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Trudeau VL, Thomson P, Zhang WS, Reynaud S, Navarro-Martin L, Langlois VS. Agrochemicals disrupt multiple endocrine axes in amphibians. Mol Cell Endocrinol 2020; 513:110861. [PMID: 32450283 DOI: 10.1016/j.mce.2020.110861] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 04/17/2020] [Accepted: 05/04/2020] [Indexed: 12/20/2022]
Abstract
Concern over global amphibian declines and possible links to agrochemical use has led to research on the endocrine disrupting actions of agrochemicals, such as fertilizers, fungicides, insecticides, acaricides, herbicides, metals, and mixtures. Amphibians, like other species, have to partition resources for body maintenance, growth, and reproduction. Recent studies suggest that metabolic impairments induced by endocrine disrupting chemicals, and more particularly agrichemicals, may disrupt physiological constraints associated with these limited resources and could cause deleterious effects on growth and reproduction. Metabolic disruption has hardly been considered for amphibian species following agrichemical exposure. As for metamorphosis, the key thyroid hormone-dependent developmental phase for amphibians, it can either be advanced or delayed by agrichemicals with consequences for juvenile and adult health and survival. While numerous agrichemicals affect anuran sexual development, including sex reversal and intersex in several species, little is known about the mechanisms involved in dysregulation of the sex differentiation processes. Adult anurans display stereotypical male mating calls and female phonotaxis responses leading to successful amplexus and spawning. These are hormone-dependent behaviours at the foundation of reproductive success. Therefore, male vocalizations are highly ecologically-relevant and may be a non-invasive low-cost method for the assessment of endocrine disruption at the population level. While it is clear that agrochemicals disrupt multiple endocrine systems in frogs, very little has been uncovered regarding the molecular and cellular mechanisms at the basis of these actions. This is surprising, given the importance of the frog models to our deep understanding of developmental biology and thyroid hormone action to understand human health. Several agrochemicals were found to have multiple endocrine effects at once (e.g., targeting both the thyroid and gonadal axes); therefore, the assessment of agrochemicals that alter cross-talk between hormonal systems must be further addressed. Given the diversity of life-history traits in Anura, Caudata, and the Gymnophiona, it is essential that studies on endocrine disruption expand to include the lesser known taxa. Research under ecologically-relevant conditions will also be paramount. Closer collaboration between molecular and cellular endocrinologists and ecotoxicologists and ecologists is thus recommended.
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Affiliation(s)
- Vance L Trudeau
- Department of Biology, University of Ottawa, 30 Marie Curie Private, Ottawa, ON, K1N 6N5, Canada.
| | - Paisley Thomson
- Institut National de la Recherche Scientifique (INRS), Centre Eau Terre Environnement, 490 de la Couronne, Québec (Québec), G1K 9A9, Canada.
| | - Wo Su Zhang
- Department of Biology, University of Ottawa, 30 Marie Curie Private, Ottawa, ON, K1N 6N5, Canada.
| | - Stéphane Reynaud
- Laboratoire d'Ecologie Alpine, UMR UGA-USMB-CNRS 5553, Université Grenoble Alpes, CS 40700, 38058, Grenoble cedex 9, France.
| | - Laia Navarro-Martin
- Institute of Environmental Assessment and Water Research, IDAEA-CSIC, Jordi Girona 18, 08034, Barcelona, Spain.
| | - Valérie S Langlois
- Institut National de la Recherche Scientifique (INRS), Centre Eau Terre Environnement, 490 de la Couronne, Québec (Québec), G1K 9A9, Canada.
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Wu L, Ru H, Ni Z, Zhang X, Xie H, Yao F, Zhang H, Li Y, Zhong L. Comparative thyroid disruption by o,p'-DDT and p,p'-DDE in zebrafish embryos/larvae. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 216:105280. [PMID: 31518776 DOI: 10.1016/j.aquatox.2019.105280] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 08/14/2019] [Accepted: 08/18/2019] [Indexed: 06/10/2023]
Abstract
1,1-Trichloro-2-(p-chlorophenyl)-2-(o-chlorophenyl) ethane (o,p'-DDT) and 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (p,p'-DDE) cause thyroid disruption, but the underlying mechanisms of these disturbances in fish remain unclear. To explore the potential mechanisms of thyroid dysfunction caused by o,p'-DDT and p,p'-DDE, thyroid hormone and gene expression levels in the hypothalamic-pituitary-thyroid (HPT) axis were measured, and the developmental toxicity were recorded in zebrafish larvae. Zebrafish embryos/larvae were exposed to o,p'-DDT (0, 0.28, 2.8, and 28 nM; or 0, 0.1, 1, and 10 μg/L) and p,p'-DDE (0, 1.57, 15.7, and 157 nM; or 0, 0.5, 5, and 50 μg/L) for 7 days. The genes related to thyroid hormone synthesis (crh, tshβ, tg, nis and tpo) and thyroid development (nkx2.1 and pax8) were up-regulated in both the o,p'-DDT and p,p'-DDE exposure groups. Zebrafish embryos/larvae exposed to o,p'-DDT showed significantly increased total whole-body T4 and T3 levels, with the expression of ugt1ab and dio3 being significantly down-regulated. However, the p,p'-DDE exposure groups showed significantly lowered whole-body total T4 and T3 levels, which were associated with up-regulation and down-regulation expression of the expression of dio2 and ugt1ab, respectively. Interestingly, the ratio of T3 to T4 was significantly decreased in the o,p'-DDT (28 nM) and p,p'-DDE (157 nM) exposure groups, suggesting an impairment of thyroid function. In addition, reduced survival rates and body lengths and increased malformation rates were recorded after treatment with either o,p'-DDT or p,p'-DDE. In summary, our study indicates that the disruption of thyroid states was different in response to o,p'-DDT and p,p'-DDE exposure in zebrafish larvae.
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Affiliation(s)
- Luyin Wu
- Observation Station for Fishery Resource and Environment in Upper-Middle Reaches of Yangtze River (Ministry of Agriculture), Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China
| | - Huijun Ru
- Observation Station for Fishery Resource and Environment in Upper-Middle Reaches of Yangtze River (Ministry of Agriculture), Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China
| | - Zhaohui Ni
- Observation Station for Fishery Resource and Environment in Upper-Middle Reaches of Yangtze River (Ministry of Agriculture), Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China
| | - Xiaoxin Zhang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Huaxiao Xie
- Observation Station for Fishery Resource and Environment in Upper-Middle Reaches of Yangtze River (Ministry of Agriculture), Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China
| | - Fan Yao
- Observation Station for Fishery Resource and Environment in Upper-Middle Reaches of Yangtze River (Ministry of Agriculture), Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China; College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - He Zhang
- State Key Laboratory of Optometry, Ophthalmology, and Visual Science, School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325003, China
| | - Yunfeng Li
- Observation Station for Fishery Resource and Environment in Upper-Middle Reaches of Yangtze River (Ministry of Agriculture), Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China.
| | - Liqiao Zhong
- Observation Station for Fishery Resource and Environment in Upper-Middle Reaches of Yangtze River (Ministry of Agriculture), Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China.
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Falfushynska HI, Gnatyshyna LL, Horyn O, Stoliar OB. Vulnerability of marsh frog Pelophylax ridibundus to the typical wastewater effluents ibuprofen, triclosan and estrone, detected by multi-biomarker approach. Comp Biochem Physiol C Toxicol Pharmacol 2017; 202:26-38. [PMID: 28757214 DOI: 10.1016/j.cbpc.2017.07.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 07/23/2017] [Accepted: 07/25/2017] [Indexed: 11/24/2022]
Abstract
Pharmaceutical and personal care products (PPCPs) are the environmental pollutants of growing concern. The aim of this study was to indicate the effects of typical PPCPs on the marsh frog Pelophylax ridibundus. We treated male frogs with waterborne ibuprofen (IBU, 250ng·L-1), triclosan (TCS, 500ng·L-1), or estrone (E1, 100ng·L-1) for 14days. Common vulnerability of the frogs was detected from dramatic decrease of Zn, total and metalated metallothionein (MT) concentrations, Zn/Cu ratio, the elevation of activity of glutathione-S-transferase, cathepsin D and DNA instability in the liver, the depletion of cholinesterase in the brain and cortisol in the blood plasma in all exposures. Nevertheless, lipofuscin concentration in the liver was always decreased. The groups were best distinguished by cytochrome P450 (CYP450) activity determined by ELISA. The exposure to IBU caused lesser damage, but elevated the levels of oxyradicals and glutathione (GSH and GSSG) and lysosomal membrane instability. Exposures to TCS and E1 provoked the endocrine disturbance (increased levels of vitellogenin and thyrotropin in blood plasma), decreased lactate dehydrogenase activity and increased level of pyruvate in the liver. TCS caused the increase of GSSG by 7.3 times and lactate levels. Only E1 lead to decrease of deiodinase activity in the liver, activation of CYP450 and caspase-3 and efflux of cathepsin D from lysosomes. Spectrophotometric and ELISA assays of MTs and CYP450 gave distinct results in E1-group. Broad disruption of the hormonal pathways caused by E1 could be of concern for the health status of frogs in their habitats.
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Affiliation(s)
- Halina I Falfushynska
- Research Laboratory of Comparative Biochemistry and Molecular Biology, Ternopil National Pedagogical University, 2, M. Kryvonosa Str., Ternopil 46027, Ukraine
| | - Lesya L Gnatyshyna
- Research Laboratory of Comparative Biochemistry and Molecular Biology, Ternopil National Pedagogical University, 2, M. Kryvonosa Str., Ternopil 46027, Ukraine; I.Ya. Horbachevsky Ternopil State Medical University, 1, Maidan Voli, Ternopil 46001, Ukraine
| | - Oksana Horyn
- I.Ya. Horbachevsky Ternopil State Medical University, 1, Maidan Voli, Ternopil 46001, Ukraine
| | - Oksana B Stoliar
- Research Laboratory of Comparative Biochemistry and Molecular Biology, Ternopil National Pedagogical University, 2, M. Kryvonosa Str., Ternopil 46027, Ukraine.
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Bulaeva E, Lanctôt C, Reynolds L, Trudeau VL, Navarro-Martín L. Sodium perchlorate disrupts development and affects metamorphosis- and growth-related gene expression in tadpoles of the wood frog (Lithobates sylvaticus). Gen Comp Endocrinol 2015; 222:33-43. [PMID: 25623150 DOI: 10.1016/j.ygcen.2015.01.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 12/19/2014] [Accepted: 01/16/2015] [Indexed: 11/20/2022]
Abstract
Numerous endocrine disrupting chemicals can affect the growth and development of amphibians. We investigated the effects of a targeted disruption of the endocrine axes modulating development and somatic growth. Wood frog (Lithobates sylvaticus) tadpoles were exposed for 2weeks (from developmental Gosner stage (Gs) 25 to Gs30) to sodium perchlorate (SP, thyroid inhibitor, 14mg/L), estradiol (E2, known to alter growth and development, 200nM) and a reduced feeding regime (RF, to affect growth and development in a chemically-independent manner). All treatments experienced developmental delay, and animals exposed to SP or subjected to RF respectively reached metamorphic climax (Gs42) approximately 11(±3) and 17(±3) days later than controls. At Gs42, only SP-treated animals showed increased weight and snout-vent length (P<0.05) relative to controls. Tadpoles treated with SP had 10-times higher levels of liver igf1 mRNA after 4days of exposure (Gs28) compared to controls. Tadpoles in the RF treatment expressed 6-times lower levels of liver igf1 mRNA and 2-times higher liver igf1r mRNA (P<0.05) at Gs30. Tadpoles treated with E2 exhibited similar developmental and growth patterns as controls, but had increased liver igf1 mRNA levels at Gs28, and tail igf1r at Gs42. Effects on tail trβ mRNA levels were detected in SP-treated tadpoles at Gs42, 40days post-exposure, suggesting that the chemical inhibition of thyroid hormone production early in development can have long-lasting effects. The growth effects observed in the SP-exposed animals suggest a relationship between TH-dependent development and somatic growth in L. sylvaticus tadpoles.
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Affiliation(s)
- Elizabeth Bulaeva
- Centre for Advanced Research in Environmental Genomics, Biology Department, University of Ottawa, Ontario K1N 6N5, Canada
| | - Chantal Lanctôt
- Centre for Advanced Research in Environmental Genomics, Biology Department, University of Ottawa, Ontario K1N 6N5, Canada
| | - Leslie Reynolds
- Centre for Advanced Research in Environmental Genomics, Biology Department, University of Ottawa, Ontario K1N 6N5, Canada
| | - Vance L Trudeau
- Centre for Advanced Research in Environmental Genomics, Biology Department, University of Ottawa, Ontario K1N 6N5, Canada
| | - Laia Navarro-Martín
- Centre for Advanced Research in Environmental Genomics, Biology Department, University of Ottawa, Ontario K1N 6N5, Canada.
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Lou Q, Cao S, Xu W, Zhang Y, Qin Z, Wei W. Molecular characterization and mRNA expression of ribosomal protein L8 in Rana nigromaculata during development and under exposure to hormones. J Environ Sci (China) 2014; 26:2331-2339. [PMID: 25458689 DOI: 10.1016/j.jes.2014.09.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 01/22/2014] [Accepted: 02/24/2014] [Indexed: 06/04/2023]
Abstract
Like Xenopus laevis, some species of the Rana genus are also used to study endocrine disrupting chemicals (EDCs). Although ribosomal protein L8 (rpl8) is the most-used reference gene for analyzing gene expression by quantitative reverse transcription polymerase chain reaction in Rana, its suitability as the reference gene has never been validated in any species of the Rana genus. We characterized rpl8 cDNA in Rana nigromaculata, a promising native species in East Asia for assaying endocrine disrupting effects. We found that the rpl8 cDNA consisted of 919bp and encoded 257 amino acids, exhibiting high identities of amino acid sequence with known rpl8 in other Rana species. Then, we examined the stability of mRNA expression during development. Compared with elongation factor 1 alpha 1, another common housekeeping gene, neither stage-specific nor tissue-specific expression of the rpl8 gene was found in all tissues examined (brain, liver, intestine, tail, testis and ovary) during R. nigromaculata development. Finally, we investigated rpl8 expression under exposure to hormones. No change in rpl8 mRNA expression was found under exposure to thyroid hormone (T4) and estrogen (estradiol), whereas expression of the corresponding biomarker genes was induced. Our results show that rpl8 is an appropriate reference gene for analyzing gene expression by quantitative reverse transcription polymerase chain reaction for assaying EDCs using R. nigromaculata, and might also provide support for using rpl8 as a reference gene in other Rana species due to the high conservation of rpl8 among the Rana genus.
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Affiliation(s)
- Qinqin Lou
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Environment, Nanjing University of Technology, Nanjing 210009, China.
| | - Shan Cao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Environment, Nanjing University of Technology, Nanjing 210009, China
| | - Wei Xu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Environment, Nanjing University of Technology, Nanjing 210009, China
| | - Yinfeng Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Zhanfen Qin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Wuji Wei
- College of Environment, Nanjing University of Technology, Nanjing 210009, China
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Navarro-Martín L, Lanctôt C, Jackman P, Park BJ, Doe K, Pauli BD, Trudeau VL. Effects of glyphosate-based herbicides on survival, development, growth and sex ratios of wood frogs (Lithobates sylvaticus) tadpoles. I: chronic laboratory exposures to VisionMax®. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 154:278-90. [PMID: 24878356 DOI: 10.1016/j.aquatox.2014.05.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 05/07/2014] [Accepted: 05/13/2014] [Indexed: 05/06/2023]
Abstract
The purpose of this study was to determine if chronic exposure to the glyphosate-based herbicide VisionMax(®) affects the survival, development, growth, sex ratios and expression of specific genes involved in metamorphosis of wood frog tadpoles (Lithobates sylvaticus). We hypothesized that exposure to this herbicide will affect developmental rates by disrupting hormone pathways, sex ratios and/or gonadal morphology. Tadpoles were chronically exposed in the laboratory from Gosner developmental stage 25 to 42 to four different concentrations of VisionMax(®) (ranging from 0.021 to 2.9 mg acid equivalents/L). Chronic exposures to VisionMax(®) had direct effects on the metamorphosis of L. sylvaticus tadpoles by decreasing development rates, however, there was a decrease in survival only in the group exposed to the highest dose of VisionMax(®) (2.9 mg a.e./L; from approximately 96% in the control group to 77% in the treatment group). There was a decrease in the number of tadpoles reaching metamorphic climax, from 78% in the control group to 42% in the VisionMax(®) (2.9 mg a.e./L) group, and a 7-day delay to reach metamorphic climax in the same treatment group. No effects of exposure on sex ratios or gonadal morphology were detected in tadpoles exposed to any of the concentrations of VisionMax(®) tested. Gene expression analyses in brain and tail tissues demonstrated that exposure to VisionMax(®) alters the expression of key genes involved in development. Results showed significant interaction (two-way ANOVA, P<0.05) between developmental Gosner stage and treatment in brain corticotropin-releasing factor, deiodinase type II (dio2) and glucocorticotiroid receptor (grII) and tail dio2 and grII. This demonstrates that mRNA levels may be differently affected by treatment depending on the developmental stage at which they are assessed. At the same time there was a clear dose-response effect for VisionMax(®) to increase thyroid hormone receptor β in tadpole brain (F(2,69)=3.475, P=0.037) and tail (F(2,69)=27.569, P<0.001), regardless of developmental stage. Interestingly, delays in development (or survival) were only observed in the group exposed to 2.9 mg a.e./L of VisionMax(®), suggesting that tadpoles need to be exposed to a "threshold" concentration of glyphosate-based herbicide to exhibit phenotypic observable effects. We suggest that the upregulation of genes that trigger metamorphosis following VisionMax(®) herbicide exposure might result from a compensatory response for the delays in development observed. Further studies are needed to determine if disruption of expression of these key genes leads to long-term effects when metamorphs reach adult stages.
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Affiliation(s)
- L Navarro-Martín
- Centre for Advanced Research in Environmental Genomics (CAREG), Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
| | - C Lanctôt
- Centre for Advanced Research in Environmental Genomics (CAREG), Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
| | - P Jackman
- Atlantic Laboratory for Environmental Testing, Atlantic Region Environmental Science Centre, Environment Canada, Corner Morton Ave. & University Ave., Moncton, NB E1A 6S8, Canada.
| | - B J Park
- Fisheries and Oceans Canada, Freshwater Institute, Winnipeg, MB R3T 2N6, Canada.
| | - K Doe
- Atlantic Laboratory for Environmental Testing, Atlantic Region Environmental Science Centre, Environment Canada, Corner Morton Ave. & University Ave., Moncton, NB E1A 6S8, Canada.
| | - B D Pauli
- National Wildlife Research Centre, Environment Canada, Carleton University, Raven Road, Ottawa, ON K1A 0H3, Canada.
| | - V L Trudeau
- Centre for Advanced Research in Environmental Genomics (CAREG), Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
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Severtsova EA, Severtsov AS. Crucial stages of embryogenesis of Rana arvalis: Part 2. Development of head structures. Russ J Dev Biol 2012. [DOI: 10.1134/s1062360412030071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Wu JP, Zhang Y, Luo XJ, Chen SJ, Mai BX. DDTs in rice frogs (Rana limnocharis) from an agricultural site, South China: tissue distribution, biomagnification, and potential toxic effects assessment. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2012; 31:705-711. [PMID: 22170703 DOI: 10.1002/etc.1717] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 09/17/2011] [Accepted: 10/28/2011] [Indexed: 05/31/2023]
Abstract
Contamination with agricultural pesticides such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD), is among several proposed stressors contributing to the global declines in amphibian populations and species biodiversity. These chemicals were examined in insects and in the muscle, liver, and eggs of rice frogs (Rana limnocharis) from the paddy fields of an agricultural site in South China. The ΣDDT (sum of DDT, DDE, and DDD) concentrations ranged from 154 to 915, 195 to 1,400, and 165 to 1,930 ng/g lipid weight in the muscle, liver, and eggs, respectively. All the DDTs (DDT, DDE, and DDD) showed higher affinity for the liver relative to muscle tissue and can be maternally transferred to eggs in female frogs. The average biomagnification factors for DDTs ranged from 1.6 to 1.9 and 1.5 to 2.9 in female and male frogs, respectively, providing clear evidence of their biomagnification from insects to frogs. Compared with the reported DDT levels demonstrated to have toxic effects on frogs, DDTs in the present frogs are unlikely to constitute an immediate health risk. However, the adverse impacts of high DDT residues in eggs on the hatching success and their potential toxicity to the newly metamorphosed larval frogs should be assessed further.
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Affiliation(s)
- Jiang-Ping Wu
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
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Carr JA, Patiño R. The hypothalamus-pituitary-thyroid axis in teleosts and amphibians: endocrine disruption and its consequences to natural populations. Gen Comp Endocrinol 2011; 170:299-312. [PMID: 20566362 DOI: 10.1016/j.ygcen.2010.06.001] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Accepted: 06/01/2010] [Indexed: 11/29/2022]
Abstract
Teleosts and pond-breeding amphibians may be exposed to a wide variety of anthropogenic, waterborne contaminants that affect the hypothalamus-pituitary-thyroid (HPT) axis. Because thyroid hormone is required for their normal development and reproduction, the potential impact of HPT-disrupting contaminants on natural teleost and amphibian populations raises special concern. There is laboratory evidence indicating that persistent organic pollutants, heavy metals, pharmaceutical and personal care products, agricultural chemicals, and aerospace products may alter HPT activity, development, and reproduction in teleosts and amphibians. However, at present there is no evidence to clearly link contaminant-induced HPT alterations to impairments in teleost or amphibian population health in the field. Also, with the exception of perchlorate for which laboratory studies have shown a direct link between HPT disruption and adverse impacts on development and reproductive physiology, little is known about if or how other HPT-disrupting contaminants affect organismal performance. Future field studies should focus on establishing temporal associations between the presence of HPT-disrupting chemicals, the occurrence of HPT alterations, and adverse effects on development and reproduction in natural populations; as well as determining how complex mixtures of HPT contaminants affect organismal and population health.
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Affiliation(s)
- James A Carr
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409-3131, USA.
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Mann RM, Hyne RV, Choung CB, Wilson SP. Amphibians and agricultural chemicals: review of the risks in a complex environment. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2009; 157:2903-27. [PMID: 19500891 DOI: 10.1016/j.envpol.2009.05.015] [Citation(s) in RCA: 345] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 05/06/2009] [Accepted: 05/08/2009] [Indexed: 05/18/2023]
Abstract
Agricultural landscapes, although often highly altered in nature, provide habitat for many species of amphibian. However, the persistence and health of amphibian populations are likely to be compromised by the escalating use of pesticides and other agricultural chemicals. This review examines some of the issues relating to exposure of amphibian populations to these chemicals and places emphasis on mechanisms of toxicity. Several mechanisms are highlighted, including those that may disrupt thyroid activity, retinoid pathways, and sexual differentiation. Special emphasis is also placed on the various interactions that may occur between different agro-chemicals and between chemicals and other environmental factors. We also examine the indirect effects on amphibian populations that occur when their surrounding pond communities are altered by chemicals.
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Affiliation(s)
- Reinier M Mann
- Centre for Ecotoxicology, Department of Environmental Sciences, University of Technology - Sydney, NSW, Australia.
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MacKenzie DS, Jones RA, Miller TC. Thyrotropin in teleost fish. Gen Comp Endocrinol 2009; 161:83-9. [PMID: 19135445 DOI: 10.1016/j.ygcen.2008.12.010] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Revised: 12/08/2008] [Accepted: 12/09/2008] [Indexed: 11/22/2022]
Abstract
Thyrotropin (TSH), a pituitary glycoprotein hormone that stimulates the thyroid gland, has been cloned and sequenced from over a dozen teleost fish species. Although TSH is established as a primary driver of systemic thyroid status in mammals, its importance in the regulation of fish thyroid function is still uncertain. We review recent studies indicating that TSH structure is highly conserved across species representing six teleost families. These studies have found TSH messenger RNA consistently expressed in teleost pituitary tissue, although ectopic expression, particularly in gonads, has also been observed. They have also provided evidence for negative feedback inhibition of TSH expression by thyroid hormones, as well as stimulation by hypothalamic peptides. Descriptive studies have found increased TSHbeta expression associated with life history events thought to be promoted by thyroid hormones. These results, coupled with the discovery of a G-protein coupled TSH receptor in several teleost species, supports an active and conserved role for TSH in the regulation of teleost thyroid function. The relative importance of central pathways in regulating thyroid hormone provision to targets and the identity of a proposed thyrotropin-inhibiting factor in teleost fish are still unanswered questions whose resolution will be facilitated by development of methods to measure circulating TSH and its secretion from the pituitary gland.
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Affiliation(s)
- Duncan S MacKenzie
- Dept. of Biology, 3258 TAMU, Texas A&M University, College Station, TX 77843, USA.
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12
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Piña B, Casado M, Quirós L. Analysis of gene expression as a new tool in ecotoxicology and environmental monitoring. Trends Analyt Chem 2007. [DOI: 10.1016/j.trac.2007.09.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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