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At least 19 recordsLinked to original sources
PubMed2007

Neurotrophin and Trk neurotrophin receptors in the inner ear of Salmo salar and Salmo trutta.

Neurotrophins (NTs) and their signal transducing Trk receptors play a critical role in the development and maintenance of specific neuronal populations in the nervous system of higher vertebrates. They are responsible for the innervation of the inner ear cochlear and vestibular sensory epithelia. Neurotrophins and Trks are also present in teleosts but their distribution in the inner ear is unknown. Thus, in the present study, we used Western-blot analysis and immunohistochemistry to investigate the expression and cell localization of both NTs and Trk receptors in the inner ear of alevins of Salmo salar and Salmo trutta. Western-blot analysis revealed the occurrence of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), but not nerve growth factor (NGF), as well as all three Trk receptors, i.e. TrkA, TrkB and TrkC, the estimated molecular weights of which were similar to those expected for mammals. Specific immunoreactivity for neurotrophins was detected mainly in the sensory epithelia. In particular, BDNF immunoreactivity was found in the maculae of the utricle and saccule, whereas NT-3 immunoreactivity was present in the sensory epithelium of the cristae ampullaris. As a rule the sensory epithelia of the inner ear lacked immunoreactivity for Trks, thus excluding possible mechanisms of autocrinia and/or paracrinia. By contrast, overlapping subpopulations of neurons in the statoacoustic ganglion expressed TrkA (about 15%), TrkB (about 65%) and TrkC (about 45%). The present results demonstrate that, as in mammals and birds, the inner ear of teleosts expresses the components of the neurotrophin-Trk system, but their roles remain to be elucidated.

Animals↗
PubMed1996

A NOR-associated repetitive element present in the genome of two Salmo species (Salmo salar and Salmo trutta).

A repetitive element was isolated from the genome of Atlantic salmon. Nucleotide sequence analysis revealed the existence of variant monomers that range in length from approximately 200 to 230 bp. Repeat monomers contain regions of cryptic simplicity, internal repetition, and long direct repeats with deletions and insertions between individual units. The repetitive element was shown to have a tandem unit arrangement and was estimated to occupy between two and three percent of the Atlantic salmon genome. Southern blot analysis revealed the repetitive element to be unique to Atlantic salmon and brown trout species. In situ hybridization analysis showed this element to be localized at the main nucleolar organizer region bearing chromosomes of Atlantic salmon (Salmo salar), AS cell line (derived from S. salar), and brown trout (Salmo trutta).

Animals↗
PubMed1979

Nucleus praeopticus and nucleus lateralis tuberis of Salmo salar and Salmo gairdneri: structure and relationship to the hypophysis.

The nucleus praeopticus (NPO) is located on both sides of the preoptic recess and is composed of a pars parvocellularis and a pars magnocellularis. Only in the rainbow trout does the pars magnocellularis consist of separately located medium-sized cells and very large cells. Cytologically, three cell types can be distinguished: 1) unipolar cells ending in the cerebrospinal fluid (CSF), 2) bipolar cells also ending in the CSF and forming an axon, and 3) multipolar cells which generally do not have a direct connection with the ventricle. Axons originate from the cell bodies forming the paired preopticohypophysial tract that runs along the border of the diencephalon and the optic tract. A considerable number of NPO fibers leading to the hypophysis makes close contact with the cell bodies of the pars lateralis of the nucleus lateralis tuberis, indicating a functional relationship. Most NPO fibers terminate in the caudal part of the neurohypophysis, around blood capillaries and at the basal lamina of the pars intermedia. Far fewer fibers appear to terminate near the boundary of the neurohypophysis and the rostral and proximal pars distalis. The nucleus lateralis tuberis (NLT) is located in the caudal hypothalamus, beginning at the rostral end of the horizontal commissure and extending caudally beyond the hypophysial stalk. It consists of the partes rostralis, medialis, lateralis and ventrolateralis. In both species the p. rostralis contains small subependymal neurons and some larger ones. Only in the p. medialis of the Atlantic salmon are large cells present. In both species the most prominent part is the p. lateralis, which consists solely of large cells. Cells situated between the p. medialis and the p. lateralis are grouped in the p. ventrolateralis. It was impossible to trace the axons originating in the NLT, since the cyto- and axoplasm could not be stained specifically. The structure of the NPO and NLT in the two salmonid species is compared with that of other teleosts.

Animals↗
PubMed1982

Differentiation of soluble proteins in cataracts caused by deficiencies of methionine, riboflavin or zinc in diets fed to Atlantic salmon, Salmo salar, rainbow trout, Salmo gairdneri, and lake trout, Salvelinus namaycush.

Water soluble extracts from cataractous and normal salmonid lenses were subjected to thin-layer isoelectric focusing. The cataracts resulted from deficiencies of specific nutrients in diets fed to three species of salmonids as follows: (1) rainbow trout (Salmo gairdneri) fed a diet deficient in riboflavin; (2) Atlantic salmon (Salmo salar) fed a diet deficient in methionine; and (3) rainbow trout and lake trout (Salvelinus namaycush) fed a diet deficient in zinc. In all tests, the protein pattern of cataractous lenses differed from that of normal lenses. Each cataract caused by the different dietary deficiencies had a specific pattern of soluble lens proteins. Even though the general patterns of the soluble lens proteins for all three salmonids though the general patterns of the soluble lens proteins for all three salmonids studied were similar, a specific pattern was unique for each of the species.

Animals↗
PubMed2000

Isolation, characterization, and chromosomal location of the tRNA(Met) genes in Atlantic salmon (Salmo salar) and brown trout (Salmo trutta).

This work describes the isolation, characterization, and physical location of the methionine tRNA in the genome of Atlantic salmon (Salmo salar L.) and brown trout (Salmo trutta L.). An Atlantic salmon genomic library was screened using a tRNA(Met) probe from Xenopus laevis. Two cosmid clones containing the Atlantic salmon tRNA(Met) gene were isolated, subcloned and sequenced. The tRNA(Met) was mapped to metaphase chromosomes by fluorescence in situ hybridization (FISH). Chromosomal data indicated that the tDNA of methionine is tandemly repeated in a single locus in both species. Analysis of genomic DNA by Southern hybridization confirmed the tandem organization of this gene.

Animals↗
PubMed1999

The susceptibility of Atlantic salmon (Salmo salar L.) x brown trout (Salmo trutta L.) hybrids to Gyrodactylus salaris Malmberg and Gyrodactylus derjavini Mikailov.

Salmo salar and Salmo trutta co-exist in coastal river systems in Europe and produce hybrids with little loss of viability or growth. This report describes the susceptibility of pure full-sibs of S. salar and S. trutta and their reciprocal half-sib hybrids to their respective gyrodactylids, Gyrodactylus salaris and Gyrodactylus derjavini. The pure-bred salmon and trout, and half-sib hybrids, were produced using eggs and sperm from wild anadromous S. salar (River Alta stock, North Norway) and wild anadromous S. trutta (River Fossbekk stock, Southwest Norway). Infections were initiated by exposing experimental fishes (0+) to S. salar naturally infected with G. salaris (River Lierelva strain) or S. trutta naturally infected with G. derjavini (River Sandvikselva strain). Fishes were then kept individually isolated under standardized conditions at 12 degrees C. Pure-bred S. salar were susceptible but frequently mounted a response to G. salaris without eliminating the infection, whereas pure-bred S. trutta were innately resistant to this species. Pure-bred S. trutta ranged from innately resistant to susceptible to G. derjavini but later most of the susceptible trout mounted a host response to G. derjavini. Pure-bred S. salar were also susceptible to this species, although parasite population growth rates were reduced and a host response frequently appeared eliminating G. derjavini. The abundance of both gyrodactylids was lower on the hybrids than on their respective pure-bred natural hosts, and a parental sire- and dam-influence on the resistance of hybrids was observed. When the sire was S. salar, the susceptibility of hybrids to G. salaris was similar to that of pure S. trutta; when the dam was S. salar both innately resistant, intermediately susceptible and responding individuals were present. In the case of G. derjavini, when the sire was S. trutta, infections on hybrids were similar to those on pure S. salar; when the dam was S. trutta, an increased level of susceptibility was observed. The present results provide evidence that: (1) Norwegian salmon stocks are variable in their susceptibility/resistance, with some fish able to control S. salaris infections; (2) trout stocks are innately resistant to G. salaris; (3) individual trout show a spectrum in susceptibility/resistance to G. derjavini, ranging from innate resistance through slightly susceptible to highly susceptible but with acquired resistance controlling infection; (4) although G. derjavini infections grow poorly on salmon, this host stock is susceptible to the parasite, but can limit infection by a host reaction; (5) susceptibility/resistance traits to gyrodactylids are genetically controlled and resistance can be transferred as a dominant trait through interspecific crosses between different salmonids; (6) interspecific hybrids between susceptible and resistant salmonids have a pattern of susceptibility to gyrodactylids intermediate to that of the parents; (7) resistance to gyrodactylids may be controlled by relatively few genes in salmonids; (8) epidemiologically, hybrids may act as a reservoir for gyrodactylids, may support a wider diversity of species than either parent and may disseminate gyrodactylids of both host species.

Animals↗
PubMed2000

Ventricular hypoplasia in farmed Atlantic salmon Salmo salar.

Atlantic salmon Salmo salar L. parr and pre-smolts from 2 Norwegian hatcheries showed reduced weight gain, abnormal behaviour and signs of circulatory disturbances. Necropsy revealed conspicuous fat deposits around the heart to be the most consistent finding. Furthermore, the ventricle/atrium ratio was altered, with the size of the ventricle significantly smaller than normal in affected fish. Histology showed poor development or absence of the outer, compact myocardium, large numbers of fat cells and melanomacrophages in the epicardium, fibrosis, and inflammation of the compactum/spongiosum interphase. Nuclei of the inner spongious myocardium showed signs of compensatory hypertrophy. The cause(s) of this malformation is(are) unknown, but a high prevalence of other malformations in fish from the same population indicates high temperature during incubation of the eggs as a possible aetiology.

Animals↗
PubMed1999

Absence of vertical transmission of infectious salmon anemia virus (ISAV) from individually infected Atlantic salmon Salmo salar.

Atlantic salmon Salmo salar L. eggs were collected from grilse that were individually identified as ISAV-positive based on the detection of pathogen in ovarian fluid by RT-PCR. The eggs were fertilised, disinfected and reared under quarantine conditions. To address the possibility of vertical transmission, fertilised eggs, alevins and parr were screened for the virus by SHK-1 cell culture and RT-PCR. In addition, ISAV-negative parr were injected with homogenates of potentially infected eyed eggs. ISAV was not detected in eyed eggs, alevins or parr. No mortalities occurred among fish injected with the egg homogenates. These observations suggest the absence of a vertical transmission route for ISAV infection.

Anemia↗
PubMed2004

Dexamethasone treatment affects skin mucous cell density in Gyrodactylus derjavini infected Salmo salar.

Atlantic salmon, Salmo salar, is normally rather refractive to infection with the ectoparasitic monogenean Gyrodactylus derjavini but dexamethasone treatment of the host increases the susceptibility. The causative mechanisms were elucidated in this work. Groups of Atlantic salmon were treated by intra-peritoneal dexamethasone injections and subsequently infected with G. derjavini. It was shown that both the infection level and the mucous cell density of caudal and pelvic fins were affected by the treatment. Significantly higher mucous cell densities were found on infected and treated fish whereas non-infected and treated fish showed no significant elevation of cell density. This suggests that mucous cell discharge elicited by infection is inhibited by the drug. The association with elevated parasite counts in these fish can be explained either by decreased anti-parasitic mucus action or by parasite predilection for intact mucous cells.

Animals↗
PubMed2001

Infectious hematopoietic necrosis virus antibody profiles in naturally and experimentally infected Atlantic salmon Salmo salar.

Atlantic salmon Salmo salar naturally and experimentally exposed to infectious hematopoietic necrosis virus (IHNV) in British Columbia, Canada, developed antibodies against the virus. More than 50% of the fish exposed to IHNV remained seropositive for several months after the IHN epizootic had subsided. The virus itself could not be detected in asymptomatic fish once the fish had recovered from IHN. The persistence of IHNV-specific antibodies in a large percentage of Atlantic salmon, from 4 different populations that survived an outbreak of IHN, and the lack of IHNV-specific antibodies in fish with no history of the disease, suggests that serology may be a useful tool for determining previous exposure to the virus. It may be important to determine whether Atlantic salmon have been infected with IHNV because, although the virus is difficult to detect in asymptomatic fish, an incidental finding suggests it may persist in a small number of fish after the outbreak has subsided. Furthermore, the presence of seropositive fish would be an indication that the virus may be enzootic at a farm, and such information would thus aid producers with stocking decisions.

Animals↗
PubMed2001

Effects of subchronic exposure to aluminium in acidic water on bioenergetics of Atlantic salmon (Salmo salar).

Atlantic salmon (Salmo salar) were exposed for 36 days to water from the acidified (pH 5.2) Fossbekk River (Norway) with 50 micro x L(-1) of aluminium (Al) added as AlCl(3), or to circumneutral water (pH 6.6) from Ims River (Norway). Food consumption, cardiac output, swimming activity, and growth rate were measured to determine the effects of sublethal levels of Al in acidic water on the bioenergetics of the fish. Food consumption was reduced in acidic water and Al during the first 12 days, but was not significantly different from the control group during the rest of the exposure. A significant decrease in body weight was concomitant with the reduction in food consumption. The fish also kept losing weight during the rest of the exposure despite the return of their appetite to normal. Cardiac output of the fish exposed to acidic water and Al was not significantly different from the control group after 36 days of exposure. Swimming activity remained significantly elevated throughout the exposure to acidic water and Al. These results indicate that sublethal levels of Al can alter the energy budget of Atlantic salmon living in acidified surface waters.

Aluminum↗
PubMed2004

The effect of various metals on Gyrodactylus salaris (Platyhelminthes, Monogenea) infections in Atlantic salmon (Salmo salar).

Atlantic salmon (Salmo salar) parr (age 0+), infected by the ectoparasite Gyrodactylus salaris, were exposed to aqueous aluminium (Al), copper (Cu), zinc (Zn), iron (Fe) and manganese (Mn), at 4 different concentrations. There was a negative correlation between G. salaris infections and metal concentrations in both Zn- and Al-exposed salmon. In the Zn-experiment, all 4 concentrations tested caused a decrease in the G. salaris infections, while in the Al-experiment the G. salaris infection did not decline at the lowest concentration. The number of G. salaris increased continuously during the experiments in all control groups, and in all groups exposed to Cu, Fe and Mn. At the highest concentration, however, copper seemed to impair the growth of G. salaris infection. The results show that aqueous Al and Zn are environmental factors of importance controlling the distribution and abundance of the pathogen G. salaris. Other pollutants might also have an influence on the occurrence of G. salaris. Finally, the results demonstrate that aqueous Al and Zn have a stronger effect on the parasite than on the salmonid host, suggesting that both metals may be used as a pesticide to control ectoparasites such as G. salaris.

Aluminum↗
PubMed1993

Cloning and sequence analysis of cDNAs encoding the MHC class II beta chain in Atlantic salmon (Salmo salar).

Atlantic salmon (Salmo salar) cDNAs encoding the major histocompatibility complex (Mhc-Sasa) class II beta chain were isolated from a leucocyte library by a polymerase chain reaction (PCR) approach. Three different cDNAs (c144, c22, and c157) encoding the entire mature beta chain have been analyzed. Clone c144 differs from clone c157 in 12.6% of the nucleotides in the beta 1-encoding region. The corresponding differences between clones c144 and c22, and clones c22 and c157, are 10.3% and 5.2%, respectively. This variation is, at least in part, most likely attributable to allelism. The similarity indices between the highly conserved beta 2 domains from Atlantic salmon and corresponding sequences from humans (DQ beta), chicken (BL beta), carp (TLAII beta-1), and rainbow trout (O.M. No. 55) are 45%, 40%, 66%, and 97%, respectively. Variable residues in the beta 1 domains from Atlantic salmon correspond with polymorphic sites of beta 1 domains from higher vertebrates. The frequency of substitutions in the beta 1-encoding region exceeds that in the 3'-untranslated (UT) region with several folds, indicating extensive beta 1 polymorphism in Atlantic salmon.

Amino Acid Sequence↗
PubMed1996

Cloning of T-cell antigen receptor beta chain cDNAs from Atlantic salmon (Salmo salar).

Atlantic salmon (Salmo salar) cDNAs encoding the T-cell antigen receptor beta chain (TCRB) were isolated from leukocyte RNA by reverse transcription - polymerase chain reaction (RT-PCR). Twenty-five distinct cDNA fragments covering the variable (V) - diversity (D) - joining (J) junction and part of the constant (C) region were characterized; the sequences of which indicate interchangeable V/D/J usage and expression in the context of one TCRBC gene. Full-length TCRBC sequence information was derived from a leukocyte cDNA library. Key residues of the salmon TCRBC region are in good agreement with those of other species. One distinct exception is the absence of the hinge region cysteine residue which is involved in covalent bonding between the alpha and beta chain in mammalian TCRs. As in amphibian and avian species, the salmon TCRBC membrane proximal region is considerably shorter than the mammalian. An octamer sequence (GGACAGGG) very similar to amphibian, avian, and mammalian D sequences could be recognized in the VDJ junctions from salmon. The pattern of VDJ variability also indicates that mechanisms like trimming and addition occur in fish as in higher vertebrates. Compared with mammals, a relatively high frequency (32%) of the VDJ junctions in salmon were out of frame.

Amino Acid Sequence↗
PubMed1993

Dietary sunflower, linseed and fish oils affect phospholipid fatty acid composition, development of cardiac lesions, phospholipase activity and eicosanoid production in Atlantic salmon (Salmo salar).

Atlantic salmon (Salmo salar) post-smolts were fed practical-type diets in which the lipid was supplied either as fish oil (FO), sunflower oil (SFO) or linseed oil (LO) for 12 weeks. In general, the heart phospholipids from SFO-fed fish had increased 18:2n-6, 20:2n-6, 20:3n-6 and 20:4n-6 but decreased 20:5n-3 compared to both other dietary treatments. This was reflected in a decreased n-3/n-6 polyunsaturated fatty acid (PUFA) ratio and an increased 20:4n-6/20:5n-3 or eicosanoid precursor ratio in SFO-fed fish. While heart phospholipids of fish fed LO had increased levels of 18:2n-6, 20:2n-6 and 20:3n-6 compared to fish fed FO, 20:4n-6 levels were reduced, although only significantly in phosphatidylcholine (PC). Dietary-induced changes in phospholipid fatty acid compositions of blood leucocytes were similar to those in heart, although fish fed LO had increased 20:5n-3 compared to fish fed FO. Thromboxane B2 (TXB2) produced by stimulated blood cells was reduced in fish fed LO compared to those fed SFO. Prostaglandin E2 (PGE2) production was reduced in LO-fed fish compared to both other dietary treatments. Fish fed LO had reduced PC in heart membranes compared to the other two dietary treatments, resulting in a ratio of PC:PE (phosphatidylethanolamine) less than unity. Fish fed SFO developed a marked cardiac histopathology which, while present in FO-fed fish albeit in a less severe form, was virtually absent in fish fed LO. Fish fed SFO had increased heart phospholipase A activity compared to those given either FO or LO.

Animals↗
PubMed1996

Dietary lipid affects phospholipid fatty acid compositions, eicosanoid production and immune function in Atlantic salmon (Salmo salar).

Atlantic salmon (Salmo salar) post-smolts were fed diets containing either Fosol (FO), a North Sea fish oil, sunflower oil (SO), linseed oil (LO) or Marinol K (MO), a southern hemisphere fish oil rich in 20:5(n-3) for 12 weeks. A macrophage-enriched leucocyte preparation was obtained from head kidney and the fatty acid compositions of the individual membrane phospholipids measured. In general phospholipids from SO- and LO-fed fish had increased 18:2(n-6), 20:2(n-6) and 20:3(n-6) compared to the fish oil treatments while LO-fed fish had lower 20:4(n-6) than any other dietary treatment. Fish fed LO also had increased 18:3(n-3), 18:4(n-3), 20:3(n-3) and 20:4(n-3). The 20:5(n-3) content of kidney macrophage-enriched leucocyte phospholipids was highest in MO-fed fish followed by FO- and LO-fed fish with the lowest level in fish fed SO. The overall effect on the ratio of eicosanoid precursors, 20:4/20:5, showed the highest value in SO-fed fish and the lowest in fish fed LO. Production of LTB5 by kidney macrophage-enriched leucocytes stimulated with A23187 was highest in MO-fed fish and lowest in those fed SO. Production of LTB4 was greatest in SO-fed fish and lowest in fish fed LO. Serum Ig levels were significantly affected by dietary treatment with highest values in fish fed FO and SO and lowest in fish fed MO and LO.

Animals↗
PubMed1999

Time course tissue distribution of infectious salmon anaemia virus in experimentally infected Atlantic salmon Salmo salar.

Atlantic salmon Salmo salar L. were injected intraperitoneally with infectious salmon anaemia virus (ISAV)-infective tissue homogenate to clarify the tissue distribution of ISAV in a time course study. Fish were sampled at 11 different intervals between 1 and 40 d post-infection (p.i.) and mid-kidney, head kidney, liver, spleen, intestine, gills, muscle and heart were tested for the presence of ISAV by reverse transcriptase polymerase chain reaction (RT-PCR). The results showed that during a disease outbreak, ISAV is present in most organs. It was possible to detect ISAV at all sampling times in at least 1 of the fish examined. However, for the first 8 d p.i. positive RT-PCR results were predominantly found in samples from the head kidney and mid-kidney. Fish giving positive samples after Day 13 p.i. were RT-PCR positive in most organs. These results indicated that between Days 8 to 13 p.i. considerable replication of the virus occurred, combined with wide tissue dissemination.

Anemia↗
PubMed2005

N-Terminal Sequence and Main Characteristics of Atlantic Salmon (Salmo salar) Albumin.

Atlantic salmon (Salmo salar) serum albumin was purified from plasma and its N-terminal sequence determined. Atlantic salmon albumin is the predominant plasma protein, negatively charged, at pH 8.6. Albumin was purified to >95% purity which yielded a single band on SDS-PAGE and agarose gel electrophoresis. The molecular weight of the purified albumin was approximately 6,5 kDa. The N-terminal sequence of Atlantic chinook salmon albumin was consistent with that predicted from its previously determined cDNA sequence and was identical to that of salmon (Oncorhynchus tshawytscha) albumin through the first 15 residues. However, the fact that the actual N-terminus was different from that predicted from cDNA sequence indicates that Atlantic salmon albumin, like chinook salmon albumin, lacks a propeptide.

Amino Acid Sequence↗