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Liu X, Wang X, Sun B, Sun L. The Involvement of Thiamine Uptake in the Virulence of Edwardsiella piscicida. Pathogens 2022; 11:pathogens11040464. [PMID: 35456139 PMCID: PMC9026889 DOI: 10.3390/pathogens11040464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/11/2022] [Accepted: 04/11/2022] [Indexed: 11/16/2022] Open
Abstract
Edwardsiella piscicida is a pathogenic bacterium, which can infect a number of fish species and cause a disease termed edwardsiellosis, threatening global fish farming with high prevalence and mortality. Thiamine (Vitamin B1), functioning in the form of thiamine pyrophosphate (TPP), is essential for almost all organisms. Bacteria acquire TPP by biosynthesis or by transportation of exogenous thiamine. TPP availability has been associated with bacterial pathogenicity, but the underlying mechanisms remain to be discovered. The role of thiamine in the pathogenicity of E. piscicida is unknown. In this study, we characterized a thiamine transporter (TT) operon in E. piscicida. The deletion of the TT operon resulted in an intracellular TPP lacking situation, which led to attenuated overall pathogenicity, impaired abilities associated with motility and host cell adhesion, as well as decreased expression of certain flagellar and adhesion genes. Moreover, TPP starvation led to intracellular c-di-GMP reduction, and introducing into the TPP-suppressed mutant strain an exogenous diguanylate cyclase for c-di-GMP synthesis restored the virulence loss. Taken together, this work reveals the involvement of thiamine uptake in the virulence regulation of E. piscicida, with c-di-GMP implicated in the process. These finding could be employed to explore potential drug targets against E. piscicida.
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Affiliation(s)
- Xin Liu
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, CAS Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; (X.L.); (X.W.)
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao 266003, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinhui Wang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, CAS Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; (X.L.); (X.W.)
| | - Boguang Sun
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, CAS Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; (X.L.); (X.W.)
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao 266003, China
- Correspondence: (B.S.); (L.S.)
| | - Li Sun
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, CAS Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; (X.L.); (X.W.)
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao 266003, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence: (B.S.); (L.S.)
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Li J, Tang L, Wang P, Li G, Jin H, Mo Z. Identification and application of T3SS translocation signal in Edwardsiella piscicida attenuated carrier as a bivalent vaccine. JOURNAL OF FISH DISEASES 2021; 44:513-520. [PMID: 33682163 DOI: 10.1111/jfd.13338] [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: 11/04/2020] [Revised: 01/03/2021] [Accepted: 01/05/2021] [Indexed: 06/12/2023]
Abstract
Type III secretion system (T3SS)-dependent translocation has been used to deliver heterologous antigens by vaccine carriers into host cells. In this research, we identified the translocation signal of Edwardsiella piscicida T3SS effector EseG and constructed an antibiotic resistance-free balanced-lethal system as attenuated vaccine carrier to present antigens by T3SS. Edwardsiella piscicida LSE40 asd gene deletion mutant was constructed and complemented with pYA3342 harbouring the asd (aspartate β-semialdehyde dehydrogenase) gene from Salmonella. Fusion proteins composed of EseG N-terminal 1-108 amino acids and the TEM1-β-lactamase reporter were inserted in plasmid pYA3342. The fusion protein could secrete into the cell culture, translocate into HeLa cells, and localize in the membrane fraction. Then, the double gene deletion mutant LSE40ΔasdΔpurA was constructed as an attenuated vaccine carrier, and Aeromonas hydrophila GapA (glyceraldehyde-3-phosphate dehydrogenase) was fused with the translocation signal, instead of the TEM1-β-lactamase reporter. The bivalent vaccine could protect blue gourami (Trichogaster trichopterus) against E. piscicida and A. hydrophila, with the relative per cent survival of 80.77% and 63.83%, respectively. These results indicated that EseG N-terminal 1-108 amino acid peptide was the translocation signal of E. piscicida T3SS, which could be used to construct bivalent vaccines based on an attenuated E. piscicida carrier.
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Affiliation(s)
- Jie Li
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Lei Tang
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Pengmei Wang
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Guiyang Li
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Huaiyuan Jin
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
- College of Aquaculture, Tianjin Agricultural University, Tianjin, China
| | - Zhaolan Mo
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
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Abstract
Edwardsiella piscicida is an Enterobacteriaceae that is abundant in water and causes food and waterborne infections in fish, animals, and humans. The bacterium causes Edwardsiellosis in farmed fish and can lead to severe economic losses in aquaculture worldwide. E. piscicida is an intracellular pathogen that can also cause systemic infection. Type III and type VI secretion systems are the bacterium’s most lethal weapons against host defenses. It also possesses multi-antibiotic resistant genes and is selected and enriched in the environment due to the overuse of antibiotics. Therefore, the bacterium has great potential to contribute to the evolution of the resistome. All these properties have made this bacterium a perfect model to study bacteria virulence mechanisms and the spread of antimicrobial genes in the environment. We summarize recent advance in E. piscicida biology and provide insights into future research in virulence mechanisms, vaccine development and novel therapeutics.
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Affiliation(s)
- Ka Yin Leung
- a Guangdong Technion - Israel Institute of Technology, Biotechnology and Food Engineering , Shantou , Guangdong , China
| | - Qiyao Wang
- b State Key Laboratory of Bioreactor Engineering, School of Biotechnology, East China University of Science and Technology , Shanghai , China.,c Shanghai Engineering Research Center of Marine Cultured Animal Vaccines, East China University of Science and Technology , Shanghai , China.,d Shanghai Collaborative Innovation Center for Biomanufacturing, East China University of Science and Technology , Shanghai , China
| | - Zhiyun Yang
- a Guangdong Technion - Israel Institute of Technology, Biotechnology and Food Engineering , Shantou , Guangdong , China
| | - Bupe A Siame
- e Department of Biology , Trinity Western University , Langley , BC , Canada
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The Edwardsiella piscicida Type III Translocon Protein EseC Inhibits Biofilm Formation by Sequestering EseE. Appl Environ Microbiol 2019; 85:AEM.02133-18. [PMID: 30770403 DOI: 10.1128/aem.02133-18] [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: 09/04/2018] [Accepted: 02/04/2019] [Indexed: 11/20/2022] Open
Abstract
The type III secretion system (T3SS) is one of the most important virulence factors of the fish pathogen Edwardsiella piscicida It contains three translocon proteins, EseB, EseC, and EseD, required for translocation of effector proteins into host cells. We have previously shown that EseB forms filamentous appendages on the surface of E. piscicida, and these filamentous structures mediate bacterial cell-cell interactions promoting autoaggregation and biofilm formation. In the present study, we show that EseC, but not EseD, inhibits the autoaggregation and biofilm formation of E. piscicida At 18 h postsubculture, a ΔeseC strain developed strong autoaggregation and mature biofilm formation, accompanied by enhanced formation of EseB filamentous appendages. This is in contrast to the weak autoaggregation and immature biofilm formation seen in the E. piscicida wild-type strain. EseE, a protein that directly binds to EseC and also positively regulates the transcription of the escC-eseE operon, was liberated and showed increased levels in the absence of EseC. This led to augmented transcription of the escC-eseE operon, thereby increasing the steady-state protein levels of intracellular EseB, EseD, and EseE, as well as biofilm formation. Notably, the levels of intracellular EseB and EseD produced by the ΔeseE and ΔeseC ΔeseE strains were similar but remarkably lower than those produced by the wild-type strain at 18 h postsubculture. Taken together, we have shown that the translocon protein EseC inhibits biofilm formation through sequestering EseE, a positive regulator of the escC-eseE operon.IMPORTANCE Edwardsiella piscicida, previously known as Edwardsiella tarda, is a Gram-negative intracellular pathogen that mainly infects fish. The type III secretion system (T3SS) plays a pivotal role in its pathogenesis. The T3SS translocon protein EseB is required for the assembly of filamentous appendages on the surface of E. piscicida The interactions between the appendages facilitate autoaggregation and biofilm formation. In this study, we explored the role of the other two translocon proteins, EseC and EseD, in biofilm formation. We have demonstrated that EseC, but not EseD, inhibits the autoaggregation and biofilm formation of E. piscicida, providing new insights into the regulatory mechanism involved in E. piscicida biofilm formation.
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Cao H, Yang C, Quan S, Hu T, Zhang L, Zhang Y, Yang D, Liu Q. Novel T3SS effector EseK in Edwardsiella piscicida is chaperoned by EscH and EscS to express virulence. Cell Microbiol 2017; 20. [PMID: 29024267 DOI: 10.1111/cmi.12790] [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: 04/18/2017] [Revised: 09/18/2017] [Accepted: 09/20/2017] [Indexed: 01/08/2023]
Abstract
Bacterium usually utilises type III secretion systems (T3SS) to deliver effectors directly into host cells with the aids of chaperones. Hence, it is very important to identify bacterial T3SS effectors and chaperones for better understanding of host-pathogen interactions. Edwardsiella piscicida is an invasive enteric bacterium, which infects a wide range of hosts from fish to human. Given E. piscicida encodes a functional T3SS to promote infection, very few T3SS effectors and chaperones have been identified in this bacterium so far. Here, we reported that EseK is a new T3SS effector protein translocated by E. piscicida. Bioinformatic analysis indicated that escH and escS encode two putative class I T3SS chaperones. Further investigation indicated that EscH and EscS can enhance the secretion and translocation of EseK. EscH directly binds EseK through undetermined binding domains, whereas EscS binds EseK via its N-terminal α-helix. We also found that EseK has an N-terminal chaperone-binding domain, which binds EscH and EscS to form a ternary complex. Zebrafish infection experiments showed that EseK and its chaperones EscH and EscS are necessary for bacterial colonisation in zebrafish. This work identified a new T3SS effector, EseK, and its two T3SS chaperones, EscH and EscS, in E. piscicida, which enriches our knowledge of bacterial T3SS effector-chaperone interaction and contributes to our understanding of bacterial pathogenesis.
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Affiliation(s)
- Huifang Cao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Cuiting Yang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Shu Quan
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Tianjian Hu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Lingzhi Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Yuanxing Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China.,Shanghai Collaborative Innovation Center for Bio-manufacturing Technology, Shanghai, China
| | - Dahai Yang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Qin Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China.,Shanghai Collaborative Innovation Center for Bio-manufacturing Technology, Shanghai, China
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Regulation of Type III Secretion of Translocon and Effector Proteins by the EsaB/EsaL/EsaM Complex in Edwardsiella tarda. Infect Immun 2017. [PMID: 28630070 DOI: 10.1128/iai.00322-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The type III secretion system (T3SS) plays a crucial role in the pathogenesis of many Gram-negative bacteria, including Edwardsiella tarda, an important fish pathogen. Within the E. tarda T3SS, there are three proteins (EsaB/EsaL/EsaM) that are homologous to proteins present in many other bacteria, including SpiC/SsaL/SsaM in Salmonella, SepD/SepL/CesL in enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC), and YscB/YopN/SycN in Yersinia EsaL was found to interact with both EsaB and EsaM within the bacterial cell, as revealed by a coimmunoprecipitation assay. Moreover, EsaM is required for EsaB stability, and the two proteins interact with each other. EsaB, EsaL, and EsaM are all indispensable for the secretion of the T3SS translocon protein EseC into supernatants under pH 5.5 and pH 7.2 conditions. Unlike EseC, EseG is a T3SS effector whose secretion is suppressed by EsaL at pH 7.2 while it is promoted at pH 5.5 condition. Despite this finding, mutant strains lacking EsaB, EsaL, or EsaM (i.e., the ΔesaB, ΔesaL, or ΔesaM strain, respectively) were all outcompeted by wild-type E. tarda during a coinfection model. These results demonstrate that EsaB/EsaL/EsaM form a ternary complex controlling the secretion of T3SS translocon and effector proteins and contributing to E. tarda pathogenesis.
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Hou M, Chen R, Yang D, Núñez G, Wang Z, Wang Q, Zhang Y, Liu Q. Identification and functional characterization of EseH, a new effector of the type III secretion system ofEdwardsiella piscicida. Cell Microbiol 2016; 19. [DOI: 10.1111/cmi.12638] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 05/30/2016] [Accepted: 06/17/2016] [Indexed: 12/26/2022]
Affiliation(s)
- Mingyu Hou
- State Key Laboratory of Bioreactor Engineering; East China University of Science and Technology; Shanghai 200237 China
| | - Ran Chen
- State Key Laboratory of Bioreactor Engineering; East China University of Science and Technology; Shanghai 200237 China
| | - Dahai Yang
- State Key Laboratory of Bioreactor Engineering; East China University of Science and Technology; Shanghai 200237 China
- Shanghai Engineering Research Center of Marine Cultured Animal Vaccines; Shanghai 200237 China
- Shanghai Collaborative Innovation Center for Biomanufacturing; Shanghai 200237 China
| | - Gabriel Núñez
- Department of Pathology and Comprehensive Cancer Center; University of Michigan; Ann Arbor MI 48109 USA
| | - Zhuang Wang
- State Key Laboratory of Bioreactor Engineering; East China University of Science and Technology; Shanghai 200237 China
| | - Qiyao Wang
- State Key Laboratory of Bioreactor Engineering; East China University of Science and Technology; Shanghai 200237 China
- Shanghai Engineering Research Center of Marine Cultured Animal Vaccines; Shanghai 200237 China
- Shanghai Collaborative Innovation Center for Biomanufacturing; Shanghai 200237 China
| | - Yuanxing Zhang
- State Key Laboratory of Bioreactor Engineering; East China University of Science and Technology; Shanghai 200237 China
- Shanghai Engineering Research Center of Marine Cultured Animal Vaccines; Shanghai 200237 China
- Shanghai Collaborative Innovation Center for Biomanufacturing; Shanghai 200237 China
| | - Qin Liu
- State Key Laboratory of Bioreactor Engineering; East China University of Science and Technology; Shanghai 200237 China
- Shanghai Engineering Research Center of Marine Cultured Animal Vaccines; Shanghai 200237 China
- Shanghai Collaborative Innovation Center for Biomanufacturing; Shanghai 200237 China
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EseE of Edwardsiella tarda Augments Secretion of Translocon Protein EseC and Expression of the escC-eseE Operon. Infect Immun 2016; 84:2336-2344. [PMID: 27271743 DOI: 10.1128/iai.00106-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 05/26/2016] [Indexed: 02/07/2023] Open
Abstract
Edwardsiella tarda is an important Gram-negative pathogen that employs a type III secretion system (T3SS) to deliver effectors into host cells to facilitate bacterial survival and replication. These effectors are translocated into host cells through a translocon complex composed of three secreted proteins, namely, EseB, EseC, and EseD. The secretion of EseB and EseD requires a chaperone protein called EscC, whereas the secretion of EseC requires the chaperone EscA. In this study, we identified a novel protein (EseE) that also regulates the secretion of EseC. An eseE deletion mutant secreted much less EseC into supernatants, accompanied by increased EseC levels within bacterial cells. We also demonstrated that EseE interacted directly with EseC in a pulldown assay. Interestingly, EseC, EseE, and EscA were able to form a ternary complex, as revealed by pulldown and gel filtration assays. Of particular importance, the deletion of eseE resulted in decreased levels of EseB and EseD proteins in both the bacterial pellet and supernatant fraction. Furthermore, real-time PCR assays showed that EseE positively regulated the transcription of the translocon operon escC-eseE, comprising escC, eseB, escA, eseC, eseD, and eseE These effects of EseE on the translocon components/operon appeared to have a functional consequence, since the ΔeseE strain was outcompeted by wild-type E. tarda in a mixed infection in blue gourami fish. Collectively, our results demonstrate that EseE not only functions as a chaperone for EseC but also acts as a positive regulator controlling the expression of the translocon operon escC-eseE, thus contributing to the pathogenesis of E. tarda in fish.
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Zhou Y, Liu LY, He TT, Laghari ZA, Nie P, Gao Q, Xie HX. Edwardsiella tarda EsaE (Orf19 protein) is required for the secretion of type III substrates, and pathogenesis in fish. Vet Microbiol 2016; 190:12-18. [DOI: 10.1016/j.vetmic.2016.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/14/2016] [Accepted: 05/09/2016] [Indexed: 10/21/2022]
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Expression, secretion and bactericidal activity of type VI secretion system in Vibrio anguillarum. Arch Microbiol 2016; 198:751-60. [DOI: 10.1007/s00203-016-1236-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/21/2016] [Accepted: 05/05/2016] [Indexed: 10/21/2022]
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Edwardsiella tarda EscE (Orf13 Protein) Is a Type III Secretion System-Secreted Protein That Is Required for the Injection of Effectors, Secretion of Translocators, and Pathogenesis in Fish. Infect Immun 2015; 84:2-10. [PMID: 26459509 DOI: 10.1128/iai.00986-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 10/03/2015] [Indexed: 11/20/2022] Open
Abstract
The type III secretion system (T3SS) of Edwardsiella tarda is crucial for its intracellular survival and pathogenesis in fish. The orf13 gene (escE) of E. tarda is located 84 nucleotides (nt) upstream of esrC in the T3SS gene cluster. We found that EscE is secreted and translocated in a T3SS-dependent manner and that amino acids 2 to 15 in the N terminus were required for a completely functional T3SS in E. tarda. Deletion of escE abolished the secretion of T3SS translocators, as well as the secretion and translocation of T3SS effectors, but did not influence their intracellular protein levels in E. tarda. Complementation of the escE mutant with a secretion-incompetent EscE derivative restored the secretion of translocators and effectors. Interestingly, the effectors that were secreted and translocated were positively correlated with the EscE protein level in E. tarda. The escE mutant was attenuated in the blue gourami fish infection model, as its 50% lethal dose (LD50) increased to 4 times that of the wild type. The survival rate of the escE mutant-strain-infected fish was 69%, which was much higher than that of the fish infected with the wild-type bacteria (6%). Overall, EscE represents a secreted T3SS regulator that controls effector injection and translocator secretion, thus contributing to E. tarda pathogenesis in fish. The homology of EscE within the T3SSs of other bacterial species suggests that the mechanism of secretion and translocation control used by E. tarda may be commonly used by other bacterial pathogens.
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Identification and functional characterization of the novel Edwardsiella tarda effector EseJ. Infect Immun 2015; 83:1650-60. [PMID: 25667268 DOI: 10.1128/iai.02566-14] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Edwardsiella tarda is a Gram-negative enteric pathogen that causes hemorrhagic septicemia in fish and gastro- and extraintestinal infections in humans. The type III secretion system (T3SS) of E. tarda has been identified as a key virulence factor that contributes to pathogenesis in fish. However, little is known about the associated effectors translocated by this T3SS. In this study, by comparing the profile of secreted proteins of the wild-type PPD130/91 and its T3SS ATPase ΔesaN mutant, we identified a new effector by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. This effector consists of 1,359 amino acids, sharing high sequence similarity with Orf29/30 of E. tarda strain EIB202, and is renamed EseJ. The secretion and translocation of EseJ depend on the T3SS. A ΔeseJ mutant strain adheres to epithelioma papillosum of carp (EPC) cells 3 to 5 times more extensively than the wild-type strain does. EseJ inhibits bacterial adhesion to EPC cells from within bacterial cells. Importantly, the ΔeseJ mutant strain does not replicate efficiently in EPC cells and fails to replicate in J774A.1 macrophages. In infected J774A.1 macrophages, the ΔeseJ mutant elicits higher production of reactive oxygen species than wild-type E. tarda. The replication defect is consistent with the attenuation of the ΔeseJ mutant in the blue gourami fish model: the 50% lethal dose (LD50) of the ΔeseJ mutant is 2.34 times greater than that of the wild type, and the ΔeseJ mutant is less competitive than the wild type in mixed infection. Thus, EseJ represents a novel effector that contributes to virulence by reducing bacterial adhesion to EPC cells and facilitating intracellular bacterial replication.
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Song M, Xie J, Peng X, Li H. Identification of protective immunogens from extracellular secretome of Edwardsiella tarda. FISH & SHELLFISH IMMUNOLOGY 2013; 35:1932-1936. [PMID: 24099803 DOI: 10.1016/j.fsi.2013.09.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Revised: 09/22/2013] [Accepted: 09/25/2013] [Indexed: 06/02/2023]
Abstract
Edwardsiella tarda is an opportunistic pathogen that causes a great loss in aquaculture. Identification of immune protective immunogens is a key step for development of subunit vaccines and control of the infectious diseases caused by the bacterium. This study aims to identify the protective antigens from extracellular secretory proteome of E. tarda. Out of 38 extracellular secretory proteins predicted by PSORTb, 20 genes were randomly cloned and their recombinant proteins were expressed in Escherichia coli BL21 and purified by either affinity chromatography or inclusion body washing. The purified recombinant proteins were used for investigation of immune protection in zebrafish model using active immunization approach. Half of them had significant immune protection compared with the control. Out of them, four, EseC, ETAE_2088, FlgD and ETAE_2130, showed approximately 60% relative percent survivals as a result of the highly protective antigens identified. Except for FlgD, the other three were first reported here. Moreover, the present study identified EseC and ETAE_2088 in bacterial extracellular fraction. These results indicate that secretory proteome is an interesting pool used for identification of immune protective antigens, and the four highly protective antigens identified provide useful candidates for development of subunit vaccines.
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Affiliation(s)
- Ming Song
- Center for Proteomics and Metabolomics, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, MOE Key Lab Aquat Food Safety, Guangzhou 510275, People's Republic of China
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Xiao J, Chen T, Liu B, Yang W, Wang Q, Qu J, Zhang Y. Edwardsiella tarda mutant disrupted in type III secretion system and chorismic acid synthesis and cured of a plasmid as a live attenuated vaccine in turbot. FISH & SHELLFISH IMMUNOLOGY 2013; 35:632-641. [PMID: 23732848 DOI: 10.1016/j.fsi.2013.05.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 05/18/2013] [Accepted: 05/18/2013] [Indexed: 06/02/2023]
Abstract
Edwardsiella tarda is an intractable Gram-negative pathogen in many fish species to cause edwardsiellosis. Its infection leads to extensive losses in a diverse array of commercially important fish. The type III secretion system (T3SS) has been considered as one of the major virulence factors and plays important roles in its intracellular lifestyle. In this study, an E. tarda EIB202 mutant WED with deletions in the T3SS genes for EseB, EseC, EseD and EscA, along with the aroC gene for the biosynthesis of chorismic acid, as well as the curing of endogenous plasmid pEIB202 was constructed by allelic exchange strategy. Compared to the wild-type EIB202 which was highly virulent towards turbot (Scophthamus maximus) via intraperitoneal (i.p.), intramuscular (i.m.) injection or immersion and caused systemic infection in turbot as well as the unexpected red mouth symptom when immersion challenged, WED was highly attenuated when inoculated into turbot via i.m., i.p. and immersion routes, and exhibited significantly impaired capacity to survive in fish tissues. WED showed 5700-fold higher 50% lethal dose (LD50) than that of the wild type when i.m. or i.p. challenged. Inoculation with WED by i.p. or immersion injection routes elicited significant protection against the challenge of the wild-type E. tarda after 5 weeks of vaccination. The vaccinated fish produced low while significant level of specific antibody and showed increased expression of immune-related factors including IL-1β, IFN-γ, MHC II, MHC-I and CD8, indicating that WED possesses significant immunoprotective potential. Furthermore, our data indicated that a single dose of i.p. and immersion vaccination with WED could produce significant protection as long as 12 and 6 months, respectively. These results demonstrated the feasibility of WED as a live attenuated vaccine in turbot against edwardsiellosis by immersion or i.p. injection routes.
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Affiliation(s)
- Jingfan Xiao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, PR China
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Leptospiral outer membrane protein LipL41 is not essential for acute leptospirosis but requires a small chaperone protein, lep, for stable expression. Infect Immun 2013; 81:2768-76. [PMID: 23690405 DOI: 10.1128/iai.00531-13] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Leptospirosis is a worldwide zoonosis caused by pathogenic Leptospira spp., but knowledge of leptospiral pathogenesis remains limited. However, the development of mutagenesis systems has allowed the investigation of putative virulence factors and their involvement in leptospirosis. LipL41 is the third most abundant lipoprotein found in the outer membranes of pathogenic leptospires and has been considered a putative virulence factor. LipL41 is encoded on the large chromosome 28 bp upstream of a small open reading frame encoding a hypothetical protein of unknown function. This gene was named lep, for LipL41 expression partner. In this study, lipL41 was found to be cotranscribed with lep. Two transposon mutants were characterized: a lipL41 mutant and a lep mutant. In the lep mutant, LipL41 protein levels were reduced by approximately 90%. Lep was shown through cross-linking and coexpression experiments to bind to LipL41. Lep is proposed to be a molecular chaperone essential for the stable expression of LipL41. The roles of LipL41 and Lep in the pathogenesis of Leptospira interrogans were investigated; surprisingly, neither of these two unique proteins was essential for acute leptospirosis.
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Phenotypic characterization, virulence, and immunogenicity of Edwardsiella tarda LSE40 aroA mutant. Appl Microbiol Biotechnol 2013; 97:6325-35. [DOI: 10.1007/s00253-013-4813-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 02/15/2013] [Accepted: 02/24/2013] [Indexed: 12/31/2022]
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Schreiner M, Niemann HH. Crystal structure of the Yersinia enterocolitica type III secretion chaperone SycD in complex with a peptide of the minor translocator YopD. BMC STRUCTURAL BIOLOGY 2012; 12:13. [PMID: 22708907 PMCID: PMC3443056 DOI: 10.1186/1472-6807-12-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 06/18/2012] [Indexed: 11/23/2022]
Abstract
Background Type III secretion systems are used by Gram-negative bacteria as “macromolecular syringes” to inject effector proteins into eukaryotic cells. Two hydrophobic proteins called translocators form the necessary pore in the host cell membrane. Both translocators depend on binding to a single chaperone in the bacterial cytoplasm to ensure their stability and efficient transport through the secretion needle. It was suggested that the conserved chaperones bind the more divergent translocators via a hexapeptide motif that is found in both translocators and conserved between species. Results We crystallized a synthetic decapeptide from the Yersinia enterocolitica minor type III secretion translocator YopD bound to its cognate chaperone SycD and determined the complex structure at 2.5 Å resolution. The structure of peptide-bound SycD is almost identical to that of apo SycD with an all helical fold consisting of three tetratricopeptide repeats (TPRs) and an additional C-terminal helix. Peptide-bound SycD formed a kinked head-to-head dimer that had previously been observed for the apo form of SycD. The homodimer interface comprises both helices of the first tetratricopeptide repeat. The YopD peptide bound in extended conformation into a mainly hydrophobic groove on the concave side of SycD. TPRs 1 and 2 of SycD form three hydrophobic pockets that accommodated the conserved hydrophobic residues at position 1, 3 and 6 of the translocator hexapeptide sequence. Two tyrosines that are highly conserved among translocator chaperones contribute to the hydrophobic patches but also form hydrogen bonds to the peptide backbone. Conclusions The interaction between SycD and YopD is very similar to the binding of the Pseudomonas minor translocator PopD to its chaperone PcrH and the Shigella major translocator IpaB to its chaperone IpgC. This confirms the prediction made by Kolbe and co-workers that a hexapeptide with hydrophobic residues at three positions is a conserved chaperone binding motif. Because the hydrophobic groove on the concave side of translocator chaperones is involved in binding of the major and the minor translocator, simultaneous binding of both translocators to a single type III secretion class II chaperone appears unlikely.
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Affiliation(s)
- Madeleine Schreiner
- Department of Chemistry, Bielefeld University, PO Box 10 01 31, 33501 Bielefeld, Germany
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Leung KY, Siame BA, Tenkink BJ, Noort RJ, Mok YK. Edwardsiella tarda – Virulence mechanisms of an emerging gastroenteritis pathogen. Microbes Infect 2012; 14:26-34. [DOI: 10.1016/j.micinf.2011.08.005] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 08/13/2011] [Accepted: 08/17/2011] [Indexed: 11/25/2022]
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Wang X, Wang Q, Yang M, Xiao J, Liu Q, Wu H, Zhang Y. QseBC controls flagellar motility, fimbrial hemagglutination and intracellular virulence in fish pathogen Edwardsiella tarda. FISH & SHELLFISH IMMUNOLOGY 2011; 30:944-953. [PMID: 21288493 DOI: 10.1016/j.fsi.2011.01.019] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 01/19/2011] [Accepted: 01/23/2011] [Indexed: 05/30/2023]
Abstract
The inter-kingdom communication with the mammalian hosts mediated by autoinducer-3 (AI-3)/epinephrine (Epi)/norepinephrine (NE), and transduced by two-component systems QseBC has recently been described. As a fish pathogen and opportunistic pathogen for human beings, Edwardsiella tarda develops surface structures such as flagellar and fimbriae to cause different hemagglutination phenotypes and serotypes and initiate pathogen-host recognition and invasion process. E. tarda survives within macrophages in fish using type III secretion system (TTSS). Here, the genes of E. tarda two-component system, qseB and qseC, were found to be co-transcribed. Phylogenetic analysis indicated that evolution of QseC strongly correlated to different host niches. Compared with the wild type and their complemented strains, ΔqseB and ΔqseC mutants exhibited significant impaired flagellar motilities. Mammalian Epi was able to stimuli the flagellar motility in E. tarda via QseBC. Hemagglutination caused by fimbriae was induced in ΔqseB but repressed in ΔqseC. Disruption of qseB or qseC down-regulated the intracellular expressions of TTSS elements EseB and EsaC, and impaired their intracellular survival capabilities as well as in vivo competitive abilities. Furthermore, in vitro tests indicated that expression of EseB was induced by Epi via QseBC. Our results revealed that the QseBC system modified the virulence-related surface structures (flagellum, fimbriae and secretion system) and that hormone might stimulate the virulence of the pathogen in fish.
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Affiliation(s)
- Xin Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China
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Li GY, Li J, Xiao P, Guo YH, Mo ZL. Detection of type III secretion gene as an indicator for pathogenic Edwardsiella tarda. Lett Appl Microbiol 2011; 52:213-9. [PMID: 21219368 DOI: 10.1111/j.1472-765x.2010.02984.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIMS To differentiate pathogenic and nonpathogenic Edwardsiella tarda strains based on the detection of type III secretion system (T3SS) gene using polymerase chain reaction (PCR). METHODS AND RESULTS Primers were designed to amplify Edw. tarda T3SS component gene esaV, catalase gene katB, haemolysin gene hlyA and 16S rRNA gene as an internal positive control. Genomic DNAs were extracted using a commercial isolation kit from 36 Edw. tarda strains consisting of 18 pathogenic and 18 nonpathogenic strains, and 50 ng of each DNA was used as the template for PCR amplification. PCR was performed with a thermocycler (TaKaRa TP600) in a 25-μl volume. Products of esaV were detected in all pathogenic strains, but not in nonpathogenic strains; katB was detected in all pathogenic strains and one of nonpathogenic strains; hlyA was not detected in any strains. CONCLUSIONS The detection of esaV gene can be used for the assessment of pathogenic Edw. tarda strains. SIGNIFICANCE AND IMPACT OF THE STUDY The strategy using T3SS gene as the virulence indicator provides a useful tool for the clinical assessment of pathogenic Edw. tarda strains and prediction of edwardsiellosis risk in fish culture environments.
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Affiliation(s)
- G Y Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
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Wang B, Mo ZL, Xiao P, Li J, Zou YX, Hao B, Li GY. EseD, a putative T3SS translocon component of Edwardsiella tarda, contributes to virulence in fish and is a candidate for vaccine development. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2010; 12:678-685. [PMID: 20072793 DOI: 10.1007/s10126-009-9255-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2009] [Accepted: 12/11/2009] [Indexed: 05/28/2023]
Abstract
Edwardsiella tarda has a type III secretion system (T3SS) essential for pathogenesis. EseD, together with EseB and EseC, has been suggested to form a putative T3SS translocon complex, although its further function is unclear. To investigate the physiological role of EseD, a mutant strain of E. tarda was constructed with an in-frame deletion of the entire eseD gene. One finding was that the ∆eseD mutant decreased the secretion levels of EseC and EseB proteins. Additionally, the ∆eseD mutant showed attenuated swarming and contact-hemolysis abilities. However, the ∆eseD mutant showed increased biofilm formation. Complementation of the mutant strain with eseD restored these phenotypes to those similar to the wild-type strain. Furthermore, infection experiments in fish showed that the ∆eseD mutant exhibited slower proliferation and a tenfold decrease in virulence in fish. These results indicate a specific role of EseD in the pathogenesis of E. tarda. Finally, recombinant EseD protein elicited high antibody titers in immunized fish and various levels of protection against lethal challenge with the wild-type strain. These results indicate that EseD protein may be a candidate antigen for development of a subunit vaccine against Edwardsiellosis.
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Affiliation(s)
- Bo Wang
- Key Lab of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China
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EseG, an effector of the type III secretion system of Edwardsiella tarda, triggers microtubule destabilization. Infect Immun 2010; 78:5011-21. [PMID: 20855515 DOI: 10.1128/iai.00152-10] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Edwardsiella tarda is a Gram-negative enteric pathogen that causes hemorrhagic septicemia in fish and both gastrointestinal and extraintestinal infections in humans. A type III secretion system (T3SS) was recently shown to contribute to pathogenesis, since deletions of various T3SS genes increased the 50% lethal dose (LD(50)) by about 1 log unit in the blue gourami infection model. In this study, we report EseG as the first identified effector protein of T3SS. EseG shares partial homology with two Salmonella T3SS effectors (SseG and SseF) over a conserved domain (amino acid residues 142 to 192). The secretion of EseG is dependent on a functional T3SS and, in particular, requires the chaperone EscB. Experiments using TEM-1 β-lactamase as a fluorescence-based reporter showed that EseG was translocated into HeLa cells at 35°C. Fractionation of infected HeLa cells demonstrated that EseG was localized to the host membrane fraction after translocation. EseG is able to disassemble microtubule structures when overexpressed in mammalian cells. This phenotype may require a conserved motif of EseG (EseG(142-192)), since truncated versions of EseG devoid of this motif lose their ability to cause microtubule destabilization. By demonstrating the function of EseG, our study contributes to the understanding of E. tarda pathogenesis. Moreover, the approach established in this study to identify type III effectors can be used to identify and characterize more type III and possible type VI effectors in Edwardsiella.
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