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Juthani R, Das A, Doss K, Mandal J. Exploring the use of Congo red agar in improving the serotyping of non-serotypeable Shigella with In-silico evidence. Indian J Med Microbiol 2023; 44:100381. [PMID: 37356833 DOI: 10.1016/j.ijmmb.2023.100381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/27/2022] [Accepted: 04/26/2023] [Indexed: 06/27/2023]
Abstract
OBJECTIVES To assess if congo red could make non-serotypeable Shigella strains serotypeable and to employ molecular docking to determine the basis of the same phenomenon. METHODS We used 42 bacterial strains of non-serotypeable Shigella collected from 2012 to 2019 for this study. Each bacterial strain was freshly inoculated onto congo red agar and incubated at 37° C for 18-24 h. Bacterial colonies obtained were re-subjected to biochemical tests followed by serotyping and serogrouping. In-silico studies to investigate the interaction between MxiC protein of T3SS and O-antigen LPS with congo red were performed. RESULTS Of the total 42 non-serotypeable Shigella studied, (26/42)62% were capable of being serotyped following the use of congo red agar, 65% were Shigella flexneri, 19% were Shigella dysenteriae, while 2 strains (7%) each of Shigella boydii and Shigella sonnei were detected. We observed no change in their biochemical properties. The in-silico molecular docking studies revealed high binding affinity between congo red and the B-Chain of Mxi C. Out of the 5 chains of the O-Antigen, congo red showed robust binding with the B-chain with the involvement of a cluster of hydrophobic interactions between them. This may have a crucial role in the conversion of non-serotypeable strains to serotypeable strains on exposure to congo red as observed in our study. CONCLUSION Congo red agar as a medium converts a sizeable percentage of non-serotypeable Shigella strains to serotypeable Shigella strains.
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Affiliation(s)
- Ronit Juthani
- Jawaharlal Institute of Postgraduate Medical Institute and Research (JIPMER), Puducherry, India.
| | - Ankita Das
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India.
| | - Kamali Doss
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India.
| | - Jharna Mandal
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Institute and Research (JIPMER), Puducherry, India.
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BipD of Burkholderia pseudomallei: Structure, Functions, and Detection Methods. Microorganisms 2021; 9:microorganisms9040711. [PMID: 33808203 PMCID: PMC8067316 DOI: 10.3390/microorganisms9040711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 01/13/2023] Open
Abstract
Melioidosis is a severe disease caused by Burkholderia pseudomallei (B. pseudomallei), a Gram-negative environmental bacterium. It is endemic in Southeast Asia and Northern Australia, but it is underreported in many other countries. The principal routes of entry for B. pseudomallei are skin penetration, inhalation, and ingestion. It mainly affects immunocompromised populations, especially patients with type 2 diabetes mellitus. The laboratory diagnosis of melioidosis is challenging due to its non-specific clinical manifestations, which mimic other severe infections. The culture method is considered an imperfect gold standard for the diagnosis of melioidosis due to its low sensitivity. Antibody detection has low sensitivity and specificity due to the high seropositivity among healthy people in endemic regions. Antigen detection using various proteins has been tested for the rapid determination of B. pseudomallei; however, it presents certain limitations in terms of its sensitivity and specificity. Therefore, this review aims to frame the present knowledge of a potential target known as the Burkholderia invasion protein D (BipD), including future directions for its detection using an aptamer-based sensor (aptasensor).
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Bajunaid W, Haidar-Ahmad N, Kottarampatel AH, Ourida Manigat F, Silué N, F. Tchagang C, Tomaro K, Campbell-Valois FX. The T3SS of Shigella: Expression, Structure, Function, and Role in Vacuole Escape. Microorganisms 2020; 8:microorganisms8121933. [PMID: 33291504 PMCID: PMC7762205 DOI: 10.3390/microorganisms8121933] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/01/2020] [Accepted: 12/03/2020] [Indexed: 12/18/2022] Open
Abstract
Shigella spp. are one of the leading causes of infectious diarrheal diseases. They are Escherichia coli pathovars that are characterized by the harboring of a large plasmid that encodes most virulence genes, including a type III secretion system (T3SS). The archetypal element of the T3SS is the injectisome, a syringe-like nanomachine composed of approximately 20 proteins, spanning both bacterial membranes and the cell wall, and topped with a needle. Upon contact of the tip of the needle with the plasma membrane, the injectisome secretes its protein substrates into host cells. Some of these substrates act as translocators or effectors whose functions are key to the invasion of the cytosol and the cell-to-cell spread characterizing the lifestyle of Shigella spp. Here, we review the structure, assembly, function, and methods to measure the activity of the injectisome with a focus on Shigella, but complemented with data from other T3SS if required. We also present the regulatory cascade that controls the expression of T3SS genes in Shigella. Finally, we describe the function of translocators and effectors during cell-to-cell spread, particularly during escape from the vacuole, a key element of Shigella’s pathogenesis that has yet to reveal all of its secrets.
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Affiliation(s)
- Waad Bajunaid
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Nathaline Haidar-Ahmad
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Anwer Hasil Kottarampatel
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - France Ourida Manigat
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Navoun Silué
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Caetanie F. Tchagang
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Kyle Tomaro
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - François-Xavier Campbell-Valois
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
- Correspondence:
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Ngo TD, Perdu C, Jneid B, Ragno M, Novion Ducassou J, Kraut A, Couté Y, Stopford C, Attrée I, Rietsch A, Faudry E. The PopN Gate-keeper Complex Acts on the ATPase PscN to Regulate the T3SS Secretion Switch from Early to Middle Substrates in Pseudomonas aeruginosa. J Mol Biol 2020; 432:166690. [PMID: 33289667 DOI: 10.1016/j.jmb.2020.10.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/09/2020] [Accepted: 10/19/2020] [Indexed: 10/23/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic bacterium of which the main virulence factor is the Type III Secretion System. The ATPase of this machinery, PscN (SctN), is thought to be localized at the base of the secretion apparatus and to participate in the recognition, chaperone dissociation and unfolding of exported T3SS proteins. In this work, a protein-protein interaction ELISA revealed the interaction of PscN with a wide range of exported T3SS proteins including the needle, translocator, gate-keeper and effector. These interactions were further confirmed by Microscale Thermophoresis that also indicated a preferential interaction of PscN with secreted proteins or protein-chaperone complex rather than with chaperones alone, in line with the release of the chaperones in the bacterial cytoplasm after the dissociation from their exported proteins. Moreover, we suggest a new role of the gate-keeper complex and the ATPase in the regulation of early substrates recognition by the T3SS. This finding sheds a new light on the mechanism of secretion switching from early to middle substrates in P. aeruginosa.
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Affiliation(s)
- Tuan-Dung Ngo
- Univ. Grenoble Alpes, CEA, INSERM, CNRS, Bacterial Pathogenesis and Cellular Responses, Interdisciplinary Research Institute of Grenoble, France
| | - Caroline Perdu
- Univ. Grenoble Alpes, CEA, INSERM, CNRS, Bacterial Pathogenesis and Cellular Responses, Interdisciplinary Research Institute of Grenoble, France
| | - Bakhos Jneid
- Univ. Grenoble Alpes, CEA, INSERM, CNRS, Bacterial Pathogenesis and Cellular Responses, Interdisciplinary Research Institute of Grenoble, France
| | - Michel Ragno
- Univ. Grenoble Alpes, CEA, INSERM, CNRS, Bacterial Pathogenesis and Cellular Responses, Interdisciplinary Research Institute of Grenoble, France
| | | | - Alexandra Kraut
- Univ. Grenoble Alpes, CEA, INSERM, IRIG, BGE, 38000 Grenoble, France
| | - Yohann Couté
- Univ. Grenoble Alpes, CEA, INSERM, IRIG, BGE, 38000 Grenoble, France
| | - Charles Stopford
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ina Attrée
- Univ. Grenoble Alpes, CEA, INSERM, CNRS, Bacterial Pathogenesis and Cellular Responses, Interdisciplinary Research Institute of Grenoble, France
| | - Arne Rietsch
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Eric Faudry
- Univ. Grenoble Alpes, CEA, INSERM, CNRS, Bacterial Pathogenesis and Cellular Responses, Interdisciplinary Research Institute of Grenoble, France.
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Wu P, Zhou S, Su Z, Liu C, Zeng F, Pang H, Xie M, Jian J. Functional characterization of T3SS C-ring component VscQ and evaluation of its mutant as a live attenuated vaccine in zebrafish (Danio rerio) model. FISH & SHELLFISH IMMUNOLOGY 2020; 104:123-132. [PMID: 32473362 DOI: 10.1016/j.fsi.2020.05.063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 05/02/2020] [Accepted: 05/23/2020] [Indexed: 06/11/2023]
Abstract
Vibrio alginolyticus, a Gram-negative bacterium, has been recognized as an opportunistic pathogen in marine animals as well as humans. Type III secretion system (T3SS) is critical for pathogen virulence and disease development. However, no more information is known about the C-ring component VscQ and its physiological role. In this study, gene vscQ was cloned from V. alginolyticus wild-type strain HY9901 and the mutant strain HY9901ΔvscQ was constructed by the in-frame deletion method. The HY9901ΔvscQ mutant showed an attenuated swarming phenotype and a closely 4.6-fold decrease in the virulence to Danio rerio. However, the HY9901ΔvscQ mutant showed no difference in growth, biofilm formation and ECPase activity. HY9901ΔvscQ reduces the release of LDH, NO and caspase-3 activity of infected FHM cell, which are involved in fish cell apoptosis. Deletion of gene vscQ downregulates the expression level of T3SS-related genes including vscL, vopB, hop, vscO, vscK, vopD, vcrV and vopS and flagellum-related genes (flaA and fliG). And Danio rerio vaccinated via i.m injection with HY9901ΔvscQ induced a relative percent survival (RPS) value of 71% after challenging with the wild-type HY9901. Real-time PCR assays showed that vaccination with HY9901ΔvscQ enhanced the expression of immune-related genes, including TNF-α, TLR5, IL-6R, IgM and c/ebpβ in liver and spleen after vaccination, indicating that it is able to induce humoral and cell-mediated immune response in zebrafish. These results demonstrate that the HY9901ΔvscQ mutant could be used as an effective live vaccine to combat V. alginolyticus infection.
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Affiliation(s)
- Peiwen Wu
- Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, 524025, China; Fisheries College of Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang 524025, China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, 524025, China
| | - Shihui Zhou
- Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, 524025, China; Fisheries College of Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang 524025, China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, 524025, China
| | - Zehui Su
- Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, 524025, China; Fisheries College of Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang 524025, China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, 524025, China
| | - Chang Liu
- Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, 524025, China; Fisheries College of Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang 524025, China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, 524025, China
| | - Fuyuan Zeng
- Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, 524025, China; Fisheries College of Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang 524025, China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, 524025, China
| | - Huanying Pang
- Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, 524025, China; Fisheries College of Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang 524025, China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, 524025, China; Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China.
| | - Miao Xie
- Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, 524025, China; Fisheries College of Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang 524025, China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, 524025, China
| | - Jichang Jian
- Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, 524025, China; Fisheries College of Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang 524025, China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, 524025, China; Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China.
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Zhou S, Tu X, Pang H, Hoare R, Monaghan SJ, Luo J, Jian J. A T3SS Regulator Mutant of Vibrio alginolyticus Affects Antibiotic Susceptibilities and Provides Significant Protection to Danio rerio as a Live Attenuated Vaccine. Front Cell Infect Microbiol 2020; 10:183. [PMID: 32411620 PMCID: PMC7198820 DOI: 10.3389/fcimb.2020.00183] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 04/06/2020] [Indexed: 11/13/2022] Open
Abstract
Vibrio alginolyticus is a major cause of Vibriosis in farmed marine aquatic animals and has caused large economic losses to the Asian aquaculture industry in recent years. Therefore, it is necessary to control V. alginolyticus effectively. The virulence mechanism of V. alginolyticus, the Type III secretion system (T3SS), is closely related to its pathogenicity. In this study, the T3SS gene tyeA was cloned from V. alginolyticus wild-type strain HY9901 and the results showed that the deduced amino acid sequence of V. alginolyticus tyeA shared 75–83% homology with other Vibrio spp. The mutant strain HY9901ΔtyeA was constructed by Overlap-PCR and homologous recombination techniques. The HY9901ΔtyeA mutant exhibited an attenuated swarming phenotype and an ~40-fold reduction in virulence to zebrafish. However, the HY9901ΔtyeA mutant showed no difference in growth, biofilm formation and ECPase activity. Antibiotic susceptibility test was observed that wild and mutant strains were extremely susceptible to Amikacin, Minocycline, Gentamicin, Cefperazone; and resistant to oxacillin, clindamycin, ceftazidime. In contrast wild strains are sensitive to tetracycline, chloramphenicol, kanamycin, doxycycline, while mutant strains are resistant to them. qRT-PCR was employed to analyze the transcription levels of T3SS-related genes, the results showed that compared with HY9901 wild type, ΔtyeA had increased expression of vscL, vscK, vscO, vopS, vopN, vscN, and hop. Following vaccination with the mutant strain, zebrafish had significantly higher survival than controls following infection with the wild-type HY9901 (71.2% relative percent survival; RPS). Analysis of immune gene expression by qPCR showed that vaccination with HY9901ΔtyeA increased the expression of IgM, IL-1β, IL-6, and TNF-α in zebrafish. This study provides evidence of protective efficacy of a live attenuated vaccine targeting the T3SS of V. alginolyticus which may be facilitated by up-regulated pro-inflammatory and immunoglobulin-related genes.
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Affiliation(s)
- Shihui Zhou
- Shenzhen Institute of Guangdong Ocean University, Shenzhen, China.,Fisheries College, Guangdong Ocean University, Zhanjiang, China.,Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, China.,Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, China.,Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xueting Tu
- Shenzhen Institute of Guangdong Ocean University, Shenzhen, China.,Fisheries College, Guangdong Ocean University, Zhanjiang, China.,Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, China.,Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, China.,Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Huanying Pang
- Shenzhen Institute of Guangdong Ocean University, Shenzhen, China.,Fisheries College, Guangdong Ocean University, Zhanjiang, China.,Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, China.,Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, China.,Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Rowena Hoare
- Institute of Aquaculture, University of Stirling, Stirling, United Kingdom
| | - Sean J Monaghan
- Institute of Aquaculture, University of Stirling, Stirling, United Kingdom
| | - Jiajun Luo
- Fisheries College, Guangdong Ocean University, Zhanjiang, China.,Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, China.,Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, China
| | - Jichan Jian
- Fisheries College, Guangdong Ocean University, Zhanjiang, China.,Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, China.,Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, China.,Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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7
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Cervantes-Rivera R, Tronnet S, Puhar A. Complete genome sequence and annotation of the laboratory reference strain Shigella flexneri serotype 5a M90T and genome-wide transcriptional start site determination. BMC Genomics 2020; 21:285. [PMID: 32252626 PMCID: PMC7132871 DOI: 10.1186/s12864-020-6565-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 02/07/2020] [Indexed: 01/19/2023] Open
Abstract
Background Shigella is a Gram-negative facultative intracellular bacterium that causes bacillary dysentery in humans. Shigella invades cells of the colonic mucosa owing to its virulence plasmid-encoded Type 3 Secretion System (T3SS), and multiplies in the target cell cytosol. Although the laboratory reference strain S. flexneri serotype 5a M90T has been extensively used to understand the molecular mechanisms of pathogenesis, its complete genome sequence is not available, thereby greatly limiting studies employing high-throughput sequencing and systems biology approaches. Results We have sequenced, assembled, annotated and manually curated the full genome of S. flexneri 5a M90T. This yielded two complete circular contigs, the chromosome and the virulence plasmid (pWR100). To obtain the genome sequence, we have employed long-read PacBio DNA sequencing followed by polishing with Illumina RNA-seq data. This provides a new hybrid strategy to prepare gapless, highly accurate genome sequences, which also cover AT-rich tracks or repetitive sequences that are transcribed. Furthermore, we have performed genome-wide analysis of transcriptional start sites (TSS) and determined the length of 5′ untranslated regions (5′-UTRs) at typical culture conditions for the inoculum of in vitro infection experiments. We identified 6723 primary TSS (pTSS) and 7328 secondary TSS (sTSS). The S. flexneri 5a M90T annotated genome sequence and the transcriptional start sites are integrated into RegulonDB (http://regulondb.ccg.unam.mx) and RSAT (http://embnet.ccg.unam.mx/rsat/) databases to use their analysis tools in the S. flexneri 5a M90T genome. Conclusions We provide the first complete genome for S. flexneri serotype 5a, specifically the laboratory reference strain M90T. Our work opens the possibility of employing S. flexneri M90T in high-quality systems biology studies such as transcriptomic and differential expression analyses or in genome evolution studies. Moreover, the catalogue of TSS that we report here can be used in molecular pathogenesis studies as a resource to know which genes are transcribed before infection of host cells. The genome sequence, together with the analysis of transcriptional start sites, is also a valuable tool for precise genetic manipulation of S. flexneri 5a M90T. Further, we present a new hybrid strategy to prepare gapless, highly accurate genome sequences. Unlike currently used hybrid strategies combining long- and short-read DNA sequencing technologies to maximize accuracy, our workflow using long-read DNA sequencing and short-read RNA sequencing provides the added value of using non-redundant technologies, which yield distinct, exploitable datasets.
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Affiliation(s)
- Ramón Cervantes-Rivera
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), 901 87 Umeå, Sweden.,Umeå Centre for Microbial Research (UCMR), 901 87, Umeå, Sweden.,Department of Molecular Biology, Umeå University, 901 87, Umeå, Sweden
| | - Sophie Tronnet
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), 901 87 Umeå, Sweden.,Umeå Centre for Microbial Research (UCMR), 901 87, Umeå, Sweden.,Department of Molecular Biology, Umeå University, 901 87, Umeå, Sweden
| | - Andrea Puhar
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), 901 87 Umeå, Sweden. .,Umeå Centre for Microbial Research (UCMR), 901 87, Umeå, Sweden. .,Department of Molecular Biology, Umeå University, 901 87, Umeå, Sweden.
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8
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Mukhopadhyay S, Ganguli S, Chakrabarti S. <em>Shigella</em> pathogenesis: molecular and computational insights. AIMS MOLECULAR SCIENCE 2020. [DOI: 10.3934/molsci.2020007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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9
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Zhuang Q, Dai F, Zhao X, Shao Y, Guo M, Lv Z, Li C, Zhang W. Cloning and characterization of the virulence factor Hop from Vibrio splendidus. Microb Pathog 2019; 139:103900. [PMID: 31790795 DOI: 10.1016/j.micpath.2019.103900] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 11/11/2019] [Accepted: 11/28/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND Vibrio splendidus is an aquaculture pathogen that can cause skin ulcer syndrome (SUS) in Apostichopus japonicus. HopPmaJ is a type III system effector (T3SE) that has been reported to be an important virulence factor. In this study, a gene named hop, which encodes HopPmaJ in V. splendidus was cloned and its cytotoxicity to coelomocytes and its effects on the expression of immune-related genes in A. japonicus were characterized. METHODS Real time reverse transcription PCR (RT-PCR) was used to determine the expression of the hop gene under various conditions. To obtain the purified Hop, hop gene was conditionally expressed in Escherichia coli BL21(DE3) and was purified by GST tag. The cytotoxicity of Hop to coelomocyte was determined using MTT method, and the effect of Hop on the expression of immune-related genes was determined using real time RT-PCR. RESULTS The deduced amino acid sequence of Hop from V. splendidus shared 84%-96% homology with those of Hops from other Vibrio spp. The expression of hop gene was induced not only by host-pathogen contact but also by high cell density. Purified recombinant Hop (rHop) showed cytotoxicity to the coelomocyte of A. japonicus. The cell viability decreased to approximately 42%, 26%, 32%, 30% and 20%, when 30, 50, 60, 80 and 100 μL of purified rHop was added, respectively. After being injected with rHop, the expression levels of immune-related genes that encode complement component (C1q) and caspase were significantly increased, and the production of reactive oxygen species were also increased in A. japonicus. CONCLUSION Our results indicated that Hop not only contributed to the cytotoxicity to coelomocyte, but also caused immune response in A. japonicus.
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Affiliation(s)
- Qiuting Zhuang
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Fa Dai
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Xuelin Zhao
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Yina Shao
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Ming Guo
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Zhimeng Lv
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Chenghua Li
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, PR China
| | - Weiwei Zhang
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China.
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10
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Khandia R, Dadar M, Munjal A, Dhama K, Karthik K, Tiwari R, Yatoo MI, Iqbal HMN, Singh KP, Joshi SK, Chaicumpa W. A Comprehensive Review of Autophagy and Its Various Roles in Infectious, Non-Infectious, and Lifestyle Diseases: Current Knowledge and Prospects for Disease Prevention, Novel Drug Design, and Therapy. Cells 2019; 8:cells8070674. [PMID: 31277291 PMCID: PMC6678135 DOI: 10.3390/cells8070674] [Citation(s) in RCA: 145] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/04/2019] [Accepted: 06/04/2019] [Indexed: 02/05/2023] Open
Abstract
Autophagy (self-eating) is a conserved cellular degradation process that plays important roles in maintaining homeostasis and preventing nutritional, metabolic, and infection-mediated stresses. Autophagy dysfunction can have various pathological consequences, including tumor progression, pathogen hyper-virulence, and neurodegeneration. This review describes the mechanisms of autophagy and its associations with other cell death mechanisms, including apoptosis, necrosis, necroptosis, and autosis. Autophagy has both positive and negative roles in infection, cancer, neural development, metabolism, cardiovascular health, immunity, and iron homeostasis. Genetic defects in autophagy can have pathological consequences, such as static childhood encephalopathy with neurodegeneration in adulthood, Crohn's disease, hereditary spastic paraparesis, Danon disease, X-linked myopathy with excessive autophagy, and sporadic inclusion body myositis. Further studies on the process of autophagy in different microbial infections could help to design and develop novel therapeutic strategies against important pathogenic microbes. This review on the progress and prospects of autophagy research describes various activators and suppressors, which could be used to design novel intervention strategies against numerous diseases and develop therapeutic drugs to protect human and animal health.
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Affiliation(s)
- Rekha Khandia
- Department of Genetics, Barkatullah University, Bhopal 462 026, Madhya Pradesh, India
| | - Maryam Dadar
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj 31975/148, Iran
| | - Ashok Munjal
- Department of Genetics, Barkatullah University, Bhopal 462 026, Madhya Pradesh, India.
| | - Kuldeep Dhama
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly 243 122, Uttar Pradesh, India.
| | - Kumaragurubaran Karthik
- Central University Laboratory, Tamil Nadu Veterinary and Animal Sciences University, Madhavaram Milk Colony, Chennai, Tamil Nadu 600051, India
| | - Ruchi Tiwari
- Department of Veterinary Microbiology and Immunology, College of Veterinary Sciences, UP Pandit Deen Dayal Upadhayay Pashu Chikitsa Vigyan Vishwavidyalay Evum Go-Anusandhan Sansthan (DUVASU), Mathura, Uttar Pradesh 281 001, India
| | - Mohd Iqbal Yatoo
- Sher-E-Kashmir University of Agricultural Sciences and Technology of Kashmir, Shalimar, Srinagar 190025, Jammu and Kashmir, India
| | - Hafiz M N Iqbal
- Tecnologico de Monterrey, School of Engineering and Sciences, Campus Monterrey, Ave. Eugenio Garza Sada 2501, Monterrey, N. L., CP 64849, Mexico
| | - Karam Pal Singh
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly 243 122, Uttar Pradesh, India
| | - Sunil K Joshi
- Department of Pediatrics, Division of Hematology, Oncology and Bone Marrow Transplantation, University of Miami School of Medicine, Miami, FL 33136, USA.
| | - Wanpen Chaicumpa
- Center of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
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11
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The Structure of an Injectisome Export Gate Demonstrates Conservation of Architecture in the Core Export Gate between Flagellar and Virulence Type III Secretion Systems. mBio 2019; 10:mBio.00818-19. [PMID: 31239376 PMCID: PMC6593402 DOI: 10.1128/mbio.00818-19] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Export of proteins through type III secretion systems (T3SS) is critical for motility and virulence of many major bacterial pathogens. Proteins are exported through a genetically defined export gate complex consisting of three proteins. We have recently shown at 4.2 Å that the flagellar complex of these three putative membrane proteins (FliPQR in flagellar systems, SctRST in virulence systems) assembles into an extramembrane helical assembly that likely seeds correct assembly of the rod. Here we present the structure of an equivalent complex from the Shigella virulence system at 3.5 Å by cryo-electron microscopy. This higher-resolution structure yields a more precise description of the structure and confirms the prediction of structural conservation in this core complex. Analysis of particle heterogeneity also suggests how the SctS/FliQ subunits sequentially assemble in the complex.IMPORTANCE Although predicted on the basis of sequence conservation, the work presented here formally demonstrates that all classes of type III secretion systems, flagellar or virulence, share the same architecture at the level of the core structures. This absolute conservation of the unusual extramembrane structure of the core export gate complex now allows work to move to focusing on both mechanistic studies of type III but also on fundamental studies of how such a complex is assembled.
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12
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Abstract
ABSTRACT
Shigella
is a genus of Gram-negative enteropathogens that have long been, and continue to be, an important public health concern worldwide. Over the past several decades,
Shigella
spp. have also served as model pathogens in the study of bacterial pathogenesis, and
Shigella flexneri
has become one of the best-studied pathogens on a molecular, cellular, and tissue level. In the arms race between
Shigella
and the host immune system,
Shigella
has developed highly sophisticated mechanisms to subvert host cell processes in order to promote infection, escape immune detection, and prevent bacterial clearance. Here, we give an overview of
Shigella
pathogenesis while highlighting innovative techniques and methods whose application has significantly advanced our understanding of
Shigella
pathogenesis in recent years.
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13
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Vibrio parahaemolyticus Senses Intracellular K + To Translocate Type III Secretion System 2 Effectors Effectively. mBio 2018; 9:mBio.01366-18. [PMID: 30042203 PMCID: PMC6058294 DOI: 10.1128/mbio.01366-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Many Gram-negative bacterial symbionts and pathogens employ a type III secretion system (T3SS) to live in contact with eukaryotic cells. Because T3SSs inject bacterial proteins (effectors) directly into host cells, the switching of secretory substrates between translocators and effectors in response to host cell attachment is a crucial step for the effective delivery of effectors. Here, we show that the protein secretion switch of Vibrio parahaemolyticus T3SS2, which is a main contributor to the enteropathogenicity of a food poisoning bacterium, is regulated by two gatekeeper proteins, VgpA and VgpB. In the absence of these gatekeepers, effector secretion was activated, but translocator secretion was abolished, causing the loss of virulence. We found that the K+ concentration, which is high inside the host cell but low outside, is a key factor for VgpA- and VgpB-mediated secretion switching. Exposure of wild-type bacteria to K+ ions provoked both gatekeeper and effector secretions but reduced the level of secretion of translocators. The secretion protein profile of wild-type bacteria cultured with 0.1 M KCl was similar to that of gatekeeper mutants. Furthermore, depletion of K+ ions in host cells diminished the efficiency of T3SS2 effector translocation. Thus, T3SS2 senses the high intracellular concentration of K+ of the host cell so that T3SS2 effectors can be effectively injected. The pathogenesis of many Gram-negative bacterial pathogens arises from a type III secretion system (T3SS), whereby bacterial proteins (effectors) are directly injected into host cells. The injected effectors then modify host cell functions. For effective delivery of effector proteins, bacteria need to both recognize host cell attachment and switch the type of secreted proteins. Here, we identified gatekeeper proteins that play important roles in a T3SS2 secretion switch of Vibrio parahaemolyticus, a causative agent of food-borne gastroenteritis. We also found that K+, which is present in high concentrations inside the host cell but in low concentrations outside, is a key factor for the secretion switch. Thus, V. parahaemolyticus senses the high intracellular K+ concentration, triggering the effective injection of effectors.
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14
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Pang H, Qiu M, Zhao J, Hoare R, Monaghan SJ, Song D, Chang Y, Jian J. Construction of a Vibrio alginolyticus hopPmaJ (hop) mutant and evaluation of its potential as a live attenuated vaccine in orange-spotted grouper (Epinephelus coioides). FISH & SHELLFISH IMMUNOLOGY 2018; 76:93-100. [PMID: 29427720 DOI: 10.1016/j.fsi.2018.02.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 01/31/2018] [Accepted: 02/06/2018] [Indexed: 06/08/2023]
Abstract
Vibrio alginolyticus, a bacterial pathogen in fish and humans, expresses a type III secretion system (T3SS) that is critical for pathogen virulence and disease development. However, little is known about the associated effectors (T3SEs) and their physiological role. In this study, the T3SE gene hopPmaJ (hop) was cloned from V. alginolyticus wild-type strain HY9901 and the mutant strain HY9901Δhop was constructed by the in-frame deletion method. The results showed that the deduced amino acid sequence of V. alginolyticus HopPmaJ shared 78-98% homology with other Vibrio spp. In addition, the HY9901Δhop mutant showed an attenuated swarming phenotype and a 2600-fold decrease in the virulence to grouper. However, the HY9901Δhop mutant showed no difference in morphology, growth, biofilm formation and ECPase activity. Finally, grouper vaccinated via intraperitoneal (IP) injection with HY9901Δhop induced a high antibody titer with a relative percent survival (RPS) value of 84% after challenging with the wild-type HY9901. Real-time PCR assays showed that vaccination with HY9901Δhop enhanced the expression of immune-related genes, including MHC-Iα, MHC-IIα, IgM, and IL-1β after vaccination, indicating that it is able to induce humoral and cell-mediated immune response in grouper. These results demonstrate that the HY9901Δhop mutant could be used as an effective live vaccine to combat V. alginolyticus in grouper.
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Affiliation(s)
- Huanying Pang
- College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, 524025, China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, 524025, China
| | - Mingsheng Qiu
- College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China
| | - Jingmin Zhao
- College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China
| | - Rowena Hoare
- Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| | - Sean J Monaghan
- Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| | - Dawei Song
- College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, 524025, China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, 524025, China
| | - Yunsheng Chang
- College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, 524025, China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, 524025, China
| | - Jichang Jian
- College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, 524025, China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, 524025, China.
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15
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Gaytán MO, Monjarás Feria J, Soto E, Espinosa N, Benítez JM, Georgellis D, González-Pedrajo B. Novel insights into the mechanism of SepL-mediated control of effector secretion in enteropathogenic Escherichia coli. Microbiologyopen 2017; 7:e00571. [PMID: 29277965 PMCID: PMC6011996 DOI: 10.1002/mbo3.571] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 10/30/2017] [Accepted: 11/03/2017] [Indexed: 11/13/2022] Open
Abstract
Type three secretion systems (T3SSs) are virulence determinants employed by several pathogenic bacteria as molecular syringes to inject effector proteins into host cells. Diarrhea‐producing enteropathogenic Escherichia coli (EPEC) uses a T3SS to colonize the intestinal tract. T3S is a highly coordinated process that ensures hierarchical delivery of three classes of substrates: early (inner rod and needle subunits), middle (translocators), and late (effectors). Translocation of effectors is triggered upon host‐cell contact in response to different environmental cues, such as calcium levels. The T3S substrate specificity switch from middle to late substrates in EPEC is regulated by the SepL and SepD proteins, which interact with each other and form a trimeric complex with the chaperone CesL. In this study, we investigated the link between calcium concentration and secretion regulation by the gatekeeper SepL. We found that calcium depletion promotes late substrate secretion in a translocon‐independent manner. Furthermore, the stability, formation, and subcellular localization of the SepL/SepD/CesL regulatory complex were not affected by the absence of calcium. In addition, we demonstrate that SepL interacts in a calcium‐independent manner with the major export gate component EscV, which in turn interacts with both middle and late secretion substrates, providing a docking site for T3S. These results suggest that EscV serves as a binding platform for both the SepL regulatory protein and secreted substrates during the ordered assembly of the T3SS.
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Affiliation(s)
- Meztlli O Gaytán
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Julia Monjarás Feria
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Eduardo Soto
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Norma Espinosa
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Julia M Benítez
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Dimitris Georgellis
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Bertha González-Pedrajo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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16
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El Hajjami N, Moussa S, Houssa J, Monteyne D, Perez-Morga D, Botteaux A. The inner-rod component of Shigella flexneri type 3 secretion system, MxiI, is involved in the transmission of the secretion activation signal by its interaction with MxiC. Microbiologyopen 2017; 7. [PMID: 29194994 PMCID: PMC5822323 DOI: 10.1002/mbo3.520] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 05/29/2017] [Accepted: 06/13/2017] [Indexed: 11/28/2022] Open
Abstract
The virulence of Shigella mainly resides in the use of a Type 3 Secretion System (T3SS) to inject several proteins inside the host cell. Three categories of proteins are hierarchically secreted: (1) the needle components (MxiH and MxiI), (2) the translocator proteins which form a pore (translocon) inside the host cell membrane, and (3) the effectors interfering with the host cell signaling pathways. In the absence of host cell contact, the T3SS is maintained in an “off” state by the presence of a tip complex. We have previously identified a gatekeeper protein, MxiC, which sequesters effectors inside the bacteria probably by interacting with MxiI, the inner‐rod component. Upon cell contact and translocon insertion, a signal is most likely transmitted from the top of the needle to the base, passing through the needle and allowing effectors release. However, the molecular mechanism underlying the transmission of the activation signal through the needle is still poorly understood. In this work, we investigate the role of MxiI in the activation of the T3SS by performing a mutational study. Interestingly we have shown that mutations of a single residue in MxiI (T82) induce an mxiC‐like phenotype and prevent the interaction with MxiC. Moreover, we have shown that the L26A mutation significantly reduces T3 secretion. The L26A mutation impairs the interaction between MxiI and Spa40, a keystone component of the switch between needle assembly and translocators secretion. The L26A mutation also sequesters MxiC. All these results highlight the crucial role of MxiI in regulating the secretion and transmitting the activation signal of the T3SS.
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Affiliation(s)
- Nargisse El Hajjami
- Laboratoire de Bactériologie Moléculaire, Faculté de Médecine, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Simon Moussa
- Laboratoire de Bactériologie Moléculaire, Faculté de Médecine, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Jonathan Houssa
- Laboratoire de Bactériologie Moléculaire, Faculté de Médecine, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Daniel Monteyne
- Laboratoire de Parasitologie Moléculaire, Faculté des Sciences, Université Libre de Bruxelles, Charleroi, Belgium.,Center for Microscopy and Molecular Imaging-CMMI, Université Libre de Bruxelles, Gosselies, Belgium
| | - David Perez-Morga
- Laboratoire de Parasitologie Moléculaire, Faculté des Sciences, Université Libre de Bruxelles, Charleroi, Belgium
| | - Anne Botteaux
- Laboratoire de Bactériologie Moléculaire, Faculté de Médecine, Université Libre de Bruxelles, Bruxelles, Belgium
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17
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Portaliou AG, Tsolis KC, Loos MS, Balabanidou V, Rayo J, Tsirigotaki A, Crepin VF, Frankel G, Kalodimos CG, Karamanou S, Economou A. Hierarchical protein targeting and secretion is controlled by an affinity switch in the type III secretion system of enteropathogenic Escherichia coli. EMBO J 2017; 36:3517-3531. [PMID: 29109154 DOI: 10.15252/embj.201797515] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 09/05/2017] [Accepted: 10/11/2017] [Indexed: 11/09/2022] Open
Abstract
Type III secretion (T3S), a protein export pathway common to Gram-negative pathogens, comprises a trans-envelope syringe, the injectisome, with a cytoplasm-facing translocase channel. Exported substrates are chaperone-delivered to the translocase, EscV in enteropathogenic Escherichia coli, and cross it in strict hierarchical manner, for example, first "translocators", then "effectors". We dissected T3S substrate targeting and hierarchical switching by reconstituting them in vitro using inverted inner membrane vesicles. EscV recruits and conformationally activates the tightly membrane-associated pseudo-effector SepL and its chaperone SepD. This renders SepL a high-affinity receptor for translocator/chaperone pairs, recognizing specific chaperone signals. In a second, SepD-coupled step, translocators docked on SepL become secreted. During translocator secretion, SepL/SepD suppress effector/chaperone binding to EscV and prevent premature effector secretion. Disengagement of the SepL/SepD switch directs EscV to dedicated effector export. These findings advance molecular understanding of T3S and reveal a novel mechanism for hierarchical trafficking regulation in protein secretion channels.
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Affiliation(s)
- Athina G Portaliou
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Konstantinos C Tsolis
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Maria S Loos
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Vassileia Balabanidou
- Institute of Molecular Biology and Biotechnology, FORTH (Foundation of Research and Technology), University of Crete, Heraklion, Greece
| | - Josep Rayo
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Alexandra Tsirigotaki
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Valerie F Crepin
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Gad Frankel
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | | | - Spyridoula Karamanou
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Anastassios Economou
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
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18
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Vander Broek CW, Stevens JM. Type III Secretion in the Melioidosis Pathogen Burkholderia pseudomallei. Front Cell Infect Microbiol 2017; 7:255. [PMID: 28664152 PMCID: PMC5471309 DOI: 10.3389/fcimb.2017.00255] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/31/2017] [Indexed: 02/03/2023] Open
Abstract
Burkholderia pseudomallei is a Gram-negative intracellular pathogen and the causative agent of melioidosis, a severe disease of both humans and animals. Melioidosis is an emerging disease which is predicted to be vastly under-reported. Type III Secretion Systems (T3SSs) are critical virulence factors in Gram negative pathogens of plants and animals. The genome of B. pseudomallei encodes three T3SSs. T3SS-1 and -2, of which little is known, are homologous to Hrp2 secretion systems of the plant pathogens Ralstonia and Xanthomonas. T3SS-3 is better characterized and is homologous to the Inv/Mxi-Spa secretion systems of Salmonella spp. and Shigella flexneri, respectively. Upon entry into the host cell, B. pseudomallei requires T3SS-3 for efficient escape from the endosome. T3SS-3 is also required for full virulence in both hamster and murine models of infection. The regulatory cascade which controls T3SS-3 expression and the secretome of T3SS-3 have been described, as well as the effect of mutations of some of the structural proteins. Yet only a few effector proteins have been functionally characterized to date and very little work has been carried out to understand the hierarchy of assembly, secretion and temporal regulation of T3SS-3. This review aims to frame current knowledge of B. pseudomallei T3SSs in the context of other well characterized model T3SSs, particularly those of Salmonella and Shigella.
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Affiliation(s)
- Charles W Vander Broek
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of EdinburghMidlothian, United Kingdom
| | - Joanne M Stevens
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of EdinburghMidlothian, United Kingdom
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19
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Shen DK, Blocker AJ. MxiA, MxiC and IpaD Regulate Substrate Selection and Secretion Mode in the T3SS of Shigella flexneri. PLoS One 2016; 11:e0155141. [PMID: 27171191 PMCID: PMC4865121 DOI: 10.1371/journal.pone.0155141] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 04/25/2016] [Indexed: 11/19/2022] Open
Abstract
Type III secretion systems (T3SSs) are central virulence devices for many Gram-negative bacterial pathogens of humans, animals & plants. Upon physical contact with eukaryotic host cells, they translocate virulence-mediating proteins, known as effectors, into them during infection. T3SSs are gated from the outside by host-cell contact and from the inside via two cytoplasmic negative regulators, MxiC and IpaD in Shigella flexneri, which together control the effector secretion hierarchy. Their absence leads to premature and increased secretion of effectors. Here, we investigated where and how these regulators act. We demonstrate that the T3SS inner membrane export apparatus protein MxiA plays a role in substrate selection. Indeed, using a genetic screen, we identified two amino acids located on the surface of MxiA's cytoplasmic region (MxiAC) which, when mutated, upregulate late effector expression and, in the case of MxiAI674V, also secretion. The cytoplasmic region of MxiA, but not MxiAN373D and MxiAI674V, interacts directly with the C-terminus of MxiC in a two-hybrid assay. Efficient T3S requires a cytoplasmic ATPase and the proton motive force (PMF), which is composed of the ΔΨ and the ΔpH. MxiA family proteins and their regulators are implicated in utilization of the PMF for protein export. However, our MxiA point mutants show similar PMF utilisation to wild-type, requiring primarily the ΔΨ. On the other hand, lack of MxiC or IpaD, renders the faster T3S seen increasingly dependent on the ΔpH. Therefore, MxiA, MxiC and IpaD act together to regulate substrate selection and secretion mode in the T3SS of Shigella flexneri.
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Affiliation(s)
- Da-Kang Shen
- School of Cellular & Molecular Medicine, Faculty of Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Ariel J. Blocker
- Schools of Cellular & Molecular Medicine and Biochemistry, Faculty of Biomedical Sciences, University of Bristol, Bristol, United Kingdom
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