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Niu M, Sui Z, Jiang G, Wang L, Yao X, Hu Y. The Mutation of the DNA-Binding Domain of Fur Protein Enhances the Pathogenicity of Edwardsiella piscicida via Inducing Overpowering Pyroptosis. Microorganisms 2023; 12:11. [PMID: 38276180 PMCID: PMC10821184 DOI: 10.3390/microorganisms12010011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/30/2023] [Accepted: 12/12/2023] [Indexed: 01/27/2024] Open
Abstract
Edwardsiella piscicida is an important fish pathogen with a broad host that causes substantial economic losses in the aquaculture industry. Ferric uptake regulator (Fur) is a global transcriptional regulator and contains two typical domains, the DNA-binding domain and dimerization domain. In a previous study, we obtained a mutant strain of full-length fur of E. piscicida, TX01Δfur, which displayed increased siderophore production and stress resistance factors and decreased pathogenicity. To further reveal the regulatory mechanism of Fur, the DNA-binding domain (N-terminal) of Fur was knocked out in this study and the mutant was named TX01Δfur2. We found that TX01Δfur2 displayed increased siderophore production and enhanced adversity tolerance, including a low pH, manganese, and high temperature stress, which was consistent with the phenotype of TX01Δfur. Contrary to TX01Δfur, whose virulence was weakened, TX01Δfur2 displayed an ascended invasion of nonphagocytic cells and enhanced destruction of phagocytes via inducing overpowering or uncontrollable pyroptosis, which was confirmed by the fact that TX01Δfur2 induced higher levels of cytotoxicity, IL-1β, and p10 in macrophages than TX01. More importantly, TX01Δfur2 displayed an increased global virulence to the host, which was confirmed by the result that TX01Δfur2 caused higher lethality outcomes for healthy tilapias than TX01. These results demonstrate that the mutation of the Fur N-terminal domain augments the resistance level against the stress and pathogenicity of E. piscicida, which is not dependent on the bacterial number in host cells or host tissues, although the capabilities of biofilm formation and the motility of TX01Δfur2 decline. These interesting findings provide a new insight into the functional analysis of Fur concerning the regulation of virulence in E. piscicida and prompt us to explore the subtle regulation mechanism of Fur in the future.
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Affiliation(s)
- Mimi Niu
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China;
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; (G.J.); (L.W.)
- Key Laboratory of Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou 571101, China
- School of Life Sciences, Hainan University, Haikou 570228, China
| | - Zhihai Sui
- School of Life Science, Linyi University, Linyi 276000, China;
| | - Guoquan Jiang
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; (G.J.); (L.W.)
- Key Laboratory of Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou 571101, China
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Ling Wang
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; (G.J.); (L.W.)
- Key Laboratory of Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou 571101, China
- Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-Resources, Haikou 571101, China
| | - Xuemei Yao
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China;
- School of Marine Biology and Aquaculture, Hainan University, Haikou 570228, China
| | - Yonghua Hu
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; (G.J.); (L.W.)
- Key Laboratory of Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou 571101, China
- Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-Resources, Haikou 571101, China
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Conrad RA, Evenhuis JP, Lipscomb RS, Pérez-Pascual D, Stevick RJ, Birkett C, Ghigo JM, McBride MJ. Flavobacterium columnare ferric iron uptake systems are required for virulence. Front Cell Infect Microbiol 2022; 12:1029833. [PMID: 36325469 PMCID: PMC9618737 DOI: 10.3389/fcimb.2022.1029833] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Accepted: 09/28/2022] [Indexed: 11/24/2022] Open
Abstract
Flavobacterium columnare, which causes columnaris disease, is one of the costliest pathogens in the freshwater fish-farming industry. The virulence mechanisms of F. columnare are not well understood and current methods to control columnaris outbreaks are inadequate. Iron is an essential nutrient needed for metabolic processes and is often required for bacterial virulence. F. columnare produces siderophores that bind ferric iron for transport into the cell. The genes needed for siderophore production have been identified, but other components involved in F. columnare iron uptake have not been studied in detail. We identified the genes encoding the predicted secreted heme-binding protein HmuY, the outer membrane iron receptors FhuA, FhuE, and FecA, and components of an ATP binding cassette (ABC) transporter predicted to transport ferric iron across the cytoplasmic membrane. Deletion mutants were constructed and examined for growth defects under iron-limited conditions and for virulence against zebrafish and rainbow trout. Mutants with deletions in genes encoding outer membrane receptors, and ABC transporter components exhibited growth defects under iron-limited conditions. Mutants lacking multiple outer membrane receptors, the ABC transporter, or HmuY retained virulence against zebrafish and rainbow trout mirroring that exhibited by the wild type. Some mutants predicted to be deficient in multiple steps of iron uptake exhibited decreased virulence. Survivors of exposure to such mutants were partially protected against later infection by wild-type F. columnare.
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Affiliation(s)
- Rachel A. Conrad
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Jason P. Evenhuis
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture (USDA), Kearneysville, WV, United States
| | - Ryan S. Lipscomb
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture (USDA), Kearneysville, WV, United States
| | - David Pérez-Pascual
- Institut Pasteur, Université de Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Rebecca J. Stevick
- Institut Pasteur, Université de Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Clayton Birkett
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture (USDA), Kearneysville, WV, United States
| | - Jean-Marc Ghigo
- Institut Pasteur, Université de Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
- *Correspondence: Mark J. McBride,
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Jiang M, Hong K, Mao Y, Ma H, Chen T, Wang Z. Natural 5-Aminolevulinic Acid: Sources, Biosynthesis, Detection and Applications. Front Bioeng Biotechnol 2022; 10:841443. [PMID: 35284403 PMCID: PMC8913508 DOI: 10.3389/fbioe.2022.841443] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 01/20/2022] [Indexed: 12/02/2022] Open
Abstract
5-Aminolevulinic acid (5-ALA) is the key precursor for the biosynthesis of tetrapyrrole compounds, with wide applications in medicine, agriculture and other burgeoning fields. Because of its potential applications and disadvantages of chemical synthesis, alternative biotechnological methods have drawn increasing attention. In this review, the recent progress in biosynthetic pathways and regulatory mechanisms of 5-ALA synthesis in biological hosts are summarized. The research progress on 5-ALA biosynthesis via the C4/C5 pathway in microbial cells is emphasized, and the corresponding biotechnological design strategies are highlighted and discussed in detail. In addition, the detection methods and applications of 5-ALA are also reviewed. Finally, perspectives on potential strategies for improving the biosynthesis of 5-ALA and understanding the related mechanisms to further promote its industrial application are conceived and proposed.
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Affiliation(s)
- Meiru Jiang
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Kunqiang Hong
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Yufeng Mao
- Key Laboratory of System Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Hongwu Ma
- Key Laboratory of System Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Tao Chen
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Zhiwen Wang
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
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Du C, Huo X, Gu H, Wu D, Hu Y. Acid resistance system CadBA is implicated in acid tolerance and biofilm formation and is identified as a new virulence factor of Edwardsiella tarda. Vet Res 2021; 52:117. [PMID: 34521475 PMCID: PMC8438976 DOI: 10.1186/s13567-021-00987-x] [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: 05/27/2021] [Accepted: 07/27/2021] [Indexed: 11/10/2022] Open
Abstract
Edwardsiella tarda is a facultative intracellular pathogen in humans and animals. The Gram-negative bacterium is widely considered a potentially important bacterial pathogen. Adaptation to acid stress is important for the transmission of intestinal microbes, so the acid-resistance (AR) system is essential. However, the AR systems of E. tarda are totally unknown. In this study, a lysine-dependent acid resistance (LDAR) system in E. tarda, CadBA, was characterized and identified. CadB is a membrane protein and shares high homology with the lysine/cadaverine antiporter. CadA contains a PLP-binding core domain and a pyridoxal phosphate-binding motif. It shares high homology with lysine decarboxylase. cadB and cadA are co-transcribed under one operon. To study the function of the cadBA operon, isogenic cadA, cadB and cadBA deletion mutant strains TX01ΔcadA, TX01ΔcadB and TX01ΔcadBA were constructed. When cultured under normal conditions, the wild type strain and three mutants exhibited the same growth performance. However, when cultured under acid conditions, the growth of three mutants, especially TX01ΔcadA, were obviously retarded, compared to the wild strain TX01, which indicates the important involvement of the cadBA operon in acid resistance. The deletion of cadB or cadA, especially cadBA, significantly attenuated bacterial activity of lysine decarboxylase, suggesting the vital participation of cadBA operon in lysine metabolism, which is closely related to acid resistance. The mutations of cadBA operon enhanced bacterial biofilm formation, especially under acid conditions. The deletions of the cadBA operon reduced bacterial adhesion and invasion to Hela cells. Consistently, the deficiency of cadBA operon abated bacterial survival and replication in macrophages, and decreased bacterial dissemination in fish tissues. Our results also show that the expression of cadBA operon and regulator cadC were up-regulated upon acid stress, and CadC rigorously regulated the expression of cadBA operon, especially under acid conditions. These findings demonstrate that the AR CadBA system was a requisite for the resistance of E. tarda against acid stress, and played a critical role in bacterial infection of host cells and in host tissues. This is the first study about the acid resistance system of E. tarda and provides new insights into the acid-resistance mechanism and pathogenesis of E. tarda.
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Affiliation(s)
- Chunmei Du
- College of Basic Medicine, Jiamusi University, 154007, Jiamusi, China.,Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, CATAS, 571101, Haikou, China.,College of Life Science, Jiamusi University, 154007, Jiamusi, China
| | - Xiaoping Huo
- Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, CATAS, 571101, Haikou, China.,College of Life Science, Jiamusi University, 154007, Jiamusi, China
| | - Hanjie Gu
- Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, CATAS, 571101, Haikou, China.,Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-Resources, 571101, Haikou, China
| | - Dongmei Wu
- College of Basic Medicine, Jiamusi University, 154007, Jiamusi, China. .,Heilongjiang Provincial Key Laboratory of New Drug Development and Evaluation of the Efficacy of Toxicology, 154007, Jiamusi, China.
| | - Yonghua Hu
- Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, CATAS, 571101, Haikou, China. .,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), 266071, Qingdao, China. .,College of Life Science, Jiamusi University, 154007, Jiamusi, China. .,Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-Resources, 571101, Haikou, China.
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Liu J, Tian Y, Zhao Y, Zeng R, Chen B, Hu B, Walcott RR. Ferric Uptake Regulator (FurA) is Required for Acidovorax citrulli Virulence on Watermelon. PHYTOPATHOLOGY 2019; 109:1997-2008. [PMID: 31454303 DOI: 10.1094/phyto-05-19-0172-r] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Acidovorax citrulli is the causal agent of bacterial fruit blotch, a serious threat to commercial watermelon and melon crop production worldwide. Ferric uptake regulator (Fur) is a global transcription factor that affects a number of virulence-related functions in phytopathogenic bacteria; however, the role of furA has not been determined for A. citrulli. Hence, we constructed an furA deletion mutant and a corresponding complement in the background of A. citrulli strain xlj12 to investigate the role of the gene in siderophore production, concentration of intracellular Fe2+, bacterial sensitivity to hydrogen peroxide, biofilm formation, swimming motility, hypersensitive response induction, and virulence on melon seedlings. The A. citrulli furA deletion mutant displayed increased siderophore production, intracellular Fe2+ concentration, and increased sensitivity to hydrogen peroxide. In contrast, biofilm formation, swimming motility, and virulence on melon seedlings were significantly reduced in the furA mutant. As expected, complementation of the furA deletion mutant restored all phenotypes to wild-type levels. In accordance with the phenotypic results, the expression levels of bfrA and bfrB that encode bacterioferritin, sodB that encodes iron/manganese superoxide dismutase, fliS that encodes a flagellar protein, hrcN that encodes the type III secretion system (T3SS) ATPase, and hrcC that encodes the T3SS outer membrane ring protein were significantly downregulated in the A. citrulli furA deletion mutant. In addition, the expression of feo-related genes and feoA and feoB was significantly upregulated in the furA mutant. Overall, these results indicated that, in A. citrulli, FurA contributes to the regulation of the iron balance system, and affects a variety of virulence-related traits.
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Affiliation(s)
- Jun Liu
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China
| | - Yanli Tian
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuqiang Zhao
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China
| | - Rong Zeng
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China
| | - Baohui Chen
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China
| | - Baishi Hu
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China
| | - Ron R Walcott
- Department of Plant Pathology, 4315 Miller Plant Sciences, the University of Georgia, Athens, GA 30602, U.S.A
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Shi YJ, Fang QJ, Huang HQ, Gong CG, Hu YH. HutZ is required for biofilm formation and contributes to the pathogenicity of Edwardsiella piscicida. Vet Res 2019; 50:76. [PMID: 31578154 PMCID: PMC6775658 DOI: 10.1186/s13567-019-0693-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 08/19/2019] [Indexed: 12/13/2022] Open
Abstract
Edwardsiella piscicida is a severe fish pathogen. Haem utilization systems play an important role in bacterial adversity adaptation and pathogenicity. In this study, a speculative haem utilization protein, HutZEp, was characterized in E. piscicida. hutZEp is encoded with two other genes, hutW and hutX, in an operon that is similar to the haem utilization operon hutWXZ identified in V. cholerae. However, protein activity analysis showed that HutZEp is probably not related to hemin utilization. To explore the biological role of HutZEp, a markerless hutZEp in-frame mutant strain, TX01ΔhutZ, was constructed. Deletion of hutZEp did not significantly affect bacterial growth in normal medium, in iron-deficient conditions, or in the presence of haem but significantly retarded bacterial biofilm growth. The expression of known genes related to biofilm growth was not affected by hutZEp deletion, which indicated that HutZEp was probably a novel factor promoting biofilm formation in E. piscicida. Compared to the wild-type TX01, TX01ΔhutZ exhibited markedly compromised tolerance to acid stress and host serum stress. Pathogenicity analysis showed that inactivation of hutZEp significantly impaired the ability of E. piscicida to invade and reproduce in host cells and to infect host tissue. In contrast to TX01, TX01ΔhutZ was defective in blocking host macrophage activation. The expression of hutZEp was directly regulated by the ferric uptake regulator Fur. This study is the first functional characterization of HutZ in a fish pathogen, and these findings suggested that HutZEp is essential for E. piscicida biofilm formation and contributes to host infection.
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Affiliation(s)
- Yan-Jie Shi
- Ocean College of Hebei Agricultural University, Qinhuangdao, 066000, China.,Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China
| | - Qing-Jian Fang
- Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China
| | - Hui-Qin Huang
- Ocean College of Hebei Agricultural University, Qinhuangdao, 066000, China.,Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China.,Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Haikou, 571101, China
| | - Chun-Guang Gong
- Ocean College of Hebei Agricultural University, Qinhuangdao, 066000, China.
| | - Yong-Hua Hu
- Ocean College of Hebei Agricultural University, Qinhuangdao, 066000, China. .,Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China. .,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China. .,Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Haikou, 571101, China.
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Liu H, Song T, Lv T, Zhao X, Shao Y, Li C, Zhang W. Cu2+ regulated sulfonamides resistance gene (sul) via reactive oxygen species induced ArcA in a pathogenic Vibrio splendidus. ANN MICROBIOL 2019. [DOI: 10.1007/s13213-019-01475-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Thioredoxin H (TrxH) contributes to adversity adaptation and pathogenicity of Edwardsiella piscicida. Vet Res 2019; 50:26. [PMID: 30992061 PMCID: PMC6466703 DOI: 10.1186/s13567-019-0645-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 02/26/2019] [Indexed: 12/11/2022] Open
Abstract
Thioredoxins (Trxs) play an important role in defending against oxidative stress and keeping disulfide bonding correct to maintain protein function. Edwardsiella piscicida, a severe fish pathogen, has been shown to encode several thioredoxins including TrxA, TrxC, and TrxH, but their biological roles remain unknown. In this study, we characterized TrxH of E. piscicida (named TrxHEp) and examined its expression and function. TrxHEp is composed of 125 residues and possesses typical thioredoxin H motifs. Expression of trxHEp was upregulated under conditions of oxidative stress, iron starvation, low pH, and during infection of host cells. trxHEp expression was also regulated by ferric uptake regulator (Fur), an important global regulatory of E. piscicida. Compared to the wild type TX01, a markerless trxHEp in-frame mutant strain TX01∆trxH exhibited markedly compromised tolerance of the pathogen to hydrogen peroxide, acid stress, and iron deficiency. Deletion of trxHEp significantly retarded bacterial biofilm growth and decreased resistance against serum killing. Pathogenicity analysis shows that the inactivation of trxHEp significantly impaired the ability of E. piscicida to invade host cells, reproduce in macrophages, and infect host tissues. Introduction of a trans-expressed trxH gene restored the lost virulence of TX01∆trxH. There is likely to be a complex relationship of functional complementation or expression regulation between TrxH and another two thioredoxins, TrxA and TrxC, of E. piscicida. This is the first functional report of TrxH in fish pathogens, and the findings suggest that TrxHEp is essential for coping with adverse circumstances and contributes to host infection of E. piscicida.
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Sarvan S, Butcher J, Stintzi A, Couture JF. Variation on a theme: investigating the structural repertoires used by ferric uptake regulators to control gene expression. Biometals 2018; 31:681-704. [DOI: 10.1007/s10534-018-0120-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 06/12/2018] [Indexed: 11/29/2022]
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Hu YH, Sun L. The global regulatory effect of Edwardsiella tarda Fur on iron acquisition, stress resistance, and host infection: A proteomics-based interpretation. J Proteomics 2016; 140:100-10. [PMID: 27102497 DOI: 10.1016/j.jprot.2016.04.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/27/2016] [Accepted: 04/07/2016] [Indexed: 02/01/2023]
Abstract
UNLABELLED Ferric uptake regulator (Fur) is an important transcriptional regulator of Gram-negative bacteria. Edwardsiella tarda is a severe fish bacterial pathogen with a broad host range that includes humans. In this study, we examined the regulatory function of Fur in E. tarda via a proteomic approach. Compared to the wild type TX01, the fur mutant TX01Δfur exhibited (i) retarded growth, (ii) enhanced siderophore production, (iii) increased acid tolerance, which is in contrast to observations in other bacterial species, (iv) decreased survival against oxidative stress and host serum, (v) impaired ability to inhibit host immune response, (vi) attenuated tissue infectivity and overall virulence. The deficiency of TX01Δfur was rescued by introduction of an exogenous fur gene. iTRAQ-based comparative proteomic analysis of TX01Δfur and TX01 identified 89 differentially expressed proteins that cover a wide range of functional categories including those affected by fur mutation. In addition, 16 proteins were identified for the first time to be regulated by Fur in Gram-negative bacteria. These results provide the first protein-based interpretation of the global impact of Fur on the physiology and infectivity of E. tarda. SIGNIFICANCE This study demonstrates that in E. tarda, Fur controls multiple aspects of bacterial life, including growth, metabolism, iron acquisition, stress response, and host infection. In line with these observations, proteomics analysis identified a large amount of proteins affected in expression by Fur, which are involved in bacterial physiology and infectivity. Hence, these results link for the first time the pleiotropic effect of Fur with global protein expression and shed new light on the function and regulatory mechanism of Fur in pathogenic bacteria.
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Affiliation(s)
- Yong-Hua Hu
- 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
| | - Li Sun
- 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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Functional Analysis of the Ferric Uptake Regulator Gene fur in Xanthomonas vesicatoria. PLoS One 2016; 11:e0149280. [PMID: 26910324 PMCID: PMC4766189 DOI: 10.1371/journal.pone.0149280] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 01/29/2016] [Indexed: 11/19/2022] Open
Abstract
Iron is essential for the growth and survival of many organisms. Intracellular iron homeostasis must be maintained for cell survival and protection against iron toxicity. The ferric uptake regulator protein (Fur) regulates the high-affinity ferric uptake system in many bacteria. To investigate the function of the fur gene in Xanthomonas vesicatoria (Xv), we generated a fur mutant strain, fur-m, by site-directed mutagenesis. Whereas siderophore production increased in the Xv fur mutant, extracellular polysaccharide production, biofilm formation, swimming ability and quorum sensing signals were all significantly decreased. The fur mutant also had significantly reduced virulence in tomato leaves. The above-mentioned phenotypes significantly recovered when the Xv fur mutation allele was complemented with a wild-type fur gene. Thus, Fur either negatively or positively regulates multiple important physiological functions in Xv.
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Interplay between iron homeostasis and virulence: Fur and RyhB as major regulators of bacterial pathogenicity. Vet Microbiol 2015; 179:2-14. [PMID: 25888312 DOI: 10.1016/j.vetmic.2015.03.024] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/23/2015] [Accepted: 03/25/2015] [Indexed: 11/21/2022]
Abstract
In bacteria-host interactions, competition for iron is critical for the outcome of the infection. As a result of its redox properties, this metal is essential for the growth and proliferation of most living organisms, including pathogenic bacteria. This metal is also potentially toxic, making the precise maintenance of iron homeostasis necessary for survival. Iron acquisition and storage control is mediated in most bacteria by the global ferric uptake regulator (Fur) and iron-responsive small regulatory non-coding RNAs (RyhB in the model organism Escherichia coli). While the role of these regulators in iron homeostasis is well documented in both pathogenic and non-pathogenic bacteria, many recent studies also demonstrate that these regulators are involved in the virulence of pathogenic bacteria. By sensing iron availability in the environment, Fur and RyhB are able to regulate, either directly or indirectly via other transcriptional regulators or modulation of intracellular iron concentration, many virulence determinants of pathogenic bacteria. Iron is thus both a nutritional and regulatory element, allowing bacteria to adapt to various host environments by adjusting expression of virulence factors. In this review, we present evidences that Fur and RyhB are the major regulators of this adaptation, as they are involved in diverse functions ranging from iron homeostasis to regulation of virulence by mediating key pathogen responses such as invasion of eukaryotic cells, toxin production, motility, quorum sensing, stress resistance or biofilm formation. Therefore, Fur and RyhB play a major role in regulating an adaptative response during bacterial infections, making them important targets in the fight against pathogenic bacteria.
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Menanteau-Ledouble S, Kattlun J, Nöbauer K, El-Matbouli M. Protein expression and transcription profiles of three strains of Aeromonas salmonicida ssp. salmonicida under normal and iron-limited culture conditions. Proteome Sci 2014; 12:29. [PMID: 24872729 PMCID: PMC4035829 DOI: 10.1186/1477-5956-12-29] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 04/29/2014] [Indexed: 11/25/2022] Open
Abstract
Background Aeromonas salmonicida is an important fish pathogen that produces a wide and varied array of virulence factors. Here we used iron deprivation by addition of the chelator 2’2-dipyridyl to induce the expression of several such virulence factors in three isolates of Aeromonas salmonicida (one avirulent and two virulent). By using SDS-PAGE followed by mass spectrometry, we identified proteins that appeared differentially expressed under these conditions. The differential transcription of the identified gene products were subsequently measured by reverse transcription quantitative real-time PCR (RT-qPCR). Results Our initial screening using SDS-PAGE identified five proteins that appeared differentially expressed in virulent and avirulent isolates or, within the same isolates, between bacteria cultivated under iron-rich or iron-deprived conditions. The transcription of the genes coding for these proteins were subsequently quantified by RT-qPCR. Results of this analysis demonstrated that the gene coding for alkyl hydroperoxide reductase (AhpC), a protein involved in oxidative stress response, was transcribed at a higher rate in the virulent strain as compared to the avirulent strain. Additionally, it was observed that addition of an iron chelator to the culture medium lead to a reduction of the transcription levels of the regulatory histone-like nucleoid structuring protein (H-NS). This was consistent in all three isolates. On the other hand, the transcription levels of the virulence array protein (VapA) and the protein ATP-synthetase F (ATPF) displayed only limited changes, despite being the dominant component of a protein fraction that displayed changes during the preliminary SDS-PAGE screening. This was true regardless of the culture conditions and of the isolates considered. Finally, transcription of the enzyme enolase was upregulated in the iron-deprived broths in all isolates. Conclusions We identified several genes differentially expressed under culture conditions known to lead to the overexpression of virulence factors. In addition, we identified alkyl hydroperoxide as being overexpressed in the virulent isolates compared to the avirulent isolates. The results from this study will contribute to enhance our understanding of the virulence of A. salmonicida and may suggest new directions for further research.
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Affiliation(s)
- Simon Menanteau-Ledouble
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, Vienna 1210, Austria
| | - Julia Kattlun
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, Vienna 1210, Austria
| | - Katharina Nöbauer
- VetCore Facility for Research, University of Veterinary Medicine, Vienna, Austria
| | - Mansour El-Matbouli
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, Vienna 1210, Austria
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Kim K, Kang J, Park J, Joh S, Lee H, Kwon Y. Phenotypic traits, virulence-associated gene profile and genetic relatedness of Edwardsiella tarda
isolates from Japanese eel Anguilla japonica
in Korea. Lett Appl Microbiol 2013; 58:168-76. [DOI: 10.1111/lam.12172] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Revised: 09/27/2013] [Accepted: 10/02/2013] [Indexed: 12/26/2022]
Affiliation(s)
- K.I. Kim
- Avian Disease Division; Animal and Plant Quarantine Agency; Anyang Gyeonggi Korea
| | - J.Y. Kang
- Avian Disease Division; Animal and Plant Quarantine Agency; Anyang Gyeonggi Korea
| | - J.Y. Park
- Avian Disease Division; Animal and Plant Quarantine Agency; Anyang Gyeonggi Korea
| | - S.J. Joh
- Avian Disease Division; Animal and Plant Quarantine Agency; Anyang Gyeonggi Korea
| | - H.S. Lee
- Avian Disease Division; Animal and Plant Quarantine Agency; Anyang Gyeonggi Korea
| | - Y.K. Kwon
- Avian Disease Division; Animal and Plant Quarantine Agency; Anyang Gyeonggi Korea
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15
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Role of Fur on cyanide tolerance of Pseudomonas pseudoalcaligenes CECT5344. Biochem Soc Trans 2011; 39:1854-8. [DOI: 10.1042/bst20110706] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Pseudomonas pseudoalcaligenes CECT5344 can be used in cyanide bioremediation processes because it grows at pH 9.5 using 2.0 mM cyanide at the sole nitrogen source. Cyanide strongly binds to metals creating iron-deprivation conditions. The bacterium responds to the presence of cyanide by inducing several processes such as siderophore synthesis for iron capture, cyanide-insensitive respiration system and defence mechanisms against oxidative stress. Since high concentrations of cyanide cause iron deficiency and because iron is an essential nutrient, bacterial growth in the presence of cyanide requires an efficient iron uptake. Fur is a global transcription factor that regulates a diversity of biological processes such as iron homoeostasis, TCA (tricarboxylic acid) cycle metabolism and oxidative stress response. Fur's regulation of iron uptake and storage genes should play a significant role in the lives of these bacteria. In the present review, current knowledge of Fur is summarized.
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Chakraborty S, Sivaraman J, Leung KY, Mok YK. Two-component PhoB-PhoR regulatory system and ferric uptake regulator sense phosphate and iron to control virulence genes in type III and VI secretion systems of Edwardsiella tarda. J Biol Chem 2011; 286:39417-30. [PMID: 21953460 DOI: 10.1074/jbc.m111.295188] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Inorganic phosphate (P(i)) and iron are essential nutrients that are depleted by vertebrates as a protective mechanism against bacterial infection. This depletion, however, is sensed by some pathogens as a signal to turn on the expression of virulence genes. Here, we show that the PhoB-PhoR two-component system senses changes in P(i) concentration, whereas the ferric uptake regulator (Fur) senses changes in iron concentration in Edwardsiella tarda PPD130/91 to regulate the expression of type III and VI secretion systems (T3SS and T6SS) through an E. tarda secretion regulator, EsrC. In sensing low P(i) concentration, PhoB-PhoR autoregulates and activates the phosphate-specific transport operon, pstSCAB-phoU, by binding directly to the Pho box in the promoters of phoB and pstS. PhoB also binds with EsrC simultaneously on the promoter of an E. tarda virulence protein, evpA, to regulate directly the transcription of genes from T6SS. In addition, PhoB requires and interacts with PhoU to activate esrC and suppress fur indirectly through unidentified regulators. Fur, on the other hand, senses high iron concentration and binds directly to the Fur box in the promoter of evpP to inhibit EsrC binding to the same region. In addition, Fur suppresses transcription of phoB, pstSCAB-phoU, and esrC indirectly via unidentified regulators, suggesting negative cross-talk with the Pho regulon. Physical interactions exist between Fur and PhoU and between Fur and EsrC. Our findings suggest that T3SS and T6SS may carry out distinct roles in the pathogenicity of E. tarda by responding to different environmental factors.
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Affiliation(s)
- Smarajit Chakraborty
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543, Singapore
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17
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González A, Bes MT, Barja F, Peleato ML, Fillat MF. Overexpression of FurA in Anabaena sp. PCC 7120 Reveals New Targets for This Regulator Involved in Photosynthesis, Iron Uptake and Cellular Morphology. ACTA ACUST UNITED AC 2010; 51:1900-14. [DOI: 10.1093/pcp/pcq148] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18
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Isolation and analysis of the vaccine potential of an attenuated Edwardsiella tarda strain. Vaccine 2010; 28:6344-50. [PMID: 20637307 DOI: 10.1016/j.vaccine.2010.06.101] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 06/26/2010] [Accepted: 06/29/2010] [Indexed: 11/21/2022]
Abstract
Edwardsiella tarda is an important aquaculture pathogen that can infect a wide range of marine and freshwater fish worldwide. In this study, a modified E. tarda strain, TX5RM, was selected by multiple passages of the pathogenic E. tarda strain TX5 on growth medium containing the antibiotic rifampicin. Compared to the wild type strain, the rifampicin-resistant mutant TX5RM (i) shows drastically increased median lethal dose and reduced capacity to disseminate in and colonize fish tissues and blood; (ii) exhibits slower growth rates when cultured in rich medium or under conditions of iron depletion; and (iii) differs in the production profile of whole-cell proteins. The immunoprotective potential of TX5RM was examined in a Japanese flounder (Paralichthys olivaceus) model as a vaccine delivered via intraperitoneal injection, oral feeding, bath immersion, and oral feeding plus immersion. All the vaccination trials, except those of injection, were performed with a booster at 3-week after the first vaccination. The results showed that TX5RM administered via all four approaches produced significant protection, with the highest protection levels observed with TX5RM administered via oral feeding plus immersion, which were, in terms of relative percent of survival (RPS), 80.6% and 69.4% at 5- and 8-week post-vaccination, respectively. Comparable levels of specific serum antibody production were induced by TX5RM-vaccinated via different routes. Microbiological analyses showed that TX5RM was recovered from the gut, liver, and spleen of the fish at 1-10 days post-oral vaccination and from the spleen, liver, kidney, and blood of the fish at 1-14 days post-immersion vaccination. Taken together, these results indicate that TX5RM is an attenuated E. tarda strain with good vaccine potential and that a combination of oral and immersion vaccinations may be a good choice for the administration of live attenuated vaccines.
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19
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RmpA regulation of capsular polysaccharide biosynthesis in Klebsiella pneumoniae CG43. J Bacteriol 2010; 192:3144-58. [PMID: 20382770 DOI: 10.1128/jb.00031-10] [Citation(s) in RCA: 163] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sequence analysis of the large virulence plasmid pLVPK in Klebsiella pneumoniae CG43 revealed the presence of another mucoid factor encoding gene rmpA besides rmpA2. Promoter activity measurement indicated that the deletion of rmpA reduced K2 capsular polysaccharide (CPS) biosynthesis, resulting in decreased colony mucoidy and virulence in mice. Introduction of a multicopy plasmid carrying rmpA restored CPS production in the rmpA or rmpA2 mutant but not in the rcsB mutant. Transformation of the rmpA deletion mutant with an rcsB-carrying plasmid also failed to enhance CPS production, suggesting that a cooperation of RmpA with RcsB is required for regulatory activity. This was further corroborated by the demonstration of in vivo interaction between RmpA and RcsB using two-hybrid analysis and coimmunoprecipitation analysis. A putative Fur binding box was only found at the 5' noncoding region of rmpA. The promoter activity analysis indicated that the deletion of fur increased the rmpA promoter activity. Using electrophoretic mobility shift assay, we further demonstrated that Fur exerts its regulatory activity by binding directly to the promoter. As a result, the fur deletion mutant exhibited an increase in colony mucoidy, CPS production, and virulence in mice. In summary, our results suggested that RmpA activates CPS biosynthesis in K. pneumoniae CG43 via an RcsB-dependent manner. The expression of rmpA is regulated by the availability of iron and is negatively controlled by Fur.
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20
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Mutations of ferric uptake regulator (fur) impair iron homeostasis, growth, oxidative stress survival, and virulence of Xanthomonas campestris pv. campestris. Arch Microbiol 2010; 192:331-9. [DOI: 10.1007/s00203-010-0558-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 02/10/2010] [Accepted: 02/15/2010] [Indexed: 10/19/2022]
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21
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Sun K, Cheng S, Wang F, Sun L. Domain analysis of the Edwardsiella tarda ferric uptake regulator. J GEN APPL MICROBIOL 2009; 55:351-8. [PMID: 19940381 DOI: 10.2323/jgam.55.351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Recent studies have shown that the ferric uptake regulator (Fur) of Edwardsiella tarda (Fur(Et)) shares high sequence identity with the Escherichia coli Fur (Fur(Ec)) at the N-terminal DNA-binding region. In the present study, the functional importance of the C-terminal region of Fur(Et) was investigated. It was found that Fur(Et) bearing deletion of the C-terminal 12 residues still possesses most of the repressor activity, whereas Fur(Et) bearing deletions of the C-terminal 16 and more than 16 residues are severely affected in activity. Domain swapping analyses indicated that the chimeric Fur proteins (Et75Ec73 and Et75Vh74) consisting of the N-terminal 1-75 region of Fur(Et) fused to the C-terminal 76-148 region of Fur(Ec) and the C-terminal 76-149 region of the Vibrio harveyi Fur (Fur(Vh)), respectively, are fully active. C92 of Fur(Ec) and C137 of Fur(Vh), which are functionally essential in Fur(Ec) and Fur(Vh), respectively, are also essential in Et75Ec73 and Et75Vh74, respectively. Further study identified an artificial Fur protein, EtMF54, which is composed of the N-terminal 49 residues of Fur(Et) and five artificial residues. Compared to Fur(Et), EtMF54 possesses partial Fur activity that is iron-dependent. These results (i) indicate that there exist certain functional/structural compatibilities among Fur(Et), Fur(Ec), and Fur(Vh) at the C-terminal region; (ii) provide insights to the potential location of the regulatory ion-binding site of Fur(Et).
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Affiliation(s)
- Kun Sun
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, PR China
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22
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Jiao XD, Dang W, Hu YH, Sun L. Identification and immunoprotective analysis of an in vivo-induced Edwardsiella tarda antigen. FISH & SHELLFISH IMMUNOLOGY 2009; 27:633-638. [PMID: 19706328 DOI: 10.1016/j.fsi.2009.08.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2009] [Revised: 08/10/2009] [Accepted: 08/10/2009] [Indexed: 05/28/2023]
Abstract
Edwardsiella tarda is a severe aquaculture pathogen that can infect many important fish species cultured worldwide. The aim of this study was to evaluate the vaccine potential of an E. tarda antigen, Eta21, which was identified from a pathogenic E. tarda strain via the method of in vivo-induced antigen technology (IVIAT). Eta21 is 510-amino acid in length and shares approximately 58% sequence identity with a putative peptidase of several bacterial species. eta21 was subcloned into Escherichia coli, and recombinant Eta21 was purified as a histidine-tagged protein. When used as a subunit vaccine, purified recombinant Eta21 was effective against lethal E. tarda challenge in a Japanese flounder model. In order to improve the immunoprotective efficacy of Eta21, the chimera AgaV-Eta21 was constructed, which consists of Eta21 fused in-frame to the secretion domain of AgaV, an extracellular beta-agarase. E. coli DH5alpha harboring plasmid pTAET21, which constitutively expresses agaV-eta21, was able to produce and secret AgaV-Eta21 into the extracellular milieu. Vaccination of Japanese flounder with live DH5alpha/pTAET21 elicited immunoprotection that is significantly higher in level than that induced by vaccination with purified recombinant Eta21. Vaccination with DH5alpha/pTAET21 and recombinant Eta21 both induced the production of specific serum antibodies at four to eight weeks post-vaccination. Taken together, these results demonstrate that Eta21, especially that delivered by DH5alpha/pTAET21, is an effective vaccine candidate against E. tarda infection.
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Affiliation(s)
- Xu-dong Jiao
- Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, PR China
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23
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Wang X, Wang Q, Xiao J, Liu Q, Wu H, Xu L, Zhang Y. Edwardsiella tarda T6SS component evpP is regulated by esrB and iron, and plays essential roles in the invasion of fish. FISH & SHELLFISH IMMUNOLOGY 2009; 27:469-477. [PMID: 19563898 DOI: 10.1016/j.fsi.2009.06.013] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 06/09/2009] [Accepted: 06/21/2009] [Indexed: 05/28/2023]
Abstract
Edwardsiella tarda is a gram-negative pathogen for hemorrhagic septicemia in a broad range of hosts. The type VI secretion system (T6SS) has recently been dissected in E. tarda to secrete EvpC, EvpI and a novel effector protein EvpP. In this study, sequencing and genetic alignments showed that evpP genes from different E. tarda isolates were highly similar and an evpP homolog was also found in Aeromonas hydrophila 0865 isolated from a diseased eel, suggesting the possible lateral gene transfer of evpP or the whole T6SS gene island. With reporter strains carrying gfp gene fused to the evpP promoter region, flow cytometric analysis revealed that transcription of evpP was positively regulated by either the two-component system EsrA-EsrB in E. tarda or the iron concentration in media. Compared with the parental strain, in-frame deletion of evpP in E. tarda EIB202 led to the significantly increased 50% lethal doses in zebrafish (Danio rerio) and Japanese flounder (Paralichthys olivaceus), decreased hemolytic activities, failure to adhere to mucus and reduced serum resistance, and complementation of an intact evpP gene restored these phenotypes in the evpP mutant. Investigation of infection kinetics indicated that the evpP deletion mutant was unable to proliferate in vivo, particularly in immune organs of fish. Moreover, the evpP deletion mutant exhibited incapacity to internalize in EPC cell model in vitro, demonstrating that EvpP in T6SS plays critical roles for invasion mechanism of E. tarda and merits as potential target for attenuated live vaccine construction.
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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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24
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Molecular analysis of the copper-responsive CopRSCD of a pathogenic Pseudomonas fluorescens strain. J Microbiol 2009; 47:277-86. [DOI: 10.1007/s12275-008-0278-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Accepted: 02/24/2009] [Indexed: 10/20/2022]
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25
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Wang HR, Hu YH, Zhang WW, Sun L. Construction of an attenuated Pseudomonas fluorescens strain and evaluation of its potential as a cross-protective vaccine. Vaccine 2009; 27:4047-55. [DOI: 10.1016/j.vaccine.2009.04.023] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 04/03/2009] [Accepted: 04/06/2009] [Indexed: 01/09/2023]
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Vitale S, Fauquant C, Lascoux D, Schauer K, Saint-Pierre C, Michaud-Soret I. A ZnS4 Structural Zinc Site in the Helicobacter pylori Ferric Uptake Regulator. Biochemistry 2009; 48:5582-91. [DOI: 10.1021/bi9004396] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Sylvia Vitale
- CNRS UMR 5249 Laboratoire de Chimie et Biologie des Métaux, Commissariat à l’Energie Atomique (CEA), Direction des Sciences du Vivant (DSV), l’Institut de Recherches en Technologies et Sciences pour le Vivant (iRTSV), and Université Joseph Fourier, 17 rue des Martyrs, F-38054 Grenoble Cedex 9, France
| | - Caroline Fauquant
- CNRS UMR 5249 Laboratoire de Chimie et Biologie des Métaux, Commissariat à l’Energie Atomique (CEA), Direction des Sciences du Vivant (DSV), l’Institut de Recherches en Technologies et Sciences pour le Vivant (iRTSV), and Université Joseph Fourier, 17 rue des Martyrs, F-38054 Grenoble Cedex 9, France
| | - David Lascoux
- Laboratoire de Spectrométrie de Masse des Protéines, Institut de Biologie Structurale, Jean-Pierre Ebel (UMR 5075 CNRS/CEA/UJF), F-38027 Grenoble Cedex 1, France
| | - Kristine Schauer
- Unité Pathogenèse de Helicobacter, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Christine Saint-Pierre
- Laboratoire des Lésions des Acides Nucléiques, DSM/INAC/Service de Chimie Inorganique et Biologique, UMR E-3 CEA/UJF CNRS FRE 3200, 17 rue des Martyrs, Grenoble F-38054 Cedex 9, France
| | - Isabelle Michaud-Soret
- CNRS UMR 5249 Laboratoire de Chimie et Biologie des Métaux, Commissariat à l’Energie Atomique (CEA), Direction des Sciences du Vivant (DSV), l’Institut de Recherches en Technologies et Sciences pour le Vivant (iRTSV), and Université Joseph Fourier, 17 rue des Martyrs, F-38054 Grenoble Cedex 9, France
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Attenuation of Edwardsiella tarda virulence by small peptides that interfere with LuxS/autoinducer type 2 quorum sensing. Appl Environ Microbiol 2009; 75:3882-90. [PMID: 19411415 DOI: 10.1128/aem.02690-08] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Edwardsiella tarda is a gram-negative pathogen with a broad host range that includes humans, animals, and fish. Recent studies have shown that the LuxS/autoinducer type 2 (AI-2) quorum sensing system is involved in the virulence of E. tarda. In the present study, it was found that the E. tarda LuxS mutants bearing deletions of the catalytic site (C site) and the tyrosine kinase phosphorylation site, respectively, are functionally inactive and that these dysfunctional mutants can interfere with the activity of the wild-type LuxS. Two small peptides, 5411 and 5906, which share sequence identities with the C site of LuxS, were identified. 5411 and 5906 proved to be inhibitors of AI-2 activity and could vitiate the infectivity of the pathogenic E. tarda strain TX1. The inhibitory effect of 5411 and 5906 on AI-2 activity is exerted on LuxS, with which these peptides specifically interact. The expression of 5411 and 5906 in TX1 has multiple effects (altering biofilm production and the expression of certain virulence-associated genes), which are similar to those caused by interruption of luxS expression. Further study found that it is very likely that 5411 and 5906 can be released from the strains expressing them and, should TX1 be in the vicinity, captured by TX1. Based on this observation, a constitutive 5411 producer (Pseudomonas sp. strain FP3/pT5411) was constructed in the form of a fish commensal isolate that expresses 5411 from a plasmid source. The presence of FP3/pT5411 in fish attenuates the virulence of TX1. Finally, it was demonstrated that fish expressing 5411 directly from tissues exhibit enhanced resistance against TX1 infection.
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28
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This is not your mother's repressor: the complex role of fur in pathogenesis. Infect Immun 2009; 77:2590-601. [PMID: 19364842 DOI: 10.1128/iai.00116-09] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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29
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Sun K, Cheng S, Zhang M, Wang F, Sun L. Cys-92, Cys-95, and the C-terminal 12 residues of the Vibrio harveyi ferric uptake regulator (Fur) are functionally inessential. J Microbiol 2008; 46:670-80. [PMID: 19107396 DOI: 10.1007/s12275-008-0113-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Accepted: 08/21/2008] [Indexed: 11/24/2022]
Abstract
Ferric uptake regulator (Fur) is a global regulator involved in multiple aspects of bacterial life. The gene encoding the Vibrio harveyi Fur (FurVh) was cloned from a pathogenic V. harveyi strain isolated from diseased fish. FurVh shares 77% overall sequence identity with the Escherichia coli Fur (FurEc) and could complement a mutant of FurEc. Like FurEc, FurVh, possesses two cysteine residues at positions 92 and 95, yet unlike FurEc, in which these cysteine residues constitute part of the metal ion coordination site and hence are vital to the repressor activity, C92 and C95 of FurVh proved to be functionally inessential. Further study identified a Vibrio Fur signature sequence, which is preserved in all the ten Vibrio Fur proteins that have been discovered to date but in none of the non-vibrio Fur proteins. Site-directed and random mutation analyses of the signature residues, the cysteine residues, and seven highly charged amino acid residues indicated that D9, H32, C137, and K138 of FurVh are functionally important but D9, C137, and K138 can be replaced by more than one functional substitutes. Systematic deletion analysis demonstrated that the C-terminal 12 residues of FurVh are functionally inessential. These results (i) indicated that the activation mechanism, or certain aspects of which, of FurVh is possibly different from that of FurEc; and (ii) suggested that it is not very likely that the C-terminal 12 residues play any significant role in the activation or stability of FurVh; and (iii) provided insights into the potential function of the local structure involving C137 and K138.
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Affiliation(s)
- Kun Sun
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, P. R. China
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