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Cantlay S, Garrison NL, Patterson R, Wagner K, Kirk Z, Fan J, Primerano DA, Sullivan MLG, Franks JM, Stolz DB, Horzempa J. Phenotypic and transcriptional characterization of F. tularensis LVS during transition into a viable but non-culturable state. Front Microbiol 2024; 15:1347488. [PMID: 38380104 PMCID: PMC10877056 DOI: 10.3389/fmicb.2024.1347488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 01/15/2024] [Indexed: 02/22/2024] Open
Abstract
Francisella tularensis is a gram-negative, intracellular pathogen which can cause serious, potentially fatal, illness in humans. Species of F. tularensis are found across the Northern Hemisphere and can infect a broad range of host species, including humans. Factors affecting the persistence of F. tularensis in the environment and its epidemiology are not well understood, however, the ability of F. tularensis to enter a viable but non-culturable state (VBNC) may be important. A broad range of bacteria, including many pathogens, have been observed to enter the VBNC state in response to stressful environmental conditions, such as nutrient limitation, osmotic or oxidative stress or low temperature. To investigate the transition into the VBNC state for F. tularensis, we analyzed the attenuated live vaccine strain, F. tularensis LVS grown under standard laboratory conditions. We found that F. tularensis LVS rapidly and spontaneously enters a VBNC state in broth culture at 37°C and that this transition coincides with morphological differentiation of the cells. The VBNC bacteria retained an ability to interact with both murine macrophages and human erythrocytes in in vitro assays and were insensitive to treatment with gentamicin. Finally, we present the first transcriptomic analysis of VBNC F. tularensis, which revealed clear differences in gene expression, and we identify sets of differentially regulated genes which are specific to the VBNC state. Identification of these VBNC specific genes will pave the way for future research aimed at dissecting the molecular mechanisms driving entry into the VBNC state.
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Affiliation(s)
- Stuart Cantlay
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, United States
| | - Nicole L. Garrison
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, United States
| | - Rachelle Patterson
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, United States
| | - Kassey Wagner
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, United States
| | - Zoei Kirk
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, United States
| | - Jun Fan
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, United States
| | - Donald A. Primerano
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, United States
| | - Mara L. G. Sullivan
- Department of Cell Biology, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA, United States
| | - Jonathan M. Franks
- Department of Cell Biology, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA, United States
| | - Donna B. Stolz
- Department of Cell Biology, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA, United States
| | - Joseph Horzempa
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, United States
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Sim EM, Wang Q, Howard P, Kim R, Lim L, Hope K, Sintchenko V. Persistent Salmonella enterica serovar Typhi sub-populations within host interrogated by whole genome sequencing and metagenomics. PLoS One 2023; 18:e0289070. [PMID: 37611017 PMCID: PMC10446203 DOI: 10.1371/journal.pone.0289070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 07/10/2023] [Indexed: 08/25/2023] Open
Abstract
Salmonella enterica serovar Typhi (S. Typhi) causes typhoid fever and, in some cases, chronic carriage after resolution of acute disease. This study examined sequential isolates of S. Typhi from a single host with persistent asymptomatic infection. These isolates, along with another S. Typhi isolate recovered from a household contact with typhoid fever, were subjected to whole genome sequencing and analysis. In addition, direct sequencing of the bile fluid from the host with persistent infection was also performed. Comparative analysis of isolates revealed three sub-populations of S. Typhi with distinct genetic patterns. Metagenomic sequencing recognised only two of the three sub-populations within the bile fluid. The detection and investigation of insertion sequences IS10R and associated deletions complemented analysis of single nucleotide polymorphisms. These findings improve our understanding of within-host dynamics of S. Typhi in cases of persistent infection and inform epidemiological investigations of transmission events associated with chronic carriers.
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Affiliation(s)
- Eby M. Sim
- Sydney Institute for Infectious Diseases, The University of Sydney, Westmead, New South Wales, Australia
- Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead, New South Wales, Australia
- Centre for Infectious Diseases and Microbiology- Public Health, Westmead Hospital, Westmead, New South Wales, Australia
| | - Qinning Wang
- Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead, New South Wales, Australia
| | - Peter Howard
- Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead, New South Wales, Australia
| | - Rady Kim
- Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead, New South Wales, Australia
| | - Ling Lim
- Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead, New South Wales, Australia
| | - Kirsty Hope
- Health Protection, New South Wales Ministry of Health, North Sydney, New South Wales, Australia
| | - Vitali Sintchenko
- Sydney Institute for Infectious Diseases, The University of Sydney, Westmead, New South Wales, Australia
- Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead, New South Wales, Australia
- Centre for Infectious Diseases and Microbiology- Public Health, Westmead Hospital, Westmead, New South Wales, Australia
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3
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Lipszyc A, Szuplewska M, Bartosik D. How Do Transposable Elements Activate Expression of Transcriptionally Silent Antibiotic Resistance Genes? Int J Mol Sci 2022; 23:8063. [PMID: 35897639 PMCID: PMC9330008 DOI: 10.3390/ijms23158063] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 07/17/2022] [Accepted: 07/20/2022] [Indexed: 02/06/2023] Open
Abstract
The rapidly emerging phenomenon of antibiotic resistance threatens to substantially reduce the efficacy of available antibacterial therapies. Dissemination of resistance, even between phylogenetically distant bacterial species, is mediated mainly by mobile genetic elements, considered to be natural vectors of horizontal gene transfer. Transposable elements (TEs) play a major role in this process-due to their highly recombinogenic nature they can mobilize adjacent genes and can introduce them into the pool of mobile DNA. Studies investigating this phenomenon usually focus on the genetic load of transposons and the molecular basis of their mobility. However, genes introduced into evolutionarily distant hosts are not necessarily expressed. As a result, bacterial genomes contain a reservoir of transcriptionally silent genetic information that can be activated by various transposon-related recombination events. The TEs themselves along with processes associated with their transposition can introduce promoters into random genomic locations. Thus, similarly to integrons, they have the potential to convert dormant genes into fully functional antibiotic resistance determinants. In this review, we describe the genetic basis of such events and by extension the mechanisms promoting the emergence of new drug-resistant bacterial strains.
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Affiliation(s)
| | | | - Dariusz Bartosik
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland; (A.L.); (M.S.)
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Yue Y, Puniya BL, Helikar T, Girardo B, Hinrichs SH, Larson MA. Arginine Catabolism and Polyamine Biosynthesis Pathway Disparities Within Francisella tularensis Subpopulations. Front Microbiol 2022; 13:890856. [PMID: 35794913 PMCID: PMC9251427 DOI: 10.3389/fmicb.2022.890856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 05/27/2022] [Indexed: 11/13/2022] Open
Abstract
Francisella tularensis is a highly infectious zoonotic pathogen with as few as 10 organisms causing tularemia, a disease that is fatal if untreated. Although F. tularensis subspecies tularensis (type A) and subspecies holarctica (type B) share over 99.5% average nucleotide identity, notable differences exist in genomic organization and pathogenicity. The type A clade has been further divided into subtypes A.I and A.II, with A.I strains being recognized as some of the most virulent bacterial pathogens known. In this study, we report on major disparities that exist between the F. tularensis subpopulations in arginine catabolism and subsequent polyamine biosynthesis. The genes involved in these pathways include the speHEA and aguAB operons, along with metK. In the hypervirulent F. tularensis A.I clade, such as the A.I prototype strain SCHU S4, these genes were found to be intact and highly transcribed. In contrast, both subtype A.II and type B strains have a truncated speA gene, while the type B clade also has a disrupted aguA and truncated aguB. Ablation of the chromosomal speE gene that encodes a spermidine synthase reduced subtype A.I SCHU S4 growth rate, whereas the growth rate of type B LVS was enhanced. These results demonstrate that spermine synthase SpeE promotes faster replication in the F. tularensis A.I clade, whereas type B strains do not rely on this enzyme for in vitro fitness. Our ongoing studies on amino acid and polyamine flux within hypervirulent A.I strains should provide a better understanding of the factors that contribute to F. tularensis pathogenicity.
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Affiliation(s)
- Yinshi Yue
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Bhanwar Lal Puniya
- Department of Biochemistry, University of Nebraska–Lincoln, Lincoln, NE, United States
| | - Tomáš Helikar
- Department of Biochemistry, University of Nebraska–Lincoln, Lincoln, NE, United States
| | - Benjamin Girardo
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Steven H. Hinrichs
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Marilynn A. Larson
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
- *Correspondence: Marilynn A. Larson,
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Brkljacic J, Wittler B, Lindsey BE, Ganeshan VD, Sovic MG, Niehaus J, Ajibola W, Bachle SM, Fehér T, Somers DE. Frequency, composition and mobility of Escherichia coli-derived transposable elements in holdings of plasmid repositories. Microb Biotechnol 2022; 15:455-468. [PMID: 34875147 PMCID: PMC8867978 DOI: 10.1111/1751-7915.13962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 10/14/2021] [Accepted: 10/19/2021] [Indexed: 11/29/2022] Open
Abstract
By providing the scientific community with uniform and standardized resources of consistent quality, plasmid repositories play an important role in enabling scientific reproducibility. Plasmids containing insertion sequence elements (IS elements) represent a challenge from this perspective, as they can change the plasmid structure and function. In this study, we conducted a systematic analysis of a subset of plasmid stocks distributed by plasmid repositories (The Arabidopsis Biological Resource Center and Addgene) which carry unintended integrations of bacterial mobile genetic elements. The integration of insertion sequences was most often found in, but not limited to, pBR322-derived vectors, and did not affect the function of the specific plasmids. In certain cases, the entire stock was affected, but the majority of the stocks tested contained a mixture of the wild-type and the mutated plasmids, suggesting that the acquisition of IS elements likely occurred after the plasmids were acquired by the repositories. However, comparison of the sequencing results of the original samples revealed that some plasmids already carried insertion mutations at the time of donation. While an extensive BLAST analysis of 47 877 plasmids sequenced from the Addgene repository uncovered IS elements in only 1.12%, suggesting that IS contamination is not widespread, further tests showed that plasmid integration of IS elements can propagate in conventional Escherichia coli hosts over a few tens of generations. Use of IS-free E. coli hosts prevented the emergence of IS insertions as well as that of small indels, suggesting that the use of IS-free hosts by donors and repositories could help limit unexpected and unwanted IS integrations into plasmids.
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Affiliation(s)
| | - Bettina Wittler
- Arabidopsis Biological Resource CenterColumbusOHUSA
- Present address:
Department of Molecular BiologyPrinceton UniversityPrincetonNJUSA
| | | | | | - Michael G. Sovic
- Center For Applied Plant SciencesThe Ohio State UniversityColumbusOHUSA
| | | | - Walliyulahi Ajibola
- Systems and Synthetic Biology UnitInstitute of BiochemistryBiological Research Centre of the Eötvös Lóránd Research NetworkSzegedHungary
- Doctoral School in BiologyUniversity of SzegedSzegedHungary
| | | | - Tamás Fehér
- Systems and Synthetic Biology UnitInstitute of BiochemistryBiological Research Centre of the Eötvös Lóránd Research NetworkSzegedHungary
| | - David E. Somers
- Arabidopsis Biological Resource CenterColumbusOHUSA
- Center For Applied Plant SciencesThe Ohio State UniversityColumbusOHUSA
- Department of Molecular GeneticsThe Ohio State UniversityColumbusOHUSA
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Jiang J, Wang W, Sun F, Zhang Y, Liu Q, Yang D. Bacterial infection reinforces host metabolic flux from arginine to spermine for NLRP3 inflammasome evasion. Cell Rep 2021; 34:108832. [PMID: 33691113 DOI: 10.1016/j.celrep.2021.108832] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 01/11/2021] [Accepted: 02/16/2021] [Indexed: 11/27/2022] Open
Abstract
Hosts recognize cytosolic microbial infection via the nucleotide-binding domain-like receptor (NLR) protein family, triggering inflammasome complex assembly to provoke pyroptosis or cytokine-related caspase-1-dependent antimicrobial responses. Pathogens have evolved diverse strategies to antagonize inflammasome activation. Here, Edwardsiella piscicida gene-defined transposon library screening for lactate dehydrogenase (LDH) release in nlrc4-/- bone marrow-derived macrophages (BMDMs) demonstrates that genes clustered in the bacterial arginine metabolism pathway participate in NLRP3 inflammasome inhibition. Blocking arginine uptake or putrescine export significantly relieves NLRP3 inflammasome inhibition, indicating that this bacterium rewires its arginine metabolism network during infection. Moreover, intracellular E. piscicida recruits the host arginine importer (mCAT-1) and putrescine exporter (Oct-2) to bacterium-containing vacuoles, accompanied by reduced arginine and accumulated cytosolic spermine. Neutralizing E. piscicida-induced cytosolic spermine enhancement by spermine synthetase or extracellular spermine significantly alters NLRP3 inflammasome activation. Importantly, accumulated cytosolic spermine inhibits K+ efflux-dependent NLRP3 inflammasome activation. These data highlight the mechanism of bacterial gene-mediated arginine metabolism control for NLRP3 inflammasome evasion.
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Affiliation(s)
- Jiatiao Jiang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Wenwen Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Fei Sun
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Yuanxing Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China
| | - Qin Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai 200237, China
| | - Dahai Yang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China; Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai 200237, China.
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7
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Structural and functional analysis of the Francisella lysine decarboxylase as a key actor in oxidative stress resistance. Sci Rep 2021; 11:972. [PMID: 33441661 PMCID: PMC7806604 DOI: 10.1038/s41598-020-79611-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 12/07/2020] [Indexed: 01/29/2023] Open
Abstract
Francisella tularensis is one of the most virulent pathogenic bacteria causing the acute human respiratory disease tularemia. While the mechanisms underlying F. tularensis pathogenesis are largely unknown, previous studies have shown that a F. novicida transposon mutant with insertions in a gene coding for a putative lysine decarboxylase was attenuated in mouse spleen, suggesting a possible role of its protein product as a virulence factor. Therefore, we set out to structurally and functionally characterize the F. novicida lysine decarboxylase, which we termed LdcF. Here, we investigate the genetic environment of ldcF as well as its evolutionary relationships with other basic AAT-fold amino acid decarboxylase superfamily members, known as key actors in bacterial adaptative stress response and polyamine biosynthesis. We determine the crystal structure of LdcF and compare it with the most thoroughly studied lysine decarboxylase, E. coli LdcI. We analyze the influence of ldcF deletion on bacterial growth under different stress conditions in dedicated growth media, as well as in infected macrophages, and demonstrate its involvement in oxidative stress resistance. Finally, our mass spectrometry-based quantitative proteomic analysis enables identification of 80 proteins with expression levels significantly affected by ldcF deletion, including several DNA repair proteins potentially involved in the diminished capacity of the F. novicida mutant to deal with oxidative stress. Taken together, we uncover an important role of LdcF in F. novicida survival in host cells through participation in oxidative stress response, thereby singling out this previously uncharacterized protein as a potential drug target.
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Control of Francisella tularensis Virulence at Gene Level: Network of Transcription Factors. Microorganisms 2020; 8:microorganisms8101622. [PMID: 33096715 PMCID: PMC7588896 DOI: 10.3390/microorganisms8101622] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/14/2020] [Accepted: 10/18/2020] [Indexed: 02/07/2023] Open
Abstract
Regulation of gene transcription is the initial step in the complex process that controls gene expression within bacteria. Transcriptional control involves the joint effort of RNA polymerases and numerous other regulatory factors. Whether global or local, positive or negative, regulators play an essential role in the bacterial cell. For instance, some regulators specifically modify the transcription of virulence genes, thereby being indispensable to pathogenic bacteria. Here, we provide a comprehensive overview of important transcription factors and DNA-binding proteins described for the virulent bacterium Francisella tularensis, the causative agent of tularemia. This is an unexplored research area, and the poorly described networks of transcription factors merit additional experimental studies to help elucidate the molecular mechanisms of pathogenesis in this bacterium, and how they contribute to disease.
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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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Nau GJ, Horzempa J, O’Dee D, Brown MJ, Russo BC, Hernandez A, Dillon ST, Cheng J, Kane LP, Sanker S, Hukriede NA. A predicted Francisella tularensis DXD-motif glycosyltransferase blocks immune activation. Virulence 2019; 10:643-656. [PMID: 31314675 PMCID: PMC6650193 DOI: 10.1080/21505594.2019.1631662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 06/07/2019] [Indexed: 02/04/2023] Open
Abstract
Pathogens enhance their survival during infections by manipulating host defenses. Francisella tularensis evades innate immune responses, which we have found to be dependent on an understudied gene ybeX (FTL_0883/FTT_0615c). To understand the function of YbeX, we sought protein interactors in F. tularensis subsp. holarctica live vaccine strain (LVS). An unstudied Francisella protein co-immunoprecipitated with recombinant YbeX, which is a predicted glycosyltransferase with a DXD-motif. There are up to four genomic copies of this gene with identical sequence in strains of F. tularensis pathogenic to humans, despite ongoing genome decay. Disruption mutations were generated by intron insertion into all three copies of this glycosyltransferase domain containing gene in LVS, gdcA1-3. The resulting strains stimulated more cytokines from macrophages in vitro than wild-type LVS and were attenuated in two in vivo infection models. GdcA was released from LVS during culture and was sufficient to block NF-κB activation when expressed in eukaryotic cells. When co-expressed in zebrafish, GdcA and YbeX were synergistically lethal to embryo development. Glycosyltransferases with DXD-motifs are found in a variety of pathogens including NleB, an Escherichia coli type-III secretion system effector that inhibits NF-κB by antagonizing death receptor signaling. To our knowledge, GdcA is the first DXD-motif glycosyltransferase that inhibits NF-κB in immune cells. Together, these findings suggest DXD-motif glycosyltransferases may be a conserved virulence mechanism used by pathogenic bacteria to remodel host defenses.
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Affiliation(s)
- Gerard J. Nau
- Division of Infectious Diseases, Alpert Medical School of Brown University, Providence, RI, USA
| | - Joseph Horzempa
- Department of Natural Sciences and Mathematics, West Liberty University, West Liberty, WV, USA
| | - Dawn O’Dee
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Matthew J. Brown
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Brian C. Russo
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Ana Hernandez
- Division of Infectious Diseases, Alpert Medical School of Brown University, Providence, RI, USA
| | - Simon T. Dillon
- Beth Israel Deaconess Medical Center Genomics, Proteomics, and Systems Biology Center, Harvard Medical School, Boston, MA, USA
| | - Jing Cheng
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Lawrence P. Kane
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Subramaniam Sanker
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Neil A. Hukriede
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Center for Critical Care Nephrology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Necroptotic debris including damaged mitochondria elicits sepsis-like syndrome during late-phase tularemia. Cell Death Discov 2017; 3:17056. [PMID: 28955505 PMCID: PMC5611684 DOI: 10.1038/cddiscovery.2017.56] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/30/2017] [Accepted: 07/18/2017] [Indexed: 12/31/2022] Open
Abstract
Infection with Francisella tularensis ssp. tularensis (Ft) strain SchuS4 causes an often lethal disease known as tularemia in rodents, non-human primates, and humans. Ft subverts host cell death programs to facilitate their exponential replication within macrophages and other cell types during early respiratory infection (⩽72 h). The mechanism(s) by which cell death is triggered remains incompletely defined, as does the impact of Ft on mitochondria, the host cell’s organellar ‘canary in a coal mine’. Herein, we reveal that Ft infection of host cells, particularly macrophages and polymorphonuclear leukocytes, drives necroptosis via a receptor-interacting protein kinase 1/3-mediated mechanism. During necroptosis mitochondria and other organelles become damaged. Ft-induced mitochondrial damage is characterized by: (i) a decrease in membrane potential and consequent mitochondrial oncosis or swelling, (ii) increased generation of superoxide radicals, and (iii) release of intact or damaged mitochondria into the lung parenchyma. Host cell recognition of and response to released mitochondria and other damage-associated molecular patterns engenders a sepsis-like syndrome typified by production of TNF, IL-1β, IL-6, IL-12p70, and IFN-γ during late-phase tularemia (⩾72 h), but are absent early during infection.
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12
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Complement C3 as a Prompt for Human Macrophage Death during Infection with Francisella tularensis Strain SCHU S4. Infect Immun 2017; 85:IAI.00424-17. [PMID: 28739830 DOI: 10.1128/iai.00424-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 07/18/2017] [Indexed: 02/06/2023] Open
Abstract
Tularemia is caused by the Gram-negative bacterial pathogen Francisella tularensis Infection of macrophages and their subsequent death are believed to play important roles in the progression of disease. Because complement is a particularly effective opsonin for Francisella, we asked whether complement-dependent uptake of F. tularensis strain SCHU S4 affects the survival of primary human macrophages during infection. Complement component C3 was found to be an essential opsonin in human serum not only for greatly increased uptake of SCHU S4 but also for the induction of macrophage death. Single-cell analysis also revealed that macrophage death did not require a high intracellular bacterial burden. In the presence of C3, macrophage death was observed at 24 h postinfection in a quarter of the macrophages that contained only 1 to 5 bacterial cells. Macrophages infected in the absence of C3 rarely underwent cell death, even when they contained large numbers of bacteria. The need for C3, but not extensive replication of the pathogen, was confirmed by infections with SCHU S4 ΔpurMCD, a mutant capable of phagosome escape but of only limited cytosolic replication. C3-dependent Francisella uptake alone was insufficient to induce macrophage death, as evidenced by the failure of the phagosome escape-deficient mutant SCHU S4 ΔfevR to induce cell death despite opsonization with C3. Together, these findings indicate that recognition of C3-opsonized F. tularensis, but not extensive cytosolic replication, plays an important role in regulating macrophage viability during intracellular infections with type A F. tularensis.
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13
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Freudenberger Catanzaro KC, Champion AE, Mohapatra N, Cecere T, Inzana TJ. Glycosylation of a Capsule-Like Complex (CLC) by Francisella novicida Is Required for Virulence and Partial Protective Immunity in Mice. Front Microbiol 2017; 8:935. [PMID: 28611741 PMCID: PMC5447757 DOI: 10.3389/fmicb.2017.00935] [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: 01/11/2017] [Accepted: 05/09/2017] [Indexed: 01/11/2023] Open
Abstract
Francisella tularensis is a Gram-negative bacterium and the etiologic agent of tularemia. F. tularensis may appear encapsulated when examined by transmission electron microscopy (TEM), which is due to production of an extracellular capsule-like complex (CLC) when the bacterium is grown under specific environmental conditions. Deletion of two glycosylation genes in the live vaccine strain (LVS) results in loss of apparent CLC and attenuation of LVS in mice. In contrast, F. novicida, which is also highly virulent for mice, is reported to be non-encapsulated. However, the F. novicida genome contains a putative polysaccharide locus with homology to the CLC glycosylation locus in F. tularensis. Following daily subculture of F. novicida in Chamberlain's defined medium, an electron dense material surrounding F. novicida, similar to the F. tularensis CLC, was evident. Extraction with urea effectively removed the CLC, and compositional analysis indicated the extract contained galactose, glucose, mannose, and multiple proteins, similar to those found in the F. tularensis CLC. The same glycosylation genes deleted in LVS were targeted for deletion in F. novicida by allelic exchange using the same mutagenesis vector used for mutagenesis of LVS. In contrast, this mutation also resulted in the loss of five additional genes immediately upstream of the targeted mutation (all within the glycosylation locus), resulting in strain F. novicida Δ1212-1218. The subcultured mutant F. novicida Δ1212-1218 was CLC-deficient and the CLC contained significantly less carbohydrate than the subcultured parent strain. The mutant was severely attenuated in BALB/c mice inoculated intranasally, as determined by the lower number of F. novicida Δ1212-1218 recovered in tissues compared to the parent, and by clearance of the mutant by 10-14 days post-challenge. Mice immunized intranasally with F. novicida Δ1212-1218 were partially protected against challenge with the parent, produced significantly reduced levels of inflammatory cytokines, and their spleens contained only areas of lymphoid hyperplasia, whereas control mice challenged with the parent exhibited hypercytokinemia and splenic necrosis. Therefore, F. novicida is capable of producing a CLC similar to that of F. tularensis, and glycosylation of the CLC contributed to F. novicida virulence and immunoprotection.
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Affiliation(s)
- Kelly C Freudenberger Catanzaro
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland College of Veterinary Medicine, Virginia TechBlacksburg, VA, United States
| | - Anna E Champion
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland College of Veterinary Medicine, Virginia TechBlacksburg, VA, United States
| | - Nrusingh Mohapatra
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland College of Veterinary Medicine, Virginia TechBlacksburg, VA, United States
| | - Thomas Cecere
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland College of Veterinary Medicine, Virginia TechBlacksburg, VA, United States
| | - Thomas J Inzana
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland College of Veterinary Medicine, Virginia TechBlacksburg, VA, United States.,Department of Biomedical Sciences, Virginia Tech Carilion School of MedicineRoanoke, VA, United States
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14
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Vandecraen J, Chandler M, Aertsen A, Van Houdt R. The impact of insertion sequences on bacterial genome plasticity and adaptability. Crit Rev Microbiol 2017; 43:709-730. [PMID: 28407717 DOI: 10.1080/1040841x.2017.1303661] [Citation(s) in RCA: 234] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Transposable elements (TE), small mobile genetic elements unable to exist independently of the host genome, were initially believed to be exclusively deleterious genomic parasites. However, it is now clear that they play an important role as bacterial mutagenic agents, enabling the host to adapt to new environmental challenges and to colonize new niches. This review focuses on the impact of insertion sequences (IS), arguably the smallest TE, on bacterial genome plasticity and concomitant adaptability of phenotypic traits, including resistance to antibacterial agents, virulence, pathogenicity and catabolism. The direct consequence of IS transposition is the insertion of one DNA sequence into another. This event can result in gene inactivation as well as in modulation of neighbouring gene expression. The latter is usually mediated by de-repression or by the introduction of a complete or partial promoter located within the element. Furthermore, transcription and transposition of IS are affected by host factors and in some cases by environmental signals offering the host an adaptive strategy and promoting genetic variability to withstand the environmental challenges.
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Affiliation(s)
- Joachim Vandecraen
- a Microbiology Unit, Interdisciplinary Biosciences , Belgian Nuclear Research Centre (SCK•CEN) , Mol , Belgium.,b Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre , Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering , KU Leuven , Leuven , Belgium
| | - Michael Chandler
- c Laboratoire de Microbiologie et Génétique Moléculaires, Centre national de la recherche scientifique , Toulouse , France
| | - Abram Aertsen
- b Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre , Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering , KU Leuven , Leuven , Belgium
| | - Rob Van Houdt
- a Microbiology Unit, Interdisciplinary Biosciences , Belgian Nuclear Research Centre (SCK•CEN) , Mol , Belgium
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15
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Hotta A, Fujita O, Uda A, Yamamoto Y, Sharma N, Tanabayashi K, Yamada A, Morikawa S. Virulence of representative Japanese Francisella tularensis and immunologic consequences of infection in mice. Microbiol Immunol 2017; 60:168-76. [PMID: 26853540 DOI: 10.1111/1348-0421.12363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 01/19/2016] [Accepted: 02/02/2016] [Indexed: 11/28/2022]
Abstract
Francisella tularensis, which causes tularemia, is widely distributed in the Northern hemisphere. F. tularensis strains isolated in Japan are genetically unique from non-Japanese strains; however, their phenotypic properties have not been well studied. Thus, mice were infected with representative Japanese strains of F. tularensis and their virulence and mouse immune responses to them assessed. Of four representative Japanese strains, the Ebina, Jap and Tsuchiya strains were susceptible to H2 O2 and did not grow well intracellularly. Only Yama strain grew intracellularly and was lethal to mice. Infection with Yama strain resulted in drastic increases in IFN-γ, CD4 and CD8 double-positive T cells and Th1 cells (CD3, CD4 and Tim3-positive cells), and a decrease in the ratio of CD8-positive CD4-negative T cells in mice. C57BL/6J mice that survived infection produced IgM antibodies to LPS and IgG2c antibodies to 43, 19 and 17 kDa proteinase K-sensitive components. These data are valuable for understanding the phenotypic properties of F. tularensis in Japan.
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Affiliation(s)
- Akitoyo Hotta
- Department of Veterinary Science, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku, Tokyo 162-8640
| | - Osamu Fujita
- Department of Veterinary Science, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku, Tokyo 162-8640
| | - Akihiko Uda
- Department of Veterinary Science, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku, Tokyo 162-8640
| | - Yoshie Yamamoto
- Department of Veterinary Science, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku, Tokyo 162-8640
| | - Neekun Sharma
- Department of Veterinary Science, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku, Tokyo 162-8640.,United Graduate School of Veterinary Science Gifu University, 1-1 Yanagido, Gifu 501-1193
| | - Kiyoshi Tanabayashi
- Department of Veterinary Science, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku, Tokyo 162-8640
| | - Akio Yamada
- Laboratory of Veterinary Public Health, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan
| | - Shigeru Morikawa
- Department of Veterinary Science, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku, Tokyo 162-8640.,United Graduate School of Veterinary Science Gifu University, 1-1 Yanagido, Gifu 501-1193
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16
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Sarva ST, Waldo RH, Belland RJ, Klose KE. Comparative Transcriptional Analyses of Francisella tularensis and Francisella novicida. PLoS One 2016; 11:e0158631. [PMID: 27537327 PMCID: PMC4990168 DOI: 10.1371/journal.pone.0158631] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 06/20/2016] [Indexed: 01/18/2023] Open
Abstract
Francisella tularensis is composed of a number of subspecies with varied geographic distribution, host ranges, and virulence. In view of these marked differences, comparative functional genomics may elucidate some of the molecular mechanism(s) behind these differences. In this study a shared probe microarray was designed that could be used to compare the transcriptomes of Francisella tularensis subsp. tularensis Schu S4 (Ftt), Francisella tularensis subsp. holarctica OR960246 (Fth), Francisella tularensis subsp. holarctica LVS (LVS), and Francisella novicida U112 (Fn). To gain insight into expression differences that may be related to the differences in virulence of these subspecies, transcriptomes were measured from each strain grown in vitro under identical conditions, utilizing a shared probe microarray. The human avirulent Fn strain exhibited high levels of transcription of genes involved in general metabolism, which are pseudogenes in the human virulent Ftt and Fth strains, consistent with the process of genome decay in the virulent strains. Genes encoding an efflux system (emrA2 cluster of genes), siderophore (fsl operon), acid phosphatase, LPS synthesis, polyamine synthesis, and citrulline ureidase were all highly expressed in Ftt when compared to Fn, suggesting that some of these may contribute to the relative high virulence of Ftt. Genes expressed at a higher level in Ftt when compared to the relatively less virulent Fth included genes encoding isochorismatases, cholylglycine hydrolase, polyamine synthesis, citrulline ureidase, Type IV pilus subunit, and the Francisella Pathogenicity Island protein PdpD. Fth and LVS had very few expression differences, consistent with the derivation of LVS from Fth. This study demonstrated that a shared probe microarray designed to detect transcripts in multiple species/subspecies of Francisella enabled comparative transcriptional analyses that may highlight critical differences that underlie the relative pathogenesis of these strains for humans. This strategy could be extended to other closely-related bacterial species for inter-strain and inter-species analyses.
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Affiliation(s)
- Siva T. Sarva
- University of Tennessee Health Science Center, Memphis, TN, United States of America
| | - Robert H. Waldo
- University of Tennessee Health Science Center, Memphis, TN, United States of America
| | - Robert J. Belland
- University of Tennessee Health Science Center, Memphis, TN, United States of America
| | - Karl E. Klose
- South Texas Center for Emerging Infectious Diseases and Dept. of Biology, University of Texas San Antonio, San Antonio, TX, United States of America
- * E-mail:
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17
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Vandecraen J, Monsieurs P, Mergeay M, Leys N, Aertsen A, Van Houdt R. Zinc-Induced Transposition of Insertion Sequence Elements Contributes to Increased Adaptability of Cupriavidus metallidurans. Front Microbiol 2016; 7:359. [PMID: 27047473 PMCID: PMC4803752 DOI: 10.3389/fmicb.2016.00359] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 03/07/2016] [Indexed: 12/15/2022] Open
Abstract
Bacteria can respond to adverse environments by increasing their genomic variability and subsequently facilitating adaptive evolution. To demonstrate this, the contribution of Insertion Sequence (IS) elements to the genetic adaptation of Cupriavidus metallidurans AE126 to toxic zinc concentrations was determined. This derivative of type strain CH34, devoid of its main zinc resistance determinant, is still able to increase its zinc resistance level. Specifically, upon plating on medium supplemented with a toxic zinc concentration, resistant variants arose in which a compromised cnrYX regulatory locus caused derepression of CnrH sigma factor activity and concomitant induction of the corresponding RND-driven cnrCBA efflux system. Late-occurring zinc resistant variants likely arose in response to the selective conditions, as they were enriched in cnrYX disruptions caused by specific IS elements whose transposase expression was found to be zinc-responsive. Interestingly, deletion of cnrH, and consequently the CnrH-dependent adaptation potential, still enabled adaptation by transposition of IS elements (ISRme5 and IS1086) that provided outward-directed promoters driving cnrCBAT transcription. Finally, adaptation to zinc by IS reshuffling can also enhance the adaptation to subsequent environmental challenges. Thus, transposition of IS elements can be induced by stress conditions and play a multifaceted, pivotal role in the adaptation to these and subsequent stress conditions.
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Affiliation(s)
- Joachim Vandecraen
- Unit of Microbiology, Belgian Nuclear Research Centre (SCK•CEN)Mol, Belgium; Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, Katholieke Universiteit LeuvenLeuven, Belgium
| | - Pieter Monsieurs
- Unit of Microbiology, Belgian Nuclear Research Centre (SCK•CEN) Mol, Belgium
| | - Max Mergeay
- Unit of Microbiology, Belgian Nuclear Research Centre (SCK•CEN) Mol, Belgium
| | - Natalie Leys
- Unit of Microbiology, Belgian Nuclear Research Centre (SCK•CEN) Mol, Belgium
| | - Abram Aertsen
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, Katholieke Universiteit Leuven Leuven, Belgium
| | - Rob Van Houdt
- Unit of Microbiology, Belgian Nuclear Research Centre (SCK•CEN) Mol, Belgium
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18
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de Paiva JB, da Silva LPM, Casas MRT, Conceição RA, Nakazato G, de Pace F, Sperandio V, da Silveira WD. In vivoinfluence ofin vitroup-regulated genes in the virulence of an APEC strain associated with swollen head syndrome. Avian Pathol 2016; 45:94-105. [DOI: 10.1080/03079457.2015.1125995] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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19
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Carlson PE, Bourgis AET, Hagan AK, Hanna PC. Global gene expression by Bacillus anthracis during growth in mammalian blood. Pathog Dis 2015; 73:ftv061. [PMID: 26316554 DOI: 10.1093/femspd/ftv061] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2015] [Indexed: 01/03/2023] Open
Abstract
During the late stages of systemic anthrax, Bacillus anthracis grows rapidly in the host bloodstream. To identify potential genes necessary for this observed rapid growth, we defined the transcriptional profile of B. anthracis during in vitro growth in bovine blood. Genome-wide transcriptome analysis indicated that B. anthracis undergoes significant changes in its transcriptome profile during growth in blood, including the differential regulation of genes associated both with metabolism and known virulence factors. Collectively, these data provide a framework for future studies identifying specific B. anthracis factors required for growth in the mammalian bloodstream.
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Affiliation(s)
- Paul E Carlson
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48104, USA
| | - Alexandra E T Bourgis
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48104, USA
| | - Ada K Hagan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48104, USA
| | - Philip C Hanna
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48104, USA
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20
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Buck TM, Jordan R, Lyons-Weiler J, Adelman JL, Needham PG, Kleyman TR, Brodsky JL. Expression of three topologically distinct membrane proteins elicits unique stress response pathways in the yeast Saccharomyces cerevisiae. Physiol Genomics 2015; 47:198-214. [PMID: 25759377 DOI: 10.1152/physiolgenomics.00101.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 03/04/2015] [Indexed: 01/11/2023] Open
Abstract
Misfolded membrane proteins are retained in the endoplasmic reticulum (ER) and are subject to ER-associated degradation, which clears the secretory pathway of potentially toxic species. While the transcriptional response to environmental stressors has been extensively studied, limited data exist describing the cellular response to misfolded membrane proteins. To this end, we expressed and then compared the transcriptional profiles elicited by the synthesis of three ER retained, misfolded ion channels: The α-subunit of the epithelial sodium channel, ENaC, the cystic fibrosis transmembrane conductance regulator, CFTR, and an inwardly rectifying potassium channel, Kir2.1, which vary in their mass, membrane topologies, and quaternary structures. To examine transcriptional profiles in a null background, the proteins were expressed in yeast, which was previously used to examine the degradation requirements for each substrate. Surprisingly, the proteins failed to induce a canonical unfolded protein response or heat shock response, although messages encoding several cytosolic and ER lumenal protein folding factors rose when αENaC or CFTR was expressed. In contrast, the levels of these genes were unaltered by Kir2.1 expression; instead, the yeast iron regulon was activated. Nevertheless, a significant number of genes that respond to various environmental stressors were upregulated by all three substrates, and compared with previous microarray data we deduced the existence of a group of genes that reflect a novel misfolded membrane protein response. These data indicate that aberrant proteins in the ER elicit profound yet unique cellular responses.
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Affiliation(s)
- Teresa M Buck
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Rick Jordan
- GPCL Bioinformatics Analysis Core, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - James Lyons-Weiler
- GPCL Bioinformatics Analysis Core, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Joshua L Adelman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Patrick G Needham
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Thomas R Kleyman
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania;
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21
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Effects of norspermidine and spermidine on biofilm formation by potentially pathogenic Escherichia coli and Salmonella enterica wild-type strains. Appl Environ Microbiol 2015; 81:2226-32. [PMID: 25595767 DOI: 10.1128/aem.03518-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Polyamines are present in all living cells. In bacteria, polyamines are involved in a variety of functions, including biofilm formation, thus indicating that polyamines may have potential in the control of unwanted biofilm. In the present study, the effects of the polyamines norspermidine and spermidine on biofilms of 10 potentially pathogenic wild-type strains of Escherichia coli serotype O103:H2, Salmonella enterica subsp. enterica serovar Typhimurium, and S. enterica serovar Agona were investigated. We found that exogenously supplied norspermidine and spermidine did not mediate disassembly of preformed biofilm of any of the E. coli and S. enterica strains. However, the polyamines did affect biofilm production. Interestingly, the two species reacted differently to the polyamines. Both polyamines reduced the amount of biofilm formed by E. coli but tended to increase biofilm formation by S. enterica. Whether the effects observed were due to the polyamines specifically targeting biofilm formation, being toxic for the cells, or maybe a combination of the two, is not known. However, there were no indications that the effect was mediated through binding to exopolysaccharides, as earlier suggested for E. coli. Our results indicate that norspermidine and spermidine do not have potential as inhibitors of S. enterica biofilm. Furthermore, we found that the commercial polyamines used contributed to the higher pH of the test medium. Failure to acknowledge and control this important phenomenon may lead to misinterpretation of the results.
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22
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Polyamines are essential for virulence in Salmonella enterica serovar Gallinarum despite evolutionary decay of polyamine biosynthesis genes. Vet Microbiol 2014; 170:144-50. [PMID: 24602405 DOI: 10.1016/j.vetmic.2014.01.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 01/27/2014] [Accepted: 01/28/2014] [Indexed: 11/23/2022]
Abstract
Serovars of Salmonella enterica exhibit different host-specificities where some have broad host-ranges and others, like S. Gallinarum and S. Typhi, are host-specific for poultry and humans, respectively. With the recent availability of whole genome sequences it has been reported that host-specificity coincides with accumulation of pseudogenes, indicating adaptation of host-restricted serovars to their narrow niches. Polyamines are small cationic amines and in Salmonella they can be synthesized through two alternative pathways directly from l-ornithine to putrescine and from l-arginine via agmatine to putrescine. The first pathway is not active in S. Gallinarum and S. Typhi, and this prompted us to investigate the importance of polyamines for virulence in S. Gallinarum. Bioinformatic analysis of all sequenced genomes of Salmonella revealed that pseudogene formation of the speC gene was exclusive for S. Typhi and S. Gallinarum and happened through independent events. The remaining polyamine biosynthesis pathway was found to be essential for oral infection with S. Gallinarum since single and double mutants in speB and speE, encoding the pathways from agmatine to putrescine and from putrescine to spermidine, were attenuated. In contrast, speB was dispensable after intraperitoneal challenge, suggesting that putrescine was less important for the systemic phase of the disease. In support of this hypothesis, a ΔspeE;ΔpotCD mutant, unable to synthesize and import spermidine, but with retained ability to import and synthesize putrescine, was attenuated after intraperitoneal infection. We therefore conclude that polyamines are essential for virulence of S. Gallinarum. Furthermore, our results point to distinct roles for putrescine and spermidine during systemic infection.
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23
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Schmitt DM, O'Dee DM, Cowan BN, Birch JWM, Mazzella LK, Nau GJ, Horzempa J. The use of resazurin as a novel antimicrobial agent against Francisella tularensis. Front Cell Infect Microbiol 2013; 3:93. [PMID: 24367766 PMCID: PMC3853850 DOI: 10.3389/fcimb.2013.00093] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 11/20/2013] [Indexed: 11/13/2022] Open
Abstract
The highly infectious and deadly pathogen, Francisella tularensis, is classified by the CDC as a Category A bioterrorism agent. Inhalation of a single bacterium results in an acute pneumonia with a 30-60% mortality rate without treatment. Due to the prevalence of antibiotic resistance, there is a strong need for new types of antibacterial drugs. Resazurin is commonly used to measure bacterial and eukaryotic cell viability through its reduction to the fluorescent product resorufin. When tested on various bacterial taxa at the recommended concentration of 44 μM, a potent bactericidal effect was observed against various Francisella and Neisseria species, including the human pathogens type A F. tularensis (Schu S4) and N. gonorrhoeae. As low as 4.4 μM resazurin was sufficient for a 10-fold reduction in F. tularensis growth. In broth culture, resazurin was reduced to resorufin by F. tularensis. Resorufin also suppressed the growth of F. tularensis suggesting that this compound is the biologically active form responsible for decreasing the viability of F. tularensis LVS bacteria. Replication of F. tularensis in primary human macrophages and non-phagocytic cells was abolished following treatment with 44 μM resazurin indicating this compound could be an effective therapy for tularemia in vivo.
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Affiliation(s)
- Deanna M Schmitt
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
| | - Dawn M O'Dee
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine Pittsburgh, PA, USA
| | - Brianna N Cowan
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
| | - James W-M Birch
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
| | - Leanne K Mazzella
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
| | - Gerard J Nau
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine Pittsburgh, PA, USA ; Department of Medicine - Division of Infectious Diseases, University of Pittsburgh School of Medicine Pittsburgh, PA, USA ; Center for Vaccine Research, University of Pittsburgh School of Medicine Pittsburgh, PA, USA
| | - Joseph Horzempa
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
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24
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Di Martino ML, Campilongo R, Casalino M, Micheli G, Colonna B, Prosseda G. Polyamines: emerging players in bacteria-host interactions. Int J Med Microbiol 2013; 303:484-91. [PMID: 23871215 DOI: 10.1016/j.ijmm.2013.06.008] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 06/13/2013] [Accepted: 06/16/2013] [Indexed: 12/17/2022] Open
Abstract
Polyamines are small polycationic molecules found in almost all cells and associated with a wide variety of physiological processes. In recent years it has become increasingly clear that, in addition to core physiological functions, polyamines play a crucial role in bacterial pathogenesis. Considerable evidence has built up that bacteria have evolved mechanisms to turn these molecules to their own advantage and a novel standpoint to look at host-bacterium interactions emerges from the interplay among polyamines, host cells and infecting bacteria. In this review, we highlight how human bacterial pathogens have developed their own resourceful strategies to exploit polyamines or manipulate polyamine-related processes to optimize their fitness within the host. Besides contributing to a better understanding of the complex relationship between a pathogen and its host, acquisitions in this field have a significant potential towards the development of novel antibacterial therapeutic approaches.
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Affiliation(s)
- Maria Letizia Di Martino
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Via dei Sardi 70, 00185 Roma, Italy; Dipartimento di Biologia, Università Roma Tre, Viale G. Marconi 446, 00146 Roma, Italy
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25
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Singh A, Rahman T, Malik M, Hickey AJ, Leifer CA, Hazlett KRO, Sellati TJ. Discordant results obtained with Francisella tularensis during in vitro and in vivo immunological studies are attributable to compromised bacterial structural integrity. PLoS One 2013; 8:e58513. [PMID: 23554897 PMCID: PMC3595284 DOI: 10.1371/journal.pone.0058513] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 02/05/2013] [Indexed: 11/18/2022] Open
Abstract
Francisella tularensis (Ft) is a highly infectious intracellular pathogen and the causative agent of tularemia. Because Ft can be dispersed via small droplet-aerosols and has a very low infectious dose it is characterized as a category A Select Agent of biological warfare. Respiratory infection with the attenuated Live Vaccine Strain (LVS) and the highly virulent SchuS4 strain of Ft engenders intense peribronchiolar and perivascular inflammation, but fails to elicit select pro-inflammatory mediators (e.g., TNF, IL-1β, IL-6, IL-12, and IFN-γ) within the first ∼72 h. This in vivo finding is discordant with the principally TH1-oriented response to Ft frequently observed in cell-based studies wherein the aforementioned cytokines are produced. An often overlooked confounding factor in the interpretation of experimental results is the influence of environmental cues on the bacterium's capacity to elicit certain host responses. Herein, we reveal that adaptation of Ft to its mammalian host imparts an inability to elicit select pro-inflammatory mediators throughout the course of infection. Furthermore, in vitro findings that non-host adapted Ft elicits such a response from host cells reflect aberrant recognition of the DNA of structurally-compromised bacteria by AIM2-dependent and -independent host cell cytosolic DNA sensors. Growth of Ft in Muller-Hinton Broth or on Muller-Hinton-based chocolate agar plates or genetic mutation of Ft was found to compromise the structural integrity of the bacterium thus rendering it capable of aberrantly eliciting pro-inflammatory mediators (e.g., TNF, IL-1β, IL-6, IL-12, and IFN-γ). Our studies highlight the profound impact of different growth conditions on host cell response to infection and demonstrate that not all in vitro-derived findings may be relevant to tularemia pathogenesis in the mammalian host. Rational development of a vaccine and immunotherapeutics can only proceed from a foundation of knowledge based upon in vitro findings that recapitulate those observed during natural infection.
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Affiliation(s)
- Anju Singh
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
| | - Tabassum Rahman
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
| | - Meenakshi Malik
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
| | - Anthony J. Hickey
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
| | - Cynthia A. Leifer
- Department of Microbiology and Immunology, Cornell University College of Veterinary Medicine, Ithaca, New York, United States of America
| | - Karsten R. O. Hazlett
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
| | - Timothy J. Sellati
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
- * E-mail:
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Role of NK cells in host defense against pulmonary type A Francisella tularensis infection. Microbes Infect 2012; 15:201-11. [PMID: 23211929 DOI: 10.1016/j.micinf.2012.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 10/25/2012] [Accepted: 11/15/2012] [Indexed: 01/16/2023]
Abstract
Pneumonic tularemia is a potentially fatal disease caused by the Category A bioterrorism agent Francisella tularensis. Understanding the pulmonary immune response to this bacterium is necessary for developing effective vaccines and therapeutics. In this study, characterization of immune cell populations in the lungs of mice infected with the type A strain Schu S4 revealed a significant loss in natural killer (NK) cells over time. Since this decline in NK cells correlated with morbidity and mortality, we hypothesized these cells contribute to host defense against Schu S4 infection. Depletion of NK cells prior to Schu S4 challenge significantly reduced IFN-γ and granzyme B in the lung but had no effect on bacterial burden or disease progression. Conversely, increasing NK cell numbers with the anti-apoptotic cytokine IL-15 and soluble receptor IL-15Rα had no significant impact on Schu S4 growth in vivo. A modest decrease in median time to death, however, was observed in live vaccine strain (LVS)-vaccinated mice depleted of NK1.1+ cells and challenged with Schu S4. Therefore, NK cells do not appear to contribute to host defense against acute respiratory infection with type A F. tularensis in vivo, but they play a minor role in protection elicited by LVS vaccination.
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Subversion of host recognition and defense systems by Francisella spp. Microbiol Mol Biol Rev 2012; 76:383-404. [PMID: 22688817 DOI: 10.1128/mmbr.05027-11] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Francisella tularensis is a gram-negative intracellular pathogen and the causative agent of the disease tularemia. Inhalation of as few as 10 bacteria is sufficient to cause severe disease, making F. tularensis one of the most highly virulent bacterial pathogens. The initial stage of infection is characterized by the "silent" replication of bacteria in the absence of a significant inflammatory response. Francisella achieves this difficult task using several strategies: (i) strong integrity of the bacterial surface to resist host killing mechanisms and the release of inflammatory bacterial components (pathogen-associated molecular patterns [PAMPs]), (ii) modification of PAMPs to prevent activation of inflammatory pathways, and (iii) active modulation of the host response by escaping the phagosome and directly suppressing inflammatory pathways. We review the specific mechanisms by which Francisella achieves these goals to subvert host defenses and promote pathogenesis, highlighting as-yet-unanswered questions and important areas for future study.
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Jelsbak L, Thomsen LE, Wallrodt I, Jensen PR, Olsen JE. Polyamines are required for virulence in Salmonella enterica serovar Typhimurium. PLoS One 2012; 7:e36149. [PMID: 22558361 PMCID: PMC3340349 DOI: 10.1371/journal.pone.0036149] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 03/27/2012] [Indexed: 11/18/2022] Open
Abstract
Sensing and responding to environmental cues is a fundamental characteristic of bacterial physiology and virulence. Here we identify polyamines as novel environmental signals essential for virulence of Salmonella enterica serovar Typhimurium, a major intracellular pathogen and a model organism for studying typhoid fever. Central to its virulence are two major virulence loci Salmonella Pathogenicity Island 1 and 2 (SPI1 and SPI2). SPI1 promotes invasion of epithelial cells, whereas SPI2 enables S. Typhimurium to survive and proliferate within specialized compartments inside host cells. In this study, we show that an S. Typhimurium polyamine mutant is defective for invasion, intracellular survival, killing of the nematode Caenorhabditis elegans and systemic infection of the mouse model of typhoid fever. Virulence of the mutant could be restored by genetic complementation, and invasion and intracellular survival could, as well, be complemented by the addition of exogenous putrescine and spermidine to the bacterial cultures prior to infection. Interestingly, intracellular survival of the polyamine mutant was significantly enhanced above the wild type level by the addition of exogenous putrescine and spermidine to the bacterial cultures prior to infection, indicating that these polyamines function as an environmental signal that primes S. Typhimurium for intracellular survival. Accordingly, experiments addressed at elucidating the roles of these polyamines in infection revealed that expression of genes from both of the major virulence loci SPI1 and SPI2 responded to exogenous polyamines and was reduced in the polyamine mutant. Together our data demonstrate that putrescine and spermidine play a critical role in controlling virulence in S. Typhimurium most likely through stimulation of expression of essential virulence loci. Moreover, our data implicate these polyamines as key signals in S. Typhimurium virulence.
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Affiliation(s)
- Lotte Jelsbak
- Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark.
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Mafra DG, da Silva PI, Galhardo CS, Nassar R, Daffre S, Sato MN, Borges MM. The spider acylpolyamine Mygalin is a potent modulator of innate immune responses. Cell Immunol 2012; 275:5-11. [PMID: 22541370 DOI: 10.1016/j.cellimm.2012.04.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 02/21/2012] [Accepted: 04/01/2012] [Indexed: 01/18/2023]
Abstract
Mygalin is an antibacterial molecule isolated from the hemocytes of the spider Acanthoscurria gomesiana. It was identified as bis-acylpolyamine spermidine. We evaluated the modulator effects of synthetic Mygalin in the innate immune response. We demonstrate that Mygalin induces IFN-γ synthesis by splenocytes increasing the nitrite secretion by splenocytes and macrophages. A specific inhibitor of iNOS abrogated Mygalin-induced nitrite production in macrophages independent of IFN-γ activation. In addition, Mygalin-activated macrophages produced TNF-α but not IL-1β, demonstrating that Mygalin does not act directly on the inflammasome. Furthermore, this compound did not affect spontaneous or Concanavalin A-induced proliferative responses by murine splenocytes and did not induce IL-5 or apoptosis of splenocytes or bone marrow-derived macrophages. These data provide evidence that Mygalin modulates the innate immune response by inducing IFN-γ and NO synthesis. The combined immune regulatory and antibacterial qualities of Mygalin should be explored as a strategy to enhance immune responses in infection.
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Schmitt DM, O'Dee DM, Horzempa J, Carlson PE, Russo BC, Bales JM, Brown MJ, Nau GJ. A Francisella tularensis live vaccine strain that improves stimulation of antigen-presenting cells does not enhance vaccine efficacy. PLoS One 2012; 7:e31172. [PMID: 22355343 PMCID: PMC3280287 DOI: 10.1371/journal.pone.0031172] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Accepted: 01/04/2012] [Indexed: 11/25/2022] Open
Abstract
Vaccination is a proven strategy to mitigate morbidity and mortality of infectious diseases. The methodology of identifying and testing new vaccine candidates could be improved with rational design and in vitro testing prior to animal experimentation. The tularemia vaccine, Francisella tularensis live vaccine strain (LVS), does not elicit complete protection against lethal challenge with a virulent type A Francisella strain. One factor that may contribute to this poor performance is limited stimulation of antigen-presenting cells. In this study, we examined whether the interaction of genetically modified LVS strains with human antigen-presenting cells correlated with effectiveness as tularemia vaccine candidates. Human dendritic cells infected with wild-type LVS secrete low levels of proinflammatory cytokines, fail to upregulate costimulatory molecules, and activate human T cells poorly in vitro. One LVS mutant, strain 13B47, stimulated higher levels of proinflammatory cytokines from dendritic cells and macrophages and increased costimulatory molecule expression on dendritic cells compared to wild type. Additionally, 13B47-infected dendritic cells activated T cells more efficiently than LVS-infected cells. A deletion allele of the same gene in LVS displayed similar in vitro characteristics, but vaccination with this strain did not improve survival after challenge with a virulent Francisella strain. In vivo, this mutant was attenuated for growth and did not stimulate T cell responses in the lung comparable to wild type. Therefore, stimulation of antigen-presenting cells in vitro was improved by genetic modification of LVS, but did not correlate with efficacy against challenge in vivo within this model system.
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Affiliation(s)
- Deanna M. Schmitt
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Dawn M. O'Dee
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Joseph Horzempa
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Department of Natural Sciences and Mathematics, West Liberty University, West Liberty, West Virginia, United States of America
| | - Paul E. Carlson
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Brian C. Russo
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Jacqueline M. Bales
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Matthew J. Brown
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Gerard J. Nau
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Department of Medicine – Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Center for Vaccine Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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Schmitz-Esser S, Penz T, Spang A, Horn M. A bacterial genome in transition--an exceptional enrichment of IS elements but lack of evidence for recent transposition in the symbiont Amoebophilus asiaticus. BMC Evol Biol 2011; 11:270. [PMID: 21943072 PMCID: PMC3196728 DOI: 10.1186/1471-2148-11-270] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 09/26/2011] [Indexed: 11/18/2022] Open
Abstract
Background Insertion sequence (IS) elements are important mediators of genome plasticity and are widespread among bacterial and archaeal genomes. The 1.88 Mbp genome of the obligate intracellular amoeba symbiont Amoebophilus asiaticus contains an unusually large number of transposase genes (n = 354; 23% of all genes). Results The transposase genes in the A. asiaticus genome can be assigned to 16 different IS elements termed ISCaa1 to ISCaa16, which are represented by 2 to 24 full-length copies, respectively. Despite this high IS element load, the A. asiaticus genome displays a GC skew pattern typical for most bacterial genomes, indicating that no major rearrangements have occurred recently. Additionally, the high sequence divergence of some IS elements, the high number of truncated IS element copies (n = 143), as well as the absence of direct repeats in most IS elements suggest that the IS elements of A. asiaticus are transpositionally inactive. Although we could show transcription of 13 IS elements, we did not find experimental evidence for transpositional activity, corroborating our results from sequence analyses. However, we detected contiguous transcripts between IS elements and their downstream genes at nine loci in the A. asiaticus genome, indicating that some IS elements influence the transcription of downstream genes, some of which might be important for host cell interaction. Conclusions Taken together, the IS elements in the A. asiaticus genome are currently in the process of degradation and largely represent reflections of the evolutionary past of A. asiaticus in which its genome was shaped by their activity.
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Affiliation(s)
- Stephan Schmitz-Esser
- Department of Microbial Ecology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
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Zarrella TM, Singh A, Bitsaktsis C, Rahman T, Sahay B, Feustel PJ, Gosselin EJ, Sellati TJ, Hazlett KRO. Host-adaptation of Francisella tularensis alters the bacterium's surface-carbohydrates to hinder effectors of innate and adaptive immunity. PLoS One 2011; 6:e22335. [PMID: 21799828 PMCID: PMC3142145 DOI: 10.1371/journal.pone.0022335] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 06/27/2011] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The gram-negative bacterium Francisella tularensis survives in arthropods, fresh water amoeba, and mammals with both intracellular and extracellular phases and could reasonably be expected to express distinct phenotypes in these environments. The presence of a capsule on this bacterium has been controversial with some groups finding such a structure while other groups report that no capsule could be identified. Previously we reported in vitro culture conditions for this bacterium which, in contrast to typical methods, yielded a bacterial phenotype that mimics that of the bacterium's mammalian, extracellular phase. METHODS/FINDINGS SDS-PAGE and carbohydrate analysis of differentially-cultivated F. tularensis LVS revealed that bacteria displaying the host-adapted phenotype produce both longer polymers of LPS O-antigen (OAg) and additional HMW carbohydrates/glycoproteins that are reduced/absent in non-host-adapted bacteria. Analysis of wildtype and OAg-mutant bacteria indicated that the induced changes in surface carbohydrates involved both OAg and non-OAg species. To assess the impact of these HMW carbohydrates on the access of outer membrane constituents to antibody we used differentially-cultivated bacteria in vitro to immunoprecipitate antibodies directed against outer membrane moieties. We observed that the surface-carbohydrates induced during host-adaptation shield many outer membrane antigens from binding by antibody. Similar assays with normal mouse serum indicate that the induced HMW carbohydrates also impede complement deposition. Using an in vitro macrophage infection assay, we find that the bacterial HMW carbohydrate impedes TLR2-dependent, pro-inflammatory cytokine production by macrophages. Lastly we show that upon host-adaptation, the human-virulent strain, F. tularensis SchuS4 also induces capsule production with the effect of reducing macrophage-activation and accelerating tularemia pathogenesis in mice. CONCLUSION F. tularensis undergoes host-adaptation which includes production of multiple capsular materials. These capsules impede recognition of bacterial outer membrane constituents by antibody, complement, and Toll-Like Receptor 2. These changes in the host-pathogen interface have profound implications for pathogenesis and vaccine development.
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Affiliation(s)
- Tiffany M. Zarrella
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
| | - Anju Singh
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
| | - Constantine Bitsaktsis
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
| | - Tabassum Rahman
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
| | - Bikash Sahay
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
| | - Paul J. Feustel
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, New York, United States of America
| | - Edmund J. Gosselin
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
| | - Timothy J. Sellati
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
| | - Karsten R. O. Hazlett
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
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Zinman G, Brower-Sinning R, Emeche CH, Ernst J, Huang GTW, Mahony S, Myers AJ, O'Dee DM, Flynn JL, Nau GJ, Ross TM, Salter RD, Benos PV, Bar Joseph Z, Morel PA. Large scale comparison of innate responses to viral and bacterial pathogens in mouse and macaque. PLoS One 2011; 6:e22401. [PMID: 21789257 PMCID: PMC3138787 DOI: 10.1371/journal.pone.0022401] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Accepted: 06/21/2011] [Indexed: 11/19/2022] Open
Abstract
Viral and bacterial infections of the lower respiratory tract are major causes of morbidity and mortality worldwide. Alveolar macrophages line the alveolar spaces and are the first cells of the immune system to respond to invading pathogens. To determine the similarities and differences between the responses of mice and macaques to invading pathogens we profiled alveolar macrophages from these species following infection with two viral (PR8 and Fuj/02 influenza A) and two bacterial (Mycobacterium tuberculosis and Francisella tularensis Schu S4) pathogens. Cells were collected at 6 time points following each infection and expression profiles were compared across and between species. Our analyses identified a core set of genes, activated in both species and across all pathogens that were predominantly part of the interferon response pathway. In addition, we identified similarities across species in the way innate immune cells respond to lethal versus non-lethal pathogens. On the other hand we also found several species and pathogen specific response patterns. These results provide new insights into mechanisms by which the innate immune system responds to, and interacts with, invading pathogens.
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Affiliation(s)
- Guy Zinman
- Lane Center for Computational Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Rachel Brower-Sinning
- Department of Computational Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Chineye H. Emeche
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Jason Ernst
- Lane Center for Computational Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Grace Tzu-Wei Huang
- Department of Computational Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Shaun Mahony
- Department of Computational Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Amy J. Myers
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Dawn M. O'Dee
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - JoAnne L. Flynn
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Gerard J. Nau
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Ted M. Ross
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Russell D. Salter
- Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Panayiotis V. Benos
- Department of Computational Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Ziv Bar Joseph
- Lane Center for Computational Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (PAM); (ZBJ)
| | - Penelope A. Morel
- Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (PAM); (ZBJ)
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Periasamy S, Singh A, Sahay B, Rahman T, Feustel PJ, Pham GH, Gosselin EJ, Sellati TJ. Development of tolerogenic dendritic cells and regulatory T cells favors exponential bacterial growth and survival during early respiratory tularemia. J Leukoc Biol 2011; 90:493-507. [PMID: 21724804 DOI: 10.1189/jlb.0411197] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Tularemia is a vector-borne zoonosis caused by Ft, a Gram-negative, facultative intracellular bacterium. Ft exists in two clinically relevant forms, the European biovar B (holarctica), which produces acute, although mild, self-limiting infections, and the more virulent United States biovar A (tularensis), which is often associated with pneumonic tularemia and more severe disease. In a mouse model of tularemia, respiratory infection with the virulence-attenuated Type B (LVS) or highly virulent Type A (SchuS4) strain engenders peribronchiolar and perivascular inflammation. Paradoxically, despite an intense neutrophilic infiltrate and high bacterial burden, T(h)1-type proinflammatory cytokines (e.g., TNF, IL-1β, IL-6, and IL-12) are absent within the first ∼72 h of pulmonary infection. It has been suggested that the bacterium has the capacity to actively suppress or block NF-κB signaling, thus causing an initial delay in up-regulation of inflammatory mediators. However, our previously published findings and those presented herein contradict this paradigm and instead, strongly support an alternative hypothesis. Rather than blocking NF-κB, Ft actually triggers TLR2-dependent NF-κB signaling, resulting in the development and activation of tDCs and the release of anti-inflammatory cytokines (e.g., IL-10 and TGF-β). In turn, these cytokines stimulate development and proliferation of T(regs) that may restrain T(h)1-type proinflammatory cytokine release early during tularemic infection. The highly regulated and overall anti-inflammatory milieu established in the lung is permissive for unfettered growth and survival of Ft. The capacity of Ft to evoke such a response represents an important immune-evasive strategy.
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A Francisella tularensis locus required for spermine responsiveness is necessary for virulence. Infect Immun 2011; 79:3665-76. [PMID: 21670171 DOI: 10.1128/iai.00135-11] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Tularemia is a debilitating febrile illness caused by the category A biodefense agent Francisella tularensis. This pathogen infects over 250 different hosts, has a low infectious dose, and causes high morbidity and mortality. Our understanding of the mechanisms by which F. tularensis senses and adapts to host environments is incomplete. Polyamines, including spermine, regulate the interactions of F. tularensis with host cells. However, it is not known whether responsiveness to polyamines is necessary for the virulence of the organism. Through transposon mutagenesis of F. tularensis subsp. holarctica live vaccine strain (LVS), we identified FTL_0883 as a gene important for spermine responsiveness. In-frame deletion mutants of FTL_0883 and FTT_0615c, the homologue of FTL_0883 in F. tularensis subsp. tularensis Schu S4 (Schu S4), elicited higher levels of cytokines from human and murine macrophages compared to wild-type strains. Although deletion of FTL_0883 attenuated LVS replication within macrophages in vitro, the Schu S4 mutant with a deletion in FTT_0615c replicated similarly to wild-type Schu S4. Nevertheless, both the LVS and the Schu S4 mutants were significantly attenuated in vivo. Growth and dissemination of the Schu S4 mutant was severely reduced in the murine model of pneumonic tularemia. This attenuation depended on host responses to elevated levels of proinflammatory cytokines. These data associate responsiveness to polyamines with tularemia pathogenesis and define FTL_0883/FTT_0615c as an F. tularensis gene important for virulence and evasion of the host immune response.
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Common ancestry and novel genetic traits of Francisella novicida-like isolates from North America and Australia as revealed by comparative genomic analyses. Appl Environ Microbiol 2011; 77:5110-22. [PMID: 21666011 DOI: 10.1128/aem.00337-11] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Francisella novicida is a close relative of Francisella tularensis, the causative agent of tularemia. The genomes of F. novicida-like clinical isolates 3523 (Australian strain) and Fx1 (Texas strain) were sequenced and compared to F. novicida strain U112 and F. tularensis strain Schu S4. The strain 3523 chromosome is 1,945,310 bp and contains 1,854 protein-coding genes. The strain Fx1 chromosome is 1,913,619 bp and contains 1,819 protein-coding genes. NUCmer analyses revealed that the genomes of strains Fx1 and U112 are mostly colinear, whereas the genome of strain 3523 has gaps, translocations, and/or inversions compared to genomes of strains Fx1 and U112. Using the genome sequence data and comparative analyses with other members of the genus Francisella, several strain-specific genes that encode putative proteins involved in RTX toxin production, polysaccharide biosynthesis/modification, thiamine biosynthesis, glucuronate utilization, and polyamine biosynthesis were identified. The RTX toxin synthesis and secretion operon of strain 3523 contains four open reading frames (ORFs) and was named rtxCABD. Based on the alignment of conserved sequences upstream of operons involved in thiamine biosynthesis from various bacteria, a putative THI box was identified in strain 3523. The glucuronate catabolism loci of strains 3523 and Fx1 contain a cluster of nine ORFs oriented in the same direction that appear to constitute an operon. Strains U112 and Schu S4 appeared to have lost the loci for RTX toxin production, thiamine biosynthesis, and glucuronate utilization as a consequence of host adaptation and reductive evolution. In conclusion, comparative analyses provided insights into the common ancestry and novel genetic traits of these strains.
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Ruiz JC, D'Afonseca V, Silva A, Ali A, Pinto AC, Santos AR, Rocha AAMC, Lopes DO, Dorella FA, Pacheco LGC, Costa MP, Turk MZ, Seyffert N, Moraes PMRO, Soares SC, Almeida SS, Castro TLP, Abreu VAC, Trost E, Baumbach J, Tauch A, Schneider MPC, McCulloch J, Cerdeira LT, Ramos RTJ, Zerlotini A, Dominitini A, Resende DM, Coser EM, Oliveira LM, Pedrosa AL, Vieira CU, Guimarães CT, Bartholomeu DC, Oliveira DM, Santos FR, Rabelo ÉM, Lobo FP, Franco GR, Costa AF, Castro IM, Dias SRC, Ferro JA, Ortega JM, Paiva LV, Goulart LR, Almeida JF, Ferro MIT, Carneiro NP, Falcão PRK, Grynberg P, Teixeira SMR, Brommonschenkel S, Oliveira SC, Meyer R, Moore RJ, Miyoshi A, Oliveira GC, Azevedo V. Evidence for reductive genome evolution and lateral acquisition of virulence functions in two Corynebacterium pseudotuberculosis strains. PLoS One 2011; 6:e18551. [PMID: 21533164 PMCID: PMC3078919 DOI: 10.1371/journal.pone.0018551] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 03/11/2011] [Indexed: 02/02/2023] Open
Abstract
Background Corynebacterium pseudotuberculosis, a Gram-positive, facultative intracellular pathogen, is the etiologic agent of the disease known as caseous lymphadenitis (CL). CL mainly affects small ruminants, such as goats and sheep; it also causes infections in humans, though rarely. This species is distributed worldwide, but it has the most serious economic impact in Oceania, Africa and South America. Although C. pseudotuberculosis causes major health and productivity problems for livestock, little is known about the molecular basis of its pathogenicity. Methodology and Findings We characterized two C. pseudotuberculosis genomes (Cp1002, isolated from goats; and CpC231, isolated from sheep). Analysis of the predicted genomes showed high similarity in genomic architecture, gene content and genetic order. When C. pseudotuberculosis was compared with other Corynebacterium species, it became evident that this pathogenic species has lost numerous genes, resulting in one of the smallest genomes in the genus. Other differences that could be part of the adaptation to pathogenicity include a lower GC content, of about 52%, and a reduced gene repertoire. The C. pseudotuberculosis genome also includes seven putative pathogenicity islands, which contain several classical virulence factors, including genes for fimbrial subunits, adhesion factors, iron uptake and secreted toxins. Additionally, all of the virulence factors in the islands have characteristics that indicate horizontal transfer. Conclusions These particular genome characteristics of C. pseudotuberculosis, as well as its acquired virulence factors in pathogenicity islands, provide evidence of its lifestyle and of the pathogenicity pathways used by this pathogen in the infection process. All genomes cited in this study are available in the NCBI Genbank database (http://www.ncbi.nlm.nih.gov/genbank/) under accession numbers CP001809 and CP001829.
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Affiliation(s)
- Jerônimo C. Ruiz
- Research Center René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Vívian D'Afonseca
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Artur Silva
- Department of Genetics, Federal University of Pará, Belém, Pará, Brazil
| | - Amjad Ali
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Anne C. Pinto
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Anderson R. Santos
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Aryanne A. M. C. Rocha
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Débora O. Lopes
- Health Sciences Center, Federal University of São João Del Rei, Divinópilis, Minas Gerais, Brazil
| | - Fernanda A. Dorella
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Luis G. C. Pacheco
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Department of Biointeraction Sciences, Federal University of Bahia, Salvador, Bahia, Brazil
| | - Marcília P. Costa
- Department of Veterinary Medicine, State University of Ceará, Fortaleza, Ceará, Brazil
| | - Meritxell Z. Turk
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Núbia Seyffert
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Pablo M. R. O. Moraes
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Siomar C. Soares
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Sintia S. Almeida
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Thiago L. P. Castro
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Vinicius A. C. Abreu
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Eva Trost
- Department of Genetics, University of Bielefeld, CeBiTech, Bielefeld, Nordrhein-Westfale, Germany
| | - Jan Baumbach
- Department of Computer Science, Max-Planck-Institut für Informatik, Saarbrücken, Saarlan, Germany
| | - Andreas Tauch
- Department of Genetics, University of Bielefeld, CeBiTech, Bielefeld, Nordrhein-Westfale, Germany
| | | | - John McCulloch
- Department of Genetics, Federal University of Pará, Belém, Pará, Brazil
| | | | | | - Adhemar Zerlotini
- Research Center René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Anderson Dominitini
- Research Center René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Daniela M. Resende
- Research Center René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
- Department of Pharmaceutical Sciences, Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil
| | - Elisângela M. Coser
- Research Center René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Luciana M. Oliveira
- Department of Phisics, Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil
| | - André L. Pedrosa
- Department of Pharmaceutical Sciences, Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil
- Department of Biological Sciences, Federal University of Triangulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Carlos U. Vieira
- Department of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil
| | - Cláudia T. Guimarães
- Brazilian Agricultural Research Corporation (EMBRAPA), Sete Lagoas, Minas Gerais, Brazil
| | - Daniela C. Bartholomeu
- Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Diana M. Oliveira
- Department of Veterinary Medicine, State University of Ceará, Fortaleza, Ceará, Brazil
| | - Fabrício R. Santos
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Élida Mara Rabelo
- Department of Parasitology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Francisco P. Lobo
- Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Glória R. Franco
- Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Ana Flávia Costa
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Ieso M. Castro
- Department of Pharmacy, Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil
| | - Sílvia Regina Costa Dias
- Department of Parasitology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Jesus A. Ferro
- Department of Technology, State University of São Paulo, Jaboticabal, São Paulo, Brazil
| | - José Miguel Ortega
- Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Luciano V. Paiva
- Department of Chemistry, Federal University of Lavras, Lavras, Minas Gerais, Brazil
| | - Luiz R. Goulart
- Department of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil
| | - Juliana Franco Almeida
- Department of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil
| | - Maria Inês T. Ferro
- Department of Technology, State University of São Paulo, Jaboticabal, São Paulo, Brazil
| | - Newton P. Carneiro
- Brazilian Agricultural Research Corporation (EMBRAPA), Sete Lagoas, Minas Gerais, Brazil
| | - Paula R. K. Falcão
- Brazilian Agricultural Research Corporation (EMBRAPA), Campinas, São Paulo, Brazil
| | - Priscila Grynberg
- Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Santuza M. R. Teixeira
- Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Sérgio Brommonschenkel
- Department of Plant Pathology, Federal University of Viçosa, Viçosa, Minas Gerais, Brazil
| | - Sérgio C. Oliveira
- Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Roberto Meyer
- Department of Biointeraction Sciences, Federal University of Bahia, Salvador, Bahia, Brazil
| | | | - Anderson Miyoshi
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Guilherme C. Oliveira
- Research Center René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
- Center of Excellence in Bioinformatics, National Institute of Science and Technology, Research Center René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Vasco Azevedo
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- * E-mail:
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Cerqueira GM, Souza NM, Araújo ER, Barros AT, Morais ZM, Vasconcellos SA, Nascimento ALTO. Development of transcriptional fusions to assess Leptospira interrogans promoter activity. PLoS One 2011; 6:e17409. [PMID: 21445252 PMCID: PMC3060810 DOI: 10.1371/journal.pone.0017409] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 01/31/2011] [Indexed: 11/29/2022] Open
Abstract
Background Leptospirosis is a zoonotic infectious disease that affects both humans and animals. The existing genetic tools for Leptospira spp. have improved our understanding of the biology of this spirochete as well as the interaction of pathogenic leptospires with the mammalian host. However, new tools are necessary to provide novel and useful information to the field. Methodology and Principal Findings A series of promoter-probe vectors carrying a reporter gene encoding green fluorescent protein (GFP) were constructed for use in L. biflexa. They were tested by constructing transcriptional fusions between the lipL41, Leptospiral Immunoglobulin-like A (ligA) and Sphingomielynase 2 (sph2) promoters from L. interrogans and the reporter gene. ligA and sph2 promoters were the most active, in comparison to the lipL41 promoter and the non-induced controls. The results obtained are in agreement with LigA expression from the L. interrogans Fiocruz L1-130 strain. Conclusions The novel vectors facilitated the in vitro evaluation of L. interrogans promoter activity under defined growth conditions which simulate the mammalian host environment. The fluorescence and rt-PCR data obtained closely reflected transcriptional regulation of the promoters, thus demonstrating the suitability of these vectors for assessing promoter activity in L. biflexa.
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Akimana C, Kwaik YA. Francisella-arthropod vector interaction and its role in patho-adaptation to infect mammals. Front Microbiol 2011; 2:34. [PMID: 21687425 PMCID: PMC3109307 DOI: 10.3389/fmicb.2011.00034] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Accepted: 02/07/2011] [Indexed: 11/13/2022] Open
Abstract
Francisella tularensis is a Gram-negative, intracellular, zoonotic bacterium, and is the causative agent of tularemia with a broad host range. Arthropods such as ticks, mosquitoes, and flies maintain F. tularensis in nature by transmitting the bacteria among small mammals. While the tick is largely believed to be a biological vector of F. tularensis, transmission by mosquitoes and flies is largely believed to be mechanical on the mouthpart through interrupted feedings. However, the mechanism of infection of the vectors by F. tularensis is not well understood. Since F. tularensis has not been localized in the salivary gland of the primary human biting ticks, it is thought that bacterial transmission by ticks is through mechanical inoculation of tick feces containing F. tularensis into the skin wound. Drosophila melanogaster is an established good arthropod model for arthropod vectors of tularemia, where F. tularensis infects hemocytes, and is found in hemolymph, as seen in ticks. In addition, phagosome biogenesis and robust intracellular proliferation of F. tularensis in arthropod-derived cells are similar to that in mammalian macrophages. Furthermore, bacterial factors required for infectivity of mammals are often required for infectivity of the fly by F. tularensis. Several host factors that contribute to F. tularensis intracellular pathogenesis in D. melanogaster have been identified, and F. tularensis targets some of the evolutionarily conserved eukaryotic processes to enable intracellular survival and proliferation in evolutionarily distant hosts.
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Affiliation(s)
- Christine Akimana
- Department of Microbiology and Immunology, College of Medicine, University of Louisville Louisville, KY, USA
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Dai S, Mohapatra NP, Schlesinger LS, Gunn JS. Regulation of francisella tularensis virulence. Front Microbiol 2011; 1:144. [PMID: 21687801 PMCID: PMC3109300 DOI: 10.3389/fmicb.2010.00144] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 12/21/2010] [Indexed: 12/29/2022] Open
Abstract
Francisella tularensis is one of the most virulent bacteria known and a Centers for Disease Control and Prevention Category A select agent. It is able to infect a variety of animals and insects and can persist in the environment, thus Francisella spp. must be able to survive in diverse environmental niches. However, F. tularensis has a surprising dearth of sensory and regulatory factors. Recent advancements in the field have identified new functions of encoded transcription factors and greatly expanded our understanding of virulence gene regulation. Here we review the current knowledge of environmental adaptation by F. tularensis, its transcriptional regulators and their relationship to animal virulence.
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Affiliation(s)
- Shipan Dai
- Center for Microbial Interface Biology, The Ohio State University Columbus, OH, USA
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Francisella tularensis DeltapyrF mutants show that replication in nonmacrophages is sufficient for pathogenesis in vivo. Infect Immun 2010; 78:2607-19. [PMID: 20385757 DOI: 10.1128/iai.00134-10] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The pathogenesis of Francisella tularensis has been associated with this bacterium's ability to replicate within macrophages. F. tularensis can also invade and replicate in a variety of nonphagocytic host cells, including lung and kidney epithelial cells and hepatocytes. As uracil biosynthesis is a central metabolic pathway usually necessary for pathogens, we characterized DeltapyrF mutants of both F. tularensis LVS and Schu S4 to investigate the role of these mutants in intracellular growth. As expected, these mutant strains were deficient in de novo pyrimidine biosynthesis and were resistant to 5-fluoroorotic acid, which is converted to a toxic product by functional PyrF. The F. tularensis DeltapyrF mutants could not replicate in primary human macrophages. The inability to replicate in macrophages suggested that the F. tularensis DeltapyrF strains would be attenuated in animal infection models. Surprisingly, these mutants retained virulence during infection of chicken embryos and in the murine model of pneumonic tularemia. We hypothesized that the F. tularensis DeltapyrF strains may replicate in cells other than macrophages to account for their virulence. In support of this, F. tularensis DeltapyrF mutants replicated in HEK-293 cells and normal human fibroblasts in vitro. Moreover, immunofluorescence microscopy showed abundant staining of wild-type and mutant bacteria in nonmacrophage cells in the lungs of infected mice. These findings indicate that replication in nonmacrophages contributes to the pathogenesis of F. tularensis.
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