Global transcriptome profiling reveals molecular mechanisms of metal tolerance in a chronically exposed wild population of brown trout.

addresses: Biosciences, College of Life & Environmental Sciences, Geoffrey Pope Building, University of Exeter , Exeter, EX4 4QD. [email protected] © 2013 American Chemical SocietyThis is an open access article that is freely available in ORE or from the publisher's web site. http://pubs.acs.org/doi/abs/10.1021/es401380p Please cite the published versioncontacts: T.M.U.W.: E-mail [email protected], phone +44 (0)1392 724677, fax +44 (0)1392 263434. E.M.S.: E-mail E.Santos@ exeter.ac.uk, phone +44 (0)1392 264607, fax +44 (0)1392 263434.Worldwide, a number of viable populations of fish are found in environments heavily contaminated with metals, including brown trout (Salmo trutta) inhabiting the River Hayle in South-West of England. This population is chronically exposed to a water-borne mixture of metals, including copper and zinc, at concentrations lethal to naïve fish. We aimed to investigate the molecular mechanisms employed by the River Hayle brown trout to tolerate high metal concentrations. To achieve this, we combined tissue metal analysis with whole-transcriptome profiling using RNA-seq on an Illumina platform. Metal concentrations in the Hayle trout, compared to fish from a relatively unimpacted river, were significantly increased in the gills, liver and kidney (63-, 34- and 19-fold respectively), but not the gut. This confirms that these fish can tolerate considerable metal accumulation, highlighting the importance of these tissues in metal uptake (gill), storage and detoxification (liver, kidney). We sequenced, assembled and annotated the brown trout transcriptome using a de novo approach. Subsequent gene expression analysis identified 998 differentially expressed transcripts and functional analysis revealed that metal- and ion-homeostasis pathways are likely to be the most important mechanisms contributing to the metal tolerance exhibited by this population.Natural Environment Research Council (NERC

Investigation into Adaptation in Genes Associated with Response to Estrogenic Pollution in Populations of Roach (Rutilus rutilus) Living in English Rivers

UK Natural Environmental Research Council (NERC; NE/K004263/1); NERC Biomolecular Analysis Facility for funding (NBAF866); Medical Research Council Clinical Infrastructure award (MR/M008924/1); Wellcome Trust Institutional Strategic Support Fund (WT097835MF); Wellcome Trust Multi User Equipment Award (WT101650MA); BBSRC LOLA award (BB/ K003240/1)

Global transcriptomic profiling demonstrates induction of oxidative stress and of compensatory cellular stress responses in brown trout exposed to glyphosate and Roundup

notes: PMCID: PMC4318436Copyright © 2015 Uren Webster and Santos; licensee BioMed Central.BackgroundGlyphosate, the active ingredient in Roundup formulations, is the most widely used herbicide worldwide, and as a result contaminates surface waters and has been detected in food residues, drinking water and human urine, raising concerns for potential environmental and human health impacts. Research has shown that glyphosate and Roundup can induce a broad range of biological effects in exposed organisms, particularly via generation of oxidative stress. However, there has been no comprehensive investigation of the global molecular mechanisms of toxicity of glyphosate and Roundup for any species. We aimed to characterise and compare the global mechanisms of toxicity of glyphosate and Roundup in the liver of brown trout (Salmo trutta), an ecologically and economically important vertebrate species, using RNA-seq on an Illumina HiSeq 2500 platform. To do this, we exposed juvenile female brown trout to 0, 0.01, 0.5 and 10 mg/L of glyphosate and Roundup (glyphosate acid equivalent) for 14 days, and sequenced 6 replicate liver samples from each treatment.ResultsWe assembled the brown trout transcriptome using an optimised de novo approach, and subsequent differential expression analysis identified a total of 1020 differentially-regulated transcripts across all treatments. These included transcripts encoding components of the antioxidant system, a number of stress-response proteins and pro-apoptotic signalling molecules. Functional analysis also revealed over-representation of pathways involved in regulating of cell-proliferation and turnover, and up-regulation of energy metabolism and other metabolic processes.ConclusionsThese transcriptional changes are consistent with generation of oxidative stress and the widespread induction of compensatory cellular stress response pathways. The mechanisms of toxicity identified were similar across both glyphosate and Roundup treatments, including for environmentally relevant concentrations. The significant alterations in transcript expression observed at the lowest concentrations tested raises concerns for the potential toxicity of this herbicide to fish populations inhabiting contaminated rivers.NERCSalmon & Trout AssociationWellcome Trust Institutional Strategic Support Awar