Project description:The long-term viability of Pacific salmon stocks and the fisheries they support are threatened if large numbers die prematurely en-route to spawning grounds. Physiological profiles that were correlated with the fate of wild sockeye salmon during river migration were discovered using functional genomics studies on biopsied tissues. Three independent biotelemetry studies tracked the biopsied fish after tagging in the marine environment over 200 km from the Fraser River, in the lower river 69 km from the river mouth and at the spawning grounds. Salmon carrying the poor performance (unhealthy) profile in the ocean exhibited a 4-times lower probability of arriving to spawning grounds than those with a healthy genomic signature, although generally migrated into the river and to the spawning grounds faster. A related unhealthy signature observed in the river was associated with a 30% reduction in survival to spawning grounds in one of the three stocks tested. At spawning grounds, the same poor performance signature was associated with twice the pre-spawning mortality compared with healthy fish. Functional analysis revealed that the unhealthy signature, which intensified during migration to spawning grounds, was consistent with an intracellular pathogenic infection, likely a virus. These results are the first to suggest a pathogen present in salmon in the marine environment could be a major source of mortality during migration and spawning in the river. This series is of gill expression profiles from the study of fish sampled and tagged in the ocean and tracked as they entered the river system and swam towards the spawning grounds. Fish were caught in seine nets, gastrically implanted with radio transmitters, and biopsy sampled for blood, gill, muscle, and fin. Individual fish were tracked by receivers placed throughout the Fraser River watershed to identify and fate (i.e. the location of the receiver that last detected the fish). Targeted stocks of interest were genetically identified. Gene expression was profiled in gill tissue, a critical respiratory and ionoregulatory organ that is highly responsive to stress, chemical exposure and disease. Gene expression was assayed on the GRASP salmonid 16K cDNA microarray.

Project description:The long-term viability of Pacific salmon stocks and the fisheries they support are threatened if large numbers die prematurely en-route to spawning grounds. Physiological profiles that were correlated with the fate of wild sockeye salmon during river migration were discovered using functional genomics studies on biopsied tissues. Three independent biotelemetry studies tracked the biopsied fish after tagging in the marine environment over 200 km from the Fraser River, in the lower river 69 km from the river mouth and at the spawning grounds. Salmon carrying the poor performance (unhealthy) profile in the ocean exhibited a 4-times lower probability of arriving to spawning grounds than those with a healthy genomic signature, although generally migrated into the river and to the spawning grounds faster. A related unhealthy signature observed in the river was associated with a 30% reduction in survival to spawning grounds in one of the three stocks tested. At spawning grounds, the same poor performance signature was associated with twice the pre-spawning mortality compared with healthy fish. Functional analysis revealed that the unhealthy signature, which intensified during migration to spawning grounds, was consistent with an intracellular pathogenic infection, likely a virus. These results are the first to suggest a pathogen present in salmon in the marine environment could be a major source of mortality during migration and spawning in the river. This series are gill expression profiles from the study of fish sampled and tagged in the lower river and tracked as they swam towards the spawning grounds. Fish were caught in seine nets, gastrically implanted with radio transmitters, and biopsy sampled for blood, gill, muscle, and fin. Individual fish were tracked by receivers placed throughout the Fraser River watershed to identify and fate (i.e. the location of the receiver that last detected the fish). Targeted stocks of interest were genetically identified. Gene expression was profiled in gill tissue, a critical respiratory and ionoregulatory organ that is highly responsive to stress, chemical exposure and disease. Gene expression was assayed on the GRASP salmonid 16K cDNA microarray.

Project description:The long-term viability of Pacific salmon stocks and the fisheries they support are threatened if large numbers die prematurely en-route to spawning grounds. Physiological profiles that were correlated with the fate of wild sockeye salmon during river migration were discovered using functional genomics studies on biopsied tissues. Three independent biotelemetry studies tracked the biopsied fish after tagging in the marine environment over 200 km from the Fraser River, in the lower river 69 km from the river mouth and at the spawning grounds. Salmon carrying the poor performance (unhealthy) profile in the ocean exhibited a 4-times lower probability of arriving to spawning grounds than those with a healthy genomic signature, although generally migrated into the river and to the spawning grounds faster. A related unhealthy signature observed in the river was associated with a 30% reduction in survival to spawning grounds in one of the three stocks tested. At spawning grounds, the same poor performance signature was associated with twice the pre-spawning mortality compared with healthy fish. Functional analysis revealed that the unhealthy signature, which intensified during migration to spawning grounds, was consistent with an intracellular pathogenic infection, likely a virus. These results are the first to suggest a pathogen present in salmon in the marine environment could be a major source of mortality during migration and spawning in the river. This series are gill expression profiles from the study of fish at the Weaver creek spawning grounds, and were observed for pre-spawning mortality or successful spawning. Weaver creek sockeye salmon (a late-run stock) spawn in an artificial spawning channel which has a controlled entrance and no exit, situated 100 km from the ocan. Females were dip-netted out of the entrance of the spawning channel, and placed into a sampling trough with flowing ambient water for the gill biopsy procedure and tagged with Petersen discs and returned to the spawning channel. Moribund fish were recovered daily and their gonads examined to assess whether they had spawned or not. Gene expression was assayed on the GRASP salmonid 32K cDNA microarray.

Project description:Mycotoxins are secondary metabolites which are produced by numerous fungi and pose a continuous challenge to the safety and quality of food commodities in South Africa. These toxins have toxicologically relevant effects on humans and animals that eat contaminated foods. In this study, a diagnostic DNA microarray was developed for the identification of the most common food-borne fungi, as well as the genes leading to toxin production. A total of 40 potentially mycotoxigenic fungi isolated from different food commodities, as well as the genes that are involved in the mycotoxin synthetic pathways, were analyzed. For fungal identification, oligonucleotide probes were designed by exploiting the sequence variations of the elongation factor 1-alpha (EF-1 Î±) coding regions and the internal transcribed spacer (ITS) regions of the rRNA gene cassette. For the detection of fungi able to produce mycotoxins, oligonucleotides directed towards genes leading to toxin production from different fungal strains were identified in data available in the public domain. The oligonucleotides selected for fungal identification and the oligonucleotides specific for toxin producing genes were spotted onto microarray slides. The diagnostic microarray developed can be used to identify potentially mycotoxigenic fungi as well as genes leading to toxin production in both laboratory and food samples offering an interesting potential for microbiological laboratories. Keywords: Development of a diagnostic microarray for the identification of potentially mycotoxigenic fungi as well as genes leading to toxin production, 40 food-borne fungi, mycotoxins Development of a diagnostic array for the identification of food-borne fungi and their potential mycotoxin-producing genes. Oligonucleotide probes to be printed onto the array were designed by exploiting the sequence variations of the elongation factor 1-alpha (EF-1 Î±) coding regions and the internal transcribed spacer (ITS) regions of the rRNA gene cassette. For the detection of fungi able to produce mycotoxins, oligonucleotides directed towards genes leading to toxin production from different fungal strains were identified in data available in the public domain. Analysis was performed with 40 fungal cultures were obtained from the Agricultural Research Council culture collection (ARC), Pretoria, South Africa.an in-house spotted oligonucleotide microarray. The identity of each fungus was confirmed by standard laboratory procedures. For DNA isolation, the fungal strains were grown on 1.5% malt extract agar at 25Â°C for 1-2 weeks and total genomic fungal DNA was extracted following the DNA extraction protocol described by Raeder and Broda (1985). The internal transcribed spacer oligonucleotides ITS1, ITS3 and ITS4 were used as a reference for normalization of all spot intensity data.Samples were fluorescently labelled with Cy5 dye by using a Cyâ¢Dye Post-labelling Reactive Dye Pack and wre hybridized to the oligonucleotide microarray overnight. Two biological and one technical replicate (using independent labelling reactions) was performed, each replication consisting of a reverse labelling experiment.

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Transcriptomic responses to high water temperature in Pacific salmon

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