Project description:Common bottlenose dolphins serve as sentinels for the health of their coastal environments as they are susceptible to health impacts from anthropogenic inputs through both direct exposure and food web magnification. Remote biopsy samples have been widely used to reveal contaminant burdens in free-ranging bottlenose dolphins, but do not address the health consequences of this exposure. To gain insight into whether remote biopsies can also identify health impacts associated with contaminant burdens, we employed RNA sequencing (RNA-seq) to interrogate the transcriptomes of remote skin biopsies from 116 bottlenose dolphins from the northern Gulf of Mexico and southeastern U.S. Atlantic coasts. Gene expression was analyzed using principal component analysis, differential expression testing, and gene co-expression networks, and the results correlated to season, location, and contaminant burden. Season had a significant impact, with over 30% of genes differentially expressed between spring/summer and winter months. Geographic location exhibited lesser effects on the transcriptome, with 15% of genes differentially expressed between the northern Gulf of Mexico and the southeastern U.S. Atlantic locations. Despite a large overlap between the seasonal and geographical gene sets, the pathways altered in the observed gene expression profiles were somewhat distinct. Co-regulated gene modules and differential expression analysis both identified epidermal development and cellular architecture pathways to be expressed at lower levels in animals from the northern Gulf of Mexico. Although contaminant burdens measured were not significantly different between regions, some correlation with contaminant loads in individuals was observed among co-expressed gene modules, but these did not include classical detoxification pathways. Instead, this study identified other, possibly downstream pathways, including those involved in cellular architecture, immune response, and oxidative stress, that may prove to be contaminant responsive markers in bottlenose dolphin skin.
Project description:Concerns have arisen recently over the possible environmental effects of human pharmaceuticals. Although acute toxicities are low, the continuous discharge of pharmaceuticals into the aquatic environment, coupled with the fact that such compounds are selected for use on the basis of a strong pharmacological effect, means that sublethal effects on non-target organisms need to be seriously considered. The juvenile stages of Atlantic salmon are present in many northern European rivers which are also used for the discharge of domestic wastewaters likely to contain pharmaceuticals. One year old salmon parr were exposed to an environmentally relevant concentration (5µg·/ L) of the antidepressant drug carbamazepine for five days and changes of mRNA expression in brain tissues were investigated by means of a custom 17k Atlantic salmon cDNA microarray. The TRAITS 17K Atlantic salmon cDNA microarray was employed. A dual-labelled experimental design was employed for the microarray hybridisations. Each experimental cDNA sample (Cy3 labeled) was competitively hybridised against a common pooled-reference sample (Cy5 labeled). The entire experiment comprised 10 hybridisations - 2 states (CBZ exposed / unexposed) × 1 time-point ( at 5 days) × 5 biological replicates (males only). Hybridisations were undertaken concurrently.
Project description:Aquaculture is one of the fastest growing food production sectors in the world and further expansion is expected throughout the 21st century. However, climate change is threatening the development of the sector and action is needed to prepare the industry for the coming challenges. Using downscaled temperature projections based on the Intergovernmental Panel on Climate Change (IPCC) climate projection (Shared Socioeconomic Pathway, SSP2-4.5), we analysed potential future temperatures at a selected Atlantic cod (Gadus morhua L.) farm site in Northern Norway. Results showed that the farming area may experience increased temperatures the next 10–15 years, including more days with temperatures above 17°C. Based on the predicted future conditions, we designed a study with Atlantic cod (Gadus morhua L.) to evaluate effects from high temperature alone and in combination with Fransicella noatunensis infection. Fish were kept at 12°C and 17°C for eight weeks and samples of skin and spleen collected at different timepoints were analysed with transcriptomics, histology, scanning electron microscopy and immunohistochemistry.