scholarly journals Capsid amino acids at positions 247 and 270 are involved in the virulence of betanodaviruses to European sea bass

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Patricia Moreno ◽  
Sandra Souto ◽  
Rocio Leiva-Rebollo ◽  
Juan J. Borrego ◽  
Isabel Bandín ◽  
...  
Keyword(s):  
Amino Acids ◽  
Immune Response ◽  
Fish Species ◽  
Sea Bass ◽  
Fish Mortality ◽  
Wild Type Virus ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
European Sea Bass

Abstract European sea bass (Dicentrarchus labrax) is severely affected by nervous necrosis disease, caused by nervous necrosis virus (NNV). Two out of the four genotypes of this virus (red-spotted grouper nervous necrosis virus, RGNNV; and striped jack nervous necrosis virus, SJNNV) have been detected in sea bass, although showing different levels of virulence to this fish species. Thus, sea bass is highly susceptible to RGNNV, whereas outbreaks caused by SJNNV have not been reported in this fish species. The role of the capsid protein (Cp) amino acids 247 and 270 in the virulence of a RGNNV isolate to sea bass has been evaluated by the generation of recombinant RGNNV viruses harbouring SJNNV-type amino acids in the above mentioned positions (Mut247Dl965, Mut270Dl965 and Mut247 + 270Dl965). Viral in vitro and in vivo replication, virus virulence and fish immune response triggered by these viruses have been analysed. Mutated viruses replicated on E-11 cells, although showing some differences compared to the wild type virus, suggesting that the mutations can affect the viral cell recognition and entry. In vivo, fish mortality caused by mutated viruses was 75% lower, and viral replication in sea bass brain was altered compared to non-mutated virus. Regarding sea bass immune response, mutated viruses triggered a lower induction of IFN I system and inflammatory response-related genes. Furthermore, mutations caused changes in viral serological properties (especially the mutation in amino acid 270), inducing higher seroconversion and changing antigen recognition.

scholarly journals Nervous Necrosis Virus-like Particle (VLP) Vaccine Stimulates European Sea Bass Innate and Adaptive Immune Responses and Induces Long-Term Protection against Disease

Pathogens ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1477
Author(s):  
Sofie Barsøe ◽  
Kerstin Skovgaard ◽  
Dagoberto Sepúlveda ◽  
Ansgar Stratmann ◽  
Niccolò Vendramin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Immune Response ◽  
Expression Analysis ◽  
Gene Expression Analysis ◽  
Sea Bass ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
European Sea Bass ◽  
Post Vaccination ◽  
Virus Like Particle

The rapidly increasing Mediterranean aquaculture production of European sea bass is compromised by outbreaks of viral nervous necrosis, which can be recurrent and detrimental. In this study, we evaluated the duration of protection and immune response in sea bass given a single dose of a virus-like particle (VLP)-based vaccine. Examinations included experimental challenge with nervous necrosis virus (NNV), serological assays for NNV-specific antibody reactivity, and immune gene expression analysis. VLP-vaccinated fish showed high and superior survival in challenge both 3 and 7.5 months (1800 and 4500 dd) post-vaccination (RPS 87 and 88, OR (surviving) = 16.5 and 31.5, respectively, p < 0.01). Although not providing sterile immunity, VLP vaccination seemed to control the viral infection, as indicated by low prevalence of virus in the VLP-vaccinated survivors. High titers of neutralizing and specific antibodies were produced in VLP-vaccinated fish and persisted for at least ~9 months post-vaccination as well as after challenge. However, failure of immune sera to protect recipient fish in a passive immunization trial suggested that other immune mechanisms were important for protection. Accordingly, gene expression analysis revealed that VLP-vaccination induced a mechanistically broad immune response including upregulation of both innate and adaptive humoral and cellular components (mx, isg12, mhc I, mhc II, igm, and igt). No clinical side effects of the VLP vaccination at either tissue or performance levels were observed. The results altogether suggested the VLP-based vaccine to be suitable for clinical testing under farming conditions.

scholarly journals Sea Bass Immunization to Downsize the Betanodavirus Protein Displayed in the Surface of Inactivated Repair-Less Bacteria

Vaccines ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 94
Author(s):  
Lama ◽  
Pereiro ◽  
Novoa ◽  
Coll
Keyword(s):  
Culture Media ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Surface Expression ◽  
Environmental Safety ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
European Sea Bass ◽  
Viral Nervous Necrosis ◽  
Casein Hydrolysates

: This work describes immunization of European sea bass (Dicentrarchus labrax) juveniles against viral nervous necrosis virus (VNNV), a betanodavirus causing worldwide mortalities in many fish species. Protection was obtained with the so-called spinycterin vehicles consisting of irreversibly DNA-damaged DNA-repair-less Escherichia coli displaying at their surface a downsized VNNV coat antigen. In this work we have i) maximized bacterial expression levels by downsizing the coat protein of VNNV to a fragment (frgC91–220) containing most of its previously determined antigenicity, ii) developed a scalable autoinduction culture media for E.coli based in soy-bean rather than in casein hydrolysates, iii) enriched surface expression by screening different anchors from several prokaryotic sources (anchor + frgC91–220 recombinant products), iv) preserved frgC91–220 antigenicity by inactivating bacteria by irreversible DNA-damage by means of Ciprofloxacin, and v) increased safety using a repair-less E.coli strain as chassis for the spinycterins. These spinycterins protected fish against VNNV challenge with partial (Nmistic + frgC91–220) or total (YBEL + frgC91–220) levels of protection, in contrast to fish immunized with frgC91–220 spinycterins. The proposed spinycterin platform has high levels of environmental safety and cost effectiveness and required no adjuvants, thus providing potential to further develop VNNV vaccines for sustainable aquaculture.

scholarly journals Genomic classification of new betanodavirus isolates by phylogenetic analysis of the coat protein gene suggests a low host-fish species specificity

2004 ◽  
Vol 85 (10) ◽  
pp. 3079-3087 ◽  
Author(s):  
Richard Thiéry ◽  
Joëlle Cozien ◽  
Claire de Boisséson ◽  
Soasig Kerbart-Boscher ◽  
Laurent Névarez
Keyword(s):  
Coat Protein ◽  
Virus Type ◽  
Fish Species ◽  
Coat Protein Gene ◽  
Protein Gene ◽  
Sea Bass ◽  
Nervous Necrosis Virus ◽  
Marine Fish Species ◽  
Necrosis Virus ◽  
Host Fish

Viral encephalopathy and retinopathy is a devastating disease that causes neurological disorders and high mortality in a large number of cultivated marine fish species around the world. It is now established that several viral strains classified in the genus Betanodavirus of the family Nodaviridae are the aetiological agents of this disease. Betanodaviruses can be classified into four genotypes based on the coat protein gene sequence. Here, the coat protein genes of the three major strains isolated from sea bass (Dicentrarchus labrax) in France were found to be different. In addition, 21 novel strains of betanodavirus from several fish species from France, Spain, Tunisia and Tahiti were classified by using phylogenetic analysis of a partial sequence (383 nt) of the coat protein gene. Most of the isolates were grouped in the red-spotted grouper nervous necrosis virus type, which was subdivided into two subtypes, one of them containing only French isolates. Furthermore, an isolate obtained from sea bass during an outbreak at low temperature (15 °C) was classified as the barfin flounder nervous necrosis virus type. This is the first reported isolation from sea bass of such a strain, which is known to infect several cold-water marine fish species. In addition, a betanodavirus belonging to the striped jack nervous necrosis virus type was detected in Senagalese sole (Solea senegalensis) farmed in Spain, which is the first indication of the presence of this genotype outside Japan. These findings suggest that the different genotypes can infect a variety of fish species and thus have a low host-fish species specificity.

scholarly journals Different survival of three populations of European sea bass (Dicentrarchus labrax) following challenge with two variants of nervous necrosis virus (NNV)

2021 ◽  
Vol 19 ◽  
pp. 100621
Author(s):  
Sofie Barsøe ◽  
François Allal ◽  
Alain Vergnet ◽  
Marc Vandeputte ◽  
Niels Jørgen Olesen ◽  
...  
Keyword(s):  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
European Sea Bass

scholarly journals Sea Bass Immunization to Downsized Betanodavirus Protein Displayed in The Surface of Dna-Damaged Repair-Less Bacteria

2019 ◽  
Author(s):  
Raquel Lama ◽  
Patricia Pereiro ◽  
Beatriz Novoa ◽  
Julio Coll
Keyword(s):  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Surface Expression ◽  
Environmental Safety ◽  
Small Fish ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
European Sea Bass ◽  
C Protein ◽  
Viral Nervous Necrosis

This work describes practical immunization of European sea bass (Dicentrarchus labrax) juveniles against viral nervous necrosis virus (VNNV), a betanodavirus causing worldwide mortalities in many fish species. Protection was obtained with the so called spinycterin vehicles consisting in irreversibly DNA-damaged DNA-repair-less E.coli displaying at their surface a downsized antigen. In this work we, i) maximized bacterial expression levels by downsizing the C protein to a fragment (frgC91-220) containing most of its antigenicity, ii) developed an scalable autoinduction bacterial media based in soy-bean increasing membrane display and reproducibility, iii) enriched surface expression by screening different anchors from several prokaryotic origins (anchor+frgC91-220), iv) preserved frgC91-220 antigenicity by inactivating bacteria by irreversible DNA-damage by means of Ciprofloxacin, and v) increased safety using a repair-less E.coli strain as spinycterin chassis. These second generation of spinycterins protected fish against VNNV challenge with partial (Nmistic+frgC91-220) or 100 % (YBEL+frgC91-220 ) protection, in contrast to those fish immunized with frgC91-220 spinycterins. The proposed spinycterin platform has high levels of environmental safety and cost effectiveness, thus providing potential for small fish vaccines for sustainable aquaculture.

scholarly journals Transcriptional profile and serological studies of the European sea bass immune response against betanodavirus infections

2019 ◽  
Vol 91 ◽  
pp. 407
Author(s):  
P. Moreno ◽  
B. Lopez-Jimena ◽  
G. Scapigliati ◽  
F. Buonocore ◽  
E. Garcia-Rosado ◽  
...  
Keyword(s):  
Immune Response ◽  
Sea Bass ◽  
Transcriptional Profile ◽  
European Sea Bass ◽  
Serological Studies

scholarly journals Potential Involvement of lncRNAs in the Modulation of the Transcriptome Response to Nodavirus Challenge in European Sea Bass (Dicentrarchus labrax L.)

Biology ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 165
Author(s):  
Patricia Pereiro ◽  
Raquel Lama ◽  
Rebeca Moreira ◽  
Valentina Valenzuela-Muñoz ◽  
Cristian Gallardo-Escárate ◽  
...  
Keyword(s):  
Immune Response ◽  
Dicentrarchus Labrax ◽  
Head Kidney ◽  
Enrichment Analysis ◽  
Sea Bass ◽  
Integrated Analysis ◽  
European Sea Bass ◽  
Commercial Species ◽  
Number Of Publications ◽  
Systematic Identification

Long noncoding RNAs (lncRNAs) are being increasingly recognised as key modulators of various biological mechanisms, including the immune response. Although investigations in teleosts are still lagging behind those conducted in mammals, current research indicates that lncRNAs play a pivotal role in the response of fish to a variety of pathogens. During the last several years, interest in lncRNAs has increased considerably, and a small but notable number of publications have reported the modulation of the lncRNA profile in some fish species after pathogen challenge. This study was the first to identify lncRNAs in the commercial species European sea bass. A total of 12,158 potential lncRNAs were detected in the head kidney and brain. We found that some lncRNAs were not common for both tissues, and these lncRNAs were located near coding genes that are primarily involved in tissue-specific processes, reflecting a degree of cellular specialisation in the synthesis of lncRNAs. Moreover, lncRNA modulation was analysed in both tissues at 24 and 72 h after infection with nodavirus. Enrichment analysis of the neighbouring coding genes of the modulated lncRNAs revealed many terms related to the immune response and viral infectivity but also related to the stress response. An integrated analysis of the lncRNAs and coding genes showed a strong correlation between the expression of the lncRNAs and their flanking coding genes. Our study represents the first systematic identification of lncRNAs in European sea bass and provides evidence regarding the involvement of these lncRNAs in the response to nodavirus.

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