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Ribeiro YM, Moreira DP, Weber AA, Miranda TGR, Bazzoli N, Rizzo E. Chronic estrone exposure affects spermatogenesis and sperm quality in zebrafish (Danio rerio). ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2023; 98:104058. [PMID: 36596390 DOI: 10.1016/j.etap.2022.104058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 12/21/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
Estrone (E1) is a common environmental contaminant found in rivers and streams due to the farming of animals, such as swine and cattle. Our study evaluated the effects of chronic E1 exposure at environmentally relevant concentrations on spermatogenesis and the semen quality of zebrafish (Danio rerio). We exposed the fish to E1 at concentrations of 20, 200, and 2000 ng/L diluted in 0.001% ethanol (v/v) for 49 days. There were two control groups: one was exposed to water only and the other to ethanol at the same concentration used in the E1 groups. Following exposure, we analyzed the proportion of testicular cell types and other components (%), rate of cell proliferation and death, and sex steroid concentrations. Furthermore, we analyzed the expression of insulin-like growth factor 1 (IGF1), IGF2, IGF1 receptor (IGF1R), and inducible nitric oxide synthase and assessed the semen quality. E1 exposure increased spermatogonia, spermatids, Sertoli cells, Leydig cells, and the proportion of inflammatory infiltrate but decreased the spermatozoa amount. These changes were reflected by reductions in the gonadosomatic index and levels of 11-ketotestosterone in the testes. On the other hand, E1 exposure increased testicular estradiol, IGF1R expression, and nitric oxide production. After an evaluation using a computer-assisted sperm analysis (CASA) system, we observed reduced progressive motility, curvilinear velocity, and beat cross frequency of 20 and 2000 ng/L E1 groups. Our findings support that E1 causes deleterious effects on the testicular function and semen quality of D. rerio even at environmental concentrations. Thus, E1 concentrations should be monitored in surface waters for the purposes of fish conservation.
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Affiliation(s)
- Yves Moreira Ribeiro
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - Davidson Peruci Moreira
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, UFMG, Belo Horizonte, Minas Gerais, Brazil
| | | | | | - Nilo Bazzoli
- Programa de Pós-Graduação em Biologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais, PUC Minas, Belo Horizonte, Minas Gerais, Brazil
| | - Elizete Rizzo
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, UFMG, Belo Horizonte, Minas Gerais, Brazil.
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2
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Orford JT, Ozeki S, Brand JA, Henry J, Wlodkowic D, Alton LA, Martin JM, Wong BBM. Effects of the agricultural pollutant 17β-trenbolone on morphology and behaviour of tadpoles (Limnodynastes tasmaniensis). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2022; 251:106289. [PMID: 36087492 DOI: 10.1016/j.aquatox.2022.106289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 09/01/2022] [Accepted: 09/02/2022] [Indexed: 06/15/2023]
Abstract
Pollutants, such as endocrine disrupting chemicals (EDCs), are increasingly being detected in organisms and ecosystems globally. Agricultural activities, including the use of hormonal growth promotants (HGPs), are a major source of EDC contamination. One potent EDC that enters into the environment through the use of HGPs is 17β-trenbolone. Despite EDCs being repeatedly shown to affect reproduction and development, comparatively little is known regarding their effects on behaviour. Amphibians, one of the most imperilled vertebrate taxa globally, are at particular risk of exposure to such pollutants as they often live and breed near agricultural operations. Yet, no previous research on amphibians has explored the effects of 17β-trenbolone exposure on foraging or antipredator behaviour, both of which are key fitness-related behavioural traits. Accordingly, we investigated the impacts of 28-day exposure to two environmentally realistic concentrations of 17β-trenbolone (average measured concentrations: 10 and 66 ng/L) on the behaviour and growth of spotted marsh frog tadpoles (Limnodynastes tasmaniensis). Contrary to our predictions, there was no significant effect of 17β-trenbolone exposure on tadpole growth, antipredator response, anxiety-like behaviour, or foraging. We hypothesise that the differences in effects found between this study and those conducted on fish may be due to taxonomic differences and/or the life stage of the animals used, and suggest further research is needed to investigate the potential for delayed manifestation of the effects of 17β-trenbolone exposure.
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Affiliation(s)
- Jack T Orford
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia.
| | - Shiho Ozeki
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Jack A Brand
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Jason Henry
- The Neurotoxicology Laboratory, School of Science, RMIT University, Bundoora, VIC, 3083, Australia
| | - Donald Wlodkowic
- The Neurotoxicology Laboratory, School of Science, RMIT University, Bundoora, VIC, 3083, Australia
| | - Lesley A Alton
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Jake M Martin
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia; Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Bob B M Wong
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
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3
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Cooper R, David A, Kudoh T, Tyler CR. Seasonal variation in oestrogenic potency and biological effects of wastewater treatment works effluents assessed using ERE-GFP transgenic zebrafish embryo-larvae. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2021; 237:105864. [PMID: 34118774 DOI: 10.1016/j.aquatox.2021.105864] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 05/06/2021] [Accepted: 05/07/2021] [Indexed: 06/12/2023]
Abstract
Effluents from wastewater treatment works (WwTW) exhibit both temporal and spatial variation in oestrogenicity, however few studies have attempted to quantify how this variation affects biological responses in fish. Here we used an oestrogen-responsive green fluorescent protein (ERE-GFP) transgenic zebrafish (Danio rerio) to quantify oestrogenic activity and health effects for exposure to three different WwTW effluents. Endpoints measured included survival/hatching rate, GFP induction (measured in target tissues or gfp mRNA induction in whole embryos) and vtg mRNA induction in whole embryos. Exposure to one of the study effluents (at 100%), resulted in some mortality, and exposure to all three effluents (at 50% and 100%) caused decreases in hatching rates. Higher levels of vtg mRNA corresponded with higher levels of steroidal oestrogens in the different effluents, with lowest-observed-effect concentrations (LOECs) between 31 ng/L and 39 ng/L oestradiol equivalents (EEQs). Tissue patterns of GFP expression for all three WwTWs effluents reflected the known targets for steroidal oestrogens and for some other oestrogenic chemicals likely present in those effluents (i.e. nonylphenol or bisphenolic compounds). GFP induction was similarly responsive to vtg mRNA induction (a well-established biomarker for oestrogen exposure). We thus demonstrate the ERE-GFP transgenic zebrafish as an effective model for monitoring the oestrogenic potency and health effects for exposure to complex mixtures of chemicals contained within WwTW effluents.
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Affiliation(s)
- Ruth Cooper
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Arthur David
- School of Life Sciences, University of Sussex, Brighton BN1 9QJ, United Kingdom; Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, University of Rennes, F-35000 Rennes, France
| | - Tetsuhiro Kudoh
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Charles R Tyler
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.
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4
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Fetke JK, Martinson JW, Flick RW, Huang W, Bencic DC, See MJ, Pilgrim EM, Debry RW, Biales AD. DNA methylation and expression of estrogen receptor alpha in fathead minnows exposed to 17α-ethynylestradiol. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2021; 233:105788. [PMID: 33662878 PMCID: PMC8317993 DOI: 10.1016/j.aquatox.2021.105788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/15/2021] [Accepted: 02/19/2021] [Indexed: 05/12/2023]
Abstract
The gene expression response thought to underlie the negative apical effects resulting from estrogen exposure have been thoroughly described in fish. Although epigenetics are believed to play a critical role translating environmental exposures into the development of adverse apical effects, they remain poorly characterized in fish species. This study investigated alterations of DNA methylation of estrogen receptor alpha (esr1) in brain and liver tissues from 8 to 10 month old male fathead minnows (Pimephales promelas) after a 2d exposure to either 2.5 ng/L or 10 ng/L 17α-ethynylestradiol (EE2). Changes in the patterns of methylation were evaluated using targeted deep sequencing of bisulfite treated DNA in the 5' region of esr1. Methylation and gene expression were assessed at 2d of exposure and after a 7 and 14d depuration period. After 2d EE2 exposure, males exhibited significant demethylation in the 5' upstream region of esr1 in liver tissue, which was inversely correlated to gene expression. This methylation pattern reflected what was seen in females. No gene body methylation (GBM) was observed for liver of exposed males. Differential methylation was observed for a single upstream CpG site in the liver after the 14d depuration. A less pronounced methylation response was observed in the upstream region in brain tissue, however, several CpGs were necessarily excluded from the analysis. In contrast to the liver, a significant GBM response was observed across the entire gene body, which was sustained until at least 7d post-exposure. No differential expression was observed in the brain, limiting functional interpretation of methylation changes. The identification of EE2-dependent changes in methylation levels strongly suggests the importance of epigenetic mechanisms as a mediator of the organismal response to environmental exposures and the need for further characterization of the epigenome. Further, differential methylation following depuration indicates estrogenic effects persist well after the active exposure, which has implications for the risk posed by repeated exposures..
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Affiliation(s)
- J K Fetke
- Oak Ridge Institute for Science and Education (ORISE) Research Participant at US Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, United States; Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - J W Martinson
- US Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, United States
| | - R W Flick
- US Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, United States
| | - W Huang
- US Environmental Protection Agency, Office of Research and Development, Research Triangle Park, NC, 27709, United States
| | - D C Bencic
- US Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, United States
| | - M J See
- US Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, United States
| | - E M Pilgrim
- US Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, United States
| | - R W Debry
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - A D Biales
- US Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, United States.
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5
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Tinguely SM, David A, Lange A, Tyler CR. Effects of maternal exposure to environmentally relevant concentrations of 17α-ethinyloestradiol in a live bearing freshwater fish, Xenotoca eiseni (Cyprinodontiformes, Goodeidae). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2021; 232:105746. [PMID: 33515925 DOI: 10.1016/j.aquatox.2021.105746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 12/11/2020] [Accepted: 01/10/2021] [Indexed: 06/12/2023]
Abstract
The viviparous teleost Redtail Splitfin (Xenotoca eiseni) is a live bearing fish that presents a novel freshwater model for investigating the effects of maternally derived micropollutants on vulnerable early developmental life stages. Here, adult female X. eiseni were exposed to 17α-ethinyloestradiol (EE2), a potent contraceptive oestrogen, at environmentally relevant concentrations, to investigate for effects on sex partitioning and development. Pregnant and non-pregnant females were exposed for four weeks to EE2 at measured concentrations of 0.9 and 3.4 ng/L EE2 and offspring from gravid females were kept in clean water for a further four weeks. Only pregnant females were seen to respond to 3.4 ng/L EE2 with an increase in the transcription of hepatic vitellogenins (vtgA, vtgB and vtgC). Offspring of exposed mothers showed no obvious effects on somatic growth, gonadal development, sex partitioning or development. However, there was a higher rate of deformities and developmental abnormalities in offspring of EE2-exposed females. The work presented provides the foundation for the development of X. eiseni as a new freshwater model for studies on maternal transfer of chemical pollutants in live bearing animals.
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Affiliation(s)
- Simone M Tinguely
- University of Exeter, Biosciences, College of Life & Environmental Sciences, Exeter EX4 4QD, United Kingdom.
| | - Arthur David
- University of Sussex, School of Life Sciences, Brighton BN1 9QJ, United Kingdom.
| | - Anke Lange
- University of Exeter, Biosciences, College of Life & Environmental Sciences, Exeter EX4 4QD, United Kingdom.
| | - Charles R Tyler
- University of Exeter, Biosciences, College of Life & Environmental Sciences, Exeter EX4 4QD, United Kingdom.
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Hypercrosslinked poly(AN-co-EGDMA-co-VBC): synthesis via suspension polymerization, characterizations, and potential to adsorb diclofenac and metformin from aqueous solution. Colloid Polym Sci 2020. [DOI: 10.1007/s00396-020-04757-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Annunziata L, Visciano P, De Massis MR, Schirone M, Colagrande MN, Campana G, Migliorati G. Detection of ethinyl estradiol and resorcylic acid lactones in poultry meat according to the national residue plan. Drug Test Anal 2020; 13:862-866. [PMID: 33238077 DOI: 10.1002/dta.2984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/17/2020] [Accepted: 11/20/2020] [Indexed: 11/10/2022]
Abstract
The aim of this study was the detection of ethinyl estradiol and resorcylic acid lactones (zeranol and taleranol) in poultry meat samples as unauthorized substances included in the Italian national residue plan. The samples were purified by a solid phase extraction using a C18 column combined with alumina, and the analytes were detected by two specific enzyme-linked immunosorbent assay (ELISA) kits. As they were collected in the frame of official control activities, the method was also validated according to the Commission Decision 2002/657/EC requirements for screening methods with qualitative purpose. Specificity and detection capability were the performance criteria considered for the validation study, and the latter parameter showed a value of 0.5 μg/kg for both the investigated compounds. Such result was well comparable with the data reported by using chromatographic techniques as confirmation methods, and therefore, the ELISA kits tested in this study could be used for the screening of large numbers of samples.
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Affiliation(s)
- Loredana Annunziata
- Bromatologia e Residui, Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise G. Caporale, Teramo, Italy
| | - Pierina Visciano
- Faculty of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, Teramo, Italy
| | - Maria Rosaria De Massis
- Bromatologia e Residui, Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise G. Caporale, Teramo, Italy
| | - Maria Schirone
- Faculty of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, Teramo, Italy
| | - Maria Novella Colagrande
- Bromatologia e Residui, Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise G. Caporale, Teramo, Italy
| | - Guido Campana
- Bromatologia e Residui, Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise G. Caporale, Teramo, Italy
| | - Giacomo Migliorati
- Bromatologia e Residui, Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise G. Caporale, Teramo, Italy
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Jackson L, Klerks P. Effects of the synthetic estrogen 17α-ethinylestradiol on Heterandria formosa populations: Does matrotrophy circumvent population collapse? AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2020; 229:105659. [PMID: 33130452 DOI: 10.1016/j.aquatox.2020.105659] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/05/2020] [Accepted: 10/06/2020] [Indexed: 06/11/2023]
Abstract
Feminization responses have been observed in some wild populations of fish living in rivers and streams, some of which have been shown to arise as a consequence of exposure to sewage treatment (STP) effluent discharges and the endocrine disrupting chemicals (EDCs) they contain which mimic or antagonize the actions of steroid hormones. The synthetic estrogen, 17α-ethinylestradiol (EE2), commonly used in oral contraceptives, is present in surface waters receiving STP effluents at concentrations ranging from non-detectable to 5 ng/L. Despite extensive evidence that EE2 negatively affects the reproductive health of fishes, relatively little is known about effects at the population level - and especially so for live-bearing fishes. To investigate the potential for such impacts, populations of the least killifish (Heterandria formosa) were exposed to 0 or 5 ng/L EE2. Exposures were started with newborn fish and continued for seven months. Chronic exposure to 5 ng/L EE2 caused significant reductions in population size, in abundances of newborns and males, and in population growth rates. The exposure also resulted in a female-biased sex ratio. However, individuals' survival rates were not affected. This study showed that chronic exposure to 5 ng/L EE2 negatively affected population dynamics in a live-bearing fish, demonstrating that the levels of EE2 detected near STPs have the potential to impact wild populations of these fish.
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Affiliation(s)
- Latonya Jackson
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, United States.
| | - Paul Klerks
- Department of Biology, University of Louisiana at Lafayette, Lafayette, LA 70503, United States
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Jiang R, Liu J, Huang B, Wang X, Luan T, Yuan K. Assessment of the potential ecological risk of residual endocrine-disrupting chemicals from wastewater treatment plants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 714:136689. [PMID: 31978772 DOI: 10.1016/j.scitotenv.2020.136689] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 01/08/2020] [Accepted: 01/13/2020] [Indexed: 06/10/2023]
Abstract
Residual chemicals discharged from wastewater treatment plants (WWTPs) and subsequent ecological risk are important in production safety when reuse of the effluent water occurs. Thus, this work provides an investigation of the occurrence and removal of dissolved Endocrine-disrupting chemicals (EDCs) in 38 WWTPs in Guangdong Province, China. The results indicate that EDCs are widely distributed in the investigated WWTPs, while nonylphenols (NPs) are the predominant chemical among the target EDCs, accounting for >98% of the concentration in the influent and >97% of the concentration in the effluent. Moreover, 4 main types of wastewater treatment processes (oxidation ditch, A2/O, conventional activated sludge and microaeration oxidation ditch followed by A2/O) were found to be inefficient for removing dissolved EDCs, with a mean removal rate of approximately 25%. The potential environmental risk was predicted for residual EDCs. Specifically, 17α-ethynylestradiol (EE2) was considered to be the most hazardous chemical among the target EDCs, with a median risk quotient (RQ) of 8.94. In addition, β-estradiol (E2) and estrone (E1) have median RQs of 1.14 and 0.27, and NPs have median RQs of 0.61 (algae), 0.37 (inverberate) and 0.25 (fish), respectively.
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Affiliation(s)
- Ruirun Jiang
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Jiahui Liu
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275, China; State Key Lab of Bioresource and Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China
| | - Bi Huang
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275, China; State Key Lab of Bioresource and Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China
| | - Xiaowei Wang
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Tiangang Luan
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275, China; State Key Lab of Bioresource and Biocontrol, School of Life Science, Sun Yat-sen University, Guangzhou 510275, China; Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Ke Yuan
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275, China.
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Marques da Cunha L, Maitre D, Wedekind C. Low adaptive potential for tolerance to ethynylestradiol, but also low toxicity, in a grayling population (Thymallus thymallus). BMC Evol Biol 2019; 19:227. [PMID: 31842751 PMCID: PMC6916445 DOI: 10.1186/s12862-019-1558-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 12/09/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The presence of a novel pollutant can induce rapid evolution if there is additive genetic variance for the tolerance to the stressor. Continuous selection over some generations can then reduce the toxicity of the pollutant but also deplete the additive genetic variance for the tolerance and thereby slow down adaptation. One common pollutant that has been ecologically relevant for some time is 17alpha-ethynylestradiol (EE2), a synthetic compound of oral contraceptives since their market launch in the 1960s. EE2 is typically found in higher concentrations in rivers than in lakes. Recent experimental work revealed significant genetic variance for the tolerance to EE2 in two lake-spawning salmonid species but no such variance in river-spawning brown trout. We used another river-spawning salmonid, the European grayling Thymallus thymallus, to study the toxicity of an ecologically relevant concentration of EE2. We also used a full-factorial in vitro breeding design and singly rearing of 1555 embryos and larvae of 40 sib groups to test whether there is additive genetic variance for the tolerance to this pollutant. RESULTS We found that exposure to EE2 reduced larval growth after hatching, but contrary to what has been found in the other salmonids, there were no significant effects of EE2 on embryo growth and survival. We found additive genetic variance for embryo viability, i.e. heritability for fitness. However, there was no significant additive variance for the tolerance to EE2. CONCLUSIONS Our findings support the hypothesis that continuous selection has reduced the toxicity of EE2 and depleted genetic variance for tolerance to this synthetic stressor.
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Affiliation(s)
- Lucas Marques da Cunha
- Department of Ecology and Evolution, Biophore, University of Lausanne, 1015, Lausanne, Switzerland
| | - Diane Maitre
- Department of Ecology and Evolution, Biophore, University of Lausanne, 1015, Lausanne, Switzerland
| | - Claus Wedekind
- Department of Ecology and Evolution, Biophore, University of Lausanne, 1015, Lausanne, Switzerland.
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