. CRITICAL ISSUES In this review, we focus on the uses of HyPer. We provide a general description of HyPer and its improved versions. Separate chapters are devoted to the results obtained by various groups who have used this biosensor for their experiments in living cells and organisms. FUTURE DIRECTIONS HyPer is an effective tool for H2O2 imaging in living systems as indicated by the increasing numbers of publications each year since its development. However, this biosensor requires further improvements. In particular, much brighter and more pH-stable versions of HyPer are necessary for imaging in mammalian tissues. Antioxid. Redox Signal. 24, 731-751.
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Affiliation(s)
- Dmitry S Bilan
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Moscow, Russia
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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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