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Sheydai F, Tukmechi A. Cell wall disruption, membrane damage, and decrease in the expression of Yrp1 virulence factor in Yersinia ruckeri by propolis ethanol extract. IRANIAN JOURNAL OF MICROBIOLOGY 2023; 15:533-540. [PMID: 38045706 PMCID: PMC10692965 DOI: 10.18502/ijm.v15i4.13507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Background and Objectives Instead of antibiotics, propolis is a promising alternative for treating bacterial diseases. The aim of this study was to evaluate the effect of propolis ethanol extract (PEE) on Yersinia ruckeri (Y. ruckeri), a fish pathogen, by examining its impact on the cell wall, cytoplasmic membrane, and gene expression. Materials and Methods The effect of propolis on the bacterial cell wall, membrane, and DNA using scanning electron microscopy (SEM) was investigated. Its effect on the NAD+/NADH ratio, reactive oxygen species (ROS) production, as well as the expression of a virulence factor (yrp1) was also determined. Results It was demonstrated that PEE has multiple antibacterial mechanisms against Y. ruckeri involving cell wall damage, membrane lysis, and a decrease in gene expression. Conclusion The obtained results indicated that the mode of propolis action against Y. ruckeri is both structural and functional, while others showed propolis only could inactivate bacteria in a structural way.
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Affiliation(s)
- Fardin Sheydai
- Department of Microbiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran
| | - Amir Tukmechi
- Department of Microbiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran
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Yi X, Chen Y, Cai H, Wang J, Zhang Y, Zhu Z, Lin M, Qin Y, Jiang X, Xu X. The temperature-dependent expression of type II secretion system controls extracellular product secretion and virulence in mesophilic Aeromonas salmonida SRW-OG1. Front Cell Infect Microbiol 2022; 12:945000. [PMID: 35979091 PMCID: PMC9376225 DOI: 10.3389/fcimb.2022.945000] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 07/05/2022] [Indexed: 11/30/2022] Open
Abstract
Aeromonas salmonicida is a typical cold water bacterial pathogen that causes furunculosis in many freshwater and marine fish species worldwide. In our previous study, the pathogenic A. salmonicida (SRW-OG1) was isolated from a warm water fish, Epinephelus coioides was genomics and transcriptomics analyzed. Type II secretion system was found in the genome of A. salmonicida SRW-OG1, while the expressions of tatA, tatB, and tatC were significantly affected by temperature stress. Also, sequence alignment analysis, homology analysis and protein secondary structure function analysis showed that tatA, tatB, and tatC were highly conservative, indicating their biological significance. In this study, by constructing the mutants of tatA, tatB, and tatC, we investigated the mechanisms underlying temperature-dependent virulence regulation in mesophilic A. salmonida SRW-OG1. According to our results, tatA, tatB, and tatC mutants presented a distinct reduction in adhesion, hemolysis, biofilm formation and motility. Compared to wild-type strain, inhibition of the expression of tatA, tatB, and tatC resulted in a decrease in biofilm formation by about 23.66%, 19.63% and 40.13%, and a decrease in adhesion ability by approximately 77.69%, 80.41% and 62.14% compared with that of the wild-type strain. Furthermore, tatA, tatB, and tatC mutants also showed evidently reduced extracellular enzymatic activities, including amylase, protease, lipase, hemolysis and lecithinase. The genes affecting amylase, protease, lipase, hemolysis, and lecithinase of A. salmonicida SRW-OG1 were identified as cyoE, ahhh1, lipA, lipB, pulA, HED66_RS01350, HED66_RS19960, aspA, fabD, and gpsA, which were notably affected by temperature stress and mutant of tatA, tatB, and tatC. All above, tatA, tatB and tatC regulate the virulence of A. salmonicida SRW-OG1 by affecting biofilm formation, adhesion, and enzymatic activity of extracellular products, and are simultaneously engaged in temperature-dependent pathogenicity.
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Affiliation(s)
- Xin Yi
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, Engineering Research Center of the Modern Technology for Eel Industry, Jimei University, Xiamen, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen, China
| | - Yunong Chen
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, Engineering Research Center of the Modern Technology for Eel Industry, Jimei University, Xiamen, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen, China
| | - Hongyan Cai
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, Engineering Research Center of the Modern Technology for Eel Industry, Jimei University, Xiamen, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen, China
| | - Jiajia Wang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, Engineering Research Center of the Modern Technology for Eel Industry, Jimei University, Xiamen, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen, China
| | - Youyu Zhang
- Institute of Electromagnetics and Acoustics, School of Electronic Science and Engineering, Xiamen University, Xiamen, China
- *Correspondence: Xiaojin Xu, ; Youyu Zhang,
| | - ZhiQin Zhu
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, Engineering Research Center of the Modern Technology for Eel Industry, Jimei University, Xiamen, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen, China
| | - Mao Lin
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, Engineering Research Center of the Modern Technology for Eel Industry, Jimei University, Xiamen, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen, China
| | - Yingxue Qin
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, Engineering Research Center of the Modern Technology for Eel Industry, Jimei University, Xiamen, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen, China
| | - XingLong Jiang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, Engineering Research Center of the Modern Technology for Eel Industry, Jimei University, Xiamen, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen, China
| | - Xiaojin Xu
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, Engineering Research Center of the Modern Technology for Eel Industry, Jimei University, Xiamen, China
- Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen, China
- *Correspondence: Xiaojin Xu, ; Youyu Zhang,
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Banihashemi EA, Soltanian S, Gholamhosseini A, Banaee M. Effect of microplastics on Yersinia ruckeri infection in rainbow trout (Oncorhynchus mykiss). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:11939-11950. [PMID: 34554400 DOI: 10.1007/s11356-021-16517-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
Exposure to microorganisms such as Yersinia ruckeri can significantly affect bacterial infections in fish. Microplastics (MPs) may predispose fish to infection and act as carriers in pathogen transmission. Therefore, this study is designed to evaluate MPs' effect on damage caused by exposure to Y. ruckeri in rainbow trout. In this study, blood biochemical parameters and hepatic oxidative biomarkers as clinical signs were measured in the fish co-exposed to Y. ruckeri (5 and 10% the median lethal dose (LD50)) and MPs (500 and 1000 mg Kg-1) for 30 days. There were no significant changes in the creatinine, triglyceride, cholesterol levels, and glutamic-pyruvic transaminase activity in the blood of fish infected with Y. ruckeri. In contrast, exposure to MPs had a significant effect on most clinical parameters. The total protein, albumin, globulin, total immunoglobulins, high-density lipoprotein, low-density lipoprotein, cholesterol levels, and γ-glutamyltransferase activity decreased, whereas glucose, triglyceride, and creatinine levels, and glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase, alkaline phosphatase, and lactate dehydrogenase activities increased in the plasma of fish after co-exposure to MPs and Y. ruckeri. Dietary MPs combined with a Y. ruckeri challenge decreased catalase and glutathione peroxidase activities, and total antioxidant levels. However, superoxide dismutase activity and malondialdehyde contents increased in the hepatocyte of fish co-exposed to MPs and Y. ruckeri. This study suggests that fish exposure to MPs and simultaneous challenge with Y. ruckeri could synergistically affect clinical parameters.
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Affiliation(s)
- Elham Alsadat Banihashemi
- Division of Aquatic Animal Health & Diseases, Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Siyavash Soltanian
- Division of Aquatic Animal Health & Diseases, Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran.
| | - Amin Gholamhosseini
- Division of Aquatic Animal Health & Diseases, Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran.
| | - Mahdi Banaee
- Aquaculture Department, Faculty of Natural Resources and the Environment, Behbahan Khatam Alanbia University of Technology, Behbahan, Iran
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Wrobel A, Leo JC, Linke D. Overcoming Fish Defences: The Virulence Factors of Yersinia ruckeri. Genes (Basel) 2019; 10:E700. [PMID: 31514317 PMCID: PMC6770984 DOI: 10.3390/genes10090700] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 09/02/2019] [Accepted: 09/05/2019] [Indexed: 12/24/2022] Open
Abstract
Yersinia ruckeri is the causative agent of enteric redmouth disease, a bacterial infection of marine and freshwater fish. The disease mainly affects salmonids, and outbreaks have significant economic impact on fish farms all over the world. Vaccination routines are in place against the major serotypes of Y. ruckeri but are not effective in all cases. Despite the economic importance of enteric redmouth disease, a detailed molecular understanding of the disease is lacking. A considerable number of mostly omics-based studies have been performed in recent years to identify genes related to Y. ruckeri virulence. This review summarizes the knowledge on Y. ruckeri virulence factors. Understanding the molecular pathogenicity of Y. ruckeri will aid in developing more efficient vaccines and antimicrobial compounds directed against enteric redmouth disease.
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Affiliation(s)
- Agnieszka Wrobel
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
| | - Jack C Leo
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
- Department of Biosciences, School of Science and Technology, Nottingham Trent University, Nottingham NG1 4FQ, UK.
| | - Dirk Linke
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
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Guijarro JA, García-Torrico AI, Cascales D, Méndez J. The Infection Process of Yersinia ruckeri: Reviewing the Pieces of the Jigsaw Puzzle. Front Cell Infect Microbiol 2018; 8:218. [PMID: 29998086 PMCID: PMC6028603 DOI: 10.3389/fcimb.2018.00218] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 06/08/2018] [Indexed: 12/20/2022] Open
Abstract
Finding the keys to understanding the infectious process of Yersinia ruckeri was not a priority for many years due to the prompt development of an effective biotype 1 vaccine which was used mainly in Europe and USA. However, the gradual emergence of outbreaks in vaccinated fish, which have been reported since 2003, has awakened interest in the mechanism of virulence in this pathogen. Thus, during the last two decades, a large number of studies have considerably enriched our knowledge of many aspects of the pathogen and its interaction with the host. By means of both conventional and a variety of novel strategies, such as cell GFP tagging, bioluminescence imaging and optical projection tomography, it has been possible to determine three putative Y. ruckeri infection routes, the main point of entry for the bacterium being the gill lamellae. Moreover, a wide range of potential virulence factors have been highlighted by specific gene mutagenesis strategies or genome-wide transposon/plasmid insertion-based screening approaches, such us in vivo expression technology (IVET) and signature tagged mutagenesis (STM). Finally, recent proteomic and whole genomic analyses have allowed many of the genes and systems that are potentially implicated in the organism's pathogenicity and its adaptation to the host environmental conditions to be elucidated. Altogether, these studies contribute to a better understanding of the infectious process of Y. ruckeri in fish, which is crucial for the development of more effective strategies for preventing or treating enteric redmouth disease (ERM).
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Affiliation(s)
- José A Guijarro
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias (IUBA), Universidad de Oviedo, Oviedo, Spain
| | - Ana I García-Torrico
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias (IUBA), Universidad de Oviedo, Oviedo, Spain
| | - Desirée Cascales
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias (IUBA), Universidad de Oviedo, Oviedo, Spain
| | - Jessica Méndez
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias (IUBA), Universidad de Oviedo, Oviedo, Spain
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Mendez J, Cascales D, Garcia-Torrico AI, Guijarro JA. Temperature-Dependent Gene Expression in Yersinia ruckeri: Tracking Specific Genes by Bioluminescence During in Vivo Colonization. Front Microbiol 2018; 9:1098. [PMID: 29887855 PMCID: PMC5981175 DOI: 10.3389/fmicb.2018.01098] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 05/08/2018] [Indexed: 11/26/2022] Open
Abstract
Yersinia ruckeri is a bacterium causing fish infection processes at temperatures below the optimum for growth. A derivative Tn5 transposon was used to construct a library of Y. ruckeri mutants with transcriptional fusions between the interrupted genes and the promoterless luxCDABE and lacZY operons. In vitro analysis of β-galactosidase activity allowed the identification of 168 clones having higher expression at 18°C than at 28°C. Among the interrupted genes a SAM-dependent methyltransferase, a diguanylated cyclase, three genes involved in legionaminic acid synthesis and three transcriptional regulators were defined. In order to determine, via bioluminescence emission, the in vivo expression of some of these genes, two of the selected mutants were studied. In one of them, the acrR gene coding a repressor involved in regulation of the AcrAB-TolC expulsion pump was interrupted. This mutant was found to be highly resistant to compounds such as chloramphenicol, tetracycline, and ciprofloxacin. Although acrR mutation was not related to virulence in Y. ruckeri, this mutant was useful to analyze acrR expression in fish tissues in vivo. The other gene studied was osmY which is activated under osmotic stress and is involved in virulence. In this case, complemented mutant was used for experiments with fish. In vivo analysis of bioluminescence emission by these two strains showed higher values for acrR in gut, liver and adipose tissue, whereas osmY showed higher luminescence in gut and, at the end of the infection process, in muscle tissue. Similar results were obtained in ex vivo assays using rainbow trout tissues. The results indicated that this kind of approach was useful for the identification of genes related to virulence in Y. ruckeri and also for the in vivo and in vitro studies of each of the selected genes.
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Affiliation(s)
- Jessica Mendez
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias, Universidad de Oviedo, Oviedo, Spain
| | - Desirée Cascales
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias, Universidad de Oviedo, Oviedo, Spain
| | - Ana I Garcia-Torrico
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias, Universidad de Oviedo, Oviedo, Spain
| | - Jose A Guijarro
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias, Universidad de Oviedo, Oviedo, Spain
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Munang'andu HM. Intracellular Bacterial Infections: A Challenge for Developing Cellular Mediated Immunity Vaccines for Farmed Fish. Microorganisms 2018; 6:microorganisms6020033. [PMID: 29690563 PMCID: PMC6027125 DOI: 10.3390/microorganisms6020033] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 04/15/2018] [Accepted: 04/20/2018] [Indexed: 12/15/2022] Open
Abstract
Aquaculture is one of the most rapidly expanding farming systems in the world. Its rapid expansion has brought with it several pathogens infecting different fish species. As a result, there has been a corresponding expansion in vaccine development to cope with the increasing number of infectious diseases in aquaculture. The success of vaccine development for bacterial diseases in aquaculture is largely attributed to empirical vaccine designs based on inactivation of whole cell (WCI) bacteria vaccines. However, an upcoming challenge in vaccine design is the increase of intracellular bacterial pathogens that are not responsive to WCI vaccines. Intracellular bacterial vaccines evoke cellular mediated immune (CMI) responses that “kill” and eliminate infected cells, unlike WCI vaccines that induce humoral immune responses whose protective mechanism is neutralization of extracellular replicating pathogens by antibodies. In this synopsis, I provide an overview of the intracellular bacterial pathogens infecting different fish species in aquaculture, outlining their mechanisms of invasion, replication, and survival intracellularly based on existing data. I also bring into perspective the current state of CMI understanding in fish together with its potential application in vaccine development. Further, I highlight the immunological pitfalls that have derailed our ability to produce protective vaccines against intracellular pathogens for finfish. Overall, the synopsis put forth herein advocates for a shift in vaccine design to include CMI-based vaccines against intracellular pathogens currently adversely affecting the aquaculture industry.
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Affiliation(s)
- Hetron Mweemba Munang'andu
- Section of Aquatic Medicine and Nutrition, Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Ullevålsveien 72, P.O. Box 8146, Dep NO-0033, 046 Oslo, Norway.
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Strøm HK, Ohtani M, Nowak B, Boutrup TS, Jones B, Raida MK, Bojesen AM. Experimental infection by Yersinia ruckeri O1 biotype 2 induces brain lesions and neurological signs in rainbow trout (Oncorhynchus mykiss). JOURNAL OF FISH DISEASES 2018; 41:529-537. [PMID: 29148587 DOI: 10.1111/jfd.12754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 10/04/2017] [Accepted: 10/08/2017] [Indexed: 06/07/2023]
Abstract
Pathological manifestations in rainbow trout (Oncorhynchus mykiss) following experimental waterborne infection with Yersinia ruckeri serotype O1 biotype 2 (strain 07111224) were investigated. Rainbow trout were exposed to 8 × 107 CFU/ml of Y. ruckeri by bath for 6 hr, and mortality was then monitored for 22 days post-infection (dpi). Organs were sampled at 3 dpi and also from moribund fish showing signs of severe systemic infection such as bleeding, exophthalmia or erratic swimming behaviour. Y. ruckeri was observed in the meninges and diencephalon of the brain, and lamina propria of olfactory organ at 3 dpi. At 12 dpi, Y. ruckeri had spread throughout the brain including cranial connective tissues and ventricles and the infection was associated with haemorrhages and an infiltration with leucocytes. Y. ruckeri infection and associated with leucocyte infiltration were observed at 13 dpi. In conclusion, Y. ruckeri strain 07111224 causes encephalitis in the acute phase of infection, which could explain why Y. ruckeri-affected fish show exophthalmia and erratic swimming known as signs of ERM.
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Affiliation(s)
- H K Strøm
- Section of Veterinary Clinical Microbiology, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - M Ohtani
- Section of Veterinary Clinical Microbiology, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - B Nowak
- Institute for Marine and Antarctic Studies, University of Tasmania, Launceston, Tas., Australia
- Department of Bioscience, Arctic Research Centre, Aarhus University, Aarhus, Denmark
| | - T S Boutrup
- Aquapri Denmark A/S, Frederiksvaerk, Denmark
| | - B Jones
- Murdoch University School of Veterinary and Life Sciences, Perth, WA, Australia
| | | | - A M Bojesen
- Section of Veterinary Clinical Microbiology, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
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Pérez-Pascual D, Rochat T, Kerouault B, Gómez E, Neulat-Ripoll F, Henry C, Quillet E, Guijarro JA, Bernardet JF, Duchaud E. More Than Gliding: Involvement of GldD and GldG in the Virulence of Flavobacterium psychrophilum. Front Microbiol 2017; 8:2168. [PMID: 29163446 PMCID: PMC5682007 DOI: 10.3389/fmicb.2017.02168] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 10/23/2017] [Indexed: 12/17/2022] Open
Abstract
A fascinating characteristic of most members of the genus Flavobacterium is their ability to move over surfaces by gliding motility. Flavobacterium psychrophilum, an important pathogen of farmed salmonids worldwide, contains in its genome the 19 gld and spr genes shown to be required for gliding or spreading in Flavobacterium johnsoniae; however, their relative role in its lifestyle remains unknown. In order to address this issue, two spreading deficient mutants were produced as part of a Tn4351 mutant library in F. psychrophilum strain THCO2-90. The transposons were inserted in gldD and gldG genes. While the wild-type strain is proficient in adhesion, biofilm formation and displays strong proteolytic activity, both mutants lost these characteristics. Extracellular proteome comparisons revealed important modifications for both mutants, with a significant reduction of the amounts of proteins likely transported through the outer membrane by the Type IX secretion system, indicating that GldD and GldG proteins are required for an effective activity of this system. In addition, a significant decrease in virulence was observed using rainbow trout bath and injection infection models. Our results reveal additional roles of gldD and gldG genes that are likely of importance for the F. psychrophilum lifestyle, including virulence.
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Affiliation(s)
- David Pérez-Pascual
- Virologie et Immunologie Moléculaires, Institut National de la Recherche Agronomique, Université Paris-Saclay, Jouy-en-Josas, France
| | - Tatiana Rochat
- Virologie et Immunologie Moléculaires, Institut National de la Recherche Agronomique, Université Paris-Saclay, Jouy-en-Josas, France
| | - Brigitte Kerouault
- Virologie et Immunologie Moléculaires, Institut National de la Recherche Agronomique, Université Paris-Saclay, Jouy-en-Josas, France
| | - Esther Gómez
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias (IUBA), Universidad de Oviedo, Oviedo, Spain
| | - Fabienne Neulat-Ripoll
- Virologie et Immunologie Moléculaires, Institut National de la Recherche Agronomique, Université Paris-Saclay, Jouy-en-Josas, France
| | - Celine Henry
- PAPPSO, Micalis Institute, Institut National de la Recherche Agronomique, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Edwige Quillet
- GABI, Institut National de la Recherche Agronomique, Université Paris-Saclay, Jouy-en-Josas, France
| | - Jose A Guijarro
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias (IUBA), Universidad de Oviedo, Oviedo, Spain
| | - Jean F Bernardet
- Virologie et Immunologie Moléculaires, Institut National de la Recherche Agronomique, Université Paris-Saclay, Jouy-en-Josas, France
| | - Eric Duchaud
- Virologie et Immunologie Moléculaires, Institut National de la Recherche Agronomique, Université Paris-Saclay, Jouy-en-Josas, France
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Kumar G, Hummel K, Welch TJ, Razzazi-Fazeli E, El-Matbouli M. Global proteomic profiling of Yersinia ruckeri strains. Vet Res 2017; 48:55. [PMID: 28931430 PMCID: PMC5607619 DOI: 10.1186/s13567-017-0460-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 09/06/2017] [Indexed: 11/10/2022] Open
Abstract
Yersinia ruckeri is the causative agent of enteric redmouth disease (ERM) of salmonids. There is little information regarding the proteomics of Y. ruckeri. Herein, we perform whole protein identification and quantification of biotype 1 and biotype 2 strains of Y. ruckeri grown under standard culture conditions using a shotgun proteomic approach. Proteins were extracted, digested and peptides were separated by a nano liquid chromatography system and analyzed with a high-resolution hybrid triple quadrupole time of flight mass spectrometer coupled via a nano ESI interface. SWATH-MS technology and sophisticated statistical analyses were used to identify proteome differences among virulent and avirulent strains. GO annotation, subcellular localization, virulence proteins and antibiotic resistance ontology were predicted using bioinformatic tools. A total of 1395 proteins were identified in the whole cell of Y. ruckeri. These included proteases, chaperones, cell division proteins, outer membrane proteins, lipoproteins, receptors, ion binding proteins, transporters and catalytic proteins. In virulent strains, a total of 16 proteins were upregulated including anti-sigma regulatory factor, arginine deiminase, phosphate-binding protein PstS and superoxide dismutase Cu-Zu. Additionally, several virulence proteins were predicted such as Clp and Lon pro-teases, TolB, PPIases, PstS, PhoP and LuxR family transcriptional regulators. These putative virulence proteins might be used for development of novel targets for treatment of ERM in fish. Our study represents one of the first global proteomic reference profiles of Y. ruckeri and this data can be accessed via ProteomeXchange with identifier PXD005439. These proteomic profiles elucidate proteomic mechanisms, pathogenicity, host-interactions, antibiotic resistance ontology and localization of Y. ruckeri proteins.
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Affiliation(s)
- Gokhlesh Kumar
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria.
| | - Karin Hummel
- VetCore Facility for Research/Proteomics Unit, University of Veterinary Medicine, Vienna, Austria
| | - Timothy J Welch
- National Center for Cool and Cold Water Aquaculture, Kearneysville, USA
| | - Ebrahim Razzazi-Fazeli
- VetCore Facility for Research/Proteomics Unit, University of Veterinary Medicine, Vienna, Austria
| | - Mansour El-Matbouli
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria
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Kumar G, Menanteau-Ledouble S, Saleh M, El-Matbouli M. Yersinia ruckeri, the causative agent of enteric redmouth disease in fish. Vet Res 2015; 46:103. [PMID: 26404907 PMCID: PMC4581093 DOI: 10.1186/s13567-015-0238-4] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 08/11/2015] [Indexed: 11/30/2022] Open
Abstract
Enteric redmouth disease (ERM) is a serious septicemic bacterial disease of salmonid fish species. It is caused by Yersinia ruckeri, a Gram-negative rod-shaped enterobacterium. It has a wide host range, broad geographical distribution, and causes significant economic losses in the fish aquaculture industry. The disease gets its name from the subcutaneous hemorrhages, it can cause at the corners of the mouth and in gums and tongue. Other clinical signs include exophthalmia, darkening of the skin, splenomegaly and inflammation of the lower intestine with accumulation of thick yellow fluid. The bacterium enters the fish via the secondary gill lamellae and from there it spreads to the blood and internal organs. Y. ruckeri can be detected by conventional biochemical, serological and molecular methods. Its genome is 3.7 Mb with 3406–3530 coding sequences. Several important virulence factors of Y. ruckeri have been discovered, including haemolyin YhlA and metalloprotease Yrp1. Both non-specific and specific immune responses of fish during the course of Y. ruckeri infection have been well characterized. Several methods of vaccination have been developed for controlling both biotype 1 and biotype 2 Y. ruckeri strains in fish. This review summarizes the current state of knowledge regarding enteric redmouth disease and Y. ruckeri: diagnosis, genome, virulence factors, interaction with the host immune responses, and the development of vaccines against this pathogen.
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Affiliation(s)
- Gokhlesh Kumar
- Clinical Division of Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna, Austria.
| | - Simon Menanteau-Ledouble
- Clinical Division of Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna, Austria.
| | - Mona Saleh
- Clinical Division of Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna, Austria.
| | - Mansour El-Matbouli
- Clinical Division of Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna, Austria.
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Guijarro JA, Cascales D, García-Torrico AI, García-Domínguez M, Méndez J. Temperature-dependent expression of virulence genes in fish-pathogenic bacteria. Front Microbiol 2015. [PMID: 26217329 PMCID: PMC4496569 DOI: 10.3389/fmicb.2015.00700] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Virulence gene expression in pathogenic bacteria is modulated by environmental parameters. A key factor in this expression is temperature. Its effect on virulence gene expression in bacteria infecting warm-blooded hosts is well documented. Transcription of virulence genes in these bacteria is induced upon a shift from low environmental to a higher host temperature (37°C). Interestingly, host temperatures usually correspond to the optimum for growth of these pathogenic bacteria. On the contrary, in ectothermic hosts such as fish, molluscs, and amphibians, infection processes generally occur at a temperature lower than that for the optimal growth of the bacteria. Therefore, regulation of virulence gene expression in response to temperature shift has to be modulated in a different way to that which is found in bacteria infecting warm-blooded hosts. The current understanding of virulence gene expression and its regulation in response to temperature in fish-pathogenic bacteria is limited, but constant extension of our knowledge base is essential to enable a rational approach to the problem of the bacterial fish diseases affecting the aquaculture industry. This is an interesting issue and progress needs to be made in order to diminish the economic losses caused by these diseases. The intention of this review is, for the first time, to compile the scattered results existing in the field in order to lay the groundwork for future research. This article is an overview of those relevant virulence genes that are expressed at temperatures lower than that for optimal bacterial growth in different fish-pathogenic bacteria as well as the principal mechanisms that could be involved in their regulation.
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Affiliation(s)
- José A. Guijarro
- *Correspondence: José A. Guijarro, Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias, Universidad de Oviedo, C/Julían Clavería 6, 33006 Oviedo, Spain,
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Méndez J, Guijarro JA. In vivo monitoring of Yersinia ruckeri in fish tissues: progression and virulence gene expression. ENVIRONMENTAL MICROBIOLOGY REPORTS 2013; 5:179-185. [PMID: 23757147 DOI: 10.1111/1758-2229.12030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 12/14/2012] [Accepted: 12/16/2012] [Indexed: 06/02/2023]
Abstract
In this study, the utilization of bioluminescence imaging (BLI) allowed us to define the progression of Yersinia ruckeri during the infection of rainbow trout. A luminescent Y. ruckeri 150 strain was engineered using the pCS26-Pac plasmid containing the lux operon from Photorhabdus luminescens. Two different models of infection of rainbow trout were defined depending on the route in which bacteria were administered, being the gut the major organ affected following bath immersion. This indicates that this organ is important for bacterial dissemination inside the fish and the establishment of the infection. Moreover, the expression of three previously selected operons by in vivo expression technology (IVET) was analysed, the yhlBA involved in the production of a haemolysin, the cdsAB related to the uptake of cysteine and the yctCBA implicated in citrate uptake. Apart from these factors, the expression of yrp1 encoding a serralysin metalloprotease involved in pathogenesis was also analysed. The results indicated that all of the assayed promoters were expressed during infection of rainbow trout. In addition to these findings, the methodology described in this work constitutes a useful model for studying the infection process in other fish pathogenic bacteria.
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Affiliation(s)
- J Méndez
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, IUBA, Universidad de Oviedo, 33006 Oviedo, Asturias, Spain
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Chistyulin DK, Novikova OD, Portnyagina OY, Khomenko VA, Vakorina TI, Kim NY, Isaeva MP, Likhatskaya GN, Solov’eva TF. Isolation and characterization of OmpF-like porin from Yersinia ruckeri. BIOCHEMISTRY MOSCOW SUPPLEMENT SERIES A-MEMBRANE AND CELL BIOLOGY 2012. [DOI: 10.1134/s1990747812030038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Pérez-Pascual D, Gómez E, Álvarez B, Méndez J, Reimundo P, Navais R, Duchaud E, Guijarro JA. Comparative analysis and mutation effects of fpp2-fpp1 tandem genes encoding proteolytic extracellular enzymes of Flavobacterium psychrophilum. MICROBIOLOGY-SGM 2011; 157:1196-1204. [PMID: 21292745 DOI: 10.1099/mic.0.046938-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Flavobacterium psychrophilum is a very significant fish pathogen that secretes two biochemically characterized extracellular proteolytic enzymes, Fpp1 and Fpp2. The genes encoding these enzymes are organized as an fpp2-fpp1 tandem in the genome of strain F. psychrophilum THC02/90. Analysis of the corresponding encoded proteins showed that they belong to two different protease families. For gene function analysis, new genetic tools were developed in F. psychrophilum by constructing stable isogenic fpp1 and fpp2 mutants via single-crossover homologous recombination. RT-PCR analysis of wild-type and mutant strains suggested that both genes are transcribed as a single mRNA from the promoter located upstream of the fpp2 gene. Phenotypic characterization of the fpp2 mutant showed lack of caseinolytic activity and higher colony spreading compared with the wild-type strain. Both characteristics were recovered in the complemented strain. One objective of this work was to assess the contribution to virulence of these proteolytic enzymes. LD(50) experiments using the wild-type strain and mutants showed no significant differences in virulence in a rainbow trout challenge model, suggesting instead a possible nutritional role. The gene disruption procedure developed in this work, together with the knowledge of the complete genome sequence of F. psychrophilum, open new perspectives for the study of gene function in this bacterium.
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Affiliation(s)
- David Pérez-Pascual
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, IUBA, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Esther Gómez
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, IUBA, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Beatriz Álvarez
- Karolinska Institutet, Institutionen för Laboratoriemedicin, Karolinska Universitetssjukhuset, 14186 Stockholm, Sweden
| | - Jessica Méndez
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, IUBA, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Pilar Reimundo
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, IUBA, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Roberto Navais
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, IUBA, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Eric Duchaud
- Unité de Virologie et Immunologie Moléculaires, Equipe Infection et Immunité des Poissons, INRA-Domaine de Vilvert, 78352 Jouy en Josas Cédex, France
| | - José A Guijarro
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, IUBA, Universidad de Oviedo, 33006 Oviedo, Spain
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Raida MK, Buchmann K. Bath vaccination of rainbow trout (Oncorhynchus mykiss Walbaum) against Yersinia ruckeri: effects of temperature on protection and gene expression. Vaccine 2008; 26:1050-62. [PMID: 18237828 DOI: 10.1016/j.vaccine.2007.12.029] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Revised: 12/11/2007] [Accepted: 12/16/2007] [Indexed: 10/22/2022]
Abstract
Protection of rainbow trout fry following bath vaccination with a bacterin of Y. ruckeri O1, the bacterial pathogen causing enteric red mouth disease (ERM), was investigated at 5, 15 and 25 degrees C. Rainbow trout fry were acclimatised for 8 weeks at the three temperatures before vaccination. They were subsequently challenged with Y. ruckeri 4 and 8 weeks post-vaccination which demonstrated a significant protection of vaccinated fish kept at 15 degrees C. No protective effect of vaccination in rainbow trout reared at 5 and 25 degrees C could be recorded. Spleen tissue was sampled from vaccinated and control fish at 0, 8, 24 and 72 h post-vaccination in order to analyse gene transcript profiles using quantitative real-time RT-PCR (q-PCR). Gene expression in fish vaccinated at 15 degrees C (the protected fish) was up-regulated with regard to the pro-inflammatory cytokines IFN-gamma, TNF-alpha, IL-6 and the anti-inflammatory cytokines IL-10 and TGF-beta, the cell receptors TcR, CD8alpha, CD4, C5aR and the teleost specific immunoglobulin IgT. Passive immunisation using transfer of plasma from vaccinated fish to naïve fish conferred no protection. This indicates that humoral factors such as Ig and complement are less important in the protection induced by bath vaccination. Expression of cellular factors such as CD8alpha was significantly increased in the protected trout and this suggests that cellular factors including cytotoxic T-cells could play a role in immunity against Y. ruckeri.
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Affiliation(s)
- M K Raida
- Faculty of Life Sciences, Department of Veterinary Pathobiology, University of Copenhagen, Frederiksberg, Denmark.
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Fernández L, Méndez J, Guijarro JA. Molecular virulence mechanisms of the fish pathogen Yersinia ruckeri. Vet Microbiol 2007; 125:1-10. [PMID: 17651924 DOI: 10.1016/j.vetmic.2007.06.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2007] [Revised: 05/31/2007] [Accepted: 06/15/2007] [Indexed: 11/21/2022]
Abstract
Yersinia ruckeri is the causative agent of enteric redmouth disease or yersiniosis, which affects mainly salmonids. This microorganism has been consistently causing economic losses in the aquaculture industry since its first description; but the early development of a vaccine allowed a relative control of the disease. This might be the reason why the specific pathogenicity mechanisms of this bacterium remained elusive until recently, when the results obtained with traditional microbiology have been complemented with those provided by molecular biology. The data obtained by using these novel techniques, which are the main subject of this review, have started to shed light on the virulence of this pathogen. Thus, iron acquisition by the siderophore ruckerbactin, proteolytic and haemolytic activities, and resistance to immune mechanisms, were proved to be involved in the virulence of this bacterium. Additionally, these data will, in the long term, help clarify the controversial taxonomic status of this microorganism and allow the development of novel ways to prevent outbreaks, which is particularly interesting nowadays, given that commercial vaccines seem to be ineffective against some new isolates.
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Affiliation(s)
- Lucía Fernández
- Area de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, IUBA, Universidad de Oviedo, 33006 Oviedo, Asturias, Spain
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Tobback E, Decostere A, Hermans K, Haesebrouck F, Chiers K. Yersinia ruckeri infections in salmonid fish. JOURNAL OF FISH DISEASES 2007; 30:257-68. [PMID: 17501736 DOI: 10.1111/j.1365-2761.2007.00816.x] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Yersinia ruckeri is the causative agent of yersiniosis or enteric redmouth disease leading to significant economic losses in salmonid aquaculture worldwide. Infection may result in a septicaemic condition with haemorrhages on the body surface and in the internal organs. Despite the significance of the disease, very little information is available on the pathogenesis, hampering the development of preventive measures to efficiently combat this bacterial agent. This review discusses the agent and the disease it causes. The possibility of the presence of similar virulence markers and/or pathogenic mechanisms between the Yersinia species which elicit disease in humans and Y. ruckeri is also examined.
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Affiliation(s)
- E Tobback
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
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Fernández L, Prieto M, Guijarro JA. The iron- and temperature-regulated haemolysin YhlA is a virulence factor of Yersinia ruckeri. MICROBIOLOGY-SGM 2007; 153:483-489. [PMID: 17259619 DOI: 10.1099/mic.0.29284-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Yersinia ruckeri causes the enteric redmouth disease or yersiniosis, an important systemic fish infection. In an attempt to dissect the virulence mechanisms of this bacterium, a gene encoding a putative protein involved in the secretion/activation of a haemolysin (yhlB), which had been previously identified by in vivo expression technology, was further analysed. The gene yhlB precedes another ORF (yhlA) encoding a Serratia-type haemolysin. Other toxins belonging to this group have been identified in genomic analyses of human-pathogenic yersiniae, although their role and importance in pathogenicity have not been defined yet. In spite of its being an in vivo-induced gene, the expression of yhlA can be induced under certain in vitro conditions similar to those encountered in the host, as deduced from the results obtained by using a yhlB : : lacZY fusion. Thus, higher levels of expression were obtained at 18 degrees C, the temperature of occurrence of disease outbreaks, than at 28 degrees C, the optimal growth temperature. The expression of the haemolysin also increased under iron-starvation conditions. This confirmed the decisive role of iron and temperature as environmental cues that regulate and coordinate the expression of genes encoding extracellular factors involved in the virulence of Y. ruckeri. LD(50) and cell culture experiments, using yhlB and yhlA insertional mutant strains, demonstrated the participation of the haemolysin in the virulence of Y. ruckeri and also its cytolytic properties against the BF-2 fish cell line. Finally, a screening for the production of haemolytic activity and the presence of yhlB and yhlA genes in 12 Y. ruckeri strains proved once more the genetic homogeneity of this species, since all possessed both haemolytic activity and the yhlB and yhlA genes.
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Affiliation(s)
- Lucía Fernández
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, IUBA, Universidad de Oviedo, 33006 Oviedo, Asturias, Spain
| | - Miguel Prieto
- Laboratorio de Sanidad Animal de Jove, Serida, 33299 Gijón, Asturias, Spain
| | - José A Guijarro
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, IUBA, Universidad de Oviedo, 33006 Oviedo, Asturias, Spain
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Kastbjerg VG, Nielsen KF, Dalsgaard I, Rasch M, Bruhn JB, Givskov M, Gram L. Profiling acylated homoserine lactones in Yersinia ruckeri and influence of exogenous acyl homoserine lactones and known quorum-sensing inhibitors on protease production. J Appl Microbiol 2007; 102:363-74. [PMID: 17241341 DOI: 10.1111/j.1365-2672.2006.03109.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To profile the quorum-sensing (QS) signals in Yersinia ruckeri and to examine the possible regulatory link between QS signals and a typical QS-regulated virulence phenotype, a protease. METHODS AND RESULTS Liquid chromatography-high resolution mass spectrometry (HPLC-HRMS) showed that Y. ruckeri produced at least eight different acylated homoserine lactones (AHLs) with N-(3-oxooctanoyl)-L-homoserine lactone (3-oxo-C8-HSL) being the dominant molecule. Also, some uncommon AHL, N-(3-oxoheptanoyl)-L-homoserine lactone (3-oxo-C7-HSL) and N-(3-oxononanoyl)-L-homoserine lactone (3-oxo-C9-HSL), were produced. 3-oxo-C8-HSL was detected in organs from fish infected with Y. ruckeri. Protease production was significantly lower at temperatures above 23 degrees C than below although growth was faster at the higher temperatures. Neither addition of sterile filtered high-density Y. ruckeri culture supernatant nor the addition of pure exogenous AHLs induced protease production. Furthermore, three QS inhibitors (QSIs), sulfur-containing AHL analogues, did not inhibit protease production in Y. ruckeri. CONCLUSIONS Exogenous AHL or sulfur-containing AHL analogues did not influence the protease production indicating that protease production may not be QS regulated in Y. ruckeri. SIGNIFICANCE AND IMPACT OF THE STUDY The array of different AHLs produced indicates that the QS system of Y. ruckeri is complex and could involve several regulatory systems. In this case, neither AHLs nor QSI would be likely to directly affect a QS-regulated phenotype.
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Affiliation(s)
- V G Kastbjerg
- Department of Seafood Research, Danish Institute for Fisheries Research, Lyngby, Denmark.
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Fernández L, Márquez I, Guijarro JA. Identification of specific in vivo-induced (ivi) genes in Yersinia ruckeri and analysis of ruckerbactin, a catecholate siderophore iron acquisition system. Appl Environ Microbiol 2004; 70:5199-207. [PMID: 15345400 PMCID: PMC520893 DOI: 10.1128/aem.70.9.5199-5207.2004] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2004] [Accepted: 05/27/2004] [Indexed: 11/20/2022] Open
Abstract
This work reports the utilization of an in vivo expression technology system to identify in vivo-induced (ivi) genes in Yersinia ruckeri after determination of the conditions needed for its selection in fish. Fourteen clones were selected, and the cloned DNA fragments were analyzed after partial sequencing. In addition to sequences with no significant similarity, homology with genes encoding proteins putatively involved in two-component and type IV secretion systems, adherence, specific metabolic functions, and others were found. Among these sequences, four were involved in iron acquisition through a catechol siderophore (ruckerbactin). Thus, unlike other pathogenic yersiniae producing yersiniabactin, Y. ruckeri might be able to produce and utilize only this phenolate. The genetic organization of the ruckerbactin biosynthetic and uptake loci was similar to that of the Escherichia coli enterobactin gene cluster. Genes rucC and rupG, putative counterparts of E. coli entC and fepG, respectively, involved in the biosynthesis and transport of the iron siderophore complex, respectively, were analyzed further. Thus, regulation of expression by iron and temperature and their presence in other Y. ruckeri siderophore-producing strains were confirmed for these two loci. Moreover, 50% lethal dose values 100-fold higher than those of the wild-type strain were obtained with the rucC isogenic mutant, showing the importance of ruckerbactin in the pathogenesis caused by this microorganism.
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Affiliation(s)
- L Fernández
- Microbiologia, Facultad de Medicina, Universidad de Oviedo, 33006 Oviedo, Asturias, Spain.
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