Project description:This SuperSeries is composed of the following subset Series: GSE26981: Responses to ectoparasite salmon louse (Lepeophtheirus salmonis) in skin of Atlantic salmon GSE26984: Responses to ectoparasite salmon louse (Lepeophtheirus salmonis) in spleen of Atlantic salmon Refer to individual Series

2011-02-03 | E-GEOD-27013 | biostudies-arrayexpress

Institute of Aquaculture Lepeophtheirus salmonis analysis of gene expression induced by in vitro exposure to emamectin benzoate

Project description:Caligid copepods, also called sea lice, are common ectoparasites of wild and farmed marine fish. The salmon louse Lepeophtheirus salmonis (KrM-xyer, 1837) has emerged as a serious problem for salmon farming in the Northern hemisphere. The annual cost of sea lice to the global salmon mariculture industry has been estimated at M-^@300 million, of which the majority accounts for the cost of chemically treating the farmed salmon. The treatments available for salmonids with sea lice infestation have been limited with a large scale reliance on single products and the use of antiparasitics with similar modes of action, which when used over a long period of time can enhance the selection pressure for reduced sensitivity. The aim of the present study was to identify transcripts whose expression correlated to emamectin benzoate (EMB) susceptibility, or those genes regulated in response to EMB exposure. Two L. salmonis laboratory strains, established from field isolates and differing in susceptibility to EMB were studied using a custom sea louse 15K oligonucleotide microarray and RT-qPCR. Adult male sea lice were sampled from both strains after 1 and 3 hours of aqueous exposure to 0.2 M-5g mL-1 emamectin benzoate, 0.01% PEG300 or sea water. Bioinformatic analysis identified that in the absence of drug treatment, a large number of genes were significantly down regulated in the louse strain hyposensitive to EMB. EMB exposure had marked effects on gene expression in the EMB susceptible strain, but caused little changes in EMB hyposensitive lice. We therefore suggest that transcriptional responses induced by EMB exposure may not be responsible for reduced susceptibility to this antiparasitic compound, but may involve genes that are constitutively expressed in EMB tolerant salmon louse strains.

2013-11-06 | E-MTAB-1478 | biostudies-arrayexpress

Lepeophtheirus nordmannii

Project description:Lepeophtheirus nordmannii overview

| PRJNA1044900 | ENA

Keratinocytes Drive the Epithelial Hyperplasia Key to Sea Lice Resistance in Coho Salmon

Project description:Background: Salmonid species have followed markedly divergent evolutionary trajectories in their interactions with sea lice. While sea lice parasitism poses significant economic, environmental, and animal welfare challenges for Atlantic salmon (Salmo salar) aquaculture, coho salmon (Oncorhynchus kisutch) exhibit near-complete resistance to sea lice, achieved through a potent epithelial hyperplasia response leading to rapid louse detachment. The molecular mechanisms underlying these divergent responses to sea lice are unknown. Results: We characterised the cellular and molecular responses of Atlantic salmon and coho salmon to sea lice using single-nuclei RNA sequencing. Juvenile fish were exposed to copepodid sea lice (Lepeophtheirus salmonis), and lice-attached pelvic fin and skin samples were collected 12h, 24h, 36h, 48h, and 60h after exposure, along with control samples. Comparative analysis of control and treatment samples revealed an immune and wound-healing response that was common to both species, but attenuated in Atlantic salmon, potentially reflecting greater sea louse immunomodulation. Our results revealed unique but complementary roles of three layers of keratinocytes in the epithelial hyperplasia response leading to rapid sea lice rejection in coho salmon. Our results suggest that basal keratinocytes direct the expansion and mobility of intermediate and, especially, superficial keratinocytes, which eventually encapsulate the parasite. Conclusions: Our results highlight the key role of keratinocytes in coho salmon’s sea lice resistance, and the diverged biological response of the two salmonid host species when interacting with this parasite. This study has identified key pathways and candidate genes that could be manipulated using various biotechnological solutions to improve Atlantic salmon sea lice resistance.

2024-06-24 | GSE269132 | GEO

RNAi knock down of maternal yolk associated protein (LsYAP) in the salmon louse Lepeophtheirus salmonis

Project description:Characterisation of the maternal yolk associated protein (LsYAP) and establishment of systemic RNA interference in the salmon louse (Lepeophtheirus salmonis) (Crustacea, Copepoda)

2009-04-21 | E-TABM-685 | biostudies-arrayexpress

Institute of Aquaculture Lepeophtheirus salmonis constitutive gene expression analysis

Project description:Caligid copepods, also called sea lice, are common ectoparasites of wild and farmed marine fish. The salmon louse Lepeophtheirus salmonis (KrM-xyer, 1837) has emerged as a serious problem for salmon farming in the Northern hemisphere. The annual cost of sea lice to the global salmon mariculture industry has been estimated at M-^@300 million, of which the majority accounts for the cost of chemically treating the farmed salmon. The treatments available for salmonids with sea lice infestation have been limited with a large scale reliance on single products and the use of antiparasitics with similar modes of action, which when used over a long period of time can enhance the selection pressure for reduced sensitivity. Two L. salmonis laboratory strains, established from field isolates and differing in susceptibility to emamectin benzoate (EMB) were studied using a custom sea louse 15K oligonucleotide microarray and RT-qPCR. The aim of the present study was to identify differential expression of transcripts between these two strains to identify potential constitutive gene expression changes associated with reduced susceptibility to EMB. Adult male salmon lice were sampled without exposure to antiparasitic agents for the purpose of studying gene expression from unchallenged individuals. In this study changes in expression of Glutamate-gated Chloride channel (GluCl) subunits, considered the major target site for avermectin (AVM) drugs in invertebrates, was not observed, but expression changes were seen for alternative ligand-gated ion channel (LGIC) subunits that form an ion channels shown to interact with AVMs in vertebrates, but which is not traditionally considered to be a target site for AVMs in invertebrates. We hypothesise that these LGIC subunits represent additional EMB target sites in salmon lice, and that the down-regulation of these channel subunits in this EMB-resistant strain is related to the resistance phenotype.

2013-11-06 | E-MTAB-1484 | biostudies-arrayexpress

Lepeophtheirus salmonis

Project description:Lepeophtheirus salmonis (salmon louse) overview

| PRJNA43643 | ENA