Investigating the molecular basis for resistance to the sea louse, Lepeophtheirus salmonis, among salmonids

dc.contributor.authorBraden, Laura Marie
dc.contributor.supervisorJones, Simon
dc.contributor.supervisorKoop, Benjamin F.
dc.date.accessioned2015-04-17T20:26:44Z
dc.date.available2016-03-27T11:22:08Z
dc.date.copyright2015en_US
dc.date.issued2015-04-17
dc.degree.departmentDepartment of Biology
dc.degree.levelDoctor of Philosophy Ph.D.en_US
dc.description.abstractCo-evolution between parasites and their hosts result in extremely well-orchestrated and intimate relationships that are characterized by remarkable adaptations in the attack response of the parasite and the defense response of the host. To fully understand host-parasite interactions, these adaptations must be considered in the context of the ecological constraints in which they evolved. As a serious pest to salmon mariculture, Lepeophtheirus salmonis has been extensively studied; however, there are still several areas that require further research. Of utmost importance, and the topic of this thesis, is molecular basis for resistance to sea lice. The following chapters investigate this phenomena under the umbrella of ecological immunology using combined modern technologies of transcriptomics, proteomics and functional immunology with a focus on the primary interaction site. In the first chapter, I describe the key players involved in this host-parasite relationship with a focus on the primary interaction site, the louse-salmon interface, where there are responses by the louse (attack) and the salmon host (defense). Previous research indicated that an early aggressive inflammatory response at the louse-skin interface contributes to resistance in coho salmon; however, there are no data characterizing a site-specific response in resistant (pink and coho) and susceptible (Atlantic, chum) species. Accordingly in Chapter 2, I define site-specific cutaneous responses in Atlantic, pink and chum salmon to establish genetic biomarkers of resistance. Chapter 3 focuses on identification of cellular effectors using histochemical localization of biomarkers to characterize cellular populations activated at the louse-attachment site, while broadening the gene targets. Our notion of pink salmon as a resistant species is challenged by the common observation of migrating pink salmon supporting large populations of L. salmonis in the field. Thus the purpose of chapter 4 was to investigate potential mechanisms to explain variations in susceptibility as a function of life history. Host-parasite relationships are a product of both host and parasite responses; therefore, in chapters 5 and 6, I shift focus to the level of the parasite. In chapter 5 I present the first documented large-scale transcriptomic profiling of L. salmonis during feeding on both resistant (coho) and susceptible (Atlantic, sockeye) salmon. This was followed (chapter 6) by describing the proteomic profile of L. salmonis secretions after feeding on Atlantic salmon. In the seventh and final chapter, I present my conclusions on the molecular mechanisms for resistance to sea lice and discuss potential applications of this information for future louse control strategies.en_US
dc.description.scholarlevelGraduateen_US
dc.identifier.bibliographicCitationBraden LM, Barker DE, Koop BF, Jones SRM (2012) Comparative defense-associated responses in salmon skin elicited by the ectoparasite Lepeophtheirus salmonis. Comparative Biochemistry and Physiology. Part D, Genomics & Proteomics, 7, 100–9.en_US
dc.identifier.bibliographicCitationBraden LM, Koop BF, Jones SRM (2015) Signatures of resistance to Lepeophtheirus salmonis include a Th2-type response at the louse-salmon interface. Developmental & Comparative Immunology, 48, 178–191.en_US
dc.identifier.urihttp://hdl.handle.net/1828/5978
dc.languageEnglisheng
dc.language.isoenen_US
dc.rightsAvailable to the World Wide Weben_US
dc.rights.tempAvailable to the World Wide Weben_US
dc.rights.tempAttribution-NonCommercial-ShareAlike 2.5 Canada*
dc.rights.urihttp://creativecommons.org/licenses/by-nc-sa/2.5/ca/*
dc.subjectImmunohistochemistryen_US
dc.subjectTranscriptomicsen_US
dc.subjectLepeophtheirus salmonisen_US
dc.subjectOncorhynchus gorbuschaen_US
dc.subjectSalmo salaren_US
dc.subjectOncorhynchus ketaen_US
dc.subjectOncorhynchus nerkaen_US
dc.subjectOncorhynchus kisutchen_US
dc.subjectSalmonen_US
dc.subjectInflammatory responseen_US
dc.subjectHost-parasite interactionsen_US
dc.subjectResistanceen_US
dc.titleInvestigating the molecular basis for resistance to the sea louse, Lepeophtheirus salmonis, among salmonidsen_US
dc.typeThesisen_US

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