Project description:We investigated ecotoxicological effects and toxicogenomic responses in fathead minnows (Pimephales promelas) exposed to an environmentally-relevant concentration (0.83 mg/L) of the munitions compound cyclotrimethylenetrinitramine (RDX) in one year and multi-generational assays. In the one year assay, RDX effects were discerned by comparing breeding groups reared in control or RDX-exposure conditions for one year. RDX had no detectable effect on gonad-somatic index, or condition factor in females assayed at 1 day and at 1, 3, 6, 9, and 12 months, however the liver-somatic index was significantly increased versus controls only at the 12 month time point. RDX had no effect on live-prey capture rates at all time points assayed and no significant impacts on egg production, fertilization or hatch success in the 1-year exposure trial. Genomic analyses indicated that RDX exposure caused limited differential expression of transcripts within time points and no functional conservation of effects indicative of RDX exposure among time points for either brain or liver tissues in the one year exposure. In the multi-generational assay, the effects of acute (96h) exposure to RDX were compared in fish reared to the F2 generation in either control or RDX-exposure conditions. The RDX-reared fish were not observed to have appreciably enhanced RDX tolerance versus the control-reared fish. However, significant differences in gene expression were observed among the control and RDX-reared fish related to neuro-excitatory glutamate metabolism, sensory signaling and processes in neurological development. In total, our results indicate that exposure to an RDX concentration approximating maximum levels observed in the field (0.83 mg/L) caused limited impacts in fathead minnows in a one year exposure, however caused altered expression in genes involved in neural function in a multi-generational exposure. Adult fathead minnows were exposed to 0.83 mg/L (0.15 mg/L standard deviation) in experimental units including 2 male and 4 fish. Five replicate males were randomly sampled with replacement from each of 8 control and 8 RDX-exposed experimental units at 1d, 1mo, 3mo, 6mo, 9mo and 12mo sampling periods. Liver tissue was investigated for differential expression in response to RDX exposure.

Project description:We investigated ecotoxicological effects and toxicogenomic responses in fathead minnows (Pimephales promelas) exposed to an environmentally-relevant concentration (0.83 mg/L) of the munitions compound cyclotrimethylenetrinitramine (RDX) in one year and multi-generational assays. In the one year assay, RDX effects were discerned by comparing breeding groups reared in control or RDX-exposure conditions for one year. RDX had no detectable effect on gonad-somatic index, or condition factor in females assayed at 1 day and at 1, 3, 6, 9, and 12 months, however the liver-somatic index was significantly increased versus controls only at the 12 month time point. RDX had no effect on live-prey capture rates at all time points assayed and no significant impacts on egg production, fertilization or hatch success in the 1-year exposure trial. Genomic analyses indicated that RDX exposure caused limited differential expression of transcripts within time points and no functional conservation of effects indicative of RDX exposure among time points for either brain or liver tissues in the one year exposure. In the multi-generational assay, the effects of acute (96h) exposure to RDX were compared in fish reared to the F2 generation in either control or RDX-exposure conditions. The RDX-reared fish were not observed to have appreciably enhanced RDX tolerance versus the control-reared fish. However, significant differences in gene expression were observed among the control and RDX-reared fish related to neuro-excitatory glutamate metabolism, sensory signaling and processes in neurological development. In total, our results indicate that exposure to an RDX concentration approximating maximum levels observed in the field (0.83 mg/L) caused limited impacts in fathead minnows in a one year exposure, however caused altered expression in genes involved in neural function in a multi-generational exposure. Adult fathead minnows were exposed to 0.83 mg/L (0.15 mg/L standard deviation) in experimental units including 2 male and 4 fish. Five replicate males were randomly sampled with replacement from each of 8 control and 8 RDX-exposed experimental units at 1d, 1mo, 3mo, 6mo, 9mo and 12mo sampling periods. Brain tissue was investigated for differential expression in response to RDX exposure. Data were analyzed in 3 separate investigations. First, the Reference vs Reference data were analysed to determine an empirical false positive detection rate. Next, in order to meet milestones set up by our upper management, we were forced to generate results prior to the end of the bioassay. Therefore, we investigated gene expression among Control and RDX-exposed fish in the 1 day - 6 month sampling periods. Investigation of gene expression among the control and RDX-exposed fish for the 9 month and 12 month time periods were investigated separately.

Project description:Due to difficulties inherent in designating conservation units for effective species management and conservation, the use of multiple complementary sources of information is required to identify and assess the designation of conservation units based on the degree of variation among populations within a species. In this study, we combined estimates of microsatellite and transcriptomic variation to assess the population structure and potential for adaptive variation of threatened Atlantic salmon, Salmo salar, among rivers in the Bay of Fundy. In general, population structure identified by genetic differentiation was consistent with the patterns of variation in gene expression. Both data sets provided clear indication of strong regional differentiation between rivers located within the inner Bay of Fundy relative to rivers located within the outer Bay of Fundy or the Southern Uplands region. There was also support for more refined population structure; there was some differentiation in both microsatellite and gene expression patterns between salmon from rivers in the two regions of the inner Bay of Fundy: Chignecto Bay and Minas Basin. Consistent patterns apparent in the genetic and transcriptomic dataset indicate that Atlantic salmon populations from the inner and outer Bay of Fundy reflect unique genetic lineages, with some evidence of unique genetic legacies between regions of the inner Bay of Fundy, and even between individual rivers within a region. Consistency of the microarray data across two years helps to validate the use of this technique as a useful tool in assessment of variation among wild populations for species conservation. Atlantic salmon samples used in this analysis were collected from Mactaquac and Coldbrook Biodiversity Centres on the east coast of Canada. In year one, eight individuals were hybridized per strain (five strains; 40 individuals in total). This design incorporated dye-swap replicates in which two slides were hybridized with the same pair of individuals, but the dyes were swapped for one of the slides. Therefore, in year one a total of 40 slides were used. Because of the large number of strains assessed in year two (12), dyes were balanced across slides to maximize biological replication. Six individuals were hybridized per strain; three of these were labelled with Cy3, and three were labelled with Cy5 (for a total of 36 arrays in year two).

Dataset Information

Lausannevirus one year microevolution

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