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Casuso A, Benavente BP, Leal Y, Carrera-Naipil C, Valenzuela-Muñoz V, Gallardo-Escárate C. Sex-Biased Transcription Expression of Vitellogenins Reveals Fusion Gene and MicroRNA Regulation in the Sea Louse Caligus rogercresseyi. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2024; 26:243-260. [PMID: 38294574 DOI: 10.1007/s10126-024-10291-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 01/17/2024] [Indexed: 02/01/2024]
Abstract
The caligid ectoparasite, Caligus rogercresseyi, is one of the main concerns in the Chilean salmon industry. The molecular mechanisms displayed by the parasite during the reproductive process represent an opportunity for developing novel control strategies. Vitellogenin is a multifunctional protein recognized as a critical player in several crustaceans' biological processes, including reproduction, embryonic development, and immune response. This study aimed to characterize the C. rogercresseyi vitellogenins, including discovering novel transcripts and regulatory mechanisms associated with microRNAs. Herein, vitellogenin genes were identified by homology analysis using the reference sea louse genome, transcriptome database, and arthropods vitellogenin-protein database. The validation of expression transcripts was conducted by RNA nanopore sequencing technology. Moreover, fusion gene profiling, miRNA target analysis, and functional validation were performed using luciferase assay. Six putative vitellogenin genes were identified in the C. rogercresseyi genome with high homology with other copepods vitellogenins. Furthermore, miR-996 showed a putative role in regulating the Cr_Vitellogenin1 gene, which is highly expressed in females. Moreover, vitellogenin-fusion genes were identified in adult stages and highly regulated in males, demonstrating sex-related expression patterns. In females, the identified fusion genes merged with several non-vitellogenin genes involved in biological processes of ribosome assembly, BMP signaling pathway, and biosynthetic processes. This study reports the genome array of vitellogenins in C. rogercresseyi for the first time, revealing the putative role of fusion genes and miRNA regulation in sea lice biology.
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Affiliation(s)
- Antonio Casuso
- Interdisciplinary Center for Aquaculture Research (INCAR), Universidad de Concepción, Concepción, Chile
- Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, Universidad de Concepción, Concepción, Chile
| | - Bárbara P Benavente
- Interdisciplinary Center for Aquaculture Research (INCAR), Universidad de Concepción, Concepción, Chile
- Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, Universidad de Concepción, Concepción, Chile
| | - Yeny Leal
- Interdisciplinary Center for Aquaculture Research (INCAR), Universidad de Concepción, Concepción, Chile
- Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, Universidad de Concepción, Concepción, Chile
| | - Crisleri Carrera-Naipil
- Interdisciplinary Center for Aquaculture Research (INCAR), Universidad de Concepción, Concepción, Chile
| | - Valentina Valenzuela-Muñoz
- Interdisciplinary Center for Aquaculture Research (INCAR), Universidad de Concepción, Concepción, Chile
- Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, Universidad de Concepción, Concepción, Chile
| | - Cristian Gallardo-Escárate
- Interdisciplinary Center for Aquaculture Research (INCAR), Universidad de Concepción, Concepción, Chile.
- Laboratory of Biotechnology and Aquatic Genomics, Department of Oceanography, Universidad de Concepción, Concepción, Chile.
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Khan MT, Dalvin S, Nilsen F, Male R. Two apolipoproteins in salmon louse ( Lepeophtheirus salmonis), apolipoprotein 1 knock down reduces reproductive capacity. Biochem Biophys Rep 2021; 28:101156. [PMID: 34729423 PMCID: PMC8545670 DOI: 10.1016/j.bbrep.2021.101156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 10/07/2021] [Accepted: 10/17/2021] [Indexed: 11/19/2022] Open
Abstract
The salmon louse, Lepeophtheirus salmonis is an ectoparasite of salmonid fish in the Northern Hemisphere, causing large economical losses in the aquaculture industry and represent a threat to wild populations of salmonids. Like other oviparous animals, it is likely that female lice use lipoproteins for lipid transport to maturing oocytes and other organs of the body. As an important component of lipoproteins, apolipoproteins play a vital role in the transport of lipids through biosynthesis of lipoproteins. Apolipoproteins have been studied in detail in different organisms, but no studies have been done in salmon lice. Two apolipoprotein encoding genes (LsLp1 and LsLp2) were identified in the salmon lice genome. Transcriptional analysis revealed both genes to be expressed at all stages from larvae to adult with some variation, LsLp1 generally higher than LsLp2 and both at their highest levels in adult stages of the louse. In adult female louse, the LsLp1 and LsLp2 transcripts were found in the sub-epidermal tissue and the intestine. RNA interference-mediated knockdown of LsLp1 and LsLp2 in female lice resulted in reduced expression of both transcripts. LsLp1 knockdown female lice produced significantly less offspring than control lice, while knockdown of LsLp2 in female lice caused no reduction in the number of offspring. These results suggest that LsLp1 has an important role in reproduction in female salmon lice. Salmon lice are ectoparasites and a major threat to aquaculture industry and wild salmon. Two apolipoproteins in salmon louse (Lepeophtheirus salmonis). Expressed at all stages from larvae to adult, sub-epidermal tissue and the intestine . RNA interference-mediated knockdown of LsLp1 and LsLp2. LsLp1 knockdown female lice produced significantly less offspring than control lice.
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Key Words
- Apolipoproteins
- CP, clotting protein
- Crustacea
- DIG, Digoxigenin
- Ectoparasite
- Gene expression
- LDL, low density lipoprotein
- LLTP, large lipid transfer protein
- Lp, lipophorin
- Ls, Lepeophtheirus salmonis
- MTP, microsomal triglyceride transfer protein
- RNAi
- RNAi, RNA interference
- Reproduction
- Vit, vitellogenins
- apo B-100, apolipoprotein B-100
- apoCr, apolipocrustaceins
- apoLp-II/I, apolipophorin-II/I
- dLPs, large discoidal lipoproteins
- ef1α, elongation factor 1 alpha
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Affiliation(s)
- Muhammad Tanveer Khan
- 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
| | - Frank Nilsen
- Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Rune Male
- Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Bergen, Norway
- Corresponding author. Department of Biological Sciences, University of Bergen, P.O. Box 7803, N-5020, Bergen, Norway.
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Thompson CRS, Bron JE, Bui S, Dalvin S, Fordyce MJ, Furmanek T, Á Norði G, Skern-Mauritzen R. Illuminating the planktonic stages of salmon lice: A unique fluorescence signal for rapid identification of a rare copepod in zooplankton assemblages. JOURNAL OF FISH DISEASES 2021; 44:863-879. [PMID: 33586246 DOI: 10.1111/jfd.13345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/12/2021] [Accepted: 01/13/2021] [Indexed: 06/12/2023]
Abstract
Monitoring of planktonic salmon louse (Lepeophtheirus salmonis salmonis) abundance and parameterization of key life-history traits has been hindered by labour-intensive and error-prone quantification using traditional light microscopy. Fluorescence illumination has been proposed as a means of improving visualization, but prior to this study adequate investigation of the relevant fluorescence profiles and measurement conditions has not been undertaken. We investigated the fluorescence profiles of L. salmonis and non-target copepod spp. with excitation and emission matrices (200-600 nm) and identified unique fluorescence signals. Fluorescence microscopy using excitation wavelengths of 470 ± 40 nm, and emission wavelengths of 525 ± 50 nm, showed that after 90 days of formalin storage salmon lice have a mean fluorescence intensity that is 2.4 times greater than non-target copepods (copepodid and adult stages). A 7-day heat treatment of 42°C in formalin increased the difference between salmon louse copepodids and non-target copepods to a factor of 3.6, eliminating the need for prolonged storage. Differences in the fluorescence signal and endogenous fluorophores were investigated with respect to variation in sea lice species, age, stage and host fish origin. Under the conditions outlined in this paper, the fluorescence signal was found to be a reliable means of visualizing and differentiating salmon lice from non-target zooplankters. Adaptation of the fluorescence signal would greatly expedite traditional methods of enumerating salmon louse larvae in plankton samples and could provide a means of automated detection.
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Affiliation(s)
| | | | | | | | | | | | - Gunnvør Á Norði
- Fiskaaling - Aquaculture Research Station of the Faroes, Hvalvík, Faroe Islands
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The FTZ-F1 gene encodes two functionally distinct nuclear receptor isoforms in the ectoparasitic copepod salmon louse (Lepeophtheirus salmonis). PLoS One 2021; 16:e0251575. [PMID: 34014986 PMCID: PMC8136749 DOI: 10.1371/journal.pone.0251575] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 04/29/2021] [Indexed: 01/21/2023] Open
Abstract
The salmon louse, Lepeophtheirus salmonis, is an ectoparasitic crustacean that annually inflicts substantial losses to the aquaculture industry in the northern hemisphere and poses a threat to the wild populations of salmonids. The salmon louse life cycle consists of eight developmental stages each separated by a molt. Fushi Tarazu Factor-1 (FTZ-F1) is an ecdysteroid-regulated gene that encodes a member of the NR5A family of nuclear receptors that is shown to play a crucial regulatory role in molting in insects and nematodes. Characterization of an FTZ-F1 orthologue in the salmon louse gave two isoforms named αFTZ-F1 and βFTZ-F1, which are identical except for the presence of a unique N-terminal domain (A/B domain). A comparison suggest conservation of the FTZ-F1 gene structure among ecdysozoans, with the exception of nematodes, to produce isoforms with unique N-terminal domains through alternative transcription start and splicing. The two isoforms of the salmon louse FTZ-F1 were expressed in different amounts in the same tissues and showed a distinct cyclical expression pattern through the molting cycle with βFTZ-F1 being the highest expressed isoform. While RNA interference knockdown of βFTZ-F1 in nauplius larvae and in pre-adult males lead to molting arrest, knockdown of βFTZ-F1 in pre-adult II female lice caused disruption of oocyte maturation at the vitellogenic stage. No apparent phenotype could be observed in αFTZ-F1 knockdown larvae, or in their development to adults, and no genes were found to be differentially expressed in the nauplii larvae following αFTZ-F1 knockdown. βFTZ-F1 knockdown in nauplii larvae caused both down and upregulation of genes associated with proteolysis and chitin binding and affected a large number of genes which are in normal salmon louse development expressed in a cyclical pattern. This is the first description of FTZ-F1 gene function in copepod crustaceans and provides a foundation to expand the understanding of the molecular mechanisms of molting in the salmon louse and other copepods.
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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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Abundances of vitellogenin and heat shock protein 90 during ovarian and embryonic development of Exopalaemon carinicauda. Anim Reprod Sci 2020; 223:106633. [PMID: 33099104 DOI: 10.1016/j.anireprosci.2020.106633] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 10/13/2020] [Accepted: 10/14/2020] [Indexed: 11/23/2022]
Abstract
To evaluate functions of vitellogenin (Vg) and heat shock protein 90 (Hsp90) during ovarian and embryonic development of Exopalaemon carinicauda, the cDNA of Vg (Ec-Vg) was cloned, and the abundances of Ec-Vg and heat shock protein 90 (Hsp90) (Ec-Hsp90) were determined during ovarian and embryonic development. During ovarian development, the concentration of Vg protein in hemolymph was markedly greater than in the ovary and hepatopancreas, and was greatest at sexual maturity. The relative abundance of Ec-Vg mRNA transcript was greatest in the hepatopancreas and almost undetectable in hemocytes. By combining mRNA transcript relative abundances with morphological results, a model was developed to explain the mRNA transcript relative abundance of Ec-Hsp90 and Ec-Vg during ovarian and embryonic development. The relative abundance of Ec-Vg mRNA transcript was greatest during the recovery period after reproduction had occurred (Stage V) and mature stage (Stage IV) in the ovary or hepatopancreas, respectively. There were marked associations of the patterns of Ec-Hsp90 and Ec-Vg mRNA transcript abundances both in hepatopancreas and ovary. During embryonic development, the relative abundance of the two mRNA transcripts were greatest at the metazoea and protozoea stages, respectively. These results indicate that Ec-Vg is produced primarily in the hepatopancreas, secreted into the hemolymph and transported into growing oocytes. It, therefore, is believed that Ec-Vg has an important function in the overall ovarian development and late embryonic development of E. carinicauda. In contrast, Ec-Hsp90 is a regulatory factor for Vg transcription and is important during early organogenesis in E. carinicauda.
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AmbuAli A, Monaghan SJ, McLean K, Inglis NF, Bekaert M, Wehner S, Bron JE. Identification of proteins from the secretory/excretory products (SEPs) of the branchiuran ectoparasite Argulus foliaceus (Linnaeus, 1758) reveals unique secreted proteins amongst haematophagous ecdysozoa. Parasit Vectors 2020; 13:88. [PMID: 32070416 PMCID: PMC7029603 DOI: 10.1186/s13071-020-3964-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 02/13/2020] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND It is hypothesised that being a blood-feeding ectoparasite, Argulus foliaceus (Linnaeus, 1758), uses similar mechanisms for digestion and host immune evasion to those used by other haematophagous ecdysozoa, including caligid copepods (e.g. sea louse). We recently described and characterised glands associated with the feeding appendages of A. foliaceus using histological techniques. The work described in the present study is the first undertaken with the objective of identifying and partially characterising the components secreted from these glands using a proteomic approach. METHODS Argulus foliaceus parasites were sampled from the skin of rainbow trout (Oncorhynchus mykiss), from Loch Fad on the Isle of Bute, Scotland, UK. The proteins from A. foliaceus secretory/excretory products (SEPs) were collected from the supernatant of artificial freshwater conditioned with active adult parasites (n = 5-9 per ml; n = 560 total). Proteins within the SEPs were identified and characterised using LC-ESI-MS/MS analysis. Data are available via ProteomeXchange with identifier PXD016226. RESULTS Data mining of a protein database translated from an A. foliaceus dataset using ProteinScape allowed identification of 27 predicted protein sequences from the A. foliaceus SEPs, each protein matching the criteria of 2 peptides with at least 4 contiguous amino acids. Nine proteins had no matching sequence through OmicsBox (Blast2GO) analysis searches suggesting that Argulus spp. may additionally have unique proteins present in their SEPs. SignalP 5.0 software, identified 13 proteins with a signal sequence suggestive of signal peptides and supportive of secreted proteins being identified. Notably, the functional characteristics of identified A. foliaceus proteins/domains have also been described from the salivary glands and saliva of other blood-feeding arthropods such as ticks. Identified proteins included: transporters, peroxidases, metalloproteases, proteases and serine protease inhibitors which are known to play roles in parasite immune evasion/induction (e.g. astacin), immunomodulation (e.g. serpin) and digestion (e.g. trypsin). CONCLUSIONS To our knowledge, the present study represents the first proteomic analysis undertaken for SEPs from any branchiuran fish louse. Here we reveal possible functional roles of A. foliaceus SEPs in digestion and immunomodulation, with a number of protein families shared with other haematophagous ectoparasites. A number of apparently unique secreted proteins were identified compared to other haematophagous ecdysozoa.
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Affiliation(s)
- Aisha AmbuAli
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA UK
- Department of Marine Science and Fisheries, College of Agricultural and Marine Sciences, Sultan Qaboos University, PO Box 34, 123 Al-Khoud, Sultanate of Oman
| | - Sean J. Monaghan
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA UK
| | - Kevin McLean
- Moredun Proteomics Facility, Moredun Research Institute, Pentland Science Park, Bush Loan, Penicuik, Midlothian, EH26 0PZ UK
| | - Neil F. Inglis
- Moredun Proteomics Facility, Moredun Research Institute, Pentland Science Park, Bush Loan, Penicuik, Midlothian, EH26 0PZ UK
| | - Michaël Bekaert
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA UK
| | - Stefanie Wehner
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA UK
- Max Planck Institute of Psychiatry, Kraepelinstr. 2-10, 80804 Munich, Germany
| | - James E. Bron
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA UK
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Identification and Description of the Key Molecular Components of the Egg Strings of the Salmon Louse ( Lepeophtheirus salmonis). Genes (Basel) 2019; 10:genes10121004. [PMID: 31817028 PMCID: PMC6947537 DOI: 10.3390/genes10121004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 11/21/2019] [Accepted: 11/30/2019] [Indexed: 12/12/2022] Open
Abstract
The salmon louse Lepeophtheirus salmonis is a parasite of Atlantic salmon and other salmonids. Every year, it causes high costs for the Norwegian aquaculture industry. While the morphology of the female genital tract has been described, knowledge of the molecular basis of reproduction is very limited. We identified nine genes which are expressed exclusively in the female cement gland, the organ responsible for cement production, which is used to hold the eggs together and keep them attached to their mother in egg strings. Six of these genes encode proteins with signal peptides and probably form the main component of the cement. Two other genes are peroxidases, which are probably important in the cement formation. The last gene is not similar to any known protein, but contains a transmembrane domain. A knockdown of all these genes leads to missing or deformed egg strings, preventing reproduction of the lice. The correct assemblage of the cement in the cement gland is essential for successful reproduction of salmon lice. Similar proteins seem to be present in other copepod species, as well.
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Tarrant AM, Nilsson B, Hansen BW. Molecular physiology of copepods - from biomarkers to transcriptomes and back again. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2019; 30:230-247. [DOI: 10.1016/j.cbd.2019.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 03/14/2019] [Accepted: 03/16/2019] [Indexed: 12/31/2022]
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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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Núñez-Acuña G, Gallardo-Escárate C. Characterization of the salmon louse Lepeophtheirus salmonis miRNome: Sex-biased differences related to the coding and non-coding RNA interplay. Mar Genomics 2019; 45:38-47. [PMID: 30772247 DOI: 10.1016/j.margen.2019.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 01/21/2019] [Accepted: 01/21/2019] [Indexed: 12/12/2022]
Abstract
The salmon louse Lepeophtheirus salmonis is a marine ectoparasite that has a detrimental impact on salmon farms. Genomic knowledge of adult stages is critical to understand the reproductive success and lifecycle completion of this species. Here, we report a comprehensive characterization of the L. salmonis miRNome with emphasis on the sex-differences of the parasite. Small-RNA sequencing was conducted on males and females, and mRNA-sequencing was also conducted to identify miRNA-targets at these stages. Based on bioinformatics analyses, 3101 putative miRNAs were found in L. salmonis, including precursors and variants. The most abundant and over-expressed miRNAs belonged to the bantam, mir-100, mir-1, mir-263a and mir-276 families, while the most differentially expressed mRNAs corresponded to genes related to reproduction and other biological processes involved in cell-differentiation. Target analyses revealed that the most up-regulated miRNAs in males can act by inhibiting the expression of genes related to female differentiation such as vitellogenin genes. Target prediction and expression patterns suggested a pivotal role of miRNAs in the reproductive development of L. salmonis.
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Affiliation(s)
- Gustavo Núñez-Acuña
- Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, Concepción, Chile
| | - Cristian Gallardo-Escárate
- Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, Concepción, Chile.
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Khan MT, Dalvin S, Waheed Q, Nilsen F, Male R. Molecular characterization of the lipophorin receptor in the crustacean ectoparasite Lepeophtheirus salmonis. PLoS One 2018; 13:e0195783. [PMID: 29649335 PMCID: PMC5897026 DOI: 10.1371/journal.pone.0195783] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 03/29/2018] [Indexed: 12/11/2022] Open
Abstract
The Salmon louse (Lepeophtheirus salmonis) is a marine ectoparasite of salmonid fish in the Northern Hemisphere and considered as a major challenge in aquaculture and a threat to wild populations of salmonids. Adult female lice produce a large number of lipid-rich eggs, however, the mechanism of maternal lipid transport into developing eggs during salmon louse reproduction has not been described. In the present study, a full-length L. salmonis lipophorin receptor (LsLpR) consisting of 16 exons was obtained by RACE and RT-PCR. The predicted ORF was 952 amino acids and structural analysis showed five functional domains that are similar to LpR of insects and decapods. Phylogenetic analysis placed the LsLpR together with LpRs from decapods and insects. Expression analysis revealed that the relative abundance of LsLpR transcripts was highest in the larvae and adult female lice. In adult females, the LsLpR transcripts and protein were found in the ovary and vitellogenic oocytes whereas, in larvae, the LsLpR transcripts were found in the neuronal somata of the brain and the intestine. Oil Red O stain results revealed that storage of neutral lipids was found in vitellogenic oocytes and ovaries of adult females, and in the yolk of larvae. Moreover, RNA interference (RNAi) was conducted to demonstrate the function of LsLpR in reproduction and lipid metabolism in L. salmonis. In larvae, the transcription of LsLpR was decreased by 44–54% while in an experiment LsLpR knockdown female lice produced 72% less offspring than control lice.
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Affiliation(s)
- Muhammad Tanveer Khan
- 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
| | - Qaiser Waheed
- Computational Biology Unit, Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Frank Nilsen
- Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Rune Male
- Computational Biology Unit, Department of Biological Sciences, University of Bergen, Bergen, Norway
- * E-mail:
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Sandlund L, Kongshaug H, Nilsen F, Dalvin S. Molecular characterization and functional analysis of components of the TOR pathway of the salmon louse, Lepeophtheirus salmonis (Krøyer, 1838). Exp Parasitol 2018; 188:83-92. [PMID: 29625096 DOI: 10.1016/j.exppara.2018.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/16/2018] [Accepted: 04/02/2018] [Indexed: 11/27/2022]
Abstract
The salmon louse Lepeophtheirus salmonis (Copepods, Caligida) is a marine ectoparasite infecting salmonid fishes in the northern hemisphere. At present, salmon lice infections are the most severe disease problem in the salmon farming industry causing significant economic losses. Due to development of resistance towards available chemotherapeutants, it is clear that new chemotherapeutants or non-chemical control methods are essential to manage the parasite in the future. The TOR signaling pathway is present in all metazoans and is a major regulator of cellular activity according to nutrient availability. In this study, we identified the TOR pathway genes in salmon louse; LsTSC1, LsTSC2, LsRheb, LsTOR, LsRaptor and LsRictor. RNA interference mediated gene silencing was performed to elucidate the functional role of each member of the pathway. Our results show that interference of the TOR signaling pathway either directly or indirectly inhibits many biological processes including egg maturation. In addition, the effect of gene knock-down results in more comprehensive physiological defects when targeting TORC1 and the upstream regulator Rheb. This is the first report on the TOR pathway in the salmon louse and that our research contributes to the basic knowledge of the parasite that could lead to development of novel treatment methods.
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Affiliation(s)
- Liv Sandlund
- SLRC-Sea Lice Research Center, Institute of Marine Research, 5817 Bergen, Norway
| | - Heidi Kongshaug
- SLRC-Sea Lice Research Center, Department of Biology, University of Bergen, Thormøhlensgt. 55, 5008 Bergen, Norway
| | - Frank Nilsen
- SLRC-Sea Lice Research Center, Department of Biology, University of Bergen, Thormøhlensgt. 55, 5008 Bergen, Norway
| | - Sussie Dalvin
- SLRC-Sea Lice Research Center, Institute of Marine Research, 5817 Bergen, Norway.
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14
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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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15
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Borchel A, Komisarczuk AZ, Rebl A, Goldammer T, Nilsen F. Systematic identification and characterization of stress-inducible heat shock proteins (HSPs) in the salmon louse (Lepeophtheirus salmonis). Cell Stress Chaperones 2018; 23:127-139. [PMID: 28695332 PMCID: PMC5741587 DOI: 10.1007/s12192-017-0830-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 06/21/2017] [Accepted: 06/23/2017] [Indexed: 02/06/2023] Open
Abstract
Salmon lice (Lepeophtheirus salmonis) are parasitic copepods, living mainly on Atlantic salmon and leading to large economical losses in aquaculture every year. Due to the emergence of resistances to several drugs, alternative treatments are developed, including treatment with hydrogen peroxide, freshwater or thermal treatment. The present study gives a first overview of the thermotolerance and stress response of salmon lice. Sea lice nauplii acclimated to 10 °C can survive heat shocks up to 30 °C and are capable of hardening by a sublethal heat shock. We searched in the genome for heat shock protein (HSP) encoding genes and tested their inducibility after heat shock, changes in salinity and treatment with hydrogen peroxide, employing microfluidic qPCRs. We assessed 38 candidate genes, belonging to the small HSP, HSP40, HSP70 and HSP90 families. Nine of these genes showed strong induction after a non-lethal heat shock. In contrast, only three and two of these genes were induced after changes in salinity and incubation in hydrogen peroxide, respectively. This work provides the basis for further work on the stress response on the economically important parasite L. salmonis.
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Affiliation(s)
- Andreas Borchel
- SLRC-Sea Lice Research Centre, Department of Biology, University of Bergen, Thormøhlensgt. 55, 5008, Bergen, Norway.
| | - Anna Z Komisarczuk
- SLRC-Sea Lice Research Centre, Department of Biology, University of Bergen, Thormøhlensgt. 55, 5008, Bergen, Norway
| | - Alexander Rebl
- Leibniz Institute for Farm Animal Biology (FBN), Institute of Genome Biology, Wilhelm-Stahl-Allee 2, 18196, Dummerstorf, Germany
| | - Tom Goldammer
- Leibniz Institute for Farm Animal Biology (FBN), Institute of Genome Biology, Wilhelm-Stahl-Allee 2, 18196, Dummerstorf, Germany
| | - Frank Nilsen
- SLRC-Sea Lice Research Centre, Department of Biology, University of Bergen, Thormøhlensgt. 55, 5008, Bergen, Norway
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16
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Øvergård AC, Hamre LA, Kongshaug H, Nilsen F. RNAi-mediated treatment of two vertically transmitted rhabdovirus infecting the salmon louse (Lepeophtheirus salmonis). Sci Rep 2017; 7:14030. [PMID: 29070796 PMCID: PMC5656668 DOI: 10.1038/s41598-017-14282-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/06/2017] [Indexed: 12/21/2022] Open
Abstract
Rhabdoviruses are a family of enveloped negative-sense single-stranded RNA viruses infecting a variety of hosts. Recently, two vertically transmitted salmon louse (Lepeophtheirus salmonis) rhabdoviruses (LsRV) have been identified. The prevalence of these viruses was measured along the Norwegian coast and found to be close to 100%, and with the present lack of suitable cell lines to propagate these viruses, it is challenging to obtain material to study their host impact and infection routes. Thus, virus free lice strains were established from virus infected lice carrying one or both LsRVs by treating them with N protein dsRNA twice during development. The viral replication of the N protein was specifically down-regulated following introduction of virus-specific dsRNA, and virus-free lice strains were maintained for several generations. A preliminary study on infection routes suggested that the LsRV-No9 is maternally transmitted, and that the virus transmits from males to females horizontally. The ability to produce virus free strains allows for further studies on transmission modes and how these viruses influences on the L.salmonis interaction with its salmonid host. Moreover, this study provides a general fundament for future studies on how vertically transmitted rhabdoviruses influence the biology of their arthropod hosts.
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Affiliation(s)
- Aina-Cathrine Øvergård
- SLCR-Sea Lice Research Centre, Department of Biology, University of Bergen, Thormøhlensgt. 55, Pb. 7803, NO-5020, Bergen, Norway.
| | - Lars Are Hamre
- SLCR-Sea Lice Research Centre, Department of Biology, University of Bergen, Thormøhlensgt. 55, Pb. 7803, NO-5020, Bergen, Norway
| | - Heidi Kongshaug
- SLCR-Sea Lice Research Centre, Department of Biology, University of Bergen, Thormøhlensgt. 55, Pb. 7803, NO-5020, Bergen, Norway
| | - Frank Nilsen
- SLCR-Sea Lice Research Centre, Department of Biology, University of Bergen, Thormøhlensgt. 55, Pb. 7803, NO-5020, Bergen, Norway
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Boulangé-Lecomte C, Xuereb B, Trémolet G, Duflot A, Giusti N, Olivier S, Legrand E, Forget-Leray J. Controversial use of vitellogenin as a biomarker of endocrine disruption in crustaceans: New adverse pieces of evidence in the copepod Eurytemora affinis. Comp Biochem Physiol C Toxicol Pharmacol 2017; 201:66-75. [PMID: 28974407 DOI: 10.1016/j.cbpc.2017.09.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 09/20/2017] [Accepted: 09/28/2017] [Indexed: 12/16/2022]
Abstract
In recent years, the interest in the use of vitellogenin (VTG) as a biomarker of endocrine disruption in fish has led to VTG being considered as a potential tool in invertebrates. Among aquatic invertebrate models in ecotoxicology, the copepods are considered as reference species in marine, estuarine and freshwater ecosystems. In this context, we identified a VTG cDNA in Eurytemora affinis. The Ea-VTG2 cDNA is 5416bp in length with an open reading frame (ORF) of 5310bp that encodes a putative protein of 1769 amino acids residues. Phylogenetic analysis confirmed the hypothesis of a VTG duplication event before the emergence of the copepod species. The analysis of the Ea-VTG2 expression by qPCR in males and females according to their reproductive stages allowed transcript basal levels to be determined. The expression pattern revealed a gradual increase of transcript levels during maturation in females. Important inter-sex differences were observed with a VTG level in males ranging from about 1900- to 6800-fold lower than in females depending on their stage. Moreover, the protein was only detected in ovigerous females. The inducibility of Ea-VTG2 by chemicals was studied in males exposed to either a model of endocrine disruptor in vertebrates i.e. 4-nonylphenol (4-NP) or a crustacean hormone i.e. Methyl Farnesoate (MF), and in males sampled from a multi-contaminated estuary. No induction was highlighted. The VTG should not be considered as an appropriate biomarker in E. affinis as previously suggested for other crustaceans.
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Affiliation(s)
| | - Benoit Xuereb
- Normandie Univ, ULHN, UMR-I 02 SEBIO, FR CNRS 3730 SCALE BP 1123, F-76063 Le Havre, France
| | - Gauthier Trémolet
- Normandie Univ, ULHN, UMR-I 02 SEBIO, FR CNRS 3730 SCALE BP 1123, F-76063 Le Havre, France
| | - Aurélie Duflot
- Normandie Univ, ULHN, UMR-I 02 SEBIO, FR CNRS 3730 SCALE BP 1123, F-76063 Le Havre, France
| | - Nathalie Giusti
- Normandie Univ, ULHN, UMR-I 02 SEBIO, FR CNRS 3730 SCALE BP 1123, F-76063 Le Havre, France
| | - Stéphanie Olivier
- Normandie Univ, ULHN, UMR-I 02 SEBIO, FR CNRS 3730 SCALE BP 1123, F-76063 Le Havre, France
| | - Elena Legrand
- Normandie Univ, ULHN, UMR-I 02 SEBIO, FR CNRS 3730 SCALE BP 1123, F-76063 Le Havre, France
| | - Joëlle Forget-Leray
- Normandie Univ, ULHN, UMR-I 02 SEBIO, FR CNRS 3730 SCALE BP 1123, F-76063 Le Havre, France
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Khan MT, Dalvin S, Nilsen F, Male R. Microsomal triglyceride transfer protein in the ectoparasitic crustacean salmon louse ( Lepeophtheirus salmonis). J Lipid Res 2017; 58:1613-1623. [PMID: 28601811 PMCID: PMC5538283 DOI: 10.1194/jlr.m076430] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 05/10/2017] [Indexed: 11/20/2022] Open
Abstract
The salmon louse, Lepeophtheirus salmonis, is an endemic ectoparasite on salmonid fish that is challenging for the salmon farming industry and wild fish. Salmon lice produce high numbers of offspring, necessitating sequestration of large amounts of lipids into growing oocytes as a major energy source for larvae, most probably mediated by lipoproteins. The microsomal triglyceride transfer protein (MTP) is essential for the assembly of lipoproteins. Salmon lice have three L. salmonis MTP (LsMTP) transcript variants encoding two different protein isoforms, which are predicted to contain three β-sheets (N, C, and A) and a central helical domain, similar to MTPs from other species. In adult females, the LsMTPs are differently transcribed in the sub-cuticular tissues, the intestine, the ovary, and in the mature eggs. RNA interference-mediated knockdown of LsMTP in mature females gave offspring with significantly fewer neutral lipids in their yolk and only 10-30% survival. The present study suggests the importance of LsMTP in reproduction and lipid metabolism in adult female L. salmonis, a possible metabolic bottleneck that could be exploited for the development of new anti-parasitic treatment methods.
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Affiliation(s)
| | - Sussie Dalvin
- Sea Lice Research Centre, Institute of Marine Research, 5817 Bergen, Norway
| | - Frank Nilsen
- Departments of Biology University of Bergen, N-5020 Bergen, Norway
| | - Rune Male
- Molecular Biology, Sea Lice Research Centre, University of Bergen, N-5020 Bergen, Norway.
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19
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The Caligus rogercresseyi miRNome: Discovery and transcriptome profiling during the sea lice ontogeny. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.aggene.2017.03.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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20
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Legrand E, Forget-Leray J, Duflot A, Olivier S, Thomé JP, Danger JM, Boulangé-Lecomte C. Transcriptome analysis of the copepod Eurytemora affinis upon exposure to endocrine disruptor pesticides: Focus on reproduction and development. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 176:64-75. [PMID: 27111276 DOI: 10.1016/j.aquatox.2016.04.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Revised: 03/19/2016] [Accepted: 04/12/2016] [Indexed: 06/05/2023]
Abstract
Copepods-which include freshwater and marine species-represent the most abundant group of aquatic invertebrates. Among them, the calanoid copepod Eurytemora affinis is widely represented in the northern hemisphere estuaries and has become a species of interest in ecotoxicology. Like other non-target organisms, E. affinis may be exposed to a wide range of chemicals such as endocrine disruptors (EDs). This study investigated the gene expression variation in E. affinis after exposure to ED pesticides-chosen as model EDs-in order to (i) improve the knowledge on their effects in crustaceans, and (ii) highlight relevant transcripts for further development of potential biomarkers of ED exposure/effect. The study focused on the reproduction function in response to ED. Copepods were exposed to sublethal concentrations of pyriproxyfen (PXF) and chlordecone (CLD) separately. After 48h, males and females (400 individuals each) were sorted for RNA extraction. Their transcriptome was pyrosequenced using the Illumina(®) technology. Contigs were blasted and functionally annotated using Blast2GO(®). The differential expression analysis between ED- and acetone-exposed organisms was performed according to sexes and contaminants. Half of the 19,721 contigs provided by pyrosequencing were annotated, mostly (80%) from arthropod sequences. Overall, 2,566 different genes were differentially expressed after ED exposures in comparison with controls. As many genes were differentially expressed after PXF exposure as after CLD exposure. In contrast, more genes were differentially expressed in males than in females after both exposures. Ninety-seven genes overlapped in all conditions. Finally, 31 transcripts involved in reproduction, growth and development, and changed in both chemical exposures were selected as potential candidates for future development of biomarkers.
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Affiliation(s)
- Eléna Legrand
- Normandy University, ULH, UMR-I 02 INERIS, Environmental Stresses and Biomonitoring of Aquatic Ecosystems (SEBIO)-SFR SCALE 4116, F-76600 Le Havre, France.
| | - Joëlle Forget-Leray
- Normandy University, ULH, UMR-I 02 INERIS, Environmental Stresses and Biomonitoring of Aquatic Ecosystems (SEBIO)-SFR SCALE 4116, F-76600 Le Havre, France.
| | - Aurélie Duflot
- Normandy University, ULH, UMR-I 02 INERIS, Environmental Stresses and Biomonitoring of Aquatic Ecosystems (SEBIO)-SFR SCALE 4116, F-76600 Le Havre, France.
| | - Stéphanie Olivier
- Normandy University, ULH, UMR-I 02 INERIS, Environmental Stresses and Biomonitoring of Aquatic Ecosystems (SEBIO)-SFR SCALE 4116, F-76600 Le Havre, France.
| | - Jean-Pierre Thomé
- University of Liège, Laboratory of Animal Ecology and Ecotoxicology (LEAE), Centre for Analytical Research and Technology (CART), 4000 SART-Tilman, Belgium.
| | - Jean-Michel Danger
- Normandy University, ULH, UMR-I 02 INERIS, Environmental Stresses and Biomonitoring of Aquatic Ecosystems (SEBIO)-SFR SCALE 4116, F-76600 Le Havre, France.
| | - Céline Boulangé-Lecomte
- Normandy University, ULH, UMR-I 02 INERIS, Environmental Stresses and Biomonitoring of Aquatic Ecosystems (SEBIO)-SFR SCALE 4116, F-76600 Le Havre, France.
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Alqaisi KM, Lamare MD, Grattan DR, Damsteegt EL, Schneider WJ, Lokman PM. A comparative study of vitellogenesis in Echinodermata: Lessons from the sea star. Comp Biochem Physiol A Mol Integr Physiol 2016; 198:72-86. [PMID: 27085373 DOI: 10.1016/j.cbpa.2016.04.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 04/02/2016] [Accepted: 04/09/2016] [Indexed: 11/19/2022]
Abstract
The provision of yolk precursor proteins to the oviparous egg is crucial for normal embryo development. In Echinodermata, a transferrin-like yolk component termed major yolk protein (MYP) is a major precursor protein in Echinoidea and Holothuroidea. In contrast, in Asteroidea a single vitellogenin (Vtg) was recently identified, but its role as primary yolk protein remains unclear. To resolve the apparent MYP-Vtg dichotomy in sea stars and to understand the dynamics of candidate yolk protein gene expression during the reproductive cycle, we investigated the molecular structures of sea star Vtg and MYP and quantified their transcript levels during oogenesis. By combining protein sequencing of the predominant proteins in ovulated eggs of Patiriella regularis with ovarian transcriptome sequencing and molecular cloning, we characterized two cDNAs encoding two bona fide Vtgs (PrVtg1 and PrVtg2) and a partial cDNA encoding MYP (PrMYP). PrMYP mRNA was found in low abundance in growing oocytes, possibly as maternal transcripts for translation after ovulation. In contrast, PrVtg transcripts, whose levels varied during the reproductive cycle, were not found in developing oocytes - rather, they were detected in ovarian follicle cells and pyloric caeca, indicating an extra-oocytic origin. Vtg accumulating in oocytes was stored in the form of cleaved products, which constituted the most abundant yolk polypeptides in ovulated sea star eggs; their levels decreased during early embryonic and larval development. Together, these traits are the hallmarks of a classical yolk protein - and hence, we contend that Vtg, and not MYP, is the main yolk protein in asteroids.
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Affiliation(s)
- Khalid M Alqaisi
- Department of Zoology, University of Otago, 340 Great King Street, Dunedin 9016, New Zealand.
| | - Miles D Lamare
- Department of Marine Science, University of Otago, 310 Castle Street, Dunedin 9016, New Zealand
| | - Dave R Grattan
- Department of Anatomy, University of Otago, 270 Great King Street, Dunedin 9016, New Zealand
| | - Erin L Damsteegt
- Department of Zoology, University of Otago, 340 Great King Street, Dunedin 9016, New Zealand
| | - Wolfgang J Schneider
- Department of Medical Biochemistry, Medical University of Vienna, Max F. Perutz Laboratories, Dr. Bohr Gasse 9, 1030 Vienna, Austria
| | - P Mark Lokman
- Department of Zoology, University of Otago, 340 Great King Street, Dunedin 9016, New Zealand
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Lee SR, Lee JH, Kim AR, Kim S, Park H, Baek HJ, Kim HW. Three cDNAs encoding vitellogenin homologs from Antarctic copepod, Tigriopus kingsejongensis: Cloning and transcriptional analysis in different maturation stages, temperatures, and putative reproductive hormones. Comp Biochem Physiol B Biochem Mol Biol 2016; 192:38-48. [DOI: 10.1016/j.cbpb.2015.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 11/11/2015] [Accepted: 11/20/2015] [Indexed: 10/22/2022]
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Tröße C, Kongshaug H, Dondrup M, Nilsen F. Characterisation of iron regulatory protein 1A and 1B in the blood-feeding copepod Lepeophtheirus salmonis. Exp Parasitol 2015; 157:1-11. [DOI: 10.1016/j.exppara.2015.06.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 04/21/2015] [Accepted: 06/15/2015] [Indexed: 11/29/2022]
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Zhang S, Dong Y, Cui P. Vitellogenin is an immunocompetent molecule for mother and offspring in fish. FISH & SHELLFISH IMMUNOLOGY 2015; 46:710-715. [PMID: 26282682 DOI: 10.1016/j.fsi.2015.08.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 08/08/2015] [Accepted: 08/12/2015] [Indexed: 06/04/2023]
Abstract
Our understanding of the function of vitellogenin (Vg) in reproduction has undergone a transformation over the past decade in parallel with new insights into the role of Vg in immunity. Initially, Vg was regarded as a female-specific reproductive protein, which is cleaved into yolk proteins such as phosvitin (Pv) and lipovitellin (Lv), stored in egg, providing the nutrients for developing embryos. Recently, Vg is shown to be an immune-relevant molecule involved in the defense of the host against the microbes including bacterium and virus. Furthermore, Pv and Lv, that both are proteolytically cleaved products of Vg, play a defense role in developing embryos. Importantly, yolk protein-derived small peptides also display antimicrobial activity. These data together indicate that Vg, in addition to being involved in yolk protein formation, plays a non-reproductive role via functioning as an immune-relevant molecule in both parent fishes and their offspring. It also shows that yolk proteins and their degraded peptides are novel players in maternal immunity, opening a new avenue to study the functions of reproductive proteins.
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Affiliation(s)
- Shicui Zhang
- Laboratory for Evolution & Development, Institute of Evolution & Marine Biodiversity and Department of Marine Biology, Ocean University of China, Qingdao 266003, China.
| | - Yuan Dong
- Laboratory for Evolution & Development, Institute of Evolution & Marine Biodiversity and Department of Marine Biology, Ocean University of China, Qingdao 266003, China
| | - Pengfei Cui
- Laboratory for Evolution & Development, Institute of Evolution & Marine Biodiversity and Department of Marine Biology, Ocean University of China, Qingdao 266003, China
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25
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Eichner C, Dalvin S, Skern-Mauritzen R, Malde K, Kongshaug H, Nilsen F. Characterization of a novel RXR receptor in the salmon louse (Lepeophtheirus salmonis, Copepoda) regulating growth and female reproduction. BMC Genomics 2015; 16:81. [PMID: 25765704 PMCID: PMC4333900 DOI: 10.1186/s12864-015-1277-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 01/22/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Nuclear receptors have crucial roles in all metazoan animals as regulators of gene transcription. A wide range of studies have elucidated molecular and biological significance of nuclear receptors but there are still a large number of animals where the knowledge is very limited. In the present study we have identified an RXR type of nuclear receptor in the salmon louse (Lepeophtheirus salmonis) (i.e. LsRXR). RXR is one of the two partners of the Ecdysteroid receptor in arthropods, the receptor for the main molting hormone 20-hydroxyecdysone (E20) with a wide array of effects in arthropods. RESULTS Five different LsRXR transcripts were identified by RACE showing large differences in domain structure. The largest isoforms contained complete DNA binding domain (DBD) and ligand binding domain (LBD), whereas some variants had incomplete or no DBD. LsRXR is transcribed in several tissues in the salmon louse including ovary, subcuticular tissue, intestine and glands. By using Q-PCR it is evident that the LsRXR mRNA levels vary throughout the L. salmonis life cycle. We also show that the truncated LsRXR transcript comprise about 50% in all examined samples. We used RNAi to knock-down the transcription in adult reproducing female lice. This resulted in close to zero viable offspring. We also assessed the LsRXR RNAi effects using a L. salmonis microarray and saw significant effects on transcription in the female lice. Transcription of the major yolk proteins was strongly reduced by knock-down of LsRXR. Genes involved in lipid metabolism and transport were also down regulated. Furthermore, different types of growth processes were up regulated and many cuticle proteins were present in this group. CONCLUSIONS The present study demonstrates the significance of LsRXR in adult female L. salmonis and discusses the functional aspects in relation to other arthropods. LsRXR has a unique structure that should be elucidated in the future.
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Affiliation(s)
- Christiane Eichner
- Department of Biology, Sea Lice Research Centre, University of Bergen, Bergen, Norway.
| | - Sussie Dalvin
- Department of Biology, Sea Lice Research Centre, University of Bergen, Bergen, Norway. .,Institute of Marine Research, Bergen, Norway.
| | | | - Ketil Malde
- Institute of Marine Research, Bergen, Norway.
| | - Heidi Kongshaug
- Department of Biology, Sea Lice Research Centre, University of Bergen, Bergen, Norway.
| | - Frank Nilsen
- Department of Biology, Sea Lice Research Centre, University of Bergen, Bergen, Norway.
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Tarrant AM, Baumgartner MF, Hansen BH, Altin D, Nordtug T, Olsen AJ. Transcriptional profiling of reproductive development, lipid storage and molting throughout the last juvenile stage of the marine copepod Calanus finmarchicus. Front Zool 2014; 11:91. [PMID: 25568661 PMCID: PMC4285635 DOI: 10.1186/s12983-014-0091-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 12/01/2014] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Calanus finmarchicus, a highly abundant copepod that is an important primary consumer in North Atlantic ecosystems, has a flexible life history in which copepods in the last juvenile developmental stage (fifth copepodid, C5) may either delay maturation and enter diapause or molt directly into adults. The factors that regulate this developmental plasticity are poorly understood, and few tools have been developed to assess the physiological condition of individual copepods. RESULTS We sampled a cultured population of C. finmarchicus copepods daily throughout the C5 stage and assessed molt stage progression, gonad development and lipid storage. We used high-throughput sequencing to identify genes that were differentially expressed during progression through the molt stage and then used qPCR to profile daily expression of individual genes. Based on expression profiles of twelve genes, samples were statistically clustered into three groups: (1) an early period occurring prior to separation of the cuticle from the epidermis (apolysis) when expression of genes associated with lipid synthesis and transport (FABP and ELOV) and two nuclear receptors (ERR and HR78) was highest, (2) a middle period of rapid change in both gene expression and physiological condition, including local minima and maxima in several nuclear receptors (FTZ-F1, HR38b, and EcR), and (3) a late period when gonads were differentiated and expression of genes associated with molting (Torso-like, HR38a) peaked. The ratio of Torso-like to HR38b strongly differentiated the early and late groups. CONCLUSIONS This study provides the first dynamic profiles of gene expression anchored with morphological markers of lipid accumulation, development and gonad maturation throughout a copepod molt cycle. Transcriptomic profiling revealed significant changes over the molt cycle in genes with presumed roles in lipid synthesis, molt regulation and gonad development, suggestive of a coupling of these processes in Calanus finmarchicus. Finally, we identified gene expression profiles that strongly differentiate between early and late development within the C5 copepodid stage. We anticipate that these findings and continued development of robust gene expression biomarkers that distinguish between diapause preparation and continuous development will ultimately enable novel studies of the intrinsic and extrinsic factors that govern diapause initiation in Calanus finmarchicus.
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Affiliation(s)
- Ann M Tarrant
- Biology Department, Woods Hole Oceanographic Institution, 45 Water Street, Woods Hole, MA 02543 USA
| | - Mark F Baumgartner
- Biology Department, Woods Hole Oceanographic Institution, 45 Water Street, Woods Hole, MA 02543 USA
| | - Bjørn Henrik Hansen
- SINTEF Materials and Chemistry, Environmental Technology, N-7465 Trondheim, Norway
| | | | - Trond Nordtug
- SINTEF Materials and Chemistry, Environmental Technology, N-7465 Trondheim, Norway
| | - Anders J Olsen
- Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
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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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Molecular characterization of two vitellogenin genes from the tick, Amblyomma hebraeum (Acari: Ixodidae). Ticks Tick Borne Dis 2014; 5:821-33. [DOI: 10.1016/j.ttbdis.2014.06.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 06/16/2014] [Accepted: 06/19/2014] [Indexed: 12/19/2022]
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Edvardsen RB, Dalvin S, Furmanek T, Malde K, Mæhle S, Kvamme BO, Skern-Mauritzen R. Gene expression in five salmon louse (Lepeophtheirus salmonis, Krøyer 1837) tissues. Mar Genomics 2014; 18 Pt A:39-44. [PMID: 24999079 DOI: 10.1016/j.margen.2014.06.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 06/17/2014] [Accepted: 06/21/2014] [Indexed: 11/30/2022]
Abstract
The Atlantic salmon, Salmo salar L, is an important species both for traditional fishery and fish farming. Many Atlantic salmon stocks have been declining and a suspected main contributor to this decline is the salmon louse (Lepeophtheirus salmonis); a parasitic copepod living off the salmonid hosts epidermal tissues and blood. Contributing to the growing body of knowledge on the molecular biology of the salmon louse we have utilized a microarray containing 11,100 salmon louse genes to study the gene expression patterns in selected tissues. This approach has yielded information about potential functions of the transcripts and tissues. Microarray analyses were preformed on subcuticular and frontal (neuronal and gland enriched tissue) tissues, as well as gut, ovary and testes of adult lice. Tissue specific transcriptomes were evident, allowing us to address main traits of functional partitioning between tissues and providing valuable insight into the biology of the louse. The results furthermore represent an important tool and resource for further experiments.
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Affiliation(s)
| | - Sussie Dalvin
- Institute of Marine Research, P.O. Box 1870, Nordnes, 5817 Bergen, Norway
| | - Tomasz Furmanek
- Institute of Marine Research, P.O. Box 1870, Nordnes, 5817 Bergen, Norway
| | - Ketil Malde
- Institute of Marine Research, P.O. Box 1870, Nordnes, 5817 Bergen, Norway
| | - Stig Mæhle
- Institute of Marine Research, P.O. Box 1870, Nordnes, 5817 Bergen, Norway
| | - Bjørn Olav Kvamme
- Institute of Marine Research, P.O. Box 1870, Nordnes, 5817 Bergen, Norway
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Gallardo-Escárate C, Valenzuela-Muñoz V, Nuñez-Acuña G. RNA-Seq analysis using de novo transcriptome assembly as a reference for the salmon louse Caligus rogercresseyi. PLoS One 2014; 9:e92239. [PMID: 24691066 PMCID: PMC3972170 DOI: 10.1371/journal.pone.0092239] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 02/19/2014] [Indexed: 11/22/2022] Open
Abstract
Despite the economic and environmental impacts that sea lice infestations have on salmon farming worldwide, genomic data generated by high-throughput transcriptome sequencing for different developmental stages, sexes, and strains of sea lice is still limited or unknown. In this study, RNA-seq analysis was performed using de novo transcriptome assembly as a reference for evidenced transcriptional changes from six developmental stages of the salmon louse Caligus rogercresseyi. EST-datasets were generated from the nauplius I, nauplius II, copepodid and chalimus stages and from female and male adults using MiSeq Illumina sequencing. A total of 151,788,682 transcripts were yielded, which were assembled into 83,444 high quality contigs and subsequently annotated into roughly 24,000 genes based on known proteins. To identify differential transcription patterns among salmon louse stages, cluster analyses were performed using normalized gene expression values. Herein, four clusters were differentially expressed between nauplius I–II and copepodid stages (604 transcripts), five clusters between copepodid and chalimus stages (2,426 transcripts), and six clusters between female and male adults (2,478 transcripts). Gene ontology analysis revealed that the nauplius I–II, copepodid and chalimus stages are mainly annotated to aminoacid transfer/repair/breakdown, metabolism, molting cycle, and nervous system development. Additionally, genes showing differential transcription in female and male adults were highly related to cytoskeletal and contractile elements, reproduction, cell development, morphogenesis, and transcription-translation processes. The data presented in this study provides the most comprehensive transcriptome resource available for C. rogercresseyi, which should be used for future genomic studies linked to host-parasite interactions.
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Affiliation(s)
- Cristian Gallardo-Escárate
- Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, Concepción, Chile
| | - Valentina Valenzuela-Muñoz
- Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, Concepción, Chile
| | - Gustavo Nuñez-Acuña
- Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, Concepción, Chile
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Farlora R, Araya-Garay J, Gallardo-Escárate C. Discovery of sex-related genes through high-throughput transcriptome sequencing from the salmon louse Caligus rogercresseyi. Mar Genomics 2014; 15:85-93. [PMID: 24642131 DOI: 10.1016/j.margen.2014.02.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 02/24/2014] [Accepted: 02/25/2014] [Indexed: 01/16/2023]
Abstract
Understanding the molecular underpinnings involved in the reproduction of the salmon louse is critical for designing novel strategies of pest management for this ectoparasite. However, genomic information on sex-related genes is still limited. In the present work, sex-specific gene transcription was revealed in the salmon louse Caligus rogercresseyi using high-throughput Illumina sequencing. A total of 30,191,914 and 32,292,250 high quality reads were generated for females and males, and these were de novo assembled into 32,173 and 38,177 contigs, respectively. Gene ontology analysis showed a pattern of higher expression in the female as compared to the male transcriptome. Based on our sequence analysis and known sex-related proteins, several genes putatively involved in sex differentiation, including Dmrt3, FOXL2, VASA, and FEM1, and other potentially significant candidate genes in C. rogercresseyi, were identified for the first time. In addition, the occurrence of SNPs in several differentially expressed contigs annotating for sex-related genes was found. This transcriptome dataset provides a useful resource for future functional analyses, opening new opportunities for sea lice pest control.
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Affiliation(s)
- Rodolfo Farlora
- Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, P.O. Box 160-C, Chile
| | - José Araya-Garay
- Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, P.O. Box 160-C, Chile
| | - Cristian Gallardo-Escárate
- Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, P.O. Box 160-C, Chile.
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Huo Y, Liu W, Zhang F, Chen X, Li L, Liu Q, Zhou Y, Wei T, Fang R, Wang X. Transovarial transmission of a plant virus is mediated by vitellogenin of its insect vector. PLoS Pathog 2014; 10:e1003949. [PMID: 24603905 PMCID: PMC3946389 DOI: 10.1371/journal.ppat.1003949] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 01/09/2014] [Indexed: 11/19/2022] Open
Abstract
Most plant viruses are transmitted by hemipteroid insects. Some viruses can be transmitted from female parent to offspring usually through eggs, but the mechanism of this transovarial transmission remains unclear. Rice stripe virus (RSV), a Tenuivirus, transmitted mainly by the small brown planthopper (Laodelphax striatellus), is also spread to the offspring through the eggs. Here, we used the RSV–planthopper system as a model to investigate the mechanism of transovarial transmission and demonstrated the central role of vitellogenin (Vg) of L. striatellus in the process of virus transmission into the eggs. Our data showed Vg can bind to pc3 in vivo and in vitro and colocalize in the germarium. RSV filamentous ribonucleoprotein particles (RNPs) only accumulated in the terminal filaments and pedicel areas prior to Vg expression and was not present in the germarium until Vg was expressed, where RSV RNPs and Vg had colocalized. Observations by immunoelectron microscopy (IEM) also indicated that these two proteins colocalized in nurse cells. Knockdown of Vg expression due to RNA interference resulted in inhibition of the invasion of ovarioles by RSV. Together, the data obtained indicated that RSV RNPs may enter the nurse cell of the germarium via endocytosis through binding with Vg. Finally, the virus enters the oocytes through nutritive cords, using the same route as for Vg transport. Our results show that the Vg of L. striatellus played a critical role in transovarial transmission of RSV and shows how viruses can use existing transovarial transportation systems in insect vectors for their own purposes. Numerous parasites including viruses, bacteria, and microsporidia can be maternally transmitted, with the parasite passing from mother to offspring, usually through eggs. However, the process of the parasites spreading into eggs from primarily infected tissues and the factors that mediate this process in live hosts or vectors are unknown due to the lack of useful tools. Here, we used several techniques to investigate the molecular mechanisms of transovarial transmission of Rice stripe virus (RSV), a plant virus belonging to the genus Tenuivirus, by its insect vector (Laodelphax striatellus). We found that the nucleocapsid protein of RSV bound to insect's vitellogenin (Vg) in vitro and in vivo. We also found that RSV invaded the egg tubes of the ovariole until Vg is highly expressed, then colocalized with Vg in the germarium. When Vg expression was knocked down due to RNA interference, the invasion of ovarioles by RSV decreased largely. Our study provides new insights into the transovarial transmission of an important viral pathogen that uses existing transovarial transportation systems in insect vectors to invade eggs.
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Affiliation(s)
- Yan Huo
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- National Plant Gene Research Center, Beijing, China
- Graduate School of the Chinese Academy of Sciences, Beijing, China
| | - Wenwen Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Fujie Zhang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- National Plant Gene Research Center, Beijing, China
- Graduate School of the Chinese Academy of Sciences, Beijing, China
| | - Xiaoying Chen
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- National Plant Gene Research Center, Beijing, China
| | - Li Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qifei Liu
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Yijun Zhou
- Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Taiyun Wei
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- * E-mail: (TW); (RF); (XW)
| | - Rongxiang Fang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- National Plant Gene Research Center, Beijing, China
- * E-mail: (TW); (RF); (XW)
| | - Xifeng Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- * E-mail: (TW); (RF); (XW)
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Tröße C, Nilsen F, Dalvin S. RNA interference mediated knockdown of the KDEL receptor and COPB2 inhibits digestion and reproduction in the parasitic copepod Lepeophtheirus salmonis. Comp Biochem Physiol B Biochem Mol Biol 2013; 170:1-9. [PMID: 24382395 DOI: 10.1016/j.cbpb.2013.12.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 12/18/2013] [Accepted: 12/19/2013] [Indexed: 11/29/2022]
Abstract
Retrograde transport of proteins from the endoplasmic reticulum to the Golgi is an essential part of the secretory pathway that all newly synthesised secreted and membrane proteins in eukaryotic cells undergo. The aim of this study was to characterise two components of the retrograde transport pathway in the parasitic copepod Lepeophtheirus salmonis (salmon louse) on a molecular and functional level. LsKDELR and LsCOPB2 were confirmed to be the salmon louse homologues of the chosen target proteins by sequence similarity. Ontogenetic analysis by qRT-PCR revealed the highest expression levels of both genes in adult females and the earliest larval stage. LsKDELR and LsCOPB2 localisation in adult females was detected by immunofluorescence and in situ hybridisation, respectively. Both LsKDELR and LsCOPB2 were found in the ovaries, the oocytes and the gut. LsKDELR and LsCOPB2 were knocked down by RNA interference in preadult females, which was confirmed by qRT-PCR. LsCOPB2 knockdown lice had a significantly higher mortality and failed to develop normally, while both LsCOPB2 and LsKDELR knockdown caused disturbed digestion and the absence of egg strings. This shows the potential of LsKDELR and LsCOPB2 as suitable target candidates for new pest control methods.
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Affiliation(s)
- Christiane Tröße
- Department of Biology, University of Bergen, P.O. Box 7803, 5020 Bergen, Norway.
| | - Frank Nilsen
- SLRC-Sea Lice Research Centre, Department of Biology, University of Bergen, P.O. Box 7803, 5020 Bergen, Norway
| | - Sussie Dalvin
- SLRC-Sea Lice Research Centre, Institute of Marine Research, P.O. Box 1870, 5817 Bergen, Norway
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Sun C, Hu L, Liu S, Gao Z, Zhang S. Functional analysis of domain of unknown function (DUF) 1943, DUF1944 and von Willebrand factor type D domain (VWD) in vitellogenin2 in zebrafish. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2013; 41:469-476. [PMID: 23867754 DOI: 10.1016/j.dci.2013.07.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 07/06/2013] [Accepted: 07/08/2013] [Indexed: 06/02/2023]
Abstract
Vitellogenin (Vg), the precursor of egg-yolk proteins in all oviparous organisms, shares a similar domain structure combination. In most cases, Vg contains the Vitellogenin_N domain, the domain of unknown function (DUF) 1943, and the von Willebrand factor type D domain (VWD), which are present in different forms of Vg from both vertebrates and invertebrates. Occasionally, a DUF1944 domain is also present in between DUF1943 and VWD in some Vg proteins of vertebrates. Recent studies have shown that Vg participates in immune defense of host with multiple functions. However, whether all Vg proteins encoded by different vg genes play an immune role is unknown. In addition, the correlation of different domains in Vg with the multiple immune functions remains completely unclear. Here we demonstrated clearly that recombinant proteins, rDUF1943, rDUF1944 and rVWD from zebrafish Vg2 interacted with both the Gram-positive bacteria Staphylococcus aureus, Bacillus subtilis and Micrococcus luteus and the Gram-negative bacteria Escherichia coli and Vibrio anguillarum, as well as their signature components LTA and LPS. Moreover, both rDUF1943 and rDUF1944 promoted the phagocytosis of E. coli and S. aureus by carp macrophages. These suggest that both DUF1943 and DUF1944 as well as VWD may contribute to the function of Vg as a pattern recognition receptor, and DUF1943 and DUF1944 also contribute to the function of Vg as an opsonin. This study also opens a new angle for identification of function of genes of unknown function, which have the domains DUF1943 and DUF1944.
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Affiliation(s)
- Chen Sun
- Laboratory for Evolution & Development, Institute of Evolution & Marine Biodiversity and Department of Marine Biology, Ocean University of China, Qingdao 266003, China
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The Salmon Louse Lepeophtheirus salmonis (Copepoda: Caligidae) life cycle has only two Chalimus stages. PLoS One 2013; 8:e73539. [PMID: 24069203 PMCID: PMC3772071 DOI: 10.1371/journal.pone.0073539] [Citation(s) in RCA: 171] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 07/19/2013] [Indexed: 11/19/2022] Open
Abstract
Each year the salmon louse (Lepeophtheirussalmonis Krøyer, 1838) causes multi-million dollar commercial losses to the salmon farming industry world-wide, and strict lice control regimes have been put in place to reduce the release of salmon louse larvae from aquaculture facilities into the environment. For half a century, the Lepeophtheirus life cycle has been regarded as the only copepod life cycle including 8 post-nauplius instars as confirmed in four different species, including L. salmonis. Here we prove that the accepted life cycle of the salmon louse is wrong. By observations of chalimus larvae molting in incubators and by morphometric cluster analysis, we show that there are only two chalimus instars: chalimus 1 (comprising the former chalimus I and II stages which are not separated by a molt) and chalimus 2 (the former chalimus III and IV stages which are not separated by a molt). Consequently the salmon louse life cycle has only six post-nauplius instars, as in other genera of caligid sea lice and copepods in general. These findings are of fundamental importance in experimental studies as well as for interpretation of salmon louse biology and for control and management of this economically important parasite.
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Dalvin S, Nilsen F, Skern-Mauritzen R. Localization and transcription patterns of LsVasa, a molecular marker of germ cells inLepeophtheirus salmonis(Krøyer). J NAT HIST 2013. [DOI: 10.1080/00222933.2012.738830] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Akasaka M, Kato KH, Kitajima K, Sawada H. Identification of Novel Isoforms of Vitellogenin Expressed in Ascidian Eggs. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2013; 320:118-28. [DOI: 10.1002/jez.b.22488] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Revised: 12/13/2012] [Accepted: 12/19/2012] [Indexed: 11/06/2022]
Affiliation(s)
| | - Koichi H. Kato
- Graduate School of Natural Sciences; Nagoya City University, Mizuho-ku; Nagoya; Japan
| | - Ken Kitajima
- Bioscience and Biotechnology Center; Nagoya University; Nagoya; Japan
| | - Hitoshi Sawada
- Sugashima Marine Biological Laboratory; Graduate School of Science, Nagoya University, Sugashima; Toba; Japan
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