The chemical defensome of five model teleost fish

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Eide, M., Zhang, X., Karlsen, O. A., Goldstone, J., Stegeman, J., Jonassen, I., & Goksoyr, A. The chemical defensome of five model teleost fish. Scientific Reports, 11(1), (2021): 10546, https://doi.org/10.1038/s41598-021-89948-0.How an organism copes with chemicals is largely determined by the genes and proteins that collectively function to defend against, detoxify and eliminate chemical stressors. This integrative network includes receptors and transcription factors, biotransformation enzymes, transporters, antioxidants, and metal- and heat-responsive genes, and is collectively known as the chemical defensome. Teleost fish is the largest group of vertebrate species and can provide valuable insights into the evolution and functional diversity of defensome genes. We have previously shown that the xenosensing pregnane x receptor (pxr, nr1i2) is lost in many teleost species, including Atlantic cod (Gadus morhua) and three-spined stickleback (Gasterosteus aculeatus), but it is not known if compensatory mechanisms or signaling pathways have evolved in its absence. In this study, we compared the genes comprising the chemical defensome of five fish species that span the teleosteii evolutionary branch often used as model species in toxicological studies and environmental monitoring programs: zebrafish (Danio rerio), medaka (Oryzias latipes), Atlantic killifish (Fundulus heteroclitus), Atlantic cod, and three-spined stickleback. Genome mining revealed evolved differences in the number and composition of defensome genes that can have implication for how these species sense and respond to environmental pollutants, but we did not observe any candidates of compensatory mechanisms or pathways in cod and stickleback in the absence of pxr. The results indicate that knowledge regarding the diversity and function of the defensome will be important for toxicological testing and risk assessment studies.The work was supported by the Norwegian Research Council as part of the iCOD and iCOD 2.0 projects (Grant Nos. 192441/I30 and 244654/E40), and the dCod 1.0 project (Grant No. 248840) which is part of Centre for Digital Life Norway. The American collaborators were funded by the National Institute of Health (USA) NIH P42ES007381 (Boston University Superfund Center to JJS and JVG), NIH R21HD073805 (JVG) and NHI R01ES029917 (JVG) grants. The Ocean Outlook exchange program funded the trans-Atlantic collaboration

Conservation and divergence of chemical defense system in the tunicate Oikopleura dioica revealed by genome wide response to two xenobiotics

<p>Abstract</p> <p>Background</p> <p>Animals have developed extensive mechanisms of response to xenobiotic chemical attacks. Although recent genome surveys have suggested a broad conservation of the chemical defensome across metazoans, global gene expression responses to xenobiotics have not been well investigated in most invertebrates. Here, we performed genome survey for key defensome genes in <it>Oikopleura dioica </it>genome, and explored genome-wide gene expression using high density tiling arrays with over 2 million probes, in response to two model xenobiotic chemicals - the carcinogenic polycyclic aromatic hydrocarbon benzo[a]pyrene (BaP) the pharmaceutical compound Clofibrate (Clo).</p> <p>Results</p> <p><it>Oikopleura </it>genome surveys for key genes of the chemical defensome suggested a reduced repertoire. Not more than 23 cytochrome P450 (CYP) genes could be identified, and neither CYP1 family genes nor their transcriptional activator AhR was detected. These two genes were present in deuterostome ancestors. As in vertebrates, the genotoxic compound BaP induced xenobiotic biotransformation and oxidative stress responsive genes. Notable exceptions were genes of the aryl hydrocarbon receptor (AhR) signaling pathway. Clo also affected the expression of many biotransformation genes and markedly repressed genes involved in energy metabolism and muscle contraction pathways.</p> <p>Conclusions</p> <p><it>Oikopleura </it>has the smallest number of CYP genes among sequenced animal genomes and lacks the AhR signaling pathway. However it appears to have basic xenobiotic inducible biotransformation genes such as a conserved genotoxic stress response gene set. Our genome survey and expression study does not support a role of AhR signaling pathway in the chemical defense of metazoans prior to the emergence of vertebrates.</p

Understanding sport clubs as sport policy implementers

The original publication is available at: http://dx.doi.org/10.1080/17430430802196553This article aims at developing a theoretical framework for analysing the implementation of sport policy, as it is conducted by voluntary sport clubs at grass root level. First, three options are presented and discussed: (i) a classical top-down implementation model, (ii) the governance theory of policy tools, and (iii) the Advocacy Coalition Framework. Second, the theoretical perspectives are discussed, and criticized for failing to take sufficiently into account the implementing body of sport policy, namely the voluntary sport clubs. In that respect, an alternative theoretical framework is suggested as a possible solution for analysing the implementation of sport policy; which is the translation perspective of neo-institutionalism. It stresses that, if elements of central policy influence the implementation process at the local level, it does so by the active import, interpretation and implementation of it in the local context. The autonomy of the local sport club in relation to central policy is reinforced by the fact that the activity in sport clubs is mainly done on a voluntary basi

Spawning time in adult polar cod (Boreogadus saida) altered by crude oil exposure, independent of food availability

Fish early life stages are well known for their sensitivity to crude oil exposure. However, the effect of crude oil exposure on adults and their gametes during their spawning period is not well studied. Polar cod, a key arctic fish, may be at risk for crude oil exposure during this potentially sensitive life stage. Additionally, this species experiences lower food availability during their spawning season, with unknown combined consequences. In the present study, wild-caught polar cod were exposed to decreasing levels of a water-soluble fraction (WSF) of crude oil or control conditions and fed either at a low or high feed ration to assess the combined effect of both stressors. Samples were taken during late gonadal development, during active spawning (spawning window), and in the post-spawning period. Histology analysis of gonads from fish sampled during the spawning window showed that oil-exposed polar cod were more likely to have spawned compared to controls. Oil-exposed females had 947 differentially regulated hepatic genes, and their eggs had a higher polycyclic aromatic hydrocarbon body burden compared to controls. Feed ration did not consistently affect polar cod’s response to oil exposure for the endpoints measured, however, did alone result in decreases in some sperm motility parameters. These results suggest that polar cod’s spawning period is a sensitive life event to crude oil exposure, while feed limitation may play a minor role for this supposedly capital breeder. The effects of adult exposure to crude oil on gamete quality and the next generation warrant further investigation

Pharmacokinetics and transcriptional effects of the anti-salmon lice drug emamectin benzoate in Atlantic salmon (Salmo salar L.)

Background Emamectin benzoate (EB) is a dominating pharmaceutical drug used for the treatment and control of infections by sea lice (Lepeophtheirus salmonis) on Atlantic salmon (Salmo salar L). Fish with an initial mean weight of 132 g were experimentally medicated by a standard seven-day EB treatment, and the concentrations of drug in liver, muscle and skin were examined. To investigate how EB affects Atlantic salmon transcription in liver, tissues were assessed by microarray and qPCR at 7, 14 and 35 days after the initiation of medication. Results The pharmacokinetic examination revealed highest EB concentrations in all three tissues at day 14, seven days after the end of the medication period. Only modest effects were seen on the transcriptional levels in liver, with small fold-change alterations in transcription throughout the experimental period. Gene set enrichment analysis (GSEA) indicated that EB treatment induced oxidative stress at day 7 and inflammation at day 14. The qPCR examinations showed that medication by EB significantly increased the transcription of both HSP70 and glutathione-S-transferase (GST) in liver during a period of 35 days, compared to un-treated fish, possibly via activation of enzymes involved in phase II conjugation of metabolism in the liver. Conclusion This study has shown that a standard seven-day EB treatment has only a modest effect on the transcription of genes in liver of Atlantic salmon. Based on GSEA, the medication seems to have produced a temporary oxidative stress response that might have affected protein stability and folding, followed by a secondary inflammatory response.publishedVersio

Biomarkers in Natural Fish Populations Indicate Adverse Biological Effects of Offshore Oil Production

Despite the growing awareness of the necessity of a sustainable development, the global economy continues to depend largely on the consumption of non-renewable energy resources. One such energy resource is fossil oil extracted from the seabed at offshore oil platforms. This type of oil production causes continuous environmental pollution from drilling waste, discharge of large amounts of produced water, and accidental spills.Samples from natural populations of haddock (Melanogrammus aeglefinus) and Atlantic cod (Gadus morhua) in two North Sea areas with extensive oil production were investigated. Exposure to and uptake of polycyclic aromatic hydrocarbons (PAHs) were demonstrated, and biomarker analyses revealed adverse biological effects, including induction of biotransformation enzymes, oxidative stress, altered fatty acid composition, and genotoxicity. Genotoxicity was reflected by a hepatic DNA adduct pattern typical for exposure to a mixture of PAHs. Control material was collected from a North Sea area without oil production and from remote Icelandic waters. The difference between the two control areas indicates significant background pollution in the North Sea.It is most remarkable to obtain biomarker responses in natural fish populations in the open sea that are similar to the biomarker responses in fish from highly polluted areas close to a point source. Risk assessment of various threats to the marine fish populations in the North Sea, such as overfishing, global warming, and eutrophication, should also take into account the ecologically relevant impact of offshore oil production