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Svanholm S, Roza M, Marini D, Brouard V, Karlsson O, Berg C. Pubertal sexual development and endpoints for disrupted spermatogenesis in the model Xenopus tropicalis. Reprod Toxicol 2023; 120:108435. [PMID: 37400040 DOI: 10.1016/j.reprotox.2023.108435] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 06/27/2023] [Accepted: 06/30/2023] [Indexed: 07/05/2023]
Abstract
Peripubertal models to determine effects of anti-androgenic endocrine disrupting chemicals are needed. Using the toxicological model species Xenopus tropicalis, the aims of the study were to 1) provide data on sexual maturation and 2) characterise effects of short-term exposure to an anti-androgenic model substance. Juvenile (2.5 weeks post metamorphosis old) X. tropicalis were exposed to 0, 250, 500 or 1000 µg flutamide/L (nominal) for 2.5 weeks. Upon exposure termination, histology of gonads and Müllerian ducts was characterised in detail. New sperm stages were identified: pale and dark spermatogonial stem cells (SSCs). The testes of control males contained spermatozoa, indicating pubertal onset. The ovaries were immature, and composed of non-follicular and pre-vitellogenic follicular oocytes. The Müllerian ducts were more mature in females than males indicating development/regression in the females and males, respectively. In the 500 µg/L group, the number of dark SSCs per testis area was decreased and the number of secondary spermatogonia was increased. No treatment effects on ovaries or Müllerian ducts were detected. To conclude, our present data provide new knowledge on spermatogenesis, and pubertal onset in X. tropicalis. New endpoints for evaluating spermatogenesis are suggested to be added to existing assays used in endocrine and reproductive toxicology.
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Affiliation(s)
- Sofie Svanholm
- Department of Environmental Toxicology, Uppsala University, Uppsala 754 36, Sweden.
| | - Mauricio Roza
- Science for Life Laboratory, Department of Environmental Science, Stockholm University, Stockholm 114 18, Sweden
| | - Daniele Marini
- Department of Environmental Toxicology, Uppsala University, Uppsala 754 36, Sweden; Department of Veterinary Medicine, University of Perugia, Perugia 06126, Italy
| | - Vanessa Brouard
- Department of Environmental Toxicology, Uppsala University, Uppsala 754 36, Sweden
| | - Oskar Karlsson
- Science for Life Laboratory, Department of Environmental Science, Stockholm University, Stockholm 114 18, Sweden
| | - Cecilia Berg
- Department of Environmental Toxicology, Uppsala University, Uppsala 754 36, Sweden
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2
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Li HM, Zhang YC, Li YY, Zhu QQ, Li J, Xu HM, Xiong YM, Qin ZF. Low concentrations of benzophenone-type UV-filters impair testis development in the amphibian Xenopus laevis. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2023; 254:106371. [PMID: 36529091 DOI: 10.1016/j.aquatox.2022.106371] [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: 11/03/2022] [Revised: 12/03/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
Benzophenone-type UV filters (BPs) are ubiquitous contaminants in aquatic environments, possibly posing ecological risks to aquatic populations. So far, little is known about the potential adverse effects of BPs on amphibians. Given their potential estrogenic property, we investigated the detrimental effects of the commonly used BPs, BP-3, BP-2, and BP-1, on testis development in amphibians using Xenopus laevis as a model species. Following exposure to 10, 100, 1000 nM BP-3, BP-2, or BP-1 from stages 45/46 to 52, tadpoles presented morphological abnormal testes, characterized by reduced gonomere size and testis area, coupled with suppressed cell proliferation. Meanwhile, the downregulation of testis-biased gene expression and the upregulation of ovary-biased gene expression were observed in BPs-treated testes. Moreover, the estrogen receptor (ER) antagonist ICI 182780 significantly antagonized ovary-biased gene upregulation caused by BPs, suggesting that the effects of BPs on testis differentiation could be mediated by ER, at least partially. Of note, the effects of BPs were not concentration-dependent, but the lowest concentration generally exerted significant effects. Altogether, these observations indicate that the three BPs inhibited testis differentiation and exerted feminizing effects. Importantly, when BP-2 exposure was extended to two months post-metamorphosis, testes of froglets were generally less-developed, with relatively fewer spermatocytes, more spermatogonia, and poorly formed seminiferous tubules. Considering the fact that the lowest concentration (10 nM) of BPs in this study are detectable in aquatic environments, we conclude that BP-3, BP-2, and BP-1, even at environmentally relevant concentrations, can retard testis differentiation at pre-metamorphic stages and cause testis dysgenesis after metamorphosis in the amphibian X. laevis. Our findings suggest that ubiquitous BPs in aquatic environments could pose a potential risk to amphibians.
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Affiliation(s)
- Hong-Mei Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; Ningxia Medical University, Yinchuan, Ningxia 750004, China
| | - Ying-Chi Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Ningxia Medical University, Yinchuan, Ningxia 750004, China
| | - Yuan-Yuan Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Qing-Qing Zhu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jie Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Ningxia Medical University, Yinchuan, Ningxia 750004, China
| | - Hai-Ming Xu
- Ningxia Medical University, Yinchuan, Ningxia 750004, China; Department of Occupational and Environmental Hygiene, School of Public Health and Management, Ningxia Medical University, Yinchuan, Ningxia 750004, China
| | - Yi-Ming Xiong
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhan-Fen Qin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
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Finlayson KA, Leusch FDL, van de Merwe JP. Review of ecologically relevant in vitro bioassays to supplement current in vivo tests for whole effluent toxicity testing - Part 1: Apical endpoints. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 851:157817. [PMID: 35970462 DOI: 10.1016/j.scitotenv.2022.157817] [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: 02/08/2022] [Revised: 05/12/2022] [Accepted: 07/31/2022] [Indexed: 06/15/2023]
Abstract
Whole effluent toxicity (WET) testing is commonly used to ensure that wastewater discharges do not pose an unacceptable risk to receiving environments. Traditional WET testing involves exposing animals to (waste)water samples to assess four major ecologically relevant apical endpoints: mortality, growth, development, and reproduction. Recently, with the widespread implementation of the 3Rs to replace, reduce and refine the use of animals in research and testing, there has been a global shift away from in vivo testing towards in vitro alternatives. However, prior to the inclusion of in vitro bioassays in regulatory frameworks, it is critical to establish their ecological relevance and technical suitability. This is part 1 of a two-part review that aims to identify in vitro bioassays that can be used in WET testing and relate them to ecologically relevant endpoints through toxicity pathways, providing the reader with a high-level overview of current capabilities. Part 1 of this review focuses on four apical endpoints currently included in WET testing: mortality, growth, development, and reproduction. For each endpoint, the link between responses at the molecular or cellular level, that can be measured in vitro, and the adverse outcome at the organism level were established through simplified toxicity pathways. Additionally, literature from 2015 to 2020 on the use of in vitro bioassays for water quality assessments was reviewed to identify a list of suitable bioassays for each endpoint. This review will enable the prioritization of relevant endpoints and bioassays for incorporation into WET testing.
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Affiliation(s)
| | - Frederic D L Leusch
- Australian Rivers Institute, Griffith University, Australia; School of Environment and Science, Griffith University, Gold Coast, Australia
| | - Jason P van de Merwe
- Australian Rivers Institute, Griffith University, Australia; School of Environment and Science, Griffith University, Gold Coast, Australia
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Smaga CR, Bock SL, Johnson JM, Parrott BB. Sex Determination and Ovarian Development in Reptiles and Amphibians: From Genetic Pathways to Environmental Influences. Sex Dev 2022; 17:99-119. [PMID: 36380624 DOI: 10.1159/000526009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 07/08/2022] [Indexed: 11/21/2023] Open
Abstract
BACKGROUND Reptiles and amphibians provide untapped potential for discovering how a diversity of genetic pathways and environmental conditions are incorporated into developmental processes that can lead to similar functional outcomes. These groups display a multitude of reproductive strategies, and whereas many attributes are conserved within groups and even across vertebrates, several aspects of sexual development show considerable variation. SUMMARY In this review, we focus our attention on the development of the reptilian and amphibian ovary. First, we review and describe the events leading to ovarian development, including sex determination and ovarian maturation, through a comparative lens. We then describe how these events are influenced by environmental factors, focusing on temperature and exposure to anthropogenic chemicals. Lastly, we identify critical knowledge gaps and future research directions that will be crucial to moving forward in our understanding of ovarian development and the influences of the environment in reptiles and amphibians. KEY MESSAGES Reptiles and amphibians provide excellent models for understanding the diversity of sex determination strategies and reproductive development. However, a greater understanding of the basic biology of these systems is necessary for deciphering the adaptive and potentially disruptive implications of embryo-by-environment interactions in a rapidly changing world.
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Affiliation(s)
- Christopher R Smaga
- Eugene P. Odum School of Ecology, University of Georgia, Athens, Georgia, USA
- Savannah River Ecology Laboratory, Aiken, South Carolina, USA
| | - Samantha L Bock
- Eugene P. Odum School of Ecology, University of Georgia, Athens, Georgia, USA
- Savannah River Ecology Laboratory, Aiken, South Carolina, USA
| | - Josiah M Johnson
- Eugene P. Odum School of Ecology, University of Georgia, Athens, Georgia, USA
- Savannah River Ecology Laboratory, Aiken, South Carolina, USA
| | - Benjamin B Parrott
- Eugene P. Odum School of Ecology, University of Georgia, Athens, Georgia, USA
- Savannah River Ecology Laboratory, Aiken, South Carolina, USA
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Mentor A, Wänn M, Brunström B, Jönsson M, Mattsson A. Bisphenol AF and Bisphenol F Induce Similar Feminizing Effects in Chicken Embryo Testis as Bisphenol A. Toxicol Sci 2021; 178:239-250. [PMID: 33010167 PMCID: PMC7706397 DOI: 10.1093/toxsci/kfaa152] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The plastic component bisphenol A (BPA) impairs reproductive organ development in various experimental animal species. In birds, effects are similar to those caused by other xenoestrogens. Because of its endocrine disrupting activity, BPA is being substituted with other bisphenols in many applications. Using the chicken embryo model, we explored whether the BPA alternatives bisphenol AF (BPAF), bisphenol F (BPF), and bisphenol S (BPS) can induce effects on reproductive organ development similar to those induced by BPA. Embryos were exposed in ovo from embryonic day 4 (E4) to vehicle, BPAF at 2.1, 21, 210, and 520 nmol/g egg, or to BPA, BPF, or BPS at 210 nmol/g egg and were dissected on embryonic day 19. Similar to BPA, BPAF and BPF induced testis feminization, manifested as eg testis-size asymmetry and ovarian-like cortex in the left testis. In the BPS-group, too few males were alive on day 19 to evaluate any effects on testis development. We found no effects by any treatment on ovaries or Müllerian ducts. BPAF and BPS increased the gallbladder-somatic index and BPAF, BPF and BPS caused increased embryo mortality. The overall lowest-observed-adverse-effect level for BPAF was 210 nmol/g egg based on increased mortality, increased gallbladder-somatic index, and various signs of testis feminization. This study demonstrates that the BPA replacements BPAF, BPF, and BPS are embryotoxic and suggests that BPAF is at least as potent as BPA in inducing estrogen-like effects in chicken embryos. Our results support the notion that these bisphenols are not safe alternatives to BPA.
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Affiliation(s)
- Anna Mentor
- Department of Environmental Toxicology, Uppsala University, SE-752 36 Uppsala, Sweden.,Centre for Reproductive Biology in Uppsala (CRU), Uppsala, Sweden
| | - Mimmi Wänn
- Department of Environmental Toxicology, Uppsala University, SE-752 36 Uppsala, Sweden
| | - Björn Brunström
- Department of Environmental Toxicology, Uppsala University, SE-752 36 Uppsala, Sweden.,Centre for Reproductive Biology in Uppsala (CRU), Uppsala, Sweden
| | - Maria Jönsson
- Department of Environmental Toxicology, Uppsala University, SE-752 36 Uppsala, Sweden.,Centre for Reproductive Biology in Uppsala (CRU), Uppsala, Sweden
| | - Anna Mattsson
- Department of Environmental Toxicology, Uppsala University, SE-752 36 Uppsala, Sweden.,Centre for Reproductive Biology in Uppsala (CRU), Uppsala, Sweden
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Impact of Estrogens Present in Environment on Health and Welfare of Animals. Animals (Basel) 2021; 11:ani11072152. [PMID: 34359280 PMCID: PMC8300725 DOI: 10.3390/ani11072152] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 07/07/2021] [Accepted: 07/19/2021] [Indexed: 12/21/2022] Open
Abstract
Simple Summary Estrogens are a group of steroid hormones that recently have gained even more attention in the eyes of scientists. There is an ongoing discussion in the scientific community about their relevance as environmental contaminants and the danger they pose to animal health and welfare. In available literature we can find many examples of their negative effects and mechanisms that are involved with such phenomena. Abstract Nowadays, there is a growing interest in environmental pollution; however, knowledge about this aspect is growing at an insufficient pace. There are many potential sources of environmental contamination, including sex hormones—especially estrogens. The analyzed literature shows that estrone (E1), estradiol (E2), estriol (E3), and synthetic ethinyloestradiol (EE2) are the most significant in terms of environmental impact. Potential sources of contamination are, among others, livestock farms, slaughterhouses, and large urban agglomerations. Estrogens occurring in the environment can negatively affect the organisms, such as animals, through phenomena such as feminization, dysregulation of natural processes related to reproduction, lowering the physiological condition of the organisms, disturbances in the regulation of both proapoptotic and anti-apoptotic processes, and even the occurrence of neoplastic processes thus drastically decreasing animal welfare. Unfortunately, the amount of research conducted on the negative consequences of their impact on animal organisms is many times smaller than that of humans, despite the great richness and diversity of the fauna. Therefore, there is a need for further research to help fill the gaps in our knowledge.
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Babalola OO, Truter JC, Archer E, van Wyk JH. Exposure Impacts of Environmentally Relevant Concentrations of a Glufosinate Ammonium Herbicide Formulation on Larval Development and Thyroid Histology of Xenopus laevis. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2021; 80:717-725. [PMID: 32948887 DOI: 10.1007/s00244-020-00758-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Accepted: 09/05/2020] [Indexed: 06/11/2023]
Abstract
Thyroid hormones play critical roles in body growth and development as well as reproduction. They also influence the activities of a wider variety of tissues and biological functions, such as osmoregulation, metabolism, and especially metamorphosis in organisms, such as frogs. These complex activities of thyroid hormones are prone to disruption by agricultural pesticides, often leading to modulation of growth and the reproductive system in particular. These substances include Glufosinate ammonium, Glyphosates, Imazapyr, Penoxsulam, and Diquat dibromide among other herbicides. In this study, the standardized Xenopus Metamorphosis Assay protocol was used to assess the potential thyroid-modulatory properties of the Glufosinate ammonium Basta formulation, at relevant environmental concentrations (0.05 mg/L, 0.15 mg/L, and 0.25 mg/L) for 21 days. The results showed that this formulation only reduced the hind-limb length among the morphological endpoints. Histological evaluation showed that the mean thyroid gland area and the mean thyroidal follicle epithelium height were significantly increased following 0.15 and 0.25 mg/L exposures. The present study confirmed that this Basta formulation interacts with the thyroid axis and therefore potentially pose health hazard to amphibian in particular and potentially metamorphic aquatic vertebrates. Furthermore, the result is a signal of inherent potential thyroid disrupting activities that must be further investigated and characterised in some of the aquatic herbicide formulations to safeguard the aquatic biodiversity.
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Affiliation(s)
- Oluwaseun O Babalola
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa.
- Zoology and Environmental Biology, Lagos State University, Lagos, Nigeria.
| | - J Christoff Truter
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
- Department of Paraclinical Sciences, University of Pretoria, Pretoria, South Africa
| | - Edward Archer
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | - Johannes H van Wyk
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
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Babalola OO, van Wyk HJ. Exposure Impacts of Diquat dibromide herbicide formulation on amphibian larval development. Heliyon 2021; 7:e06700. [PMID: 33912705 PMCID: PMC8066383 DOI: 10.1016/j.heliyon.2021.e06700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 08/14/2020] [Accepted: 03/31/2021] [Indexed: 12/21/2022] Open
Abstract
Many anthropogenic chemicals in general, and specifically aquatic herbicide formulations have the potential to modulate the thyroid pathways of the endocrine system of aquatic organisms, because they are normally applied directly into the aquatic system, to manage aquatic weeds. These thyroidal effects have been widely linked with disruption in developmental and reproductive processes. In fact, the exposure impacts of many of these substances on metamorphic organisms could produce a precocious metamorphosis. Using Xenopus Metamorphosis Assay (XEMA) protocol, this study assessed the thyroidal effects of environmentally relevant concentrations of Diquat dibromide at 0.05, 0.11, and 0.14 mg/L on Xenopus laevis metamorphosis. The formulation significantly reduced both the fore and hind limb lengths, and disrupted the developmental stage at concentrations of 0.11 and 0.14 mg/L, with a median at NF-stage 57, while median of NF-stage 60 was recorded in the control. Histopathologically, although there was no significant difference in thyroid gland area, the thyroid colloidal area was significantly reduced at 0.14 mg/L, while the mean height of the thyroid follicle increased at 0.05 mg/L The result indicates an extra-thyroidal pathway, due to the dissociation between stage developmental effects and thyroid histopathology. The role of stress pathway occasioned by oxidative mode of action, involving lipid peroxidation and cell damage observed in this study need further investigation, in order to further characterize the physiological and ecological effects on wildlife.
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Affiliation(s)
- Oluwaseun Olusegun Babalola
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, 7600, South Africa
- Ecotoxicology & Ecophysiology Unit, Department of Zoology & Environmental Biology, Lagos State University, Lagos, Nigeria
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Gao J, Shen W. Xenopus in revealing developmental toxicity and modeling human diseases. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 268:115809. [PMID: 33096388 DOI: 10.1016/j.envpol.2020.115809] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 10/01/2020] [Accepted: 10/09/2020] [Indexed: 06/11/2023]
Abstract
The Xenopus model offers many advantages for investigation of the molecular, cellular, and behavioral mechanisms underlying embryo development. Moreover, Xenopus oocytes and embryos have been extensively used to study developmental toxicity and human diseases in response to various environmental chemicals. This review first summarizes recent advances in using Xenopus as a vertebrate model to study distinct types of tissue/organ development following exposure to environmental toxicants, chemical reagents, and pharmaceutical drugs. Then, the successful use of Xenopus as a model for diseases, including fetal alcohol spectrum disorders, autism, epilepsy, and cardiovascular disease, is reviewed. The potential application of Xenopus in genetic and chemical screening to protect against embryo deficits induced by chemical toxicants and related diseases is also discussed.
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Affiliation(s)
- Juanmei Gao
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 311121, China; College of Life and Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Wanhua Shen
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 311121, China.
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11
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Nemesházi E, Gál Z, Ujhegyi N, Verebélyi V, Mikó Z, Üveges B, Lefler KK, Jeffries DL, Hoffmann OI, Bókony V. Novel genetic sex markers reveal high frequency of sex reversal in wild populations of the agile frog (Rana dalmatina) associated with anthropogenic land use. Mol Ecol 2020; 29:3607-3621. [PMID: 32799395 DOI: 10.1111/mec.15596] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/22/2020] [Accepted: 08/06/2020] [Indexed: 12/30/2022]
Abstract
Populations of ectothermic vertebrates are vulnerable to environmental pollution and climate change because certain chemicals and extreme temperatures can cause sex reversal during early ontogeny (i.e. genetically female individuals develop male phenotype or vice versa), which may distort population sex ratios. However, we have troublingly little information on sex reversals in natural populations, due to unavailability of genetic sex markers. Here, we developed a genetic sexing method based on sex-linked single nucleotide polymorphism loci to study the prevalence and fitness consequences of sex reversal in agile frogs (Rana dalmatina). Out of 125 juveniles raised in laboratory without exposure to sex-reversing stimuli, 6 showed male phenotype but female genotype according to our markers. These individuals exhibited several signs of poor physiological condition, suggesting stress-induced sex reversal and inferior fitness prospects. Among 162 adults from 11 wild populations in North-Central Hungary, 20% of phenotypic males had female genotype according to our markers. These individuals occurred more frequently in areas of anthropogenic land use; this association was attributable to agriculture and less strongly to urban land use. Female-to-male sex-reversed adults had similar body mass as normal males. We recorded no events of male-to-female sex reversal either in the laboratory or in the wild. These results support recent suspicions that sex reversal is widespread in nature, and suggest that human-induced environmental changes may contribute to its pervasiveness. Furthermore, our findings indicate that sex reversal is associated with stress and poor health in early life, but sex-reversed individuals surviving to adulthood may participate in breeding.
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Affiliation(s)
- Edina Nemesházi
- Lendület Evolutionary Ecology Research Group Plant Protection Institute Centre for Agricultural Research, Budapest, Hungary
| | - Zoltán Gál
- NARIC Agricultural Biotechnology Institute, Gödöllő, Hungary
| | - Nikolett Ujhegyi
- Lendület Evolutionary Ecology Research Group Plant Protection Institute Centre for Agricultural Research, Budapest, Hungary
| | - Viktória Verebélyi
- Lendület Evolutionary Ecology Research Group Plant Protection Institute Centre for Agricultural Research, Budapest, Hungary
| | - Zsanett Mikó
- Lendület Evolutionary Ecology Research Group Plant Protection Institute Centre for Agricultural Research, Budapest, Hungary
| | - Bálint Üveges
- Lendület Evolutionary Ecology Research Group Plant Protection Institute Centre for Agricultural Research, Budapest, Hungary
| | - Kinga Katalin Lefler
- Department of Aquaculture, Faculty of Agricultural and Environmental Sciences, Institute for Conservation of Natural Resources, Szent István University, Gödöllő, Hungary
| | - Daniel Lee Jeffries
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | | | - Veronika Bókony
- Lendület Evolutionary Ecology Research Group Plant Protection Institute Centre for Agricultural Research, Budapest, Hungary
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12
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Li Y, Shen Y, Li J, Cai M, Qin Z. Transcriptomic analysis identifies early cellular and molecular events by which estrogen disrupts testis differentiation and causes feminization in Xenopus laevis. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2020; 226:105557. [PMID: 32645606 DOI: 10.1016/j.aquatox.2020.105557] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 06/11/2023]
Abstract
Extensive studies have shown that estrogenic endocrine-disrupting chemicals (EDCs) can disrupt testis differentiation and even cause feminization in vertebrates. However, little is known about the mechanisms by which estrogenic EDCs disrupt testis differentiation. Here, we employed Xenopus laevis, a model amphibian species sensitive to estrogenic EDCs, to explore the molecular and cellular events by which 17β-estradiol (E2) disrupts testis differentiation and causes feminization. Following waterborne exposure to E2 from stage 45/46, genetically male X. laevis were confirmed to undergo testis differentiation inhibition and ovary differentiation activation at stages 52 and 53, ultimately displaying gonadal feminization at stage 66. Using a time-course RNA sequencing approach, we then identified thousands of differentially expressed transcripts (DETs) in genetically male gonad-mesonephros complexes at stages 48, 50 and 52 (the window for testis differentiation) between E2 treatment and the control. Enrichment analysis suggests alterations in cell proliferation, extracellular matrix, and cell motility following E2 exposure. Further verification by multiple methods demonstrated that E2 inhibited cell proliferation, disrupted extracellular matrix, and altered cell motility in the genetically male gonads compared with controls, implying that these events together contributed to testis differentiation disruptions and feminization in X. laevis. This study for the first time uncovered some of the early molecular and cellular events by which estrogen disrupts testicular differentiation and causes feminization in X. laevis. These new findings improve our understanding of the mechanisms by which estrogenic EDCs disrupt testicular differentiation in vertebrates.
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Affiliation(s)
- Yuanyuan Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yanping Shen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jinbo Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Man Cai
- 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; University of Chinese Academy of Sciences, Beijing, 100049, China.
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13
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Shen Y, Li Y, Zhu M, Li J, Qin Z. Transcriptional changes caused by estrogenic endocrine disrupting chemicals in gonad-mesonephros complexes of genetic male Xenopus laevis: Multiple biomarkers for early detection of testis differentiation disruption. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 726:138522. [PMID: 32335401 DOI: 10.1016/j.scitotenv.2020.138522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 04/01/2020] [Accepted: 04/05/2020] [Indexed: 06/11/2023]
Abstract
Our recent study revealed some early molecular and cellular events in which 17β-estradiol (E2) disrupted testis differentiation and resulted in feminization in Xenopus laevis (the African clawed frog), an ideal species for studying reproductive endocrine disruption by estrogenic endocrine disrupting chemicals (EDCs). On this basis, we aimed to develop multiple biomarkers for early detection of testis differentiation disruption by estrogenic EDCs in X. laevis. Tadpoles at stage 45/46 were exposed to four known estrogenic EDCs with different estrogenic activities, including E2, diethylstilbestrol (DES), mestranol (MES) and 4-n-nonyphenol (NP). At stage 53, gonadal morphological and histological changes as well as altered sex-dimorphic gene expression in gonad-mesonephros complexes (GMCs) showed that these estrogenic EDCs disrupted testis differentiation and caused feminization to different degrees. Then we measured transcriptional changes of 48 candidate genes, which are believed to be associated with E2-induced testis differentiation alterations, in GMCs at stage 50. As a result, 19 genes were found to be transcriptionally altered by all test chemicals and proposed as promising biomarkers for early detection of testis differentiation disruption by estrogenic EDCs. Finally, all biomarker responses were integrated as integrated biomarker response (IBR) index to characterize testis differentiation disruption by these estrogenic EDCs in X. laevis. Compared with the methods used in previous studies, the multiple biomarker test using X. laevis at early developmental stages largely shortens the exposure duration, thereby achieving the goal of rapid detection. Certainly, the biomarker test needs further validations in the future study.
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Affiliation(s)
- Yanping Shen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuanyuan Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Zhu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinbo Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhanfen Qin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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Cai M, Li YY, Zhu M, Li JB, Qin ZF. Evaluation of the effects of low concentrations of bisphenol AF on gonadal development using the Xenopus laevis model: A finding of testicular differentiation inhibition coupled with feminization. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 260:113980. [PMID: 31991354 DOI: 10.1016/j.envpol.2020.113980] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 01/08/2020] [Accepted: 01/12/2020] [Indexed: 06/10/2023]
Abstract
Developmental exposures to estrogenic chemicals possibly cause structural and functional abnormalities of reproductive organs in vertebrates. Bisphenol AF (BPAF), a bisphenol A (BPA) analogue, has been shown to have higher estrogenic activity than BPA, but little is known about the effects of BPAF on gonadal development, particularly gonadal differentiation. We aimed to determine whether low concentrations of BPAF could disrupt gonadal differentiation and subsequent development using Xenopus laevis, a model species for studying feminizing effects of estrogenic chemicals. X. laevis tadpoles were exposed to BPAF (1, 10, 100 nM) or 17β-estradiol (E2, positive control) from stages 45/46 to 53 and 66 in a semi-static exposure system, with a prolonged treatment with the highest concentration to the eighth week post-metamorphosis (WPM8). Gonadal morphology and histology as well as sexually dimorphic gene expression were examined to evaluate the effects of BPAF. All concentrations of BPAF caused changes in testicular morphology at different developmental stages compared with controls. Specifically, at stage 53, BPAF like E2 resulted in decreases in both the size and the number of gonadal metameres (gonomeres) in testes, looking like ovaries. Some of BPAF-treated testes remained segmented and even became discontinuous and fragmented at subsequent stages. Histological abnormalities were also observed in BPAF-treated testes, such as ovarian cavity at stages 53 and 66 and poorly developed seminiferous tubules on WPM8. At the molecular level, BPAF inhibited expression of male highly expressed genes in testes at stage 53. Correspondingly, BPAF, like E2, inhibited cell proliferation in testes at stage 50. All results show that low concentrations of BPAF inhibited testicular differentiation and subsequent development in X. laevis, along with feminizing effects to some degree. Our finding implies a risk of BPAF to the male reproductive system of vertebrates including humans.
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Affiliation(s)
- Man Cai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuan-Yuan Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Min Zhu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jin-Bo Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhan-Fen Qin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
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Li JB, Li YY, Shen YP, Zhu M, Li XH, Qin ZF. 2,2',4,4'-tetrabromodipheny ether (BDE-47) disrupts gonadal development of the Africa clawed frog (Xenopus laevis). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2020; 221:105441. [PMID: 32045789 DOI: 10.1016/j.aquatox.2020.105441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 01/22/2020] [Accepted: 02/04/2020] [Indexed: 06/10/2023]
Abstract
Previous studies have shown that BDE-47, one of the most abundant polybrominated diphenyl ethers (PBDEs) congeners, has a weak estrogenic activity, but it has remained unclear whether BDE-47 disrupts gonadal development and causes male-to-female sex reversal in lower vertebrates, with limited and controversial data. The present study aimed to determine the effects of BDE-47 on gonadal development in Xenopus laevis, a model amphibian species for studying adverse effects of estrogenic chemicals on reproductive development. X. laevis at stage 45/46 were exposed to BDE-47 (0.5, 5, 50 nM) in semi-static system, with 1 nM 17β-estradiol (E2) as the positive control. When reaching stage 53, tadpoles were examined for gonadal morphology, histology and sex-dimorphic gene expression. The phenotypic sex (gonadal morphology and histology) of each BDE-47-treated tadpole matched its genetic sex, showing no sex-reversal, whereas one half of genetic males treated with E2 displayed ovarian-like features. However, some genetic males (26%) in the 50 nM BDE-47 treatment group were found to contain more germ cells clumping together in the medulla, along with an increasing tendency of the gonad length/kidney length ratio in males, resembling feminizing outcomes of E2. These observations seem to suggest that BDE-47 exerted weak feminizing effects. However, BDE-47 induced increases in expression of both female-biased genes and male-biased genes in two sexes, which disagrees with feminizing outcomes, suggesting complicated effects of BDE-47 on gonadal development. Taken together, all results demonstrate that nanomolar BDE-47 disrupted gonadal development and exerted weak feminizing effects, but not resulted in male-to-female sex reversal in X. laevis.
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Affiliation(s)
- Jin-Bo Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan-Yuan Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan-Ping Shen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Zhu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xing-Hong Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhan-Fen Qin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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Aronzon CM, Peluso J, Coll CP. Mixture toxicity of copper and nonylphenol on the embryo-larval development of Rhinella arenarum. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:13985-13994. [PMID: 32036534 DOI: 10.1007/s11356-020-07857-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 01/23/2020] [Indexed: 06/10/2023]
Abstract
Copper and nonylphenol are two commonly found chemicals in the aquatic environment, particularly in the distribution area of the amphibian Rhinella arenarum. The current work evaluated the lethal toxicity of equitoxic and non-equitoxic binary mixtures of copper and nonylphenol on embryos and larvae of the South America toad by means of the standardized test, AMPHITOX. Joint toxicity of mixtures was assessed in several proportions of these compounds at different exposure times and was analyzed at different level of mortality effect (LC10, LC50 and LC90). Considering the LC50, the equitoxic mixture was always antagonistic independently of the exposure time and the developmental stage. Joint toxicity showed mainly an antagonistic pattern; nonetheless, some time-dependent additive interactions were observed. Regarding the LC10, synergistic interactions were found in embryos and larvae exposed to two different mixture proportions at several exposure times. This highlights the possible synergism of these chemicals at environmentally relevant concentrations. These results point out the relevance of assessing joint toxicity of environmental pollutants for environmental risk assessment.
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Affiliation(s)
- Carolina Mariel Aronzon
- Instituto de Investigación e Ingeniería Ambiental, IIIA, Universidad Nacional de San Martín, CONICET, 3iA, Campus Miguelete, 25 de mayo y Francia (1650), San Martin, Provincia de Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Julieta Peluso
- Instituto de Investigación e Ingeniería Ambiental, IIIA, Universidad Nacional de San Martín, CONICET, 3iA, Campus Miguelete, 25 de mayo y Francia (1650), San Martin, Provincia de Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Cristina Pérez Coll
- Instituto de Investigación e Ingeniería Ambiental, IIIA, Universidad Nacional de San Martín, CONICET, 3iA, Campus Miguelete, 25 de mayo y Francia (1650), San Martin, Provincia de Buenos Aires, Argentina.
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
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Song W, Lu H, Wu K, Zhang Z, Shuk-Wa Lau E, Ge W. Genetic evidence for estrogenicity of bisphenol A in zebrafish gonadal differentiation and its signalling mechanism. JOURNAL OF HAZARDOUS MATERIALS 2020; 386:121886. [PMID: 31887561 DOI: 10.1016/j.jhazmat.2019.121886] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 12/09/2019] [Accepted: 12/10/2019] [Indexed: 06/10/2023]
Abstract
Bisphenol A (BPA) can induce endocrine disorders in humans and animals. In this study, we used several zebrafish mutants deficient in estrogen production and signalling, which could be valuable for evaluating estrogenic activities and mechanisms of EDCs. With low endogenous estrogens, the all-male aromatase mutant (cyp19a1a-/-) is expected to be more responsive to estrogenic exposure, and mutants of nuclear estrogen receptors (nERs; esr1-/-, esr2a-/- and esr2b-/-) alone or in combination would allow us to evaluate the action mechanisms of estrogenic EDCs. Exposure to BPA could rescue the all-male phenotype of the cyp19a1a-/- mutant, delayed gonadal development in both sexes, resulting in infertility or subfertility, and caused follicle atresia in females and impairment of spermatogenesis in males. To understand the mechanisms of these effects, we tested BPA in cyp19a1a and nER mutants of different combinations. The feminizing effect of BPA on sexual differentiation was dependent on nERs, in particular esr2a. As for males, nERs were also involved in BPA-induced impairment of spermatogenesis. Taken together, with genome editing technology our study provides the most comprehensive genetic evidence for estrogenic activities of BPA in zebrafish and its action mechanisms. This study also establishes a powerful platform for studying other EDCs with estrogenic activity.
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Affiliation(s)
- Weiyi Song
- Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa, Macau, 999078, China
| | - Huijie Lu
- Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa, Macau, 999078, China
| | - Kun Wu
- Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa, Macau, 999078, China
| | - Zhiwei Zhang
- Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa, Macau, 999078, China
| | - Esther Shuk-Wa Lau
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, 999077, Hong Kong, China
| | - Wei Ge
- Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa, Macau, 999078, China.
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Zhu Q, Liu L, Zhou X, Ma M. In silico study of molecular mechanisms of action: Estrogenic disruptors among phthalate esters. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 255:113193. [PMID: 31521998 DOI: 10.1016/j.envpol.2019.113193] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 06/29/2019] [Accepted: 09/06/2019] [Indexed: 05/22/2023]
Abstract
Phthalate esters (PAEs), as widely used plasticizers, have been concerned for their possible disruption of estrogen functions via binding to and activating the transcription of estrogen receptors (ERs). Nevertheless, the computational interpretation of the mechanism of ERs activities modulated by PAEs at the molecular level is still insufficient, which hinders the reliable screening of the ERs-active PAEs with high speed and high throughput. To bridge the gap, the in silico simulations considering the effects of coactivators were accomplished to explore the molecular mechanism of action for the purpose of predicting the estrogenic potencies of PAEs. The transcriptional activation functions of human ERα (hERα) modulated by PAEs is predicted via the simulations including binding interaction of PAEs and hERα, conformational changes of PAEs-hERα complexes and recruitment of coactivators. Molecular insight into the diverse estrogen mechanism of action among PAEs with regard to hERα agonists and selective estrogen receptor modulators (SERMs) is provided. Agonist-modulated conformational change of hERα leads to the optimal exposure of its Activation Function 2 (AF-2) surface which, in turn, facilitates the recruitment of coactivators, therefore promoting the transcriptional activation functions of hERα. Conversely, binding interaction of hERα with SERMs among PAEs leads to the conformational change with blocked AF-2 surface, thus preventing the recruitment of coactivators and consequently inhibiting the AF-2 activity. The two-hybrid recombinant yeast is experimentally used for verification. The established in silico evaluation methodology exhibits great promise to speed up the prediction of chemicals which work as hERα agonist or SERMs.
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Affiliation(s)
- Qian Zhu
- State Key Joint Laboratory of ESPC, School of Environment, Tsinghua University, Beijing 100084, China
| | - Lanhua Liu
- State Key Joint Laboratory of ESPC, School of Environment, Tsinghua University, Beijing 100084, China
| | - Xiaohong Zhou
- State Key Joint Laboratory of ESPC, School of Environment, Tsinghua University, Beijing 100084, China.
| | - Mei Ma
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
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Fort DJ, Mathis M, Fort C, Fort TD, Guiney PD, Weeks JA. Polybrominated Diphenylether (DE-71) Exposure Skews Phenotypic Sex Ratio, and Alters Steroid Hormone Levels and Steroidogenic Enzyme Activities in Juvenile Silurana tropicalis. Toxicol Sci 2019; 172:63-74. [PMID: 31393593 DOI: 10.1093/toxsci/kfz181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/24/2019] [Accepted: 07/24/2019] [Indexed: 11/12/2022] Open
Abstract
The impact of the brominated flame-retardant mixture, DE-71, on gonadal steroidogenesis during sexual differentiation in Silurana tropicalis was examined. A partial lifecycle study exposing S. tropicalis to varying concentrations of DE-71 (0.0, 0.65, 1.3, 2.5, and 5.0 μg/L [nominal]) was conducted from early gastrula-stage embryo to 150 d post-metamorphosis (dpm). Exposure of S. tropicalis to DE-71 induced liver necrosis and induced abnormal ovary development characterized by previtellogenic oocyte necrosis and arrested development of vitellogenic oocytes in females in a concentration-dependent manner. Decreased mean plasma DHT and T, gonad T, and increased mean plasma E2 levels were found in 150 dpm DE-71-treated male S. tropicalis compared to controls. Plasma E2 levels in females were not significantly altered compared to control S. tropicalis, although lower plasma and gonad T were detected. Mean gonadal CYP 19 aromatase activity in both male and female S. tropicalis exposed to DE-71 was not appreciably affected. Decreased mean male 5α-reductase and CYP17 activities in both male and females were observed compared to control frogs. Overall, these studies suggested that PBDE exposure induced liver necrosis and abnormal ovary development; and reduced circulating and gonadal androgens resulting in a phenotypic skew in sex ratio toward the female sex in S. tropicalis.
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Affiliation(s)
| | | | - Chelsea Fort
- Fort Environmental Laboratories, Inc. Stillwater, OK.,Current Address - Office of the Chief Medical Examiner of Oklahoma - Central Division, Oklahoma City, OK
| | - Troy D Fort
- Fort Environmental Laboratories, Inc. Stillwater, OK.,Current Address - Cognitive and Neurobiological Approaches to Plasticity (CNAP), Department of Psychological Sciences, Kansas State University, Manhattan, KS
| | - Patrick D Guiney
- S.C. Johnson & Son, Racine, WI.,Current Address - University of Wisconsin, Stoughton, WI
| | - John A Weeks
- S.C. Johnson & Son, Racine, WI.,Current Address - Weeks Entox, Knoxville, TN
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Scaia MF, de Gregorio LS, Franco-Belussi L, Succi-Domingues M, de Oliveira C. Gonadal, body color, and genotoxic alterations in Lithobates catesbeianus tadpoles exposed to nonylphenol. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:22209-22219. [PMID: 31152429 DOI: 10.1007/s11356-019-05403-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 05/06/2019] [Indexed: 06/09/2023]
Abstract
Endocrine disrupting chemicals are one of the most important factors contributing to worldwide amphibian decline. The 4-nonylphenol (NP) is a degradation product of several compounds, such as detergents and pesticides, affecting the aquatic environment. Here, we test whether treatment with NP has an effect on developing ovarian tissue, nuclear abnormalities in erythrocytes, and body darkness in pre-metamorphic tadpoles of the bullfrog Lithobates catesbeianus. Tadpoles were exposed for 14 days to three different concentrations of NP (1, 10, and 100 μg/L) besides the control group, which was maintained only with water. After determining body coloration, animals were euthanized and gonads and blood were collected and processed for histology and genotoxic analysis. Even though most animals were females, intersex tadpoles were observed in control and treated groups and there were no males in any group. The highest concentration of NP showed an increase in atretic oocytes, but the area corresponding to somatic compartment and early and late germ cells were not affected. Furthermore, all treated groups presented higher amount of nuclear abnormalities in erythrocytes and body darkening when compared with the control group. These results suggest that NP causes genetic damage and morphological alterations in L. catesbeianus tadpoles by disrupting oogenesis, inducing genotoxicity and increasing body coloration. Its effects on gonadal development could cause future impairments in reproduction, while its deleterious effects on genotoxicity and body pigmentation could be used as a biomarker of effect to this compound.
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Affiliation(s)
- María Florencia Scaia
- Post-graduate Program in Animal Biology, Department of Biology, São Paulo State University (UNESP), São José do Rio Preto, São Paulo, 15054-000, Brazil
- Instituto de Biodiversidad y Biología Experimental y Aplicada-CONICET, C1428EGA, Autonomous City of Buenos Aires, Argentina
- Laboratorio de Neuroendocrinología y Comportamiento, Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, C1428EGA, Autonomous City of Buenos Aires, Argentina
- Departamento de Biologia, Instituto de Biociências, Letras e Ciências Exatas - UNESP/IBILCE, Rua Cristóvão Colombo, 2265, Bairro: Jardim Nazareth, São José do Rio Preto, SP, 15054-000, Brazil
| | - Lara Salgueiro de Gregorio
- Post-graduate Program in Animal Biology, Department of Biology, São Paulo State University (UNESP), São José do Rio Preto, São Paulo, 15054-000, Brazil
| | - Lilian Franco-Belussi
- Departamento de Biologia, Instituto de Biociências, Letras e Ciências Exatas - UNESP/IBILCE, Rua Cristóvão Colombo, 2265, Bairro: Jardim Nazareth, São José do Rio Preto, SP, 15054-000, Brazil.
- Instituto de Biociências (InBio), Universidade Federal de Mato Grosso do Sul UFMS, Campo Grande, Brazil.
| | - Maysa Succi-Domingues
- Departamento de Biologia, Instituto de Biociências, Letras e Ciências Exatas - UNESP/IBILCE, Rua Cristóvão Colombo, 2265, Bairro: Jardim Nazareth, São José do Rio Preto, SP, 15054-000, Brazil
| | - Classius de Oliveira
- Departamento de Biologia, Instituto de Biociências, Letras e Ciências Exatas - UNESP/IBILCE, Rua Cristóvão Colombo, 2265, Bairro: Jardim Nazareth, São José do Rio Preto, SP, 15054-000, Brazil
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Rozenblut-Kościsty B, Ogielska M, Hahn J, Kleemann D, Kossakowski R, Tamschick S, Schöning V, Krüger A, Lutz I, Lymberakis P, Kloas W, Stöck M. Impacts of the synthetic androgen Trenbolone on gonad differentiation and development - comparisons between three deeply diverged anuran families. Sci Rep 2019; 9:9623. [PMID: 31270347 PMCID: PMC6610071 DOI: 10.1038/s41598-019-45985-4] [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: 10/12/2018] [Accepted: 06/20/2019] [Indexed: 11/25/2022] Open
Abstract
Using a recently developed approach for testing endocrine disruptive chemicals (EDCs) in amphibians, comprising synchronized tadpole exposure plus genetic and histological sexing of metamorphs in a flow-through-system, we tested the effects of 17β-Trenbolone (Tb), a widely used growth promoter in cattle farming, in three deeply diverged anuran families: the amphibian model species Xenopus laevis (Pipidae) and the non-models Bufo(tes) viridis (Bufonidae) and Hyla arborea (Hylidae). Trenbolone was applied in three environmentally and/or physiologically relevant concentrations (0.027 µg/L (10-10 M), 0.27 µg/L (10-9 M), 2.7 µg/L (10-8 M)). In none of the species, Tb caused sex reversals or masculinization of gonads but had negative species-specific impacts on gonad morphology and differentiation after the completion of metamorphosis, independently of genetic sex. In H. arborea and B. viridis, mounting Tb-concentration correlated positively with anatomical abnormalities at 27 µg/L (10-9 M) and 2.7 µg/L (10-8 M), occurring in X. laevis only at the highest Tb concentration. Despite anatomical aberrations, histologically all gonadal tissues differentiated seemingly normally when examined at the histological level but at various rates. Tb-concentration caused various species-specific mortalities (low in Xenopus, uncertain in Bufo). Our data suggest that deep phylogenetic divergence modifies EDC-vulnerability, as previously demonstrated for Bisphenol A (BPA) and Ethinylestradiol (EE2).
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Affiliation(s)
- Beata Rozenblut-Kościsty
- Department of Evolutionary Biology and Conservation of Vertebrates, Wroclaw University, Sienkiewicza 21, 50-335, Wroclaw, Poland
| | - Maria Ogielska
- Department of Evolutionary Biology and Conservation of Vertebrates, Wroclaw University, Sienkiewicza 21, 50-335, Wroclaw, Poland
| | - Juliane Hahn
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587, Berlin, Germany
| | - Denise Kleemann
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587, Berlin, Germany
| | - Ronja Kossakowski
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587, Berlin, Germany
| | - Stephanie Tamschick
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587, Berlin, Germany
| | - Viola Schöning
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587, Berlin, Germany
| | - Angela Krüger
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587, Berlin, Germany
| | - Ilka Lutz
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587, Berlin, Germany
| | - Petros Lymberakis
- Natural History Museum of Crete, University of Crete, Knossou Ave., 71409, Heraklion, Crete, Greece
| | - Werner Kloas
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587, Berlin, Germany
- Department of Endocrinology, Institute of Biology, Faculty of Life Sciences, Humboldt University, Unter den Linden 6, 10099, Berlin, Germany
| | - Matthias Stöck
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587, Berlin, Germany.
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Fort DJ, Mathis MB, Fort CE, Fort HM, Fort TD, Guiney PD, Weeks JA. Effect of perfluorooctanesulfonate exposure on steroid hormone levels and steroidogenic enzyme activities in juvenile Silurana tropicalis. J Appl Toxicol 2019; 39:1066-1078. [PMID: 30847954 DOI: 10.1002/jat.3794] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/08/2019] [Accepted: 02/08/2019] [Indexed: 01/02/2023]
Abstract
The impact of the perfluoro-chemical, perfluorooctanesulfonate (PFOS), on gonadal steroidogenesis during sexual differentiation in Silurana tropicalis was examined because of its ubiquity in the environment, bioaccumulative nature and potential to disturb endocrine activity. A partial life cycle study exposing S. tropicalis to varying concentrations of PFOS 0.06, 0.13, 0.25, 0.50 and 1.0 mg PFOS/L [nominal]) was conducted. Gonad and plasma samples were collected from juvenile control specimens and organisms exposed to PFOS from early embryo through 150 days post-metamorphosis. Gonad CYP17, aromatase and 5α-reductase activities were measured. Plasma estradiol, testosterone, dihydrotestosterone (DHT) and gonadal testosterone were measured in both males and females. Increased plasma DHT and gonadal testosterone were found in PFOS-treated juvenile male S. tropicalis compared to controls. Decreased plasma estradiol, but not testosterone, was detected in PFOS-treated female S. tropicalis compared to controls. Plasma DHT was not detected and an increase in gonadal testosterone was detected in PFOS-treated female frogs. Female S. tropicalis exposed to PFOS exhibited a concentration-related decrease in the mean aromatase activity, but not 5α-reductase. PFOS exposure in male frogs induced a concentration-related increase in 5α-reductase activity, but did not alter aromatase activity compared to control frogs. A concentration-related increase in CYP 17,20-lyase activity, but not 17-hydroxylase activity, was found in both female and male S. tropicalis exposed to PFOS.
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Affiliation(s)
| | | | | | - Hayley M Fort
- Fort Environmental Laboratories, Stillwater, OK, USA
| | - Troy D Fort
- Fort Environmental Laboratories, Stillwater, OK, USA
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Yuan S, Huang C, Ji X, Ma M, Rao K, Wang Z. Prediction of the combined effects of multiple estrogenic chemicals on MCF-7 human breast cancer cells and a preliminary molecular exploration of the estrogenic proliferative effects and related gene expression. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 160:1-9. [PMID: 29783106 DOI: 10.1016/j.ecoenv.2018.05.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/05/2018] [Accepted: 05/11/2018] [Indexed: 06/08/2023]
Abstract
The environmental risks of environmental estrogens (EEs) are often assessed via the same mode of action in the concentration addition (CA) model, neglecting the complex combined mechanisms at the genetic level. In this study, the cell proliferation effects of estrone, 17α-ethinylestradiol, 17β-estradiol, estriol, diethylstilbestrol, estradiol valerate, bisphenol A, 4-tert-octylphenol and 4-nonylphenol were determined individually using the CCK-8 method, and the proliferation effects of a multicomponent mixture of estrogenic chemicals mixed at equipotent concentrations using a fixed-ratio design were studied using estrogen-sensitive MCF-7 cells. Furthermore, transcription factors related to cell proliferation were analyzed using RT-PCR assays to explore the potential molecular mechanisms related to the estrogenic proliferative effects. The results showed that the estrogenic chemicals act together in an additive mode, and the combined proliferative effects could be predicted more accurately by the response addition model than the CA model with regard to their adverse outcomes. Furthermore, different signaling pathways were involved depending on the different mixtures. The RT-PCR analyses showed that different estrogens have distinct avidities and preferences for different estrogen receptors at the gene level. Furthermore, the results indicated that estrogenic mixtures increased ERα, PIK3CA, GPER, and PTEN levels and reduced Akt1 level to display combined estrogenicity. These findings indicated that the potential combined environmental risks were greater than those found in some specific assessment procedures based on a similar mode of action due to the diversity of environmental pollutions and their multiple unknown modes of action. Thus, more efforts are needed for mode-of-action-driven analyses at the molecular level. Furthermore, to more accurately predict and assess the individual responses in vivo from the cellular effects in vitro, more parameters and correction factors should be taken into consideration in the addition model.
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Affiliation(s)
- Shengwu Yuan
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chao Huang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoya Ji
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mei Ma
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment Science, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Kaifeng Rao
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Zijian Wang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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Brunelli E. Histological and ultrastructural alterations of the Italian newt (Lissotriton italicus) skin after exposure to ecologically relevant concentrations of nonylphenol ethoxylates. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2018; 60:17-27. [PMID: 29653385 DOI: 10.1016/j.etap.2018.04.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/05/2018] [Accepted: 04/06/2018] [Indexed: 06/08/2023]
Abstract
Nonylphenol ethoxylates (NPEs) are well known endocrine disruptors. Widespread environmental contamination from NPEs is an issue of great concern. Despite amphibians are often exposed to such contaminants, very little attention has been dedicated to this vertebrate group. No information is available on the effects of NPEs onto the amphibian skin and only few reports have been conducted on fish. Here, histological and ultrastructural modifications of the skin have been evaluated in the Italian newt Lissotriton italicus. After a short-term exposure to two ecologically relevant concentrations of NP, severe pathological alterations, both dose and time-dependent, have been observed. The main effects were an increased mucous secretion, the dilation of the endomembrane, the wrinkling of the epidermal surface, the appearance of tubercles, the increased cellular turnover, continuous shedding processes. Some of the described skin alterations can easily interfere with physiological functions, such as osmoregulation and body protection, with detrimental consequences for the amphibian populations.
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Affiliation(s)
- Elvira Brunelli
- Department of Biology, Ecology and Earth Science (DiBEST), University of Calabria, Via P. Bucci 4/B, Rende, Cosenza, 87036, Italy.
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Ockleford C, Adriaanse P, Berny P, Brock T, Duquesne S, Grilli S, Hernandez-Jerez AF, Bennekou SH, Klein M, Kuhl T, Laskowski R, Machera K, Pelkonen O, Pieper S, Stemmer M, Sundh I, Teodorovic I, Tiktak A, Topping CJ, Wolterink G, Aldrich A, Berg C, Ortiz-Santaliestra M, Weir S, Streissl F, Smith RH. Scientific Opinion on the state of the science on pesticide risk assessment for amphibians and reptiles. EFSA J 2018; 16:e05125. [PMID: 32625798 PMCID: PMC7009658 DOI: 10.2903/j.efsa.2018.5125] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Following a request from EFSA, the Panel on Plant Protection Products and their Residues developed an opinion on the science to support the potential development of a risk assessment scheme of plant protection products for amphibians and reptiles. The coverage of the risk to amphibians and reptiles by current risk assessments for other vertebrate groups was investigated. Available test methods and exposure models were reviewed with regard to their applicability to amphibians and reptiles. Proposals were made for specific protection goals aiming to protect important ecosystem services and taking into consideration the regulatory framework and existing protection goals for other vertebrates. Uncertainties, knowledge gaps and research needs were highlighted.
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Fort DJ, Mathis MB, Guiney PD, Weeks JA. Inhibition of germinal vesicle breakdown in Xenopus oocytes in vitro by a series of substituted glycol ethers. J Appl Toxicol 2017; 38:628-637. [PMID: 29205417 DOI: 10.1002/jat.3567] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 09/28/2017] [Accepted: 10/16/2017] [Indexed: 01/31/2023]
Abstract
A 24 hour in vitro Xenopus oocyte maturation (germinal vesicle breakdown [GVBD]) assay developed by Pickford and Morris (Environmental Health Perspectives, 1999, 107, 285-292) was used to screen a series of substituted glycol ethers (GEs). Substituted GEs included: ethylene glycol monomethyl ether (EGME); EG monoethyl ether (EGEE); EG monopropyl ether (EGPE); EG monobutyl ether (EGBE); EG monohexyl ether (EGHE); diethylene glycol monomethyl ether (DGME); triethylene glycol monomethyl ether (TGME); ethylene glycol monophenyl ether (EGPhE); EG monobenzyl ether (EGBeE); EG diphenyl ether (EGDPhE); and propylene glycol monophenyl ether (PGPhE). The GEs inhibited progesterone- or androstenedione-induced GVBD with the following relative potency: EGPhE > PGPhE > EGME >> EGEE ≥ EGBeE > EGPE >> EGBE >EGHE > EGDPhE >> DGME ≥ TGME, or EGPhE >> PGPhE >> EGBeE > EGDPhE > EGEE > EGME > EGPE > EGBE, EGHE, DGME and TGME, respectively. Further, [3 H]progesterone or [3 H]androstenedione binding affinities to the oocyte plasma membrane progesterone receptor (OMPR) or classical androgen receptor (AR) were: EGME > EGPhE ≥ PGPhE ≥ EGEE > EGBeE >> EGPE >> EGBE ≥ EGHE > EGDPhE, TGME, and DGME, or EGPhE > PGPhE >> EGBeE > EGDPhE >> EGEE ≥ EGME >> EGPE, EGBE, and EGHE > DGME and TGME, respectively. Binary joint mixture studies with the GVBD model using flutamide (AR antagonist) and EGPhE indicated that flutamide/EGPhE mixture acted in a concentration additive manner. The effects of substituted GE series, however, may be mediated through the OMPR; the potency of EGPhE may be the result of bimodal inhibition of both the OMPR and AR pathways.
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Affiliation(s)
- Douglas J Fort
- Fort Environmental Laboratories, Inc., Stillwater, OK, USA
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Gould PR, Cecala KK, Drukker SS, McKenzie BA, Van de Ven C. Biogeographical factors affecting the distribution of stream salamanders on the Cumberland Plateau, USA. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 599-600:1622-1629. [PMID: 28531969 DOI: 10.1016/j.scitotenv.2017.05.098] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 06/07/2023]
Abstract
Geophysical and climate conditions play an important role in the distribution of organisms at both fine and broad scales. Headwater streams integrate changes at broad geographical scales and serve as important regions of nutrient processing and support high biodiversity. Stream salamanders are important members of headwater aquatic communities as both predators and prey. Combined with their biphasic life histories and physiological requirements, stream amphibians may serve as indicators for headwater stream conditions. We surveyed 50 streams for salamander occupancy, across eight counties of the southern Cumberland Plateau in Tennessee for which we are unaware of any stream amphibian distribution data. Our objective was to determine what variables best-predicted stream amphibian occupancy among species with variable life histories and habitat needs. Models were generated to determine the effects of elevation, catchment forest cover, and total catchment size as indicators of stream condition. We found species showed no significant responses to forest cover. Though forest cover has previously been the primary predictor of stream amphibian occupancy in streams across the United States, stream amphibian occupancy of the southern Cumberland Plateau was most closely associated with elevation and catchment size. Thus, the unique topography of the southern Cumberland Plateau may instead be the more important factor driving occupancy patterns. Despite limited evidence in this study for negative human impacts on salamander occupancy, low occupancy and abundance relative to other ecoregions suggests either poor quality habitat or large historic impacts. Developing a more comprehensive understanding of regional stream salamander occupancy patterns is necessary to ensure effective management and habitat conservation in a region with limited description of stream ecology.
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Affiliation(s)
- P R Gould
- Department of Biology, University of the South, Sewanee, TN 37383, USA
| | - K K Cecala
- Department of Biology, University of the South, Sewanee, TN 37383, USA.
| | - S S Drukker
- Department of Biology, University of the South, Sewanee, TN 37383, USA
| | - B A McKenzie
- Department of Biology, University of the South, Sewanee, TN 37383, USA
| | - C Van de Ven
- Earth and Environmental Systems Department, The University of the South, Sewanee, TN 37383, USA
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28
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Environmental Review & Case Study: Evaluating the Significance of Certain Pharmaceuticals and Emerging Pathogens in Raw Water Supplies. ACTA ACUST UNITED AC 2017. [DOI: 10.1017/s1466046611000196] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Balabanič D, Filipič M, Krivograd Klemenčič A, Žegura B. Raw and biologically treated paper mill wastewater effluents and the recipient surface waters: Cytotoxic and genotoxic activity and the presence of endocrine disrupting compounds. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 574:78-89. [PMID: 27623529 DOI: 10.1016/j.scitotenv.2016.09.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 08/31/2016] [Accepted: 09/04/2016] [Indexed: 05/25/2023]
Abstract
Paper mill effluents are complex mixtures containing different toxic compounds including endocrine-disrupting (EDCs) and genotoxic compounds. In the present study non-concentrated raw and biologically treated wastewaters from two paper mill plants with different paper production technologies i) Paper mill A uses virgin fibres, and ii) Paper mill B uses recycled fibres for paper production and the corresponding receiving surface waters, were assessed for their cytotoxic/genotoxic activity with SOS/umuC, Ames MPF 98/100 Aqua, and comet assay with human hepatoma HepG2 cells. In addition the levels of seven selected EDCs were quantified in wastewater samples and receiving surface waters. All investigated EDCs were confirmed in raw and biologically treated effluents from both paper mills with concentrations being markedly higher in Paper mill B effluents. In the receiving surface waters three of the studied EDCs were determined downstream of both paper mills effluent discharge. The wastewater samples and the recipient surface water samples from Paper mill A were not mutagenic for bacteria and did not induce DNA damage in HepG2 cells. On the contrary, half of the raw wastewater samples from Paper mill B were mutagenic whereas biologically treated wastewater and the recipient surface water samples were negative. In HepG2 cells most of the raw and biologically treated wastewater samples from Paper mill B as well as surface water samples collected downstream of Paper mill B effluent discharge induced DNA damage. The results confirmed that genotoxic contaminants were present only in wastewaters from Paper mill B that uses recycled fibres for paper production, and that the combined aerobic and anaerobic wastewater treatment procedure efficiently reduced contaminants that are bacterial mutagens, but not those that induce DNA damage in HepG2 cells. This study highlights that in addition to chemical analyses bioassays are needed for a comprehensive toxicological evaluation of complex wastewater samples.
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Affiliation(s)
- Damjan Balabanič
- Faculty of Industrial Engineering, Šegova ulica 112, SI-8000 Novo mesto, Slovenia.
| | - Metka Filipič
- National Institute of Biology, Department of Genetic Toxicology and Cancer Biology, Večna pot 111, SI-1000 Ljubljana, Slovenia.
| | - Aleksandra Krivograd Klemenčič
- University of Ljubljana, Faculty of Civil and Geodetic Engineering, Institute for Sanitary Engineering, Hajdrihova 28, SI-1000 Ljubljana, Slovenia.
| | - Bojana Žegura
- National Institute of Biology, Department of Genetic Toxicology and Cancer Biology, Večna pot 111, SI-1000 Ljubljana, Slovenia.
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Complete Genome Sequence of the Nonylphenol-Degrading Bacterium Sphingobium cloacae JCM 10874T. GENOME ANNOUNCEMENTS 2016; 4:4/6/e01358-16. [PMID: 27932652 PMCID: PMC5146444 DOI: 10.1128/genomea.01358-16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sphingobium cloacae JCM 10874T can degrade phenolic endocrine-disrupting chemicals, nonylphenol, and octylphenol. Here, we report the complete genome sequence of the JCM 10874T strain.
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31
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Li YY, Chen J, Qin ZF. Determining the optimal developmental stages of Xenopus laevis for initiating exposures to chemicals for sensitively detecting their feminizing effects on gonadal differentiation. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 179:134-142. [PMID: 27611864 DOI: 10.1016/j.aquatox.2016.09.002] [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: 06/27/2016] [Revised: 08/31/2016] [Accepted: 09/01/2016] [Indexed: 06/06/2023]
Abstract
Xenopus laevis is an important model for detecting feminizing effects of endocrine disrupting chemicals (EDCs) on amphibians because its genetic males can be induced to phenotypic females by estrogenic chemicals. It is crucial that chemical exposures begin at sensitive developmental stages for gonadal sex-reversal in X. laevis. To determine the optimal stages for initiating exposures, we investigated gonadal sex-reversal induced by low concentrations of 17α-ethinylestradiol (EE2) when exposures were initiated at different stages (3/4, 45/46, 48 and 50) until stage 58. We found that 0.1nM EE2 resulted in 85%, 86%, 43%, and 19% intersex, whereas 1nM EE2 caused 77%, 81%, 17%, and 8% phenotypic females, when genetic male tadpoles were exposed from stages 3/4, 45/46, 48 and 50, respectively. The data show the sensitivity of X. laevis gonads to EE2 at stages 45/46 is similar with that at stages 3/4, but the sensitivity decreases at stage 48 and stage 50, displaying a developmental stage-dependent manner. In another experiment using the offspring of another pair of frogs, we confirmed high sensitivity of X. laevis gonads at stages 45/46 to low concentrations of EE2. Considering that stages 45/46 tadpoles are easier to manipulate and have higher survival rates than earlier embryos, we propose that stages 45/46 are the optimal stages for initiating exposure for detecting feminizing effects of EDCs on gonadal differentiation in X. laevis. The developmental stages for initiating exposures we determined will guarantee the high sensitivity for detecting feminizing effects of EDCs with low estrogenic activities on gonadal differentiation in X. laevis. Also, our study suggests that gonadal differentiation in X. laevis possibly begins at stages 45/46, but not at later stages.
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Affiliation(s)
- Yuan-Yuan Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Juan Chen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhan-Fen Qin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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32
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Tamschick S, Rozenblut-Kościsty B, Ogielska M, Kekenj D, Gajewski F, Krüger A, Kloas W, Stöck M. The plasticizer bisphenol A affects somatic and sexual development, but differently in pipid, hylid and bufonid anurans. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 216:282-291. [PMID: 27285164 DOI: 10.1016/j.envpol.2016.05.091] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 05/30/2016] [Accepted: 05/31/2016] [Indexed: 05/10/2023]
Abstract
Due to their terrestrial habitats and aquatic reproduction, many amphibians are both very vulnerable and highly suitable bioindicators. The plasticizer bisphenol A (BPA) is one of the most produced chemical substances worldwide, and knowledge on its impacts on humans and animals is mounting. BPA is used for the industrial production of polycarbonate plastics and epoxy resins and found in a multitude of consumer products. Studies on BPA have involved mammals, fish and the fully aquatic anuran model Xenopus laevis. However, our knowledge about the sexual development of non-model, often semi-terrestrial anuran amphibians remains poor. Using a recently developed experimental design, we simultaneously applied BPA to two non-model species (Hyla arborea, Hylidae; Bufo viridis, Bufonidae) and the model X. laevis (Pipidae), compared their genetic and phenotypic sex for detection of sex reversals, and studied sexual development, focusing on anatomical and histological features of gonads. We compared three concentrations of BPA (0.023, 2.28 and 228 μg/L) to control groups in a high-standard flow-through-system, and tested whether conclusions, drawn from the model species, can be extrapolated to non-model anurans. In contrast to previous studies on fish and Xenopus, often involving dosages much higher than most environmental pollution data, we show that BPA causes neither the development of mixed sex nor of sex-reversed individuals (few, seemingly BPA-independent sex reversals) in all focal species. However, environmentally relevant concentrations, as low as 0.023 μg/L, were sufficient to provoke species-specific anatomically and histologically detectable impairments of gonads, and affected morphological traits of metamorphs. As the intensity of these effects differed between the three species, our data imply that BPA diversely affects amphibians with different evolutionary history, sex determination systems and larval ecologies. These results highlight the role of amphibians as a sensitive group that is responsive to environmental pollution.
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Affiliation(s)
- Stephanie Tamschick
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587 Berlin, Germany.
| | - Beata Rozenblut-Kościsty
- Department of Evolutionary Biology and Conservation of Vertebrates, Wroclaw University, Sienkiewicza 21, 50-335 Wroclaw, Poland.
| | - Maria Ogielska
- Department of Evolutionary Biology and Conservation of Vertebrates, Wroclaw University, Sienkiewicza 21, 50-335 Wroclaw, Poland.
| | - David Kekenj
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587 Berlin, Germany.
| | - Franz Gajewski
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587 Berlin, Germany.
| | - Angela Krüger
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587 Berlin, Germany.
| | - Werner Kloas
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587 Berlin, Germany.
| | - Matthias Stöck
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587 Berlin, Germany.
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Viljoen IM, Bornman R, Bouwman H. DDT exposure of frogs: A case study from Limpopo Province, South Africa. CHEMOSPHERE 2016; 159:335-341. [PMID: 27317939 DOI: 10.1016/j.chemosphere.2016.06.023] [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: 12/28/2015] [Revised: 06/03/2016] [Accepted: 06/06/2016] [Indexed: 06/06/2023]
Abstract
Amphibians are globally under pressure with environmental contaminants contributing to this. Despite caution aired more than 80 years ago of threats posed to amphibians by DDT spraying for disease vector control, no data have been published on concentrations or effects of DDT contamination in frogs from areas where DDT is actively sprayed to control the insect vectors of malaria. In this study, we sampled fat bodies of Xenopus laevis and Xenopus muelleri naturally occurring in an area where indoor residual spraying of DDT is employed and from adjacent, non-sprayed, areas. ΣDDT concentrations ranged between <LOQ and 280 ng/g ww (wet weight) from the non-sprayed area, and 5.5-910 ng/g ww from the sprayed area, but statistical significance could not be shown. We observed significant asymmetric testicular morphology in frogs from the sprayed area, possibly due to endocrine disruption by compounds such as the DDTs. A previous study from the same area found very high concentrations of DDT in the eggs of the Grey Heron Ardea cinerea. This suggests that the DDT we found in frogs may have contributed to DDT loadings higher in the food web. These findings, combined with other studies from this area, support the need to reduce and eventually move away from DDT in malaria control safely and sustainably.
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Affiliation(s)
- Ignatius M Viljoen
- Research Unit: Environmental Sciences and Management, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa; SA Medical Research Council Centre for TB Research, DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Francie van Zijl Drive, Tygerberg, 7505, South Africa.
| | - Riana Bornman
- SA Medical Research Council Centre & University of Pretoria Centre for Sustainable Malaria Control (MRC & UP CSMC), School of Health, Systems and Public Health, University of Pretoria, Pretoria, 0028, South Africa
| | - Hindrik Bouwman
- Research Unit: Environmental Sciences and Management, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa
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34
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Finlayson KA, Leusch FDL, van de Merwe JP. The current state and future directions of marine turtle toxicology research. ENVIRONMENT INTERNATIONAL 2016; 94:113-123. [PMID: 27236406 DOI: 10.1016/j.envint.2016.05.013] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 05/13/2016] [Accepted: 05/14/2016] [Indexed: 05/14/2023]
Abstract
Chemical contamination of marine turtles has been well documented in the literature, although information on the toxicological effects of these contaminants is poorly understood. This paper systematically and quantitatively presents the available marine turtle toxicological research (excluding oil chemicals and natural toxins) and the related fields of cell line establishment and biomarkers as indicators of exposure. Examination of the published literature identified a total of 49 papers on marine turtle toxicology, which were split into three categories: toxicity studies (n=33, 67%), cell line establishment (n=7, 14%), and publications using biomarkers (n=13, 27%). Toxicity studies were further broken down into four subcategories: those correlating contaminants with toxicological endpoints (n=16, 48%); in vitro exposure experiments (n=11, 33%); in vivo exposure experiments (n=5, 15%); and screening risk assessments using hazard quotients (n=3, 9%). In quantitatively assessing the literature, trends and gaps in this field of research were identified. This paper highlights the need for more marine turtle toxicology research on all species, particularly using high throughput and non-invasive in vitro assays developed for marine turtle cells, including investigations into further toxicological endpoints and mixture effects. This will provide more comprehensive species-specific assessment of the impacts of chemical contaminants on these threatened animals, and improve conservation and management strategies globally.
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Affiliation(s)
- Kimberly A Finlayson
- Smart Water Research Centre, Australian Rivers Institute, Griffith School of Environment, Griffith University, Gold Coast, Australia.
| | - Frederic D L Leusch
- Smart Water Research Centre, Australian Rivers Institute, Griffith School of Environment, Griffith University, Gold Coast, Australia
| | - Jason P van de Merwe
- Smart Water Research Centre, Australian Rivers Institute, Griffith School of Environment, Griffith University, Gold Coast, Australia
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Lambert MR, Giller GSJ, Skelly DK, Bribiescas RG. Septic systems, but not sanitary sewer lines, are associated with elevated estradiol in male frog metamorphs from suburban ponds. Gen Comp Endocrinol 2016; 232:109-14. [PMID: 26795918 DOI: 10.1016/j.ygcen.2016.01.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 01/11/2016] [Indexed: 02/04/2023]
Abstract
Suburban neighborhoods are a dominant type of human land use. Many housing regions globally rely on septic systems, rather than sanitary sewers, for wastewater management. There is evidence that septic systems may contaminate waterbodies more than sewer lines. There is also mounting evidence that human activities contaminate waterways with endocrine-disrupting chemicals (EDCs), which alter wildlife sexual development. While endocrine disruption is often associated with intense activities such as agriculture or wastewater treatment plant discharges, recent evidence indicates that endocrine disruption is pervasive in frogs from suburban neighborhoods. In conjunction with other putative EDC sources, one hypothesis is that wastewater is contaminating suburban waterways with EDCs derived from pharmaceuticals or personal care products. Here, we measure estradiol (E2) in metamorphosing green frogs (Rana clamitans) from forested ponds and suburban ponds adjacent to either septic tanks or sanitary sewers. We show that E2 is highest in male frogs from septic neighborhoods and that E2 concentrations are significantly lower in male frogs from forested ponds and from ponds near sewers. These results indicate that septic tanks may be contaminating aquatic ecosystems differently than sewer lines. This pattern contrasts prior work showing no difference in EDC contamination or morphological endocrine disruption between septic and sewer neighborhoods, implying that suburbanization may have varying effects at multiple biological scales like physiology and anatomy.
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Affiliation(s)
- Max R Lambert
- School of Forestry and Environmental Studies, Yale University, 370 Prospect St, New Haven, CT 06511, USA; Reproductive Ecology Laboratory, Yale University, 21 Sachem St, New Haven, CT 06511, USA.
| | - Geoffrey S J Giller
- School of Forestry and Environmental Studies, Yale University, 370 Prospect St, New Haven, CT 06511, USA
| | - David K Skelly
- School of Forestry and Environmental Studies, Yale University, 370 Prospect St, New Haven, CT 06511, USA
| | - Richard G Bribiescas
- Reproductive Ecology Laboratory, Yale University, 21 Sachem St, New Haven, CT 06511, USA; Department of Anthropology, Yale University, 10 Sachem St, New Haven, CT 06511, USA
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36
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Haselman JT, Kosian PA, Korte JJ, Olmstead AW, Iguchi T, Johnson RD, Degitz SJ. Development of the Larval Amphibian Growth and Development Assay: effects of chronic 4-tert-octylphenol or 17β-trenbolone exposure inXenopus laevisfrom embryo to juvenile. J Appl Toxicol 2016; 36:1639-1650. [DOI: 10.1002/jat.3330] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 02/25/2016] [Accepted: 03/14/2016] [Indexed: 01/10/2023]
Affiliation(s)
| | - Patricia A. Kosian
- US EPA Mid-Continent Ecology Division; 6201 Congdon Blvd Duluth MN 55804 USA
| | - Joseph J. Korte
- US EPA Mid-Continent Ecology Division; 6201 Congdon Blvd Duluth MN 55804 USA
| | - Allen W. Olmstead
- US EPA Mid-Continent Ecology Division; 6201 Congdon Blvd Duluth MN 55804 USA
| | - Taisen Iguchi
- Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology; National Institutes of Natural Sciences; 5-1 Higashiyama, Myodaiji Okazaki Aichi 444-8787 Japan
| | - Rodney D. Johnson
- US EPA Mid-Continent Ecology Division; 6201 Congdon Blvd Duluth MN 55804 USA
| | - Sigmund J. Degitz
- US EPA Mid-Continent Ecology Division; 6201 Congdon Blvd Duluth MN 55804 USA
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Tamschick S, Rozenblut-Kościsty B, Ogielska M, Lehmann A, Lymberakis P, Hoffmann F, Lutz I, Kloas W, Stöck M. Sex reversal assessments reveal different vulnerability to endocrine disruption between deeply diverged anuran lineages. Sci Rep 2016; 6:23825. [PMID: 27029458 PMCID: PMC4814869 DOI: 10.1038/srep23825] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 03/15/2016] [Indexed: 01/17/2023] Open
Abstract
Multiple anthropogenic stressors cause worldwide amphibian declines. Among several poorly investigated causes is global pollution of aquatic ecosystems with endocrine disrupting compounds (EDCs). These substances interfere with the endocrine system and can affect the sexual development of vertebrates including amphibians. We test the susceptibility to an environmentally relevant contraceptive, the artificial estrogen 17α-ethinylestradiol (EE2), simultaneously in three deeply divergent systematic anuran families, a model-species, Xenopus laevis (Pipidae), and two non-models, Hyla arborea (Hylidae) and Bufo viridis (Bufonidae). Our new approach combines synchronized tadpole exposure to three EE2-concentrations (50, 500, 5,000 ng/L) in a flow-through-system and pioneers genetic and histological sexing of metamorphs in non-model anurans for EDC-studies. This novel methodology reveals striking quantitative differences in genetic-male-to-phenotypic-female sex reversal in non-model vs. model species. Our findings qualify molecular sexing in EDC-analyses as requirement to identify sex reversals and state-of-the-art approaches as mandatory to detect species-specific vulnerabilities to EDCs in amphibians.
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Affiliation(s)
- Stephanie Tamschick
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587 Berlin, Germany
| | - Beata Rozenblut-Kościsty
- Department of Evolutionary Biology and Conservation of Vertebrates, Wroclaw University, Sienkiewicza 21, 50-335 Wroclaw, Poland
| | - Maria Ogielska
- Department of Evolutionary Biology and Conservation of Vertebrates, Wroclaw University, Sienkiewicza 21, 50-335 Wroclaw, Poland
| | - Andreas Lehmann
- Federal Institute for Materials Research and Testing (BAM), Richard-Willstätter-Str. 11, D-12489 Berlin, Germany
| | - Petros Lymberakis
- Natural History Museum of Crete, University of Crete, Knossou Ave., 71409 Heraklion, Crete, Greece
| | - Frauke Hoffmann
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587 Berlin, Germany
| | - Ilka Lutz
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587 Berlin, Germany
| | - Werner Kloas
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587 Berlin, Germany
| | - Matthias Stöck
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301 & 310, D-12587 Berlin, Germany
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Qiu W, Zhao Y, Yang M, Farajzadeh M, Pan C, Wayne NL. Actions of Bisphenol A and Bisphenol S on the Reproductive Neuroendocrine System During Early Development in Zebrafish. Endocrinology 2016; 157:636-47. [PMID: 26653335 DOI: 10.1210/en.2015-1785] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Bisphenol A (BPA) is a well-known environmental, endocrine-disrupting chemical, and bisphenol S (BPS) has been considered a safer alternative for BPA-free products. The present study aims to evaluate the impact of BPA and BPS on the reproductive neuroendocrine system during zebrafish embryonic and larval development and to explore potential mechanisms of action associated with estrogen receptor (ER), thyroid hormone receptor (THR), and enzyme aromatase (AROM) pathways. Environmentally relevant, low levels of BPA exposure during development led to advanced hatching time, increased numbers of GnRH3 neurons in both terminal nerve and hypothalamus, increased expression of reproduction-related genes (kiss1, kiss1r, gnrh3, lhβ, fshβ, and erα), and a marker for synaptic transmission (sv2). Low levels of BPS exposure led to similar effects: increased numbers of hypothalamic GnRH3 neurons and increased expression of kiss1, gnrh3, and erα. Antagonists of ER, THRs, and AROM blocked many of the effects of BPA and BPS on reproduction-related gene expression, providing evidence that those three pathways mediate the actions of BPA and BPS on the reproductive neuroendocrine system. This study demonstrates that alternatives to BPA used in the manufacture of BPA-free products are not necessarily safer. Furthermore, this is the first study to describe the impact of low-level BPA and BPS exposure on the Kiss/Kiss receptor system during development. It is also the first report of multiple cellular pathways (ERα, THRs, and AROM) mediating the effects of BPA and BPS during embryonic development in any species.
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Affiliation(s)
- Wenhui Qiu
- School of Environmental and Chemical Engineering (W.Q., M.Y., C.P.), Shanghai University, Shanghai 200444, China; and Department of Physiology (W.Q., Y.Z., M.F., N.L.W.), David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095
| | - Yali Zhao
- School of Environmental and Chemical Engineering (W.Q., M.Y., C.P.), Shanghai University, Shanghai 200444, China; and Department of Physiology (W.Q., Y.Z., M.F., N.L.W.), David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095
| | - Ming Yang
- School of Environmental and Chemical Engineering (W.Q., M.Y., C.P.), Shanghai University, Shanghai 200444, China; and Department of Physiology (W.Q., Y.Z., M.F., N.L.W.), David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095
| | - Matthew Farajzadeh
- School of Environmental and Chemical Engineering (W.Q., M.Y., C.P.), Shanghai University, Shanghai 200444, China; and Department of Physiology (W.Q., Y.Z., M.F., N.L.W.), David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095
| | - Chenyuan Pan
- School of Environmental and Chemical Engineering (W.Q., M.Y., C.P.), Shanghai University, Shanghai 200444, China; and Department of Physiology (W.Q., Y.Z., M.F., N.L.W.), David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095
| | - Nancy L Wayne
- School of Environmental and Chemical Engineering (W.Q., M.Y., C.P.), Shanghai University, Shanghai 200444, China; and Department of Physiology (W.Q., Y.Z., M.F., N.L.W.), David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095
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Reddy TV, Flick R, Lazorchak JM, Smith ME, Wiechman B, Lattier DL. Experimental paradigm for in-laboratory proxy aquatic studies under conditions of static, non-flow-through chemical exposures. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2015; 34:2796-2802. [PMID: 26088724 DOI: 10.1002/etc.3121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 12/30/2014] [Accepted: 06/12/2015] [Indexed: 06/04/2023]
Abstract
Endocrine-disrupting chemicals (EDCs) such as 17α-ethynylestradiol, 17β-estradiol, estrone, and para-nonylphenol have been measured in wastewater-treatment plant effluents, surface waters, sediments, and sludge and have been shown to induce liver-specific vitellogenin (vtg) messenger RNA in male fathead minnows (Pimephales promelas). The purpose of the present study was to establish minimal concentrations of select EDCs necessary to induce transcription of vtg in 48-h static renewal exposures, as measured by quantitative real-time thermal cycle amplification. Adult males were exposed to 17α-ethynylestradiol, 17β-estradiol, estrone, and para-nonylphenol. Dose-dependent increases in vtg expression were significant with all chemicals tested. The lowest concentrations of these chemicals to induce measurable vtg expression, with significant difference from respective controls, were 17α-ethynylestradiol, 2.2 ng L(-1); para-nonylphenol, 13.9 μg L(-1); 17β-estradiol, 42.7 ng L(-1); and estrone, 46.7 ng L(-1), measured as 48-h average concentrations. The present experiments were designed to frame a commonly acceptable approach for investigators who conduct static, in-laboratory proxy environmental aquatic exposures. The present study highlights the need for investigators to report in peer-reviewed submissions the observed concentration values for minimal induction levels when measuring molecular responses to chemical exposures by means of real-time polymerase chain reaction, quantitative polymerase chain reaction, or other "omic" technologies.
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Affiliation(s)
- Tirumuru V Reddy
- National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, Ohio
| | - Robert Flick
- National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, Ohio
| | - James M Lazorchak
- National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, Ohio
| | - Mark E Smith
- Dynamac, US Environmental Protection Agency, Cincinnati, Ohio
| | - Barry Wiechman
- Dynamac, US Environmental Protection Agency, Cincinnati, Ohio
| | - David L Lattier
- National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, Ohio
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Mathieu-Denoncourt J, Wallace SJ, de Solla SR, Langlois VS. Plasticizer endocrine disruption: Highlighting developmental and reproductive effects in mammals and non-mammalian aquatic species. Gen Comp Endocrinol 2015; 219:74-88. [PMID: 25448254 DOI: 10.1016/j.ygcen.2014.11.003] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 10/30/2014] [Accepted: 11/03/2014] [Indexed: 10/24/2022]
Abstract
Due to their versatility, robustness, and low production costs, plastics are used in a wide variety of applications. Plasticizers are mixed with polymers to increase flexibility of plastics. However, plasticizers are not covalently bound to plastics, and thus leach from products into the environment. Several studies have reported that two common plasticizers, bisphenol A (BPA) and phthalates, induce adverse health effects in vertebrates; however few studies have addressed their toxicity to non-mammalian species. The aim of this review is to compare the effects of plasticizers in animals, with a focus on aquatic species. In summary, we identified three main chains of events that occur in animals exposed to BPA and phthalates. Firstly, plasticizers affect development by altering both the thyroid hormone and growth hormone axes. Secondly, these chemicals interfere with reproduction by decreasing cholesterol transport through the mitochondrial membrane, leading to reduced steroidogenesis. Lastly, exposure to plasticizers leads to the activation of peroxisome proliferator-activated receptors, the increase of fatty acid oxidation, and the reduction in the ability to cope with the augmented oxidative stress leading to reproductive organ malformations, reproductive defects, and decreased fertility.
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Affiliation(s)
- Justine Mathieu-Denoncourt
- Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada
| | - Sarah J Wallace
- Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada
| | - Shane R de Solla
- Wildlife and Landscape Science Directorate, Environment Canada, Burlington, ON L7R 4A6, Canada
| | - Valerie S Langlois
- Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada.
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41
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Wolff SE, Veldhoen N, Helbing CC, Ramirez CA, Malpas JM, Propper CR. Estrogenic environmental contaminants alter the mRNA abundance profiles of genes involved in gonadal differentiation of the American bullfrog. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 521-522:380-7. [PMID: 25863316 PMCID: PMC4440455 DOI: 10.1016/j.scitotenv.2015.02.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 02/06/2015] [Accepted: 02/09/2015] [Indexed: 05/08/2023]
Abstract
Wildlife and human populations are exposed to anthropogenic mixtures of chemicals in the environment that may adversely influence normal reproductive function and development. We determined the effects of exposure to estrogenic chemicals and wastewater effluent (WWE) on developing gonads of the American bullfrog, Rana (Lithobates) catesbeiana, a species whose widespread distribution make it an ideal model for environmental monitoring of endocrine effects of chemical contaminants. Premetamorphic bullfrog tadpoles were exposed to treatment vehicle, 17β-estradiol (E2; 10(-9)M) or 4-tert-octylphenol (OP; 10(-9)M, 10(-8)M, and 10(-7)M). Additionally, gonadal differentiation was evaluated in bullfrog tadpoles from a WWE-containing site versus those from a reference location receiving no WWE. In both studies, phenotypic sex, steroidogenic factor-1 (nr5a1), and aromatase (cyp19a1) mRNA levels using quantitative real-time PCR were determined. Exposure to E2 or OP did not alter sex ratios. In controls, both nr5a1 and cyp19a1 transcript levels exhibited sexual dimorphism, with males demonstrating higher levels of nr5a1 and females greater abundance of cyp19a1. However, E2 exposure increased cyp19a1 mRNA abundance in testes and decreased levels in ovaries, eliminating the sexual dimorphism observed in controls. E2-exposed males exhibited increased nr5a1 transcript levels in the testes compared to controls, while females demonstrated no E2 effect. OP treatment had no effect on female cyp19a1 mRNA abundance, but exposure to 10(-7)M OP increased testicular transcript levels. Treatment with 10(-9) and 10(-8)M OP, but not 10(-7)M, resulted in decreased abundance of nr5a1 transcript in both ovaries and testes. Animals from the field had sexually dimorphic gonadal levels of cyp19a1, but both sexes from the WWE site exhibited elevated cyp19a1 transcript abundance compared to the reference location. Individual chemical compounds and anthropogenic wastewater effluent dispersed within the environment influence the levels of gonadal mRNA encoding key proteins involved in gonadal differentiation.
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Affiliation(s)
- Stephanie E Wolff
- Department of Biological Sciences, S. Beaver St., Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Nik Veldhoen
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700, STN CSC, Victoria, British Columbia V8W 2Y2, Canada
| | - Caren C Helbing
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700, STN CSC, Victoria, British Columbia V8W 2Y2, Canada
| | - Claire A Ramirez
- Department of Biological Sciences, S. Beaver St., Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Janae M Malpas
- Department of Biological Sciences, S. Beaver St., Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Catherine R Propper
- Department of Biological Sciences, S. Beaver St., Northern Arizona University, Flagstaff, AZ 86011, USA.
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Abstract
Research on bisphenol A (BPA) as an environmental contaminant has now major regulatory implications toward the ecosystem health, and hence it is incumbent on scientists to do their research to the highest standards possible, in order that the most appropriate decisions are made to mitigate the impacts to aquatic wildlife. However, the contribution given so far appears rather fragmented. The present overview aims to collect available information on the effects of BPA on aquatic vertebrates and invertebrates to provide a general scenario and to suggest future developments toward more comprehensive approaches useful for aquatic species protection.
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Affiliation(s)
- Laura Canesi
- Department of Earth, Environment and Life Sciences, University of Genoa, Genova, Italy
| | - Elena Fabbri
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Campus of Ravenna, Ravenna, Italy
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Singh N, Reza KK, Ali MA, Agrawal VV, Biradar A. Self assembled DC sputtered nanostructured rutile TiO 2 platform for bisphenol A detection. Biosens Bioelectron 2015; 68:633-641. [DOI: 10.1016/j.bios.2015.01.041] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 12/31/2014] [Accepted: 01/19/2015] [Indexed: 02/07/2023]
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Bhandari RK, Deem SL, Holliday DK, Jandegian CM, Kassotis CD, Nagel SC, Tillitt DE, Vom Saal FS, Rosenfeld CS. Effects of the environmental estrogenic contaminants bisphenol A and 17α-ethinyl estradiol on sexual development and adult behaviors in aquatic wildlife species. Gen Comp Endocrinol 2015; 214:195-219. [PMID: 25277515 DOI: 10.1016/j.ygcen.2014.09.014] [Citation(s) in RCA: 167] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Revised: 08/08/2014] [Accepted: 09/20/2014] [Indexed: 12/12/2022]
Abstract
Endocrine disrupting chemicals (EDCs), including the mass-produced component of plastics, bisphenol A (BPA) are widely prevalent in aquatic and terrestrial habitats. Many aquatic species, such as fish, amphibians, aquatic reptiles and mammals, are exposed daily to high concentrations of BPA and ethinyl estradiol (EE2), estrogen in birth control pills. In this review, we will predominantly focus on BPA and EE2, well-described estrogenic EDCs. First, the evidence that BPA and EE2 are detectable in almost all bodies of water will be discussed. We will consider how BPA affects sexual and neural development in these species, as these effects have been the best characterized across taxa. For instance, such chemicals have been in many cases reported to cause sex-reversal of males to females. Even if these chemicals do not overtly alter the gonadal sex, there are indications that several EDCs might demasculinize male-specific behaviors that are essential for attracting a mate. In so doing, these chemicals may reduce the likelihood that these males reproduce. If exposed males do reproduce, the concern is that they will then be passing on compromised genetic fitness to their offspring and transmitting potential transgenerational effects through their sperm epigenome. We will thus consider how diverse epigenetic changes might be a unifying mechanism of how BPA and EE2 disrupt several processes across species. Such changes might also serve as universal species diagnostic biomarkers of BPA and other EDCs exposure. Lastly, the evidence that estrogenic EDCs-induced effects in aquatic species might translate to humans will be considered.
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Affiliation(s)
- Ramji K Bhandari
- Biological Sciences, University of Missouri, Columbia, MO 65211, USA; Columbia Environmental Research Center, U.S. Geological Survey, Columbia, MO 65201, USA
| | - Sharon L Deem
- Institute for Conservation Medicine, Saint Louis Zoo, Saint Louis, MO 63110, USA; Veterinary Clinical Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Dawn K Holliday
- Department of Biology and Environmental Science, Westminster College, Fulton, MO 65251, USA; Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Caitlin M Jandegian
- Columbia Environmental Research Center, U.S. Geological Survey, Columbia, MO 65201, USA; Institute for Conservation Medicine, Saint Louis Zoo, Saint Louis, MO 63110, USA; Masters in Public Health Program, University of Missouri, Columbia, MO 65211, USA
| | | | - Susan C Nagel
- Biological Sciences, University of Missouri, Columbia, MO 65211, USA; Obstetrics, Gynecology, & Women's Health, University of Missouri, Columbia, MO 65211, USA
| | - Donald E Tillitt
- Columbia Environmental Research Center, U.S. Geological Survey, Columbia, MO 65201, USA
| | | | - Cheryl S Rosenfeld
- Biomedical Sciences, University of Missouri, Columbia, MO 65211, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; Genetics Area Program Faculty Member, University of Missouri, Columbia, MO 65211, USA.
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Gröner F, Ziková A, Kloas W. Effects of the pharmaceuticals diclofenac and metoprolol on gene expression levels of enzymes of biotransformation, excretion pathways and estrogenicity in primary hepatocytes of Nile tilapia (Oreochromis niloticus). Comp Biochem Physiol C Toxicol Pharmacol 2015; 167:51-7. [PMID: 25236869 DOI: 10.1016/j.cbpc.2014.09.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 09/03/2014] [Accepted: 09/03/2014] [Indexed: 11/22/2022]
Abstract
The expression levels of key enzymes of the xenobiotic metabolism and excretion pathways concerning biotransformation phases I (cytochrome P4501A), II (glutathione S-transferase) and III (multidrug resistance protein) and of the estrogenic biomarker vitellogenin (vtg) were investigated in primary hepatocytes isolated from male Nile tilapia (Oreochromis niloticus) after exposure to diclofenac and metoprolol, two pharmaceuticals prevalent in the aquatic environment worldwide. The lowest test concentration (4×10(-9) M) was chosen to reflect an environmentally relevant exposure situation. Furthermore concentration dependent effects were investigated. Therefore a series of concentrations higher than the environmentally relevant range were used (10- and 100-fold). Diclofenac significantly induced all chosen biomarkers already at the environmentally relevant concentration indicating that biotransformation and elimination occur via the pathways under investigation. Estrogenic potential of this substance was demonstrated by VTG up-regulation as well. Metoprolol was either less effective than diclofenac or metabolized using different pathways. Key enzymes of the xenobiotic metabolism were less (CYP1A, GST) or not (MDRP) induced and a mild increase in vtg mRNA was detected only for 4×10(-8) M. No concentration-dependency for metoprolol was found.
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Affiliation(s)
- Frederike Gröner
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 301, 12587 Berlin, Germany.
| | - Andrea Ziková
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 301, 12587 Berlin, Germany
| | - Werner Kloas
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 301, 12587 Berlin, Germany; Department of Endocrinology, Institute of Biology, Humboldt University, Invalidenstr. 42, 10099 Berlin, Germany
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Liver histology and ultrastructure of the Italian newt (Lissotriton italicus): Normal structure and modifications after acute exposure to nonylphenol ethoxylates. ACTA ACUST UNITED AC 2014; 66:455-68. [DOI: 10.1016/j.etp.2014.09.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 09/02/2014] [Indexed: 11/18/2022]
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Säfholm M, Ribbenstedt A, Fick J, Berg C. Risks of hormonally active pharmaceuticals to amphibians: a growing concern regarding progestagens. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130577. [PMID: 25405966 PMCID: PMC4213589 DOI: 10.1098/rstb.2013.0577] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Most amphibians breed in water, including the terrestrial species, and may therefore be exposed to water-borne pharmaceuticals during critical phases of the reproductive cycle, i.e. sex differentiation and gamete maturation. The objectives of this paper were to (i) review available literature regarding adverse effects of hormonally active pharmaceuticals on amphibians, with special reference to environmentally relevant exposure levels and (ii) expand the knowledge on toxicity of progestagens in amphibians by determining effects of norethindrone (NET) and progesterone (P) exposure to 0, 1, 10 or 100 ng l(-1) (nominal) on oogenesis in the test species Xenopus tropicalis. Very little information was found on toxicity of environmentally relevant concentrations of pharmaceuticals on amphibians. Research has shown that environmental concentrations (1.8 ng l(-1)) of the pharmaceutical oestrogen ethinylestradiol (EE2) cause developmental reproductive toxicity involving impaired spermatogenesis in frogs. Recently, it was found that the progestagen levonorgestrel (LNG) inhibited oogenesis in frogs by interrupting the formation of vitellogenic oocytes at an environmentally relevant concentration (1.3 ng l(-1)). Results from the present study revealed that 1 ng NET l(-1) and 10 ng P l(-1) caused reduced proportions of vitellogenic oocytes and increased proportions of previtellogenic oocytes compared with the controls, thereby indicating inhibited vitellogenesis. Hence, the available literature shows that the oestrogen EE2 and the progestagens LNG, NET and P impair reproductive functions in amphibians at environmentally relevant exposure concentrations. The progestagens are of particular concern given their prevalence, the range of compounds and that several of them (LNG, NET and P) share the same target (oogenesis) at environmental exposure concentrations, indicating a risk for adverse effects on fertility in exposed wild amphibians.
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Affiliation(s)
- Moa Säfholm
- Department of Organismal Biology, Environmental Toxicology, Uppsala University, Norbyvägen 18A, 75236 Uppsala, Sweden
| | - Anton Ribbenstedt
- Department of Organismal Biology, Environmental Toxicology, Uppsala University, Norbyvägen 18A, 75236 Uppsala, Sweden
| | - Jerker Fick
- Department of Chemistry, Umeå University, KBC 6A, Linnaeus väg 6, 90187 Umeå, Sweden
| | - Cecilia Berg
- Department of Organismal Biology, Environmental Toxicology, Uppsala University, Norbyvägen 18A, 75236 Uppsala, Sweden
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Park CJ, Gye MC. Sensitization of vitellogenin gene expression by low doses of octylphenol is mediated by estrogen receptor autoregulation in the Bombina orientalis (Boulenger) male liver. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 156:191-200. [PMID: 25248154 DOI: 10.1016/j.aquatox.2014.08.013] [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: 02/08/2014] [Revised: 08/26/2014] [Accepted: 08/27/2014] [Indexed: 06/03/2023]
Abstract
This study aimed to elucidate the mechanisms by which alkylphenols disrupt endocrine function in wild amphibians in Korea. To this end, the effects of 4-tert-octylphenol (OP), 17β-estradiol (E2), and estrogen receptor (ER) agonists on the expression profiles of vitellogenin (VTG) and ERs were examined in livers obtained from male Bombina orientalis toads. A single injection of E2 (10μg/kg; 0.03μmol/kg) induced transcription of VTG mRNA at 2 days post injection; however, injection of either the ERα-selective agonist propyl-(1H)-pyrazole-1,3,5-triyl-trisphenol (PPT, 50μg/kg; 0.12μmol/kg) or the ERβ-selective agonist 2,3-bis-(4-hydroxyphenyl)-propionitrile (DPN, 50μg/kg; 0.20μmol/kg) did not affect the expression of VTG. This finding suggests that both ERα and ERβ are required to induce transcription of VTG in the male B. orientalis liver. Interestingly, E2, PPT, and DPN induced transcription of ERα, which was also reflected on the protein level; however, these alkylphenols did not affect ERβ transcription. Similarly, VTG transcription was induced by a single injection of 1-100mg/kg (0.04-484.66μmol/kg) OP, while 0.1mg/kg (0.48μmol/kg) OP had no effect on VTG transcription. This result suggests that the lowest observable effect concentration (LOEC) of OP for induction of VTG transcription in the male liver is 1mg/kg (4.84μmol/kg). Furthermore, treatment with E2 (10μg/kg; 0.03μmol/kg) or OP (1mg/kg; 4.84μmol/kg) significantly upregulated ERα transcription, and a 10mg/kg (48.46μmol/kg) dose of OP significantly upregulated ERβ transcription. The ER antagonist ICI 182,780 decreased the basal levels of ERα and ERβ mRNA, and also prevented E2-mediated and OP-mediated induction of VTG, ERα, and ERβ transcription. A second injection of 0.1mg/kg (0.48μmol/kg) OP after a two-day interval significantly upregulated the transcription of VTG and ERα, but not of ERβ. These results suggest that sensitization of VTG transcription by repeated exposure to OP is mediated by the induction of ERα. Different combinations of alkylphenols that are ubiquitous in the freshwater system in Korea could potentially exert a synergistic effect on endocrine disruption. Thus, chronic exposure to alkylphenols, even at their NOECs, could still disrupt endocrine function in B. orientalis.
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Affiliation(s)
- Chan Jin Park
- Department of Life Science and Institute for Natural Sciences, Hanyang University, Seoul 133-791, South Korea
| | - Myung Chan Gye
- Department of Life Science and Institute for Natural Sciences, Hanyang University, Seoul 133-791, South Korea.
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49
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Bissegger S, Martyniuk CJ, Langlois VS. Transcriptomic profiling in Silurana tropicalis testes exposed to finasteride. Gen Comp Endocrinol 2014; 203:137-45. [PMID: 24530632 DOI: 10.1016/j.ygcen.2014.01.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 01/24/2014] [Accepted: 01/28/2014] [Indexed: 01/14/2023]
Abstract
Investigations of endocrine disrupting chemicals found in aquatic ecosystems with estrogenic and androgenic modes of action have increased over the past two decades due to a surge of evidence of adverse effects in wildlife. Chemicals that disrupt androgen signalling and steroidogenesis can result in an imbalanced conversion of testosterone (T) into 17β-estradiol (E2) and other androgens such as 5α-dihydrotestosterone (5α-DHT). Therefore, a better understanding of how chemicals perturb these pathways is warranted. In this study, the brain, liver, and testes of Silurana tropicalis were exposed ex vivo to the human drug finasteride, a potent steroid 5α-reductase inhibitor and a model compound to study the inhibition of the conversion of T into 5α-DHT. These experiments were conducted (1) to determine organ specific changes in sex steroid production after treatment, and (2) to elucidate the transcriptomic response to finasteride in testicular tissue. Enzyme-linked immunosorbent assays were used to measure hormone levels in media following finasteride incubation for 6 h. Finasteride significantly increased T levels in the media of liver and testis tissue, but did not induce any changes in E2 and 5α-DHT production. Gene expression analysis was performed in frog testes and data revealed that finasteride treatment significantly altered 1,434 gene probes. Gene networks associated with male reproduction such as meiosis, hormone biosynthesis, sperm entry, gonadotropin releasing hormone were affected by finasteride exposure as well as other pathways such as oxysterol synthesis, apoptosis, and epigenetic regulation. For example, this study suggests that the mode of action by which finasteride induces cellular damage in testicular tissue as reported by others, is via oxidative stress in testes. This data also suggests that 5-reductase inhibition disrupts the expression of genes related to reproduction. It is proposed that androgen-disrupting chemicals may mediate their action via 5-reductases and that the effects of environmental pollutants are not limited to the androgen receptor signalling.
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Affiliation(s)
- Sonja Bissegger
- Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, ON, Canada.
| | - Christopher J Martyniuk
- Department of Biology and the Canadian River Institute, University of New Brunswick, NB, Canada.
| | - Valérie S Langlois
- Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, ON, Canada.
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50
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Urbatzka R, Lorenz C, Wiedemann C, Lutz I, Kloas W. Steroid exposure during larval development of Xenopus laevis affects mRNA expression of the reproductive pituitary-gonadal axis in a sex- and stage-dependent manner. Comp Biochem Physiol C Toxicol Pharmacol 2014; 160:1-8. [PMID: 24239592 DOI: 10.1016/j.cbpc.2013.11.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 10/30/2013] [Accepted: 11/06/2013] [Indexed: 01/28/2023]
Abstract
Steroids are known to influence the reproductive pituitary-gonadal axis in adult amphibians. Here, we studied the effects of hormones on pituitary and gonadal mRNA expression during the development of Xenopus laevis. Tadpoles at NF 58 (prometamorphosis) and at NF 66 (freshly metamorphosed) were exposed for three days to 17β-estradiol (E2), tamoxifen (TAM), testosterone (T), dihydrotestosterone (DHT) at 10(-7)M, and flutamide (FLU) at 10(-6)M. In both genders at NF 58 and 66, T and DHT decreased luteinizing hormone beta (lhβ), but increased follicle stimulating hormone beta (fshβ), while FLU induced lhβ specifically in males. In the testis steroidogenic genes (p450 side chain cleavage enzyme, p450scc; steroid acute regulatory protein, star) at NF 58 showed a similar pattern as for lhβ, while the response at NF 66 was only partially present. In females, TAM induced lhβ at NF 58, while E2 decreased lhβ and increased fshβ at NF 66. In the ovaries, no alterations were observed for the steroidogenic genes. Summarizing, gonadotropic and steroidogenic mRNA expression may indicate control of androgen level during testis differentiation in male tadpoles at NF 58. In females the non-responsiveness of steroidogenic genes could be a sign of gonadal quiescence during pre-pubertal stages.
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Affiliation(s)
- Ralph Urbatzka
- CIIMAR, Centre of Marine and Environmental Research, Laboratory of Ecotoxicology, Genomics and Evolution, Rua dos Bragas 289, 4050-123 Porto, Portugal.
| | - Claudia Lorenz
- Department of Ecophysiology and Aquaculture, Leibniz-Institute for Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587 Berlin, Germany
| | - Caterina Wiedemann
- Reproduction Biology, Leibniz-Institute for Zoo and Wildlife Research, PF 601103, 10252 Berlin, Germany
| | - Ilka Lutz
- Department of Ecophysiology and Aquaculture, Leibniz-Institute for Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587 Berlin, Germany
| | - Werner Kloas
- Department of Ecophysiology and Aquaculture, Leibniz-Institute for Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587 Berlin, Germany; Department of Endocrinology, Institute of Biology, Humboldt-University, Berlin, Germany
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