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Mihaich EM, Schäfers C, Dreier DA, Hecker M, Ortego L, Kawashima Y, Dang ZC, Solomon K. Challenges in assigning endocrine-specific modes of action: Recommendations for researchers and regulators. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2017; 13:280-292. [PMID: 27976826 DOI: 10.1002/ieam.1883] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 09/22/2016] [Accepted: 12/01/2016] [Indexed: 06/06/2023]
Abstract
As regulatory programs evaluate substances for their endocrine-disrupting properties, careful study design and data interpretation are needed to distinguish between responses that are truly endocrine specific and those that are not. This is particularly important in regulatory environments where criteria are under development to identify endocrine-disrupting properties to enable hazard-based regulation. Irrespective of these processes, most jurisdictions use the World Health Organization/International Programme on Chemical Safety definition of an endocrine disruptor, requiring that a substance is demonstrated to cause a change in endocrine function that consequently leads to an adverse effect in an intact organism. Such a definition is broad, and at its most cautious might capture many general mechanisms that would not specifically denote an endocrine disruptor. In addition, endocrine responses may be adaptive in nature, designed to maintain homeostasis rather than induce an irreversible adverse effect. The likelihood of indirect effects is increased in (eco)toxicological studies that require the use of maximum tolerated concentrations or doses, which must produce some adverse effect. The misidentification of indirect effects as truly endocrine mediated has serious consequences for prompting animal- and resource-intensive testing and regulatory consequences. To minimize the risk for misidentification, an objective and transparent weight-of-evidence procedure based on biological plausibility, essentiality, and empirical evidence of key events in an adverse outcome pathway is recommended to describe the modes of action that may be involved in toxic responses in nontarget organisms. Confounding factors such as systemic toxicity, general stress, and infection can add complexity to such an evaluation and should be considered in the weight of evidence. A recommended set of questions is proffered to help guide researchers and regulators in discerning endocrine and nonendocrine responses. Although many examples provided in this study are based on ecotoxicology, the majority of the concepts and processes are applicable to both environmental and human health assessments. Integr Environ Assess Manag 2017;13:280-292. © 2016 SETAC.
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Affiliation(s)
- Ellen M Mihaich
- Environmental and Regulatory Resources, Durham, North Carolina, USA
| | | | - David A Dreier
- Center for Environmental & Human Toxicology, Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - Markus Hecker
- School of the Environment & Sustainability and Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Lisa Ortego
- Bayer CropScience, Research Triangle Park, North Carolina, USA
| | | | | | - Keith Solomon
- Centre for Toxicology, School of Environmental Sciences, University of Guelph, Guelph, Ontario, Canada
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Sures B, Nachev M, Selbach C, Marcogliese DJ. Parasite responses to pollution: what we know and where we go in 'Environmental Parasitology'. Parasit Vectors 2017; 10:65. [PMID: 28166838 PMCID: PMC5294906 DOI: 10.1186/s13071-017-2001-3] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 01/24/2017] [Indexed: 01/13/2023] Open
Abstract
Environmental parasitology deals with the interactions between parasites and pollutants in the environment. Their sensitivity to pollutants and environmental disturbances makes many parasite taxa useful indicators of environmental health and anthropogenic impact. Over the last 20 years, three main research directions have been shown to be highly promising and relevant, namely parasites as accumulation indicators for selected pollutants, parasites as effect indicators, and the role of parasites interacting with established bioindicators. The current paper focuses on the potential use of parasites as indicators of environmental pollution and the interactions with their hosts. By reviewing some of the most recent findings in the field of environmental parasitology, we summarize the current state of the art and try to identify promising ideas for future research directions. In detail, we address the suitability of parasites as accumulation indicators and their possible application to demonstrate biological availability of pollutants; the role of parasites as pollutant sinks; the interaction between parasites and biomarkers focusing on combined effects of parasitism and pollution on the health of their hosts; and the use of parasites as indicators of contaminants and ecosystem health. Therefore, this review highlights the application of parasites as indicators at different biological scales, from the organismal to the ecosystem.
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Affiliation(s)
- Bernd Sures
- Aquatic Ecology and Centre for Water and Environmental Research, University of Duisburg-Essen, Universitätsstr. 5, D-45141, Essen, Germany.,Department of Zoology, University of Johannesburg, PO Box 524, Auckland Park 2006, Johannesburg, South Africa
| | - Milen Nachev
- Aquatic Ecology and Centre for Water and Environmental Research, University of Duisburg-Essen, Universitätsstr. 5, D-45141, Essen, Germany.
| | - Christian Selbach
- Water Research Group, Unit for Environmental Sciences and Management, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa
| | - David J Marcogliese
- Aquatic Contaminants Research Division, Water Science and Technology Directorate, Science and Technology Branch, Environment and Climate Change Canada, St. Lawrence Centre, 105 McGill Street, 7th floor, Montreal, QC, H2Y 2E7, Canada.,St. Andrews Biological Station, Fisheries and Oceans Canada, 531 Brandy Cove Road, St, Andrews, NB, E5B 2 L9, Canada
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Sohn WM, Na BK, Jung SG, Kim KH. Mass Death of Predatory Carp, Chanodichthys erythropterus, Induced by Plerocercoid Larvae of Ligula intestinalis (Cestoda: Diphyllobothriidae). THE KOREAN JOURNAL OF PARASITOLOGY 2016; 54:363-8. [PMID: 27417095 PMCID: PMC4977791 DOI: 10.3347/kjp.2016.54.3.363] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 05/10/2016] [Accepted: 05/14/2016] [Indexed: 11/23/2022]
Abstract
We describe here the mass death of predatory carp, Chanodichthys erythropterus, in Korea induced by plerocercoid larvae of Ligula intestinalis as a result of host manipulation. The carcasses of fish with ligulid larvae were first found in the river-edge areas of Chilgok-bo in Nakdong-gang (River), Korea at early February 2016. This ecological phenomena also occurred in the adjacent areas of 3 dams of Nakdong-gang, i.e., Gangjeong-bo, Dalseong-bo, and Hapcheon-Changnyeong-bo. Total 1,173 fish carcasses were collected from the 4 regions. To examine the cause of death, we captured 10 wondering carp in the river-edge areas of Hapcheon-Changnyeong-bo with a landing net. They were 24.0-28.5 cm in length and 147-257 g in weight, and had 2-11 plerocercoid larvae in the abdominal cavity. Their digestive organs were slender and empty, and reproductive organs were not observed at all. The plerocercoid larvae occupied almost all spaces of the abdominal cavity under the air bladders. The proportion of larvae per fish was 14.6-32.1% of body weight. The larvae were ivory-white, 21.5-63.0 cm long, and 6.0-13.8 g in weight. We suggest that the preference for the river-edge in infected fish during winter is a modified behavioral response by host manipulation of the tapeworm larvae. The life cycle of this tapeworm seems to be successfully continued as the infected fish can be easily eaten by avian definitive hosts.
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Affiliation(s)
- Woon-Mok Sohn
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju 52727, Korea
| | - Byoung-Kuk Na
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju 52727, Korea
| | - Soo Gun Jung
- Korea Federation for Environmental Movements in Daegu, Daegu 41259, Korea
| | - Koo Hwan Kim
- Nakdong River Integrated Operations Center, Korea Water Resources Corporation, Busan 49300, Korea
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Kroupova HK, Trubiroha A, Lorenz C, Contardo-Jara V, Lutz I, Grabic R, Kocour M, Kloas W. The progestin levonorgestrel disrupts gonadotropin expression and sex steroid levels in pubertal roach (Rutilus rutilus). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 154:154-162. [PMID: 24893273 DOI: 10.1016/j.aquatox.2014.05.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Revised: 05/07/2014] [Accepted: 05/10/2014] [Indexed: 06/03/2023]
Abstract
The aim of the present study was to investigate the effects of the synthetic progestin levonorgestrel (LNG) on the reproductive endocrine system of a teleost fish, the roach (Rutilus rutilus). Pubertal roach were exposed for 28 days in a flow-through system to four concentrations of LNG (3, 31, 312, and 3124 ng/l). Both males and females treated with 3124 ng/l LNG exhibited the upregulated levels of vitellogenin and oestrogen receptor 1 mRNA in the liver. At the same concentration, LNG caused a significant upregulation of the mRNA expression of the gene encoding luteinising hormone β-subunit (lhβ) and the suppression of the mRNA expression of the gene encoding follicle-stimulating hormone β-subunit (fshβ) in the pituitary of both male and female roach. A lower LNG concentration (312 ng/l) suppressed mRNA expression of fshβ in males only. Females treated with 3124 ng/l LNG exhibited significantly lower plasma 11-ketotestosterone (11-KT) and oestradiol (E2) concentrations, whereas their testosterone (T) level was higher compared with the control. Females exposed to 312 ng/l LNG presented significantly lower plasma E2 concentrations. Males exposed to ≥31 ng/l LNG exhibited significantly reduced 11-KT levels. As determined through a histological analysis, the ovaries of females were not affected by LNG exposure, whereas the testes of males exposed to 31 and 312 ng/l LNG exhibited a significantly higher percentage of spermatogonia B compared with the control. The results of the present study demonstrate that LNG disrupts the reproductive system of pubertal roach by affecting the pituitary gonadotropin expression and the sex steroid levels. This disruption was determined to occur in males after exposure to an environmentally relevant concentration (31 ng/l). Moreover, the highest tested concentration of LNG (3124 ng/l) exerted an oestrogenic effect on fish of both sexes.
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Affiliation(s)
- H K Kroupova
- Research Institute of Fish Culture and Hydrobiology, South Bohemian Research Centre of Aquaculture and Biodiversity of Hydrocenoses, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Zatisi 728/II, CZ-38925 Vodnany, Czech Republic.
| | - A Trubiroha
- Department of Ecophysiology and Aquaculture, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Mueggelseedamm 310, D-12587 Berlin, Germany
| | - C Lorenz
- Department of Ecophysiology and Aquaculture, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Mueggelseedamm 310, D-12587 Berlin, Germany
| | - V Contardo-Jara
- Department of Ecophysiology and Aquaculture, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Mueggelseedamm 310, D-12587 Berlin, Germany; Department Ecological Impact Research and Ecotoxicology, Technische Universität Berlin, Ernst Reuter Platz 1, 10587 Berlin, Germany
| | - I Lutz
- Department of Ecophysiology and Aquaculture, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Mueggelseedamm 310, D-12587 Berlin, Germany
| | - R Grabic
- Research Institute of Fish Culture and Hydrobiology, South Bohemian Research Centre of Aquaculture and Biodiversity of Hydrocenoses, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Zatisi 728/II, CZ-38925 Vodnany, Czech Republic
| | - M Kocour
- Research Institute of Fish Culture and Hydrobiology, South Bohemian Research Centre of Aquaculture and Biodiversity of Hydrocenoses, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Zatisi 728/II, CZ-38925 Vodnany, Czech Republic
| | - W Kloas
- Department of Ecophysiology and Aquaculture, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Mueggelseedamm 310, D-12587 Berlin, Germany; Department of Endocrinology, Humboldt University Berlin, Invalidenstrasse 42, D-10099 Berlin, Germany
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Frank SN, Godehardt S, Nachev M, Trubiroha A, Kloas W, Sures B. Influence of the cestode Ligula intestinalis and the acanthocephalan Polymorphus minutus on levels of heat shock proteins (HSP70) and metallothioneins in their fish and crustacean intermediate hosts. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2013; 180:173-179. [PMID: 23770459 DOI: 10.1016/j.envpol.2013.05.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 04/26/2013] [Accepted: 05/06/2013] [Indexed: 06/02/2023]
Abstract
It is a common method to analyse physiological mechanisms of organisms - commonly referred to as biomarkers - to indicate the presence of environmental pollutants. However, as biomarkers respond to a wide range of stressors we want to direct the attention on natural stressors, i.e. on parasites. After two years maintenance under controlled conditions, roach (Rutilus rutilus) revealed no influence on levels of metallothionein by the parasite Ligula intestinalis. The same was found for Gammarus fossarum infected with Polymorphus minutus. However, the heat shock protein (HSP70) response was affected in both host-parasite systems. While the infection of roach resulted in reduced levels of HSP70 compared to uninfected roach, the infection in G. fossarum led to higher levels of HSP70. We also analysed the effect of a 14 days Cd exposure (4 μg/L) on the uninfected and infected gammarids. The exposure resulted in induced levels for both, metallothionein and HSP70 whereas the combination of stressors, parasite and exposure, revealed a decrease for levels of HSP70 in comparison to the metal exposure only. Accordingly, parasites as natural parts of aquatic ecosystems have to be considered in ecotoxicological research.
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Affiliation(s)
- Sabrina N Frank
- Department of Aquatic Ecology and Centre for Water and Environmental Research (ZWU), University of Duisburg/Essen, Universitätsstrasse 5, D-45141 Essen, Germany
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Kroupova H, Trubiroha A, Wuertz S, Frank SN, Sures B, Kloas W. Nutritional status and gene expression along the somatotropic axis in roach (Rutilus rutilus) infected with the tapeworm Ligula intestinalis. Gen Comp Endocrinol 2012; 177:270-7. [PMID: 22542897 DOI: 10.1016/j.ygcen.2012.04.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 03/16/2012] [Accepted: 04/10/2012] [Indexed: 12/23/2022]
Abstract
The tapeworm Ligula intestinalis inhibits gametogenesis of its fish host, the roach (Rutilus rutilus). We investigated whether L. intestinalis infection makes significant demands on nutritional resources and consequently manipulates the endocrine somatotropic axis of roach. Two groups of naturally infected and uninfected roach were studied: a field group (natural feeding) and a laboratory group (ad libitum food supply). In females, no significant impact of parasitization on storage substrates (glycogen, lipids, and protein) was detected, whereas in males, either lipid content of the liver (field group) or lipid of the muscle and glycogen of the liver (laboratory group) were slightly decreased. Except for the females of the field group, higher mRNA expression of growth hormone (gh) in the pituitary of infected fish was observed. Furthermore, the expression of hypophyseal somatolactin α and β (slα, slβ) was up-regulated in infected females of the field and laboratory group, respectively. In liver and muscle, mRNA expression of insulin-like growth factors (igf1, igf2) and igf receptor (igfr) remained either unchanged or were up-regulated with infection. Parasitization showed inconsistent effects on gh receptor 1 (ghr1) expression in liver and muscle, whereas ghr2 mRNA was mostly not influenced by infection. In general, the expression profile of genes involved in the somatotropic axis as well as the content of storage substances in infected roach did not resemble that of food-deprived fish either under natural or ad libitum feeding. In conclusion, the present study does not indicate starvation of L. intestinalis infected roach, and it is suggested that the inhibition of reproduction attenuated the nutritional demand of parasitization.
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Affiliation(s)
- H Kroupova
- Research Institute of Fish Culture and Hydrobiology, South Bohemian Research Centre of Aquaculture and Biodiversity of Hydrocenoses, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Zatisi 728/II, CZ-38925 Vodnany, Czech Republic.
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Pfennig F, Kurth T, Meißner S, Standke A, Hoppe M, Zieschang F, Reitmayer C, Göbel A, Kretzschmar G, Gutzeit HO. The social status of the male Nile tilapia (Oreochromis niloticus) influences testis structure and gene expression. Reproduction 2012; 143:71-84. [DOI: 10.1530/rep-11-0292] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Dominant and territorial behaviour are known social phenomena in cichlids and social stress influences reproduction and growth. The gonadotropic hormones trigger spermatogenesis and subordinate males have typically lower levels of gonadotropins than dominant males. In this study, we compared testis morphology and gene expression of dominant and subordinate Nile tilapia males (d- and s-males) in socially stable communities. The d-males had the highest gonadosomatic index but they were not the largest animals in the majority of studied cases. Long-term d-males showed large groups of Leydig cells and hyperplasia of the tunica albuginea due to numerous cytochrome-P450-11β-hydroxylase (Cyp11b) expressing myoid cells. Increased Cyp11b expression in d-males was reflected by elevated 11-ketotestosterone plasma values. However, immunofluorescence microscopy and expression analysis of selected genes revealed that most s-males conserved their capability for spermatogenesis and are, therefore, ready for reproduction when the social environment changes. Moreover, in s-males gene expression analysis by quantitative RT-PCR showed increased transcript levels for germ line-specific genes (vasa,sox2anddmc1) and Sertoli-specific genes (amh,amhrIIanddmrt1) whereas gene expression of key factors for steroid production (sf1andcyp11b) were reduced. The Nile tilapia is a promising model to study social cues and gonadotropic signals on testis development in vertebrates.
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Macnab V, Scott AP, Katsiadaki I, Barber I. Variation in the reproductive potential of Schistocephalus infected male sticklebacks is associated with 11-ketotestosterone titre. Horm Behav 2011; 60:371-9. [PMID: 21781969 DOI: 10.1016/j.yhbeh.2011.07.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 07/04/2011] [Accepted: 07/06/2011] [Indexed: 11/19/2022]
Abstract
Parasites can impact host reproduction by interfering with host endocrine systems, but the adaptive nature of such effects is disputed. Schistocephalus solidus plerocercoids are parasites of three-spined sticklebacks Gasterosteus aculeatus that are often associated with impaired host reproduction. Here, we relate reproductive behavior and physiology to levels of the androgen 11-ketotestosterone (11KT) in naturally infected and non-infected male sticklebacks from two UK populations. In one population infected males harbored heavy infections and showed uniformly reduced 11KT titres and kidney spiggin (nesting glue protein) content compared to non-infected fish. However in a second population infection levels were more variable and males with smaller infections recorded 11KT and spiggin titres that overlapped those of non-infected fish; among infected males from this population 11KT and kidney spiggin also both correlated negatively with infection severity. Male reproductive behavior correlated closely with 11KT titre in both populations, and infected males with high 11KT levels exhibited normal reproductive behavior. Our results suggest that Schistocephalus infection per se does not block reproductive development in male sticklebacks, and that some male fish may have the ability to breed whilst infected. Our results are not consistent with the hypothesis that Schistocephalus adaptively castrates male hosts via endocrine disruption; rather they support the hypothesis that reproductive disruption is a side effect of the energetic costs of infection.
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Affiliation(s)
- V Macnab
- Department of Biology, University of Leicester, Leicester LE1 7RH, UK
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Fish hepatic glutathione-S-transferase activity is affected by the cestode parasitesSchistocephalus solidusandLigula intestinalis: evidence from field and laboratory studies. Parasitology 2011; 138:939-44. [DOI: 10.1017/s003118201100045x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
SUMMARYThe activity of hepatic glutathione-S-transferase (GST) was analysed in 3 different fish species with respect to fish sex and infection with parasites. In both sexes of laboratory bred three-spined sticklebacks (Gasterosteus aculeatus)experimentally infected withSchistocephalus solidus(Cestoda), a significantly lower GST-activity was found for infected fish compared to control. After field sampling of roach (Rutilus rutilus) from Lake Müggelsee (MS) and the Reservoir Listertalsperre (LTS), the GST-activity showed significantly lower values for males infected withLigula intestinalisfrom MS (25%) and for infected females from LTS (55%).L. intestinalis-infected female chub (Leuciscus cephalus) from LTS also appeared to have a lower GST-activity. Thus, it could be shown that the presence of parasites significantly affects GST-activity in different fish species resulting in a decreased GST-activity due to infection. Our results therefore emphasize the need for more integrative approaches in environmental pollution research to clearly identify the possible effects of parasites in an effort to develop biomarkers for evaluating environmental health.
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