Project description:The copper redhorse (Moxostoma hubbsi) is an endangered fish endemic to Quebec, Canada that is only known to spawn in two locations within the Richelieu River, a waterway draining a significant area of agricultural land. Accordingly, concerns have been raised over the impacts that agricultural pesticide contamination of spawning grounds and nursery habitats within the Richelieu River may have on early life stage copper redhorse. We assessed the effects of contaminants on early life stages of copper redhorse and river redhorse (Moxostoma carinatum), a closely related fish that shares the copper redhorse’s habitat and spawning grounds but is distributed more widely and is not yet listed as endangered. Copper and river redhorse embryos (1000 each) were exposed to either Richelieu River water in an in-situ flow-through system or to laboratory water used as a control. We assessed embryos hatching time, incidence of deformities and survival in copper and river redhorses. We then performed RNA sequencing on copper redhorse larvae to better understand changes due to river water exposure. We identified 341 compounds in the river water that were absent from lab water. Pesticide concentrations in the river peaked following rainfall during the spawning season. Embryos exposed to river water hatched prematurely at 63.0 and 59.2 cumulative degree days (CDD) compared to 65.4 and 69.9 CDD in laboratory water for river and copper redhorse, respectively. Copper redhorse exposed to river water also had a significantly lower survival rate than laboratory water (73% vs. 93%). RNA sequencing of copper redhorse revealed 18 differentially expressed genes (DEGs) following river water exposure. Eight of the upregulated DEGs (cd44, il1b, lamb3, lamc2, tgm5, orm1, saa, acod1) are linked to immune function and injury response and 7 of the downregulated DEGs (cpa2, ctrb, cela2a, ctrl, cpa1, prss1, cel) are involved with digestion and nutrient absorption. This study provided valuable data on the effects of anthropogenic contaminants present in the Richelieu River and increased our knowledge on the individual and mixture effects they have on an endangered fish.

Project description:Background and Methods: High mercury (Hg) levels are a significant concern in many aquatic environments, and adverse effects of Hg exposure in fish can include altered behavior, reproduction, growth, and increased stress responses. In addition, human health concerns over Hg continue to warrant new research on its mechanisms of action. The objectives of this study were to investigate the impacts of Hg on the female largemouth bass (LMB) central nervous system transcriptome by conducting a laboratory injection experiment with 2.5 M-BM-5g/g body weight in addition to sampling LMB from an environment that contains high levels of Hg (St. MaryM-bM-^@M-^Ys River, Florida, USA). These animals were compared to LMB that inhibit river systems with lower Hg (Big Wekiva, Santa Fe and St. JohnM-bM-^@M-^Ys Rivers Florida, USA). A LMB 8 x 15 K microarray was used for hypothalamic (laboratory) and whole brain (field) transcriptomics analysis. Results: Mercury in the blood of LMB collected from St MaryM-bM-^@M-^Ys River was significantly elevated 3-fold (~ 0.1 ng Hg/ml blood) compared to LMB collected from the other three sites (~ 0.03 ng Hg/ml blood). In the hypothalamus of Hg injected LMB, there were 937 genes that showed differential expression (raw p = 0.05) but there were no probes that passed an FDR for multiple hypothesis correction. In contrast, in field collected LMB there were 2909 genes that that showed differential expression (raw p = 0.05) of which 38 were significant after correction for multiple hypothesis testing (FDR = 0.05). These included Hsp90 co-chaperone Cdc37, multicopper oxidase, mismatch repair protein Msh6, and 16 kDa heat shock protein A. Functional enrichment in whole brains of LMB collected from the field sites revealed that genes involved in the biological processes of protein folding and targeting, regulation of protein metabolic process, and protein degradation (i.e. ubiquitin cycle) were over-represented. Interestingly, gene set enrichment analysis identifed expression targets that were in common between the laboratory experiment (MeHg injected) and field collected LMB and these consisted of mainly homeobox transcription factors (PROP paired-like homeobox 1, LIM homeobox 3 and paired-like homeodomain 1 and 2). Lastly, prevalent themes emerged in the SNEA expression targets that included neuropeptide receptor signaling, steroid signaling, and structural components, such as beta-actin, integrins, and stress fibres. Conclusions: This study characterizes novel cell signaling pathways that underlie Hg toxicity in the teleostean central nervous system. field study with methyl mercury

Project description:Background and Methods: High mercury (Hg) levels are a significant concern in many aquatic environments, and adverse effects of Hg exposure in fish can include altered behavior, reproduction, growth, and increased stress responses. In addition, human health concerns over Hg continue to warrant new research on its mechanisms of action. The objectives of this study were to investigate the impacts of Hg on the female largemouth bass (LMB) central nervous system transcriptome by conducting a laboratory injection experiment with 2.5 M-BM-5g/g body weight in addition to sampling LMB from an environment that contains high levels of Hg (St. MaryM-bM-^@M-^Ys River, Florida, USA). These animals were compared to LMB that inhibit river systems with lower Hg (Big Wekiva, Santa Fe and St. JohnM-bM-^@M-^Ys Rivers Florida, USA). A LMB 8 x 15 K microarray was used for hypothalamic (laboratory) and whole brain (field) transcriptomics analysis. Results: Mercury in the blood of LMB collected from St MaryM-bM-^@M-^Ys River was significantly elevated 3-fold (~ 0.1 ng Hg/ml blood) compared to LMB collected from the other three sites (~ 0.03 ng Hg/ml blood). In the hypothalamus of Hg injected LMB, there were 937 genes that showed differential expression (raw p = 0.05) but there were no probes that passed an FDR for multiple hypothesis correction. In contrast, in field collected LMB there were 2909 genes that that showed differential expression (raw p = 0.05) of which 38 were significant after correction for multiple hypothesis testing (FDR = 0.05). These included Hsp90 co-chaperone Cdc37, multicopper oxidase, mismatch repair protein Msh6, and 16 kDa heat shock protein A. Functional enrichment in whole brains of LMB collected from the field sites revealed that genes involved in the biological processes of protein folding and targeting, regulation of protein metabolic process, and protein degradation (i.e. ubiquitin cycle) were over-represented. Interestingly, gene set enrichment analysis identifed expression targets that were in common between the laboratory experiment (MeHg injected) and field collected LMB and these consisted of mainly homeobox transcription factors (PROP paired-like homeobox 1, LIM homeobox 3 and paired-like homeodomain 1 and 2). Lastly, prevalent themes emerged in the SNEA expression targets that included neuropeptide receptor signaling, steroid signaling, and structural components, such as beta-actin, integrins, and stress fibres. Conclusions: This study characterizes novel cell signaling pathways that underlie Hg toxicity in the teleostean central nervous system. 4 control and 3 treated hypothalami

Project description:Background and Methods: High mercury (Hg) levels are a significant concern in many aquatic environments, and adverse effects of Hg exposure in fish can include altered behavior, reproduction, growth, and increased stress responses. In addition, human health concerns over Hg continue to warrant new research on its mechanisms of action. The objectives of this study were to investigate the impacts of Hg on the female largemouth bass (LMB) central nervous system transcriptome by conducting a laboratory injection experiment with 2.5 µg/g body weight in addition to sampling LMB from an environment that contains high levels of Hg (St. Mary’s River, Florida, USA). These animals were compared to LMB that inhibit river systems with lower Hg (Big Wekiva, Santa Fe and St. John’s Rivers Florida, USA). A LMB 8 x 15 K microarray was used for hypothalamic (laboratory) and whole brain (field) transcriptomics analysis. Results: Mercury in the blood of LMB collected from St Mary’s River was significantly elevated 3-fold (~ 0.1 ng Hg/ml blood) compared to LMB collected from the other three sites (~ 0.03 ng Hg/ml blood). In the hypothalamus of Hg injected LMB, there were 937 genes that showed differential expression (raw p = 0.05) but there were no probes that passed an FDR for multiple hypothesis correction. In contrast, in field collected LMB there were 2909 genes that that showed differential expression (raw p = 0.05) of which 38 were significant after correction for multiple hypothesis testing (FDR = 0.05). These included Hsp90 co-chaperone Cdc37, multicopper oxidase, mismatch repair protein Msh6, and 16 kDa heat shock protein A. Functional enrichment in whole brains of LMB collected from the field sites revealed that genes involved in the biological processes of protein folding and targeting, regulation of protein metabolic process, and protein degradation (i.e. ubiquitin cycle) were over-represented. Interestingly, gene set enrichment analysis identifed expression targets that were in common between the laboratory experiment (MeHg injected) and field collected LMB and these consisted of mainly homeobox transcription factors (PROP paired-like homeobox 1, LIM homeobox 3 and paired-like homeodomain 1 and 2). Lastly, prevalent themes emerged in the SNEA expression targets that included neuropeptide receptor signaling, steroid signaling, and structural components, such as beta-actin, integrins, and stress fibres. Conclusions: This study characterizes novel cell signaling pathways that underlie Hg toxicity in the teleostean central nervous system.

			Action	DRS
	SRR30633000_1.fastq.gz	Fastqsanger.gz
	SRR30633000_2.fastq.gz	Fastqsanger.gz
	SRR30635200_1.fastq.gz	Fastqsanger.gz
	SRR30635200_2.fastq.gz	Fastqsanger.gz
	SRR30635300_1.fastq.gz	Fastqsanger.gz

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