1
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McGrath-Blaser SE, McGathey N, Pardon A, Hartmann AM, Longo AV. Invasibility of a North American soil ecosystem to amphibian-killing fungal pathogens. Proc Biol Sci 2024; 291:20232658. [PMID: 38628130 PMCID: PMC11021929 DOI: 10.1098/rspb.2023.2658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 03/19/2024] [Indexed: 04/19/2024] Open
Abstract
North American salamanders are threatened by intercontinental spread of chytridiomycosis, a deadly disease caused by the fungal pathogen Batrachochytrium salamandrivorans (Bsal). To predict potential dispersal of Bsal spores to salamander habitats, we evaluated the capacity of soil microbial communities to resist invasion. We determined the degree of habitat invasibility using soils from five locations throughout the Great Smoky Mountains National Park, a region with a high abundance of susceptible hosts. Our experimental design consisted of replicate soil microcosms exposed to different propagule pressures of the non-native pathogen, Bsal, and an introduced but endemic pathogen, B. dendrobatidis (Bd). To compare growth and competitive interactions, we used quantitative PCR, live/dead cell viability assays, and full-length 16S rRNA sequencing. We found that soil microcosms with intact bacterial communities inhibited both Bsal and Bd growth, but inhibitory capacity diminished with increased propagule pressure. Bsal showed greater persistence than Bd. Linear discriminant analysis (LDA) identified the family Burkolderiaceae as increasing in relative abundance with the decline of both pathogens. Although our findings provide evidence of environmental filtering in soils, such barriers weakened in response to pathogen type and propagule pressure, showing that habitats vary their invasibility based on properties of their local microbial communities.
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Affiliation(s)
| | - Natalie McGathey
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Allison Pardon
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Arik M. Hartmann
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Ana V. Longo
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
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2
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Osborne OG, Jiménez RR, Byrne AQ, Gratwicke B, Ellison A, Muletz-Wolz CR. Phylosymbiosis shapes skin bacterial communities and pathogen-protective function in Appalachian salamanders. THE ISME JOURNAL 2024; 18:wrae104. [PMID: 38861457 PMCID: PMC11195472 DOI: 10.1093/ismejo/wrae104] [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: 01/11/2024] [Revised: 05/09/2024] [Accepted: 06/10/2024] [Indexed: 06/13/2024]
Abstract
Phylosymbiosis is an association between host-associated microbiome composition and host phylogeny. This pattern can arise via the evolution of host traits, habitat preferences, diets, and the co-diversification of hosts and microbes. Understanding the drivers of phylosymbiosis is vital for modelling disease-microbiome interactions and manipulating microbiomes in multi-host systems. This study quantifies phylosymbiosis in Appalachian salamander skin in the context of infection by the fungal pathogen Batrachochytrium dendrobatidis (Bd), while accounting for environmental microbiome exposure. We sampled ten salamander species representing >150M years of divergence, assessed their Bd infection status, and analysed their skin and environmental microbiomes. Our results reveal a significant signal of phylosymbiosis, whereas the local environmental pool of microbes, climate, geography, and Bd infection load had a smaller impact. Host-microbe co-speciation was not evident, indicating that the effect stems from the evolution of host traits influencing microbiome assembly. Bd infection is correlated with host phylogeny and the abundance of Bd-inhibitory bacterial strains, suggesting that the long-term evolutionary dynamics between salamander hosts and their skin microbiomes affect the present-day distribution of the pathogen, along with habitat-linked exposure risk. Five Bd-inhibitory bacterial strains showed unusual generalism: occurring in most host species and habitats. These generalist strains may enhance the likelihood of probiotic manipulations colonising and persisting on hosts. Our results underscore the substantial influence of host-microbiome eco-evolutionary dynamics on environmental health and disease outcomes.
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Affiliation(s)
- Owen G Osborne
- School of Environmental and Natural Sciences, Bangor University, Deiniol Road, Bangor, Gwynedd LL57 2DG, United Kingdom
| | - Randall R Jiménez
- Center for Conservation Genomics, Smithsonian’s National Zoological Park and Conservation Biology Institute, Washington, DC 20008, United States
- International Union for Conservation of Nature, C. 39, Los Yoses, San Jose, 146-2150, Costa Rica
| | - Allison Q Byrne
- Center for Conservation Genomics, Smithsonian’s National Zoological Park and Conservation Biology Institute, Washington, DC 20008, United States
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720-3114, United States
| | - Brian Gratwicke
- Center for Species Survival, Smithsonian’s National Zoological Park and Conservation Biology Institute, Front Royal, VA 22630, United States
| | - Amy Ellison
- School of Environmental and Natural Sciences, Bangor University, Deiniol Road, Bangor, Gwynedd LL57 2DG, United Kingdom
| | - Carly R Muletz-Wolz
- Center for Conservation Genomics, Smithsonian’s National Zoological Park and Conservation Biology Institute, Washington, DC 20008, United States
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3
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Martínez-Ugalde E, Ávila-Akerberg V, González Martínez TM, Rebollar EA. Gene functions of the Ambystoma altamirani skin microbiome vary across space and time but potential antifungal genes are widespread and prevalent. Microb Genom 2024; 10:001181. [PMID: 38240649 PMCID: PMC10868611 DOI: 10.1099/mgen.0.001181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 01/02/2024] [Indexed: 01/23/2024] Open
Abstract
Amphibian skin microbiomes can play a critical role in host survival against emerging diseases by protecting their host against pathogens. While a plethora of biotic and abiotic factors have been shown to influence the taxonomic diversity of amphibian skin microbiomes it remains unclear whether functional genomic diversity varies in response to temporal and environmental factors. Here we applied a metagenomic approach to evaluate whether seasonality, distinct elevations/sites, and pathogen presence influenced the functional genomic diversity of the A. altamirani skin microbiome. We obtained a gene catalogue of 92 107 nonredundant annotated genes and a set of 50 unique metagenome assembled genomes (MAGs). Our analysis showed that genes linked to general and potential antifungal traits significantly differed across seasons and sampling locations at different elevations. Moreover, we found that the functional genomic diversity of A. altamirani skin microbiome differed between B. dendrobatidis infected and not infected axolotls only during winter, suggesting an interaction between seasonality and pathogen infection. In addition, we identified the presence of genes and biosynthetic gene clusters (BGCs) linked to potential antifungal functions such as biofilm formation, quorum sensing, secretion systems, secondary metabolite biosynthesis, and chitin degradation. Interestingly genes linked to these potential antifungal traits were mainly identified in Burkholderiales and Chitinophagales MAGs. Overall, our results identified functional traits linked to potential antifungal functions in the A. altamirani skin microbiome regardless of variation in the functional diversity across seasons, elevations/sites, and pathogen presence. Our findings suggest that potential antifungal traits found in Burkholderiales and Chitinophagales taxa could be related to the capacity of A. altamirani to survive in the presence of Bd, although further experimental analyses are required to test this hypothesis.
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Affiliation(s)
| | - Víctor Ávila-Akerberg
- Instituto de Ciencias Agropecuarias y Rurales, Universidad Autónoma del Estado de México, Toluca, Mexico
| | | | - Eria A. Rebollar
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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4
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Campos PM, Lucid MK, Ehlers S, Walke JB. Low-level pathogen infection and geographic location correlate with the skin microbiomes of Columbia spotted frogs ( Rana luteiventris) in a montane landscape. CURRENT RESEARCH IN MICROBIAL SCIENCES 2023; 6:100213. [PMID: 38187998 PMCID: PMC10770434 DOI: 10.1016/j.crmicr.2023.100213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2024] Open
Abstract
The skin microbiome of amphibians can influence host susceptibility towards the fungal pathogen Batrachochytrium dendrobatidis (Bd), while simultaneously having the potential to be altered by Bd. Severe Bd infections are known to alter the amphibian skin microbiome; however, little is known about microbiome interactions in amphibians with low infection intensity. In addition to disease dynamics, environmental factors may influence the microbiome. To test for patterns in bacterial diversity based on pathogen infection and environmental factors, 399 Columbia spotted frogs (Rana luteiventris) were sampled throughout northern Idaho and northeastern Washington across two years. Bd prevalence and intensity were measured in 376 frogs, revealing a prevalence of 69%, but generally low infection intensity (Mean = 127 Bd zoospore equivalents among infected frogs). Skin bacterial communities were characterized in 92 frogs using 16S rRNA gene amplicon sequencing. Our results indicated correlations of decreasing Shannon diversity and evenness as infection intensity increased. Latitude was correlated with bacterial richness and Faith's Phylogenetic Diversity measures, indicating increased diversity in northern locations. Beta diversity (UniFrac) analyses revealed that skin microbiomes were distinct between infected and uninfected frogs, and infection intensity had a significant effect on microbiome composition. Site explained the majority of microbiome variation (weighted UniFrac: 57.5%), suggesting a combination of local habitat conditions explain variation, as only small proportions of variation could be explained by year, month, temperature, elevation, and latitude individually. Bacterial genera with potential for Bd-inhibitory properties were found with differential relative abundance in infected and uninfected frogs, with higher Stenotrophomonas and lower Pseudomonas relative abundance observed in infected frogs. Further study may indicate if Bd inhibition by members of the skin microbiome is an influence behind the low infection intensities observed and whether low Bd infection intensities are capable of altering skin microbiome composition.
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Affiliation(s)
- Philip M. Campos
- Department of Biology, Eastern Washington University, 1175 Washington St., Cheney, WA 99004, USA
| | - Michael K. Lucid
- Idaho Department of Fish and Game, 2885 Kathleen Ave., Coeur d'Alene, ID 83815, USA
- Selkirk Wildlife Science, LLC, PO Box 733, Sandpoint, ID 83864, USA
| | - Shannon Ehlers
- Idaho Department of Fish and Game, 2885 Kathleen Ave., Coeur d'Alene, ID 83815, USA
- U.S. Fish and Wildlife Service, 287 Westside Rd., Bonners Ferry, ID 83805, USA
| | - Jenifer B. Walke
- Department of Biology, Eastern Washington University, 1175 Washington St., Cheney, WA 99004, USA
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5
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Fieschi-Méric L, van Leeuwen P, Denoël M, Lesbarrères D. Encouraging news for in situ conservation: Translocation of salamander larvae has limited impacts on their skin microbiota. Mol Ecol 2023. [PMID: 36872055 DOI: 10.1111/mec.16914] [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: 09/05/2022] [Revised: 02/07/2023] [Accepted: 03/02/2023] [Indexed: 03/07/2023]
Abstract
The key role of symbiotic skin bacteria communities in amphibian resistance to emerging pathogens is well recognized, but factors leading to their dysbiosis are not fully understood. In particular, the potential effects of population translocations on the composition and diversity of hosts' skin microbiota have received little attention, although such transfers are widely carried out as a strategy for amphibian conservation. To characterize the potential reorganization of the microbiota over such a sudden environmental change, we conducted a common-garden experiment simulating reciprocal translocations of yellow-spotted salamander larvae across three lakes. We sequenced skin microbiota samples collected before and 15 days after the transfer. Using a database of antifungal isolates, we identified symbionts with known function against the pathogen Batrachochytrium dendrobatidis, a major driver of amphibian declines. Our results indicate an important reorganization of bacterial assemblages throughout ontogeny, with strong changes in composition, diversity and structure of the skin microbiota in both control and translocated individuals over the 15 days of monitoring. Unexpectedly, the diversity and community structure of the microbiota were not significantly affected by the translocation event, thus suggesting a strong resilience of skin bacterial communities to environmental change-at least across the time-window studied here. A few phylotypes were more abundant in the microbiota of translocated larvae, but no differences were found among pathogen-inhibiting symbionts. Taken together, our results support amphibian translocations as a promising strategy for this endangered animal class, with limited impact on their skin microbiota.
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Affiliation(s)
- Léa Fieschi-Méric
- Laboratory of Ecology and Conservation of Amphibians (LECA), Freshwater and OCeanic science Unit of reSearch (FOCUS), Université de Liège, Liège, Belgium.,Biology Department, Laurentian University, Sudbury, Ontario, Canada
| | - Pauline van Leeuwen
- Biology Department, Laurentian University, Sudbury, Ontario, Canada.,Conservation Genetics Laboratory, University de Liège, Liège, Belgium
| | - Mathieu Denoël
- Laboratory of Ecology and Conservation of Amphibians (LECA), Freshwater and OCeanic science Unit of reSearch (FOCUS), Université de Liège, Liège, Belgium
| | - David Lesbarrères
- Biology Department, Laurentian University, Sudbury, Ontario, Canada.,Environment and Climate Change Canada, Ottawa, Ontario, Canada
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6
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Kaganer AW, Ossiboff RJ, Keith NI, Schuler KL, Comizzoli P, Hare MP, Fleischer RC, Gratwicke B, Bunting EM. Immune priming prior to pathogen exposure sheds light on the relationship between host, microbiome and pathogen in disease. ROYAL SOCIETY OPEN SCIENCE 2023; 10:220810. [PMID: 36756057 PMCID: PMC9890126 DOI: 10.1098/rsos.220810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 01/04/2023] [Indexed: 06/18/2023]
Abstract
Dynamic interactions between host, pathogen and host-associated microbiome dictate infection outcomes. Pathogens including Batrachochytrium dendrobatidis (Bd) threaten global biodiversity, but conservation efforts are hindered by limited understanding of amphibian host, Bd and microbiome interactions. We conducted a vaccination and infection experiment using Eastern hellbender salamanders (Cryptobranchus alleganiensis alleganiensis) challenged with Bd to observe infection, skin microbial communities and gene expression of host skin, pathogen and microbiome throughout the experiment. Most animals survived high Bd loads regardless of their vaccination status and vaccination did not affect pathogen load, but host gene expression differed based on vaccination. Oral vaccination (exposure to killed Bd) stimulated immune gene upregulation while topically and sham-vaccinated animals did not significantly upregulate immune genes. In early infection, topically vaccinated animals upregulated immune genes but orally and sham-vaccinated animals downregulated immune genes. Bd increased pathogenicity-associated gene expression in late infection when Bd loads were highest. The microbiome was altered by Bd, but there was no correlation between anti-Bd microbe abundance or richness and pathogen burden. Our observations suggest that hellbenders initially generate a vigorous immune response to Bd, which is ineffective at controlling disease and is subsequently modulated. Interactions with antifungal skin microbiota did not influence disease progression.
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Affiliation(s)
- Alyssa W. Kaganer
- Department of Natural Resources and the Environment, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, 14853, USA
- Smithsonian's National Zoo and Conservation Biology Institute, Washington, DC, 20008, USA
- Cornell Wildlife Health Laboratory, Animal Health Diagnostic Center, Cornell University, Ithaca, NY, 14853, USA
| | - Robert J. Ossiboff
- Cornell Wildlife Health Laboratory, Animal Health Diagnostic Center, Cornell University, Ithaca, NY, 14853, USA
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA
| | - Nicole I. Keith
- Cornell Wildlife Health Laboratory, Animal Health Diagnostic Center, Cornell University, Ithaca, NY, 14853, USA
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
- Biology Department, Hamilton College, Clinton, NY, 13323, USA
| | - Krysten L. Schuler
- Cornell Wildlife Health Laboratory, Animal Health Diagnostic Center, Cornell University, Ithaca, NY, 14853, USA
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
| | - Pierre Comizzoli
- Smithsonian's National Zoo and Conservation Biology Institute, Washington, DC, 20008, USA
| | - Matthew P. Hare
- Department of Natural Resources and the Environment, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, 14853, USA
| | - Robert C. Fleischer
- Smithsonian's National Zoo and Conservation Biology Institute, Washington, DC, 20008, USA
| | - Brian Gratwicke
- Smithsonian's National Zoo and Conservation Biology Institute, Front Royal, VA, 22630, USA
| | - Elizabeth M. Bunting
- Cornell Wildlife Health Laboratory, Animal Health Diagnostic Center, Cornell University, Ithaca, NY, 14853, USA
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
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7
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Crim MJ, Hart ML. Health Monitoring for Laboratory Salamanders. Methods Mol Biol 2023; 2562:41-74. [PMID: 36272067 DOI: 10.1007/978-1-0716-2659-7_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Laboratory animal health monitoring programs are necessary to protect animal health and welfare, the validity of experimental data, and human health against zoonotic infections. Health monitoring programs should be designed based on a risk assessment and knowledge about the biology and transmission of salamander pathogens. Both traditional and molecular diagnostic platforms are available for salamanders, and they provide complementary information. A comprehensive approach to health monitoring leverages the advantages of multiple platforms to provide a more complete picture of colony health and pathogen status. This chapter presents key considerations in the design and implementation of a colony health monitoring program for laboratory salamanders, including protocols for necropsy and sample collection.
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8
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Martínez-Ugalde E, Ávila-Akerberg V, González Martínez TM, Vázquez Trejo M, Zavala Hernández D, Anaya-Morales SL, Rebollar EA. The skin microbiota of the axolotl Ambystoma altamirani is highly influenced by metamorphosis and seasonality but not by pathogen infection. Anim Microbiome 2022; 4:63. [PMID: 36503640 PMCID: PMC9743558 DOI: 10.1186/s42523-022-00215-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 10/16/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Microbiomes have been increasingly recognized as major contributors to host health and survival. In amphibians, bacterial members of the skin microbiota protect their hosts by inhibiting the growth of the fungal pathogen Batrachochytrium dendrobatidis (Bd). Even though several studies describe the influence of biotic and abiotic factors over the skin microbiota, it remains unclear how these symbiotic bacterial communities vary across time and development. This is particularly relevant for species that undergo metamorphosis as it has been shown that host physiology and ecology drastically influence diversity of the skin microbiome. RESULTS We found that the skin bacterial communities of the axolotl A. altamirani are largely influenced by the metamorphic status of the host and by seasonal variation of abiotic factors such as temperature, pH, dissolved oxygen and conductivity. Despite high Bd prevalence in these samples, the bacterial diversity of the skin microbiota did not differ between infected and non-infected axolotls, although relative abundance of particular bacteria were correlated with Bd infection intensity. CONCLUSIONS Our work shows that metamorphosis is a crucial process that shapes skin bacterial communities and that axolotls under different developmental stages respond differently to environmental seasonal variations. Moreover, this study greatly contributes to a better understanding of the factors that shape amphibian skin microbiota, especially in a largely underexplored group like axolotls (Mexican Ambystoma species).
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Affiliation(s)
- Emanuel Martínez-Ugalde
- grid.9486.30000 0001 2159 0001Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Víctor Ávila-Akerberg
- grid.412872.a0000 0001 2174 6731Instituto de Ciencias Agropecuarias y Rurales, Universidad Autónoma del Estado de México, Toluca, Mexico
| | - Tanya M. González Martínez
- grid.9486.30000 0001 2159 0001Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Montserrat Vázquez Trejo
- grid.9486.30000 0001 2159 0001Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Dalia Zavala Hernández
- grid.9486.30000 0001 2159 0001Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Sara Lucia Anaya-Morales
- grid.9486.30000 0001 2159 0001Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico ,grid.251313.70000 0001 2169 2489 Department of Biology, University of Mississippi, Oxford, MS USA
| | - Eria A. Rebollar
- grid.9486.30000 0001 2159 0001Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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9
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Torres-Sánchez M, Longo AV. Linking pathogen-microbiome-host interactions to explain amphibian population dynamics. Mol Ecol 2022; 31:5784-5794. [PMID: 36130047 DOI: 10.1111/mec.16701] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 09/13/2022] [Accepted: 09/16/2022] [Indexed: 01/13/2023]
Abstract
Symbiotic interactions can determine the evolutionary trajectories of host species, influencing genetic variation through selection and changes in demography. In the context of strong selective pressures such as those imposed by infectious diseases, symbionts providing defences could contribute to increase host fitness upon pathogen emergence. Here, we generated genome-wide data of an amphibian species to find evidence of evolutionary pressures driven by two skin symbionts: a batrachochytrid fungal pathogen and an antifungal bacterium. Using demographic modelling, we found evidence of decreased effective population size, probably due to pathogen infections. Additionally, we investigated host genetic associations with infection status, antifungal bacterium abundance and overall microbiome diversity using structural equation models. We uncovered relatively lower nucleotide diversity in infected frogs and potential heterozygote advantage to recruit the candidate beneficial symbiont and fight infections. Our models indicate that environmental conditions have indirect effects on symbiont abundance through both host body traits and microbiome diversity. Likewise, we uncovered a potential offsetting effect among host heterozygosity-fitness correlations, plausibly pointing to different ecological and evolutionary processes among the three species due to dynamic interactions. Our findings revealed that evolutionary pressures not only arise from the pathogen but also from the candidate beneficial symbiont, and both interactions shape the genetics of the host. Our results advance knowledge about multipartite symbiotic relationships and provide a framework to model ecological and evolutionary dynamics in wild populations. Finally, our study approach can be applied to inform conservation actions such as bioaugmentation strategies for other imperilled amphibians affected by infectious diseases.
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Affiliation(s)
| | - Ana V Longo
- Department of Biology, University of Florida, Gainesville, Florida, USA
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10
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Wuerthner VP, Hua J, Hernández‐Gómez O. Life stage and proximity to roads shape the skin microbiota of eastern newts (Notophthalmus viridescens). Environ Microbiol 2022; 24:3954-3965. [PMID: 35355399 PMCID: PMC9790580 DOI: 10.1111/1462-2920.15986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/20/2022] [Accepted: 03/22/2022] [Indexed: 12/30/2022]
Abstract
Host-associated microbiomes play an essential role in the health of organisms, including immune system activation, metabolism and energy uptake. It is well established that microbial communities differ depending on the life stage and natural history of the organism. However, the effects of life stage and natural history on microbial communities may also be influenced by human activities. We investigated the effects of amphibian life stage (terrestrial eft vs. aquatic adult) and proximity to roadways on newt skin bacterial communities. We found that the eft and adult life stages differed in bacterial community composition; however, the effects of roads on community composition were more evident in the terrestrial eft stage compared to the aquatic adult stage. Terrestrial efts sampled close to roads possessed richer communities than those living further away from the influence of roads. When accounting for amplicon sequence variants with predicted antifungal capabilities, in the adult life stage, we observed a decrease in anti-fungal bacteria with distance to roads. In contrast, in the eft stage, we found an increase in anti-fungal bacteria with distance to roads. Our results highlight the need to consider the effects of human activities when evaluating how host-associated microbiomes differ across life stages of wildlife.
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Affiliation(s)
| | - Jessica Hua
- Department of Biological SciencesBinghamton UniversityBinghamtonNY,Department of Forest and Wildlife EcologyUniversity of Wisconsin‐MadisonMadisonWI
| | - Obed Hernández‐Gómez
- Department of Environmental Sciences, Policy, and ManagementUniversity of California‐BerkeleyBerkeleyCA,Department of Natural Sciences and MathematicsDominican University of CaliforniaSan RafaelCA
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11
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Le Sage EH, Ohmer MEB, LaBumbard BC, Altman KA, Reinert LK, Bednark JG, Bletz MC, Inman B, Lindauer A, McDonnell NB, Parker SK, Skerlec SM, Wantman T, Rollins‐Smith LA, Woodhams DC, Voyles J, Richards‐Zawacki CL. Localized carry‐over effects of pond drying on survival, growth, and pathogen defenses in amphibians. Ecosphere 2022. [DOI: 10.1002/ecs2.4224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Emily H. Le Sage
- Department of Pathology, Microbiology and Immunology Vanderbilt University School of Medicine Nashville Tennessee USA
| | - Michel E. B. Ohmer
- Department of Biological Sciences University of Pittsburgh Pittsburgh Pennsylvania USA
| | | | - Karie A. Altman
- Department of Biological Sciences University of Pittsburgh Pittsburgh Pennsylvania USA
| | - Laura K. Reinert
- Department of Pathology, Microbiology and Immunology Vanderbilt University School of Medicine Nashville Tennessee USA
| | - Jeffery G. Bednark
- Department of Biological Sciences University of Pittsburgh Pittsburgh Pennsylvania USA
| | - Molly C. Bletz
- Department of Biology University of Massachusetts Boston Massachusetts USA
| | - Brady Inman
- Department of Pathology, Microbiology and Immunology Vanderbilt University School of Medicine Nashville Tennessee USA
- Department of Biology University of Massachusetts Boston Massachusetts USA
| | - Alexa Lindauer
- Department of Biology University of Nevada Reno Nevada USA
| | - Nina B. McDonnell
- Department of Biology University of Massachusetts Boston Massachusetts USA
| | - Sadie K. Parker
- Department of Biological Sciences University of Pittsburgh Pittsburgh Pennsylvania USA
| | - Samantha M. Skerlec
- Department of Biological Sciences University of Pittsburgh Pittsburgh Pennsylvania USA
| | - Trina Wantman
- Department of Biological Sciences University of Pittsburgh Pittsburgh Pennsylvania USA
| | - Louise A. Rollins‐Smith
- Department of Pathology, Microbiology and Immunology Vanderbilt University School of Medicine Nashville Tennessee USA
- Department of Biological Sciences Vanderbilt University Nashville Tennessee USA
- Department of Pediatrics Vanderbilt University School of Medicine Nashville Tennessee USA
| | | | - Jamie Voyles
- Department of Biology University of Nevada Reno Nevada USA
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12
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Peixoto RS, Voolstra CR, Sweet M, Duarte CM, Carvalho S, Villela H, Lunshof JE, Gram L, Woodhams DC, Walter J, Roik A, Hentschel U, Thurber RV, Daisley B, Ushijima B, Daffonchio D, Costa R, Keller-Costa T, Bowman JS, Rosado AS, Reid G, Mason CE, Walke JB, Thomas T, Berg G. Harnessing the microbiome to prevent global biodiversity loss. Nat Microbiol 2022; 7:1726-1735. [PMID: 35864220 DOI: 10.1038/s41564-022-01173-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 06/14/2022] [Indexed: 01/21/2023]
Abstract
Global biodiversity loss and mass extinction of species are two of the most critical environmental issues the world is currently facing, resulting in the disruption of various ecosystems central to environmental functions and human health. Microbiome-targeted interventions, such as probiotics and microbiome transplants, are emerging as potential options to reverse deterioration of biodiversity and increase the resilience of wildlife and ecosystems. However, the implementation of these interventions is urgently needed. We summarize the current concepts, bottlenecks and ethical aspects encompassing the careful and responsible management of ecosystem resources using the microbiome (termed microbiome stewardship) to rehabilitate organisms and ecosystem functions. We propose a real-world application framework to guide environmental and wildlife probiotic applications. This framework details steps that must be taken in the upscaling process while weighing risks against the high toll of inaction. In doing so, we draw parallels with other aspects of contemporary science moving swiftly in the face of urgent global challenges.
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Affiliation(s)
- Raquel S Peixoto
- Red Sea Research Center (RSRC), Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
| | - Christian R Voolstra
- Red Sea Research Center (RSRC), Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Michael Sweet
- Aquatic Research Facility, Environmental Sustainability Research Centre, University of Derby, Derby, UK
| | - Carlos M Duarte
- Red Sea Research Center (RSRC), Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.,Computational Bioscience Research Center (CBRC), Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Susana Carvalho
- Red Sea Research Center (RSRC), Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Helena Villela
- Red Sea Research Center (RSRC), Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Jeantine E Lunshof
- Department of Global Health and Social Medicine, Center for Bioethics, Harvard Medical School, Boston, MA, USA.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Lone Gram
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Douglas C Woodhams
- Department of Biology, University of Massachusetts Boston, Boston, MA, USA.,Smithsonian Tropical Research Institute, Panama City, Panama
| | - Jens Walter
- APC Microbiome Ireland, School of Microbiology, and Department of Medicine, University College Cork, Cork, Ireland
| | - Anna Roik
- Helmholtz Institute for Functional Marine Biodiversity (HIFMB), Oldenburg, Germany
| | - Ute Hentschel
- RD3 Marine Symbioses, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | | | - Brendan Daisley
- Lawson Health Research Institute, University of Western Ontario, London, Ontario, Canada
| | - Blake Ushijima
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, USA
| | - Daniele Daffonchio
- Red Sea Research Center (RSRC), Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Rodrigo Costa
- Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Tina Keller-Costa
- Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Jeff S Bowman
- Scripps Institution of Oceanography, University of California San Diego, San Diego, CA, USA
| | - Alexandre S Rosado
- Red Sea Research Center (RSRC), Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Gregor Reid
- Lawson Health Research Institute, University of Western Ontario, London, Ontario, Canada
| | | | - Jenifer B Walke
- Department of Biology, Eastern Washington University, Cheney, WA, USA
| | - Torsten Thomas
- Centre for Marine Science and Innovation and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
| | - Gabriele Berg
- Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria.,University of Postdam and Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Potsdam, Germany
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13
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Basanta MD, Rebollar EA, García-Castillo MG, Parra Olea G. Comparative Analysis of Skin Bacterial Diversity and Its Potential Antifungal Function Between Desert and Pine Forest Populations of Boreal Toads Anaxyrus boreas. MICROBIAL ECOLOGY 2022; 84:257-266. [PMID: 34427721 DOI: 10.1007/s00248-021-01845-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 08/14/2021] [Indexed: 06/13/2023]
Abstract
The skin microbiome in amphibians has gained a lot of attention as some of its members play a protective role against pathogens such as the fungus Batrachochytrium dendrobatidis (Bd). The composition of skin bacterial communities has been suggested as one of the factors explaining differences in susceptibility to Bd among amphibian species and populations. The boreal toad Anaxyrus boreas is known to be susceptible to Bd, and severe population declines in its southeastern range have been documented. However, throughout A. boreas distribution, populations present differences in susceptibility to Bd infections which may be associated with differences in skin microbial diversity. This study compared the skin bacterial diversity and Bd infection levels of A. boreas in one desert population and one pine forest population from Baja California, Mexico. We found that desert and pine forest toad populations exhibit differences in skin bacterial community structure but show similar Bd infection levels. Using a predictive method, we found that the abundance of bacteria with potential Bd-inhibitory properties differed between uninfected and infected individuals but not between populations. Our data suggest that several bacteria in the skin community may be offering protection from Bd infections in these A. boreas populations. This study provides foundational evidence for future studies seeking to understand the skin-microbial variation among boreal toads' populations and its relation with Bd susceptibility.
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Affiliation(s)
- M Delia Basanta
- Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, México
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Eria A Rebollar
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Mirna G García-Castillo
- Universidad Politécnica de Huatusco, Huatusco, Veracruz, México
- Facultad de Ciencias Biológicas y Agropecuarias Región: Orizaba-Córdoba, Universidad Veracruzana, Amatlán de Los Reyes, Veracruz, México
| | - Gabriela Parra Olea
- Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, México.
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14
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Inhibitory Bacterial Diversity and Mucosome Function Differentiate Susceptibility of Appalachian Salamanders to Chytrid Fungal Infection. Appl Environ Microbiol 2022; 88:e0181821. [PMID: 35348389 PMCID: PMC9040618 DOI: 10.1128/aem.01818-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Mucosal defenses are crucial in animals for protection against pathogens and predators. Host defense peptides (antimicrobial peptides, AMPs) as well as skin-associated microbes are key components of mucosal immunity, particularly in amphibians. We integrate microbiology, molecular biology, network-thinking, and proteomics to understand how host and microbially derived products on amphibian skin (referred to as the mucosome) serve as pathogen defenses. We studied defense mechanisms against chytrid pathogens, Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal), in four salamander species with different Batrachochytrium susceptibilities. Bd infection was quantified using qPCR, mucosome function (i.e., ability to kill Bd or Bsal zoospores in vitro), skin bacterial communities using 16S rRNA gene amplicon sequencing, and the role of Bd-inhibitory bacteria in microbial networks across all species. We explored the presence of candidate-AMPs in eastern newts and red-backed salamanders. Eastern newts had the highest Bd prevalence and mucosome function, while red-back salamanders had the lowest Bd prevalence and mucosome function, and two-lined salamanders and seal salamanders were intermediates. Salamanders with highest Bd infection intensity showed greater mucosome function. Bd infection prevalence significantly decreased as putative Bd-inhibitory bacterial richness and relative abundance increased on hosts. In co-occurrence networks, some putative Bd-inhibitory bacteria were found as hub-taxa, with red-backs having the highest proportion of protective hubs and positive associations related to putative Bd-inhibitory hub bacteria. We found more AMP candidates on salamanders with lower Bd susceptibility. These findings suggest that salamanders possess distinct innate mechanisms that affect chytrid fungi. IMPORTANCE How host mucosal defenses interact, and influence disease outcome is critical in understanding host defenses against pathogens. A more detailed understanding is needed of the interactions between the host and the functioning of its mucosal defenses in pathogen defense. This study investigates the variability of chytrid susceptibility in salamanders and the innate defenses each species possesses to mediate pathogens, thus advancing the knowledge toward a deeper understanding of the microbial ecology of skin-associated bacteria and contributing to the development of bioaugmentation strategies to mediate pathogen infection and disease. This study improves the understanding of complex immune defense mechanisms in salamanders and highlights the potential role of the mucosome to reduce the probability of Bd disease development and that putative protective bacteria may reduce likelihood of Bd infecting skin.
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15
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Chen MY, Kueneman JG, González A, Humphrey G, Knight R, McKenzie VJ. Predicting fungal infection rate and severity with skin-associated microbial communities on amphibians. Mol Ecol 2022; 31:2140-2156. [PMID: 35076975 DOI: 10.1111/mec.16372] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 12/16/2021] [Accepted: 01/18/2022] [Indexed: 11/28/2022]
Abstract
Pathogen success (risk and severity) is influenced by host-associated microbiota, but the degree to which variation in microbial community traits predict future infection presence/absence (risk) and load (severity) for the host is unknown. We conducted a time-series experiment by sampling the skin-associated bacterial communities of five amphibian species before and after exposure to the fungal pathogen, Batrachochytrium dendrobaditis (Bd). We ask whether microbial community traits are predictors of, or are affected by, Bd infection risk and intensity. Our results show that richness of putative Bd-inhibitory bacteria strongly predicts infection risk, while the proportion of putative Bd-inhibitory bacteria predicts future infection intensity. Variation in microbial community composition is high across time and individual, and bacterial prevalence is low. Our findings demonstrate how ecological community traits of host-associated microbiota may be used to predict infection risk by pathogenic microbes.
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Affiliation(s)
- Melissa Y Chen
- Department of Ecology and Evolutionary Biology, University of Colorado, Ramaley N-122, UCB 334, Boulder, CO, 80309, USA
| | - Jordan G Kueneman
- Smithsonian Tropical Research Institute, Luis Clement Avenue, Bldg. 401 Tupper, Balboa Ancon, Panama, Republic of Panama
| | - Antonio González
- Department of Pediatrics, Bioengineering and Computer Science and Engineering, and Center for Microbiome Innovation, University of California, Gilman Drive, La Jolla, San Diego, CA, 92093, USA
| | - Greg Humphrey
- Department of Pediatrics, Bioengineering and Computer Science and Engineering, and Center for Microbiome Innovation, University of California, Gilman Drive, La Jolla, San Diego, CA, 92093, USA
| | - Rob Knight
- Department of Pediatrics, Bioengineering and Computer Science and Engineering, and Center for Microbiome Innovation, University of California, Gilman Drive, La Jolla, San Diego, CA, 92093, USA
| | - Valerie J McKenzie
- Department of Ecology and Evolutionary Biology, University of Colorado, Ramaley N-122, UCB 334, Boulder, CO, 80309, USA
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16
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Basanta MD, Rebollar EA, García-Castillo MG, Rosenblum EB, Byrne AQ, Piovia-Scott J, Parra-Olea G. Genetic variation of Batrachochytrium dendrobatidis is linked to skin bacterial diversity in the Pacific treefrog Hyliola regilla (hypochondriaca). Environ Microbiol 2021; 24:494-506. [PMID: 34959256 DOI: 10.1111/1462-2920.15861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 11/22/2021] [Accepted: 11/27/2021] [Indexed: 11/29/2022]
Abstract
Symbiotic bacterial communities are crucial to combating infections and contribute to host health. The amphibian skin microbiome plays an important role in protecting their hosts against pathogens such as Batrachochytrium dendrobatidis (Bd), one of the causative agents of chytridiomycosis, which is responsible for dramatic amphibian population declines worldwide. Although symbiotic skin bacteria are known to inhibit Bd growth, an understanding of the relationship between Bd genetic variability, environmental conditions, and skin bacterial communities is limited. Therefore, we examined the associations between Bd infection load, Bd genetic diversity and skin bacterial communities in five populations of Hyliola regilla (hypochondriaca) from environmentally contrasting sites in Baja California, Mexico. We observed differences in Bd genetics and infection load among sites and environments. Genetic analysis of Bd isolates revealed patterns of spatial structure corresponding to the five sites sampled. Amphibian skin bacterial diversity and community structure differed among environments and sites. Bacterial community composition was correlated with Bd genetic differences and infection load, with specific bacterial taxa enriched on infected and un-infected frogs. Our results indicate that skin-associated bacteria and Bd strains likely interact on the host skin, with consequences for microbial community structure and Bd infection intensity.
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Affiliation(s)
- María Delia Basanta
- Instituto de Biología, Universidad Nacional Autónoma de México, Mexico.,Posgrado en Ciencias Biológicas, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, AP 70-153, C.P. 04510, Mexico.,Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Eria A Rebollar
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Mirna G García-Castillo
- Universidad Politécnica de Huatusco, Huatusco, Veracruz, Mexico.,Universidad Veracruzana, Facultad de Ciencias Biológicas y Agropecuarias Región: Orizaba-Córdoba, Amatlán de los Reyes, Veracruz, Mexico
| | - Erica Bree Rosenblum
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, USA.,Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
| | - Allison Q Byrne
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, USA.,Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
| | - Jonah Piovia-Scott
- School of Biological Sciences, Washington State University, Vancouver, WA, USA
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17
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Ellison S, Knapp R, Vredenburg V. Longitudinal patterns in the skin microbiome of wild, individually marked frogs from the Sierra Nevada, California. ISME COMMUNICATIONS 2021; 1:45. [PMID: 37938625 PMCID: PMC9723788 DOI: 10.1038/s43705-021-00047-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 08/04/2021] [Accepted: 08/17/2021] [Indexed: 05/29/2023]
Abstract
The amphibian skin microbiome has been the focus of numerous studies because of the protective effects that some bacteria provide against the pathogenic fungus Batrachochytrium dendrobatidis, which has caused a global panzootic among amphibians. However, the mechanisms driving community structure and function in the amphibian skin microbiome are still poorly understood, and longitudinal analyses of the skin microbiome have not yet been conducted in wild populations. In this study, we investigate longitudinal patterns in the skin microbiome of 19 individually marked adult frogs from two wild populations of the endangered Sierra Nevada yellow-legged frog (Rana sierrae), sampled over the course of 2 years. We found that individuals with low bacterial diversity (dominated by order Burkhorderiales) had significantly more stable bacterial communities than those with higher diversity. Amplicon sequence variants (ASVs) with high relative abundance were significantly less transient than those with low relative abundance, and ASVs with intermediate-level relative abundances experienced the greatest volatility over time. Based on these results, we suggest that efforts to develop probiotic treatments to combat B. dendrobatidis should focus on bacteria that are found at high relative abundances in some members of a population, as these strains are more likely to persist and remain stable in the long term.
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Affiliation(s)
- Silas Ellison
- Department of Biology, San Francisco State University, San Francisco, California, USA.
| | - Roland Knapp
- Sierra Nevada Aquatic Research Laboratory, University of California, Mammoth Lakes, CA, USA
| | - Vance Vredenburg
- Department of Biology, San Francisco State University, San Francisco, California, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, California, USA
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18
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TEMPERATURE AS A DRIVER OF THE PATHOGENICITY AND VIRULENCE OF AMPHIBIAN CHYTRID FUNGUS BATRACHOCHYTRIUM DENDROBATIDIS: A SYSTEMATIC REVIEW. J Wildl Dis 2021; 57:477-494. [PMID: 34019674 DOI: 10.7589/jwd-d-20-00105] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 02/10/2021] [Indexed: 11/20/2022]
Abstract
Chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), is a leading cause of global amphibian declines. Severe infections with Bd can lead to cardiac arrest, and mass deaths during epidemics have been reported. Temperature, pH, salinity, and moisture are important determinants of the survival, growth, reproduction, and pathogenicity of Bd, as well as its effect on amphibian populations. Here, we synthesize current knowledge on the role of temperature as a driver of the pathogenicity and virulence of Bd to better understand the effects of temperature on amphibian defense mechanisms against infection. This review advises on research direction and management approaches to benefit amphibian populations affected by Bd. We conclude by offering guidelines for four levels of temperature monitoring in amphibian field studies to improve consistency between studies: regional climate, habitat, microhabitat, and amphibian host.
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19
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Medina D, Greenspan SE, Carvalho T, Becker CG, Toledo LF. Co-infecting pathogen lineages have additive effects on host bacterial communities. FEMS Microbiol Ecol 2021; 97:6134751. [PMID: 33580951 DOI: 10.1093/femsec/fiab030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 02/11/2021] [Indexed: 01/08/2023] Open
Abstract
Amphibian skin bacteria may confer protection against the fungus Batrachochytrium dendrobatidis (Bd), but responses of skin bacteria to different Bd lineages are poorly understood. The global panzootic lineage (Bd-GPL) has caused amphibian declines and extinctions globally. However, other lineages are enzootic (Bd-Asia-2/Brazil). Increased contact rates between Bd-GPL and enzootic lineages via globalization pose unknown consequences for host-microbiome-pathogen dynamics. We conducted a laboratory experiment and used 16S rRNA amplicon-sequencing to assess: (i) whether two lineages (Bd-Asia-2/Brazil and Bd-GPL) and their recombinant, in single and mixed infections, differentially affect amphibian skin bacteria; (ii) and the changes associated with the transition to laboratory conditions. We determined no clear differences in bacterial diversity among Bd treatments, despite differences in infection intensity. However, we observed an additive effect of mixed infections on bacterial alpha diversity and a potentially antagonistic interaction between Bd genotypes. Additionally, observed changes in community composition suggest a higher ability of Bd-GPL to alter skin bacteria. Lastly, we observed a drastic reduction in bacterial diversity and a change in community structure in laboratory conditions. We provide evidence for complex interactions between Bd genotypes and amphibian skin bacteria during coinfections, and expand on the implications of experimental conditions in ecological studies.
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Affiliation(s)
- Daniel Medina
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas, R. Monteiro Lobato, 255 - CEP 13083-862, Campinas, São Paulo, Brazil.,Sistema Nacional de Investigación, SENACYT, Building 205, City of Knowledge, Clayton, Panama, Republic of Panama
| | - Sasha E Greenspan
- Department of Biological Sciences, The University of Alabama, 1339 Science and Engineering Complex, Tuscaloosa 35487, Alabama, USA
| | - Tamilie Carvalho
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas, R. Monteiro Lobato, 255 - CEP 13083-862, Campinas, São Paulo, Brazil
| | - C Guilherme Becker
- Department of Biological Sciences, The University of Alabama, 1339 Science and Engineering Complex, Tuscaloosa 35487, Alabama, USA
| | - Luís Felipe Toledo
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas, R. Monteiro Lobato, 255 - CEP 13083-862, Campinas, São Paulo, Brazil
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20
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Winter is coming-Temperature affects immune defenses and susceptibility to Batrachochytrium salamandrivorans. PLoS Pathog 2021; 17:e1009234. [PMID: 33600433 PMCID: PMC7891748 DOI: 10.1371/journal.ppat.1009234] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 12/08/2020] [Indexed: 12/24/2022] Open
Abstract
Environmental temperature is a key factor driving various biological processes, including immune defenses and host-pathogen interactions. Here, we evaluated the effects of environmental temperature on the pathogenicity of the emerging fungal pathogen, Batrachochytrium salamandrivorans (Bsal), using controlled laboratory experiments, and measured components of host immune defense to identify regulating mechanisms. We found that adult and juvenile Notophthalmus viridescens died faster due to Bsal chytridiomycosis at 14°C than at 6 and 22°C. Pathogen replication rates, total available proteins on the skin, and microbiome composition likely drove these relationships. Temperature-dependent skin microbiome composition in our laboratory experiments matched seasonal trends in wild N. viridescens, adding validity to these results. We also found that hydrophobic peptide production after two months post-exposure to Bsal was reduced in infected animals compared to controls, perhaps due to peptide release earlier in infection or impaired granular gland function in diseased animals. Using our temperature-dependent susceptibility results, we performed a geographic analysis that revealed N. viridescens populations in the northeastern United States and southeastern Canada are at greatest risk for Bsal invasion, which shifted risk north compared to previous assessments. Our results indicate that environmental temperature will play a key role in the epidemiology of Bsal and provide evidence that temperature manipulations may be a viable disease management strategy. In 2010, a new skin-eating fungus, Batrachochytrium salamandrivorans (Bsal), was discovered killing salamanders in the Netherlands. Since then, the pathogen has spread to other European countries. Bsal is believed to be from Asia and is being translocated through the international trade of amphibians. To our knowledge, Bsal has not arrived to North America. As a proactive strategy for disease control, we evaluated how a range of environmental temperatures in North America could affect invasion risk of Bsal into a widely distributed salamander species, the eastern newt (Notophthalmus viridescens). Our results show that northeastern USA, southeastern Canada, and the higher elevations of the Appalachian Mountains have the greatest likelihood of Bsal invasion, when temperature-dependent susceptibility is included in risk analyses. Changes in eastern newt susceptibility to Bsal infection associated with temperature are likely an interaction between pathogen replication rate and host immune defenses, including changes in skin microbiome composition and the host’s ability to produce Bsal-killing proteins on the skin. Our study provides new insights into how latitude, elevation and season can impact the epidemiology of Bsal, and suggests that strategies that manipulate microclimate of newt habitats could be useful in managing Bsal outbreaks and that climate change will impact Bsal invasion probability.
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21
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Douglas AJ, Hug LA, Katzenback BA. Composition of the North American Wood Frog (Rana sylvatica) Bacterial Skin Microbiome and Seasonal Variation in Community Structure. MICROBIAL ECOLOGY 2021; 81:78-92. [PMID: 32613267 DOI: 10.1007/s00248-020-01550-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
While a number of amphibian skin microbiomes have been characterized, it is unclear how these communities might vary in response to seasonal changes in the environment and the corresponding behaviors that many amphibians exhibit. Given recent studies demonstrating the importance of the skin microbiome in frog innate immune defense against pathogens, investigating how changes in the environment impact the microbial species present will provide a better understanding of conditions that may alter host susceptibility to pathogens in their environment. We sampled the bacterial skin microbiome of North American wood frogs (Rana sylvatica) from two breeding ponds in the spring, along with the bacterial community present in their vernal breeding pools, and frogs from the nearby forest floor in the summer and fall to determine whether community composition differs by sex, vernal pond site, or temporally across season (spring, summer, fall). Taxon relative abundance data reveals a profile of bacterial phyla similar to those previously described on anuran skin, with Proteobacteria, Bacteroidetes, and Actinobacteria dominating the wood frog skin microbiome. Our results indicate that sex had no significant effect on skin microbiota diversity; however, this may be due to our limited female frog sample size. Vernal pool site had a small but significant effect on skin microbiota, but skin-associated communities were more similar to each other than to the communities observed in the frogs' respective pond water. Across seasons, diversity analyses suggest that there are significant differences between the bacterial skin microbiome of frogs from spring and summer/fall groups while the average α-diversity per frog remained consistent. These results illustrate seasonal variation in wood frog skin microbiome structure and highlight the importance of considering temporal trends in an amphibian microbiome, particularly for species whose life history requires recurrent shifts in habitat and behavior.
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Affiliation(s)
- Alexander J Douglas
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - Laura A Hug
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - Barbara A Katzenback
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
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22
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Ruthsatz K, Lyra ML, Lambertini C, Belasen AM, Jenkinson TS, da Silva Leite D, Becker CG, Haddad CFB, James TY, Zamudio KR, Toledo LF, Vences M. Skin microbiome correlates with bioclimate and Batrachochytrium dendrobatidis infection intensity in Brazil's Atlantic Forest treefrogs. Sci Rep 2020; 10:22311. [PMID: 33339839 PMCID: PMC7749163 DOI: 10.1038/s41598-020-79130-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 12/04/2020] [Indexed: 12/20/2022] Open
Abstract
In Brazil’s Atlantic Forest (AF) biodiversity conservation is of key importance since the fungal pathogen Batrachochytrium dendrobatidis (Bd) has led to the rapid loss of amphibian populations here and worldwide. The impact of Bd on amphibians is determined by the host's immune system, of which the skin microbiome is a critical component. The richness and diversity of such cutaneous bacterial communities are known to be shaped by abiotic factors which thus may indirectly modulate host susceptibility to Bd. This study aimed to contribute to understanding the environment-host–pathogen interaction determining skin bacterial communities in 819 treefrogs (Anura: Hylidae and Phyllomedusidae) from 71 species sampled across the AF. We investigated whether abiotic factors influence the bacterial community richness and structure on the amphibian skin. We further tested for an association between skin bacterial community structure and Bd co-occurrence. Our data revealed that temperature, precipitation, and elevation consistently correlate with richness and diversity of the skin microbiome and also predict Bd infection status. Surprisingly, our data suggest a weak but significant positive correlation of Bd infection intensity and bacterial richness. We highlight the prospect of future experimental studies on the impact of changing environmental conditions associated with global change on environment-host–pathogen interactions in the AF.
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Affiliation(s)
- Katharina Ruthsatz
- Institute of Zoology, Universität Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany. .,Zoological Institute, Technische Universität Braunschweig, Mendelssohnstraße 4, 38106, Brunswick, Germany.
| | - Mariana L Lyra
- Laboratório de Herpetologia, Depto de Biodiversidade, Instituto de Biociências and Centro de Aquicultura (CAUNESP), Universidade Estadual Paulista - UNESP, Rio Claro, São Paulo, Brazil
| | - Carolina Lambertini
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, 13083-862, Brazil
| | - Anat M Belasen
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14853-2701, USA
| | - Thomas S Jenkinson
- Department of Wildlife, Fish and Conservation Biology, University of California, Davis, Davis, CA, USA
| | - Domingos da Silva Leite
- Laboratório de Antígenos Bacterianos II, Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas, Caixa Postal 6109, Campinas, São Paulo, CEP 13083-862, Brazil
| | - C Guilherme Becker
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL, 35847, USA
| | - Célio F B Haddad
- Laboratório de Herpetologia, Depto de Biodiversidade, Instituto de Biociências and Centro de Aquicultura (CAUNESP), Universidade Estadual Paulista - UNESP, Rio Claro, São Paulo, Brazil
| | - Timothy Y James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Kelly R Zamudio
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14853-2701, USA
| | - Luís Felipe Toledo
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, 13083-862, Brazil
| | - Miguel Vences
- Zoological Institute, Technische Universität Braunschweig, Mendelssohnstraße 4, 38106, Brunswick, Germany
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23
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Jiménez RR, Alvarado G, Sandoval J, Sommer S. Habitat disturbance influences the skin microbiome of a rediscovered neotropical-montane frog. BMC Microbiol 2020; 20:292. [PMID: 32962670 PMCID: PMC7509932 DOI: 10.1186/s12866-020-01979-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 09/15/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The skin microbiome serves as a first line defense against pathogens in vertebrates. In amphibians, it has the potential to protect against the chytrid fungus Batrachochytrium dendrobatis (Bd), a likely agent of amphibian declines. Alteration of the microbiome associated with unfavorable environmental changes produced by anthropogenic activities may make the host more susceptible to pathogens. Some amphibian species that were thought to be "extinct" have been rediscovered years after population declines in the late 1980s probably due to evolved Bd-resistance and are now threatened by anthropogenic land-use changes. Understanding the effects of habitat disturbance on the host skin microbiome is relevant for understanding the health of these species, along with its susceptibility to pathogens such as Bd. Here, we investigate the influence of habitat alteration on the skin bacterial communities as well as specifically the putative Bd-inhibitory bacterial communities of the montane frog Lithobates vibicarius. This species, after years of not being observed, was rediscovered in small populations inhabiting undisturbed and disturbed landscapes, and with continuous presence of Bd. RESULTS We found that cutaneous bacterial communities of tadpoles and adults differed between undisturbed and disturbed habitats. The adults from disturbed habitats exhibited greater community dispersion than those from undisturbed habitats. We observed a higher richness of putative Bd-inhibitory bacterial strains in adults from disturbed habitats than in those from undisturbed habitats, as well as a greater number of these potential protective bacteria with a high relative abundance. CONCLUSIONS Our findings support the microbial "Anna Karenina principle", in which disturbance is hypothesized to cause greater microbial dispersion in communities, a so-called dysbiosis, which is a response of animal microbiomes to stress factors that decrease the ability of the host or its microbiome to regulate community composition. On the positive side, the high richness and relative abundance of putative Bd-inhibitory bacteria may indicate the development of a defense mechanism that enhances Bd-protection, attributed to a co-occurrence of more than 30-years of host and pathogen in these disturbed habitats. Our results provide important insight into the influence of human-modified landscapes on the skin microbiome and health implications of Bd-survivor species.
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Affiliation(s)
- Randall R Jiménez
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Albert-Einstein Allee 11, 89069, Ulm, Germany.
| | - Gilbert Alvarado
- Laboratory of Comparative Wildlife Pathology, School of Veterinary Medicine and Animal Sciences, University of São Paulo, Av. Orlando Marques de Paiva 87, São Paulo, Brazil
- Laboratory of Experimental and Comparative Pathology (LAPECOM), Biology School, University of Costa Rica, San José, Costa Rica
| | - José Sandoval
- Laboratory of Experimental and Comparative Pathology (LAPECOM), Biology School, University of Costa Rica, San José, Costa Rica
| | - Simone Sommer
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Albert-Einstein Allee 11, 89069, Ulm, Germany
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24
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Rebollar EA, Martínez-Ugalde E, Orta AH. The Amphibian Skin Microbiome and Its Protective Role Against Chytridiomycosis. HERPETOLOGICA 2020. [DOI: 10.1655/0018-0831-76.2.167] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Eria A. Rebollar
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, México
| | - Emanuel Martínez-Ugalde
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, México
| | - Alberto H. Orta
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, México
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25
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Barnhart KL, Bletz MC, LaBumbard BC, Tokash-Peters AG, Gabor CR, Woodhams DC. Batrachochytrium salamandrivorans ELICITS ACUTE STRESS RESPONSE IN SPOTTED SALAMANDERS BUT NOT INFECTION OR MORTALITY. Anim Conserv 2020; 23:533-546. [PMID: 33071596 DOI: 10.1111/acv.12565] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The emerging fungal pathogen Batrachochytrium salamandrivorans (Bsal) is a major threat to amphibian species worldwide with potential to infect many species if it invades salamander biodiversity hotspots in the Americas. Bsal can cause the disease chytridiomycosis, and it is important to assess the risk of Bsal-induced chytridiomycosis to species in North America. We evaluated the susceptibility to Bsal of the common and widespread spotted salamander, Ambystoma maculatum, across life history stages and monitored the effect of Bsal exposure on growth rate and response of the stress hormone, corticosterone. We conclude that spotted salamanders appear resistant to Bsal because they showed no indication of disease or infection, and experienced minor effects on growth upon exposure. While we focused on a single population for this study, results were consistent across conditions of exposure including high or repeated doses of Bsal, life-stage at exposure, environmental conditions including two temperatures and two substrates, and promoting pathogen infectivity by conditioning Bsal cultures with thyroid hormone. Exposure to high levels of Bsal elicited an acute but not chronic increase in corticosterone in spotted salamanders, and reduced growth. We hypothesize that the early acute increase in corticosterone facilitated mounting an immune response to the pathogen, perhaps through immunoredistribution to the skin, but further study is needed to determine immune responses to Bsal. These results will contribute to development of appropriate Bsal management plans to conserve species at risk of emerging disease.
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Affiliation(s)
- Kelly L Barnhart
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Molly C Bletz
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Brandon C LaBumbard
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Amanda G Tokash-Peters
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
| | - Caitlin R Gabor
- Texas State University, Department of Biology, 601 University Drive, San Marcos, TX 78666
| | - Douglas C Woodhams
- University of Massachusetts Boston, Department of Biology, 100 William T Morrissey Blvd, Boston, MA 02125
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26
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Harrison XA, Sewell T, Fisher M, Antwis RE. Designing Probiotic Therapies With Broad-Spectrum Activity Against a Wildlife Pathogen. Front Microbiol 2020; 10:3134. [PMID: 32038568 PMCID: PMC6987264 DOI: 10.3389/fmicb.2019.03134] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 12/26/2019] [Indexed: 11/24/2022] Open
Abstract
Host-associated microbes form an important component of immunity that protect against infection by pathogens. Treating wild individuals with these protective microbes, known as probiotics, can reduce rates of infection and disease in both wild and captive settings. However, the utility of probiotics for tackling wildlife disease requires that they offer consistent protection across the broad genomic variation of the pathogen that hosts can encounter in natural settings. Here we develop multi-isolate probiotic consortia with the aim of effecting broad-spectrum inhibition of growth of the lethal amphibian pathogen Batrachochytrium dendrobatidis (Bd) when tested against nine Bd isolates from two distinct lineages. Though we achieved strong growth inhibition between 70 and 100% for seven Bd isolates, two isolates appeared consistently resistant to inhibition, irrespective of probiotic strategy employed. We found no evidence that genomic relatedness of the chytrid predicted similarity of inhibition scores, nor that increasing the genetic diversity of the bacterial consortia could offer stronger inhibition of pathogen growth, even for the two resistant isolates. Our findings have important consequences for the application of probiotics to mitigate wildlife diseases in the face of extensive pathogen genomic variation.
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Affiliation(s)
- Xavier A Harrison
- Institute of Zoology, Zoological Society of London, London, United Kingdom.,Centre for Ecology and Conservation, University of Exeter, Penryn, United Kingdom
| | - Thomas Sewell
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Matthew Fisher
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Rachael E Antwis
- School of Science, Engineering and Environment, University of Salford, Salford, United Kingdom
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27
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Kruger A. Functional Redundancy of Batrachochytrium dendrobatidis Inhibition in Bacterial Communities Isolated from Lithobates clamitans Skin. MICROBIAL ECOLOGY 2020; 79:231-240. [PMID: 31165187 DOI: 10.1007/s00248-019-01387-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/29/2019] [Indexed: 06/09/2023]
Abstract
The cutaneous microbial community can influence the health of amphibians exposed to Batrachochytrium dendrobatidis (Bd), a fungal pathogen that has contributed to recent amphibian declines. Resistance to Bd in amphibian populations is correlated with the presence of anti-Bd cutaneous microbes, which confer disease resistance by inhibiting Bd growth. I aimed to determine if green frogs (Lithobates clamitans), an abundant and widely distributed species in New Jersey, harbored bacteria that inhibit Bd and whether the presence and identity of these microbes varied among sites. I used in vitro challenge assays to determine if bacteria isolated from green frog skin could inhibit or enhance the growth of Bd. I found that green frogs at all sites harbored anti-Bd bacteria. However, there were differences in Bd inhibition capabilities among bacterial isolates identified as the same operational taxonomic unit (OTU), lending support to the idea that phylogenetic relatedness does not always predict Bd inhibition status. Additionally, anti-Bd bacterial richness did not vary by site, but the composition of anti-Bd bacterial taxa was distinct at each site. This suggests that there is functional redundancy of Bd inhibition across unique communities of anti-Bd symbionts found on frogs at different sites. These findings highlight the need to better elucidate the structure-function relationship of microbiomes and their role in disease resistance.
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Affiliation(s)
- Ariel Kruger
- Graduate Program in Ecology and Evolution, Department of Ecology, Evolution, and Natural Resources, Rutgers, The State University of New Jersey, 14 College Farm Road, New Brunswick, NJ, 08901, USA.
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28
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Harrison XA, Price SJ, Hopkins K, Leung WTM, Sergeant C, Garner TWJ. Diversity-Stability Dynamics of the Amphibian Skin Microbiome and Susceptibility to a Lethal Viral Pathogen. Front Microbiol 2019; 10:2883. [PMID: 31956320 PMCID: PMC6951417 DOI: 10.3389/fmicb.2019.02883] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 11/29/2019] [Indexed: 12/20/2022] Open
Abstract
Variation among animals in their host-associated microbial communities is increasingly recognized as a key determinant of important life history traits including growth, metabolism, and resistance to disease. Quantitative estimates of the factors shaping the stability of host microbiomes over time at the individual level in non-model organisms are scarce. Addressing this gap in our knowledge is important, as variation among individuals in microbiome stability may represent temporal gain or loss of key microbial species and functions linked to host health and/or fitness. Here we use controlled experiments to investigate how both heterogeneity in microbial species richness of the environment and exposure to the emerging pathogen Ranavirus influence the structure and temporal dynamics of the skin microbiome in a vertebrate host, the European common frog (Rana temporaria). Our evidence suggests that altering the bacterial species richness of the environment drives divergent temporal microbiome dynamics of the amphibian skin. Exposure to ranavirus effects changes in skin microbiome structure irrespective of total microbial diversity, but individuals with higher pre-exposure skin microbiome diversity appeared to exhibit higher survival. Higher diversity skin microbiomes also appear less stable over time compared to lower diversity microbiomes, but stability of the 100 most abundant ("core") community members was similar irrespective of microbiome richness. Our study highlights the importance of extrinsic factors in determining the stability of host microbiomes over time, which may in turn have important consequences for the stability of host-microbe interactions and microbiome-fitness correlations.
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Affiliation(s)
- Xavier A Harrison
- Institute of Zoology, Zoological Society of London, London, United Kingdom.,Centre for Ecology and Conservation, University of Exeter, Exeter, United Kingdom
| | - Stephen J Price
- Institute of Zoology, Zoological Society of London, London, United Kingdom.,UCL Genetics Institute, University College London, London, United Kingdom
| | - Kevin Hopkins
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - William T M Leung
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - Chris Sergeant
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - Trenton W J Garner
- Institute of Zoology, Zoological Society of London, London, United Kingdom
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29
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30
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Jiménez RR, Alvarado G, Estrella J, Sommer S. Moving Beyond the Host: Unraveling the Skin Microbiome of Endangered Costa Rican Amphibians. Front Microbiol 2019; 10:2060. [PMID: 31572313 PMCID: PMC6751270 DOI: 10.3389/fmicb.2019.02060] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 08/21/2019] [Indexed: 01/12/2023] Open
Abstract
Some neotropical amphibians, including a few species in Costa Rica, were presumed to be "extinct" after dramatic population declines in the late 1980s but have been rediscovered in isolated populations. Such populations seem to have evolved a resistance/tolerance to Batrachochytrium dendrobatidis (Bd), a fungal pathogen that causes a deadly skin disease and is considered one of the main drivers of worldwide amphibian declines. The skin microbiome is an important component of the host's innate immune system and is associated with Bd-resistance. However, the way that the bacterial diversity of the skin microbiome confers protection against Bd in surviving species remains unclear. We studied variation in the skin microbiome and the prevalence of putatively anti-Bd bacterial taxa in four co-habiting species in the highlands of the Juan Castro Blanco National Park in Costa Rica using 16S rRNA amplicon sequencing. Lithobates vibicarius, Craugastor escoces, and Isthmohyla rivularis have recently been rediscovered, whereas Isthmohyla pseudopuma has suffered population fluctuations but has never disappeared. To investigate the life stage at which the protective skin microbiome is shaped and when shifts occur in the diversity of putatively anti-Bd bacteria, we studied the skin microbiome of tadpoles, juveniles and adults of L. vibicarius. We show that the skin bacterial composition of sympatric species and hosts with distinct Bd-infection statuses differs at the phyla, family, and genus level. We detected 94 amplicon sequence variants (ASVs) with putative anti-Bd activity pertaining to distinct bacterial taxa, e.g., Pseudomonas spp., Acinetobacter johnsonii, and Stenotrophomonas maltophilia. Bd-uninfected L. vibicarius harbored 79% more putatively anti-Bd ASVs than Bd-infected individuals. Although microbiome composition and structure differed across life stages, the diversity of putative anti-Bd bacteria was similar between pre- and post-metamorphic stages of L. vibicarius. Despite low sample size, our results support the idea that the skin microbiome is dynamic and protects against ongoing Bd presence in endangered species persisting after their presumed extinction. Our study serves as a baseline to understand the microbial patterns in species of high conservation value. Identification of microbial signatures linked to variation in disease susceptibility might, therefore, inform mitigation strategies for combating the global decline of amphibians.
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Affiliation(s)
- Randall R. Jiménez
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany
| | - Gilbert Alvarado
- Laboratory of Comparative Wildlife Pathology, School of Veterinary Medicine and Animal Sciences, University of São Paulo, São Paulo, Brazil
- Laboratory of Experimental and Comparative Pathology (LAPECOM), Biology School, University of Costa Rica, San José, Costa Rica
| | - Josimar Estrella
- Laboratory of Experimental and Comparative Pathology (LAPECOM), Biology School, University of Costa Rica, San José, Costa Rica
| | - Simone Sommer
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany
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31
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Bates KA, Shelton JMG, Mercier VL, Hopkins KP, Harrison XA, Petrovan SO, Fisher MC. Captivity and Infection by the Fungal Pathogen Batrachochytrium salamandrivorans Perturb the Amphibian Skin Microbiome. Front Microbiol 2019; 10:1834. [PMID: 31507541 PMCID: PMC6716147 DOI: 10.3389/fmicb.2019.01834] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 07/25/2019] [Indexed: 12/13/2022] Open
Abstract
The emerging fungal pathogen, Batrachochytrium salamandrivorans (Bsal) is responsible for the catastrophic decline of European salamanders and poses a threat to amphibians globally. The amphibian skin microbiome can influence disease outcome for several host-pathogen systems, yet little is known of its role in Bsal infection. In addition, many experimental in-vivo amphibian disease studies to date have relied on specimens that have been kept in captivity for long periods without considering the influence of environment on the microbiome and how this may impact the host response to pathogen exposure. We characterized the impact of captivity and exposure to Bsal on the skin bacterial and fungal communities of two co-occurring European newt species, the smooth newt, Lissotriton vulgaris and the great-crested newt, Triturus cristatus. We show that captivity led to significant losses in bacterial and fungal diversity of amphibian skin, which may be indicative of a decline in microbe-mediated protection. We further demonstrate that in both L. vulgaris and T. cristatus, Bsal infection was associated with changes in the composition of skin bacterial communities with possible negative consequences to host health. Our findings advance current understanding of the role of host-associated microbiota in Bsal infection and highlight important considerations for ex-situ amphibian conservation programmes.
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Affiliation(s)
- Kieran A Bates
- Department of Zoology, University of Oxford, Oxford, United Kingdom.,Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom.,Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - Jennifer M G Shelton
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Victoria L Mercier
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Kevin P Hopkins
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - Xavier A Harrison
- Institute of Zoology, Zoological Society of London, London, United Kingdom.,College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Silviu O Petrovan
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom.,Froglife, Peterborough, United Kingdom
| | - Matthew C Fisher
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
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32
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Ellison S, Rovito S, Parra-Olea G, Vásquez-Almazán C, Flechas SV, Bi K, Vredenburg VT. The Influence of Habitat and Phylogeny on the Skin Microbiome of Amphibians in Guatemala and Mexico. MICROBIAL ECOLOGY 2019; 78:257-267. [PMID: 30467714 DOI: 10.1007/s00248-018-1288-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 11/06/2018] [Indexed: 06/09/2023]
Abstract
Microbial symbionts are increasingly recognized as playing a critical role in organismal health across a wide range of hosts. Amphibians are unique hosts in that their skin helps to regulate the exchange of water, ions, and gases, and it plays an active role in defense against pathogens through the synthesis of anti-microbial peptides. The microbiome of amphibian skin includes a diverse community of bacteria known to defend against pathogens, including the global pandemic lineage of Batrachochytrium dendrobatidis associated with mass amphibian die-offs. The relative influence of host phylogeny and environment in determining the composition of the amphibian skin microbiome remains poorly understood. We collected skin swabs from montane amphibians in Mexico and Guatemala, focusing on two genera of plethodontid salamanders and one genus of frogs. We used high throughput sequencing to characterize the skin bacterial microbiome and tested the impact of phylogeny and habitat on bacterial diversity. Our results show that phylogenetic history strongly influences the diversity and community structure of the total bacterial microbiome at higher taxonomic levels (between orders), but on lower scales (within genera and species), the effect of habitat predominates. These results add to a growing consensus that habitat exerts a strong effect on microbiome structure and composition, particularly at shallow phylogenetic scales.
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Affiliation(s)
- Silas Ellison
- Department of Biology, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA, 94132, USA
| | - Sean Rovito
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, 94720, USA.
- Unidad de Genómica Avanzada (Langebio), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Km 9.6 Libramiento Norte Carretera Irapuato-León, 36824, Irapuato, Guanajuato, Mexico.
| | - Gabriela Parra-Olea
- Departamento de Zoología, Insituto de Biología, Universidad Nacional Autónoma de México, CP04510, México, DF, Mexico
| | - Carlos Vásquez-Almazán
- Museo de Historia Natural y Escuela de Biología, Universidad de San Carlos, Guatemala, Guatemala
| | - Sandra V Flechas
- Department of Biological Sciences, Universidad de los Andes, AA 4976, Bogotá, Colombia
- Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Bogotá, Colombia
| | - Ke Bi
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, 94720, USA
- Computational Genomics Resource Laboratory, California Institute for Quantitative Biosciences University of California, Berkeley, CA, 94720, USA
| | - Vance T Vredenburg
- Department of Biology, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA, 94132, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, 94720, USA
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33
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Muletz-Wolz CR, Fleischer RC, Lips KR. Fungal disease and temperature alter skin microbiome structure in an experimental salamander system. Mol Ecol 2019; 28:2917-2931. [PMID: 31066947 DOI: 10.1111/mec.15122] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 03/27/2019] [Accepted: 04/25/2019] [Indexed: 12/29/2022]
Abstract
Pathogens compete with host microbiomes for space and resources. Their shared environment impacts pathogen-microbiome-host interactions, which can lead to variation in disease outcome. The skin microbiome of red-backed salamanders (Plethodon cinereus) can reduce infection by the pathogen Batrachochytrium dendrobatidis (Bd) at moderate infection loads, with high species richness and high abundance of competitors as putative mechanisms. However, it is unclear if the skin microbiome can reduce epizootic Bd loads across temperatures. We conducted a laboratory experiment to quantify skin microbiome and host responses (P. cinereus: n = 87) to Bd at mimicked epizootic loads across temperatures (13, 17 and 21°C). We quantified skin microbiomes using 16S rRNA gene metabarcoding and identified operational taxonomic units (OTUs) taxonomically similar to culturable bacteria known to kill Bd (anti-Bd OTUs). Prior to pathogen exposure, temperature changed the microbiome (OTU richness decreased by 12% and the abundance of anti-Bd OTUs increased by 18% per degree increase in temperature), but these changes were not predictive of disease outcome. After exposure, Bd changed the microbiome (OTU richness decreased by 0.1% and the abundance of anti-Bd OTUs increased by 0.2% per 1% increase in Bd load) and caused high host mortality across temperatures (35/45: 78%). Temperature indirectly impacted microbiome change and mortality through its direct effect on pathogen load. We did not find support for the microbiome impacting Bd load or host survival. Our research reveals complex host, pathogen, microbiome and environmental interactions to demonstrate that during epizootic events the microbiome will be unlikely to reduce pathogen invasion, even for putatively Bd-resistant species.
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Affiliation(s)
- Carly R Muletz-Wolz
- Department of Biology, University of Maryland, College Park, Maryland.,Center for Conservation Genomics, Smithsonian National Zoological Park and Conservation Biology Institute, Washington, District of Columbia
| | - Robert C Fleischer
- Center for Conservation Genomics, Smithsonian National Zoological Park and Conservation Biology Institute, Washington, District of Columbia
| | - Karen R Lips
- Department of Biology, University of Maryland, College Park, Maryland
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34
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Frenken T, Agha R, Schmeller DS, van West P, Wolinska J. Biological Concepts for the Control of Aquatic Zoosporic Diseases. Trends Parasitol 2019; 35:571-582. [PMID: 31076352 DOI: 10.1016/j.pt.2019.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/04/2019] [Accepted: 04/06/2019] [Indexed: 12/26/2022]
Abstract
Aquatic zoosporic diseases are threatening global biodiversity and ecosystem services, as well as economic activities. Current means of controlling zoosporic diseases are restricted primarily to chemical treatments, which are usually harmful or likely to be ineffective in the long term. Furthermore, some of these chemicals have been banned due to adverse effects. As a result, there is a need for alternative methods with minimal side-effects on the ecosystem or environment. Here, we integrate existing knowledge of three poorly interconnected areas of disease research - amphibian conservation, aquaculture, and plankton ecology - and arrange it into seven biological concepts to control zoosporic diseases. These strategies may be less harmful and more sustainable than chemical approaches. However, more research is needed before safe application is possible.
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Affiliation(s)
- Thijs Frenken
- Department of Ecosystem Research, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany.
| | - Ramsy Agha
- Department of Ecosystem Research, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
| | - Dirk S Schmeller
- ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Pieter van West
- Aberdeen Oomycete Laboratory, College of Life Sciences and Medicine, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Justyna Wolinska
- Department of Ecosystem Research, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany; Institute of Biology, Freie Universität Berlin, Berlin, Germany
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35
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Trevelline BK, Fontaine SS, Hartup BK, Kohl KD. Conservation biology needs a microbial renaissance: a call for the consideration of host-associated microbiota in wildlife management practices. Proc Biol Sci 2019; 286:20182448. [PMID: 30963956 PMCID: PMC6364583 DOI: 10.1098/rspb.2018.2448] [Citation(s) in RCA: 191] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/03/2019] [Indexed: 12/14/2022] Open
Abstract
The central aim of conservation biology is to understand and mitigate the effects of human activities on biodiversity. To successfully achieve this objective, researchers must take an interdisciplinary approach that fully considers the effects, both direct and indirect, of anthropogenic disturbances on wildlife physiology and health. A recent surge in research has revealed that host-associated microbiota-the archaeal, bacterial, fungal and viral communities residing on and inside organisms-profoundly influence animal health, and that these microbial communities can be drastically altered by anthropogenic activities. Therefore, conservation practitioners should consider the disruption of host-associated microbial diversity as a serious threat to wildlife populations. Despite the tremendous potential for microbiome research to improve conservation outcomes, few efforts have been made to truly integrate these fields. In this review, we call for the microbial renaissance of conservation biology, where biodiversity of host-associated microbiota is recognized as an essential component of wildlife management practices. Using evidence from the existing literature, we will examine the known effects of anthropogenic activities on the diversity of host-associated microbial communities and integrate approaches for maintaining microbial diversity to successfully achieve conservation objectives.
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Affiliation(s)
- Brian K. Trevelline
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Samantha S. Fontaine
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Barry K. Hartup
- Department of Conservation Medicine, International Crane Foundation, Baraboo, WI, USA
- School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA
| | - Kevin D. Kohl
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
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Bletz MC, Kelly M, Sabino-Pinto J, Bales E, Van Praet S, Bert W, Boyen F, Vences M, Steinfartz S, Pasmans F, Martel A. Disruption of skin microbiota contributes to salamander disease. Proc Biol Sci 2018; 285:rspb.2018.0758. [PMID: 30135150 DOI: 10.1098/rspb.2018.0758] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/27/2018] [Indexed: 12/15/2022] Open
Abstract
Escalating occurrences of emerging infectious diseases underscore the importance of understanding microbiome-pathogen interactions. The amphibian cutaneous microbiome is widely studied for its potential to mitigate disease-mediated amphibian declines. Other microbial interactions in this system, however, have been largely neglected in the context of disease outbreaks. European fire salamanders have suffered dramatic population crashes as a result of the newly emerged Batrachochytrium salamandrivorans (Bsal). In this paper, we investigate microbial interactions on multiple fronts within this system. We show that wild, healthy fire salamanders maintain complex skin microbiotas containing Bsal-inhibitory members, but these community are present at a remarkably low abundance. Through experimentation, we show that increasing bacterial densities of Bsal-inhibiting bacteria via daily addition slowed disease progression in fire salamanders. Additionally, we find that experimental-Bsal infection elicited subtle changes in the skin microbiome, with selected opportunistic bacteria increasing in relative abundance resulting in septicemic events that coincide with extensive destruction of the epidermis. These results suggest that fire salamander skin, in natural settings, maintains bacterial communities at numbers too low to confer sufficient protection against Bsal, and, in fact, the native skin microbiota can constitute a source of opportunistic bacterial pathogens that contribute to pathogenesis. By shedding light on the complex interaction between the microbiome and a lethal pathogen, these data put the interplay between skin microbiomes and a wildlife disease into a new perspective.
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Affiliation(s)
- Molly C Bletz
- Department of Biology, University of Massachusetts Boston, 100 Morrissey Blvd., Boston, MA 02125, USA .,Zoological Institute, Technische Universität Braunschweig, Braunschweig 38106, Germany
| | - Moira Kelly
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
| | - Joana Sabino-Pinto
- Zoological Institute, Technische Universität Braunschweig, Braunschweig 38106, Germany
| | - Emma Bales
- Zoological Institute, Technische Universität Braunschweig, Braunschweig 38106, Germany
| | - Sarah Van Praet
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
| | - Wim Bert
- Department of Biology, Nematology Research Unit, Faculty of Science, Ghent University, 9000 Ghent, Belgium
| | - Filip Boyen
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
| | - Miguel Vences
- Zoological Institute, Technische Universität Braunschweig, Braunschweig 38106, Germany
| | - Sebastian Steinfartz
- Zoological Institute, Technische Universität Braunschweig, Braunschweig 38106, Germany
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
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37
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Antwis RE, Harrison XA. Probiotic consortia are not uniformly effective against different amphibian chytrid pathogen isolates. Mol Ecol 2018; 27:577-589. [PMID: 29218845 DOI: 10.1111/mec.14456] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 11/27/2017] [Indexed: 12/20/2022]
Abstract
Symbiotic bacterial communities can protect their hosts from infection by pathogens. Treatment of wild individuals with protective bacteria (probiotics) isolated from hosts can combat the spread of emerging infectious diseases. However, it is unclear whether candidate probiotic bacteria can offer consistent protection across multiple isolates of globally distributed pathogens. Here, we use the lethal amphibian fungal pathogen Batrachochytrium dendrobatidis to investigate whether probiotic richness (number of bacteria) or genetic distance among consortia members influences broad-scale in vitro inhibitory capabilities of probiotics across multiple isolates of the pathogen. We show that inhibition of multiple pathogen isolates by individual bacteria is rare, with no systematic pattern among bacterial genera in ability to inhibit multiple B. dendrobatidis isolates. Bacterial consortia can offer stronger protection against B. dendrobatidis compared to single strains, and this tended to be more pronounced for consortia containing multiple genera compared with those consisting of bacteria from a single genus (i.e., with lower genetic distance), but critically, this effect was not uniform across all B. dendrobatidis isolates. These novel insights have important implications for the effective design of bacterial probiotics to mitigate emerging infectious diseases.
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Affiliation(s)
- Rachael E Antwis
- School of Environment and Life Sciences, University of Salford, Salford, UK.,Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
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38
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Antwis RE, Weldon C. Amphibian skin defences show variation in ability to inhibit growth of Batrachochytrium dendrobatidis isolates from the Global Panzootic Lineage. MICROBIOLOGY-SGM 2017; 163:1835-1838. [PMID: 29095686 DOI: 10.1099/mic.0.000570] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The fungal pathogen Batrachochytrium dendrobatidis has caused declines and extinctions in hundreds of amphibian species across the world. Virulence varies among and within lineages; the Global Panzootic Lineage (GPL) is the most pathogenic, although there is also variation in lethality among GPL isolates. Amphibians have a number of defences against pathogens, and skin products including the microbiota and host peptides have considerable influence over disease progression. Here we demonstrate that the collective skin products (the mucosome) of two amphibian species show significant variation in their ability to inhibit different globally distributed isolates of GPL. This may in part explain the variation in disease susceptibility of hosts to different strains of B. dendrobatidis. More work is required to identify particular traits associated with mucosomes that confer broad-spectrum inhibition across GPL in order to facilitate the development of prophylaxis and/or treatments for chytridiomycosis in situ.
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Affiliation(s)
- Rachael Ellen Antwis
- School of Environment and Life Sciences, University of Salford, Salford, UK
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
| | - Ché Weldon
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
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