title: Transcriptome survey of the lipid metabolic pathways involved in energy production and ecdysteroid synthesis in the salmon louse Caligus rogercresseyi (Crustacea: Copepoda).
abstract: The goal of this study was to identify and analyze the lipid metabolic pathways involved in energy production and ecdysteroid synthesis in the ectoparasite copepod Caligus rogercresseyi. Massive transcriptome sequencing analysis was performed during the infectious copepodid larval stage, during the attached chalimus larval stage, and also in female and male adults. Thirty genes were selected for describing the pathways, and these were annotated for proteins or enzymes involved in lipid digestion, absorption, and transport; fatty acid degradation; the synthesis and degradation of ketone bodies; and steroid and ecdysteroid syntheses. Differential expression of these genes was analyzed by ontogenic stage and discussed considering each stage's feeding habits and energetic needs. Copepodids showed a low expression of fatty acid digestion genes, reflected by a non-feeding behavior, and the upregulation of genes involved in steroid biosynthesis, which was consistent with a pathway for cholesterol synthesis during ecdysis. The chalimus stage showed an upregulation of genes related to fatty acid digestion, absorption, and transport, as well as to fatty acid degradation and the synthesis of ketone bodies, therefore suggesting that lipids ingested from the mucus and skin of the host fish are metabolized as important sources of energy. Adult females also showed a pattern of high lipid metabolism for energy supply and mobilization in relation to reproduction and vitellogenesis. Adult females and males revealed different lipid metabolism patterns that reflected different energetic needs. This study reports for the first time the probable lipid metabolic pathways involved in the energy production and ecdysteroid synthesis of C. rogercresseyi.
authors: Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, P.O. Box 160-C, Chile. Electronic address: ateresagoncalves@oceanografia.udec.cl.
authors: Ana Teresa
authors: AT
authors: Gonçalves
authors: Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, P.O. Box 160-C, Chile. Electronic address: rfarlora@oceanografia.udec.cl.
authors: Rodolfo
authors: R
authors: Farlora
authors: Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, P.O. Box 160-C, Chile. Electronic address: crisgallardo@udec.cl.
authors: Cristian
authors: C
authors: Gallardo-Escárate
mesh_terms: D000818:Animals; D003198:Computer Simulation; D033342:Copepoda / Q000378:metabolism*; D026461:Ecdysteroids / Q000096:biosynthesis*; D004734:Energy Metabolism / Q000235:genetics*; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D059014:High-Throughput Nucleotide Sequencing; D007657:Ketone Bodies / Q000378:metabolism; D007814:Larva / Q000378:metabolism; D008018:Life Cycle Stages / Q000235:genetics; D050356:Lipid Metabolism / Q000235:genetics*; D008297:Male; D053858:Metabolic Networks and Pathways / Q000235:genetics; D058977:Molecular Sequence Annotation; D018978:Molting / Q000235:genetics; D012098:Reproduction / Q000235:genetics; D020317:Salmo salar / Q000469:parasitology*; D012737:Sex Factors; D059467:Transcriptome
chemical_list: D026461:Ecdysteroids; D005227:Fatty Acids; D007657:Ketone Bodies
keywords: Caligus rogercresseyi; Cholesterol synthesis; Ecdysis; Ecdysteroid synthesis; RNA-seq analysis