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Bavlovic J, Pavkova I, Balonova L, Benada O, Stulik J, Klimentova J. Intact O-antigen is critical structure for the exceptional tubular shape of outer membrane vesicles in Francisella tularensis. Microbiol Res 2023; 269:127300. [PMID: 36641863 DOI: 10.1016/j.micres.2023.127300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 12/19/2022] [Accepted: 01/06/2023] [Indexed: 01/13/2023]
Abstract
Francisella tularensis is a highly infectious Gram-negative coccobacillus which causes the disease tularemia. The potential for its misuse as a biological weapon has led disease control and prevention centers to classify this bacterium as a category A agent. Bacterial outer membrane vesicles (OMVs) are spherical particles 20-250 nm in size produced by all Gram-negative bacteria and constitute one of the major secretory pathways. Bacteria use them in interacting with both other bacterial cells and eukaryotic (host) cells. OMVs of Francisella contain number of its so far described virulence factors and immunomodulatory proteins. Their role in host-pathogen interactions can therefore be presumed, and the possibility exists also for their potential use in a subunit vaccine. Moreover, Francisella microbes produce both usual spherical and unusual tubular OMVs. Because OMVs emerge from the outermost surface of the bacterial cell, we focused on the secretion of OMVs in several mutant Francisella strains with disrupted surface structures (namely the O-antigen). O-antigen in Francisella is not only the structural component of LPS but also forms another important virulence factor: the O-antigen polysaccharide capsule. Mutant strain phenotypes were evaluated by growth curves, vesiculation rates, their sensitivity to the complement contained in serum, and proliferation inside murine bone marrow macrophages. Morphologies of both OMVs and the bacteria were visualized by electron microscopy. The O-antigen mutant strains were considerably attenuated in serum resistance and intracellular proliferation. All the strains showed lower ability to form the tubular OMVs. Some strains formed tubular protrusions from their outer membrane but their stability was weak. Some hypervesiculating strains were revealed that will serve as source of OMVs for further studies of their protective potential. Our results suggest the presence of LPS and the O-antigen capsule on the surface of Francisella to be critical not only for its virulence but also for the exceptional tubular shape of its OMVs.
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Affiliation(s)
- Jan Bavlovic
- University of Defense, Faculty of Military Health Sciences, Department of Molecular Pathology and Biology, Třebešská 1575, 500 01 Hradec Králové, Czech Republic
| | - Ivona Pavkova
- University of Defense, Faculty of Military Health Sciences, Department of Molecular Pathology and Biology, Třebešská 1575, 500 01 Hradec Králové, Czech Republic
| | - Lucie Balonova
- University of Defense, Faculty of Military Health Sciences, Department of Molecular Pathology and Biology, Třebešská 1575, 500 01 Hradec Králové, Czech Republic
| | - Oldrich Benada
- Czech Academy of Sciences, Institute of Microbiology, Krč, Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - Jiri Stulik
- University of Defense, Faculty of Military Health Sciences, Department of Molecular Pathology and Biology, Třebešská 1575, 500 01 Hradec Králové, Czech Republic
| | - Jana Klimentova
- University of Defense, Faculty of Military Health Sciences, Department of Molecular Pathology and Biology, Třebešská 1575, 500 01 Hradec Králové, Czech Republic.
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Tularemia Presenting Solely with Cervical Lymphadenopathy and Fever. Diagnostics (Basel) 2022; 12:diagnostics12082000. [PMID: 36010350 PMCID: PMC9407280 DOI: 10.3390/diagnostics12082000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/12/2022] [Accepted: 08/16/2022] [Indexed: 11/21/2022] Open
Abstract
A 52-year-old German female presented with cervical lymphadenopathy and fever. Despite the initial symptom-presentation leading to the consideration of sarcoidosis, lymphoma, tuberculosis, and toxoplasmosis, an extensive serologic and histo- and molecular pathologic workup eventually indicated a likely diagnosis of tularemia. This case brings to light that tularemia is a diagnostic challenge and requires high reliance on the epidemiological context thorough patient history, and an extensive interdisciplinary diagnostic workup.
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3
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Nagaratnam N, Martin-Garcia JM, Yang JH, Goode MR, Ketawala G, Craciunescu FM, Zook JD, Sonowal M, Williams D, Grant TD, Fromme R, Hansen DT, Fromme P. Structural and biophysical properties of FopA, a major outer membrane protein of Francisella tularensis. PLoS One 2022; 17:e0267370. [PMID: 35913965 PMCID: PMC9342783 DOI: 10.1371/journal.pone.0267370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 07/08/2022] [Indexed: 11/20/2022] Open
Abstract
Francisella tularensis is an extremely infectious pathogen and a category A bioterrorism agent. It causes the highly contagious zoonosis, Tularemia. Currently, FDA approved vaccines against tularemia are unavailable. F. tularensis outer membrane protein A (FopA) is a well-studied virulence determinant and protective antigen against tularemia. It is a major outer membrane protein (Omp) of F. tularensis. However, FopA-based therapeutic intervention is hindered due to lack of complete structural information for membrane localized mature FopA. In our study, we established recombinant expression, monodisperse purification, crystallization and X-ray diffraction (~6.5 Å) of membrane localized mature FopA. Further, we performed bioinformatics and biophysical experiments to unveil its structural organization in the outer membrane. FopA consists of 393 amino acids and has less than 40% sequence identity to known bacterial Omps. Using comprehensive sequence alignments and structure predictions together with existing partial structural information, we propose a two-domain organization for FopA. Circular dichroism spectroscopy and heat modifiability assay confirmed FopA has a β-barrel domain consistent with alphafold2’s prediction of an eight stranded β-barrel at the N-terminus. Small angle X-ray scattering (SAXS) and native-polyacrylamide gel electrophoresis revealed FopA purified in detergent micelles is predominantly dimeric. Molecular density derived from SAXS at 31 Å shows putative dimeric N-terminal β-barrels surrounded by detergent corona and connected to C-terminal domains via flexible linker. Disorder analysis predicts N- and C-terminal domains are interspersed by a long intrinsically disordered region and alphafold2 predicts this region to be largely unstructured. Taken together, we propose a dimeric, two-domain organization of FopA in the outer membrane: the N-terminal β-barrel is membrane embedded, provides dimerization interface and tethers to membrane extrinsic C-terminal domain via long flexible linker. Structure determination of membrane localized mature FopA is essential to understand its role in pathogenesis and develop anti-tularemia therapeutics. Our results pave the way towards it.
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Affiliation(s)
- Nirupa Nagaratnam
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Jose M. Martin-Garcia
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Jay-How Yang
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Matthew R. Goode
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Gihan Ketawala
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Felicia M. Craciunescu
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - James D. Zook
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Manashi Sonowal
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Dewight Williams
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- Eyring Materials Center, Arizona State University, Tempe, Arizona, United States of America
| | - Thomas D. Grant
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, New York, New York, United States of America
| | - Raimund Fromme
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Debra T. Hansen
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- Center for Innovations in Medicine, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Petra Fromme
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
- * E-mail:
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Schöbi N, Agyeman PKA, Duppenthaler A, Bartenstein A, Keller PM, Suter-Riniker F, Schmidt KM, Kopp MV, Aebi C. PEDIATRIC TULAREMIA– A CASE SERIES FROM A SINGLE CENTER IN SWITZERLAND. Open Forum Infect Dis 2022; 9:ofac292. [PMID: 35873298 PMCID: PMC9301579 DOI: 10.1093/ofid/ofac292] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/08/2022] [Indexed: 11/25/2022] Open
Abstract
Background The incidence of tularemia has recently increased throughout Europe. Pediatric tularemia typically presents with ulceroglandular or glandular disease and requires antimicrobial therapy not used in the empirical management of childhood acute lymphadenitis. We describe the clinical presentation and course in a case series comprising 20 patients. Methods This is a retrospective analysis of a single-center case series of microbiologically confirmed tularemia in patients <16 years of age diagnosed between 2010 and 2021. Results Nineteen patients (95%) presented with ulceroglandular (n = 14) or glandular disease (n = 5), respectively. A characteristic entry site lesion (eschar) was present in 14 (74%). Fever was present at illness onset in 15 patients (75%) and disappeared in all patients before targeted therapy was initiated. The diagnosis was confirmed by serology in 18 patients (90%). While immunochromatography was positive as early as on day 7, a microagglutination test titer 1:≥160 was found no earlier than on day 13. Sixteen patients (80%) were initially treated with an antimicrobial agent ineffective against F. tularensis. The median delay (range) from illness onset to initiation of targeted therapy was 12 (6–40) days. Surgical incision and drainage were ultimately performed in 12 patients (60%). Conclusions Pediatric tularemia in Switzerland usually presents with early, self-limiting fever and a characteristic entry site lesion with regional lymphadenopathy draining the scalp or legs. Particularly in association with a tick exposure history, this presentation may allow early first-line therapy with an agent specifically targeting F. tularensis, potentially obviating the need for surgical therapy.
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Affiliation(s)
- Nina Schöbi
- Division of Pediatric Infectious Disease, Department of Pediatrics, Bern University Hospital, Inselspital, University of Bern , Switzerland
| | - Philipp KA Agyeman
- Division of Pediatric Infectious Disease, Department of Pediatrics, Bern University Hospital, Inselspital, University of Bern , Switzerland
| | - Andrea Duppenthaler
- Division of Pediatric Infectious Disease, Department of Pediatrics, Bern University Hospital, Inselspital, University of Bern , Switzerland
| | - Andreas Bartenstein
- Department of Pediatric Surgery, Bern University Hospital, Inselspital, University of Bern , Switzerland
| | - Peter M Keller
- Institute for Infectious Diseases, University of Bern , Switzerland
| | | | - Kristina M Schmidt
- Spiez Laboratory, Federal Office for Civil Protection and Swiss National Reference Center for Francisella tularensis (NANT) , Spiez , Switzerland
| | - Matthias V Kopp
- Division of Pediatric Infectious Disease, Department of Pediatrics, Bern University Hospital, Inselspital, University of Bern , Switzerland
- 17 Center North (ARCN), Member of the German Lung Research Center (DZL) , 18 University of Luebeck , Germany
| | - Christoph Aebi
- Division of Pediatric Infectious Disease, Department of Pediatrics, Bern University Hospital, Inselspital, University of Bern , Switzerland
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Ma Z, Higgs M, Alqahtani M, Bakshi CS, Malik M. ThioredoxinA1 Controls the Oxidative Stress Response of Francisella tularensis Live Vaccine Strain (LVS). J Bacteriol 2022; 204:e0008222. [PMID: 35475633 PMCID: PMC9112935 DOI: 10.1128/jb.00082-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 04/01/2022] [Indexed: 11/20/2022] Open
Abstract
Francisella tularensis is an intracellular, Gram-negative bacterium known for causing a disease known as tularemia in the Northern Hemisphere. F. tularensis is classified as a category A select agent by the CDC based on its possible use as a bioterror agent. F. tularensis overcomes oxidative stress encountered during its growth in the environment or host macrophages by encoding antioxidant enzymes such as superoxide dismutases, catalase, and alkylhydroperoxy reductase. These antioxidant enzymes are regulated by the oxidative stress response regulator, OxyR. In addition to these antioxidant enzymes, F. tularensis also encodes two thioredoxins, TrxA1 (FTL_0611) and TrxA2 (FTL_1224); however, their role in the oxidative stress response of F. tularensis is not known. This study investigated the role of thioredoxins of F. tularensis in the oxidative stress response and intracellular survival. Our results demonstrate that TrxA1 but not TrxA2 plays a major role in the oxidative stress response of F. tularensis. Most importantly, this study elucidates a novel mechanism through which the TrxA1 of F. tularensis controls the oxidative stress response by regulating the expression of the master regulator, oxyR. Further, TrxA1 is required for the intramacrophage survival and growth of Francisella. Overall, this study describes a novel role of thioredoxin, TrxA1, in regulating the oxidative stress response of F. tularensis. IMPORTANCE The role of thioredoxins in the oxidative stress response of F. tularensis is not known. This study demonstrates that of the two thioredoxins, TrxA1 is vital to counter the oxidative stress in F. tularensis live vaccine strain (LVS). Furthermore, this study shows differences in the well-studied thioredoxins of Escherichia coli. First, the expression of TrxA1 of F. tularensis is independent of the oxidative stress response regulator, OxyR. Second and most importantly, TrxA1 regulates the expression of oxyR and, therefore, the OxyR-dependent oxidative stress response of F. tularensis. Overall, this study reports a novel regulatory role of TrxA1 of F. tularensis in the oxidative stress response.
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Affiliation(s)
- Zhuo Ma
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, New York, USA
| | - Matthew Higgs
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, New York, USA
| | - Maha Alqahtani
- Department of Pathology, Microbiology, and Immunology, New York Medical College, Valhalla, New York, USA
| | - Chandra Shekhar Bakshi
- Department of Pathology, Microbiology, and Immunology, New York Medical College, Valhalla, New York, USA
| | - Meenakshi Malik
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, New York, USA
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Ozanic M, Marecic V, Knezevic M, Kelava I, Stojková P, Lindgren L, Bröms JE, Sjöstedt A, Abu Kwaik Y, Santic M. The type IV pili component PilO is a virulence determinant of Francisella novicida. PLoS One 2022; 17:e0261938. [PMID: 35077486 PMCID: PMC8789160 DOI: 10.1371/journal.pone.0261938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 12/14/2021] [Indexed: 12/03/2022] Open
Abstract
Francisella tularensis is a highly pathogenic intracellular bacterium that causes the disease tularemia. While its ability to replicate within cells has been studied in much detail, the bacterium also encodes a less characterised type 4 pili (T4P) system. T4Ps are dynamic adhesive organelles identified as major virulence determinants in many human pathogens. In F. tularensis, the T4P is required for adherence to the host cell, as well as for protein secretion. Several components, including pilins, a pili peptidase, a secretin pore and two ATPases, are required to assemble a functional T4P, and these are encoded within distinct clusters on the Francisella chromosome. While some of these components have been functionally characterised, the role of PilO, if any, still is unknown. Here, we examined the role of PilO in the pathogenesis of F. novicida. Our results show that the PilO is essential for pilus assembly on the bacterial surface. In addition, PilO is important for adherence of F. novicida to human monocyte-derived macrophages, secretion of effector proteins and intracellular replication. Importantly, the pilO mutant is attenuated for virulence in BALB/c mice regardless of the route of infection. Following intratracheal and intradermal infection, the mutant caused no histopathology changes, and demonstrated impaired phagosomal escape and replication within lung liver as well as spleen. Thus, PilO is an essential virulence determinant of F. novicida.
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Affiliation(s)
- Mateja Ozanic
- Faculty of Medicine, Department of Microbiology and Parasitology, University of Rijeka, Rijeka, Croatia
| | - Valentina Marecic
- Faculty of Medicine, Department of Microbiology and Parasitology, University of Rijeka, Rijeka, Croatia
| | - Masa Knezevic
- Faculty of Medicine, Department of Microbiology and Parasitology, University of Rijeka, Rijeka, Croatia
| | - Ina Kelava
- Faculty of Medicine, Department of Microbiology and Parasitology, University of Rijeka, Rijeka, Croatia
| | - Pavla Stojková
- Department of Clinical Microbiology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Lena Lindgren
- Department of Clinical Microbiology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Jeanette E. Bröms
- Department of Clinical Microbiology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Anders Sjöstedt
- Department of Clinical Microbiology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology and Center for Predictive Medicine, College of Medicine, University of Louisville, Louisville, Kentucky, United States of America
| | - Marina Santic
- Faculty of Medicine, Department of Microbiology and Parasitology, University of Rijeka, Rijeka, Croatia
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Novel Transcriptional and Translational Biomarkers of Tularemia Vaccine Efficacy in a Mouse Inhalation Model: Proof of Concept. Microorganisms 2021; 10:microorganisms10010036. [PMID: 35056485 PMCID: PMC8778127 DOI: 10.3390/microorganisms10010036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/15/2021] [Accepted: 12/20/2021] [Indexed: 11/18/2022] Open
Abstract
Francisella tularensis subspecies tularensis (Ftt) is extremely virulent for humans when inhaled as a small particle aerosol (<5 µm). Inhalation of ≥20 viable bacteria is sufficient to initiate infection with a mortality rate ≥30%. Consequently, in the past, Ftt became a primary candidate for biological weapons development. To counter this threat, the USA developed a live vaccine strain (LVS), that showed efficacy in humans against inhalation of virulent Ftt. However, the breakthrough dose was fairly low, and protection waned with time. These weaknesses triggered extensive research for better vaccine candidates. Previously, we showed that deleting the clpB gene from virulent Ftt strain, SCHU S4, resulted in a mutant that was significantly less virulent than LVS for mice, yet better protected them from aerosol challenge with wild-type SCHU S4. To date, comprehensive searches for correlates of protection for SCHU S4 ΔclpB among molecules that are critical signatures of cell-mediated immunity, have yielded little reward. In this study we used transcriptomics analysis to expand the potential range of molecular correlates of protection induced by vaccination with SCHU S4 ΔclpB beyond the usual candidates. The results provide proof-of-concept that unusual host responses to vaccination can potentially serve as novel efficacy biomarkers for new tularemia vaccines.
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Pavkova I, Klimentova J, Bavlovic J, Horcickova L, Kubelkova K, Vlcak E, Raabova H, Filimonenko V, Ballek O, Stulik J. Francisella tularensis Outer Membrane Vesicles Participate in the Early Phase of Interaction With Macrophages. Front Microbiol 2021; 12:748706. [PMID: 34721352 PMCID: PMC8554293 DOI: 10.3389/fmicb.2021.748706] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/21/2021] [Indexed: 01/18/2023] Open
Abstract
Francisella tularensis is known to release unusually shaped tubular outer membrane vesicles (OMV) containing a number of previously identified virulence factors and immunomodulatory proteins. In this study, we present that OMV isolated from the F. tularensis subsp. holarctica strain FSC200 enter readily into primary bone marrow-derived macrophages (BMDM) and seem to reside in structures resembling late endosomes in the later intervals. The isolated OMV enter BMDM generally via macropinocytosis and clathrin-dependent endocytosis, with a minor role played by lipid raft-dependent endocytosis. OMVs proved to be non-toxic and had no negative impact on the viability of BMDM. Unlike the parent bacterium itself, isolated OMV induced massive and dose-dependent proinflammatory responses in BMDM. Using transmission electron microscopy, we also evaluated OMV release from the bacterial surface during several stages of the interaction of Francisella with BMDM. During adherence and the early phase of the uptake of bacteria, we observed numerous tubular OMV-like protrusions bulging from the bacteria in close proximity to the macrophage plasma membrane. This suggests a possible role of OMV in the entry of bacteria into host cells. On the contrary, the OMV release from the bacterial surface during its cytosolic phase was negligible. We propose that OMV play some role in the extracellular phase of the interaction of Francisella with the host and that they are involved in the entry mechanism of the bacteria into macrophages.
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Affiliation(s)
- Ivona Pavkova
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
| | - Jana Klimentova
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
| | - Jan Bavlovic
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
| | - Lenka Horcickova
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
| | - Klara Kubelkova
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
| | - Erik Vlcak
- Electron Microscopy Core Facility, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Helena Raabova
- Electron Microscopy Core Facility, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Vlada Filimonenko
- Electron Microscopy Core Facility, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia.,Department of Biology of the Cell Nucleus, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Ondrej Ballek
- Laboratory of Immunobiology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Jiri Stulik
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
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Hannah EE, Pandit SG, Hau D, DeMers HL, Robichaux K, Nualnoi T, Dissanayaka A, Arias-Umana J, Green HR, Thorkildson P, Pflughoeft KJ, Gates-Hollingsworth MA, Ozsurekci Y, AuCoin DP. Development of Immunoassays for Detection of Francisella tularensis Lipopolysaccharide in Tularemia Patient Samples. Pathogens 2021; 10:pathogens10080924. [PMID: 34451388 PMCID: PMC8401977 DOI: 10.3390/pathogens10080924] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/16/2021] [Accepted: 07/20/2021] [Indexed: 11/16/2022] Open
Abstract
Francisella tularensis is the causative agent of tularemia, a zoonotic bacterial infection that is often fatal if not diagnosed and treated promptly. Natural infection in humans is relatively rare, yet persistence in animal reservoirs, arthropod vectors, and water sources combined with a low level of clinical recognition make tularemia a serious potential threat to public health in endemic areas. F. tularensis has also garnered attention as a potential bioterror threat, as widespread dissemination could have devastating consequences on a population. A low infectious dose combined with a wide range of symptoms and a short incubation period makes timely diagnosis of tularemia difficult. Current diagnostic techniques include bacterial culture of patient samples, PCR and serological assays; however, these techniques are time consuming and require technical expertise that may not be available at the point of care. In the event of an outbreak or exposure a more efficient diagnostic platform is needed. The lipopolysaccharide (LPS) component of the bacterial outer leaflet has been identified previously by our group as a potential diagnostic target. For this study, a library of ten monoclonal antibodies specific to F. tularensis LPS were produced and confirmed to be reactive with LPS from type A and type B strains. Antibody pairs were tested in an antigen-capture enzyme-linked immunosorbent assay (ELISA) and lateral flow immunoassay format to select the most sensitive pairings. The antigen-capture ELISA was then used to detect and quantify LPS in serum samples from tularemia patients for the first time to determine the viability of this molecule as a diagnostic target. In parallel, prototype lateral flow immunoassays were developed, and reactivity was assessed, demonstrating the potential utility of this assay as a rapid point-of-care test for diagnosis of tularemia.
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Affiliation(s)
- Emily E. Hannah
- Department of Microbiology and Immunology, Reno School of Medicine, University of Nevada, Reno, NV 89509, USA; (E.E.H.); (S.G.P.); (D.H.); (H.L.D.); (K.R.); (T.N.); (A.D.); (J.A.-U.); (H.R.G.); (P.T.); (K.J.P.); (M.A.G.-H.)
| | - Sujata G. Pandit
- Department of Microbiology and Immunology, Reno School of Medicine, University of Nevada, Reno, NV 89509, USA; (E.E.H.); (S.G.P.); (D.H.); (H.L.D.); (K.R.); (T.N.); (A.D.); (J.A.-U.); (H.R.G.); (P.T.); (K.J.P.); (M.A.G.-H.)
| | - Derrick Hau
- Department of Microbiology and Immunology, Reno School of Medicine, University of Nevada, Reno, NV 89509, USA; (E.E.H.); (S.G.P.); (D.H.); (H.L.D.); (K.R.); (T.N.); (A.D.); (J.A.-U.); (H.R.G.); (P.T.); (K.J.P.); (M.A.G.-H.)
| | - Haley L. DeMers
- Department of Microbiology and Immunology, Reno School of Medicine, University of Nevada, Reno, NV 89509, USA; (E.E.H.); (S.G.P.); (D.H.); (H.L.D.); (K.R.); (T.N.); (A.D.); (J.A.-U.); (H.R.G.); (P.T.); (K.J.P.); (M.A.G.-H.)
| | - Kayleigh Robichaux
- Department of Microbiology and Immunology, Reno School of Medicine, University of Nevada, Reno, NV 89509, USA; (E.E.H.); (S.G.P.); (D.H.); (H.L.D.); (K.R.); (T.N.); (A.D.); (J.A.-U.); (H.R.G.); (P.T.); (K.J.P.); (M.A.G.-H.)
| | - Teerapat Nualnoi
- Department of Microbiology and Immunology, Reno School of Medicine, University of Nevada, Reno, NV 89509, USA; (E.E.H.); (S.G.P.); (D.H.); (H.L.D.); (K.R.); (T.N.); (A.D.); (J.A.-U.); (H.R.G.); (P.T.); (K.J.P.); (M.A.G.-H.)
| | - Anjana Dissanayaka
- Department of Microbiology and Immunology, Reno School of Medicine, University of Nevada, Reno, NV 89509, USA; (E.E.H.); (S.G.P.); (D.H.); (H.L.D.); (K.R.); (T.N.); (A.D.); (J.A.-U.); (H.R.G.); (P.T.); (K.J.P.); (M.A.G.-H.)
| | - Jose Arias-Umana
- Department of Microbiology and Immunology, Reno School of Medicine, University of Nevada, Reno, NV 89509, USA; (E.E.H.); (S.G.P.); (D.H.); (H.L.D.); (K.R.); (T.N.); (A.D.); (J.A.-U.); (H.R.G.); (P.T.); (K.J.P.); (M.A.G.-H.)
| | - Heather R. Green
- Department of Microbiology and Immunology, Reno School of Medicine, University of Nevada, Reno, NV 89509, USA; (E.E.H.); (S.G.P.); (D.H.); (H.L.D.); (K.R.); (T.N.); (A.D.); (J.A.-U.); (H.R.G.); (P.T.); (K.J.P.); (M.A.G.-H.)
| | - Peter Thorkildson
- Department of Microbiology and Immunology, Reno School of Medicine, University of Nevada, Reno, NV 89509, USA; (E.E.H.); (S.G.P.); (D.H.); (H.L.D.); (K.R.); (T.N.); (A.D.); (J.A.-U.); (H.R.G.); (P.T.); (K.J.P.); (M.A.G.-H.)
| | - Kathryn J. Pflughoeft
- Department of Microbiology and Immunology, Reno School of Medicine, University of Nevada, Reno, NV 89509, USA; (E.E.H.); (S.G.P.); (D.H.); (H.L.D.); (K.R.); (T.N.); (A.D.); (J.A.-U.); (H.R.G.); (P.T.); (K.J.P.); (M.A.G.-H.)
| | - Marcellene A. Gates-Hollingsworth
- Department of Microbiology and Immunology, Reno School of Medicine, University of Nevada, Reno, NV 89509, USA; (E.E.H.); (S.G.P.); (D.H.); (H.L.D.); (K.R.); (T.N.); (A.D.); (J.A.-U.); (H.R.G.); (P.T.); (K.J.P.); (M.A.G.-H.)
| | | | - David P. AuCoin
- Department of Microbiology and Immunology, Reno School of Medicine, University of Nevada, Reno, NV 89509, USA; (E.E.H.); (S.G.P.); (D.H.); (H.L.D.); (K.R.); (T.N.); (A.D.); (J.A.-U.); (H.R.G.); (P.T.); (K.J.P.); (M.A.G.-H.)
- Correspondence:
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Gaur R, Verma DK, Alam SI, Kamboj DV. Identification of MHC Class I bound peptides of Francisella tularensis Live Vaccine Strain using mass spectrometry. Eur J Pharm Sci 2021; 158:105651. [DOI: 10.1016/j.ejps.2020.105651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/30/2020] [Accepted: 11/18/2020] [Indexed: 11/29/2022]
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Klimentova J, Rehulka P, Pavkova I, Kubelkova K, Bavlovic J, Stulik J. Cross-Species Proteomic Comparison of Outer Membrane Vesicles and Membranes of Francisella tularensis subsp. tularensis versus subsp. holarctica. J Proteome Res 2021; 20:1716-1732. [PMID: 33543941 DOI: 10.1021/acs.jproteome.0c00917] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Release of outer membrane vesicles (OMV) is an important phenomenon in Gram-negative bacteria playing multiple roles in their lifestyle, including in relation to virulence and host-pathogen interaction. Francisella tularensis, unlike other bacteria, releases unusually shaped, tubular OMV. We present a proteomic comparison of OMV and membrane fractions from two F. tularensis strains: moderately virulent subsp. holarctica strain FSC200 and highly virulent subsp. tularensis strain SchuS4. Proteomic comparison studies routinely evaluate samples from the same proteome, but sometimes we must compare samples from closely related organisms. This raises quantification issues. We propose a novel approach to cross-species proteomic comparison based on an intersection protein database from the individual single-species databases. This is less prone to quantification errors arising from differences in the sequences. Consecutively comparing subproteomes of OMV and membranes of the two strains allows distinguishing differences in relative protein amounts caused by global expression changes from those caused by preferential protein packing to OMV or membranes. Among the proteins most differently packed into OMV between the two strains, we detected proteins involved in biosynthesis and metabolism of bacterial envelope components like O-antigen, lipid A, phospholipids, and fatty acids, as well as some major structural outer membrane proteins. The data are available via ProteomeXchange with identifier PXD022406.
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Affiliation(s)
- Jana Klimentova
- Faculty of Military Health Sciences, Department of Molecular Pathology and Biology, University of Defence, Hradec Kralove 500 01, Czech Republic
| | - Pavel Rehulka
- Faculty of Military Health Sciences, Department of Molecular Pathology and Biology, University of Defence, Hradec Kralove 500 01, Czech Republic
| | - Ivona Pavkova
- Faculty of Military Health Sciences, Department of Molecular Pathology and Biology, University of Defence, Hradec Kralove 500 01, Czech Republic
| | - Klara Kubelkova
- Faculty of Military Health Sciences, Department of Molecular Pathology and Biology, University of Defence, Hradec Kralove 500 01, Czech Republic
| | - Jan Bavlovic
- Faculty of Military Health Sciences, Department of Molecular Pathology and Biology, University of Defence, Hradec Kralove 500 01, Czech Republic
| | - Jiri Stulik
- Faculty of Military Health Sciences, Department of Molecular Pathology and Biology, University of Defence, Hradec Kralove 500 01, Czech Republic
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Acanthamoeba - pathogen and vector of highly pathogenic bacteria strains to healthy and immunocompromised individuals. Cent Eur J Immunol 2021; 45:228-232. [PMID: 33456336 PMCID: PMC7792437 DOI: 10.5114/ceji.2020.97667] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 06/28/2019] [Indexed: 11/17/2022] Open
Abstract
Acanthamoeba is a free-living protist pathogen, which is present in every place on Earth. 50 to 100 percent of the adult population has serum antibodies, specific for Acanthamoeba antigens. Acanthamoeba is an etiological agent of keratitis and encephalitis diagnosed in human. Acanthamoeba keratitis occurs in healthy persons and may lead to visual impairment and blindness, because corneal infection with this parasite fails to induce cell-mediated immune response due to the absence of resident antigen-presenting cells in the cornea. Systemic immunization with Acanthamoeba antigens induces Th1 cell-mediated immunity and serum IgG antibody, but do not prevent the development of keratitis. Immunization via mucosal surfaces stimulates IgA antibodies in tears and protects against the development of keratitis. Amoebae feed mainly on bacteria, fungi, and algae. By transferring intracellular bacteria, amoeba contributes to the spread of diseases dangerous to humans. Some microorganisms have evolved to become resistant to protist, since they are not internalized or able to survive, grow, and exit free-living protists after internalization. In many cases, the bacteria inside living amoebae survive longer, and multiply better, showing higher virulence. There is a hypothesis, which assumes that Acanthamoeba and symbiontic bacteria survive and multiply better in moist soil, rich in nitrogen compounds, particularly in the vicinity of the root systems of Alnus glutinosa, infected with nitrogen-fixing bacteria Frankia alni. Impact of soil environment created by nitrogen-fixing bacterium Frankia alni on specific relations between protists Acanthamoeba and highly pathogenic bacteria strains in Alnus glutinosa habitats in Poland continue to be established.
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The Sensor Kinase QseC Regulates the Unlinked PmrA Response Regulator and Downstream Gene Expression in Francisella. J Bacteriol 2020; 202:JB.00321-20. [PMID: 32839173 DOI: 10.1128/jb.00321-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/13/2020] [Indexed: 12/22/2022] Open
Abstract
The facultative intracellular bacterial pathogen Francisella tularensis is the causative agent of tularemia in humans and animals. Gram-negative bacteria utilize two-component regulatory systems (TCS) to sense and respond to their changing environment. No classical, tandemly arranged sensor kinase and response regulator TCS genes exist in the human virulent Francisella tularensis subsp. tularensis, but orphaned members are present. PmrA is an orphan response regulator responsible for intramacrophage growth and virulence; however, the regulation of PmrA activity is not understood. We and others have shown that PmrA represses the expression of priM, described to encode an antivirulence determinant. By screening a mutant library for increased priM promoter activity, we identified the sensor kinase homolog QseC as an upstream regulator of priM expression, and this regulation is in part dependent upon the aspartate phosphorylation site of PmrA (D51). Several examined environmental signals, including epinephrine, which is reported to activate QseC in other bacteria, do not affect priM expression in a manner dependent on PmrA. Intramacrophage survival assays also question the finding that PriM is an antivirulence factor. Thus, these data suggest that the PmrA-regulated gene priM is modulated by the QseC-PmrA (QseB) TCS in Francisella IMPORTANCE The disease tularemia is caused by the highly infectious Gram-negative pathogen Francisella tularensis This bacterium encodes few regulatory factors (e.g., two-component systems [TCS]). PmrA, required for intramacrophage survival and virulence in the mouse model, is encoded by an orphan TCS response regulator gene. It is unclear how PmrA is responsive to environmental signals to regulate loci, including the PmrA-repressed gene priM We identify an orphan sensor kinase (QseC) that is required for priM repression and further explore both environmental signals that might regulate the QseC-PmrA TCS and the function of PriM.
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Parashar K, Carpino N. A role for the Sts phosphatases in negatively regulating IFNγ-mediated production of nitric oxide in monocytes. IMMUNITY INFLAMMATION AND DISEASE 2020; 8:523-533. [PMID: 32841534 PMCID: PMC7654413 DOI: 10.1002/iid3.336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 07/01/2020] [Accepted: 07/20/2020] [Indexed: 12/17/2022]
Abstract
Introduction The atypical Sts phosphatases negatively regulate signaling pathways in diverse immune cell types, with two of their molecular targets being the related kinases Syk and Zap‐70. Mice lacking Sts expression (Sts−/−) are resistant to infection by the live vaccine strain (LVS) of Francisella tularensis. Although the mechanisms underlying the enhanced resistance of Sts−/− mice have not been definitively established, Sts−/− bone marrow‐derived monocytes (BMMs) demonstrate greater clearance of intracellular LVS following ex vivo infection, relative to wild type cells. To determine how the Sts proteins regulate monocyte bactericidal properties, we analyzed responses of infected cells. Methods Monocyte bacterial clearance was assayed using ex vivo coculture infections followed by colony‐forming unit analysis of intracellular bacteria. Levels of gene expression were quantified by quantitative reverse‐transcription polymerase chain reaction, levels of Nos2 protein levels were quantified by Western blot analysis, and levels of nitric oxide (NO) were quantified directly using the Griess reagent. We characterized monocyte cytokine production via enzyme‐linked immunosorbent assay. Results We demonstrate that Sts−/− monocyte cultures produce elevated levels of interferon‐γ (IFNγ) after infection, relative to wild type cultures. Sts−/− monocytes also demonstrate heightened responsiveness to IFNγ. Specifically, Sts−/− monocytes produce elevated levels of antimicrobial NO following IFNγ stimulation, and this NO plays an important role in LVS restriction. Additional IFNγ‐stimulated genes, including Ip10 and members of the Gbp gene family, also display heightened upregulation in Sts−/− cells. Both Sts‐1 and Sts‐2 contribute to the regulation of NO production, as evidenced by the responses of monocytes lacking each phosphatase individually. Finally, we demonstrate that the elevated production of IFNγ‐induced NO in Sts−/− monocytes is abrogated following chemical inhibition of Syk kinase. Conclusion Our results indicate a novel role for the Sts enzymes in regulating monocyte antibacterial responses downstream of IFNγ.
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Affiliation(s)
- Kaustubh Parashar
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York
| | - Nicholas Carpino
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York
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Carruthers J, Lythe G, López-García M, Gillard J, Laws TR, Lukaszewski R, Molina-París C. Stochastic dynamics of Francisella tularensis infection and replication. PLoS Comput Biol 2020; 16:e1007752. [PMID: 32479491 PMCID: PMC7304631 DOI: 10.1371/journal.pcbi.1007752] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 06/19/2020] [Accepted: 02/27/2020] [Indexed: 12/12/2022] Open
Abstract
We study the pathogenesis of Francisella tularensis infection with an experimental mouse model, agent-based computation and mathematical analysis. Following inhalational exposure to Francisella tularensis SCHU S4, a small initial number of bacteria enter lung host cells and proliferate inside them, eventually destroying the host cell and releasing numerous copies that infect other cells. Our analysis of disease progression is based on a stochastic model of a population of infectious agents inside one host cell, extending the birth-and-death process by the occurrence of catastrophes: cell rupture events that affect all bacteria in a cell simultaneously. Closed expressions are obtained for the survival function of an infected cell, the number of bacteria released as a function of time after infection, and the total bacterial load. We compare our mathematical analysis with the results of agent-based computation and, making use of approximate Bayesian statistical inference, with experimental measurements carried out after murine aerosol infection with the virulent SCHU S4 strain of the bacterium Francisella tularensis, that infects alveolar macrophages. The posterior distribution of the rate of replication of intracellular bacteria is consistent with the estimate that the time between rounds of bacterial division is less than 6 hours in vivo. Infecting a host cell is required for the replication of many types of bacteria and viruses. In some cases, infected cells release new infectious agents continuously over their lifetime. In others, such as the Francisella tularensis bacterium studied here, they are released in a single burst that coincides with the cell’s death. We show how a stochastic model, the birth-and-death process with catastrophe, can be used to characterise infection in a single cell, thereby allowing us to account for burst events and quantify the kinetics of pathogenesis in the lung, the initial site of infection, as well as in other organs that the infection spreads to. We learn about the parameters of the mathematical model of Francisella tularensis infection making use of the experimental measurements of bacterial loads, together with approximate Bayesian statistical inference methods. The most important parameter describing the pathogenesis is the rate of replication of intracellular bacteria.
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Affiliation(s)
- Jonathan Carruthers
- Department of Applied Mathematics, University of Leeds, Leeds, United Kingdom
| | - Grant Lythe
- Department of Applied Mathematics, University of Leeds, Leeds, United Kingdom
| | - Martín López-García
- Department of Applied Mathematics, University of Leeds, Leeds, United Kingdom
| | - Joseph Gillard
- CBR Division, Defence Science and Technology Laboratory, Salisbury, United Kingdom
| | - Thomas R. Laws
- CBR Division, Defence Science and Technology Laboratory, Salisbury, United Kingdom
| | - Roman Lukaszewski
- CBR Division, Defence Science and Technology Laboratory, Salisbury, United Kingdom
| | - Carmen Molina-París
- Department of Applied Mathematics, University of Leeds, Leeds, United Kingdom
- * E-mail:
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Mihelčić M, Marečić V, Ožanič M, Kelava I, Knežević M, Šantić M. Epidemiologic and Epizootic Data of Tularemia in the Past and in the Recent History in Croatia. Microorganisms 2020; 8:microorganisms8050721. [PMID: 32408663 PMCID: PMC7284554 DOI: 10.3390/microorganisms8050721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/08/2020] [Accepted: 05/09/2020] [Indexed: 11/20/2022] Open
Abstract
Tularemia is a zoonotic disease caused by Francisella tularensis. A large number of recent studies have provided an update on the disease characteristics and the distribution across Europe. In Croatia, most of the clinical cases, as well as the reports of the disease in animals, date from the 20th century. In that period, epidemic and epizootic research had given detailed information about endemic regions and their characteristics, including suspected animal hosts and vectors. The region along the middle course of the Sava River, called Middle Posavina, is described as an endemic region, i.e., a “natural focus” of tularemia, in Croatia. In the 21st century, cases of human tularemia are being reported sporadically, with ulceloglandular, oropharyngeal and typhoid forms of disease. A majority of the described cases are linked with the consumption of contaminated food or water. The disease outbreaks still occur in areas along the course of the river Sava and in northwest Croatia. In this review article, we have summarized epidemiologic and epizootic data of tularemia in the past and in recent Croatian history.
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Buse HY, Morris BJ, Rice EW. Early detection of viable Francisella tularensis in environmental matrices by culture-based PCR. BMC Microbiol 2020; 20:66. [PMID: 32213160 PMCID: PMC7093956 DOI: 10.1186/s12866-020-01748-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 03/06/2020] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Francisella tularensis is a fastidious, Gram-negative coccobacillus and is the causative agent of tularemia. To assess viability yet overcome lengthy incubation periods, a culture-based PCR method was used to detect early growth of the lowest possible number of F. tularensis cells. This method utilized a previously developed enhanced F. tularensis growth medium and is based on the change in PCR cycle threshold at the start and end of each incubation. RESULTS To test method robustness, a virulent Type A1 (Schu4) and B (IN99) strain and the avirulent Live Vaccine Strain (LVS) were incubated with inactivated target cells, humic acid, drinking and well water, and test dust at targeted starting concentrations of 1, 10, and 100 CFU mL- 1 (low, mid, and high, respectively). After 48 h, LVS growth was detected at all targeted concentrations in the presence of 106 inactivated LVS cells; while Schu4 and IN99 growth was detected in the presence of 104 Schu4 or IN99 inactivated cells at the mid and high targets. Early detection of F. tularensis growth was strain and concentration dependent in the presence of fast-growing well water and test dust organisms. In contrast, growth was detected at each targeted concentration by 24 h in humic acid and drinking water for all strains. CONCLUSIONS Results indicated that the culture-based PCR assay is quick, sensitive, and specific while still utilizing growth as a measure of pathogen viability. This method can circumvent lengthy incubations required for Francisella identification, especially when swift answers are needed during epidemiological investigations, remediation efforts, and decontamination verification.
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Affiliation(s)
- Helen Y Buse
- US EPA, Office of Research and Development, Center for Environmental Solutions & Emergency Response, 26 W Martin Luther King Drive NG-16, Cincinnati, OH, 45268, USA.
| | - Brian J Morris
- Pegasus Technical Services, Inc c/o US EPA, Cincinnati, OH, USA
| | - Eugene W Rice
- US EPA, Office of Research and Development, Center for Environmental Solutions & Emergency Response, 26 W Martin Luther King Drive NG-16, Cincinnati, OH, 45268, USA
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Marakasova E, Ii A, Nelson KT, van Hoek ML. Proteome Wide Profiling of N-ε-Lysine Acetylation Reveals a Novel Mechanism of Regulation of the Chitinase Activity in Francisella novicida. J Proteome Res 2020; 19:1409-1422. [PMID: 32056440 DOI: 10.1021/acs.jproteome.9b00512] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Francisella tularensis is a Gram-negative bacterium that causes the zoonotic disease tularemia. The historical development of tularemia as a biological weapon has led to it being characterized by the CDC as a category A biothreat agent. Neither posttranslational modification (PTM) of proteins, in particular lysine acetylation, in Francisella nor its subsequent regulation of the protein activity has been well studied. In this work, we analyze N-ε-lysine acetylation of the F. tularensis ssp. novicida proteome by mass spectrometry for the first time. To create a comprehensive acetylation profile, we enriched protein acetylation using two approaches: (1) the addition of glucose or acetate into the culture medium and (2) direct chemical acetylation of N-ε-lysines with acetyl phosphate. We discovered 280 acetylated proteins with 1178 acetylation sites in the F. tularensis ssp. novicida strain U112. Lysine acetylation is an important PTM that regulates multiple cellular processes in bacteria, including metabolism, transcription, translation, stress response, and protein folding. We discovered that Francisella chitinases A and B are acetylated naturally and when chemically induced by acetyl phosphate. Moreover, chemical overacetylation of chitinases results in silencing of the enzymatic activity. Our findings suggest a novel mechanism of posttranslational regulation of the chitinase activity and that acetylation may play a role in Francisella's regulation of the protein activity.
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Affiliation(s)
- Ekaterina Marakasova
- School of Systems Biology, George Mason University, 10900 University Blvd, Manassas, Virginia 20110, United States
| | - Alexandra Ii
- School of Systems Biology, George Mason University, 10900 University Blvd, Manassas, Virginia 20110, United States
| | - Kristina T Nelson
- Chemical and Proteomic Mass Spectrometry Core Facility, Virginia Commonwealth University, 1001 W. Main Street, Richmond, Virginia 23284, United States
| | - Monique L van Hoek
- School of Systems Biology, George Mason University, 10900 University Blvd, Manassas, Virginia 20110, United States
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Hemati M, Khalili M, Rohani M, Sadeghi B, Esmaeili S, Ghasemi A, Mahmoudi A, Gyuranecz M, Mostafavi E. A serological and molecular study on Francisella tularensis in rodents from Hamadan province, Western Iran. Comp Immunol Microbiol Infect Dis 2019; 68:101379. [PMID: 31733511 DOI: 10.1016/j.cimid.2019.101379] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 10/27/2019] [Accepted: 10/29/2019] [Indexed: 01/11/2023]
Abstract
INTRODUCTION AND PURPOSE Tularemia is a zoonotic disease, the most important hosts of which are rodents. Endemic regions and reservoirs of F. tularensis are not well-researched areas in Iran. The present study aimed to study F. tularensis infection in the rodent populations of western Iran. MATERIALS AND METHODS Samples were collected in different areas of Kabudar Ahang County in Hamadan province (west of Iran) from 2014 to 2017. Tularemia serological and molecular tests were conducted using the tube agglutination test and Real-time PCR method tracking the ISFtu2 gene. Positive serum samples were evaluated for cross-reactivity with brucellosis. RESULTS A total of 433 rodents, collected from 33 localities, were included in the study. The most abundant species belonged to the Persian jird (Meriones persicus; 75.5%), and Libyan jird (Meriones libycus; 10.1%). Among the studied samples, three (0.74 %) were seropositive and five (1.15%) were PCR positive. Seropositive samples were two M. persicus and one M. libycus, and PCR positive rodents were four M. persicus and one M. vinogradovi. Tularemia seropositive samples showed no cross-reactivity with brucellosis. CONCLUSION Given the presence of infection in rodents with tularemia agent in the studied area, it is crucial to elucidate the risks of rodent exposure to tularemia for physicians, health personnel and the general population.
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Affiliation(s)
- Majid Hemati
- Department of Pathobiology, Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Mohammad Khalili
- Department of Pathobiology, Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Mahdi Rohani
- National Reference Laboratory for Plague, Tularemia and Q Fever, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Kabudar Ahang, Hamadan, Iran; Department of Microbiology, Pasteur Institute of Iran, Tehran, Iran
| | - Balal Sadeghi
- Food Hygiene and Public Health Department, Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Saber Esmaeili
- National Reference Laboratory for Plague, Tularemia and Q Fever, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Kabudar Ahang, Hamadan, Iran; Department of Epidemiology and Biostatistics, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Tehran, Iran
| | - Ahmad Ghasemi
- National Reference Laboratory for Plague, Tularemia and Q Fever, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Kabudar Ahang, Hamadan, Iran; Department of Epidemiology and Biostatistics, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Tehran, Iran
| | - Ahmad Mahmoudi
- National Reference Laboratory for Plague, Tularemia and Q Fever, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Kabudar Ahang, Hamadan, Iran; Department of Epidemiology and Biostatistics, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Tehran, Iran
| | - Miklós Gyuranecz
- Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary; Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, Budapest, Hungary
| | - Ehsan Mostafavi
- National Reference Laboratory for Plague, Tularemia and Q Fever, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Kabudar Ahang, Hamadan, Iran; Department of Epidemiology and Biostatistics, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Tehran, Iran.
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Klimentova J, Pavkova I, Horcickova L, Bavlovic J, Kofronova O, Benada O, Stulik J. Francisella tularensis subsp. holarctica Releases Differentially Loaded Outer Membrane Vesicles Under Various Stress Conditions. Front Microbiol 2019; 10:2304. [PMID: 31649645 PMCID: PMC6795709 DOI: 10.3389/fmicb.2019.02304] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 09/20/2019] [Indexed: 11/16/2022] Open
Abstract
Francisella tularensis is a Gram-negative, facultative intracellular bacterium, causing a severe disease called tularemia. It secretes unusually shaped nanotubular outer membrane vesicles (OMV) loaded with a number of virulence factors and immunoreactive proteins. In the present study, the vesicles were purified from a clinical isolate of subsp. holarctica strain FSC200. We here provide a comprehensive proteomic characterization of OMV using a novel approach in which a comparison of OMV and membrane fraction is performed in order to find proteins selectively enriched in OMV vs. membrane. Only these proteins were further considered to be really involved in the OMV function and/or their exceptional structure. OMV were also isolated from bacteria cultured under various cultivation conditions simulating the diverse environments of F. tularensis life cycle. These included conditions mimicking the milieu inside the mammalian host during inflammation: oxidative stress, low pH, and high temperature (42°C); and in contrast, low temperature (25°C). We observed several-fold increase in vesiculation rate and significant protein cargo changes for high temperature and low pH. Further proteomic characterization of stress-derived OMV gave us an insight how the bacterium responds to the hostile environment of a mammalian host through the release of differentially loaded OMV. Among the proteins preferentially and selectively packed into OMV during stressful cultivations, the previously described virulence factors connected to the unique intracellular trafficking of Francisella were detected. Considerable changes were also observed in a number of proteins involved in the biosynthesis and metabolism of the bacterial envelope components like O-antigen, lipid A, phospholipids, and fatty acids. Data are available via ProteomeXchange with identifier PXD013074.
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Affiliation(s)
- Jana Klimentova
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defense, Hradec Kralove, Czechia
| | - Ivona Pavkova
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defense, Hradec Kralove, Czechia
| | - Lenka Horcickova
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defense, Hradec Kralove, Czechia
| | - Jan Bavlovic
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defense, Hradec Kralove, Czechia
| | - Olga Kofronova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
| | - Oldrich Benada
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia.,Faculty of Science, Jan Evangelista Purkyně University, Ústí nad Labem, Czechia
| | - Jiri Stulik
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defense, Hradec Kralove, Czechia
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21
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Ali AM, Noor ul Amin M, Arif S. First case report of post-operative infection due to Francisella tularensis after cardiac surgery. Access Microbiol 2019; 1:e000035. [PMID: 32974547 PMCID: PMC7470410 DOI: 10.1099/acmi.0.000035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 05/31/2019] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Francisella tularensis is a rare zoonotic bacterium that spreads sporadically by various routes, including infected arthropod bites, ingestion of contaminated water and inhalation of contaminated dust. However, its occurrence in postoperative chest infection has never been reported. Pathogen isolation, serology and molecular detection methods are commonly used for the diagnosis of tularaemia. CASE PRESENTATION We present the first case report of the isolation of F. tularensis from a patient with a chest infection (a boy in his teens) following cardiac surgery for closure of a ventral septal defect. It was isolated on blood and chocolate agar on the third day after the subculture of drain fluid collected in a blood culture bottle incubated in Bact T/Alert 3-D (bioMerieux, France). The organism was identified as F. tularensis by Vitek GN ID Cards (Vitek 2 Compact, bioMerieux, France). The patient made a smooth recovery with antibiotic therapy. CONCLUSION F. tularensis can cause post-operative infection, especially in patients with a rural background.
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Affiliation(s)
- Arif Maqsood Ali
- Department of Pathology and Blood Bank, Rawalpindi Institute of Cardiology, Rawalpindi, Punjab, Pakistan
| | - Muhammad Noor ul Amin
- Department of Pathology and Blood Bank, Rawalpindi Institute of Cardiology, Rawalpindi, Punjab, Pakistan
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22
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Muhammad J, Rabbani M, Shabbir MZ, Muhammad K, Ghori MT, Chaudhry HR, Ul Hassnain Z, Jamil T, Abbas T, Chaudhry MH, Haisem-ur-Rasool M, Ali MA, Nisar M, Kirimanjeswara GS, Jayarao BM. Cross Sectional Study and Risk Factors Analysis of Francisella tularensis in Soil Samples in Punjab Province of Pakistan. Front Cell Infect Microbiol 2019; 9:89. [PMID: 31024860 PMCID: PMC6460113 DOI: 10.3389/fcimb.2019.00089] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 03/12/2019] [Indexed: 12/16/2022] Open
Abstract
Tularemia is an endemic zoonotic disease in many parts of the world including Asia. A cross-sectional study was conducted to determine genome-based prevalence of Francisella tularensis (Ft) in soil, assess an association between its occurrence in soil and likely predictors i.e., macro and micro-nutrients and several categorical variables, and determine seroconversion in small and large ruminants. The study included a total of 2,280 soil samples representing 456 villages in eight districts of the Punjab Province of Pakistan followed by an analysis of serum antibodies in 707 ruminants. The genome of Ft was detected in 3.25% (n = 74, 95% CI: 2.60-4.06) of soil samples. Soluble salts (OR: 1.276, 95% CI: 1.043-1.562, p = 0.015), Ni (OR: 2.910, 95%CI: 0.795-10.644, p = 0.106), Mn (OR:0.733, 95% CI:0.565-0.951, p = 0.019), Zn (OR: 4.922, 95% CI:0.929-26.064, p = 0.061) and nutrients clustered together as PC-1 (OR: 4.76, 95% CI: 2.37-9.54, p = 0.000) and PC-3 (OR: 0.357, 95% CI: 0.640, p = 0.001) were found to have a positive association for the presence of Ft in soil. The odds of occurrence of Ft DNA in soil were higher at locations close to a water source, including canals, streams or drains, [χ2 = 6.7, OR = 1.19, 95% CI:1.05-3.09, p = 0.004] as well as places where animals were present [χ2 = 4.09, OR = 2.06, 95% CI: 1.05-4.05, p = 0.02]. The seroconversion was detected in 6.22% (n = 44, 95% CI: 4.67-8.25) of domestic animals. An occurrence of Ft over a wide geographical region indicates its expansion to enzootic range, and demonstrates the need for further investigation among potential disease reservoirs and at-risk populations, such as farmers and veterinarians.
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Affiliation(s)
- Javed Muhammad
- University of Veterinary and Animal Sciences, Lahore, Pakistan
- University of Swabi, Swabi, Pakistan
| | - Masood Rabbani
- University of Veterinary and Animal Sciences, Lahore, Pakistan
| | | | - Khushi Muhammad
- University of Veterinary and Animal Sciences, Lahore, Pakistan
| | | | | | - Zia Ul Hassnain
- University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Tariq Jamil
- University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Tariq Abbas
- Department of Epidemiology and Public Health, Cholistan University of Veterinary and Animal Sciences, Bahawalpur, Pakistan
| | | | | | | | - Muhammad Nisar
- Department of Epidemiology and Public Health, Cholistan University of Veterinary and Animal Sciences, Bahawalpur, Pakistan
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Zhou W, Yin Y, Smith E, Chou J, Shumate J, Scampavia L, Spicer TP, Carpino N, French JB. Discovery and Characterization of Two Classes of Selective Inhibitors of the Suppressor of the TCR Signaling Family of Proteins. ACS Infect Dis 2019; 5:250-259. [PMID: 30485744 DOI: 10.1021/acsinfecdis.8b00238] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The suppressor of T-cell receptor signaling (Sts) proteins, Sts-1, has recently emerged as a potential immunostimulatory target for drug development. Genetic inactivation of the Sts proteins dramatically increases host survival of systemic infection and leads to improved pathogen clearance. The protein tyrosine phosphatase (PTP) activity of these proteins arises from a C-terminal 2-histidine phosphatase (HP) domain. To identify new inhibitors of the HP activity of Sts-1, we miniaturized a phosphatase assay to a 1536-well format and conducted a 20 580 compound screen. Among the hits were two classes of structurally related compounds, tetracycline variants and sulfonated azo dyes. These hits had low micromolar to nanomolar IC50 values. Orthogonal screening confirmed the validity of these inhibitors and demonstrated that both act competitively on Sts-1 phosphatase activity. When tested on other PTPs, PTP1B and SHP1, it was found that the tetracycline PTP1B, SHP1, the tetracycline variant (doxycycline), and the sulfonated azo dye (Congo red) are selective inhibitors of Sts-1HP, with selectivity indices ranging from 19 to as high as 200. The planar polyaromatic moieties present in both classes of compounds suggested a common binding mode. The mutation of either tryptophan 494 or tyrosine 596, located near the active site of the protein, reduced the Ki of the inhibitors from 3- to 18-fold, indicating that these residues may help to promote the binding of substrates with aromatic groups. This work provides new insights into substrate selectivity mechanisms and describes two classes of compounds that can serve as probes of function or as a basis for future drug discovery.
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Affiliation(s)
| | | | - Emery Smith
- Department of Molecular Medicine, Scripps Research Molecular Screening Center, Scripps Research, 130 Scripps Way, Jupiter, Florida 33458, United States
| | | | - Justin Shumate
- Department of Molecular Medicine, Scripps Research Molecular Screening Center, Scripps Research, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Louis Scampavia
- Department of Molecular Medicine, Scripps Research Molecular Screening Center, Scripps Research, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Timothy P. Spicer
- Department of Molecular Medicine, Scripps Research Molecular Screening Center, Scripps Research, 130 Scripps Way, Jupiter, Florida 33458, United States
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Abstract
Francisella tularensis is a highly infectious intracellular pathogen that kills more than half of infected humans if left untreated. F. tularensis has also been classified as a potential bioterrorism agent with a great risk for deliberate misuse. Recently, compounds that inhibit ribosome rescue have been shown to have antibiotic activity against F. tularensis and other important pathogens. Like all bacteria that have been studied, F. tularensis uses trans-translation as the main pathway to rescue stalled ribosomes. However, unlike most bacteria, F. tularensis can survive without any of the known factors for ribosome rescue. Our work identified a F. tularensis protein, ArfT, that rescues stalled ribosomes in the absence of trans-translation using a new mechanism. These results indicate that ribosome rescue activity is essential in F. tularensis and suggest that ribosome rescue activity might be essential in all bacteria. Bacterial ribosomes frequently translate to the 3′ end of an mRNA without terminating at an in-frame stop codon. In all bacteria studied to date, these “nonstop” ribosomes are rescued using trans-translation. Genes required for trans-translation are essential in some species, but other species can survive without trans-translation because they express an alternative ribosome rescue factor, ArfA or ArfB. Francisella tularensis cells lacking trans-translation are viable, but F. tularensis does not encode ArfA or ArfB. Transposon mutagenesis followed by deep sequencing (Tn-seq) identified a new alternative ribosome rescue factor, now named ArfT. arfT can be deleted in wild-type (wt) cells but not in cells that lack trans-translation activity. Overexpression of ArfT suppresses the slow-growth phenotype in cells lacking trans-translation and counteracts growth arrest caused by trans-translation inhibitors, indicating that ArfT rescues nonstop ribosomes in vivo. Ribosome rescue assays in vitro show that ArfT promotes hydrolysis of peptidyl-tRNA on nonstop ribosomes in conjunction with F. tularensis release factors. Unlike ArfA, which requires RF2 for activity, ArfT can function with either RF1 or RF2. Overall, these results indicate that ArfT is a new alternative ribosome rescue factor with a distinct mechanism from ArfA and ArfB.
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25
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Cieślik P, Knap J, Piechowicz L, Bielawska-Drózd A. Subspecies differentiation and genotyping ofFrancisella tularensisstrains isolated from clinical and environmental samples. Lett Appl Microbiol 2018; 67:550-556. [DOI: 10.1111/lam.13063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 04/16/2018] [Accepted: 08/09/2018] [Indexed: 12/20/2022]
Affiliation(s)
- P. Cieślik
- Biological Threats Identification and Countermeasure Center; Military Institute of Hygiene and Epidemiology; Puławy Poland
| | - J.P. Knap
- Department of Epidemiology; Medical University of Warsaw; Warsaw Poland
| | - L. Piechowicz
- Department of Medical Microbiology; Medical University of Gdańsk; Gdańsk Poland
| | - A. Bielawska-Drózd
- Biological Threats Identification and Countermeasure Center; Military Institute of Hygiene and Epidemiology; Puławy Poland
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26
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Rasti B, Mazraedoost S, Panahi H, Falahati M, Attar F. New insights into the selective inhibition of the β-carbonic anhydrases of pathogenic bacteria Burkholderia pseudomallei and Francisella tularensis: a proteochemometrics study. Mol Divers 2018; 23:263-273. [PMID: 30120657 DOI: 10.1007/s11030-018-9869-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/09/2018] [Indexed: 10/28/2022]
Abstract
Nowadays, antibiotic resistance has turned into one of the most important worldwide health problems. Biological end point of critical enzymes induced by potent inhibitors is recently being considered as a highly effective and popular strategy to defeat antibiotic-resistant pathogens. For instance, the simple but critical β-carbonic anhydrase has recently been in the center of attention for anti-pathogen drug discoveries. However, no β-carbonic anhydrase selective inhibitor has yet been developed. Available β-carbonic anhydrase inhibitors are also highly potent with regard to human carbonic anhydrases, leading to severe inevitable side effects in case of usage. Therefore, developing novel inhibitors with high selectivity against pathogenic β-carbonic anhydrases is of great essence. Herein, for the first time, we have conducted a proteochemometric study to explore the structural and the chemical aspects of the interactions governed by bacterial β-carbonic anhydrases and their inhibitors. We have found valuable information which can lead to designing novel inhibitors with better selectivity for bacterial β-carbonic anhydrases.
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Affiliation(s)
- Behnam Rasti
- Department of Microbiology, Faculty of Basic Sciences, Lahijan Branch, Islamic Azad University (IAU), Lahijan, Guilan, Iran.
| | - Sargol Mazraedoost
- Department of Microbiology, Faculty of Basic Sciences, Lahijan Branch, Islamic Azad University (IAU), Lahijan, Guilan, Iran
| | - Hanieh Panahi
- Department of Mathematics and Statistics, Lahijan Branch, Islamic Azad University, Lahijan, Iran
| | - Mojtaba Falahati
- Department of Nanotechnology, Faculty of Advance Science and Technology, Pharmaceutical Sciences Branch, Islamic Azad University (IAUPS), Tehran, Iran
| | - Farnoosh Attar
- Department of Biology, Faculty of Food Industry and Agriculture, Standard Research Institute (SRI), Karaj, Iran
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27
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Trottein F, Paget C. Natural Killer T Cells and Mucosal-Associated Invariant T Cells in Lung Infections. Front Immunol 2018; 9:1750. [PMID: 30116242 PMCID: PMC6082944 DOI: 10.3389/fimmu.2018.01750] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 07/16/2018] [Indexed: 12/13/2022] Open
Abstract
The immune system has been traditionally divided into two arms called innate and adaptive immunity. Typically, innate immunity refers to rapid defense mechanisms that set in motion within minutes to hours following an insult. Conversely, the adaptive immune response emerges after several days and relies on the innate immune response for its initiation and subsequent outcome. However, the recent discovery of immune cells displaying merged properties indicates that this distinction is not mutually exclusive. These populations that span the innate-adaptive border of immunity comprise, among others, CD1d-restricted natural killer T cells and MR1-restricted mucosal-associated invariant T cells. These cells have the unique ability to swiftly activate in response to non-peptidic antigens through their T cell receptor and/or to activating cytokines in order to modulate many aspects of the immune response. Despite they recirculate all through the body via the bloodstream, these cells mainly establish residency at barrier sites including lungs. Here, we discuss the current knowledge into the biology of these cells during lung (viral and bacterial) infections including activation mechanisms and functions. We also discuss future strategies targeting these cell types to optimize immune responses against respiratory pathogens.
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Affiliation(s)
- François Trottein
- Univ. Lille, U1019 – UMR 8204 – CIIL – Centre d’Infection et d’Immunité de Lille, Lille, France
- Centre National de la Recherche Scientifique, UMR 8204, Lille, France
- Institut National de la Santé et de la Recherche Médicale U1019, Lille, France
- Centre Hospitalier Universitaire de Lille, Lille, France
- Institut Pasteur de Lille, Lille, France
| | - Christophe Paget
- Institut National de la Santé et de la Recherche Médicale U1100, Centre d’Etude des Pathologies Respiratoires (CEPR), Tours, France
- Université de Tours, Tours, France
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28
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Carruthers J, López-García M, Gillard JJ, Laws TR, Lythe G, Molina-París C. A Novel Stochastic Multi-Scale Model of Francisella tularensis Infection to Predict Risk of Infection in a Laboratory. Front Microbiol 2018; 9:1165. [PMID: 30034369 PMCID: PMC6043654 DOI: 10.3389/fmicb.2018.01165] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 05/14/2018] [Indexed: 12/30/2022] Open
Abstract
We present a multi-scale model of the within-phagocyte, within-host and population-level infection dynamics of Francisella tularensis, which extends the mechanistic one proposed by Wood et al. (2014). Our multi-scale model incorporates key aspects of the interaction between host phagocytes and extracellular bacteria, accounts for inter-phagocyte variability in the number of bacteria released upon phagocyte rupture, and allows one to compute the probability of response, and mean time until response, of an infected individual as a function of the initial infection dose. A Bayesian approach is applied to parameterize both the within-phagocyte and within-host models using infection data. Finally, we show how dose response probabilities at the individual level can be used to estimate the airborne propagation of Francisella tularensis in indoor settings (such as a microbiology laboratory) at the population level, by means of a deterministic zonal ventilation model.
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Affiliation(s)
- Jonathan Carruthers
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds, United Kingdom
| | - Martín López-García
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds, United Kingdom
| | - Joseph J. Gillard
- Defence Science and Technology Laboratory, Salisbury, United Kingdom
| | - Thomas R. Laws
- Defence Science and Technology Laboratory, Salisbury, United Kingdom
| | - Grant Lythe
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds, United Kingdom
| | - Carmen Molina-París
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds, United Kingdom
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29
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Champion AE, Bandara AB, Mohapatra N, Fulton KM, Twine SM, Inzana TJ. Further Characterization of the Capsule-Like Complex (CLC) Produced by Francisella tularensis Subspecies tularensis: Protective Efficacy and Similarity to Outer Membrane Vesicles. Front Cell Infect Microbiol 2018; 8:182. [PMID: 29963499 PMCID: PMC6013578 DOI: 10.3389/fcimb.2018.00182] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 05/09/2018] [Indexed: 11/17/2022] Open
Abstract
Francisella tularensis is the etiologic agent of tularemia, and subspecies tularensis (type A) is the most virulent subspecies. The live vaccine strain (LVS) of subspecies holarctica produces a capsule-like complex (CLC) that consists of a large variety of glycoproteins. Expression of the CLC is greatly enhanced when the bacteria are subcultured in and grown on chemically defined medium. Deletion of two genes responsible for CLC glycosylation in LVS results in an attenuated mutant that is protective against respiratory tularemia in a mouse model. We sought to further characterize the CLC composition and to determine if a type A CLC glycosylation mutant would be attenuated in mice. The CLCs isolated from LVS extracted with 0.5% phenol or 1 M urea were similar, as determined by gel electrophoresis and Western blotting, but the CLC extracted with urea was more water-soluble. The CLC extracted with either 0.5% phenol or 1 M urea from type A strains was also similar to the CLC of LVS in antigenic properties, electrophoretic profile, and by transmission electron microscopy (TEM). The solubility of the CLC could be further enhanced by fractionation with Triton X-114 followed by N-Lauroylsarcosine detergents; the largest (>250 kDa) molecular size component appeared to be an aggregate of smaller components. Outer membrane vesicles/tubules (OMV/T) isolated by differential centrifugation and micro-filtration appeared similar to the CLC by TEM, and many of the proteins present in the OMV/T were also identified in soluble and insoluble fractions of the CLC. Further investigation is warranted to assess the relationship between OMV/T and the CLC. The CLC conjugated to keyhole limpet hemocyanin or flagellin was highly protective against high-dose LVS intradermal challenge and partially protective against intranasal challenge. A protective response was associated with a significant rise in cytokines IL-12, IL-10, and IFN-γ. However, a type A CLC glycosylation mutant remained virulent in BALB/c mice, and immunization with the CLC did not protect mice against high dose respiratory challenge with type A strain SCHU S4.
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MESH Headings
- Administration, Intranasal
- Animals
- Antigens, Bacterial/genetics
- Antigens, Bacterial/immunology
- Bacterial Capsules/genetics
- Bacterial Capsules/immunology
- Bacterial Vaccines/genetics
- Bacterial Vaccines/immunology
- Cytokines/metabolism
- Disease Models, Animal
- Flagellin/genetics
- Flagellin/immunology
- Francisella tularensis/genetics
- Francisella tularensis/metabolism
- Francisella tularensis/pathogenicity
- Genes, Bacterial/genetics
- Glycoproteins/genetics
- Glycoproteins/immunology
- Glycoproteins/isolation & purification
- Hemocyanins/genetics
- Hemocyanins/immunology
- Interferon-gamma/metabolism
- Interleukin-10/metabolism
- Interleukin-12/metabolism
- Mice, Inbred BALB C
- Mutagenesis
- Sequence Deletion
- Tularemia/immunology
- Tularemia/prevention & control
- Vaccination
- Vaccines, Attenuated/genetics
- Vaccines, Attenuated/immunology
- Vaccines, Conjugate/genetics
- Vaccines, Conjugate/immunology
- Virulence Factors/genetics
- Virulence Factors/immunology
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Affiliation(s)
- Anna E. Champion
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States
| | - Aloka B. Bandara
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States
| | - Nrusingh Mohapatra
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States
| | - Kelly M. Fulton
- Institute for Biological Sciences, National Research Council Canada, Ottawa, ON, Canada
| | - Susan M. Twine
- Institute for Biological Sciences, National Research Council Canada, Ottawa, ON, Canada
| | - Thomas J. Inzana
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States
- Virginia Tech Carilion School of Medicine, Roanoke, VA, United States
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30
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Pavithra GC, Ramagopal UA. Crystal structures of APRT from Francisella tularensis - an N-H···N hydrogen bond imparts adenine specificity in adenine phosporibosyltransferases. FEBS J 2018; 285:2306-2318. [PMID: 29694705 DOI: 10.1111/febs.14481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 03/24/2018] [Accepted: 04/18/2018] [Indexed: 11/27/2022]
Abstract
Francisella tularensisis, the causative agent of tularemia has been classified as a category A bioterrorism agent. Here, we present the crystal structure of apo and adenine bound form of the adenine phosphoribosyltransferase (APRT) from Francisella tularensis. APRT is an enzyme involved in the salvage of adenine (a 6-aminopurine), converting it to AMP. The purine salvage pathway relies on two essential and distinct enzymes to convert 6-aminopurine and 6-oxopurines into corresponding nucleotides. The mechanism by which these enzymes differentiate different purines is not clearly understood. Analysis of the structures of apo and adenine-bound APRT from F. tularensis, together with all other available structures of APRTs, suggests that (a) the base-binding loop is stabilized by a cluster of aromatic and conformation-restricting proline residues, and (b) an N-H···N hydrogen bond between the base-binding loop and the N1 atom of adenine is the key interaction that differentiates adenine from 6-oxopurines. These observations were corroborated by bioinformatics analysis of ~ 4000 sequences of APRTs (with 80% identity cutoff), which confirmed that the residues conferring rigidity to the base-binding loop are highly conserved. Furthermore, an F23A mutation on the base-binding loop severely affects the efficiency of the enzyme. We extended our analysis to the structure and sequences of APRTs from the Trypanosomatidae family with a destabilizing insertion on the base-binding loop and propose the mechanism by which these evolutionarily divergent enzymes achieve base specificity. Our results suggest that the base-binding loop not only confers appropriate affinity but also provides defined specificity for adenine. ENZYME EC 2.4.2.7 DATABASE: Structural data are available in Protein Data Bank (PDB) under the accession numbers 5YW2 and 5YW5.
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Affiliation(s)
- Gowribidanur C Pavithra
- Division of Biological Sciences, Poornaprajna Institute of Scientific Research, Bangalore, India.,Manipal Academy of Higher Education, Karnataka, India
| | - Udupi A Ramagopal
- Division of Biological Sciences, Poornaprajna Institute of Scientific Research, Bangalore, India
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31
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Hoang KV, Rajaram MVS, Curry HM, Gavrilin MA, Wewers MD, Schlesinger LS. Complement Receptor 3-Mediated Inhibition of Inflammasome Priming by Ras GTPase-Activating Protein During Francisella tularensis Phagocytosis by Human Mononuclear Phagocytes. Front Immunol 2018; 9:561. [PMID: 29632532 PMCID: PMC5879101 DOI: 10.3389/fimmu.2018.00561] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 03/06/2018] [Indexed: 01/08/2023] Open
Abstract
Francisella tularensis is a remarkably infectious facultative intracellular bacterium of macrophages that causes tularemia. Early evasion of host immune responses contributes to the success of F. tularensis as a pathogen. F. tularensis entry into human monocytes and macrophages is mediated by the major phagocytic receptor, complement receptor 3 (CR3, CD11b/CD18). We recently determined that despite a significant increase in macrophage uptake following C3 opsonization of the virulent Type A F. tularensis spp. tularensis Schu S4, this phagocytic pathway results in limited pro-inflammatory cytokine production. Notably, MAP kinase/ERK activation is suppressed immediately during C3-opsonized Schu S4-CR3 phagocytosis. A mathematical model of CR3-TLR2 crosstalk predicted early involvement of Ras GTPase-activating protein (RasGAP) in immune suppression by CR3. Here, we link CR3-mediated uptake of opsonized Schu S4 by human monocytes and macrophages with inhibition of early signal 1 inflammasome activation, evidenced by limited caspase-1 cleavage and IL-18 release. This inhibition is due to increased RasGAP activity, leading to a reduction in the Ras-ERK signaling cascade upstream of the early inflammasome activation event. Thus, our data uncover a novel signaling pathway mediated by CR3 following engagement of opsonized virulent F. tularensis to limit inflammasome activation in human phagocytic cells, thereby contributing to evasion of the host innate immune system.
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Affiliation(s)
- Ky V Hoang
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, United States
| | - Murugesan V S Rajaram
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, United States
| | - Heather Marie Curry
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, United States
| | - Mikhail A Gavrilin
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Internal Medicine, Davis Heart & Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Mark D Wewers
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Internal Medicine, Davis Heart & Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Larry S Schlesinger
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, United States.,Texas Biomedical Research Institute, San Antonio, TX, United States
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Trivedi NH, Yu JJ, Hung CY, Doelger RP, Navara CS, Armitige LY, Seshu J, Sinai AP, Chambers JP, Guentzel MN, Arulanandam BP. Microbial co-infection alters macrophage polarization, phagosomal escape, and microbial killing. Innate Immun 2018; 24:152-162. [PMID: 29482417 PMCID: PMC6852389 DOI: 10.1177/1753425918760180] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Macrophages are important innate immune cells that respond to microbial insults.
In response to multi-bacterial infection, the macrophage activation state may
change upon exposure to nascent mediators, which results in different bacterial
killing mechanism(s). In this study, we utilized two respiratory bacterial
pathogens, Mycobacterium bovis (Bacillus Calmette
Guẻrin, BCG) and Francisella tularensis live
vaccine strain (LVS) with different phagocyte evasion mechanisms, as model
microbes to assess the influence of initial bacterial infection on the
macrophage response to secondary infection. Non-activated (M0) macrophages or
activated M2-polarized cells (J774 cells transfected with the mouse IL-4 gene)
were first infected with BCG for 24–48 h, subsequently challenged with LVS, and
the results of inhibition of LVS replication in the macrophages was assessed.
BCG infection in M0 macrophages activated TLR2-MyD88 and Mincle-CARD9 signaling
pathways, stimulating nitric oxide (NO) production and enhanced killing of LVS.
BCG infection had little effect on LVS escape from phagosomes into the cytosol
in M0 macrophages. In contrast, M2-polarized macrophages exhibited enhanced
endosomal acidification, as well as inhibiting LVS replication. Pre-infection
with BCG did not induce NO production and thus did not further reduce LVS
replication. This study provides a model for studies of the complexity of
macrophage activation in response to multi-bacterial infection.
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Affiliation(s)
- Nikita H Trivedi
- 1 Department of Biology, the South Texas Center for Emerging Infectious Diseases, and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, USA
| | - Jieh-Juen Yu
- 1 Department of Biology, the South Texas Center for Emerging Infectious Diseases, and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, USA
| | - Chiung-Yu Hung
- 1 Department of Biology, the South Texas Center for Emerging Infectious Diseases, and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, USA
| | - Richard P Doelger
- 1 Department of Biology, the South Texas Center for Emerging Infectious Diseases, and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, USA
| | - Christopher S Navara
- 1 Department of Biology, the South Texas Center for Emerging Infectious Diseases, and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, USA
| | | | - Janakiram Seshu
- 1 Department of Biology, the South Texas Center for Emerging Infectious Diseases, and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, USA
| | - Anthony P Sinai
- 3 The Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, USA
| | - James P Chambers
- 1 Department of Biology, the South Texas Center for Emerging Infectious Diseases, and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, USA
| | - M Neal Guentzel
- 1 Department of Biology, the South Texas Center for Emerging Infectious Diseases, and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, USA
| | - Bernard P Arulanandam
- 1 Department of Biology, the South Texas Center for Emerging Infectious Diseases, and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, USA
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Murch AL, Skipp PJ, Roach PL, Oyston PCF. Whole genome transcriptomics reveals global effects including up-regulation of Francisella pathogenicity island gene expression during active stringent response in the highly virulent Francisella tularensis subsp. tularensis SCHU S4. MICROBIOLOGY-SGM 2017; 163:1664-1679. [PMID: 29034854 PMCID: PMC5845702 DOI: 10.1099/mic.0.000550] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
During conditions of nutrient limitation bacteria undergo a series of global gene expression changes to survive conditions of amino acid and fatty acid starvation. Rapid reallocation of cellular resources is brought about by gene expression changes coordinated by the signalling nucleotides' guanosine tetraphosphate or pentaphosphate, collectively termed (p)ppGpp and is known as the stringent response. The stringent response has been implicated in bacterial virulence, with elevated (p)ppGpp levels being associated with increased virulence gene expression. This has been observed in the highly pathogenic Francisella tularensis sub spp. tularensis SCHU S4, the causative agent of tularaemia. Here, we aimed to artificially induce the stringent response by culturing F. tularensis in the presence of the amino acid analogue l-serine hydroxamate. Serine hydroxamate competitively inhibits tRNAser aminoacylation, causing an accumulation of uncharged tRNA. The uncharged tRNA enters the A site on the translating bacterial ribosome and causes ribosome stalling, in turn stimulating the production of (p)ppGpp and activation of the stringent response. Using the essential virulence gene iglC, which is encoded on the Francisella pathogenicity island (FPI) as a marker of active stringent response, we optimized the culture conditions required for the investigation of virulence gene expression under conditions of nutrient limitation. We subsequently used whole genome RNA-seq to show how F. tularensis alters gene expression on a global scale during active stringent response. Key findings included up-regulation of genes involved in virulence, stress responses and metabolism, and down-regulation of genes involved in metabolite transport and cell division. F. tularensis is a highly virulent intracellular pathogen capable of causing debilitating or fatal disease at extremely low infectious doses. However, virulence mechanisms are still poorly understood. The stringent response is widely recognized as a diverse and complex bacterial stress response implicated in virulence. This work describes the global gene expression profile of F. tularensis SCHU S4 under active stringent response for the first time. Herein we provide evidence for an association of active stringent response with FPI virulence gene expression. Our results further the understanding of the molecular basis of virulence and regulation thereof in F. tularensis. These results also support research into genes involved in (p)ppGpp production and polyphosphate biosynthesis and their applicability as targets for novel antimicrobials.
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Affiliation(s)
- Amber L Murch
- CBR Division, Defence Science and Technology Laboratory, Salisbury, UK
| | - Paul J Skipp
- School of Chemistry, University of Southampton, Southampton, UK
| | - Peter L Roach
- School of Chemistry, University of Southampton, Southampton, UK
| | - Petra C F Oyston
- CBR Division, Defence Science and Technology Laboratory, Salisbury, UK
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Hoang KV, Adcox HE, Fitch JR, Gordon DM, Curry HM, Schlesinger LS, White P, Gunn JS. AR-13, a Celecoxib Derivative, Directly Kills Francisella In Vitro and Aids Clearance and Mouse Survival In Vivo. Front Microbiol 2017; 8:1695. [PMID: 28955308 PMCID: PMC5600997 DOI: 10.3389/fmicb.2017.01695] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 08/23/2017] [Indexed: 12/15/2022] Open
Abstract
Francisella tularensis (F. tularensis) is the causative agent of tularemia and is classified as a Tier 1 select agent. No licensed vaccine is currently available in the United States and treatment of tularemia is confined to few antibiotics. In this study, we demonstrate that AR-13, a derivative of the cyclooxygenase-2 inhibitor celecoxib, exhibits direct in vitro bactericidal killing activity against Francisella including a type A strain of F. tularensis (SchuS4) and the live vaccine strain (LVS), as well as toward the intracellular proliferation of LVS in macrophages, without causing significant host cell toxicity. Identification of an AR-13-resistant isolate indicates that this compound has an intracellular target(s) and that efflux pumps can mediate AR-13 resistance. In the mouse model of tularemia, AR-13 treatment protected 50% of the mice from lethal LVS infection and prolonged survival time from a lethal dose of F. tularensis SchuS4. Combination of AR-13 with a sub-optimal dose of gentamicin protected 60% of F. tularensis SchuS4-infected mice from death. Taken together, these data support the translational potential of AR-13 as a lead compound for the further development of new anti-Francisella agents.
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Affiliation(s)
- Ky V Hoang
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University, ColumbusOH, United States
| | - Haley E Adcox
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University, ColumbusOH, United States
| | - James R Fitch
- The Institute for Genomic Medicine, Nationwide Children's Hospital, ColumbusOH, United States
| | - David M Gordon
- The Institute for Genomic Medicine, Nationwide Children's Hospital, ColumbusOH, United States
| | - Heather M Curry
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University, ColumbusOH, United States
| | - Larry S Schlesinger
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University, ColumbusOH, United States
| | - Peter White
- The Institute for Genomic Medicine, Nationwide Children's Hospital, ColumbusOH, United States.,Department of Pediatrics, The Ohio State University College of Medicine, ColumbusOH, United States
| | - John S Gunn
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University, ColumbusOH, United States
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35
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Skyberg JA, Lacey CA. Hematopoietic MyD88 and IL-18 are essential for IFN-γ-dependent restriction of type A Francisella tularensis infection. J Leukoc Biol 2017; 102:1441-1450. [PMID: 28951422 DOI: 10.1189/jlb.4a0517-179r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 08/03/2017] [Accepted: 08/29/2017] [Indexed: 12/11/2022] Open
Abstract
Francisella tularensis is a highly infectious intracellular bacterium that causes the potentially fatal disease tularemia. We used mice with conditional MyD88 deficiencies to investigate cellular and molecular mechanisms by which MyD88 restricts type A F. tularensis infection. F. tularensis-induced weight loss was predominately dependent on MyD88 signaling in nonhematopoietic cells. In contrast, MyD88 signaling in hematopoietic cells, but not in myeloid and dendritic cells, was essential for control of F. tularensis infection in tissue. Myeloid and dendritic cell MyD88 deficiency also did not markedly impair cytokine production during infection. Although the production of IL-12 or -18 was not significantly reduced in hematopoietic MyD88-deficient mice, IFN-γ production was abolished in these animals. In addition, neutralization studies revealed that control of F. tularensis infection mediated by hematopoietic MyD88 was entirely dependent on IFN-γ. Although IL-18 production was not significantly affected by MyD88 deficiency, IL-18 was essential for IFN-γ production and restricted bacterial replication in an IFN-γ-dependent manner. Caspase-1 was also found to be partially necessary for the production of IL-18 and IFN-γ and for control of F. tularensis replication. Our collective data show that the response of leukocytes to caspase-1-dependent IL-18 via MyD88 is critical, whereas MyD88 signaling in myeloid and dendritic cells is dispensable for IFN-γ-dependent control of type A F. tularensis infection.
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Affiliation(s)
- Jerod A Skyberg
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA; and .,Laboratory for Infectious Disease Research, University of Missouri, Columbia, Missouri, USA
| | - Carolyn A Lacey
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA; and.,Laboratory for Infectious Disease Research, University of Missouri, Columbia, Missouri, USA
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36
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Characterization of a Francisella tularensis-Caenorhabditis elegans Pathosystem for the Evaluation of Therapeutic Compounds. Antimicrob Agents Chemother 2017; 61:AAC.00310-17. [PMID: 28652232 DOI: 10.1128/aac.00310-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 06/15/2017] [Indexed: 12/18/2022] Open
Abstract
Francisella tularensis is a highly infectious Gram-negative intracellular pathogen that causes tularemia. Because of its potential as a bioterrorism agent, there is a need for new therapeutic agents. We therefore developed a whole-animal Caenorhabditis elegans-F. tularensis pathosystem for high-throughput screening to identify and characterize potential therapeutic compounds. We found that the C. elegans p38 mitogen-activate protein (MAP) kinase cascade is involved in the immune response to F. tularensis, and we developed a robust F. tularensis-mediated C. elegans killing assay with a Z' factor consistently of >0.5, which was then utilized to screen a library of FDA-approved compounds that included 1,760 small molecules. In addition to clinically used antibiotics, five FDA-approved drugs were also identified as potential hits, including the anti-inflammatory drug diflunisal that showed anti-F. tularensis activity in vitro Moreover, the nonsteroidal anti-inflammatory drug (NSAID) diflunisal, at 4× MIC, blocked the replication of an F. tularensis live vaccine strain (LVS) in primary human macrophages and nonphagocytic cells. Diflunisal was nontoxic to human erythrocytes and HepG2 human liver cells at concentrations of ≥32 μg/ml. Finally, diflunisal exhibited synergetic activity with the antibiotic ciprofloxacin in both a checkerboard assay and a macrophage infection assay. In conclusion, the liquid C. elegans-F. tularensis LVS assay described here allows screening for anti-F. tularensis compounds and suggests that diflunisal could potentially be repurposed for the management of tularemia.
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37
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Increased Resistance to Intradermal Francisella tularensis LVS Infection by Inactivation of the Sts Phosphatases. Infect Immun 2017. [PMID: 28630061 DOI: 10.1128/iai.00406-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Suppressor of TCR signaling proteins (Sts-1 and Sts-2) are two homologous phosphatases that negatively regulate signaling pathways in a number of hematopoietic lineages, including T lymphocytes. Mice lacking Sts expression are characterized by enhanced T cell responses. Additionally, a recent study demonstrated that Sts-/- mice are profoundly resistant to systemic infection by Candida albicans, with resistance characterized by enhanced survival, more rapid fungal clearance in key peripheral organs, and an altered inflammatory response. To investigate the role of Sts in the primary host response to infection by a bacterial pathogen, we evaluated the response of Sts-/- mice to infection by a Gram-negative bacterial pathogen. Francisella tularensis is a facultative bacterial pathogen that replicates intracellularly within a variety of cell types and is the causative agent of tularemia. Francisella infections are characterized by a delayed immune response, followed by an intense inflammatory reaction that causes widespread tissue damage and septic shock. Herein, we demonstrate that mice lacking Sts expression are significantly resistant to infection by the live vaccine strain (LVS) of F. tularensis Resistance is characterized by reduced lethality following high-dose intradermal infection, an altered cytokine response in the spleen, and enhanced bacterial clearance in multiple peripheral organs. Sts-/- bone marrow-derived monocytes and neutrophils, infected with F. tularensis LVS ex vivo, display enhanced restriction of intracellular bacteria. These observations suggest the Sts proteins play an important regulatory role in the host response to bacterial infection, and they underscore a role for Sts in regulating functionally relevant immune response pathways.
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38
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Heppell CW, Egan JR, Hall I. A human time dose response model for Q fever. Epidemics 2017; 21:30-38. [PMID: 28666604 PMCID: PMC5729200 DOI: 10.1016/j.epidem.2017.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 05/30/2017] [Accepted: 06/07/2017] [Indexed: 12/16/2022] Open
Abstract
The causative agent of Q fever, Coxiella burnetii, has the potential to be developed for use in biological warfare and it is classified as a bioterrorism threat agent by the Centers for Disease Control and Prevention (CDC) and as a category B select agent by the National Institute of Allergy and Infectious Diseases (NIAID). In this paper we focus on the in-host properties that arise when an individual inhales a dose of C. burnetii and establish a human time-dose response model. We also propagate uncertainty throughout the model allowing us to robustly estimate key properties including the infectious dose and incubation period. Using human study data conducted in the 1950's we conclude that the dose required for a 50% probability of infection is about 15 organisms, and that one inhaled organism of C. burnetti can cause infection in 5% of the exposed population. In addition, we derive a low dose incubation period of 17.6 days and an extracellular doubling time of half a day. In conclusion this paper provides a framework for detailing the parameters and approaches that would be required for risk assessments associated with exposures to C. burnetii that might cause human infection.
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Affiliation(s)
| | - Joseph R Egan
- University of Southampton, Hampshire SO17 1BJ, United Kingdom.
| | - Ian Hall
- Public Health England, Porton, Wiltshire SP4 0JG, United Kingdom.
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Pankowski JA. Use of essential gene, encoding prophobilinogen deaminase from extreme psychrophilic Colwellia sp. C1, to generate temperature-sensitive strain of Francisella novicida. Lett Appl Microbiol 2017; 63:124-30. [PMID: 27248501 DOI: 10.1111/lam.12598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 05/25/2016] [Accepted: 05/31/2016] [Indexed: 11/28/2022]
Abstract
UNLABELLED Previously, several essential genes from psychrophilic bacteria have been substituted for their homologues in mesophilic bacterial pathogens to make the latter temperature sensitive. It has been noted that an essential ligA gene from an extreme psychrophile, Colwellia sp. C1, yielded a gene product that is inactivated at 27°C, the lowest that has been observed for any psychrophilic enzyme, and hypothesized that other essential proteins of that strain would also have low inactivation temperatures. This work describes the partial sequencing of the genome of Colwellia sp. C1 strain and the identification of 24 open reading frames encoding homologues of highly conserved bacterial essential genes. The gene encoding porphobilinogen deaminase (hemC), which is involved in the pathway of haem synthesis, has been tested for its ability to convert Francisella novicida into a temperature-sensitive strain. The hybrid strain carrying the C1-derived hemC gene exhibited a temperature-sensitive phenotype with a restrictive temperature of 36°C. These results support the conclusion that Colwellia sp. C1 is a rich source of heat-labile enzymes. SIGNIFICANCE AND IMPACT OF THE STUDY The issue of biosafety is often raised when it comes to work with pathogenic organisms. The main concern is caused by the risk of researchers being exposed to infectious doses of dangerous microbes. This paper analyses essential genes identified in partial genomic sequence of the psychrophilic bacterium Collwelia sp. C1. These sequences can be used as a mean of generating temperature-sensitive strains of pathogenic bacteria. Such strains are incapable of surviving at the temperature of human body. This means they could be applied as vaccines or for safer work with dangerous organisms.
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Affiliation(s)
- J A Pankowski
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
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40
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Effects of lipid A acyltransferases on the pathogenesis of F. novicida. Microb Pathog 2017; 109:313-318. [PMID: 28478203 DOI: 10.1016/j.micpath.2017.04.040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/20/2017] [Accepted: 04/21/2017] [Indexed: 10/19/2022]
Abstract
Francisella novicida is a gram-negative pathogen commonly used to study infections by the potential bioterrorism agent, Francisella tularensis. The Francisella lipid A structure has been well characterized and showed to affect the pathogenesis of F. novicida. Previous work characterized two lipid A acyltransferases, LpxD1 and LpxD2, and constructed the lpxD1-null and lpxD2-null mutants. Mutational analysis showed the lpxD1-null mutant was attenuated in mice and subsequently exhibited protection against a lethal WT challenge. However, details as how the virulence has been changed have remained elusive. This study aims to analyze effects of lipid A acyltransferases on the pathogenesis of F. novicida. MS and MSn were conducted to confirm the lipid A structures of lpxD1-null and lpxD2-null mutants. The stress tolerance, Toll-like receptor 4 (TLR4) stimulation level, intracellular survival and replication ability and cytotoxicity of lpxD1-null and lpxD2-null mutants were analyzed. The results suggested the lpxD1-null mutant with shorter acyl chains in lipid A is more sensitive to various environmental stresses than F. novicida and lpxD2-null mutant. In addition, the lpxD1-null mutant fails to survive and replicate in cells and shows lower cytotoxicity to infected cells. This study provides insights into the pathogenesis of F. novicida.
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Abstract
Many biological agents have been strategic pathogenic agents throughout history. Some have even changed history as a consequence of early discoveries of their use as weapons of war. Many of these bioagents can be easily isolated from the environment, and some have recently been genetically manipulated to become more pathogenic for biowarfare. However, it is difficult to determine accidental outbreaks of disease from intentional exposures. In this review, we examine how molecular tools have been used in combination with forensic research to resolve cases of unusual outbreaks and trace the source of the biocrime. New technologies are also discussed in terms of their crucial role impacting forensic science. The anthrax event of 2001 serves as an example of the real threat of bioterrorism and the employment of bioagents as weapons against a population. The Amerithrax investigation has given us lessons of the highest resolution possible with new technologies capable of distinguishing isolates at the base-pair level of sensitivity. In addition, we discuss the implications of proper sanitation to avoid waterborne diseases. The use of new methods in forensic science and health-related surveillance will be invaluable in determining the source of any new disease outbreak, and these data will allow for a quick response to any type of public health threat, whether accidental or purposely initiated.
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Whole-Genome Relationships among Francisella Bacteria of Diverse Origins Define New Species and Provide Specific Regions for Detection. Appl Environ Microbiol 2017; 83:AEM.02589-16. [PMID: 27881415 DOI: 10.1128/aem.02589-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 11/16/2016] [Indexed: 02/06/2023] Open
Abstract
Francisella tularensis is a highly virulent zoonotic pathogen that causes tularemia and, because of weaponization efforts in past world wars, is considered a tier 1 biothreat agent. Detection and surveillance of F. tularensis may be confounded by the presence of uncharacterized, closely related organisms. Through DNA-based diagnostics and environmental surveys, novel clinical and environmental Francisella isolates have been obtained in recent years. Here we present 7 new Francisella genomes and a comparison of their characteristics to each other and to 24 publicly available genomes as well as a comparative analysis of 16S rRNA and sdhA genes from over 90 Francisella strains. Delineation of new species in bacteria is challenging, especially when isolates having very close genomic characteristics exhibit different physiological features-for example, when some are virulent pathogens in humans and animals while others are nonpathogenic or are opportunistic pathogens. Species resolution within Francisella varies with analyses of single genes, multiple gene or protein sets, or whole-genome comparisons of nucleic acid and amino acid sequences. Analyses focusing on single genes (16S rRNA, sdhA), multiple gene sets (virulence genes, lipopolysaccharide [LPS] biosynthesis genes, pathogenicity island), and whole-genome comparisons (nucleotide and protein) gave congruent results, but with different levels of discrimination confidence. We designate four new species within the genus; Francisella opportunistica sp. nov. (MA06-7296), Francisella salina sp. nov. (TX07-7308), Francisella uliginis sp. nov. (TX07-7310), and Francisella frigiditurris sp. nov. (CA97-1460). This study provides a robust comparative framework to discern species and virulence features of newly detected Francisella bacteria. IMPORTANCE DNA-based detection and sequencing methods have identified thousands of new bacteria in the human body and the environment. In most cases, there are no cultured isolates that correspond to these sequences. While DNA-based approaches are highly sensitive, accurately assigning species is difficult without known near relatives for comparison. This ambiguity poses challenges for clinical cases, disease epidemics, and environmental surveillance, for which response times must be short. Many new Francisella isolates have been identified globally. However, their species designations and potential for causing human disease remain ambiguous. Through detailed genome comparisons, we identified features that differentiate F. tularensis from clinical and environmental Francisella isolates and provide a knowledge base for future comparison of Francisella organisms identified in clinical samples or environmental surveys.
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43
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Cooke FJ, Slack MP. Gram-Negative Coccobacilli. Infect Dis (Lond) 2017. [DOI: 10.1016/b978-0-7020-6285-8.00183-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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44
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Jasik KP, Okła H, Słodki J, Rozwadowska B, Słodki A, Rupik W. Congenital Tick Borne Diseases: Is This An Alternative Route of Transmission of Tick-Borne Pathogens In Mammals? Vector Borne Zoonotic Dis 2016; 15:637-44. [PMID: 26565770 DOI: 10.1089/vbz.2015.1815] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Tick-borne diseases (TBDs) have become a popular topic in many medical journals. Besides the obvious participation of ticks in the transmission of pathogens that cause TBD, little is written about alternative methods of their spread. An important role is played in this process by mammals, which serve as reservoirs. Transplacental transfer also plays important role in the spread of some TBD etiological agents. Reservoir species take part in the spread of pathogens, a phenomenon that has extreme importance in synanthropic environments. Animals that accompany humans and animals migrating from wild lands to urban areas increase the probability of pathogen infections by ticks This article provides an overview of TBDs, such as tick-borne encephalitis virus (TBEV), and TBDs caused by spirochetes, α-proteobacteria, γ-proteobacteria, and Apicomplexa, with particular attention to reports about their potential to cross the maternal placenta. For each disease, the method of propagation, symptoms of acute and chronic phase, and complications of their course in adults, children, and animals are described in detail. Additional information about transplacental transfer of these pathogens, effects of congenital diseases caused by them, and the possible effects of maternal infection to the fetus are also discussed. The problem of vertical transmission of pathogens presents a new challenge for medicine. Transfer of pathogens through the placenta may lead not only to propagation of diseases in the population, but also constitute a direct threat to health and fetal development. For this reason, the problem of vertical transmission requires more attention and an estimation of the impact of placental transfer for each of listed pathogens.
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Affiliation(s)
- Krzysztof P Jasik
- 1 Department of Skin Structural Studies, Medical University of Silesia in Katowice , School of Pharmacy with Division of Laboratory Medicine in Sosnowiec, Sosnowiec, Poland
| | - Hubert Okła
- 1 Department of Skin Structural Studies, Medical University of Silesia in Katowice , School of Pharmacy with Division of Laboratory Medicine in Sosnowiec, Sosnowiec, Poland .,2 University of Silesia in Katowice, Faculty of Computer Science and Material Science, Institute of Material Science , Katowice, Poland
| | - Jan Słodki
- 1 Department of Skin Structural Studies, Medical University of Silesia in Katowice , School of Pharmacy with Division of Laboratory Medicine in Sosnowiec, Sosnowiec, Poland
| | - Beata Rozwadowska
- 1 Department of Skin Structural Studies, Medical University of Silesia in Katowice , School of Pharmacy with Division of Laboratory Medicine in Sosnowiec, Sosnowiec, Poland .,3 Provincial Sanitary and Epidemiological Station in Katowice , Katowice, Poland
| | - Aleksandra Słodki
- 1 Department of Skin Structural Studies, Medical University of Silesia in Katowice , School of Pharmacy with Division of Laboratory Medicine in Sosnowiec, Sosnowiec, Poland
| | - Weronika Rupik
- 4 Department of Animal Histology and Embryology, University of Silesia in Katowice , Faculty of Biology and Environmental Protection, Katowice, Poland
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Inhibitors of Ribosome Rescue Arrest Growth of Francisella tularensis at All Stages of Intracellular Replication. Antimicrob Agents Chemother 2016; 60:3276-82. [PMID: 26953190 DOI: 10.1128/aac.03089-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 02/23/2016] [Indexed: 11/20/2022] Open
Abstract
Bacteria require at least one pathway to rescue ribosomes stalled at the ends of mRNAs. The primary pathway for ribosome rescue is trans-translation, which is conserved in >99% of sequenced bacterial genomes. Some species also have backup systems, such as ArfA or ArfB, which can rescue ribosomes in the absence of sufficient trans-translation activity. Small-molecule inhibitors of ribosome rescue have broad-spectrum antimicrobial activity against bacteria grown in liquid culture. These compounds were tested against the tier 1 select agent Francisella tularensis to determine if they can limit bacterial proliferation during infection of eukaryotic cells. The inhibitors KKL-10 and KKL-40 exhibited exceptional antimicrobial activity against both attenuated and fully virulent strains of F. tularensis in vitro and during ex vivo infection. Addition of KKL-10 or KKL-40 to macrophages or liver cells at any time after infection by F. tularensis prevented further bacterial proliferation. When macrophages were stimulated with the proinflammatory cytokine gamma interferon before being infected by F. tularensis, addition of KKL-10 or KKL-40 reduced intracellular bacteria by >99%, indicating that the combination of cytokine-induced stress and a nonfunctional ribosome rescue pathway is fatal to F. tularensis Neither KKL-10 nor KKL-40 was cytotoxic to eukaryotic cells in culture. These results demonstrate that ribosome rescue is required for F. tularensis growth at all stages of its infection cycle and suggest that KKL-10 and KKL-40 are good lead compounds for antibiotic development.
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Abstract
Francisella tularensis is the causative agent of the potentially lethal disease tularemia. Due to a low infectious dose and ease of airborne transmission, Francisella is classified as a category A biological agent. Despite the possible risk to public health, there is no safe and fully licensed vaccine. A potential vaccine candidate, an attenuated live vaccine strain, does not fulfil the criteria for general use. In this review, we will summarize existing and new candidates for live attenuated and subunit vaccines.
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Gunnell MK, Robison RA, Adams BJ. Natural Selection in Virulence Genes of Francisella tularensis. J Mol Evol 2016; 82:264-78. [PMID: 27177502 DOI: 10.1007/s00239-016-9743-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 04/29/2016] [Indexed: 02/06/2023]
Abstract
A fundamental tenet of evolution is that alleles that are under negative selection are often deleterious and confer no evolutionary advantage. Negatively selected alleles are removed from the gene pool and are eventually extinguished from the population. Conversely, alleles under positive selection do confer an evolutionary advantage and lead to an increase in the overall fitness of the organism. These alleles increase in frequency until they eventually become fixed in the population. Francisella tularensis is a zoonotic pathogen and a potential biothreat agent. The most virulent type of F. tularensis, Type A, is distributed across North America with Type A.I occurring mainly in the east and Type A.II appearing mainly in the west. F. tularensis is thought to be a genome in decay (losing genes) because of the relatively large number of pseudogenes present in its genome. We hypothesized that the observed frequency of gene loss/pseudogenes may be an artifact of evolution in response to a changing environment, and that genes involved in virulence should be under strong positive selection. To test this hypothesis, we sequenced and compared whole genomes of Type A.I and A.II isolates. We analyzed a subset of virulence and housekeeping genes from several F. tularensis subspecies genomes to ascertain the presence and extent of positive selection. Eleven previously identified virulence genes were screened for positive selection along with 10 housekeeping genes. Analyses of selection yielded one housekeeping gene and 7 virulence genes which showed significant evidence of positive selection at loci implicated in cell surface structures and membrane proteins, metabolism and biosynthesis, transcription, translation and cell separation, and substrate binding and transport. Our results suggest that while the loss of functional genes through disuse could be accelerated by negative selection, the genome decay in Francisella could also be the byproduct of adaptive evolution driven by complex interactions between host, pathogen, and thier environment, as evidenced by several of its virulence genes which are undergoing strong, positive selection.
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Affiliation(s)
- Mark K Gunnell
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, USA. .,Microbiology Branch, Life Sciences Division, Dugway Proving Ground, Dugway, UT, 84022, USA.
| | - Richard A Robison
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, USA
| | - Byron J Adams
- Department of Biology, Brigham Young University, Provo, UT, 84602, USA
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Hoang KV, Chen CG, Koopman J, Moshiri J, Adcox HE, Gunn JS. Identification of Genes Required for Secretion of the Francisella Oxidative Burst-Inhibiting Acid Phosphatase AcpA. Front Microbiol 2016; 7:605. [PMID: 27199935 PMCID: PMC4848305 DOI: 10.3389/fmicb.2016.00605] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 04/11/2016] [Indexed: 11/13/2022] Open
Abstract
Francisella tularensis is a Tier 1 bioterror threat and the intracellular pathogen responsible for tularemia in humans and animals. Upon entry into the host, Francisella uses multiple mechanisms to evade killing. Our previous studies have shown that after entering its primary cellular host, the macrophage, Francisella immediately suppresses the oxidative burst by secreting a series of acid phosphatases including AcpA-B-C and HapA, thereby evading the innate immune response of the macrophage and enhancing survival and further infection. However, the mechanism of acid phosphatase secretion by Francisella is still unknown. In this study, we screened for genes required for AcpA secretion in Francisella. We initially demonstrated that the known secretion systems, the putative Francisella-pathogenicity island (FPI)-encoded Type VI secretion system and the Type IV pili, do not secrete AcpA. Using random transposon mutagenesis in conjunction with ELISA, Western blotting and acid phosphatase enzymatic assays, a transposon library of 5450 mutants was screened for strains with a minimum 1.5-fold decrease in secreted (culture supernatant) AcpA, but no defect in cytosolic AcpA. Three mutants with decreased supernatant AcpA were identified. The transposon insertion sites of these mutants were revealed by direct genomic sequencing or inverse-PCR and sequencing. One of these mutants has a severe defect in AcpA secretion (at least 85% decrease) and is a predicted hypothetical inner membrane protein. Interestingly, this mutant also affected the secretion of the FPI-encoded protein, VgrG. Thus, this screen identified novel protein secretion factors involved in the subversion of host defenses.
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Affiliation(s)
- Ky Van Hoang
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University Columbus, OH, USA
| | - Carolyn G Chen
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University Columbus, OH, USA
| | - Jacob Koopman
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University Columbus, OH, USA
| | - Jasmine Moshiri
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University Columbus, OH, USA
| | - Haley E Adcox
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University Columbus, OH, USA
| | - John S Gunn
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University Columbus, OH, USA
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Abstract
We report on a 13-year-old patient who developed ulceroglandular tularemia after having assisted in slaughtering a hunted boar. He presented with a digital skin ulcer and enlarged lymph nodes. Clinically suspected tularemia was proven by real-time polymerase chain reaction performed on a skin ulcer biopsy and swab and by positive serology. This is the first reported case of tularemia after contact with a boar.
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Kunda NK, Wafula D, Tram M, Wu TH, Muttil P. A stable live bacterial vaccine. Eur J Pharm Biopharm 2016; 103:109-117. [PMID: 27020530 DOI: 10.1016/j.ejpb.2016.03.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 03/04/2016] [Accepted: 03/23/2016] [Indexed: 01/31/2023]
Abstract
Formulating vaccines into a dry form enhances its thermal stability. This is critical to prevent administering damaged and ineffective vaccines, and to reduce its final cost. A number of vaccines in the market as well as those being evaluated in the clinical setting are in a dry solid state; yet none of these vaccines have achieved long-term stability at high temperatures. We used spray-drying to formulate a recombinant live attenuated Listeria monocytogenes (Lm; expressing Francisella tularensis immune protective antigen pathogenicity island protein IglC) bacterial vaccine into a thermostable dry powder using various sugars and an amino acid. Lm powder vaccine showed minimal loss in viability when stored for more than a year at ambient room temperature (∼23°C) or for 180days at 40°C. High temperature viability was achieved by maintaining an inert atmosphere in the storage container and removing oxygen free radicals that damage bacterial membranes. Further, in vitro antigenicity was confirmed by infecting a dendritic cell line with cultures derived from spray dried Lm and detection of an intracellularly expressed protective antigen. A combination of stabilizing excipients, a cost effective one-step drying process, and appropriate storage conditions could provide a viable option for producing, storing and transporting heat-sensitive vaccines, especially in regions of the world that require them the most.
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Affiliation(s)
- Nitesh K Kunda
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico, Albuquerque, NM, USA
| | - Denis Wafula
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico, Albuquerque, NM, USA; Department of Cell Biology and Molecular Genetics, University of Maryland, MD, USA
| | - Meilinn Tram
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico, Albuquerque, NM, USA
| | - Terry H Wu
- Department of Internal Medicine, University of New Mexico, Albuquerque, NM, USA; Center for Infectious Disease and Immunity, University of New Mexico, Albuquerque, NM, USA
| | - Pavan Muttil
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico, Albuquerque, NM, USA.
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