1
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Esmaeilbeigi M, P Duncan R, J Kefford B, Ezaz T, Clulow S. Evidence for a metal disease refuge: The amphibian-killing fungus (Batrachochytrium dendrobatidis) is inhibited by environmentally-relevant concentrations of metals tolerated by amphibians. ENVIRONMENTAL RESEARCH 2024:119752. [PMID: 39117053 DOI: 10.1016/j.envres.2024.119752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Revised: 07/27/2024] [Accepted: 08/05/2024] [Indexed: 08/10/2024]
Abstract
The amphibian-killing fungus Batrachochytrium dendrobatidis (Bd) has caused substantial declines in Bd-susceptible amphibian species worldwide. However, some populations of Bd-susceptible frogs have managed to survive at existing metal-polluted sites, giving rise to the hypothesis that frogs might persist in the presence of Bd if Bd is inhibited by metals at concentrations that frogs can tolerate. We tested this hypothesis by measuring the survival of Bd zoospores, the life stage that infects amphibians, and calculated the LC50 after exposure to environmentally-relevant elevated concentrations of copper (Cu), zinc (Zn), and their combination (Cu+Zn) in two repeated 4-day acute exposure runs. We also measured the chronic sensitivity of Bd to these metals over three generations by measuring the number of colonies and live zoospores and calculating EC50 concentrations after 42 days of exposure. We then compared acute and chronic sensitivity of Bd with amphibian sensitivities by constructing species sensitivity distributions (SSDs) using LC50 and EC50 data obtained from the literature. Acute sensitivity data showed that Bd zoospore survival decreased with increasing metal concentrations and exposure durations relative to the control, with the highest LC50 values for Cu and Zn being 2.5 μg/L and 250 μg/L, respectively. Chronic exposures to metals resulted in decreased numbers of Bd colonies and live zoospores after 42 days, with EC50 values of 0.75 μg/L and 1.19 μg/L for Cu and Zn, respectively. Bd zoospore survival was 10 and 8 times more sensitive to Cu and Zn, respectively in acute, and 2 and 5 times more sensitive to Cu and Zn in chronic exposure experiments than the most sensitive amphibian species recorded. Our findings are consistent with the hypothesis that metals in existing metal-polluted sites may have a greater impact on Bd relative to amphibians' performance, potentially enabling Bd-susceptible amphibians to persist with Bd at these sites.
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Affiliation(s)
- Milad Esmaeilbeigi
- Centre for Applied Water Science, Institute for Applied Ecology, Faculty of Science and Technology, University of Canberra, Canberra, Bruce ACT 2617, Australia.
| | - Richard P Duncan
- Center for Conservation Ecology and Genomics, Institute for Applied Ecology, Faculty of Science and Technology, University of Canberra, Canberra, Bruce ACT 2617, Australia.
| | - Ben J Kefford
- Centre for Applied Water Science, Institute for Applied Ecology, Faculty of Science and Technology, University of Canberra, Canberra, Bruce ACT 2617, Australia.
| | - Tariq Ezaz
- Center for Conservation Ecology and Genomics, Institute for Applied Ecology, Faculty of Science and Technology, University of Canberra, Canberra, Bruce ACT 2617, Australia.
| | - Simon Clulow
- Center for Conservation Ecology and Genomics, Institute for Applied Ecology, Faculty of Science and Technology, University of Canberra, Canberra, Bruce ACT 2617, Australia.
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2
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Chew A, West M, Berger L, Brannelly LA. The impacts of water quality on the amphibian chytrid fungal pathogen: A systematic review. ENVIRONMENTAL MICROBIOLOGY REPORTS 2024; 16:e13274. [PMID: 38775382 PMCID: PMC11110485 DOI: 10.1111/1758-2229.13274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 04/06/2024] [Indexed: 05/25/2024]
Abstract
The pathogenic fungus Batrachochytrium dendrobatidis has caused declines of amphibians worldwide. Yet our understanding of how water quality influences fungal pathogenicity is limited. Here, we reviewed experimental studies on the effect of water quality on this pathogen to determine which parameters impacted disease dynamics consistently. The strongest evidence for protective effects is salinity which shows strong antifungal properties in hosts at natural levels. Although many fungicides had detrimental effects on the fungal pathogen in vitro, their impact on the host is variable and they can worsen infection outcomes. However, one fungicide, epoxiconazole, reduced disease effects experimentally and likely in the field. While heavy metals are frequently studied, there is weak evidence that they influence infection outcomes. Nitrogen and phosphorous do not appear to impact pathogen growth or infection in the amphibian host. The effects of other chemicals, like pesticides and disinfectants on infection were mostly unclear with mixed results or lacking an in vivo component. Our study shows that water chemistry does impact disease dynamics, but the effects of specific parameters require more investigation. Improving our understanding of how water chemistry influences disease dynamics will help predict the impact of chytridiomycosis, especially in amphibian populations affected by land use changes.
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Affiliation(s)
- Adeline Chew
- School of BiosciencesThe University of MelbourneParkvilleVictoriaAustralia
| | - Matt West
- School of BiosciencesThe University of MelbourneParkvilleVictoriaAustralia
| | - Lee Berger
- Melbourne Veterinary SchoolThe University of MelbourneWerribeeVictoriaAustralia
| | - Laura A. Brannelly
- Melbourne Veterinary SchoolThe University of MelbourneWerribeeVictoriaAustralia
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3
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Salla RF, Costa MJ, Abdalla FC, Oliveira CR, Tsukada E, Boeing GANS, Prado J, Carvalho T, Ribeiro LP, Rebouças R, Toledo LF. Estrogen contamination increases vulnerability of amphibians to the deadly chytrid fungus. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 917:170337. [PMID: 38301782 DOI: 10.1016/j.scitotenv.2024.170337] [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: 10/16/2023] [Revised: 12/31/2023] [Accepted: 01/19/2024] [Indexed: 02/03/2024]
Abstract
Aquatic contaminants and infectious diseases are among the major drivers of global amphibian declines. However, the interaction of these factors is poorly explored and could better explain the amphibian crisis. We exposed males and females of the Brazilian Cururu Toad, Rhinella icterica, to an environmentally relevant concentration of the estrogen 17-alpha-ethinylestradiol (an emerging contaminant) and to the chytrid infection (Batrachochytrium dendrobatidis), in their combined and isolated forms, and the ecotoxicity was determined by multiple biomarkers: cutaneous, hematological, cardiac, hepatic, and gonadal analysis. Our results showed that Cururu toads had many physiological alterations in response to the chytrid infection, including the appearance of cutaneous Langerhans's cells, increased blood leukocytes, increased heart contraction force and tachycardia, increased hepatic melanomacrophage cells, which in turn led to gonadal atrophy. The estrogen, in turn, increased the susceptibility of the toads to the chytrid infection (higher Bd loads) and maximized the deleterious effects of the pathogen: reducing leukocytes, decreasing the contraction force, and causing greater tachycardia, increasing hepatic melanomacrophage cells, and leading to greater gonadal atrophy, which were more extreme in females. The exposure to estrogen also revealed important toxicodynamic pathways of this toxicant, as shown by the immunosuppression of exposed animals, and the induction of the first stages of feminization in males, which corroborates that the synthetic estrogen acts as an endocrine disruptor. Such an intricate relationship is unprecedented and reinforces the importance of studying the serious consequences that multiple environmental stressors can cause to aquatic populations.
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Affiliation(s)
- Raquel F Salla
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Campinas, São Paulo, Brazil; Programa de Pós-graduação em Biotecnologia e Monitoramento Ambiental (PPGBMA), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil.
| | - Monica Jones Costa
- Programa de Pós-graduação em Biotecnologia e Monitoramento Ambiental (PPGBMA), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil; Laboratório de Fisiologia da Conservação (LaFisC), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil
| | - Fabio Camargo Abdalla
- Programa de Pós-graduação em Biotecnologia e Monitoramento Ambiental (PPGBMA), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil; Laboratório de Biologia Estrutural e Funcional (LaBEF), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil
| | - Cristiane R Oliveira
- Programa de Pós-graduação em Biotecnologia e Monitoramento Ambiental (PPGBMA), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil
| | - Elisabete Tsukada
- Programa de Pós-graduação em Biotecnologia e Monitoramento Ambiental (PPGBMA), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil
| | - Guilherme Andrade Neto Schmitz Boeing
- Programa de Pós-graduação em Biotecnologia e Monitoramento Ambiental (PPGBMA), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil; Laboratório de Biologia Estrutural e Funcional (LaBEF), Universidade Federal de São Carlos, Sorocaba, São Paulo, Brazil
| | - Joelma Prado
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Campinas, São Paulo, Brazil
| | - Tamilie Carvalho
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Campinas, São Paulo, Brazil; Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Luisa P Ribeiro
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Campinas, São Paulo, Brazil
| | - Raoni Rebouças
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Campinas, São Paulo, Brazil
| | - Luís Felipe Toledo
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas (Unicamp), Campinas, São Paulo, Brazil
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4
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Martínez-Ruiz EB, Agha R, Spahr S, Wolinska J. Widely used herbicide metolachlor can promote harmful bloom formation by stimulating cyanobacterial growth and driving detrimental effects on their chytrid parasites. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 344:123437. [PMID: 38272168 DOI: 10.1016/j.envpol.2024.123437] [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: 08/29/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 01/27/2024]
Abstract
Metolachlor (MET) is a widely used herbicide that can adversely affect phytoplanktonic non-target organisms, such as cyanobacteria. Chytrids are zoosporic fungi ubiquitous in aquatic environments that parasitize cyanobacteria and can keep their proliferation in check. However, the influence of organic pollutants on the interaction between species, including parasitism, and the associated ecological processes remain poorly understood. Using the host-parasite system consisting of the toxigenic cyanobacterium Planktothrix agardhii and its chytrid parasite Rhizophydium megarrhizum, we investigated the effects of environmentally relevant concentrations of MET on host-parasite interactions under i) continuous exposure of chytrids and cyanobacteria, and ii) pre-exposure of chytrids. During a continuous exposure, the infection prevalence and intensity were not affected, but chytrid reproductive structures were smaller at the highest tested MET concentration. In the parasite's absence, MET promoted cyanobacteria growth possibly due to a hormesis effect. In the pre-exposure assay, MET caused multi- and transgenerational detrimental effects on parasite fitness. Chytrids pre-exposed to MET showed reduced infectivity, intensity, and prevalence of the infection, and their sporangia size was reduced. Thus, pre-exposure of the parasite to MET resulted in a delayed decline of the cyanobacterial cultures upon infection. After several parasite generations without MET exposure, the parasite recovered its initial fitness, indicating that detrimental effects are transient. This study demonstrates that widely used herbicides, such as MET, could favor cyanobacterial bloom formation both directly, by promoting cyanobacteria growth, and indirectly, by inhibiting their chytrid parasites, which are known to play a key role as top-down regulators of cyanobacteria. In addition, we evidence the relevance of addressing multi-organism systems, such as host-parasite interactions, in toxicity assays. This approach offers a more comprehensive understanding of the effects of pollutants on aquatic ecosystems.
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Affiliation(s)
- Erika Berenice Martínez-Ruiz
- Department of Evolutionary and Integrative Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany.
| | - Ramsy Agha
- Department of Evolutionary and Integrative Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
| | - Stephanie Spahr
- Department of Ecohydrology and Biogeochemistry, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
| | - Justyna Wolinska
- Department of Evolutionary and Integrative Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany; Department of Biology, Chemistry, Pharmacy, Institute of Biology, Freie Universität Berlin, Germany
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5
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Blewett TA, Ackerly KL, Schlenker LS, Martin S, Nielsen KM. Implications of biotic factors for toxicity testing in laboratory studies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 908:168220. [PMID: 37924878 DOI: 10.1016/j.scitotenv.2023.168220] [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: 07/11/2023] [Revised: 10/25/2023] [Accepted: 10/28/2023] [Indexed: 11/06/2023]
Abstract
There is an emerging call from scientists globally to advance the environmental relevance of laboratory studies, particularly within the field of ecotoxicology. To answer this call, we must carefully examine and elucidate the shortcomings of standardized toxicity testing methods that are used in the derivation of toxicity values and regulatory criteria. As a consequence of rapidly accelerating climate change, the inclusion of abiotic co-stressors are increasingly being incorporated into toxicity studies, with the goal of improving the representativeness of laboratory-derived toxicity values used in ecological risk assessments. However, much less attention has been paid to the influence of biotic factors that may just as meaningfully impact our capacity to evaluate and predict risks within impacted ecosystems. Therefore, the overarching goal is to highlight key biotic factors that should be taken into consideration during the experimental design and model selection phase. SYNOPSIS: Scientists are increasingly finding that lab reared results in toxicology might not be reflective of the external wild environment, we highlight in this review some key considerations when working between the lab and field.
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Affiliation(s)
- Tamzin A Blewett
- University of Alberta, Department of Biological Sciences, Canada.
| | - Kerri Lynn Ackerly
- The University of Texas at Austin, Marine Science Institute, United States of America
| | - Lela S Schlenker
- East Carolina University, Department of Biology, United States of America
| | - Sidney Martin
- University of Alberta, Department of Biological Sciences, Canada
| | - Kristin M Nielsen
- The University of Texas at Austin, Marine Science Institute, United States of America
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6
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Barragan EM, Hoskins TD, Allmon EB, McQuigg JL, Hamilton MT, Christian EN, Coogan GSM, Searle CL, Choi YJ, Lee LS, Hoverman JT, Sepúlveda MS. Toxicities of Legacy and Current-Use PFAS in an Anuran: Do Larval Exposures Influence Responses to a Terrestrial Pathogen Challenge? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:19180-19189. [PMID: 37962853 DOI: 10.1021/acs.est.3c03191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Legacy polyfluoroalkyl substances (PFAS) [perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA)] are being replaced by various other fluorinated compounds, such as hexafluoropropylene oxide dimer acid (GenX). These alternatives are thought to be less bioaccumulative and, therefore, less toxic than legacy PFAS. Contaminant exposures occur concurrently with exposure to natural stressors, including the fungal pathogen Batrachocytrium dendrobatidis (Bd). Despite evidence that other pollutants can increase the adverse effects of Bd on anurans, no studies have examined the interactive effects of Bd and PFAS. This study tested the growth and developmental effects of PFOS, PFOA, and GenX on gray treefrog (Hyla versicolor) tadpoles, followed by a Bd challenge after metamorphosis. Despite PFAS exposure only occurring during the larval stage, carry-over effects on growth were observed post metamorphosis. Further, PFAS interacted with Bd exposure to influence growth; Bd-exposed animals had significantly shorter SVL [snout-vent length (mm)] with significantly increased body condition, among other time-dependent effects. Our data suggest that larval exposure to PFAS can continue to impact growth in the juvenile stage after exposure has ended. Contrary to predictions, GenX affected terrestrial performance more consistently than its legacy congener, PFOA. Given the role of Bd in amphibian declines, further investigation of interactions of PFAS with Bd and other environmentally relevant pathogens is warranted.
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Affiliation(s)
- Evelyn M Barragan
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana 47907, United States
| | - Tyler D Hoskins
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana 47907, United States
| | - Elizabeth B Allmon
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana 47907, United States
| | - Jessica L McQuigg
- Department of Biology, Drew University, Madison, New Jersey 07940, United States
| | - Matthew T Hamilton
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana 47907, United States
| | - Erin N Christian
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana 47907, United States
| | - Grace S M Coogan
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana 47907, United States
| | - Catherine L Searle
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, United States
| | - Youn Jeong Choi
- Agronomy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Linda S Lee
- Agronomy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Jason T Hoverman
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana 47907, United States
| | - Maria S Sepúlveda
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana 47907, United States
- Sustainability Research Center and PhD in Conservation Medicine, Life Sciences Faculty, Universidad Andres Bello, Santiago 7550196, Chile
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7
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Paetow LJ, Cue RI, Pauli BD, Marcogliese DJ. Effects of Herbicides and the Chytrid Fungus Batrachochytrium dendrobatidis on the growth, development and survival of Larval American Toads (Anaxyrus americanus). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 259:115021. [PMID: 37216860 DOI: 10.1016/j.ecoenv.2023.115021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 05/08/2023] [Accepted: 05/14/2023] [Indexed: 05/24/2023]
Abstract
Pesticides and pathogens adversely affect amphibian health, but their interactive effects are not well known. We assessed independent and combined effects of two agricultural herbicides and the fungal pathogen Batrachochytrium dendrobatidis (Bd) on the growth, development and survival of larval American toads (Anaxyrus americanus). Wild-caught tadpoles were exposed to four concentrations of atrazine (0.18, 1.8, 18.0, 180 μg/L) or glyphosate (7, 70, 700, 7000 µg a.e./L), respectively contained in Aatrex® Liquid 480 (Syngenta) or Vision® Silviculture Herbicide (Monsanto) for 14 days, followed by two doses of Bd. At day 14, atrazine had not affected survival, but it non-monotonically affected growth. Exposure to the highest concentration of glyphosate caused 100% mortality within 4 days, while lower doses had an increasing monotonic effect on growth. At day 65, tadpole survival was unaffected by atrazine and the lower doses of glyphosate. Neither herbicide demonstrated an interaction effect with Bd on survival, but exposure to Bd increased survival among both herbicide-exposed and herbicide-control tadpoles. At day 60, tadpoles exposed to the highest concentration of atrazine remained smaller than controls, indicating longer-term effects of atrazine on growth, but effects of glyphosate on growth disappeared. Growth was unaffected by any herbicide-fungal interaction but was positively affected by exposure to Bd following exposure to atrazine. Atrazine exhibited a slowing and non-monotonic effect on Gosner developmental stage, while exposure to Bd tended to speed up development and act antagonistically toward the observed effect of atrazine. Overall, atrazine, glyphosate and Bd all showed a potential to modulate larval toad growth and development.
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Affiliation(s)
- Linda J Paetow
- Department of Biology, Concordia University, 7141 Sherbrooke St. W, Montreal, Quebec H4B 1R6, Canada.
| | - Roger I Cue
- Department of Animal Science, McGill University, 21111 Lakeshore Rd., Ste. Anne-de-Bellevue, Quebec H9X 3V9, Canada
| | - Bruce D Pauli
- Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1A 0H3, Canada
| | - David J Marcogliese
- Aquatic Contaminants Research Division, Water Science and Technology Directorate, Science and Technology Branch, St. Lawrence Centre, Environment and Climate Change Canada, 105 McGill, 7th Floor, Montreal, Quebec H2Y 2E7, Canada
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8
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Humphries JE, Lanctôt CM, Robert J, McCallum HI, Newell DA, Grogan LF. Do immune system changes at metamorphosis predict vulnerability to chytridiomycosis? An update. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2022; 136:104510. [PMID: 35985564 DOI: 10.1016/j.dci.2022.104510] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 06/20/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
Amphibians are among the vertebrate groups suffering great losses of biodiversity due to a variety of causes including diseases, such as chytridiomycosis (caused by the fungal pathogens Batrachochytrium dendrobatidis and B. salamandrivorans). The amphibian metamorphic period has been identified as being particularly vulnerable to chytridiomycosis, with dramatic physiological and immunological reorganisation likely contributing to this vulnerability. Here, we overview the processes behind these changes at metamorphosis and then perform a systematic literature review to capture the breadth of empirical research performed over the last two decades on the metamorphic immune response. We found that few studies focused specifically on the immune response during the peri-metamorphic stages of amphibian development and fewer still on the implications of their findings with respect to chytridiomycosis. We recommend future studies consider components of the immune system that are currently under-represented in the literature on amphibian metamorphosis, particularly pathogen recognition pathways. Although logistically challenging, we suggest varying the timing of exposure to Bd across metamorphosis to examine the relative importance of pathogen evasion, suppression or dysregulation of the immune system. We also suggest elucidating the underlying mechanisms of the increased susceptibility to chytridiomycosis at metamorphosis and the associated implications for population persistence. For species that overlap a distribution where Bd/Bsal are now endemic, we recommend a greater focus on management strategies that consider the important peri-metamorphic period.
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Affiliation(s)
- Josephine E Humphries
- School of Environment and Science, Griffith University, Southport, Queensland, 4222, Australia; Centre for Planetary Health and Food Security, Griffith University, Southport, Queensland, 4222, Australia; Faculty of Science and Engineering, Southern Cross University, Lismore, New South Wales, 2480, Australia.
| | - Chantal M Lanctôt
- School of Environment and Science, Griffith University, Southport, Queensland, 4222, Australia; Australian Rivers Institute, Griffith University, Southport, Queensland, 4222, Australia
| | - Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, 14642, Rochester, NY, United States
| | - Hamish I McCallum
- School of Environment and Science, Griffith University, Southport, Queensland, 4222, Australia; Centre for Planetary Health and Food Security, Griffith University, Southport, Queensland, 4222, Australia
| | - David A Newell
- Faculty of Science and Engineering, Southern Cross University, Lismore, New South Wales, 2480, Australia
| | - Laura F Grogan
- School of Environment and Science, Griffith University, Southport, Queensland, 4222, Australia; Centre for Planetary Health and Food Security, Griffith University, Southport, Queensland, 4222, Australia
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9
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Machado C, Cuco AP, Cássio F, Wolinska J, Castro BB. Antiparasitic potential of agrochemical fungicides on a non-target aquatic model (Daphnia × Metschnikowia host-parasite system). THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 833:155296. [PMID: 35429554 DOI: 10.1016/j.scitotenv.2022.155296] [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: 02/06/2022] [Revised: 03/29/2022] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
Pesticides are a major anthropogenic threat to the biodiversity of freshwater ecosystems, having the potential to affect non-target aquatic organisms and disrupt the processes in which they intervene. Important knowledge gaps have been recognised concerning the ecological effects of synthetic fungicides on non-target symbiotic aquatic fungi and the ecological processes where they intervene. The goal of this work was to assess the influence of three commonly used fungicides (myclobutanil, metalaxyl and cymoxanil), which differ in their mode of action, on a host (the crustacean Daphnia magna) × parasite (the yeast Metschnikowia bicuspidata) experimental model. Using a set of life history experiments, we evaluated the effect of each fungicide on the outcome of this relationship (disease) and on the fitness of both host and parasite. Contrasting results were observed: (i) cymoxanil and metalaxyl were overall innocuous to host and parasite at the tested concentrations, although host reproduction was occasionally reduced in the simultaneous presence of parasite and fungicide; (ii) on the contrary, myclobutanil displayed a clear antifungal effect, decreasing parasite prevalence and alleviating infection signs in the hosts. This antiparasitic effect of myclobutanil was further investigated with a follow-up experiment that manipulated the timing of application of the fungicide, to understand which stage of parasite development was most susceptible: while myclobutanil did not interfere in the early stages of infection, its antifungal activity was clearly observable at a later stage of the disease (by impairing the production of transmission stages of the parasite). More research is needed to understand the broader consequences of this parasite-clearance effect, especially in face of increasing evidence that parasites are ecologically more important than their cryptic nature might suggest.
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Affiliation(s)
- Cláudia Machado
- CBMA (Centre of Molecular and Environmental Biology) & Department of Biology, School of Sciences, University of Minho, Braga, Portugal; Institute of Science and Innovation for Bio-Sustainability (IB-S), School of Sciences, University of Minho, Braga, Portugal
| | - Ana P Cuco
- CBMA (Centre of Molecular and Environmental Biology) & Department of Biology, School of Sciences, University of Minho, Braga, Portugal; Institute of Science and Innovation for Bio-Sustainability (IB-S), School of Sciences, University of Minho, Braga, Portugal
| | - Fernanda Cássio
- CBMA (Centre of Molecular and Environmental Biology) & Department of Biology, School of Sciences, University of Minho, Braga, Portugal; Institute of Science and Innovation for Bio-Sustainability (IB-S), School of Sciences, University of Minho, Braga, Portugal
| | - Justyna Wolinska
- Department of Evolutionary and Integrative Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany; Department of Biology, Chemistry, Pharmacy, Institute of Biology, Freie Universität Berlin, Berlin, Germany
| | - Bruno B Castro
- CBMA (Centre of Molecular and Environmental Biology) & Department of Biology, School of Sciences, University of Minho, Braga, Portugal; Institute of Science and Innovation for Bio-Sustainability (IB-S), School of Sciences, University of Minho, Braga, Portugal.
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10
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Haver M, Le Roux G, Friesen J, Loyau A, Vredenburg VT, Schmeller DS. The role of abiotic variables in an emerging global amphibian fungal disease in mountains. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 815:152735. [PMID: 34974000 DOI: 10.1016/j.scitotenv.2021.152735] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 12/23/2021] [Accepted: 12/23/2021] [Indexed: 06/14/2023]
Abstract
The emergence of the chytridiomycete fungal pathogen Batrachochytrium dendrobatidis (Bd), causing the disease chytridiomycosis, has caused collapse of amphibian communities in numerous mountain systems. The health of amphibians and of mountain freshwater habitats they inhabit is also threatened by ongoing changes in environmental and anthropogenic factors such as climate, hydrology, and pollution. Climate change is causing more extreme climatic events, shifts in ice occurrence, and changes in the timing of snowmelt and pollutant deposition cycles. All of these factors impact both pathogen and host, and disease dynamics. Here we review abiotic variables, known to control Bd occurrence and chytridiomycosis severity, and discuss how climate change may modify them. We propose two main categories of abiotic variables that may alter Bd distribution, persistence, and physiology: 1) climate and hydrology (temperature, precipitation, hydrology, ultraviolet radiation (UVR); and, 2) water chemistry (pH, salinity, pollution). For both categories, we identify topics for further research. More studies on the relationship between global change, pollution and pathogens in complex landscapes, such as mountains, are needed to allow for accurate risk assessments for freshwater ecosystems and resulting impacts on wildlife and human health. Our review emphasizes the importance of using data of higher spatiotemporal resolution and uniform abiotic metrics in order to better compare study outcomes. Fine-scale temperature variability, especially of water temperature, variability of moisture conditions and water levels, snow, ice and runoff dynamics should be assessed as abiotic variables shaping the mountain habitat of pathogen and host. A better understanding of hydroclimate and water chemistry variables, as co-factors in disease, will increase our understanding of chytridiomycosis dynamics.
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Affiliation(s)
- Marilen Haver
- Laboratoire Écologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse INP, Université Toulouse 3 - Paul Sabatier (UPS), Toulouse, France.
| | - Gaël Le Roux
- Laboratoire Écologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse INP, Université Toulouse 3 - Paul Sabatier (UPS), Toulouse, France
| | - Jan Friesen
- Environmental and Biotechnology Centre, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Adeline Loyau
- Laboratoire Écologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse INP, Université Toulouse 3 - Paul Sabatier (UPS), Toulouse, France; Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhütte 2, Stechlin D-16775, Germany
| | - Vance T Vredenburg
- Department of Biology, San Francisco State University, 1600 Holloway Ave., San Francisco, CA 94132, USA
| | - Dirk S Schmeller
- Laboratoire Écologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse INP, Université Toulouse 3 - Paul Sabatier (UPS), Toulouse, France
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11
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Brown MK, Haskins DL, Russell AL, Lambert ML, Quick CE, Pilgrim MA, Tuberville TD. Mercury and Radiocesium Accumulation and Associations With Sublethal Endpoints in the Florida Green Watersnake (Nerodia floridana). ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2022; 41:758-770. [PMID: 35112731 DOI: 10.1002/etc.5281] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/28/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
Mercury (Hg) and radiocesium (137 Cs) are well-known environmental contaminants with the potential to impact the health of humans and wildlife. Snakes have several characteristics conducive to studying environmental contamination but have rarely been included in the monitoring of polluted sites. We investigated the bioaccumulation of Hg and 137 Cs and associations with sublethal effects (standard metabolic rate [SMR] and hemoparasite infections) in Florida green watersnakes (Nerodia floridana). We captured 78 snakes from three former nuclear cooling reservoirs on the US Department of Energy's Savannah River Site in South Carolina (USA). For captured snakes, we (1) determined whole-body 137 Cs, (2) quantified total Hg (THg) using snake tail clips, (3) conducted hemoparasite counts, and (4) measured the SMR. We used multiple regression models to determine associations among snake body size, capture location, sex, tail THg, whole-body 137 Cs, Hepatozoon spp. prevalence and parasitemia, and SMR. Average whole-body 137 Cs (0.23 ± 0.08 Becquerels [Bq]/g; range: 0.00-1.02 Bq/g) was correlated with snake body size and differed significantly by capture site (Pond B: 0.67 ± 0.05 Bq/g; Par Pond: 0.10 ± 0.02 Bq/g; Pond 2: 0.03 ± 0.02 Bq/g). Tail THg (0.33 ± 0.03 mg/kg dry wt; range: 0.16-2.10 mg/kg) was significantly correlated with snake body size but did not differ by capture site. We found no clear relationship between SMR and contaminant burdens. However, models indicated that the prevalence of Hepatozoon spp. in snakes was inversely related to increasing whole-body 137 Cs burdens. Our results indicate the bioaccumulation of Hg and 137 Cs in N. floridana and further demonstrate the utility of aquatic snakes as bioindicators. Our results also suggest a decrease in Hepatozoon spp. prevalence related to increased burdens of 137 Cs. Although the results are intriguing, further research is needed to understand the dynamics between 137 Cs and Hepatozoon spp. infections in semiaquatic snakes. Environ Toxicol Chem 2022;41:758-770. © 2022 SETAC.
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Affiliation(s)
- Marty Kyle Brown
- Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina, USA
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, USA
| | - David Lee Haskins
- Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina, USA
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, USA
- Interdisciplinary Toxicology Program, University of Georgia, Athens, Georgia, USA
| | - Amelia L Russell
- Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina, USA
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, USA
| | - Michaela L Lambert
- Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina, USA
- Department of Forestry and Natural Resources, University of Kentucky, Lexington, Kentucky, USA
| | - Caleigh E Quick
- Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina, USA
- College of Environmental Science and Forestry, State University of New York, Syracuse, New York, USA
| | - Melissa A Pilgrim
- Division of Natural Sciences and Engineering, University of South Carolina Upstate, Spartanburg, South Carolina, USA
| | - Tracey D Tuberville
- Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina, USA
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12
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Cable AB, Willcox EV, Leppanen C. Contaminant exposure as an additional stressor to bats affected by white-nose syndrome: current evidence and knowledge gaps. ECOTOXICOLOGY (LONDON, ENGLAND) 2022; 31:12-23. [PMID: 34625892 DOI: 10.1007/s10646-021-02475-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/01/2021] [Indexed: 06/13/2023]
Abstract
Bats are exposed to numerous threats including pollution and emerging diseases. In North America, the fungal disease white-nose syndrome (WNS) has caused declines in many bat species. While the mechanisms of WNS have received considerable research attention, possible influences of contaminants have not. Herein, we review what is known about contaminant exposure and toxicity for four species whose populations have been severely affected by WNS (Myotis sodalis, M. septentrionalis, M. lucifugus, and Perimyotis subflavus) and identify temporal and spatial data gaps. We determine that there is limited information about the effects of contaminants on bats, and many compounds that have been detected in these bat species have yet to be evaluated for toxicity. The four species examined were exposed to a wide variety of contaminants; however, large spatial and knowledge gaps limit our ability to evaluate if contaminants contribute to species-level declines and if contaminant exposure exacerbates infection by WNS.
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Affiliation(s)
- Ashleigh B Cable
- Department of Forestry, Wildlife, and Fisheries, 274 Ellington Plant Sciences, University of Tennessee, Knoxville, TN, 37996-1610, USA
| | - Emma V Willcox
- Department of Forestry, Wildlife, and Fisheries, 274 Ellington Plant Sciences, University of Tennessee, Knoxville, TN, 37996-1610, USA.
| | - Christy Leppanen
- Department of Ecology and Evolutionary Biology, 569 Dabney Hall, University of Tennessee, Knoxville, TN, 37996-1610, USA
- The Center for Tobacco Products, United States Food and Drug Administration, Silver Spring, MD, 20993-0002, USA
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13
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Bosch J, Thumsová B, López-Rojo N, Pérez J, Alonso A, Fisher MC, Boyero L. Microplastics increase susceptibility of amphibian larvae to the chytrid fungus Batrachochytrium dendrobatidis. Sci Rep 2021; 11:22438. [PMID: 34789869 PMCID: PMC8599647 DOI: 10.1038/s41598-021-01973-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 11/08/2021] [Indexed: 11/09/2022] Open
Abstract
Microplastics (MPs), a new class of pollutants that pose a threat to aquatic biodiversity, are of increasing global concern. In tandem, the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) causing the disease chytridiomycosis is emerging worldwide as a major stressor to amphibians. We here assess whether synergies exist between this infectious disease and MP pollution by mimicking natural contact of a highly susceptible species (midwife toads, Alytes obstetricans) with a Bd-infected reservoir species (fire salamanders, Salamandra salamandra) in the presence and absence of MPs. We found that MP ingestion increases the burden of infection by Bd in a dose-dependent manner. However, MPs accumulated to a greater extent in amphibians that were not exposed to Bd, likely due to Bd-damaged tadpole mouthparts interfering with MP ingestion. Our experimental approach showed compelling interactions between two emergent processes, chytridiomycosis and MP pollution, necessitating further research into potential synergies between these biotic and abiotic threats to amphibians.
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Affiliation(s)
- Jaime Bosch
- Biodiversity Research Institute, University of Oviedo-Principality of Asturias-CSIC, Mieres, Spain. .,Centro de Investigación, Seguimiento y Evaluación, Parque Nacional Sierra de Guadarrama, Rascafría, Spain. .,Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain.
| | - Barbora Thumsová
- Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain.,Asociación Herpetológica Española, Madrid, Spain
| | - Naiara López-Rojo
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Leioa, Spain.,Laboratoire d'Ecologie Alpine (LECA), Université Grenoble Alpes, UMR CNRS-UGA-USMB, Grenoble, France
| | - Javier Pérez
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Alberto Alonso
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Matthew C Fisher
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial School of Public Health, London, UK
| | - Luz Boyero
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Leioa, Spain.,IKERBASQUE, Bilbao, Spain
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14
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Preuss JF, Greenspan SE, Rossi EM, Lucas Gonsales EM, Neely WJ, Valiati VH, Woodhams DC, Becker CG, Tozetti AM. Widespread Pig Farming Practice Linked to Shifts in Skin Microbiomes and Disease in Pond-Breeding Amphibians. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:11301-11312. [PMID: 32845628 DOI: 10.1021/acs.est.0c03219] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Farming practices may reshape the structure of watersheds, water quality, and the health of aquatic organisms. Nutrient enrichment from agricultural pollution increases disease pressure in many host-pathogen systems, but the mechanisms underlying this pattern are not always resolved. For example, nutrient enrichment should strongly influence pools of aquatic environmental bacteria, which has the potential to alter microbiome composition of aquatic animals and their vulnerability to disease. However, shifts in the host microbiome have received little attention as a link between nutrient enrichment and diseases of aquatic organisms. We examined nutrient enrichment through the widespread practice of integrated pig-fish farming and its effects on microbiome composition of Brazilian amphibians and prevalence of the globally distributed amphibian skin pathogen Batrachochytrium dendrobatidis (Bd). This farming system drove surges in fecal coliform bacteria, disturbing amphibian skin bacterial communities such that hosts recruited higher proportions of Bd-facilitative bacteria and carried higher Bd prevalence. Our results highlight previously overlooked connections between global trends in land use change, microbiome dysbiosis, and wildlife disease. These interactions may be particularly important for disease management in the tropics, a region with both high biodiversity and continually intensifying anthropogenic pressures on aquatic wildlife habitats.
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Affiliation(s)
- Jackson F Preuss
- Programa de Pós-Graduação em Biologia, Universidade do Vale do Rio dos Sinos, São Leopoldo, RS 93022-750, Brazil
- Departamento de Ciências da Vida, Universidade do Oeste de Santa Catarina, São Miguel do Oeste, SC 89900-000, Brazil
| | - Sasha E Greenspan
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Eliandra M Rossi
- Departamento de Ciências da Vida, Universidade do Oeste de Santa Catarina, São Miguel do Oeste, SC 89900-000, Brazil
| | - Elaine M Lucas Gonsales
- Departamento de Zootecnia e Ciências Biológicas, Universidade Federal de Santa Maria, RS 98300-000, Brazil
| | - Wesley J Neely
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Victor Hugo Valiati
- Programa de Pós-Graduação em Biologia, Universidade do Vale do Rio dos Sinos, São Leopoldo, RS 93022-750, Brazil
| | - Douglas C Woodhams
- Department of Biology, University of Massachusetts Boston, Boston, Massachusetts 02125, United States
| | - C Guilherme Becker
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Alexandro M Tozetti
- Programa de Pós-Graduação em Biologia, Universidade do Vale do Rio dos Sinos, São Leopoldo, RS 93022-750, Brazil
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15
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Bienentreu JF, Lesbarrères D. Amphibian Disease Ecology: Are We Just Scratching the Surface? HERPETOLOGICA 2020. [DOI: 10.1655/0018-0831-76.2.153] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | - David Lesbarrères
- Department of Biology, Laurentian University, Sudbury, ON P3E 2C6, Canada
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16
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Clay TA, Steffen MA, Treglia ML, Torres CD, Trujano-Alvarez AL, Bonett RM. Multiple stressors produce differential transcriptomic patterns in a stream-dwelling salamander. BMC Genomics 2019; 20:482. [PMID: 31185901 PMCID: PMC6560913 DOI: 10.1186/s12864-019-5814-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 05/20/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Global biodiversity is decreasing at an alarming rate and amphibians are at the forefront of this crisis. Understanding the factors that negatively impact amphibian populations and effectively monitoring their health are fundamental to addressing this epidemic. Plasma glucocorticoids are often used to assess stress in amphibians and other vertebrates, but these hormones can be extremely dynamic and impractical to quantify in small organisms. Transcriptomic responses to stress hormones in amphibians have been largely limited to laboratory models, and there have been few studies on vertebrates that have evaluated the impact of multiple stressors on patterns of gene expression. Here we examined the gene expression patterns in tail tissues of stream-dwelling salamanders (Eurycea tynerensis) chronically exposed to the stress hormone corticosterone under different temperature regimes. RESULTS We found unique transcriptional signatures for chronic corticosterone exposure that were independent of temperature variation. Several of the corticosterone responsive genes are known to be involved in immune system response (LY-6E), oxidative stress (GSTM2 and TRX), and tissue repair (A2M and FX). We also found many genes to be influenced by temperature (CIRBP, HSC71, HSP40, HSP90, HSP70, ZNF593). Furthermore, the expression patterns of some genes (GSTM2, LY-6E, UMOD, ZNF593, CIRBP, HSP90) show interactive effects of temperature and corticosterone exposure, compared to each treatment alone. Through a series of experiments we also showed that stressor induced patterns of expression were largely consistent across ages, life cycle modes, and tissue regeneration. CONCLUSIONS Outside of thermal stressors, the application of transcriptomes to monitor the health of non-human vertebrate systems has been vastly underinvestigated. Our study suggests that transcriptomic patterns harbor stressor specific signatures that can be highly informative for monitoring the diverse stressors of amphibian populations.
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Affiliation(s)
- Timothy A Clay
- Department of Biological Science, University of Tulsa, Tulsa, OK, 74104, USA. .,Present Address: Department of Biological Sciences, Nicholls State University, Thibodaux, LA, 70310, USA.
| | - Michael A Steffen
- Department of Biological Science, University of Tulsa, Tulsa, OK, 74104, USA.,Present Address: Department of Biological Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Michael L Treglia
- Department of Biological Science, University of Tulsa, Tulsa, OK, 74104, USA.,Present Address: The Nature Conservancy, New York, NY, 10001, USA
| | - Carolyn D Torres
- Department of Biological Science, University of Tulsa, Tulsa, OK, 74104, USA
| | | | - Ronald M Bonett
- Department of Biological Science, University of Tulsa, Tulsa, OK, 74104, USA.
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17
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Effects of Emerging Infectious Diseases on Amphibians: A Review of Experimental Studies. DIVERSITY-BASEL 2018. [DOI: 10.3390/d10030081] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Numerous factors are contributing to the loss of biodiversity. These include complex effects of multiple abiotic and biotic stressors that may drive population losses. These losses are especially illustrated by amphibians, whose populations are declining worldwide. The causes of amphibian population declines are multifaceted and context-dependent. One major factor affecting amphibian populations is emerging infectious disease. Several pathogens and their associated diseases are especially significant contributors to amphibian population declines. These include the fungi Batrachochytrium dendrobatidis and B. salamandrivorans, and ranaviruses. In this review, we assess the effects of these three pathogens on amphibian hosts as found through experimental studies. Such studies offer valuable insights to the causal factors underpinning broad patterns reported through observational studies. We summarize key findings from experimental studies in the laboratory, in mesocosms, and from the field. We also summarize experiments that explore the interactive effects of these pathogens with other contributors of amphibian population declines. Though well-designed experimental studies are critical for understanding the impacts of disease, inconsistencies in experimental methodologies limit our ability to form comparisons and conclusions. Studies of the three pathogens we focus on show that host susceptibility varies with such factors as species, host age, life history stage, population and biotic (e.g., presence of competitors, predators) and abiotic conditions (e.g., temperature, presence of contaminants), as well as the strain and dose of the pathogen, to which hosts are exposed. Our findings suggest the importance of implementing standard protocols and reporting for experimental studies of amphibian disease.
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18
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Cuco AP, Santos JI, Abrantes N, Gonçalves F, Wolinska J, Castro BB. Concentration and timing of application reveal strong fungistatic effect of tebuconazole in a Daphnia-microparasitic yeast model. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2017; 193:144-151. [PMID: 29096087 DOI: 10.1016/j.aquatox.2017.10.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 10/06/2017] [Accepted: 10/19/2017] [Indexed: 06/07/2023]
Abstract
Given the importance of pollutant effects on host-parasite relationships and disease spread, the main goal of this study was to assess the influence of different exposure scenarios for the fungicide tebuconazole (concentration×timing of application) on a Daphnia-microparasitic yeast experimental system. Previous results had demonstrated that tebuconazole is able to suppress Metschnikowia bicuspidata infection at ecologically-relevant concentrations; here, we aimed to obtain an understanding of the mechanism underlying the anti-parasitic (fungicidal or fungistatic) action of tebuconazole. We exposed the Daphnia-yeast system to four nominal tebuconazole concentrations at four timings of application (according to the predicted stage of parasite development), replicated on two Daphnia genotypes, in a fully crossed experiment. An "all-or-nothing" effect was observed, with tebuconazole completely suppressing infection from 13.5μgl-1 upwards, independent of the timing of tebuconazole application. A follow-up experiment confirmed that the suppression of infection occurred within a narrow range of tebuconazole concentrations (3.65-13.5μgl-1), although a later application of the fungicide had to be compensated for by a slight increase in concentration to elicit the same anti-parasitic effect. The mechanism behind this anti-parasitic effect seems to be the inhibition of M. bicuspidata sporulation, since tebuconazole was effective in preventing ascospore production even when applied at a later time. However, this fungicide also seemed to affect the vegetative growth of the yeast, as demonstrated by the enhanced negative effect of the parasite (increasing mortality in one of the host genotypes) at a later time of application of tebuconazole, when no signs of infection were observed. Fungicide contamination can thus affect the severity and spread of disease in natural populations, as well as the inherent co-evolutionary dynamics in host-parasite systems.
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Affiliation(s)
- Ana P Cuco
- Department of Biology, University of Aveiro, Aveiro, Portugal; CESAM, University of Aveiro, Aveiro, Portugal.
| | - Joana I Santos
- Department of Biology, University of Aveiro, Aveiro, Portugal; CESAM, University of Aveiro, Aveiro, Portugal
| | - Nelson Abrantes
- CESAM, University of Aveiro, Aveiro, Portugal; Department of Environment and Planning, University of Aveiro, Aveiro, Portugal
| | - Fernando Gonçalves
- Department of Biology, University of Aveiro, Aveiro, Portugal; CESAM, University of Aveiro, Aveiro, Portugal
| | - Justyna Wolinska
- Department of Ecosystem Research, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany; Department of Biology, Chemistry, Pharmacy, Institute of Biology, Freie Universität Berlin, Berlin, Germany
| | - Bruno B Castro
- CBMA (Centre of Molecular and Environmental Biology), Department of Biology, University of Minho, Braga, Portugal
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Garner TWJ, Schmidt BR, Martel A, Pasmans F, Muths E, Cunningham AA, Weldon C, Fisher MC, Bosch J. Mitigating amphibian chytridiomycoses in nature. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2016.0207. [PMID: 28080996 DOI: 10.1098/rstb.2016.0207] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2016] [Indexed: 12/11/2022] Open
Abstract
Amphibians across the planet face the threat of population decline and extirpation caused by the disease chytridiomycosis. Despite consensus that the fungal pathogens responsible for the disease are conservation issues, strategies to mitigate their impacts in the natural world are, at best, nascent. Reducing risk associated with the movement of amphibians, non-amphibian vectors and other sources of infection remains the first line of defence and a primary objective when mitigating the threat of disease in wildlife. Amphibian-associated chytridiomycete fungi and chytridiomycosis are already widespread, though, and we therefore focus on discussing options for mitigating the threats once disease emergence has occurred in wild amphibian populations. All strategies have shortcomings that need to be overcome before implementation, including stronger efforts towards understanding and addressing ethical and legal considerations. Even if these issues can be dealt with, all currently available approaches, or those under discussion, are unlikely to yield the desired conservation outcome of disease mitigation. The decision process for establishing mitigation strategies requires integrated thinking that assesses disease mitigation options critically and embeds them within more comprehensive strategies for the conservation of amphibian populations, communities and ecosystems.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'.
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Affiliation(s)
- Trenton W J Garner
- Institute of Zoology, Zoological Society of London, Regents Park, NW1 4RY London, UK .,Unit for Environmental Research and Management, North-West University, Potchefstroom 2520, South Africa
| | - Benedikt R Schmidt
- Karch, Passage Maximilien-de-Meuron 6, 2000 Neuchâtel, Switzerland.,Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Erin Muths
- U.S. Geological Survey, Fort Collins Science Fort Collins, 2150 Centre Avenue Building C, Fort Collins, CO 80526, USA
| | - Andrew A Cunningham
- Institute of Zoology, Zoological Society of London, Regents Park, NW1 4RY London, UK
| | - Che Weldon
- Unit for Environmental Research and Management, North-West University, Potchefstroom 2520, South Africa
| | - Matthew C Fisher
- Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Jaime Bosch
- Museo Nacional de Ciencias Naturales, CSIC, José Gutiérrez Abascal 2, 28006 Madrid, Spain
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20
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Rodeo™ Herbicide Negatively Affects Blanchard's Cricket Frogs (Acris blanchardi) Survival and Alters the Skin-Associated Bacterial Community. J HERPETOL 2017. [DOI: 10.1670/16-092] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Mikó Z, Ujszegi J, Hettyey A. Age-dependent changes in sensitivity to a pesticide in tadpoles of the common toad (Bufo bufo). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2017; 187:48-54. [PMID: 28365461 DOI: 10.1016/j.aquatox.2017.03.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/17/2017] [Accepted: 03/19/2017] [Indexed: 06/07/2023]
Abstract
The worldwide en masse application of pesticides and the frequently reported malign effects on several non-target organisms underpin the importance of ecotoxicological research on these anthropogenic pollutants. Previous studies showed that sensitivity to herbicides can vary widely depending on additional stress factors, on the species and even on the population investigated. However, there is little information about how sensitivity changes during ontogeny, and how the duration of exposure is linked to the magnitude of malign effects, even though this knowledge would be important for the interpretation of toxicity test results and for formulating recommendations regarding the timing of pesticide application. We exposed tadpoles of the common toad (Bufo bufo) to three concentrations (0, 2 and 4mg a.e./L) of a glyphosate-based herbicide during the 1st, 2nd, 3rd, 4th, or 5th period of larval development or during the entire experiment, and measured survival, time until metamorphosis and body mass at metamorphosis to estimate fitness-consequences. Younger tadpoles were more sensitive to the herbicide in all measured traits than older ones, and this age-dependence was especially pronounced at the high herbicide concentration. Furthermore, tadpoles exposed to the herbicide during the entire experiment developed slower than tadpoles exposed only early on, but we did not observe a similar effect either on body mass or survival. The observed age-dependence of sensitivity to herbicides draws attention to the fact that results of toxicity tests obtained for one age-class are not necessarily generalizable across ontogeny. Also, the age of test animals has to be considered when planning ecotoxicological studies and interpreting their results. Finally, taking into account the temporal breeding habits of local amphibians when planning pesticide application would be highly favourable: if tadpoles would not get exposed to the herbicide during their most sensitive early development, they would sustain less anthropogenic damage from our efforts of controlling weeds.
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Affiliation(s)
- Zsanett Mikó
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest 1022, Hungary.
| | - János Ujszegi
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest 1022, Hungary; Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest 1117, Hungary
| | - Attila Hettyey
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest 1022, Hungary
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22
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Romansic JM, Johnson JE, Wagner RS, Hill RH, Gaulke CA, Vredenburg VT, Blaustein AR. Complex interactive effects of water mold, herbicide, and the fungus Batrachochytrium dendrobatidis on Pacific treefrog Hyliola regilla hosts. DISEASES OF AQUATIC ORGANISMS 2017; 123:227-238. [PMID: 28322209 DOI: 10.3354/dao03094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Infectious diseases pose a serious threat to global biodiversity. However, their ecological impacts are not independent of environmental conditions. For example, the pathogenic fungus Batrachochytrium dendrobatidis (Bd), which has contributed to population declines and extinctions in many amphibian species, interacts with several environmental factors to influence its hosts, but potential interactions with other pathogens and environmental contaminants are understudied. We examined the combined effects of Bd, a water mold (Achlya sp.), and the herbicide Roundup® Regular (hereafter, Roundup®) on larval Pacific treefrog Hyliola regilla hosts. We employed a 2 wk, fully factorial laboratory experiment with 3 ecologically realistic levels (0, 1, and 2 mg l-1 of active ingredient) of field-formulated Roundup®, 2 Achlya treatments (present and absent), and 2 Bd treatments (present and absent). Our results were consistent with sublethal interactive effects involving all 3 experimental factors. When Roundup® was absent, the proportion of Bd-exposed larvae infected with Bd was elevated in the presence of Achlya, consistent with Achlya acting as a synergistic cofactor that facilitated the establishment of Bd infection. However, this Achlya effect became nonsignificant at 1 mg l-1 of the active ingredient of Roundup® and disappeared at the highest Roundup® concentration. In addition, Roundup® decreased Bd loads among Bd-exposed larvae. Our study suggests complex interactive effects of a water mold and a contaminant on Bd infection in amphibian hosts. Achlya and Roundup® were both correlated with altered patterns of Bd infection, but in different ways, and Roundup® appeared to remove the influence of Achlya on Bd.
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Affiliation(s)
- John M Romansic
- Department of Integrative Biology, 3029 Cordley Hall, Oregon State University, Corvallis, Oregon 97331, USA
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Jones DK, Dang TD, Urbina J, Bendis RJ, Buck JC, Cothran RD, Blaustein AR, Relyea RA. Effect of Simultaneous Amphibian Exposure to Pesticides and an Emerging Fungal Pathogen, Batrachochytrium dendrobatidis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:671-679. [PMID: 28001054 DOI: 10.1021/acs.est.6b06055] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Amphibian declines have been linked to numerous factors, including pesticide use and the fungal pathogen Batrachochytrium dendrobatidis (Bd). Moreover, research has suggested a link between amphibian sensitivity to Bd and pesticide exposure. We simultaneously exposed postmetamorphic American toads (Anaxyrus americanus), western toads (A. boreas), spring peepers (Pseudacris crucifer), Pacific treefrogs (P. regilla), leopard frogs (Lithobates pipiens), and Cascades frogs (Rana cascadae) to a factorial combination of two pathogen treatments (Bd+, Bd-) and four pesticide treatments (control, ethanol vehicle, herbicide mixture, and insecticide mixture) for 14 d to quantify survival and infection load. We found no interactive effects of pesticides and Bd on anuran survival and no effects of pesticides on infection load. Mortality following Bd exposure increased in spring peepers and American toads and was dependent upon snout-vent length in western toads, American toads, and Pacific treefrogs. Previous studies reported effects of early sublethal pesticide exposure on amphibian Bd sensitivity and infection load at later life stages, but we found simultaneous exposure to sublethal pesticide concentrations and Bd had no such effect on postmetamorphic juvenile anurans. Future research investigating complex interactions between pesticides and Bd should employ a variety of pesticide formulations and Bd strains and follow the effects of exposure throughout ontogeny.
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Affiliation(s)
- Devin K Jones
- Department of Biological Sciences, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
| | | | | | - Randall J Bendis
- Department of Biological Sciences, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
| | - Julia C Buck
- Marine Science Institute, University of California Santa Barbara , Santa Barbara, California 93106, United States
| | - Rickey D Cothran
- Department of Biological Sciences, Southwestern Oklahoma State University , Weatherford, Oklahoma 73096, United States
| | | | - Rick A Relyea
- Department of Biological Sciences, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
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24
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Battaglin WA, Smalling KL, Anderson C, Calhoun D, Chestnut T, Muths E. Potential interactions among disease, pesticides, water quality and adjacent land cover in amphibian habitats in the United States. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 566-567:320-332. [PMID: 27232962 DOI: 10.1016/j.scitotenv.2016.05.062] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 05/06/2016] [Accepted: 05/06/2016] [Indexed: 05/21/2023]
Abstract
To investigate interactions among disease, pesticides, water quality, and adjacent land cover, we collected samples of water, sediment, and frog tissue from 21 sites in 7 States in the United States (US) representing a variety of amphibian habitats. All samples were analyzed for >90 pesticides and pesticide degradates, and water and frogs were screened for the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) using molecular methods. Pesticides and pesticide degradates were detected frequently in frog breeding habitats (water and sediment) as well as in frog tissue. Fungicides occurred more frequently in water, sediment, and tissue than was expected based upon their limited use relative to herbicides or insecticides. Pesticide occurrence in water or sediment was not a strong predictor of occurrence in tissue, but pesticide concentrations in tissue were correlated positively to agricultural and urban land, and negatively to forested land in 2-km buffers around the sites. Bd was detected in water at 45% of sites, and on 34% of swabbed frogs. Bd detections in water were not associated with differences in land use around sites, but sites with detections had colder water. Frogs that tested positive for Bd were associated with sites that had higher total fungicide concentrations in water and sediment, but lower insecticide concentrations in sediments relative to frogs that were Bd negative. Bd concentrations on frog swabs were positively correlated to dissolved organic carbon, and total nitrogen and phosphorus, and negatively correlated to pH and water temperature. Data were collected from a range of locations and amphibian habitats and represent some of the first field-collected information aimed at understanding the interactions between pesticides, land use, and amphibian disease. These interactions are of particular interest to conservation efforts as many amphibians live in altered habitats and may depend on wetlands embedded in these landscapes to survive.
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Affiliation(s)
- W A Battaglin
- U.S. Geological Survey, Colorado Water Science Center, Lakewood, CO, United States
| | - K L Smalling
- U.S. Geological Survey, New Jersey Water Science Center, Lawrenceville, NJ, United States
| | - C Anderson
- U.S. Geological Survey, Oregon Water Science Center, Portland, OR, United States
| | - D Calhoun
- U.S. Geological Survey South Atlantic Water Science Center, Atlanta, GA, United States
| | - T Chestnut
- National Park Service, Mount Rainer National Park, Ashford, WA, United States
| | - E Muths
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, CO, United States
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25
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Strong RJ, Halsall CJ, Jones KC, Shore RF, Martin FL. Infrared spectroscopy detects changes in an amphibian cell line induced by fungicides: Comparison of single and mixture effects. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 178:8-18. [PMID: 27450236 DOI: 10.1016/j.aquatox.2016.07.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 05/24/2016] [Accepted: 07/13/2016] [Indexed: 06/06/2023]
Abstract
Amphibians are regarded as sensitive sentinels of environmental pollution due to their permeable skin and complex life cycle, which usually involves reproduction and development in the aquatic environment. Fungicides are widely applied agrochemicals and have been associated with developmental defects in amphibians; thus, it is important to determine chronic effects of environmentally-relevant concentrations of such contaminants in target cells. Infrared (IR) spectroscopy has been employed to signature the biological effects of environmental contaminants through extracting key features in IR spectra with chemometric methods. Herein, the Xenopus laevis (A6) cell line was exposed to low concentrations of carbendazim (a benzimidazole fungicide) or flusilazole (a triazole fungicide) either singly or as a binary mixture. Cells were then examined using attenuated total reflection Fourier-transform IR (ATR-FTIR) spectroscopy coupled with multivariate analysis. Results indicate significant changes in the IR spectra of cells induced by both agents at all concentrations following single exposures, primarily in regions associated with protein and phospholipids. Distinct differences were apparent in the IR spectra of cells exposed to carbendazim and those exposed to flusilazole, suggesting different mechanisms of action. Exposure to binary mixtures of carbendazim and flusilazole also induced significant spectral alterations, again in regions associated with phospholipids and proteins, but also in regions associated with DNA and carbohydrates. Overall these findings demonstrate that IR spectroscopy is a sensitive technique for examining the effects of environmentally-relevant levels of fungicides at the cellular level. The combination of IR spectroscopy with the A6 cell line could serve as a useful model to identify agents that might threaten amphibian health in a rapid and high throughput manner.
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Affiliation(s)
- Rebecca J Strong
- Lancaster Environment Centre, Lancaster University, Bailrigg, Lancaster LA1 4YQ, UK
| | - Crispin J Halsall
- Lancaster Environment Centre, Lancaster University, Bailrigg, Lancaster LA1 4YQ, UK.
| | - Kevin C Jones
- Lancaster Environment Centre, Lancaster University, Bailrigg, Lancaster LA1 4YQ, UK
| | - Richard F Shore
- Centre for Ecology and Hydrology, Lancaster University, Bailrigg, Lancaster LA1 4YQ, UK
| | - Francis L Martin
- Lancaster Environment Centre, Lancaster University, Bailrigg, Lancaster LA1 4YQ, UK; School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston PR1 2HE, UK.
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26
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James TY, Toledo LF, Rödder D, da Silva Leite D, Belasen AM, Betancourt-Román CM, Jenkinson TS, Soto-Azat C, Lambertini C, Longo AV, Ruggeri J, Collins JP, Burrowes PA, Lips KR, Zamudio KR, Longcore JE. Disentangling host, pathogen, and environmental determinants of a recently emerged wildlife disease: lessons from the first 15 years of amphibian chytridiomycosis research. Ecol Evol 2015; 5:4079-97. [PMID: 26445660 PMCID: PMC4588650 DOI: 10.1002/ece3.1672] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 07/25/2015] [Indexed: 12/18/2022] Open
Abstract
The amphibian fungal disease chytridiomycosis, which affects species across all continents, recently emerged as one of the greatest threats to biodiversity. Yet, many aspects of the basic biology and epidemiology of the pathogen, Batrachochytrium dendrobatidis (Bd), are still unknown, such as when and from where did Bd emerge and what is its true ecological niche? Here, we review the ecology and evolution of Bd in the Americas and highlight controversies that make this disease so enigmatic. We explore factors associated with variance in severity of epizootics focusing on the disease triangle of host susceptibility, pathogen virulence, and environment. Reevaluating the causes of the panzootic is timely given the wealth of data on Bd prevalence across hosts and communities and the recent discoveries suggesting co-evolutionary potential of hosts and Bd. We generate a new species distribution model for Bd in the Americas based on over 30,000 records and suggest a novel future research agenda. Instead of focusing on pathogen "hot spots," we need to identify pathogen "cold spots" so that we can better understand what limits the pathogen's distribution. Finally, we introduce the concept of "the Ghost of Epizootics Past" to discuss expected patterns in postepizootic host communities.
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Affiliation(s)
- Timothy Y James
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan 48109
| | - L Felipe Toledo
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB) Departamento de Biologia Animal Instituto de Biologia Universidade Estadual de Campinas Caixa Postal 6109 Campinas São Paulo CEP 13083-863 Brazil
| | - Dennis Rödder
- Section of Herpetology Zoologisches Forschungsmuseum Alexander Koenig Adenauerallee 160 53113 Bonn Germany
| | - Domingos da Silva Leite
- Laboratório de Antígenos Bacterianos II Departamento de Genética, Evolução e Bioagentes Instituto de Biologia Universidade Estadual de Campinas Caixa Postal 6109 Campinas São Paulo CEP 13083-862 Brazil
| | - Anat M Belasen
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan 48109
| | | | - Thomas S Jenkinson
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan 48109
| | - Claudio Soto-Azat
- Centro de Investigación para la Sustentabilidad Facultad de Ecología y Recursos Naturales, Universidad Andres Bello Santiago Chile
| | - Carolina Lambertini
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB) Departamento de Biologia Animal Instituto de Biologia Universidade Estadual de Campinas Caixa Postal 6109 Campinas São Paulo CEP 13083-863 Brazil
| | - Ana V Longo
- Department of Ecology and Evolutionary Biology Cornell University Ithaca New York 14853
| | - Joice Ruggeri
- Departamento de Zoologia Laboratório de Anfíbios e Répteis Universidade Federal do Rio de Janeiro, Instituto de Biologia Ilha do Fundão, Caixa postal: 68044 Rio de Janeiro RJ CEP 21941-590 Brazil
| | - James P Collins
- School of Life Sciences Arizona State University PO Box 874501 Tempe Arizona 85287-4501
| | | | - Karen R Lips
- Department of Biology University of Maryland College Park Maryland 20901
| | - Kelly R Zamudio
- Department of Ecology and Evolutionary Biology Cornell University Ithaca New York 14853
| | - Joyce E Longcore
- School of Biology and Ecology University of Maine Orono Maine 04469-5722
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27
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Hanlon SM, Lynch KJ, Kerby JL, Parris MJ. The effects of a fungicide and chytrid fungus on anuran larvae in aquatic mesocosms. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:12929-12940. [PMID: 25913318 DOI: 10.1007/s11356-015-4566-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 04/19/2015] [Indexed: 06/04/2023]
Abstract
The amphibian disease chytridiomycosis, caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd), has been linked to significant amphibian declines over the past three decades. The most severe effects of the pathogen have been primarily observed in relatively pristine areas that are not affected by many anthropogenic factors.One hypothesis concerning improved amphibian persistence with Bd in disturbed landscapes is that contaminants may abate the effects of Bd on amphibians. Recent laboratory studies have shown that pesticides, specifically the fungicide thiophanate-methyl (TM), can kill Bd outside of hosts and clear Bd infections within hosts. Using aquatic mesocosms, we tested the hypothesis that TM (0.43 mg/L) would alter growth and development of Lithobates sphenocephalus (southern leopard frog) tadpoles and Bd-infection loads in infected individuals. We hypothesized that the scope of such alterations and infection clearing would be affected by aquatic community variables, specifically zooplankton. TM altered zooplankton diversity (reduced cladoceran and increased copepod and ostracod abundances) and caused mortality to all tadpoles in TM-exposed tanks. In TM-free tanks, Bd-exposed tadpoles in high-density treatments metamorphosed smaller than Bd-unexposed, effects that were reversed in low-density treatments. Our study demonstrates the potential adverse effects of a fungicide and Bd on tadpoles and aquatic systems.
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Affiliation(s)
- Shane M Hanlon
- Department of Biological Sciences, University of Memphis, Memphis, TN, 38152, USA,
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28
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Buck JC, Hua J, Brogan WR, Dang TD, Urbina J, Bendis RJ, Stoler AB, Blaustein AR, Relyea RA. Effects of Pesticide Mixtures on Host-Pathogen Dynamics of the Amphibian Chytrid Fungus. PLoS One 2015; 10:e0132832. [PMID: 26181492 PMCID: PMC4504700 DOI: 10.1371/journal.pone.0132832] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 06/19/2015] [Indexed: 01/22/2023] Open
Abstract
Anthropogenic and natural stressors often interact to affect organisms. Amphibian populations are undergoing unprecedented declines and extinctions with pesticides and emerging infectious diseases implicated as causal factors. Although these factors often co-occur, their effects on amphibians are usually examined in isolation. We hypothesized that exposure of larval and metamorphic amphibians to ecologically relevant concentrations of pesticide mixtures would increase their post-metamorphic susceptibility to the fungus Batrachochytrium dendrobatidis (Bd), a pathogen that has contributed to amphibian population declines worldwide. We exposed five anuran species (Pacific treefrog, Pseudacris regilla; spring peeper, Pseudacris crucifer; Cascades frog, Rana cascadae; northern leopard frog, Lithobates pipiens; and western toad, Anaxyrus boreas) from three families to mixtures of four common insecticides (chlorpyrifos, carbaryl, permethrin, and endosulfan) or herbicides (glyphosate, acetochlor, atrazine, and 2,4-D) or a control treatment, either as tadpoles or as newly metamorphic individuals (metamorphs). Subsequently, we exposed animals to Bd or a control inoculate after metamorphosis and compared survival and Bd load. Bd exposure significantly increased mortality in Pacific treefrogs, spring peepers, and western toads, but not in Cascades frogs or northern leopard frogs. However, the effects of pesticide exposure on mortality were negligible, regardless of the timing of exposure. Bd load varied considerably across species; Pacific treefrogs, spring peepers, and western toads had the highest loads, whereas Cascades frogs and northern leopard frogs had the lowest loads. The influence of pesticide exposure on Bd load depended on the amphibian species, timing of pesticide exposure, and the particular pesticide treatment. Our results suggest that exposure to realistic pesticide concentrations has minimal effects on Bd-induced mortality, but can alter Bd load. This result could have broad implications for risk assessment of amphibians; the outcome of exposure to multiple stressors may be unpredictable and can differ between species and life stages.
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Affiliation(s)
- Julia C. Buck
- Texas Research Institute for Environmental Studies, Sam Houston State University, Huntsville, Texas, United States of America
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
| | - Jessica Hua
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - William R. Brogan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Trang D. Dang
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
| | - Jenny Urbina
- Environmental Sciences Graduate Program, Oregon State University, Corvallis, Oregon, United States of America
| | - Randall J. Bendis
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Aaron B. Stoler
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Andrew R. Blaustein
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
- Environmental Sciences Graduate Program, Oregon State University, Corvallis, Oregon, United States of America
| | - Rick A. Relyea
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
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29
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Burggren WW, Mueller CA. Developmental Critical Windows and Sensitive Periods as Three-Dimensional Constructs in Time and Space. Physiol Biochem Zool 2015; 88:91-102. [DOI: 10.1086/679906] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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30
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Mueller CA, Eme J, Burggren WW, Roghair RD, Rundle SD. Challenges and opportunities in developmental integrative physiology. Comp Biochem Physiol A Mol Integr Physiol 2015; 184:113-24. [PMID: 25711780 DOI: 10.1016/j.cbpa.2015.02.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 02/15/2015] [Accepted: 02/17/2015] [Indexed: 01/20/2023]
Abstract
This review explores challenges and opportunities in developmental physiology outlined by a symposium at the 2014 American Physiological Society Intersociety Meeting: Comparative Approaches to Grand Challenges in Physiology. Across animal taxa, adverse embryonic/fetal environmental conditions can alter morphological and physiological phenotypes in juveniles or adults, and capacities for developmental plasticity are common phenomena. Human neonates with body sizes at the extremes of perinatal growth are at an increased risk of adult disease, particularly hypertension and cardiovascular disease. There are many rewarding areas of current and future research in comparative developmental physiology. We present key mechanisms, models, and experimental designs that can be used across taxa to investigate patterns in, and implications of, the development of animal phenotypes. Intraspecific variation in the timing of developmental events can be increased through developmental plasticity (heterokairy), and could provide the raw material for selection to produce heterochrony--an evolutionary change in the timing of developmental events. Epigenetics and critical windows research recognizes that in ovo or fetal development represent a vulnerable period in the life history of an animal, when the developing organism may be unable to actively mitigate environmental perturbations. 'Critical windows' are periods of susceptibility or vulnerability to environmental or maternal challenges, periods when recovery from challenge is possible, and periods when the phenotype or epigenome has been altered. Developmental plasticity may allow survival in an altered environment, but it also has possible long-term consequences for the animal. "Catch-up growth" in humans after the critical perinatal window has closed elicits adult obesity and exacerbates a programmed hypertensive phenotype (one of many examples of "fetal programing"). Grand challenges for developmental physiology include integrating variation in developmental timing within and across generations, applying multiple stressor dosages and stressor exposure at different developmental timepoints, assessment of epigenetic and parental influences, developing new animal models and techniques, and assessing and implementing these designs and models in human health and development.
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Affiliation(s)
- C A Mueller
- Department of Biology, McMaster University, 1280 Main St. West, Hamilton, ON L8S 4K1, Canada.
| | - J Eme
- Department of Biology, McMaster University, 1280 Main St. West, Hamilton, ON L8S 4K1, Canada.
| | - W W Burggren
- Department of Biological Sciences, University of North Texas, 1155 Union Circle #305220, Denton, TX 76203, USA.
| | - R D Roghair
- Stead Family Department of Pediatrics, University of Iowa, 1270 CBRB JPP, Iowa City, IA 52242, USA.
| | - S D Rundle
- Marine Biology and Ecology Research Centre, Plymouth University, 611 Davy Building Drake Circus, Plymouth, Devon PL4 8AA, UK.
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31
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Hanlon SM, Lynch KJ, Kerby J, Parris MJ. Batrachochytrium dendrobatidis exposure effects on foraging efficiencies and body size in anuran tadpoles. DISEASES OF AQUATIC ORGANISMS 2015; 112:237-242. [PMID: 25590774 DOI: 10.3354/dao02810] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Chytridiomycosis, the amphibian disease caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd), is fatal to adults of many species. Bd is largely sublethal to amphibian larvae; however, it is known to reduce larval (i.e. tadpole) growth rates, with possible long-term effects on population dynamics and fitness. We conducted an experiment to test how Bd altered southern leopard frog Lithobates sphenocephalus tadpole mouthpart damage, percentage of food ingested, and subsequent body size. We examined our results using path analyses. We hypothesized that Bd would increase mouthpart damage, causing less food to be ingested, and ultimately reduce body size. In our model, both Bd exposure and increased mouthpart damage significantly reduced food ingested and subsequent body size. However, our study provides evidence against the long-standing hypothesis of mouthpart damage as a pathway for Bd-induced reductions in larval group. Here we provide evidence for reduced foraging efficiency (percentage of food ingested) as a mechanism for Bd-induced reductions in body size. This work highlights the importance of studying the sublethal effects of Bd on larval amphibians.
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Affiliation(s)
- Shane M Hanlon
- Department of Biological Sciences, University of Memphis, Memphis, TN 38152, USA
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32
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Hanlon SM, Lynch KJ, Parris MJ. Mouthparts of southern leopard frog, Lithobates sphenocephalus, tadpoles not affected by exposure to a formulation of glyphosate. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2013; 91:611-5. [PMID: 24068468 DOI: 10.1007/s00128-013-1117-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 09/19/2013] [Indexed: 06/02/2023]
Abstract
This study evaluated the impacts of Roundup® on tadpole mouthpart damage as a mechanism for reduced growth and developmental rates in Lithobates sphenocephalus (Southern leopard frog) tadpoles. We did not find evidence that Roundup(®) damages larval mouthparts, nor was there a significant relationship between mouthpart damage and either body condition or developmental rate. However, the highest concentration of Roundup® significantly stunted development compared to all other treatments. Although we observed a significant effect of Roundup® on developmental rate, we conclude that mouthpart damage is likely not a mechanism for this life history response.
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Affiliation(s)
- Shane M Hanlon
- Department of Biological Sciences, University of Memphis, Memphis, TN, 38152-353, USA,
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