Project description:This is the first use of cDNA microarrays to study the influence of GH transgenesis on liver gene expression in a non-mammalian vertebrate. Three groups of salmon were examined: transgenic on full ration (T), transgenic on restricted ration (R), and control nontransgenic (C). Daily weight gains in T were approximately 8-fold higher than in C, and 4-fold higher than in R. Differential gene expression in T, R, and C samples was determined using ~ 16,000 gene microarrays. In the GRASP microarray studies, only those features (cDNA spots on the microarrays) behaving similarly (e.g. greater than 2-fold up-regulated in T relative to C) in all slides of the study will be reported to minimize false positives occurring due to dye bias and technical variability. Coho salmon transcripts responding reproducibly to GH transgenesis with and without feed rationing will be reported. Many of the microarray-identified hepatic transcripts responsive to GH transgenesis with and without rationing are involved in iron homeostasis, metabolism, cellular proliferation, and innate immunity. Keywords: Impact of growth hormone transgenesis with and without ration restriction on global hepatic gene expression
Project description:The influence of GH transgenesis on liver gene expression in coho salmon was examined. Gene expression in livers of transgenic salmon on a restricted ration (R) was compared to that in livers of nontransgenic control salmon (C). Keywords: Transcript profile
Project description:By directly comparing gene expression in wild type, domestic, and GH transgenic strains of salmon, we have found that domestication and GH transgenesis are modifying similar genetic pathways. Genes in many different physiological pathways show modified expression in domestic and GH transgenic strains relative to wild-type, but effects are strongly correlated. Genes specifically involved in growth regulation (IGF-I, GHR, IGF-II, THR) are also concordantly regulated in domestic and transgenic fish, and both strains show elevated levels of circulating IGF-I. Muscle expression of GH in nontransgenic strains was found to be elevated in domesticated fish relative to wild type, providing a possible mechanism for growth enhancement. These data have implications for genetic improvement of existing domesticated species as well as regulation of emerging transgenic strains. Keywords: Expression profiling by array Microarray analyses were performed on four or five individual fish per group of wild type, domesticated, and GH transgenic salmon hybridized (one slide per individual) against a common wild-type RNA pool.
Project description:By directly comparing gene expression in wild type, domestic, and GH transgenic strains of salmon, we have found that domestication and GH transgenesis are modifying similar genetic pathways. Genes in many different physiological pathways show modified expression in domestic and GH transgenic strains relative to wild-type, but effects are strongly correlated. Genes specifically involved in growth regulation (IGF-I, GHR, IGF-II, THR) are also concordantly regulated in domestic and transgenic fish, and both strains show elevated levels of circulating IGF-I. Muscle expression of GH in nontransgenic strains was found to be elevated in domesticated fish relative to wild type, providing a possible mechanism for growth enhancement. These data have implications for genetic improvement of existing domesticated species as well as regulation of emerging transgenic strains. Keywords: Expression profiling by array
Project description:RNAseq analysis of fast skeletal muscle in restriction-fed transgenic Coho salmon (Oncorhynchus kisutch): an experimental model uncoupling the growth hormone and nutritional signals regulating growth.
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.
Project description:This study investigates host-specific gene expression of the Pacific salmon lice, Lepeophtheirus salmonis oncorhynchii, while parasitizing a resistant host (Coho salmon), two susceptible hosts (Atlantic salmon, Sockeye salmon), and a population with-held hosts (starved), over 48 hrs.
Project description:Exposure to environmental concentrations of organophosphate pesticides in Pacific salmon can cause neurobehavioral injuries leading to loss of survival. However, the molecular mechanisms underlying olfactory impairment remain poorly understood. In the current study, we exposed juvenile salmon to three environmentally-relevant doses of chlorpyrifos (CPF) and malathion (MAL) individually and to three concentrations of binary mixtures of both compounds. Brain acetylcholinesterase (AChE) activity was significantly reduced only in the highest dosage of binary mixture group (47% inhibition). Microarray analysis on RNA from coho olfactory rosettes revealed a number of differentially expressed genes in all exposure groups. Overall, there were little overlapping of affected canonical pathways between CPF groups and MAL groups, suggesting the different biofunctions targeted by these two OP pesticides. Several metabolic and signaling pathways also represented the significant toxicological impact of OP pesticides on olfactory system, such as Aryl Hydrocarbon Receptor Signaling, Xenobiotic Metabolism Signaling, Mitochondrial Dysfunction, Pro-Apoptosis, and Oxidative Stress.