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Slinning MS, Nthiga TM, Eichner C, Khadija S, Rome LH, Nilsen F, Dondrup M. Major vault protein is part of an extracellular cement material in the Atlantic salmon louse (Lepeophtheirus salmonis). Sci Rep 2024; 14:15240. [PMID: 38956386 PMCID: PMC11219742 DOI: 10.1038/s41598-024-65683-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 06/24/2024] [Indexed: 07/04/2024] Open
Abstract
Major vault protein (MVP) is the main component of the vault complex, which is a highly conserved ribonucleoprotein complex found in most eukaryotic organisms. MVP or vaults have previously been found to be overexpressed in multidrug-resistant cancer cells and implicated in various cellular processes such as cell signaling and innate immunity. The precise function of MVP is, however, poorly understood and its expression and probable function in lower eukaryotes are not well characterized. In this study, we report that the Atlantic salmon louse expresses three full-length MVP paralogues (LsMVP1-3). Furthermore, we extended our search and identified MVP orthologues in several other ecdysozoan species. LsMVPs were shown to be expressed in various tissues at both transcript and protein levels. In addition, evidence for LsMVP to assemble into vaults was demonstrated by performing differential centrifugation. LsMVP was found to be highly expressed in cement, an extracellular material produced by a pair of cement glands in the adult female salmon louse. Cement is important for the formation of egg strings that serve as protective coats for developing embryos. Our results imply a possible novel function of LsMVP as a secretory cement protein. LsMVP may play a role in structural or reproductive functions, although this has to be further investigated.
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Affiliation(s)
- Malene Skuseth Slinning
- Sea Lice Research Centre (SLRC), Department of Biological Sciences, University of Bergen, Pb. 7803, 5020, Bergen, Norway
| | - Thaddaeus Mutugi Nthiga
- Sea Lice Research Centre (SLRC), Department of Biological Sciences, University of Bergen, Pb. 7803, 5020, Bergen, Norway
| | - Christiane Eichner
- Sea Lice Research Centre (SLRC), Department of Biological Sciences, University of Bergen, Pb. 7803, 5020, Bergen, Norway
| | - Syeda Khadija
- Department of Biological Chemistry, David Geffen School of Medicine and the California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Leonard H Rome
- Department of Biological Chemistry, David Geffen School of Medicine and the California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Frank Nilsen
- Sea Lice Research Centre (SLRC), Department of Biological Sciences, University of Bergen, Pb. 7803, 5020, Bergen, Norway
| | - Michael Dondrup
- SLRC, Computational Biology Unit (CBU), Department of Informatics, University of Bergen, Pb. 7803, 5020, Bergen, Norway.
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Dalvin S, Eichner C, Dondrup M, Øvergård AC. Roles of three putative salmon louse (Lepeophtheirus salmonis) prostaglandin E 2 synthases in physiology and host-parasite interactions. Parasit Vectors 2021; 14:206. [PMID: 33874988 PMCID: PMC8056522 DOI: 10.1186/s13071-021-04690-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 03/16/2021] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND The salmon louse (Lepeophtheirus salmonis) is a parasite of salmonid fish. Atlantic salmon (Salmo salar) exhibit only a limited and ineffective immune response when infested with this parasite. Prostaglandins (PGs) have many biological functions in both invertebrates and vertebrates, one of which is the regulation of immune responses. This has led to the suggestion that prostaglandin E2 (PGE2) is important in the salmon louse host-parasite interaction, although studies of a salmon louse prostaglandin E2 synthase (PGES) 2 gene have not enabled conformation of this hypothesis. The aim of the present study was, therefore, to characterize two additional PGES-like genes. METHODS Lepeophtheirus salmonis microsomal glutathione S-transferase 1 like (LsMGST1L) and LsPGES3L were investigated by sequencing, phylogenetics, transcript localization and expression studies. Moreover, the function of these putative PGES genes in addition to the previously identified LsPGES2 gene was analyzed in double stranded (ds) RNA-mediated knockdown (KD) salmon louse. RESULTS Analysis of the three putative LsPGES genes showed a rather constitutive transcript level throughout development from nauplius to the adult stages, and in a range of tissues, with the highest levels in the ovaries or gut. DsRNA-mediated KD of these transcripts did not produce any characteristic changes in phenotype, and KD animals displayed a normal reproductive output. The ability of the parasite to infect or modulate the immune response of the host fish was also not affected by KD. CONCLUSIONS Salmon louse prostaglandins may play endogenous roles in the management of reproduction and oxidative stress and may be a product of salmon louse blood digestions.
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Affiliation(s)
- Sussie Dalvin
- Institute of Marine Research, SLCR-Sea Lice Research Centre, Nordnes, P. box 1870, 5817, Bergen, Norway
| | - Christiane Eichner
- Department of Biological Sciences, SLCR-Sea Lice Research Centre, University of Bergen, P. box 7803, 5020, Bergen, Norway
| | - Michael Dondrup
- Department of Informatics, SLRC-Sea Lice Research Centre, University of Bergen, P. box 7803, 5020, Bergen, Norway
| | - Aina-Cathrine Øvergård
- Department of Biological Sciences, SLCR-Sea Lice Research Centre, University of Bergen, P. box 7803, 5020, Bergen, Norway.
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Heggland EI, Dondrup M, Nilsen F, Eichner C. Host gill attachment causes blood-feeding by the salmon louse (Lepeophtheirus salmonis) chalimus larvae and alters parasite development and transcriptome. Parasit Vectors 2020; 13:225. [PMID: 32375890 PMCID: PMC7201535 DOI: 10.1186/s13071-020-04096-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 04/24/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Blood-feeding is a common strategy among parasitizing arthropods, including the ectoparasitic salmon louse (Lepeophtheirus salmonis), feeding off its salmon host's skin and blood. Blood is rich in nutrients, among these iron and heme. These are essential molecules for the louse, yet their oxidative properties render them toxic to cells if not handled appropriately. Blood-feeding might therefore alter parasite gene expression. METHODS We infected Atlantic salmon with salmon louse copepodids and sampled the lice in two different experiments at day 10 and 18 post-infestation. Parasite development and presence of host blood in their intestines were determined. Lice of similar instar age sampled from body parts with differential access to blood, namely from gills versus lice from skin epidermis, were analysed for gene expression by RNA-sequencing in samples taken at day 10 for both experiments and at day 18 for one of the experiments. RESULTS We found that lice started feeding on blood when becoming mobile preadults if sitting on the fish body; however, they may initiate blood-feeding at the chalimus I stage if attached to gills. Lice attached to gills develop at a slower rate. By differential expression analysis, we found 355 transcripts elevated in lice sampled from gills and 202 transcripts elevated in lice sampled from skin consistent in all samplings. Genes annotated with "peptidase activity" were among the ones elevated in lice sampled from gills, while in the other group genes annotated with "phosphorylation" and "phosphatase" were pervasive. Transcripts elevated in lice sampled from gills were often genes relatively highly expressed in the louse intestine compared with other tissues, while this was not the case for transcripts elevated in lice sampled from skin. In both groups, more than half of the transcripts were from genes more highly expressed after attachment. CONCLUSIONS Gill settlement results in an alteration in gene expression and a premature onset of blood-feeding likely causes the parasite to develop at a slower pace.
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Affiliation(s)
- Erna Irene Heggland
- Department of Biological Sciences and Sea Lice Research Centre (SLRC), University of Bergen, Bergen, Norway
| | - Michael Dondrup
- Department of Informatics and Sea Lice Research Centre (SLRC), University of Bergen, Bergen, Norway
| | - Frank Nilsen
- Department of Biological Sciences and Sea Lice Research Centre (SLRC), University of Bergen, Bergen, Norway
| | - Christiane Eichner
- Department of Biological Sciences and Sea Lice Research Centre (SLRC), University of Bergen, Bergen, Norway.
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Michaud DR, Poley JD, Fast MD. Sex-biased gene expression and evolution of candidate reproductive transcripts in adult stages of salmon lice (Lepeophtheirus salmonis). Facets (Ott) 2019. [DOI: 10.1139/facets-2018-0016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The salmon louse Lepeophtheirus salmonis (Krøyer 1837) displays numerous sexually dimorphic characteristics. Insights into their underlying molecular components have only recently been explored, which serve to better understand both the basic biology of the louse, associated impacts on drug sensitivity, and evolution of resistance. Expression of 16 L. salmonis genes putatively involved in sexual dimorphism and reproduction were used to determine differences between sexes and better understand responses to mating using RT-qPCR of pre-adult and adult lice. Analysis of these genes revealed the dynamic nature of sex-biased expression across stages. However, female reception of a spermatophore did not appear to impact the expression of these particular genes. Furthermore six of these transcripts and 84 others identified previously in a large-scale louse transcriptomics experiment were used to estimate differences in evolutionary rates and codon-usage bias of sex-related genes using phylogenetic analysis by maximum likelihood (PAML) and codonW. Results suggest male-biased genes are evolving at significantly greater rates than female-biased and unbiased genes as evidenced by higher rates of non-synonymous substitutions and lower codon-usage bias in these genes. These analyses expand our understanding of interactions of sex-biased expression across the pre-adult and adult life stages and provide foundations for better understanding evolutionary differences in sex-biased genes of L. salmonis.
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Affiliation(s)
- Dylan R. Michaud
- Hoplite Research Group, Department of Pathology and Microbiology, Atlantic Veterinary College, UPEI, Charlottetown, PE C1A 4P3, Canada
| | - Jordan D. Poley
- Hoplite Research Group, Department of Pathology and Microbiology, Atlantic Veterinary College, UPEI, Charlottetown, PE C1A 4P3, Canada
- Center for Aquaculture Technologies Canada, 20 Hope Street, Souris PE C0A 2B0, Canada
| | - Mark D. Fast
- Hoplite Research Group, Department of Pathology and Microbiology, Atlantic Veterinary College, UPEI, Charlottetown, PE C1A 4P3, Canada
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Eichner C, Dondrup M, Nilsen F. RNA sequencing reveals distinct gene expression patterns during the development of parasitic larval stages of the salmon louse (Lepeophtheirus salmonis). JOURNAL OF FISH DISEASES 2018; 41:1005-1029. [PMID: 29368347 DOI: 10.1111/jfd.12770] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 11/08/2017] [Accepted: 11/10/2017] [Indexed: 06/07/2023]
Abstract
The salmon louse (Lepeophtheirus salmonis), an ectoparasitic copepod on salmonids, has become a major threat for the aquaculture industry. In search for new drugs and vaccines, transcriptome analysis is increasingly used to find differently regulated genes and pathways in response to treatment. However, the underlying gene expression changes going along with developmental processes could confound such analyses. The life cycle of L. salmonis consists of eight stages divided by moults. The developmental rate of salmon lice on the host is not uniform. Individual- and sex-related differences are found leading to individuals of unlike developmental status at same sampling time point after infection. In this study, we analyse L. salmonis from a time series by RNA sequencing applying a method of separating individuals of different instar age independent of sampling time point. Lice of four stages divided into up to four age groups within the stage were analysed in triplicate (total of 66 samples). Gene expression analysis shows that the method for sorting individuals was successful. Many genes show cyclic expression patterns over the moulting cycles. Overall gene expression differs more between lice of different age within the same stage than between lice of different stage but same instar age.
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Affiliation(s)
- C Eichner
- Sea Lice Research Centre, Department of Molecular Biology, University of Bergen, Bergen, Norway
| | - M Dondrup
- Sea Lice Research Centre, Department of Informatics, University of Bergen, Bergen, Norway
| | - F Nilsen
- Sea Lice Research Centre, Department of Biology, University of Bergen, Bergen, Norway
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Sandlund L, Kongshaug H, Horsberg TE, Male R, Nilsen F, Dalvin S. Identification and characterisation of the ecdysone biosynthetic genes neverland, disembodied and shade in the salmon louse Lepeophtheirus salmonis (Copepoda, Caligidae). PLoS One 2018; 13:e0191995. [PMID: 29401467 PMCID: PMC5798790 DOI: 10.1371/journal.pone.0191995] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 01/14/2018] [Indexed: 11/19/2022] Open
Abstract
The salmon louse is a marine ectoparasitic copepod on salmonid fishes. Its lifecycle consists of eight developmental stages, each separated by a molt. In crustaceans and insects, molting and reproduction is controlled by circulating steroid hormones such as 20-hydroxyecdysone. Steroid hormones are synthesized from cholesterol through catalytic reactions involving a 7,8-dehydrogenase Neverland and several cytochrome P450 genes collectively called the Halloween genes. In this study, we have isolated and identified orthologs of neverland, disembodied and shade in the salmon louse (Lepeophtheirus salmonis) genome. Tissue-specific expression analysis show that the genes are expressed in intestine and reproductive tissue. In addition, levels of the steroid hormones ecdysone, 20-hydroxyecdysone and ponasterone A were measured during the reproductive stage of adult females and in early life stages.
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Affiliation(s)
- Liv Sandlund
- Sea Lice Research Centre, Department of Biological sciences, University of Bergen, Bergen, Norway
- Sea Lice Research Centre, Institute of Marine Research, Bergen, Norway
| | - Heidi Kongshaug
- Sea Lice Research Centre, Department of Biological sciences, University of Bergen, Bergen, Norway
| | - Tor Einar Horsberg
- Sea Lice Research Centre, Norwegian University of Life Sciences, Oslo, Norway
| | - Rune Male
- Sea Lice Research Centre, Department of Biological sciences, University of Bergen, Bergen, Norway
| | - Frank Nilsen
- Sea Lice Research Centre, Department of Biological sciences, University of Bergen, Bergen, Norway
| | - Sussie Dalvin
- Sea Lice Research Centre, Institute of Marine Research, Bergen, Norway
- * E-mail:
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Poley JD, Sutherland BJG, Fast MD, Koop BF, Jones SRM. Effects of the vertically transmitted microsporidian Facilispora margolisi and the parasiticide emamectin benzoate on salmon lice (Lepeophtheirus salmonis). BMC Genomics 2017; 18:630. [PMID: 28818044 PMCID: PMC5561633 DOI: 10.1186/s12864-017-4040-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 08/08/2017] [Indexed: 12/15/2022] Open
Abstract
Background Microsporidia are highly specialized, parasitic fungi that infect a wide range of eukaryotic hosts from all major taxa. Infections cause a variety of damaging effects on host physiology from increased stress to death. The microsporidian Facilispora margolisi infects the Pacific salmon louse (Lepeophtheirus salmonis oncorhynchi), an economically and ecologically important ectoparasitic copepod that can impact wild and cultured salmonids. Results Vertical transmission of F. margolisi was demonstrated by using PCR and in situ hybridization to identify and localize microsporidia in female L. salmonis and their offspring. Spores and developmental structures of F. margolisi were identified in 77% of F1 generation copepods derived from infected females while offspring from uninfected females all tested negative for the microsporidia. The transcriptomic response of the salmon louse to F. margolisi was profiled at both the copepodid larval stage and the pre-adult stage using microarray technology. Infected copepodids differentially expressed 577 transcripts related to stress, ATP generation and structural components of muscle and cuticle. The infection also impacted the response of the copepodid to the parasiticide emamectin benzoate (EMB) at a low dose of 1.0 ppb for 24 h. A set of 48 transcripts putatively involved in feeding and host immunomodulation were up to 8-fold underexpressed in the F. margolisi infected copepodids treated with EMB compared with controls or either stressor alone. Additionally, these infected lice treated with EMB also overexpressed 101 transcripts involved in stress resistance and signalling compared to the other groups. In contrast, infected pre-adult lice did not display a stress response, suggesting a decrease in microsporidian virulence associated with lice maturity. Furthermore, copepodid infectivity and moulting was not affected by the microsporidian infection. Conclusions This study demonstrated that F. margolisi is transmitted vertically between salmon louse generations and that biological impacts of infection differ depending on the stage of the copepod host. The infection caused significant perturbations of larval transcriptomes and therefore must be considered in future studies in which impacts to host development and environmental factors are assessed. Fitness impacts are probably minor, although the interaction between pesticide exposure and microsporidian infection merits further study. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-4040-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jordan D Poley
- Atlantic Veterinary College, University of Prince Edward Island, Department of Pathology & Microbiology, 550 University Ave, Charlottetown, PE, C1A 4P3, Canada
| | - Ben J G Sutherland
- Centre for Biomedical Research, Department of Biology, University of Victoria, 3800 Finnerty Rd, Victoria, BC, V8W 3N5, Canada.,Institut de Biologie Intégrative et des Systèmes (IBIS), Département de biologie, Université Laval, 1030 Avenue de la Medecine, Québec, QC, G1V 0A6, Canada
| | - Mark D Fast
- Atlantic Veterinary College, University of Prince Edward Island, Department of Pathology & Microbiology, 550 University Ave, Charlottetown, PE, C1A 4P3, Canada
| | - Ben F Koop
- Centre for Biomedical Research, Department of Biology, University of Victoria, 3800 Finnerty Rd, Victoria, BC, V8W 3N5, Canada
| | - Simon R M Jones
- Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, BC, V9T 6N7, Canada.
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Eichner C, Øvergård AC, Nilsen F, Dalvin S. Molecular characterization and knock-down of salmon louse (Lepeophtheirus salmonis) prostaglandin E synthase. Exp Parasitol 2015; 159:79-93. [DOI: 10.1016/j.exppara.2015.09.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 06/23/2015] [Accepted: 09/03/2015] [Indexed: 11/29/2022]
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Liu Z. GIA 2013: Genomics in Aquaculture 2013 symposium. Mar Genomics 2014; 18 Pt A:1-2. [PMID: 25468061 DOI: 10.1016/j.margen.2014.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Molecular characterisation of the salmon louse, Lepeophtheirus salmonis salmonis (Krøyer, 1837), ecdysone receptor with emphasis on functional studies of female reproduction. Int J Parasitol 2014; 45:175-85. [PMID: 25444859 DOI: 10.1016/j.ijpara.2014.10.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 10/08/2014] [Accepted: 10/17/2014] [Indexed: 12/16/2022]
Abstract
The salmon louse Lepeophtheirus salmonis (Copepoda, Caligidae) is an important parasite in the salmon farming industry in the Northern Hemisphere causing annual losses of hundreds of millions of dollars (US) worldwide. To facilitate development of a vaccine or other novel measures to gain control of the parasite, knowledge about molecular biological functions of L. salmonis is vital. In arthropods, a nuclear receptor complex consisting of the ecdysone receptor and the retinoid X receptor, ultraspiracle, are well known to be involved in a variety of both developmental and reproductive processes. To investigate the role of the ecdysone receptor in the salmon louse, we isolated and characterised cDNA with the 5'untranslated region of the predicted L. salmonis EcR (LsEcR). The LsEcR cDNA was 1608 bp encoding a 536 amino acid sequence that demonstrated high sequence similarities to other arthropod ecdysone receptors including Tribolium castaneum and Locusta migratoria. Moreover, in situ analysis of adult female lice revealed that the LsEcR transcript is localised in a wide variety of tissues such as ovaries, sub-cuticula and oocytes. Knock-down studies of LsEcR using RNA interference terminated egg production, indicating that the LsEcR plays important roles in reproduction and oocyte maturation. We believe this is the first report on the ecdysone receptor in the economically important parasite L. salmonis.
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