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Murtha AN, Kazi M, Kim E, Rosch KM, Torres F, Dörr T. Multiple resistance factors collectively promote inoculum-dependent dynamic survival during antimicrobial peptide exposure in Enterobacter cloacae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.03.583169. [PMID: 38463991 PMCID: PMC10925329 DOI: 10.1101/2024.03.03.583169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Antimicrobial peptides (AMPs) are a promising tool with which to fight rising antibiotic resistance. However, pathogenic bacteria are equipped with several AMP defense mechanisms, whose contributions to AMP resistance are often poorly defined. Here, we evaluate the genetic determinants of resistance to an insect AMP, cecropin B, in the opportunistic pathogen Enterobacter cloacae. Single-cell analysis of E. cloacae's response to cecropin revealed marked heterogeneity in cell survival, phenotypically reminiscent of heteroresistance (the ability of a subpopulation to grow in the presence of supra-MIC concentration of antimicrobial). The magnitude of this response was highly dependent on initial E. cloacae inoculum. We identified 3 genetic factors which collectively contribute to E. cloacae resistance in response to the AMP cecropin: The PhoPQ-two-component system, OmpT-mediated proteolytic cleavage of cecropin, and Rcs-mediated membrane stress response. Altogether, this evidence suggests that multiple, independent mechanisms contribute to AMP resistance in E. cloacae.
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Affiliation(s)
- Andrew N. Murtha
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
- Department of Microbiology, Cornell University, Ithaca, NY 14853, USA
| | - Misha Kazi
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Eileen Kim
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Kelly M. Rosch
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Facundo Torres
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
- Department of Microbiology, Cornell University, Ithaca, NY 14853, USA
| | - Tobias Dörr
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
- Department of Microbiology, Cornell University, Ithaca, NY 14853, USA
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY 14853, USA
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2
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Sen O, Hinks J, Lin Q, Lin Q, Kjelleberg S, Rice SA, Seviour T. Escherichia coli displays a conserved membrane proteomic response to a range of alcohols. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:147. [PMID: 37789404 PMCID: PMC10546733 DOI: 10.1186/s13068-023-02401-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 09/18/2023] [Indexed: 10/05/2023]
Abstract
BACKGROUND Alcohol is a good and environment-friendly fuel that can be microbially produced, capable of eliminating many of the limitations of the present-day fossil fuels. However, the inherent toxic nature of alcohols to the microbial cells leads to end-product inhibition that limits large-scale alcohol production by fermentation. Fundamental knowledge about the stress responses of microorganisms to alcohols would greatly facilitate to improve the microbial alcohol tolerance. The current study elucidates and compares the changes in the membrane proteome of Escherichia coli in response to a range of alcohols. RESULTS Although alcohol toxicity increased exponentially with alcohol chain length (2-6 carbon), similar stress responses were observed in the inner and outer membrane proteome of E. coli in the presence of 2-, 4- and 6-carbon alcohols at the MIC50. This pertains to: (1) increased levels of inner membrane transporters for uptake of energy-producing metabolites, (2) reduced levels of non-essential proteins, associated with anaerobic, carbon starvation and osmotic stress, for energy conservation, (3) increased levels of murein degrading enzymes (MltA, EmtA, MliC and DigH) promoting cell elongation and 4) reduced levels of most outer membrane β-barrel proteins (LptD, FadL, LamB, TolC and BamA). Major outer membrane β-barrel protein OmpC, which is known to contribute to ethanol tolerance and membrane integrity, was notably reduced by alcohol stress. While LPS is important for OmpC trimerisation, LPS release by EDTA did not lower OmpC levels. This suggests that LPS release, which is reported under alcohol stress, does not contribute to the reduced levels of OmpC in the presence of alcohol. CONCLUSIONS Since alcohol primarily targets the integrity of the membrane, maintenance of outer membrane OmpC levels in the presence of alcohol might help in the survival of E. coli to higher alcohol concentrations. The study provides important information about the membrane protein responses of E. coli to a range of alcohols, which can be used to develop targeted strategies for increased microbial alcohol tolerance and hence bioalcohol production.
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Affiliation(s)
- Oishi Sen
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Jamie Hinks
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Qifeng Lin
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Qingsong Lin
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, 2052, Australia
| | - Scott A Rice
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- The Australian Institute for Microbiology and Immunology, University of Technology Sydney, Sydney, 2007, Australia
- CSIRO, Agriculture and Food, Westmead and Microbiomes for One Systems Health, Sydney, Australia
| | - Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.
- WATEC Aarhus University Centre for Water Technology, Universitetsbyen 36, Bldg 1783, 8000, Aarhus, Denmark.
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3
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Omptin Proteases of Enterobacterales Show Conserved Regulation by the PhoPQ Two-Component System but Exhibit Divergent Protection from Antimicrobial Host Peptides and Complement. Infect Immun 2023; 91:e0051822. [PMID: 36533918 PMCID: PMC9872669 DOI: 10.1128/iai.00518-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Bacteria that colonize eukaryotic surfaces interact with numerous antimicrobial host-produced molecules, including host defense peptides, complement, and antibodies. Bacteria have evolved numerous strategies to both detect and resist these molecules, and in the Enterobacterales order of bacteria these include alterations of the cell surface lipopolysaccharide structure and/or charge and the production of proteases that can degrade these antimicrobial molecules. Here, we show that omptin family proteases from Escherichia coli and Citrobacter rodentium are regulated by the PhoPQ system. Omptin protease activity is induced by growth in low Mg2+, and deletion of PhoP dramatically reduces omptin protease activity, transcriptional regulation, and protein levels. We identify conserved PhoP-binding sites in the promoters of the E. coli omptin genes ompT, ompP, and arlC as well as in croP of Citrobacter rodentium and show that mutation of the putative PhoP-binding site in the ompT promoter abrogates PhoP-dependent expression. Finally, we show that although regulation by PhoPQ is conserved, each of the omptin proteins has differential activity toward host defense peptides, complement components, and resistance to human serum, suggesting that each omptin confers unique survival advantages against specific host antimicrobial factors.
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4
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Molecular Insights into Substrate Binding of the Outer Membrane Enzyme OmpT. Catalysts 2023. [DOI: 10.3390/catal13020214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The enzyme OmpT of the outer membrane of Escherichia coli shows proteolytic activity and cleaves peptides and proteins. Using molecular dynamics simulations in a fully hydrated lipid bilayer on a time scale of hundreds of nanoseconds, we draw a detailed atomic picture of substrate recognition in the OmpT-holo enzyme complex. Hydrogen bonds and salt bridges are essential for maintaining the integrity of the active site and play a central role for OmpT in recognizing its substrate. Electrostatic interactions are critical at all stages from approaching the substrate to docking at the active site. Computational alanine scanning based on the Molecular Mechanics Generalized Born Surface Area (MM-GBSA) approach confirms the importance of multiple residues in the active site that form salt bridges. The substrate fluctuates along the axis of the β-barrel, which is associated with oscillations of the binding cleft formed by the residue pairs D210-H212 and D83-D85. Principal component analysis suggests that substrate and protein movements are correlated. We observe the transient presence of putative catalytic water molecules near the active site, which may be involved in the nucleophilic attack on the cleavable peptide bond of the substrate.
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5
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Alkhaldi NK, Alghamdi WK, Alharbi MH, Almutairi AS, Alghamdi FT. The Association Between Oral Helicobacter pylori and Gastric Complications: A Comprehensive Review. Cureus 2022; 14:e24703. [PMID: 35663643 PMCID: PMC9162906 DOI: 10.7759/cureus.24703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/26/2022] [Indexed: 12/13/2022] Open
Abstract
Helicobacter pylori (H. pylori) is linked to chronic gastritis, duodenal or gastric ulcers, and gastric cancer (GC). Because the oral cavity is the first component of the gastrointestinal tract (GIT) and the entrance point for H. pylori, it has been proposed as a possible reservoir of H. pylori. As a result, a putative oral-oral transmission pathway of H. pylori poses the possibility of whether personal contact, such as kissing or sharing a meal, might trigger H. pylori transmission. As a result, several investigations have been done on this issue using various approaches for detecting H. pylori in oral and stomach samples. Furthermore, the relationship between H. pylori and gastrointestinal disorders has yet to be studied. The evidence for the association between H. pylori and gastric diseases and their complications is still a controversial subject due to the existing literature in this review. The goal of this comprehensive review was to collect all available published articles and critically evaluate existing investigations looking into the relationship between oral H. pylori contamination and the danger of gastric complications. Few studies indicated an association between H. pylori and gastric diseases. Furthermore, more longitudinal randomized clinical studies to further investigate the association between H. pylori and gastric diseases are warranted.
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Affiliation(s)
- Njoud K Alkhaldi
- General Medicine and Surgery, College of Medicine, Princess Nourah bint Abdulrahman University, Riyadh, SAU
| | - Waad K Alghamdi
- General Medicine and Surgery, College of Medicine, Princess Nourah bint Abdulrahman University, Riyadh, SAU
| | - Maryam H Alharbi
- General Medicine and Surgery, College of Medicine, Princess Nourah bint Abdulrahman University, Riyadh, SAU
| | - Albandri S Almutairi
- General Medicine and Surgery, College of Medicine, Princess Nourah bint Abdulrahman University, Riyadh, SAU
| | - Faisal T Alghamdi
- Department of Oral Biology, Faculty of Dentistry, King Abdulaziz University, Jeddah, SAU
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6
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Kum SL, Ho JCS, Parikh AN, Liedberg B. Amphiphilic Membrane Environments Regulate Enzymatic Behaviors of Salmonella Outer Membrane Protease. ACS BIO & MED CHEM AU 2022; 2:73-83. [PMID: 37102179 PMCID: PMC10114716 DOI: 10.1021/acsbiomedchemau.1c00027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
The role of an amphiphilic environment in the functional regulation of integral membrane proteins is well appreciated but how specific amphiphilic surrounding influences the conformational plasticity and function of a protein is less obvious. We focus on the Salmonella phosphoglycerate transport system (pgt)-encoded outer membrane protease E (PgtE), which plays an important role in tissue infiltration and survival of Salmonella enterica. Despite our understanding of its physiological functions, elucidation of its enzymatic behavior in response to the immediate amphiphilic surrounding is lacking. We monitor the proteolytic activity of PgtE reconstituted in Zwittergent 3-12 detergent micelles or a 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) bilayer and examine factors that influence its activity. We find, to our surprise, that PgtE, which is thought to elicit a rapid response toward various substrates, showed hysteretic enzymatic behavior, characterized by a prominent lag phase prior to achieving the exponential steady state in its detergent-stabilized form as well as in the outer membrane embedded native state in live bacteria. The lag phase was abolished under three conditions: preformation of an inactive detergent-stabilized PgtE-substrate complex without lipopolysaccharide (LPS), LPS-bound detergent-stabilized PgtE that had reached steady state velocity, or PgtE reconstituted into a POPC bilayer environment. Interestingly, detergent- and bilayer-stabilized PgtE showed comparable steady-state activity. And strikingly, lipopolysaccharide (LPS) becomes nonessential for the activation of PgtE when the protein is reconstituted in the phospholipid bilayer, contrasting a long-standing notion that LPS is required for proteases belonging to the omptin family to be proteolytically active. These findings suggest intriguing biological nuances for the proteolytic function of PgtE that were not well appreciated previously and offer new perspectives that may generally be applicable for omptins.
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Affiliation(s)
- Siau Ling Kum
- Centre
for Biomimetic Sensor Science, Nanyang Technological
University, 50 Nanyang Drive, 637553 Singapore
- School
of Materials Science and Engineering, Nanyang
Technological University, 50 Nanyang Ave, 639798 Singapore
| | - James C. S. Ho
- Centre
for Biomimetic Sensor Science, Nanyang Technological
University, 50 Nanyang Drive, 637553 Singapore
- School
of Materials Science and Engineering, Nanyang
Technological University, 50 Nanyang Ave, 639798 Singapore
| | - Atul N. Parikh
- Centre
for Biomimetic Sensor Science, Nanyang Technological
University, 50 Nanyang Drive, 637553 Singapore
- School
of Materials Science and Engineering, Nanyang
Technological University, 50 Nanyang Ave, 639798 Singapore
- Department of Chemistry and Department of
Biomedical Engineering, University of California, Davis, California 95616, United States
| | - Bo Liedberg
- Centre
for Biomimetic Sensor Science, Nanyang Technological
University, 50 Nanyang Drive, 637553 Singapore
- School
of Materials Science and Engineering, Nanyang
Technological University, 50 Nanyang Ave, 639798 Singapore
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7
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Hermansen S, Linke D, Leo JC. Transmembrane β-barrel proteins of bacteria: From structure to function. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2022; 128:113-161. [PMID: 35034717 DOI: 10.1016/bs.apcsb.2021.07.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The outer membrane of Gram-negative bacteria is a specialized organelle conferring protection to the cell against various environmental stresses and resistance to many harmful compounds. The outer membrane has a number of unique features, including an asymmetric lipid bilayer, the presence of lipopolysaccharides and an individual proteome. The vast majority of the integral transmembrane proteins in the outer membrane belongs to the family of β-barrel proteins. These evolutionarily related proteins share a cylindrical, anti-parallel β-sheet core fold spanning the outer membrane. The loops and accessory domains attached to the β-barrel allow for a remarkable versatility in function for these proteins, ranging from diffusion pores and transporters to enzymes and adhesins. We summarize the current knowledge on β-barrel structure and folding and give an overview of their functions, evolution, and potential as drug targets.
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Affiliation(s)
- Simen Hermansen
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Dirk Linke
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Jack C Leo
- Antimicrobial resistance, Omics and Microbiota Group, Department of Biosciences, Nottingham Trent University, Nottingham, United Kingdom.
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8
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Schafer ME, Browne H, Goldberg JB, Greenberg DE. Peptides and Antibiotic Therapy: Advances in Design and Delivery. Acc Chem Res 2021; 54:2377-2385. [PMID: 33881843 DOI: 10.1021/acs.accounts.1c00040] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Antibiotic resistance (AMR) is an increasing public health crisis worldwide. This threatens our ability to adequately care for patients with infections due to multi-drug-resistant (MDR) pathogens. As such, there is an urgent need to develop new classes of antimicrobials that are not based on currently utilized antibiotic scaffolds. One promising avenue of antimicrobial research that deserves renewed examination involves the use of peptides. Although antimicrobial peptides (AMPs) have been studied for a number of years, innovations in peptide design and their applications are increasingly making this approach a viable alternative to traditional small-molecule antibiotics. This review will provide updates on two ways in which peptides are being explored as antibiotics. The first topic will focus on novel types of peptides and conjugation methods that are being exploited to act as antibiotics themselves. These direct-acting modified peptides could serve as potentially useful drugs while mitigating many of the known liabilities of AMPs. The second topic relates to the use of peptides as delivery vehicles for other active compounds with antimicrobial activity. Cell-penetrating peptides (CPPs) are peptides designed to carry compounds across cell membranes and are a promising method for delivering a variety of antimicrobial compounds. When conjugated to other compounds, CPPs have been shown to be effective at increasing the uptake of both small- and large-molecular-weight compounds. This includes conjugation to antisense molecules and traditional antibiotics, resulting in increased effectiveness of these antimicrobials. One particular approach utilizes CPPs conjugated to phosphorodiamidate morpholino oligomers (PMOs). PMOs are designed to target particular pathogens in a gene-specific way. They target mRNA and block protein translation. Peptide-conjugated PMOs (PPMOs) allow for efficient delivery into the Gram-negative cytoplasm, and recent updates to their in vitro and in vivo activity are reviewed. This includes recent data to suggest that PPMOs maintain activity in the setting of multi-drug-resistant (MDR) strains, an important finding as it relates to the further development of this therapeutic approach. Other topics include the ability to have activity in the biofilm setting, a finding that likely relates to the peptide portion of the conjugate. Finally, what is known and anticipated related to the development of resistance to these peptides will be discussed.
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Affiliation(s)
- Morgan E. Schafer
- Division of Pulmonary, Allergy and Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics and Center for Cystic Fibrosis and Airway Diseases Research, Children’s Healthcare of Atlanta, Emory University School of Medicine, 1510 Clifton Road NE, Suite 3009, Atlanta, Georgia 30322, United States
| | | | - Joanna B. Goldberg
- Division of Pulmonary, Allergy and Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics and Center for Cystic Fibrosis and Airway Diseases Research, Children’s Healthcare of Atlanta, Emory University School of Medicine, 1510 Clifton Road NE, Suite 3009, Atlanta, Georgia 30322, United States
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9
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Nguyen SV, Muthappa DM, Eshwar AK, Buckley JF, Murphy BP, Stephan R, Lehner A, Fanning S. Comparative genomic insights into Yersinia hibernica - a commonly misidentified Yersinia enterocolitica-like organism. Microb Genom 2020; 6:mgen000411. [PMID: 32701425 PMCID: PMC7643974 DOI: 10.1099/mgen.0.000411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 07/07/2020] [Indexed: 11/18/2022] Open
Abstract
Food-associated outbreaks linked to enteropathogenic Yersinia enterocolitica are of concern to public health. Pigs and their meat are recognized risk factors for transmission of Y. enterocolitica. This study aimed to describe the comparative genomics of Y. enterocolitica along with a number of misclassified Yersinia isolates, now constituting the recently described Yersinia hibernica. The latter was originally cultured from an environmental sample taken at a pig slaughterhouse. Unique features were identified in the genome of Y. hibernica, including a novel integrative conjugative element (ICE), denoted as ICEYh-1 contained within a 255 kbp region of plasticity. In addition, a zebrafish embryo infection model was adapted and applied to assess the virulence potential among Yersinia isolates including Y. hibernica.
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Affiliation(s)
- Scott Van Nguyen
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, Belfield, Dublin D04 N2E5, Ireland
| | - Dechamma Mundanda Muthappa
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, Belfield, Dublin D04 N2E5, Ireland
| | - Athmanya K. Eshwar
- Institute for Food Safety and Hygiene, University of Zurich, Zurich, Switzerland
| | - James F. Buckley
- Veterinary Food Safety Laboratory, Cork County Council, Inniscarra, Co. Cork and Department of Microbiology, National University of Ireland, Cork, College Road, Cork, Ireland
| | - Brenda P. Murphy
- Veterinary Food Safety Laboratory, Cork County Council, Inniscarra, Co. Cork and Department of Microbiology, National University of Ireland, Cork, College Road, Cork, Ireland
| | - Roger Stephan
- Institute for Food Safety and Hygiene, University of Zurich, Zurich, Switzerland
| | - Angelika Lehner
- Institute for Food Safety and Hygiene, University of Zurich, Zurich, Switzerland
| | - Séamus Fanning
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, Belfield, Dublin D04 N2E5, Ireland
- Institute for Global Food Security, Queen’s University Belfast, 19 Chlorine Gardens, Belfast BT9 5AG, UK
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10
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Banerjee SK, Crane SD, Pechous RD. A Dual Role for the Plasminogen Activator Protease During the Preinflammatory Phase of Primary Pneumonic Plague. J Infect Dis 2020; 222:407-416. [PMID: 32128567 PMCID: PMC7336565 DOI: 10.1093/infdis/jiaa094] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/27/2020] [Indexed: 12/12/2022] Open
Abstract
Early after inhalation, Yersinia pestis replicates to high numbers in the airways in the absence of disease symptoms or notable inflammatory responses to cause primary pneumonic plague. The plasminogen activator protease (Pla) is a critical Y. pestis virulence factor that is important for early bacterial growth in the lung via an unknown mechanism. In this article, we define a dual role for Pla in the initial stages of pulmonary infection. We show that Pla functions as an adhesin independent of its proteolytic function to suppress early neutrophil influx into the lungs, and that Pla enzymatic activity contributes to bacterial resistance to neutrophil-mediated bacterial killing. Our results suggest that the fate of Y. pestis infection of the lung is decided extremely early during infection and that Pla plays a dual role to tilt the balance in favor of the pathogen.
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Affiliation(s)
- Srijon K Banerjee
- University of Arkansas for Medical Sciences, Department of Microbiology and Immunology, Little Rock, Arkansas, USA
| | - Samantha D Crane
- University of Arkansas for Medical Sciences, Department of Microbiology and Immunology, Little Rock, Arkansas, USA
| | - Roger D Pechous
- University of Arkansas for Medical Sciences, Department of Microbiology and Immunology, Little Rock, Arkansas, USA,Correspondence: Roger D. Pechous, Department of Microbiology and Immunology, 4301 W. Markham St., Slot 511, Little Rock, AR 72205 ()
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11
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Baindara P, Ghosh AK, Mandal SM. Coevolution of Resistance Against Antimicrobial Peptides. Microb Drug Resist 2020; 26:880-899. [PMID: 32119634 DOI: 10.1089/mdr.2019.0291] [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: 11/12/2022] Open
Abstract
Antimicrobial peptides (AMPs) are produced by all forms of life, ranging from eukaryotes to prokaryotes, and they are a crucial component of innate immunity, involved in clearing infection by inhibiting pathogen colonization. In the recent past, AMPs received high attention due to the increase of extensive antibiotic resistance by these pathogens. AMPs exhibit a diverse spectrum of activity against bacteria, fungi, parasites, and various types of cancer. AMPs are active against various bacterial pathogens that cause disease in animals and plants. However, because of the coevolution of host and pathogen interaction, bacteria have developed the mechanisms to sense and exhibit an adaptive response against AMPs. These resistance mechanisms are playing an important role in bacterial virulence within the host. Here, we have discussed the different resistance mechanisms used by gram-positive and gram-negative bacteria to sense and combat AMP actions. Understanding the mechanism of AMP resistance may provide directions toward the development of novel therapeutic strategies to control multidrug-resistant pathogens.
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Affiliation(s)
- Piyush Baindara
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Ananta K Ghosh
- Department of Biotechnology, Central Research Facility, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Santi M Mandal
- Department of Biotechnology, Central Research Facility, Indian Institute of Technology Kharagpur, Kharagpur, India
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12
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Jang H, Gopinath GR, Eshwar A, Srikumar S, Nguyen S, Gangiredla J, Patel IR, Finkelstein SB, Negrete F, Woo J, Lee Y, Fanning S, Stephan R, Tall BD, Lehner A. The Secretion of Toxins and Other Exoproteins of Cronobacter: Role in Virulence, Adaption, and Persistence. Microorganisms 2020; 8:E229. [PMID: 32046365 PMCID: PMC7074816 DOI: 10.3390/microorganisms8020229] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/28/2020] [Accepted: 02/06/2020] [Indexed: 12/29/2022] Open
Abstract
: Cronobacter species are considered an opportunistic group of foodborne pathogenic bacteria capable of causing both intestinal and systemic human disease. This review describes common virulence themes shared among the seven Cronobacter species and describes multiple exoproteins secreted by Cronobacter, many of which are bacterial toxins that may play a role in human disease. The review will particularly concentrate on the virulence factors secreted by C. sakazakii, C. malonaticus, and C. turicensis, which are the primary human pathogens of interest. It has been discovered that various species-specific virulence factors adversely affect a wide range of eukaryotic cell processes including protein synthesis, cell division, and ion secretion. Many of these factors are toxins which have been shown to also modulate the host immune response. These factors are encoded on a variety of mobile genetic elements such as plasmids and transposons; this genomic plasticity implies ongoing re-assortment of virulence factor genes which has complicated our efforts to categorize Cronobacter into sharply defined genomic pathotypes.
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Affiliation(s)
- Hyein Jang
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - Gopal R. Gopinath
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - Athmanya Eshwar
- Institute for Food Safety and Hygiene, University of Zurich, Zurich CH-8006 Zürich, Switzerland; (A.E.); (R.S.); (A.L.)
| | - Shabarinath Srikumar
- UCD-Centre for Food Safety, Science Centre South, University College Dublin, Dublin Belfield, Dublin 4, D04 V1W8, Ireland; (S.S.); (S.N.); (S.F.)
| | - Scott Nguyen
- UCD-Centre for Food Safety, Science Centre South, University College Dublin, Dublin Belfield, Dublin 4, D04 V1W8, Ireland; (S.S.); (S.N.); (S.F.)
| | - Jayanthi Gangiredla
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - Isha R. Patel
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - Samantha B. Finkelstein
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - Flavia Negrete
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - JungHa Woo
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - YouYoung Lee
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - Séamus Fanning
- UCD-Centre for Food Safety, Science Centre South, University College Dublin, Dublin Belfield, Dublin 4, D04 V1W8, Ireland; (S.S.); (S.N.); (S.F.)
| | - Roger Stephan
- Institute for Food Safety and Hygiene, University of Zurich, Zurich CH-8006 Zürich, Switzerland; (A.E.); (R.S.); (A.L.)
| | - Ben D. Tall
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - Angelika Lehner
- Institute for Food Safety and Hygiene, University of Zurich, Zurich CH-8006 Zürich, Switzerland; (A.E.); (R.S.); (A.L.)
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13
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Vaca DJ, Thibau A, Schütz M, Kraiczy P, Happonen L, Malmström J, Kempf VAJ. Interaction with the host: the role of fibronectin and extracellular matrix proteins in the adhesion of Gram-negative bacteria. Med Microbiol Immunol 2019; 209:277-299. [PMID: 31784893 PMCID: PMC7248048 DOI: 10.1007/s00430-019-00644-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 11/14/2019] [Indexed: 01/03/2023]
Abstract
The capacity of pathogenic microorganisms to adhere to host cells and avoid clearance by the host immune system is the initial and most decisive step leading to infections. Bacteria have developed different strategies to attach to diverse host surface structures. One important strategy is the adhesion to extracellular matrix (ECM) proteins (e.g., collagen, fibronectin, laminin) that are highly abundant in connective tissue and basement membranes. Gram-negative bacteria express variable outer membrane proteins (adhesins) to attach to the host and to initiate the process of infection. Understanding the underlying molecular mechanisms of bacterial adhesion is a prerequisite for targeting this interaction by “anti-ligands” to prevent colonization or infection of the host. Future development of such “anti-ligands” (specifically interfering with bacteria-host matrix interactions) might result in the development of a new class of anti-infective drugs for the therapy of infections caused by multidrug-resistant Gram-negative bacteria. This review summarizes our current knowledge about the manifold interactions of adhesins expressed by Gram-negative bacteria with ECM proteins and the use of this information for the generation of novel therapeutic antivirulence strategies.
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Affiliation(s)
- Diana J Vaca
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University Frankfurt am Main, Paul-Ehrlich-Str. 40, 60596, Frankfurt, Germany
| | - Arno Thibau
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University Frankfurt am Main, Paul-Ehrlich-Str. 40, 60596, Frankfurt, Germany
| | - Monika Schütz
- Institute for Medical Microbiology and Infection Control, University Hospital, Eberhard Karls-University, Tübingen, Germany
| | - Peter Kraiczy
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University Frankfurt am Main, Paul-Ehrlich-Str. 40, 60596, Frankfurt, Germany
| | - Lotta Happonen
- Division of Infection Medicine, Department of Clinical Sciences, Faculty of Medicine, Lund University, Lund, Sweden
| | - Johan Malmström
- Division of Infection Medicine, Department of Clinical Sciences, Faculty of Medicine, Lund University, Lund, Sweden
| | - Volkhard A J Kempf
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University Frankfurt am Main, Paul-Ehrlich-Str. 40, 60596, Frankfurt, Germany.
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14
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Abdi M, Mirkalantari S, Amirmozafari N. Bacterial resistance to antimicrobial peptides. J Pept Sci 2019; 25:e3210. [DOI: 10.1002/psc.3210] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/04/2019] [Accepted: 07/21/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Milad Abdi
- Student Research Committee, Faculty of MedicineIran University of Medical Sciences Tehran Iran
- Department of Microbiology, Faculty of MedicineIran University of Medical Sciences Tehran Iran
| | - Shiva Mirkalantari
- Department of Microbiology, Faculty of MedicineIran University of Medical Sciences Tehran Iran
| | - Nour Amirmozafari
- Department of Microbiology, Faculty of MedicineIran University of Medical Sciences Tehran Iran
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15
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Desloges I, Taylor JA, Leclerc JM, Brannon JR, Portt A, Spencer JD, Dewar K, Marczynski GT, Manges A, Gruenheid S, Le Moual H, Thomassin JL. Identification and characterization of OmpT-like proteases in uropathogenic Escherichia coli clinical isolates. Microbiologyopen 2019; 8:e915. [PMID: 31496120 PMCID: PMC6854850 DOI: 10.1002/mbo3.915] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/01/2019] [Accepted: 07/06/2019] [Indexed: 01/01/2023] Open
Abstract
Bacterial colonization of the urogenital tract is limited by innate defenses, including the production of antimicrobial peptides (AMPs). Uropathogenic Escherichia coli (UPEC) resist AMP‐killing to cause a range of urinary tract infections (UTIs) including asymptomatic bacteriuria, cystitis, pyelonephritis, and sepsis. UPEC strains have high genomic diversity and encode numerous virulence factors that differentiate them from non‐UTI‐causing strains, including ompT. As OmpT homologs cleave and inactivate AMPs, we hypothesized that UPEC strains from patients with symptomatic UTIs have high OmpT protease activity. Therefore, we measured OmpT activity in 58 clinical E. coli isolates. While heterogeneous OmpT activities were observed, OmpT activity was significantly greater in UPEC strains isolated from patients with symptomatic infections. Unexpectedly, UPEC strains exhibiting the greatest protease activities harbored an additional ompT‐like gene called arlC (ompTp). The presence of two OmpT‐like proteases in some UPEC isolates led us to compare the substrate specificities of OmpT‐like proteases found in E. coli. While all three cleaved AMPs, cleavage efficiency varied on the basis of AMP size and secondary structure. Our findings suggest the presence of ArlC and OmpT in the same UPEC isolate may confer a fitness advantage by expanding the range of target substrates.
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Affiliation(s)
- Isabelle Desloges
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - James A Taylor
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Jean-Mathieu Leclerc
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - John R Brannon
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Andrea Portt
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - John D Spencer
- Division of Nephrology, Nationwide Children's Hospital, Columbus, Ohio
| | - Ken Dewar
- Microbiome and Disease Tolerance Centre, McGill University, Montreal, QC, Canada.,Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Gregory T Marczynski
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada.,Microbiome and Disease Tolerance Centre, McGill University, Montreal, QC, Canada
| | - Amee Manges
- School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada
| | - Samantha Gruenheid
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada.,Microbiome and Disease Tolerance Centre, McGill University, Montreal, QC, Canada
| | - Hervé Le Moual
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada.,Microbiome and Disease Tolerance Centre, McGill University, Montreal, QC, Canada.,Faculty of Dentistry, McGill University, Montreal, QC, Canada
| | - Jenny-Lee Thomassin
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
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16
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"NETtling" the host: Breaking of tolerance in chronic inflammation and chronic infection. J Autoimmun 2019; 88:1-10. [PMID: 29100671 DOI: 10.1016/j.jaut.2017.10.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/24/2017] [Accepted: 10/24/2017] [Indexed: 12/31/2022]
Abstract
How and why we break tolerance to self-proteins still remains a largely unanswered question. Neutrophils have been identified as a rich source of autoantigens in a wide array of autoimmune diseases that arise as a consequence of different environmental and genetic factors, e.g. rheumatoid arthritis (RA), lupus, vasculitis, cystic fibrosis (CF) etc. Specifically, neutrophil extracellular trap (NET) formation has been identified as a link between innate and adaptive immune responses in autoimmunity. Autoantigens including neutrophil granular proteins (targeted by anti-neutrophil cytoplasmic antibodies, ANCA) as well as post-translationally modified proteins, i.e. citrullinated and carbamylated proteins targeted by anti-citrullinated protein antibodies (ACPA) and anti-carbamylated protein antibodies (ACarPA), respectively, localize to the NETs. Moreover, NETs provide stimuli to dendritic cells that potentiate adaptive autoimmune responses. However, while NETs promote inflammation and appear to induce humoral autoreactivity across autoimmune diseases, the antigen specificity of autoantibodies found in these disorders is striking. These unique autoantigen signatures suggest that not all NETs are created equal and that the environment in which NETs arise shapes their disease-specific character. In this review article, we discuss the effects of different stimuli on the mechanism of NET formation as well as how they contribute to antigen specificity in the breaking of immune tolerance. Specifically, we compare and contrast the autoreactive nature of NETs in two settings of chronic airway inflammation: one triggered by smoking, a recognized environmental NET stimulus in RA patients, and one mediated by Pseudomonas aeruginosa, the most prevalent lung pathogen in CF patients. Finally, we draw attention to novel findings that, together with the specific environmental/chemical stimuli, should be taken into account when investigating how and why antigen specificity arises in the context of NET formation.
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17
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Zhao Y, Gao X, Guo J, Yu D, Xiao Y, Wang H, Li Y. Helicobacter pylori infection alters gastric and tongue coating microbial communities. Helicobacter 2019; 24:e12567. [PMID: 30734438 PMCID: PMC6593728 DOI: 10.1111/hel.12567] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/25/2018] [Accepted: 12/26/2018] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Infection with Helicobacter pylori (H pylori), especially cytotoxin-associated gene A-positive (CagA+) strains, has been associated with various gastrointestinal and extragastric diseases. The aim of this study was to characterize H pylori-induced alterations in the gastric and tongue coating microbiota and evaluate their potential impacts on human health. DESIGN The gastric mucosa and tongue coating specimens were collected from 80 patients with chronic gastritis, and microbiota profiles were generated by 16S rRNA gene sequencing. Samples were grouped as H pylori negative (n = 32), CagA-negative H pylori infection (n = 13), and CagA-positive H pylori infection (n=35). The comparison of bacterial relative abundance was made using a generalized linear model. Functional profiling of microbial communities was predicted with PICRUSt and BugBase. Microbial correlation networks were produced by utilizing SparCC method. RESULTS Significant alterations of the gastric microbiota were found in the H pylori+/CagA+ samples, represented by a decrease in bacterial diversity, a reduced abundance of Roseburia, and increased abundances of Helicobacter and Haemophilus genera. At the community level, functions involved in biofilm forming, mobile element content, and facultative anaerobiosis were significantly decreased in gastric microbiome of the H pylori+ subjects. The presence of CagA gene was linked to an increased proportion of Gram-negative bacteria in the stomach, thereby contributing to an upregulation of lipopolysaccharide (LPS) biosynthesis. The number of bacterial interactions was greatly reduced in networks of both tongue coating and gastric microbiota of the H pylori+/CagA+ subject, and the cooperative bacterial interactions dominated the tongue coating microbiome. CONCLUSIONS Infection with H pylori strains possessing CagA may increase the risk of various diseases, by upregulating LPS biosynthesis in the stomach and weakening the defense of oral microbiota against microorganisms with pathogenic potential.
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Affiliation(s)
- Yubin Zhao
- The Traditional Chinese Medicine Hospital of Shijiazhuang Affiliated to Hebei University of Chinese MedicineShijiazhuangChina
| | - Xuefeng Gao
- Shenzhen University General HospitalShenzhenChina,Shenzhen University Clinical Medical AcademyShenzhenChina
| | - Jiaxuan Guo
- The Traditional Chinese Medicine Hospital of Shijiazhuang Affiliated to Hebei University of Chinese MedicineShijiazhuangChina
| | - Dongbao Yu
- Shenzhen Hoiracle Bio‐Tech Co., Ltd.ShenzhenChina
| | - Ying Xiao
- Department of Bioengineering, School of Chemical EngineeringShijiazhuang UniversityShijiazhuangChina
| | - Huijie Wang
- The Traditional Chinese Medicine Hospital of Shijiazhuang Affiliated to Hebei University of Chinese MedicineShijiazhuangChina
| | - Yuchan Li
- The Traditional Chinese Medicine Hospital of Shijiazhuang Affiliated to Hebei University of Chinese MedicineShijiazhuangChina
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18
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Spread and Persistence of Virulence and Antibiotic Resistance Genes: A Ride on the F Plasmid Conjugation Module. EcoSal Plus 2019; 8. [PMID: 30022749 DOI: 10.1128/ecosalplus.esp-0003-2018] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The F plasmid or F-factor is a large, 100-kbp, circular conjugative plasmid of Escherichia coli and was originally described as a vector for horizontal gene transfer and gene recombination in the late 1940s. Since then, F and related F-like plasmids have served as role models for bacterial conjugation. At present, more than 200 different F-like plasmids with highly related DNA transfer genes, including those for the assembly of a type IV secretion apparatus, are completely sequenced. They belong to the phylogenetically related MOBF12A group. F-like plasmids are present in enterobacterial hosts isolated from clinical as well as environmental samples all over the world. As conjugative plasmids, F-like plasmids carry genetic modules enabling plasmid replication, stable maintenance, and DNA transfer. In this plasmid backbone of approximately 60 kbp, the DNA transfer genes occupy the largest and mostly conserved part. Subgroups of MOBF12A plasmids can be defined based on the similarity of TraJ, a protein required for DNA transfer gene expression. In addition, F-like plasmids harbor accessory cargo genes, frequently embedded within transposons and/or integrons, which harness their host bacteria with antibiotic resistance and virulence genes, causing increasingly severe problems for the treatment of infectious diseases. Here, I focus on key genetic elements and their encoded proteins present on the F-factor and other typical F-like plasmids belonging to the MOBF12A group of conjugative plasmids.
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19
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Contribution of the Cpx envelope stress system to metabolism and virulence regulation in Salmonella enterica serovar Typhimurium. PLoS One 2019; 14:e0211584. [PMID: 30716090 PMCID: PMC6361445 DOI: 10.1371/journal.pone.0211584] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 01/16/2019] [Indexed: 11/19/2022] Open
Abstract
The Cpx-envelope stress system regulates the expression of virulence factors in many Gram-negative pathogens. In Salmonella enterica serovar Typhimurium deletion of the sensor kinase CpxA but not of the response regulator CpxR results in the down regulation of the key regulator for invasion, HilA encoded by the Salmonella pathogenicity island 1 (SPI-1). Here, we provide evidence that cpxA deletion interferes with dephosphorylation of CpxR resulting in increased levels of active CpxR and consequently in misregulation of target genes. 14 potential operons were identified to be under direct control of CpxR. These include the virulence determinants ecotin, the omptin PgtE, and the SPI-2 regulator SsrB. The Tat-system and the PocR regulator that together promote anaerobic respiration of tetrathionate on 1,2-propanediol are also under direct CpxR control. Notably, 1,2-propanediol represses hilA expression. Thus, our work demonstrates for the first time the involvement of the Cpx system in a complex network mediating metabolism and virulence function.
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20
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Wrobel A, Ottoni C, Leo JC, Linke D. pYR4 From a Norwegian Isolate of Yersinia ruckeri Is a Putative Virulence Plasmid Encoding Both a Type IV Pilus and a Type IV Secretion System. Front Cell Infect Microbiol 2018; 8:373. [PMID: 30460204 PMCID: PMC6232867 DOI: 10.3389/fcimb.2018.00373] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 10/04/2018] [Indexed: 01/14/2023] Open
Abstract
Enteric redmouth disease caused by the pathogen Yersinia ruckeri is a significant problem for fish farming around the world. Despite its importance, only a few virulence factors of Y. ruckeri have been identified and studied in detail. Here, we report and analyze the complete DNA sequence of pYR4, a plasmid from a highly pathogenic Norwegian Y. ruckeri isolate, sequenced using PacBio SMRT technology. Like the well-known pYV plasmid of human pathogenic Yersiniae, pYR4 is a member of the IncFII family. Thirty-one percent of the pYR4 sequence is unique compared to other Y. ruckeri plasmids. The unique regions contain, among others genes, a large number of mobile genetic elements and two partitioning systems. The G+C content of pYR4 is higher than that of the Y. ruckeri NVH_3758 genome, indicating its relatively recent horizontal acquisition. pYR4, as well as the related plasmid pYR3, comprises operons that encode for type IV pili and for a conjugation system (tra). In contrast to other Yersinia plasmids, pYR4 cannot be cured at elevated temperatures. Our study highlights the power of PacBio sequencing technology for identifying mis-assembled segments of genomic sequences. Comparative analysis of pYR4 and other Y. ruckeri plasmids and genomes, which were sequenced by second and the third generation sequencing technologies, showed errors in second generation sequencing assemblies. Specifically, in the Y. ruckeri 150 and Y. ruckeri ATCC29473 genome assemblies, we mapped the entire pYR3 plasmid sequence. Placing plasmid sequences on the chromosome can result in erroneous biological conclusions. Thus, PacBio sequencing or similar long-read methods should always be preferred for de novo genome sequencing. As the tra operons of pYR3, although misplaced on the chromosome during the genome assembly process, were demonstrated to have an effect on virulence, and type IV pili are virulence factors in many bacteria, we suggest that pYR4 directly contributes to Y. ruckeri virulence.
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Affiliation(s)
| | - Claudio Ottoni
- Centre for Ecological and Evolutionary Synthesis, University of Oslo, Oslo, Norway
| | - Jack C Leo
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Dirk Linke
- Department of Biosciences, University of Oslo, Oslo, Norway
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21
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Role of a single noncoding nucleotide in the evolution of an epidemic African clade of Salmonella. Proc Natl Acad Sci U S A 2018; 115:E2614-E2623. [PMID: 29487214 PMCID: PMC5856525 DOI: 10.1073/pnas.1714718115] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Invasive nontyphoidal Salmonella disease is a major and previously neglected tropical disease responsible for an estimated ∼390,000 deaths per year in Africa, largely caused by a variant of Salmonella Typhimurium called ST313. Despite the availability of >100,000 Salmonella genomes, it has proven challenging to associate individual SNPs with pathogenic traits of this dangerous bacterium. Here, we used a transcriptomic strategy to identify a single-nucleotide change in a promoter region responsible for crucial phenotypic differences of African S. Typhimurium. Our findings show that a noncoding nucleotide of the bacterial genome can have a profound effect upon the pathogenesis of infectious disease. Salmonella enterica serovar Typhimurium ST313 is a relatively newly emerged sequence type that is causing a devastating epidemic of bloodstream infections across sub-Saharan Africa. Analysis of hundreds of Salmonella genomes has revealed that ST313 is closely related to the ST19 group of S. Typhimurium that cause gastroenteritis across the world. The core genomes of ST313 and ST19 vary by only ∼1,000 SNPs. We hypothesized that the phenotypic differences that distinguish African Salmonella from ST19 are caused by certain SNPs that directly modulate the transcription of virulence genes. Here we identified 3,597 transcriptional start sites of the ST313 strain D23580, and searched for a gene-expression signature linked to pathogenesis of Salmonella. We identified a SNP in the promoter of the pgtE gene that caused high expression of the PgtE virulence factor in African S. Typhimurium, increased the degradation of the factor B component of human complement, contributed to serum resistance, and modulated virulence in the chicken infection model. We propose that high levels of PgtE expression by African S. Typhimurium ST313 promote bacterial survival and dissemination during human infection. Our finding of a functional role for an extragenic SNP shows that approaches used to deduce the evolution of virulence in bacterial pathogens should include a focus on noncoding regions of the genome.
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22
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Delabranche X, Helms J, Meziani F. Immunohaemostasis: a new view on haemostasis during sepsis. Ann Intensive Care 2017; 7:117. [PMID: 29197958 PMCID: PMC5712298 DOI: 10.1186/s13613-017-0339-5] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 11/20/2017] [Indexed: 12/12/2022] Open
Abstract
Host infection by a micro-organism triggers systemic inflammation, innate immunity and complement pathways, but also haemostasis activation. The role of thrombin and fibrin generation in host defence is now recognised, and thrombin has become a partner for survival, while it was seen only as one of the "principal suspects" of multiple organ failure and death during septic shock. This review is first focused on pathophysiology. The role of contact activation system, polyphosphates and neutrophil extracellular traps has emerged, offering new potential therapeutic targets. Interestingly, newly recognised host defence peptides (HDPs), derived from thrombin and other "coagulation" factors, are potent inhibitors of bacterial growth. Inhibition of thrombin generation could promote bacterial growth, while HDPs could become novel therapeutic agents against pathogens when resistance to conventional therapies grows. In a second part, we focused on sepsis-induced coagulopathy diagnostic challenge and stratification from "adaptive" haemostasis to "noxious" disseminated intravascular coagulation (DIC) either thrombotic or haemorrhagic. Besides usual coagulation tests, we discussed cellular haemostasis assessment including neutrophil, platelet and endothelial cell activation. Then, we examined therapeutic opportunities to prevent or to reduce "excess" thrombin generation, while preserving "adaptive" haemostasis. The fail of international randomised trials involving anticoagulants during septic shock may modify the hypothesis considering the end of haemostasis as a target to improve survival. On the one hand, patients at low risk of mortality may not be treated to preserve "immunothrombosis" as a defence when, on the other hand, patients at high risk with patent excess thrombin and fibrin generation could benefit from available (antithrombin, soluble thrombomodulin) or ongoing (FXI and FXII inhibitors) therapies. We propose to better assess coagulation response during infection by an improved knowledge of pathophysiology and systematic testing including determination of DIC scores. This is one of the clues to allocate the right treatment for the right patient at the right moment.
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Affiliation(s)
- Xavier Delabranche
- Université de Strasbourg, Faculté de Médecine & Hôpitaux Universitaires de Strasbourg, Service de Réanimation, Nouvel Hôpital Civil, Strasbourg, France
- INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), FMTS, Université de Strasbourg, Strasbourg, France
| | - Julie Helms
- Université de Strasbourg, Faculté de Médecine & Hôpitaux Universitaires de Strasbourg, Service de Réanimation, Nouvel Hôpital Civil, Strasbourg, France
- INSERM, EFS Grand Est, BPPS UMR-S 949, Université de Strasbourg, Strasbourg, France
| | - Ferhat Meziani
- Université de Strasbourg, Faculté de Médecine & Hôpitaux Universitaires de Strasbourg, Service de Réanimation, Nouvel Hôpital Civil, Strasbourg, France
- INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), FMTS, Université de Strasbourg, Strasbourg, France
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23
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Meuskens I, Michalik M, Chauhan N, Linke D, Leo JC. A New Strain Collection for Improved Expression of Outer Membrane Proteins. Front Cell Infect Microbiol 2017; 7:464. [PMID: 29164072 PMCID: PMC5681912 DOI: 10.3389/fcimb.2017.00464] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/20/2017] [Indexed: 02/02/2023] Open
Abstract
Almost all integral membrane proteins found in the outer membranes of Gram-negative bacteria belong to the transmembrane β-barrel family. These proteins are not only important for nutrient uptake and homeostasis, but are also involved in such processes as adhesion, protein secretion, biofilm formation, and virulence. As surface exposed molecules, outer membrane β-barrel proteins are also potential drug and vaccine targets. High production levels of heterologously expressed proteins are desirable for biochemical and especially structural studies, but over-expression and subsequent purification of membrane proteins, including outer membrane proteins, can be challenging. Here, we present a set of deletion mutants derived from E. coli BL21 Gold (DE3) designed for the over-expression of recombinant outer membrane proteins. These strains harbor deletions of four genes encoding abundant β-barrel proteins in the outer membrane (OmpA, OmpC, OmpF, and LamB), both single and in all combinations of double, triple, and quadruple knock-outs. The sequences encoding these outer membrane proteins were deleted completely, leaving only a minimal scar sequence, thus preventing the possibility of genetic reversion. Expression tests in the quadruple mutant strain with four test proteins, including a small outer membrane β-barrel protein and variants thereof as well as two virulence-related autotransporters, showed significantly improved expression and better quality of the produced proteins over the parent strain. Differences in growth behavior and aggregation in the presence of high salt were observed, but these phenomena did not negatively influence the expression in the quadruple mutant strain when handled as we recommend. The strains produced in this study can be used for outer membrane protein production and purification, but are also uniquely useful for labeling experiments for biophysical measurements in the native membrane environment.
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Affiliation(s)
- Ina Meuskens
- Section for Evolution and Genetics, Department of Biosciences, University of Oslo, Oslo, Norway.,Interfaculty Institute for Biochemistry, Eberhard Karls University, Tübingen, Germany
| | - Marcin Michalik
- Section for Evolution and Genetics, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Nandini Chauhan
- Section for Evolution and Genetics, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Dirk Linke
- Section for Evolution and Genetics, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Jack C Leo
- Section for Evolution and Genetics, Department of Biosciences, University of Oslo, Oslo, Norway
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24
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Wood SE, Sinsinbar G, Gudlur S, Nallani M, Huang CF, Liedberg B, Mrksich M. A Bottom-Up Proteomic Approach to Identify Substrate Specificity of Outer-Membrane Protease OmpT. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201707535] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Sarah E. Wood
- Departments of Chemistry and Biomedical Engineering; Northwestern University; 2145 Sheridan Road Evanston IL 60208 USA
| | - Gaurav Sinsinbar
- Center for Biomimetic Sensor Science; School of Materials Science & Engineering; Nanyang Technological University; 50 Nanyang Drive 637553 Singapore
| | - Sushanth Gudlur
- Center for Biomimetic Sensor Science; School of Materials Science & Engineering; Nanyang Technological University; 50 Nanyang Drive 637553 Singapore
| | - Madhavan Nallani
- Center for Biomimetic Sensor Science; School of Materials Science & Engineering; Nanyang Technological University; 50 Nanyang Drive 637553 Singapore
| | - Che-Fan Huang
- Departments of Chemistry and Biomedical Engineering; Northwestern University; 2145 Sheridan Road Evanston IL 60208 USA
| | - Bo Liedberg
- Center for Biomimetic Sensor Science; School of Materials Science & Engineering; Nanyang Technological University; 50 Nanyang Drive 637553 Singapore
| | - Milan Mrksich
- Departments of Chemistry and Biomedical Engineering; Northwestern University; 2145 Sheridan Road Evanston IL 60208 USA
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25
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Wood SE, Sinsinbar G, Gudlur S, Nallani M, Huang CF, Liedberg B, Mrksich M. A Bottom-Up Proteomic Approach to Identify Substrate Specificity of Outer-Membrane Protease OmpT. Angew Chem Int Ed Engl 2017; 56:16531-16535. [DOI: 10.1002/anie.201707535] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/06/2017] [Indexed: 12/22/2022]
Affiliation(s)
- Sarah E. Wood
- Departments of Chemistry and Biomedical Engineering; Northwestern University; 2145 Sheridan Road Evanston IL 60208 USA
| | - Gaurav Sinsinbar
- Center for Biomimetic Sensor Science; School of Materials Science & Engineering; Nanyang Technological University; 50 Nanyang Drive 637553 Singapore
| | - Sushanth Gudlur
- Center for Biomimetic Sensor Science; School of Materials Science & Engineering; Nanyang Technological University; 50 Nanyang Drive 637553 Singapore
| | - Madhavan Nallani
- Center for Biomimetic Sensor Science; School of Materials Science & Engineering; Nanyang Technological University; 50 Nanyang Drive 637553 Singapore
| | - Che-Fan Huang
- Departments of Chemistry and Biomedical Engineering; Northwestern University; 2145 Sheridan Road Evanston IL 60208 USA
| | - Bo Liedberg
- Center for Biomimetic Sensor Science; School of Materials Science & Engineering; Nanyang Technological University; 50 Nanyang Drive 637553 Singapore
| | - Milan Mrksich
- Departments of Chemistry and Biomedical Engineering; Northwestern University; 2145 Sheridan Road Evanston IL 60208 USA
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Pane K, Durante L, Crescenzi O, Cafaro V, Pizzo E, Varcamonti M, Zanfardino A, Izzo V, Di Donato A, Notomista E. Antimicrobial potency of cationic antimicrobial peptides can be predicted from their amino acid composition: Application to the detection of “cryptic” antimicrobial peptides. J Theor Biol 2017; 419:254-265. [DOI: 10.1016/j.jtbi.2017.02.012] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 01/23/2017] [Accepted: 02/11/2017] [Indexed: 10/20/2022]
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Abstract
Proteinases play a crucial role in invasion and pathogenesis of bacteria, especially the extracellular and membrane-bound forms. Analysis of these proteinases demands the isolation by retaining the enzymatic activity. The isolation procedures maintaining the native structure of the enzyme in its soluble form are also of extreme importance. The qualitative analyses of these proteinases are carried out by electrophoresis and zymography. Enzymatic characterization based on the effect of inhibitors and activators on gelatinase activity also can be assessed using this zymography. The membrane-bound proteinases can be isolated in their native and soluble form, still retaining the activity using 6-aminocaproic acid and sodium deoxycholate; the procedure of which is explained in this chapter.
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Affiliation(s)
- Madathiparambil G Madanan
- Regional Medical Research Centre, Indian Council of Medical Research, Port Blair, 744103, Andaman & Nicobar Islands, India.
| | - Ambili Mechoor
- Department of Biotechnology Engineering, Sahrdaya College of Engineering and Technology, Kodakara, Thrissur, 680684, Kerala, India
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Two Isoforms of Yersinia pestis Plasminogen Activator Pla: Intraspecies Distribution, Intrinsic Disorder Propensity, and Contribution to Virulence. PLoS One 2016; 11:e0168089. [PMID: 27936190 PMCID: PMC5148098 DOI: 10.1371/journal.pone.0168089] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 11/25/2016] [Indexed: 12/12/2022] Open
Abstract
It has been shown previously that several endemic Y. pestis isolates with limited virulence contained the I259 isoform of the outer membrane protease Pla, while the epidemic highly virulent strains possessed only the T259 Pla isoform. Our sequence analysis of the pla gene from 118 Y. pestis subsp. microtus strains revealed that the I259 isoform was present exclusively in the endemic strains providing a convictive evidence of more ancestral origin of this isoform. Analysis of the effects of the I259T polymorphism on the intrinsic disorder propensity of Pla revealed that the I259T mutation slightly increases the intrinsic disorder propensity of the C-terminal tail of Pla and makes this protein slightly more prone for disorder-based protein-protein interactions, suggesting that the T259 Pla could be functionally more active than the I259 Pla. This assumption was proven experimentally by assessing the coagulase and fibrinolytic activities of the two Pla isoforms in human plasma, as well as in a direct fluorometric assay with the Pla peptide substrate. The virulence testing of Pla-negative or expressing the I259 and T259 Pla isoforms Y. pestis subsp. microtus and subsp. pestis strains did not reveal any significant difference in LD50 values and dose-dependent survival assays between them by using a subcutaneous route of challenge of mice and guinea pigs or intradermal challenge of mice. However, a significant decrease in time-to-death was observed in animals infected with the epidemic T259 Pla-producing strains as compared to the parent Pla-negative variants. Survival curves of the endemic I259 Pla+ strains fit between them, but significant difference in mean time to death post infection between the Pla−strains and their I259 Pla+ variants could be seen only in the isogenic set of subsp. pestis strains. These findings suggest an essential role for the outer membrane protease Pla evolution in Y. pestis bubonic infection exacerbation that is necessary for intensification of epidemic process from endemic natural focality with sporadic cases in men to rapidly expanding epizootics followed by human epidemic outbreaks, local epidemics or even pandemics.
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mTORC1-Activated Monocytes Increase Tregs and Inhibit the Immune Response to Bacterial Infections. Mediators Inflamm 2016; 2016:7369351. [PMID: 27746591 PMCID: PMC5056273 DOI: 10.1155/2016/7369351] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 08/05/2016] [Accepted: 08/11/2016] [Indexed: 02/07/2023] Open
Abstract
The TSC1/2 heterodimer, a key upstream regulator of the mTOR, can inhibit the activation of mTOR, which plays a critical role in immune responses after bacterial infections. Monocytes are an innate immune cell type that have been shown to be involved in bacteremia. However, how the mTOR pathway is involved in the regulation of monocytes is largely unknown. In our study, TSC1 KO mice and WT mice were infected with E. coli. When compared to WT mice, we found higher mortality, greater numbers of bacteria, decreased expression of coactivators in monocytes, increased numbers of Tregs, and decreased numbers of effector T cells in TSC1 KO mice. Monocytes obtained from TSC1 KO mice produced more ROS, IL-6, IL-10, and TGF-β and less IL-1, IFN-γ, and TNF-α. Taken together, our results suggest that the inhibited immune functioning in TSC1 KO mice is influenced by mTORC1 activation in monocytes. The reduced expression of coactivators resulted in inhibited effector T cell proliferation. mTORC1-activated monocytes are harmful during bacterial infections. Therefore, inhibiting mTORC1 signaling through rapamycin administration could rescue the harmful aspects of an overactive immune response, and this knowledge provides a new direction for clinical therapy.
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30
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Microbiomic and Posttranslational Modifications as Preludes to Autoimmune Diseases. Trends Mol Med 2016; 22:746-757. [DOI: 10.1016/j.molmed.2016.07.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 07/08/2016] [Accepted: 07/11/2016] [Indexed: 01/08/2023]
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31
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Kylväjä R, Ojalehto T, Kainulainen V, Virkola R, Westerlund-Wikström B. Penicillin binding protein 3 of Staphylococcus aureus NCTC 8325-4 binds and activates human plasminogen. BMC Res Notes 2016; 9:389. [PMID: 27488131 PMCID: PMC4972960 DOI: 10.1186/s13104-016-2190-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/28/2016] [Indexed: 11/25/2022] Open
Abstract
Background Staphylococcus aureus is a versatile pathogen expressing a number of virulence-associated adhesive molecules. In a previous study, we generated in a secretion-competent Escherichia coli strain a library of random FLAG-tag positive (FTP) polypeptides of S. aureus. To identify adhesive proteins and gain additional knowledge on putative virulence factors of S. aureus, we here screened the FTP library against human serum proteins. Findings Staphylococcus aureus NCTC 8325-4, origin of the FTP library, adhered to immobilized plasminogen in vitro. In an enzyme-linked immunoassay a C-terminal part of penicillin binding protein 3 (PBP3), included in the FTP library, bound to immobilized plasminogen. We expressed and purified full-length PBP3 and its C-terminal fragments as recombinant proteins. In a time-resolved fluorometry—based assay the PBP3 polypeptides bound to immobilized plasminogen. The polypeptides enhanced formation of plasmin from plasminogen as analyzed by cleavage of a chromogenic plasmin substrate. Conclusions The present findings, although preliminary, demonstrate reliably that S. aureus NCTC 8325-4 adheres to immobilized plasminogen in vitro and that the adhesion may be mediated by a C-terminal fragment of the PBP3 protein. The full length PBP3 and the penicillin binding C-terminal domain of PBP3 expressed as recombinant proteins bound plasminogen and activated plasminogen to plasmin. These phenomena were inhibited by the lysine analogue ε-aminocaproic acid suggesting that the binding is mediated by lysine residues. A detailed molecular description of surface molecules enhancing the virulence of S. aureus will aid in understanding of its pathogenicity and help in design of antibacterial drugs in the future. Electronic supplementary material The online version of this article (doi:10.1186/s13104-016-2190-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Riikka Kylväjä
- General Microbiology, Department of Biosciences, University of Helsinki, P.O.Box 56, FI-00014, University of Helsinki, Helsinki, Finland.,Thermo Fisher Scientific, Ratastie 2, 01620, Vantaa, Finland
| | - Tuomas Ojalehto
- General Microbiology, Department of Biosciences, University of Helsinki, P.O.Box 56, FI-00014, University of Helsinki, Helsinki, Finland.,Orion Diagnostica, Koivu-Mankkaan tie 6, 02200, Espoo, Finland
| | - Veera Kainulainen
- General Microbiology, Department of Biosciences, University of Helsinki, P.O.Box 56, FI-00014, University of Helsinki, Helsinki, Finland.,Pharmacology, Faculty of Medicine, University of Helsinki, P.O.Box 63, FI-00014, University of Helsinki, Helsinki, Finland
| | - Ritva Virkola
- General Microbiology, Department of Biosciences, University of Helsinki, P.O.Box 56, FI-00014, University of Helsinki, Helsinki, Finland
| | - Benita Westerlund-Wikström
- General Microbiology, Department of Biosciences, University of Helsinki, P.O.Box 56, FI-00014, University of Helsinki, Helsinki, Finland.
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32
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Joo HS, Fu CI, Otto M. Bacterial strategies of resistance to antimicrobial peptides. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150292. [PMID: 27160595 PMCID: PMC4874390 DOI: 10.1098/rstb.2015.0292] [Citation(s) in RCA: 213] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2016] [Indexed: 02/06/2023] Open
Abstract
Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.
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Affiliation(s)
- Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Chih-Iung Fu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
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33
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Joo HS, Fu CI, Otto M. Bacterial strategies of resistance to antimicrobial peptides. Philos Trans R Soc Lond B Biol Sci 2016. [PMID: 27160595 DOI: 10.1098/rstb.2015.0292.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.
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Affiliation(s)
- Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Chih-Iung Fu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
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Chauhan N, Wrobel A, Skurnik M, Leo JC. Yersinia adhesins: An arsenal for infection. Proteomics Clin Appl 2016; 10:949-963. [PMID: 27068449 DOI: 10.1002/prca.201600012] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/14/2016] [Accepted: 04/06/2016] [Indexed: 11/09/2022]
Abstract
The Yersiniae are a group of Gram-negative coccobacilli inhabiting a wide range of habitats. The genus harbors three recognized human pathogens: Y. enterocolitica and Y. pseudotuberculosis, which both cause gastrointestinal disease, and Y. pestis, the causative agent of plague. These three organisms have served as models for a number of aspects of infection biology, including adhesion, immune evasion, evolution of pathogenic traits, and retracing the course of ancient pandemics. The virulence of the pathogenic Yersiniae is heavily dependent on a number of adhesin molecules. Some of these, such as the Yersinia adhesin A and invasin of the enteropathogenic species, and the pH 6 antigen of Y. pestis, have been extensively studied. However, genomic sequencing has uncovered a host of other adhesins present in these organisms, the functions of which are only starting to be investigated. Here, we review the current state of knowledge on the adhesin molecules present in the Yersiniae, and their functions and putative roles in the infection process.
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Affiliation(s)
- Nandini Chauhan
- Evolution and Genetics, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Agnieszka Wrobel
- Evolution and Genetics, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Mikael Skurnik
- Department of Bacteriology and Immunology, Medicum, Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland.,Central Hospital Laboratory Diagnostics, Helsinki University, Helsinki, Finland
| | - Jack C Leo
- Evolution and Genetics, Department of Biosciences, University of Oslo, Oslo, Norway.
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Armougom F, Bitam I, Croce O, Merhej V, Barassi L, Nguyen TT, La Scola B, Raoult D. Genomic Insights into a New Citrobacter koseri Strain Revealed Gene Exchanges with the Virulence-Associated Yersinia pestis pPCP1 Plasmid. Front Microbiol 2016; 7:340. [PMID: 27014253 PMCID: PMC4793686 DOI: 10.3389/fmicb.2016.00340] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/03/2016] [Indexed: 01/10/2023] Open
Abstract
The history of infectious diseases raised the plague as one of the most devastating for human beings. Far too often considered an ancient disease, the frequent resurgence of the plague has led to consider it as a reemerging disease in Madagascar, Algeria, Libya, and Congo. The genetic factors associated with the pathogenicity of Yersinia pestis, the causative agent of the plague, involve the acquisition of the pPCP1 plasmid that promotes host invasion through the expression of the virulence factor Pla. The surveillance of plague foci after the 2003 outbreak in Algeria resulted in a positive detection of the specific pla gene of Y. pestis in rodents. However, the phenotypic characterization of the isolate identified a Citrobacter koseri. The comparative genomics of our sequenced C. koseri URMITE genome revealed a mosaic gene structure resulting from the lifestyle of our isolate and provided evidence for gene exchanges with different enteric bacteria. The most striking was the acquisition of a continuous 2 kb genomic fragment containing the virulence factor Pla of the Y. pestis pPCP1 plasmid; however, the subcutaneous injection of the CKU strain in mice did not produce any pathogenic effect. Our findings demonstrate that fast molecular detection of plague using solely the pla gene is unsuitable and should rather require Y. pestis gene marker combinations. We also suggest that the evolutionary force that might govern the expression of pathogenicity can occur through the acquisition of virulence genes but could also require the loss or the inactivation of resident genes such as antivirulence genes.
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Affiliation(s)
- Fabrice Armougom
- URMITE, Faculté de Médecine, Centre National de la Recherche Scientifique UM63, CNRS 7257, IRD198, Institut National de la Santé et de la Recherche Médicale 1095, Aix-Marseille UniversitéMarseille, France; Centre National de la Recherche Scientifique, IRD, Mediterranean Institute of Oceanography, Aix Marseille Université, Université de Toulon, UM110Marseille, France
| | - Idir Bitam
- Laboratoire VALCORE, Université M'Hamed Bougara Boumerdès Boumerdès, Algeria
| | - Olivier Croce
- URMITE, Faculté de Médecine, Centre National de la Recherche Scientifique UM63, CNRS 7257, IRD198, Institut National de la Santé et de la Recherche Médicale 1095, Aix-Marseille Université Marseille, France
| | - Vicky Merhej
- URMITE, Faculté de Médecine, Centre National de la Recherche Scientifique UM63, CNRS 7257, IRD198, Institut National de la Santé et de la Recherche Médicale 1095, Aix-Marseille Université Marseille, France
| | - Lina Barassi
- URMITE, Faculté de Médecine, Centre National de la Recherche Scientifique UM63, CNRS 7257, IRD198, Institut National de la Santé et de la Recherche Médicale 1095, Aix-Marseille Université Marseille, France
| | - Ti-Thien Nguyen
- URMITE, Faculté de Médecine, Centre National de la Recherche Scientifique UM63, CNRS 7257, IRD198, Institut National de la Santé et de la Recherche Médicale 1095, Aix-Marseille Université Marseille, France
| | - Bernard La Scola
- URMITE, Faculté de Médecine, Centre National de la Recherche Scientifique UM63, CNRS 7257, IRD198, Institut National de la Santé et de la Recherche Médicale 1095, Aix-Marseille Université Marseille, France
| | - Didier Raoult
- URMITE, Faculté de Médecine, Centre National de la Recherche Scientifique UM63, CNRS 7257, IRD198, Institut National de la Santé et de la Recherche Médicale 1095, Aix-Marseille Université Marseille, France
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Guinet F, Avé P, Filali S, Huon C, Savin C, Huerre M, Fiette L, Carniel E. Dissociation of Tissue Destruction and Bacterial Expansion during Bubonic Plague. PLoS Pathog 2015; 11:e1005222. [PMID: 26484539 PMCID: PMC4615631 DOI: 10.1371/journal.ppat.1005222] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 09/22/2015] [Indexed: 01/14/2023] Open
Abstract
Activation and/or recruitment of the host plasmin, a fibrinolytic enzyme also active on extracellular matrix components, is a common invasive strategy of bacterial pathogens. Yersinia pestis, the bubonic plague agent, expresses the multifunctional surface protease Pla, which activates plasmin and inactivates fibrinolysis inhibitors. Pla is encoded by the pPla plasmid. Following intradermal inoculation, Y. pestis has the capacity to multiply in and cause destruction of the lymph node (LN) draining the entry site. The closely related, pPla-negative, Y. pseudotuberculosis species lacks this capacity. We hypothesized that tissue damage and bacterial multiplication occurring in the LN during bubonic plague were linked and both driven by pPla. Using a set of pPla-positive and pPla-negative Y. pestis and Y. pseudotuberculosis strains in a mouse model of intradermal injection, we found that pPla is not required for bacterial translocation to the LN. We also observed that a pPla-cured Y. pestis caused the same extensive histological lesions as the wild type strain. Furthermore, the Y. pseudotuberculosis histological pattern, characterized by infectious foci limited by inflammatory cell infiltrates with normal tissue density and follicular organization, was unchanged after introduction of pPla. However, the presence of pPla enabled Y. pseudotuberculosis to increase its bacterial load up to that of Y. pestis. Similarly, lack of pPla strongly reduced Y. pestis titers in LNs of infected mice. This pPla-mediated enhancing effect on bacterial load was directly dependent on the proteolytic activity of Pla. Immunohistochemistry of Pla-negative Y. pestis-infected LNs revealed extensive bacterial lysis, unlike the numerous, apparently intact, microorganisms seen in wild type Y. pestis-infected preparations. Therefore, our study demonstrates that tissue destruction and bacterial survival/multiplication are dissociated in the bubo and that the primary action of Pla is to protect bacteria from destruction rather than to alter the tissue environment to favor Y. pestis propagation in the host. The hallmark of bubonic plague, a disease that ravaged Medieval Europe and is still prevalent in several countries, is the bubo, a highly inflammatory and painful lymph node, which is characterized by high concentrations of bacteria within a severely damaged organ. Yersinia pestis, the causative agent, expresses a surface protease, Pla, critical to the development of bubonic plague. This multitarget protease has the potential to activate the fibrinolytic pathway and to promote destruction of extracellular protein networks within tissues. Hence, it was expected that Pla was responsible for the tissue destructions of the bubo, and consequently, for bacterial propagation and virulence. However, we found, using various engineered Yersinia strains in a mouse model of bubonic plague, that Pla proteolytic activity was dispensable for lymph node alteration, but was required to achieve high bacterial loads in the organ. Further analysis showed that Pla is essential for preventing the bacteria from being destroyed in the host. Therefore, the role of Pla as a virulence factor is to protect Y. pestis survival and integrity in the host, rather than to assist its spread through tissue destruction.
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Affiliation(s)
- Françoise Guinet
- Unité de Recherche Yersinia, Institut Pasteur, Paris, France
- * E-mail: (FG); (EC)
| | - Patrick Avé
- Unité d’Histopathologie Humaine et Modèles Animaux, Institut Pasteur, Paris, France
| | - Sofia Filali
- Unité de Recherche Yersinia, Institut Pasteur, Paris, France
| | - Christèle Huon
- Unité de Recherche Yersinia, Institut Pasteur, Paris, France
| | - Cyril Savin
- Unité de Recherche Yersinia, Institut Pasteur, Paris, France
| | - Michel Huerre
- Unité de Recherche et d’Expertise d’Histotechnologie et Pathologie, Institut Pasteur, Paris, France
| | - Laurence Fiette
- Unité d’Histopathologie Humaine et Modèles Animaux, Institut Pasteur, Paris, France
| | - Elisabeth Carniel
- Unité de Recherche Yersinia, Institut Pasteur, Paris, France
- * E-mail: (FG); (EC)
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Peetermans M, Vanassche T, Liesenborghs L, Lijnen RH, Verhamme P. Bacterial pathogens activate plasminogen to breach tissue barriers and escape from innate immunity. Crit Rev Microbiol 2015; 42:866-82. [PMID: 26485450 DOI: 10.3109/1040841x.2015.1080214] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Both coagulation and fibrinolysis are tightly connected with the innate immune system. Infection and inflammation cause profound alterations in the otherwise well-controlled balance between coagulation and fibrinolysis. Many pathogenic bacteria directly exploit the host's hemostatic system to increase their virulence. Here, we review the capacity of bacteria to activate plasminogen. The resulting proteolytic activity allows them to breach tissue barriers and evade innate immune defense, thus promoting bacterial spreading. Yersinia pestis, streptococci of group A, C and G and Staphylococcus aureus produce a specific bacterial plasminogen activator. Moreover, surface plasminogen receptors play an established role in pneumococcal, borrelial and group B streptococcal infections. This review summarizes the mechanisms of bacterial activation of host plasminogen and the role of the fibrinolytic system in infections caused by these pathogens.
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Affiliation(s)
- Marijke Peetermans
- a Center for Molecular and Vascular Biology, KU Leuven , Leuven , Belgium
| | - Thomas Vanassche
- a Center for Molecular and Vascular Biology, KU Leuven , Leuven , Belgium
| | | | - Roger H Lijnen
- a Center for Molecular and Vascular Biology, KU Leuven , Leuven , Belgium
| | - Peter Verhamme
- a Center for Molecular and Vascular Biology, KU Leuven , Leuven , Belgium
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Antimicrobial Peptide Conformation as a Structural Determinant of Omptin Protease Specificity. J Bacteriol 2015; 197:3583-91. [PMID: 26350132 DOI: 10.1128/jb.00469-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 08/28/2015] [Indexed: 01/05/2023] Open
Abstract
UNLABELLED Bacterial proteases contribute to virulence by cleaving host or bacterial proteins to promote survival and dissemination. Omptins are a family of proteases embedded in the outer membrane of Gram-negative bacteria that cleave various substrates, including host antimicrobial peptides, with a preference for cleaving at dibasic motifs. OmpT, the enterohemorrhagic Escherichia coli (EHEC) omptin, cleaves and inactivates the human cathelicidin LL-37. Similarly, the omptin CroP, found in the murine pathogen Citrobacter rodentium, which is used as a surrogate model to study human-restricted EHEC, cleaves the murine cathelicidin-related antimicrobial peptide (CRAMP). Here, we compared the abilities of OmpT and CroP to cleave LL-37 and CRAMP. EHEC OmpT degraded LL-37 and CRAMP at similar rates. In contrast, C. rodentium CroP cleaved CRAMP more rapidly than LL-37. The different cleavage rates of LL-37 and CRAMP were independent of the bacterial background and substrate sequence specificity, as OmpT and CroP have the same preference for cleaving at dibasic sites. Importantly, LL-37 was α-helical and CRAMP was unstructured under our experimental conditions. By altering the α-helicity of LL-37 and CRAMP, we found that decreasing LL-37 α-helicity increased its rate of cleavage by CroP. Conversely, increasing CRAMP α-helicity decreased its cleavage rate. This structural basis for CroP substrate specificity highlights differences between the closely related omptins of C. rodentium and E. coli. In agreement with previous studies, this difference in CroP and OmpT substrate specificity suggests that omptins evolved in response to the substrates present in their host microenvironments. IMPORTANCE Omptins are recognized as key virulence factors for various Gram-negative pathogens. Their localization to the outer membrane, their active site facing the extracellular environment, and their unique catalytic mechanism make them attractive targets for novel therapeutic strategies. Gaining insights into similarities and variations between the different omptin active sites and subsequent substrate specificities will be critical to develop inhibitors that can target multiple omptins. Here, we describe subtle differences between the substrate specificities of two closely related omptins, CroP and OmpT. This is the first reported example of substrate conformation acting as a structural determinant for omptin activity between OmpT-like proteases.
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Kulkarni HM, Nagaraj R, Jagannadham MV. Protective role of E. coli outer membrane vesicles against antibiotics. Microbiol Res 2015; 181:1-7. [PMID: 26640046 DOI: 10.1016/j.micres.2015.07.008] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 07/17/2015] [Accepted: 07/24/2015] [Indexed: 12/19/2022]
Abstract
The outer membrane vesicles (OMVs) from bacteria are known to posses both defensive and protective functions and thus participate in community related functions. In the present study, outer membrane vesicles have been shown to protect the producer bacterium and two other bacterial species from the growth inhibitory effects of some antibiotics. The OMVs isolated from E. coli MG1655 protected the bacteria against membrane-active antibiotics colistin, melittin. The OMVs of E. coli MG1655 could also protect P. aeruginosa NCTC6751 and A. radiodioresistens MMC5 against these membrane-active antibiotics. However, OMVs could not protect any of these bacteria against the other antibiotics ciprofloxacin, streptomycin and trimethoprim. Hence, OMVs appears to protect the bacterial community against membrane-active antibiotics and not other antibiotics, which have different mechanism of actions. The OMVs of E. coli MG1655 sequester the antibiotic colistin, whereas their protein components degrade the antimicrobial peptide melittin. Proteomic analysis of OMVs revealed the presence of proteases and peptidases which appear to be involved in this process. Thus, the protection of bacteria by OMVs against antibiotics is situation dependent and the mechanism differs for different situations. These studies suggest that OMVs of bacteria form a common defense for the bacterial community against specific antibiotics.
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Affiliation(s)
- Heramb M Kulkarni
- CSIR- Centre for Cellular and Molecular Biology, Tarnaka, Hyderabad 500007, India
| | - R Nagaraj
- CSIR- Centre for Cellular and Molecular Biology, Tarnaka, Hyderabad 500007, India
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Korhonen TK. Fibrinolytic and procoagulant activities of Yersinia pestis and Salmonella enterica. J Thromb Haemost 2015; 13 Suppl 1:S115-20. [PMID: 26149012 DOI: 10.1111/jth.12932] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Pla of the plague bacterium Yersinia pestis and PgtE of the enteropathogen Salmonella enterica are surface-exposed, transmembrane β-barrel proteases of the omptin family that exhibit a complex array of interactions with the hemostatic systems in vitro, and both proteases are established virulence factors. Pla favors fibrinolysis by direct activation of plasminogen, inactivation of the serpins plasminogen activator inhibitor-1 and α2-antiplasmin, inactivation of the thrombin-activable fibrinolysis inhibitor, and activation of single-chain urokinase. PgtE is structurally very similar but exhibits partially different functions and differ in expression control. PgtE proteolysis targets control aspects of fibrinolysis, and mimicry of matrix metalloproteinases enhances cell migration that should favor the intracellular spread of the bacterium. Enzymatic activity of both proteases is strongly influenced by the environment-induced variations in lipopolysaccharide that binds to the β-barrel. Both proteases cleave the tissue factor pathway inhibitor and thus also express procoagulant activity.
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Affiliation(s)
- T K Korhonen
- General Microbiology, Department of Biosciences, University of Helsinki, Helsinki, Finland
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Mucosal physical and chemical innate barriers: Lessons from microbial evasion strategies. Semin Immunol 2015; 27:111-8. [PMID: 25936225 DOI: 10.1016/j.smim.2015.03.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 03/13/2015] [Indexed: 12/24/2022]
Abstract
The innate immune system has evolved since millions of years under a selective pressure. Among the different host mechanisms selected and conserved as a first line of defense, the gastrointestinal mucus layer constitutes an efficient physical and chemical barrier against invading microbes. Mucin glycoproteins and antimicrobial peptides are the major components of the mucus barrier, and evidences prove that they form an effective protection against most microbes. However, successful pathogens have evolved evasion strategies to circumvent this defense barrier. Here, we discuss the interactions between pathogens, mucins, and antimicrobial peptides, and the mechanisms that pathogens have developed to evade the innate defense systems of the intestinal mucosal barrier.
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Inhibition of outer membrane proteases of the omptin family by aprotinin. Infect Immun 2015; 83:2300-11. [PMID: 25824836 DOI: 10.1128/iai.00136-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 03/20/2015] [Indexed: 12/14/2022] Open
Abstract
Bacterial proteases are important virulence factors that inactivate host defense proteins and contribute to tissue destruction and bacterial dissemination. Outer membrane proteases of the omptin family, exemplified by Escherichia coli OmpT, are found in some Gram-negative bacteria. Omptins cleave a variety of substrates at the host-pathogen interface, including plasminogen and antimicrobial peptides. Multiple omptin substrates relevant to infection have been identified; nonetheless, an effective omptin inhibitor remains to be found. Here, we purified native CroP, the OmpT ortholog in the murine pathogen Citrobacter rodentium. Purified CroP was found to readily cleave both a synthetic fluorescence resonance energy transfer substrate and the murine cathelicidin-related antimicrobial peptide. In contrast, CroP was found to poorly activate plasminogen into active plasmin. Although classical protease inhibitors were ineffective against CroP activity, we found that the serine protease inhibitor aprotinin displays inhibitory potency in the micromolar range. Aprotinin was shown to act as a competitive inhibitor of CroP activity and to interfere with the cleavage of the murine cathelicidin-related antimicrobial peptide. Importantly, aprotinin was able to inhibit not only CroP but also Yersinia pestis Pla and, to a lesser extent, E. coli OmpT. We propose a structural model of the aprotinin-omptin complex in which Lys15 of aprotinin forms salt bridges with conserved negatively charged residues of the omptin active site.
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He XL, Wang Q, Peng L, Qu YR, Puthiyakunnon S, Liu XL, Hui CY, Boddu S, Cao H, Huang SH. Role of uropathogenic Escherichia coli outer membrane protein T in pathogenesis of urinary tract infection. Pathog Dis 2015; 73:ftv006. [PMID: 25825479 DOI: 10.1093/femspd/ftv006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
OmpT is one of the members of the outer membrane protein family that has been identified as a virulence factor in most of the uropathogenic Escherichia coli (UPEC). However, the exact role of OmpT in the urinary tract infections (UTIs) remains unclear. To determine the role of OmpT in the pathogenesis of UPEC, an isogenic deletion mutant of ompT (COTD) was constructed by the λ Red recombination. Human bladder epithelial cell line 5637(HBEC 5637) was used to evaluate the ability of bacterial adhesion/invasion. A murine model of UTI was established to study the formation of intracellular bacterial communities (IBCs) in the process of UTIs. The cytokines were also examined during the pathogenesis. The results showed that the COTD strain was deficient in bacterial adhesion and invasion as well as in IBC formation compare to the parent strain. ELISA quantification analysis of cytokines showed that the levels of TNF-α, IL-6 and IL-8 in the serum, bladder and kidney tissues of the mice infected with COTD were lower than that of the CFT073 group. In summary, these results suggest that OmpT plays a multifaceted role in pathogenesis of UTI, including increased bacterial adhesiveness/invasiveness, formation of IBCs and upregulated proinflammatory cytokines.
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Affiliation(s)
- Xiao Long He
- Department of Microbiology, School of Public Health & Tropical Medicine, Southern Medical University, Guangzhou 510515, China
| | - Qin Wang
- Department of Microbiology, School of Public Health & Tropical Medicine, Southern Medical University, Guangzhou 510515, China
| | - Liang Peng
- Department of Clinical Laboratory, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260 China
| | - Ya-Rong Qu
- Department of Microbiology, School of Public Health & Tropical Medicine, Southern Medical University, Guangzhou 510515, China
| | - Santhosh Puthiyakunnon
- Department of Microbiology, School of Public Health & Tropical Medicine, Southern Medical University, Guangzhou 510515, China
| | - Xiao-Lu Liu
- Department of Microbiology, School of Public Health & Tropical Medicine, Southern Medical University, Guangzhou 510515, China
| | - Chang Ye Hui
- Shenzhen Prevention and Treatment Center for Occupational Disease, Shenzhen, Guangdong 518001, China
| | - Swapna Boddu
- Department of Microbiology, School of Public Health & Tropical Medicine, Southern Medical University, Guangzhou 510515, China
| | - Hong Cao
- Department of Microbiology, School of Public Health & Tropical Medicine, Southern Medical University, Guangzhou 510515, China
| | - Sheng-He Huang
- Department of Microbiology, School of Public Health & Tropical Medicine, Southern Medical University, Guangzhou 510515, China Children's Hospital Los Angeles, University of Southern California, Los Angeles 90027, USA
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Premjani V, Tilley D, Gruenheid S, Le Moual H, Samis JA. Enterohemorrhagic Escherichia coli OmpT regulates outer membrane vesicle biogenesis. FEMS Microbiol Lett 2014; 355:185-92. [PMID: 24813639 DOI: 10.1111/1574-6968.12463] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 05/05/2014] [Accepted: 05/06/2014] [Indexed: 12/20/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) infection from food or water often results in severe diarrheal disease and is a leading cause of death globally. Outer membrane vesicles (OMVs) secreted from E. coli induce lethality in mice. The omptin outer membrane protease OmpT from E. coli inactivates antimicrobial peptides and may enhance colonization of the uroepithelium, but its precise function remains unclear. Given OmpT is an outer membrane protease, we hypothesized it may have a role in OMV biogenesis. To further characterize the effect of OmpT on OMV production, a genetic approach using wild type, an ompT deletion mutant and an ompT overexpressing construct in EHEC were employed. ompT gene deletion markedly decreased OMV production and stainable lipid but increased vesicle diameter. Conversely, ompT overexpression profoundly increased OMV biogenesis but decreased stainable lipid, protein content, and vesicle diameter. Alterations in EHEC ompT gene expression have an impact on the biogenesis, composition, and size of OMVs. Changes in ompT gene expression may dynamically alter OMV formation, composition, and diameter in response to different host environments and contribute to cell-free intercellular communication to enhance bacterial growth and survival.
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Affiliation(s)
- Veena Premjani
- Applied Biosciences Program, Faculty of Science, University of Ontario Institute of Technology, Oshawa, ON, Canada
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Host defense peptide resistance contributes to colonization and maximal intestinal pathology by Crohn's disease-associated adherent-invasive Escherichia coli. Infect Immun 2014; 82:3383-93. [PMID: 24866805 DOI: 10.1128/iai.01888-14] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Host defense peptides secreted by colonocytes and Paneth cells play a key role in innate host defenses in the gut. In Crohn's disease, the burden of tissue-associated Escherichia coli commonly increases at epithelial surfaces where host defense peptides concentrate, suggesting that this bacterial population might actively resist this mechanism of bacterial killing. Adherent-invasive E. coli (AIEC) is associated with Crohn's disease; however, the colonization determinants of AIEC in the inflamed gut are undefined. Here, we establish that host defense peptide resistance contributes to host colonization by Crohn's-associated AIEC. We identified a plasmid-encoded genomic island (called PI-6) in AIEC strain NRG857c that confers high-level resistance to α-helical cationic peptides and α- and β-defensins. Deletion of PI-6 sensitized strain NRG857c to these host defense molecules, reduced its competitive fitness in a mouse model of infection, and attenuated its ability to induce cecal pathology. This phenotype is due to two genes in PI-6, arlA, which encodes a Mig-14 family protein implicated in defensin resistance, and arlC, an OmpT family outer membrane protease. Implicit in these findings are new bacterial targets whose inhibition might limit AIEC burden and disease in the gut.
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THE INNATE IMMUNE RESPONSE MAY BE IMPORTANT FOR SURVIVING PLAGUE IN WILD GUNNISON'S PRAIRIE DOGS. J Wildl Dis 2013; 49:920-31. [DOI: 10.7589/2012-08-209] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Korhonen TK, Haiko J, Laakkonen L, Järvinen HM, Westerlund-Wikström B. Fibrinolytic and coagulative activities of Yersinia pestis. Front Cell Infect Microbiol 2013; 3:35. [PMID: 23898467 PMCID: PMC3724046 DOI: 10.3389/fcimb.2013.00035] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2012] [Accepted: 07/09/2013] [Indexed: 12/18/2022] Open
Abstract
The outer membrane protease Pla belongs to the omptin protease family spread by horizontal gene transfer into Gram-negative bacteria that infect animals or plants. Pla has adapted to support the life style of the plague bacterium Yersinia pestis. Pla has a β-barrel fold with 10 membrane-spanning β strands and five surface loops, and the barrel surface contains bound lipopolysaccharide (LPS) that is critical for the conformation and the activity of Pla. The biological activity of Pla is influenced by the structure of the surface loops around the active site groove and by temperature-induced LPS modifications. Several of the putative virulence-related functions documented for Pla in vitro address control of the human hemostatic system, i.e., coagulation and fibrinolysis. Pla activates human plasminogen to the serine protease plasmin and activates the physiological plasminogen activator urokinase. Pla also inactivates the protease inhibitors alpha-2-antiplasmin and plasminogen activator inhibitor 1 (PAI-1) and prevents the activation of thrombin-activatable fibrinolysis inhibitor (TAFI). These functions enhance uncontrolled fibrinolysis which is thought to improve Y. pestis dissemination and survival in the mammalian host, and lowered fibrin(ogen) deposition has indeed been observed in mice infected with Pla-positive Y. pestis. However, Pla also inactivates an anticoagulant, the tissue factor (TF) pathway inhibitor, which should increase fibrin formation and clotting. Thus, Pla and Y. pestis have complex interactions with the hemostatic system. Y. pestis modifies its LPS upon transfer to the mammalian host and we hypothesize that the contrasting biological activities of Pla in coagulation and fibrinolysis are influenced by LPS changes during infection.
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Affiliation(s)
- Timo K Korhonen
- General Microbiology, Department of Biosciences, University of Helsinki Helsinki, Finland.
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Järvinen HM, Laakkonen L, Haiko J, Johansson T, Juuti K, Suomalainen M, Buchrieser C, Kalkkinen N, Korhonen TK. Human single-chain urokinase is activated by the omptins PgtE of Salmonella enterica and Pla of Yersinia pestis despite mutations of active site residues. Mol Microbiol 2013; 89:507-17. [PMID: 23763588 DOI: 10.1111/mmi.12293] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2013] [Indexed: 01/05/2023]
Abstract
Fibrinolysis is important in cell migration and tightly regulated by specific inhibitors and activators; of the latter, urokinase (uPA) associates with enhancement of cell migration. Active uPA is formed through cleavage of the single-chain uPA (scuPA). The Salmonella enterica strain 14028R cleaved human scuPA at the peptide bond Lys158-Ile159, the site cleaved also by the physiological activator human plasmin. The cleavage led to activation of scuPA, while no cleavage or activation were detected with the mutant strain 14028R lacking the omptin protease PgtE. Complementation and expression studies confirmed the role of PgtE in scuPA activation. Similar cleavage and activation of scuPA were detected with recombinant Escherichia coli expressing the omptin genes pla from Yersinia pestis, ompT and ompP from E. coli, sopA from Shigella flexneri, and leo from Legionella pneumophila. For these omptins the activation of scuPA is the only shared function so far detected. Only poor cleavage and activation of scuPA were seen with YcoA of Y. pestis and YcoB of Yersinia pseudotuberculosis that are considered to be proteolytically inactive omptin variants. Point mutations of active site residues in Pla and PgtE had different effects on the proteolysis of plasminogen and of scuPA, indicating versatility in omptin proteolysis.
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Affiliation(s)
- Hanna M Järvinen
- Division of General Microbiology, Department of Biosciences, University of Helsinki, P.O. Box 56, FI, 00014, Finland
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Brannon JR, Thomassin JL, Desloges I, Gruenheid S, Le Moual H. Role of uropathogenicEscherichia coliOmpT in the resistance against human cathelicidin LL-37. FEMS Microbiol Lett 2013; 345:64-71. [DOI: 10.1111/1574-6968.12185] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 05/22/2013] [Accepted: 05/24/2013] [Indexed: 11/30/2022] Open
Affiliation(s)
- John R. Brannon
- Department of Microbiology and Immunology; McGill University; Montreal; QC; Canada
| | - Jenny-Lee Thomassin
- Department of Microbiology and Immunology; McGill University; Montreal; QC; Canada
| | - Isabelle Desloges
- Department of Microbiology and Immunology; McGill University; Montreal; QC; Canada
| | - Samantha Gruenheid
- Department of Microbiology and Immunology; McGill University; Montreal; QC; Canada
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50
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Lawrenz MB, Pennington J, Miller VL. Acquisition of omptin reveals cryptic virulence function of autotransporter YapE in Yersinia pestis. Mol Microbiol 2013; 89:276-87. [PMID: 23701256 DOI: 10.1111/mmi.12273] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2013] [Indexed: 02/02/2023]
Abstract
Autotransporters, the largest family of secreted proteins in Gram-negative bacteria, perform a variety of functions, including adherence, cytotoxicity and immune evasion. In Yersinia pestis the autotransporter YapE has adhesive properties and contributes to disease in the mouse model of bubonic plague. Here, we demonstrate that omptin cleavage of Y. pestis YapE is required to mediate bacterial aggregation and adherence to eukaryotic cells. We demonstrate that omptin cleavage is specific for the Y. pestis and Y. pseudotuberculosis YapE orthologues but is not conserved in the Yersinia enterocolitica protein. We also show that cleavage of YapE occurs in Y. pestis but not in the enteric Yersinia species, and requires the omptin Pla (plasminogen activator protease), which is encoded on the Y. pestis-specific plasmid pPCP1. Together, these data show that post-translation modification of YapE appears to be specific to Y. pestis, was acquired along with the acquisition of pPCP1 during the divergence of Y. pestis from Y. pseudotuberculosis, and are the first evidence of a novel mechanism to regulate bacterial adherence.
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Affiliation(s)
- Matthew B Lawrenz
- Center for Predictive Medicine for Biodefense and Emerging Infectious Diseases, Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, KY, USA.
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