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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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Womack MC, Steigerwald E, Blackburn DC, Cannatella DC, Catenazzi A, Che J, Koo MS, McGuire JA, Ron SR, Spencer CL, Vredenburg VT, Tarvin RD. State of the Amphibia 2020: A Review of Five Years of Amphibian Research and Existing Resources. ICHTHYOLOGY & HERPETOLOGY 2022. [DOI: 10.1643/h2022005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Molly C. Womack
- Department of Biology, Utah State University, Logan, Utah 84322; . ORCID: 0000-0002-3346-021X
| | - Emma Steigerwald
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California 94720; (ES) ; (MSK) ; (JAM) ; (CS) ; (VTV) ; and (RDT)
| | - David C. Blackburn
- Department of Natural History, Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611; . ORCID: 0000-0002-1810-9886
| | - David C. Cannatella
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas 78712; . ORCID: 0000-0001-8675-0520
| | | | - Jing Che
- State Key Laboratory of Genetic Resources and Evolution & Yunnan Key Laboratory of Biodiversity and Ecological Security of Gaoligong Mountain, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China; . ORCID: 0000-0003-4246-6
| | - Michelle S. Koo
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California 94720; (ES) ; (MSK) ; (JAM) ; (CS) ; (VTV) ; and (RDT)
| | - Jimmy A. McGuire
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California 94720; (ES) ; (MSK) ; (JAM) ; (CS) ; (VTV) ; and (RDT)
| | - Santiago R. Ron
- Museo de Zoología, Escuela de Biología, Pontificia Universidad Católica del Ecuador, Quito, Ecuador; . ORCID: 0000-0001-6300-9350
| | - Carol L. Spencer
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California 94720; (ES) ; (MSK) ; (JAM) ; (CS) ; (VTV) ; and (RDT)
| | - Vance T. Vredenburg
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California 94720; (ES) ; (MSK) ; (JAM) ; (CS) ; (VTV) ; and (RDT)
| | - Rebecca D. Tarvin
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California 94720; (ES) ; (MSK) ; (JAM) ; (CS) ; (VTV) ; and (RDT)
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3
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Zeitler EF, Cecala KK, McGrath DA. Carryover effects minimized the positive effects of treated wastewater on anuran development. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 289:112571. [PMID: 33866133 DOI: 10.1016/j.jenvman.2021.112571] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 03/26/2021] [Accepted: 04/05/2021] [Indexed: 06/12/2023]
Abstract
Constructed wetlands (CWs) are a potential solution for wastewater treatment due to their capacity to support native species and provide tertiary wastewater treatment. However, CWs can expose wildlife communities to excess nutrients and harmful contaminants, affecting their development, morphology, and behavior. To examine how wastewater CWs may affect wildlife, we raised Southern leopard frogs, Lithobates sphenocephalus, in wastewater from conventional secondary lagoon and tertiary CW treatments for comparison with pondwater along with the presence and absence of a common plant invader to these systems - common duckweed (Lemna minor) - and monitored their juvenile development for potential carryover effects into the terrestrial environment. The tertiary CW treatment did not change demographic or morphological outcomes relative to conventional wastewater treatment in our study. Individuals emerging from both wastewater treatments demonstrated lower terrestrial survival rates than those emerging from pondwater throughout the experiment though experiment-wide survival rates were equivalent among treatments. Individuals from wastewater treatments transformed at larger sizes relative to those in pondwater, but this advantage was minimized in the terrestrial environment. Individuals that developed with duckweed had consistent but marginally better performance in both environments. Our results suggest a potential trade-off between short-term benefits of development in treated effluent and long-term consequences on overall fitness. Overall, we demonstrate that CWs for the purpose of wastewater treatment may not be suitable replicates for wildlife habitat and could have consequences for local population dynamics.
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Affiliation(s)
- Emma F Zeitler
- Department of Biology, University of the South, Sewanee, TN, 37383, USA
| | - Kristen K Cecala
- Department of Biology, University of the South, Sewanee, TN, 37383, USA.
| | - Deborah A McGrath
- Department of Biology, University of the South, Sewanee, TN, 37383, USA
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4
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Jacobs LE, Hammond TT, Gaffney PM, Curtis MJ, Shier DM, Durrant BS, Righton A, Williams CL, Calatayud NE. Using reproductive technologies to assess the development of secondary sexual characteristics, ovarian senescence and hermaphroditism in the endangered mountain yellow-legged frog Rana muscosa. Reprod Fertil Dev 2021; 33:610-614. [PMID: 34148562 DOI: 10.1071/rd21029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 05/26/2021] [Indexed: 11/23/2022] Open
Abstract
Anurans can display a host of intriguing sexual syndromes, including hermaphroditism and sex reversal. Using a multifaceted approach for diagnosing and characterising hermaphroditism in the endangered anuran species Rana mucosa , we tracked changes in female reproductive status using hormone monitoring, ultrasound examinations, individual life history, fertilisation records and post-mortem findings. Seven individuals originally sexed as females developed secondary male sexual characteristics, behaviour and hormone profiles and, in some cases, had testicular tissue despite having previously laid eggs. Our results suggest that reproductive technologies can shed light on life history patterns and reproductive anomalies that may affect endangered anuran survival.
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Affiliation(s)
- Leah E Jacobs
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92025, USA; and Corresponding author
| | - Talisin T Hammond
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92025, USA
| | - Patricia M Gaffney
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92025, USA
| | - Michelle J Curtis
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92025, USA
| | - Debra M Shier
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92025, USA
| | - Barbara S Durrant
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92025, USA
| | - Alison Righton
- Omaha's Henry Doorly Zoo and Aquarium, 3701 S 10th Street Omaha, NE 68107, USA
| | - Candace L Williams
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92025, USA
| | - Natalie E Calatayud
- San Diego Zoo Wildlife Alliance, Beckman Center for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92025, USA; and Conservation Science Network, 24 Thomas Street, Mayfield, NSW 2304, Australia
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5
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Windle S, McMurry S, Brain R, Maul J, Pickford DB, Wolf J, Belden J. Evaluating a developmental endocrine toxicity assay for Blanchard's cricket frog (Acris blanchardi) in outdoor enclosures. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 767:145444. [PMID: 33636781 DOI: 10.1016/j.scitotenv.2021.145444] [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: 11/20/2020] [Revised: 01/22/2021] [Accepted: 01/23/2021] [Indexed: 06/12/2023]
Abstract
A developmental toxicity testing design was evaluated for larval and post-metamorphic Blanchard's cricket frogs (Acris blanchardi) raised in outdoor enclosures. Larvae were chronically exposed to 17β-estradiol (0.0-2.3 μg/L E2) from free swimming (Gosner stage 26) until metamorphosis. Juvenile frogs were allowed to mature within the enclosures for 60 days to assess effects of larval exposure on development, including body mass, snout-vent length (SVL), sex ratio, gonad size, and gonadal histopathology. Forty-eight percent of the initial 600 animals were recovered at the end of the study. Recovery was not influenced by E2 exposure, but larval losses were negatively impacted by unusually high spring rain events that flooded some larval tanks, and heat-related mortality of late stage larvae during summer. All surviving larvae completed metamorphosis within an average of 47 days. Overall, E2 exposure did not influence sex ratio, or the body mass, SVL, or gonad size of either males or females. Development of testes was not influenced by E2 exposure, but oviduct development in males was 4.5-fold greater in the highest treatment. Oviduct and ovary development in females exposed to the two highest E2 treatments were half that of control females. Although not treatment related and despite ad-lib feeding, variation in terminal body mass and SVL within enclosures was pronounced, with minimum - maximum differences ranging from 207 to 1442 mg for body mass and 1 mm to 15 mm for SVL. This design allowed us to assess the effects of larval exposure to a contaminant on post-metamorphic development of a native amphibian in a semirealistic field environment. With modifications to decrease flooding or overheating, this enclosure design and species is a good test system for assessing contaminant effects on development of an amphibian from early larval stages through reproductive maturity.
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Affiliation(s)
- Shauni Windle
- Department of Integrative Biology, Oklahoma State University, United States of America.
| | - Scott McMurry
- Department of Integrative Biology, Oklahoma State University, United States of America
| | - Richard Brain
- Syngenta Crop Protection LLC., Greensboro, NC, United States of America
| | - Jonathan Maul
- Syngenta Crop Protection LLC., Greensboro, NC, United States of America
| | - Daniel B Pickford
- Syngenta Crop Protection Ltd., Jealott's Hill International Research Centre, UK
| | - Jeffrey Wolf
- Experimental Pathology Laboratories, Inc., Sterling, VA, United States of America
| | - Jason Belden
- Department of Integrative Biology, Oklahoma State University, United States of America
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6
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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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7
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Hoskins TD, Dellapina M, Papoulias DM, Boone MD. Effects of larval atrazine exposure in mesocosms on Blanchard's cricket frogs (Acris blanchardi) reared through overwintering and to reproductive age. CHEMOSPHERE 2019; 220:845-857. [PMID: 33395806 DOI: 10.1016/j.chemosphere.2018.12.112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 12/14/2018] [Accepted: 12/15/2018] [Indexed: 06/12/2023]
Abstract
We exposed Blanchard's cricket frog (Acris blanchardi) tadpoles to atrazine in simulated aquatic communities (outdoor mesocosms) at nominal concentrations of 0, 1, 10, 100, and 200 μg/L and tracked the effects of exposure to spring emergence in the laboratory, as well as to reproductive age in outdoor, terrestrial enclosures. We tested hypotheses that 1) atrazine addition increases the prevalence and intensity of testicular ova (TO) among phenotypic males at metamorphosis and after overwintering, 2) atrazine reduces maturation of ova after overwintering among phenotypic females, and 3) atrazine alters mass, time, and survival to metamorphosis, as well as growth and survival across terrestrial life stages. Atrazine addition increased probability of TO presence at metamorphosis, but only when treatments were pooled and compared to the control, where background atrazine was detected. Atrazine did not influence the intensity of TO among metamorphs. We observed TO among males at spring emergence and at reproductive age regardless of exposure concentration. We found no evidence for effects of exposure on gonadal maturation among females after overwintering. Exposure to 200 μg/L reduced survival to metamorphosis, but atrazine did not affect mass at metamorphosis, time to metamorphosis, or survival or mass after overwintering. We demonstrate that atrazine addition can increase TO prevalence relative to background rates at metamorphosis and that TO are also present among phenotypic males after overwintering. We suggest that this non-model species is sensitive to effects of larval EDC exposures on gonadal development and morphology and that further work with cricket frogs is warranted.
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8
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Lambert MR, Smylie MS, Roman AJ, Freidenburg LK, Skelly DK. Sexual and somatic development of wood frog tadpoles along a thermal gradient. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 329:72-79. [PMID: 29791087 DOI: 10.1002/jez.2172] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 04/27/2018] [Indexed: 01/23/2023]
Abstract
All amphibian species are known to have genetic sex determination. However, a variety of environmental conditions can moderate sexual differentiation, in some cases leading to sex reversal and skewed sex ratios. While there has been a recent focus on chemically-induced sex reversal in amphibians, temperature can also influence sexual differentiation. Building upon a classic 1929 study by Emil Witschi, we assessed temperature-mediated sex reversal. Witschi found that the wood frog sex ratio is 100% male at a high temperature (32°C) compared to a 50:50 sex ratio at 20°C. This pattern is consistent with multiple models of environmentally mediated sexual differentiation in vertebrates. To better understand thermally mediated sex reversal, we raised wood frogs at temperature increments of ∼1°C between 19 and 34°C. Mirroring earlier findings, wood frog metamorph sex ratios are indistinguishable from 50:50 at the lowest temperature and entirely male at the highest temperatures. In between, sex ratios become increasingly male-dominated as temperatures increase, implying a steadily increasing tendency toward female-to-male sex reversal in warmer environments. There was no evidence of a threshold temperature effect on reversal patterns. We also show that, compared to males, females metamorphose larger and later in cooler conditions but earlier and smaller under warmer conditions. While the ecological relevance in this species is unknown, these results conform to the Charnov-Bull model of sex determination (in which female-to-male sex reversal can increase fitness to genetic females at higher temperatures), suggesting the system would reward further study.
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Affiliation(s)
- Max R Lambert
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut
| | - Meredith S Smylie
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut
| | - Amber J Roman
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut
| | - L Kealoha Freidenburg
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut
| | - David K Skelly
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut
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9
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Hoskins TD, Boone MD. Atrazine feminizes sex ratio in Blanchard's cricket frogs (Acris blanchardi) at concentrations as low as 0.1 μg/L. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2018; 37:427-435. [PMID: 29028124 DOI: 10.1002/etc.3962] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/14/2017] [Accepted: 08/22/2017] [Indexed: 06/07/2023]
Abstract
We exposed Blanchard's cricket frogs (Acris blanchardi) to ecologically relevant concentrations (0, 0.1, 1, and 10 μg/L) of a commercial formulation of atrazine throughout the larval period to determine effects on survival, somatic growth and development (time to metamorphosis and mass at metamorphosis), and gonadal development (sex ratio at metamorphosis and the prevalence of testicular ova in phenotypic males). We tested the following hypotheses: 1) atrazine feminizes the sex ratio, 2) atrazine increases the proportion of phenotypic males with testicular ova, and 3) atrazine differentially affects somatic growth (mass at metamorphosis) and development (time to metamorphosis) for males and females. Although the control sex ratio was male-biased, exposure to 0.1 and 10 μg/L atrazine feminized sex ratios, because these treatments produced 51 and 55% fewer males than the control, respectively. We did not observe testicular ova. Atrazine did not impact survival or metamorphosis, and we did not detect sexually dimorphic impacts on time to metamorphosis or mass at metamorphosis. However, males metamorphosed 2.3 d later than females, regardless of treatment. Sex biases in timing of metamorphosis are underexplored in anurans, but if prevalent, could have important implications for theory surrounding the impact of environmental factors on metamorphosis. Our data suggest that cricket frog sex ratios are sensitive to environmentally relevant concentrations of atrazine and that feminization in the field is likely. Environ Toxicol Chem 2018;37:427-435. © 2017 SETAC.
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Hoskins TD, Dellapina M, Boone MD. Short-term atrazine exposure at breeding has no impact on Blanchard's cricket frog (Acris blanchardi) reproductive success. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2017; 36:3284-3288. [PMID: 28657116 DOI: 10.1002/etc.3900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/29/2017] [Accepted: 06/26/2017] [Indexed: 06/07/2023]
Abstract
Studies of endocrine-disrupting contaminants have focused on early-life exposures, but later exposures could impact fitness. We exposed adult frogs (Acris blanchardi) at reproduction to ecologically relevant atrazine concentrations (0, 1, or 10 µg/L) in outdoor arenas. We measured likelihood of breeding and number of resulting tadpoles. Atrazine impacted neither the probability of breeding nor the number of tadpoles produced, suggesting anuran reproductive success may not be impacted by short-term exposure to low concentrations. Environ Toxicol Chem 2017;36:3284-3288. © 2017 SETAC.
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11
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Matthiessen P, Wheeler JR, Weltje L. A review of the evidence for endocrine disrupting effects of current-use chemicals on wildlife populations. Crit Rev Toxicol 2017; 48:195-216. [DOI: 10.1080/10408444.2017.1397099] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
| | | | - Lennart Weltje
- BASF SE, Crop Protection – Ecotoxicology, Limburgerhof, Germany
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12
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Hoskins TD, Boone MD. Variation in malathion sensitivity among populations of Blanchard's cricket frogs (Acris blanchardi) and implications for risk assessment. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2017; 36:1917-1923. [PMID: 27982495 DOI: 10.1002/etc.3715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 06/14/2016] [Accepted: 12/13/2016] [Indexed: 06/06/2023]
Abstract
Intraspecific variability in contaminant sensitivity could undermine risk assessments for nontarget organisms such as amphibians. To test how amphibian populations vary in tolerance to anticipated lethal and sublethal exposures to a pesticide, we exposed Blanchard's cricket frogs (Acris blanchardi) from 3 populations across a broad portion of their range to the insecticide malathion. Exposure in mesocosms to a nominal concentration of 1 mg/L (measured concentrations at 1 h and 24 h postaddition of 0.160 mg/L and 0.062 mg/L, respectively), a realistic direct-overspray scenario, reduced survival to metamorphosis by 43% relative to controls and revealed variation in tolerance among populations. Survival ranged from 74% for the most tolerant population to 18% for the least tolerant population, a 4.1-fold difference. Mass at metamorphosis and time to metamorphosis were unaffected. Although malathion reduced zooplankton abundance, it did not alter food resources (periphyton or phytoplankton relative abundance), or a suite of water-quality variables (pH, temperature, and dissolved oxygen). A 96-h time-to-death assay designed to isolate direct, lethal effects also revealed variation in tolerance among populations. Time to death (mean ± standard error) ranged from 2.4 ± 0.18 h for the least tolerant population to 17.8 ± 4.72 h for the most tolerant population, a 7.4-fold difference. However, relative sensitivities of populations differed in the mesocosm and laboratory studies, which differed in exposure concentrations, suggesting that populations tolerant of high concentrations can be more sensitive to lower concentrations. We suggest that direct overspray could reduce larval survival in the field for this species. Studies assessing the role of contaminants in declines or extrapolating to untested populations, especially across large geographical regions, should quantify the range of intraspecific variation. Risk assessors could address intraspecific variability directly by using an intraspecific uncertainty factor. Environ Toxicol Chem 2017;36:1917-1923. © 2016 SETAC.
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13
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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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14
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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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15
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Abstract
PURPOSE To study the adverse impacts of ultraviolet radiation-A (UVA 320-400 nm) on some hematological and biochemical parameters of Bufo regularis was considered. MATERIALS AND METHODS Samples were classified into four groups: (i) Control; (ii) ultraviolet radiation (UVR)-treated group (for 3 days/for 15 min/day); (iii) UVR-treated group (for 3 days/for 30 min/day); and (iv) (for 3 days/for 60 min/day). The destructive effects of UVA radiation was evaluated by red blood cells (RBC) count, hemoglobin content (Hb), hematocrite (Ht), erythrocytic indices, white blood cells (WBC) count, total protein, glucose, aspartic amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP), lactate dehyderogenase (LDH), glucose-6-phosphate dehyderogenase (G6PDH) and total bilribuin. RESULTS No mortality was observed. However, some physiological effects after the exposure to UVA were reported. The UVA-induced malformations recorded in the red blood cells included crenated cells (Cr), Acanthocytes (Ac), tear drop-like cells (Tr) and sickle cells (Sk). CONCLUSION The present study revealed the exposure to UVA from 15-60 min/day for three days could promote several biochemical and physiological disturbances as well as some changes in RBC.
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Affiliation(s)
- Alaa El-Din H Sayed
- a Zoology Department , Faculty of Science, Assiut University , Assiut , Egypt
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16
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Douglas HD, Malenke JR. An Extraordinary Host-Specific Sex Ratio in an Avian Louse (Phthiraptera: Insecta)--Chemical Distortion? ENVIRONMENTAL ENTOMOLOGY 2015; 44:1149-1154. [PMID: 26314060 DOI: 10.1093/ee/nvv073] [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: 11/09/2014] [Accepted: 04/20/2015] [Indexed: 06/04/2023]
Abstract
Distortions of sex ratios and sexual traits from synthetic chemicals have been well documented; however, there is little evidence for such phenomena associated with naturally occurring chemical exposures. We reasoned that chemical secretions of vertebrates could contribute to skewed sex ratios in ectoparasitic insects due to differences in susceptibility among the sexes. For example, among ectoparasitic lice the female is generally the larger sex. Smaller males may be more susceptible to chemical effects. We studied sex ratios of lice on two sympatric species of colonial seabirds. Crested auklets (Aethia cristatella) secrete a strong smelling citrus-like odorant composed of aldehydes while a closely related congener the least auklet (Aethia pusilla) lacks these compounds. Each auklet hosts three species of lice, two of which are shared in common. We found that the sex ratio of one louse species, Quadraceps aethereus (Giebel), was highly skewed on crested auklets 1:69 (males: females), yet close to unity on least auklets (1:0.97). We suggest that a host-specific effect contributes to this difference, such as the crested auklet's chemical odorant.
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Affiliation(s)
- H D Douglas
- Institute of Marine Science, University of Alaska, Fairbanks, AK 99775. Current address: Science Department, College of Rural and Community Development, Kuskokwim Campus, University of Alaska, Bethel, AK 99559.
| | - J R Malenke
- Department of Biology, University of Utah, Salt Lake City, UT 84412
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17
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Abdel-moneim A, Coulter DP, Mahapatra CT, Sepúlveda MS. Intersex in fishes and amphibians: population implications, prevalence, mechanisms and molecular biomarkers. J Appl Toxicol 2015. [PMID: 26211897 DOI: 10.1002/jat.3204] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ahmed Abdel-moneim
- Department of Forestry and Natural Resources; Purdue University; West Lafayette IN 47907 USA
- Department of Veterinary Forensic Medicine & Toxicology; Assiut University; Assiut 71526 Egypt
| | - David P. Coulter
- Department of Forestry and Natural Resources; Purdue University; West Lafayette IN 47907 USA
| | - Cecon T. Mahapatra
- Department of Forestry and Natural Resources; Purdue University; West Lafayette IN 47907 USA
| | - Maria S. Sepúlveda
- Department of Forestry and Natural Resources; Purdue University; West Lafayette IN 47907 USA
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18
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Van Der Kraak GJ, Hosmer AJ, Hanson ML, Kloas W, Solomon KR. Effects of atrazine in fish, amphibians, and reptiles: an analysis based on quantitative weight of evidence. Crit Rev Toxicol 2015; 44 Suppl 5:1-66. [PMID: 25375889 DOI: 10.3109/10408444.2014.967836] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A quantitative weight of evidence (WoE) approach was developed to evaluate studies used for regulatory purposes, as well as those in the open literature, that report the effects of the herbicide atrazine on fish, amphibians, and reptiles. The methodology for WoE analysis incorporated a detailed assessment of the relevance of the responses observed to apical endpoints directly related to survival, growth, development, and reproduction, as well as the strength and appropriateness of the experimental methods employed. Numerical scores were assigned for strength and relevance. The means of the scores for relevance and strength were then used to summarize and weigh the evidence for atrazine contributing to ecologically significant responses in the organisms of interest. The summary was presented graphically in a two-dimensional graph which showed the distributions of all the reports for a response. Over 1290 individual responses from studies in 31 species of fish, 32 amphibians, and 8 reptiles were evaluated. Overall, the WoE showed that atrazine might affect biomarker-type responses, such as expression of genes and/or associated proteins, concentrations of hormones, and biochemical processes (e.g. induction of detoxification responses), at concentrations sometimes found in the environment. However, these effects were not translated to adverse outcomes in terms of apical endpoints. The WoE approach provided a quantitative, transparent, reproducible, and robust framework that can be used to assist the decision-making process when assessing environmental chemicals. In addition, the process allowed easy identification of uncertainty and inconsistency in observations, and thus clearly identified areas where future investigations can be best directed.
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19
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Haselman JT, Olmstead AW, Degitz SJ. Global gene expression during early differentiation of Xenopus (Silurana) tropicalis gonad tissues. Gen Comp Endocrinol 2015; 214:103-13. [PMID: 24960269 DOI: 10.1016/j.ygcen.2014.06.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 05/21/2014] [Accepted: 06/12/2014] [Indexed: 01/04/2023]
Abstract
African clawed frog Xenopus sp. is used extensively for developmental biology and toxicology research. Amid concerns of environmental pollutants disrupting endocrine systems and causing altered reproductive development in wildlife, eco-toxicology research has led to a focus on linking molecular initiating events to population-level effects. As such, efforts to better understand reproductive development at the molecular level in these model species are warranted. To that end, transcriptomes were characterized in differentiating Xenopus tropicalis gonad tissues at Nieuwkoop and Faber (NF) stage 58 (pro-metamorphosis), NF66 (completion of metamorphosis), 1week post-metamorphosis (1WPM), and 2weeks post-metamorphosis (2WPM). Differential expression analysis between tissue types at each developmental stage revealed a substantial divergence of ovary and testis transcriptomes starting between NF58 and NF66; transcriptomes continued to diverge through 2WPM. Generally, testis-enriched transcripts were expressed at relatively constant levels, while ovary-enriched transcripts were up-regulated within this developmental period. Functional analyses of differentially expressed transcripts allowed linkages to be made between their putative human orthologues and specific cellular processes associated with differentiating gonad tissues. In ovary tissue, genetic programs direct germ cells through meiosis to the diplotene stage when maternal mRNAs are transcribed and trafficked to oocytes for translation following fertilization. In the testis, gene expression is consistent with connective tissue development, tubule formation, and germ cell support (Leydig and Sertoli cells). This dataset exhibited remarkable consistency with transcript profiles previously described in gonad tissues across species, and emphasizes the universal importance of certain transcripts for germ cell development and preparation of these tissues for reproduction.
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Affiliation(s)
- Jonathan T Haselman
- US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA.
| | - Allen W Olmstead
- US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA.
| | - Sigmund J Degitz
- US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA.
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20
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Kobayashi T, Kumakura M, Yoshie S, Sugishima T, Horie Y. Dynamics of testis-ova in a wild population of Japanese pond frogs,Rana nigromaculata. ACTA ACUST UNITED AC 2014; 323:74-9. [DOI: 10.1002/jez.1898] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Revised: 09/03/2014] [Accepted: 09/06/2014] [Indexed: 11/10/2022]
Affiliation(s)
- Tohru Kobayashi
- Laboratory of Molecular Reproductive Biology; Institute for Environmental Sciences; University of Shizuoka; Suruga-ku Shizuoka Japan
- Laboratory of Molecular Reproductive Biology; Graduate School of Integrated Pharmaceutical and Nutritional Sciences; University of Shizuoka; Suruga-ku Shizuoka Japan
| | - Masahiko Kumakura
- Department of Histology, School of Life Dentistry at Niigata; The Nippon Dental University; Chuo-ku Niigata Japan
| | - Sumio Yoshie
- Department of Histology, School of Life Dentistry at Niigata; The Nippon Dental University; Chuo-ku Niigata Japan
| | - Tomomi Sugishima
- Laboratory of Molecular Reproductive Biology; Institute for Environmental Sciences; University of Shizuoka; Suruga-ku Shizuoka Japan
| | - Yoshifumi Horie
- Laboratory of Molecular Reproductive Biology; Institute for Environmental Sciences; University of Shizuoka; Suruga-ku Shizuoka Japan
- Laboratory of Molecular Reproductive Biology; Graduate School of Integrated Pharmaceutical and Nutritional Sciences; University of Shizuoka; Suruga-ku Shizuoka Japan
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21
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Orton F, Tyler CR. Do hormone-modulating chemicals impact on reproduction and development of wild amphibians? Biol Rev Camb Philos Soc 2014; 90:1100-17. [DOI: 10.1111/brv.12147] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 09/01/2014] [Accepted: 09/12/2014] [Indexed: 01/17/2023]
Affiliation(s)
- Frances Orton
- Biosciences; College of Life and Environmental Sciences, University of Exeter; Stocker Road Exeter EX4 4QD U.K
| | - Charles R. Tyler
- Biosciences; College of Life and Environmental Sciences, University of Exeter; Stocker Road Exeter EX4 4QD U.K
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22
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Terasaki M, Yasuda M, Shimoi K, Jozuka K, Makino M, Shiraishi F, Nakajima D. Evaluation of sensitizers found in wastewater from paper recycling areas, and their activation of the aryl hydrocarbon receptor in vitro. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 493:156-161. [PMID: 24950494 DOI: 10.1016/j.scitotenv.2014.05.144] [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: 02/14/2014] [Revised: 05/29/2014] [Accepted: 05/30/2014] [Indexed: 06/03/2023]
Abstract
The in vitro potential of sensitizers and related compounds (SRCs) originating from impurities in waste paper in activating the human aryl hydrocarbon receptor (AhR) α was assessed using yeast reporter gene as well as cytochrome P450 (CYP)1A1 and ethoxyresorufin O-deethylase (EROD) assays. In the yeast assay, eight compounds exhibited agonist activity, and their activity relative to β-naphthoflavone (BNF) ranged from 1.4 × 10(-4) to 8.3 × 10(-2), with the highest activity observed for benzyl 2-naphthyl ether (BNE). In the EROD assay, six compounds caused a more significant induction of CYP1A-dependent activity than did the vehicle control at 50 μM (p<0.01), and their induction levels were 5.1- to 11-fold more potent; 1,2-bis(3-methylphenoxy)ethane (BME) was the most effective inducer. The water from the waste paper recycling area was fractioned using solid-phase extraction (SPE) combined with a C18 disk and florisil cartridge. In gas chromatography-mass spectrometry (GC-MS) analysis, SRCs were detected in the first fraction, at a total concentration of 5.5 μg/L. This fraction also activated AhR, and its activity, expressed as a BNF equivalent value, was 0.42 nM in the yeast assay. The contribution ratio of active compounds accounted for up to 34% and 4.4% observed activity of the fraction and total samples, respectively. To our knowledge, this is the first study to show that paper industry-related compounds, namely aromatic sensitizers, activate AhR by using a yeast assay and HepG2 cells.
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Affiliation(s)
- Masanori Terasaki
- Institute for Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
| | - Michiko Yasuda
- Institute for Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Kayoko Shimoi
- Institute for Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Kazuhiko Jozuka
- Institute for Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Masakazu Makino
- Institute for Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Fujio Shiraishi
- Research Center for Environmental Risk, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan
| | - Daisuke Nakajima
- Research Center for Environmental Risk, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan
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23
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Orton F, Baynes A, Clare F, Duffus ALJ, Larroze S, Scholze M, Garner TWJ. Body size, nuptial pad size and hormone levels: potential non-destructive biomarkers of reproductive health in wild toads (Bufo bufo). ECOTOXICOLOGY (LONDON, ENGLAND) 2014; 23:1359-1365. [PMID: 24935780 DOI: 10.1007/s10646-014-1261-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/15/2014] [Indexed: 06/03/2023]
Abstract
Amphibians are declining and fertility/fecundity are major drivers of population stability. The development of non-destructive methods to assess reproductive health are needed as destructive measures are fundamentally at odds with conservation goals for declining species. We investigated the utility of body size, nuptial pad size and forelimb width as non-destructive biomarkers of internal reproductive physiology, by analysing correlations with commonly used destructive methods in adult male toads (Bufo bufo) from a low human impact and a high human impact site. Principal component analyses revealed that size was the most important variable for explaining inter-individual differences in other measured endpoints, both non-destructive and destructive, except for hormone levels and nuptial pad, which were independent of size. Toads from the LI and the HI site differed in almost all of the measured endpoints; this was largely driven by the significantly smaller size of toads from the HI site. Correlational analyses within sites revealed that size was correlated with several reproductive endpoints in toads from the HI site but not the LI site, indicating a possible limiting effect of size on reproductive physiology. Intersex was observed in 33% of toads from the HI site and incidence was not related to any other measured endpoint. In conclusion, we provide evidence that size is associated with reproductive physiology and that nuptial pad/hormone levels have potential as additional markers due to their independence from size. We also show that human activities can have a negative effect on reproductive physiology of the common toad.
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Affiliation(s)
- Frances Orton
- Biosciences, School of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK,
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24
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Moresco RM, Margarido VP, de Oliveira C. A persistent organic pollutant related with unusual high frequency of hermaphroditism in the neotropical anuran Physalaemus cuvieri Fitzinger, 1826. ENVIRONMENTAL RESEARCH 2014; 132:6-11. [PMID: 24742721 DOI: 10.1016/j.envres.2014.03.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 01/07/2014] [Accepted: 03/12/2014] [Indexed: 06/03/2023]
Abstract
Representing a reflection of anthropic activity, the level of xenobiotic compounds in aquatic ecosystems has increased in recent years, bringing severe damage to the environment. The present work reports the occurrence of malformation in gonads of Physalaemus cuvieri individuals from a population of Atlantic Forest in Southern Brazil. Twenty male specimens were collected, which had their testicles removed, immersed in Karnovsky fixative solution, included in historesin for 2 μm cuts and stained with Hematoxylin-eosin. Four specimens showed intersexual gonads condition along with the presence of sperm and oocytes. In order to test a possible contamination of water, 2L were collected from the water body to check organochlorine, organophosphate and carbamate compounds. The analysis of water showed the presence of agrotoxic Dieldrin in a concentration of 0.05 μg/L, representing a concentration above the recommended reference. This agrotoxic, in addition to acting as endocrine disrupter and commercially prohibited, has quite persistent residual effects, and may be responsible for the high frequency of P. cuvieri with intersexual gonads, which in the long term can represent a risk for this population due to the potential impact on its effective reproductive ability.
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Affiliation(s)
- Rafaela M Moresco
- Universidade Estadual Paulista (Unesp), Departamento de Biologia. Rua Cristóvão Colombo, 2265-Jardim Nazareth, CEP 15054-000, São José do Rio Preto, São Paulo, Brazil; Universidade Estadual do Oeste do Paraná (Unioeste), Centro de Ciências Biológicas e da Saúde, Rua Universitária, 2069-Jardim Universitário, CEP 85819-110, Cascavel, Paraná, Brazil.
| | - Vladimir P Margarido
- Universidade Estadual do Oeste do Paraná (Unioeste), Centro de Ciências Biológicas e da Saúde, Rua Universitária, 2069-Jardim Universitário, CEP 85819-110, Cascavel, Paraná, Brazil
| | - Classius de Oliveira
- Universidade Estadual Paulista (Unesp), Departamento de Biologia. Rua Cristóvão Colombo, 2265-Jardim Nazareth, CEP 15054-000, São José do Rio Preto, São Paulo, Brazil
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25
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Vandenberg LN, Colborn T, Hayes TB, Heindel JJ, Jacobs DR, Lee DH, Shioda T, Soto AM, vom Saal FS, Welshons WV, Zoeller RT, Myers JP. Hormones and endocrine-disrupting chemicals: low-dose effects and nonmonotonic dose responses. Endocr Rev 2012; 33:378-455. [PMID: 22419778 PMCID: PMC3365860 DOI: 10.1210/er.2011-1050] [Citation(s) in RCA: 2007] [Impact Index Per Article: 167.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 02/07/2012] [Indexed: 02/08/2023]
Abstract
For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of "the dose makes the poison," because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from the cell culture, animal, and epidemiology literature. We illustrate that nonmonotonic responses and low-dose effects are remarkably common in studies of natural hormones and EDCs. Whether low doses of EDCs influence certain human disorders is no longer conjecture, because epidemiological studies show that environmental exposures to EDCs are associated with human diseases and disabilities. We conclude that when nonmonotonic dose-response curves occur, the effects of low doses cannot be predicted by the effects observed at high doses. Thus, fundamental changes in chemical testing and safety determination are needed to protect human health.
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Affiliation(s)
- Laura N Vandenberg
- Tufts University, Center for Regenerative and Developmental Biology, Department of Biology, 200 Boston Avenue, Suite 4600, Medford, Massachusetts 02155, USA.
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26
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Säfholm M, Norder A, Fick J, Berg C. Disrupted Oogenesis in the Frog Xenopus tropicalis after Exposure to Environmental Progestin Concentrations1. Biol Reprod 2012; 86:126. [DOI: 10.1095/biolreprod.111.097378] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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27
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Hayes TB, Anderson LL, Beasley VR, de Solla SR, Iguchi T, Ingraham H, Kestemont P, Kniewald J, Kniewald Z, Langlois VS, Luque EH, McCoy KA, Muñoz-de-Toro M, Oka T, Oliveira CA, Orton F, Ruby S, Suzawa M, Tavera-Mendoza LE, Trudeau VL, Victor-Costa AB, Willingham E. Demasculinization and feminization of male gonads by atrazine: consistent effects across vertebrate classes. J Steroid Biochem Mol Biol 2011; 127:64-73. [PMID: 21419222 PMCID: PMC4303243 DOI: 10.1016/j.jsbmb.2011.03.015] [Citation(s) in RCA: 209] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 02/08/2011] [Accepted: 03/04/2011] [Indexed: 12/20/2022]
Abstract
Atrazine is the most commonly detected pesticide contaminant of ground water, surface water, and precipitation. Atrazine is also an endocrine disruptor that, among other effects, alters male reproductive tissues when animals are exposed during development. Here, we apply the nine so-called "Hill criteria" (Strength, Consistency, Specificity, Temporality, Biological Gradient, Plausibility, Coherence, Experiment, and Analogy) for establishing cause-effect relationships to examine the evidence for atrazine as an endocrine disruptor that demasculinizes and feminizes the gonads of male vertebrates. We present experimental evidence that the effects of atrazine on male development are consistent across all vertebrate classes examined and we present a state of the art summary of the mechanisms by which atrazine acts as an endocrine disruptor to produce these effects. Atrazine demasculinizes male gonads producing testicular lesions associated with reduced germ cell numbers in teleost fish, amphibians, reptiles, and mammals, and induces partial and/or complete feminization in fish, amphibians, and reptiles. These effects are strong (statistically significant), consistent across vertebrate classes, and specific. Reductions in androgen levels and the induction of estrogen synthesis - demonstrated in fish, amphibians, reptiles, and mammals - represent plausible and coherent mechanisms that explain these effects. Biological gradients are observed in several of the cited studies, although threshold doses and patterns vary among species. Given that the effects on the male gonads described in all of these experimental studies occurred only after atrazine exposure, temporality is also met here. Thus the case for atrazine as an endocrine disruptor that demasculinizes and feminizes male vertebrates meets all nine of the "Hill criteria".
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Affiliation(s)
- Tyrone B Hayes
- Laboratory for Integrative Studies in Amphibian Biology, Molecular Toxicology, Museum of Vertebrate Zoology, and Department of Integrative Biology, University of California, Berkeley, CA 94720, USA.
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Simulation and quantification of the natural decay of a typical endocrine disrupting chemical Atrazine in an aquatic system. JOURNAL OF HAZARDOUS MATERIALS 2011; 192:1260-6. [PMID: 21741767 DOI: 10.1016/j.jhazmat.2011.06.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 05/24/2011] [Accepted: 06/14/2011] [Indexed: 12/07/2022]
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30
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Bernabò I, Gallo L, Sperone E, Tripepi S, Brunelli E. Survival, development, and gonadal differentiation in Rana dalmatina chronically exposed to chlorpyrifos. ACTA ACUST UNITED AC 2011; 315:314-27. [DOI: 10.1002/jez.678] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 01/10/2011] [Accepted: 02/01/2011] [Indexed: 11/08/2022]
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31
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Hermelink B, Urbatzka R, Wiegand C, Pflugmacher S, Lutz I, Kloas W. Aqueous leaf extracts display endocrine activities in vitro and disrupt sexual differentiation of male Xenopus laevis tadpoles in vivo. Gen Comp Endocrinol 2010; 168:245-55. [PMID: 20226786 DOI: 10.1016/j.ygcen.2010.03.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2009] [Revised: 03/01/2010] [Accepted: 03/08/2010] [Indexed: 12/26/2022]
Abstract
The occurrence of natural substances acting as endocrine disrupting compounds (EDC) in the environment is to date poorly understood. Therefore, (anti)androgenic and (anti)estrogenic activities of three different aqueous leaf extracts (beech, reed and oak) were analyzed in vitro using yeast androgen and estrogen screen. The most potent extract was selected for in vivo exposure of Xenopus laevis tadpoles to analyze the potential effects on development and reproductive biology of amphibians. Tadpoles were exposed from stage 48 to stage 66 (end of metamorphosis) to aqueous oak leaf extracts covering natural occurring environmental concentrations of dissolved organic carbon. Gene expression analyses of selected genes of the hypothalamus-pituitary-gonad and of the hypothalamus-pituitary-thyroid axis as well as histological investigation of gonads and thyroid glands were used to evaluate endocrine disrupting effects on the reproductive biology and development. Female tadpoles remained unaffected by the exposure whereas males showed severe significant histological alterations of testes at the two highest oak leaf extract concentrations demonstrated by the occurrence of lacunae and oogonia. In addition, a significant elevation of luteinizing hormone beta mRNA expression with increasing extract concentration in male tadpoles indicates an involvement of hypothalamus-pituitary-gonad axis mainly via antiandrogenic activity. These results suggest that antiandrogenic EDC of oak leaf extract are responsible for inducing the observed effects in male tadpoles. The present study demonstrates for the first time that in surface waters, natural occurring oak leaf compounds at environmentally relevant concentrations display antiandrogenic activities and have considerable effects on the endocrine system of anurans affecting sexual differentiation of male tadpoles.
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Affiliation(s)
- Björn Hermelink
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, D-12587 Berlin, Germany.
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Atrazine induces complete feminization and chemical castration in male African clawed frogs (Xenopus laevis). Proc Natl Acad Sci U S A 2010; 107:4612-7. [PMID: 20194757 DOI: 10.1073/pnas.0909519107] [Citation(s) in RCA: 315] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The herbicide atrazine is one of the most commonly applied pesticides in the world. As a result, atrazine is the most commonly detected pesticide contaminant of ground, surface, and drinking water. Atrazine is also a potent endocrine disruptor that is active at low, ecologically relevant concentrations. Previous studies showed that atrazine adversely affects amphibian larval development. The present study demonstrates the reproductive consequences of atrazine exposure in adult amphibians. Atrazine-exposed males were both demasculinized (chemically castrated) and completely feminized as adults. Ten percent of the exposed genetic males developed into functional females that copulated with unexposed males and produced viable eggs. Atrazine-exposed males suffered from depressed testosterone, decreased breeding gland size, demasculinized/feminized laryngeal development, suppressed mating behavior, reduced spermatogenesis, and decreased fertility. These data are consistent with effects of atrazine observed in other vertebrate classes. The present findings exemplify the role that atrazine and other endocrine-disrupting pesticides likely play in global amphibian declines.
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Rohr JR, McCoy KA. A qualitative meta-analysis reveals consistent effects of atrazine on freshwater fish and amphibians. ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:20-32. [PMID: 20056568 PMCID: PMC2831963 DOI: 10.1289/ehp.0901164] [Citation(s) in RCA: 203] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Accepted: 09/23/2009] [Indexed: 05/18/2023]
Abstract
OBJECTIVE The biological effects of the herbicide atrazine on freshwater vertebrates are highly controversial. In an effort to resolve the controversy, we conducted a qualitative meta-analysis on the effects of ecologically relevant atrazine concentrations on amphibian and fish survival, behavior, metamorphic traits, infections, and immune, endocrine, and reproductive systems. DATA SOURCES We used published, peer-reviewed research and applied strict quality criteria for inclusion of studies in the meta-analysis. DATA SYNTHESIS We found little evidence that atrazine consistently caused direct mortality of fish or amphibians, but we found evidence that it can have indirect and sublethal effects. The relationship between atrazine concentration and timing of amphibian metamorphosis was regularly nonmonotonic, indicating that atrazine can both accelerate and delay metamorphosis. Atrazine reduced size at or near metamorphosis in 15 of 17 studies and 14 of 14 species. Atrazine elevated amphibian and fish activity in 12 of 13 studies, reduced antipredator behaviors in 6 of 7 studies, and reduced olfactory abilities for fish but not for amphibians. Atrazine was associated with a reduction in 33 of 43 immune function end points and with an increase in 13 of 16 infection end points. Atrazine altered at least one aspect of gonadal morphology in 7 of 10 studies and consistently affected gonadal function, altering spermatogenesis in 2 of 2 studies and sex hormone concentrations in 6 of 7 studies. Atrazine did not affect vitellogenin in 5 studies and increased aromatase in only 1 of 6 studies. Effects of atrazine on fish and amphibian reproductive success, sex ratios, gene frequencies, populations, and communities remain uncertain. CONCLUSIONS Although there is much left to learn about the effects of atrazine, we identified several consistent effects of atrazine that must be weighed against any of its benefits and the costs and benefits of alternatives to atrazine use.
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Affiliation(s)
- Jason R Rohr
- Department of Integrative Biology, University of South Florida, Tampa, Florida 33620, USA.
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Terasaki M, Shiraishi F, Fukazawa H, Makino M. Development and validation of chemical and biological analyses to determine the antiestrogenic potency of resin acids in paper mill effluents. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:9300-9305. [PMID: 20000523 DOI: 10.1021/es9025479] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This study combined chemical analysis and bioassays of paper mill effluents and their components in order to determine their antiestrogenic activity. The bioassay comprised a yeast two-hybrid assay incorporating the estrogen receptor alpha (hERalpha) and an hERalpha competitive enzyme-linked immunosorbent assay (ELISA). Samples were fractionated by solid phase extraction (SPE) with a C18 disk and a Florisil cartridge to obtain four fractions. The final fraction, eluted with methanol from the Florisil cartridge after pre-extraction by the C18 disk, was the most active in the two-hybrid assay, and its antiestrogenic potency, expressed as the equivalent concentration to 4-hydroxytamoxifen (OHT), was 277 nM. Seven resin acids had antiestrogenic activity in the active fraction as determined by gas chromatography/mass spectrometry (GC/MS), and their concentration levels ranged from 0.11 to 12 microg/L. All the resin acids exhibited greater activity than OHT; their activity relative to OHT ranged from 2.8- to 4.0-fold in the yeast two-hybrid assay. Based on the chemical analysis data and relative potency of resin acids from the yeast two-hybrid assay, the contribution ratio of resin acids accounted for 72% of the observed antiestrogenic activity of the extract. Furthermore, no resin acid showed any affinity for the estrogen receptor in the ELISA. This study showed that analysis combining the SPE method and the yeast two-hybrid assay is likely to be effective for the comprehensive monitoring of resin acids in paper mill industrial discharge areas.
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Affiliation(s)
- Masanori Terasaki
- Institute for Environmental Sciences, University of Shizuoka, Yada 52-1, Suruga-ku, Shizuoka 422-8526, Japan, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan, and Shizuoka Institute of Environment and Hygiene, 4-27-2 Kita-Ando, Aoi-ku, Shizuoka 420-8637, Japan
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Mann RM, Hyne RV, Choung CB, Wilson SP. Amphibians and agricultural chemicals: review of the risks in a complex environment. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2009; 157:2903-27. [PMID: 19500891 DOI: 10.1016/j.envpol.2009.05.015] [Citation(s) in RCA: 346] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 05/06/2009] [Accepted: 05/08/2009] [Indexed: 05/18/2023]
Abstract
Agricultural landscapes, although often highly altered in nature, provide habitat for many species of amphibian. However, the persistence and health of amphibian populations are likely to be compromised by the escalating use of pesticides and other agricultural chemicals. This review examines some of the issues relating to exposure of amphibian populations to these chemicals and places emphasis on mechanisms of toxicity. Several mechanisms are highlighted, including those that may disrupt thyroid activity, retinoid pathways, and sexual differentiation. Special emphasis is also placed on the various interactions that may occur between different agro-chemicals and between chemicals and other environmental factors. We also examine the indirect effects on amphibian populations that occur when their surrounding pond communities are altered by chemicals.
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Affiliation(s)
- Reinier M Mann
- Centre for Ecotoxicology, Department of Environmental Sciences, University of Technology - Sydney, NSW, Australia.
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Olmstead AW, Kosian PA, Korte JJ, Holcombe GW, Woodis KK, Degitz SJ. Sex reversal of the amphibian, Xenopus tropicalis, following larval exposure to an aromatase inhibitor. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2009; 91:143-150. [PMID: 18804292 DOI: 10.1016/j.aquatox.2008.07.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 07/29/2008] [Accepted: 07/31/2008] [Indexed: 05/26/2023]
Abstract
Aromatase is a steroidogenic enzyme that catalyzes the conversion of androgens to estrogens in vertebrates. Modulation of this enzyme's activity by xenobiotic exposure has been shown to adversely affect gonad differentiation in a number of diverse species. We hypothesized that exposure to the aromatase inhibitor, fadrozole, during the larval development of the tropical clawed frog, Xenopus tropicalis, would result in masculinization of the developing female gonad. Tadpoles were exposed to fadrozole at nominal concentrations from 1 to 64 microg/L in a flow-through system from < 24 h post-fertilization (Nieuwkoop Faber (NF) stage 15-20) to metamorphosis (NF stage 66). At metamorphosis, morphologically examined gonads indicated complete masculinization of all tadpoles at concentrations of 16 microg/L and above and a significant bias in sex ratio towards males at concentrations of 1 microg/L and above. No effects on time to metamorphosis, body mass, or body length were observed. A random subsample of frogs was raised to reproductive maturity (39 weeks post-fertilization) in control water. All frogs exposed as tadpoles to 16 microg/L fadrozole or greater possessed testes at sexual maturity. Intersexed gonads characterized by the presence of both testicular and ovarian tissue were observed in 12% of frogs in the 4 microg/L treatment. No differences in estradiol, testosterone, or vitellogenin plasma concentrations were observed in exposed males or females compared to controls. Females in the 4 microg/L treatment possessed a significantly greater percentage of pre-vitellogenic oocytes than controls and were significantly smaller in body mass. No differences in sperm counts were observed in exposed males compared to controls. Results from this study demonstrate that larval exposure to an aromatase inhibitor can result in the complete masculinization of female gonads. These masculinized females are phenotypically indistinguishable from normal males at adulthood. Lower levels of aromatase inhibition resulted in intersexed gonads and possible female reproductive impairment at adulthood. These results indicate that exposure of amphibians to xenobiotics capable of inhibiting aromatase would result in adverse reproductive consequences.
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Affiliation(s)
- Allen W Olmstead
- U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, 6201 Congdon Boulevard, Duluth, MN, USA
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Solomon KR, Carr JA, Du Preez LH, Giesy JP, Kendall RJ, Smith EE, Van Der Kraak GJ. Effects of Atrazine on Fish, Amphibians, and Aquatic Reptiles: A Critical Review. Crit Rev Toxicol 2008; 38:721-72. [DOI: 10.1080/10408440802116496] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Effects of prochloraz and ethinylestradiol on sexual development inRana temporaria. ACTA ACUST UNITED AC 2008; 309:389-98. [DOI: 10.1002/jez.462] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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McDaniel TV, Martin PA, Struger J, Sherry J, Marvin CH, McMaster ME, Clarence S, Tetreault G. Potential endocrine disruption of sexual development in free ranging male northern leopard frogs (Rana pipiens) and green frogs (Rana clamitans) from areas of intensive row crop agriculture. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2008; 88:230-242. [PMID: 18582957 DOI: 10.1016/j.aquatox.2008.05.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Revised: 04/29/2008] [Accepted: 05/02/2008] [Indexed: 05/26/2023]
Abstract
Intensive row crop agriculture (IRCA) for corn and soybean production is predominant in eastern and central North America. IRCA relies heavily on pesticide and nutrient inputs to maximize production under conventional systems. In 2003-2005, we assessed the occurrence of a suite of potential endocrine effects in amphibians inhabiting farm ponds and agricultural drains in IRCA areas of southwestern Ontario. Effects were compared to amphibians from two agricultural reference sites as well as four non-agricultural reference sites. Pesticide and nutrient concentrations were also determined in water samples from those sites. Atrazine and metolachlor were detected in most samples, exceeding 1 microg L(-1) at some sites. Blood samples were taken from northern leopard frogs (Rana pipiens) and green frogs (Rana clamitans) for analysis of circulating sex steroids and vitellogenin-like protein (Vtg-lp), a biomarker of exposure to environmental estrogens. Gonads were histologically examined for evidence of abnormalities. Some evidence of exposure to endocrine disrupting compounds was apparent from the data. The occurrence of testicular ovarian follicles (TOFS) in male R. pipiens was significantly higher (42%; p<0.05) at agricultural sites, particularly those in Chatham county compared to frogs from reference sites (7%). There was no difference in circulating sex steroid levels between frogs from agricultural and reference sites and sex steroid levels did not correlate with pesticide concentrations in the environment. No differences were detected in the gonadosomatic indices or stage of spermatogenesis between frogs from agricultural and non-agricultural regions (p>0.05). Plasma Vtg-lp was detected in only one male R. pipiens from an agricultural site. Neither gonad size, gonad maturity nor sex steroid levels differed between normal males and those with testicular oocytes. Although the proportion of testicular oocytes did not correlate directly with atrazine concentrations, it did correlate with a mixture of pesticides and nutrients, particularly atrazine and nitrate, while the number of pesticides detected at each site was also important.
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Affiliation(s)
- Tana V McDaniel
- Environment Canada, Canada Centre for Inland Waters, Burlington, ON, Canada
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Hertz-Picciotto I, Jusko TA, Willman EJ, Baker RJ, Keller JA, Teplin SW, Charles MJ. A cohort study of in utero polychlorinated biphenyl (PCB) exposures in relation to secondary sex ratio. Environ Health 2008; 7:37. [PMID: 18627595 PMCID: PMC2483969 DOI: 10.1186/1476-069x-7-37] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Accepted: 07/15/2008] [Indexed: 05/02/2023]
Abstract
BACKGROUND Polychlorinated biphenyls (PCBs) are ubiquitous industrial chemicals that persist in the environment and in human fatty tissue. PCBs are related to a class of compounds known as dioxins, specifically 2,3,7,8-TCDD (tetrachloro-dibenzodioxin), which has been implicated as a cause of altered sex ratio, especially in relation to paternal exposures. METHODS In the 1960's, serum specimens were collected from pregnant women participating in the Child Health and Development Study in the San Francisco Bay Area. The women were interviewed and their serum samples stored at -20 degrees C. For this study, samples were thawed and a total of eleven PCBs were determined in 399 specimens. Secondary sex ratio, or sex ratio at birth, was evaluated as a function of maternal serum concentrations using log-binomial and logistic regression, controlling for hormonally active medications taken during pregnancy. RESULTS The relative risk of a male birth decreased by 33% comparing women at the 90th percentile of total PCBs with women at the 10th percentile (RR = 0.67; 95% CI, 0.48-0.94; p = 0.02), or by approximately 7% for each 1 mug/L increase in total PCB concentration. Although some congener-specific associations with sex ratio were only marginally statistically significant, all nine PCB congeners with < 30% of samples below the LOQ showed the same direction of association, an improbable finding under the null hypothesis. CONCLUSION Maternal exposure to PCBs may be detrimental to the success of male sperm or to the survival of male embryos. Findings could be due to contaminants, metabolites or PCBs themselves.
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Affiliation(s)
- Irva Hertz-Picciotto
- Department of Public Health Sciences, School of Medicine, TB #168, University of California-Davis, Davis, CA, 95616, USA
| | - Todd A Jusko
- Department of Epidemiology, School of Public Health and Community Medicine, University of Washington, Box 357236, Seattle, WA, 98195, USA
| | - Eric J Willman
- Department of Environmental Toxicology, University of California-Davis, Davis, CA, 95616, USA
- Ecolab, Eagen, MN, 55121, USA
| | - Rebecca J Baker
- Department of Epidemiology, School of Public Health, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Jean A Keller
- Department of Epidemiology, School of Public Health, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA
- Quintiles, Inc, 5927 South Miami Blvd, Morrisville, NC, 27560, USA
| | - Stuart W Teplin
- Center for the Study of Development and Learning, Department of Pediatrics, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC, 27599, USA
| | - M Judith Charles
- Department of Environmental Toxicology, University of California-Davis, Davis, CA, 95616, USA
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Quantification of atrazine and its metabolites in urine by on-line solid-phase extraction–high-performance liquid chromatography–tandem mass spectrometry. Anal Bioanal Chem 2008; 391:1931-9. [DOI: 10.1007/s00216-008-2102-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 03/20/2008] [Accepted: 03/25/2008] [Indexed: 11/26/2022]
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Cevasco A, Urbatzka R, Bottero S, Massari A, Pedemonte F, Kloas W, Mandich A. Endocrine disrupting chemicals (EDC) with (anti)estrogenic and (anti)androgenic modes of action affecting reproductive biology of Xenopus laevis: II. Effects on gonad histomorphology. Comp Biochem Physiol C Toxicol Pharmacol 2008; 147:241-51. [PMID: 18032117 DOI: 10.1016/j.cbpc.2007.10.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 10/12/2007] [Accepted: 10/15/2007] [Indexed: 11/22/2022]
Abstract
A number of man-made chemicals has been shown to mimic endogenous hormones and to induce alterations of reproductive physiology in wild populations. Of particular importance are compounds that mimic estrogens and androgens (and their antagonists), because of their central role in reproductive function. In this study, male and female adult South African clawed toads (Xenopus laevis) were exposed to ethinylestradiol (EE2), tamoxifen (TAM), methyldihydrotestosterone (MDHT) and flutamide (FLU) as (anti)estrogenic and (anti)androgenic model compounds, respectively, at a concentration of 10(-8) M, and to water from the river Lambro (LAM), a contaminated watercourse from Northern Italy. Potential disrupting effects on reproduction were studied by histological analyses of gonads. The strongest adverse effects were observed in EE2 and LAM exposed males, e.g. tubule mean diameter reduction, spermatogenic nest breakdown and interlobular wall thickening. In both groups, the occurrence of small oocytes within the seminiferous tubules was observed. In TAM and MDHT exposed females slight oocyte atresia and occurrence of spermatogenic nests were observed. In contrast to previous studies addressing the alteration of molecular biomarkers in the same experimental setup, histological analyses of gonads were very sensitive and indicated an adverse effect of water from Lambro River on reproductive physiology of X. laevis.
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Steinberg RM, Walker DM, Juenger TE, Woller MJ, Gore AC. Effects of perinatal polychlorinated biphenyls on adult female rat reproduction: development, reproductive physiology, and second generational effects. Biol Reprod 2008; 78:1091-101. [PMID: 18305224 DOI: 10.1095/biolreprod.107.067249] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Perinatal exposures to endocrine-disrupting chemicals, such as polychlorinated biphenyls (PCBs), can cause latent effects on reproductive function. Here, we tested whether PCBs administered during late pregnancy would compromise reproductive physiology in both the fetally exposed female offspring (F1 generation), as well as in their female offspring (F2 generation). Pregnant Sprague-Dawley rats were treated with the PCB mixture, Aroclor 1221 (A1221; 0, 0.1, 1, or 10 mg/kg), on Embryonic Days 16 and 18. Somatic and reproductive development of F1 and their F2 female offspring were monitored, including ages of eye opening, pubertal landmarks, and serum reproductive hormones. The results showed that low doses of A1221 given during this critical period of neuroendocrine development caused differential effects of A1221 on F1 and F2 female rats. In both generations, litter sex ratio was skewed toward females. In the F1 generation, additional effects were found, including a significant alteration of serum LH in the 1 mg/kg A1221 group. The F2 generation showed more profound alterations, particularly with respect to fluctuations in hormones and reproductive tract tissues across the estrous cycle. On proestrus, the day of the preovulatory GnRH/gonadotropin surge, F2 females whose mothers had been exposed perinatally to A1221 exhibited substantially suppressed LH and progesterone concentrations, and correspondingly smaller uterine and ovarian weights on estrus, compared with F2 descendants of control rats. These latter changes suggest a dysregulation of reproductive physiology. Thus, low levels of exposure to PCBs during late fetal development cause significant effects on the maturation and physiology of two generations of female offspring. These findings have implications for reproductive health and fertility of wildlife and humans.
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Affiliation(s)
- Rebecca M Steinberg
- The Institute for Neuroscience, The University of Texas at Austin, Austin, Texas 78712, USA
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Jofré MB, Karasov WH. Effect of mono-ortho and di-ortho substituted polychlorinated biphenyl (PCB) congeners on leopard frog survival and sexual development. CHEMOSPHERE 2008; 70:1609-19. [PMID: 17870144 DOI: 10.1016/j.chemosphere.2007.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Revised: 07/27/2007] [Accepted: 08/01/2007] [Indexed: 05/17/2023]
Abstract
We tested the effect of mono-ortho and di-ortho PCB congeners on northern leopard frog (Rana pipiens) hatching success, survival and sexual development. Embryos and tadpoles were exposed to two levels (0.5 and 50 microg/l) of two PCBs. PCBs 101 and 70 were selected because they were present in amphibians collected in the Fox River-Green Bay ecosystem and they have the theoretical structural requirements to be able to bind to the estrogen receptor and mediate estrogenic responses. The exposure of leopard frog embryos and tadpoles to PCB 70 and 101 did not significantly affect hatchability, survival, deformities or growth. There were significant departures from the expected 50:50 sex ratio in tadpoles/froglets exposed to PCB 101 and PCB 70. In all the cases of significant departure, the bias was towards higher number of females. Decrease in the proportion of male gonads and increase in the proportion of intersex gonads were observed with increasing PCB tissue concentrations. The effects of PCB congeners on sexual differentiation occur at concentrations higher than observed in frogs in the Fox River/Green Bay ecosystem.
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Affiliation(s)
- Mariana Beatriz Jofré
- Area de Biología, Departamento de Bioquímica y Ciencias Biológicas, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis, Argentina.
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LaFiandra EM, Babbitt KJ, Sower SA. Effects of atrazine on anuran development are altered by the presence of a nonlethal predator. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2008; 71:505-511. [PMID: 18338285 DOI: 10.1080/15287390801907442] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Although predator-induced stress is a common biotic factor in aquatic communities that can strongly influence anuran development, there have been no studies to date that examined the interaction between this factor and atrazine, the most widely used pesticide in the United States. The potential synergistic effects of atrazine (0, 20, or 200 microg/L) and predatory stress on the survival, growth, development, and reproductive development of Hyla versicolor (gray treefrog) tadpoles were investigated. Atrazine reduced the proportion of tadpoles reaching metamorphosis; however, this effect was modified by the presence of a nonlethal predator. The combined effects of predatory stress and exposure to 200 microg/L atrazine resulted in the lowest proportion of tadpoles reaching metamorphosis. No treatment effects were observed for mass, snout-urostyle length, or the proportion of metamorphs that were male or female. No macroscopic gonadal anomalies were observed. Many gonads were underdeveloped; however, gonadal development was more advanced in metamorphs exposed to 200 microg/L atrazine. This effect was modified by the presence of a nonlethal predator such that female gonadal development was further accelerated and male gonadal development was retarded by predatory stress. These results indicate that simplified laboratory studies may not accurately reflect the effects of atrazine on anuran development in natural communities.
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Orlando EF, Guillette LJ. Sexual dimorphic responses in wildlife exposed to endocrine disrupting chemicals. ENVIRONMENTAL RESEARCH 2007; 104:163-73. [PMID: 16890221 DOI: 10.1016/j.envres.2006.06.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Revised: 06/09/2006] [Accepted: 06/10/2006] [Indexed: 05/11/2023]
Abstract
Understanding the gender similarities and differences in how organisms respond following exposure to environmental chemicals is important if we are to determine the relative risk of these agents to wildlife and human populations. In this paper, we have chosen to focus on the sex determination and differentiation of fishes, amphibians, and reptiles, because of their close association with the environment and the number of environmental factors (e.g., temperature and endocrine disrupting chemicals) that are known to affect these phenomena in these taxa. We have discussed examples of gender differences in response to exposure to endocrine disrupting chemicals and found gender similarities about as often as we found differences. We found that most studies examined either one sex exclusively, or the experimental design did not include examining the effect of sex as a variable. Given the central role of sex steroid hormones in the sex determination and sexual differentiation of fishes, amphibians, and reptiles, we recommend that future research purposefully include sex as a factor, so that risk assessment by government agencies can address the probable gender differences in effects from exposure to chemicals in the environment.
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Affiliation(s)
- Edward F Orlando
- Harbor Branch Oceanographic Institution Campus, Florida Atlantic University, 5600 US 1, North, Ft. Pierce, FL 34946, USA.
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Fan W, Yanase T, Morinaga H, Gondo S, Okabe T, Nomura M, Komatsu T, Morohashi KI, Hayes TB, Takayanagi R, Nawata H. Atrazine-induced aromatase expression is SF-1 dependent: implications for endocrine disruption in wildlife and reproductive cancers in humans. ENVIRONMENTAL HEALTH PERSPECTIVES 2007; 115:720-7. [PMID: 17520059 PMCID: PMC1867956 DOI: 10.1289/ehp.9758] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Accepted: 02/05/2007] [Indexed: 05/15/2023]
Abstract
BACKGROUND Atrazine is a potent endocrine disruptor that increases aromatase expression in some human cancer cell lines. The mechanism involves the inhibition of phosphodiesterase and subsequent elevation of cAMP. METHODS We compared steroidogenic factor 1 (SF-1) expression in atrazine responsive and non-responsive cell lines and transfected SF-1 into nonresponsive cell lines to assess SF-1's role in atrazine-induced aromatase. We used a luciferase reporter driven by the SF-1-dependent aromatase promoter (ArPII) to examine activation of this promoter by atrazine and the related simazine. We mutated the SF-1 binding site to confirm the role of SF-1. We also examined effects of 55 other chemicals. Finally, we examined the ability of atrazine and simazine to bind to SF-1 and enhance SF-1 binding to ArPII. RESULTS Atrazine-responsive adrenal carcinoma cells (H295R) expressed 54 times more SF-1 than nonresponsive ovarian granulosa KGN cells. Exogenous SF-1 conveyed atrazine-responsiveness to otherwise nonresponsive KGN and NIH/3T3 cells. Atrazine induced binding of SF-1 to chromatin and mutation of the SF-1 binding site in ArPII eliminated SF-1 binding and atrazine-responsiveness in H295R cells. Out of 55 chemicals examined, only atrazine, simazine, and benzopyrene induced luciferase via ArPII. Atrazine bound directly to SF-1, showing that atrazine is a ligand for this "orphan" receptor. CONCLUSION The current findings are consistent with atrazine's endocrine-disrupting effects in fish, amphibians, and reptiles; the induction of mammary and prostate cancer in laboratory rodents; and correlations between atrazine and similar reproductive cancers in humans. This study highlights the importance of atrazine as a risk factor in endocrine disruption in wildlife and reproductive cancers in laboratory rodents and humans.
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Affiliation(s)
- WuQiang Fan
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan
| | - Toshihiko Yanase
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan
| | - Hidetaka Morinaga
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan
| | - Shigeki Gondo
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan
| | - Taijiro Okabe
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan
| | - Masatoshi Nomura
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan
| | - Tomoko Komatsu
- Department of Developmental Biology, National Institute for Basic Biology, Okazaki, Japan
| | - Ken-Ichirou Morohashi
- Department of Developmental Biology, National Institute for Basic Biology, Okazaki, Japan
| | - Tyrone B. Hayes
- Laboratory for Integrative Studies in Amphibian Biology, Group in Endocrinology, Museum of Vertebrate Zoology, Energy and Resources Group, and Department of Integrative Biology, University of California, Berkeley, California, USA
| | - Ryoichi Takayanagi
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan
| | - Hajime Nawata
- Graduate School of Medical Science, Kyushu University, Fukuoka, Japan
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48
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Maglia AM, Pugener LA, Mueller JM. Skeletal morphology and postmetamorphic ontogeny ofAcris crepitans (Anura: Hylidae): A case of miniaturization in frogs. J Morphol 2007; 268:194-223. [PMID: 17278133 DOI: 10.1002/jmor.10508] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Acris crepitans is a small, semiaquatic member of the treefrog family Hylidae. Much recent attention has been paid to this species because of reports of population declines and malformations, yet few works have considered the skeletal anatomy of this common North American frog. Herein, we provide a detailed description of the morphology and adult ontogeny of the skeleton of A. crepitans, and discuss novel morphologies, interesting postmetamorphic developmental patterns, and intraspecific skeletal variation. The reduced amount of adult ossification, as well as several novel morphologies present in this species, are consistent with patterns of miniaturization seen in other anurans. For example, the skull is poorly ossified, but most of the cranial cartilages are heavily mineralized, the nasal bones are fused to endochondral ossification of the tectum nasi, the palatines are reduced, and the prootics and exoccipitals are not fused to one another (although the prootics are well-developed and ornamented). In addition, several specimens exhibit abnormalities, which might indicate that: (1) the population was under an acute malformation outbreak, (2) a high incidence of small skeletal malformations is normal in this species, (3) the population is under stress because of habitat fragmentation, (4) there is environmental deterioration in the region where the specimens were collected, and/or (5) the species is now showing signs of decline in southern Missouri. Regardless of the cause, it is clear that further examination of skeletal variability in A. crepitans, including ossification patterns and the frequency of abnormalities, is warranted.
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Affiliation(s)
- Anne M Maglia
- Department of Biological Sciences, University of Missouri-Rolla, Rolla, Missouri 65409, USA.
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49
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Olmstead AW, LeBlanc GA. The environmental-endocrine basis of gynandromorphism (intersex) in a crustacean. Int J Biol Sci 2006; 3:77-84. [PMID: 17205107 PMCID: PMC1752225 DOI: 10.7150/ijbs.3.77] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Accepted: 11/30/2006] [Indexed: 11/22/2022] Open
Abstract
Commensurate with the decline in many crustacean populations has been an accumulation in reports of sexually ambiguous individuals within these populations. The cause of gynandromorphism or intersex among crustaceans is unknown. We show that gynandromorphism in the branchiopod crustacean Daphnia magna is initiated by the sex-determining hormone methyl farnesoate when levels of the hormone are intermediate between low levels that stimulate the production of broods containing all female offspring and high levels that stimulate the production of broods of all male offspring. The incidence of hormonally-induced gynandromorphism was low (0.14% at the maximum stimulatory hormone concentrations) but was significantly increased (46-fold) when the animals were hormone-treated at 30oC. Some environmental chemicals also can stimulate the gynandromorphic phenotype as we demonstrated with the insecticide pyriproxyfen. Gynandromorphism occurs due to inadequate signaling of male-sex determination since: a) gynandromorphs did not occur in a population that was producing only female offspring; and, b) conditions that stimulated gynandromorphism also reduced the incidence of male offspring. We suggest that male sex determination normally occurs prior to the first embryonic cleavage. Elevated temperature may alter the timing of sex determination such that methyl farnesoate signaling occurs after the first embryonic cleavage and bilateral gynandromorphism occurs as a consequence of signaling to only one of the daughter cells. These results demonstrate that environmental factors can cause aberrant sex determination via perturbations in methyl farnesoate signaling.
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Affiliation(s)
- Allen W Olmstead
- Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695-7633, USA
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50
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Matsushita S, Yamashita J, Iwasawa T, Tomita T, Ikeda M. Effects of in ovo exposure to imazalil and atrazine on sexual differentiation in chick gonads. Poult Sci 2006; 85:1641-7. [PMID: 16977851 DOI: 10.1093/ps/85.9.1641] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We examined the effects of atrazine and imazalil, 2 commonly used pesticides, on sexual differentiation in chickens. Atrazine and imazalil were injected into fertile eggs on d 0. At hatching, sex genotype and phenotype were determined. Gonads were stereomicroscopically and histologically observed. In ovo exposure of atrazine (0.01 to 3 mg/egg) did not influence hatchability, whereas imazalil exposure (2 mg/egg) inhibited hatchability. The sex genotype matched the sex phenotype in controls, atrazine, and imazalil-exposed groups. In control females, the right gonad was regressed at hatching. Regression of the right gonad, however, was inhibited following atrazine and imazalil exposure. In atrazine-exposed female chicks, the left gonads had normal ovary structures, and the remaining right gonads had ovary medulla-like structures. In imazalil-exposed females, some left gonads had an ovary medulla-like structure without the cortex as well as tubules, and the right gonad had testis-like structures. There was no change in male gonads at hatching following atrazine and imazalil exposure. Aromatase activity of the left gonad from female chicks was not changed by any concentration of atrazine exposure. These results suggest that atrazine and imazalil inhibit regression of the right gonad in female chicks, although it is not clear whether the remaining right gonad has aromatase activity. In ovo exposure to atrazine influences sexual differentiation of the ovary by different mechanisms from imazalil, possibly by the induction of aromatase in the right gonad, whereas it is confirmed that imazalil inhibits in vitro aromatase activity in the chick ovary. The results indicated that in ovo exposure to imazalil inhibits sexual differentiation of the ovary by inhibiting aromatase activity.
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Affiliation(s)
- S Matsushita
- Shizuoka Swine and Poultry Experiment Station, Kikugawa, Shizuoka, 439-0037, Japan
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