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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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2
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Hopkins AP, Hoverman JT. Strobilurin fungicide increases the susceptibility of amphibian larvae to trematode infections. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2024; 269:106864. [PMID: 38422928 DOI: 10.1016/j.aquatox.2024.106864] [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: 10/25/2023] [Revised: 02/14/2024] [Accepted: 02/16/2024] [Indexed: 03/02/2024]
Abstract
The global rise in fungal pathogens has driven the increased usage of fungicides, yet our understanding of their ecotoxicity remains largely limited to acute toxicity. While such data is critical for projecting the risk of fungicide exposure to individual species, the contamination of natural systems with fungicides also has the potential to alter species interactions within communities including host-parasite relationships. We examined the effects of the fungicide pyraclostrobin on the susceptibility of larval American bullfrogs (Rana catesbeiana) to trematode (echinostome) infections using a controlled laboratory experiment. Following a 2-wk exposure to 0, 1.0, 5.2, or 8.4 µg/L of pyraclostrobin, tadpoles were then exposed to parasites either in the 1) presence (continued/simultaneous exposure) or 2) absence (fungicide-free water) of pyraclostrobin. We found that when exposed to pyraclostrobin during parasite exposure, meta cercariae counts increased 4 to 8 times compared to control tadpoles. Additionally, parasite loads were approximately 2 times higher in tadpoles with continued fungicide exposures compared to tadpoles that were moved to fresh water following fungicide exposure. This research demonstrates that fungicides at environmentally relevant concentrations can indirectly alter host-parasite interactions, which could elevate disease risk. It also underscores the need for studies that expand beyond traditional toxicity experiments to assess the potential community and ecosystem-level implications of environmental contaminants.
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Affiliation(s)
- Andrew P Hopkins
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN, United States.
| | - Jason T Hoverman
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN, United States
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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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Tytar V, Nekrasova O, Pupins M, Skute A, Kirjušina M, Gravele E, Mezaraupe L, Marushchak O, Čeirāns A, Kozynenko I, Kulikova AA. Modeling the Distribution of the Chytrid Fungus Batrachochytrium dendrobatidis with Special Reference to Ukraine. J Fungi (Basel) 2023; 9:607. [PMID: 37367543 DOI: 10.3390/jof9060607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/21/2023] [Accepted: 05/22/2023] [Indexed: 06/28/2023] Open
Abstract
Amphibians are the most threatened group of vertebrates. While habitat loss poses the greatest threat to amphibians, a spreading fungal disease caused by Batrachochytrium dendrobatidis Longcore, Pessier & D.K. Nichols 1999 (Bd) is seriously affecting an increasing number of species. Although Bd is widely prevalent, there are identifiable heterogeneities in the pathogen's distribution that are linked to environmental parameters. Our objective was to identify conditions that affect the geographic distribution of this pathogen using species distribution models (SDMs) with a special focus on Eastern Europe. SDMs can help identify hotspots for future outbreaks of Bd but perhaps more importantly identify locations that may be environmental refuges ("coldspots") from infection. In general, climate is considered a major factor driving amphibian disease dynamics, but temperature in particular has received increased attention. Here, 42 environmental raster layers containing data on climate, soil, and human impact were used. The mean annual temperature range (or 'continentality') was found to have the strongest constraint on the geographic distribution of this pathogen. The modeling allowed to distinguish presumable locations that may be environmental refuges from infection and set up a framework to guide future search (sampling) of chytridiomycosis in Eastern Europe.
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Affiliation(s)
- Volodymyr Tytar
- I.I. Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine, 01030 Kyiv, Ukraine
| | - Oksana Nekrasova
- I.I. Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine, 01030 Kyiv, Ukraine
- Department of Ecology, Institute of Life Sciences and Technologies, Daugavpils University, LV5400 Daugavpils, Latvia
| | - Mihails Pupins
- Department of Ecology, Institute of Life Sciences and Technologies, Daugavpils University, LV5400 Daugavpils, Latvia
| | - Arturs Skute
- Department of Ecology, Institute of Life Sciences and Technologies, Daugavpils University, LV5400 Daugavpils, Latvia
| | - Muza Kirjušina
- Department of Ecology, Institute of Life Sciences and Technologies, Daugavpils University, LV5400 Daugavpils, Latvia
| | - Evita Gravele
- Department of Ecology, Institute of Life Sciences and Technologies, Daugavpils University, LV5400 Daugavpils, Latvia
| | - Ligita Mezaraupe
- Department of Ecology, Institute of Life Sciences and Technologies, Daugavpils University, LV5400 Daugavpils, Latvia
| | - Oleksii Marushchak
- I.I. Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine, 01030 Kyiv, Ukraine
| | - Andris Čeirāns
- Department of Ecology, Institute of Life Sciences and Technologies, Daugavpils University, LV5400 Daugavpils, Latvia
| | - Iryna Kozynenko
- I.I. Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine, 01030 Kyiv, Ukraine
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Rollins-Smith LA. The importance of antimicrobial peptides (AMPs) in amphibian skin defense. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 142:104657. [PMID: 36754220 DOI: 10.1016/j.dci.2023.104657] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 01/20/2023] [Accepted: 02/04/2023] [Indexed: 06/18/2023]
Abstract
Antimicrobial peptides (AMPs) are produced for defense in nearly all taxa from simple bacteria to complex mammalian species. Some amphibian families have developed this defensive strategy to a high level of sophistication by loading the AMPs into specialized granular glands within the dermis. Enervated by the sympathetic nervous system, the granular glands are poised to deliver an array of AMPs to cleanse the wound and facilitate healing. There have been a number of excellent review publications in recent years that describe amphibian AMPs with an emphasis on their possible uses for human medicine. Instead, my aim here is to review what is known about the nature of amphibian AMPs, the diversity of amphibian AMPs, regulation of their production, and to provide the accumulated evidence that they do, indeed, play an important role in the protection of amphibian skin, vital for survival. While much has been learned about amphibian AMPs, there are still important gaps in our understanding of peptide synthesis, storage, and functions.
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Affiliation(s)
- Louise A Rollins-Smith
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
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6
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Wu NC. Pathogen load predicts host functional disruption: A meta‐analysis of an amphibian fungal panzootic. Funct Ecol 2023. [DOI: 10.1111/1365-2435.14245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Nicholas C. Wu
- Hawkesbury Institute for the Environment Western Sydney University Richmond New South Wales Australia
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7
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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: 6] [Impact Index Per Article: 3.0] [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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8
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Snyder MN, Henderson WM, Glinski DA, Purucker ST. Differentiating metabolomic responses of amphibians to multiple stressors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:155666. [PMID: 35598671 PMCID: PMC9875051 DOI: 10.1016/j.scitotenv.2022.155666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 04/26/2022] [Accepted: 04/29/2022] [Indexed: 06/15/2023]
Abstract
One of the biggest challenges in ecological risk assessment is determining the impact of multiple stressors on individual organisms and populations in real world scenarios. Frequently, data derived from laboratory studies of single stressors are used to estimate risk parameters and do not adequately address scenarios where other stressors exist. Emerging 'omic technologies, notably metabolomics, provide an opportunity to address the uncertainties surrounding ecological risk assessment of multiple stressors. The objective of this study was to use metabolomic profiling to investigate the effect of multiple stressors on amphibian metamorphs. We exposed post-metamorphosis (180 days) southern leopard frogs (Lithobates sphenocephala) to the insecticide carbaryl (480 μg/L), predation stress, and a combined pesticide and predation stress treatment. Corticosterone analysis revealed mild support for an induction in response to predation stress alone but strongly suggests that carbaryl exposure, alone or in combination with predation cues, can significantly elevate this known biomarker in amphibians. Metabolomics analysis accurately classed, based on relative nearness, carbaryl and predation induced changes in the hepatic metabolome and biochemical fluxes appear to be associated with a similar biological response. Support vector machine analysis with recursive feature elimination of the acquired metabolomic spectra demonstrated 85-96% classification accuracy among control and all treatment groups when using the top 75 ranked retention time bins. Biochemical fluxes observed in the groups exposed to carbaryl, predation, and the combined treatment include amino acids, sugar derivatives, and purine nucleotides. Ultimately, this methodology could be used to interpret short-term toxicity assays and the presence of environmental stressors to overall metabolomic effects in non-target organisms.
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Affiliation(s)
- Marcía N Snyder
- U.S. Environmental Protection Agency, ORD/CPHEA, Corvallis, OR 97333, USA.
| | | | - Donna A Glinski
- NRC Postdoctoral Research Fellow with the U.S. Environmental Protection Agency, Athens, GA 30605, USA.
| | - S Thomas Purucker
- U.S. Environmental Protection Agency, ORD/CCTE, Research Triangle Park, NC 27709, USA.
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Human impact modulates chytrid fungus occurrence in amphibians in the Brazilian Atlantic Forest. Perspect Ecol Conserv 2022. [DOI: 10.1016/j.pecon.2022.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Smalling KL, Mosher BA, Iwanowicz LR, Loftin KA, Boehlke A, Hladik ML, Muletz-Wolz CR, Córtes-Rodríguez N, Femmer R, Campbell Grant EH. Site- and Individual-Level Contaminations Affect Infection Prevalence of an Emerging Infectious Disease of Amphibians. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2022; 41:781-791. [PMID: 35040181 DOI: 10.1002/etc.5291] [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: 07/30/2021] [Revised: 11/29/2021] [Accepted: 01/09/2022] [Indexed: 06/14/2023]
Abstract
Emerging infectious disease outbreaks are one of multiple stressors responsible for amphibian declines globally. In the northeastern United States, ranaviral diseases are prevalent in amphibians and other ectothermic species, but there is still uncertainty as to whether their presence is leading to population-level effects. Further, there is also uncertainty surrounding the potential interactions among disease infection prevalence in free-ranging animals and habitat degradation (co-occurrence of chemical stressors). The present study was designed to provide field-based estimates of the relationship between amphibian disease and chemical stressors. We visited 40 wetlands across three protected areas, estimated the prevalence of ranavirus among populations of larval wood frogs and spotted salamanders, and assessed chemical and biological stressors in wetland habitats and larval amphibians using a suite of selected bioassays, screening tools, and chemical analyses. Ranavirus was detected on larval amphibians from each protected area with an estimated occupancy ranging from 0.27 to 0.55. Considerable variation in ranavirus occupancy was also observed within and among each protected area. Of the stressors evaluated, ranavirus prevalence was strongly and positively related to concentrations of metalloestrogens (metals with the potential to bind to estrogen receptors) and total metals in wetland sediments and weakly and negatively related to total pesticide concentrations in larval amphibians. These results can be used by land managers to refine habitat assessments to include such environmental factors with the potential to influence disease susceptibility. Environ Toxicol Chem 2022;41:781-791. © 2022 SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.
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Affiliation(s)
- Kelly L Smalling
- New Jersey Water Science Center, US Geological Survey, Lawrenceville, New Jersey, USA
| | - Brittany A Mosher
- Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, Vermont, USA
| | - Luke R Iwanowicz
- Eastern Ecological Science Center at Leetown, US Geological Survey, Kearneysville, West Virginia, USA
| | - Keith A Loftin
- Kansas Water Science Center, US Geological Survey, Lawrence, Kansas, USA
| | - Adam Boehlke
- Geology, Geochemistry and Geophysics Science Center, US Geological Survey, Denver, Colorado, USA
| | - Michelle L Hladik
- California Water Science Center, US Geological Survey, Sacramento, California, USA
| | - Carly R Muletz-Wolz
- Center for Conservation Genomics, Smithsonian National Zoo and Conservation Biology Institute, Washington, DC, USA
| | - Nandadevi Córtes-Rodríguez
- Center for Conservation Genomics, Smithsonian National Zoo and Conservation Biology Institute, Washington, DC, USA
- Department of Biological Sciences, Ithaca College, Ithaca, New York, USA
| | - Robin Femmer
- Kansas Water Science Center, US Geological Survey, Lawrence, Kansas, USA
| | - Evan H Campbell Grant
- Eastern Ecological Science Center, S.O. Conte Anadromous Fish Research Laboratory, US Geological Survey, Turner Falls, Massachusetts, USA
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Wetsch O, Strasburg M, McQuigg J, Boone MD. Is overwintering mortality driving enigmatic declines? Evaluating the impacts of trematodes and the amphibian chytrid fungus on an anuran from hatching through overwintering. PLoS One 2022; 17:e0262561. [PMID: 35030210 PMCID: PMC8759641 DOI: 10.1371/journal.pone.0262561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/30/2021] [Indexed: 11/23/2022] Open
Abstract
Emerging infectious diseases are increasing globally and are an additional challenge to species dealing with native parasites and pathogens. Therefore, understanding the combined effects of infectious agents on hosts is important for species’ conservation and population management. Amphibians are hosts to many parasites and pathogens, including endemic trematode flatworms (e.g., Echinostoma spp.) and the novel pathogenic amphibian chytrid fungus (Batrachochytrium dendrobatidis [Bd]). Our study examined how exposure to trematodes during larval development influenced the consequences of Bd pathogen exposure through critical life events. We found that prior exposure to trematode parasites negatively impacted metamorphosis but did not influence the effect of Bd infection on terrestrial growth and survival. Bd infection alone, however, resulted in significant mortality during overwintering—an annual occurrence for most temperate amphibians. The results of our study indicated overwintering mortality from Bd could provide an explanation for enigmatic declines and highlights the importance of examining the long-term consequences of novel parasite exposure.
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Affiliation(s)
- Olivia Wetsch
- Department of Biology, Miami University, Oxford, Ohio, United States of America
- * E-mail:
| | - Miranda Strasburg
- Department of Biology, Miami University, Oxford, Ohio, United States of America
| | - Jessica McQuigg
- Department of Biology, Miami University, Oxford, Ohio, United States of America
| | - Michelle D. Boone
- Department of Biology, Miami University, Oxford, Ohio, United States of America
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12
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Carrasco GH, de Souza MB, de Souza Santos LR. Effect of multiple stressors and population decline of frogs. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:59519-59527. [PMID: 34505245 DOI: 10.1007/s11356-021-16247-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 08/25/2021] [Indexed: 06/13/2023]
Abstract
The ongoing decline in anuran populations is linked primarily to the effects of stressor agents such as pathogens, pesticides, alterations of natural landscapes, and the introduction of exotic species. Most studies that have evaluated the effects of these stressors have focused on a single component, which is the opposite of the reality of most natural environments, where anuran populations tend to suffer the influence of multiple agents simultaneously. Studies of the effects of the interaction between these components are extremely important, given that one agent may potentialize (synergistic effect) or weaken another (antagonistic effect) or, in some cases, have a neutral effect. The present study is based on the scientometric analysis of three bibliographic databases (ISI Web of Science, Scopus, and PubMed), which identified 1376 papers that reported on the global decline of anuran populations, although only 172 of these studies focused on the interactive effects of environmental stressors. Synergistic effects were the most frequent type of interaction, followed by antagonistic effects, and a small number of studies that found no clear interaction between the stressors. Pathogens and pesticides were the classes of stressor studied most frequently, while climate-pathogen and pathogen-pesticide interactions were the combinations that featured in the largest number of studies. Overall, we would recommend a more systematic focus on the dynamics of the interactions among the stressors that impact anuran populations, in particular for the elaboration of conservation programs, given that these agents tend to have complex combined effects.
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Affiliation(s)
- Guilherme Henrique Carrasco
- Laboratório de Ecotoxicologia e Sistemática Animal - Instituto Federal Goiano - IF Goiano, Rodovia Sul Goiana, Km 01, Zona Rural, Rio Verde, GO, 75.901-970, Brazil.
| | - Marcelino Benvindo de Souza
- Laboratório de Mutagênese, Instituto de Ciências Biológicas, ICB I - Universidade Federal de Goiás, Campus Samambaia, Goiânia, GO, 74690-900, Brazil
| | - Lia Raquel de Souza Santos
- Laboratório de Ecotoxicologia e Sistemática Animal - Instituto Federal Goiano - IF Goiano, Rodovia Sul Goiana, Km 01, Zona Rural, Rio Verde, GO, 75.901-970, Brazil.
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Godwin CD, Walker DM, Romer AS, Grajal-Puche A, Grisnik M, Goessling JM, Perkin JS, Murray CM. Testing the febrile response of snakes inoculated with Ophidiomyces ophidiicola, the causative agent of snake fungal disease. J Therm Biol 2021; 100:103065. [PMID: 34503803 DOI: 10.1016/j.jtherbio.2021.103065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 07/09/2021] [Accepted: 08/01/2021] [Indexed: 11/28/2022]
Abstract
Snake Fungal Disease (SFD) negatively impacts wild snake populations in the eastern United States and Europe. Ophidiomyces ophidiicola causes SFD and manifests clinically by the formation of heterophilic granulomas around the mouth and eyes, weight loss, impaired vision, and sometimes death. Field observations have documented early seasonal basking behaviors in severely infected snakes, potentially suggesting induction of a behavioral febrile response to combat the mycosis. This study tested the hypothesis that snakes inoculated with Ophidiomyces ophidiicola would seek elevated basking temperatures to control body temperature and behaviorally induce a febrile response. Eastern ribbon snakes (Thamnophis saurita, n = 29) were experimentally or sham inoculated with O. ophidiicola. Seven days after inoculation, snakes were tested on a thermal gradient and the internal body temperature and substrate temperature of each snake was recorded over time. Quantitative PCR was used when snakes arrived, during pre-inoculation, and post-inoculation to test snakes for the presence of O. ophidiicola. Some snakes arrived with O. ophidiicola and were subsequently inoculated, allowing for an assessment of secondary exposure effects. Snake thermoregulatory behavior was compared between 1) O. ophidiicola inoculated vs. sham inoculated treatments, 2) infected vs. disease negative groups, and 3) disease naïve vs. pre-exposed immune response categories. Neither internal nor substrate temperatures differed among initially prescribed, and qPCR recovered disease states, although infected snakes tended to reach a preferred body temperature faster than disease negative snakes. Snakes experiencing their first exposure (disease naïve) sought higher substrate temperatures than snakes experiencing their second exposure (pre-exposed). Here, we recover no evidence for behaviorally induced fever in snakes with SFD but do elucidate a febrile immune response associated with secondary exposure.
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Affiliation(s)
- Cody Davis Godwin
- Tennessee Technological University, Department of Biology, 1 William L Jones Dr, Cookeville, TN, 38505, USA
| | - Donald M Walker
- Middle Tennessee State University, Department of Biology, 1301 E Main St, Murfreesboro, TN, 37132, USA.
| | - Alexander S Romer
- Middle Tennessee State University, Department of Biology, 1301 E Main St, Murfreesboro, TN, 37132, USA
| | - Alejandro Grajal-Puche
- Middle Tennessee State University, Department of Biology, 1301 E Main St, Murfreesboro, TN, 37132, USA; Northern Arizona University, Department of Biological Sciences, Flagstaff, AZ, 86011, USA
| | - Matthew Grisnik
- Middle Tennessee State University, Department of Biology, 1301 E Main St, Murfreesboro, TN, 37132, USA
| | | | - Joshua S Perkin
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Christopher M Murray
- Tennessee Technological University, Department of Biology, 1 William L Jones Dr, Cookeville, TN, 38505, USA; Southeastern Louisiana University, Department of Biological Sciences, Hammond, LA, 70402, USA
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14
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The Fungicide Chlorothalonil Changes the Amphibian Skin Microbiome: A Potential Factor Disrupting a Host Disease-Protective Trait. Appl Microbiol 2021. [DOI: 10.3390/applmicrobiol1010004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The skin microbiome is an important part of amphibian immune defenses and protects against pathogens such as the chytrid fungus Batrachochytrium dendrobatidis (Bd), which causes the skin disease chytridiomycosis. Alteration of the microbiome by anthropogenic factors, like pesticides, can impact this protective trait, disrupting its functionality. Chlorothalonil is a widely used fungicide that has been recognized as having an impact on amphibians, but so far, no studies have investigated its effects on amphibian microbial communities. In the present study, we used the amphibian Lithobates vibicarius from the montane forest of Costa Rica, which now appears to persist despite ongoing Bd-exposure, as an experimental model organism. We used 16S rRNA amplicon sequencing to investigate the effect of chlorothalonil on tadpoles’ skin microbiome. We found that exposure to chlorothalonil changes bacterial community composition, with more significant changes at a higher concentration. We also found that a larger number of bacteria were reduced on tadpoles’ skin when exposed to the higher concentration of chlorothalonil. We detected four presumed Bd-inhibitory bacteria being suppressed on tadpoles exposed to the fungicide. Our results suggest that exposure to a widely used fungicide could be impacting host-associated bacterial communities, potentially disrupting an amphibian protective trait against pathogens.
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15
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Amphibian Infection Risk Changes with Host Life Stage and across a Landscape Gradient. J HERPETOL 2020. [DOI: 10.1670/19-107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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16
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B. Assis A, R. Bevier C, Chaves Barreto C, Arturo Navas C. Environmental influences on and antimicrobial activity of the skin microbiota of Proceratophrys boiei (Amphibia, Anura) across forest fragments. Ecol Evol 2020; 10:901-913. [PMID: 32015853 PMCID: PMC6988551 DOI: 10.1002/ece3.5949] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 11/19/2019] [Accepted: 11/27/2019] [Indexed: 01/07/2023] Open
Abstract
The composition of the skin microbiota of amphibians is related to the biology of host species and environmental microbial communities. In this system, the environment serves as a microbial source and can modulate the hosted community. When habitats are fragmented and the environment disturbed, changes in the structure of this microbial community are expected. One important potential consequence of fragmentation is a compromised protective function of the microbiota against pathogenic microorganisms. In this study, the skin microbiota of the amphibian Proceratophrys boiei was characterized, evaluated for relationships with environmental variables and environmental sources of microbial communities, and its diversity evaluated for frog populations from fragmented and continuous forests. In addition, the antimicrobial activity of this skin community was studied in frogs from both forest types. Culture methods and 16S rRNA high-throughput gene sequencing were used to characterize the microbial community and demonstrated that the skin microbiota of P. boiei is more closely related to the soil microbial communities than those inhabiting water bodies or fragment matrix, the unforested area around the forested fragment. The microbial diversity and abundance of P. boiei skin microbiota are different between continuous forests and fragments. This community is correlated with environmental variables, especially with temperature of microhabitat and distance to human dwelling. All individuals of P. boiei harbored bacteria capable of inhibiting the growth of pathogenic bacteria and different strains of the pathogenic fungus Batrachochytrium dendrobatidis, and a total of 27 bacterial genera were detected. The results of this study indicate that the persistence of populations of this species will need balanced and sustained interactions among host, microorganisms, and environment.
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Affiliation(s)
- Ananda B. Assis
- Department of PhysiologyInstitute of BioscienceUniversity of São PauloSão PauloBrazil
| | | | - Cristine Chaves Barreto
- Graduate Program in Genomic Sciences and BiotechnologyCatholic University of BrasíliaBrasíliaBrazil
| | - Carlos Arturo Navas
- Department of PhysiologyInstitute of BioscienceUniversity of São PauloSão PauloBrazil
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17
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Campbell LJ, Pawlik AH, Harrison XA. Amphibian ranaviruses in Europe: important directions for future research. Facets (Ott) 2020. [DOI: 10.1139/facets-2020-0007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ranaviruses are an emerging group of pathogens capable of infecting all cold-blooded vertebrates. In Europe, ranaviruses pose a particularly potent threat to wild amphibian populations. Since the 1980s research on amphibian-infecting ranaviruses in Europe has been growing. The wide distribution of amphibian populations in Europe, the ease with which many are monitored, and the tractable nature of counterpart ex situ experimental systems have provided researchers with a unique opportunity to study many aspects of host–ranavirus interactions in the wild. These characteristics of European amphibian populations will also enable researchers to lead the way as the field of host–ranavirus interactions progresses. In this review, we provide a summary of the current key knowledge regarding amphibian infecting ranaviruses throughout Europe. We then outline important areas of further research and suggest practical ways each could be pursued. We address the study of potential interactions between the amphibian microbiome and ranaviruses, how pollution may exacerbate ranaviral disease either as direct stressors of amphibians or indirect modification of the amphibian microbiome. Finally, we discuss the need for continued surveillance of ranaviral emergence in the face of climate change.
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Affiliation(s)
- Lewis J. Campbell
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53711, USA
| | - Alice H. Pawlik
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall TR10 9FE, UK
| | - Xavier A. Harrison
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall TR10 9FE, UK
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18
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Varga JFA, Bui-Marinos MP, Katzenback BA. Frog Skin Innate Immune Defences: Sensing and Surviving Pathogens. Front Immunol 2019; 9:3128. [PMID: 30692997 PMCID: PMC6339944 DOI: 10.3389/fimmu.2018.03128] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 12/18/2018] [Indexed: 01/26/2023] Open
Abstract
Amphibian skin is a mucosal surface in direct and continuous contact with a microbially diverse and laden aquatic and/or terrestrial environment. As such, frog skin is an important innate immune organ and first line of defence against pathogens in the environment. Critical to the innate immune functions of frog skin are the maintenance of physical, chemical, cellular, and microbiological barriers and the complex network of interactions that occur across all the barriers. Despite the global decline in amphibian populations, largely as a result of emerging infectious diseases, we understand little regarding the cellular and molecular mechanisms that underlie the innate immune function of amphibian skin and defence against pathogens. In this review, we discuss the structure, cell composition and cellular junctions that contribute to the skin physical barrier, the antimicrobial peptide arsenal that, in part, comprises the chemical barrier, the pattern recognition receptors involved in recognizing pathogens and initiating innate immune responses in the skin, and the contribution of commensal microbes on the skin to pathogen defence. We briefly discuss the influence of environmental abiotic factors (natural and anthropogenic) and pathogens on the immunocompetency of frog skin defences. Although some aspects of frog innate immunity, such as antimicrobial peptides are well-studied; other components and how they contribute to the skin innate immune barrier, are lacking. Elucidating the complex network of interactions occurring at the interface of the frog's external and internal environments will yield insight into the crucial role amphibian skin plays in host defence and the environmental factors leading to compromised barrier integrity, disease, and host mortality.
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Affiliation(s)
- Joseph F A Varga
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
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19
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Campbell L, Bower DS, Clulow S, Stockwell M, Clulow J, Mahony M. Interaction between temperature and sublethal infection with the amphibian chytrid fungus impacts a susceptible frog species. Sci Rep 2019; 9:83. [PMID: 30643160 PMCID: PMC6331562 DOI: 10.1038/s41598-018-35874-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 11/07/2018] [Indexed: 11/09/2022] Open
Abstract
The amphibian chytrid fungus Batrachochytrium dendrobatidis is an emerging infectious pathogen present on every continent except Antarctica. It causes the disease chytridiomycosis in a subset of species but does not always result in disease or death for every host. Ambient temperature influences both amphibian metabolism and chytrid pathogenicity, however the interactive effects on host physiology is not well understood. We investigated the sublethal effect of B. dendrobatidis infection on a susceptible host, Litoria aurea to test (1) whether the infection load, metabolic activity, body fat and gonad size differed in L. aurea at either 24 °C or 12 °C ambient temperatures and (2) whether previous Bd infection caused long-term changes to body fat and gonad size. Litoria aurea in 12 °C treatments had higher infection loads of B. dendrobatidis and lower survivorship. Metabolic rate was higher and fat mass was lower in infected individuals and in animals in 24 °C treatments. Male L. aurea previously infected with B. dendrobatidis had smaller testes 5 months-post clearance of infection, an effect likely to translate to fitness costs in wild populations. These experiments demonstrate a physiological cost to sublethal B. dendrobatidis infection, which suggests a reduction in host fitness mediated by temperature in the host's environment regardless of whether infection leads to mortality.
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Affiliation(s)
- Lachlan Campbell
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Newcastle, 2300, NSW, Australia.
| | - Deborah S Bower
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Newcastle, 2300, NSW, Australia.,James Cook University, Townsville, 4811, Qld, Australia
| | - Simon Clulow
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Newcastle, 2300, NSW, Australia.,Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Michelle Stockwell
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Newcastle, 2300, NSW, Australia
| | - John Clulow
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Newcastle, 2300, NSW, Australia
| | - Michael Mahony
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Newcastle, 2300, NSW, Australia
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20
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Tennessen JB, Parks SE, Swierk L, Reinert LK, Holden WM, Rollins-Smith LA, Walsh KA, Langkilde T. Frogs adapt to physiologically costly anthropogenic noise. Proc Biol Sci 2018; 285:20182194. [PMID: 30464067 PMCID: PMC6253376 DOI: 10.1098/rspb.2018.2194] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 10/30/2018] [Indexed: 12/25/2022] Open
Abstract
Human activities impose novel pressures on amphibians, which are experiencing unprecedented global declines, yet population-level responses are poorly understood. A growing body of literature has revealed that noise is an anthropogenic stressor that impacts ecological processes spanning subcellular to ecosystem levels. These consequences can impose novel selective pressures on populations, yet whether populations can adapt to noise is unknown. We tested for adaptation to traffic noise, a widespread sensory 'pollutant'. We collected eggs of wood frogs (Rana sylvatica) from populations from different traffic noise regimes, reared hatchlings under the same conditions, and tested frogs for differences in sublethal fitness-relevant effects of noise. We show that prolonged noise impaired production of antimicrobial peptides associated with defence against disease. Additionally, noise and origin site interacted to impact immune and stress responses. Noise exposure altered leucocyte production and increased baseline levels of the stress-relevant glucocorticoid, corticosterone, in frogs from quiet sites, but noise-legacy populations were unaffected. These results suggest noise-legacy populations have adapted to avoid fitness-relevant physiological costs of traffic noise. These findings advance our understanding of the consequences of novel soundscapes and reveal a pathway by which anthropogenic disturbance can enable adaptation to novel environments.
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Affiliation(s)
- Jennifer B Tennessen
- Department of Biology, Center for Brain, Behavior and Cognition, The Pennsylvania State University, 208 Mueller Laboratory, University Park, PA 16802, USA
| | - Susan E Parks
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY 13244, USA
| | - Lindsey Swierk
- Department of Biology, Center for Brain, Behavior and Cognition, The Pennsylvania State University, 208 Mueller Laboratory, University Park, PA 16802, USA
- School of Forestry and Environmental Studies, Yale University, 370 Prospect Street, New Haven, CT 06511, USA
| | - Laura K Reinert
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, A-5301 Medical Center North, Nashville, TN 37232, USA
| | - Whitney M Holden
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, A-5301 Medical Center North, Nashville, TN 37232, USA
| | - Louise A Rollins-Smith
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, A-5301 Medical Center North, Nashville, TN 37232, USA
| | - Koranda A Walsh
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104, USA
| | - Tracy Langkilde
- Department of Biology, Center for Brain, Behavior and Cognition, The Pennsylvania State University, 208 Mueller Laboratory, University Park, PA 16802, USA
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21
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Rončević T, Gerdol M, Spazzali F, Florian F, Mekinić S, Tossi A, Pallavicini A. Parallel identification of novel antimicrobial peptide sequences from multiple anuran species by targeted DNA sequencing. BMC Genomics 2018; 19:827. [PMID: 30458708 PMCID: PMC6245896 DOI: 10.1186/s12864-018-5225-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 11/06/2018] [Indexed: 12/20/2022] Open
Abstract
Background Antimicrobial peptides (AMPs) are multifunctional effector molecules that often combine direct antimicrobial activities with signaling or immunomodulatory functions. The skin secretions of anurans contain a variety of such bioactive peptides. The identification of AMPs from frog species often requires sacrificing several specimens to obtain small quantities of crude peptides, followed by activity based fractionation to identify the active principles. Results We report an efficient alternative approach to selectively amplify AMP-coding transcripts from very small amounts of tissue samples, based on RNA extraction and cDNA synthesis, followed by PCR amplification and high-throughput sequencing of size-selected amplicons. This protocol exploits the highly conserved signal peptide region of the AMP precursors from Ranidae, Hylidae and Bombinatoridae for the design of family-specific, forward degenerate primers, coupled with a reverse primer targeting the mRNA poly-A tail. Conclusions Analysis of the assembled sequencing output allowed to identify more than a hundred full-length mature peptides, mostly from Ranidae species, including several novel potential AMPs for functional characterization. This (i) confirms the effectiveness of the experimental approach and indicates points for protocol optimization to account for particular cases, and (ii) encourages the application of the same methodology to other multigenic AMP families, also from other genera, sharing common features as in anuran AMPs. Electronic supplementary material The online version of this article (10.1186/s12864-018-5225-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tomislav Rončević
- Department of Physics, Faculty of Science, University of Split, 21000, Split, Croatia.
| | - Marco Gerdol
- Department of Life Sciences, University of Trieste, 34127, Trieste, Italy
| | - Francesca Spazzali
- Department of Life Sciences, University of Trieste, 34127, Trieste, Italy
| | - Fiorella Florian
- Department of Life Sciences, University of Trieste, 34127, Trieste, Italy
| | - Stjepan Mekinić
- Public Institution for the Management of Protected Areas in the County of Split and Dalmatia - "Sea and karst", 21000, Split, Croatia
| | - Alessandro Tossi
- Department of Life Sciences, University of Trieste, 34127, Trieste, Italy
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22
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Rumschlag SL, Boone MD. High juvenile mortality in amphibians during overwintering related to fungal pathogen exposure. DISEASES OF AQUATIC ORGANISMS 2018; 131:13-28. [PMID: 30324911 DOI: 10.3354/dao03277] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The result of pathogen exposures may depend upon trade-offs in energetic demands for immune responses against host growth and survival. Environmental conditions may influence these trade-offs by affecting host size, or trade-offs may change across seasons, altering impacts of pathogens. We exposed northern leopard frog Lithobates pipiens tadpoles to different larval environments (low leaf litter, high density of conspecifics, atrazine, caged fish, or controls) that influenced size at metamorphosis. Subsequently, we exposed metamorphs to Batrachochytrium dendrobatidis (Bd), a fungal pathogen, just after metamorphosis and/or prior to overwintering 12 wk later. Bd exposure dramatically reduced survival during overwintering, with the strongest effects when hosts were exposed at both time points. Larval environments resulted in differences in host size. Those exposed to caged fish were 2.5 times larger than the smallest (those exposed to high density of conspecifics), but larval environment did not influence Bd effects on growth and survival. The largest frogs exposed to caged fish had greater survival through overwintering, but in the absence of Bd. We built stage-structured models to evaluate if overwinter mortality from Bd is capable of having effects on host populations. Our models suggest that Bd exposure after metamorphosis or before overwintering can reduce population growth rates. Our study demonstrates that hosts suffer little effects of Bd exposures following metamorphosis and that small body size did not hamper growth and survival. Instead, we provide evidence that winter mortality from Bd exposure is capable of reducing population sizes, providing a plausible mechanism for amphibian declines in temperate regions.
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23
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Çakıcı Ö. Histopathological analysis of carbaryl-induced toxicity in the spleen of Levantine frog, Pelophylax bedriagae (Anura: Ranidae). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:24917-24922. [PMID: 29931639 DOI: 10.1007/s11356-018-2538-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 06/12/2018] [Indexed: 06/08/2023]
Abstract
This study describes the histopathological effects of carbaryl in the spleen of Levantine frog, Pelophylax bedriage. Due to its primary role in immune system, it is important to research the toxic effects of pesticides, which play an important role in environmental pollution, on spleen. To that end, adult frogs were exposed to carbaryl for 96 h. Experimental groups contained low dose, (0.05 mg/g), medium dose (0.1 mg/g) and high dose (0.2 mg/g). After following exposure to carbaryl, the frogs were euthanised and dissected. In low-dose group, there were no important changes in spleen tissue. In medium-dose group, prominence in haemorrhage just below the capsule and an increase in the melanomacrophage number were determined. In high-dose group, in addition to increases in the melanomacrophages, separations in capsule, haemorrhage below capsule and within splenic tissue, sinusoidal enlargement, congestion in dilated sinusoid, hypertrophic plasma cells and fibrosis were determined as important histological lesions in exposed frogs. This study clearly showed that carbaryl caused important histopathological damages in splenic tissue of Pelophylax bedriagae. In view of these findings, it can be said that this insecticide has the capacity to disrupt spleen' functions.
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Affiliation(s)
- Özlem Çakıcı
- Science Faculty, Biology Department, Zoology Section, Ege University, Bornova, Izmir, Turkey.
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24
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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: 35] [Impact Index Per Article: 5.8] [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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25
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McCartney-Melstad E, Gidiş M, Shaffer HB. Population genomic data reveal extreme geographic subdivision and novel conservation actions for the declining foothill yellow-legged frog. Heredity (Edinb) 2018; 121:112-125. [PMID: 29941996 PMCID: PMC6039490 DOI: 10.1038/s41437-018-0097-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/17/2018] [Accepted: 05/13/2018] [Indexed: 12/25/2022] Open
Abstract
Genomic data have the potential to inform high resolution landscape genetic and biological conservation studies that go far beyond recent mitochondrial and microsatellite analyses. We characterize the relationships of populations of the foothill yellow-legged frog, Rana boylii, a declining, "sentinel" species for stream ecosystems throughout its range in California and Oregon. We generated RADseq data and applied phylogenetic methods, hierarchical Bayesian clustering, PCA and population differentiation with admixture analyses to characterize spatial genetic structure across the species range. To facilitate direct comparison with previous analyses, we included many localities and individuals from our earlier work based on mitochondrial DNA. The results are striking, and emphasize the power of our landscape genomic approach. We recovered five extremely differentiated primary clades that indicate that R. boylii may be the most genetically differentiated anuran yet studied. Our results provide better resolution and more spatially consistent patterns than our earlier work, confirming the increased resolving power of genomic data compared to single-locus studies. Genomic structure is not equal across the species distribution. Approximately half the range of R. boylii consists of a single, relatively uniform population, while Sierra Nevada and coastal California clades are deeply, hierarchically substructured with biogeographic breaks observed in other codistributed taxa. Our results indicate that clades should serve as management units for R. boylii rather than previously suggested watershed boundaries, and that the near-extinct population from southwestern California is particularly diverged, exhibits the lowest genetic diversity, and is a critical conservation target for species recovery.
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Affiliation(s)
- Evan McCartney-Melstad
- Department of Ecology and Evolutionary Biology, La Kretz Center for California Conservation Science, and Institute of the Environment and Sustainability, University of California, Los Angeles, CA, USA.
| | - Müge Gidiş
- Department of Ecology and Evolutionary Biology, La Kretz Center for California Conservation Science, and Institute of the Environment and Sustainability, University of California, Los Angeles, CA, USA
- Kütahya School of Health, Dumlupınar University, Kütahya, Turkey
| | - H Bradley Shaffer
- Department of Ecology and Evolutionary Biology, La Kretz Center for California Conservation Science, and Institute of the Environment and Sustainability, University of California, Los Angeles, CA, USA
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26
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McCoy KA, Peralta AL. Pesticides Could Alter Amphibian Skin Microbiomes and the Effects of Batrachochytrium dendrobatidis. Front Microbiol 2018; 9:748. [PMID: 29731742 PMCID: PMC5919957 DOI: 10.3389/fmicb.2018.00748] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 04/03/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Krista A McCoy
- Department of Biology, East Carolina University, Greenville, NC, United States
| | - Ariane L Peralta
- Department of Biology, East Carolina University, Greenville, NC, United States
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27
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Yap TA, Koo MS, Ambrose RF, Vredenburg VT. Introduced bullfrog facilitates pathogen invasion in the western United States. PLoS One 2018; 13:e0188384. [PMID: 29659568 PMCID: PMC5901863 DOI: 10.1371/journal.pone.0188384] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 11/06/2017] [Indexed: 11/22/2022] Open
Abstract
Batrachochytrium dendrobatidis (Bd), a causal agent of the amphibian fungal skin disease chytridiomycosis, has been implicated in the decline and extinction of over 200 species worldwide since the 1970s. Despite almost two decades of research, the history of Bd and its global spread is not well understood. However, the spread of the Global Panzootic Lineage of Bd (Bd-GPL), the lineage associated with amphibian die-offs, has been linked with the American bullfrog (Rana [Aqurana] catesbeiana) and global trade. Interestingly, R. catesbeiana is native to the eastern U.S., where no Bd-related declines have been observed despite Bd’s presence since the late 1800s. In contrast Bd has been found to have emerged in California and Mexico in the 1960s and 1970s, after which epizootics (i.e., epidemics in wildlife) ensued. We hypothesize that Bd-GPL spread from the eastern U.S. with the introduction of R. catesbeiana into the western US, resulting in epizootics and declines of native host species. Using museum records, we investigated the historical relationship between R. catesbeiana and Bd invasion in the western US and found that R. catesbeiana arrived in the same year or prior to Bd in most western watersheds that had data for both species, suggesting that Bd-GPL may have originated in the eastern US and R. catesbeiana may have facilitated Bd invasion in the western US. To predict areas with greatest suitability for Bd, we created a suitability model by integrating habitat suitability and host availability. When we incorporated invasion history with high Bd suitability, we found that watersheds with non-native R. catesbeiana in the mountain ranges of the West Coast have the highest disease risk. These findings shed light on the invasion history and disease dynamics of Bd in North America. Targeted historical surveys using archived specimens in natural history collections and present-day field surveys along with more localized, community-level studies, monitoring, and surveillance are needed to further test this hypothesis and grow our understanding of the disease ecology and host-pathogen dynamics of Bd.
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Affiliation(s)
- Tiffany A. Yap
- Institute of the Environment and Sustainability, University of California, Los Angeles, California, United States of America
- Museum of Vertebrate Zoology, University of California, Berkeley, California, United States of America
- Department of Biology, San Francisco State University, San Francisco, California, United States of America
| | - Michelle S. Koo
- Museum of Vertebrate Zoology, University of California, Berkeley, California, United States of America
| | - Richard F. Ambrose
- Institute of the Environment and Sustainability, University of California, Los Angeles, California, United States of America
- Department of Environmental Health Sciences, University of California, Los Angeles, California, United States of America
| | - Vance T. Vredenburg
- Museum of Vertebrate Zoology, University of California, Berkeley, California, United States of America
- Department of Biology, San Francisco State University, San Francisco, California, United States of America
- * E-mail:
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28
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Zhelev Z, Tsonev S, Georgieva K, Arnaudova D. Health status of Pelophylax ridibundus (Amphibia: Ranidae) in a rice paddy ecosystem in Southern Bulgaria and its importance in assessing environmental state: haematological parameters. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:7884-7895. [PMID: 29297167 DOI: 10.1007/s11356-017-1109-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 12/19/2017] [Indexed: 05/24/2023]
Abstract
Pollution effects on haematological parameters in Pelophylax ridibundus individuals were investigated; animals were collected from two sites in Southern Bulgaria: the Tsalapitsa rice fields (RF) and the Vacha river (reference site, RS). Blood analysis showed significant differences between the haematological parameters of RBC, WBC, Hb, packed cell volume (PCV) and frogs' leucogram from RF and those from RS. These findings provide information on long-term background pollution of the habitat (RF) under investigation. In our view, the erythropenia, leucopenia, hypоchromia, lower values of PCV, St-neutrophilia, Sg-neutropenia, basopenia, eosinophilia, monocytosis and lymphopenia that were found in Pelophylax ridibundus individuals inhabiting the Tsalapitsa rice fields were probably caused by the pesticides and fertilizers that enter the paddy cages during the rice production process. The present study proves the practical usefulness of haematological parameters of Pelophylax ridibundus individuals in bioindication analyses for environmental assessment of agroecosystems.
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Affiliation(s)
- Zhivko Zhelev
- Faculty of Biology, Department of Human Anatomy and Physiology, Paisii Hilendarski University of Plovdiv, 24 Tzar Asen Str, 4000, Plovdiv, Bulgaria.
| | - Stefan Tsonev
- Abiotic Stress, AgroBioInstitute, 8 Dragan Tsankov, 1164, Sofia, Bulgaria
| | - Katerina Georgieva
- Department of Physiology, Medical University of Plovdiv, 15-A Vassil Aprilov Blvd, 4000, Plovdiv, Bulgaria
| | - Desislava Arnaudova
- Faculty of Biology, Department of Zoology, Paisii Hilendarski University of Plovdiv, 24 Tzar Asen Str, 4000, Plovdiv, Bulgaria
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29
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Ockleford C, Adriaanse P, Berny P, Brock T, Duquesne S, Grilli S, Hernandez-Jerez AF, Bennekou SH, Klein M, Kuhl T, Laskowski R, Machera K, Pelkonen O, Pieper S, Stemmer M, Sundh I, Teodorovic I, Tiktak A, Topping CJ, Wolterink G, Aldrich A, Berg C, Ortiz-Santaliestra M, Weir S, Streissl F, Smith RH. Scientific Opinion on the state of the science on pesticide risk assessment for amphibians and reptiles. EFSA J 2018; 16:e05125. [PMID: 32625798 PMCID: PMC7009658 DOI: 10.2903/j.efsa.2018.5125] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Following a request from EFSA, the Panel on Plant Protection Products and their Residues developed an opinion on the science to support the potential development of a risk assessment scheme of plant protection products for amphibians and reptiles. The coverage of the risk to amphibians and reptiles by current risk assessments for other vertebrate groups was investigated. Available test methods and exposure models were reviewed with regard to their applicability to amphibians and reptiles. Proposals were made for specific protection goals aiming to protect important ecosystem services and taking into consideration the regulatory framework and existing protection goals for other vertebrates. Uncertainties, knowledge gaps and research needs were highlighted.
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30
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Natale GS, Vera-Candioti J, Ruiz de Arcaute C, Soloneski S, Larramendy ML, Ronco AE. Lethal and sublethal effects of the pirimicarb-based formulation Aficida ® on Boana pulchella (Duméril and Bibron, 1841) tadpoles (Anura, Hylidae). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 147:471-479. [PMID: 28903092 DOI: 10.1016/j.ecoenv.2017.09.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 09/01/2017] [Accepted: 09/05/2017] [Indexed: 06/07/2023]
Abstract
Acute lethal and sublethal toxicity of the pirimicarb-based commercial formulation Aficida® were evaluated on Boana pulchella tadpoles. Whereas mortality was used as end point for lethality, frequency of micronuclei and other nuclear abnormalities as well as alterations in the frequency of erythroblasts in circulating blood as biomarkers for genotoxicity and cytotoxicity, respectively. Swimming, growth, developmental and morphological abnormalities were also employed as sublethal end points. Results show that the species is within the 13th percentile of the distribution of acute sensitivity of species to pirimicarb for aquatic vertebrates. Results revealed values of 23.78 and 101.45mg/L pirimicarb as LC5096h for GS25 and GS36 tadpoles, respectively. The most evident effects were related with the swimming activity with NOEC and LOEC values within the 0.005-0.39mg/L pirimicarb concentration range. Aficida® induced DNA damage at the chromosomal level by increasing micronuclei frequency and other nuclear abnormalities, i.e., lobbed and notched nuclei and binucleated cells. Cellular cytotoxicity was found after Aficida® treatment. The presence of abdominal oedemas in exposed organisms and thus flotation response of organisms could be proposed as a new sensitive exposure parameter. The multiple end point assessment approach used allowed a complete understanding the multi level of effects occurring by exposure to pirimicarb, at least in B. pulchella.
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Affiliation(s)
- G S Natale
- Centro de Investigaciones del Medio Ambiente (CIMA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - J Vera-Candioti
- Cátedra de Citología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Calle 64 N° 3, B1904AMA La Plata, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - C Ruiz de Arcaute
- Cátedra de Citología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Calle 64 N° 3, B1904AMA La Plata, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - S Soloneski
- Cátedra de Citología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Calle 64 N° 3, B1904AMA La Plata, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - M L Larramendy
- Cátedra de Citología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Calle 64 N° 3, B1904AMA La Plata, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
| | - A E Ronco
- Centro de Investigaciones del Medio Ambiente (CIMA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
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Cramp RL, Franklin CE. Exploring the link between ultraviolet B radiation and immune function in amphibians: implications for emerging infectious diseases. CONSERVATION PHYSIOLOGY 2018; 6:coy035. [PMID: 29992023 PMCID: PMC6022628 DOI: 10.1093/conphys/coy035] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/27/2018] [Accepted: 06/07/2018] [Indexed: 05/07/2023]
Abstract
Amphibian populations the world over are under threat of extinction, with as many as 40% of assessed species listed as threatened under IUCN Red List criteria (a significantly higher proportion than other vertebrate group). Amongst the key threats to amphibian species is the emergence of novel infectious diseases, which have been implicated in the catastrophic amphibian population declines and extinctions seen in many parts of the world. The recent emergence of these diseases coincides with increased ambient levels of ultraviolet B radiation (UVBR) due to anthropogenic thinning of the Earth's protective ozone layer, raising questions about potential interactions between UVBR exposure and disease in amphibians. While reasonably well documented in other vertebrate groups (particularly mammals), the immunosuppressive capacity of UVBR and the potential for it to influence disease outcomes has been largely overlooked in amphibians. Herein, we review the evidence for UVBR-associated immune system disruption in amphibians and identify a number of direct and indirect pathways through which UVBR may influence immune function and disease susceptibility in amphibians. By exploring the physiological mechanisms through which UVBR may affect host immune function, we demonstrate how ambient UVBR could increase amphibian susceptibility to disease. We conclude by discussing the potential implications of elevated UVBR for inter and intraspecific differences in disease dynamics and discuss how future research in this field may be directed to improve our understanding of the role that UVBR plays in amphibian immune function.
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Affiliation(s)
- Rebecca L Cramp
- School of Biological Sciences, The University of Queensland, Goddard Building (8), St Lucia, Queensland, Australia
- Corresponding author: School of Biological Sciences, The University of Queensland, Goddard Building (8), St Lucia, Queensland 4072, Australia.
| | - Craig E Franklin
- School of Biological Sciences, The University of Queensland, Goddard Building (8), St Lucia, Queensland, Australia
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Rohr JR, Brown J, Battaglin WA, McMahon TA, Relyea RA. A pesticide paradox: fungicides indirectly increase fungal infections. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2017; 27:2290-2302. [PMID: 28763165 PMCID: PMC5711531 DOI: 10.1002/eap.1607] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 04/21/2017] [Accepted: 07/11/2017] [Indexed: 05/17/2023]
Abstract
There are many examples where the use of chemicals have had profound unintended consequences, such as fertilizers reducing crop yields (paradox of enrichment) and insecticides increasing insect pests (by reducing natural biocontrol). Recently, the application of agrochemicals, such as agricultural disinfectants and fungicides, has been explored as an approach to curb the pathogenic fungus, Batrachochytrium dendrobatidis (Bd), which is associated with worldwide amphibian declines. However, the long-term, net effects of early-life exposure to these chemicals on amphibian disease risk have not been thoroughly investigated. Using a combination of laboratory experiments and analysis of data from the literature, we explored the effects of fungicide exposure on Bd infections in two frog species. Extremely low concentrations of the fungicides azoxystrobin, chlorothalonil, and mancozeb were directly toxic to Bd in culture. However, estimated environmental concentrations of the fungicides did not reduce Bd on Cuban tree frog (Osteopilus septentrionalis) tadpoles exposed simultaneously to any of these fungicides and Bd, and fungicide exposure actually increased Bd-induced mortality. Additionally, exposure to any of these fungicides as tadpoles resulted in higher Bd abundance and greater Bd-induced mortality when challenged with Bd post-metamorphosis, an average of 71 d after their last fungicide exposure. Analysis of data from the literature revealed that previous exposure to the fungicide itraconazole, which is commonly used to clear Bd infections, made the critically endangered booroolong frog (Litoria booroolongensis) more susceptible to Bd. Finally, a field survey revealed that Bd prevalence was positively associated with concentrations of fungicides in ponds. Although fungicides show promise for controlling Bd, these results suggest that, if fungicides do not completely eliminate Bd or if Bd recolonizes, exposure to fungicides has the potential to do more harm than good. To ensure that fungicide applications have the intended consequence of curbing amphibian declines, researchers must identify which fungicides do not compromise the pathogen resistance mechanisms of amphibians.
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Affiliation(s)
- Jason R. Rohr
- University of South Florida, Department of Integrative Biology, Tampa, FL 33620, USA
| | - Jenise Brown
- University of South Florida, Department of Integrative Biology, Tampa, FL 33620, USA
- SWCA Environmental Consultants, Pittsburgh, PA, 15017, USA
| | | | | | - Rick A. Relyea
- Department of Biological Sciences, Rensselaer Polytechnic Inst., Troy, NY 12180, USA
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Adams AJ, Pessier AP, Briggs CJ. Rapid extirpation of a North American frog coincides with an increase in fungal pathogen prevalence: Historical analysis and implications for reintroduction. Ecol Evol 2017; 7:10216-10232. [PMID: 29238549 PMCID: PMC5723621 DOI: 10.1002/ece3.3468] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 08/06/2017] [Accepted: 08/19/2017] [Indexed: 01/14/2023] Open
Abstract
As extinctions continue across the globe, conservation biologists are turning to species reintroduction programs as one optimistic tool for addressing the biodiversity crisis. For repatriation to become a viable strategy, fundamental prerequisites include determining the causes of declines and assessing whether the causes persist in the environment. Invasive species-especially pathogens-are an increasingly significant factor contributing to biodiversity loss. We hypothesized that Batrachochytrium dendrobatidis (Bd), the causative agent of the deadly amphibian disease chytridiomycosis, was important in the rapid (<10 years) localized extirpation of a North American frog (Rana boylii) and that Bd remains widespread among extant amphibians in the region of extirpation. We used an interdisciplinary approach, combining interviews with herpetological experts, analysis of archived field notes and museum specimen collections, and field sampling of the extant amphibian assemblage to examine (1) historical relative abundance of R. boylii; (2) potential causes of R. boylii declines; and (3) historical and contemporary prevalence of Bd. We found that R. boylii were relatively abundant prior to their rapid extirpation, and an increase in Bd prevalence coincided with R. boylii declines during a time of rapid change in the region, wherein backcountry recreation, urban development, and the amphibian pet trade were all on the rise. In addition, extreme flooding during the winter of 1969 coincided with localized extirpations in R. boylii populations observed by interview respondents. We conclude that Bd likely played an important role in the rapid extirpation of R. boylii from southern California and that multiple natural and anthropogenic factors may have worked in concert to make this possible in a relatively short period of time. This study emphasizes the importance of recognizing historical ecological contexts in making future management and reintroduction decisions.
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Affiliation(s)
- Andrea J Adams
- Department of Ecology, Evolution and Marine Biology University of California, Santa Barbara Santa Barbara CA USA
| | - Allan P Pessier
- Department of Veterinary Microbiology and Pathology College of Veterinary Medicine Washington State University Pullman WA USA
| | - Cheryl J Briggs
- Department of Ecology, Evolution and Marine Biology University of California, Santa Barbara Santa Barbara CA USA
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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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Bókony V, Mikó Z, Móricz ÁM, Krüzselyi D, Hettyey A. Chronic exposure to a glyphosate-based herbicide makes toad larvae more toxic. Proc Biol Sci 2017; 284:20170493. [PMID: 28679726 PMCID: PMC5524492 DOI: 10.1098/rspb.2017.0493] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 06/01/2017] [Indexed: 01/18/2023] Open
Abstract
Chemical pollutants can exert various sublethal effects on wildlife, leading to complex fitness consequences. Many animals use defensive chemicals as protection from predators and diseases, yet the effects of chemical contaminants on this important fitness component are poorly known. Understanding such effects is especially relevant for amphibians, the globally most threatened group of vertebrates, because they are particularly vulnerable to chemical pollution. We conducted two experiments to investigate how exposure to glyphosate-based herbicides, the most widespread agrochemicals worldwide, affects the production of bufadienolides, the main compounds of chemical defence in common toads (Bufo bufo). In both experiments, herbicide exposure increased the amount of bufadienolides in toad tadpoles. In the laboratory, individuals exposed to 4 mg a.e./L glyphosate throughout their larval development had higher bufadienolide content at metamorphosis than non-exposed tadpoles, whereas exposure for 9 days to the same concentration or to 2 mg a.e./L throughout larval development or for 9 days had no detectable effect. In outdoor mesocosms, tadpoles from 16 populations exhibited elevated bufadienolide content after three-weeks exposure to both concentrations of the herbicide. These results show that pesticide exposure can have unexpected effects on non-target organisms, with potential consequences for the conservation management of toxin-producing species and their predators.
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Affiliation(s)
- Veronika Bókony
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest 1022, Hungary
| | - 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
| | - Ágnes M Móricz
- Department of Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest 1022, Hungary
| | - Dániel Krüzselyi
- Department of Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest 1022, 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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Adams AJ, Kupferberg SJ, Wilber MQ, Pessier AP, Grefsrud M, Bobzien S, Vredenburg VT, Briggs CJ. Extreme drought, host density, sex, and bullfrogs influence fungal pathogen infection in a declining lotic amphibian. Ecosphere 2017. [DOI: 10.1002/ecs2.1740] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Andrea J. Adams
- Department of Ecology, Evolution, and Marine Biology; University of California; Santa Barbara California 93106 USA
| | - Sarah J. Kupferberg
- Department of Integrative Biology; University of California; Berkeley California 94720 USA
| | - Mark Q. Wilber
- Department of Ecology, Evolution, and Marine Biology; University of California; Santa Barbara California 93106 USA
| | - Allan P. Pessier
- Department of Veterinary Microbiology and Pathology; College of Veterinary Medicine; Washington State University; Pullman Washington 99164 USA
| | - Marcia Grefsrud
- California Department of Fish and Wildlife; Bay Delta Region Napa California 94558 USA
| | - Steve Bobzien
- East Bay Regional Park District; Oakland California 94605 USA
| | | | - Cheryl J. Briggs
- Department of Ecology, Evolution, and Marine Biology; University of California; Santa Barbara California 93106 USA
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De Jesús Andino F, Lawrence BP, Robert J. Long term effects of carbaryl exposure on antiviral immune responses in Xenopus laevis. CHEMOSPHERE 2017; 170:169-175. [PMID: 27988452 PMCID: PMC5205582 DOI: 10.1016/j.chemosphere.2016.12.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 12/04/2016] [Accepted: 12/05/2016] [Indexed: 05/06/2023]
Abstract
Water pollutants associated with agriculture may contribute to the increased prevalence of infectious diseases caused by ranaviruses. We have established the amphibian Xenopus laevis and the ranavirus Frog Virus 3 (FV3) as a reliable experimental platform for evaluating the effects of common waterborne pollutants, such as the insecticide carbaryl. Following 3 weeks of exposure to 10 ppb carbaryl, X. laevis tadpoles exhibited a marked increase in mortality and accelerated development. Exposure at lower concentrations (0.1 and 1.0 ppb) was not toxic, but it impaired tadpole innate antiviral immune responses, as evidenced by significantly decreased TNF-α, IL-1β, IFN-I, and IFN-III gene expression. The defect in IFN-I and IL-1β gene expression levels persisted after metamorphosis in froglets, whereas only IFN-I gene expression in response to FV3 was attenuated when carbaryl exposure was performed at the adult stage. These findings suggest that the agriculture-associated carbaryl exposure at low but ecologically-relevant concentrations has the potential to induce long term alterations in host-pathogen interactions and antiviral immunity.
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Affiliation(s)
| | - B Paige Lawrence
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, USA; Department of Environmental Medicine, University of Rochester Medical Center, Rochester, USA
| | - Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, USA; Department of Environmental Medicine, University of Rochester Medical Center, Rochester, USA.
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Stiles RM, Swan JW, Klemish JL, Lannoo MJ. Amphibian habitat creation on postindustrial landscapes: a case study in a reclaimed coal strip-mine area. CAN J ZOOL 2017. [DOI: 10.1139/cjz-2015-0163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although habitat loss is a major driver of amphibian and reptile declines globally, a subset of postindustrial landscapes, reclaimed and restored, are creating habitat for these animals in the United States. In southwestern Indiana, along the southeastern edge of the Illinois Coal Basin, post-SMCRA (Surface Mining Control and Reclamation Act of 1977) grassland restorations are recreating prairies in a region where they occurred naturally as openings (pockets) in deciduous forest, but were destroyed by agricultural activities following Euro-American settlement. Furthermore, it is likely, given the speed of recolonization by 34 species of amphibians and reptiles (9 frog, 5 salamander, 13 snake, 5 turtle, and 2 lizard species), that the grasslands associated with railroad spur-line right-of-ways act as corridors to facilitate movement of these species into these relatively large sites. We suggest that reclaimed, restored, and properly managed landscapes can support reproducing populations of amphibians and reptiles, including species in decline across other portions of their range.
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Affiliation(s)
- Rochelle M. Stiles
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA
| | - Jonathan W. Swan
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA
| | - Jaimie L. Klemish
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA
| | - Michael J. Lannoo
- Indiana University School of Medicine–TH, Terre Haute, IN 47809, 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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Terrestrial Growth in Northern Leopard Frogs Reared in the Presence or Absence of Predators and Exposed to the Amphibian Chytrid Fungus at Metamorphosis. J HERPETOL 2016. [DOI: 10.1670/15-102] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Zhang X, Cheng Y, Yang Y, Liu S, Shi H, Lu C, Li S, Nie L, Su D, Deng X, Ding K, Hao L. Polypeptides from the Skin of Rana chensinensis Exert the Antioxidant and Antiapoptotic Activities on HaCaT Cells. Anim Biotechnol 2016; 28:1-10. [DOI: 10.1080/10495398.2016.1188825] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Xin Zhang
- College of Animal Science, Jilin University, Changchun, Jilin Province, China
| | - Yunyun Cheng
- College of Animal Science, Jilin University, Changchun, Jilin Province, China
| | - Yang Yang
- Institute of Translational Medicine, The First Hospital, Jilin University, Changchun, Jilin Province, China
| | - Songcai Liu
- College of Animal Science, Jilin University, Changchun, Jilin Province, China
| | - Hui Shi
- College of Animal Science, Jilin University, Changchun, Jilin Province, China
| | - Chao Lu
- College of Animal Science, Jilin University, Changchun, Jilin Province, China
| | - Siming Li
- College of Animal Science, Jilin University, Changchun, Jilin Province, China
| | - Linyan Nie
- College of Animal Science, Jilin University, Changchun, Jilin Province, China
| | - Dan Su
- College of Animal Science, Jilin University, Changchun, Jilin Province, China
| | - Xuming Deng
- College of Animal Science, Jilin University, Changchun, Jilin Province, China
| | - Kexiang Ding
- Department of Radiation Medicine, School of Public Health and Tropic Medicine, Southern Medical University, Guangzhou, Guangzhou Province, China
| | - Linlin Hao
- College of Animal Science, Jilin University, Changchun, Jilin Province, China
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Çakıcı Ö. Histopathological study of toxic effects of carbaryl on digestive tract of Bufotes variabilis (Anura: Bufonidae). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:13432-13437. [PMID: 27026545 DOI: 10.1007/s11356-016-6529-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 03/21/2016] [Indexed: 06/05/2023]
Abstract
Due to the negative effects of pesticide usage in environment, i.e., decline in amphibian populations, this study was designed to examine histopathologic changes following carbaryl exposure for 96 h in the digestive tract of variable toad, Bufotes variabilis. After exposure to single doses of carbaryl (low dose 50 μg/g, medium dose 100 μg/g, and high dose: 200 μg/g), the toads were euthanized and dissected and digestive tract samples were quickly removed. Histopathology revealed esophageal vacuolization and necrosis in esophageal cells. Hemorrhage was also observed in the esophagus. In the stomach, necrosis in the glandular epithelium, congested blood vessels, edema among gastric glands, dilated tips of the mucosal epithelial layer, gastric glandular atrophy, and hemorrhage were found. In the intestine, edema within villi, hemorrhage, inflammation, vacuolization, and necrosis in epithelial cells of villi were detected. This study clearly showed that carbaryl caused adverse effects on the digestive tract of B. variabilis in all dose groups.
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Affiliation(s)
- Özlem Çakıcı
- Science Faculty, Biology Department, Zoology Section, Ege University, 35100, Bornova, İzmir, Turkey.
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Alto BW, Lord CC. Transstadial Effects of Bti on Traits of Aedes aegypti and Infection with Dengue Virus. PLoS Negl Trop Dis 2016; 10:e0004370. [PMID: 26871951 PMCID: PMC4752348 DOI: 10.1371/journal.pntd.0004370] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 12/17/2015] [Indexed: 12/03/2022] Open
Abstract
Most mosquito control efforts are primarily focused on reducing the adult population size mediated by reductions in the larval population, which should lower risk of disease transmission. Although the aim of larviciding is to reduce larval abundance and thus recruitment of adults, nonlethal effects on adults are possible, including transstadial effects on phenotypes of adults such as survival and pathogen infection and transmission. In addition, the mortality induced by control efforts may act in conjunction with other sources of mosquito mortality in nature. The consequences of these effects and interactions may alter the potential of the population to transmit pathogens. We tested experimentally the combined effects of a larvicide (Bacillus thuringiensis ssp. israelensis, Bti) and competition during the larval stages on subsequent Aedes aegypti (Linnaeus) traits, population performance, and susceptibility to dengue-1 virus infection. Ae. aegypti that survived exposure to Bti experienced accelerated development, were larger, and produced more eggs with increasing amounts of Bti, consistent with competitive release among surviving mosquitoes. Changing larval density had no significant interactive effect with Bti treatment on development and growth to adulthood. Larval density, but not Bti or treatment interaction, had a strong effect on survival of adult Ae. aegypti females. There were sharper declines in cumulative daily survival of adults from crowded than uncrowded larval conditions, suggesting that high competition conditions of larvae may be an impediment to transmission of dengue viruses. Rates of infection and dengue-1 virus disseminated infections were found to be 87±13% and 88±12%, respectively. There were no significant treatment effects on infection measurements. Our findings suggest that larvicide campaigns using Bti may reduce the number of emerged adults, but survivors will have a fitness advantage (growth, development, enhanced production of eggs) relative to conspecifics that are not under larvicide pressure. However, under most circumstances, these transstadial effects are unlikely to outweigh reductions in the adult population by Bti and altered risk of disease transmission.
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Affiliation(s)
- Barry W. Alto
- University of Florida, IFAS, Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Vero Beach, Florida, United States of America
| | - Cynthia C. Lord
- University of Florida, IFAS, Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Vero Beach, Florida, United States of America
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Stockwell MP, Bower DS, Clulow J, Mahony MJ. The role of non-declining amphibian species as alternative hosts for Batrachochytrium dendrobatidis in an amphibian community. WILDLIFE RESEARCH 2016. [DOI: 10.1071/wr15223] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context Pathogens with reservoir hosts have been responsible for most disease-induced wildlife extinctions because the decline of susceptible hosts does not cause the decline of the pathogen. The existence of reservoirs for Batrachochytrium dendrobatidis limits population recovery and conservation actions for threatened amphibians. As such, the effect of reservoirs on disease risk within host community assemblages needs to be considered, but rarely is. Aims In this study we aimed to determine if amphibian species co-occurring with the green and golden bell frog Litoria aurea, a declining species susceptible to B. dendrobatidis, act as alternate hosts. Methods We quantified B. dendrobatidis infection levels, sub-lethal effects on body condition and terminal signs of disease in amphibian communities on Kooragang Island and Sydney Olympic Park in New South Wales, Australia, where two of the largest remaining L. aurea populations persist. Key results We found L. aurea carried infections at a similar prevalence (6–38%) to alternate species. Infection loads ranged widely (0.01–11 107.3 zoospore equivalents) and L. aurea differed from only one alternate host species (higher median load in Litoria fallax) at one site. There were no terminal or sub-lethal signs of disease in any species co-occurring with L. aurea. Conclusion Our results suggest that co-occurring species are acting as alternate hosts to L. aurea and whether their presence dilutes or amplifies B. dendrobatidis in the community is a priority for future research. Implications For L. aurea and many other susceptible species, confirming the existence of reservoir hosts and understanding their role in community disease dynamics will be important for optimising the outcomes of threat mitigation and habitat creation initiatives for their long-term conservation.
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Vincent K, Davidson C. The toxicity of glyphosate alone and glyphosate-surfactant mixtures to western toad (Anaxyrus boreas) tadpoles. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2015; 34:2791-5. [PMID: 26084619 DOI: 10.1002/etc.3118] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 04/13/2015] [Accepted: 06/11/2015] [Indexed: 05/24/2023]
Abstract
Pesticide choice based on toxicity to nontarget wildlife is reliant on available toxicity data. Despite a number of recent studies examining the effects of glyphosate on amphibians, very few have aimed to understand the toxicological effects of glyphosate in combination with surfactants as it is commonly applied in the field. Land managers interested in making pesticide choices based on minimizing impacts to nontarget wildlife are hindered by a lack of published toxicity data. Short-term acute toxicity trials were conducted for glyphosate in the form of isopropylamine salt (IPA) alone and mixed with 2 surfactants: Agri-dex and Competitor with western toad (Anaxyrus [Bufo] boreas) tadpoles. Glyphosate IPA mixed with Competitor was 6 times more toxic than glyphosate IPA mixed with Agri-dex, and both mixtures were more toxic than glyphosate IPA alone. The median lethal concentrations reported for 24-h and 48-h exposures were 8279 mg/L (24 h) and 6392 mg/L (48 h) for glyphosate IPA alone; 5092 mg/L (24 h) and 4254 mg/L (48 h) for glyphosate IPA mixed with Agri-dex; and 853 mg/L (24 h) and 711 mg/L (48 h) for glyphosate IPA mixed with Competitor. The present study indicates that the toxicity of a tank mix may be greatly increased by the addition of surfactants and may vary widely depending on the specific surfactant.
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Affiliation(s)
- Kim Vincent
- Department of Biology, San Francisco State University, San Francisco, California, USA
| | - Carlos Davidson
- Environmental Studies Program, San Francisco State University, San Francisco, California, USA
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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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Rumschlag SL, Boone MD. How Time of Exposure to the Amphibian Chytrid Fungus AffectsHyla chrysoscelisin the Presence of an Insecticide1. HERPETOLOGICA 2015. [DOI: 10.1655/herpetologica-d-13-00070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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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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Krynak KL, Burke DJ, Benard MF. Larval Environment Alters Amphibian Immune Defenses Differentially across Life Stages and Populations. PLoS One 2015; 10:e0130383. [PMID: 26107644 PMCID: PMC4479591 DOI: 10.1371/journal.pone.0130383] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 05/20/2015] [Indexed: 02/02/2023] Open
Abstract
Recent global declines, extirpations and extinctions of wildlife caused by newly emergent diseases highlight the need to improve our knowledge of common environmental factors that affect the strength of immune defense traits. To achieve this goal, we examined the influence of acidification and shading of the larval environment on amphibian skin-associated innate immune defense traits, pre and post-metamorphosis, across two populations of American Bullfrogs (Rana catesbeiana), a species known for its wide-ranging environmental tolerance and introduced global distribution. We assessed treatment effects on 1) skin-associated microbial communities and 2) post-metamorphic antimicrobial peptide (AMP) production and 3) AMP bioactivity against the fungal pathogen Batrachochytrium dendrobatidis (Bd). While habitat acidification did not affect survival, time to metamorphosis or juvenile mass, we found that a change in average pH from 7 to 6 caused a significant shift in the larval skin microbial community, an effect which disappeared after metamorphosis. Additionally, we found shifts in skin-associated microbial communities across life stages suggesting they are affected by the physiological or ecological changes associated with amphibian metamorphosis. Moreover, we found that post-metamorphic AMP production and bioactivity were significantly affected by the interactions between pH and shade treatments and interactive effects differed across populations. In contrast, there were no significant interactions between treatments on post-metamorphic microbial community structure suggesting that variation in AMPs did not affect microbial community structure within our study. Our findings indicate that commonly encountered variation in the larval environment (i.e. pond pH and degree of shading) can have both immediate and long-term effects on the amphibian innate immune defense traits. Our work suggests that the susceptibility of amphibians to emerging diseases could be related to variability in the larval environment and calls for research into the relative influence of potentially less benign anthropogenic environmental changes on innate immune defense traits.
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Affiliation(s)
- Katherine L. Krynak
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - David J. Burke
- Research Department, The Holden Arboretum, Kirtland, Ohio, United States of America
| | - Michael F. Benard
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
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