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Feng T, Wang J. Oxidative stress tolerance and antioxidant capacity of lactic acid bacteria as probiotic: a systematic review. Gut Microbes 2020; 12:1801944. [PMID: 32795116 PMCID: PMC7524341 DOI: 10.1080/19490976.2020.1801944] [Citation(s) in RCA: 191] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 07/15/2020] [Indexed: 02/03/2023] Open
Abstract
Lactic acid bacteria (LAB) are the most frequently used probiotics in fermented foods and beverages and as food supplements for humans or animals, owing to their multiple beneficial features, which appear to be partially associated with their antioxidant properties. LAB can help improve food quality and flavor and prevent numerous disorders caused by oxidation in the host. In this review, we discuss the oxidative stress tolerance, the antioxidant capacity related herewith, and the underlying mechanisms and signaling pathways in probiotic LAB. In addition, we discuss appropriate methods used to evaluate the antioxidant capacity of probiotic LAB. The aim of the present review is to provide an overview of the current state of the research associated with the oxidative stress tolerance and antioxidant capacity of LAB.
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Affiliation(s)
- Tao Feng
- Institute of Animal Husbandry and Veterinary Medicine (IAHVM), Beijing Academy of Agriculture and Forestry Sciences (BAAFS), Beijing, China
- Sino-US Joint Laboratory of Animal Science, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Jing Wang
- Institute of Animal Husbandry and Veterinary Medicine (IAHVM), Beijing Academy of Agriculture and Forestry Sciences (BAAFS), Beijing, China
- Sino-US Joint Laboratory of Animal Science, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
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Feng L, Peillex-Delphe C, Lü C, Wang D, Giannakis S, Pulgarin C. Employing bacterial mutations for the elucidation of photo-Fenton disinfection: Focus on the intracellular and extracellular inactivation mechanisms induced by UVA and H 2O 2. WATER RESEARCH 2020; 182:116049. [PMID: 32619683 DOI: 10.1016/j.watres.2020.116049] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 06/11/2023]
Abstract
The bacterial inactivation mechanisms by solar light and the photo-Fenton process is still a matter of debate. In this study, we bring evidence towards the elucidation of the mechanisms that govern photo-Fenton disinfection at near-neutral pH. With the use of porin-deficient and catalase over-producing E. coli strains, in conjunction with measurements of cell wall oxidation and permeability, we are able to i) highlight the role of the aforementioned components in bacterial inactivation and ii) localize the damages in the intracellular domain, despite the addition of the Fenton reagents in the bulk. We report that H2O2 oxidizes cell walls but under light the process is of low significance; UVA initiated an intracellular oxidation process based on excess accumulated H2O2, while the UVA+H2O2 and UVA+H2O2+Fe2+ processes have the same effect with light, albeit enhanced, as shown by malondialdehyde (MDA) production and ONPG hydrolysis rates. Finally, compared to the UVA-assisted photo-Fenton process, its solar counterpart is enhanced by the direct UVB effects on bacterial DNA. In conclusion, we have sufficient evidence to postulate that the photo-Fenton process is intracellular and propose the pathways that form the integrated bacterial inactivation mechanism by photo-Fenton.
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Affiliation(s)
- Ling Feng
- School of Ecology and Environment, Inner Mongolia University, University W. Road, 010021, Huhhot, Inner Mongolia, PR China
| | - Céline Peillex-Delphe
- School of Basic Sciences (SB), Institute of Chemical Science and Engineering (ISIC), Group of Advanced Oxidation Processes (GPAO), École Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015, Lausanne, Switzerland
| | - Changwei Lü
- School of Ecology and Environment, Inner Mongolia University, University W. Road, 010021, Huhhot, Inner Mongolia, PR China
| | - Da Wang
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, China
| | - Stefanos Giannakis
- Universidad Politécnica de Madrid (UPM), E.T.S. Ingenieros de Caminos, Canales y Puertos, Departamento de Ingeniería Civil: Hidráulica, Energía y Medio Ambiente, Unidad docente Ingeniería Sanitaria, c/ Profesor Aranguren, s/n, ES-28040, Madrid, Spain.
| | - Cesar Pulgarin
- School of Basic Sciences (SB), Institute of Chemical Science and Engineering (ISIC), Group of Advanced Oxidation Processes (GPAO), École Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015, Lausanne, Switzerland.
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Gingerich AD, Doja F, Thomason R, Tóth E, Bradshaw JL, Douglass MV, McDaniel LS, Rada B. Oxidative killing of encapsulated and nonencapsulated Streptococcus pneumoniae by lactoperoxidase-generated hypothiocyanite. PLoS One 2020; 15:e0236389. [PMID: 32730276 PMCID: PMC7392276 DOI: 10.1371/journal.pone.0236389] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 07/06/2020] [Indexed: 01/04/2023] Open
Abstract
Streptococcus pneumoniae (Pneumococcus) infections affect millions of people worldwide, cause serious mortality and represent a major economic burden. Despite recent successes due to pneumococcal vaccination and antibiotic use, Pneumococcus remains a significant medical problem. Airway epithelial cells, the primary responders to pneumococcal infection, orchestrate an extracellular antimicrobial system consisting of lactoperoxidase (LPO), thiocyanate anion and hydrogen peroxide (H2O2). LPO oxidizes thiocyanate using H2O2 into the final product hypothiocyanite that has antimicrobial effects against a wide range of microorganisms. However, hypothiocyanite’s effect on Pneumococcus has never been studied. Our aim was to determine whether hypothiocyanite can kill S. pneumoniae. Bactericidal activity was measured in a cell-free in vitro system by determining the number of surviving pneumococci via colony forming units on agar plates, while bacteriostatic activity was assessed by measuring optical density of bacteria in liquid cultures. Our results indicate that hypothiocyanite generated by LPO exerted robust killing of both encapsulated and nonencapsulated pneumococcal strains. Killing of S. pneumoniae by a commercially available hypothiocyanite-generating product was even more pronounced than that achieved with laboratory reagents. Catalase, an H2O2 scavenger, inhibited killing of pneumococcal by hypothiocyanite under all circumstances. Furthermore, the presence of the bacterial capsule or lytA-dependent autolysis had no effect on hypothiocyanite-mediated killing of pneumococci. On the contrary, a pneumococcal mutant deficient in pyruvate oxidase (main bacterial H2O2 source) had enhanced susceptibility to hypothiocyanite compared to its wild-type strain. Overall, results shown here indicate that numerous pneumococcal strains are susceptible to LPO-generated hypothiocyanite.
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Affiliation(s)
- Aaron D. Gingerich
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, United States of America
| | - Fayhaa Doja
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, United States of America
| | - Rachel Thomason
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, United States of America
| | - Eszter Tóth
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, United States of America
| | - Jessica L. Bradshaw
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Martin V. Douglass
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, United States of America
| | - Larry S. McDaniel
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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54
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Murgas CJ, Green SP, Forney AK, Korba RM, An SS, Kitten T, Lucas HR. Intracellular Metal Speciation in Streptococcus sanguinis Establishes SsaACB as Critical for Redox Maintenance. ACS Infect Dis 2020; 6:1906-1921. [PMID: 32329608 DOI: 10.1021/acsinfecdis.0c00132] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Streptococcus sanguinis is an oral commensal bacterium, but it can colonize pre-existing heart valve vegetations if introduced into the bloodstream, leading to infective endocarditis. Loss of Mn- or Fe-cofactored virulence determinants are thought to result in weakening of this bacterium. Indeed, intracellular Mn accumulation mediated by the lipoprotein SsaB, a component of the SsaACB transporter complex, has been shown to promote virulence for endocarditis and O2 tolerance. To delineate intracellular metal-ion abundance and redox speciation within S. sanguinis, we developed a protocol exploiting two spectroscopic techniques, Inductively coupled plasma-optical emission spectrometry (ICP-OES) and electron paramagnetic resonance (EPR) spectroscopy, to respectively quantify total intracellular metal concentrations and directly measure redox speciation of Fe and Mn within intact whole-cell samples. Addition of the cell-permeable siderophore deferoxamine shifts the oxidation states of accessible Fe and Mn from reduced-to-oxidized, as verified by magnetic moment calculations, aiding in the characterization of intracellular metal pools and metal sequestration levels for Mn2+ and Fe. We have applied this methodology to S. sanguinis and an SsaACB knockout strain (ΔssaACB), indicating that SsaACB mediates both Mn and Fe uptake, directly influencing the metal-ion pools available for biological inorganic pathways. Mn supplementation of ΔssaACB returns total intracellular Mn to wild-type levels, but it does not restore wild-type redox speciation or distribution of metal cofactor availability for either Mn or Fe. Our results highlight the biochemical basis for S. sanguinis oxidative resistance, revealing a dynamic role for SsaACB in controlling redox homeostasis by managing the intracellular Fe/Mn composition and distribution.
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Affiliation(s)
- Cody J. Murgas
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Shannon P. Green
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia 23298, United States
- Department of Microbiology & Immunology, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Ashley K. Forney
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Rachel M. Korba
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Seon-Sook An
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Todd Kitten
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia 23298, United States
- Department of Microbiology & Immunology, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Heather R. Lucas
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
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55
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Echlin H, Frank M, Rock C, Rosch JW. Role of the pyruvate metabolic network on carbohydrate metabolism and virulence in Streptococcus pneumoniae. Mol Microbiol 2020; 114:536-552. [PMID: 32495474 DOI: 10.1111/mmi.14557] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/27/2020] [Accepted: 05/22/2020] [Indexed: 11/30/2022]
Abstract
Streptococcus pneumoniae is a major human pathogen that must adapt to unique nutritional environments in several host niches. The pneumococcus can metabolize a range of carbohydrates that feed into glycolysis ending in pyruvate, which is catabolized by several enzymes. We investigated how the pneumococcus utilizes these enzymes to metabolize different carbohydrates and how this impacts survival in the host. Loss of ldh decreased bacterial burden in the nasopharynx and enhanced bacteremia in mice. Loss of spxB, pdhC or pfl2 decreased bacteremia and increased host survival. In glucose or galactose, loss of ldh increased capsule production, whereas loss of spxB and pdhC reduced capsule production. The pfl2 mutant exhibited reduced capsule production only in galactose. In glucose, pyruvate was metabolized primarily by LDH to generate lactate and NAD+ and by SpxB and PDHc to generate acetyl-CoA. In galactose, pyruvate metabolism was shunted toward acetyl-CoA production. The majority of acetyl-CoA generated by PFL was used to regenerate NAD+ with a subset used in capsule production, while the acetyl-CoA generated by SpxB and PDHc was utilized primarily for capsule biosynthesis. These data suggest that the pneumococcus can alter flux of pyruvate metabolism dependent on the carbohydrate present to succeed in distinct host niches.
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Affiliation(s)
- Haley Echlin
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Matthew Frank
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Charles Rock
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Jason W Rosch
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, USA
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56
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Knippel RJ, Wexler AG, Miller JM, Beavers WN, Weiss A, de Crécy-Lagard V, Edmonds KA, Giedroc DP, Skaar EP. Clostridioides difficile Senses and Hijacks Host Heme for Incorporation into an Oxidative Stress Defense System. Cell Host Microbe 2020; 28:411-421.e6. [PMID: 32526159 DOI: 10.1016/j.chom.2020.05.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 04/02/2020] [Accepted: 05/19/2020] [Indexed: 12/18/2022]
Abstract
Clostridioides difficile infection of the colon leads to severe inflammation and damage to the gastrointestinal epithelium due to the production of potent toxins. This inflammatory tissue damage causes the liberation of high concentrations of host heme at infection sites. Here, we identify the C. difficile heme-sensing membrane protein system (HsmRA) and show that this operon induces a protective response that repurposes heme to counteract antimicrobial oxidative stress responses. HsmR senses vertebrate heme, leading to increased expression of the hsmRA operon and subsequent deployment of HsmA to capture heme and reduce redox damage caused by inflammatory mediators of protection and antibiotic therapy. Strains with inactivated hsmR or hsmA have increased sensitivity to redox-active compounds and reduced colonization persistence in a murine model of relapse C. difficile infection. These results define a mechanism exploited by C. difficile to repurpose toxic heme within the inflamed gut as a shield against antimicrobial compounds.
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Affiliation(s)
- Reece J Knippel
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Aaron G Wexler
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jeanette M Miller
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
| | - William N Beavers
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Andy Weiss
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences and Genetics Institute, University of Florida, Gainesville, FL, USA
| | | | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA.
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57
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Gonzales-Siles L, Karlsson R, Schmidt P, Salvà-Serra F, Jaén-Luchoro D, Skovbjerg S, Moore ERB, Gomila M. A Pangenome Approach for Discerning Species-Unique Gene Markers for Identifications of Streptococcus pneumoniae and Streptococcus pseudopneumoniae. Front Cell Infect Microbiol 2020; 10:222. [PMID: 32509595 PMCID: PMC7248185 DOI: 10.3389/fcimb.2020.00222] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 04/22/2020] [Indexed: 01/28/2023] Open
Abstract
Correct identifications of isolates and strains of the Mitis-Group of the genus Streptococcus are particularly difficult, due to high genetic similarity, resulting from horizontal gene transfer and homologous recombination, and unreliable phenotypic and genotypic biomarkers for differentiating the species. Streptococcus pneumoniae and Streptococcus pseudopneumoniae are the most closely related species of the clade. In this study, publicly-available genome sequences for Streptococcus pneumoniae and S. pseudopneumoniae were analyzed, using a pangenomic approach, to find candidates for species-unique gene markers; ten species-unique genes for S. pneumoniae and nine for S. pseudopneumoniae were identified. These species-unique gene marker candidates were verified by PCR assays for identifying S. pneumoniae and S. pseudopneumoniae strains isolated from clinical samples. All determined species-level unique gene markers for S. pneumoniae were detected in all S. pneumoniae clinical isolates, whereas fewer of the unique S. pseudopneumoniae gene markers were present in more than 95% of the clinical isolates. In parallel, taxonomic identifications of the clinical isolates were confirmed, using conventional optochin sensitivity testing, targeted PCR-detection for the “Xisco” gene, as well as genomic ANIb similarity analyses for the genome sequences of selected strains. Using mass spectrometry-proteomics, species-specific peptide matches were observed for four of the S. pneumoniae gene markers and for three of the S. pseudopneumoniae gene markers. Application of multiple species-level unique biomarkers of S. pneumoniae and S. pseudopneumoniae, is proposed as a protocol for the routine clinical laboratory for improved, reliable differentiation, and identification of these pathogenic and commensal species.
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Affiliation(s)
- Lucia Gonzales-Siles
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Clinical Microbiology, Sahlgrenska University Hospital, Gothenburg, Sweden.,Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
| | - Roger Karlsson
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Clinical Microbiology, Sahlgrenska University Hospital, Gothenburg, Sweden.,Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
| | - Patrik Schmidt
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Francisco Salvà-Serra
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Clinical Microbiology, Sahlgrenska University Hospital, Gothenburg, Sweden.,Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden.,Culture Collection University of Gothenburg (CCUG), Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Biology-Microbiology, Universitat de les Illes Balears, Palma, Spain
| | - Daniel Jaén-Luchoro
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
| | - Susann Skovbjerg
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Clinical Microbiology, Sahlgrenska University Hospital, Gothenburg, Sweden.,Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
| | - Edward R B Moore
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Clinical Microbiology, Sahlgrenska University Hospital, Gothenburg, Sweden.,Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden.,Culture Collection University of Gothenburg (CCUG), Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Margarita Gomila
- Department of Biology-Microbiology, Universitat de les Illes Balears, Palma, Spain
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58
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Pyruvate secretion by oral streptococci modulates hydrogen peroxide dependent antagonism. THE ISME JOURNAL 2020; 14:1074-1088. [PMID: 31988475 PMCID: PMC7174352 DOI: 10.1038/s41396-020-0592-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 01/14/2020] [Accepted: 01/16/2020] [Indexed: 01/28/2023]
Abstract
Many commensal oral streptococci generate H2O2 via pyruvate oxidase (SpxB) to inhibit the growth of competing bacteria like Streptococcus mutans, a major cariogenic species. In Streptococcus sanguinis SK36 (SK36) and Streptococcus gordonii DL1 (DL1), spxB expression and H2O2 release are subject to carbon catabolite repression by the catabolite control protein A (CcpA). Surprisingly, ccpA deletion mutants of SK36 and DL1 fail to inhibit S. mutans despite their production of otherwise inhibitory levels of H2O2. Using H2O2-deficient spxB deletion mutants of SK36 and DL1, it was subsequently discovered that both strains confer protection in trans to other bacteria when H2O2 is added exogenously. This protective effect depends on the direct detoxification of H2O2 by the release of pyruvate. The pyruvate dependent protective effect is also present in other spxB-encoding streptococci, such as the pneumococcus, but is missing from spxB-negative species like S. mutans. Targeted and transposon-based mutagenesis revealed Nox (putative H2O-forming NADH dehydrogenase) as an essential component required for pyruvate release and oxidative protection, while other genes such as sodA and dps play minor roles. Furthermore, pyruvate secretion is only detectable in aerobic growth conditions at biofilm-like cell densities and is responsive to CcpA-dependent catabolite control. This ability of spxB-encoding streptococci reveals a new facet of the competitive interactions between oral commensals and pathobionts and provides a mechanistic basis for the variable levels of inhibitory potential observed among H2O2-producing strains of commensal oral streptococci.
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59
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Genomic and physiological insights into the lifestyle of Bifidobacterium species from water kefir. Arch Microbiol 2020; 202:1627-1637. [PMID: 32266422 DOI: 10.1007/s00203-020-01870-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/26/2020] [Accepted: 03/20/2020] [Indexed: 12/13/2022]
Abstract
Water kefir is a fermented beverage employing a natural microbial consortium, which harbours bifidobacteria, namely Bifidobacterium aquikefiri and Bifidobacterium tibiigranuli. However, little information is available on their metabolic properties or role in the consortium. In this study, we combined genomic and physiologic investigations to predict and characterize the properties of these organisms and their possible role in the consortium. When comparing the genomes of these psychrotrophic organisms with that of the three selected mesophilic probiotic Bifidobacterium strains, we could find 143 genes shared by the 3 known isolates of bifidobacteria from water kefir that do not occur in the probiotic strains. These include genes involved in acid and oxygen tolerance. In addition, their genomically predicted carbohydrate usage and transport suggest adaptation to sucrose and other plant-related sugars. Furthermore, they proved prototrophic for all amino acids in vitro, which enables them to cope with the strong amino acid limitation in water kefir.
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60
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Abstract
The catalase-negative streptococci produce as well as tolerate high levels of H2O2. This work reports the molecular mechanisms of low-H2O2-concentration-induced adaptation to higher H2O2 stress in a Streptococcus species, in which the peroxide-responsive repressor PerR and its redox regulons play the major role. Distinct from the Bacillus subtilis PerR, which is inactivated by H2O2 through histidine oxidation by the Fe2+-triggered Fenton reaction, the streptococcal PerR is inactivated by H2O2 oxidation of the structural Zn2+ binding cysteine residues and thus derepresses the expression of genes defending against oxidative stress. The reversible cysteine oxidation could provide flexibility for PerR regulation in streptococci, and the mechanism might be widely used by lactic acid bacteria, including pathogenic streptococci, containing high levels of cellular manganese, in coping with oxidative stress. The adaptation mechanism could also be applied in oral hygiene by facilitating the fitness and adaptability of the oral commensal streptococci to suppress the pathogens. Preexposure to a low concentration of H2O2 significantly increases the survivability of catalase-negative streptococci in the presence of a higher concentration of H2O2. However, the mechanisms of this adaptation remain unknown. Here, using a redox proteomics assay, we identified 57 and 35 cysteine-oxidized proteins in Streptococcus oligofermentans bacteria that were anaerobically cultured and then pulsed with 40 μM H2O2 and that were statically grown in a 40-ml culture, respectively. The oxidized proteins included the peroxide-responsive repressor PerR, the manganese uptake repressor MntR, thioredoxin system proteins Trx and Tpx, and most glycolytic proteins. Cysteine oxidations of these proteins were verified through redox Western blotting, immunoprecipitation, and liquid chromatography-tandem mass spectrometry assays. In particular, Zn2+-coordinated Cys139 and Cys142 mutations eliminated the H2O2 oxidation of PerR, and inductively coupled plasma mass spectrometry detected significantly decreased amounts of Zn2+ in H2O2-treated PerR, demonstrating that cysteine oxidation results in Zn2+ loss. An electrophoretic mobility shift assay (EMSA) determined that the DNA binding of Mn2+-bound PerR protein (PerR:Zn,Mn) was abolished by H2O2 treatment but was restored by dithiothreitol reduction, verifying that H2O2 inactivates streptococcal PerR:Zn,Mn through cysteine oxidation, analogous to the findings for MntR. Quantitative PCR and EMSA demonstrated that tpx, mntA, mntR, and dpr belonged to the PerR regulons but that only dpr was directly regulated by PerR; mntA was also controlled by MntR. Deletion of mntR significantly reduced the low-H2O2-concentration-induced adaptation of S. oligofermentans to a higher H2O2 concentration, while the absence of PerR completely abolished the self-protection. Therefore, a low H2O2 concentration resulted in the cysteine-reversible oxidations of PerR and MntR to derepress their regulons, which function in cellular metal and redox homeostasis and which endow streptococci with the antioxidative capability. This work reveals a novel Cys redox-based H2O2 defense strategy employed by catalase-negative streptococci in Mn2+-rich cellular environments. IMPORTANCE The catalase-negative streptococci produce as well as tolerate high levels of H2O2. This work reports the molecular mechanisms of low-H2O2-concentration-induced adaptation to higher H2O2 stress in a Streptococcus species, in which the peroxide-responsive repressor PerR and its redox regulons play the major role. Distinct from the Bacillus subtilis PerR, which is inactivated by H2O2 through histidine oxidation by the Fe2+-triggered Fenton reaction, the streptococcal PerR is inactivated by H2O2 oxidation of the structural Zn2+ binding cysteine residues and thus derepresses the expression of genes defending against oxidative stress. The reversible cysteine oxidation could provide flexibility for PerR regulation in streptococci, and the mechanism might be widely used by lactic acid bacteria, including pathogenic streptococci, containing high levels of cellular manganese, in coping with oxidative stress. The adaptation mechanism could also be applied in oral hygiene by facilitating the fitness and adaptability of the oral commensal streptococci to suppress the pathogens.
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61
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Wang J, Li JW, Li J, Huang Y, Wang S, Zhang JR. Regulation of pneumococcal epigenetic and colony phases by multiple two-component regulatory systems. PLoS Pathog 2020; 16:e1008417. [PMID: 32187228 PMCID: PMC7105139 DOI: 10.1371/journal.ppat.1008417] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 03/30/2020] [Accepted: 02/19/2020] [Indexed: 11/19/2022] Open
Abstract
Streptococcus pneumoniae is well known for phase variation between opaque (O) and transparent (T) colonies within clonal populations. While the O variant is specialized in invasive infection (with a thicker capsule and higher resistance to host clearance), the T counterpart possesses a relatively thinner capsule and thereby higher airway adherence and colonization. Our previous study found that phase variation is caused by reversible switches of the "opaque ON-or-OFF" methylomes or methylation patterns of pneumococcal genome, which is dominantly driven by the PsrA-catalyzed inversions of the DNA methyltransferase hsdS genes. This study revealed that switch frequency between the O and T variants is regulated by five transcriptional response regulators (rr) of the two-component systems (TCSs). The mutants of rr06, rr08, rr09, rr11 and rr14 produced significantly fewer O and more T colonies. Further mutagenesis revealed that RR06, RR08, RR09 and RR11 enrich the O variant by modulating the directions of the PsrA-catalyzed inversion reactions. In contrast, the impact of RR14 (RitR) on phase variation is independent of PsrA. Consistently, SMRT sequencing uncovered significantly diminished "opaque ON" methylome in the mutants of rr06, rr08, rr09 and rr11 but not that of rr14. Lastly, the phosphorylated form of RR11 was shown to activate the transcription of comW and two sugar utilization systems that are necessary for maintenance of the "opaque ON" genotype and phenotype. This work has thus uncovered multiple novel mechanisms that balance pneumococcal epigenetic status and physiology.
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Affiliation(s)
- Juanjuan Wang
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| | - Jing-Wen Li
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| | - Jing Li
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| | - Yijia Huang
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| | - Shaomeng Wang
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| | - Jing-Ren Zhang
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
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62
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Siwapornchai N, Lee JN, Tchalla EYI, Bhalla M, Yeoh JH, Roggensack SE, Leong JM, Bou Ghanem EN. Extracellular adenosine enhances the ability of PMNs to kill Streptococcus pneumoniae by inhibiting IL-10 production. J Leukoc Biol 2020; 108:867-882. [PMID: 32017200 DOI: 10.1002/jlb.4ma0120-115rr] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 01/14/2020] [Accepted: 01/17/2020] [Indexed: 12/18/2022] Open
Abstract
Polymorphonuclear leukocytes (PMNs) are crucial for initial control of Streptococcus pneumoniae (pneumococcus) lung infection; however, as the infection progresses their persistence in the lungs becomes detrimental. Here we explored why the antimicrobial efficacy of PMNs declines over the course of infection. We found that the progressive inability of PMNs to control infection correlated with phenotypic differences characterized by a decrease in CD73 expression, an enzyme required for production of extracellular adenosine (EAD). EAD production by CD73 was crucial for the ability of both murine and human PMNs to kill S. pneumoniae. In exploring the mechanisms by which CD73 controlled PMN function, we found that CD73 mediated its antimicrobial activity by inhibiting IL-10 production. PMNs from wild-type mice did not increase IL-10 production in response to S. pneumoniae; however, CD73-/- PMNs up-regulated IL-10 production upon pneumococcal infection in vitro and during lung challenge. IL-10 inhibited the ability of WT PMNs to kill pneumococci. Conversely, blocking IL-10 boosted the bactericidal activity of CD73-/- PMNs as well as host resistance of CD73-/- mice to pneumococcal pneumonia. CD73/IL-10 did not affect apoptosis, bacterial uptake, and intracellular killing or production of antimicrobial neutrophil elastase and myeloperoxidase. Rather, inhibition of IL-10 production by CD73 was important for optimal reactive oxygen species (ROS) production by PMNs. ROS contributed to PMN antimicrobial function as their removal or detoxification impaired the ability of PMNs to efficiently kill S. pneumoniae. This study demonstrates that CD73 controls PMN antimicrobial phenotype during S. pneumoniae infection.
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Affiliation(s)
- Nalat Siwapornchai
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - James N Lee
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Essi Y I Tchalla
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, USA
| | - Manmeet Bhalla
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, USA
| | - Jun Hui Yeoh
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, USA
| | - Sara E Roggensack
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - John M Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Elsa N Bou Ghanem
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, USA
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63
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Meng Y, Sheen CR, Magon NJ, Hampton MB, Dobson RCJ. Structure-function analyses of alkylhydroperoxidase D from Streptococcus pneumoniae reveal an unusual three-cysteine active site architecture. J Biol Chem 2020; 295:2984-2999. [PMID: 31974167 DOI: 10.1074/jbc.ra119.012226] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/19/2020] [Indexed: 12/12/2022] Open
Abstract
During aerobic growth, the Gram-positive facultative anaerobe and opportunistic human pathogen Streptococcus pneumoniae generates large amounts of hydrogen peroxide that can accumulate to millimolar concentrations. The mechanism by which this catalase-negative bacterium can withstand endogenous hydrogen peroxide is incompletely understood. The enzyme alkylhydroperoxidase D (AhpD) has been shown to contribute to pneumococcal virulence and oxidative stress responses in vivo We demonstrate here that SpAhpD exhibits weak thiol-dependent peroxidase activity and, unlike the previously reported Mycobacterium tuberculosis AhpC/D system, SpAhpD does not mediate electron transfer to SpAhpC. A 2.3-Å resolution crystal structure revealed several unusual structural features, including a three-cysteine active site architecture that is buried in a deep pocket, in contrast to the two-cysteine active site found in other AhpD enzymes. All single-cysteine SpAhpD variants remained partially active, and LC-MS/MS analyses revealed that the third cysteine, Cys-163, formed disulfide bonds with either of two cysteines in the canonical Cys-78-X-X-Cys-81 motif. We observed that SpAhpD formed a dimeric quaternary structure both in the crystal and in solution, and that the highly conserved Asn-76 of the AhpD core motif is important for SpAhpD folding. In summary, SpAhpD is a weak peroxidase and does not transfer electrons to AhpC, and therefore does not fit existing models of bacterial AhpD antioxidant defense mechanisms. We propose that it is unlikely that SpAhpD removes peroxides either directly or via AhpC, and that SpAhpD cysteine oxidation may act as a redox switch or mediate electron transfer with other thiol proteins.
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Affiliation(s)
- Yanxiang Meng
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch 8041, New Zealand
| | - Campbell R Sheen
- Callaghan Innovation, University of Canterbury, Christchurch 8041, New Zealand
| | - Nicholas J Magon
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago, Christchurch 8011, New Zealand
| | - Mark B Hampton
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago, Christchurch 8011, New Zealand.
| | - Renwick C J Dobson
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch 8041, New Zealand; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia.
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64
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Wu X, Gordon O, Jiang W, Antezana BS, Angulo-Zamudio UA, Del Rio C, Moller A, Brissac T, Tierney ARP, Warncke K, Orihuela CJ, Read TD, Vidal JE. Interaction between Streptococcus pneumoniae and Staphylococcus aureus Generates ·OH Radicals That Rapidly Kill Staphylococcus aureus Strains. J Bacteriol 2019; 201:e00474-19. [PMID: 31405914 PMCID: PMC6779455 DOI: 10.1128/jb.00474-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 08/08/2019] [Indexed: 12/26/2022] Open
Abstract
Streptococcus pneumoniae rapidly kills Staphylococcus aureus by producing membrane-permeable hydrogen peroxide (H2O2). The mechanism by which S. pneumoniae-produced H2O2 mediates S. aureus killing was investigated. An in vitro model that mimicked S. pneumoniae-S. aureus contact during colonization of the nasopharynx demonstrated that S. aureus killing required outcompeting densities of S. pneumoniae Compared to the wild-type strain, isogenic S. pneumoniae ΔlctO and S. pneumoniae ΔspxB, both deficient in production of H2O2, required increased density to kill S. aureus While residual H2O2 activity produced by single mutants was sufficient to eradicate S. aureus, an S. pneumoniae ΔspxB ΔlctO double mutant was unable to kill S. aureus A collection of 20 diverse methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) strains showed linear sensitivity (R2 = 0.95) for S. pneumoniae killing, but the same strains had different susceptibilities when challenged with pure H2O2 (5 mM). There was no association between the S. aureus clonal complex and sensitivity to either S. pneumoniae or H2O2 To kill S. aureus, S. pneumoniae produced ∼180 μM H2O2 within 4 h of incubation, while the killing-defective S. pneumoniae ΔspxB and S. pneumoniae ΔspxB ΔlctO mutants produced undetectable levels. Remarkably, a sublethal dose (1 mM) of pure H2O2 incubated with S. pneumoniae ΔspxB eradicated diverse S. aureus strains, suggesting that S. pneumoniae bacteria may facilitate conversion of H2O2 to a hydroxyl radical (·OH). Accordingly, S. aureus killing was completely blocked by incubation with scavengers of ·OH radicals, dimethyl sulfoxide (Me2SO), thiourea, or sodium salicylate. The ·OH was detected in S. pneumoniae cells by spin trapping and electron paramagnetic resonance. Therefore, S. pneumoniae produces H2O2, which is rapidly converted to a more potent oxidant, hydroxyl radicals, to rapidly intoxicate S. aureus strains.IMPORTANCEStreptococcus pneumoniae strains produce hydrogen peroxide (H2O2) to kill bacteria in the upper airways, including pathogenic Staphylococcus aureus strains. The targets of S. pneumoniae-produced H2O2 have not been discovered, in part because of a lack of knowledge about the underlying molecular mechanism. We demonstrated that an increased density of S. pneumoniae kills S. aureus by means of H2O2 produced by two enzymes, SpxB and LctO. We discovered that SpxB/LctO-produced H2O2 is converted into a hydroxyl radical (·OH) that rapidly intoxicates and kills S. aureus We successfully inhibited the toxicity of ·OH with three different scavengers and detected ·OH in the supernatant. The target(s) of the hydroxyl radicals represents a new alternative for the development of antimicrobials against S. aureus infections.
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Affiliation(s)
- Xueqing Wu
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
- Department of Infectious Disease, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Oren Gordon
- Department of Pediatrics, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Wenxin Jiang
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
| | - Brenda S Antezana
- Graduate Program in Microbiology and Molecular Genetics, Emory University, Atlanta, Georgia, USA
| | - Uriel A Angulo-Zamudio
- Regional Program for the Doctorate in Biotechnology, Faculty of Chemical Sciences Biological, Autonomous University of Sinaloa, Sinaloa, Mexico
| | - Carlos Del Rio
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
| | - Abraham Moller
- Graduate Program in Microbiology and Molecular Genetics, Emory University, Atlanta, Georgia, USA
| | - Terry Brissac
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Aimee R P Tierney
- Graduate Program in Microbiology and Molecular Genetics, Emory University, Atlanta, Georgia, USA
| | - Kurt Warncke
- Department of Physics, Emory University, Atlanta, Georgia, USA
| | - Carlos J Orihuela
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Timothy D Read
- Graduate Program in Microbiology and Molecular Genetics, Emory University, Atlanta, Georgia, USA
- Antibiotic Research Center, Emory University, Atlanta, Georgia, USA
- School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Jorge E Vidal
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
- Graduate Program in Microbiology and Molecular Genetics, Emory University, Atlanta, Georgia, USA
- Antibiotic Research Center, Emory University, Atlanta, Georgia, USA
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65
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Metabolic modulations of Pseudomonas graminis in response to H 2O 2 in cloud water. Sci Rep 2019; 9:12799. [PMID: 31488860 PMCID: PMC6728378 DOI: 10.1038/s41598-019-49319-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 07/26/2019] [Indexed: 12/26/2022] Open
Abstract
In cloud water, microorganisms are exposed to very strong stresses especially related to the presence of reactive oxygen species including H2O2 and radicals, which are the driving force of cloud chemistry. In order to understand how the bacterium Pseudomonas graminis isolated from cloud water respond to this oxidative stress, it was incubated in microcosms containing a synthetic solution of cloud water in the presence or in the absence of H2O2. P. graminis metabolome was examined by LC-MS and NMR after 50 min and after 24 hours of incubation. After 50 min, the cells were metabolizing H2O2 while this compound was still present in the medium, and it was completely biodegraded after 24 hours. Cells exposed to H2O2 had a distinct metabolome as compared to unexposed cells, revealing modulations of certain metabolic pathways in response to oxidative stress. These data indicated that the regulations observed mainly involved carbohydrate, glutathione, energy, lipid, peptides and amino-acids metabolisms. When cells had detoxified H2O2 from the medium, their metabolome was not distinguishable anymore from unexposed cells, highlighting the capacity of resilience of this bacterium. This work illustrates the interactions existing between the cloud microbial metabolome and cloud chemistry.
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66
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Imlay JA, Sethu R, Rohaun SK. Evolutionary adaptations that enable enzymes to tolerate oxidative stress. Free Radic Biol Med 2019; 140:4-13. [PMID: 30735836 PMCID: PMC6684875 DOI: 10.1016/j.freeradbiomed.2019.01.048] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 01/31/2019] [Indexed: 10/27/2022]
Abstract
Biochemical mechanisms emerged and were integrated into the metabolic plan of cellular life long before molecular oxygen accumulated in the biosphere. When oxygen levels finaly rose, they threatened specific types of enzymes: those that use organic radicals as catalysts, and those that depend upon iron centers. Nature has found ways to ensure that such enzymes are still used by contemporary organisms. In some cases they are restricted to microbes that reside in anoxic habitats, but in others they manage to function inside aerobic cells. In the latter case, it is frequently true that the ancestral enzyme has been modified to fend off poisoning. In this review we survey a range of protein adaptations that permit radical-based and low-potential iron chemistry to succeed in oxic environments. In many cases, accessory domains shield the vulnerable radical or metal center from oxygen. In others, the structures of iron cofactors evolved to less oxidizable forms, or alternative metals replaced iron altogether. The overarching view is that some classes of biochemical mechanism are intrinsically incompatible with the presence of oxygen. The structural modification of target enzymes is an under-recognized response to this problem.
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Affiliation(s)
- James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA.
| | - Ramakrishnan Sethu
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
| | - Sanjay Kumar Rohaun
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
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67
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Hydrogen peroxide release by bacteria suppresses inflammasome-dependent innate immunity. Nat Commun 2019; 10:3493. [PMID: 31375698 PMCID: PMC6677825 DOI: 10.1038/s41467-019-11169-x] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 06/26/2019] [Indexed: 12/30/2022] Open
Abstract
Hydrogen peroxide (H2O2) has a major function in host-microbial interactions. Although most studies have focused on the endogenous H2O2 produced by immune cells to kill microbes, bacteria can also produce H2O2. How microbial H2O2 influences the dynamics of host-microbial interactions is unclear. Here we show that H2O2 released by Streptococcus pneumoniae inhibits inflammasomes, key components of the innate immune system, contributing to the pathogen colonization of the host. We also show that the oral commensal H2O2-producing bacteria Streptococcus oralis can block inflammasome activation. This study uncovers an unexpected role of H2O2 in immune suppression and demonstrates how, through this mechanism, bacteria might restrain the immune system to co-exist with the host. The functions of microbial hydrogen peroxide (H2O2) in host-pathogen interactions are unclear. Here, Erttmann and Gekara show that H2O2 released by Streptococcus pneumoniae inhibits inflammasomes, and thereby contributes to the pathogen’s ability to colonize the host.
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68
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Dias O, Saraiva J, Faria C, Ramirez M, Pinto F, Rocha I. iDS372, a Phenotypically Reconciled Model for the Metabolism of Streptococcus pneumoniae Strain R6. Front Microbiol 2019; 10:1283. [PMID: 31293525 PMCID: PMC6603136 DOI: 10.3389/fmicb.2019.01283] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/23/2019] [Indexed: 11/13/2022] Open
Abstract
A high-quality GSM model for Streptococcus pneumoniae R6 model strain (iDS372), comprising 372 genes and 529 reactions, was developed. The construction of this model involved performing a genome-wide reannotation to identify the metabolic capacity of the bacterium. A reaction representing the abstraction of the biomass composition was reconciled from several studies reported in the literature and previous models, and included in the model. The final model comprises two compartments and manifold automatically generated gene rules. The validation was performed with experimental data from recent studies, regarding the usability of carbon sources, the effect of the presence of oxygen, and the requirement of amino acids for growth. This model can be used to better understand the metabolism of this major pathogen, provide clues regarding new drug targets, and eventually design strategies for fighting infections by these bacteria.
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Affiliation(s)
- Oscar Dias
- Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - João Saraiva
- Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Cristiana Faria
- Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Mario Ramirez
- Instituto de Microbiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Francisco Pinto
- BioISI – Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Isabel Rocha
- Centre of Biological Engineering, University of Minho, Braga, Portugal
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB-NOVA), Oeiras, Portugal
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69
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Kumar U, Kaviraj M, Panneerselvam P, Priya H, Chakraborty K, Swain P, Chatterjee SN, Sharma SG, Nayak PK, Nayak AK. Ascorbic acid formulation for survivability and diazotrophic efficacy of Azotobacter chroococcum Avi2 (MCC 3432) under hydrogen peroxide stress and its role in plant-growth promotion in rice (Oryza sativa L.). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 139:419-427. [PMID: 30986643 DOI: 10.1016/j.plaphy.2019.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/01/2019] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
Oxidative stress generates reactive oxygen species which causes cell damage of living organisms and are normally detoxified by antioxidants. Indirect reports signify the damages caused by reactive oxygen species and neutralized by antioxidant, but the direct evidence to confirm this hypothesis is still unclear. To validate our hypothesis, an attempt was made in a diazotrophic bacterium (Azotobacter chroococcum Avi2) as a biological system, and hydrogen peroxide (H2O2) and ascorbic acid were used as oxidative stress and antioxidant supplement, respectively. Additionally, rice plant-growth attributes by Avi2 was also assessed under H2O2 and ascorbic acid. Results indicated that higher concentration of H2O2 (2.5 mM-4.5 mM) showed the complete mortality of Avi2, whereas one ppm ascorbic acid neutralized the effect of H2O2. Turbidity, colony forming unit, DNA quantity, nifH gene abundance, indole acetic acid and ammonia productions were significantly (p < 0.5) increased by 11.93%, 17.29%, 19.80%, 74.77%, 71.89%, and 42.53%, respectively in Avi2-treated with 1.5 mM H2O2 plus ascorbic acid compared to 1.5 mM H2O2 alone. Superoxide dismutase was significantly (p < 0.5) increased by 60.85%, whereas catalase and ascorbate peroxidase activities were significantly (p < 0.05) decreased by 64.28% and 68.88% in Avi2-treated with 1.5 mM H2O2 plus ascorbic acid compared to 1.5 mM H2O2 alone. Germination percentage of three rice cultivars (FR13a, Naveen and Sahbhagi dhan) were significantly (p < 0.5) increased by 20%, 13.33%, and 4%, respectively in Avi2-treated with 0.6 mM H2O2 plus ascorbic acid compared with uninoculated control. Overall, this study indicated that ascorbic acid formulation neutralizes the H2O2-oxidative stress and enhances the survivability and plant growth-promoting efficacy of A. chroococcum Avi2 and therefore, it may be used as an effective formulation of bio-inoculants in rice under oxidative stress.
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Affiliation(s)
- Upendra Kumar
- ICAR- National Rice Research Institute, Cuttack, Odisha, 753006, India.
| | - Megha Kaviraj
- ICAR- National Rice Research Institute, Cuttack, Odisha, 753006, India
| | - P Panneerselvam
- ICAR- National Rice Research Institute, Cuttack, Odisha, 753006, India
| | - Himani Priya
- ICAR- National Rice Research Institute, Cuttack, Odisha, 753006, India
| | | | - P Swain
- ICAR- National Rice Research Institute, Cuttack, Odisha, 753006, India
| | | | - S G Sharma
- ICAR- National Rice Research Institute, Cuttack, Odisha, 753006, India
| | - P K Nayak
- ICAR- National Rice Research Institute, Cuttack, Odisha, 753006, India
| | - A K Nayak
- ICAR- National Rice Research Institute, Cuttack, Odisha, 753006, India
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70
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Gao Y, Xu W, Dou X, Wang H, Zhang X, Yang S, Liao H, Hu X, Wang H. Mitochondrial DNA Leakage Caused by Streptococcus pneumoniae Hydrogen Peroxide Promotes Type I IFN Expression in Lung Cells. Front Microbiol 2019; 10:630. [PMID: 30984149 PMCID: PMC6447684 DOI: 10.3389/fmicb.2019.00630] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 03/13/2019] [Indexed: 12/17/2022] Open
Abstract
Streptococcus pneumoniae (S. pn), the bacterial pathogen responsible for invasive pneumococcal diseases, is capable of producing substantial amounts of hydrogen peroxide. However, the impact of S. pn-secreted hydrogen peroxide (H2O2) on the host immune processes is not completely understood. Here, we demonstrated that S. pn-secreted H2O2 caused mitochondrial damage and severe histopathological damage in mouse lung tissue. Additionally, S. pn-secreted H2O2 caused not only oxidative damage to mitochondrial deoxyribonucleic acid (mtDNA), but also a reduction in the mtDNA content in alveolar epithelia cells. This resulted in the release of mtDNA into the cytoplasm, which subsequently induced type I interferons (IFN-I) expression. We also determined that stimulator of interferon genes (STING) signaling was probably involved in S. pn H2O2-inducing IFN-I expression in response to mtDNA damaged by S. pn-secreted H2O2. In conclusion, our study demonstrated that H2O2 produced by S. pn resulted in mtDNA leakage from damaged mitochondria and IFN-I production in alveolar epithelia cells, and STING may be required in this process, and this is a novel mitochondrial damage mechanism by which S. pn potentiates the IFN-I cascade in S. pn infection.
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Affiliation(s)
- Yue Gao
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, China.,School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Wenchun Xu
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, China.,School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Xiaoyun Dou
- Institute of Life Sciences, Chongqing Medical University, Chongqing, China
| | - Hong Wang
- Institute of Life Sciences, Chongqing Medical University, Chongqing, China
| | - Xuemei Zhang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, China.,School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Shenghui Yang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, China.,School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Hongyi Liao
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, China.,School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Xuexue Hu
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, China.,School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Hong Wang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, China.,School of Laboratory Medicine, Chongqing Medical University, Chongqing, China
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Abstract
ABSTRACT
Streptococcus pneumoniae
undergoes phase variation or spontaneous, reversible phenotypic variation in colony opacity, encapsulation, and pilus expression. The variation in colony opacity appears to occur in all strains, whereas the switches in the production of the capsule and pilus have been observed in several strains. This chapter elaborates on the variation in colony opacity since this phenomenon has been extensively characterized.
S. pneumoniae
produces opaque and transparent colonies on the translucent agar medium. The different colony phases are fundamentally distinct phenotypes in their metabolism and multiple characteristics, as exemplified by cell surface features and phenotypes in colonization and virulence. Opaque variants, which express more capsular polysaccharides and fewer teichoic acids, are more virulent in animal models of sepsis but colonize the nasopharynx poorly. In contrast, transparent variants, with fewer capsular polysaccharides and more teichoic acid, colonize the nasopharynx in animal models more efficiently but are relatively avirulent. Lastly, pneumococcal opacity variants are generated by differential methylation of the genome DNA variation. The reversible switch in the methylation pattern is caused by DNA inversions in three homologous
hsdS
genes of the colony opacity determinant (
cod
) or SpnD39III locus, a conserved type I restriction-modification (RM) system. The
hsdS
gene encodes the sequence recognition subunit of the type I RM DNA methyltransferase. The combination of DNA inversion and differential methylation, a complex mechanism of phase variation, generates a mixed population that may allow for the selection of organisms
in vivo
with characteristics permissive for either carriage or systemic infection.
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Kameya H, Kanazaki M, Okamoto S. Evaluation of the Effects of Reactive Oxygen Species on Growth of <i>Escherichia coli</i> by Electron Spin Resonance Spin Trapping. FOOD SCIENCE AND TECHNOLOGY RESEARCH 2019. [DOI: 10.3136/fstr.25.443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Hiromi Kameya
- Food Research Institute, National Agriculture and Food Research Organization
| | - Mika Kanazaki
- Food Research Institute, National Agriculture and Food Research Organization
| | - Susumu Okamoto
- Food Research Institute, National Agriculture and Food Research Organization
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73
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Leonard A, Lalk M. Infection and metabolism – Streptococcus pneumoniae metabolism facing the host environment. Cytokine 2018; 112:75-86. [DOI: 10.1016/j.cyto.2018.07.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 07/15/2018] [Accepted: 07/16/2018] [Indexed: 12/21/2022]
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74
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Imlay JA. Where in the world do bacteria experience oxidative stress? Environ Microbiol 2018; 21:521-530. [PMID: 30307099 DOI: 10.1111/1462-2920.14445] [Citation(s) in RCA: 179] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/02/2018] [Accepted: 10/07/2018] [Indexed: 11/26/2022]
Abstract
Reactive oxygen species - superoxide, hydrogen peroxide and hydroxyl radicals - have long been suspected of constraining bacterial growth in important microbial habitats and indeed of shaping microbial communities. Over recent decades, studies of paradigmatic organisms such as Escherichia coli, Salmonella typhimurium, Bacillus subtilis and Saccharomyces cerevisiae have pinpointed the biomolecules that oxidants can damage and the strategies by which microbes minimize their injuries. What is lacking is a good sense of the circumstances under which oxidative stress actually occurs. In this MiniReview several potential natural sources of oxidative stress are considered: endogenous ROS formation, chemical oxidation of reduced species at oxic-anoxic interfaces, H2 O2 production by lactic acid bacteria, the oxidative burst of phagocytes and the redox-cycling of secreted small molecules. While all of these phenomena can be reproduced and verified in the lab, the actual quantification of stress in natural habitats remains lacking - and, therefore, we have a fundamental hole in our understanding of the role that oxidative stress actually plays in the biosphere.
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Affiliation(s)
- James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
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75
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Chan WT, Domenech M, Moreno-Córdoba I, Navarro-Martínez V, Nieto C, Moscoso M, García E, Espinosa M. The Streptococcus pneumoniaeyefM-yoeB and relBE Toxin-Antitoxin Operons Participate in Oxidative Stress and Biofilm Formation. Toxins (Basel) 2018; 10:toxins10090378. [PMID: 30231554 PMCID: PMC6162744 DOI: 10.3390/toxins10090378] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 09/03/2018] [Accepted: 09/13/2018] [Indexed: 12/20/2022] Open
Abstract
Type II (proteic) toxin-antitoxin systems (TAs) are widely distributed among bacteria and archaea. They are generally organized as operons integrated by two genes, the first encoding the antitoxin that binds to its cognate toxin to generate a harmless protein–protein complex. Under stress conditions, the unstable antitoxin is degraded by host proteases, releasing the toxin to achieve its toxic effect. In the Gram-positive pathogen Streptococcus pneumoniae we have characterized four TAs: pezAT, relBE, yefM-yoeB, and phD-doc, although the latter is missing in strain R6. We have assessed the role of the two yefM-yoeB and relBE systems encoded by S. pneumoniae R6 by construction of isogenic strains lacking one or two of the operons, and by complementation assays. We have analyzed the phenotypes of the wild type and mutants in terms of cell growth, response to environmental stress, and ability to generate biofilms. Compared to the wild-type, the mutants exhibited lower resistance to oxidative stress. Further, strains deleted in yefM-yoeB and the double mutant lacking yefM-yoeB and relBE exhibited a significant reduction in their ability for biofilm formation. Complementation assays showed that defective phenotypes were restored to wild type levels. We conclude that these two loci may play a relevant role in these aspects of the S. pneumoniae lifestyle and contribute to the bacterial colonization of new niches.
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Affiliation(s)
- Wai Ting Chan
- i-DNA Biotechnology (M) Sdn Bhd. A-1-6 Pusat Perdagangan Kuchai, No. 2, Jalan 1/127, Kuchai Entrepreneurs Park, Kuala Lumpur 58200, Malaysia.
| | - Mirian Domenech
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain.
- CIBER de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, 28040 Madrid, Spain.
| | - Inmaculada Moreno-Córdoba
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain.
| | - Verónica Navarro-Martínez
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain.
| | - Concha Nieto
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain.
| | - Miriam Moscoso
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain.
| | - Ernesto García
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain.
- CIBER de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, 28040 Madrid, Spain.
| | - Manuel Espinosa
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain.
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76
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Redanz S, Cheng X, Giacaman RA, Pfeifer CS, Merritt J, Kreth J. Live and let die: Hydrogen peroxide production by the commensal flora and its role in maintaining a symbiotic microbiome. Mol Oral Microbiol 2018; 33:337-352. [PMID: 29897662 DOI: 10.1111/omi.12231] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2018] [Indexed: 02/05/2023]
Abstract
The majority of commensal oral streptococci are able to generate hydrogen peroxide (H2 O2 ) during aerobic growth, which can diffuse through the cell membrane and inhibit competing species in close proximity. Competing H2 O2 production is mainly dependent upon the pyruvate oxidase SpxB, and to a lesser extent the lactate oxidase LctO, both of which are important for energy generation in aerobic environments. Several studies point to a broad impact of H2 O2 production in the oral environment, including a potential role in biofilm homeostasis, signaling, and interspecies interactions. Here, we summarize the current research regarding oral streptococcal H2 O2 generation, resistance mechanisms, and the ecological impact of H2 O2 production. We also discuss the potential therapeutic utility of H2 O2 for the prevention/treatment of dysbiotic diseases as well as its potential role as a biomarker of oral health.
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Affiliation(s)
- Sylvio Redanz
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, Oregon
| | - Xingqun Cheng
- The State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,The Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Rodrigo A Giacaman
- Cariology Unit, Department of Oral Rehabilitation and Interdisciplinary Excellence Research Program on Healthy Aging (PIEI-ES), University of Talca, Talca, Chile
| | - Carmen S Pfeifer
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, Oregon
| | - Justin Merritt
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, Oregon
| | - Jens Kreth
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, Oregon
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77
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Brooks LRK, Mias GI. Streptococcus pneumoniae's Virulence and Host Immunity: Aging, Diagnostics, and Prevention. Front Immunol 2018; 9:1366. [PMID: 29988379 PMCID: PMC6023974 DOI: 10.3389/fimmu.2018.01366] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/01/2018] [Indexed: 12/14/2022] Open
Abstract
Streptococcus pneumoniae is an infectious pathogen responsible for millions of deaths worldwide. Diseases caused by this bacterium are classified as pneumococcal diseases. This pathogen colonizes the nasopharynx of its host asymptomatically, but overtime can migrate to sterile tissues and organs and cause infections. Pneumonia is currently the most common pneumococcal disease. Pneumococcal pneumonia is a global health concern and vastly affects children under the age of five as well as the elderly and individuals with pre-existing health conditions. S. pneumoniae has a large selection of virulence factors that promote adherence, invasion of host tissues, and allows it to escape host immune defenses. A clear understanding of S. pneumoniae's virulence factors, host immune responses, and examining the current techniques available for diagnosis, treatment, and disease prevention will allow for better regulation of the pathogen and its diseases. In terms of disease prevention, other considerations must include the effects of age on responses to vaccines and vaccine efficacy. Ongoing work aims to improve on current vaccination paradigms by including the use of serotype-independent vaccines, such as protein and whole cell vaccines. Extending our knowledge of the biology of, and associated host immune response to S. pneumoniae is paramount for our improvement of pneumococcal disease diagnosis, treatment, and improvement of patient outlook.
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Affiliation(s)
- Lavida R. K. Brooks
- Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
- Institute for Quantitative Health Science & Engineering, Michigan State University, East Lansing, MI, United States
| | - George I. Mias
- Institute for Quantitative Health Science & Engineering, Michigan State University, East Lansing, MI, United States
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
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78
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A Capsular Polysaccharide-Specific Antibody Alters Streptococcus pneumoniae Gene Expression during Nasopharyngeal Colonization of Mice. Infect Immun 2018; 86:IAI.00300-18. [PMID: 29735523 DOI: 10.1128/iai.00300-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 04/30/2018] [Indexed: 01/13/2023] Open
Abstract
Pneumococcal conjugate vaccines (PCV) elicit opsonophagocytic (opsonic) antibodies to pneumococcal capsular polysaccharides (PPS) and reduce nasopharyngeal (NP) colonization by vaccine-included Streptococcus pneumoniae serotypes. However, nonopsonic antibodies may also be important for protection against pneumococcal disease. For example, 1E2, a mouse IgG1 monoclonal antibody (MAb) to the serotype 3 (ST3) PPS (PPS3), reduced ST3 NP colonization in mice and altered ST3 gene expression in vitro Here, we determined whether 1E2 affects ST3 gene expression in vivo during colonization of mice by performing RNA sequencing on NP lavage fluid from ST3-infected mice treated with 1E2, a control MAb, or phosphate-buffered saline. Compared to the results for the controls, 1E2 significantly altered the expression of over 50 genes. It increased the expression of the piuBCDA operon, which encodes an iron uptake system, and decreased the expression of dpr, which encodes a protein critical for resistance to oxidative stress. 1E2-mediated effects on ST3 in vivo required divalent binding, as Fab fragments did not reduce NP colonization or alter ST3 gene expression. In vitro, 1E2 induced dose-dependent ST3 growth arrest and altered piuB and dpr expression, whereas an opsonic PPS3 MAb, 5F6, did not. 1E2-treated bacteria were more sensitive to hydrogen peroxide and the iron-requiring antibiotic streptonigrin, suggesting that 1E2 may increase iron import and enhance sensitivity to oxidative stress. Finally, 1E2 also induced rapid capsule shedding in vitro, suggesting that this may initiate 1E2-induced changes in sensitivity to oxidative stress and gene expression. Our data reveal a novel mechanism of direct, antibody-mediated antibacterial activity that could inform new directions in antipneumococcal therapy and vaccine development.
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79
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Piñas GE, Reinoso-Vizcaino NM, Yandar Barahona NY, Cortes PR, Duran R, Badapanda C, Rathore A, Bichara DR, Cian MB, Olivero NB, Perez DR, Echenique J. Crosstalk between the serine/threonine kinase StkP and the response regulator ComE controls the stress response and intracellular survival of Streptococcus pneumoniae. PLoS Pathog 2018; 14:e1007118. [PMID: 29883472 PMCID: PMC6010298 DOI: 10.1371/journal.ppat.1007118] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 06/20/2018] [Accepted: 05/23/2018] [Indexed: 11/30/2022] Open
Abstract
Streptococcus pneumoniae is an opportunistic human bacterial pathogen that usually colonizes the upper respiratory tract, but the invasion and survival mechanism in respiratory epithelial cells remains elusive. Previously, we described that acidic stress-induced lysis (ASIL) and intracellular survival are controlled by ComE through a yet unknown activation mechanism under acidic conditions, which is independent of the ComD histidine kinase that activates this response regulator for competence development at pH 7.8. Here, we demonstrate that the serine/threonine kinase StkP is essential for ASIL, and show that StkP phosphorylates ComE at Thr128. Molecular dynamic simulations predicted that Thr128-phosphorylation induces conformational changes on ComE’s DNA-binding domain. Using nonphosphorylatable (ComET128A) and phosphomimetic (ComET128E) proteins, we confirmed that Thr128-phosphorylation increased the DNA-binding affinity of ComE. The non-phosphorylated form of ComE interacted more strongly with StkP than the phosphomimetic form at acidic pH, suggesting that pH facilitated crosstalk. To identify the ComE-regulated genes under acidic conditions, a comparative transcriptomic analysis was performed between the comET128A and wt strains, and differential expression of 104 genes involved in different cellular processes was detected, suggesting that the StkP/ComE pathway induced global changes in response to acidic stress. In the comET128A mutant, the repression of spxB and sodA correlated with decreased H2O2 production, whereas the reduced expression of murN correlated with an increased resistance to cell wall antibiotic-induced lysis, compatible with cell wall alterations. In the comET128A mutant, ASIL was blocked and acid tolerance response was higher compared to the wt strain. These phenotypes, accompanied with low H2O2 production, are likely responsible for the increased survival in pneumocytes of the comET128A mutant. We propose that the StkP/ComE pathway controls the stress response, thus affecting the intracellular survival of S. pneumoniae in pneumocytes, one of the first barriers that this pathogen must cross to establish an infection. Streptococcus pneumoniae is a major human pathogen and is the causal agent of otitis (media) and sinusitis. It is also responsible for severe infections such as bacteremia, pneumonia, and meningitis, associated with 2 million annual deaths. Although this bacterium is part of the human nasopharynx commensal microbiota, it can become a pathogen and cross the epithelial cell barrier to establishing infections of varying intensity. Although S. pneumoniae is considered to be a typical extracellular pathogen, transient intracellular life forms have been found in eukaryotic cells, suggesting a putative survival mechanism. Here, we report that the serine-threonine kinase StkP was able to phosphorylate the response regulator ComE to control different cellular processes in response to environmental stress. Moreover, the phosphorylation of ComE on Thr128, and the consequent conformational and functional changes resulting from this event, extended the current knowledge of molecular activation mechanisms of response regulators. In this report, we provide evidence for the regulatory control exerted by the StkP/ComE pathway on acid-induced autolysis (associated with pneumolysin release), the acid tolerance response, and H2O2 production to modulate tissue damage and intracellular survival, which are ultimately linked to pneumococcal pathogenesis.
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Affiliation(s)
- Germán E. Piñas
- Departamento de Bioquímica Clínica—CIBICI (CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Nicolás M. Reinoso-Vizcaino
- Departamento de Bioquímica Clínica—CIBICI (CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Nubia Y. Yandar Barahona
- Departamento de Bioquímica Clínica—CIBICI (CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Paulo R. Cortes
- Departamento de Bioquímica Clínica—CIBICI (CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Rosario Duran
- Instituto Pasteur de Montevideo and Instituto de Investigaciones Biológicas Clemente Estable, Unidad de Bioquímica y Proteómica Analíticas, Montevideo, Uruguay
| | | | - Ankita Rathore
- Bioinformatics Division, Xcelris Lab Limited, Ahmedabad, India
| | | | - Melina B. Cian
- Departamento de Bioquímica Clínica—CIBICI (CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Nadia B. Olivero
- Departamento de Bioquímica Clínica—CIBICI (CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Daniel R. Perez
- Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - José Echenique
- Departamento de Bioquímica Clínica—CIBICI (CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- * E-mail:
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80
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Li X, Imlay JA. Improved measurements of scant hydrogen peroxide enable experiments that define its threshold of toxicity for Escherichia coli. Free Radic Biol Med 2018; 120:217-227. [PMID: 29550333 PMCID: PMC5940505 DOI: 10.1016/j.freeradbiomed.2018.03.025] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 03/12/2018] [Accepted: 03/13/2018] [Indexed: 01/06/2023]
Abstract
Escherichia coli is a model organism that has been exploited to reveal key details of hydrogen peroxide stress: the biomolecules that H2O2 most rapidly damages and the defensive tactics that organisms use to fend it off. Much less clear is the amount of exogenous H2O2 that is sufficient to injure the bacterium and/or to trigger its stress response. To fill this gap, we need to study the behavior of cells when they are exposed to defined amounts of H2O2 on an hours-long time scale. Such experiments are difficult because bacteria rapidly consume H2O2 that is added to test cultures. Further, lab media itself can generate H2O2, and media components interfere with the quantification of H2O2 levels. In this study we describe mechanisms by which media components interfere with H2O2 determinations, and we identify simple ways to minimize and correct for this interference. Using these techniques, it was shown that standard media generate so much H2O2 that most intracellular H2O2 derives from the medium rather than from endogenous metabolism. Indeed, bacteria spread on plates must induce their stress response or else perish. Finally, two straightforward methods were used to sustain low-micromolar steady-state concentrations of H2O2. In this way we determined that > 2 μM extracellular H2O2 is sufficient to trigger the intracellular OxyR stress response, and > 5 μM begins to impair cell growth in a minimal medium. These concentrations are orders of magnitude lower than the doses that have typically been used in lab experiments. The new approaches should enable workers to study how various organisms cope with natural levels of H2O2 stress.
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Affiliation(s)
- Xin Li
- College of Food and Bioengineering, Henan University of Science and Technology, No. 263, Kaiyuan Ave., Luoyang, Henan 471023, China.
| | - James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave., Urbana, IL 61801, USA.
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81
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Glanville DG, Han L, Maule AF, Woodacre A, Thanki D, Abdullah IT, Morrissey JA, Clarke TB, Yesilkaya H, Silvaggi NR, Ulijasz AT. RitR is an archetype for a novel family of redox sensors in the streptococci that has evolved from two-component response regulators and is required for pneumococcal colonization. PLoS Pathog 2018; 14:e1007052. [PMID: 29750817 PMCID: PMC5965902 DOI: 10.1371/journal.ppat.1007052] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 05/23/2018] [Accepted: 04/23/2018] [Indexed: 01/07/2023] Open
Abstract
To survive diverse host environments, the human pathogen Streptococcus pneumoniae must prevent its self-produced, extremely high levels of peroxide from reacting with intracellular iron. However, the regulatory mechanism(s) by which the pneumococcus accomplishes this balance remains largely enigmatic, as this pathogen and other related streptococci lack all known redox-sensing transcription factors. Here we describe a two-component-derived response regulator, RitR, as the archetype for a novel family of redox sensors in a subset of streptococcal species. We show that RitR works to both repress iron transport and enable nasopharyngeal colonization through a mechanism that exploits a single cysteine (Cys128) redox switch located within its linker domain. Biochemical experiments and phylogenetics reveal that RitR has diverged from the canonical two-component virulence regulator CovR to instead dimerize and bind DNA only upon Cys128 oxidation in air-rich environments. Atomic structures show that Cys128 oxidation initiates a "helical unravelling" of the RitR linker region, suggesting a mechanism by which the DNA-binding domain is then released to interact with its cognate regulatory DNA. Expanded computational studies indicate this mechanism could be shared by many microbial species outside the streptococcus genus.
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Affiliation(s)
- David G. Glanville
- Department of Microbiology and Immunology, Loyola University Chicago; Maywood, IL, United States of America
- MRC Centre for Molecular Bacteriology and Infection (CMBI), Imperial College London, London, United Kingdom
| | - Lanlan Han
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States of America
| | - Andrew F. Maule
- Department of Horticulture, University of Wisconsin–Madison, Linden Drive, Madison, Wisconsin, United States of America
| | - Alexandra Woodacre
- Department of Genetics, University of Leicester, Leicester, United Kingdom
| | - Devsaagar Thanki
- Department of Genetics, University of Leicester, Leicester, United Kingdom
| | - Iman Tajer Abdullah
- Department of Infection and Immunity, University of Leicester, Leicester, United Kingdom
| | - Julie A. Morrissey
- Department of Genetics, University of Leicester, Leicester, United Kingdom
| | - Thomas B. Clarke
- MRC Centre for Molecular Bacteriology and Infection (CMBI), Imperial College London, London, United Kingdom
| | - Hasan Yesilkaya
- Department of Infection and Immunity, University of Leicester, Leicester, United Kingdom
| | - Nicholas R. Silvaggi
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States of America
| | - Andrew T. Ulijasz
- Department of Microbiology and Immunology, Loyola University Chicago; Maywood, IL, United States of America
- MRC Centre for Molecular Bacteriology and Infection (CMBI), Imperial College London, London, United Kingdom
- * E-mail:
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82
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Herbert JA, Mitchell AM, Ritchie R, Ma J, Ross-Hutchinson K, Mitchell TJ. Expression of the lux genes in Streptococcus pneumoniae modulates pilus expression and virulence. PLoS One 2018; 13:e0189426. [PMID: 29342160 PMCID: PMC5771582 DOI: 10.1371/journal.pone.0189426] [Citation(s) in RCA: 2] [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: 06/26/2017] [Accepted: 11/25/2017] [Indexed: 11/18/2022] Open
Abstract
Bioluminescence has been harnessed for use in bacterial reporter systems and for in vivo imaging of infection in animal models. Strain Xen35, a bioluminescent derivative of Streptococcus pneumoniae serotype 4 strain TIGR4 was previously constructed for use for in vivo imaging of infections in animal models. We have shown that strain Xen35 is less virulent than its parent TIGR4 and that this is associated with the expression of the genes for bioluminescence. The expression of the luxA-E genes in the pneumococcus reduces virulence and down regulates the expression of the pneumococcal pilus.
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Affiliation(s)
- Jenny A. Herbert
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Andrea M. Mitchell
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Technology Hub Manager, Infrastructure and Facilities, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Ryan Ritchie
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Jiangtao Ma
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Kirsty Ross-Hutchinson
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Timothy J. Mitchell
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
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83
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Morozov GI, Porat N, Kushnir T, Najmuldeen H, Adawi A, Chalifa-Caspi V, Benisty R, Ohayon A, Liron O, Azriel S, Malka I, Dotan S, Portnoi M, Piotrowski AA, Kafka D, Hajaj B, Fishilevich T, Shagan M, Tal M, Ellis R, Morrison DA, Mitchell AM, Mitchell TJ, Dagan R, Yesilkaya H, Nebenzahl YM. Flavin Reductase Contributes to Pneumococcal Virulence by Protecting from Oxidative Stress and Mediating Adhesion and Elicits Protection Against Pneumococcal Challenge. Sci Rep 2018; 8:314. [PMID: 29321514 PMCID: PMC5762878 DOI: 10.1038/s41598-017-18645-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 11/01/2017] [Indexed: 12/26/2022] Open
Abstract
Pneumococcal flavin reductase (FlaR) is known to be cell-wall associated and possess age dependent antigenicity in children. This study aimed at characterizing FlaR and elucidating its involvement in pneumococcal physiology and virulence. Bioinformatic analysis of FlaR sequence identified three-conserved cysteine residues, suggesting a transition metal-binding capacity. Recombinant FlaR (rFlaR) bound Fe2+ and exhibited FAD-dependent NADP-reductase activity, which increased in the presence of cysteine or excess Fe2+ and inhibited by divalent-chelating agents. flaR mutant was highly susceptible to H2O2 compared to its wild type (WT) and complemented strains, suggesting a role for FlaR in pneumococcal oxidative stress resistance. Additionally, flaR mutant demonstrated significantly decreased mice mortality following intraperitoneal infection. Interestingly, lack of FlaR did not affect the extent of phagocytosis by primary mouse peritoneal macrophages but reduced adhesion to A549 cells compared to the WT and complemented strains. Noteworthy are the findings that immunization with rFlaR elicited protection in mice against intraperitoneal lethal challenge and anti-FlaR antisera neutralized bacterial virulence. Taken together, FlaR's roles in pneumococcal physiology and virulence, combined with its lack of significant homology to human proteins, point towards rFlaR as a vaccine candidate.
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Affiliation(s)
- Giora I Morozov
- The Shraga Segal Department of Microbiology and Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Nurith Porat
- The Shraga Segal Department of Microbiology and Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,Pediatric Infectious Disease Unit, Soroka University Medical Center, Beer Sheva, Israel
| | - Tatyana Kushnir
- The Shraga Segal Department of Microbiology and Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Hastyar Najmuldeen
- Department of Infection, Immunity & Inflammation, University of Leicester, Leicester, United Kingdom.,Department of Biology, College of Science, University of Sulaimani, Sulaymaniyah, Iraq
| | - Asad Adawi
- The Shraga Segal Department of Microbiology and Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Vered Chalifa-Caspi
- National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Rachel Benisty
- The Shraga Segal Department of Microbiology and Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,Pediatric Infectious Disease Unit, Soroka University Medical Center, Beer Sheva, Israel
| | - Ariel Ohayon
- The Shraga Segal Department of Microbiology and Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | | | - Shalhevet Azriel
- The Shraga Segal Department of Microbiology and Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Itai Malka
- The Shraga Segal Department of Microbiology and Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | | | | | - Andrew A Piotrowski
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | | | - Barak Hajaj
- The Shraga Segal Department of Microbiology and Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,Pediatric Infectious Disease Unit, Soroka University Medical Center, Beer Sheva, Israel
| | - Tali Fishilevich
- The Shraga Segal Department of Microbiology and Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Marilou Shagan
- The Shraga Segal Department of Microbiology and Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | | | | | - Donald A Morrison
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Andrea M Mitchell
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Timothy J Mitchell
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Ron Dagan
- Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Hasan Yesilkaya
- Department of Infection, Immunity & Inflammation, University of Leicester, Leicester, United Kingdom
| | - Yaffa Mizrachi Nebenzahl
- The Shraga Segal Department of Microbiology and Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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84
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Anderson R, Feldman C. Review manuscript: Mechanisms of platelet activation by the pneumococcus and the role of platelets in community-acquired pneumonia. J Infect 2017; 75:473-485. [PMID: 28943342 DOI: 10.1016/j.jinf.2017.09.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/13/2017] [Accepted: 09/15/2017] [Indexed: 12/11/2022]
Abstract
There is increasing recognition of the involvement of platelets in orchestrating inflammatory responses, driving the activation of neutrophils, monocytes and vascular endothelium, which, if poorly controlled, may lead to microvascular dysfunction. Importantly, hyperreactivity of platelets has been implicated in the pathogenesis of myocardial injury and the associated particularly high prevalence of acute cardiovascular events in patients with severe community-acquired pneumonia (CAP), of which Streptococcus pneumoniae (pneumococcus) is the most commonly encountered aetiologic agent. In this context, it is noteworthy that a number of studies have documented various mechanisms by which the pneumococcus may directly promote platelet aggregation and activation. The major contributors to platelet activation include several different types of pneumococcal adhesin, the pore-forming toxin, pneumolysin, and possibly pathogen-derived hydrogen peroxide, which collectively represent a major focus of the current review. This is followed by an overview of the limited experimental studies together with a larger series of clinical studies mainly focused on all-cause CAP, which have provided evidence in support of associations between alterations in circulating platelet counts, most commonly thrombocytopenia, and a poor clinical outcome. The final section of the review covers, albeit briefly, systemic biomarkers of platelet activation which may have prognostic potential.
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Affiliation(s)
- Ronald Anderson
- Department of Immunology and Institute for Cellular and Molecular Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa.
| | - Charles Feldman
- Division of Pulmonology, Department of Internal Medicine, Charlotte Maxeke Johannesburg Academic Hospital and Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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85
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Wang P, Lee Y, Igo MM, Roper MC. Tolerance to oxidative stress is required for maximal xylem colonization by the xylem-limited bacterial phytopathogen, Xylella fastidiosa. MOLECULAR PLANT PATHOLOGY 2017; 18:990-1000. [PMID: 27377476 PMCID: PMC6638236 DOI: 10.1111/mpp.12456] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 06/24/2016] [Accepted: 06/28/2016] [Indexed: 05/07/2023]
Abstract
Bacterial plant pathogens often encounter reactive oxygen species (ROS) during host invasion. In foliar bacterial pathogens, multiple regulatory proteins are involved in the sensing of oxidative stress and the activation of the expression of antioxidant genes. However, it is unclear whether xylem-limited bacteria, such as Xylella fastidiosa, experience oxidative stress during the colonization of plants. Examination of the X. fastidiosa genome uncovered only one homologue of oxidative stress regulatory proteins, OxyR. Here, a knockout mutation in the X. fastidiosa oxyR gene was constructed; the resulting strain was significantly more sensitive to hydrogen peroxide (H2 O2 ) relative to the wild-type. In addition, during early stages of grapevine infection, the survival rate was 1000-fold lower for the oxyR mutant than for the wild-type. This supports the hypothesis that grapevine xylem represents an oxidative environment and that X. fastidiosa must overcome this challenge to achieve maximal xylem colonization. Finally, the oxyR mutant exhibited reduced surface attachment and cell-cell aggregation and was defective in biofilm maturation, suggesting that ROS could be a potential environmental cue stimulating biofilm development during the early stages of host colonization.
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Affiliation(s)
- Peng Wang
- Department of Plant Pathology and MicrobiologyUniversity of CaliforniaRiversideCA92521USA
| | - Yunho Lee
- Department of Microbiology and Molecular GeneticsUniversity of CaliforniaDavisCA95616USA
| | - Michele M. Igo
- Department of Microbiology and Molecular GeneticsUniversity of CaliforniaDavisCA95616USA
| | - M. Caroline Roper
- Department of Plant Pathology and MicrobiologyUniversity of CaliforniaRiversideCA92521USA
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86
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Escherichia coli cytochrome c peroxidase is a respiratory oxidase that enables the use of hydrogen peroxide as a terminal electron acceptor. Proc Natl Acad Sci U S A 2017; 114:E6922-E6931. [PMID: 28696311 DOI: 10.1073/pnas.1701587114] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Microbial cytochrome c peroxidases (Ccp) have been studied for 75 years, but their physiological roles are unclear. Ccps are located in the periplasms of bacteria and the mitochondrial intermembrane spaces of fungi. In this study, Ccp is demonstrated to be a significant degrader of hydrogen peroxide in anoxic Escherichia coli Intriguingly, ccp transcription requires both the presence of H2O2 and the absence of O2 Experiments show that Ccp lacks enough activity to shield the cytoplasm from exogenous H2O2 However, it receives electrons from the quinone pool, and its flux rate approximates flow to other anaerobic electron acceptors. Indeed, Ccp enabled E. coli to grow on a nonfermentable carbon source when H2O2 was supplied. Salmonella behaved similarly. This role rationalizes ccp repression in oxic environments. We speculate that micromolar H2O2 is created both biologically and abiotically at natural oxic/anoxic interfaces. The OxyR response appears to exploit this H2O2 as a terminal oxidant while simultaneously defending the cell against its toxicity.
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87
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Li T, Xu M, Zheng L. Is SpxA2 involved in hydrogen peroxide production and competence development in Streptococcus sanguinis? J Med Microbiol 2017; 66:981-989. [PMID: 28693663 DOI: 10.1099/jmm.0.000506] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE The objective of the present study was to investigate whether Streptococcus sanguinis SpxA2 plays a role in competence development and endogenous H2O2 generation, and whether the SpxA2 Cys10-XX-Cys13 (CXXC) motif is involved in competence development. METHODOLOGY The competence development of wild-type S. sanguinis (SK36) and its derivatives was compared by transformation efficiency assay and real-time RT-PCR. The spx allele mutants, spxA2 (C10A) and spxA2 (C13A), were constructed by site-directed mutagenesis. The Δpox mutant was treated with 1 mM H2O2 to exclude the effect of other Pox products on competence development. RESULTS Compared with the wild-type (4.42±0.58×10-4), the ΔspxA2 mutant showed decreased transformation efficiency (0.07±0.03×10-4). Furthermore, there was a 2- to 15-fold reduction in ΔspxA2 mutant com gene expression. SpxA2 was able to down-regulate endogenous H2O2 generation by repressing pox expression. Additionally, endogenous H2O2 negatively regulated competence without affecting spxA2 expression. The Δpox mutant increased com gene expression (2- to 8-fold), but the 1 mM H2O2-treated Δpox mutant showed decreased com gene expression. Interestingly, the ΔspxA2Δpox mutant showed enhanced competence-associated parameters. The fact that spxA2 (C10A) and spxA2 (C13A) behaved like the ΔspxA2 mutant revealed the role of the CXXC motif in competence development. CONCLUSION Although the intricate relationship between SpxA2, pox-mediated H2O2 production and competence development was clarified in S. sanguinis, it would be worthwhile to explore further whether H2O2 is involved in competence development through oxidizing the SpxA2 CXXC motif.
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Affiliation(s)
- Ting Li
- Department of Microbiology and Parasitology, College of Basic Medical Science, China Medical University, No. 77 Puhe Road, Shenyang 110122, Liaoning Province, PR China
| | - Mengya Xu
- Department of Microbiology and Parasitology, College of Basic Medical Science, China Medical University, No. 77 Puhe Road, Shenyang 110122, Liaoning Province, PR China
| | - Lanyan Zheng
- Department of Microbiology and Parasitology, College of Basic Medical Science, China Medical University, No. 77 Puhe Road, Shenyang 110122, Liaoning Province, PR China
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88
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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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89
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Brown LR, Caulkins RC, Schartel TE, Rosch JW, Honsa ES, Schultz-Cherry S, Meliopoulos VA, Cherry S, Thornton JA. Increased Zinc Availability Enhances Initial Aggregation and Biofilm Formation of Streptococcus pneumoniae. Front Cell Infect Microbiol 2017. [PMID: 28638805 PMCID: PMC5461340 DOI: 10.3389/fcimb.2017.00233] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Bacteria growing within biofilms are protected from antibiotics and the immune system. Within these structures, horizontal transfer of genes encoding virulence factors, and promoting antibiotic resistance occurs, making biofilms an extremely important aspect of pneumococcal colonization and persistence. Identifying environmental cues that contribute to the formation of biofilms is critical to understanding pneumococcal colonization and infection. Iron has been shown to be essential for the formation of pneumococcal biofilms; however, the role of other physiologically important metals such as copper, zinc, and manganese has been largely neglected. In this study, we investigated the effect of metals on pneumococcal aggregation and early biofilm formation. Our results show that biofilms increase as zinc concentrations increase. The effect was found to be zinc-specific, as altering copper and manganese concentrations did not affect biofilm formation. Scanning electron microscopy analysis revealed structural differences between biofilms grown in varying concentrations of zinc. Analysis of biofilm formation in a mutant strain lacking the peroxide-generating enzyme pyruvate oxidase, SpxB, revealed that zinc does not protect against pneumococcal H2O2. Further, analysis of a mutant strain lacking the major autolysin, LytA, indicated the role of zinc as a negative regulator of LytA-dependent autolysis, which could affect biofilm formation. Additionally, analysis of cell-cell aggregation via plating and microscopy revealed that high concentrations of zinc contribute to intercellular interaction of pneumococci. The findings from this study demonstrate that metal availability contributes to the ability of pneumococci to form aggregates and subsequently, biofilms.
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Affiliation(s)
- Lindsey R Brown
- Department of Biological Sciences, Mississippi State UniversityStarkville, MS, United States
| | - Rachel C Caulkins
- Department of Biological Sciences, Mississippi State UniversityStarkville, MS, United States
| | - Tyler E Schartel
- Department of Biological Sciences, Mississippi State UniversityStarkville, MS, United States
| | - Jason W Rosch
- Department of Infectious Diseases, St. Jude Children's Research HospitalMemphis, TN, United States
| | - Erin S Honsa
- Department of Infectious Diseases, St. Jude Children's Research HospitalMemphis, TN, United States
| | - Stacey Schultz-Cherry
- Department of Infectious Diseases, St. Jude Children's Research HospitalMemphis, TN, United States
| | - Victoria A Meliopoulos
- Department of Infectious Diseases, St. Jude Children's Research HospitalMemphis, TN, United States
| | - Sean Cherry
- Department of Infectious Diseases, St. Jude Children's Research HospitalMemphis, TN, United States
| | - Justin A Thornton
- Department of Biological Sciences, Mississippi State UniversityStarkville, MS, United States
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90
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Hajaj B, Yesilkaya H, Shafeeq S, Zhi X, Benisty R, Tchalah S, Kuipers OP, Porat N. CodY Regulates Thiol Peroxidase Expression as Part of the Pneumococcal Defense Mechanism against H 2O 2 Stress. Front Cell Infect Microbiol 2017; 7:210. [PMID: 28596944 PMCID: PMC5443158 DOI: 10.3389/fcimb.2017.00210] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Accepted: 05/09/2017] [Indexed: 12/21/2022] Open
Abstract
Streptococcus pneumoniae is a facultative anaerobic pathogen. Although it maintains fermentative metabolism, during aerobic growth pneumococci produce high levels of H2O2, which can have adverse effects on cell viability and DNA, and influence pneumococcal interaction with its host. The pneumococcus is unusual in its dealing with toxic reactive oxygen species (ROS) in that it neither has catalase nor the global regulators of peroxide stress resistance. Previously, we identified pneumococcal thiol peroxidase (TpxD) as the key enzyme for enzymatic removal of H2O2, and showed that TpxD synthesis is up-regulated upon exposure to H2O2. This study aimed to reveal the mechanism controlling TpxD expression under H2O2 stress. We hypothesize that H2O2 activates a transcription factor which in turn up-regulates tpxD expression. Microarray analysis revealed a pneumococcal global transcriptional response to H2O2. Mutation of tpxD abolished H2O2-mediated response to high H2O2 levels, signifying the need for an active TpxD under oxidative stress conditions. Bioinformatic tools, applied to search for a transcription factor modulating tpxD expression, pointed toward CodY as a potential candidate. Indeed, a putative 15-bp consensus CodY binding site was found in the proximal region of tpxD-coding sequence. Binding of CodY to this site was confirmed by EMSA, and genetic engineering techniques demonstrated that this site is essential for TpxD up-regulation under H2O2 stress. Furthermore, tpxD expression was reduced in a ΔcodY mutant. These data indicate that CodY is an activator of tpxD expression, triggering its up-regulation under H2O2 stress. In addition we show that H2O2 specifically oxidizes the 2 CodY cysteines. This oxidation may trigger a conformational change in CodY, resulting in enhanced binding to DNA. A schematic model illustrating the contribution of TpxD and CodY to pneumococcal global transcriptional response to H2O2 is proposed.
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Affiliation(s)
- Barak Hajaj
- Pediatric Infectious Disease Unit, Department of Microbiology and Immunology, Faculty of Health Sciences, Soroka University Medical Center, Ben-Gurion University of the NegevBeer Sheva, Israel
| | - Hasan Yesilkaya
- Department of Infection, Immunity and Inflammation, University of LeicesterLeicester, United Kingdom
| | - Sulman Shafeeq
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of GroningenGroningen, Netherlands
| | - Xiangyun Zhi
- Department of Infection, Immunity and Inflammation, University of LeicesterLeicester, United Kingdom
| | - Rachel Benisty
- Pediatric Infectious Disease Unit, Department of Microbiology and Immunology, Faculty of Health Sciences, Soroka University Medical Center, Ben-Gurion University of the NegevBeer Sheva, Israel
| | - Shiran Tchalah
- Pediatric Infectious Disease Unit, Department of Microbiology and Immunology, Faculty of Health Sciences, Soroka University Medical Center, Ben-Gurion University of the NegevBeer Sheva, Israel
| | - Oscar P Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of GroningenGroningen, Netherlands
| | - Nurith Porat
- Pediatric Infectious Disease Unit, Department of Microbiology and Immunology, Faculty of Health Sciences, Soroka University Medical Center, Ben-Gurion University of the NegevBeer Sheva, Israel
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91
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Martin JE, Lisher JP, Winkler ME, Giedroc DP. Perturbation of manganese metabolism disrupts cell division in Streptococcus pneumoniae. Mol Microbiol 2017; 104:334-348. [PMID: 28127804 DOI: 10.1111/mmi.13630] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2017] [Indexed: 12/30/2022]
Abstract
Manganese (Mn) is an essential micronutrient and required cofactor in bacteria. Despite its importance, excess Mn can impair bacterial growth, the mechanism of which remains largely unexplored. Here, we show that proper Mn homeostasis is critical for cellular growth of the major human respiratory pathogen Streptococcus pneumoniae. Perturbations in Mn homeostasis genes, psaBCA, encoding the Mn importer, and mntE, encoding the Mn exporter, lead to Mn sensitivity during aerobiosis. Mn-stressed cells accumulate iron and copper, in addition to Mn. Impaired growth is a direct result of Mn toxicity and does not result from iron-mediated Fenton chemistry, since cells remain sensitive to Mn during anaerobiosis or when hydrogen peroxide biogenesis is significantly reduced. Mn-stressed cells are significantly elongated, whereas Mn-limitation imposed by zinc addition leads to cell shortening. We show that Mn accumulation promotes aberrant dephosphorylation of cell division proteins via hyperactivation of the Mn-dependent protein phosphatase PhpP, a key enzyme involved in the regulation of cell division. We discuss a mechanism by which cellular Mn:Zn ratios dictate PhpP specific activity thereby regulating pneumococcal cell division. We propose that Mn-metalloenzymes are particularly susceptible to hyperactivation or mismetallation, suggesting the need for exquisite cellular control of Mn-dependent metabolic processes.
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Affiliation(s)
- Julia E Martin
- Department of Chemistry, Indiana University, Bloomington, IN, 47405-7102, USA
| | - John P Lisher
- Department of Chemistry, Indiana University, Bloomington, IN, 47405-7102, USA.,Graduate Program in Biochemistry Indiana University, Bloomington, IN, 47405, USA
| | - Malcolm E Winkler
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA.,Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, 47405, USA
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, IN, 47405-7102, USA.,Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, 47405, USA
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92
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Chen Z, Wang X, Yang F, Hu Q, Tong H, Dong X. Molecular Insights into Hydrogen Peroxide-sensing Mechanism of the Metalloregulator MntR in Controlling Bacterial Resistance to Oxidative Stresses. J Biol Chem 2017; 292:5519-5531. [PMID: 28223356 DOI: 10.1074/jbc.m116.764126] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 01/28/2017] [Indexed: 11/06/2022] Open
Abstract
Manganese contributes to anti-oxidative stress particularly in catalase-devoid bacteria, and DtxR family metalloregulators, through sensing cellular Mn2+ content, regulate its homeostasis. Here, we show that metalloregulator MntR (So-MntR) functions dually as Mn2+ and H2O2 sensors in mediating H2O2 resistance by an oral streptococcus. H2O2 disrupted So-MntR binding to Mn2+ transporter mntABC promoter and induced disulfide-linked dimerization of the protein. Mass spectrometry identified Cys-11/Cys-156 and Cys-11/Cys-11 disulfide-linked peptides in H2O2-treated So-MntR. Site mutagenesis of Cys-11 and Cys-156 and particularly Cys-11 abolished H2O2-induced disulfide-linked dimers and weakened H2O2 damage on So-MntR binding, indicating that H2O2 inactivates So-MntR via disulfide-linked dimerization. So-MntR C123S mutant was extremely sensitive to H2O2 oxidization in dimerization/oligomerization, probably because the mutagenesis caused a conformational change that facilitates Cys-11/Cys-156 disulfide linkage. Intermolecular Cys-11/Cys-11 disulfide was detected in C123S/C156S double mutant. Redox Western blot detected So-MntR oligomers in air-exposed cells but remarkably decreased upon H2O2 pulsing, suggesting a proteolysis of the disulfide-linked So-MntR oligomers. Remarkably, elevated C11S and C156S but much lower C123S proteins were detected in H2O2-pulsed cells, confirming Cys-11 and Cys-156 contributed to H2O2-induced oligomerization and degradation. Accordingly, in the C11S and C156S mutants, expression of mntABC and cellular Mn2+ decreased, but H2O2 susceptibility increased. In the C123S mutant, increased mntABC expression, cellular Mn2+ content, and manganese-mediated H2O2 survival were determined. Given the wide distribution of Cys-11 in streptococcal DtxR-like metalloregulators, the disclosed redox regulatory function and mechanism of So-MntR can be employed by the DtxR family proteins in bacterial resistance to oxidative stress.
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Affiliation(s)
- Zhaoyuan Chen
- From the State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, China.,School of Life Sciences, University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing 100049, China, and
| | - Xinhui Wang
- From the State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, China.,School of Life Sciences, University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing 100049, China, and
| | - Fan Yang
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qingqing Hu
- From the State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, China.,School of Life Sciences, University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing 100049, China, and
| | - Huichun Tong
- From the State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, China, .,School of Life Sciences, University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing 100049, China, and
| | - Xiuzhu Dong
- From the State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, China, .,School of Life Sciences, University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, Beijing 100049, China, and
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93
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Sumioka R, Nakata M, Okahashi N, Li Y, Wada S, Yamaguchi M, Sumitomo T, Hayashi M, Kawabata S. Streptococcus sanguinis induces neutrophil cell death by production of hydrogen peroxide. PLoS One 2017; 12:e0172223. [PMID: 28222125 PMCID: PMC5319702 DOI: 10.1371/journal.pone.0172223] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 02/01/2017] [Indexed: 11/18/2022] Open
Abstract
Streptococcus is the dominant bacterial genus in the human oral cavity and a leading cause of infective endocarditis. Streptococcus sanguinis belongs to the mitis group of streptococci and produces hydrogen peroxide (H2O2) by the action of SpxB, a pyruvate oxidase. In this study, we investigated the involvement of SpxB in survival of S. sanguinis in human blood and whether bacterial H2O2 exhibits cytotoxicity against human neutrophils. Results of a bactericidal test with human whole blood revealed that the spxB mutation in S. sanguinis is detrimental to its survival in blood. When S. sanguinis strains were exposed to isolated neutrophils, the bacterial survival rate was significantly decreased by spxB deletion. Furthermore, human neutrophils exposed to the S. sanguinis wild-type strain, in contrast to those exposed to an spxB mutant strain, underwent cell death with chromatin de-condensation and release of web-like extracellular DNA, reflecting induction of neutrophil extracellular traps (NETs). Since reactive oxygen species-mediated NET induction requires citrullination of arginine residues in histone proteins and subsequent chromatin de-condensation, we examined citrullination levels of histone in infected neutrophils. It is important to note that the citrullinated histone H3 was readily detected in neutrophils infected with the wild-type strain, as compared to infection with the spxB mutant strain. Moreover, decomposition of streptococcal H2O2 with catalase reduced NET induction. These results suggest that H2O2 produced by S. sanguinis provokes cell death of neutrophils and NET formation, thus potentially affecting bacterial survival in the bloodstream.
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Affiliation(s)
- Ryuichi Sumioka
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita-Osaka, Japan
- Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita-Osaka, Japan
| | - Masanobu Nakata
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita-Osaka, Japan
- * E-mail:
| | - Nobuo Okahashi
- Center for Frontier Oral Science, Osaka University Graduate School of Dentistry, Suita-Osaka, Japan
| | - Yixuan Li
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita-Osaka, Japan
| | - Satoshi Wada
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita-Osaka, Japan
| | - Masaya Yamaguchi
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita-Osaka, Japan
| | - Tomoko Sumitomo
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita-Osaka, Japan
| | - Mikako Hayashi
- Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita-Osaka, Japan
| | - Shigetada Kawabata
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita-Osaka, Japan
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94
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Turner AG, Ong CLY, Walker MJ, Djoko KY, McEwan AG. Transition Metal Homeostasis in Streptococcus pyogenes and Streptococcus pneumoniae. Adv Microb Physiol 2017; 70:123-191. [PMID: 28528647 DOI: 10.1016/bs.ampbs.2017.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Trace metals such as Fe, Mn, Zn and Cu are essential for various biological functions including proper innate immune function. The host immune system has complicated and coordinated mechanisms in place to either starve and/or overload invading pathogens with various metals to combat the infection. Here, we discuss the roles of Fe, Mn and Zn in terms of nutritional immunity, and also the roles of Cu and Zn in metal overload in relation to the physiology and pathogenesis of two human streptococcal species, Streptococcus pneumoniae and Streptococcus pyogenes. S. pneumoniae is a major human pathogen that is carried asymptomatically in the nasopharynx by up to 70% of the population; however, transition to internal sites can cause a range of diseases such as pneumonia, otitis media, meningitis and bacteraemia. S. pyogenes is a human pathogen responsible for diseases ranging from pharyngitis and impetigo, to severe invasive infections. Both species have overlapping capacity with respect to metal acquisition, export and regulation and how metal homeostasis relates to their virulence and ability to invade and survive within the host. It is becoming more apparent that metals have an important role to play in the control of infection, and with further investigations, it could lead to the potential use of metals in novel antimicrobial therapies.
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Affiliation(s)
- Andrew G Turner
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Cheryl-Lynn Y Ong
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Mark J Walker
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Karrera Y Djoko
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Alastair G McEwan
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia.
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95
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Otoupal PB, Erickson KE, Escalas-Bordoy A, Chatterjee A. CRISPR Perturbation of Gene Expression Alters Bacterial Fitness under Stress and Reveals Underlying Epistatic Constraints. ACS Synth Biol 2017; 6:94-107. [PMID: 27529436 DOI: 10.1021/acssynbio.6b00050] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The evolution of antibiotic resistance has engendered an impending global health crisis that necessitates a greater understanding of how resistance emerges. The impact of nongenetic factors and how they influence the evolution of resistance is a largely unexplored area of research. Here we present a novel application of CRISPR-Cas9 technology for investigating how gene expression governs the adaptive pathways available to bacteria during the evolution of resistance. We examine the impact of gene expression changes on bacterial adaptation by constructing a library of deactivated CRISPR-Cas9 synthetic devices to tune the expression of a set of stress-response genes in Escherichia coli. We show that artificially inducing perturbations in gene expression imparts significant synthetic control over fitness and growth during stress exposure. We present evidence that these impacts are reversible; strains with synthetically perturbed gene expression regained wild-type growth phenotypes upon stress removal, while maintaining divergent growth characteristics under stress. Furthermore, we demonstrate a prevailing trend toward negative epistatic interactions when multiple gene perturbations are combined simultaneously, thereby posing an intrinsic constraint on gene expression underlying adaptive trajectories. Together, these results emphasize how CRISPR-Cas9 can be employed to engineer gene expression changes that shape bacterial adaptation, and present a novel approach to synthetically control the evolution of antimicrobial resistance.
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Affiliation(s)
- Peter B. Otoupal
- Department
of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, United States
| | - Keesha E. Erickson
- Department
of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, United States
| | - Antoni Escalas-Bordoy
- Department
of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, United States
| | - Anushree Chatterjee
- Department
of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, United States
- BioFrontiers
Institute, University of Colorado at Boulder, Boulder, Colorado 80309, United States
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96
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Knaus UG, Hertzberger R, Pircalabioru GG, Yousefi SPM, Branco dos Santos F. Pathogen control at the intestinal mucosa - H 2O 2 to the rescue. Gut Microbes 2017; 8:67-74. [PMID: 28080210 PMCID: PMC5341913 DOI: 10.1080/19490976.2017.1279378] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Intestinal infections are a global challenge, connected to malnutrition and inadequate hygiene in developing countries, and to expanding antibiotic resistance in developed countries. In general, a healthy host is capable of fighting off gut pathogens or at least to recover from infections quickly. The underlying protective mechanism, termed colonization resistance, is provided by indigenous commensal communities (microbiota) that are shaped and aided by the host's epithelial and innate immune system. Commensal-pathogen interactions are governed by competition for a suitable niche for replication and stable colonization, nutrient availability, species-specific alterations of the metabolic environment, changes in oxygen tension and release of chemicals and proteinaceous toxins (bacteriocins). This protective intestinal milieu is further reinforced by antimicrobial factors and chemicals secreted by the epithelial barrier, by dendritic cell sensing and by homeostasis between T-cell subsets (Treg/Th17) in the lamina propria. The 3 players (host-microbiota-pathogen) communicate via direct interactions or secreted factors. Our recent manuscript illustrates that reactive oxygen species (ROS) are an integral part of colonization resistance and should be considered an interkingdom antivirulence strategy.
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Affiliation(s)
- Ulla G. Knaus
- Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland
| | - Rosanne Hertzberger
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | | | - S. Parsa M. Yousefi
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
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97
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Van Acker H, Coenye T. The Role of Reactive Oxygen Species in Antibiotic-Mediated Killing of Bacteria. Trends Microbiol 2017; 25:456-466. [PMID: 28089288 DOI: 10.1016/j.tim.2016.12.008] [Citation(s) in RCA: 347] [Impact Index Per Article: 49.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/09/2016] [Accepted: 12/15/2016] [Indexed: 11/26/2022]
Abstract
Recently, it was proposed that there is a common mechanism behind the activity of bactericidal antibiotics, involving the production of reactive oxygen species (ROS). However, the involvement of ROS in antibiotic-mediated killing has become the subject of much debate. In the present review, we provide an overview of the data supporting the ROS hypothesis; we also present data that explain the contradictory results often obtained when studying antibiotic-induced ROS production. For this latter aspect we will focus on the importance of taking the experimental setup into consideration and on the importance of some technical aspects of the assays typically used. Finally, we discuss the link between ROS production and toxin-antitoxin modules, and present an overview of implications for treatment.
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Affiliation(s)
- Heleen Van Acker
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium.
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98
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Brito L, Wilton J, Ferrándiz MJ, Gómez-Sanz A, de la Campa AG, Amblar M. Absence of tmRNA Has a Protective Effect against Fluoroquinolones in Streptococcus pneumoniae. Front Microbiol 2017; 7:2164. [PMID: 28119681 PMCID: PMC5222879 DOI: 10.3389/fmicb.2016.02164] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 12/23/2016] [Indexed: 11/13/2022] Open
Abstract
The transfer messenger RNA (tmRNA), encoded by the ssrA gene, is a small non-coding RNA involved in trans-translation that contributes to the recycling of ribosomes stalled on aberrant mRNAs. In most bacteria, its inactivation has been related to a decreased ability to respond to and recover from a variety of stress conditions. In this report, we investigated the role of tmRNA in stress adaptation in the human pathogen Streptococcus pneumoniae. We constructed a tmRNA deletion mutant and analyzed its response to several lethal stresses. The ΔssrA strain grew slower than the wild type, indicating that, although not essential, tmRNA is important for normal pneumococcal growth. Moreover, deletion of tmRNA increased susceptibility to UV irradiation, to exogenous hydrogen peroxide and to antibiotics that inhibit protein synthesis and transcription. However, the ΔssrA strain was more resistant to fluoroquinolones, showing twofold higher MIC values and up to 1000-fold higher survival rates than the wild type. Deletion of SmpB, the other partner in trans-translation, also reduced survival to levofloxacin in a similar extent. Accumulation of intracellular reactive oxygen species associated to moxifloxacin and levofloxacin treatment was also highly reduced (∼100-fold). Nevertheless, the ΔssrA strain showed higher intracellular accumulation of ethidium bromide and levofloxacin than the wild type, suggesting that tmRNA deficiency protects pneumococcal cells from fluoroquinolone-mediated killing. In fact, analysis of chromosome integrity revealed that deletion of tmRNA prevented the fragmentation of the chromosome associated to levofloxacin treatment. Moreover, such protective effect appears to relay mainly on inhibition of protein synthesis, since a similar effect was observed with antibiotics that inhibit that process. The emergence and spread of drug-resistant pneumococci is a matter of concern and these results contribute to a better comprehension of the mechanisms underlying fluoroquinolones action.
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Affiliation(s)
- Liliana Brito
- Unidad de Patología Molecular del Neumococo, Centro Nacional de Microbiología, Instituto de Salud Carlos III Madrid, Spain
| | - Joana Wilton
- Unidad de Patología Molecular del Neumococo, Centro Nacional de Microbiología, Instituto de Salud Carlos III Madrid, Spain
| | - María J Ferrándiz
- Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos III Madrid, Spain
| | - Alicia Gómez-Sanz
- Unidad de Patología Molecular del Neumococo, Centro Nacional de Microbiología, Instituto de Salud Carlos III Madrid, Spain
| | - Adela G de la Campa
- Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos IIIMadrid, Spain; Presidencia, Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | - Mónica Amblar
- Unidad de Patología Molecular del Neumococo, Centro Nacional de Microbiología, Instituto de Salud Carlos III Madrid, Spain
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99
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Biological and Chemical Adaptation to Endogenous Hydrogen Peroxide Production in Streptococcus pneumoniae D39. mSphere 2017; 2:mSphere00291-16. [PMID: 28070562 PMCID: PMC5214746 DOI: 10.1128/msphere.00291-16] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 12/04/2016] [Indexed: 12/29/2022] Open
Abstract
Adaptation to endogenous oxidative stress is an integral aspect of Streptococcus pneumoniae colonization and virulence. In this work, we identify key transcriptomic and proteomic features of the pneumococcal endogenous oxidative stress response. The thiol peroxidase TpxD plays a critical role in adaptation to endogenous H2O2 and serves to limit protein sulfenylation of glycolytic, capsule, and nucleotide biosynthesis enzymes in S. pneumoniae. The catalase-negative, facultative anaerobe Streptococcus pneumoniae D39 is naturally resistant to hydrogen peroxide (H2O2) produced endogenously by pyruvate oxidase (SpxB). Here, we investigate the adaptive response to endogenously produced H2O2. We show that lactate oxidase, which converts lactate to pyruvate, positively impacts pyruvate flux through SpxB and that ΔlctO mutants produce significantly lower H2O2. In addition, both the SpxB pathway and a candidate pyruvate dehydrogenase complex (PDHC) pathway contribute to acetyl coenzyme A (acetyl-CoA) production during aerobic growth, and the pyruvate format lyase (PFL) pathway is the major acetyl-CoA pathway during anaerobic growth. Microarray analysis of the D39 strain cultured under aerobic versus strict anaerobic conditions shows upregulation of spxB, a gene encoding a rhodanese-like protein (locus tag spd0091), tpxD, sodA, piuB, piuD, and an Fe-S protein biogenesis operon under H2O2-producing conditions. Proteome profiling of H2O2-induced sulfenylation reveals that sulfenylation levels correlate with cellular H2O2 production, with endogenous sulfenylation of ≈50 proteins. Deletion of tpxD increases cellular sulfenylation 5-fold and has an inhibitory effect on ATP generation. Two major targets of protein sulfenylation are glyceraldehyde-3-phosphate dehydrogenase (GapA) and SpxB itself, but targets also include pyruvate kinase, LctO, AdhE, and acetate kinase (AckA). Sulfenylation of GapA is inhibitory, while the effect on SpxB activity is negligible. Strikingly, four enzymes of capsular polysaccharide biosynthesis are sulfenylated, as are enzymes associated with nucleotide biosynthesis via ribulose-5-phosphate. We propose that LctO/SpxB-generated H2O2 functions as a signaling molecule to downregulate capsule production and drive altered flux through sugar utilization pathways. IMPORTANCE Adaptation to endogenous oxidative stress is an integral aspect of Streptococcus pneumoniae colonization and virulence. In this work, we identify key transcriptomic and proteomic features of the pneumococcal endogenous oxidative stress response. The thiol peroxidase TpxD plays a critical role in adaptation to endogenous H2O2 and serves to limit protein sulfenylation of glycolytic, capsule, and nucleotide biosynthesis enzymes in S. pneumoniae.
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100
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Bryant JC, Dabbs RC, Oswalt KL, Brown LR, Rosch JW, Seo KS, Donaldson JR, McDaniel LS, Thornton JA. Pyruvate oxidase of Streptococcus pneumoniae contributes to pneumolysin release. BMC Microbiol 2016; 16:271. [PMID: 27829373 PMCID: PMC5103497 DOI: 10.1186/s12866-016-0881-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 10/28/2016] [Indexed: 11/21/2022] Open
Abstract
Background Streptococcus pneumoniae is one of the leading causes of community acquired pneumonia and acute otitis media. Certain aspects of S. pneumoniae’s virulence are dependent upon expression and release of the protein toxin pneumolysin (PLY) and upon the activity of the peroxide-producing enzyme, pyruvate oxidase (SpxB). We investigated the possible synergy of these two proteins and identified that release of PLY is enhanced by expression of SpxB prior to stationary phase growth. Results Mutants lacking the spxB gene were defective in PLY release and complementation of spxB restored PLY release. This was demonstrated by cytotoxic effects of sterile filtered supernatants upon epithelial cells and red blood cells. Additionally, peroxide production appeared to contribute to the mechanism of PLY release since a significant correlation was found between peroxide production and PLY release among a panel of clinical isolates. Exogenous addition of H2O2 failed to induce PLY release and catalase supplementation prevented PLY release in some strains, indicating peroxide may exert its effect intracellularly or in a strain-dependent manner. SpxB expression did not trigger bacterial cell death or LytA-dependent autolysis, but did predispose cells to deoxycholate lysis. Conclusions Here we demonstrate a novel link between spxB expression and PLY release. These findings link liberation of PLY toxin to oxygen availability and pneumococcal metabolism. Electronic supplementary material The online version of this article (doi:10.1186/s12866-016-0881-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Joseph C Bryant
- Department of Biological Sciences, Mississippi State University, 295 E Lee Blvd., Harned Hall, Rm 219, Mississippi State, MS, 39762, USA
| | - Ridge C Dabbs
- Department of Biological Sciences, Mississippi State University, 295 E Lee Blvd., Harned Hall, Rm 219, Mississippi State, MS, 39762, USA
| | - Katie L Oswalt
- Department of Biological Sciences, Mississippi State University, 295 E Lee Blvd., Harned Hall, Rm 219, Mississippi State, MS, 39762, USA
| | - Lindsey R Brown
- Department of Biological Sciences, Mississippi State University, 295 E Lee Blvd., Harned Hall, Rm 219, Mississippi State, MS, 39762, USA
| | - Jason W Rosch
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Keun S Seo
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, USA
| | - Janet R Donaldson
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, USA
| | - Larry S McDaniel
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Justin A Thornton
- Department of Biological Sciences, Mississippi State University, 295 E Lee Blvd., Harned Hall, Rm 219, Mississippi State, MS, 39762, USA.
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