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Jiménez-Meléndez A, Shakya R, Markussen T, Robertson LJ, Myrmel M, Makvandi-Nejad S. Gene expression profile of HCT-8 cells following single or co-infections with Cryptosporidium parvum and bovine coronavirus. Sci Rep 2023; 13:22106. [PMID: 38092824 PMCID: PMC10719361 DOI: 10.1038/s41598-023-49488-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 12/08/2023] [Indexed: 12/17/2023] Open
Abstract
Among the causative agents of neonatal diarrhoea in calves, two of the most prevalent are bovine coronavirus (BCoV) and the intracellular parasite Cryptosporidium parvum. Although several studies indicate that co-infections are associated with greater symptom severity, the host-pathogen interplay remains unresolved. Here, our main objective was to investigate the modulation of the transcriptome of HCT-8 cells during single and co-infections with BCoV and C. parvum. For this, HCT-8 cells were inoculated with (1) BCoV alone, (2) C. parvum alone, (3) BCoV and C. parvum simultaneously. After 24 and 72 h, cells were harvested and analyzed using high-throughput RNA sequencing. Following differential expression analysis, over 6000 differentially expressed genes (DEGs) were identified in virus-infected and co-exposed cells at 72 hpi, whereas only 52 DEGs were found in C. parvum-infected cells at the same time point. Pathway (KEGG) and gene ontology (GO) analysis showed that DEGs in the virus-infected and co-exposed cells were mostly associated with immune pathways (such as NF-κB, TNF-α or, IL-17), apoptosis and regulation of transcription, with a more limited effect exerted by C. parvum. Although the modulation observed in the co-infection was apparently dominated by the virus, over 800 DEGs were uniquely expressed in co-exposed cells at 72 hpi. Our findings provide insights on possible biomarkers associated with co-infection, which could be further explored using in vivo models.
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Affiliation(s)
- Alejandro Jiménez-Meléndez
- Department of Paraclinical Sciences (PARAFAG), Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway.
| | - Ruchika Shakya
- Department of Paraclinical Sciences (PARAFAG), Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Turhan Markussen
- Department of Paraclinical Sciences (PARAFAG), Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Lucy J Robertson
- Department of Paraclinical Sciences (PARAFAG), Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Mette Myrmel
- Department of Paraclinical Sciences (PARAFAG), Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Shokouh Makvandi-Nejad
- Research Group Animal Health, Vaccinology, Norwegian Veterinary Institute, Ås, Norway
- Nykode Therapeutics ASA, Oslo Science Park, Oslo, Norway
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Arnesen H, Markussen T, Birchenough G, Birkeland S, Nyström EEL, Hansson GC, Carlsen H, Boysen P. Microbial experience through housing in a farmyard-type environment alters intestinal barrier properties in mouse colons. Sci Rep 2023; 13:13701. [PMID: 37607995 PMCID: PMC10444815 DOI: 10.1038/s41598-023-40640-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 08/14/2023] [Indexed: 08/24/2023] Open
Abstract
To close the gap between ultra-hygienic research mouse models and the much more environmentally exposed conditions of humans, we have established a system where laboratory mice are raised under a full set of environmental factors present in a naturalistic, farmyard-type habitat-a process we have called feralization. In previous studies we have shown that feralized (Fer) mice were protected against colorectal cancer when compared to conventionally reared laboratory mice (Lab). However, the protective mechanisms remain to be elucidated. Disruption of the protective intestinal barrier is an acknowledged player in colorectal carcinogenesis, and in the current study we assessed colonic mucosal barrier properties in healthy, feralized C57BL/6JRj male mice. While we found no effect of feralization on mucus layer properties, higher expression of genes encoding the mucus components Fcgbp and Clca1 still suggested mucus enforcement due to feralization. Genes encoding other proteins known to be involved in bacterial defense (Itln1, Ang1, Retnlb) and inflammatory mechanisms (Zbp1, Gsdmc2) were also higher expressed in feralized mice, further suggesting that the Fer mice have an altered intestinal mucosal barrier. These findings demonstrate that microbial experience conferred by housing in a farmyard-type environment alters the intestinal barrier properties in mice possibly leading to a more robust protection against disease. Future studies to unravel regulatory roles of feralization on intestinal barrier should aim to conduct proteomic analyses and in vivo performance of the feralized mice intestinal barrier.
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Affiliation(s)
- Henriette Arnesen
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Turhan Markussen
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - George Birchenough
- Mucin Biology Group, Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Signe Birkeland
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Elisabeth E L Nyström
- Mucin Biology Group, Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Gunnar C Hansson
- Mucin Biology Group, Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Harald Carlsen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Preben Boysen
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway.
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Aksnes I, Braaen S, Markussen T, Åkesson CP, Villoing S, Rimstad E. Genetically modified attenuated salmonid alphavirus: A potential strategy for immunization of Atlantic salmon. J Fish Dis 2021; 44:923-937. [PMID: 33591590 DOI: 10.1111/jfd.13352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/29/2021] [Accepted: 01/31/2021] [Indexed: 06/12/2023]
Abstract
Pancreas disease (PD) is a serious challenge in European salmonid aquaculture caused by salmonid alphavirus (SAV). In this study, we report the effect of immunization of Atlantic salmon with three attenuated infectious SAV3 strains with targeted mutations in a glycosylation site of the envelope E2 protein and/or in a nuclear localization signal in the capsid protein. In a pilot experiment, it was shown that the mutated viral strains replicated in fish, transmitted to naïve cohabitants and that the transmission had not altered the sequences. In the main experiment, the fish were immunized with the strains and challenged with SAV3 eight weeks after immunization. Immunization resulted in infection both in injected fish and 2 weeks later in the cohabitant fish, followed by a persistent but declining load of the mutated virus variants in the hearts. The immunized fish developed clinical signs and pathology consistent with PD prior to challenge. However, fish injected with the virus mutated in both E2 and capsid showed little clinical signs and had higher average weight gain than the groups immunized with the single mutated variants. The SAV strain used for challenge was not detected in the immunized fish indicating that these fish were protected against superinfection with SAV during the 12 weeks of the experiment.
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Affiliation(s)
- Ida Aksnes
- Department of Paraclinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
| | - Stine Braaen
- Department of Paraclinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
| | - Turhan Markussen
- Department of Paraclinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
| | | | | | - Espen Rimstad
- Department of Paraclinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
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Aksnes I, Markussen T, Braaen S, Rimstad E. Mutation of N-glycosylation Sites in Salmonid Alphavirus (SAV) Envelope Proteins Attenuate the Virus in Cell Culture. Viruses 2020; 12:v12101071. [PMID: 32987930 PMCID: PMC7650630 DOI: 10.3390/v12101071] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 12/16/2022] Open
Abstract
Salmonid alphavirus (SAV) is the cause of pancreas disease and sleeping disease in farmed salmonid fish in Europe. The spread of these diseases has been difficult to control with biosecurity and current vaccination strategies, and increased understanding of the viral pathogenesis could be beneficial for the development of novel vaccine strategies. N-glycosylation of viral envelope proteins may be crucial for viral virulence and a possible target for its purposed attenuation. In this study, we mutated the N-glycosylation consensus motifs of the E1 and E2 glycoproteins of a SAV3 infectious clone using site-directed mutagenesis. Mutation of the glycosylation motif in E1 gave a complete inactivation of the virus as no viral replication could be detected in cell culture and infectious particles could not be rescued. In contrast, infectious virus particles could be recovered from the SAV3 E2 mutants (E2319Q, E2319A), but not if they were accompanied by lack of N-glycosylation in E1. Compared to the non-mutated infectious clone, the SAV3-E2319Q and SAV3-E2319A recombinant viruses produced less cytopathic effects in cell culture and lower amounts of infectious viral particles. In conclusion, the substitution in the N-linked glycosylation site in E2 attenuated SAV3 in cell culture. The findings could be useful for immunization strategies using live attenuated vaccines and testing in fish will be desirable to study the clone’s properties in vivo.
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Rimstad E, Markussen T. Infectious salmon anaemia virus-molecular biology and pathogenesis of the infection. J Appl Microbiol 2020; 129:85-97. [PMID: 31885186 DOI: 10.1111/jam.14567] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 12/20/2019] [Accepted: 12/23/2019] [Indexed: 11/29/2022]
Abstract
Aquaculture has a long history in many parts of the world, but it is still young at an industrial scale. Marine fish farming in open nets of a single fish species at high densities compared to their wild compatriots opens a plethora of possible infections. Infectious salmon anaemia (ISA) is an example of disease that surfaced after large-scale farming of Atlantic salmon (Salmo salar) appeared. Here, a review of the molecular biology of the ISA virus (ISAV) with emphasis on its pathogenicity is presented. The avirulent HPR0 variant of ISAV has resisted propagation in cell cultures, which has restricted the ability to perform in vivo experiments with this variant. The transition from avirulent HPR0 to virulent HPRΔ has not been methodically studied under controlled experimental conditions, and the triggers of the transition from avirulent to virulent forms have not been mapped. Genetic segment reassortment, recombination and mutations are important mechanisms in ISAV evolution, and for the development of virulence. In the 25 years since the ISAV was identified, large amounts of sequence data have been collected for epidemiologic and transmission studies, however, the lack of good experimental models for HPR0 make the risk evaluation of the presence of this avirulent, ubiquitous variant uncertain. This review summarizes the current knowledge related to molecular biology and pathogenicity of this important aquatic orthomyxovirus.
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Affiliation(s)
- E Rimstad
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - T Markussen
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
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Rusch JC, Hansen H, Strand DA, Markussen T, Hytterød S, Vrålstad T. Catching the fish with the worm: a case study on eDNA detection of the monogenean parasite Gyrodactylus salaris and two of its hosts, Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss). Parasit Vectors 2018; 11:333. [PMID: 29866158 PMCID: PMC5987472 DOI: 10.1186/s13071-018-2916-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 05/25/2018] [Indexed: 01/20/2023] Open
Abstract
Background Environmental DNA (eDNA) monitoring is growing increasingly popular in aquatic systems as a valuable complementary method to conventional monitoring. However, such tools have not yet been extensively applied for metazoan fish parasite monitoring. The fish ectoparasite Gyrodactylus salaris, introduced into Norway in 1975, has caused severe damage to Atlantic salmon populations and fisheries. Successful eradication of the parasite has been carried out in several river systems in Norway, and Atlantic salmon remain infected in only seven rivers, including three in the Drammen region. In this particular infection region, a prerequisite for treatment is to establish whether G. salaris is also present on rainbow trout upstream of the salmon migration barrier. Here, we developed and tested eDNA approaches to complement conventional surveillance methods. Methods Water samples (2 × 5 l) were filtered on-site through glass fibre filters from nine locations in the Drammen watercourse, and DNA was extracted with a CTAB protocol. We developed a qPCR assay for G. salaris targeting the nuclear ribosomal ITS1 region, and we implemented published assays targeting the mitochondrial cytochrome-b and NADH-regions for Atlantic salmon and rainbow trout, respectively. All assays were transferred successfully to droplet digital PCR (ddPCR). Results All qPCR/ddPCR assays performed well both on tissue samples and on field samples, demonstrating the applicability of eDNA detection for G. salaris, rainbow trout and Atlantic salmon in natural water systems. With ddPCR we eliminated a low cross-amplification of Gyrodactylus derjavinoides observed using qPCR, thus increasing specificity and sensitivity substantially. Duplex ddPCR for G. salaris and Atlantic salmon was successfully implemented and can be used as a method in future surveillance programs. The presence of G. salaris eDNA in the infected River Lierelva was documented, while not elsewhere. Rainbow trout eDNA was only detected at localities where the positives could be attributed to eDNA release from upstream land-based rainbow trout farms. Electrofishing supported the absence of rainbow trout in all of the localities. Conclusions We provide a reliable field and laboratory protocol for eDNA detection of G. salaris, Atlantic salmon and rainbow trout, that can complement conventional surveillance programs and substantially reduce the sacrifice of live fish. We also show that ddPCR outperforms qPCR with respect to the specific detection of G. salaris.
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Affiliation(s)
- Johannes C Rusch
- Norwegian Veterinary Institute, P.O. Box 750, Sentrum, NO-0106, Oslo, Norway.,Department of Biosciences, University of Oslo, P.O. Box 1066, Blindern, NO-0316, Oslo, Norway
| | - Haakon Hansen
- Norwegian Veterinary Institute, P.O. Box 750, Sentrum, NO-0106, Oslo, Norway.
| | - David A Strand
- Norwegian Veterinary Institute, P.O. Box 750, Sentrum, NO-0106, Oslo, Norway
| | - Turhan Markussen
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, P.O. Box 8146, Dep, NO-0033, Oslo, Norway
| | - Sigurd Hytterød
- Norwegian Veterinary Institute, P.O. Box 750, Sentrum, NO-0106, Oslo, Norway
| | - Trude Vrålstad
- Norwegian Veterinary Institute, P.O. Box 750, Sentrum, NO-0106, Oslo, Norway
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Nylund A, Hansen H, Brevik ØJ, Hustoft H, Markussen T, Plarre H, Karlsbakk E. Infection dynamics and tissue tropism of Parvicapsula pseudobranchicola (Myxozoa: Myxosporea) in farmed Atlantic salmon (Salmo salar). Parasit Vectors 2018; 11:17. [PMID: 29306320 PMCID: PMC5756351 DOI: 10.1186/s13071-017-2583-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 12/11/2017] [Indexed: 11/10/2022] Open
Abstract
Background The myxosporean parasite Parvicapsula pseudobranchicola commonly infects farmed Atlantic salmon in northern Norway. Heavy infections are associated with pseudobranch lesions, runting and mortality in the salmon populations. The life-cycle of the parasite is unknown, preventing controlled challenge experiments. The infection dynamics, duration of sporogony, tissue tropism and ability to develop immunity to the parasite in farmed Atlantic salmon is poorly known. We conducted a field experiment, aiming at examining these aspects. Methods Infections in a group of Atlantic salmon were followed from before sea-transfer to the end of the production (604 days). Samples from a range of tissues/sites were analysed using real-time RT-PCR and histology, including in situ hybridization. Results All salmon in the studied population rapidly became infected with P. pseudobranchicola after sea-transfer medio August. Parasite densities in the pseudobranchs peaked in winter (November-January), and decreased markedly to March. Densities thereafter decreased further. Parasite densities in other tissues were low. Parasite stages were initially found to be intravascular in the pseudobranch, but occurred extravascular in the pseudobranch tissue at 3 months post-sea-transfer. Mature spores appeared in the pseudobranchs in the period with high parasite densities in the winter (late November-January), and were released (i.e. disappeared from the fish) in the period January-March. Clinical signs of parvicapsulosis (December-early February) were associated with high parasite densities and inflammation in the pseudobranchs. No evidence for reinfection was seen the second autumn in sea. Conclusions The main site of the parasite in Atlantic salmon is the pseudobranchs. Blood stages occur, but parasite proliferation is primarily associated with extravascular stages in the pseudobranchs. Disease and mortality (parvicapsulosis) coincide with the completion of sporogony. Atlantic salmon appears to develop immunity to P. pseudobranchicola. Further studies should focus on the unknown life-cycle of the parasite, and the pathophysiological effects of the pseudobranch infection that also could affect the eyes and vision. Electronic supplementary material The online version of this article (10.1186/s13071-017-2583-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Are Nylund
- Department of Biology, University of Bergen, 5020, Bergen, Norway
| | - Haakon Hansen
- Norwegian Veterinary Institute, PO Box 750 Sentrum, N-0106, Oslo, Norway
| | - Øyvind J Brevik
- Cermaq group AS, Dronning Eufemias gate16, P.O. Box 144, N-0102, Oslo, Norway
| | - Håvard Hustoft
- Department of Biology, University of Bergen, 5020, Bergen, Norway
| | - Turhan Markussen
- Norwegian Veterinary Institute, PO Box 750 Sentrum, N-0106, Oslo, Norway.,Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Heidrun Plarre
- Department of Biology, University of Bergen, 5020, Bergen, Norway
| | - Egil Karlsbakk
- Department of Biology, University of Bergen, 5020, Bergen, Norway. .,Institute of Marine Research, PO Box 1870, Nordnes, N-5817, Bergen, Norway.
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Büyükekiz AG, Altun S, Hansen EF, Satıcıoğlu IB, Duman M, Markussen T, Rimstad E. Infectious pancreatic necrosis virus (IPNV) serotype Sp is prevalent in Turkish rainbow trout farms. J Fish Dis 2018; 41:95-104. [PMID: 28745835 DOI: 10.1111/jfd.12675] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 05/29/2017] [Accepted: 05/30/2017] [Indexed: 06/07/2023]
Abstract
Infectious pancreatic necrosis virus (IPNV) is a common pathogen of rainbow trout (Oncorhynchus mykiss) in Turkey. We found that 455 of 1,676 sample pools tested were IPNV positive. Positive samples were found in all geographical regions where sampling was conducted. Sequence and phylogenetic analyses of VP2 from 30 isolates representing all regions showed that the viruses were highly similar in sequence and grouped within Genogroup 5 (serotype Sp-A2). No correlations between sequences, sampling sites or geographical origins were identified. Although clinical disease was evident in several farms, analyses of the amino acid sequence of VP2 showed that all virus strains harboured the P217 T221 motif, assumed to be associated with low virulence. We conclude that IPNV is prevalent in Turkish rainbow trout farms and that the viruses are very homogenous and likely to be of European origin. Frequent exchange of eggs and live fish within the farming industry may explain the homogeneity of the IPNV.
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Affiliation(s)
- A G Büyükekiz
- Department of Aquatic Animal Diseases, Faculty of Veterinary Medicine, Uludag University, Bursa, Turkey
| | - S Altun
- Department of Aquatic Animal Diseases, Faculty of Veterinary Medicine, Uludag University, Bursa, Turkey
| | - E F Hansen
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - I B Satıcıoğlu
- Department of Aquatic Animal Diseases, Faculty of Veterinary Medicine, Uludag University, Bursa, Turkey
| | - M Duman
- Department of Aquatic Animal Diseases, Faculty of Veterinary Medicine, Uludag University, Bursa, Turkey
| | - T Markussen
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - E Rimstad
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
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Wessel Ø, Braaen S, Alarcon M, Haatveit H, Roos N, Markussen T, Tengs T, Dahle MK, Rimstad E. Infection with purified Piscine orthoreovirus demonstrates a causal relationship with heart and skeletal muscle inflammation in Atlantic salmon. PLoS One 2017; 12:e0183781. [PMID: 28841684 PMCID: PMC5571969 DOI: 10.1371/journal.pone.0183781] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 08/10/2017] [Indexed: 01/07/2023] Open
Abstract
Viral diseases pose a significant threat to the productivity in aquaculture. Heart- and skeletal muscle inflammation (HSMI) is an emerging disease in Atlantic salmon (Salmo salar) farming. HSMI is associated with Piscine orthoreovirus (PRV) infection, but PRV is ubiquitous in farmed Atlantic salmon and thus present also in apparently healthy individuals. This has brought speculations if additional etiological factors are required, and experiments focusing on the causal relationship between PRV and HSMI are highly warranted. A major bottleneck in PRV research has been the lack of cell lines that allow propagation of the virus. To bypass this, we propagated PRV in salmon, bled the fish at the peak of the infection, and purified virus particles from blood cells. Electron microscopy, western blot and high-throughput sequencing all verified the purity of the viral particles. Purified PRV particles were inoculated into naïve Atlantic salmon. The purified virus replicated in inoculated fish, spread to naïve cohabitants, and induced histopathological changes consistent with HSMI. PRV specific staining was demonstrated in the pathological lesions. A dose-dependent response was observed; a high dose of virus gave earlier peak of the viral load and development of histopathological changes compared to a lower dose, but no difference in the severity of the disease. The experiment demonstrated that PRV can be purified from blood cells, and that PRV is the etiological agent of HSMI in Atlantic salmon.
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Affiliation(s)
- Øystein Wessel
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
- * E-mail:
| | - Stine Braaen
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | | | - Hanne Haatveit
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Norbert Roos
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Turhan Markussen
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Torstein Tengs
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | | | - Espen Rimstad
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
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Røsæg MV, Lund M, Nyman IB, Markussen T, Aspehaug V, Sindre H, Dahle MK, Rimstad E. Immunological interactions between Piscine orthoreovirus and Salmonid alphavirus infections in Atlantic salmon. Fish Shellfish Immunol 2017; 64:308-319. [PMID: 28323214 DOI: 10.1016/j.fsi.2017.03.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 03/14/2017] [Accepted: 03/17/2017] [Indexed: 06/06/2023]
Abstract
Heart and skeletal muscle inflammation (HSMI) and pancreas disease (PD) cause substantial losses in Atlantic salmon (Salmo salar) aquaculture. The respective causative agents, Piscine orthoreovirus (PRV) and Salmonid alphavirus (SAV), are widespread and often concurrently present in farmed salmon. An experimental infection in Atlantic salmon was conducted to study the interaction between the two viruses, including the immunological mechanisms involved. The co-infected fish were infected with PRV four or ten weeks before they were infected with SAV. The SAV RNA level and the PD specific lesions were significantly lower in co-infected groups compared to the group infected by only SAV. The expression profiles of a panel of innate antiviral response genes and the plasma SAV neutralization titers were examined. The innate antiviral response genes were in general upregulated for at least ten weeks after the primary PRV infection. Plasma from co-infected fish had lower SAV neutralizing titers compared to the controls infected with only SAV. Plasma from some individuals infected with only PRV neutralized SAV, but heat treatment removed this effect. Field studies of co-infected fish populations indicated a negative correlation between the two viruses in randomly sampled apparently healthy fish, in line with the experimental findings, but a positive correlation in moribund or dead fish. The results indicate that the innate antiviral response induced by PRV may temporary protect against a secondary SAV infection.
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Affiliation(s)
- Magnus Vikan Røsæg
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway; SalMar ASA, Kverva, Norway
| | - Morten Lund
- Sections of Immunology and Virology, Norwegian Veterinary Institute, Oslo, Norway
| | - Ingvild Berg Nyman
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Turhan Markussen
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | | | - Hilde Sindre
- Sections of Immunology and Virology, Norwegian Veterinary Institute, Oslo, Norway
| | - Maria Krudtaa Dahle
- Sections of Immunology and Virology, Norwegian Veterinary Institute, Oslo, Norway
| | - Espen Rimstad
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway.
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11
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Haatveit HM, Wessel Ø, Markussen T, Lund M, Thiede B, Nyman IB, Braaen S, Dahle MK, Rimstad E. Viral Protein Kinetics of Piscine Orthoreovirus Infection in Atlantic Salmon Blood Cells. Viruses 2017; 9:v9030049. [PMID: 28335455 PMCID: PMC5371804 DOI: 10.3390/v9030049] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/07/2017] [Accepted: 03/10/2017] [Indexed: 01/12/2023] Open
Abstract
Piscine orthoreovirus (PRV) is ubiquitous in farmed Atlantic salmon (Salmo salar) and the cause of heart and skeletal muscle inflammation. Erythrocytes are important target cells for PRV. We have investigated the kinetics of PRV infection in salmon blood cells. The findings indicate that PRV causes an acute infection of blood cells lasting 1–2 weeks, before it subsides into persistence. A high production of viral proteins occurred initially in the acute phase which significantly correlated with antiviral gene transcription. Globular viral factories organized by the non-structural protein µNS were also observed initially, but were not evident at later stages. Interactions between µNS and the PRV structural proteins λ1, µ1, σ1 and σ3 were demonstrated. Different size variants of µNS and the outer capsid protein µ1 appeared at specific time points during infection. Maximal viral protein load was observed five weeks post cohabitant challenge and was undetectable from seven weeks post challenge. In contrast, viral RNA at a high level could be detected throughout the eight-week trial. A proteolytic cleavage fragment of the µ1 protein was the only viral protein detectable after seven weeks post challenge, indicating that this µ1 fragment may be involved in the mechanisms of persistent infection.
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Affiliation(s)
- Hanne Merethe Haatveit
- Department of Food Safety and Infectious Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway.
| | - Øystein Wessel
- Department of Food Safety and Infectious Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway.
| | - Turhan Markussen
- Department of Food Safety and Infectious Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway.
| | - Morten Lund
- Department of Immunology, Norwegian Veterinary Institute, 0454 Oslo, Norway.
| | - Bernd Thiede
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
| | - Ingvild Berg Nyman
- Department of Food Safety and Infectious Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway.
| | - Stine Braaen
- Department of Food Safety and Infectious Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway.
| | - Maria Krudtaa Dahle
- Department of Immunology, Norwegian Veterinary Institute, 0454 Oslo, Norway.
| | - Espen Rimstad
- Department of Food Safety and Infectious Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway.
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12
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Bessis C, Della Rocca ML, Barraud C, Martin P, Lacroix JC, Markussen T, Lafarge P. Probing electron-phonon excitations in molecular junctions by quantum interference. Sci Rep 2016; 6:20899. [PMID: 26864735 PMCID: PMC4750039 DOI: 10.1038/srep20899] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/12/2016] [Indexed: 12/31/2022] Open
Abstract
Electron-phonon coupling is a fundamental inelastic interaction in condensed matter and in molecules. Here we probe phonon excitations using quantum interference in electron transport occurring in short chains of anthraquinone based molecular junctions. By studying the dependence of molecular junction’s conductance as a function of bias voltage and temperature, we show that inelastic scattering of electrons by phonons can be detected as features in conductance resulting from quenching of quantum interference. Our results are in agreement with density functional theory calculations and are well described by a generic two-site model in the framework of non-equilibrium Green’s functions formalism. The importance of the observed inelastic contribution to the current opens up new ways for exploring coherent electron transport through molecular devices.
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Affiliation(s)
- C Bessis
- Université Paris Diderot, Sorbonne Paris Cité, MPQ, UMR 7162, CNRS, 75205 Paris Cedex 13, France
| | - M L Della Rocca
- Université Paris Diderot, Sorbonne Paris Cité, MPQ, UMR 7162, CNRS, 75205 Paris Cedex 13, France
| | - C Barraud
- Université Paris Diderot, Sorbonne Paris Cité, MPQ, UMR 7162, CNRS, 75205 Paris Cedex 13, France
| | - P Martin
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086, CNRS, 15 rue J.-A. de Baïf, 75205 Paris Cedex 13, France
| | - J C Lacroix
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086, CNRS, 15 rue J.-A. de Baïf, 75205 Paris Cedex 13, France
| | - T Markussen
- QuantumWise A/S, Fruebjergvej 3, Box 4, DK-2100 Copenhagen, Denmark
| | - P Lafarge
- Université Paris Diderot, Sorbonne Paris Cité, MPQ, UMR 7162, CNRS, 75205 Paris Cedex 13, France
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13
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Fourrier M, Lester K, Markussen T, Falk K, Secombes CJ, McBeath A, Collet B. Dual Mutation Events in the Haemagglutinin-Esterase and Fusion Protein from an Infectious Salmon Anaemia Virus HPR0 Genotype Promote Viral Fusion and Activation by an Ubiquitous Host Protease. PLoS One 2015; 10:e0142020. [PMID: 26517828 PMCID: PMC4627773 DOI: 10.1371/journal.pone.0142020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 10/15/2015] [Indexed: 11/24/2022] Open
Abstract
In Infectious salmon anaemia virus (ISAV), deletions in the highly polymorphic region (HPR) in the near membrane domain of the haemagglutinin-esterase (HE) stalk, influence viral fusion. It is suspected that selected mutations in the associated Fusion (F) protein may also be important in regulating fusion activity. To better understand the underlying mechanisms involved in ISAV fusion, several mutated F proteins were generated from the Scottish Nevis and Norwegian SK779/06 HPR0. Co-transfection with constructs encoding HE and F were performed, fusion activity assessed by content mixing assay and the degree of proteolytic cleavage by western blot. Substitutions in Nevis F demonstrated that K276 was the most likely cleavage site in the protein. Furthermore, amino acid substitutions at three sites and two insertions, all slightly upstream of K276, increased fusion activity. Co-expression with HE harbouring a full-length HPR produced high fusion activities when trypsin and low pH were applied. In comparison, under normal culture conditions, groups containing a mutated HE with an HPR deletion were able to generate moderate fusion levels, while those with a full length HPR HE could not induce fusion. This suggested that HPR length may influence how the HE primes the F protein and promotes fusion activation by an ubiquitous host protease and/or facilitate subsequent post-cleavage refolding steps. Variations in fusion activity through accumulated mutations on surface glycoproteins have also been reported in other orthomyxoviruses and paramyxoviruses. This may in part contribute to the different virulence and tissue tropism reported for HPR0 and HPR deleted ISAV genotypes.
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Affiliation(s)
- Mickael Fourrier
- Aquaculture and Fish Health, Marine Scotland Science, Aberdeen, United Kingdom
- * E-mail:
| | - Katherine Lester
- Aquaculture and Fish Health, Marine Scotland Science, Aberdeen, United Kingdom
| | | | - Knut Falk
- Epidemiology, Norwegian Veterinary Institute, Oslo, Norway
| | | | - Alastair McBeath
- Aquaculture and Fish Health, Marine Scotland Science, Aberdeen, United Kingdom
| | - Bertrand Collet
- Aquaculture and Fish Health, Marine Scotland Science, Aberdeen, United Kingdom
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14
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Hansen H, Poppe TT, Markussen T, Karlsbakk E. Seatrout (Salmo trutta) is a natural host for Parvicapsula pseudobranchicola (Myxozoa, Myxosporea), an important pathogen of farmed Atlantic salmon (Salmo salar). Parasit Vectors 2015; 8:218. [PMID: 25890219 PMCID: PMC4397713 DOI: 10.1186/s13071-015-0828-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 03/25/2015] [Indexed: 11/10/2022] Open
Abstract
Background Parvicapsula pseudobranchicola (Myxozoa) causes widespread infections in farmed Atlantic salmon in northern Norway. Heavily infected salmon become runts, probably due to vision impairment or blindness. The salmon are likely infected by waterborne actinospores, released by an alternating annelid host, but the life cycle of P. pseudobranchicola is unknown. Seatrout and Arctic charr have been considered possible hosts for the parasite, but firm evidence has been lacking. Findings We show for the first time the presence of mature spores of P. pseudobranchicola in seatrout. The seatrout were infected with high intensities of P. pseudobranchicola in the pseudobranchs in early April. The presence of mature spores in early spring suggests that the fish had been infected late the previous year, a pattern of infection similar to that observed for farmed salmon stocked in autumn. Although heavily infected, the fish did not display any symptoms consistent with parvicapsulosis. The results suggest that the life cycle of P. pseudobranchicola is more adapted to seatrout, rather than to Atlantic salmon. Conclusions The presence of mature spores of P. pseudobranchicola in seatrout confirms that seatrout is a natural host for this myxosporean and this is also the first record of these spores in the pseudobranch of a wild salmonid. Furthermore, wild trout from non-farming areas may become heavily infected with P. pseudobranchicola, developing pseudobranch pathology resembling that of farmed Atlantic salmon suffering from parvicapsulosis.
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Affiliation(s)
- Haakon Hansen
- Norwegian Veterinary Institute, P.O. Box 750 Sentrum, N-0106, Oslo, Norway.
| | - Trygve T Poppe
- Norwegian Veterinary Institute, P.O. Box 750 Sentrum, N-0106, Oslo, Norway. .,Norwegian University of Life Sciences, School of Veterinary Medicine, P.O. Box 5003, N-1432, Ås, Norway.
| | - Turhan Markussen
- Norwegian Veterinary Institute, P.O. Box 750 Sentrum, N-0106, Oslo, Norway.
| | - Egil Karlsbakk
- Institute of Marine Research, P.O. Box 1870, 5817, Nordnes Bergen, Norway.
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15
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Markussen T, Agusti C, Karlsbakk E, Nylund A, Brevik Ø, Hansen H. Detection of the myxosporean parasite Parvicapsula pseudobranchicola in Atlantic salmon (Salmo salar L.) using in situ hybridization (ISH). Parasit Vectors 2015; 8:105. [PMID: 25889266 PMCID: PMC4334612 DOI: 10.1186/s13071-015-0718-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 02/05/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Parvicapsula pseudobranchicola is a marine myxosporean parasite infecting farmed Atlantic salmon (Salmo salar). A major site for the parasite is the pseudobranch, which may be destroyed in heavily infected fish. Parvicapsulosis may be associated with significant mortality, although the main effect of infections seems to be runting. In situ hybridization (ISH) is, in the absence of specific antibodies, the preferred method for the detection of cell- and tissue tropisms of myxozoans in the early phases of infection of the host, and provides information about the possible association between the pathogen and pathology. A positive diagnosis of parvicapsulosis is based on histopathology and PCR. The aim of the present work was to develop a specific, sensitive and robust ISH assay for the detection of P. pseudobranchicola in tissues. METHODS The ISH method was designed to specifically target P. pseudobranchicola 18S rDNA/rRNA using a locked nucleic acid (LNA) modified oligonucleotide probe. The method was tested on paraffin embedded P. pseudobranchicola infected pseudobranchs. The infections were confirmed by light microscopy revealing the presence of typical P. pseudobranchicola trophozoites and spores, and the presence of parasite was confirmed with real-time RT-PCR. RESULTS Specific regions stained by ISH overlapped well with the parasitized and degenerated regions in neighbouring HE stained sections. No staining was observed in pseudobranchs of Atlantic salmon which had been held in P. pseudobranchicola-free water. CONCLUSIONS We report here the development of a sensitive ISH assay for the detection of P. pseudobranchicola in paraffin embedded tissue. The technique will be valuable in the study of host entry, early proliferation, pre-spore development, pathology and tissue tropism in Atlantic salmon.
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Affiliation(s)
- Turhan Markussen
- Norwegian Veterinary Institute, P.O. Box 750 Sentrum, , N-0106, Oslo, Norway.
| | - Celia Agusti
- Norwegian Veterinary Institute, P.O. Box 750 Sentrum, , N-0106, Oslo, Norway. .,Present address: Institute of Food Safety and Infection Biology, Norwegian University of Life Sciences, P.O. Box 8146, , Dep., NO-0033, Oslo, Norway.
| | - Egil Karlsbakk
- Institute of Marine Research, P.O. Box 1870, , Nordnes, 5817, Bergen, Norway.
| | - Are Nylund
- Department of Biology, University of Bergen, Thormøhlensgt 55, N-5020, Bergen, Norway.
| | - Øyvind Brevik
- Cermaq Group AS, Dronning Eufemias gate 16, N-0191, Oslo, Norway.
| | - Haakon Hansen
- Norwegian Veterinary Institute, P.O. Box 750 Sentrum, , N-0106, Oslo, Norway.
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16
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Wessel Ø, Nyman IB, Markussen T, Dahle MK, Rimstad E. Piscine orthoreovirus (PRV) ơ3 protein binds dsRNA. Virus Res 2015; 198:22-9. [PMID: 25596495 DOI: 10.1016/j.virusres.2015.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 01/05/2015] [Accepted: 01/05/2015] [Indexed: 12/27/2022]
Abstract
Piscine orthoreovirus (PRV) has a double-stranded, segmented RNA genome and belongs to the family Reoviridae. PRV is associated with heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar L.) and cause intraerythrocytic inclusions. The virus is widespread in both wild and farmed salmonid fish in Europe, North- and South America. In mammalian orthoreovirus (MRV), the outer capsid protein ơ3 has dsRNA binding properties, which serve to inhibit the early innate immune response of the host. Important structural motifs and key amino acid residues are conserved between MRV ơ3 and the homologous PRV protein, and we hypothesized that PRV ơ3 binds dsRNA. Gene regions and amino acid residues predicted to be important for dsRNA binding were determined through bioinformatic analysis and investigated functionally following site-directed mutagenesis and the generation of truncated ơ3 variants. Our results provide evidence that the PRV protein ơ3 binds dsRNA in a sequence independent manner, thus sharing this function with MRV ơ3. Although no specific domain solely responsible for dsRNA binding was determined, the results point to residues within a predominantly basic region to be important for this functional property. We conclude that multiple sites are involved in the dsRNA binding activity of PRV ơ3.
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Affiliation(s)
- Øystein Wessel
- Department of Food Safety & Infection Biology, Norwegian University of Life Sciences, Oslo, Norway.
| | - Ingvild Berg Nyman
- Department of Food Safety & Infection Biology, Norwegian University of Life Sciences, Oslo, Norway.
| | | | | | - Espen Rimstad
- Department of Food Safety & Infection Biology, Norwegian University of Life Sciences, Oslo, Norway.
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17
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McBeath A, Aamelfot M, Christiansen DH, Matejusova I, Markussen T, Kaldhusdal M, Dale OB, Weli SC, Falk K. Immersion challenge with low and highly virulent infectious salmon anaemia virus reveals different pathogenesis in Atlantic salmon, Salmo salar L. J Fish Dis 2015; 38:3-15. [PMID: 24820820 DOI: 10.1111/jfd.12253] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 03/21/2014] [Accepted: 03/24/2014] [Indexed: 06/03/2023]
Abstract
The salmonid orthomyxovirus infectious salmon anaemia virus (ISAV) causes disease of varying severity in farmed Atlantic salmon, Salmo salar L. Field observations suggest that host factors, the environment and differences between ISAV strains attribute to the large variation in disease progression. Variation in host mortality and dissemination of ISAV isolates with high and low virulence (based on a previously published injection challenge) were investigated using immersion challenge. Virus dissemination was determined using real-time PCR and immunohistochemistry in several organs, including blood. Surprisingly, the low virulent virus (LVI) replicated and produced nucleoprotein at earlier time points post-infection compared to the virus of high virulence (HVI). This was particularly noticeable in the gills as indicated by different viral load profiles. However, the HVI reached a higher maximum viral load in all tested organs and full blood. This was associated with a higher mortality of 100% as compared to 20% in the LVI group by day 23 post-infection. Immersion challenge represented a more natural infection method and suggested that specific entry routes into the fish may be of key importance between ISAV strains. The results suggest that a difference in virulence is important for variations in virus dissemination and pathogenesis (disease development).
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Affiliation(s)
- A McBeath
- Marine Scotland Science, Marine Laboratory, Aberdeen, UK
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18
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McBeath AJA, Ho YM, Aamelfot M, Hall M, Christiansen DH, Markussen T, Falk K, Matejusova I. Low virulent infectious salmon anaemia virus (ISAV) replicates and initiates the immune response earlier than a highly virulent virus in Atlantic salmon gills. Vet Res 2014; 45:83. [PMID: 25143055 PMCID: PMC4144175 DOI: 10.1186/s13567-014-0083-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 07/24/2014] [Indexed: 01/12/2023] Open
Abstract
Observations from the field and experimental evidence suggest that different strains of infectious salmon anaemia virus (ISAV) can induce disease of varying severity in Atlantic salmon. Variation in host mortality and dissemination of ISAV isolates with high and low virulence was investigated using immersion challenge; from which mortality, pathological, immunohistochemical and preliminary molecular results have been previously published. Here, real-time RT-PCR analysis and statistical modelling have been used to further investigate variation in virus load and the response of four select immune genes. Expression of type I and II interferon (IFN), Mx and γIFN induced protein (γIP) to high and low pathogenic virus infection were examined in gill, heart and anterior kidney. In addition, a novel RNA species-specific assay targeting individual RNA types was used to investigate the separate viral processes of transcription and replication. Unexpectedly, the low virulent ISAV (LVI) replicated and transcribed more rapidly in the gills compared to the highly virulent virus (HVI). Subsequently LVI was able to disseminate to the internal organs more quickly and induced a more rapid systemic immune response in the host that may have offered some protection. Contrary to this, HVI initially progressed more slowly in the gills resulting in a slower generalised infection. However HVI ultimately reached a higher viral load and induced a greater mortality.
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Affiliation(s)
| | - Yee Mai Ho
- />Marine Scotland Science, Marine Laboratory, Aberdeen, Scotland UK
| | | | - Malcolm Hall
- />Marine Scotland Science, Marine Laboratory, Aberdeen, Scotland UK
| | | | | | - Knut Falk
- />Norwegian Veterinary Institute, Oslo, Norway
| | - Iveta Matejusova
- />Marine Scotland Science, Marine Laboratory, Aberdeen, Scotland UK
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19
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Markussen T, Sindre H, Jonassen CM, Tengs T, Kristoffersen AB, Ramsell J, Numanovic S, Hjortaas MJ, Christiansen DH, Dale OB, Falk K. Ultra-deep pyrosequencing of partial surface protein genes from infectious Salmon Anaemia virus (ISAV) suggest novel mechanisms involved in transition to virulence. PLoS One 2013; 8:e81571. [PMID: 24303056 PMCID: PMC3841194 DOI: 10.1371/journal.pone.0081571] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 10/14/2013] [Indexed: 11/22/2022] Open
Abstract
Uncultivable HPR0 strains of infectious salmon anaemia viruses (ISAVs) infecting gills are non-virulent putative precursors of virulent ISAVs (vISAVs) causing systemic disease in farmed Atlantic salmon (Salmo salar). The transition to virulence involves two molecular events, a deletion in the highly polymorphic region (HPR) of the hemagglutinin-esterase (HE) gene and a Q266→L266 substitution or insertion next to the putative cleavage site (R267) in the fusion protein (F). We have performed ultra-deep pyrosequencing (UDPS) of these gene regions from healthy fish positive for HPR0 virus carrying full-length HPR sampled in a screening program, and a vISAV strain from an ISA outbreak at the same farming site three weeks later, and compared the mutant spectra. As the UDPS data shows the presence of both HE genotypes at both sampling times, and the outbreak strain was unlikely to be directly related to the HPR0 strain, this is the first report of a double infection with HPR0s and vISAVs. For F amplicon reads, mutation frequencies generating L266 codons in screening samples and Q266 codons in outbreak samples were not higher than at any random site. We suggest quasispecies heterogeneity as well as RNA structural properties are linked to transition to virulence. More specifically, a mechanism where selected single point mutations in the full-length HPR alter the RNA structure facilitating single- or sequential deletions in this region is proposed. The data provides stronger support for the deletion hypothesis, as opposed to recombination, as the responsible mechanism for generating the sequence deletions in HE.
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Affiliation(s)
- Turhan Markussen
- Department of Laboratory Services, Norwegian Veterinary Institute, Oslo, Norway
- * E-mail:
| | - Hilde Sindre
- Department of Laboratory Services, Norwegian Veterinary Institute, Oslo, Norway
| | | | - Torstein Tengs
- Department of Laboratory Services, Norwegian Veterinary Institute, Oslo, Norway
| | | | - Jon Ramsell
- Department of Laboratory Services, Norwegian Veterinary Institute, Oslo, Norway
| | - Sanela Numanovic
- Department of Laboratory Services, Norwegian Veterinary Institute, Oslo, Norway
| | - Monika J. Hjortaas
- Department of Laboratory Services, Norwegian Veterinary Institute, Oslo, Norway
| | - Debes H. Christiansen
- National Reference Laboratory for Fish Diseases, Food and Veterinary Authority, Torshavn, Faroe Islands
| | - Ole Bendik Dale
- Department of Laboratory Services, Norwegian Veterinary Institute, Oslo, Norway
| | - Knut Falk
- Department of Health Surveillance, Norwegian Veterinary Institute, Oslo, Norway
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20
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Markussen T, Dahle MK, Tengs T, Løvoll M, Finstad ØW, Wiik-Nielsen CR, Grove S, Lauksund S, Robertsen B, Rimstad E. Sequence analysis of the genome of piscine orthoreovirus (PRV) associated with heart and skeletal muscle inflammation (HSMI) in Atlantic salmon (Salmo salar). PLoS One 2013; 8:e70075. [PMID: 23922911 PMCID: PMC3726481 DOI: 10.1371/journal.pone.0070075] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 06/16/2013] [Indexed: 12/20/2022] Open
Abstract
Piscine orthoreovirus (PRV) is associated with heart- and skeletal muscle inflammation (HSMI) of farmed Atlantic salmon (Salmo salar). We have performed detailed sequence analysis of the PRV genome with focus on putative encoded proteins, compared with prototype strains from mammalian (MRV T3D)- and avian orthoreoviruses (ARV-138), and aquareovirus (GCRV-873). Amino acid identities were low for most gene segments but detailed sequence analysis showed that many protein motifs or key amino acid residues known to be central to protein function are conserved for most PRV proteins. For M-class proteins this included a proline residue in μ2 which, for MRV, has been shown to play a key role in both the formation and structural organization of virus inclusion bodies, and affect interferon-β signaling and induction of myocarditis. Predicted structural similarities in the inner core-forming proteins λ1 and σ2 suggest a conserved core structure. In contrast, low amino acid identities in the predicted PRV surface proteins μ1, σ1 and σ3 suggested differences regarding cellular interactions between the reovirus genera. However, for σ1, amino acid residues central for MRV binding to sialic acids, and cleavage- and myristoylation sites in μ1 required for endosomal membrane penetration during infection are partially or wholly conserved in the homologous PRV proteins. In PRV σ3 the only conserved element found was a zinc finger motif. We provide evidence that the S1 segment encoding σ3 also encodes a 124 aa (p13) protein, which appears to be localized to intracellular Golgi-like structures. The S2 and L2 gene segments are also potentially polycistronic, predicted to encode a 71 aa- (p8) and a 98 aa (p11) protein, respectively. It is concluded that PRV has more properties in common with orthoreoviruses than with aquareoviruses.
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Affiliation(s)
- Turhan Markussen
- Department of Laboratory Services, National Veterinary Institute, Oslo, Norway
| | - Maria K. Dahle
- Department of Laboratory Services, National Veterinary Institute, Oslo, Norway
| | - Torstein Tengs
- Department of Laboratory Services, National Veterinary Institute, Oslo, Norway
| | - Marie Løvoll
- Department of Laboratory Services, National Veterinary Institute, Oslo, Norway
| | - Øystein W. Finstad
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, Oslo, Norway
| | | | - Søren Grove
- Department of Laboratory Services, National Veterinary Institute, Oslo, Norway
| | - Silje Lauksund
- Norwegian College of Fishery Science, University of Tromsø, Tromsø, Norway
| | - Børre Robertsen
- Norwegian College of Fishery Science, University of Tromsø, Tromsø, Norway
| | - Espen Rimstad
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, Oslo, Norway
- * E-mail:
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21
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Lyngstad TM, Hjortaas MJ, Kristoffersen AB, Markussen T, Karlsen ET, Jonassen CM, Jansen PA. Use of molecular epidemiology to trace transmission pathways for infectious salmon anaemia virus (ISAV) in Norwegian salmon farming. Epidemics 2010; 3:1-11. [PMID: 21420655 DOI: 10.1016/j.epidem.2010.11.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Revised: 11/02/2010] [Accepted: 11/10/2010] [Indexed: 10/18/2022] Open
Abstract
BACKGROUND Infectious Salmon Anaemia (ISA) is a disease affecting farmed Atlantic salmon, and most salmon producing countries have experienced ISA outbreaks. The aim of the present study was to use epidemiological and viral sequence information to trace transmission pathways for ISA virus (ISAV) in Norwegian salmon farming. METHODS The study covers a period from January 2007 to July 2009 with a relatively high rate of ISA outbreaks, including a large cluster of outbreaks that emerged in Northern Norway (the North-cluster). Farms with ISA outbreaks and neighbouring salmon farms (At-risk-sites) were tested for the presence of ISAV, and epidemiological information was collected. ISAV hemagglutinin-esterase (HE) and fusion (F) protein genes were sequenced and phylogenetic analyses were performed. Associations between sequence similarities and salmon population data were analysed to substantiate possible transmission pathways. RESULTS There was a high degree of genetic similarity between ISAV isolates within the North-cluster. ISAV was detected in 12 of 28 At-risk-sites, and a high proportion of the viruses were identified as putative low virulent genotypes harbouring the full length highly polymorphic region (HPR); HPR0 of the HE protein and the amino acid glutamine (Q) in the F protein at position 266. The sequences from HPR0/F (Q(266)) genotypes revealed larger genetic variation, lower viral loads and lower prevalence of infection than HPR-deleted genotypes. Seaway distance between salmon farms was the only robust explanatory variable to explain genetic similarity between ISAV isolates. DISCUSSION We suggest that a single HPR-deleted genotype of ISAV has spread between salmon farms in the North-cluster. Furthermore, we find that HPR0/F (Q(266)) genotypes are frequently present in farmed populations of Atlantic salmon. From this, we anticipate a population dynamics of ISAV portrayed by low virulent genotypes occasionally transitioning into virulent genotypes, causing solitary outbreaks or local epidemics through local transmission.
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22
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Müller A, Markussen T, Drabløs F, Gjøen T, Jørgensen TØ, Solem ST, Mjaaland S. Structural and functional analysis of the hemagglutinin-esterase of infectious salmon anaemia virus. Virus Res 2010; 151:131-41. [PMID: 20398710 PMCID: PMC7114507 DOI: 10.1016/j.virusres.2010.03.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2009] [Revised: 03/30/2010] [Accepted: 03/31/2010] [Indexed: 10/29/2022]
Abstract
Infectious salmon anaemia virus (ISAV) is a piscine orthomyxovirus causing a serious disease in farmed Atlantic salmon (Salmo salar L.). The virus surface glycoprotein hemagglutinin-esterase (HE) is responsible for both viral attachment and release. Similarity to bovine and porcine torovirus hemagglutinin-esterase (BToV HE, PToV HE), bovine coronavirus HE (BCoV HE) and influenza C hemagglutinin-esterase-fusion (InfC HEF) proteins were exploited in a computational homology-based structure analysis of ISAV HE. The analysis resolved structural aspects of the protein and identified important features of relevance to ISAV HE activity. By recombinant expression and purification of secretory HE (recHE) proteins, receptor-binding and quantitative analyses of enzymatic activities displayed by ISAV HE molecules are presented for the first time. Three different recHE molecules were constructed: one representing a high virulent isolate, one a low virulent, while in the third a Ser(32) to Ala(32) amino acid substitution was introduced in the enzymatic catalytic site as inferred from the model. The three amino acid differences between the high and low virulent variants, of which two localized to the putative receptor-binding domain and one in the esterase domain, had no impact on receptor-binding or -release activities. In contrast, the Ser(32) amino acid substitution totally abolished enzymatic activity while receptor binding increased, as observed by agglutination of Atlantic salmon red blood cells. This demonstrates the essential role of a serine in the enzyme's catalytic site. In conclusion, structural analysis of ISAV HE in combination with selected recHE proteins gave insights into structure-function relationships and opens up for further studies aiming at dissecting molecular determinants of ISAV virulence.
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Affiliation(s)
- Anita Müller
- Department of Marine Biotechnology, Norwegian College of Fishery Science, Breivika, N-9037 Tromsø, Norway
| | - Turhan Markussen
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, P.O. Box 8146 Dep., N-0033 Oslo, Norway
| | - Finn Drabløs
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, N-7006 Trondheim, Norway
| | - Tor Gjøen
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, N-0316 Oslo, Norway
| | - Trond Ø. Jørgensen
- Department of Marine Biotechnology, Norwegian College of Fishery Science, Breivika, N-9037 Tromsø, Norway
- Centre on Marine Bioactives and Drug Discovery (MabCent), University of Tromsø, N-9037 Tromsø, Norway
| | - Stein Tore Solem
- Department of Marine Biotechnology, Norwegian College of Fishery Science, Breivika, N-9037 Tromsø, Norway
| | - Siri Mjaaland
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, P.O. Box 8146 Dep., N-0033 Oslo, Norway
- Department of Bacteriology and Immunology, The Norwegian Institute of Public Health, P.O. Box 4404 Nydalen, N-0403 Oslo, Norway
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García-Rosado E, Markussen T, Kileng O, Baekkevold ES, Robertsen B, Mjaaland S, Rimstad E. Molecular and functional characterization of two infectious salmon anaemia virus (ISAV) proteins with type I interferon antagonizing activity. Virus Res 2008; 133:228-38. [PMID: 18304672 DOI: 10.1016/j.virusres.2008.01.008] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Revised: 01/11/2008] [Accepted: 01/12/2008] [Indexed: 12/25/2022]
Abstract
In this study we characterize two proteins encoded by the two smallest genomic segments of the piscine orthomyxovirus infectious salmon anaemia virus (ISAV). Both proteins, encoded by the un-spliced ORF from genomic segment 7 (s7ORF1) and the larger ORF from segment 8 (s8ORF2), are involved in modulation of the type I interferon (IFN) response. The data suggests that the s7ORF1 protein is collinearly encoded, non-structural, contains no nuclear localisation signals, localises mainly to the cytoplasmic perinuclear area and does not bind single- or double-stranded RNA. On the other hand, genomic segment 8 uses a bicistronic coding strategy and the encoded s8ORF2 protein is a structural component of the viral particle. This protein contains two nuclear localisation signals, has a predominantly nuclear localisation, binds both double-stranded RNA and poly-A tailed single-stranded RNA, but not double-stranded DNA. In poly I:C stimulated salmon cells both ISAV proteins independently down-regulate the type I IFN promoter activity. Thus, ISAV counteracts the type I IFN response by the action of at least two of its gene products, rather than just one, as appears to be the case for other known members of the Orthomyxoviridae.
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Affiliation(s)
- Esther García-Rosado
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, P.O. Box 8146 Dep., N-0033 Oslo, Norway.
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Markussen T, Jonassen CM, Numanovic S, Braaen S, Hjortaas M, Nilsen H, Mjaaland S. Evolutionary mechanisms involved in the virulence of infectious salmon anaemia virus (ISAV), a piscine orthomyxovirus. Virology 2008; 374:515-27. [PMID: 18280528 DOI: 10.1016/j.virol.2008.01.019] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2007] [Accepted: 01/04/2008] [Indexed: 11/25/2022]
Abstract
Infectious salmon anaemia virus (ISAV) is an orthomyxovirus causing a multisystemic, emerging disease in Atlantic salmon. Here we present, for the first time, detailed sequence analyses of the full-genome sequence of a presumed avirulent isolate displaying a full-length hemagglutinin-esterase (HE) gene (HPR0), and compare this with full-genome sequences of 11 Norwegian ISAV isolates from clinically diseased fish. These analyses revealed the presence of a virulence marker right upstream of the putative cleavage site R267 in the fusion (F) protein, suggesting a Q266-->L266 substitution to be a prerequisite for virulence. To gain virulence in isolates lacking this substitution, a sequence insertion near the cleavage site seems to be required. This strongly suggests the involvement of a protease recognition pattern at the cleavage site of the fusion protein as a determinant of virulence, as seen in highly pathogenic influenza A virus H5 or H7 and the paramyxovirus Newcastle disease virus.
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Affiliation(s)
- Turhan Markussen
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, P.O. Box 8146 Dep., N-0033 Oslo, Norway.
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25
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Mjaaland S, Markussen T, Sindre H, Kjøglum S, Dannevig BH, Larsen S, Grimholt U. Susceptibility and immune responses following experimental infection of MHC compatible Atlantic salmon (Salmo salar L.) with different infectious salmon anaemia virus isolates. Arch Virol 2005; 150:2195-216. [PMID: 16012784 DOI: 10.1007/s00705-005-0588-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Accepted: 05/13/2005] [Indexed: 10/25/2022]
Abstract
Infectious salmon anaemia virus (ISAV) is an aquatic orthomyxovirus causing a multisystemic disease in farmed Atlantic salmon (Salmo salar) where disease development, clinical signs, and histopathology vary to a large extent. Here, an experimental trial was designed to determine the effect of variation in viral genes on virus-host interactions, as measured by disease susceptibility and immune responses. The fish were infected using cohabitant transmission, representing a natural route of infection. Variation caused by host factors was minimized using MHC compatible A. salmon half-siblings as experimental fish. Virus isolates were selected according to HE genotype, as European ISAV isolates can be genotyped according to deletion patterns in their hemagglutinin-esterase (HE) surface glycoprotein, and the course of disease they typically induce, classified as acute versus protracted. The different ISAV isolates induced large variations in death prevalence, ranging from 0-47% in the test-group and 3-75% in the cohabitant fish. The use of MHC compatible experimental fish made it possible to determine the relative contribution of humoral versus cellular response in protection against ISA. Ability to induce a strong proliferative response correlated with survival and virus clearance, while induction of a humoral response was less protective.
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Affiliation(s)
- S Mjaaland
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, Oslo, Norway.
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26
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Acheré V, Faivre-Rampant P, Jeandroz S, Besnard G, Markussen T, Aragones A, Fladung M, Ritter E, Favre JM. A full saturated linkage map of Picea abies including AFLP, SSR, ESTP, 5S rDNA and morphological markers. Theor Appl Genet 2004; 108:1602-1613. [PMID: 14991106 DOI: 10.1007/s00122-004-1587-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2003] [Accepted: 12/19/2003] [Indexed: 05/24/2023]
Abstract
Based on an F(1) progeny of 73 individuals, two parental maps were constructed according to the double pseudo-test cross strategy. The paternal map contained 16 linkage groups for a total genetic length of 1,792 cM. The maternal map covered 1,920 cM, and consisted of 12 linkage groups. These parental maps were then integrated using 66 intercross markers. The resulting consensus map covered 2,035 cM and included 755 markers (661 AFLPs, 74 SSRs, 18 ESTPs, the 5S rDNA and the early cone formation trait) on 12 linkage groups, reflecting the haploid number of chromosomes of Picea abies. The average spacing between two adjacent markers was 2.6 cM. The presence of 39 of the SSR and/or ESTP markers from this consensus map on other published maps of different Picea and Pinus species allowed us to establish partial linkage group homologies across three P. abies maps (up to five common markers per linkage group). This first saturated linkage map of P. abies could be therefore used as a support for developing comparative genome mapping in conifers.
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Affiliation(s)
- V Acheré
- UMR INRA/UHP 1136, Tree-Microbe Interactions, Faculté des Sciences, Université Nancy I, BP 239, 54506 Vandoeuvre-lès-Nancy, France
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27
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Markussen T, Fu X, Margulies L, Lauridsen EM, Nielsen SF, Schmidt S, Poulsen HF. An algebraic algorithm for generation of three-dimensional grain maps based on diffraction with a wide beam of hard X-rays. J Appl Crystallogr 2004. [DOI: 10.1107/s0021889803024907] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
A reconstruction method is presented for generation of three-dimensional maps of the grain boundaries within powders or polycrystals. The grains are assumed to have a mosaic spread below 1°. They are mapped by diffraction with a wide beam of hard X-rays, using a setup similar to that of parallel-beam absorption contrast tomography. First the diffraction spots are sorted with respect to grain of origin. Next, for each grain the reconstruction is performed by an algebraic algorithm known as three-dimensional ART. From simulations it is found that reconstructions with a spatial accuracy better than the pixel size of the detector can be obtained from as few as five diffraction spots. The results are superior to three-dimensional reconstructions based on the same data using a variant of the filtered back-projection algorithm. In comparison with layer-by-layer type reconstructions based on the two-dimensional ART algorithm, as introduced by Poulsen & Fu [J. Appl. Cryst.(2003),36, 1062–1068], the quality of the maps is found to be similar, provided that five to ten spots are available for analysis, while data acquisition with the three-dimensional method is much faster. The three-dimensional ART methodology is validated on experimental data. With state-of-the-art detectors, the spatial accuracy is estimated to be 5 µm.
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