Blar i Bergen Open Research Archive på forfatter "Hordvik, Ivar"
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Analysis of immunoglobulin and T cell receptor gene expression in ballan wrasse (Labrus bergylta) revealed an extraordinarily high IgM expression in the gut
Bilal, Sumaira; Lie, Kai Kristoffer; Dalum, Alf Seljenes; Karlsen, Odd Andre; Hordvik, Ivar (Peer reviewed; Journal article, 2019)The serum IgM concentration of ballan wrasse is relatively high, estimated to approximately 13 mg/ml in adult wild fish of 800 g. The present study revealed an unusual high abundance of IgM mRNA in the gut of ballan wrasse. ... -
The Distribution of IgT mRNA+ Cells in the Gut of the Atlantic Salmon (Salmo salar L.)
Castro, Pedro Luis; Barac, Fran; Hansen, Tom Johnny; Fjelldal, Per Gunnar; Hordvik, Ivar; Bjørgen, Håvard; Koppang, Erling Olaf (Journal article; Peer reviewed, 2023)The newly discovered IgT+ B cell is thought to play a dominant role in mucosal immunity, but limited studies have examined its distribution in fish species, hindering our understanding of its function. This study investigated ... -
Ectopic epithelial cell clusters in salmonid intestine are associated with inflammation
Bjørgen, Håvard; Koppang, Erling Olaf; Gunnes, Gjermund; Hordvik, Ivar; Moldal, Torfinn; Kaldhusdal, Magne; Dale, Ole Bendik (Peer reviewed; Journal article, 2018-06-11)An epizootic incidence of intestinal adenocarcinomas was reported in brood fish of Atlantic salmon (Salmo salar L.) in 2009. The condition was associated with a specific diet inducing enteritis and morphological changes. ... -
Evaluation of potential reference genes in real-time RT-PCR studies of Atlantic salmon
Olsvik, Pål A.; Lie, Kai Kristoffer; Olderbakk Jordal, Anne-Lise; Nilsen, Tom Ole; Hordvik, Ivar (Peer reviewed; Journal article, 2005)Background: Salmonid fishes are among the most widely studied model fish species but reports on systematic evaluation of reference genes in qRT-PCR studies is lacking. Results: The stability of six potential reference genes ... -
Gene expression analyses of immune responses in Atlantic salmon during early stages of infection by salmon louse (Lepeophtheirus salmonis) revealed bi-phasic responses coinciding with the copepod-chalimus transition
Tadiso, Tariku Markos; Krasnov, Aleksei; Skugor, Stanko; Afanasyev, Sergey; Hordvik, Ivar; Nilsen, Frank (Peer reviewed; Journal article, 2011-03-07)The salmon louse (Lepeophtheirus salmonis Krøyer), an ectoparasitic copepod with a complex life cycle causes significant losses in salmon aquaculture. Pesticide treatments against the parasite raise environmental concerns ... -
Immunoglobulin Isotypes in Atlantic Salmon, Salmo Salar
Hordvik, Ivar (Peer reviewed; Journal article, 2015-02)There are three major immunoglobulin (Ig) isotypes in salmonid fish: IgM, IgD and IgT, defined by the heavy chains , and , respectively. As a result of whole genome duplication in the ancestor of the salmonid fish family, ... -
Intramuscular vaccination of Atlantic lumpfish (Cyclopterus lumpus L.) induces inflammatory reactions and local immunoglobulin M production at the vaccine administration site
Erkinharju, Toni; Strandskog, Guro; Vågnes, Øyvind; Hordvik, Ivar; Dalmo, Roy Ambli; Seternes, Tore (Peer reviewed; Journal article, 2019)Atlantic lumpfish were vaccinated by intramuscular (im) or intraperitoneal (ip) injection with a multivalent oil‐based vaccine, while control fish were injected with phosphate‐buffered saline. Four lumpfish per group were ... -
The ontogeny of lymphoid organs and IgM+ B-cells in ballan wrasse (Labrus bergylta) reveals a potential site for extrarenal B-cell lymphopoiesis: The pancreas
Etayo, Angela; Bjørgen, Håvard; Koppang, Erling Olaf; Lie, Kai Kristoffer; Bjelland, Reidun Marie; Hordvik, Ivar; Øvergård, Aina-Cathrine; Sæle, Øystein (Journal article; Peer reviewed, 2024)Vaccination of farmed fish is the most effective prophylactic measure against contagious diseases but requires specific knowledge on when the adaptive immune system is fully developed. The present work describes kidney and ... -
Organisation of the Atlantic salmon (Salmo salar) thymus and its content of Ig-expressing cells
Bjørgen, Håvard; Barac, Fran; Fjelldal, Per Gunnar; Hansen, Tom Johnny; Hordvik, Ivar; Koppang, Erling Olaf (Journal article; Peer reviewed, 2024)The thymus of fishes is located as a dual organ in a rostrodorsal projection within the gill chamber and is covered by the operculum. The histological organization of the teleost fish thymus displays considerable diversity, ... -
T cell receptor alpha chain genes in the teleost Ballan wrasse (Labrus bergylta) are subjected to somatic hypermutation
Bilal, Sumaira; Lie, Kai Kristoffer; Sæle, Øystein; Hordvik, Ivar (Peer reviewed; Journal article, 2018-05-22)Previously, somatic hypermutation (SHM) was considered to be exclusively associated with affinity maturation of antibodies, although it also occurred in T cells under certain conditions. More recently, it has been shown ... -
The teleost polymeric Ig receptor counterpart in ballan wrasse (Labrus bergylta) differs from pIgR in higher vertebrates
Etayo, Angela; Bjørgen, Håvard; Koppang, Erling Olaf; Hordvik, Ivar (Journal article; Peer reviewed, 2022)As mucosal barriers in fish are the main sites where pathogens are encountered, mucosal immunity is crucial to avoid infection in the aquatic environment. In teleost fish, immunoglobulins are present in gut, gill and skin ... -
A teleost structural analogue to the avian bursa of Fabricius
Løken, Oskar Mongstad; Bjørgen, Håvard; Hordvik, Ivar; Koppang, Erling Olaf (Peer reviewed; Journal article, 2019-12-26)The bursa of Fabricius is a primary and secondary lymphoid organ considered exclusively present in birds, and studies of this structure have been vital to our current understanding of the adaptive immune system of vertebrates. ... -
The thymus and T-cell ontogeny in ballan wrasse (Labrus bergylta) is nutritionally modelled
Etayo, Angela; Lie, Kai Kristoffer; Bjelland, Reidun Marie; Hordvik, Ivar; Øvergård, Aina-Cathrine; Sæle, Øystein (Journal article; Peer reviewed, 2023-05-01)Marine fish larvae often experience high mortality unrelated to predation during early life stages, and farmed ballan wrasse (Labrus bergylta) is no exception. Knowing when the adaptive immune system is developed and fully ... -
The zebrafish homeobox gene Hox(zf-114): primary structure, expression pattern and evolutionary aspects
Molven, Anders; Hordvik, Ivar; Njølstad, Pål Rasmus; Gheulue, M. van; Fjose, Anders (Peer reviewed; Journal article, 1992)It is gradually becoming accepted that vertebrate homeobox genes, like their counterparts in Drosophila, are crucial for normal development of the embryo. Most vertebrate homeoboxes reported so far are related to the ...