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1.
Nat Commun ; 11(1): 5393, 2020 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-33106491

RESUMO

Wildlife diseases are contributing to the current Earth's sixth mass extinction; one disease, chytridiomycosis, has caused mass amphibian die-offs. While global spread of a hypervirulent lineage of the fungus Batrachochytrium dendrobatidis (BdGPL) causes unprecedented loss of vertebrate diversity by decimating amphibian populations, its impact on amphibian communities is highly variable across regions. Here, we combine field data with in vitro and in vivo trials that demonstrate the presence of a markedly diverse variety of low virulence isolates of BdGPL in northern European amphibian communities. Pre-exposure to some of these low virulence isolates protects against disease following subsequent exposure to highly virulent BdGPL in midwife toads (Alytes obstetricans) and alters infection dynamics of its sister species B. salamandrivorans in newts (Triturus marmoratus), but not in salamanders (Salamandra salamandra). The key role of pathogen virulence in the complex host-pathogen-environment interaction supports efforts to limit pathogen pollution in a globalized world.


Assuntos
Anuros/microbiologia , Quitridiomicetos/patogenicidade , Micoses/veterinária , Salamandridae/microbiologia , Urodelos/microbiologia , Animais , Quitridiomicetos/classificação , Quitridiomicetos/fisiologia , Micoses/microbiologia , Virulência
2.
Parasitol Res ; 119(11): 3659-3673, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32960371

RESUMO

Alongside exotic reptiles, amphibians, such as toads, frogs, salamanders, and newts, are nowadays considered popular pets worldwide. As reported for other exotic pet animals, amphibians are known to harbor numerous gastrointestinal parasites. Nonetheless, very little data are available on captive amphibian parasitic diseases. In this study, we applied direct saline fecal smears (DSFS) to examine in total 161 stool samples from 41 different amphibian species belonging to the orders Anura and Caudata. In addition, carbolfuchsin-smear (CFS) staining (n = 74 samples) was used to detect amphibian Cryptosporidium oocysts. Also, complete dissections of deceased amphibians (n = 107) were performed to specify parasite infections and to address parasite-associated pathogenicity. Overall, examined amphibian fecal samples contained 12 different parasite taxa. The order Rhabditida with the species Rhabdias spp. and Strongyloides spp. were the most prevalent nematode species (19.3%), followed by flagellated protozoans (8.7%), Amphibiocapillaria spp./Neocapillaria spp. (7.5%), Oswaldocruzia spp. (4.3%), Blastocystis spp. (3.1%), Cosmocerca spp. (3.1%), oxyurids (Pharyngonoidae) (3.1%), spirurids (1.2%), un-sporulated coccidian oocysts (0.6%), Tritrichomonas spp. (0.6%), Karotomorpha spp. (0.6%), and Cryptosporidium spp. (0.6%). One CFS-stained fecal sample (1.4%) was positive for Cryptosporidium oocysts. Within dissected amphibians, 31 (48.4%) of the anurans and 11 (26.2%) of the salamanders were infected with gastrointestinal parasites. One cutaneous Pseudocapillaroides xenopi infection was diagnosed in an adult African clawed frog (Xenopus laevis). Etiologically, 17 (15.9%) of them died due to severe parasitic and/or bacterial infections (e.g., Chryseobacterium indologenes, Citrobacter freudii, Sphingobacterium multivorum, Klebsiella pneumoniae). High prevalence and pathological findings of several clinical amphibian parasitoses call for more detailed investigation on gastrointestinal parasite-derived molecular mechanisms associated with detrimental lesions or even death.


Assuntos
Animais Exóticos , Animais de Zoológico/parasitologia , Anuros/parasitologia , Enteropatias Parasitárias/veterinária , Urodelos/parasitologia , Animais , Anuros/microbiologia , Blastocystis/isolamento & purificação , Chryseobacterium/isolamento & purificação , Criptosporidiose/parasitologia , Cryptosporidium/isolamento & purificação , Fezes/parasitologia , Feminino , Enteropatias Parasitárias/parasitologia , Nematoides/isolamento & purificação , Oocistos , Sphingobacterium , Strongyloides/isolamento & purificação , Urodelos/microbiologia
3.
PLoS One ; 15(9): e0235370, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32915779

RESUMO

Controlled experiments are one approach to understanding the pathogenicity of etiologic agents to susceptible hosts. The recently discovered fungal pathogen, Batrachochytrium salamandrivorans (Bsal), has resulted in a surge of experimental investigations because of its potential to impact global salamander biodiversity. However, variation in experimental methodologies could thwart knowledge advancement by introducing confounding factors that make comparisons difficult among studies. Thus, our objective was to evaluate if variation in experimental methods changed inferences made on the pathogenicity of Bsal. We tested whether passage duration of Bsal culture, exposure method of the host to Bsal (water bath vs. skin inoculation), Bsal culturing method (liquid vs. plated), host husbandry conditions (aquatic vs. terrestrial), and skin swabbing frequency influenced diseased-induced mortality in a susceptible host species, the eastern newt (Notophthalmus viridescens). We found that disease-induced mortality was faster for eastern newts when exposed to a low passage isolate, when newts were housed in terrestrial environments, and if exposure to zoospores occurred via water bath. We did not detect differences in disease-induced mortality between culturing methods or swabbing frequencies. Our results illustrate the need to standardize methods among Bsal experiments. We provide suggestions for future Bsal experiments in the context of hypothesis testing and discuss the ecological implications of our results.


Assuntos
Quitridiomicetos/patogenicidade , Micoses/veterinária , Urodelos/microbiologia , Animais , Técnicas de Cultura de Células , Quitridiomicetos/isolamento & purificação , Quitridiomicetos/fisiologia , Micoses/microbiologia , Micoses/patologia , Pele/microbiologia , Pele/patologia , Coloração e Rotulagem , Urodelos/fisiologia
4.
Microb Ecol ; 79(4): 985-997, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31802185

RESUMO

A multicellular host and its microbial communities are recognized as a metaorganism-a composite unit of evolution. Microbial communities have a variety of positive and negative effects on the host life history, ecology, and evolution. This study used high-throughput amplicon sequencing to characterize the complete skin and gut microbial communities, including both bacteria and fungi, of a terrestrial salamander, Plethodon glutinosus (Family Plethodontidae). We assessed salamander populations, representing nine mitochondrial haplotypes ('clades'), for differences in microbial assemblages across 13 geographic locations in the Southeastern United States. We hypothesized that microbial assemblages were structured by both host factors and geographic distance. We found a strong correlation between all microbial assemblages at close geographic distances, whereas, as spatial distance increases, the patterns became increasingly discriminate. Network analyses revealed that gut-bacterial communities have the highest degree of connectedness across geographic space. Host salamander clade was explanatory of skin-bacterial and gut-fungal assemblages but not gut-bacterial assemblages, unless the latter were analyzed within a phylogenetic context. We also inferred the function of gut-fungal assemblages to understand how an understudied component of the gut microbiome may influence salamander life history. We concluded that dispersal limitation may in part describe patterns in microbial assemblages across space and also that the salamander host may select for skin and gut communities that are maintained over time in closely related salamander populations.


Assuntos
Fenômenos Fisiológicos Bacterianos , Fungos/fisiologia , Trato Gastrointestinal/microbiologia , Microbiota , Pele/microbiologia , Urodelos/microbiologia , Distribuição Animal , Animais , Bactérias/isolamento & purificação , Fungos/isolamento & purificação , Microbioma Gastrointestinal , Micobioma , Sudeste dos Estados Unidos , Análise Espacial , Tennessee
5.
Mol Biol Rep ; 46(5): 5143-5154, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31364018

RESUMO

Increasing attention has been attracted to host microbiota, due to their vital impact on host health. Little is known about the microbiota of the Chinese giant salamander (Andrias davidianus), in spite of the high economic and scientific value of this endangered species. This study was designed to characterise and compare the gut and lung prokaryotic communities of the Chinese giant salamander by high-throughput sequencing. Our study showed that the giant salamander had a lung prokaryotic community that clustered separately from its intestinal microbiota. Statistical analysis (LEfSe) revealed that the bacterial populations were dominated by Geobacter, Sulfurimonas, and Dechloromonas from Proteobacteria phylum, and Corynebacterium from Actinobacteria phylum in the lung, while Parabacteroides, Bacteroides, and PW3 from Bacteroidetes phylum, and Oscillospira from Firmicutes phylum were predominant in the intestine. A particularly innovative finding was the fairly high abundance of Archaea, especially methanogenic Euryarchaeota. The gut dominant Archaea were Methanocorpusculum and Thermoplasmata vadinCA11, while Methanosaeta and Methanoculleus were the main Archaea in the lung. PICRUSt analysis revealed differentiated functional profiles between the intestinal miacrobiota and the lung microbiota. Specially, some microbial metabolic functions were significantly more active in the intestinal microbiota, while the functional genes involved in infectious diseases were much richer in the lung microbiota. This study characterized the prokaryotic microbial community profiles in the gut and lung of the Chinese giant salamander, providing foundational support for future study seeking to understand microbiota of the giant salamander and the role of its microbiota on infectious diseases.


Assuntos
Archaea/classificação , Bactérias/classificação , Trato Gastrointestinal/microbiologia , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Pulmão/microbiologia , Urodelos/microbiologia , Animais , Archaea/genética , Archaea/isolamento & purificação , Bactérias/genética , Bactérias/isolamento & purificação , DNA Arqueal/genética , DNA Bacteriano/genética , Microbioma Gastrointestinal , Especificidade de Órgãos , Filogenia , Análise de Sequência de DNA
6.
Emerg Infect Dis ; 25(7): 1416-1418, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31211934

RESUMO

The distribution of the chytrid fungus Batrachochytrium salamandrivorans continues to expand in Europe. During 2014-2018, we collected 1,135 samples from salamanders and newts in 6 countries in Europe. We identified 5 cases of B. salamandrivorans in a wild population in Spain but none in central Europe or the Balkan Peninsula.


Assuntos
Doenças dos Animais/microbiologia , Quitridiomicetos , Micoses/veterinária , Urodelos/microbiologia , Doenças dos Animais/diagnóstico , Animais , Quitridiomicetos/classificação , Quitridiomicetos/genética , Quitridiomicetos/isolamento & purificação , Reação em Cadeia da Polimerase
7.
Mol Ecol ; 28(11): 2917-2931, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31066947

RESUMO

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.


Assuntos
Microbiota , Micoses/microbiologia , Pele/microbiologia , Temperatura , Urodelos/microbiologia , Animais , Quitridiomicetos/fisiologia , Interações Hospedeiro-Patógeno , Funções Verossimilhança , Análise de Sobrevida
9.
Parasit Vectors ; 12(1): 108, 2019 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-30871588

RESUMO

BACKGROUND: Eurycea sosorum (Barton Springs salamander) and Eurycea nana (San Macros salamander) are listed as endangered and threatened species, respectively, by the U.S. Fish and Wildlife Service (USFWS) with habitats restricted to small regions near Austin, Texas, USA. The conservation efforts with the Eurycea salamanders at the captive breeding program in San Marcos Aquatic Resources Center (SMARC), a USFWS facility, have seen an unexpected and increased mortality rate over the past few years. The clinical signs of sick or dead salamanders included erythema, tail loss, asymmetric gills or brachial loss, rhabdomyolysis, kyphosis, and behavior changes, suggesting that an infectious disease might be the culprit. This study aimed to identify the cause of the infection, determine the taxonomic position of the pathogen, and investigate the potential reservoirs of the pathogen in the environment. RESULTS: Histopathological examination indicated microsporidian infection (microsporidiosis) in the sick and dead Eurycea salamanders that was later confirmed by PCR detection. We also determined the near full-length small subunit ribosomal RNA (SSU rRNA) gene from the microsporidian pathogen, which allowed us to determine its phylogenetic position, and to design primers for specific and sensitive detection of the pathogen. Phylogenetic analysis indicated that this pathogen was closely related to the insect parasites Vavraia spp. and the human opportunistic pathogen, Trachipleistophora hominis. This Vavraia-like microsporidium was present in dead salamanders at SMARC archived between 2011 and 2015 (positive rates ranging between 52.0-88.9% by PCR detection), as well as in some aquatic invertebrates at the facility (e.g. snails and small crustaceans). CONCLUSIONS: A Vavraia-like microsporidian was at least one of the major pathogens, if not solely, responsible for the sickness and mortality in the SMARC salamanders, and the pathogen had been present in the center for years. Environmental invertebrates likely served as a source and reservoir of the microsporidian pathogen. These observations provide new knowledge and a foundation for future conservation efforts for Eurycea salamanders including molecular surveys, monitoring of the pathogen, and discovery of effective treatments.


Assuntos
Microsporídios não Classificados/isolamento & purificação , Microsporidiose/microbiologia , Urodelos/microbiologia , Animais , Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Invertebrados , Microsporídios não Classificados/genética , Microsporidiose/diagnóstico , Microsporidiose/mortalidade , Filogenia , Estados Unidos
10.
PLoS One ; 14(2): e0211960, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30753218

RESUMO

The recent decline in populations of European salamanders caused by the chytrid fungus Batrachochytrium salamandrivorans (Bsal) has generated worldwide concern, as it is a major threat to amphibians. Evaluation of the areas most suitable for the establishment of Bsal combined with analysis of the distribution of salamander species could be used to generate and implement biosecurity measures and protect biodiversity at sites with high salamander diversity. In this study, we identified the areas most suitable for the establishment of Bsal in Mexico. Mexico has the second-highest salamander species diversity in the world; thus, we identified areas moderately to highly suitable for the establishment of Bsal with high salamander diversity as potential hotspots for surveillance. Central and Southern Mexico were identified as high-risk zones, with 13 hotspots where 30% of Mexican salamander species occur, including range-restricted species and endangered species. We propose that these hotspots should be thoroughly monitored for the presence of Bsal to prevent the spread of the pathogen if it is introduced to the country.


Assuntos
Quitridiomicetos/patogenicidade , Urodelos/crescimento & desenvolvimento , Distribuição Animal , Animais , Biodiversidade , Demografia , Espécies em Perigo de Extinção/estatística & dados numéricos , México , Vigilância da População , Urodelos/microbiologia
11.
Nat Ecol Evol ; 3(3): 381-389, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30778181

RESUMO

Animal-associated microbiomes are integral to host health, yet key biotic and abiotic factors that shape host-associated microbial communities at the global scale remain poorly understood. We investigated global patterns in amphibian skin bacterial communities, incorporating samples from 2,349 individuals representing 205 amphibian species across a broad biogeographic range. We analysed how biotic and abiotic factors correlate with skin microbial communities using multiple statistical approaches. Global amphibian skin bacterial richness was consistently correlated with temperature-associated factors. We found more diverse skin microbiomes in environments with colder winters and less stable thermal conditions compared with environments with warm winters and less annual temperature variation. We used bioinformatically predicted bacterial growth rates, dormancy genes and antibiotic synthesis genes, as well as inferred bacterial thermal growth optima to propose mechanistic hypotheses that may explain the observed patterns. We conclude that temporal and spatial characteristics of the host's macro-environment mediate microbial diversity.


Assuntos
Anuros/microbiologia , Clima , Microbiota , Urodelos/microbiologia , Animais , Bactérias/classificação , Fenômenos Fisiológicos Bacterianos , Pele/microbiologia
12.
FEMS Microbiol Ecol ; 95(3)2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30649314

RESUMO

The European cave salamander Proteus anguinus is a charismatic amphibian endemic to the concealed and inaccessible subterranean waters of the Dinaric Karst. Despite its exceptional conservation importance not much is known about its ecology and interactions with the groundwater microbiome. The cutaneous microbiota of amphibians is an important driver of metabolic capabilities and immunity, and thus a key factor in their wellbeing and survival. We used high-throughput 16S rRNA gene sequencing based on seven variable regions to examine the bacteriome of the skin of five distinct evolutionary lineages of P. anguinus and in their groundwater environment. The skin bacteriomes turned out to be strongly filtered subsamples of the environmental microbial community. The resident microbiota of the analyzed individuals was dominated by five bacterial taxa. Despite an indicated functional redundancy, the cutaneous bacteriome of P. anguinus presumably provides protection against invading microbes by occupying the niche, and thus could serve as an indicator of health status. Besides conservation implications for P. anguinus, our results provide a baseline for future studies on other endangered neotenic salamanders.


Assuntos
Cavernas/microbiologia , Microbiota , Urodelos/microbiologia , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Evolução Biológica , Água Subterrânea/microbiologia , RNA Ribossômico 16S/genética , Pele/microbiologia , Urodelos/classificação
13.
Microb Ecol ; 77(3): 782-793, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30209587

RESUMO

Variation in environmental conditions can result in disparate associations between hosts and microbial symbionts. As such, it is imperative to evaluate how environmental variables (e.g., habitat quality) can influence host-associated microbiome composition. Within wildlife conservation programs, captive conditions can negatively influence the establishment and maintenance of "wild-type" microbiotas within a host. Alternative microbial communities can result in the proliferation of disease among captive stock or upon reintroduction. Hellbenders (Cryptobranchus alleganiensis) are a threatened salamander for which extensive captive management is currently employed. Using metabarcoding, we characterized the skin microbiota of wild and captive hellbenders from two subspecies in the state of Missouri, the eastern (C. a. alleganiensis) and the Ozark hellbender (C. a. bishopi). Both subspecies in our study included wild adults and captive juveniles that were collected from the wild as eggs. Our objectives were to investigate differences in the skin microbial communities' richness/diversity, composition, and functional profiles of microbes between wild and captive individuals. Captive eastern hellbenders possessed richer communities than wild cohorts, whereas the opposite pattern was observed within the Ozark subspecies. We found significant microbial community structure between wild and captive populations of both subspecies. Microbiota structure translated into differences in the predicted metagenome of wild and captive individuals as well. As such, we can expect captive hellbenders to experience alternative microbial structure and function upon reintroduction into the wild. Our study provides a baseline for the effect of captivity on the skin microbial communities of hellbenders, and highlights the need to incorporate microbiota management in current captive-rearing programs.


Assuntos
Bactérias/isolamento & purificação , Microbiota , Pele/microbiologia , Urodelos/microbiologia , Animais , Bactérias/classificação , Bactérias/genética , Feminino , Masculino , Missouri , Filogenia , Urodelos/crescimento & desenvolvimento
14.
J Exp Biol ; 221(Pt 20)2018 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-30171093

RESUMO

Environmental temperature and gut microbial communities can both have profound impacts on the digestive performance of ectothermic vertebrates. Additionally, the diversity, composition and function of gut microbial communities themselves are influenced by temperature. It is typically assumed that the temperature-dependent nature of ectotherm digestive performance is due to factors such as host physiological changes and adaptation to local climatic conditions. However, it is also possible that temperature-induced alterations to gut microbiota may influence the relationship between temperature and digestion. To explore the connections between these three factors, we compared digestive performance and gut microbial community diversity and composition in red-backed salamanders housed at three experimental temperatures: 10, 15 and 20°C. We also investigated associations between specific bacterial taxa and temperature or salamander digestive performance. We found that salamander digestive performance was greatest at 15°C, while gut microbial diversity was reduced at 20°C. Further, gut microbial community composition differed among the three temperature treatments. The relative abundance of 25 bacterial genera was dependent on temperature, with high temperatures being associated with reductions in the relative abundance of disease-resistant bacteria and increases in pathogenic taxa. The relative abundance of four bacterial genera was correlated with salamander energy assimilation, two of which are known to digest chitin, a main component of the red-backed salamander diet. These findings suggest that gut microbiota may mediate the relationship between temperature and digestion in ectotherms. We discuss how global climate change may impact ectotherms by altering host-microbe interactions.


Assuntos
Digestão/fisiologia , Microbioma Gastrointestinal/fisiologia , Temperatura Alta , Urodelos/microbiologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Bactérias/classificação , Bactérias/isolamento & purificação , Bactérias/metabolismo , Urodelos/fisiologia
15.
PLoS One ; 13(7): e0199295, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30020936

RESUMO

Recently emerged fungal diseases, Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) are an increasing threat to amphibians worldwide. In Europe, the threat of Bsal to salamander populations is demonstrated by the rapid decline of fire salamander populations in Germany, the Netherlands and Belgium. Although most European urodelans are susceptible to infection in infection trials, recent evidence suggests marked interspecific differences in the course of infection, with potentially far reaching implications for salamander conservation. As a salamander's skin is the first line of defense against such pathogens, interspecific differences in innate immune function of the skin may explain differential susceptibility. Here we investigate if compounds present on a salamander's skin can kill Bsal spores and if there is variation among species. We used a non-invasive assay to compare killing ability of salamander mucosomes of four different species (captive and wild Salamandra salamandra and captive Ichtyosaura alpestris, Cynops pyrrhogaster and Lissotriton helveticus) by exposing Bsal zoospores to salamander mucosomes and determining spore survival. In all samples, zoospores were killed when exposed to mucosomes. Moreover, we saw a significant variation in this Bsal killing ability of mucosomes between different salamander host species. Our results indicate that mucosomes of salamanders might provide crucial skin protection against Bsal, and could explain why some species are more susceptible than others. This study represents a step towards better understanding host species variation in innate immune function and disease susceptibility in amphibians.


Assuntos
Quitridiomicetos/patogenicidade , Micoses/microbiologia , Pele/química , Urodelos/microbiologia , Animais , Bélgica/epidemiologia , Suscetibilidade a Doenças/imunologia , Suscetibilidade a Doenças/microbiologia , Alemanha/epidemiologia , Micoses/epidemiologia , Micoses/imunologia , Países Baixos/epidemiologia , Pele/imunologia , Pele/microbiologia , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/patogenicidade , Urodelos/imunologia
16.
Dis Aquat Organ ; 129(1): 15-30, 2018 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-29916389

RESUMO

Proteus anguinus is a neotenic cave amphibian endemic to the Dinaric Karst and represents a symbol of Slovenian natural heritage. It is classified as 'Vulnerable' by the International Union for Conservation of Nature (IUCN) and is one of the EU priority species in need of strict protection. Due to inaccessibility of its natural underground habitat, scientific studies have been primarily conducted on Proteus in captivity where amphibians may be particularly susceptible to opportunistic microbial infections. In this case report, we present the results of an analysis of an individual that had been kept in captivity for 6 yr and then developed clinical symptoms, including ulcers, suggesting opportunistic microbial infection. Pigmented fungal hyphae and yeast-like cells were present in the dermis and in almost all other sampled tissues. Sampling of the ulcer allowed the isolation of a diverse array of bacterial and fungal species. We identified the water-borne, polymorphic black yeast Exophiala salmonis, an opportunistic pathogen of fish, as the cause of the primary infection. This is the first report on a fungal infection of Proteus and on cave salamanders in general.


Assuntos
Fungos/isolamento & purificação , Micoses/veterinária , Urodelos/microbiologia , Animais , Bactérias/classificação , Bactérias/isolamento & purificação , Fungos/classificação , Abrigo para Animais , Micoses/microbiologia , Microbiologia da Água
17.
Sci Rep ; 8(1): 3800, 2018 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-29491409

RESUMO

Lack of disease spill-over between adjacent populations has been associated with habitat fragmentation and the absence of population connectivity. We here present a case which describes the absence of the spill-over of the chytrid fungus Batrachochytrium salamandrivorans (Bsal) between two connected subpopulations of fire salamanders (Salamandra salamandra). Based on neutrally evolving microsatellite loci, both subpopulations were shown to form a single genetic cluster, suggesting a shared origin and/or recent gene flow. Alpine newts (Ichthyosaura alpestris) and fire salamanders were found in the landscape matrix between the two sites, which are also connected by a stream and separated by no obvious physical barriers. Performing a laboratory trial using alpine newts, we confirmed that Bsal is unable to disperse autonomously. Vector-mediated dispersal may have been impeded by a combination of sub-optimal connectivity, limited dispersal ability of infected hosts and a lack of suitable dispersers following the rapid, Bsal-driven collapse of susceptible hosts at the source site. Although the exact cause remains unclear, the aggregate evidence suggests that Bsal may be a poorer disperser than previously hypothesized. The lack of Bsal dispersal between neighbouring salamander populations opens perspectives for disease management and stresses the necessity of implementing biosecurity measures preventing human-mediated spread.


Assuntos
Quitridiomicetos/fisiologia , Refúgio de Vida Selvagem , Urodelos/microbiologia , Animais , Família Multigênica/genética , Urodelos/genética
18.
Electron. j. biotechnol ; 32: 47-54, Mar. 2018. tab, ilus, graf
Artigo em Inglês | LILACS | ID: biblio-1022746

RESUMO

Background: Cathepsin C (CTSC) (dipeptidyl peptidase I, DPPI), is a member of the papain superfamily of cysteine proteases and involves in a variety of host reactions. However, the information of CTST in Chinese giant salamander (Andrias davidianus), an amphibian species with important evolutionary position and economic values, remained unclear. Results: The full-length salamander CTSC cDNA contained a 96 bp of 5'-UTR, a 1392 bp of ORF encoding 463 amino acids, and a 95 bp of 3'-UTR. The salamander CTSC possessed several sequence features similar to other reported CTSCs such as a signal peptide, a propeptide and a mature peptide. The active site triad of Cys, His and Asn were also found existing in salamander CTSC. Salamander CTSC mRNA was constitutively expressed in all the examined tissues with significantly variant expression level. The highest expression of CTSC was in intestine, followed with stomach, spleen, lung and brain. Following Aeromonas hydrophila infection for 12 h, salamander CTSC was significantly up-regulated in several tissues including lung, spleen, brain, kidney, heart, stomach and skin. Conclusion: CTSC plays roles in the immune response to bacterial infection, which provided valuable information for further studying the functions of CTSC in salamander.


Assuntos
Animais , Urodelos/genética , Urodelos/imunologia , Infecções por Bactérias Gram-Negativas/veterinária , Catepsina C/imunologia , Urodelos/microbiologia , Infecções por Bactérias Gram-Negativas/imunologia , Clonagem Molecular , Aeromonas hydrophila/fisiologia , Análise de Sequência , DNA Complementar , Catepsina C/genética , Catepsina C/metabolismo , Transcrição Reversa , Imunidade Inata/genética
19.
Mol Ecol ; 27(8): 1915-1929, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29411437

RESUMO

The complex association between hosts and microbial symbionts requires the implementation of multiple approaches to evaluate variation in host physiology. Within amphibians, heterogeneity in immunogenetic traits and cutaneous microbiota is associated with variation in disease resistance. Ozark (Cryptobranchus alleganiensis bishopi) and eastern hellbenders (C. a. alleganiensis) provide a model system to assess variation in host traits and microbial communities. Ozark hellbenders have experienced declines throughout their range, are federally endangered and experience wound retardation that is absent in the eastern subspecies. Previous microbial investigations indicate differentiation in the composition of the skin microbiota of both hellbender subspecies, but it is not clear whether these patterns are concurrent with diversity in the major histocompatibility complex (MHC) genes. We characterized the MHC IIB and the skin microbiota of hellbenders in Missouri, where both subspecies co-occur though not sympatric. We compared the microbiota composition and MHC diversity between both subspecies and investigated whether individual-level MHC diversity, sex and body condition were associated with microbiota composition. Overall, MHC IIB diversity was lower in Ozark hellbenders compared to the eastern subspecies. Multivariate statistical comparisons identified microbiota differentiation between Ozark and eastern hellbenders. MHC IIB allele presence/absence, allele divergence, body composition and sex defined grouping of hellbender microbiotas within populations. Differentiation of the cutaneous microbiotas and MHC IIB genes between eastern and Ozark hellbenders suggests that differences exist in immunity between the two subspecies. This study demonstrates how simultaneous assessments of host genetic traits and microbiotas can inform patterns of microbial community structure in natural systems.


Assuntos
Microbiota/genética , Pele/microbiologia , Urodelos/microbiologia , Alelos , Animais , Imunogenética , Pele/imunologia , Urodelos/genética , Urodelos/imunologia , Urodelos/fisiologia
20.
Transbound Emerg Dis ; 65(2): e478-e488, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29341499

RESUMO

Batrachochytrium salamandrivorans (Bsal) poses a major threat to amphibian, and more specifically caudata, diversity. Bsal is currently spreading through Europe, and mitigation measures aimed at stopping its spread and preventing its introduction into naïve environments are urgently needed. Screening for presence of Bsal and diagnosis of Bsal-induced disease in amphibians are essential core components of effective mitigation plans. Therefore, the aim of this study was to present an overview of all Bsal diagnostic tools together with their limitations and to suggest guidelines to allow uniform interpretation. Here, we investigate the use of different diagnostic tools in post-mortem detection of Bsal and whether competition between Bd and Bsal occurs in the species-specific Bd and Bsal duplex real-time PCR. We also investigate the diagnostic sensitivity, diagnostic specificity and reproducibility of the Bsal real-time PCR and show the use of immunohistochemistry in diagnosis of Bsal-induced chytridiomycosis in amphibian samples stored in formaldehyde. Additionally, we have drawn up guidelines for the use and interpretation of the different diagnostic tools for Bsal currently available, to facilitate standardization of execution and interpretation.


Assuntos
Anticorpos Antifúngicos/sangue , Quitridiomicetos/genética , Quitridiomicetos/imunologia , Micoses/diagnóstico , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Urodelos/microbiologia , Animais , Quitridiomicetos/isolamento & purificação , DNA Fúngico/genética , Europa (Continente) , Guias como Assunto , Imuno-Histoquímica/veterinária , Micoses/imunologia , Coelhos , Reprodutibilidade dos Testes , Especificidade da Espécie
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