201
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Aepfelbacher M, Roppenser B, Hentschke M, Ruckdeschel K. Activity modulation of the bacterial Rho GAP YopE: an inspiration for the investigation of mammalian Rho GAPs. Eur J Cell Biol 2011; 90:951-4. [PMID: 21255863 DOI: 10.1016/j.ejcb.2010.12.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 12/15/2010] [Accepted: 12/15/2010] [Indexed: 12/16/2022] Open
Abstract
The Yersinia enterocolitica Rho GTPase Activating Protein (Rho GAP) YopE belongs to a group of bacterial virulence factors that is translocated into infected target cells by a type three secretion system. Structurally and biochemically YopE resembles eukaryotic Rho GAPs which control various cellular functions by modulating the activity of Rho GTP binding proteins. Here we summarise the published information on cellular effects, Rho protein substrates, compartmentalisation and turnover of YopE. A fascinating picture evolves of how this virulence factor integrates in host cellular regulatory mechanisms to fine tune bacterial pathogenicity.
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Affiliation(s)
- Martin Aepfelbacher
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.
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202
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Rosales-Mendoza S, Soria-Guerra RE, Moreno-Fierros L, Han Y, Alpuche-Solís AG, Korban SS. Transgenic carrot tap roots expressing an immunogenic F1-V fusion protein from Yersinia pestis are immunogenic in mice. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:174-180. [PMID: 20655621 DOI: 10.1016/j.jplph.2010.06.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Revised: 06/18/2010] [Accepted: 06/19/2010] [Indexed: 05/29/2023]
Abstract
Expression of the protective F1 and V antigens of Yersinia pestis, as a fusion protein, in carrot was pursued in an effort to develop an alternative vaccine production system against the serious plague disease. Transgenic carrot plants carrying the F1-V encoding gene were developed via Agrobacterium-mediated transformation. Presence, integration, and expression of the F1-V encoding gene were confirmed by polymerase chain reaction (PCR), DNA gel blot analysis, and reverse-transcriptase (RT)-PCR analyses, respectively. An ELISA assay confirmed the antigenicity of the plant-derived F1-V fusion protein. Immunogenicity was evaluated subcutaneously in mice using a soluble protein extract of freeze-dried transgenic carrot. Significant antibody levels were detected following immunization. These results demonstrated that the F1-V protein could be expressed in carrot tap roots, and that the carrot F1-V recombinant protein retained its antigenicity and immunogenicity.
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Affiliation(s)
- Sergio Rosales-Mendoza
- Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, Av. Dr. Manuel Nava 6, Mexico
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203
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The dependence of the Yersinia pestis capsule on pathogenesis is influenced by the mouse background. Infect Immun 2010; 79:644-52. [PMID: 21115720 DOI: 10.1128/iai.00981-10] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Yersinia pestis is a highly pathogenic Gram-negative organism and the causative agent of bubonic and pneumonic plague. Y. pestis is capable of causing major epidemics; thus, there is a need for vaccine targets and a greater understanding of the role of these targets in pathogenesis. Two prime Y. pestis vaccine candidates are the usher-chaperone fimbriae Psa and Caf. Herein we report that Y. pestis requires, in a nonredundant manner, both PsaA and Caf1 to achieve its full pathogenic ability in both pneumonic and bubonic plague in C57BL/6J mice. Deletion of psaA leads to a decrease in the organ bacterial burden and to a significant increase in the 50% lethal dose (LD₅₀) after subcutaneous infection. Deletion of caf1 also leads to a significant decrease in the organ bacterial burden but more importantly leads to a significantly greater increase in the LD₅₀ than was observed for the ΔpsaA mutant strain after subcutaneous infection of C57BL/6J mice. Furthermore, the degree of attenuation of the Δcaf1 mutant strain is mouse background dependent, as the Δcaf1 mutant strain was attenuated to a lesser degree in BALB/cJ mice by the subcutaneous route than in C57BL/6J mice. This observation that the degree of requirement for Caf1 is dependent on the mouse background indicates that the virulence of Y. pestis is dependent on the genetic makeup of its host and provides further support for the hypothesis that PsaA and Caf1 have different targets.
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204
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Felek S, Jeong JJ, Runco LM, Murray S, Thanassi DG, Krukonis ES. Contributions of chaperone/usher systems to cell binding, biofilm formation and Yersinia pestis virulence. MICROBIOLOGY-SGM 2010; 157:805-818. [PMID: 21088108 PMCID: PMC3081084 DOI: 10.1099/mic.0.044826-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Yersinia pestis genome sequencing projects have revealed six intact uncharacterized chaperone/usher systems with the potential to play roles in plague pathogenesis. We cloned each locus and expressed them in the Δfim Escherichia coli strain AAEC185 to test the assembled Y. pestis surface structures for various activities. Expression of each chaperone/usher locus gave rise to specific novel fibrillar structures on the surface of E. coli. One locus, y0561-0563, was able to mediate attachment to human epithelial cells (HEp-2) and human macrophages (THP-1) but not mouse macrophages (RAW264.7), while several loci were able to facilitate E. coli biofilm formation. When each chaperone/usher locus was deleted in Y. pestis, only deletion of the previously described pH 6 antigen (Psa) chaperone/usher system resulted in decreased adhesion and biofilm formation. Quantitative RT-PCR (qRT-PCR) revealed low expression levels for each novel chaperone/usher system in vitro as well as in mouse tissues following intravenous infection. However, a Y. pestis mutant in the chaperone/usher locus y1858-1862 was attenuated for virulence in mice via the intravenous route of infection, suggesting that expression of this locus is, at some stage, sufficient to affect the outcome of a plague infection. qRT-PCR experiments also indicated that expression of the chaperone/usher-dependent capsule locus, caf1, was influenced by oxygen availability and that the well-described chaperone/usher-dependent pilus, Psa, was strongly induced in minimal medium even at 28 °C rather than 37 °C, a temperature previously believed to be required for Psa expression. These data indicate several potential roles for the novel chaperone/usher systems of Y. pestis in pathogenesis and infection-related functions such as cell adhesion and biofilm formation.
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Affiliation(s)
- Suleyman Felek
- University of Michigan School of Dentistry, Department of Biologic and Materials Science, 1011 N. University, Dental Bldg 3209, Ann Arbor, MI 48109-1078, USA
| | - Jenny J Jeong
- University of Michigan School of Dentistry, Department of Biologic and Materials Science, 1011 N. University, Dental Bldg 3209, Ann Arbor, MI 48109-1078, USA
| | - Lisa M Runco
- New York Institute of Technology, Department of Life Sciences, NY, USA
| | - Susan Murray
- University of Michigan School of Public Health, Department of Biostatistics, MI, USA
| | - David G Thanassi
- Stony Brook University, Department of Molecular Genetics and Microbiology, Center for Infectious Diseases, NY, USA
| | - Eric S Krukonis
- University of Michigan School of Medicine, Department of Microbiology and Immunology, MI, USA.,University of Michigan School of Dentistry, Department of Biologic and Materials Science, 1011 N. University, Dental Bldg 3209, Ann Arbor, MI 48109-1078, USA
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205
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Evaluation of Psn, HmuR and a modified LcrV protein delivered to mice by live attenuated Salmonella as a vaccine against bubonic and pneumonic Yersinia pestis challenge. Vaccine 2010; 29:274-82. [PMID: 20979987 DOI: 10.1016/j.vaccine.2010.10.033] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 10/13/2010] [Indexed: 01/09/2023]
Abstract
We evaluated the ability of Yersinia pestis antigens HmuR, Psn and modified forms of LcrV delivered by live attenuated Salmonella strains to stimulate a protective immune response against subcutaneous or intranasal challenge with Y. pestis CO92. LcrV196 is a previously described truncated protein that includes aa 131-326 of LcrV and LcrV5214 has been modified to replace five key amino acids required for interaction with the TLR2 receptor. Psn is the outer membrane receptor for the siderophore, yersiniabactin, and the bacteriocin, pesticin. Mice immunized with Salmonella synthesizing Psn, LcrV196 or LcrV5214 developed serum IgG responses to the respective Yersinia antigen and were protected against pneumonic challenge with Y. pestis. Immunization with Salmonella synthesizing Psn or LcrV196 was sufficient to afford nearly full protection against bubonic challenge, while immunization with the strain synthesizing LcrV5214 was not protective. Immunization with Salmonella synthesizing HmuR, an outer membrane protein involved in heme acquisition in Y. pestis, was poorly immunogenic and did not elicit a protective response against either challenge route. These findings indicate that both Psn and LcrV196 delivered by Salmonella provide protection against both bubonic and pneumonic plague.
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206
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Yotsu R, Mii S, Hayashi R, Harada H, Furukawa K, Eto H. Erythema nodosum associated with Yersinia enterocolitica infection. J Dermatol 2010; 37:819-22. [PMID: 20883368 DOI: 10.1111/j.1346-8138.2010.00892.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a 74-year-old woman who presented to hospital with fever, vomiting, diarrhea, and 2 weeks later developed erythema nodosum (EN) on the legs, and was diagnosed with Yersinia enterocolitica infection based on her clinical course and microbiological examination of the stool. She also had a complication of pancreatitis, which made the diagnosis challenging. We should suspect infection by Y. enterocolitica when diagnosing cases of EN with gastrointestinal symptoms. We assume EN is likely to appear 2 weeks after the onset of gastrointestinal symptoms from our case and other case reports.
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Affiliation(s)
- Rie Yotsu
- Department of Dermatology, St Luke's International Hospital, Chuo-ku, Tokyo, Japan.
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207
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208
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The sequence of the pYV virulence plasmid from Yersinia enterocolitica strain WA-314 biogroup 1B serotype O:8. Plasmid 2010; 65:20-4. [PMID: 20875451 DOI: 10.1016/j.plasmid.2010.09.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 09/02/2010] [Accepted: 09/21/2010] [Indexed: 11/20/2022]
Abstract
Our laboratory strain Yersinia enterocolitica strain WA-314 biogroup 1B serotype O:8 displayed a different adhesion behavior to host cells compared to other Yersinia strains. To investigate whether this is based on differences in the gene content of the large pYV virulence plasmid which contains the major Yersinia adhesin YadA, we set out to sequence pYV(WA-314). pYV(WA-314) is very similar to pYV127/90, with a notable difference in the length of the Type III secretion system component YscP, which determines the needle length of the system. We found that we could improve the annotation of proteins previously described as "hypothetical" in pYV127/90 and other pYV plasmids, and show that pYV plasmids contain several and seemingly redundant plasmid partitioning and stabilization systems, explaining why these plasmids are not easily lost in laboratory cultures of Yersinia strains.
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209
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Yang F, Ke Y, Tan Y, Bi Y, Shi Q, Yang H, Qiu J, Wang X, Guo Z, Ling H, Yang R, Du Z. Cell membrane is impaired, accompanied by enhanced type III secretion system expression in Yersinia pestis deficient in RovA regulator. PLoS One 2010; 5:e12840. [PMID: 20862262 PMCID: PMC2941471 DOI: 10.1371/journal.pone.0012840] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Accepted: 08/21/2010] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND In the enteropathogenic Yersinia species, RovA regulates the expression of invasin, which is important for enteropathogenic pathogenesis but is inactivated in Yersinia pestis. Investigation of the RovA regulon in Y. pestis at 26 °C has revealed that RovA is a global regulator that contributes to virulence in part by the direct regulation of psaEFABC. However, the regulatory roles of RovA in Y. pestis at 37 °C, which allows most virulence factors in mammalian hosts to be expressed, are still poorly understood. METHODOLOGY/PRINCIPAL FINDINGS The transcriptional profile of an in-frame rovA mutant of Y. pestis biovar Microtus strain 201 was analyzed under type III secretion system (T3SS) induction conditions using microarray techniques, and it was revealed that many cell-envelope and transport/binding proteins were differentially expressed in the ΔrovA mutant. Most noticeably, many of the T3SS genes, including operons encoding the translocon, needle and Yop (Yersinia outer protein) effectors, were significantly up-regulated. Analysis of Yop proteins confirmed that YopE and YopJ were also expressed in greater amounts in the mutant. However, electrophoresis mobility shift assay results demonstrated that the His-RovA protein could not bind to the promoter sequences of the T3SS genes, suggesting that an indirect regulatory mechanism is involved. Transmission electron microscopy analysis indicated that there are small loose electron dense particle-like structures that surround the outer membrane of the mutant cells. The bacterial membrane permeability to CFSE (carboxyfluorescein diacetate succinimidyl ester) was significantly decreased in the ΔrovA mutant compared to the wild-type strain. Taken together, these results revealed the improper construction and dysfunction of the membrane in the ΔrovA mutant. CONCLUSIONS/SIGNIFICANCE We demonstrated that the RovA regulator plays critical roles in the construction and functioning of the bacterial membrane, which sheds considerable light on the regulatory functions of RovA in antibiotic resistance and environmental adaptation. The expression of T3SS was upregulated in the ΔrovA mutant through an indirect regulatory mechanism, which is possibly related to the altered membrane construction in the mutant.
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Affiliation(s)
- Fengkun Yang
- Department of Parasitology, Harbin Medical University, Harbin, Heilongjiang, China
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Yuehua Ke
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Yafang Tan
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Yujing Bi
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Qinghai Shi
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Huiying Yang
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Jinfu Qiu
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Xiaoyi Wang
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Zhaobiao Guo
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Hong Ling
- Department of Parasitology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Ruifu Yang
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Zongmin Du
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
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210
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von Altrock A, Roesler U, Merle R, Waldmann KH. Prevalence of pathogenic Yersinia enterocolitica strains on liver surfaces of pigs and their antimicrobial susceptibility. J Food Prot 2010; 73:1680-3. [PMID: 20828475 DOI: 10.4315/0362-028x-73.9.1680] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A study to determine the occurrence of pathogenic Yersinia enterocolitica on surfaces of slaughtered pig livers and the antimicrobial resistant pattern of the isolates was carried out in a slaughterhouse in Lower Saxony, Germany. During the slaughtering process, 1,500 surfaces of pig livers from 50 fattening herds were swabbed in order to isolate and characterize Y. enterocolitica isolates by serotyping, detecting the virulence plasmid coding the yopT gene, and resistance testing. Of the livers tested, 4.7% were positive for Y. enterocolitica O:3, which was the only identified serotype. The virulence gene yopT was found in 90.0% of these isolates. Antimicrobial susceptibility was tested by the broth dilution method, and the MICs were determined for 13 antimicrobials. All isolates were resistant to ampicillin and sulfamethoxazole but were susceptible to ciprofloxacin, nalidixic acid, gentamicin, ceftiofur, tetracycline, kanamycin, cefotaxime, and chlorphenicol. Up to now, resistance to florfenicol has always been described in combination with resistance to chloramphenicol. In the present study, 15.3% of the isolates were resistant to florfenicol, while no chloramphenicol-resistant strains could be identified. Multiresistance to three or more antimicrobials was detected in 22 strains (27.3%). Nevertheless, third-generation cephalosporines or fluoroquinolones, which were recommended for extraintestinal Y. enterocolitica infection in humans, were not affected.
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Affiliation(s)
- A von Altrock
- Clinic for Swine, Small Ruminants, Forensic Medicine and Ambulatory Service, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, Hannover, Germany.
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211
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Three Yersinia pestis adhesins facilitate Yop delivery to eukaryotic cells and contribute to plague virulence. Infect Immun 2010; 78:4134-50. [PMID: 20679446 DOI: 10.1128/iai.00167-10] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
To establish a successful infection, Yersinia pestis requires the delivery of cytotoxic Yops to host cells. Yops inhibit phagocytosis, block cytokine responses, and induce apoptosis of macrophages. The Y. pestis adhesin Ail facilitates Yop translocation and is required for full virulence in mice. To determine the contributions of other adhesins to Yop delivery, we deleted five known adhesins of Y. pestis. In addition to Ail, plasminogen activator (Pla) and pH 6 antigen (Psa) could mediate Yop translocation to host cells. The contribution of each adhesin to binding and Yop delivery was dependent upon the growth conditions. When cells were pregrown at 28°C and pH 7, the order of importance for adhesins in cell binding and cytotoxicity was Ail > Pla > Psa. Y. pestis grown at 37°C and pH 7 had equal contributions from Ail and Pla but an undetectable role for Psa. At 37°C and pH 6, both Ail and Psa contributed to binding and Yop delivery, while Pla contributed minimally. Pla-mediated Yop translocation was independent of protease activity. Of the three single mutants, the Δail mutant was the most defective in mouse virulence. The expression level of ail was also the highest of the three adhesins in infected mouse tissues. Compared to an ail mutant, additional deletion of psaA (encoding Psa) led to a 130,000-fold increase in the 50% lethal dose for mice relative to that of the KIM5 parental strain. Our results indicate that in addition to Ail, Pla and Psa can serve as environmentally specific adhesins to facilitate Yop secretion, a critical virulence function of Y. pestis.
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212
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Flashner Y, Fisher M, Tidhar A, Mechaly A, Gur D, Halperin G, Zahavy E, Mamroud E, Cohen S. The search for early markers of plague: evidence for accumulation of solubleYersinia pestisLcrV in bubonic and pneumonic mouse models of disease. ACTA ACUST UNITED AC 2010; 59:197-206. [DOI: 10.1111/j.1574-695x.2010.00687.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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213
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Eroshenko GA, Odinokov GN, Kukleva LM, Krasnov YM, Kutyrev VV. Sequence analysis of the yadA, inv, and ail genes and their expression in the main and nonmain Yersinia pestis subspecies and Yersinia pseudotuberculosis. RUSS J GENET+ 2010. [DOI: 10.1134/s1022795410060025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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214
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Silva MT. Bacteria-induced phagocyte secondary necrosis as a pathogenicity mechanism. J Leukoc Biol 2010; 88:885-96. [PMID: 20566623 DOI: 10.1189/jlb.0410205] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Triggering of phagocyte apoptosis is a major virulence mechanism used by some successful bacterial pathogens. A central issue in the apoptotic death context is that fully developed apoptosis results in necrotic cell autolysis (secondary necrosis) with release of harmful cell components. In multicellular animals, this occurs when apoptosing cells are not removed by scavengers, mainly macrophages. Secondary necrotic lysis of neutrophils and macrophages may occur in infection when extensive phagocyte apoptosis is induced by bacterial cytotoxins and removal of apoptosing phagocytes is defective because the apoptotic process exceeds the available scavenging capacity or targets macrophages directly. Induction of phagocyte secondary necrosis is an important pathogenic mechanism, as it combines the pathogen evasion from phagocyte antimicrobial activities and the release of highly cytotoxic molecules, particularly of neutrophil origin, such as neutrophil elastase. This pathogenicity mechanism therefore promotes the unrestricted multiplication of the pathogen and contributes directly to the pathology of several necrotizing infections, where extensive apoptosis and necrosis of macrophages and neutrophils are present. Here, examples of necrotizing infectious diseases, where phagocyte secondary necrosis is implicated, are reviewed.
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Affiliation(s)
- Manuel T Silva
- Instituto de Biologia Molecular e Celular, University of Porto, Rua do Campo Alegre 823, Porto, Portugal.
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215
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Ail binding to fibronectin facilitates Yersinia pestis binding to host cells and Yop delivery. Infect Immun 2010; 78:3358-68. [PMID: 20498264 DOI: 10.1128/iai.00238-10] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Yersinia pestis, the causative agent of plague, evades host immune responses and rapidly causes disease. The Y. pestis adhesin Ail mediates host cell binding and is critical for Yop delivery. To identify the Ail receptor(s), Ail was purified following overexpression in Escherichia coli. Ail bound specifically to fibronectin, an extracellular matrix protein with the potential to act as a bridge between Ail and host cells. Ail expressed by E. coli also mediated binding to purified fibronectin, and Ail-mediated E. coli adhesion to host cells was dependent on fibronectin. Ail expressed by Y. pestis bound purified fibronectin, as did the Y. pestis adhesin plasminogen activator (Pla). However, a KIM5 Delta ail mutant had decreased binding to host cells, while a KIM5 Delta pla mutant had no significant defect in adhesion. Furthermore, treatment with antifibronectin antibodies decreased Ail-mediated adhesion by KIM5 and the KIM5 Delta pla mutant, indicating that the Ail-fibronectin interaction was important for cell binding. Finally, antifibronectin antibodies inhibited the KIM5-mediated cytotoxicity of host cells in an Ail-dependent fashion. These data indicate that Ail is a key adhesin that mediates binding to host cells through interaction with fibronectin on the surface of host cells, and this interaction is important for Yop delivery by Y. pestis.
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216
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Adgamov RR, Timchenko NF, Allenov AV, Ermolaeva SA. Variability of inv gene fragment encoding functionally important domain of invasion of Yersinia pseudotuberculosis. MOLECULAR GENETICS MICROBIOLOGY AND VIROLOGY 2010. [DOI: 10.3103/s0891416810010040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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217
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Iwata T, Une Y, Lee KI, Nakamura SI, Taniguchi T, Hayashidani H. Seroepidemiological survey of pathogenic Yersinia in breeding squirrel monkeys in Japan. J Vet Med Sci 2010; 72:981-4. [PMID: 20234111 DOI: 10.1292/jvms.09-0505] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To investigate the prevalence of antibodies to pathogenic Yersinia in breeding squirrel monkeys, the serum samples of 252 squirrel monkeys from 9 zoological gardens in Japan were tested by ELISA using plasmid-encoded Yersinia outer membrane protein (Yops) as the antigen. The cutoff value was calculated by using the serum samples of the squirrel monkeys from Suriname, where no prevalence of pathogenic Yersinia have been reported. According to the cutoff value, 164 of 252 (65.1%) squirrel monkeys were considered positive against pathogenic Yersinia. These positive monkeys belonged to 8 of the 9 zoological gardens, and the percentage of the seropositive monkeys ranged from 22.2 to 89.4%. Furthermore, in one zoological garden, the positive rate of the squirrel monkeys which were over 1 year old (95.7%) was significantly higher than those which were under 1 year old (23.3%). These results suggested that pathogenic Yersinia is highly prevalent among breeding monkeys in Japan.
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Affiliation(s)
- Taketoshi Iwata
- Division of Animal Life Science, Institute of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
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218
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The small RNA chaperone Hfq is required for the virulence of Yersinia pseudotuberculosis. Infect Immun 2010; 78:2034-44. [PMID: 20231416 DOI: 10.1128/iai.01046-09] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Bacterial small, noncoding RNAs (sRNAs) participate in the posttranscriptional regulation of gene expression, often by affecting protein translation, transcript stability, and/or protein activity. For proper function, many sRNAs rely on the chaperone Hfq, which mediates the interaction of the sRNA with its target mRNA. Recent studies have demonstrated that Hfq contributes to the pathogenesis of a number of bacterial species, suggesting that sRNAs play an essential role in the regulation of virulence. The enteric pathogen Yersinia pseudotuberculosis causes the disease yersiniosis. Here we show that Hfq is required by Y. pseudotuberculosis to cause mortality in an intragastric mouse model of infection, and a strain lacking Hfq is attenuated 1,000-fold compared to the wild type. Hfq is also required for virulence through the intraperitoneal route of infection and for persistence of the bacterium in the Peyer's patches, mesenteric lymph nodes, and spleen, suggesting a role for Hfq in systemic infection. Furthermore, the Deltahfq mutant of Y. pseudotuberculosis is hypermotile and displays increased production of a biosurfactant-like substance, reduced intracellular survival in macrophages, and decreased production of type III secretion effector proteins. Together, these data demonstrate that Hfq plays a critical role in the virulence of Y. pseudotuberculosis by participating in the regulation of multiple steps in the pathogenic process and further highlight the unique role of Hfq in the virulence of individual pathogens.
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219
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Palonen E, Lindström M, Korkeala H. Adaptation of enteropathogenic Yersinia to low growth temperature. Crit Rev Microbiol 2010; 36:54-67. [PMID: 20088683 DOI: 10.3109/10408410903382581] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Yersinia enterocolitica and Yersinia pseudotuberculosis are important foodborne pathogens that cause infections through contaminated refrigerated food. Their cold tolerance mechanisms are therefore of special interest. Adaptation to cold involves changes in protein synthesis and in cell membranes to overcome diminished transcriptional and translational efficiency and reduced fluidity of cell membranes. Studies of low temperature adaptation mechanisms have mainly been performed on mesophilic bacteria, while most modern food hygiene risks are caused by psychrotrophs. Understanding low temperature adaptation of psychrotrophs would help to control these pathogens. This review demonstrates that more studies on cold tolerance mechanisms of psychrotrophs are needed.
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Affiliation(s)
- Eveliina Palonen
- Department of Food and Environmental Hygiene, University of Helsinki, Finland.
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Pathogenic strains of Yersinia enterocolitica isolated from domestic dogs (Canis familiaris) belonging to farmers are of the same subtype as pathogenic Y. enterocolitica strains isolated from humans and may be a source of human infection in Jiangsu Province, China. J Clin Microbiol 2010; 48:1604-10. [PMID: 20181899 DOI: 10.1128/jcm.01789-09] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We isolated 326 Yersinia enterocolitica strains from 5,919 specimens from patients with diarrhea at outpatient clinics, livestock, poultry, wild animals, insect vectors, food, and the environment in the cities of Nantong and Xuzhou in Jiangsu Province, China, from 2004 to 2008. The results showed that the 12 pathogenic strains were of the O:3 serotype. Six strains were isolated from domestic dogs (Canis familiaris) belonging to farmers and were found to be the primary carriers of pathogenic Y. enterocolitica strains, especially in Xuzhou. Pulsed-field gel electrophoresis analysis of the pathogenic strains from dogs belonging to farmers showed that they shared the same patterns as strains from diarrhea patients isolated in 1994. This indicates that the strains from domestic dogs have a close correlation with the strains causing human infections.
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Neutrophils are resistant to Yersinia YopJ/P-induced apoptosis and are protected from ROS-mediated cell death by the type III secretion system. PLoS One 2010; 5:e9279. [PMID: 20174624 PMCID: PMC2823771 DOI: 10.1371/journal.pone.0009279] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Accepted: 01/30/2010] [Indexed: 12/18/2022] Open
Abstract
Background The human innate immune system relies on the coordinated activity of macrophages and polymorphonuclear leukocytes (neutrophils or PMNs) for defense against bacterial pathogens. Yersinia spp. subvert the innate immune response to cause disease in humans. In particular, the Yersinia outer protein YopJ (Y. pestis and Y. pseudotuberculosis) and YopP (Y. enterocolitica) rapidly induce apoptosis in murine macrophages and dendritic cells. However, the effects of Yersinia Yop J/P on neutrophil fate are not clearly defined. Methodology/Principal Findings In this study, we utilized wild-type and mutant strains of Yersinia to test the contribution of YopJ and YopP on induction of apoptosis in human monocyte-derived macrophages (HMDM) and neutrophils. Whereas YopJ and YopP similarly induced apoptosis in HMDMs, interaction of human neutrophils with virulence plasmid-containing Yersinia did not result in PMN caspase activation, release of LDH, or loss of membrane integrity greater than PMN controls. In contrast, interaction of human PMNs with the virulence plasmid-deficient Y. pestis strain KIM6 resulted in increased surface exposure of phosphatidylserine (PS) and cell death. PMN reactive oxygen species (ROS) production was inhibited in a virulence plasmid-dependent but YopJ/YopP-independent manner. Following phagocytic interaction with Y. pestis strain KIM6, inhibition of PMN ROS production with diphenyleneiodonium chloride resulted in a reduction of PMN cell death similar to that induced by the virulence plasmid-containing strain Y. pestis KIM5. Conclusions Our findings showed that Yersinia YopJ and/or YopP did not induce pronounced apoptosis in human neutrophils. Furthermore, robust PMN ROS production in response to virulence plasmid-deficient Yersinia was associated with increased PMN cell death, suggesting that Yersinia inhibition of PMN ROS production plays a role in evasion of the human innate immune response in part by limiting PMN apoptosis.
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Abstract
The potential application of Yersinia pestis for bioterrorism emphasizes the urgent need to develop more effective vaccines against airborne infection. The current status of plague vaccines has been reviewed. The present emphasis is on subunit vaccines based on the F1 and LcrV antigens. These provide good protection in animal models but may not protect against F1 strains with modifications to the type III secretion system. The duration of protection against pneumonic infection is also uncertain. Other strategies under investigation include defined live-attenuated vaccines, DNA vaccines, mucosal delivery systems and heterologous immunization. The live-attenuated strain Y. pestis EV NIIEG protects against aerosol challenge in animal models and, with further modification to reduce residual virulence and to optimize respiratory protection, it could provide a shortcut to improved vaccines. The regulatory problems inherent in licensing vaccines for which efficacy data are unavailable and their possible solutions are discussed herein.
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Affiliation(s)
- Valentina A Feodorova
- Scientific and Research Institute for Medical and Veterinary Biotechnologies, Russia-Switzerland, Branch in Saratov, 9 Proviantskaya Street, Box 1580, Saratov 410028, Russia.
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223
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Cytosol as battleground: ubiquitin as a weapon for both host and pathogen. Trends Cell Biol 2010; 20:205-13. [PMID: 20129784 DOI: 10.1016/j.tcb.2010.01.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Revised: 01/04/2010] [Accepted: 01/05/2010] [Indexed: 01/24/2023]
Abstract
Ubiquitin was first described as a tag allowing cells to degrade and recycle their own proteins. Recent research has shown ubiquitin to be central for immune system recognition of invading bacteria. This review describes a set of complex host-pathogen interactions that are dependent on ubiquitination. From the host perspective, ubiquitin-dependent activation of inflammation and degradation of bacterial effectors is protective. Several pathogens become ubiquitinated in the host cell cytosol, and recent research suggests that this could trigger a form of autophagy, increasingly recognized as an important mechanism for the control of infection by a variety of human pathogens. Meanwhile, bacteria have developed mechanisms to evade or exploit the fundamental processes activated by ubiquitination, producing both ubiquitin ligases and deubiquitinases that modulate host responses.
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Yersinia pestis with regulated delayed attenuation as a vaccine candidate to induce protective immunity against plague. Infect Immun 2010; 78:1304-13. [PMID: 20086087 DOI: 10.1128/iai.01122-09] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Two mutant strains of Yersinia pestis KIM5+, a Deltacrp mutant and a mutant with arabinose-dependent regulated delayed-shutoff crp expression (araC P(BAD) crp), were constructed, characterized in vitro, and evaluated for virulence, immunogenicity, and protective efficacy in mice. Both strains were highly attenuated by the subcutaneous (s.c.) route. The 50% lethal doses (LD(50)s) of the Deltacrp and araC P(BAD) crp mutants were approximately 1,000,000-fold and 10,000-fold higher than those of Y. pestis KIM5+, respectively, indicating that both strains were highly attenuated. Mice vaccinated s.c. with 3.8 x 10(7) CFU of the Deltacrp mutant developed high anti-Y. pestis and anti-LcrV serum IgG titers, both with a strong Th2 bias, and induced protective immunity against subcutaneous challenge with virulent Y. pestis (80% survival) but no protection against pulmonary challenge. Mice vaccinated with 3.0 x 10(4) CFU of the araC P(BAD) crp mutant also developed high anti-Y. pestis and anti-LcrV serum IgG titers but with a more balanced Th1/Th2 response. This strain induced complete protection against s.c. challenge and partial protection (70% survival) against pulmonary challenge. Our results demonstrate that arabinose-dependent regulated crp expression is an effective strategy to attenuate Y. pestis while retaining strong immunogenicity, leading to protection against the pneumonic and bubonic forms of plague.
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225
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Bhagat N, Virdi JS. Molecular and biochemical characterization of urease and survival of Yersinia enterocolitica biovar 1A in acidic pH in vitro. BMC Microbiol 2009; 9:262. [PMID: 20017936 PMCID: PMC2806259 DOI: 10.1186/1471-2180-9-262] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Accepted: 12/17/2009] [Indexed: 12/30/2022] Open
Abstract
Background Yersinia enterocolitica, an important food- and water-borne enteric pathogen is represented by six biovars viz. 1A, 1B, 2, 3, 4 and 5. Despite the lack of recognized virulence determinants, some biovar 1A strains have been reported to produce disease symptoms resembling that produced by known pathogenic biovars (1B, 2-5). It is therefore imperative to identify determinants that might contribute to the pathogenicity of Y. enterocolitica biovar 1A strains. Y. enterocolitica invariably produces urease and the role of this enzyme in the virulence of biovar 1B and biovar 4 strains has been reported recently. The objective of this work was to study genetic organization of the urease (ure) gene complex of Y. enterocolitica biovar 1A, biochemical characterization of the urease, and the survival of these strains under acidic conditions in vitro. Results The ure gene complex (ureABCEFGD) of Y. enterocolitica biovar 1A included three structural and four accessory genes, which were contiguous and was flanked by a urea transport (yut) gene on the 3' side. Differences were identified in ure gene complex of biovar 1A strain compared to biovar 1B and 4 strains. This included a smaller ureB gene and larger intergenic regions between the structural genes. The crude urease preparation exhibited optimal pH and temperature of 5.5 and 65°C respectively, and Michaelis-Menten kinetics with a Km of 1.7 ± 0.4 mM urea and Vmax of 7.29 ± 0.42 μmol of ammonia released/min/mg protein. The urease activity was dependent on growth temperature and growth phase of Y. enterocolitica biovar 1A, and the presence of nickel in the medium. The molecular mass of the enzyme was > 545 kDa and an isoelectric point of 5.2. The number of viable Y. enterocolitica biovar 1A decreased significantly when incubated at pH 2.5 for 2 h. However, no such decrease was observed at this pH in the presence of urea. Conclusions The ure gene cluster of biovar 1A strains though similar to biovar 1B and 4 strains, exhibited important differences. The study also showed the ability of biovar 1A strains of Y. enterocolitica to survive at highly acidic pH in vitro in the presence of urea.
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Affiliation(s)
- Neeru Bhagat
- Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi - 110 021,
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Quenee LE, Berube BJ, Segal J, Elli D, Ciletti NA, Anderson D, Schneewind O. Amino acid residues 196-225 of LcrV represent a plague protective epitope. Vaccine 2009; 28:1870-6. [PMID: 20005318 DOI: 10.1016/j.vaccine.2009.11.076] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2009] [Revised: 10/09/2009] [Accepted: 11/27/2009] [Indexed: 12/28/2022]
Abstract
LcrV, a protein that resides at the tip of the type III secretion needles of Yersinia pestis, is the single most important plague protective antigen. Earlier work reported monoclonal antibody MAb 7.3, which binds a conformational epitope of LcrV and protects experimental animals against lethal plague challenge. By screening monoclonal antibodies directed against LcrV for their ability to protect immunized mice against bubonic plague challenge, we examined here the possibility of additional protective epitopes. MAb BA5 protected animals against plague, neutralized the Y. pestis type III secretion pathway and promoted opsonophagocytic clearance of bacteria in blood. LcrV residues 196-225 were necessary and sufficient for MAb BA5 binding. Compared to full-length LcrV, a variant lacking its residues 196-225 retained the ability of eliciting plague protection. These results identify LcrV residues 196-225 as a linear epitope that is recognized by the murine immune system to confer plague protection.
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Affiliation(s)
- Lauriane E Quenee
- Department of Microbiology, University of Chicago, 920 East 58th Street, Chicago, IL 60637, USA
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Blaylock B, Berube BJ, Schneewind O. YopR impacts type III needle polymerization in Yersinia species. Mol Microbiol 2009; 75:221-9. [PMID: 19968786 DOI: 10.1111/j.1365-2958.2009.06988.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A hallmark of Yersinia type III machines is the presence of needles extending from the bacterial surface. Needles perform two functions, serving as the conduits for the transport of effectors into immune cells but also acting as a sensor. The polymerized needle protein, YscF, is thought to perceive threshold levels of environmental calcium ions to trigger secretion. yopR (yscH) is a gene downstream of yscEFG, encoding the chaperones and principal building blocks of the needle. Here we investigated the contribution of YopR towards type III secretion and pathogenesis. Yersinia pestis KIM D27 mutants lacking yopR were defective for virulence in a mouse model of septicemic plague. yopR variants of Yersinia enterocolitica W22703 displayed a reduced ability to inject effectors into macrophages and required lower calcium concentrations to activate type III secretion than wild-type yersiniae. Furthermore, yopR mutants failed to assemble YscF into needle complexes and instead secreted YscF into the medium. These results imply that YopR may be involved in controlling the secretion of YscF, thereby impacting the assembly of type III machines. An alternative possibility, which YopR participates directly in the polymerization of YscF, seems less likely as YopR is not associated with purified needles.
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Affiliation(s)
- Bill Blaylock
- Department of Microbiology, University of Chicago, Chicago, IL 60637, USA
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228
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Humans and evolutionary and ecological forces shaped the phylogeography of recently emerged diseases. Nat Rev Microbiol 2009; 7:813-21. [PMID: 19820723 DOI: 10.1038/nrmicro2219] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The development of human civilizations and global commerce has led to the emergence and worldwide circulation of many infectious diseases. Anthrax, plague and tularaemia are three zoonotic diseases that have been intensely studied through genome characterization of the causative species and phylogeographical analyses. A few highly fit genotypes in each species represent the causative agents for most of the observed disease cases. Together, mutational and selective forces create highly adapted pathogens, but this must be coupled with ecological opportunities for global expansion. This Review describes the distributions of the bacteria that cause anthrax, plague and tularaemia and investigates the forces that created clonal structures in these species.
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Bi Y, Du Z, Yang H, Guo Z, Tan Y, Zhu Z, Yang R. Reduced apoptosis of mouse macrophages induced by yscW mutant of Yersinia pestis results from the reduced secretion of YopJ and relates to caspase-3 signal pathway. Scand J Immunol 2009; 70:358-67. [PMID: 19751270 DOI: 10.1111/j.1365-3083.2009.02297.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The virulence of the pathogenic Yersinia species depends on a plasmid-encoded type III secretion system (T3SS) that injects six Yersinia outer protein (Yop) effector proteins into the cytosol of macrophages, leading to disruption of host defence mechanisms. Here, we report that a T3SS structural protein YscW of Yersinia pestis contributed to the induction of apoptosis of murine macrophages. The apoptotic percentage of macrophages, from both mouse peritoneal cavity and spleen, and of RAW264.7 cell line, caused by the yscW mutant strain was significantly lower than that by wild type (WT) Y. pestis and yscW complemented strain. Meanwhile, detection of caspase-3 activity in macrophages, a key apoptosis-inducing protein, showed coincident results with the changes of macrophage apoptosis induced by WT, yscW mutant and complemented strains, indicating that macrophage apoptosis was related to caspase-3 signal pathways. However, ectopic expression of YscW in RAW264.7 cells cannot increase the macrophage apoptosis and death, suggesting that YscW itself could not induce macrophage apoptosis directly. To get insight into the mechanism of this phenomenon, we investigated the secretion of YopJ, which has been thought to be the only Yop effector related to apoptosis, in WT, mutant and complemented strains, respectively. Results showed that in yscW mutant strain, secretion of YopJ was decreased significantly in the supernatant than that in WT or complemented strain. This means although YscW does not induce apoptosis directly, it can indirectly affect apoptosis through reducing the secretion of YopJ.
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Affiliation(s)
- Y Bi
- Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
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Adding to Yersinia enterocolitica gene pool diversity: two cryptic plasmids from a biotype 1A isolate. J Biomed Biotechnol 2009; 2009:398434. [PMID: 19834620 PMCID: PMC2760160 DOI: 10.1155/2009/398434] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 06/21/2009] [Accepted: 07/13/2009] [Indexed: 01/15/2023] Open
Abstract
We report the nucleotide sequence of two novel cryptic plasmids (4357 and 14 662 base pairs) carried by a Yersinia enterocolitica biotype 1A strain isolated from pork. As distinguished from most biotype 1A strains, this isolate, designated 07-04449, exhibited adherence to eukaryotic cells. The smaller plasmid pYe4449-1 carries five attributable open reading frames (ORFs) encoding the first CcdA/CcdB-like antitoxin/toxin system described for a Yersinia plasmid, a RepA-like replication initiation protein, and mobilizing factors MobA and MobC. The deduced amino acid sequences showed highest similarity to proteins described in Salmonella (CcdA/B), Klebsiella (RepA), and Plesiomonas (MobA/C) indicating genomic fluidity among members of the Enterobacteriaceae. One additional ORF with unknown function, termed ORF5, was identified with an ancestry distinct from the rest of the plasmid. While the C+G content of ORF5 is 38.3%, the rest of pYe4449-1 shows a C+G content of 55.7%. The C+G content of the larger plasmid pYe4449-2 (54.9%) was similar to that of pYe4449-1 (53.7%) and differed from that of the Y. enterocolitica genome (47.3%). Of the 14 ORFs identified on pYe4449-2, only six ORFs showed significant similarity to database entries. For three of these ORFs likely functions could be ascribed: a TnpR-like resolvase and a phage replication protein, localized each on a low C+G island, and DNA primase TraC. Two ORFs of pYe4449-2, ORF3 and ORF7, seem to encode secretable proteins. Epitope-tagging of ORF3 revealed protein expression at 4 degrees C but not at or above 27 degrees C suggesting adaptation to a habitat outside swine. The hypothetical protein encoded by ORF7 is the member of a novel repeat protein family sharing the DxxGN(x)(n)DxxGN motif. Our findings illustrate the exceptional gene pool diversity within the species Y. enterocolitica driven by horizontal gene transfer events.
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Grimes DJ, Johnson CN, Dillon KS, Flowers AR, Noriea NF, Berutti T. What genomic sequence information has revealed about Vibrio ecology in the ocean--a review. MICROBIAL ECOLOGY 2009; 58:447-460. [PMID: 19727929 DOI: 10.1007/s00248-009-9578-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 08/07/2009] [Indexed: 05/28/2023]
Abstract
To date, the genomes of eight Vibrio strains representing six species and three human pathogens have been fully sequenced and reported. This review compares genomic information revealed from these sequencing efforts and what we can infer about Vibrio biology and ecology from this and related genomic information. The focus of the review is on those attributes that allow the Vibrios to survive and even proliferate in their ocean habitats, which include seawater, plankton, invertebrates, fish, marine mammals, plants, man-made structures (surfaces), and particulate matter. Areas covered include general information about the eight genomes, each of which is distributed over two chromosomes; a discussion of expected and unusual genes found; attachment sites and mechanisms; utilization of particulate and dissolved organic matter; and conclusions.
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Affiliation(s)
- Darrell Jay Grimes
- Department of Coastal Sciences, Gulf Coast Research Laboratory, The University of Southern Mississippi, 703 East Beach Drive, Ocean Springs, MS 39564, USA.
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N255 is a key residue for recognition by a monoclonal antibody which protects against Yersinia pestis infection. Vaccine 2009; 27:7073-9. [PMID: 19786138 DOI: 10.1016/j.vaccine.2009.09.061] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 09/02/2009] [Accepted: 09/16/2009] [Indexed: 11/24/2022]
Abstract
Mab7.3 to Yersinia pestis LcrV antigen (LcrV(Ype)) protected J774A.1 macrophages in vitro from killing by a Yersinia pseudotuberculosis strain expressing LcrV(Ype). Of 4 site-directed mutations in the coiled-coil region (148-169) and 7 mutations in the 225-255 sequence of LcrV(Ype), only the mutation of N255 to D255, abrogated the binding of Mab7.3 and reduced its protective capacity against plague. Since the Mab7.3 epitope in LcrV(Ype) (135-275) encompasses a region (136-180) thought to be exposed on the injectisome, we suggest that Mab7.3 protects by binding to LcrV(Ype) and interfering with protein-protein interactions necessary for type three secretion.
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An D, Apidianakis Y, Boechat AL, Baldini RL, Goumnerov BC, Rahme LG. The pathogenic properties of a novel and conserved gene product, KerV, in proteobacteria. PLoS One 2009; 4:e7167. [PMID: 19779606 PMCID: PMC2744870 DOI: 10.1371/journal.pone.0007167] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Accepted: 08/19/2009] [Indexed: 12/27/2022] Open
Abstract
Identification of novel virulence factors is essential for understanding bacterial pathogenesis and designing antibacterial strategies. In this study, we uncover such a factor, termed KerV, in Proteobacteria. Experiments carried out in a variety of eukaryotic host infection models revealed that the virulence of a Pseudomonas aeruginosa kerV null mutant was compromised when it interacted with amoebae, plants, flies, and mice. Bioinformatics analyses indicated that KerV is a hypothetical methyltransferase and is well-conserved across numerous Proteobacteria, including both well-known and emerging pathogens (e.g., virulent Burkholderia, Escherichia, Shigella, Vibrio, Salmonella, Yersinia and Brucella species). Furthermore, among the 197 kerV orthologs analyzed in this study, about 89% reside in a defined genomic neighborhood, which also possesses essential DNA replication and repair genes and detoxification gene. Finally, infection of Drosophila melanogaster with null mutants demonstrated that KerV orthologs are also crucial in Vibrio cholerae and Yersinia pseudotuberculosis pathogenesis. Our findings suggested that KerV has a novel and broad significance as a virulence factor in pathogenic Proteobacteria and it might serve as a new target for antibiotic drug design.
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Affiliation(s)
- Dingding An
- Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Research Institute, Boston, Massachusetts, United States of America
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Yiorgos Apidianakis
- Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Research Institute, Boston, Massachusetts, United States of America
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ana Laura Boechat
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Regina L. Baldini
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Boyan C. Goumnerov
- Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Laurence G. Rahme
- Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Shriners Research Institute, Boston, Massachusetts, United States of America
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: .
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Uppada JB, Khan AA, Bhat AA, Deshmukh R, Rao DN. Humoral immune responses and protective efficacy of sequential B- and T-cell epitopes of V antigen of Yersinia pestis by intranasal immunization in microparticles. Med Microbiol Immunol 2009; 198:247-56. [DOI: 10.1007/s00430-009-0124-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Indexed: 10/20/2022]
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Liu T, Agar SL, Sha J, Chopra AK. Deletion of Braun lipoprotein gene (lpp) attenuates Yersinia pestis KIM/D27 strain: role of Lpp in modulating host immune response, NF-kappaB activation and cell death. Microb Pathog 2009; 48:42-52. [PMID: 19737605 DOI: 10.1016/j.micpath.2009.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2009] [Revised: 08/25/2009] [Accepted: 09/01/2009] [Indexed: 01/09/2023]
Abstract
The pathogenic species of yersiniae potently blocks immune responses in host cells by using the type III secretion apparatus and its effector proteins. In this study, we characterized potential mechanisms associated with the Braun lipoprotein (Lpp) that contributed to a further attenuation of a pigmentation locus-minus Yersinia pestis KIM/D27 mutant strain and its ability to generate immune responses in mice. The lpp gene encodes one of the major outer membrane lipoproteins that is involved in inflammatory responses and septic shock. We found that sera and splenocytes from Deltalpp mutant-immunized mice, when transferred to naïve animals, provided protection to the latter against challenge with a lethal dose of the Y. pestis parental strain. Further, the Deltalpp mutant promoted ex vivo a significantly higher interleukin (IL)-2 and interferon-gamma production from T cells of immunized mice, when compared to those from animals infected with the sub-lethal dose of the parental Y. pestis KIM/D27 strain. Likewise, murine primary macrophages infected with the mutant, when compared to those infected with the parental strain in vitro, produced significantly higher IL-12 levels. Importantly, increased nuclear factor-kappa B activation and decreased apoptosis were noted in splenocytes and primary macrophages of mice challenged with the Deltalpp mutant, when compared to those in animals infected with the parental Y. pestis KIM/D27 strain. Finally, significantly higher levels of antibodies specific for the parental Y. pestis antigens were developed in mice first immunized with the Deltalpp mutant and then challenged with the parental strain, compared to the antibody levels in animals that were immunized and then infected with the parental KIM/D27 strain. To our knowledge, this is the first report of a mechanistic basis for attenuation and immunological responses associated with deletion of the lpp gene from the Y. pestis KIM/D27 strain.
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Affiliation(s)
- Tie Liu
- Department of Microbiology & Immunology, Medical Research Building, University of Texas Medical Branch, Galveston, TX 77555-1070, USA
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Bergsbaken T, Cookson BT. Innate immune response during Yersinia infection: critical modulation of cell death mechanisms through phagocyte activation. J Leukoc Biol 2009; 86:1153-8. [PMID: 19734471 DOI: 10.1189/jlb.0309146] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Yersinia pestis, the etiological agent of plague, is one of the most deadly pathogens on our planet. This organism shares important attributes with its ancestral progenitor, Yersinia pseudotuberculosis, including a 70-kb virulence plasmid, lymphotropism during growth in the mammalian host, and killing of host macrophages. Infections with both organisms are biphasic, where bacterial replication occurs initially with little inflammation, followed by phagocyte influx, inflammatory cytokine production, and tissue necrosis. During infection, plasmid-encoded attributes facilitate bacterial-induced macrophage death, which results from two distinct processes and corresponds to the inflammatory crescendo observed in vivo: Naïve cells die by apoptosis (noninflammatory), and later in infection, activated macrophages die by pyroptosis (inflammatory). The significance of this redirected cell death for the host is underscored by the importance of phagocyte activation for immunity to Yersinia and the protective role of pyroptosis during host responses to anthrax lethal toxin and infections with Francisella, Legionella, Pseudomonas, and Salmonella. The similarities of Y. pestis and Y. pseudotuberculosis, including conserved, plasmid-encoded functions inducing at least two distinct mechanisms of cell death, indicate that comparative studies are revealing about their critical pathogenic mechanism(s) and host innate immune responses during infection. Validation of this idea and evidence of similar interactions with the host immune system are provided by Y. pseudotuberculosis-priming, cross-protective immunity against Y. pestis. Despite these insights, additional studies indicate much remains to be understood concerning effective host responses against Yersinia, including chromosomally encoded attributes that also contribute to bacterial evasion and modulation of innate and adaptive immune responses.
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Affiliation(s)
- Tessa Bergsbaken
- Department of Microbiology, University of Washington, Seattle, WA, USA
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The role of relA and spoT in Yersinia pestis KIM5 pathogenicity. PLoS One 2009; 4:e6720. [PMID: 19701461 PMCID: PMC2726946 DOI: 10.1371/journal.pone.0006720] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Accepted: 07/20/2009] [Indexed: 01/17/2023] Open
Abstract
The ppGpp molecule is part of a highly conserved regulatory system for mediating the growth response to various environmental conditions. This mechanism may represent a common strategy whereby pathogens such as Yersinia pestis, the causative agent of plague, regulate the virulence gene programs required for invasion, survival and persistence within host cells to match the capacity for growth. The products of the relA and spoT genes carry out ppGpp synthesis. To investigate the role of ppGpp on growth, protein synthesis, gene expression and virulence, we constructed a ΔrelA ΔspoT Y. pestis mutant. The mutant was no longer able to synthesize ppGpp in response to amino acid or carbon starvation, as expected. We also found that it exhibited several novel phenotypes, including a reduced growth rate and autoaggregation at 26°C. In addition, there was a reduction in the level of secretion of key virulence proteins and the mutant was>1,000-fold less virulent than its wild-type parent strain. Mice vaccinated subcutaneously (s.c.) with 2.5×104 CFU of the ΔrelA ΔspoT mutant developed high anti-Y. pestis serum IgG titers, were completely protected against s.c. challenge with 1.5×105 CFU of virulent Y. pestis and partially protected (60% survival) against pulmonary challenge with 2.0×104 CFU of virulent Y. pestis. Our results indicate that ppGpp represents an important virulence determinant in Y. pestis and the ΔrelA ΔspoT mutant strain is a promising vaccine candidate to provide protection against plague.
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238
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Maia JML, Monnazzi LGS, Medeiros BMM. Role of Yersinia pseudotuberculosis outer proteins (Yops) in murine humoral immune response. Folia Microbiol (Praha) 2009; 54:239-45. [PMID: 19649742 DOI: 10.1007/s12223-009-0038-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Revised: 02/12/2009] [Indexed: 11/28/2022]
Abstract
The infection of mice with the wild-type (WT) strain of Y. pseudotuberculosis did not induce polyclonal activation of B lymphocytes. Suppression in the production of certain isotypes of Ig was observed, provoked mainly by YopH, YopJ and YpkA. The WT strain induced a progressive increase in the serum-specific IgG, which peaked after 4 weeks after infection, IgM being produced only after 1 week. Autoantibodies against phosphorylcholine, myelin, thyroglobulin and cardiolipin could be detected in the serum of mice infected with the WT strain. The infection of mice provoked suppression in the production of immunoglobulins by splenic B cells and that YopH, YopJ and YpkA must be involved here.
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Affiliation(s)
- J M L Maia
- Department of Biological Sciences, School of Pharmaceutical Sciences, São Paulo State University, SP, Brazil
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239
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DiMezzo TL, Ruthel G, Brueggemann EE, Hines HB, Ribot WJ, Chapman CE, Powell BS, Welkos SL. In vitro intracellular trafficking of virulence antigen during infection by Yersinia pestis. PLoS One 2009; 4:e6281. [PMID: 19609450 PMCID: PMC2707630 DOI: 10.1371/journal.pone.0006281] [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: 01/29/2009] [Accepted: 06/03/2009] [Indexed: 11/27/2022] Open
Abstract
Yersinia pestis, the causative agent of plague, encodes several essential virulence factors on a 70 kb plasmid, including the Yersinia outer proteins (Yops) and a multifunctional virulence antigen (V). V is uniquely able to inhibit the host immune response; aid in the expression, secretion, and injection of the cytotoxic Yops via a type III secretion system (T3SS)-dependent mechanism; be secreted extracellularly; and enter the host cell by a T3SS-independent mechanism, where its activity is unknown. To elucidate the intracellular trafficking and target(s) of V, time-course experiments were performed with macrophages (MΦs) infected with Y. pestis or Y. pseudotuberculosis at intervals from 5 min to 6 h. The trafficking pattern was discerned from results of parallel microscopy, immunoblotting, and flow cytometry experiments. The MΦs were incubated with fluorescent or gold conjugated primary or secondary anti-V (antibodies [Abs]) in conjunction with organelle-associated Abs or dyes. The samples were observed for co-localization by immuno-fluorescence and electron microscopy. For fractionation studies, uninfected and infected MΦs were lysed and subjected to density gradient centrifugation coupled with immunoblotting with Abs to V or to organelles. Samples were also analyzed by flow cytometry after lysis and dual-staining with anti-V and anti-organelle Abs. Our findings indicate a co-localization of V with (1) endosomal proteins between 10–45 min of infection, (2) lysosomal protein(s) between 1–2 h of infection, (3) mitochondrial proteins between 2.5–3 h infection, and (4) Golgi protein(s) between 4–6 h of infection. Further studies are being performed to determine the specific intracellular interactions and role in pathogenesis of intracellularly localized V.
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Affiliation(s)
- Tracy L. DiMezzo
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Maryland, United States of America
| | - Gordon Ruthel
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Maryland, United States of America
| | - Ernst E. Brueggemann
- Integrated Toxicology, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Maryland, United States of America
| | - Harry B. Hines
- Integrated Toxicology, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Maryland, United States of America
| | - Wilson J. Ribot
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Maryland, United States of America
| | - Carol E. Chapman
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Maryland, United States of America
| | - Bradford S. Powell
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Maryland, United States of America
| | - Susan L. Welkos
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Maryland, United States of America
- * E-mail:
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240
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Serruto D, Spadafina T, Scarselli M, Bambini S, Comanducci M, Höhle S, Kilian M, Veiga E, Cossart P, Oggioni MR, Savino S, Ferlenghi I, Taddei AR, Rappuoli R, Pizza M, Masignani V, Aricò B. HadA is an atypical new multifunctional trimeric coiled-coil adhesin ofHaemophilus influenzaebiogroupaegyptius, which promotes entry into host cells. Cell Microbiol 2009; 11:1044-63. [DOI: 10.1111/j.1462-5822.2009.01306.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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241
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Prediction of type III secretion signals in genomes of gram-negative bacteria. PLoS One 2009; 4:e5917. [PMID: 19526054 PMCID: PMC2690842 DOI: 10.1371/journal.pone.0005917] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Accepted: 05/15/2009] [Indexed: 01/03/2023] Open
Abstract
Background Pathogenic bacteria infecting both animals as well as plants use various mechanisms to transport virulence factors across their cell membranes and channel these proteins into the infected host cell. The type III secretion system represents such a mechanism. Proteins transported via this pathway (“effector proteins”) have to be distinguished from all other proteins that are not exported from the bacterial cell. Although a special targeting signal at the N-terminal end of effector proteins has been proposed in literature its exact characteristics remain unknown. Methodology/Principal Findings In this study, we demonstrate that the signals encoded in the sequences of type III secretion system effectors can be consistently recognized and predicted by machine learning techniques. Known protein effectors were compiled from the literature and sequence databases, and served as training data for artificial neural networks and support vector machine classifiers. Common sequence features were most pronounced in the first 30 amino acids of the effector sequences. Classification accuracy yielded a cross-validated Matthews correlation of 0.63 and allowed for genome-wide prediction of potential type III secretion system effectors in 705 proteobacterial genomes (12% predicted candidates protein), their chromosomes (11%) and plasmids (13%), as well as 213 Firmicute genomes (7%). Conclusions/Significance We present a signal prediction method together with comprehensive survey of potential type III secretion system effectors extracted from 918 published bacterial genomes. Our study demonstrates that the analyzed signal features are common across a wide range of species, and provides a substantial basis for the identification of exported pathogenic proteins as targets for future therapeutic intervention. The prediction software is publicly accessible from our web server (www.modlab.org).
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242
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Zeng G, Chen J, Zhong L, Wang R, Jiang L, Cai J, Yan L, Huang D, Chen CY, Chen ZW. NSOM- and AFM-based nanotechnology elucidates nano-structural and atomic-force features of a Y. pestis V immunogen-containing particle vaccine capable of eliciting robust response. Proteomics 2009; 9:1538-47. [PMID: 19253301 DOI: 10.1002/pmic.200800528] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
It is postulated that unique nanoscale proteomic features of immunogen on vaccine particles may determine immunogen-packing density, stability, specificity, and pH-sensitivity on the vaccine particle surface and thus impact the vaccine-elicited immune responses. To test this presumption, we employed near-filed scanning optical microscopy (NSOM)- and atomic force microscopy (AFM)-based nanotechnology to study nano-structural and single-molecule force bases of Yersinia pestis (Y. pestis) V immunogen fused with protein anchor (V-PA) loaded on gram positive enhancer matrix (GEM) vaccine particles. Surprisingly, the single-molecule sensitive NSOM revealed that approximately 90% of V-PA immunogen molecules were packed as high-density nanoclusters on GEM particle. AFM-based single-molecule force analyses indicated a highly stable and specific binding between V-PA and GEM at the physiological pH. In contrast, this specific binding was mostly abrogated at the acidic pH equivalent to the biochemical pH in phagolysosomes of antigen-presenting-cells in which immunogen protein is processed for antigen presentation. Intranasal mucosal vaccination of mice with such immunogen loaded on vaccine particles elicited robust antigen-specific immune response. This study indicated that high-density, high-stability, specific, and immunological pH-responsive loading of immunogen nanoclusters on vaccine particles could readily be presented to the immune system for induction of strong antigen-specific immune responses.
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Affiliation(s)
- Gucheng Zeng
- Department of Microbiology and Immunology, University of Illinois, Chicago, IL 60612, USA
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243
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Schmid A, Neumayer W, Trülzsch K, Israel L, Imhof A, Roessle M, Sauer G, Richter S, Lauw S, Eylert E, Eisenreich W, Heesemann J, Wilharm G. Cross-talk between type three secretion system and metabolism in Yersinia. J Biol Chem 2009; 284:12165-77. [PMID: 19244229 DOI: 10.1074/jbc.m900773200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Pathogenic yersiniae utilize a type three secretion system (T3SS) to inject Yop proteins into host cells in order to undermine their immune response. YscM1 and YscM2 proteins have been reported to be functionally equivalent regulators of the T3SS in Yersinia enterocolitica. Here, we show by affinity purification, native gel electrophoresis and small angle x-ray scattering that both YscM1 and YscM2 bind to phosphoenolpyruvate carboxylase (PEPC) of Y. enterocolitica. Under in vitro conditions, YscM1, but not YscM2, was found to inhibit PEPC with an apparent IC(50) of 4 mum (K(i) = 1 mum). To analyze the functional roles of PEPC, YscM1, and YscM2 in Yop-producing bacteria, cultures of Y. enterocolitica wild type and mutants defective in the formation of PEPC, YscM1, or YscM2, respectively, were grown under low calcium conditions in the presence of [U-(13)C(6)]glucose. The isotope compositions of secreted Yop proteins and nine amino acids from cellular proteins were analyzed by mass spectrometry. The data indicate that a considerable fraction of oxaloacetate used as precursor for amino acids was derived from [(13)C(3)]phosphoenolpyruvate by the catalytic action of PEPC in the wild-type strain but not in the PEPC(-) mutant. The data imply that PEPC is critically involved in replenishing the oxaloacetate pool in the citrate cycle under virulence conditions. In the YscM1(-) and YscM2(-) mutants, increased rates of pyruvate formation via glycolysis or the Entner-Doudoroff pathway, of oxaloacetate formation via the citrate cycle, and of amino acid biosynthesis suggest that both regulators trigger the central metabolism of Y. enterocolitica. We propose a "load-and-shoot cycle" model to account for the cross-talk between T3SS and metabolism in pathogenic yersiniae.
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Affiliation(s)
- Annika Schmid
- Department of Bacteriology, Max von Pettenkofer-Institute for Hygiene and Medical Microbiology, Pettenkoferstrasse 9a, D-80336 Munich, Germany
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Cerovic V, McDonald V, Nassar MA, Paulin SM, Macpherson GG, Milling SWF. New insights into the roles of dendritic cells in intestinal immunity and tolerance. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 272:33-105. [PMID: 19121816 DOI: 10.1016/s1937-6448(08)01602-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Dendritic cells (DCs) play a critical key role in the initiation of immune responses to pathogens. Paradoxically, they also prevent potentially damaging immune responses being directed against the multitude of harmless antigens, to which the body is exposed daily. These roles are particularly important in the intestine, where only a single layer of epithelial cells provides a barrier against billions of commensal microorganisms, pathogens, and food antigens, over a huge surface area. In the intestine, therefore, DCs are required to perform their dual roles very efficiently to protect the body from the dual threats of invading pathogens and unwanted inflammatory reactions. In this review, we first describe the biology of DCs and their interactions with other cells types, paying particular attention to intestinal DCs. We, then, examine the ways in which this biology may become misdirected, resulting in inflammatory bowel disease. Finally, we discuss how DCs potentiate immune responses against viral, bacterial, parasitic infections, and their importance in the pathogenesis of prion diseases. We, therefore, provide an overview of the complex cellular interactions that affect intestinal DCs and control the balance between immunity and tolerance.
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Affiliation(s)
- Vuk Cerovic
- Sir William Dunn School of Pathology, Oxford University, Oxford, United Kingdom
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245
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de la Puerta ML, Trinidad AG, Rodríguez MDC, Bogetz J, Sánchez Crespo M, Mustelin T, Alonso A, Bayón Y. Characterization of new substrates targeted by Yersinia tyrosine phosphatase YopH. PLoS One 2009; 4:e4431. [PMID: 19221593 PMCID: PMC2637541 DOI: 10.1371/journal.pone.0004431] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Accepted: 12/17/2008] [Indexed: 12/24/2022] Open
Abstract
YopH is an exceptionally active tyrosine phosphatase that is essential for virulence of Yersinia pestis, the bacterium causing plague. YopH breaks down signal transduction mechanisms in immune cells and inhibits the immune response. Only a few substrates for YopH have been characterized so far, for instance p130Cas and Fyb, but in view of YopH potency and the great number of proteins involved in signalling pathways it is quite likely that more proteins are substrates of this phosphatase. In this respect, we show here YopH interaction with several proteins not shown before, such as Gab1, Gab2, p85, and Vav and analyse the domains of YopH involved in these interactions. Furthermore, we show that Gab1, Gab2 and Vav are not dephosphorylated by YopH, in contrast to Fyb, Lck, or p85, which are readily dephosphorylated by the phosphatase. These data suggests that YopH might exert its actions by interacting with adaptors involved in signal transduction pathways, what allows the phosphatase to reach and dephosphorylate its susbstrates.
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Affiliation(s)
| | - Antonio G. Trinidad
- Instituto de Biología y Genética Molecular, CSIC-Universidad de Valladolid, Valladolid, Spain
| | | | - Jori Bogetz
- Program of Inflammation, Inflammatory and Infectious Disease Center, and Program of Signal Transduction, Burnham Institute for Medical Research, La Jolla, California, United States of America
| | - Mariano Sánchez Crespo
- Instituto de Biología y Genética Molecular, CSIC-Universidad de Valladolid, Valladolid, Spain
| | - Tomas Mustelin
- Program of Inflammation, Inflammatory and Infectious Disease Center, and Program of Signal Transduction, Burnham Institute for Medical Research, La Jolla, California, United States of America
| | - Andrés Alonso
- Instituto de Biología y Genética Molecular, CSIC-Universidad de Valladolid, Valladolid, Spain
| | - Yolanda Bayón
- Instituto de Biología y Genética Molecular, CSIC-Universidad de Valladolid, Valladolid, Spain
- * E-mail:
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246
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Magagnoli C, Bardotti A, De Conciliis G, Galasso R, Tomei M, Campa C, Pennatini C, Cerchioni M, Fabbri B, Giannini S, Mattioli GL, Biolchi A, D'Ascenzi S, Helling F. Structural organization of NadADelta(351-405), a recombinant MenB vaccine component, by its physico-chemical characterization at drug substance level. Vaccine 2009; 27:2156-70. [PMID: 19356620 DOI: 10.1016/j.vaccine.2009.01.099] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 01/13/2009] [Accepted: 01/22/2009] [Indexed: 12/27/2022]
Abstract
The physico-chemical characterization of NadADelta(351-405), a recombinant protein discovered by reverse vaccinology, component of a candidate vaccine against Neisseria meningitidis serotype B is presented. Analytical methods like mass spectrometry, electrophoresis, optical spectroscopy and SEC-MALLS have been applied to unveil the structure of NadADelta(351-405), and to evaluate Product-Related Substances. Moreover, analysis of the protein after intentional denaturation has been applied in order to challenge the chosen methods and to determine their appropriateness and specificity. All the obtained results were inserted in a model allowing in-depth understanding of the antigen NadADelta(351-405): it is present in solution as a homo-trimer, retaining a high percentage of alpha-helix secondary structure, and able to reassemble from monomeric subunits after thermal denaturation; this structural organization is consistent with that foreseen for MenB NadA (Neisseria Adhesin A). The analytical data sets produced during process development for clinical phases I-III material confirm product quality and manufacturing consistency.
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247
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Synchronous gene expression of the Yersinia enterocolitica Ysa type III secretion system and its effectors. J Bacteriol 2009; 191:1816-26. [PMID: 19124573 DOI: 10.1128/jb.01402-08] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Type III secretion systems (T3SSs) are complex units that consist of many proteins. Often the proteins are encoded as a cohesive unit on virulence plasmids, but several systems have their various components dispersed around the chromosome. The Yersinia enterocolitica Ysa T3SS is such a system, where the apparatus genes, some regulatory genes, and four genes encoding secreted proteins (ysp genes) are contained in a single locus. The remaining ysp genes and at least one additional regulator are found elsewhere on the chromosome. Expression of ysa genes requires conditions of high ionic strength, neutral/basic pH, and low temperatures (26 degrees C) and is stimulated by exposure to solid surfaces. The AraC-like regulator YsaE and the dual-function chaperone/regulator SycB are required to stimulate the sycB promoter, which transcribes sycB and probably yspBCDA as well. The putative phosphorelay proteins YsrRS (located at the distal end of the ysa locus) and RcsB, the response regulator of the RcsBCD phosphorelay system, are required to initiate transcription at the ysaE promoter, which drives transcription of many apparatus genes. In this work, we sought to determine which ysp genes were coordinately regulated with the genes within the ysa locus. We found that six unlinked ysp genes responded to NaCl and required YsaE/SycB, YsrRS, and RcsB for expression. Three ysp genes had unique patterns, one of which was unaffected by all elements tested except NaCl. Thus, while the ysp genes were likely to have been acquired independently, most have acquired a synchronous regulatory pattern.
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248
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The Three Bears and Virulence-Associated Plasmids in the Genus Yersinia. MICROBIAL MEGAPLASMIDS 2009. [DOI: 10.1007/978-3-540-85467-8_8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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249
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The Yersinia pestis caf1M1A1 fimbrial capsule operon promotes transmission by flea bite in a mouse model of bubonic plague. Infect Immun 2008; 77:1222-9. [PMID: 19103769 DOI: 10.1128/iai.00950-08] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Plague is a zoonosis transmitted by fleas and caused by the gram-negative bacterium Yersinia pestis. During infection, the plasmidic caf1M1A1 operon that encodes the Y. pestis F1 protein capsule is highly expressed, and anti-F1 antibodies are protective. Surprisingly, the capsule is not required for virulence after injection of cultured bacteria, even though it is an antiphagocytic factor and capsule-deficient Y. pestis strains are rarely isolated. We found that a caf-negative Y. pestis mutant was not impaired in either flea colonization or virulence in mice after intradermal inoculation of cultured bacteria. In contrast, absence of the caf operon decreased bubonic plague incidence after a flea bite. Successful development of plague in mice infected by flea bite with the caf-negative mutant required a higher number of infective bites per challenge. In addition, the mutant displayed a highly autoaggregative phenotype in infected liver and spleen. The results suggest that acquisition of the caf locus via horizontal transfer by an ancestral Y. pestis strain increased transmissibility and the potential for epidemic spread. In addition, our data support a model in which atypical caf-negative strains could emerge during climatic conditions that favor a high flea burden. Human infection with such strains would not be diagnosed by the standard clinical tests that detect F1 antibody or antigen, suggesting that more comprehensive surveillance for atypical Y. pestis strains in plague foci may be necessary. The results also highlight the importance of studying Y. pestis pathogenesis in the natural context of arthropod-borne transmission.
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250
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The Yersinia pestis Ail protein mediates binding and Yop delivery to host cells required for plague virulence. Infect Immun 2008; 77:825-36. [PMID: 19064637 DOI: 10.1128/iai.00913-08] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Although adhesion to host cells is a critical step in the delivery of cytotoxic Yop proteins by Yersinia pestis, the mechanism has not been defined. To identify adhesins critical for Yop delivery, we initiated two transposon mutagenesis screens using the mariner transposon. To avoid redundant cell binding activities, we initiated the screen with a strain deleted for two known adhesins, pH 6 antigen and the autotransporter, YapC, as well as the Caf1 capsule, which is known to obscure some adhesins. The mutants that emerged contained insertions within the ail (attachment and invasion locus) gene of Y. pestis. A reconstructed mutant with a single deletion in the ail locus (y1324) was severely defective for delivery of Yops to HEp-2 human epithelial cells and significantly defective for delivery of Yops to THP-1 human monocytes. Specifically, the Yop delivery defect was apparent when cell rounding and translocation of an ELK-tagged YopE derivative into host cells were monitored. Although the ail mutant showed only a modest decrease in cell binding capacity in vitro, the KIM5 Deltaail mutant exhibited a >3,000-fold-increased 50% lethal dose in mice. Mice infected with the Deltaail mutant also had 1,000-fold fewer bacteria in their spleens, livers, and lungs 3 days after infection than did those infected with the parental strain, KIM5. Thus, the Ail protein is critical for both Y. pestis type III secretion in vitro and infection in mice.
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