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Christison BE, Gaidies F, Pineda-Munoz S, Evans AR, Gilbert MA, Fraser D. Dietary niches of creodonts and carnivorans of the late Eocene Cypress Hills Formation. J Mammal 2022; 103:2-17. [PMID: 35087328 PMCID: PMC8789764 DOI: 10.1093/jmammal/gyab123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 10/09/2021] [Indexed: 11/14/2022] Open
Abstract
Modern North American carnivorous mammal assemblages consist of species from a single clade: the Carnivora. Carnivorans once coexisted with members of other meat-eating clades, including the creodonts (Hyaenodontida and Oxyaenida). Creodonts, however, went extinct in North America during the late Eocene and early Oligocene, potentially due to niche overlap and resource competition with contemporary carnivorans. In this study, we employ a community ecology approach to understand whether the dietary niches of coexisting creodonts and carnivorans overlapped during the late Eocene (Chadronian North American Land Mammal Age), a time when creodonts were dwindling and carnivorans were diversifying. We quantify niche overlap based on inferences of diet from carnassial tooth shape estimated using Orientation Patch Count, Dirichlet's Normal Surface Energy, and linear dental measurements as well as from body mass for all species in the Calf Creek Local Fauna of Cypress Hills, Saskatchewan (Treaty 4 land). Although creodonts and carnivorans shared characteristics of their carnassial tooth shape, suggesting similar chewing mechanics and feeding habits, we find that marked differences in body size likely facilitated niche partitioning, at least between the largest creodonts and carnivorans. Calculations of prey focus masses and prey mass spectra indicate that only the smallest creodont may have experienced significant competition for prey with the coeval carnivorans. We suggest that the ultimate extinction of creodonts from North America during the late Eocene and Oligocene was unlikely to have been driven by factors related to niche overlap with carnivorans.
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Affiliation(s)
| | - Fred Gaidies
- Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
| | - Silvia Pineda-Munoz
- Department of Earth and Atmospheric Sciences, Indiana University, Bloomington, IN, USA
- Department of Paleobiology, Smithsonian National Museum of Natural History, Washington, District of Columbia, USA
| | - Alistair R Evans
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
- Geosciences, Museums Victoria, Melbourne, Victoria, Australia
| | - Marisa A Gilbert
- Palaeobiology, Canadian Museum of Nature, Ottawa, Ontario, Canada
| | - Danielle Fraser
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
- Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
- Department of Paleobiology, Smithsonian National Museum of Natural History, Washington, District of Columbia, USA
- Palaeobiology, Canadian Museum of Nature, Ottawa, Ontario, Canada
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2
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Eldridge RJ, de Jourdan BP, Hanson ML. A Critical Review of the Availability, Reliability, and Ecological Relevance of Arctic Species Toxicity Tests for Use in Environmental Risk Assessment. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2022; 41:46-72. [PMID: 34758147 PMCID: PMC9304189 DOI: 10.1002/etc.5247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 10/28/2021] [Accepted: 11/07/2021] [Indexed: 05/26/2023]
Abstract
There is a pressing need to understand the impact of contaminants on Arctic ecosystems; however, most toxicity tests are based on temperate species, and there are issues with reliability and relevance of bioassays in general. Together this may result in an underestimation of harm to Arctic organisms and contribute to significant uncertainty in risk assessments. To help address these concerns, a critical review to assess reported effects for these species, quantify methodological and endpoint relevance gaps, and identify future research needs for testing was performed. We developed uniform criteria to score each study, allowing an objective comparison across experiments to quantify their reliability and relevance. We scored a total of 48 individual studies, capturing 39 tested compounds, 73 unique Arctic test species, and 95 distinct endpoints published from 1975 to 2021. Our analysis shows that of 253 test substance and species combinations scored (i.e., a unique toxicity test), 207 (82%) failed to meet at least one critical study criterion that contributes to data reliability for use in risk assessment. Arctic-focused toxicity testing needs to ensure that exposures can be analytically confirmed, include environmentally realistic exposure scenarios, and report test methods more thoroughly. Significant data gaps were identified as related to standardized toxicity testing with Arctic species, diversity of compounds tested with these organisms, and the inclusion of ecologically relevant sublethal and chronic endpoints assessed in Arctic toxicity testing. Overall, there needs to be ongoing improvement in test conduction and reporting in the scientific literature to support effective risk assessments in an Arctic context. Environ Toxicol Chem 2022;41:46-72. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Affiliation(s)
- Rebecca J. Eldridge
- Huntsman Marine Science CentreSt. AndrewsNew BrunswickCanada
- Department of Environment and GeographyUniversity of ManitobaWinnipegManitobaCanada
| | | | - Mark L. Hanson
- Department of Environment and GeographyUniversity of ManitobaWinnipegManitobaCanada
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3
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Rogstad TW, Sonne C, Villanger GD, Ahlstøm Ø, Fuglei E, Muir DCG, Jørgensen E, Jenssen BM. Concentrations of vitamin A, E, thyroid and testosterone hormones in blood plasma and tissues from emaciated adult male Arctic foxes (Vulpes lagopus) dietary exposed to persistent organic pollutants (POPs). ENVIRONMENTAL RESEARCH 2017; 154:284-290. [PMID: 28119248 DOI: 10.1016/j.envres.2017.01.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/12/2017] [Accepted: 01/13/2017] [Indexed: 06/06/2023]
Abstract
The aim of the present study was to investigate the relationships and effects of oral POP exposure on retinol (vitamin A), α-tocopherol (vitamin E), thyroid hormones and testosterone in emaciated adult farmed Arctic foxes. Eight brother-pairs were exposed to either a diet containing naturally POP-contaminated minke whale blubber (Balaenoptera acutorostrata) (n=8), or a control diet containing pig (Sus scrofa) fat as the primary fat source (n=8) for 22 months. In the whale blubber containing feed the ∑POPs concentration was 802ng/g w.w. and it was 24ng/g w.w. in control feed. The liver mass was significantly higher and the ratio of FT4 (free thyroxine):FT3 (free triiodothyronine) was significantly lower in the POP exposed group as compared to the control group given feed with pig fat (both p<0.05). The exposed group revealed lower plasma and liver concentrations of α-tocopherol compared to the control group (both p<0.05). These results indicate that plasma FT4:FT3 ratio and plasma and liver α-tocopherol are valuable biomarker endpoints for chronic oral POP exposure in wild Arctic foxes. Based on this we suggest that plasma FT4:FT3 ratio and plasma and liver α-tocopherol are valuable biomarker endpoints for chronic POP exposure in wildlife Arctic foxes and that these perturbations may affect their health status.
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Affiliation(s)
- Tonje W Rogstad
- Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Christian Sonne
- Aarhus University, Faculty of Science and Technology, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark.
| | - Gro D Villanger
- Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; Mental and Physical Health, Department of Child Health, Norwegian Institute of Public Health, P.O. Box 4404 Nydalen, 0473 Oslo, Norway
| | - Øystein Ahlstøm
- Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Eva Fuglei
- Norwegian Polar Institute, FRAM Centre, NO-9296 Tromsø, Norway
| | - Derek C G Muir
- National Water Research Institute, Environment Canada, Burlington, Ontario, Canada L7R 4A6
| | - Even Jørgensen
- Department of Arctic and Marine Biology, UiT the Arctic University of Norway, N-9037 Tromsø, Norway
| | - Bjørn Munro Jenssen
- Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
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4
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Dong Y, Tian H, Wang W, Zhang X, Liu J, Ru S. Disruption of the thyroid system by the thyroid-disrupting compound Aroclor 1254 in juvenile Japanese flounder (Paralichthys olivaceus). PLoS One 2014; 9:e104196. [PMID: 25090620 PMCID: PMC4121326 DOI: 10.1371/journal.pone.0104196] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 07/11/2014] [Indexed: 11/30/2022] Open
Abstract
Polychlorinated biphenyls (PCBs) are a group of persistent organochlorine compounds that have the potential to disrupt the homeostasis of thyroid hormones (THs) in fish, particularly juveniles. In this study, thyroid histology, plasma TH levels, and iodothyronine deiodinase (IDs, including ID1, ID2, and ID3) gene expression patterns were examined in juvenile Japanese flounder (Paralichthys olivaceus) following 25- and 50- day waterborne exposure to environmentally relevant concentrations of a commercial PCB mixture, Aroclor 1254 (10, 100, and 1000 ng/L) with two-thirds of the test solutions renewed daily. The results showed that exposure to Aroclor 1254 for 50 d increased follicular cell height, colloid depletion, and hyperplasia. In particular, hypothyroidism, which was induced by the administration of 1000 ng/L Aroclor 1254, significantly decreased plasma TT4, TT3, and FT3 levels. Profiles of the changes in mRNA expression levels of IDs were observed in the liver and kidney after 25 and 50 d PCB exposure, which might be associated with a reduction in plasma THs levels. The expression level of ID2 mRNA in the liver exhibited a dose-dependent increase, indicating that this ID isotype might serve as sensitive and stable indicator for thyroid-disrupting chemical (TDC) exposure. Overall, our study confirmed that environmentally relevant concentrations of Aroclor 1254 cause significant thyroid disruption, with juvenile Japanese flounder being suitable candidates for use in TDC studies.
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Affiliation(s)
- Yifei Dong
- Marine Life Science College, Ocean University of China, Qingdao, Shandong Province, The People's Republic of China
| | - Hua Tian
- Marine Life Science College, Ocean University of China, Qingdao, Shandong Province, The People's Republic of China
| | - Wei Wang
- Marine Life Science College, Ocean University of China, Qingdao, Shandong Province, The People's Republic of China
| | - Xiaona Zhang
- Marine Life Science College, Ocean University of China, Qingdao, Shandong Province, The People's Republic of China
| | - Jinxiang Liu
- Marine Life Science College, Ocean University of China, Qingdao, Shandong Province, The People's Republic of China
| | - Shaoguo Ru
- Marine Life Science College, Ocean University of China, Qingdao, Shandong Province, The People's Republic of China
- * E-mail:
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Simmons DBD, McMaster ME, Reiner EJ, Hewitt LM, Parrott JL, Park BJ, Brown SB, Sherry JP. Wild fish from the Bay of Quinte Area of Concern contain elevated tissue concentrations of PCBs and exhibit evidence of endocrine-related health effects. ENVIRONMENT INTERNATIONAL 2014; 66:124-37. [PMID: 24576942 DOI: 10.1016/j.envint.2014.01.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 01/03/2014] [Accepted: 01/13/2014] [Indexed: 05/27/2023]
Abstract
The Bay of Quinte (BOQ) is an Area of Concern listed under the Great Lakes Water Quality Agreement. The presence of dioxins and dioxin-like PCBs in fish in the BOQ AOC has led to restrictions on fish consumption by humans, which is a beneficial use impairment. Adult yellow perch (Perca flavescens) and brown bullhead (Ameiurus nebulosus) were sampled from Trenton, Belleville, and Deseronto (reference site) in the BOQ. A suite of hormone assays and various measures of exposure and/or sublethal health effects were used to assess the health status of fish of both species and sex. Condition factor, hepatosomatic index, ethoxyresorufin-O-deethylase activity, circulating steroid and thyroid hormones, thyroid activation, oocyte size distribution, spermatogenic cell stages, and plasma vitellogenin were among the endpoints that were significantly (p < 0.05) affected by location. Many of those effects corresponded with significantly (p < 0.05) greater tissue concentrations of polychlorinated biphenyls (PCBs) at Belleville and Trenton. Hepatic extracts from brown bullhead sampled from Trenton had significantly (p < 0.05) greater binding activity to the androgen receptor and sex steroid binding protein. Taken together, these data and preliminary data from a concomitant study suggest that PCBs are likely being hydroxylated in vivo, resulting in enhanced bioactivity at endocrine receptors and measurable health responses. The present study supports the growing body of evidence that PCBs and their metabolites can affect fish thyroid and steroid hormone systems.
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Affiliation(s)
- D B D Simmons
- Aquatic Contaminants Research Division, Environment Canada, National Water Research Institute, Burlington, ON, Canada
| | - M E McMaster
- Aquatic Contaminants Research Division, Environment Canada, National Water Research Institute, Burlington, ON, Canada
| | - E J Reiner
- Laboratory Services Branch, Ontario Ministry of the Environment, Toronto, ON, Canada
| | - L M Hewitt
- Aquatic Contaminants Research Division, Environment Canada, National Water Research Institute, Burlington, ON, Canada
| | - J L Parrott
- Aquatic Contaminants Research Division, Environment Canada, National Water Research Institute, Burlington, ON, Canada
| | - B J Park
- Freshwater Institute, Fisheries and Oceans Canada, Winnipeg, MB, Canada
| | - S B Brown
- Aquatic Contaminants Research Division, Environment Canada, National Water Research Institute, Burlington, ON, Canada
| | - J P Sherry
- Aquatic Contaminants Research Division, Environment Canada, National Water Research Institute, Burlington, ON, Canada
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6
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Arukwe A, Olufsen M, Cicero N, Hansen MD. Effects on development, growth responses and thyroid-hormone systems in eyed-eggs and yolk-sac larvae of Atlantic salmon (Salmo salar) continuously exposed to 3,3',4,4'-tetrachlorobiphenyl (PCB-77). JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2014; 77:574-586. [PMID: 24754393 DOI: 10.1080/15287394.2014.887422] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Thyroid hormones (triiodothyronine, T3; and thyroxine, T4) play significant roles in development, metamorphosis, metabolism, homeostasis, cellular proliferation, and differentiation, for which the effects are mediated through thyroid hormone receptors (TRα and TRβ). Similarly, the insulin-like growth factor (IGF) is involved in growth and development through regulation of somatic growth. This study was designed to examine the effects of the dioxin-like 3,3',4,4'-tetrachlorobiphenyl (PCB-77) on responses related to growth and thyroid hormone system in eyed eggs and yolk-sac larvae of Atlantic salmon. Salmon eggs were continuously exposed to two waterborne concentrations of PCB-77 (1 or 10 ng/L) over a period of 50 d covering hatching and through yolk-sac absorption stages. Sampling was performed regularly throughout the exposure period and at different time intervals. Gene expression patterns were performed on whole-body homogenate at age 500, 548, 632, 674, and 716 dd (dd: day degrees) using quantitative polymerase chain reaction (PCR). Total T3 (TT3) and total T4 (TT4) were measured using radioimmunoassay (RIA). Data showed that 10 ng PCB-77 increased dioiodinase 2 (Dio2) at 500 dd and both PCB-77 concentrations decreased dio2 expression at 548 dd. PCB-77 elevated cellular TT3 at 500 dd and was lowered at 548 dd only at 10 ng. Otherwise, time-related reduction was not affected by PCB-77 exposure as observed for the rest of the exposure period. For TT4, 1 ng PCB-77 produced a rise at 500 dd, and an apparent concentration decrease at 548 dd, before a total inhibition at 632 dd. The IGF-1 and IGF-1R were variably affected by PCB-77. For IGF-2, PCB-77 produced a concentration-dependent increase at 548 dd, and thereafter an elevation (1 ng) and fall (10 ng) at 632 dd. TRβ mRNA demonstrated PCB-77 related increases during the exposure period, and this effect returned to control levels at 716 dd. For TRα, a rise was noted only after exposure to 10 ng PCB-77 at 500 dd. Overall, the present study demonstrates some possible growth and developmental consequences following exposure to PCB-77 during early life stages of Atlantic salmon.
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Affiliation(s)
- Augustine Arukwe
- a Department of Biology , Norwegian University of Science and Technology (NTNU) , Trondheim , Norway
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7
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Xu T, Chen L, Hu C, Zhou B. Effects of acute exposure to polybrominated diphenyl ethers on retinoid signaling in zebrafish larvae. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2013; 35:13-20. [PMID: 23228703 DOI: 10.1016/j.etap.2012.10.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 10/20/2012] [Indexed: 06/01/2023]
Abstract
The objectives of the present study were to investigate the effects of acute exposure to PBDEs on retinoid signaling in fish. Zebrafish embryos (2h post-fertilization, hpf) were exposed to DE-71 (0, 31.0, 68.7, and 227.6μg/L) until 120hpf. Retinoid profiles showed the content of retinal and retinoic acid was reduced significantly. While a significant up-regulation was observed in the transcription of retinal dehydrogenase (raldh2), the transcription of retinol binding protein (rbp1a), retinol dehydrogenase (rdh1), cellular retinoic acid binding protein (crabp1a and crabp2a) and retinoic acid receptor subunit (raraa) were down-regulated significantly, indicating disruption of retinoid signaling. However, the transcriptions of five opsin genes (zfrho, zfuv, zfred, zfblue, and zfgr1) were up-regulated. Furthermore, whole mount immunostaining and western blotting demonstrated increased rhodopsin protein expression in the exposure groups. Overall, the results indicated that acute exposure to PBDEs could disturb retinoid signaling and may impact on eye development of zebrafish larvae.
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Affiliation(s)
- Tao Xu
- Puai Hospital, Huazhong University of Science and Technology, Wuhan 430033, China
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Buckman AH, Fisk AT, Parrott JL, Solomon KR, Brown SB. PCBs can diminish the influence of temperature on thyroid indices in rainbow trout (Oncorhynchus mykiss). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2007; 84:366-378. [PMID: 17681619 DOI: 10.1016/j.aquatox.2007.06.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Revised: 06/25/2007] [Accepted: 06/26/2007] [Indexed: 05/16/2023]
Abstract
The influence of PCBs on the thyroid status of rainbow trout was assessed at various temperatures to identify if PCB mixtures, as well OH-PCBs produced via biotransformation of parent PCBs, can illicit thyroid effects in fish. Juvenile rainbow trout (Oncorhynchus mykiss) held at 8, 12 or 16 degrees C were exposed to dietary concentrations of an environmentally relevant mixture of PCBs for 30 days followed by a depuration phase. Two additional treatments at 12 degrees C included higher concentrations of PCBs (congeners 77, 126 and 169) known to induce CYP1A in fish (referred to as CYP1A treatment) and PCBs (congeners 87, 99, 101, 153, 180, 183 and 194) known to induce CYP2B in mammals (referred to as CYP2 treatment), to assess the influence of more biologically relevant PCB congeners on thyroid indices in fish. Growth rate and liver somatic index varied with water temperature (p<0.05) but did not differ between PCB exposed and control fish (p>0.05) and mortality was low in all treatments. Changes in some measures of thyroid status were apparent in PCB-exposed fish held in the 12 and 16 degrees C treatments while other measures showed no change in any treatment. The natural inverse relationship between thyroid epithelial cell height (TECH) and temperature, was diminished after 30 days of exposure to PCBs as the epithelial cell height in PCB-exposed fish was significantly augmented in the 12 and 16 degrees C treatments compared to controls at these temperatures (p<0.05). However, after 20 days of depuration, TECH values in the PCB exposed fish returned to control values. The natural linear gradient between T(4) outer-ring deiodinase activity (ORD) and temperature was also diminished after 30 days of exposure to PCBs. PCB-exposed fish from the 16 degrees C treatment had significantly lower deiodinase activities (p<0.05) compared to controls at this temperature, but deiodinase activities returned to normal by day 20 of depuration. No differences were observed in T(3) inner-ring deiodinase (IRD) activities and plasma concentrations of T(3) and T(4) in any of the treatments (p>0.05). EROD activity in fish from the CYP1A and CYP2 treatments were elevated compared to control and high dose PCB-exposed treatments (p<0.05), but the inclusion of CYP inducing congeners did not appear to influence any index of thyroid status. Results of this study suggest that exposure of rainbow trout to high concentrations of PCBs and/or OH-PCBs may alter some indices of thyroid status when water temperatures are high, but these changes are within the compensatory scope of the thyroid system based on no change in circulating hormone concentrations, growth rates or mortality.
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Affiliation(s)
- Andrea H Buckman
- Department of Environmental Biology, University of Guelph, Guelph, Ont., Canada N1G 2W1; National Waters Research Institute, Environment Canada, Burlington, Ont., Canada L7R 4A6
| | - Aaron T Fisk
- Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, Windsor, Ont., Canada N9B 3P4.
| | - Joanne L Parrott
- National Waters Research Institute, Environment Canada, Burlington, Ont., Canada L7R 4A6
| | - Keith R Solomon
- Department of Environmental Biology, University of Guelph, Guelph, Ont., Canada N1G 2W1
| | - Scott B Brown
- National Waters Research Institute, Environment Canada, Burlington, Ont., Canada L7R 4A6
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9
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Theodorakis CW, Rinchard J, Carr JA, Park JW, McDaniel L, Liu F, Wages M. Thyroid endocrine disruption in stonerollers and cricket frogs from perchlorate-contaminated streams in east-central Texas. ECOTOXICOLOGY (LONDON, ENGLAND) 2006; 15:31-50. [PMID: 16341611 DOI: 10.1007/s10646-005-0040-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/06/2005] [Indexed: 05/05/2023]
Abstract
In October 2001 and March 2002, a field survey of central stonerollers (Campostoma anomalum) from perchlorate-contaminated streams in central Texas was conducted to assess thyroid endocrine disruption. A survey of adult male and female cricket frogs (Acris crepitans) was performed at the same site between 2001 and 2003. Perchlorate is an oxidizer primarily used in solid-fuel rockets, and many sites that processed or used perchlorate are now contaminated. Histological analysis revealed that the fish from contaminated sites had increased thyroid follicular hyperplasia, hypertrophy, and colloid depletion. Multivariate analysis was generally found to be more powerful than univariate analysis. Seasonal differences existed in the degree of thyroidal perturbation were discovered, and fish were generally less sensitive to thyroidal perturbations in March compared to October. Thyroidal histological indicators were also correlated to levels of perchlorate in the fish, water, and periphyton. Periphyton was frequently most strongly correlated to thyroidal indices, suggesting that exposure through the food chain may be of import. In addition, one of the presumed reference sites turned out to be contaminated with perchlorate, and this was reflected by thyroidal biomarkers before perchlorate was detected in the stream water or biota. There was no evidence of colloid depletion or hyperplasia in frogs from any of the sites, although frogs from two sites with greatest mean water perchlorate concentrations exhibited significantly greater follicle cell hypertrophy. Furthermore, there was a significant positive correlation between follicle cell height and mean water perchlorate concentrations for frogs collected from all sites. This is the first known published account of perchlorate-induced thyroid disruption in fish under field situations, only the second known published account for amphibians, and also points out the value of biomarkers for contaminant biomonitoring.
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Affiliation(s)
- Christopher W Theodorakis
- The Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, PO Box 41163, Lubbock, TX 79409-1163, USA.
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Murvoll KM, Jenssen BM, Skaare JU. Effects of pentabrominated diphenyl ether (PBDE-99) on vitamin status in domestic duck (Anas platyrhynchos) hatchlings. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2005; 68:515-533. [PMID: 15805046 DOI: 10.1080/15287390590909652] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) used to prevent fire are found in several products, such as textiles, electronics, and building materials. They are lipophilic and persistent substances, and their toxicological endpoints resemble those of polychlorinated bipenyls (PCBs). One of the most abundant congeners of PBDEs in wildlife is the 2,2',4,4',5-pentabromodiphenyl ether (PBDE-99). To study the effect of PBDE-99 on vitamin status in birds and evaluate the possible application of vitamins as biomarkers for use in monitoring of wildlife, eggs of domestic duck (Anas platyrhynchos) were exposed by yolk sac injection to environmental realistic doses of this congener (0.1, 1, or 10 ng/g ww). Levels of retinol (vitamin A), retinyl palmitate, and a-tocopherol (vitamin E) were measured in the liver of the newly hatched chicks, and levels of retinol and tocopherol were also measured in plasma. Liver tocopherol levels correlated negatively to the exposure to PBDE-99. This is an indication that exposure to PBDE-99 reduces levels of tocopherol in liver. Thus, tocopherol seems to be a potential useful biomarker for exposure to PBDEs in bird species.
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Affiliation(s)
- Kari Mette Murvoll
- Department of Biology, Norwegian University of Science and Technology, Realfagsbygget, NO-7491 Trondheim, Norway
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11
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Brown SB, Evans RE, Vandenbyllardt L, Finnson KW, Palace VP, Kane AS, Yarechewski AY, Muir DCG. Altered thyroid status in lake trout (Salvelinus namaycush) exposed to co-planar 3,3',4,4',5-pentachlorobiphenyl. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2004; 67:75-85. [PMID: 15019252 DOI: 10.1016/j.aquatox.2003.12.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2003] [Revised: 12/01/2003] [Accepted: 12/03/2003] [Indexed: 05/24/2023]
Abstract
Recent studies indicate that co-planar 3,3',4,4',5-pentachlorobiphenyl (PCB) congeners or their metabolites may disrupt thyroid function in fishes. Although co-planar PCB have been detected at microgram per kilogram levels in fish from contaminated areas, few studies have examined mechanisms whereby, co-planar PCBs may alter thyroid function in fish. We treated immature lake trout by intraperitoneal (i.p.)-injection or dietary gavage with vehicle containing 0, 0.7, 1.2, 25 or 40 microg 3,3',4,4',5-pentachlorobiphenyl (PCB 126) per kgBW. Blood and tissue samples were collected at various times up to 61 weeks following exposure. The treatments produced sustained dose-dependent elevations of tissue (PCB 126) concentrations. Thyroid epithelial cell height (TECH), plasma thyroxine (T4) and 3,3',5-triiodo-l-thyronine (T3) concentrations, hepatic 5'-monodeiodinase, hepatic glucuronidation of T4 and T3, as well as plasma T4 kinetics and fish growth were analyzed. Exposure to the highest doses of PCB 126 caused increased TECH, plasma T4 dynamics and T4-glucuronidation (T4-G). PCB 126 did not affect 5'-monodeiodinase and T3-glucuronidation (T3-G) and there were no effects on fish growth or condition. Because T3 status and growth were unaffected, the thyroid system was able to compensate for the alterations caused by the PCB 126 exposure. It is clear that concentrations of co-planar PCBs similar to those found in predatory fish from contaminated areas in the Great Lakes are capable of enhancing metabolism of T4. These changes may be of significance when T4 requirements are high for other reasons (e.g. periods of rapid growth, warm temperatures, metamorphosis, and parr-smolt transformation).
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Affiliation(s)
- Scott B Brown
- National Water Research Institute, Environment Canada, P.O. Box 5050, Burlington, Ont., Canada L7G 4A6.
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