Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    CNVRanger: association analysis of CNVs with gene expression and quantitative phenotypes
    Silva, Vinicius da; Ramos, Marcel ; Groenen, Martien ; Crooijmans, Richard ; Johansson, Anna ; Regitano, Luciana ; Coutinho, Luiz ; Zimmer, Ralf ; Waldron, Levi ; Geistlinger, Ludwig - \ 2020
    Bioinformatics 36 (2020)3. - ISSN 1367-4803 - p. 972 - 973.

    SUMMARY: Copy number variation (CNV) is a major type of structural genomic variation that is increasingly studied across different species for association with diseases and production traits. Established protocols for experimental detection and computational inference of CNVs from SNP array and next-generation sequencing data are available. We present the CNVRanger R/Bioconductor package which implements a comprehensive toolbox for structured downstream analysis of CNVs. This includes functionality for summarizing individual CNV calls across a population, assessing overlap with functional genomic regions, and genome-wide association analysis with gene expression and quantitative phenotypes. AVAILABILITY AND IMPLEMENTATION:

    Toward sustainable environmental quality : Priority research questions for Europe
    Brink, Paul J. Van den; Boxall, Alistair B.A. ; Maltby, Lorraine ; Brooks, Bryan W. ; Rudd, Murray A. ; Backhaus, Thomas ; Spurgeon, David ; Verougstraete, Violaine ; Ajao, Charmaine ; Ankley, Gerald T. ; Apitz, Sabine E. ; Arnold, Kathryn ; Brodin, Tomas ; Cañedo-Argüelles, Miguel ; Chapman, Jennifer ; Corrales, Jone ; Coutellec, Marie Agnès ; Fernandes, Teresa F. ; Fick, Jerker ; Ford, Alex T. ; Giménez Papiol, Gemma ; Groh, Ksenia J. ; Hutchinson, Thomas H. ; Kruger, Hank ; Kukkonen, Jussi V.K. ; Loutseti, Stefania ; Marshall, Stuart ; Muir, Derek ; Ortiz-Santaliestra, Manuel E. ; Paul, Kai B. ; Rico, Andreu ; Rodea-Palomares, Ismael ; Römbke, Jörg ; Rydberg, Tomas ; Segner, Helmut ; Smit, Mathijs ; Gestel, Cornelis A.M. van; Vighi, Marco ; Werner, Inge ; Zimmer, Elke I. ; Wensem, Joke van - \ 2018
    Environmental Toxicology and Chemistry 37 (2018)9. - ISSN 0730-7268 - p. 2281 - 2295.
    Chemical management - Environmental risk assessment - Global megatrends - Key questions exercise - Sustainability

    The United Nations' Sustainable Development Goals have been established to end poverty, protect the planet, and ensure prosperity for all. Delivery of the Sustainable Development Goals will require a healthy and productive environment. An understanding of the impacts of chemicals which can negatively impact environmental health is therefore essential to the delivery of the Sustainable Development Goals. However, current research on and regulation of chemicals in the environment tend to take a simplistic view and do not account for the complexity of the real world, which inhibits the way we manage chemicals. There is therefore an urgent need for a step change in the way we study and communicate the impacts and control of chemicals in the natural environment. To do this requires the major research questions to be identified so that resources are focused on questions that really matter. We present the findings of a horizon-scanning exercise to identify research priorities of the European environmental science community around chemicals in the environment. Using the key questions approach, we identified 22 questions of priority. These questions covered overarching questions about which chemicals we should be most concerned about and where, impacts of global megatrends, protection goals, and sustainability of chemicals; the development and parameterization of assessment and management frameworks; and mechanisms to maximize the impact of the research. The research questions identified provide a first-step in the path forward for the research, regulatory, and business communities to better assess and manage chemicals in the natural environment.

    Priorities for research in soil ecology
    Eisenhauer, Nico ; Antunes, Pedro M. ; Bennett, Alison E. ; Birkhofer, Klaus ; Bissett, Andrew ; Bowker, Matthew A. ; Caruso, Tancredi ; Chen, Baodong ; Coleman, David C. ; Boer, Wietse de; Ruiter, Peter de; DeLuca, Thomas H. ; Frati, Francesco ; Griffiths, Bryan S. ; Hart, Miranda M. ; Hättenschwiler, Stephan ; Haimi, Jari ; Heethoff, Michael ; Kaneko, Nobuhiro ; Kelly, Laura C. ; Leinaas, Hans Petter ; Lindo, Zoë ; Macdonald, Catriona ; Rillig, Matthias C. ; Ruess, Liliane ; Scheu, Stefan ; Schmidt, Olaf ; Seastedt, Timothy R. ; Straalen, Nico M. van; Tiunov, Alexei V. ; Zimmer, Martin ; Powell, Jeff R. - \ 2017
    Pedobiologia 63 (2017). - ISSN 0031-4056 - p. 1 - 7.
    Aboveground-belowground interactions - Biodiversity–ecosystem functioning - Biogeography - Chemical ecology - Climate change - Ecosystem services - Global change - Microbial ecology - Novel environments - Plant-microbe interactions - Soil biodiversity - Soil food web - Soil management - Soil processes
    The ecological interactions that occur in and with soil are of consequence in many ecosystems on the planet. These interactions provide numerous essential ecosystem services, and the sustainable management of soils has attracted increasing scientific and public attention. Although soil ecology emerged as an independent field of research many decades ago, and we have gained important insights into the functioning of soils, there still are fundamental aspects that need to be better understood to ensure that the ecosystem services that soils provide are not lost and that soils can be used in a sustainable way. In this perspectives paper, we highlight some of the major knowledge gaps that should be prioritized in soil ecological research. These research priorities were compiled based on an online survey of 32 editors of Pedobiologia – Journal of Soil Ecology. These editors work at universities and research centers in Europe, North America, Asia, and Australia. The questions were categorized into four themes: (1) soil biodiversity and biogeography, (2) interactions and the functioning of ecosystems, (3) global change and soil management, and (4) new directions. The respondents identified priorities that may be achievable in the near future, as well as several that are currently achievable but remain open. While some of the identified barriers to progress were technological in nature, many respondents cited a need for substantial leadership and goodwill among members of the soil ecology research community, including the need for multi-institutional partnerships, and had substantial concerns regarding the loss of taxonomic expertise.
    Modelling survival: exposure pattern, species sensitivity and uncertainty
    Ashauer, Roman ; Albert, Carlo ; Augustine, Starrlight ; Cedergreen, Nina ; Charles, Sandrine ; Ducrot, Virginie ; Focks, Andreas ; Gabsi, Faten ; Gergs, André ; Goussen, Benoit ; Jager, Tjalling ; Kramer, Nynke I. ; Nyman, Anna-Maija ; Poulsen, Veronique ; Reichenberger, Stefan ; Schäfer, Ralf B. ; Brink, Paul J. Van Den; Veltman, Karin ; Vogel, Sören ; Zimmer, Elke I. ; Preuss, Thomas G. - \ 2016
    Scientific Reports 6 (2016). - ISSN 2045-2322
    The General Unified Threshold model for Survival (GUTS) integrates previously published toxicokinetic-toxicodynamic models and estimates survival with explicitly defined assumptions. Importantly, GUTS accounts for time-variable exposure to the stressor. We performed three studies to test the ability of GUTS to predict survival of aquatic organisms across different pesticide exposure patterns, time scales and species. Firstly, using synthetic data, we identified experimental data requirements which allow for the estimation of all parameters of the GUTS proper model. Secondly, we assessed how well GUTS, calibrated with short-term survival data of Gammarus pulex exposed to four pesticides, can forecast effects of longer-term pulsed exposures. Thirdly, we tested the ability of GUTS to estimate 14-day median effect concentrations of malathion for a range of species and use these estimates to build species sensitivity distributions for different exposure patterns. We find that GUTS adequately predicts survival across exposure patterns that vary over time. When toxicity is assessed for time-variable concentrations species may differ in their responses depending on the exposure profile. This can result in different species sensitivity rankings and safe levels. The interplay of exposure pattern and species sensitivity deserves systematic investigation in order to better understand how organisms respond to stress, including humans.
    Ways of knowing the wastewaterscape : Urban political ecology and the politics of wastewater in Delhi, India
    Karpouzoglou, Timothy ; Zimmer, Anna - \ 2016
    Habitat International (2016). - ISSN 0197-3975 - p. 150 - 160.
    Delhi - India - Knowledge - Urban political ecology - Wastewaterscape

    The notion of waterscape has been proposed by urban political ecology (UPE) scholars as a conceptual lens for understanding urban hydro-social flows. So far, however, there has been little attention by UPE scholars to the importance of wastewater in urban waterscapes. This study demonstrates how wastewater is embedded in an arena of social relations of power, defined in this article as the wastewaterscape. Drawing on research conducted in Delhi, the aim of the study is to examine re-occurring problems of wastewater disposal and mismanagement through the lens of knowledge; and the different ways of knowing about wastewater which exist amongst inhabitants of an informal settlement, scientific experts and municipal workers in Delhi. On the basis of our analysis, we argue that the systemic exposure of poorer urban citizens to untreated wastewater cannot be attributed to the shortcomings of service delivery alone, but is more fundamentally associated with how legitimacy is awarded to competing systems of knowledge about wastewater in the urban sphere.

    Throwing light on behaviour through computer modelling
    Hofstede, Gert Jan - \ 2015
    Evaluation of the sustainability of contrasted pig farming systems : Economy
    Ilari-Antoine, E. ; Bonneau, M. ; Klauke, T.N. ; Gonzàlez, J. ; Dourmad, J.Y. ; Greef, K. De; Houwers, H.W.J. ; Fabrega, E. ; Zimmer, C. ; Hviid, M. ; Oever, B. Van Der; Edwards, S.A. - \ 2014
    Animal 8 (2014)12. - ISSN 1751-7311 - p. 2047 - 2057.
    economy - evaluation - farming system - pig - sustainability

    The aim of this paper is to present an efficient tool for evaluating the economy part of the sustainability of pig farming systems. The selected tool IDEA was tested on a sample of farms from 15 contrasted systems in Europe. A statistical analysis was carried out to check the capacity of the indicators to illustrate the variability of the population and to analyze which of these indicators contributed the most towards it. The scores obtained for the farms were consistent with the reality of pig production; the variable distribution showed an important variability of the sample. The principal component analysis and cluster analysis separated the sample into five subgroups, in which the six main indicators significantly differed, which underlines the robustness of the tool. The IDEA method was proven to be easily comprehensible, requiring few initial variables and with an efficient benchmarking system; all six indicators contributed to fully describe a varied and contrasted population.

    Evaluation of the sustainability of contrasted pig farming systems: The procedure, the evaluated systems and the evaluation tools
    Bonneau, M. ; Greef, K. De; Brinkman, D. ; Cinar, M.U. ; Dourmad, J.Y. ; Edge, H.L. ; Fàbrega, E. ; Gonzàlez, J. ; Houwers, H.W.J. ; Hviid, M. ; Ilari-Antoine, E. ; Klauke, T.N. ; Phatsara, C. ; Rydhmer, L. ; Oever, B. Van Der; Zimmer, C. ; Edwards, S.A. - \ 2014
    Animal 8 (2014)12. - ISSN 1751-7311 - p. 2011 - 2015.
    assessment - farming system - pig - sustainable

    Although a few studies consider the sustainability of animal farming systems along the three classical main pillars (economy, environment and society), most studies on pig farming systems address only one of these pillars. The present paper is the introduction to a series of companion papers presenting the results of a study undertaken within the EU-supported project Q-PorkChains, aiming at building a comprehensive tool for the evaluation of pig farming systems, which is robust to accommodate the large variability of systems existing in Europe. The tool is mostly based on questions to farmers and comprises a total of 37 dimensions distributed along eight themes: Animal Welfare, Animal Health, Breeding Programmes, Environmental Sustainability, Meat Safety, Market Conformity, Economy and Working Conditions. The paper describes the procedure that was used for building the tool, using it on 15 contrasted pig farming systems and analysing the results. The evaluated systems are briefly described and a short overview of the dimensions is provided. Detailed descriptions of the theme-wise tools and results, as well as the results of an integrated evaluation, are available in the companion papers.

    Evaluation of the sustainability of contrasted pig farming systems: development of a market conformity tool for pork products based on technological quality traits
    Gonzalez, J. ; Gispert, M. ; Gil, M. ; Hviid, M. ; Dourmad, J.Y. ; Greef, K.H. de; Zimmer, C. ; Fabrega, E. - \ 2014
    Animal 8 (2014)12. - ISSN 1751-7311 - p. 2038 - 2046.
    meat - ph
    A market conformity tool, based on technological meat quality parameters, was developed within the Q-PorkChains project, to be included in a global sustainability evaluation of pig farming systems. The specific objective of the market conformity tool was to define a scoring system based on the suitability of meat to elaborate the main pork products, according to their market shares based on industry requirements, in different pig farming systems. The tool was based on carcass and meat quality parameters that are commonly used for the assessment of technological quality, which provide representative and repeatable data and are easily measurable. They were the following: cold carcass weight; lean meat percentage; minimum subcutaneous back fat depth at nn. gluteus nnedius level, 45 postmortem and ultimate pH (measured at 24-h postmortem) in m. longissinnus lunnborunn and senninnennbranosus; meat colour; drip losses and intramuscular fat content in a m. longissinnus sample. Five categories of pork products produced at large scale in Europe were considered in the study: fresh meat, cooked products, dry products, specialties and other meat products. For each of the studied farming systems, the technological meat quality requirements, as well as the market shares for each product category within farming system, were obtained from the literature and personal communications from experts. The tool resulted in an overall conformity score that enabled to discriminate among systems according to the degree of matching of the achieved carcass and meat quality with the requirements of the targeted market. In order to improve feasibility, the tool was simplified by selecting ultimate pH at nn. longissinnus or senninnennbranosus, minimum fat thickness measured at the left half carcass over m. gluteus nnedius and intramuscular fat content in a m. longissinnus sample as iceberg indicators. The overall suitability scores calculated by using both the complete and the reduced tools presented good correlation and the results obtained were similar. The tool could be considered as robust enough to discriminate among different systems, since it was tested in a wide range of them. It also can be used to detect improvement opportunities to enhance sustainability of pig farming systems. The final objective of the study was achieved, since the market suitability tool could be used in an integrated sustainability analysis of pig farming systems.
    Evaluation of the sustainability of contrasted pig farming systems: integrated evaluation
    Bonneau, M. ; Klauke, T.N. ; Gonzalez, J. ; Rydhmer, L. ; Ilari-Antoine, E. ; Dourmad, J.Y. ; Greef, K.H. de; Houwers, H.W.J. ; Cinar, M.U. ; Fabrega, E. ; Zimmer, C. ; Hviid, M. ; Oever, B. van der; Edwards, S.A. - \ 2014
    Animal 8 (2014)12. - ISSN 1751-7311 - p. 2058 - 2068.
    management - animals
    The aim of this paper is to present an approach for an integrated evaluation of the sustainability of pig farming systems, taking into account the three classical pillars: economy, environment and society. Eight sustainability themes were considered: Animal Welfare (AW), Animal Health (AH), Breeding Programmes (BP), Environment (EN), Meat Safety (MS), Market Conformity (MC), Economy (EC) and Working Conditions (WC). A total of 37 primary indicators were identified and used for the evaluation of 15 much contrasted pig farming systems in five EU countries. The results show that the eight themes were not redundant and all contributed to the observed variation between systems. The tool was very robust for highlighting the strengths and weaknesses of the systems along the eight themes that were considered. The number of primary indicators could be reduced from 37 to 18 with limited impact on the strengths/weaknesses profile of the individual systems. Integrating the eight theme evaluations into a single sustainability score is based on hypotheses or presumptions on the relative weights that should be given to the eight themes, which are very dependent on the context and on the purpose of the users of the tool. Therefore, the present paper does not have the ambition to provide a ready-for-use tool, rather to suggest an approach for the integrated evaluation of the sustainability of pig farming systems.
    Evaluating environmental impacts of contrasting pig farming systems with life cycle assessment
    Dourmad, J.Y. ; Ryschawy, J. ; Trousson, T. ; Bonneau, M. ; Gonzalez, J. ; Houwers, H.W.J. ; Hviid, M. ; Zimmer, C. ; Nguyen, T.L.T. ; Morgensen, L. - \ 2014
    Animal 8 (2014)12. - ISSN 1751-7311 - p. 2027 - 2037.
    manure production - nh3 - n2o - ch4
    Environmental impacts of 15 European pig farming systems were evaluated in the European Union Q-PorkChains project using life cycle assessment. One conventional and two non-conventional systems were evaluated from each of the five countries: Denmark, The Netherlands, Spain, France and Germany. The data needed for calculations were obtained from surveys of 5 to 10 farms from each system. The systems studied were categorised into conventional (C), adapted conventional (AC), traditional (T) and organic (O). Compared with C systems, AC systems differed little, with only minor changes to improve meat quality, animal welfare or environmental impacts, depending on the system. The difference was much larger for T systems, using very fat, slow-growing traditional breeds and generally outdoor raising of fattening pigs. Environmental impacts were calculated at the farm gate and expressed per kg of pig live weight and per ha of land used. For C systems, impacts per kg LW for climate change, acidification, eutrophication, energy use and land occupation were 2.3 kg CO2-eq, 440g SO2-eq, 18.5g PO4-eq, 16.2 MJ and 41 m(2), respectively. Compared with C, differences in corresponding mean values were +13%, + 5%, 0%, + 2% and +16% higher for AC; +54%, +79%, +23%, +50% and +156% for T, and +4%, -16%, +29%, +11% and +121% for O. Conversely, when expressed per ha of land use, mean impacts were 10% to 60% lower for T and O systems, depending on the impact category. This was mainly because of higher land occupation per kg of pig produced, owing to feed production and the outdoor raising of sows and/or fattening pigs. The use of straw bedding tended to increase climate change impact per kg LW. The use of traditional local breeds, with reduced productivity and feed efficiency, resulted in higher impacts per kg LW for all impact categories. T systems with extensive outdoor raising of pigs resulted in markedly lower impact per ha of land used. Eutrophication potential per ha was substantially lower for 0 systems. Conventional systems had lower global impacts (global warming, energy use, land use), expressed per kg LW, whereas differentiated systems had lower local impacts (eutrophication, acidification), expressed per ha of land use.
    Maarts viooltje schiet al uit grond
    Vliet, Arnold van - \ 2014
    Ook in winter veel steekmuggen
    Vliet, Arnold van - \ 2014
    Putting a Price Tag on Nature’s Defenses
    Zimmer, C. ; Schroter, M. ; Groot, R.S. de; Ploeg, S. van der; Oudenhoven, A.P.E. van; Remme, R.P. ; Opdam, P.F.M. - \ 2014
    New York Times
    The Price Tag on Nature’s Defenses
    Schroter, Matthias ; Groot, Dolf de; Ploeg, Sander van der; Oudenhoven, Alexander van; Remme, Roy ; Opdam, Paul - \ 2014

    Newspaper article in the New York Times featured two papers co-authored by WUR researchers: 'Changes in the global value of ecosystem services' (Global Environmental Change) by R. Costanza, R.S. de Groot, S. van der Ploeg et al. (2014), and 'Ecosystem services as a contested concept: a synthesis of critique and counter-arguments' (Conservation Letters) by M. Schröter, A.P.E. van Oudenhoven, R.P. Remme and R.S. de Groot.

    Tomatoes Blasted with LED Lights Have 50 Percent More Vitamin C
    Zimmer, L. ; Labrie, C.W. ; Wageningen UR Glastuinbouw, - \ 2013
    El Segundo, CA 90245 :
    Policy relevant results from an expert elicitation on the health risks of phthalates
    Zimmer, K.E. ; Gutleb, A.C. ; Ravnum, S. ; Krayer von Krauss, M. ; Murk, A.J. ; Ropstad, E. ; Skaare, J.U. ; Eriksen, G.S. ; Lyche, J.L. ; Koppe, J.G. ; Magnanti, B. ; Yang, A. ; Keune, H. - \ 2012
    Environmental Health : a global access science source 11 (2012)Suppl 1. - ISSN 1476-069X
    Background: The EU 6th Framework Program (FP)-funded Health and Environment Network (HENVINET) aimed to support informed policy making by facilitating the availability of relevant knowledge on different environmental health issues. An approach was developed by which scientific agreement, disagreement, and knowledge gaps could be efficiently identified, and expert advice prepared in a way that is usable for policy makers. There were two aims of the project: 1) to apply the tool to a relevant issue; the potential health impacts of the widely used plasticizers, phthalates, and 2) to evaluate the method and the tool by asking both scientific experts and the target audience, namely policy makers and stakeholders, for their opinions. Methods: The tool consisted of an expert consultation in several steps on the issue of phthalates in environmental health. A diagram depicting the cause-effect chain, from the production and use of phthalates to potential health impacts, was prepared based on existing reviews. This was used as a basis for an online questionnaire, through which experts in the field were consulted. The results of this first round of consultation laid the foundation for a new questionnaire answered by an expert panel that, subsequently, also discussed approaches and results in a workshop. One major task of the expert panel was to pinpoint priorities from the cause-effect chain according to their impact on the extent of potential health risks and their relevance for reducing uncertainty. The results were condensed into a policy brief that was sent to policy makers and stakeholders for their evaluation. Results: The experts agreed about the substantial knowledge gaps within the field of phthalates. The top three priorities for further research and policy action were: 1) intrauterine exposure, 2) reproductive toxicology, and 3) exposure from medical devices. Although not all relevant information from the cause-effect chain is known for phthalates, most experts thought that there are enough indications to justify a precautionary approach and to restrict their general use. Although some of the experts expressed some scepticism about such a tool, most felt that important issues were highlighted. Conclusions: The approach used was an efficient way at summarising priority knowledge gaps as a starting point for health risk assessment of compounds, based on their relevance for the risk assessment outcome. We conclude that this approach is useful for supporting policy makers with state-of-the-art scientific knowledge weighed by experts. The method can assist future evidence-based policy making.
    Policy relevant Results from an Expert Elicitation on the Human Health Risks of Decabromodiphenyl ether (decaBDE) and Hexabromocyclododecane (HBCD)
    Ravnum, S. ; Zimmer, K.E. ; Keune, H. ; Gutleb, A.C. ; Murk, A.J. ; Koppe, J.G. ; Magnanti, B. ; Lyche, J.L. ; Eriksen, G.S. ; Ropstad, E. ; Skaare, J.U. ; Kobernus, M. ; Yang, A. ; Bartonova, A. ; Krayer von Krauss, M. - \ 2012
    Environmental Health : a global access science source 11 (2012)Suppl 1. - ISSN 1476-069X
    brominated flame retardants - polybrominated diphenyl ethers - spontaneous behavior - neonatal exposure - serum - toxicity - trends - pbde - rat - neurotoxicity
    Aim: Apply a recently developed expert elicitation procedure to evaluate the state of the current knowledge of the two brominated flame retardants (BFRs) most commonly used today; decabromo-diphenyl ether (decaBDE) and hexabromocyclododecane (HBCD) and their potential impact on human health in order to support policy considerations. This expert elicitation was organized by the HENVINET (Health and Environment Network) Consortium. Method: The HENVINET expert elicitation procedure that was used in the evaluations of decaBDE and HBCD is a rapid assessment tool aimed at highlighting areas of agreement and areas of disagreement on knowledge-related key issues for environment and health policy decision making. Results: The outcome of the expert consultation on BFRs was concrete expert advice for policy makers with specific priorities for further action made clear for both stakeholders and policy makers. The experts were not in agreement whether or not the knowledge currently available on decaBDE or HBCD is sufficient to justify policy actions, but most experts considered that enough data already exists to support a ban or restriction on the use of these compounds. All experts agreed on the necessity of more research on the compounds. Priority issues for further research were, among others: more studies on the extent of human exposure to the compounds. more studies on the fate and concentration in the human body of the compounds.
    Effects of mixtures of persistent organic pollutants (POPs) derived from cod liver oil on H295R steroidogenesis
    Montano, M. ; Zimmer, K.E. ; Dahl, E. ; Berge, V. ; Olsaker, I. ; Skaare, J.U. ; Murk, A.J. ; Ropstad, E. ; Verhaegen, S. - \ 2011
    Food and Chemical Toxicology 49 (2011)9. - ISSN 0278-6915 - p. 2328 - 2335.
    brominated flame retardants - polybrominated diphenyl ethers - adrenocortical carcinoma-cells - in-vitro - hormone production - gene-expression - aromatic-hydrocarbons - metabolite p,p'-dde - steroid-secretion - pbde metabolites
    Crude cod liver oil and liver oil supplements are consumed as a source of vitamin A, D and polyunsaturated fatty acids; during winter and early pregnancy. Crude cod liver oil however constitutes a considerable source of persistent organic pollutants (POPs). This paper aimed at characterizing and quantifying the influence of POP mixtures extracted from three different steps in the cod liver oil industrial process on hormone production and the expression of steroidogenesis-related genes in H295R cells. Exposure to extracts from crude cod liver oil and from its industrial waste increased progesterone (P4), cortisol (Con), testosterone (T) and estradiol (E2) production; and among others, the expression of MC2R, CYP11B1 and HSD3B2 genes. Observed effects after exposure to pharmaceutical cod liver oil extract were considerably lower. The type of effects on gene expression and hormone production were similar to those induced by forskolin and PCBs, the latter being the major contaminants within the extracts. Additional research is required to further unveil the mechanisms behind the observed steroidogenic effects and to assess whether the potential risk might outweigh the potential benefits of crude and processed cod liver oil consumption.
    In vitro steroidogenic effects of mixtures of persistent organic pollutants (POPs) extracted from burbot (Lota lota) caught in two Norwegian lakes
    Zimmer, K. ; Montano, M. ; Olsaker, I. ; Dahl, E. ; Berg, V. ; Karlsson, C. ; Murk, A.J. ; Skaare, J.U. ; Ropstad, E. ; Verhaegen, S. - \ 2011
    Science of the Total Environment 409 (2011)11. - ISSN 0048-9697 - p. 2040 - 2048.
    endocrine-disrupting chemicals - polybrominated diphenyl ethers - brominated flame retardants - h295r cell-line - polyhalogenated aromatic-hydrocarbons - adrenocortical carcinoma-cells - gene-expression - natural mixtures - transcriptional regulation - aldosterone
    This study investigated the effects of two mixtures of persistent organic pollutants (POPs) on steroidogenesis in the H295R cell line. The two mixtures were obtained from the livers of burbot (Lota lota) caught in two Norwegian lakes (Mjøsa and Losna) with different contaminant profiles. Steroid hormone levels in the cell culture medium and mRNA levels of 16 genes involved in steroidogenesis were investigated. The crude Lake Mjøsa extract had to be diluted ten times more than the Lake Losna extract in order to prevent cytotoxicity. The ten times diluted Lake Mjøsa mixture had higher levels of DDT and derivates (¿DDTs, 1.7 times) and brominated flame retardants (¿BDEs and HBCD, 15-25 times) than the Lake Losna mixture, which, on the other hand, had higher concentrations of ¿PCBs (1.5 times higher) and also of HCB, ¿HCH isomers and ¿chlordane isomers (5-20 times higher). In the cell culture media, only cortisol levels were increased at the highest exposure concentration to the Lake Mjøsa mixture, while both cortisol and estradiol levels were increased following exposure to the two highest Lake Losna mixture exposure concentrations. Testosterone levels decreased only at the highest exposure concentration of the Lake Losna mixture. Multivariate models suggested that ¿PCBs, and to a lesser extent ¿DDTs, were responsible for the cortisol responses, while estradiol and testosterone alterations were best explained by HCB and ¿PCBs, respectively. Exposure to the mixtures generally increased mRNA levels, with smaller effects exerted by the Lake Mjøsa mixture than the Lake Losna mixture. It was concluded that both mixtures affected steroidogenesis in the H295R cells. Small differences in mixture composition, rather than the high content of brominated flame retardants in the Lake Mjøsa mixture, were suggested to be the most probable reason for the apparent differences in potencies of the two mixtures
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