Project description:We collected sockeye salmon from the Fraser River, British Columbia, and held them at ecologically relevant temperatures (14C and 19C) determine the effect of elevated water temperature on cellular processes in non-lethally sampled gill tissue and blood plasma over a period of seven days that represents a significant portion of their upstream migration. Time-matched fish that died prematurely over the course of the holding study were also sampled for gill tissue and the transcriptomic responses in moribund fish were compared with surviving fish. This is the first study to experimentally examine transcriptomic responses to high water temperature and premature mortality in wild-caught Pacific salmon and the results will help in understanding some of the cellular mechanisms involved in large-scale migration mortality in Pacific salmon during warm water periods and for predicting or understanding causes of mortality in naturally senescing adult Pacific salmon.
Project description:Gilthead sea bream fed plant-protein based diets with either fish oil or vegetable oil as the most iportant source of dietary lipids were experimentally exposed to the intestinal parasite Enteromyxum leei by water effluent. A specific gilthead sea bream oligo-microarray was used to determine the intestine transcriptomic response.
Project description:We collected sockeye salmon from the Fraser River, British Columbia, and held them at ecologically relevant temperatures (14C and 19C) determine the effect of elevated water temperature on cellular processes in non-lethally sampled gill tissue and blood plasma over a period of seven days that represents a significant portion of their upstream migration. Time-matched fish that died prematurely over the course of the holding study were also sampled for gill tissue and the transcriptomic responses in moribund fish were compared with surviving fish. This is the first study to experimentally examine transcriptomic responses to high water temperature and premature mortality in wild-caught Pacific salmon and the results will help in understanding some of the cellular mechanisms involved in large-scale migration mortality in Pacific salmon during warm water periods and for predicting or understanding causes of mortality in naturally senescing adult Pacific salmon. Forty samples were analyzed on forty two-channel microarrays, using a common reference design, with multiple biological replicates for each temperature condition. Fish were further classified into survivor and moribund based on their status after 7 days in captivity.
Project description:The main findings of the current study were that exposing adult sockeye salmon Oncorhynchus nerka to a warm temperature that they regularly encounter during their river migration induced an mRNA-level heat shock response that is exacerbated with swimming. Similar immune defense-related responses were also observed. Microarray analyses revealed that 347 genes were differentially expressed between the cold (12-13M-BM-0 C) and warm (18-19M-BM-0 C) treated fish (P < 0.01), with stress response (GO:0006950; P = 0.014) and response to fungus (GO:0009620; P = 0.003) elevated with warm treatment, while expression for genes involved in oxidative phosphorylation (GO:0006119; P = 0.0019) and electron transport chain (GO:0022900; P = 0.00043) increased in cold-treated fish. By studying single genes with RT-qPCR, warm treatment fish from the Chilko population of O. nerka induced expression of heat shock protein (hsp) 90M-NM-1, hsp90M-NM-2 and hsp30, as well as interferon-inducible protein (P < 0.05). A Nechako population of O. nerka with a narrower thermal tolerance window than the Chilko population showed even more pronounced responses to the warm treatment. In conclusion, it appears that during their once-in-the-lifetime migration these adult sockeye salmon encounter conditions that induce several cellular defense mechanisms. As river temperatures continue to increase, it remains to be seen whether or not these cellular defenses provide enough protection for all sockeye salmon populations. Two condition experiment; cold treated fish vs. warm treated fish, n=4 in both group
Project description:Chemical signals are produced by aquatic organisms following predatory attacks or perturbations such as parasitic infection. Ectoparasites feeding on host fish are likely to cause release of similar alarm cues into the environment due to the stress, wounding and immune response stimulated upon infection. Alarm cues are often released in the form of proteins and peptides and provide important insights into bodily function and infection status. Here we outline a non-invasive method to identify potential chemical cues associated with infection in fish by extracting, purifying and characterizing proteins from water samples from cultured fish. Gel free proteomic methods were deemed the most suitable for protein detection in saline water samples. It was confirmed that proteins could be characterized from teleost water samples and that variation in protein profiles could be detected between infected and uninfected individuals and fish and parasite only water samples. Our novel assay provides a non-invasive method for assessing the health condition of both wild and farmed aquatic organisms. Similar to environmental DNA monitoring methods, these proteomic techniques could provide an important tool in applied biology and aquaculture biology
Project description:The main findings of the current study were that exposing adult sockeye salmon Oncorhynchus nerka to a warm temperature that they regularly encounter during their river migration induced an mRNA-level heat shock response that is exacerbated with swimming. Similar immune defense-related responses were also observed. Microarray analyses revealed that 347 genes were differentially expressed between the cold (12-13° C) and warm (18-19° C) treated fish (P < 0.01), with stress response (GO:0006950; P = 0.014) and response to fungus (GO:0009620; P = 0.003) elevated with warm treatment, while expression for genes involved in oxidative phosphorylation (GO:0006119; P = 0.0019) and electron transport chain (GO:0022900; P = 0.00043) increased in cold-treated fish. By studying single genes with RT-qPCR, warm treatment fish from the Chilko population of O. nerka induced expression of heat shock protein (hsp) 90α, hsp90β and hsp30, as well as interferon-inducible protein (P < 0.05). A Nechako population of O. nerka with a narrower thermal tolerance window than the Chilko population showed even more pronounced responses to the warm treatment. In conclusion, it appears that during their once-in-the-lifetime migration these adult sockeye salmon encounter conditions that induce several cellular defense mechanisms. As river temperatures continue to increase, it remains to be seen whether or not these cellular defenses provide enough protection for all sockeye salmon populations.
Project description:Gilthead sea bream fed plant-protein based diets with either fish oil or vegetable oil as the most iportant source of dietary lipids were experimentally exposed to the intestinal parasite Enteromyxum leei by water effluent. A specific gilthead sea bream oligo-microarray was used to determine the intestine transcriptomic response. 41 samples from six experimental groups (2 diets x 3 infective status) in a single-color hybridization
Project description:Circulating plasma microRNAs (miRNAs) are well established as biomarkers of several diseases in humans and have recently been used as indicators of environmental exposures in fish. However, the role of plasma miRNAs in regulating acute stress responses in fish is largely unknown. Tissue and plasma miRNAs have recently been associated with excreted miRNAs in humans however external miRNAs have never been measured in fish. The objective of this study was to characterize the plasma miRNA profile in response to acute stress in rainbow trout (Oncorhynchus mykiss), as well as miRNA profiles in novel external samples, (fish epidermal mucus and the surrounding water). RNA was extracted and sequenced from plasma, mucus, and water collected from rainbow trout and their surrounding environment prior to and one-hour following a three-minute air exposure, a known inducer of an acute stress response in fish. Following small RNA-Seq and pathway analysis, we identified differentially expressed plasma miRNAs that targeted biosynthetic, degradation, and metabolic pathways. We successfully isolated miRNA from trout mucus and the surrounding water and detected differences in miRNA expression one-hour post air stress. The altered miRNA profiles in mucus and water were unique to the altered plasma miRNA profile, indicating that the plasma miRNA response was not associated with or immediately reflected in external samples. This research expands our understanding of the role of plasma miRNA in the acute stress response of fish and is the first study to report on the successful isolation and profiling of miRNA from fish mucus and water samples. Measurements of miRNA from plasma, mucus, and water can be further studied and have the potential to be applied in environmental monitoring as non-lethal indicators of acute stress in fish.