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Unni R, Pintor KL, Diepold A, Unterweger D. Presence and absence of type VI secretion systems in bacteria. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35467500 DOI: 10.1099/mic.0.001151] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The type VI secretion system (T6SS) is a molecular puncturing device that enables Gram-negative bacteria to kill competitors, manipulate host cells and take up nutrients. Who would want to miss such superpowers? Indeed, many studies show how widespread the secretion apparatus is among microbes. However, it is becoming evident that, on multiple taxonomic levels, from phyla to species and strains, some bacteria lack a T6SS. Here, we review who does and does not have a type VI secretion apparatus and speculate on the dynamic process of gaining and losing the secretion system to better understand its spread and distribution across the microbial world.
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Affiliation(s)
- Rahul Unni
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Straße 2, 24306 Plön, Germany.,Institute for Experimental Medicine, Kiel University, Michaelisstraße 5, 24105 Kiel, Germany
| | - Katherine L Pintor
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, 35043 Marburg, Germany
| | - Andreas Diepold
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, 35043 Marburg, Germany
| | - Daniel Unterweger
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Straße 2, 24306 Plön, Germany.,Institute for Experimental Medicine, Kiel University, Michaelisstraße 5, 24105 Kiel, Germany
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2
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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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3
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Using proteomics to identify host cell interaction partners for VgrG and IglJ. Sci Rep 2020; 10:14612. [PMID: 32884055 PMCID: PMC7471685 DOI: 10.1038/s41598-020-71641-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/23/2020] [Indexed: 11/17/2022] Open
Abstract
Francisella tularensis is a highly virulent intracellular bacterium and the causative agent of tularemia. The disease is characterized by the suboptimal innate immune response and consequently by the impaired adaptive immunity. The virulence of this pathogen depends on proteins encoded by a genomic island termed the Francisella Pathogenicity Island (FPI). However, the precise biological roles of most of the FPI-encoded proteins remain to be clarified. In this study, we employed stable isotope labeling by amino acids in cell culture (SILAC) in combination with affinity protein purification coupled with liquid chromatography–mass spectrometry to identify potential protein-effector binding pairs for two FPI virulence effectors IglJ and VgrG. Our results may indicate that while the IglJ protein interactions primarily affect mitochondria, the VgrG interactions affect phagosome and/or autophagosome biogenesis via targeting components of the host’s exocyst complex.
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Pereira FL, Tavares GC, de Carvalho AF, Rosa JCC, Rezende CP, Leal CAG, Figueiredo HCP. Effects of temperature changes in the transcriptional profile of the emerging fish pathogen Francisella noatunensis subsp. orientalis. Microb Pathog 2019; 133:103548. [PMID: 31112771 DOI: 10.1016/j.micpath.2019.103548] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 05/16/2019] [Accepted: 05/17/2019] [Indexed: 01/05/2023]
Abstract
One of the major challenges in Nile tilapia (Oreochromis niloticus L.) farming is the occurrence of bacterial infections, and the Francisella noatunensis subsp. orientalis (FNO) is an important pathogen that has emerged in last decades. Francisellosis outbreaks have been reported in the literature as occurring seasonally when water temperature is below 24 °C. The aim of this study was to quantify the median lethal doses (LD50) of FNO in experimental challenges at 28 °C and 22 °C, and to investigate the impact of temperature changes in whole genome expression using microarray technology. The LD50 for Nile tilapia at 28 °C was ∼105.7, whereas at 22 °C, the LD50 was ∼102.2, showing that the decrease in temperature enhanced disease outcome. Out of 1917 genes screened, a total of 31 and 19 genes were down- and up-regulated at 22 °C, respectively. These genes were grouped by orthology into functional categories of: amino acid, inorganic ion, and carbohydrate transport and metabolism; transcription; and posttranslational modification, protein turnover, and chaperones. Expression of genes related to metabolism, oxidative stress, and thermal shock were regulated by temperature changes, reflecting an ability of FNO to adapt to the environment. Expression of virulence genes usually required for the Francisella genus was not changed between tested temperatures, including that of genes located on the Francisella Pathogenicity Island.
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Affiliation(s)
- Felipe Luiz Pereira
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Guilherme Campos Tavares
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Alex Fiorini de Carvalho
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Júlio César Camara Rosa
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Cristiana Perdigão Rezende
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Carlos Augusto Gomes Leal
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Henrique César Pereira Figueiredo
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil. http://www.vet.ufmg.br/
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5
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Alam A, Golovliov I, Javed E, Sjöstedt A. ClpB mutants of Francisella tularensis subspecies holarctica and tularensis are defective for type VI secretion and intracellular replication. Sci Rep 2018; 8:11324. [PMID: 30054549 PMCID: PMC6063899 DOI: 10.1038/s41598-018-29745-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 07/17/2018] [Indexed: 12/13/2022] Open
Abstract
Francisella tularensis, a highly infectious, intracellular bacterium possesses an atypical type VI secretion system (T6SS), which is essential for the virulence of the bacterium. Recent data suggest that the HSP100 family member, ClpB, is involved in T6SS disassembly in the subspecies Francisella novicida. Here, we investigated the role of ClpB for the function of the T6SS and for phenotypic characteristics of the human pathogenic subspecies holarctica and tularensis. The ∆clpB mutants of the human live vaccine strain, LVS, belonging to subspecies holarctica, and the highly virulent SCHU S4 strain, belonging to subspecies tularensis, both showed extreme susceptibility to heat shock and low pH, severely impaired type VI secretion (T6S), and significant, but impaired intracellular replication compared to the wild-type strains. Moreover, they showed essentially intact phagosomal escape. Infection of mice demonstrated that both ΔclpB mutants were highly attenuated, but the SCHU S4 mutant showed more effective replication than the LVS strain. Collectively, our data demonstrate that ClpB performs multiple functions in the F. tularensis subspecies holarctica and tularensis and its function is important for T6S, intracellular replication, and virulence.
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Affiliation(s)
- Athar Alam
- Department of Clinical Microbiology, Umeå University, SE-901 85, Umeå, Sweden
| | - Igor Golovliov
- Department of Clinical Microbiology, Umeå University, SE-901 85, Umeå, Sweden
| | - Eram Javed
- Department of Clinical Microbiology, Umeå University, SE-901 85, Umeå, Sweden
| | - Anders Sjöstedt
- Department of Clinical Microbiology, Umeå University, SE-901 85, Umeå, Sweden.
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Milton ME, Allen CL, Feldmann EA, Bobay BG, Jung DK, Stephens MD, Melander RJ, Theisen KE, Zeng D, Thompson RJ, Melander C, Cavanagh J. Structure of the Francisella response regulator QseB receiver domain, and characterization of QseB inhibition by antibiofilm 2-aminoimidazole-based compounds. Mol Microbiol 2017; 106:223-235. [PMID: 28755524 DOI: 10.1111/mmi.13759] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2017] [Indexed: 11/29/2022]
Abstract
With antibiotic resistance increasing at alarming rates, targets for new antimicrobial therapies must be identified. A particularly promising target is the bacterial two-component system. Two-component systems allow bacteria to detect, evaluate and protect themselves against changes in the environment, such as exposure to antibiotics and also to trigger production of virulence factors. Drugs that target the response regulator portion of two-component systems represent a potent new approach so far unexploited. Here, we focus efforts on the highly virulent bacterium Francisella tularensis tularensis. Francisella contains only three response regulators, making it an ideal system to study. In this study, we initially present the structure of the N-terminal domain of QseB, the response regulator responsible for biofilm formation. Subsequently, using binding assays, computational docking and cellular studies, we show that QseB interacts with2-aminoimidazole based compounds that impede its function. This information will assist in tailoring compounds to act as adjuvants that will enhance the effect of antibiotics.
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Affiliation(s)
| | - C Leigh Allen
- Department of Structural and Molecular Biochemistry, North Carolina State University, Campus Box 7622, 128 Polk Hall, Raleigh, NC 27695, USA
| | - Erik A Feldmann
- Department of Structural and Molecular Biochemistry, North Carolina State University, Campus Box 7622, 128 Polk Hall, Raleigh, NC 27695, USA
| | - Benjamin G Bobay
- Department of Structural and Molecular Biochemistry, North Carolina State University, Campus Box 7622, 128 Polk Hall, Raleigh, NC 27695, USA
| | - David K Jung
- Agile Sciences, Keystone Science Center, 1791 Varsity Dr #150, Raleigh, NC 27606, USA
| | - Matthew D Stephens
- Department of Chemistry, North Carolina State University, Campus Box 8204, 2620 Yarborough Drive, Raleigh, NC 27695, USA
| | - Roberta J Melander
- Department of Chemistry, North Carolina State University, Campus Box 8204, 2620 Yarborough Drive, Raleigh, NC 27695, USA
| | - Kelly E Theisen
- Department of Structural and Molecular Biochemistry, North Carolina State University, Campus Box 7622, 128 Polk Hall, Raleigh, NC 27695, USA
| | - Daina Zeng
- Agile Sciences, Keystone Science Center, 1791 Varsity Dr #150, Raleigh, NC 27606, USA
| | | | - Christian Melander
- Department of Chemistry, North Carolina State University, Campus Box 8204, 2620 Yarborough Drive, Raleigh, NC 27695, USA
| | - John Cavanagh
- RTI International, 3040 Cornwallis Rd, RTP, NC 27709, USA
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7
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Marecic V, Shevchuk O, Ozanic M, Mihelcic M, Steinert M, Jurak Begonja A, Abu Kwaik Y, Santic M. Isolation of F. novicida-Containing Phagosome from Infected Human Monocyte Derived Macrophages. Front Cell Infect Microbiol 2017; 7:303. [PMID: 28725638 PMCID: PMC5496951 DOI: 10.3389/fcimb.2017.00303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/20/2017] [Indexed: 11/28/2022] Open
Abstract
Francisella is a gram-negative bacterial pathogen, which causes tularemia in humans and animals. A crucial step of Francisella infection is its invasion of macrophage cells. Biogenesis of the Francisella-containing phagosome (FCP) is arrested for ~15 min at the endosomal stage, followed by gradual bacterial escape into the cytosol, where the microbe proliferates. The crucial step in pathogenesis of tularemia is short and transient presence of the bacterium within phagosome. Isolation of FCPs for further studies has been challenging due to the short period of time of bacterial residence in it and the characteristics of the FCP. Here, we will for the first time present the method for isolation of the FCPs from infected human monocytes-derived macrophages (hMDMs). For elimination of lysosomal compartment these organelles were pre-loaded with dextran coated colloidal iron particles prior infection and eliminated by magnetic separation of the post-nuclear supernatant (PNS). We encountered the challenge that mitochondria has similar density to the FCP. To separate the FCP in the PNS from mitochondria, we utilized iodophenylnitrophenyltetrazolium, which is converted by the mitochondrial succinate dehydrogenase into formazan, leading to increased density of the mitochondria and allowing separation by the discontinuous sucrose density gradient ultracentrifugation. The purity of the FCP preparation and its acquisition of early endosomal markers was confirmed by Western blots, confocal and transmission electron microscopy. Our strategy to isolate highly pure FCPs from macrophages should facilitate studies on the FCP and its biogenesis.
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Affiliation(s)
- Valentina Marecic
- Department of Microbiology and Parasitology, Faculty of Medicine, University of RijekaRijeka, Croatia
| | - Olga Shevchuk
- Department of Microbiology, Institut für Mikrobiologie, Technische Universität Braunschweig and Helmholtz Center for Infection ResearchBraunschweig, Germany.,Department of Biotechnology, University of RijekaRijeka, Croatia
| | - Mateja Ozanic
- Department of Microbiology and Parasitology, Faculty of Medicine, University of RijekaRijeka, Croatia
| | - Mirna Mihelcic
- Department of Microbiology and Parasitology, Faculty of Medicine, University of RijekaRijeka, Croatia
| | - Michael Steinert
- Department of Microbiology, Institut für Mikrobiologie, Technische Universität Braunschweig and Helmholtz Center for Infection ResearchBraunschweig, Germany
| | | | - Yousef Abu Kwaik
- Department of Microbiology and Immunology and Center for Predictive MedicineLouisville, KY, United States
| | - Marina Santic
- Department of Microbiology and Parasitology, Faculty of Medicine, University of RijekaRijeka, Croatia
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8
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Affiliation(s)
- Petra Spidlova
- a Department of Molecular Pathology and Biology , Faculty of Military Health Sciences, University of Defence , Hradec Kralove , Czech Republic
| | - Jiri Stulik
- a Department of Molecular Pathology and Biology , Faculty of Military Health Sciences, University of Defence , Hradec Kralove , Czech Republic
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9
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Bröms JE, Meyer L, Sjöstedt A. A mutagenesis-based approach identifies amino acids in the N-terminal part of Francisella tularensis IglE that critically control Type VI system-mediated secretion. Virulence 2016; 8:821-847. [PMID: 27830989 PMCID: PMC5626337 DOI: 10.1080/21505594.2016.1258507] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The Gram-negative bacterium Francisella tularensis is the etiological agent of the zoonotic disease tularemia. Its life cycle is characterized by an ability to survive within phagocytic cells through phagosomal escape and replication in the cytosol, ultimately causing inflammasome activation and host cell death. Required for these processes is the Francisella Pathogenicity Island (FPI), which encodes a Type VI secretion system (T6SS) that is active during intracellular infection. In this study, we analyzed the role of the FPI-component IglE, a lipoprotein which we previously have shown to be secreted in a T6SS-dependent manner. We demonstrate that in F. tularensis LVS, IglE is an outer membrane protein. Upon infection of J774 cells, an ΔiglE mutant failed to escape from phagosomes, and subsequently, to multiply and cause cytopathogenicity. Moreover, ΔiglE was unable to activate the inflammasome, to inhibit LPS-stimulated secretion of TNF-α, and showed marked attenuation in the mouse model. In F. novicida, IglE was required for in vitro secretion of IglC and VgrG. A mutagenesis-based approach involving frameshift mutations and alanine substitution mutations within the first ∼ 38 residues of IglE revealed that drastic changes in the sequence of the extreme N-terminus (residues 2-6) were well tolerated and, intriguingly, caused hyper-secretion of IglE during intracellular infection, while even subtle mutations further downstream lead to impaired protein function. Taken together, this study highlights the importance of IglE in F. tularensis pathogenicity, and the contribution of the N-terminus for all of the above mentioned processes.
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Affiliation(s)
- Jeanette E Bröms
- a Department of Clinical Microbiology , Clinical Bacteriology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University , Umeå , Sweden
| | - Lena Meyer
- a Department of Clinical Microbiology , Clinical Bacteriology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University , Umeå , Sweden
| | - Anders Sjöstedt
- a Department of Clinical Microbiology , Clinical Bacteriology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University , Umeå , Sweden
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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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11
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Gonçalves LA, de Castro Soares S, Pereira FL, Dorella FA, de Carvalho AF, de Freitas Almeida GM, Leal CAG, Azevedo V, Figueiredo HCP. Complete genome sequences of Francisella noatunensis subsp. orientalis strains FNO12, FNO24 and FNO190: a fish pathogen with genomic clonal behavior. Stand Genomic Sci 2016; 11:30. [PMID: 27073591 PMCID: PMC4828924 DOI: 10.1186/s40793-016-0151-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 04/05/2016] [Indexed: 11/10/2022] Open
Abstract
The genus Francisella is composed of Gram-negative, pleomorphic, strictly aerobic and non-motile bacteria, which are capable of infecting a variety of terrestrial and aquatic animals, among which Francisella noatunensis subsp. orientalis stands out as the causative agent of pyogranulomatous and granulomatous infections in fish. Accordingly, F. noatunensis subsp. orientalis is responsible for high mortality rates in freshwater fish, especially Nile Tilapia. In the current study, we present the genome sequences of F. noatunensis subsp. orientalis strains FNO12, FNO24 and FNO190. The genomes include one circular chromosome of 1,859,720 bp, consisting of 32 % GC content, 1538 coded proteins and 363 pseudogenes for FNO12; one circular chromosome of 1,862,322 bp, consisting of 32 % GC content, 1537 coded proteins and 365 pseudogenes for FNO24; and one circular chromosome of 1,859,595 bp, consisting of 32 % GC content, 1539 coded proteins and 362 pseudogenes for FNO190. All genomes have similar genetic content, implicating a clonal-like behavior for this species.
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Affiliation(s)
- Lucas Amorim Gonçalves
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil ; Laboratory of Cellular and Molecular Genetics (LGCM), Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Siomar de Castro Soares
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Felipe Luiz Pereira
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Fernanda Alves Dorella
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Alex Fiorini de Carvalho
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Gabriel Magno de Freitas Almeida
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Carlos Augusto Gomes Leal
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Vasco Azevedo
- Laboratory of Cellular and Molecular Genetics (LGCM), Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Henrique César Pereira Figueiredo
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil
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12
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Qin A, Zhang Y, Clark ME, Moore EA, Rabideau MM, Moreau GB, Mann BJ. Components of the type six secretion system are substrates of Francisella tularensis Schu S4 DsbA-like FipB protein. Virulence 2016; 7:882-894. [PMID: 27028889 PMCID: PMC5160417 DOI: 10.1080/21505594.2016.1168550] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
FipB, an essential virulence factor in the highly virulent Schu S4 strain of F. tularensis subsp. tularensis, shares sequence similarity with Disulfide Bond formation (Dsb) proteins, which can have oxidoreductase, isomerase, or chaperone activity. To further explore FipB's role in virulence potential substrates were identified by co-purification and 2D gel electrophoresis, followed by protein sequencing using mass spectrometry. A total of 119 potential substrates were identified. Proteins with predicted enzymatic activity were prevalent, and there were 19 proteins that had been previously identified as impacting virulence. Among the potential substrates were IglC, IglB, and PdpB, three components of the Francisella Type Six Secretion System (T6SS), which is also essential for virulence. T6SS are widespread in Gram-negative pathogens, but have not been reported to be dependent on Dsb-like proteins for assembly or function. The presented results suggest that FipB affects IglB and IglC substrates differently. In a fipB mutant there were differences in free sulfhydryl accessibility of IglC, but not IglB, when compared to wild-type bacteria. However, for both proteins FipB appears to act as a chaperone that facilitates proper folding and conformation. Understanding the role FipB plays the assembly and structure in this T6SS may reveal critical aspects of assembly that are common and novel among this widely distributed class of secretion systems.
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Affiliation(s)
- Aiping Qin
- a Department of Medicine , Division of Infectious Diseases, University of Virginia , Charlottesville , VA , USA
| | - Yan Zhang
- a Department of Medicine , Division of Infectious Diseases, University of Virginia , Charlottesville , VA , USA
| | - Melinda E Clark
- a Department of Medicine , Division of Infectious Diseases, University of Virginia , Charlottesville , VA , USA
| | - Emily A Moore
- a Department of Medicine , Division of Infectious Diseases, University of Virginia , Charlottesville , VA , USA
| | - Meaghan M Rabideau
- a Department of Medicine , Division of Infectious Diseases, University of Virginia , Charlottesville , VA , USA
| | - G Brett Moreau
- a Department of Medicine , Division of Infectious Diseases, University of Virginia , Charlottesville , VA , USA
| | - Barbara J Mann
- a Department of Medicine , Division of Infectious Diseases, University of Virginia , Charlottesville , VA , USA
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Rowe HM, Huntley JF. From the Outside-In: The Francisella tularensis Envelope and Virulence. Front Cell Infect Microbiol 2015; 5:94. [PMID: 26779445 PMCID: PMC4688374 DOI: 10.3389/fcimb.2015.00094] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 12/07/2015] [Indexed: 12/20/2022] Open
Abstract
Francisella tularensis is a highly-infectious bacterium that causes the rapid, and often lethal disease, tularemia. Many studies have been performed to identify and characterize the virulence factors that F. tularensis uses to infect a wide variety of hosts and host cell types, evade immune defenses, and induce severe disease and death. This review focuses on the virulence factors that are present in the F. tularensis envelope, including capsule, LPS, outer membrane, periplasm, inner membrane, secretion systems, and various molecules in each of aforementioned sub-compartments. Whereas, no single bacterial molecule or molecular complex single-handedly controls F. tularensis virulence, we review here how diverse bacterial systems work in conjunction to subvert the immune system, attach to and invade host cells, alter phagosome/lysosome maturation pathways, replicate in host cells without being detected, inhibit apoptosis, and induce host cell death for bacterial release and infection of adjacent cells. Given that the F. tularensis envelope is the outermost layer of the bacterium, we highlight herein how many of these molecules directly interact with the host to promote infection and disease. These and future envelope studies are important to advance our collective understanding of F. tularensis virulence mechanisms and offer targets for future vaccine development efforts.
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Affiliation(s)
- Hannah M Rowe
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences Toledo, OH, USA
| | - Jason F Huntley
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences Toledo, OH, USA
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Gu Q, Li X, Qu P, Hou S, Li J, Atwill ER, Chen S. Characterization of Francisella species isolated from the cooling water of an air conditioning system. Braz J Microbiol 2015; 46:921-7. [PMID: 26413079 PMCID: PMC4568874 DOI: 10.1590/s1517-838246320140465] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 12/28/2014] [Indexed: 12/17/2022] Open
Abstract
Strains of Francisella spp. were isolated from cooling water from an
air conditioning system in Guangzhou, China. These strains are Gram negative,
coccobacilli, non-motile, oxidase negative, catalase negative, esterase and lipid
esterase positive. In addition, these bacteria grow on cysteine-supplemented media at
20 °C to 40 °C with an optimal growth temperature of 30 °C. Analysis of 16S rRNA gene
sequences revealed that these strains belong to the genus
Francisella. Biochemical tests and phylogenetic and BLAST
analyses of 16S rRNA, rpoB and sdhA genes indicated
that one strain was very similar to Francisella philomiragia and
that the other strains were identical or highly similar to the Francisella
guangzhouensis sp. nov. strain 08HL01032 we previously described.
Biochemical and molecular characteristics of these strains demonstrated that multiple
Francisella species exist in air conditioning systems.
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Affiliation(s)
- Quan Gu
- Guangzhou Center for Disease Control and Prevention, Guangzhou, China
| | - Xunde Li
- Department of Population Health and Reproduction, University of California, California, USA
| | - Pinghua Qu
- Guangdong Hospital of Traditional Chinese Medicine, University City Branch, Guangzhou, China
| | - Shuiping Hou
- Guangzhou Center for Disease Control and Prevention, Guangzhou, China
| | - Juntao Li
- Guangzhou Center for Disease Control and Prevention, Guangzhou, China
| | - Edward R Atwill
- Department of Population Health and Reproduction, University of California, California, USA
| | - Shouyi Chen
- Guangzhou Center for Disease Control and Prevention, Guangzhou, China
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