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Holzapfel M, Bonhomme D, Cagliero J, Vernel-Pauillac F, Fanton d'Andon M, Bortolussi S, Fiette L, Goarant C, Wunder EA, Picardeau M, Ko AI, Werling D, Matsui M, Boneca IG, Werts C. Escape of TLR5 Recognition by Leptospira spp.: A Rationale for Atypical Endoflagella. Front Immunol 2020; 11:2007. [PMID: 32849665 PMCID: PMC7431986 DOI: 10.3389/fimmu.2020.02007] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/24/2020] [Indexed: 12/26/2022] Open
Abstract
Leptospira (L.) interrogans are invasive bacteria responsible for leptospirosis, a worldwide zoonosis. They possess two periplasmic endoflagellae that allow their motility. L. interrogans are stealth pathogens that escape the innate immune recognition of the NOD-like receptors NOD1/2, and the human Toll-like receptor (TLR)4, which senses peptidoglycan and lipopolysaccharide (LPS), respectively. TLR5 is another receptor of bacterial cell wall components, recognizing flagellin subunits. To study the contribution of TLR5 in the host defense against leptospires, we infected WT and TLR5 deficient mice with pathogenic L. interrogans and tracked the infection by in vivo live imaging of bioluminescent bacteria or by qPCR. We did not identify any protective or inflammatory role of murine TLR5 for controlling pathogenic Leptospira. Likewise, subsequent in vitro experiments showed that infections with different live strains of L. interrogans and L. biflexa did not trigger TLR5 signaling. However, unexpectedly, heat-killed bacteria stimulated human and bovine TLR5, but did not, or barely induced stimulation via murine TLR5. Abolition of TLR5 recognition required extensive boiling time of the bacteria or proteinase K treatment, showing an unusual high stability of the leptospiral flagellins. Interestingly, after using antimicrobial peptides to destabilize live leptospires, we detected TLR5 activity, suggesting that TLR5 could participate in the fight against leptospires in humans or cattle. Using different Leptospira strains with mutations in the flagellin proteins, we further showed that neither FlaA nor Fcp participated in the recognition by TLR5, suggesting a role for the FlaB. FlaB have structural homology to Salmonella FliC, and possess conserved residues important for TLR5 activation, as shown by in silico analyses. Accordingly, we found that leptospires regulate the expression of FlaB mRNA according to the growth phase in vitro, and that infection with L. interrogans in hamsters and in mice downregulated the expression of the FlaB, but not the FlaA subunits. Altogether, in contrast to different bacteria that modify their flagellin sequences to escape TLR5 recognition, our study suggests that the peculiar central localization and stability of the FlaB monomers in the periplasmic endoflagellae, associated with the downregulation of FlaB subunits in hosts, constitute an efficient strategy of leptospires to escape the TLR5 recognition and the induced immune response.
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Affiliation(s)
- Marion Holzapfel
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
| | - Delphine Bonhomme
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France.,Sorbonne Paris Cité, Université de Paris, Paris, France
| | - Julie Cagliero
- Institut Pasteur de Nouvelle Calédonie, Immunity and Inflammation Group, Institut Pasteur International Network, Noumea, France
| | - Frédérique Vernel-Pauillac
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
| | - Martine Fanton d'Andon
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
| | - Sophia Bortolussi
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
| | - Laurence Fiette
- Unité Histopathologie Humaine et Modèles Animaux, Institut Pasteur, Paris, France
| | - Cyrille Goarant
- Leptospirosis Research and Expertise Unit, Institut Pasteur International Network, Institut Pasteur de Nouvelle Calédonie, Noumea, France
| | - Elsio A Wunder
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, Brazil.,Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
| | | | - Albert I Ko
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, Brazil.,Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
| | - Dirk Werling
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | - Mariko Matsui
- Institut Pasteur de Nouvelle Calédonie, Immunity and Inflammation Group, Institut Pasteur International Network, Noumea, France
| | - Ivo G Boneca
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
| | - Catherine Werts
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
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Reference genes for real-time RT-PCR expression studies in an Antarctic Pseudomonas exposed to different temperature conditions. Extremophiles 2019; 23:625-633. [DOI: 10.1007/s00792-019-01109-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 06/17/2019] [Indexed: 12/21/2022]
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Ma W, Jia J, Huang X, Xie W, Zhang X, Tang J, Lin C, Zhao L, Fang P. Stable isotope labelling by amino acids in cell culture (SILAC) applied to quantitative proteomics of Edwardsiella tarda ATCC 15947 under prolonged cold stress. Microb Pathog 2018; 125:12-19. [PMID: 30201590 DOI: 10.1016/j.micpath.2018.09.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 09/01/2018] [Accepted: 09/05/2018] [Indexed: 01/15/2023]
Abstract
Edwardsiella tarda poses a threat to human health and has resulted in enormous economic losses in aquaculture. Low temperatures are usually applied to contain the growth of this microorganism. In this study, stable isotope labelling by amino acids in cell culture (SILAC) was used to conduct comparative proteomic quantitation of E. tarda ATCC 15947 under cold stress for two weeks. We identified 1391 proteins, of which 898 were quantifiable. Of these, 72 proteins were upregulated and 164 were downregulated in response to cold stress. Even though E. tarda ATCC 15947 is not a psychrophile, several key proteins related to DNA synthesis and transcription were significantly upregulated. Additionally, proteins related to haemolytic activities and gluconeogenesis were upregulated, even though E. tarda ATCC 15497 is considered non-virulent in aquaculture. This study therefore delineated the specific proteomic response of this E. tarda ATCC 15947 to prolonged cold stress.
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Affiliation(s)
- Weixing Ma
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China; Qingdao University of Science and Technology, No. 53, Zhengzhou Road, Qingdao, 266042, China
| | - Juntao Jia
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China.
| | - Xiaohua Huang
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China
| | - Wancui Xie
- Qingdao University of Science and Technology, No. 53, Zhengzhou Road, Qingdao, 266042, China
| | - Xiaoliang Zhang
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China
| | - Jing Tang
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China
| | - Chao Lin
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China
| | - Liqing Zhao
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China
| | - Peipei Fang
- Shandong Entry-Exit Inspection and Quarantine Bureau, No. 70, Qutangxia Road, Qingdao, 266002, China
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Cao Y, Xie X, Zhang W, Wu D, Tu C. Low-dose Norfloxacin-treated leptospires induce less IL-1β release in J774A.1 cells following discrepant leptospiral gene expression. Microb Pathog 2018; 119:125-130. [DOI: 10.1016/j.micpath.2018.03.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 03/16/2018] [Accepted: 03/19/2018] [Indexed: 02/07/2023]
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The role of apitoxin in alleviating propionic acid-induced neurobehavioral impairments in rat pups: The expression pattern of Reelin gene. Biomed Pharmacother 2017. [DOI: 10.1016/j.biopha.2017.06.034] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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The EbpA-RpoN Regulatory Pathway of the Pathogen Leptospira interrogans Is Essential for Survival in the Environment. Appl Environ Microbiol 2017; 83:AEM.02377-16. [PMID: 27864172 DOI: 10.1128/aem.02377-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 11/14/2016] [Indexed: 01/01/2023] Open
Abstract
Leptospira interrogans is the agent of leptospirosis, a reemerging zoonotic disease. It is transmitted to humans through environmental surface waters contaminated by the urine of mammals chronically infected by pathogenic strains able to survive in water for long periods. Little is known about the regulatory pathways underlying environmental sensing and host adaptation of L. interrogans during its enzootic cycle. This study identifies the EbpA-RpoN regulatory pathway in L. interrogans In this pathway, EbpA, a σ54 activator and putative prokaryotic enhancer-binding protein (EBP), and the alternative sigma factor RpoN (σ54) control expression of at least three genes, encoding AmtB (an ammonium transport protein) and two proteins of unknown function. Electrophoresis mobility shift assay demonstrated that recombinant RpoN and EbpA bind to the promoter region and upstream of these three identified genes, respectively. Genetic disruption of ebpA in L. interrogans serovar Manilae virtually abolished expression of the three genes, including amtB in two independent ebpA mutants. Complementation of the ebpA mutant restored expression of these genes. Intraperitoneal inoculation of gerbils with the ebpA mutant did not affect mortality. However, the ebpA mutant had decreased cell length in vitro and had a significantly lowered cell density at stationary phase when grown with l-alanine as the sole nitrogen source. Furthermore, the ebpA mutant has dramatically reduced long-term survival ability in water. Together, these studies identify a regulatory pathway, the EbpA-RpoN pathway, that plays an important role in the zoonotic cycle of L. interrogans IMPORTANCE: Leptospirosis is a reemerging disease with global importance. However, our understanding of gene regulation of the spirochetal pathogen Leptospira interrogans is still in its infancy, largely due to the lack of robust tools for genetic manipulation of this spirochete. Little is known about how the pathogen achieves its long-term survival in the aquatic environment. By utilizing bioinformatic, genetic, and biochemical methods, we discovered a regulatory pathway in L. interrogans, the EbpA-RpoN pathway, and demonstrated that this pathway plays an important role in environmental survival of this pathogen.
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Tao Z, Zhou T, Zhou S, Wang G. Temperature-regulated expression of type VI secretion systems in fish pathogen Pseudomonas plecoglossicida revealed by comparative secretome analysis. FEMS Microbiol Lett 2016; 363:fnw261. [PMID: 27974393 DOI: 10.1093/femsle/fnw261] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 09/10/2016] [Accepted: 11/10/2016] [Indexed: 11/14/2022] Open
Abstract
Pseudomonas plecoglossicida is a facultative fish pathogen. Recent studies showed that P. plecoglossicida infection in fish was associated with temperature. The aim of this study was to compare the secretomes of P. plecoglossicida cultured in vitro at representative temperatures for pathogenic (20°C) and less pathogenic (30°C) phenotypes. Thirteen proteins in the culture supernatants of P. plecoglossicida showed significant difference in abundance at 20 vs. 30°C. Four proteins were strongly increased at 20°C, including two hemolysin co-regulated proteins (Hcp) that are part of the bacterial type VI secretion system (T6SS), flagellin and an unknown protein. Immunoblot analysis verified the induced secretion of Hcps at 20°C. Furthermore, the upregulation of Hcps at 20°C was confirmed at transcriptional level by RT-qPCR analysis, which also demonstrated the induction of expression of other T6SS-related genes at 20°C. Taken together, we demonstrate the presence of two functionally active T6SS proteins in fish pathogenic P. plecoglossicida strains, as evidenced by the secretion of the T6SS substrate Hcp, the production of which were found to be controlled by temperature. Our findings also support efforts to develop vaccines targeting secreted virulence factors as prophylactic strategies for diseases in fish caused by P. plecoglossicida.
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Affiliation(s)
- Zhen Tao
- School of Marine Science, Ningbo University, 818 Feng-Hua Road, Ningbo, Zhejiang 315211, China
| | - Tao Zhou
- School of Marine Science, Ningbo University, 818 Feng-Hua Road, Ningbo, Zhejiang 315211, China
| | - Suming Zhou
- School of Marine Science, Ningbo University, 818 Feng-Hua Road, Ningbo, Zhejiang 315211, China
| | - Guoliang Wang
- School of Marine Science, Ningbo University, 818 Feng-Hua Road, Ningbo, Zhejiang 315211, China
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Multiple Posttranslational Modifications of Leptospira biflexa Proteins as Revealed by Proteomic Analysis. Appl Environ Microbiol 2015; 82:1183-1195. [PMID: 26655756 DOI: 10.1128/aem.03056-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 12/01/2015] [Indexed: 12/12/2022] Open
Abstract
The saprophyte Leptospira biflexa is an excellent model for studying the physiology of the medically important Leptospira genus, the pathogenic members of which are more recalcitrant to genetic manipulation and have significantly slower in vitro growth. However, relatively little is known regarding the proteome of L. biflexa, limiting its utility as a model for some studies. Therefore, we have generated a proteomic map of both soluble and membrane-associated proteins of L. biflexa during exponential growth and in stationary phase. Using these data, we identified abundantly produced proteins in each cellular fraction and quantified the transcript levels from a subset of these genes using quantitative reverse transcription-PCR (RT-PCR). These proteins should prove useful as cellular markers and as controls for gene expression studies. We also observed a significant number of L. biflexa membrane-associated proteins with multiple isoforms, each having unique isoelectric focusing points. L. biflexa cell lysates were examined for several posttranslational modifications suggested by the protein patterns. Methylation and acetylation of lysine residues were predominately observed in the proteins of the membrane-associated fraction, while phosphorylation was detected mainly among soluble proteins. These three posttranslational modification systems appear to be conserved between the free-living species L. biflexa and the pathogenic species Leptospira interrogans, suggesting an important physiological advantage despite the varied life cycles of the different species.
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Potential impact on kidney infection: a whole-genome analysis of Leptospira santarosai serovar Shermani. Emerg Microbes Infect 2014; 3:e82. [PMID: 26038504 PMCID: PMC4274889 DOI: 10.1038/emi.2014.78] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 09/01/2014] [Accepted: 09/11/2014] [Indexed: 11/21/2022]
Abstract
Leptospira santarosai serovar Shermani is the most frequently encountered
serovar, and it causes leptospirosis and tubulointerstitial nephritis in Taiwan. This
study aims to complete the genome sequence of L. santarosai serovar Shermani
and analyze the transcriptional responses of L. santarosai serovar Shermani
to renal tubular cells. To assemble this highly repetitive genome, we combined reads
that were generated from four next-generation sequencing platforms by using hybrid
assembly approaches to finish two-chromosome contiguous sequences without gaps by
validating the data with optical restriction maps and Sanger sequencing. Whole-genome
comparison studies revealed a 28-kb region containing genes that encode transposases
and hypothetical proteins in L. santarosai serovar Shermani, but this region
is absent in other pathogenic Leptospira spp. We found that lipoprotein gene
expression in both L. santarosai serovar Shermani and L.
interrogans serovar Copenhageni were upregulated upon interaction with renal
tubular cells, and LSS19962, a L. santarosai serovar Shermani-specific gene
within a 28-kb region that encodes hypothetical proteins, was upregulated in L.
santarosai serovar Shermani-infected renal tubular cells. Lipoprotein
expression during leptospiral infection might facilitate the interactions of
leptospires within kidneys. The availability of the whole-genome sequence of L.
santarosai serovar Shermani would make it the first completed sequence of
this species, and its comparison with that of other Leptospira spp. may
provide invaluable information for further studies in leptospiral pathogenesis.
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RETRACTED: ChpK and MazF of the toxin-antitoxin modules are involved in the virulence of Leptospira interrogans during infection. Microbes Infect 2014; 17:34-47. [PMID: 25461800 DOI: 10.1016/j.micinf.2014.10.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 10/27/2014] [Accepted: 10/29/2014] [Indexed: 11/20/2022]
Abstract
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal).
This article has been retracted at the request of the corresponding author and the editorial office of Microbes and Infection. An independent reviewer of the retraction request was also appointed given that one of the authors is the Editor-in- Chief.
For figure 1C, Lanes 1 and 2 appear to share some unexpected similarities, except for the bottom band, which also appear to be the band of interest.
Sections of Figure 2C appear similar to sections of Figure 5D of a paper that had already appeared in Molecular Microbiology, volume 83, issue 5 (2012) 1006-1023. https://doi.org/10.1111/j.1365-2958.2012.07985.x.
In figure 3A, Flow cytograms share identical/similar patterns highlighted in various colours. Peculiarly, some of these patterns can be seen as horizontal rotations of others along the axis that separates different quadrants. (ie red green & purple). Moreover, some quadrants appear to have very high densities of events that are suprisingly limited by quadrant gates (most noticeably quadrants B2 from the second column of panels.
Figure 5A-B it was found that there were duplicated bands were produced.
Figures 5C and 5D, it was found that bands across each individual gel appear identical.
One of the conditions of submission of a paper for publication is that authors declare explicitly that the paper has not been previously published and is not under consideration for publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a misuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process”.
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Kassegne K, Hu W, Ojcius DM, Sun D, Ge Y, Zhao J, Yang XF, Li L, Yan J. Identification of collagenase as a critical virulence factor for invasiveness and transmission of pathogenic Leptospira species. J Infect Dis 2013; 209:1105-15. [PMID: 24277745 DOI: 10.1093/infdis/jit659] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Leptospirosis is a global zoonotic disease. Transmission of Leptospira from animals to humans occurs through contact with water contaminated with leptospire-containing urine of infected animals. However, the molecular basis for the invasiveness of Leptospira and transmission of leptospirosis remains unknown. METHODS Activity of Leptospira interrogans strain Lai colA gene product (ColA) to hydrolyze different collagenic substrates was determined by spectrophotometry. Expression and secretion of ColA during infection were detected by reverse-transcription quantitative polymerase chain reaction and Western blot assay. The colA gene-deleted (ΔcolA) and colA gene-complemented (CΔcolA) mutants were generated to determine the roles of ColA in transcytosis in vitro and virulence in hamsters. RESULTS Recombinant or native ColA hydrolyzed all the tested substrates in which type III collagen was the favorite substrate with 2.16 mg/mL Km and 35.6 h(-)(1) Kcat values. Coincubation of the spirochete with HUVEC or HEK293 cells directly caused the significant elevation of ColA expression and secretion. Compared with wild-type strain, ΔcolA mutant displayed much-attenuated transcytosis through HEK293 and HUVEC monolayers, and less leptospires in blood, lung, liver, kidney and urine and 25-fold-decreased 50% lethal dose and milder histopathological injury in hamsters. CONCLUSIONS The product of colA gene is a collagenase as a crucial virulence factor in the invasiveness and transmission of L. interrogans.
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Affiliation(s)
- Kokouvi Kassegne
- Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, Zhejiang University School of Medicine
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Zhao JF, Chen HH, Ojcius DM, Zhao X, Sun D, Ge YM, Zheng LL, Lin X, Li LJ, Yan J. Identification of Leptospira interrogans phospholipase C as a novel virulence factor responsible for intracellular free calcium ion elevation during macrophage death. PLoS One 2013; 8:e75652. [PMID: 24124502 PMCID: PMC3790881 DOI: 10.1371/journal.pone.0075652] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 08/17/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Leptospira-induced macrophage death has been confirmed to play a crucial role in pathogenesis of leptospirosis, a worldwide zoonotic infectious disease. Intracellular free Ca(2+) concentration ([Ca(2+)]i) elevation induced by infection can cause cell death, but [Ca(2+)]i changes and high [Ca(2+)]i-induced death of macrophages due to infection of Leptospira have not been previously reported. METHODOLOGY/PRINCIPAL FINDINGS We first used a Ca(2+)-specific fluorescence probe to confirm that the infection of L. interrogans strain Lai triggered a significant increase of [Ca(2+)]i in mouse J774A.1 or human THP-1 macrophages. Laser confocal microscopic examination showed that the [Ca(2+)]i elevation was caused by both extracellular Ca(2+) influx through the purinergic receptor, P2X7, and Ca(2+) release from the endoplasmic reticulum, as seen by suppression of [Ca(2+)]i elevation when receptor-gated calcium channels were blocked or P2X7 was depleted. The LB361 gene product of the spirochete exhibited phosphatidylinositol phospholipase C (L-PI-PLC) activity to hydrolyze phosphatidylinositol-4,5-bisphosphate (PIP2) into inositol-1,4,5-trisphosphate (IP3), which in turn induces intracellular Ca(2+) release from endoplasmic reticulum, with the Km of 199 µM and Kcat of 8.566E-5 S(-1). Secretion of L-PI-PLC from the spirochete into supernatants of leptospire-macrophage co-cultures and cytosol of infected macrophages was also observed by Western Blot assay. Lower [Ca(2+)]i elevation was induced by infection with a LB361-deficient leptospiral mutant, whereas transfection of the LB361 gene caused a mild increase in [Ca(2+)]i. Moreover, PI-PLCs (PI-PLC-β3 and PI-PLC-γ1) of the two macrophages were activated by phosphorylation during infection. Flow cytometric detection demonstrated that high [Ca(2+)]i increases induced apoptosis and necrosis of macrophages, while mild [Ca(2+)]i elevation only caused apoptosis. CONCLUSIONS/SIGNIFICANCE This study demonstrated that L. interrogans infection induced [Ca(2+)]i elevation through extracellular Ca(2+) influx and intracellular Ca(2+) release cause macrophage apoptosis and necrosis, and the LB361 gene product was shown to be a novel PI-PLC of L. interrogans responsible for the [Ca(2+)]i elevation.
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Affiliation(s)
- Jing-Fang Zhao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
- Depatment of Clinical Laboratory, Zhejiang Provincial Hospital of Traditional Chinese Medicine, Hangzhou, Zhejiang, P.R. China
| | - Hong-Hu Chen
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - David M. Ojcius
- Health Sciences Research Institute and Department Molecular Cell Biology, University of California Merced, Merced, California, United States of America
| | - Xin Zhao
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - Dexter Sun
- Department of Neurology and Neuroscience, New York Presbyterian Hospital and Hospital for Special Surgery, Cornell University Weill Medical College, New York, New York, United States of America
| | - Yu-Mei Ge
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - Lin-Li Zheng
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - Xu’ai Lin
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - Lan-Juan Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - Jie Yan
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
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Lehmann JS, Fouts DE, Haft DH, Cannella AP, Ricaldi JN, Brinkac L, Harkins D, Durkin S, Sanka R, Sutton G, Moreno A, Vinetz JM, Matthias MA. Pathogenomic inference of virulence-associated genes in Leptospira interrogans. PLoS Negl Trop Dis 2013; 7:e2468. [PMID: 24098822 PMCID: PMC3789758 DOI: 10.1371/journal.pntd.0002468] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 08/23/2013] [Indexed: 11/18/2022] Open
Abstract
Leptospirosis is a globally important, neglected zoonotic infection caused by spirochetes of the genus Leptospira. Since genetic transformation remains technically limited for pathogenic Leptospira, a systems biology pathogenomic approach was used to infer leptospiral virulence genes by whole genome comparison of culture-attenuated Leptospira interrogans serovar Lai with its virulent, isogenic parent. Among the 11 pathogen-specific protein-coding genes in which non-synonymous mutations were found, a putative soluble adenylate cyclase with host cell cAMP-elevating activity, and two members of a previously unstudied ∼15 member paralogous gene family of unknown function were identified. This gene family was also uniquely found in the alpha-proteobacteria Bartonella bacilliformis and Bartonella australis that are geographically restricted to the Andes and Australia, respectively. How the pathogenic Leptospira and these two Bartonella species came to share this expanded gene family remains an evolutionary mystery. In vivo expression analyses demonstrated up-regulation of 10/11 Leptospira genes identified in the attenuation screen, and profound in vivo, tissue-specific up-regulation by members of the paralogous gene family, suggesting a direct role in virulence and host-pathogen interactions. The pathogenomic experimental design here is generalizable as a functional systems biology approach to studying bacterial pathogenesis and virulence and should encourage similar experimental studies of other pathogens.
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Affiliation(s)
- Jason S Lehmann
- Division of Infectious Diseases, Department of Medicine, University of California San Diego School of Medicine, La Jolla, California, United States of America
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14
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Identification and Evaluation of Reference Genes for qRT-PCR Normalization in Ganoderma lucidum. Curr Microbiol 2013; 68:120-6. [DOI: 10.1007/s00284-013-0442-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 07/10/2013] [Indexed: 12/23/2022]
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15
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Leelatanawit R, Klanchui A, Uawisetwathana U, Karoonuthaisiri N. Validation of reference genes for real-time PCR of reproductive system in the black tiger shrimp. PLoS One 2012; 7:e52677. [PMID: 23285145 PMCID: PMC3532477 DOI: 10.1371/journal.pone.0052677] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 11/19/2012] [Indexed: 11/19/2022] Open
Abstract
Gene expression of reproductive system of the black tiger shrimp (Peneaus monodon) has been widely studied to address poor maturation problem in captivity. However, a systematic evaluation of reference genes in quantitative real-time PCR (qPCR) for P. monodon reproductive organs is lacking. In this study, the stability of four potential reference genes (18s rRNA, GAPDH, β-actin, and EF1-α) was examined in the reproductive tissues in various conditions using bioinformatic tools: NormFinder and geNorm. For NormFinder, EF1-α and GAPDH ranked first and second as the most stable genes in testis groups whereas GAPDH and EF1-α were for ovaries from wild-caught broodstock and domesticated groups. EF1-α and β-actin ranked first and second for the eyestalk ablated ovaries. For geNorm, EF1-α and GAPDH had the best stability in all testis and ovaries from domesticated groups whereas EF1-α and β-actin were the best for ovaries from wild-caught and eyestalk ablated groups. Moreover, the expression levels of two well-known reproductive genes, Dmc1 and Vitellogenin, were used to validate these reference genes. When normalized to EF1-α, the expected expression patterns were obtained in all cases. Therefore, this work suggests that EF1-α is more versatile as reference genes in qPCR analysis for reproductive system in P. monodon.
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Affiliation(s)
- Rungnapa Leelatanawit
- Microarray Laboratory, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Klong Luang, Pathumthani, Thailand
| | - Amornpan Klanchui
- Microarray Laboratory, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Klong Luang, Pathumthani, Thailand
| | - Umaporn Uawisetwathana
- Microarray Laboratory, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Klong Luang, Pathumthani, Thailand
| | - Nitsara Karoonuthaisiri
- Microarray Laboratory, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Klong Luang, Pathumthani, Thailand
- * E-mail:
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16
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Wang H, Wu Y, Ojcius DM, Yang XF, Zhang C, Ding S, Lin X, Yan J. Leptospiral hemolysins induce proinflammatory cytokines through Toll-like receptor 2-and 4-mediated JNK and NF-κB signaling pathways. PLoS One 2012; 7:e42266. [PMID: 22870312 PMCID: PMC3411626 DOI: 10.1371/journal.pone.0042266] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 07/02/2012] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Infection with pathogenic Leptospira species causes serious systemic inflammation in patients. Although a few leptospiral proinflammatory molecules have been identified, Leptospira likely encodes other unidentified strong inflammation stimulators. The pathogenic L. interrogans genome encodes numerous putative hemolysin genes. Since hemolysins from other bacteria can cause inflammatory reactions, we hypothesized that leptospiral hemolysins may function as proinflammatory stimulators that contribute to the strong inflammation associated with Leptospira infection. METHODOLOGY/PRINCIPAL FINDINGS We first used cytokine protein microarrays for systematic analysis of serum cytokine profiles in leptospirosis patients and leptospire-infected mice. We found that IL-1β, IL-6 and TNF-α were the main proinflammatory cytokines in the sera of both the patients and the mice. We then analyzed eight putative hemolysins in L. interrogans strain Lai. The results showed that five of them, Sph1, Sph2, Sph3, HlpA and TlyA were secreted and had hemolytic activity. More importantly, these five hemolysins induced the strong production of IL-1β, IL-6 and TNF-α in human and mouse macrophages (although a bit lower in the latter). Furthermore, blockade of TLR2 or TLR4 with either antibodies or inhibitors of the NF-κB or JNK signaling pathways significantly reduced the production of hemolysin-induced IL-1β, IL-6 and TNF-α. Macrophages isolated from TLR2-, TLR4-or double TLR2-and 4-deficient mice also confirmed that the leptospiral hemolysins that induce proinflammatory cytokines are both TLR2-and TLR4-dependent. CONCLUSIONS/SIGNIFICANCE Our findings demonstrate that L. interrogans secretes many hemolysins that function as powerful inducers of proinflammatory cytokines through both TLR2-and TLR4-dependent JNK and NF-κB pathways.
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Affiliation(s)
- Huan Wang
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yifei Wu
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - David M. Ojcius
- Health Sciences Research Institute and Molecular Cell Biology, University of California, Merced, California, United States of America
| | - X. Frank Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Chenglin Zhang
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Shibiao Ding
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xu’ai Lin
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- * E-mail: (JY); (XL)
| | - Jie Yan
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- * E-mail: (JY); (XL)
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17
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Differential in vivo gene expression of major Leptospira proteins in resistant or susceptible animal models. Appl Environ Microbiol 2012; 78:6372-6. [PMID: 22729538 DOI: 10.1128/aem.00911-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Transcripts of Leptospira 16S rRNA, FlaB, LigB, LipL21, LipL32, LipL36, LipL41, and OmpL37 were quantified in the blood of susceptible (hamsters) and resistant (mice) animal models of leptospirosis. We first validated adequate reference genes and then evaluated expression patterns in vivo compared to in vitro cultures. LipL32 expression was downregulated in vivo and differentially regulated in resistant and susceptible animals. FlaB expression was also repressed in mice but not in hamsters. In contrast, LigB and OmpL37 were upregulated in vivo. Thus, we demonstrated that a virulent strain of Leptospira differentially adapts its gene expression in the blood of infected animals.
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18
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Addy HS, Askora A, Kawasaki T, Fujie M, Yamada T. The filamentous phage ϕRSS1 enhances virulence of phytopathogenic Ralstonia solanacearum on tomato. PHYTOPATHOLOGY 2012; 102:244-51. [PMID: 22085298 DOI: 10.1094/phyto-10-11-0277] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Ralstonia solanacearum is the causative agent of bacterial wilt in many important crops. ϕRSS1 is a filamentous phage that infects R. solanacearum strains. Upon infection, it alters the physiological state and the behavior of host cells. Here, we show that R. solanacearum infected by ϕRSS1 becomes more virulent on host plants. Some virulence and pathogenicity factors, such as extracellular polysaccharide (EPS) synthesis and twitching motility, increased in the bacterial host cells infected with ϕRSS1, resulting in early wilting. Tomato plants inoculated with ϕRSS1-infected bacteria wilted 2 to 3 days earlier than those inoculated with wild-type bacteria. Infection with ϕRSS1 induced early expression of phcA, the global virulence regulator. phcA expression was detected in ϕRSS1-infected cells at cell density as low as 10(4) CFU/ml. Filamentous phages are assembled on the host cell surface and many phage particles accumulate on the cell surface. These surface-associated phage particles (phage proteins) may change the cell surface nature (hydrophobicity) to give high local cell densities. ϕRSS1 infection also enhanced PilA and type IV pilin production, resulting in increased twitching motility.
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Affiliation(s)
- Hardian S Addy
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530, Japan
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Hassanin AAI, Kaminishi Y, Funahashi A, Itakura T. Cytochrome P450 1C1 complementary DNA cloning, sequence analysis and constitutive expression induced by benzo-a-pyrene in Nile tilapia (Oreochromis niloticus). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2012; 109:17-24. [PMID: 22204985 DOI: 10.1016/j.aquatox.2011.11.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 11/19/2011] [Accepted: 11/22/2011] [Indexed: 05/31/2023]
Abstract
CYP1C is the newest member of the CYP1 family of P450s; however, its physiological significance, inducers, and metabolic functions are unknown. In this study, a new complementary DNA of the CYP1C subfamily encoding CYP1C1 was isolated from Nile tilapia (Oreochromis niloticus) liver after intracoelomic injection with benzo-a-pyrene (BaP). The full-length cDNA was 2223 base pair (bp) long and contained an open reading frame of 1581 bp encoding a protein of 526 amino acids and a stop codon. The sequence exhibited 3' non-coding region of 642 bp. The deduced amino acid sequence of O. niloticus CYP1C1 shows similarities of 86, 82.5, 79.7, 78.7, 77.8, 75.5, 69.6 and 61.3% with scup CYP1C1, killifish CYP1C1,1C2, Japanese eel CYP1C1, zebra fish CYP1C1, common carp CYP1C1, scup CYP1C2, common carp CYP1C2 and zebra fish CYP1C2, respectively. Phylogenetic tree based on the amino acids sequences clearly shows tilapia CYP1C1 and scup CYP1C1 to be more closely related to each other than to CYP1C genes from other species. Furthermore, for measuring BaP induction of CYP1C1 mRNA in different organs of tilapia (O. niloticus), β-actin gene as internal control was selected based on previous studies to assess their expression variability. Real time RCR results revealed that there was a large increase in CYP1C1 mRNA in liver (43.1), intestine (5.1) and muscle (2.4).
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Affiliation(s)
- Abeer A I Hassanin
- Laboratory of Marine Biotechnology, Faculty of Fisheries, Kagoshima University, 4-50-20 Shimoarata, Kagoshima 890-0056, Japan.
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20
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Zhang L, Zhang C, Ojcius DM, Sun D, Zhao J, Lin X, Li L, Li L, Yan J. The mammalian cell entry (Mce) protein of pathogenic Leptospira species is responsible for RGD motif-dependent infection of cells and animals. Mol Microbiol 2012; 83:1006-23. [DOI: 10.1111/j.1365-2958.2012.07985.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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21
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Luo Y, Liu Y, Sun D, Ojcius DM, Zhao J, Lin X, Wu D, Zhang R, Chen M, Li L, Yan J. InvA protein is a Nudix hydrolase required for infection by pathogenic Leptospira in cell lines and animals. J Biol Chem 2011; 286:36852-63. [PMID: 21862592 PMCID: PMC3196074 DOI: 10.1074/jbc.m111.219931] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Revised: 08/01/2011] [Indexed: 12/11/2022] Open
Abstract
Leptospirosis caused by pathogenic species of the genus Leptospira is a re-emerging zoonotic disease, which affects a wide variety of host species and is transmitted by contaminated water. The genomes of several pathogenic Leptospira species contain a gene named invA, which contains a Nudix domain. However, the function of this gene has never been characterized. Here, we demonstrated that the invA gene was highly conserved in protein sequence and present in all tested pathogenic Leptospira species. The recombinant InvA protein of pathogenic L. interrogans strain Lai hydrolyzed several specific dinucleoside oligophosphate substrates, reflecting the enzymatic activity of Nudix in Leptospira species. Pathogenic leptospires did not express this protein in media but temporarily expressed it at early stages (within 60 min) of infection of macrophages and nephric epithelial cells. Comparing with the wild type, the invA-deficient mutant displayed much lower infectivity and a significantly reduced survival rate in macrophages and nephric epithelial cells. Moreover, the invA-deficient leptospires presented an attenuated virulence in hamsters, caused mild histopathological damage, and were transmitted in lower numbers in the urine, compared with the wild-type strain. The invA revertant, made by complementing the invA-deficient mutant with the invA gene, reacquired virulence similar to the wild type in vitro and in vivo. The LD(50) in hamsters was 1000-fold higher for the invA-deficient mutant than for the invA revertant and wild type. These results demonstrate that the InvA protein is a Nudix hydrolase, and the invA gene is essential for virulence in pathogenic Leptospira species.
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Affiliation(s)
- Yihui Luo
- From the Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Medical College, Hangzhou, Zhejiang 310003, China
- the Department of Medical Microbiology and Parasitology, College of Medicine, and
| | - Yan Liu
- the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Dexter Sun
- the New York Presbyterian Hospital and Hospital for Special Surgery, Weill Medical College, Cornell University SinoUnited Health, New York, New York 10021, and
| | - David M. Ojcius
- the Health Sciences Research Institute and School of Natural Sciences, University of California, Merced, California 95343
| | - Jinfang Zhao
- From the Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Medical College, Hangzhou, Zhejiang 310003, China
- the Department of Medical Microbiology and Parasitology, College of Medicine, and
| | - Xuai Lin
- From the Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Medical College, Hangzhou, Zhejiang 310003, China
- the Department of Medical Microbiology and Parasitology, College of Medicine, and
| | - Dong Wu
- the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Rongguang Zhang
- the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Ming Chen
- the Department of Bioinformatics, College of Life Science, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Lanjuan Li
- From the Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Medical College, Hangzhou, Zhejiang 310003, China
| | - Jie Yan
- From the Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Medical College, Hangzhou, Zhejiang 310003, China
- the Department of Medical Microbiology and Parasitology, College of Medicine, and
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Reverse-transcriptase quantitative PCR method to detect uptake of hydrogen produced from cyanobacteria by Alcaligenes hydrogenophilus, an aerobic hydrogen-oxidising bacterium. Arch Microbiol 2011; 193:687-92. [DOI: 10.1007/s00203-011-0714-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Revised: 02/06/2011] [Accepted: 04/29/2011] [Indexed: 11/25/2022]
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23
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Evaluation of candidate reference genes in Clostridium difficile for gene expression normalization. Anaerobe 2010; 16:439-43. [DOI: 10.1016/j.anaerobe.2010.06.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 06/16/2010] [Accepted: 06/20/2010] [Indexed: 02/04/2023]
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24
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MONARD C, MARTIN-LAURENT F, DEVERS-LAMRANI M, LIMA O, VANDENKOORNHUYSE P, BINET F. atzgene expressions during atrazine degradation in the soil drilosphere. Mol Ecol 2010; 19:749-59. [DOI: 10.1111/j.1365-294x.2009.04503.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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