1
|
Semple SL, Dixon B. Salmonid Antibacterial Immunity: An Aquaculture Perspective. BIOLOGY 2020; 9:E331. [PMID: 33050557 PMCID: PMC7599743 DOI: 10.3390/biology9100331] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/07/2020] [Accepted: 10/08/2020] [Indexed: 02/08/2023]
Abstract
The aquaculture industry is continuously threatened by infectious diseases, including those of bacterial origin. Regardless of the disease burden, aquaculture is already the main method for producing fish protein, having displaced capture fisheries. One attractive sector within this industry is the culture of salmonids, which are (a) uniquely under pressure due to overfishing and (b) the most valuable finfish per unit of weight. There are still knowledge gaps in the understanding of fish immunity, leading to vaccines that are not as effective as in terrestrial species, thus a common method to combat bacterial disease outbreaks is the use of antibiotics. Though effective, this method increases both the prevalence and risk of generating antibiotic-resistant bacteria. To facilitate vaccine design and/or alternative treatment efforts, a deeper understanding of the teleost immune system is essential. This review highlights the current state of teleost antibacterial immunity in the context of salmonid aquaculture. Additionally, the success of current techniques/methods used to combat bacterial diseases in salmonid aquaculture will be addressed. Filling the immunology knowledge gaps highlighted here will assist in reducing aquaculture losses in the future.
Collapse
Affiliation(s)
| | - Brian Dixon
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada;
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Li X, Yang Q, Dierckens K, Milton DL, Defoirdt T. RpoS and indole signaling control the virulence of Vibrio anguillarum towards gnotobiotic sea bass (Dicentrarchus labrax) larvae. PLoS One 2014; 9:e111801. [PMID: 25360804 PMCID: PMC4216140 DOI: 10.1371/journal.pone.0111801] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 10/07/2014] [Indexed: 02/04/2023] Open
Abstract
Quorum sensing, bacterial cell-to-cell communication with small signal molecules, controls the virulence of many pathogens. In contrast to other vibrios, neither the VanI/VanR acylhomoserine lactone quorum sensing system, nor the three-channel quorum sensing system affects virulence of the economically important aquatic pathogen Vibrio anguillarum. Indole is another molecule that recently gained attention as a putative signal molecule. The data presented in this study indicate that indole signaling and the alternative sigma factor RpoS have a significant impact on the virulence of V. anguillarum. Deletion of rpoS resulted in increased expression of the indole biosynthesis gene tnaA and in increased production of indole. Both rpoS deletion and the addition of exogenous indole (50–100 µM) resulted in decreased biofilm formation, exopolysaccharide production (a phenotype that is required for pathogenicity) and expression of the exopolysaccharide synthesis gene wbfD. Further, indole inhibitors increased the virulence of the rpoS deletion mutant, suggesting that indole acts downstream of RpoS. Finally, in addition to the phenotypes found to be affected by indole, the rpoS deletion mutant also showed increased motility and decreased sensitivity to oxidative stress.
Collapse
Affiliation(s)
- Xuan Li
- Laboratory of Aquaculture and Artemia Reference Center, Ghent University, Ghent, Belgium
| | - Qian Yang
- Laboratory of Aquaculture and Artemia Reference Center, Ghent University, Ghent, Belgium
| | - Kristof Dierckens
- Laboratory of Aquaculture and Artemia Reference Center, Ghent University, Ghent, Belgium
| | - Debra L. Milton
- Southern Research Institute, Birmingham, Alabama, United States of America
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Tom Defoirdt
- Laboratory of Aquaculture and Artemia Reference Center, Ghent University, Ghent, Belgium
- Laboratory of Microbial Ecology and Technology, Ghent University, Ghent, Belgium
- * E-mail:
| |
Collapse
|
4
|
Li X, Defoirdt T, Yang Q, Laureau S, Bossier P, Dierckens K. Host-induced increase in larval sea bass mortality in a gnotobiotic challenge test with Vibrio anguillarum. DISEASES OF AQUATIC ORGANISMS 2014; 108:211-216. [PMID: 24695234 DOI: 10.3354/dao02722] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Vibrio anguillarum is the major cause of haemorrhagic septicaemia, vibriosis, which is a severe disease affecting marine fish. In this work, it was found that the mortality of gnotobiotic sea bass larvae challenged with V. anguillarum was dependent on the number of dead fish in the vials at the moment of challenge. Based on this finding, the effect of dead hosts (homogenised sea bass larvae or brine shrimp) on the virulence of V. anguillarum towards sea bass larvae was further investigated. Addition of homogenised hosts led to significantly increased larval mortality of challenged larvae, and this was observed for 3 different V. anguillarum strains, i.e. 43, NB 10 and HI 610. In contrast, the addition of similar levels of tryptone had no effect on mortality. In line with this, the motility of all 3 V. anguillarum strains was significantly increased by the addition of homogenised hosts but not by tryptone. These results suggest that dead hosts increase infectivity of V. anguillarum, not merely by offering nutrients to the bacteria, but also by increasing virulence-associated activities such as motility.
Collapse
Affiliation(s)
- Xuan Li
- Laboratory of Aquaculture & Artemia Reference Center, Ghent University, 9000 Gent, Belgium
| | | | | | | | | | | |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Mutation of a novel virulence-related gene mltD in Vibrio anguillarum enhances lethality in zebra fish. Res Microbiol 2011; 162:144-50. [DOI: 10.1016/j.resmic.2010.08.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 08/30/2010] [Indexed: 11/20/2022]
|
7
|
Naka H, Crosa JH. Genetic Determinants of Virulence in the Marine Fish Pathogen Vibrio anguillarum. FISH PATHOLOGY 2011; 46:1-10. [PMID: 21625345 PMCID: PMC3103123 DOI: 10.3147/jsfp.46.1] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
One of the most studied fish pathogens is Vibrio anguillarum. Development of the genetics and biochemistry of the mechanisms of virulence in this fish pathogen together with clinical and ecologic studies has permitted the intensive development of microbiology in fish diseases. It is the intention of this review to compile the exhaustive knowledge accumulated on this bacterium and its interaction with the host fish by reporting a complete analysis of the V. anguillarum virulence factors and the genetics of their complexity.
Collapse
|
8
|
Mucha A, Drag M, Dalton JP, Kafarski P. Metallo-aminopeptidase inhibitors. Biochimie 2010; 92:1509-29. [PMID: 20457213 PMCID: PMC7117057 DOI: 10.1016/j.biochi.2010.04.026] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 04/29/2010] [Indexed: 01/05/2023]
Abstract
Aminopeptidases are enzymes that selectively hydrolyze an amino acid residue from the N-terminus of proteins and peptides. They are important for the proper functioning of prokaryotic and eukaryotic cells, but very often are central players in the devastating human diseases like cancer, malaria and diabetes. The largest aminopeptidase group include enzymes containing metal ion(s) in their active centers, which often determines the type of inhibitors that are the most suitable for them. Effective ligands mostly bind in a non-covalent mode by forming complexes with the metal ion(s). Here, we present several approaches for the design of inhibitors for metallo-aminopeptidases. The optimized structures should be considered as potential leads in the drug discovery process against endogenous and infectious diseases.
Collapse
Affiliation(s)
- Artur Mucha
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
| | | | | | | |
Collapse
|
9
|
Ma L, Chen J, Liu R, Zhang XH, Jiang YA. Mutation ofrpoS gene decreased resistance to environmental stresses, synthesis of extracellular products and virulence ofVibrio anguillarum. FEMS Microbiol Ecol 2009; 70:130-6. [DOI: 10.1111/j.1574-6941.2009.00713.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
10
|
Yang H, Chen J, Yang G, Zhang XH, Liu R, Xue X. Protection of Japanese flounder (Paralichthys olivaceus) against Vibrio anguillarum with a DNA vaccine containing the mutated zinc-metalloprotease gene. Vaccine 2009; 27:2150-5. [PMID: 19356619 DOI: 10.1016/j.vaccine.2009.01.101] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 01/13/2009] [Accepted: 01/22/2009] [Indexed: 11/24/2022]
Abstract
Vibrio anguillarum is one of the causative agents of vibriosis, a systemic disease of fish characterized by acute hemorrhagic septicemia. The extracellular zinc metalloprotease (EmpA) is a putative virulence factor involved in pathogenicity of V. anguillarum. Here we described the results of immunization against V. anguillarum with the plasmid expressing the mutated EmpA (m-EmpA7), which had no protelytic activity or cytotoxicity. In vitro protein expression of m-empA7 gene was determined by fluorescent microscopy and Western-blot after transfection of Chinese hamster ovary (CHO) and human embryonic kidney (HEK293T) cell lines. All three groups of fish immunized with a single intramuscular (i.m.) injection of different doses of the m-EmpA7 DNA vaccine showed significant serum antibody levels after vaccination, compared with the fish injected with the control eukaryotic expression vector pEGFP-N1 and PBS. In addition, fish receiving the DNA vaccine developed a protective response to a live V. anguillarum challenge 4 weeks post-inoculation, as demonstrated by increased survival of vaccinated fish over the control and by decreased histological alterations in vaccinated fish. Furthermore, humoral immune responses and protective effects were significantly increased at higher vaccine doses using a single intramuscularly injection route.
Collapse
Affiliation(s)
- Hui Yang
- Department of Marine Biology, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China
| | | | | | | | | | | |
Collapse
|
11
|
Identification and characterization of Epp, the secreted processing protease for the Vibrio anguillarum EmpA metalloprotease. J Bacteriol 2008; 190:6589-97. [PMID: 18689477 DOI: 10.1128/jb.00535-08] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The zinc metalloprotease EmpA is a virulence factor for the fish pathogen Vibrio anguillarum. Previous studies demonstrated that EmpA is secreted as a 46-kDa proenzyme that is activated extracellularly by the removal of an approximately 10-kDa propeptide. We hypothesized that a specific protease is responsible for processing secreted pro-EmpA into mature EmpA. To identify the protease responsible for processing pro-EmpA, a minitransposon mutagenesis (using mini-Tn10Km) clone bank of V. anguillarum was screened for reduced protease activity due to insertions in undescribed genes. One mutant with reduced protease activity was identified. The region containing the mini-Tn10Km was cloned, sequenced, and found to contain epp, an open reading frame encoding a putative protease. Further characterization of epp was done using strain M101, created by single-crossover insertional mutagenesis. Protease activity was absent in M101 cultures even when empA protease activity was induced by salmon gastrointestinal mucus. When the epp mutation was complemented with a wild-type copy of epp (M102), protease activity was restored. Western blot analysis of sterile filtered culture supernatants from wild-type (M93Sm) cells, M101 cells, and M102 cells revealed that only pro-EmpA was present in M101supernatants; both pro-EmpA and mature EmpA were detected in M93Sm and M102 supernatants. When sterile filtered culture supernatants from the empA mutant strain (M99) and M101 were mixed, protease activity was restored. Western blot analysis revealed that pro-EmpA in M101 culture supernatant was processed to mature EmpA only after mixing with M99 culture supernatant. These data show that Epp is the EmpA-processing protease.
Collapse
|