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Abstract Cleaner fish (wrasse and lumpfish) are now used as a biological control for sea lice on commercially farmed salmon in Europe and Canada. The use of cleaner fish is an environmental and efficient alternative for removal of sea... more
Abstract Cleaner fish (wrasse and lumpfish) are now used as a biological control for sea lice on commercially farmed salmon in Europe and Canada. The use of cleaner fish is an environmental and efficient alternative for removal of sea lice. In order to remove lice efficiently, the cleaner fish need to be healthy and the welfare of the cleaner fish is of major importance. Farmed cleaner fish are preferred due to better disease control through vaccination and screening programs. Strict regulations for harvesting wild-caught wrasse are needed to ensure their long-term vitality. In this chapter, the current knowledge of cleaner fish management, applications, and challenges, including brood stock, hatchery, transport, and deployment, in net pens has been summarized. Furthermore, this chapter gives an overview of diseases, antibacterial treatment and vaccination, and what is known about nutrition requirement and health status. Finally, parameters useful for monitoring the health status of the cleaner fish and ethical considerations are discussed.
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BackgroundBoth bacterial and viral diseases are a major threat to farmed fish. As the antiviral immune mechanisms in lumpfish (Cyclopterus lumpus L.) are poorly understood, lumpfish leukocytes were stimulated with poly(I:C), a synthetic... more
BackgroundBoth bacterial and viral diseases are a major threat to farmed fish. As the antiviral immune mechanisms in lumpfish (Cyclopterus lumpus L.) are poorly understood, lumpfish leukocytes were stimulated with poly(I:C), a synthetic analog of double stranded RNA, which mimic viral infections, and RNA sequencing was performed.MethodsTo address this gap, we stimulated lumpfish leukocytes with poly(I:C) for 6 and 24 hours and did RNA sequencing with three parallels per timepoint. Genome guided mapping was performed to define differentially expressed genes (DEGs).ResultsImmune genes were identified, and transcriptome-wide analyses of early immune responses showed that 376 and 2372 transcripts were significantly differentially expressed 6 and 24 hours post exposure (hpe) to poly(I:C), respectively. The most enriched GO terms when time had been accounted for, were immune system processes (GO:0002376) and immune response (GO:0006955). Analysis of DEGs showed that among the most highly ...
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Vibrionaceae infections are a major obstacle for marine larviculture; however, little is known about virulence differences of Vibrio strains. The virulence of Vibrio strains, mostly isolated from vibriosis outbreaks in farmed fish, was... more
Vibrionaceae infections are a major obstacle for marine larviculture; however, little is known about virulence differences of Vibrio strains. The virulence of Vibrio strains, mostly isolated from vibriosis outbreaks in farmed fish, was tested in larval challenge trials with cod (Gadus morhua), turbot (Scophthalmus maximus) and halibut (Hippoglossus hippoglossus) using a multiwell dish assays with single‐egg/larvae cultures. The strains differed significantly in virulence as some caused a high mortality of larva reaching 100% mortality after a few days, while others had no or only marginal effects on survival. Some Vibrio strains were pathogenic in all of the larva species, while some caused disease only in one of the species. Twenty‐nine of the Vibrio anguillarum strains increased the mortality of larvae from at least one fish species; however, pathogenicity of the strains differed markedly. Other Vibrio species had no or less pronounced effects on larval mortalities. Iron uptake has been related to V. anguillarum virulence; however, the presence or absence of the plasmid pJM1 encoding anguibactin did not correlate with virulence. The genomes of V. anguillarum were compared (D. Castillo, P.W. D'Alvise, M. Middelboe & L. Gram, unpublished data) and most of the high‐virulent strains had acquired virulence genes from other pathogenic Vibrio.
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Lumpfish is a novel farmed species used as cleaner fish for the removal of lice from farmed salmon. As often with new, farmed species, there are challenges with bacterial infections. The frequency of prescription of antibiotic agents to... more
Lumpfish is a novel farmed species used as cleaner fish for the removal of lice from farmed salmon. As often with new, farmed species, there are challenges with bacterial infections. The frequency of prescription of antibiotic agents to lumpfish is increasing, despite the lack of knowledge about appropriate doses, duration of treatment and application protocols for the various antibacterial agents. In the current study, we have tested the effect of medicated feed with florfenicol (FFC), oxolinic acid (OA) and flumequine (FLU) on lumpfish experimentally challenged with Vibrio anguillarum, atypical Aeromonas salmonicida and Pasteurella atlantica. We found that all three antibacterial agents efficiently treated lumpfish with vibriosis using 10 and 20 mg kg−1 day−1 of FFC, 25 mg kg−1 day−1 of OA and 25 mg kg−1 day−1 FLU, whereas only FFC (20 mg kg−1 day−1) had good effect on lumpfish with pasteurellosis. None of the antibacterial agents were efficient to treat lumpfish with atypical fur...
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Farmed lumpfish (Cyclopterus lumpus) are commonly used as cleaner fish in the salmonid aquaculture industry, but a knowledge gap exists with regards to their body density. Filling this knowledge gap is of importance, as the lumpfish has... more
Farmed lumpfish (Cyclopterus lumpus) are commonly used as cleaner fish in the salmonid aquaculture industry, but a knowledge gap exists with regards to their body density. Filling this knowledge gap is of importance, as the lumpfish has no swim bladder and thus relies on alternative methods for buoyancy, i.e., the body density difference between the fish and its surroundings. The aims of this study were to measure the body density of lumpfish and investigate the correlation between body density and different operational welfare indicators. A total of 138 lumpfish were sampled at five different aquaculture sites situated in the Faroe Islands. Weight in water and air was measured, body density was calculated, and operational welfare was assessed. The average body density of the juvenile lumpfish was 1.030 g mL−1. Fulton’s K, stomach score, and length were negatively correlated to body density, while the hepatosomatic index was positively correlated to body density. Liver colour was co...
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Hydrolytic deamination of cytosine to uracil in cellular DNA is a major source of C-to-T transition mutations if uracil is not repaired by the DNA base excision repair (BER) pathway. Since deamination increases rapidly with temperature,... more
Hydrolytic deamination of cytosine to uracil in cellular DNA is a major source of C-to-T transition mutations if uracil is not repaired by the DNA base excision repair (BER) pathway. Since deamination increases rapidly with temperature, hyperthermophiles, in particular, are expected to succumb to such damage. There has been only one report of crenarchaeotic BER showing strong similarities to that in most eukaryotes and bacteria for hyperthermophilic Archaea . Here we report a different type of BER performed by extract prepared from cells of the euryarchaeon Archaeoglobus fulgidus . Although immunodepletion showed that the monofunctional family 4 type of uracil-DNA glycosylase (UDG) is the principal and probably only UDG in this organism, a β-elimination mechanism rather than a hydrolytic mechanism is employed for incision of the abasic site following uracil removal. The resulting 3′ remnant is removed by efficient 3′-phosphodiesterase activity followed by single-nucleotide insertion...
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<b>Copyright information:</b>Taken from "Stimulation of MCM helicase activity by a Cdc6 protein in the archaeon "Nucleic Acids Research 2006;34(21):6337-6344.Published online 15 Nov 2006PMCID:PMC1669734.© 2006 The... more
<b>Copyright information:</b>Taken from "Stimulation of MCM helicase activity by a Cdc6 protein in the archaeon "Nucleic Acids Research 2006;34(21):6337-6344.Published online 15 Nov 2006PMCID:PMC1669734.© 2006 The Author(s) () Two-hybrid analysis of the interactions between MCM and the Cdc6 proteins were performed as described in Materials and Methods. The left panel shows an outline of the plate. 1, pDBLeu-TaMCM and pPC86; 2, pDBLeu-TaCdc6-1 and pPC86, 3, pDBLeu-TaCdc6-2 and pPC86; 4, pDBLeu-TaCdc6-2 and pPC86-TaMCM; 5, pDBLeu-TaCdc6-1 and pPC86-TaMCM; 6, pDBLeu-TaMCM and pDBLeu-TaMCM. Center panel, CSM plate minus Leu, Trp and His; Right panel, CSM plate minus Leu, Trp and His containing 10 mM 3-amino-1,2,4-triazole (3AT). () Protein pull-down analysis of the interactions between MCM and the Cdc6 proteins were performed as described in Material and Methods by binding S-MCM and His-tagged Cdc6-1 or -2 protein followed by absorption to Ni-column. Lane 1, 20% of the S-MCM used for each binding reaction; lane 2, S-MCM alone; lane 3, S-MCM and His-Cdc6-1; lane 4, S-MCM and His-Cdc6-2. The percent of the input S-MCM retained on the column is noted below each lane.
Replicative DNA helicases are ring-shaped hexam- ers that play an essential role in chromosomal DNA replication. They unwind the two strands of the duplex DNA and provide the single-stranded (ss) DNA substrate for the polymerase. The... more
Replicative DNA helicases are ring-shaped hexam- ers that play an essential role in chromosomal DNA replication. They unwind the two strands of the duplex DNA and provide the single-stranded (ss) DNA substrate for the polymerase. The minichro- mosome maintenance (MCM) proteins are thought to function as the replicative helicases in eukarya and archaea. The proteins of only a few archaeal
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Francisella noatunensis subsp. noatunensis, causing granulomatosis in cod, has been shown to reside within cod immune cells, mainly within monocytes and macrophages. In the present study, we analysed the ability of the bacterium to... more
Francisella noatunensis subsp. noatunensis, causing granulomatosis in cod, has been shown to reside within cod immune cells, mainly within monocytes and macrophages. In the present study, we analysed the ability of the bacterium to replicate within adherent cells isolated from head kidney by in vitro infection of leucocytes. Two different technical approaches for flow cytometry analyses were performed for detection of intracellular bacteria. The presence of the wild type was assessed after identification by intracellular binding of specific antibodies to the pathogen. The other way was to use green fluorescent protein (GFP) transformed bacterium for infection studies allowing direct measurements of fluorescence from infected cells. By both methods we found an increase in fluorescence in infected cells, verifying bacterial replication, both after 4 and 28 h post infection in leucocytes isolated from head kidney (HKL). The GFP transformed bacterium was similar to the wild type in growth and infectivity pattern, showing that it can be a valuable tool for further studies of infection routes and pathology. Further, F. noatunensis subsp. noatunensis was found to inhibit respiratory burst activity, a potent pathogen killing mechanism, in cod leucocytes, but not in such cells from salmon. Our findings may indicate that inhibition of respiratory burst during Francisella infection is a key to its intracellular existence. This strategy seems to be conserved through evolution as it is also observed during infections in higher vertebrates caused by bacteria within the Francisella genus. The results presented here, showing the intracellular existence of Francisella, its replication within leucocytes and the inhibitory effect on respiratory burst, strongly support that these factors contribute to disease and pathology in infected cod. The intracellular replication shown in the present study might contribute to explain the problems of obtaining protective vaccines against Francisella and effective antibiotic treatment of infected fish.
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Objective: Suicide is a devastating public health problem, and research indicates that people with prior attempts are at the greatest risk of completing suicide, followed by persons with depression and other major mental and substance use... more
Objective: Suicide is a devastating public health problem, and research indicates that people with prior attempts are at the greatest risk of completing suicide, followed by persons with depression and other major mental and substance use conditions. Because there has ...
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Research Interests: Biology, DNA damage, DNA repair, Medicine, Macromolecular X-Ray Crystallography, and 11 moreBiological Sciences, Crystal structure, High Resolution, Amino Acid Sequence, Base Sequence, Site-directed Mutagenesis, Base Excision Repair, Molecular Structure, Molecular Sequence Data, Archaeoglobus fulgidus, and Medical and Health Sciences
Research Interests: Engineering, Physics, Chemistry, Stem Cells, Flow Cytometry, and 15 moreBiology, Medicine, Multidisciplinary, Dendritic Cells, Cell Differentiation, Animals, PLoS one, Fluorescent Antibody Technique, Salmo salar, Immunoglobulins, Phagocytes, Respiratory Burst, Immunoblotting, Acid Phosphatase, and real time polymerase chain reaction
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Research Interests: Immunology, Flow Cytometry, Fluorescence Microscopy, Confocal Microscopy, Cell line, and 13 moreAnimals, Monoclonal Antibodies, Dendritic cell, Atlantic Salmon, Neutrophils, Fluorescent Antibody Technique, Optometry and Ophthalmology, Salmo salar, Monoclonal Antibody, Rabbits, Immunostaining, Immunoglobulin, and Peripheral blood
Sterile triploid fish are being used in aquaculture to prevent early unwanted sexual maturation and the genetic interaction between wild and cultured fish; however, triploid fish are typically considered to be more susceptible to disease... more
Sterile triploid fish are being used in aquaculture to prevent early unwanted sexual maturation and the genetic interaction between wild and cultured fish; however, triploid fish are typically considered to be more susceptible to disease than diploid counterparts. Proportions of leucocytes from the head kidney and peripheral blood were identified using monoclonal antibodies and flow cytometry in triploid and diploid, vaccinated and unvaccinated, out-of-season (0+) and 1+ Atlantic salmon (Salmo salar L.) three weeks post seawater transfer. Triploid 1+ fish were significantly (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05) heavier than diploid fish at the time of sampling, whereas triploid 0+ had a significantly lower condition factor than diploids. Ploidy had a significant effect on the proportion of B-cells in the blood of both 0+ and 1+ fish, and the head kidney of 1+ fish, with triploids having lower proportions of B-cells to diploids in both smolt groups. In addition, a significant ploidy×vaccination interaction effect was observed in the response of neutrophils in the blood (vaccinated diploids had a higher mean proportion than diploid unvaccinated) and B-cells in the head kidney (in vaccinated fish, triploids had a lower mean proportion than diploids) in 0+ smolts. Vaccination was found to significantly increase the proportion of B-cells in the head kidney of 1+ smolts in both ploidy. Size (fish weight) was positively correlated with neutrophil proportions in 1+ fish. Our findings are discussed in relation to the physiological differences related to ploidy. The results suggest that ploidy as well as smelting regime influences the immune system of Atlantic salmon post-smolts.
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In recent years, use of lumpfish (Cyclopterus lumpus L.) as cleaner-fish to remove sea-lice have been chosen by many salmon farmers in Europe and Canada as an alternative to medical treatment, which has led to large scale production of... more
In recent years, use of lumpfish (Cyclopterus lumpus L.) as cleaner-fish to remove sea-lice have been chosen by many salmon farmers in Europe and Canada as an alternative to medical treatment, which has led to large scale production of lumpfish. At present, there is limited knowledge of how lumpfish respond upon anaesthesia, which anaesthetics and concentrations that are efficient and conditions for euthanasia. We have therefore tested and developed protocols for bath immersion for three commonly used anaesthetics metacaine (Finquel, buffered tricaine methanesulfonate, MS-222 and Tricaine Pharmaq), benzocaine (Benzoak vet) and isoeugenol (Aqui-S), determined concentration for normal and fast anaesthesia and evaluated safety margin for each condition. Also, a behavioral matrix has been developed. We have examined the effect of fish size (10-20 g, 200-400 g and 600-1300 g) and sea water temperature (6°C and 12°C). We found that 200 mg L-1 metacaine is an efficient dose for deep narcos...
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The innate immune responses in lumpfish (Cyclopterus lumpus L.) have been shown to be functional, but little is currently known about the B cells, immunoglobulins or adaptive immune responses in this species. We have used anti-IgM... more
The innate immune responses in lumpfish (Cyclopterus lumpus L.) have been shown to be functional, but little is currently known about the B cells, immunoglobulins or adaptive immune responses in this species. We have used anti-IgM antiserum to isolate B cells and compared them morphologically and functionally with other cell types. The fraction of IgM(+) cells among isolated peripheral blood leukocytes (PBL), head kidney leukocytes (HKL) and spleen leukocytes (SL) was in the range of 40%, 12% and 34%, respectively. The IgM(+) B cells had high phagocytic ability and were the predominant phagocytes in blood with higher capacity than IgM(+) B cells in HKL. Interestingly, among PBL, the most potent phagocytes were, in addition to monocytes, some small agranular uncharacterized IgM(-) cells. The IgM(+) B cells were positive for acid phosphatases (AcP), but negative for myeloperoxidase (MPO). Neutrophils were positive for MPO, while monocytes/macrophages and dendritic-like cells stained negatively. Monocytes/macrophages and the small, agranular IgM(-) cells stained most strongly positive for AcP corresponding to their high phagocytic capacity. Further, the ability to produce specific antibodies upon immunization verified adaptive immunity in the species. The high proportion of phagocytic IgM(+) B cells and their phagocytic ability indicate a significant role of phagocytic B cells in lumpfish innate immunity. The present analyses also give strong indications that vaccination and immunostimulation of farmed lumpfish can be used to prevent disease and mortality caused by pathogenic organisms.
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In DNA replication studies, the mechanism for regulation of the various steps from initiation to elongation is a crucial subject to understand cell cycle control. The eukaryotic minichromosome maintenance (MCM) protein complex is... more
In DNA replication studies, the mechanism for regulation of the various steps from initiation to elongation is a crucial subject to understand cell cycle control. The eukaryotic minichromosome maintenance (MCM) protein complex is recruited to the replication origin by Cdc6 and Cdt1 to form the pre-replication complex, and participates in forming the CMG complex formation with Cdc45 and GINS to work as the active helicase. Intriguingly, Thermoplasma acidophilum, as well as many other archaea, has only one Gins protein homolog, contrary to the heterotetramer of the eukaryotic GINS made of four different proteins. The Gins51 protein reportedly forms a homotetramer (TaGINS) and physically interacts with TaMCM. In addition, TaCdc6-2, one of the two Cdc6/Orc1 homologs in T. acidophilum reportedly stimulates the ATPase and helicase activities of TaMCM in vitro. Here, we found a reaction condition, in which TaGINS stimulated the ATPase and helicase activities of TaMCM in a concentration dep...