Tor Gjøen

• Velle, Gaute; Thorstad, Eva Bonsak; Garseth, Åse Helen; Gjøen, Tor; Gulla, Snorre & Lo, Håvard [Vis alle 8 forfattere av denne artikkelen] (2025). Balancing the restoration of a native fish and the risks of hitchhiking invasive species. Management of Biological Invasions. ISSN 1989-8649. 16(1), s. 247–276. doi: 10.3391/MBI.2025.16.1.15. Fulltekst i vitenarkiv Vis sammendrag

  Reintroducing a species to an area where it is locally extinct may contribute to reestablishing the ecosystem. However, we show that such reintroductions can pose a risk to biodiversity by introducing hitchhiking invasive organisms together with the donor population. This risk was caused by more severe impacts of invasive organisms in the habitat of the donor population than the receiving environment. The freshwater resident Atlantic salmon (Salmo salar) in Sweden’s River Klarälven perform feeding migrations to Lake Vänern. The upper part of the watershed, in Norway, lost its salmon population due to hydropower development that obstructed upstream migration. We conducted a risk assessment of the potential impacts on native ecosystems from invasive organisms associated with reintroducing Atlantic salmon into the Norwegian part of the watershed by importing adult salmon spawners. This assessment is crucial due to differences in the development of invasive organisms in the Swedish and Norwegian parts of the watershed. The risk of impacts was evaluated for invasive species, parasites, bacterial pathogens, and viruses that are present or likely present in the lower part of the watershed, or at risk of being introduced. We found a high risk of negative impacts associated with the parasite Gyrodactylus salaris, viral hemorrhagic septicemia virus (VHSV), Aphanomyces astaci causing crayfish plague, Renibacterium salmoninarum causing bacterial kidney disease, and Tetracapsuloides bryosalmonae causing proliferative kidney disease. In addition, 20 invasive species and pathogens were associated with a medium risk and three with a low risk. The case study contributes to a deeper understanding of how reestablishing locally extinct or diminished species can influence biodiversity conservation efforts and the health of aquatic ecosystems, underlining the importance of comprehensive planning in restoration projects. We highlight the importance of risk assessment of invasive species when considering the reintroduction of native species or dam removal. environmental risk assessment, non-native species, species reintroduction, pathogens, landlocked Atlantic salmon, biological conservation, dam removal

• Holmlund, Ingrid; Ahmadi, Samira; Ruyter, Bente Synnøve; Østbye, Tone-Kari K; Bou, Marta & Gjøen, Tor (2025). Effect of eicosapentaenoic acid on innate immune responses in Atlantic salmon cells infected with infectious salmon anemia virus. Virology Journal. 22(1), s. 1–15. doi: 10.1186/s12985-024-02619-0. Fulltekst i vitenarkiv Vis sammendrag

  Aquaculture is one of the world's fastest-growing sectors in food production but with multiple challenges related to animal handling and infections. The disease caused by infectious salmon anemia virus (ISAV) leads to outbreaks of local epidemics, reducing animal welfare, and causing significant economic losses. The composition of feed has shifted from marine ingredients such as fish oil and fish meal towards a more plant-based diet causing reduced levels of eicosapentaenoic acid (EPA). The aim of this study was to investigate whether low or high levels of EPA affect the expression of genes related to the innate immune response 48 h after infection with ISAV. The study includes seven experimental groups: ± ISAV and various levels of EPA up to 200 µM. Analysis of RNA sequencing data showed that more than 3000 genes were affected by ISAV alone (without additional EPA). In cells with increasing levels of EPA, more than 2500 additional genes were differentially expressed. This indicates that high levels of EPA concentration have an independent effect on gene expression in virus-infected cells, not observed at lower levels of EPA. Analyses of enriched biological processes and molecular functions (GO and KEGG analysis) revealed that EPA had a limited impact on the innate immune system alone, but that many processes were affected by EPA when cells were virus infected. Several biological pathways were affected, including protein synthesis (ribosomal transcripts), peroxisome proliferator activated receptor (PPAR) signaling, and ferroptosis. Cells exposed to both increasing concentrations of EPA and virus displayed gene expression patterns indicating increased formation of oxygen radicals and that cell death via ferroptosis was activated. This gene expression pattern was not observed during infection at low EPA levels or when Atlantic salmon kidney (ASK) cells were exposed to the highest EPA level (200 μM) without virus infection. Cell death via ferroptosis may therefore be a mechanism for controlled cell death and thus reduction of virus replication when there are enough polyunsaturated fatty acids (PUFAs) in the membrane.

• Gjøen, Tor; Ruyter, Bente Synnøve & Østbye, Tone-Kari K (2024). Effects of eicosapentaneoic acid on innate immune responses in an Atlantic salmon kidney cell line in vitro. PLOS ONE. 19(5). doi: 10.1371/journal.pone.0302286. Fulltekst i vitenarkiv Vis sammendrag

  Studies of the interplay between metabolism and immunity, known as immunometabolism, is steadily transforming immunological research into new understandings of how environmental cues like diet are affecting innate and adaptive immune responses. The aim of this study was to explore antiviral transcriptomic responses under various levels of polyunsaturated fatty acid. Atlantic salmon kidney cells (ASK cell line) were incubated for one week in different levels of the unsaturated n-3 eicosapentaneoic acid (EPA) resulting in cellular levels ranging from 2–20% of total fatty acid. These cells were then stimulated with the viral mimic and interferon inducer poly I:C (30 ug/ml) for 24 hours before total RNA was isolated and sequenced for transcriptomic analyses. Up to 200 uM EPA had no detrimental effects on cell viability and induced very few transcriptional changes in these cells. However, in combination with poly I:C, our results shows that the level of EPA in the cellular membranes exert profound dose dependent effects of the transcriptional profiles induced by this treatment. Metabolic pathways like autophagy, apelin and VEGF signaling were attenuated by EPA whereas transcripts related to fatty acid metabolism, ferroptosis and the PPAR signaling pathways were upregulated. These results suggests that innate antiviral responses are heavily influenced by the fatty acid profile of salmonid cells and constitute another example of the strong linkage between general metabolic pathways and inflammatory responses.

• Sahai-Hernandez, Pankaj; Pouget, Claire; Eyal, Shai; Svoboda, Ondrej; Chacon, Jose & Grimm, Lin [Vis alle 8 forfattere av denne artikkelen] (2023). Dermomyotome-derived endothelial cells migrate to the dorsal aorta to support hematopoietic stem cell emergence. eLIFE. 12. doi: 10.7554/eLife.58300. Fulltekst i vitenarkiv Vis sammendrag

  Development of the dorsal aorta is a key step in the establishment of the adult blood-forming system, since hematopoietic stem and progenitor cells (HSPCs) arise from ventral aortic endothelium in all vertebrate animals studied. Work in zebrafish has demonstrated that arterial and venous endothelial precursors arise from distinct subsets of lateral plate mesoderm. Here, we profile the transcriptome of the earliest detectable endothelial cells (ECs) during zebrafish embryogenesis to demonstrate that tissue-specific EC programs initiate much earlier than previously appreciated, by the end of gastrulation. Classic studies in the chick embryo showed that paraxial mesoderm generates a subset of somite-derived endothelial cells (SDECs) that incorporate into the dorsal aorta to replace HSPCs as they exit the aorta and enter circulation. We describe a conserved program in the zebrafish, where a rare population of endothelial precursors delaminates from the dermomyotome to incorporate exclusively into the developing dorsal aorta. Although SDECs lack hematopoietic potential, they act as a local niche to support the emergence of HSPCs from neighboring hemogenic endothelium. Thus, at least three subsets of ECs contribute to the developing dorsal aorta: vascular ECs, hemogenic ECs, and SDECs. Taken together, our findings indicate that the distinct spatial origins of endothelial precursors dictate different cellular potentials within the developing dorsal aorta.

• Bøe, Knut Egil; Grahek-Ogden, Danica; Hoel, Kristian; Gjøen, Tor; Godfroid, Jacques Xavier Leon & Janczak, Andrew Michael [Vis alle 11 forfattere av denne artikkelen] (2022). The use of light, restrictive feeding, fibrous feed and stocking density and the consequences for animal welfare for poultry species kept in Norway - Scientific Opinion of the Panel on Animal Health and Welfare of the Norwegian Scientific Committee for Food and Environment. VKM Report. 2022:24(24), s. 1–53. Fulltekst i vitenarkiv
• Thorstad, Eva Bonsak; Garseth, Åse Helen; Gjøen, Tor; Gulla, Snorre; Lo, Håvard & Malmstrøm, Martin [Vis alle 22 forfattere av denne artikkelen] (2021). Assessment of the risk of negative impact on biodiversity from import and release of eggs or live fish from landlocked Atlantic salmon from Klarälven in Sweden to Trysilelva in Norway. Scientific Opinion of the Panel on Alien Organisms and Trade in Endangered Species of the Norwegian Scientific Committee for Food and Environment. VKM Report. 2021(04). Fulltekst i vitenarkiv Vis sammendrag

  Introduction Atlantic salmon in the River Klarälven in Sweden live the entire life in freshwater, undertaking feeding migrations to Lake Vänern. The upper part of the watershed is in Norway and comprises the River Trysilelva and associated rivers and lakes. Atlantic salmon previously lived in the Norwegian part of the watershed but were lost due to the construction of 11 hydropower stations that block the upstream migration from Vänern. The power stations also cause a high mortality among downstream migrating fish. Tagging studies showed that there is 71-84% mortality of juveniles (smolts) and 100% mortality of adults during downstream migration past the eight lowermost power stations. Extensive mitigation measures are needed to reduce the mortality of downstream migrants and reestablish a population that can reach areas in Norway naturally without being captured in Sweden and transported to Norway. In 2015, the total costs of establishing fishways bypassing the power stations and securing safe downstream migration was estimated to be 1000 million SEK. To compensate for a decline of salmon due to lost habitat, hatchery-produced juveniles have been released in the watershed for more than 100 years, and adult salmon have been captured in the lower reaches of Klarälven and released in upstream reaches. After the Höljes power station was built, 80% of the salmon transported upstream were released upstream of Höljes. In 1993, the Norwegian government stopped these releases due to the large mortality of downstream migrating fish at the power stations. The releases had already been stopped from late summer 1988 due to bacterial kidney disease (BKD) outbreaks in salmon populations in the watershed. Since 1988, transported fish have been released upstream of Edsforsen in Sweden, and have not been able to reach Norway. Aim of report The Norwegian Environment Agency asked VKM to carry out a risk assessment of three specified methods that can be used to reestablish salmon in the Norwegian part of the watershed. This risk assessment is pertinent because the occurrence of alien organisms and infectious agents have developed differently in the Swedish and Norwegian parts of the watershed after salmon became unable to migrate through the river system. In 2013, the fish parasite Gyrodactylus salaris was detected in Klarälven, but has not been recorded in Norwegian parts of the watershed. Here, we assess the risk of negative impacts on native biodiversity by importing Atlantic salmon eggs or live adults from Klarälven to Norway. Three methods of importing eggs or adults were assessed: I. Import of fertilised eggs to a local hatchery in Norway, which are planted in the river in the spring or hatched and released as juveniles or smolts. II. Import of fertilised eggs that will be used to establish a long-term broodstock in Norway using the gene bank model, from which eggs can be planted into the river, or transferred to a local hatchery with subsequent release of juveniles or smolts. III. Import of adult salmon spawners that are captured in the lower parts of Klarälven in Sweden, transported in tanks and released in the Norwegian parts of the watershed. Methods The risk assessment was based on a literature review and qualitative assessment of each of the three methods of importing eggs or adults. The risk of impacts on native biodiversity and ecosystems was assessed for infectious agents, including parasites, bacterial pathogens, and viruses, and for other alien species. For each of the infectious agents and alien species, the risk is based on the product of the magnitude of the potential negative impact to native biodiversity and ecosystems, and the likelihood that negative consequences occur. The risk assessment concludes in terms of low, moderate, or high risk. .......................

• Andresen, Adriana Magalhães Santos & Gjøen, Tor (2021). Chitosan nanoparticle formulation attenuates poly (I:C) induced innate immune responses against inactivated virus vaccine in Atlantic salmon (Salmo salar). Comparative Biochemistry and Physiology - Part D:Genomics and Proteomics. ISSN 1744-117X. 40. doi: 10.1016/j.cbd.2021.100915. Fulltekst i vitenarkiv
• Nilsen, Erlend Birkeland; Austrheim, Gunnar; Gjøen, Tor; Kvie, Kjersti Sternang; Malmstrøm, Martin & Ytrehus, Bjørnar [Vis alle 15 forfattere av denne artikkelen] (2021). Assessment of the risk to Norwegian biodiversity from import and keeping of American bison, European bison, domesticated water buffalo and domesticated yak. Scientific Opinion of the panel on Alien Organisms and Trade in Endangered Species (CITES) of the Norwegian Scientific Committee for Food and Environment. VKM Report. 2021(20), s. 1–77. Fulltekst i vitenarkiv
• Samuelsen, Ørjan; Åstrand, Ove Alexander Høgmoen; Frøhlich, Christopher; Heikal, Adam; Skagseth, Susann & Carlsen, Trine Josefine Olsen [Vis alle 17 forfattere av denne artikkelen] (2020). ZN148 Is a Modular Synthetic Metallo-beta-Lactamase Inhibitor That Reverses Carbapenem Resistance in Gram-Negative Pathogens In Vivo. Antimicrobial Agents and Chemotherapy. ISSN 0066-4804. 64(6). doi: 10.1128/AAC.02415-19. Fulltekst i vitenarkiv Vis sammendrag

  Carbapenem-resistant Gram-negative pathogens are a critical public health threat and there is an urgent need for new treatments. Carbapenemases (β-lactamases able to inactivate carbapenems) have been identified in both serine β-lactamase (SBL) and metallo-β-lactamase (MBL) families. The recent introduction of SBL carbapenemase inhibitors has provided alternative therapeutic options. Unfortunately, there are no approved inhibitors of MBL-mediated carbapenem-resistance and treatment options for infections caused by MBL-producing Gram-negatives are limited. Here, we present ZN148, a zinc-chelating MBL-inhibitor capable of restoring the bactericidal effect of meropenem and <i>in vitro</i> clinical susceptibility to carbapenems in >98% of a large international collection of MBL-producing clinical <i>Enterobacterales</i> strains (<i>n</i> = 234). Moreover, ZN148 was able to potentiate the effect of meropenem against NDM-1-producing <i>Klebsiella pneumoniae</i> in a murine neutropenic peritonitis model. ZN148 showed no inhibition of the human zinc-containing enzyme glyoxylase II at 500 μM, and no acute toxicity was observed in an <i>in vivo</i> mouse model with cumulative dosages up to 128 mg/kg. Biochemical analysis showed a time-dependent inhibition of MBLs by ZN148 and removal of zinc ions from the active site. Addition of exogenous zinc after ZN148 exposure only restored MBL activity by ∼30%, suggesting an irreversible mechanism of inhibition. Mass-spectrometry and molecular modeling indicated potential oxidation of the active site Cys221 residue. Overall, these results demonstrate the therapeutic potential of a ZN148-carbapenem combination against MBL-producing Gram-negative pathogens and that ZN148 is a highly promising MBL inhibitor that is capable of operating in a functional space not presently filled by any clinically approved compound.

• Andresen, Adriana Magalhaes Santos; Boudinot, Pierre & Gjøen, Tor (2020). Kinetics of transcriptional response against poly (I:C) and infectious salmon anemia virus (ISAV) in Atlantic salmon kidney (ASK) cell line. Developmental and Comparative Immunology. ISSN 0145-305X. 110. doi: 10.1016/j.dci.2020.103716. Fulltekst i vitenarkiv
• Andresen, Adriana Magalhaes Santos; Royo, Esmail Lutfi; Ruyter, Bente; Berge, Gerd Marit & Gjøen, Tor (2019). Interaction between dietary fatty acids and genotype on immune response in Atlantic salmon (Salmo salar) after vaccination: A transcriptome study. PLOS ONE. 14(7), s. 1–23. doi: 10.1371/journal.pone.0219625. Fulltekst i vitenarkiv Vis sammendrag

  A pivotal matter to aquaculture is the sourcing of sustainable resources as ingredients to aquafeeds. Levels of plant delivered oils as source of fatty acids (FA) in aquafeeds have reached around 70% resulting in reduced levels of long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in salmon fillet composition. EPA and DHA can modulate inflammation and immune response, so it is crucial to understand how fish immune response is affected by low LC n-3 PUFA diet and if this diet can have a detrimental effect on vaccine response. Atlantic salmon (Salmo salar) can produce EPA/DHA from α-linolenic acid (ALA) and this endogenous capacity can be explored to develop families with higher tolerance to low LC n-3 PUFA diets. Here we analyze innate and adaptive immune response in Atlantic salmon to a commercial vaccine after being fed low levels of EPA and DHA, and we also compare three strains of salmon selected by their endogenous capacity of synthesizing LC- n-3 PUFA. A total of 2,890 differentially expressed genes (DEGs) were identified (p-value adjusted < 0.1) when comparing vaccinated fish against control non-vaccinated. Gene ontology (GO) and KEGG analysis with 442 up/downregulated genes revealed that most DEGs were both related to immune response as well as part of important immune related pathways, as “Toll-like receptor” and “Cytokine-Cytokine interaction”. Adaptive response was also addressed by measuring antigen specific IgM, and titers were significantly higher than in the pre-immune fish at 62 days post-immunization. However, diet and strain had no/little effect on vaccine-specific IgM or innate immune responses. Atlantic salmon therefore display robustness in its response to vaccination even when feed low levels of LC n-3 PUFA.

• Kildahl-Andersen, Geir; Schnaars, Christian; Prandina, Anthony; Radix, Sylvie; Borgne, Marc Le & Jordheim, Lars Petter [Vis alle 13 forfattere av denne artikkelen] (2019). Synthesis and biological evaluation of zinc chelating compounds as metallo-β-lactamase inhibitors. MedChemComm. ISSN 2040-2503. 10(4), s. 528–537. doi: 10.1039/c8md00578h. Fulltekst i vitenarkiv
• Schnaars, Christian; kildahl-Andersen, Geir; Prandina, Anthony; Popal, Roya; Radix, Sylvie & Borgne, Marc Le [Vis alle 16 forfattere av denne artikkelen] (2018). Synthesis and preclinical evaluation of TPA-based zinc chelators as metallo-β-lactamase inhibitors. ACS Infectious Diseases. 4(9), s. 1407–1422. doi: 10.1021/acsinfecdis.8b00137. Fulltekst i vitenarkiv
• Pöthig, Alexander; Sara, Ahmed; Winther-Larsen, Hanne Cecilie; Guan, Shengyang; Altmann, Philipp J. & Kundermann, Jürgen [Vis alle 9 forfattere av denne artikkelen] (2018). Antimicrobial Activity and Cytotoxicity of Ag(I) and Au(I) Pillarplexes. Frontiers in Chemistry. 6. doi: 10.3389/fchem.2018.00584. Fulltekst i vitenarkiv
• Arnemo, Marianne; Kavaliauskis, Arturas; Andresen, Adriana Magalhaes Santos; Bou, Marta; Berge, Gerd Marit & Ruyter, Bente [Vis alle 7 forfattere av denne artikkelen] (2017). Effects of dietary n-3 fatty acids on Toll-like receptor activation in primary leucocytes from Atlantic salmon (Salmo salar). Fish Physiology & Biochemistry. ISSN 0920-1742. 43, s. 1065–1080. doi: 10.1007/s10695-017-0353-4. Fulltekst i vitenarkiv Vis sammendrag

  The shortage of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the international markets has led to increasing substitution of fish oil by plant oils in Atlantic salmon (Salmo salar) feed and thereby reducing the EPA and DHA content in salmon. However, the minimum required levels of these fatty acids in fish diets for securing fish health are unknown. Fish were fed with 0, 1 or 2% EPA or DHA alone or in combination of both over a period, growing from 50 to 400 g. Primary head kidney leucocytes were isolated and stimulated with Toll-like receptor (TLR) ligands to determine if EPA and DHA deficiency can affect expression of important immune genes and eicosanoid production. Several genes related to viral immune response did not vary between groups. However, there was a tendency that the high-level EPA and DHA groups expressed lower levels of IL-1β in non-stimulated leucocytes. These leucocytes were also more responsive to the TLR ligands, inducing higher expression levels of IL-1β and Mx1 after stimulation. The levels of prostaglandin E2 and leukotriene B4 in serum and media from stimulated leucocytes were lower in both low and high EPA and DHA groups. In conclusion, leucocytes from low EPA and DHA groups seemed to be less responsive towards immunostimulants, like TLR ligands, indicating that low levels or absence of dietary EPA and DHA may have immunosuppressive effects.

• Yazdani, Mazyar; Andresen, Adriana Magalhaes Santos & Gjøen, Tor (2016). Short-term effect of bisphenol-a on oxidative stress responses in Atlantic salmon kidney cell line: a transcriptional study. Toxicology Mechanisms and Methods. ISSN 1537-6516. 26(4), s. 295–300. doi: 10.1080/15376516.2016.1177864. Fulltekst i vitenarkiv
• Griffiths, Gareth Wyn; Müller, Ferenc; Ledin, Johan; Patton, E. Elizabeth; Gjøen, Tor & Lobert, Viola [Vis alle 12 forfattere av denne artikkelen] (2016). Fish from Head to Tail: The 9th European Zebrafish Meeting in Oslo. Zebrafish. ISSN 1545-8547. doi: 10.1089/zeb.2015.1212. Fulltekst i vitenarkiv
• Arnemo, Marianne; Watle, Sara Sofie Viksmoen; Schoultz, Kristin Merete; Vainio, Kirsti; Norheim, Gunnstein & Moorthy, Vasee [Vis alle 9 forfattere av denne artikkelen] (2016). Stability of a Vesicular Stomatitis Virus-Vectored Ebola Vaccine. Journal of Infectious Diseases. ISSN 0022-1899. 213(6), s. 930–933. doi: 10.1093/infdis/jiv532. Fulltekst i vitenarkiv
• Kavaliauskis, Arturas; Arnemo, Marianne; Rishovd, Anne-Lise & Gjøen, Tor (2016). Activation of unfolded protein response pathway during infectious salmon anemia virus (ISAV) infection in vitro an in vivo. Developmental and Comparative Immunology. ISSN 0145-305X. 54(1), s. 46–54. doi: 10.1016/j.dci.2015.08.009. Fulltekst i vitenarkiv
• Brietzke, Andreas; Arnemo, Marianne; Gjøen, Tor; Rebl, Henrike; Korytár, Tomás & Goldammer, Tom [Vis alle 8 forfattere av denne artikkelen] (2016). Structurally diverse genes encode Tlr2 in rainbow trout: The conserved receptor cannot be stimulated by classical ligands to activate NF-κB in vitro. Developmental and Comparative Immunology. ISSN 0145-305X. 54(1), s. 75–88. doi: 10.1016/j.dci.2015.08.012. Fulltekst i vitenarkiv
• Kavaliauskis, Arturas; Arnemo, Marianne; Speth, Martin; Lagos, Leidy; Rishovd, Anne-Lise & Estepa, Amparo [Vis alle 8 forfattere av denne artikkelen] (2016). Protective effect of a recombinant VHSV-G vaccine using poly(I: C) loaded nanoparticles as an adjuvant in zebrafish (Danio rerio) infection model. Developmental and Comparative Immunology. ISSN 0145-305X. 61, s. 248–257. doi: 10.1016/j.dci.2016.04.010. Fulltekst i vitenarkiv
• Kavaliauskis, Arturas; Arnemo, Marianne; Sung-Hyun, Kim; Ulanova, Lilia; Speth, Martin & Novoa, Beatriz [Vis alle 10 forfattere av denne artikkelen] (2015). Use of poly(I:C) stabilized with chitosan as a vaccine-adjuvant against viral hemorrhagic septicemia virus infection in zebrafish. Zebrafish. ISSN 1545-8547. 12(6), s. 421–431. doi: 10.1089/zeb.2015.1126. Fulltekst i vitenarkiv
• Yazdani, Mazyar; Paulsen, Ragnhild Elisabeth; Gjøen, Tor & Hylland, Ketil (2015). Reactive Oxygen Species and Cytotoxicity in Rainbow Trout Hepatocytes: Effects of Medium and Incubation Time. Bulletin of Environmental Contamination and Toxicology. ISSN 0007-4861. 94, s. 193–198. doi: 10.1007/s00128-014-1433-0. Fulltekst i vitenarkiv
• Kjær, Marte Avranden; Aursnes, Ingrid Augusta Stølen; Berge, Gerd Marit; Sørensen, Mette; Marchenko, Yuriy & Gjøen, Tor [Vis alle 7 forfattere av denne artikkelen] (2014). The influence of different dietary oil qualities on growth rate, feed utilization and oxidative stress in Atlantic cod. Aquaculture Nutrition. ISSN 1353-5773. 20(2), s. 192–204. doi: 10.1111/anu.12065. Fulltekst i vitenarkiv
• Ingebrigtsen, Ingrid Augusta Aursnes; Berge, Gerd Marit; Ruyter, Bente; Kjær, Marte Avranden; Mørkøre, Turid & Sørensen, Mette [Vis alle 7 forfattere av denne artikkelen] (2014). Growth and quality of Atlantic cod (Gadus morhua) fed with high and low fat diets supplemented with glutamate. Aquaculture. ISSN 0044-8486. 433, s. 367–376. doi: 10.1016/j.aquaculture.2014.06.036. Fulltekst i vitenarkiv
• Arnemo, Marianne; Kavaliauskis, Arturas & Gjøen, Tor (2014). Effects of TLR agonists and viral infection on cytokine and TLR expression in Atlantic salmon (Salmo salar). Developmental and Comparative Immunology. ISSN 0145-305X. 46(2), s. 139–145. doi: 10.1016/j.dci.2014.03.023. Fulltekst i vitenarkiv
• Schiøtz, Berit Lyng; Rosado, Esther G; Bækkevold, Espen Sønderaal; Lukacs, Morten; Mjaaland, Siri & Sindre, Hilde [Vis alle 8 forfattere av denne artikkelen] (2011). Enhanced transfection of cell lines from Atlantic salmon through nucoleofection and antibiotic selection. BMC Research Notes. 4. doi: 10.1186/1756-0500-4-136. Fulltekst i vitenarkiv Vis sammendrag

  Background Cell lines from Atlantic salmon kidney have made it possible to culture and study infectious salmon anemia virus (ISAV), an aquatic orthomyxovirus affecting farmed Atlantic salmon. However, transfection of these cells using calcium phosphate precipitation or lipid-based reagents shows very low transfection efficiency. The Amaxa Nucleofector technology™ is an electroporation technique that has been shown to be efficient for gene transfer into primary cells and hard to transfect cell lines. Findings Here we demonstrate, enhanced transfection of the head kidney cell line, TO, from Atlantic salmon using nucleofection and subsequent flow cytometry. Depending on the plasmid promoter, TO cells could be transfected transiently with an efficiency ranging from 11.6% to 90.8% with good viability, using Amaxa's cell line nucleofector solution T and program T-20. A kill curve was performed to investigate the most potent antibiotic for selection of transformed cells, and we found that blasticidin and puromycin were the most efficient for selection of TO cells. Conclusions The results show that nucleofection is an efficient way of gene transfer into Atlantic salmon cells and that stably transfected cells can be selected with blasticidin or puromycin.

• Trattner, S.; Ruyter, Bente; Østbye, Tone-Kari K; Kamal-Eldin, A.; Moazzami, A. & Pan, J. [Vis alle 10 forfattere av denne artikkelen] (2011). Influence of Dietary Sesamin, a Bioactive Compound on Fatty Acids and Expression of Some Lipid Regulating Genes in Baltic Atlantic Salmon (Salmo salar L.) Juveniles. Physiological Research. ISSN 0862-8408. 60(1), s. 125–137. doi: 10.33549/physiolres.932068. Fulltekst i vitenarkiv
• Aursnes, Ingrid Augusta Stølen; Rishovd, Anne-Lise; Karlsen, Hans Erik & Gjøen, Tor (2011). Validation of reference genes for quantitative RT-qPCR studies of gene expression in Atlantic cod (Gadus morhua I.) during temperature stress. BMC Research Notes. 4. doi: 10.1186/1756-0500-4-104. Fulltekst i vitenarkiv Vis sammendrag

  Background One important physiological response to environmental stress in animals is change in gene expression. To obtain reliable data from gene expression studies using RT-qPCR it is important to evaluate a set of possible reference genes as normalizers for expression. The expression of these candidate genes should be analyzed in the relevant tissues during normal and stressed situations. To find suitable reference genes it was crucial that the genes were stably expressed also during a situation of physiological stress. For poikilotermic animals like cod, changes in temperature are normal, but if the changes are faster than physiological compensation, the animals respond with typical stress responses. It has previously been shown that Atlantic cod show stress responses when elevation of water temperature is faster than 1 degree/day, for this reason we chose hyperthermia as stress agent for this experiment. Findings We here describe the expression of eight candidate reference genes from Atlantic cod (Gadus morhua l.) and their stability during thermal stress (temperature elevation of one degree C/day for 5 days). The genes investigated were: Eukaryotic elongation factor 1 alpha, ef1a; 18s ribosomal RNA; 18s, Ubiquitin conjugate protein; ubiq, cytoskeletal beta-actin; actb, major histcompatibility complex I; MHC-I light chain, beta-2 -microglobulin; b2m, cytoskeletal alpha-tubulin; tba1c, acidic ribosomal phosphoprotein; rplp1, glucose-6-phosphate dehydrogenase; g6pd. Their expression were analyzed in 6 tissues (liver, head kidney, intestine, spleen, heart and gills) from cods exposed to elevated temperature and compared to a control group. Although there were variations between tissues with respect to reference gene stability, four transcripts were more consistent than the others: ubiq, ef1a, 18s and rplp1. We therefore used these to analyze the expression of stress related genes (heat shock proteins) induced during hyperthermia. We found that both transcripts were significantly upregulated in several tissues in fish exposed to increased temperature. Conclusion This is the first study comparing reference genes for RT-qPCR analyses of expression during hyperthermia in Atlantic cod. ef1a, 18s, rplp1 and ubiq transcripts were found to be well suited as reference genes during these experimental conditions.

• Star, Bastiaan; Nederbragt, Alexander Johan; Jentoft, Sissel; Grimholt, Unni; Malmstrøm, Martin & Gregers, Tone Fredsvik [Vis alle 42 forfattere av denne artikkelen] (2011). The genome sequence of Atlantic cod reveals a unique immune system. Nature. ISSN 0028-0836. 477(7363), s. 207–210. doi: 10.1038/nature10342. Fulltekst i vitenarkiv Vis sammendrag

  Atlantic cod (Gadus morhua) is a large, cold-adapted teleost that sustains long-standing commercial fisheries and incipient aquaculture. Here we present the genome sequence of Atlantic cod, showing evidence for complex thermal adaptations in its haemoglobin gene cluster and an unusual immune architecture compared to other sequenced vertebrates. The genome assembly was obtained exclusively by 454 sequencing of shotgun and paired-end libraries, and automated annotation identified 22,154 genes. The major histocompatibility complex (MHC) II is a conserved feature of the adaptive immune system of jawed vertebrates, but we show that Atlantic cod has lost the genes for MHC II, CD4 and invariant chain (Ii) that are essential for the function of this pathway. Nevertheless, Atlantic cod is not exceptionally susceptible to disease under natural conditions5. We find a highly expanded number of MHC I genes and a unique composition of its Toll-like receptor (TLR) families. This indicates how the Atlantic cod immune system has evolved compensatory mechanisms in both adaptive and innate immunity in the absence of MHC II. These observations affect fundamental assumptions about the evolution of the adaptive immune system and its components in vertebrates.

• Muller, Anita; Markussen, Turhan; Drabløs, Finn; Gjøen, Tor; Jørgensen, Trond Ø. & Solem, Stein Tore [Vis alle 7 forfattere av denne artikkelen] (2010). Structural and functional analysis of the hemagglutinin-esterase of infectious salmon anaemia virus. Virus Research. ISSN 0168-1702. 151(2), s. 131–141. doi: 10.1016/j.virusres.2010.03.020. Fulltekst i vitenarkiv
• Hetland, Dyveke; Jørgensen, Sven Martin; Skjødt, Karsten; Dale, Ole Bendik; Falk, Knut & Xu, Cheng [Vis alle 10 forfattere av denne artikkelen] (2010). In situ localisation of major histocompatibility complex class I and class II and CD8 positive cells in infectious salmon anaemia virus (ISAV)-infected Atlantic salmon. Fish and Shellfish Immunology. ISSN 1050-4648. 28(1), s. 30–39. doi: 10.1016/j.fsi.2009.09.011. Fulltekst i vitenarkiv
• Schiøtz, Berit Lyng; Roos, Norbert; Rishovd, Anne-Lise & Gjøen, Tor (2010). Formation of autophagosomes and redistribution of LC3 upon in vitro infection with infectious salmon anemia virus. Virus Research. ISSN 0168-1702. 151(1), s. 104–107. doi: 10.1016/j.virusres.2010.03.013. Fulltekst i vitenarkiv
• Schiøtz, Berit Lyng; Bækkevold, Espen Sønderaal; Poulsen, Lene Cecilie; Mjaaland, S & Gjøen, Tor (2009). Analysis of host- and strain-dependent cell death responses during infectious salmon anemia virus infection in vitro. Virology Journal. 6. doi: 10.1186/1743-422X-6-91. Fulltekst i vitenarkiv Vis sammendrag

  Background Infectious salmon anemia virus (ISAV) is an aquatic orthomyxovirus and the causative agent of infectious salmon anemia (ISA), a disease of great importance in the Atlantic salmon farming industry. In vitro, ISAV infection causes cytophatic effect (CPE) in cell lines from Atlantic salmon, leading to rounding and finally detachment of the cells from the substratum. In this study, we investigated the mode of cell death during in vitro ISAV infection in different Atlantic salmon cell lines, using four ISAV strains causing different mortality in vivo. Results The results show that caspase 3/7 activity increased during the course of infection in ASK and SHK-1 cells, infected cells showed increased surface expression of phosphatidylserine and increased PI uptake, compared to mock infected cells; and morphological alterations of the mitochondria were observed. Expression analysis of immune relevant genes revealed no correlation between in vivo mortality and expression, but good correlation in expression of interferon genes. Conclusion Results from this study indicate that there is both strain and cell type dependent differences in the virus-host interaction during ISAV infection. This is important to bear in mind when extrapolating in vitro findings to the in vivo situation.

• Schiøtz, Berit L.; Bækkevold, Espen S; Poulsen, Lene C.; Mjaaland, Siri & Gjøen, Tor (2009). Analysis of host- and strain-dependent cell death responses during infectious salmon anemia virus infection in vitro. Virology Journal. 6, s. 91–91. Fulltekst i vitenarkiv Vis sammendrag

  Background: Infectious salmon anemia virus (ISAV) is an aquatic orthomyxovirus and the causative agent of infectious salmon anemia (ISA), a disease of great importance in the Atlantic salmon farming industry. In vitro, ISAV infection causes cytophatic effect (CPE) in cell lines from Atlantic salmon, leading to rounding and finally detachment of the cells from the substratum. In this study, we investigated the mode of cell death during in vitro ISAV infection in different Atlantic salmon cell lines, using four ISAV strains causing different mortality in vivo. Results: The results show that caspase 3/7 activity increased during the course of infection in ASK and SHK-1 cells, infected cells showed increased surface expression of phosphatidylserine and increased PI uptake, compared to mock infected cells; and morphological alterations of the mitochondria were observed. Expression analysis of immune relevant genes revealed no correlation between in vivo mortality and expression, but good correlation in expression of interferon genes. Conclusion: Results from this study indicate that there is both strain and cell type dependent differences in the virus-host interaction during ISAV infection. This is important to bear in mind when extrapolating in vitro findings to the in vivo situation

• Ørpetveit, I; Gjøen, Tor; Sindre, Hilde & Dannevig, Birgit (2008). Binding of infectious pancreatic necrosis virus (IPNV) to membrane proteins from different fish cell lines. Archives of Virology. ISSN 0304-8608. 153. doi: 10.1007/s00705-007-0018-1. Fulltekst i vitenarkiv
• Kjær, Marte Avranden; Vegusdal, Anne; Gjøen, Tor; Rustan, Arild; Todorevic, M & Ruyter, B (2008). Effect of rapeseed oil and dietary n-3 fatty acids on triacylglycerol synthesis and secretion in Atlantic salmon hepatocytes. Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids. ISSN 1388-1981. 1781. doi: 10.1016/j.bbalip.2007.12.004. Fulltekst i vitenarkiv
• Kjær, Marte Avranden; Vegusdal, Anne; Gjøen, Tor; Rustan, Arild; Todorcevic, Marijana & Ruyter, Bente (2008). Effect of rapeseed oil and dietary n-3 fatty acids on triacylglycerol synthesis and secretion in Atlantic salmon hepatocytes. Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids. ISSN 1388-1981. 1781(3), s. 112–122. doi: 10.1016/j.bbalip.2007.12.004. Fulltekst i vitenarkiv Vis sammendrag

  Fish oil (FO) has traditionally been used as the dominating lipid component in fish feed. However, FO is a limited resource and the price varies considerably, which has led to an interest in using alternative oils, such as vegetable oils (VOs), in fish diets. It is far from clear how these VOs affect liver lipid secretion and fish health. The polyunsaturated fatty acids (PUFAs), eicosapentanoic acid (EPA) and docosahexanioc acid (DHA), reduce the secretion of lipoproteins rich in triacylglycerols (TAGs) in Atlantic salmon, as they do in humans. The mechanism by which n-3 fatty acids (FAs) in the diet reduce TAG secretion is not known. We have therefore investigated the effects of rapeseed oil (RO) and n-3 rich diets on the accumulation and secretion of H-3-glycerolipids by salmon hepatocytes. Salmon, of approximately 90 g were fed for 17 weeks on one of four diets supplemented with either 13.5% FO, RO, EPA-enriched oil or DHA-enriched oil until a final average weight of 310 g. Our results show that the dietary FA composition markedly influences the endogenous FA composition and lipid content of the hepatocytes. The intracellular lipid level in hepatocytes from fish fed RO diet and DHA diet were higher, and the expressions of the genes for microsomal transfer protein (MTP) and apolipoprotein A1 (Apo A1) were lower, than those in fish fed the two other diets. Secretion of hepatocyte glycerolipids was lower in fish fed the EPA diet and DHA diet than it was in fish fed the RO diet. Our results indicate that EPA and DHA possess different hypolipidemic properties. Both EPA and DHA inhibit TAG synthesis and secretion, but only EPA induces mitochondrial proliferation and reduce intracellular lipid. Expression of the gene for peroxisome proliferator-activated receptor alpha (PPAR alpha) was higher in the DHA dietary group than it was in the other groups. (C) 2008 Elsevier B.V. All rights reserved.

• Todorcevic, Marijana; Vegusdal, Anne; Gjøen, Tor; Sundvold, Hilde; Torstensen, Bente & Kjær, Marte Avranden [Vis alle 7 forfattere av denne artikkelen] (2008). Changes in fatty acids metabolism during differentiation of Atlantic salmon preadipocytes; Effects of n-3 and n-9 fatty acids. Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids. ISSN 1388-1981. 1781(6-7), s. 326–335. doi: 10.1016/j.bbalip.2008.04.014. Fulltekst i vitenarkiv Vis sammendrag

  Atlantic salmon (Salmo salar) preadipocytes, isolated from visceral adipose tissue, differentiate from an unspecialized fibroblast like cell type to mature adipocytes filled with lipid droplets in culture. The expression of the adipogenic gene markers peroxisome proliferated activated receptor (PPAR) alpha, lipoprotein lipase (LPL), microsomal triglyceride transfer protein (MTP), fatty acid transport protein (FATP) 1 and fatty acid binding protein (FABP) 3 increased during differentiation. In addition, we describe a novel alternatively spliced form of PPAR gamma (PPAR gamma short), the expression of which increased during differentiation. Eicosapentaenoic acid (20:5n-3, EPA) and docosahexaenoic acid (22:6n-3, DHA) lowered the triacylglycerol (TAG) accumulation in mature salmon adipocytes compared to oleic acid (18:1n-9, OA). This finding indicates that a reduced level of highly unsaturated n-3 fatty acids (HUFAs) in fish diets, when the traditional marine oil is exchanged for n-9 fatty acids (FAs) rich vegetable oils (VOs), may influence visceral fat deposition in salmonids. Moreover, major differences in the metabolism of EPA, DHA and OA at different stages during differentiation of adipocytes occur. Most of the EPA and DHA were oxidized in preadipocytes, while they were mainly stored in TAGs in mature adipocytes in contrast to OA which was primarily stored in TAGs at all stages of differentiation. (c) 2008 Elsevier B.V. All rights reserved.

• Schiøtz, Berit Lyng; Jørgensen, Sven Martin; Rexroad, C; Gjøen, Tor & Krasnov, Aleksei (2008). Transcriptomic analysis of responses to infectious salmon anemia virus infection in macrophage-like cells. Virus Research. ISSN 0168-1702. 136, s. 65–74. doi: 10.1016/j.virusres.2008.04.019. Fulltekst i vitenarkiv
• Trattner, Sofia; Kamal-Eldin, A; Brannas, E; Moazzami, A; Zlabek, V & Larsson, P [Vis alle 9 forfattere av denne artikkelen] (2008). Sesamin Supplementation Increases White Muscle Docosahexaenoic Acid (DHA) Levels in Rainbow Trout (Oncorhynchus mykiss) Fed High Alpha-Linolenic Acid (ALA) Containing Vegetable Oil: Metabolic Actions. Lipids. ISSN 0024-4201. 43(11), s. 989–997. doi: 10.1007/s11745-008-3228-8. Fulltekst i vitenarkiv
• Trattner, Sofia; Ruyter, Bente; Østbye, Tone-Kari K.; Gjøen, Tor; Zlabek, V & Kamal-Eldin, A [Vis alle 7 forfattere av denne artikkelen] (2008). Sesamin Increases Alpha-Linolenic Acid Conversion to Docosahexaenoic Acid in Atlantic Salmon (Salmo salar L.) Hepatocytes: Role of Altered Gene Expression. Lipids. ISSN 0024-4201. 43(11), s. 999–1008. doi: 10.1007/s11745-008-3229-7. Fulltekst i vitenarkiv
• Todorcevic, Marijana; Vegusdal, Anne; Gjøen, Tor; Sundvold, H; Torstensen, BE & Kjær, Marte Avranden [Vis alle 7 forfattere av denne artikkelen] (2008). Changes in fatty acids metabolism during differentiation of Atlantic salmon preadipocytes; Effects of n-3 and n-9 fatty acids. Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids. ISSN 1388-1981. 1781, s. 326–335. doi: 10.1016/j.bbalip.2008.04.014. Fulltekst i vitenarkiv
• Gjøen, Tor; Kleveland, Ellen Johanne; Moya-Falcn, C; Moya-Falcón, Corina; Froystad, MK & Frøystad, Marianne K. [Vis alle 11 forfattere av denne artikkelen] (2007). Effects of dietary thia fatty acids on lipid composition, morphology and macrophage function of Atlantic salmon (Salmo salar L.) kidney. Comparative Biochemistry and Physiology - Part B: Biochemistry & Molecular Biology. ISSN 1096-4959. 148(1), s. 103–111. doi: 10.1016/j.cbpb.2007.04.021. Fulltekst i vitenarkiv
• Gjøen, Tor; Kleveland, Ellen Johanne; Moya-Falcon, Corina; Frøystad, Marianne K.; Vegusdal, Anne & Hvattum, Erlend [Vis alle 8 forfattere av denne artikkelen] (2007). Effects of dietary thia fatty acids on lipid composition, morphology and macrophage function of Atlantic salmon (Salmo salar L.) kidney. Comparative Biochemistry and Physiology - Part B: Biochemistry & Molecular Biology. ISSN 1096-4959. 148. Fulltekst i vitenarkiv Vis sammendrag

  High lipid levels are being used in modem salmonid diets to promote rapid growth; however there is a limiting supply of the traditional fish oils as the fish farming industry expands. One way to utilize the lipid sources better, could be to find ways to stimulate fatty acid (FA) oxidation so that Atlantic salmon use more energy for muscle growth and less for storage in pet visceral adipose tissue. We have previously shown that dietary inclusion of the thia FA tetradecylthioacetic acid (TTA) promoted hepatic beta-oxidation and reduced total body lipid levels. However, dietary TTA also had some negative effects, leading to accumulation of sulfone and sulfoxide metabolites of TTA in the kidney and increasing mortality rates, particularly at low water temperatures. Therefore we also wish to investigate the effects of TTA on kidney function at high and low temperatures, including some immune system parameters. The production of leukotriene B-4 (LTB4) and prostaglandin E-2 (PGE(2)) immunoreactive material from exogenously added arachidonic acid in isolated head kidney macrophages was affected by both diet and temperature. The phagocytic activity in these cells was reduced by DTA in the 12 degrees C group and there was significantly higher protein degradation in head kidney macrophages at 12 degrees C compared to 5 degrees C in all dietary groups. Interestingly, the incorporation of thia FAs in the kidney was higher at 5 degrees C (0.3% TTA and 0.6% DTA) than at 12 degrees C (0.1% TTA and 0.5% DTA). Additionally, there were lower levels of saturated FAs, while higher levels of polyunsaturated FAs (PUFAs) in the kidney of TTA fed fish at 5 degrees C. We also observed temperature-independent tubular dilatation and a reduction in the density of melanomacrophages of the kidney in salmon fed TTA. Nevertheless, the rnRNA expression of some immune-relevant genes in head kidney tissue was not affected by TTA-inclusion in salmon diets. In conclusion, it is clear that 0.6% TTA-inclusion in the feed leads to changes in the kidney function particularly at low water temperatures. (C) 2007 Elsevier Inc. All rights reserved.

• Jørgensen, Sven Martin; Hetland, DL; Press, C.M.; Grimholt, Unni & Gjøen, Tor (2007). Effect of early infectious salmon anaemia virus (ISAV) infection on expression of MHC pathway genes and type I and II interferon in Atlantic salmon (Salmo salar L.) tissues. Fish and Shellfish Immunology. ISSN 1050-4648. 23(3), s. 576–588. doi: 10.1016/j.fsi.2007.01.005. Fulltekst i vitenarkiv
• Jørgensen, Sven Martin; Grimholt, Unni & Gjøen, Tor (2007). Cloning and expression analysis of an Atlantic salmon (Salmo salar L.) tapasin gene. Developmental and Comparative Immunology. ISSN 0145-305X. 31(7), s. 708–719. doi: 10.1016/j.dci.2006.10.004. Fulltekst i vitenarkiv
• Jørgensen, Sven Martin; Grimholt, Unni & Gjøen, Tor (2007). Cloning and expression analysis of an Atlantic salmon (Salmo salar L.) tapasin gene. Developmental and Comparative Immunology. ISSN 0145-305X. 31(1), s. 708–719. Fulltekst i vitenarkiv
• Jørgensen, Sven Martin; Hetland, Dyveke Lem; Press, Charles McLean; Grimholt, Unni & Gjøen, Tor (2007). Effect of early infectious salmon anemia virus (ISAV) infection on expression of MHC pathway genes and type I and II interferon in Atlantic salmon (Salmo salar L.) tissues. Fish and Shellfish Immunology. ISSN 1050-4648. 23(3), s. 576–588. Fulltekst i vitenarkiv
• Jørgensen, Sven Martin; Grimholt, Unni & Gjøen, Tor (2006). Cloning and expression analysis of an Atlantic salmon (Salmo salar L.) tapasin gene. Developmental and Comparative Immunology. ISSN 0145-305X. 20. Fulltekst i vitenarkiv
• Kleveland, Ellen Johanne; Syvertsen, Berit Lyng; Ruyter, Bente; Vegusdal, Anne; Jørgensen, Sven Martin & Gjøen, Tor (2006). Characterization of scavenger receptor class B, type I in Atlantic salmon (Salmo salar L.). Lipids. ISSN 0024-4201. 41(11), s. 1017–1027.. Fulltekst i vitenarkiv
• Kleveland, Ellen Johanne; Ruyter, B; Vegusdal, Anne; Sundvold, H; Berge, RK & Gjøen, Tor (2006). Effects of 3-thia fatty acids on expression of some lipid related genes in Atlantic salmon (Salmo salar L.). Comparative Biochemistry and Physiology - Part B: Biochemistry & Molecular Biology. ISSN 1096-4959. 145, s. 239–248. Fulltekst i vitenarkiv
• Jørgensen, Sven Martin; Lyng-Syvertsen, Berit; Lukacs, Morten; Grimholt, Unni & Gjøen, Tor (2006). Expression of MHC class I pathway genes in response to infectious salmon anaemia virus in Atlantic salmon (Salmo salar L.) cells. Fish and Shellfish Immunology. ISSN 1050-4648. 21(5), s. 548–560. Fulltekst i vitenarkiv Vis sammendrag

  Infectious salmon anaemia virus (ISAV) is the causative agent of an important viral disease threatening Atlantic salmon aquaculture. Although its structure and pathogenesis is well described little is known about its immunomodulatory effects on the host. Cellular immunity is critical in the host control of virus infections, an event attributable to antigen presentation through the MHC class I pathway, whose genes are transcriptionally activated by interferons (IFN) and other cytokines. In this study we analysed the regulation and kinetics of key genes in the salmon MHC class I pathway in relation to type I IFN during ISAV infection and poly I:C stimulation in the permissive Atlantic salmon kidney cell line (ASK). As measured by quantitative real-time PCR, ISAV induced an mRNA shut-off equivalent to 2.5?5.5-fold reduced levels of housekeeping genes at 7 days post infection. Relative to this shut-off (by normalising to ?-actin) transcription increased to peak levels at 2.8-fold for MHC class I, 10-fold for ?2 microglobulin (?2m), 5.9-fold for the peptide transporter ABCB2, 8.8-fold for the proteasome component PSMB8 and 4.6-fold for the proteasome component PSMB9, presumably by activation of the IFN system as a 26-fold induction was observed for type I IFN-?. Expression of Mx protein was also induced 17-fold at peak level. Similar kinetics and activation levels of these genes were seen in poly I:C stimulated cells. We also isolated the salmon MHC class I UBA*0301 promoter and identified a conserved interferon-stimulated response element (ISRE) and GAAA-elements plus several GAS- and IRF-sites, all supporting IFN-inducible properties. In summary, we demonstrate a concerted induction of the MHC class I pathway and type I IFN by ISAV comparable to levels induced by the synthetic double-stranded RNA (dsRNA) poly I:C. Thus, unlike influenza and several other viruses ISAV does not seem to interfere with MHC and IFN expression

• Jørgensen, Sven Martin; Kleveland, Ellen Johanne; Grimholt, Unni & Gjøen, Tor (2006). Validation of reference genes for real-time polymerase chain reaction studies in Atlantic salmon. Marine Biotechnology. ISSN 1436-2228. 8(4), s. 398–408. Fulltekst i vitenarkiv Vis sammendrag

  Optimization of reference genes for real-time polymerase chain reaction (PCR) studies in fish is strongly needed. We systematically tested beta-actin (ACTB), 18S rRNA (18S), beta(2)-microglobulin (B2M), elongation factor 1-alpha (EF1A), RNA polymerase I and II (RPL1/2), and glycerol 6-phosphate dehydrogenase (G6PDH) for stability in salmon immune relevant tissues and kidney cells (ASK) infected with infectious salmon anemia virus (ISAV), plus in tissues from fish fed thia fatty acids. Transcription of all genes was unchanged in infected and thia fatty acid-treated tissues versus normal tissues. Between tissues, 18S and EF1A were most stable, RPL1 and RPL2 were intermediate, and G6PDH and ACTB and B2M were the least stable. However, only 18S had constant expression in infected cells; the rest significantly down-regulated. Implications of this finding were demonstrated when normalizing major histocompatibility complex (MHC) class I expression in ASK. Software predictions supported a proper normalization is obtained combining 18S, EF1A, and RPL1 in vivo, but for in vitro viral infection assays we recommend using 18S.

• Jørgensen, Sven Martin; Kleveland, Ellen Johanne; Grimholt, U & Gjøen, Tor (2006). Validation of reference genes for real-time polymerase chain reaction studies in Atlantic salmon. Marine Biotechnology. ISSN 1436-2228. 8, s. 398–408. Fulltekst i vitenarkiv
• Jørgensen, Sven Martin; Syvertsen, Berit Lyng; Lukacs, Morten; Grimholt, Unni & Gjøen, Tor (2006). Expression of MHC class I pathway genes in response to infectious salmon anaemia virus in Atlantic salmon (Salmo salar L.) cells. Fish and Shellfish Immunology. ISSN 1050-4648. 21(5), s. 548–60. Fulltekst i vitenarkiv
• Malerød, Lene; Sporstol, Marita; Juvet, Lene Kristine; Mousavi, Darbi Seyed Ali; Gjøen, Tor & Berg, Trond [Vis alle 8 forfattere av denne artikkelen] (2005). Bile acids reduce SR-BI expression in hepatocytes by a pathway involving FXR/RXR, SHP, and LRH-1. Biochemical and Biophysical Research Communications - BBRC. ISSN 0006-291X. 336(4), s. 1096–1105. Fulltekst i vitenarkiv
• Vegusdal, Anne; Gjøen, Tor; Berge, Rolf Kristian; Thomassen, Magny Skinlo & Ruyter, Bente (2005). Effect of 18 : 1n-9, 20 : 5n-3, and 22 : 6n-3 on lipid accumulation and secretion by Atlantic salmon hepatocytes. Lipids. ISSN 0024-4201. 40(5), s. 477–486. doi: 10.1007/s11745-005-1407-z. Fulltekst i vitenarkiv Vis sammendrag

  We have studied the effects of dietary FA on the accumulation and secretion of [3H]glycerolipids by salmon hepatocytes in culture. Atlantic salmon were fed diets supplemented with either 100% soybean oil (SO) or 100% fish oil (FO), and grew from an initial weight of 113±5 g to a final weight of 338 ±19 g. Hepatocytes were isolated from both dietary groups and incubated with [3H]glycerol in an FA-free medium; a medium supplemented with 0.75 mM of one of three FA—18∶1n−9, 20∶5n−3, or 22∶6n−3—or a medium supplemented with 0.75 mM of the sulfur-substituted FA analog tetradecylthioacetic acid (TTA), which cannot undergo β-oxidation. Incubations were allowed to proceed for 1,2,6, or 24 h. The rate of the secretion of radioactive glycerolipids with no FA added was 36% lower from hepatocytes isolated from fish fed the FO diet than it was from hepatocytes isolated from fish fed the SO diet. Hepatocytes incubated with 18∶1n−9 secreted more [3H]TAG than when incubated with no FA, whereas hepatocytes incubated with 20∶5n−3 or TTA secreted less labeled TAG than when incubated with no FA. This observation was independent of the feeding group. Hepatocytes incubated with 22∶6n−3 secreted the highest amounts of total [3H]glycerolipids compared with the other treatments, owing to increased secretion of phospholipids and mono- and diacylglycerols (MDG). In contrast, the same amounts of [3H]TAG were secreted from these cells as from cells incubated in an FA-free medium. The lipid-lowering effect of FO is thus independent of 22∶6n−3, showing that 20∶5n−3 is the FA that is responsible for the lipid-lowering effect. The ratio of TAG to MDG in lipids secreted from hepatocytes to which 20∶5n−3 or TTA had been added was lower than that in lipids secreted from hepatocytes incubated with 18∶1n−9 or 22∶6n−3, suggesting that the last step in TAG synthesis was inhibited. Morphometric measurements revealed that hepatocytes incubated with 20∶5n−3 accumulated significantly more cellular lipid than cells treated with 18∶1n−9, 22∶6n−3, TTA, or no treatment. The area occupied by mitochondria was also greater in these cells. The present study shows that dietary FO reduces TAG secretion from salmon hepatocytes and that 20∶5n−3 mediates this effect.

• Vegusdal, Anne; Østbye, Tone-Kari K; Tran, TN; Gjøen, Tor & Ruyter, B (2004). Beta-oxidation, esterification, and secretion of radiolabeled fatty acids in cultivated Atlantic salmon skeletal muscle cells. Lipids. ISSN 0024-4201. 39(7), s. 649–658. Fulltekst i vitenarkiv
• Gjøen, Tor; Obach, A.; Røsjø, Camilla; Grisdale-Helland, Barbara; Rosenlund, G. & Hvattum, E. [Vis alle 7 forfattere av denne artikkelen] (2004). Effect of dietary lipids on macrophage function, stress susceptibility and disease esistance in Atlantic salmon (Salmo salar). Fish Physiology & Biochemistry. ISSN 0920-1742. 30, s. 149–161. doi: 10.1007/s10695-005-4318-7. Fulltekst i vitenarkiv Vis sammendrag

  As the supply of marine fish oil is becoming a limiting factor in the production of Atlantic salmon ( Salmo salar), new diets and alternative sources of energy are being tested. Plant oils are natural potential candidates to replace fish oil, but the different levels of essential polyunsaturated fatty acids may influence the health and growth of salmon. In this study, we have investigated the resistance to transport stress and bacterial infection, phagocytic activity in head kidney macrophages and eicosanoid metabolism in salmon fed three different diets. In high-energy fishmeal based diets, 50% and 100% of the supplementary fish oil (FO) was replaced with soybean oil ( SO). The three dietary groups were fed for 950 day-degrees at 5 degrees C ( 27 weeks) and 12 degrees C ( 11 weeks) before challenging the fish with Aeromonas salmonicida, analyzing the lipid composition of head kidney and examining macrophage function in vivo and in vitro. Dietary fatty acids affected the lipid composition of the kidney. The level of eicosanoid precursor's 20: 4n-6 and 20: 3n-6 were 3 and 7-fold higher in the 100% SO group compared with the FO group. The total fraction of n-3 lipids in kidney was 19% in the SO group, compared to 16% and 12% in the 50% or 100% SO groups, respectively. However, the production of leucotriene B-4 (LTB) and prostaglandin E-2 (PGE) immunoreactive materiel from exogenously added arachidonic acid in head kidney macrophages was only affected by the composite diet ( increased) at 5 degrees C. In addition, the phagocytic activity of kidney macrophages in vivo and in vitro was not affected by diet. No effect of diet was observed on transport stress or susceptibility to a bacterial infection with Aeromonas salmonicida. Atlantic salmon therefore seems to tolerate a diet solely based on soybean oil as lipid source, without any detrimental effects on growth, health and immune functions.

• Vegusdal, Anne; Ostbye, TK; Tran, Thien Ngoc; Gjøen, Tor & Ruyter, Bente (2004). Beta-oxidation, esterification, and secretion of radiolabeled fatty acids in cultivated Atlantic salmon skeletal muscle cells. Lipids. ISSN 0024-4201. 39(7), s. 649–658. Fulltekst i vitenarkiv
• Vegusdal, Anne; Sundvold, Hilde; Gjøen, Tor & Ruyter, Bente (2003). An in vitro method for studying the proliferation and differentiation of Atlantic salmon preadipocytes. Lipids. ISSN 0024-4201. 38(3), s. 289–296. doi: 10.1007/s11745-003-1063-3. Fulltekst i vitenarkiv Vis sammendrag

  The aim of the present study was to develop a cell culture system for studying the proliferation and differentiation of preadipocytes isolated from Atlantic salmon adipose tissue. The expression of proliferating cell nuclear antigen (PCNA) was used as a marker for cell proliferation. The cells started to proliferate within 48 h after seeding and continued to proliferate throughout the culture period of 2 wk. Undifferentiated preadipocytes showed a fibroblast-like morphology with a homogeneous cytoplasm devoid of lipid droplets. At confluence, an exogenous lipid mixture was added to the cell cultures. The preadipocytes became larger and rounder during the subsequent days, and the cytoplasm gradually filled with lipid-rich droplets. These droplets were revealed by oil red O staining. Immunocytochemical staining showed that differentiated adipocytes expressed detectable levels of the three regulatory proteins associated with adipocyte differentiation: peroxisome proliferator-activated receptor gamma (PPARgamma), CCAAT/enhancer binding protein a (C/EBPalpha), and leptin. The cells also showed activity of glycerol-3-phosphate dehydrogenase (GPDH) (EC 1.1.1.8), a biochemical marker of adipocyte differentiation. The morphological and biochemical data presented here show that fish preadipocytes have properties that are similar to those of preadipocytes in mammals. We conclude therefore that salmon adipose tissue contains a sizable population of preadipocytes. Exogenous lipids promote the activation of adipose-related genes and induce the differentiation of fish preadipocytes in vitro.

• Malerød, Lene; Sporstøl, Marita; Juvet, Lene Kristine; Mousavi, Seyed Ali; Gjøen, Tor & Berg, Trond (2003). Hepatic scavenger receptor class B type I, is stimulated by peroxisome proliferator-activated receptor gamma and hepatocyte nuclear factor 4-alpha. Biochemical and Biophysical Research Communications - BBRC. ISSN 0006-291X. 305, s. 557–565. Fulltekst i vitenarkiv
• Malerød, Lene; Sporstol, Marita; Juvet, Lene K.; Mousavi, Seyed Ali; Gjøen, Tor & Berg, Trond (2003). Hepatic scavenger receptor class B, type I is stimulated by peroxisome proliferator-activated receptor gamma and hepatocyte nuclear factor 4alpha. Biochemical and Biophysical Research Communications - BBRC. ISSN 0006-291X. 305(3), s. 557–565. Fulltekst i vitenarkiv
• Kristiansen, Marianne; Frøystad, Marianne Kristin; Rishovd, Anne-Lise & Gjøen, Tor (2002). Characterization of the receptor-destroying enzyme activity from infectious salmon anemia virus (ISAV). Journal of General Virology. ISSN 0022-1317. 83(11), s. 2693–2697. Fulltekst i vitenarkiv Vis sammendrag

  Infectious salmon anaemia virus (ISAV) infects cells via the endocytic pathway and, like many other enveloped viruses, ISAV contains a receptor-destroying enzyme. We have analysed this acetylesterase activity with respect to substrate specificity, enzyme kinetics, inhibitors, temperature and pH stability. The ISAV acetylesterase was inhibited by di-isopropyl fluorophosphate (DFP) in a dose-dependent fashion but not by other known hydrolase inhibitors, suggesting that a serine residue is part of the active site. The pH optimum of the enzyme was in the range 7.5-8.0 and the enzymatic activity was lessened at temperatures above 40 degrees C. The effect of DFP on agglutination/elution of erythrocytes by ISAV demonstrated that the acetylesterase activity is the bona fide receptor-destroying enzyme. A haemadsorption assay was used to analyse whether the esterase was active on the surface of infected cells or not.

• Malerød, Lene; Juvet, Lene Kristine; Gjøen, Tor & Berg, Trond (2002). The expression of scavenger receptor class B, type I (SR-BI) and caveolin-1 in parenchymal and nonparenchymal liver cells. Cell and Tissue Research. ISSN 0302-766X. 307, s. 173–180. Fulltekst i vitenarkiv
• Frøystad, Marianne Kristin; Volden, Vivi; Berg, Trond & Gjøen, Tor (2002). Metabolism of oxidized and chemically modified low density lipoproteins in rainbow trout - clearance via scavenger receptors. Developmental and Comparative Immunology. ISSN 0145-305X. 26, s. 723–733. Fulltekst i vitenarkiv
• Kjeken, Rune; Mousavi, Seyed Ali; Brech, Andreas; Gjøen, Tor & Berg, Trond (2001). Fluid phase endocytosis of 125I-iodixanol in rat liver parenchymal, endothelial and Kupffer cells. Cell and Tissue Research. ISSN 0302-766X. 304, s. 221–230. Fulltekst i vitenarkiv
• Eliassen, Trygve Meum; Frøystad, Marianne Kristin; Dannevig, Birgit Helene; Jankowska, Monika; Brech, A & Falk, Knut [Vis alle 7 forfattere av denne artikkelen] (2000). Initial events in infectious salmon anaemia virus infection: evidence for the requirement of a low-pH step. Journal of Virology. ISSN 0022-538X. 74, s. 218–227. Fulltekst i vitenarkiv
• Hvattum, Erlend; Røsjø, Camilla; Gjøen, Tor; Rosenlund, Grethe & Ruyter, Bente (2000). Effect of soybean oil and fish oil on individual molecular species of Atlantic salmon head kidney phospholipids determined by normal-phase liquid chromatography coupled to negative ion electrospray tandem mass spectrometry. Journal of chromatography. B. ISSN 1570-0232. 748(1), s. 137–149. doi: 10.1016/S0378-4347(00)00359-5. Fulltekst i vitenarkiv Vis sammendrag

  The effect of soybean oil (SO) and fish oil (FO) on the relative molecular species distribution of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI) and phosphatidylserine (PS) in Atlantic salmon head kidney was studied using normal-phase liquid chromatography coupled with negative ion electrospray tandem mass spectrometry. The conformation of identity of the phospholipid species was based on retention time, the mass of the [M-H](-) ([M-15](-) for PC) molecular ions and the carboxylate anion fragments in the product ion spectrum. The intensity ratio of sn-1/sn-2 fragment ions increased with increasing number of double bonds in the sn-2 acyl chain but was not affected by increasing number of double bonds in the sn-1 acyl chain of the species examined. The relative distribution of the molecular species was determined by multiple reaction monitoring of the carboxylate anion fragment from the sn-1 position. A total of 68 different phospholipid species were determined in the head kidney and the largest amount was found in PE (22 species). Depending on the diet, the main species identified in the different phospholipid classes were; PC 16:0/18:1, PE 16:0/22:6, PI 18:0/20:4 and PS 16:0/22:6. The SO diet significantly increased the 18:2, 20:3 and most 20:4 containing species and significantly reduced the 14:0 and most 20:5 and 22:6 fatty acid containing species. The increase of the 20:4 and the decrease of the 20:5 and 22:6 containing species were dependent on the fatty acid combination of the species (C) 2000 Elsevier Science B.V. All rights reserved.

• Hvattum, Erling; Røsjø, Camilla; Gjøen, Tor; Rosenlund, Grete & Ruyter, Bente (2000). Study of the effect of dietary soybean oil on individual molecular species of Atlantic salmon head kidney phospholipids using normal phase liquid chromatography coupled to negative ion electrospray tandem mass spectroscopy. Journal of Chromatography A. ISSN 0021-9673. 748(B), s. 137–149. Fulltekst i vitenarkiv

Se alle arbeider i NVA

• Rimstad, Espen; Brinchmann, Jan Engelsen; Frostegård, Åsa; Sipinen, Ville Erling; Tønnessen, Ragnhild & Blix, Hege Salvesen [Vis alle 9 forfattere av denne artikkelen] (2025). Environmental risk assessment of the genetically modified vaccine Recombitek®C4. VKM Bulletin. VKM Bulletin(VKM Bulletin 2025: 02), s. 1–22. Fulltekst i vitenarkiv Vis sammendrag

  Det er ikke høyere miljørisiko ved bruk av den genmodifiserte vaksinen Recombitek®C4 enn ved bruk av tilsvarende godkjente vaksiner. Det er hovedbudskapet i en risikovurdering VKM har gjort for Miljødirektoratet. Bakgrunn Miljødirektoratet har mottatt en søknad etter genteknologiloven om bruk av vaksinen Recombitek®C4 i det nasjonale avlsprogrammet for fjellrev (Vulpes lagopus). Fjellreven er klassifisert som en sterkt truet art i Norge. Avlsprogrammet er etablert som del av bevaringsarbeidet og driftes av Norsk institutt for naturforskning (NINA). Ved avlsstasjonen i Oppdal har fire revevalper dødd av smittsom leverbetennelse (hepatitis contagiosa canis (HCC)), og man ønsker å bruke denne vaksinen for å hindre ytterligere smitte. Det finnes godkjente alternative vaksiner til Recombitek®C4, men disse ønsker man ikke å bruke fordi vaksinene inneholder et svekket (for hund), men levende valpesykevirus (CDV), som kan føre til sykdom hos fjellrev. Recombitek®C4 er pr i dag ikke godkjent i Norge eller i EU, men er blitt regelmessig brukt til vaksinasjon av hunder i over 20 år, blant annet i USA og Canada. Miljødirektoratet har bedt VKM utføre en miljørisikovurdering av vaksinen Recombitek®C4 i henhold til genteknologiloven VKMs vurdering Vaksinen Recombitek®C4 inneholder en kanarikoppevirusvektor kalt ALVAC. ALVAC er basert på Kanarikoppeviruset (CNPV), som først og fremst forårsaker sykdom hos spurvefugler, som kanarifugl. Forløpet kjennetegnes ved sykdom i hud og difteriliknende symptomer, med mulig høy dødelighet. ALVAC er en genetisk konstruert, svekket variant av CNPV, designet for bruk i vaksiner. Hverken vektoren eller viruset kan produsere eller spre nye virus mellom pattedyr. Dermed vil den mest sannsynlige veien til miljøet være via overføring til ville fugler. Avlsstasjonen i Oppdal rapporterer om en viss interaksjon mellom fjellrev og fugler, som ørn, ravn og kråke, bl.a. rundt fôrplasseringer. For å minimere mulig kontakt mellom rev og fugl, bruker man fôringsbokser og spesielle «ørnestrukturer» i innhegningene. Dersom ørn eller andre fugler likevel skulle komme i kontakt med ALVAC i perioden revene vaksineres, anses faren for smitte, sykdom og spredning blant fugler som svært usannsynlig. Flere vaksiner som inneholder ALVAC er godkjente til bruk på dyr i Norge, for eksempel i vaksiner til katt og hest. VKM konkluderer at bruk av Recombitek®C4 i det nasjonale avlsprogrammet for den rødlistede arten fjellrev ikke utgjør en økt miljørisiko sammenlignet med tilsvarende vaksiner med ALVAC-vektoren allerede i bruk for andre dyrearter i Norge. Risikovurderingen er godkjent av VKMs faggruppe for genmodifiserte organismer - legemidler.

• Nyfløt, Hilda; Spurkland, Anne & Gjøen, Tor (2022). Smittsomt marburgvirus tar livet av to personer i Ghana. [Internet]. NRK.no. Fulltekst i vitenarkiv
• Griffiths, Gareth Wyn; Müller, Ference; Ledin, Johan; Patton, E. Elizabeth; Gjøen, Tor & Lobert, Viola [Vis alle 12 forfattere av denne artikkelen] (2016). Fish from Head to Tail: The 9th European Zebrafish Meeting in Oslo. Zebrafish. ISSN 1545-8547. 13(2), s. 132–137. doi: 10.1089/zeb.2015.1212. Fulltekst i vitenarkiv
• Arnemo, Marianne; Kavaliauskis, Arturas; Bou, Marta; Berge, Gerd Marit; Ruyter, Bente & Gjøen, Tor (2014). Effect of dietary omega-3 fatty acids on viral infection and toll-like receptor activation in macrophages from Atlantic salmon. Fulltekst i vitenarkiv
• Bou, Marta; Berge, Gerd Marit; Leeuwis, Robin; Østbye, Tone-Kari K; Sigholt, Trygve & Hatlen, Bjarne [Vis alle 10 forfattere av denne artikkelen] (2014). Minimum requirements of essential omega-3 fatty acids in Atlantic salmon in sea water. Fulltekst i vitenarkiv
• Ruyter, Bente; Bou, Marta; Østbye, Tone-Kari K; Leewis, Robin; Sigholt, Trygve & Hatlen, Bjarne [Vis alle 9 forfattere av denne artikkelen] (2014). Minimumsbehov for essensielle omega-3 fettsyrer i Atlantisk laks. Fulltekst i vitenarkiv
• Arnemo, Marianne; Kavaliauskis, Arturas & Gjøen, Tor (2013). Identification of fish Toll-like receptor ligands with a NF-kB luciferase reporter system. Fish and Shellfish Immunology. ISSN 1050-4648. 34(6), s. 1694–1695. Fulltekst i vitenarkiv
• Yazdani, Mazyar; Paulsen, Ragnhild Elisabeth; Gjøen, Tor & Hylland, Ketil (2013). Reactive oxygen species and cytotoxicity in rainbow trout hepatocytes: effects of medium and incubation time. Fulltekst i vitenarkiv
• Arnemo, Marianne; Kavaliausikis, Arturas; Esteba, Amparo; Sonia, Dios; Beatriz, Novoa & Gjøen, Tor (2013). The use of zebrafish as a model system for development of new adjuvant strategies in finfish DNA vaccination against viruses. Journal of Immunology. ISSN 0022-1767. 190. Fulltekst i vitenarkiv
• Kayaliauskis, A.; Arnemo, Marianne & Gjøen, Tor (2013). Development of new nanoparticulate vaccines against fish viruses in aquaculture. Fish and Shellfish Immunology. ISSN 1050-4648. 34(6), s. 1714–1714. Fulltekst i vitenarkiv
• Yazdani, Mazyar; Paulsen, Ragnhild Elisabeth; Gjøen, Tor & Hylland, Ketil (2011). Comparison of three fluorescence probes for ROS detection in primary cultures of rainbow trout hepatocytes. Fulltekst i vitenarkiv
• Aursnes, Ingrid Augusta Stølen; Gjøen, Tor & Rishovd, Anne-Lise (2009). Effect of hyperthermia on plasma lipids and gene expression in Atlantic Cod. (Gadus Morhua I.). Toxicology Letters. ISSN 0378-4274. 189, s. S192–S192. doi: 10.1016/j.toxlet.2009.06.582. Fulltekst i vitenarkiv
• Hetland, Dyveke Lem; Jørgensen, Sven Martin; Grimholt, Unni; Gjøen, Tor & Press, Charles McLean (2007). Expression of major histocompatibility complex (MHC) class I and II in Atlantic salmon (Salmo Salar L.) after infection with infectious salmon anaemia virus (ILAV). Fulltekst i vitenarkiv
• Kleveland, Ellen Johanne; Sundvold, Hilde; Ruyter, Bente & Gjøen, Tor (2005). Effect of dietary lipids on expression of lipoproteins, lipoprotein receptors and PPARs in Atlantic salmon. The FASEB Journal. ISSN 0892-6638. s. 1055–1055. Fulltekst i vitenarkiv
• Kleveland, Ellen Johanne; Sundvold, Hilde; Ruyter, Bente & Gjøen, Tor (2005). Effect of dietary lipids on expression of lipoproteins, lipoprotein receptors and PPARs in Atlantic salmon. The FASEB Journal. ISSN 0892-6638. 19. Fulltekst i vitenarkiv
• Syvertsen, Berit Lyng; Mjaaland, S & Gjøen, Tor (2005). Apoptosis in infectious salmon anemia virus infected cells. The FASEB Journal. ISSN 0892-6638. 19. Fulltekst i vitenarkiv
• Jorgensen, SM; Grimholt, Unni; Skjodt, K; Gjøen, Tor & Rishovd, Anne-Lise (2005). Cellular and tissue responses on Atlantic salmon (Salmo salar L.) MHC class I genes during ISAV infection. The FASEB Journal. ISSN 0892-6638. 19. Fulltekst i vitenarkiv
• Syvertsen, B.L.; Mjaaland, Siri & Gjøen, Tor (2005). Apoptosis in infectious salmon anemia virus infected cells. The FASEB Journal. ISSN 0892-6638. s. 402–402. Fulltekst i vitenarkiv
• Liland, Nina Sylvia; Sissener, Nini; Østbye, Tone-Kari K; Gjøen, Tor; Bou, Marta & Holen, Elisabeth [Vis alle 12 forfattere av denne artikkelen] (2021). Trenger laks fettsyren EPA for optimal immunrespons? Rapport FHF prosjekt EPA-laks. FHF. Fulltekst i vitenarkiv Vis sammendrag

  Innhold av de langkjedede omega-3 fettsyrene i dietter blir ofte oppgitt som sum EPA + DHA, uten å ta spesielt hensyn til ratioen mellom de to fettsyrene. Laksens behov for DHA er velstudert. EPA omgjøres i stor grad til DHA og brukes til energi av cellene i større grad enn DHA. En har derfor lenge tenkt at DHA er mer essensiell enn EPA. Forsøk viser nå indikasjoner på at EPA har en unik og spesiell rolle i immunforsvaret til Atlantisk laks, spesielt når de er utsatt for virusinfeksjon. Dette prosjektet har sett nærmere på rollen til EPA i inflammatoriske prosesser og immunrespons til Atlantisk laks. Hovedvekten av arbeidet har blitt gjort ved hjelp av ulike cellemodeller. I tillegg til å gi kunnskap om EPA, har prosjektet også gitt nyttig kunnskap om hvordan ulike cellemodeller kan bli brukt i studier på interaksjoner mellom fettsyrer og inflammasjon-/immunrespons.

• Ruyter, Bente; Sissener, Nini; Royo, Esmail Lutfi; Hundal, Bjørg Kristine; Berge, Gerd Marit & Glencross, Brett [Vis alle 22 forfattere av denne artikkelen] (2021). Optimalisering av fett og fettsyrer i fôr til atlantisk laks for bedre helse og velferd gjennom ulike livsfaser og utfordrende miljøbetingelser. Nofima. ISSN 9788282966818. Fulltekst i vitenarkiv Vis sammendrag

  Hovedmålet med prosjektet har vært å skaffe til veie ny kunnskap om hvilke nivåer av fett og fettsyrer som kreves for å sikre produksjonen av en robust atlantisk laks i ulike livsfaser og under ulike produksjonsforhold. Resultater fra prosjektet viste at fôring med en planteoljerik diett i ferskvannsfasen bedret tilveksten til laksen, mens økende nivåer av EPA og DHA i fôret bedret tilveksten i sjøvannsfasen. Laks som var tilvent høyt nivå av planteoljer i fôret i ferskvannsfasen med god tilvekst, hadde ingen fordeler etter overføringen til sjøvann sammenlignet med en laks fôret høyere nivåer av marine oljer. Immunresponsen etter vaksinering var lite påvirket av fettsyresammensetningen av dietten til laksen. Behovet for EPA og DHA, basert på vekstrespons under ideelle miljøforhold i tidlig sjøvannsfase, ble definert til 5 % - 7 % av totale fettsyrer i dietten, men i senere faser i merder i sjø under utfordrende miljøforhold kan dataene tyde på økt behov for disse fettsyrene for å opprettholde god helse og muskelkvalitet, da økende nivåer av EPA og DHA i fôret fra 10 g/kg til 35 g/kg (4-10 % av totale fettsyrer) bedret vekst, velferds- og helseindikatorer, muskelkvalitet og mineralstatus til laksen. Økt energinivå (fettnivå) i fôret bedret veksten til laksen i tidlig sjøvannsfase, mens i seinere fase i merder i sjø førte lavere fettnivå (økt proteinnivå) til bedret tilvekst. Økt energiinnhold i dietten økte ytelsen til laksen under hypoksistress, men resulterte i mindre sunt tarmmikrobiom og hjertehelse og lavere mineral og sinknivå i helkropp. Genetisk seleksjon for høy kapasitet til syntese av EPA og DHA førte til redusert fettnivå og økte nivåer av EPA og DHA i lever til laks fôret en diett rik på planteolje (bedret leverhelse). Forhøyet n-6 / n-3 ratio i fôret gav økt leverfett og etter hypoksistress førte økt ratio til redusert kortisolrespons i plasma og økte nivåer av eikosanoidene PGE2 og PGD2 i leveren, men påvirket ikke sykdomsforløpet og uttrykk av gener relatert til immunrespons under AGD gjelleinfeksjon.

• Rimstad, Espen; Basic, Dean; Brun, Edgar; Colquhoun, Duncan John; Olesen, Niels Jørgen & Bøe, Knut Egil [Vis alle 13 forfattere av denne artikkelen] (2019). The risk of transmission of infectious disease through trade of cryopreserved milt. Scientific Opinion of the Panel on Animal Health and Welfare of the Norwegian Scientific Committee for Food Safety. Norwegian Scientific Committee for Food and Environment (VKM). ISSN 9788282593182. Fulltekst i vitenarkiv
• Nielsen, Kaare Magne; Gjøen, Tor; Asare, Nana Yaa Ohene; Lunestad, Bjørn Tore; Ytrehus, Bjørnar & Yazdankhah, Siamak Pour [Vis alle 11 forfattere av denne artikkelen] (2018). Antimicrobial resistance in wildlife potential for dissemination. Opinion of the Panel on Microbial Ecology of the Norwegian Scientific Committee for Food and Environment. Vitenskapskomiteen for mat og miljø. ISSN 9788282593045. Fulltekst i vitenarkiv Vis sammendrag

  <p>Antimicrobial resistance (AMR) is recognised as one of the greatest public health concerns of our time. The development of AMR occurs in nature as a defence by microbes against naturally occurring antimicrobials. However, the selective pressure, generated by the use of antimicrobial agents in human and veterinary medicine, livestock and plant production as well as aquaculture practices, is the major driving force leading to the increased emergence and spread of resistance in bacteria. The sharing of common habitats and water resources could result in transfer of antimicrobial-resistant bacteria (ARB) between wildlife, foodproducing animals and humans. Bacterial populations with various transferable AMR traits are reported in wildlife, and wildlife is thus a well-established source of AMR bacteria entering the food chain both in meat and in foods of plant origin. The relative importance of such reservoirs and transfer routes of AMR in comparison to other sources leading to AMR development in pathogenic bacteria remains unclear.</p> <p>The Norwegian Environment Agency (Miljødirektoratet) asked the Norwegian Scientific Committee for Food and Environment (VKM) for an assessment regarding the role of wildlife in dissemination of AMR. The Norwegian Environment Agency would like VKM to give an opinion on wildlife and AMR:</p> <ul><li>Identification of transferable AMR bacteria in wildlife (terrestrial and aquatic animals).</li> <li>Methods used for sampling and analysis of data in reported studies.</li> <li>AMR in bacteria in wildlife, according to their habitat (close to urban areas, rural areas, marine or freshwater environment or migratory).</li> <li>Possible routes of antimicrobial residues to induce ARB in the environment.</li> <li>Transfer of AMR bacteria between wildlife and other hosts, possible routes of dissemination of ARB to wildlife from domestic animals and vice versa, exchange routes of AMR between human and wildlife.</li></ul> <p>VKM appointed a working group, consisting of one member of the Panel on Microbial Ecology, one member of the Panel on Genetically Modified Organisms, one external member, and VKM staff to prepare a draft Opinion. The Panel on Microbial Ecology has reviewed and revised the draft prepared by the working group and approved the Opinion document. In this opinion, we summarise the majority of research conducted on AMR in wildlife, identify knowledge gaps and areas of uncertainty, and explore the interfaces between wildlife, domestic animals, and humans in the context of resistance emergence, persistence, and transmission.</p>

• Okoli, Arinze Stanley; Asare, Nana Yaa Ohene; Gjøen, Tor; Klein, Jörn & Ytrehus, Bjørnar (2016). Knowledge base for the assessment of environmental risks by the use of genetically modified virus-vectored vaccines for domesticated animals. The Norwegian Scientific Committee for Food Safety. ISSN 9788282592390. Fulltekst i vitenarkiv
• Källqvist, Torsten; Dirven, Hubert; Gjøen, Tor; Tronsmo, Arne; Yazdankhah, Siamak Pour & Rivedal, Edgar [Vis alle 13 forfattere av denne artikkelen] (2016). Risk assessment of the biological plant protection product Turex 50 WG, with the organism Bacillus thuringiensis ssp. aizawai CG-91. Opinion of the Panel on Plant Protection Products of the Norwegian Scientific Committee for Food Safety. Nofima. ISSN 9788282592109. Fulltekst i vitenarkiv Vis sammendrag

  Bacillus thuringiensis are anaerobic, gram-positive bacteria that produce parasporal crystalline protein inclusions, δ-endotoxin, which are toxic to certain invertebrates, especially larvae belonging to the insect orders Coleoptera, Diptera and Lepidoptera. Different strains of Bacillus thuringiensis have therefore a long standing history as plant protective insecticides in many countries, but have not been approved for use in Norway. The Norwegian Scientific Committee for Food Safety (Vitenskapskomiteen for mattrygghet, VKM) has been asked by The Norwegian Agency for Food safety to assess the health and environment related aspects related to the use of the plant protection product Turex 50 WG, containing the active ingredient Bacillus thuringiensis ssp. aizawai CG-91.

• Källqvist, Torsten; Dirven, Hubert; Gjøen, Tor; Tronsmo, Arne; Yazdankhah, Siamak Pour & Rivedal, Edgar [Vis alle 13 forfattere av denne artikkelen] (2016). Risk assessment of the biological plant protection product Serenade ASO, with the organism Bacillus subtilis QST 713. Opinion of the Panel on Plant Protection Products of the Norwegian Scientific Committee for Food Safety. Nofima. ISSN 9788282592116. Fulltekst i vitenarkiv Vis sammendrag

  Bacillus subtilis are gram-positive bacteria that occur globally in soil, water, air, and decomposing plant material. The Bacillus bacteria are responsive to genetic alterations, and a large number of bacteria strains are part of the Bacillus genus. Some of the Bacillus bacteria strains have acquired genes for pathogenic toxins, but available techniques exist to identify and discriminate between the different strains. Bacillus subtilis has been used for industrial enzyme and food production, and even as a probiotic to treat gastro intestinal tract symptoms and disorders, including diarrhoea in infants and young children. Bacillus subtilis has been shown to act fungistatic and fungitoxic following contact with fungal pathogens at leaf or root surfaces, and may therefore be used as a biological fungicide in different crops. The Norwegian Scientific Committee for Food Safety (Vitenskapskomiteen for mattrygghet, VKM) has been asked by The Norwegian Agency for Food safety to assess the health and environment related aspects related to the use of the plant protection product Serenade ASO, containing the active ingredient Bacillus subtilis QST 713. VKM has considered the data presented for the Bacillus subtilus strain QST713, and shares the opinion of EFSA, and also US Environmental Protection Agency, in that Bacillus subtilis “is considered a benign organism as it does not possess traits that cause disease. It is not considered pathogenic or toxigenic to humans, animals, or plants.” Bacillus subtilis is ubiquitously present in water, air and soil, also in Norway, and subject to competition by other indigenous microorganisms. Thus, the number of introduced Bacillus subtilis will rapidly decline and reach a natural equilibrium in nature. Bacillus subtilis show low or acceptable toxicity in terrestrial and aquatic non-target organisms. Effects on nontarget micro-organisms cannot be excluded, but are not expected to adversely affect natural microbial communities. The possible risk related to Bacillus subtilis is linked to the possibility of miss-identifying a toxic Bacillus strain such as Bacillus anthracis or Bacillus cereus for Bacillus subtilis. Thus, VKM emphasizes the importance of product control, to ensure and document the identity, purity and relevant contents and property of each product batch prior to marketing and use. Bacillus subtilis is not known to produce toxins, but produce proteolytic enzymes considered to be responsible for effects observed in inhalation experiments. Thus, proper preventive equipment should be used.

• Skaar, Ida; Asare, Nana Yaa Ohene; Klein, Joern; Okoli, Arinze Stanley; Ruus, Anders & Gjøen, Tor [Vis alle 10 forfattere av denne artikkelen] (2016). Health and environmental risk evaluation of microorganisms used in bioremediation. Scientific Opinion of the Panel on Microbial Ecology of the Norwegian Scientific Committee for Food Safety. Nofima. ISSN 9788282592321. Fulltekst i vitenarkiv Vis sammendrag

  In 2015, The Norwegian Environment Agency requested the Norwegian Scientific Committee for Food Safety (VKM) to collate an overview of bioremediation of polluted ground based on bioaugmentation described in literature for the degradation of various types of pollutants, (including hydrocarbons, heavy metals, chlorinated compounds, explosives etc.).The assessment of genetically modified microorganisms (GMO), phytoremediation, bioremediation based on natural attenuation, bio-stimulation or biodegradation, including composting, are not included in this report.

• Okoli, Arinze Stanley; Asare, Nana Yaa Ohene; Gjøen, Tor; Klein, Joern; Ytrehus, Bjørnar & Godfroid, Jacques [Vis alle 9 forfattere av denne artikkelen] (2016). Knowledge base for the assessment of environmental risks by the use of genetically modified virus-vectored vaccines for domesticated animals. Scientific Opinion of the Panel on Microbial Ecology of the Norwegian Scientific Committee for Food Safety. Nofima. ISSN 9788282592390. Fulltekst i vitenarkiv Vis sammendrag

  The Norwegian Scientific Committee for Food Safety (VKM) was requested by the Norwegian Environment Agency in November 2015 to develop a knowledge base for assessment of the environmental risks related to the use of genetically modified (GM) virus vaccine vectors for vaccination of domesticated animals. The Agency requested that the task be conducted in the form of a desk study with the following mandate: (1) to provide a short description of GM virus vectors in use in veterinary vaccines; (2) summarize available information relevant to environmental risk assessment (ERA) of GM veterinary virus vaccines; and (3) identify environmental risk factors and knowledge gaps of relevance to ERA of GM virus vaccines within the Norwegian context. This report provides background for future environmental risk assessment of veterinary medicinal products containing or consisting of GMO for use in Norway.<p> <p>VKM has appointed a working group consisting of members of the Panel on Microbial Ecology and the VKM secretariat to answer the request. The VKM Panel has reviewed and revised the draft prepared by the working group and finally approved the opinion.<p> <p>This Report contains the findings of a desk study of current virus vectors used in GM virus vectored vaccines of domesticated livestock. A survey of the published literature for current knowledge in the area was undertaken with the aim of providing information relevant to the ERA of veterinary GM virus vectors (GM-VV). In identifying potential risk factors associated with vaccination of domesticated animals using GM-VV, focus was on the Norwegian environment, but relevant parallels were drawn from other European countries.<p>

• Skaar, Ida; Asare, Nana Yaa Ohene; Godfroid, Jacques; Jelmert, Anders; Ytrehus, Bjørnar & Gjøen, Tor [Vis alle 9 forfattere av denne artikkelen] (2016). Health and environmental risk assessment of microbial cleaning products. Scientific Opinion of the Panel on Microbial Ecology of the Norwegian Scientific Committee for Food Safety. Nofima. ISSN 9788282592314. Fulltekst i vitenarkiv Vis sammendrag

  In 2015, The Norwegian Environment Agency requested the Norwegian Scientific Committee for Food Safety (VKM) to provide a scientific assessment of the information requirements laid down in the declaration form for the Regulation on microbial products and its guidelines, if these are sufficient to conduct a health and environmental risk assessment of the use of microbial cleaning products in Norway. VKM appointed a working group consisting of members of the Panel on Microbial Ecology. The Panel on Microbial Ecology has reviewed and revised the draft prepared by the working group, and the assessment has been adopted.

• Tronsmo, Arne; Gjøen, Tor; Sørum, Henning; Godfroid, Jacques; Yazdankhah, Siamak Pour & Jelmert, Anders [Vis alle 10 forfattere av denne artikkelen] (2016). Antimicrobial resistance due to the use of biocides and heavy metals: a literature review. Opinion of the Panel Panel on Microbial Ecology of the Norwegian Scientific Committee for Food Safety. Vitenskapskomiteen for mat og miljø. ISSN 9788282592536. Fulltekst i vitenarkiv

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