Fighting fungi with fungi: the mycobiome contribution to emerging disease in amphibians

Emerging infectious diseases caused by fungal taxa are increasing and are placing a substantial burden on economies and ecosystems worldwide. Of the emerging fungal diseases, chytridomycosis caused by the fungus Batrachochytrium dendrobatidis (hereafter Bd) is causing a global amphibian extinction. The host frog does have come internal innate immunity, as well as additional resistance through cutaneous microbial communities, leading to the development of probiotic bacterial therapies with mixed results. Unknown is the role of fungi in the protection against Bd infection, and as such, we examined the overlapping roles of bacterial and fungal microbiota in pathogen defense with a combination of high-throughput sequencing and culturing of symbiotic fungi from poison arrow frogs (Dendrobates sp.). Our analyses revealed that abundance of cutaneous fungi contributed more to pathogen defense (~45%), than bacteria (~10%) and these differed from environmental microbiota. Further, we demonstrated that a fungal probiotic therapy did not induce an endocrine-immune reaction in contrast to bacterial probiotics that stressed amphibian hosts and suppressed antimicrobial peptide responses, limiting their long-term colonization potential. Our results suggest that probiotic strategies against amphibian fungal pathogens should refocus on host-associated and environmental fungi such as Penicillium and member of the families Chaetomiaceae and Lasiosphaeriaceae.

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Is overwintering mortality driving enigmatic declines? Evaluating the impacts of trematodes and the amphibian chytrid fungus on an anuran from hatching through overwintering

PLoS ONE ◽

10.1371/journal.pone.0262561 ◽

2022 ◽

Vol 17 (1) ◽

pp. e0262561

Author(s):

Olivia Wetsch ◽

Miranda Strasburg ◽

Jessica McQuigg ◽

Michelle D. Boone

Keyword(s):

Batrachochytrium Dendrobatidis ◽

Species Conservation ◽

Emerging Infectious Diseases ◽

The Novel ◽

Chytrid Fungus ◽

Growth And Survival ◽

Critical Life Events ◽

Overwintering Mortality ◽

Amphibian Chytrid Fungus

Emerging infectious diseases are increasing globally and are an additional challenge to species dealing with native parasites and pathogens. Therefore, understanding the combined effects of infectious agents on hosts is important for species’ conservation and population management. Amphibians are hosts to many parasites and pathogens, including endemic trematode flatworms (e.g., Echinostoma spp.) and the novel pathogenic amphibian chytrid fungus (Batrachochytrium dendrobatidis [Bd]). Our study examined how exposure to trematodes during larval development influenced the consequences of Bd pathogen exposure through critical life events. We found that prior exposure to trematode parasites negatively impacted metamorphosis but did not influence the effect of Bd infection on terrestrial growth and survival. Bd infection alone, however, resulted in significant mortality during overwintering—an annual occurrence for most temperate amphibians. The results of our study indicated overwintering mortality from Bd could provide an explanation for enigmatic declines and highlights the importance of examining the long-term consequences of novel parasite exposure.

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Comparison of different extraction kits to isolate microRNA fromGalleria mellonella(wax moth) larvae infected withMetarhizium brunneum(ARSEF4556)

10.1101/606004 ◽

2019 ◽

Author(s):

Muneefah A. Alenezi ◽

Tariq M. Butt ◽

Daniel C. Eastwood

Keyword(s):

Fungal Pathogens ◽

High Throughput Sequencing ◽

Galleria Mellonella ◽

Host Tissue ◽

Tissue Cultures ◽

Complex Environments ◽

Infected Insect ◽

Sequencing And Expression ◽

Wax Moth

ABSTRACTMicroRNAs (miRNAs) play an important role in regulating gene expression and are involved in developmental processes in animals, plants and fungi. To understand the role of miRNAs in a biological system, it is important to optimise the extraction procedures to obtain high quality and quantity nucleic acid that enable high throughput sequencing and expression analysis. Numerous kit-based miRNA extraction protocols have been optimised generally to single cell or tissue cultures. Fungi, however, often occupy physically and chemically complex environments which miRNA make extraction challenging, such as fungal pathogens interacting within plant or animal host tissue. We used aGalleria mellonella(wax moth) larvae and entomopathogenic fungusMetarhizium brunneum ARSEF 4556host/pathogen model to compare commercially available miRNA extraction kits (Invitrogen PureLink™ miRNA Isolation Kit, Ambion mirVana™miRNA Isolation Kit and Norgen microRNA purification Kit). Our results showed reproducible and significant differences in miRNAs extraction between the kits, with the Invitrogen PureLink™ miRNA Isolation protocol demonstrating the best performance in terms of miRNA quantity, quality and integrity isolated from fungus-infected insect tissue.

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Hsa_circ_0110757 upregulates ITGA1 to facilitate temozolomide resistance in glioma by suppressing hsa-miR-1298-5p

Cell Death and Disease ◽

10.1038/s41419-021-03533-x ◽

2021 ◽

Vol 12 (3) ◽

Author(s):

Haoyu Li ◽

Qing Liu ◽

Zihua Chen ◽

Ming Wu ◽

Chao Zhang ◽

...

Keyword(s):

Tumor Invasion ◽

High Throughput Sequencing ◽

Myeloid Cell ◽

Circular Rnas ◽

Sequencing Analysis ◽

Potential Therapeutic Target

AbstractTemozolomide (TMZ) is the internationally recognized and preferred drug for glioma chemotherapy treatment. However, TMZ resistance in glioma appears after long-term use and is an urgent problem that needs to be solved. Circular RNAs (circRNAs) are noncoding RNAs and play an important role in the pathogenesis and progression of tumors. Hsa_circ_0110757 was identified in TMZ-resistant glioma cells by high-throughput sequencing analysis and was derived from reverse splicing of myeloid cell leukemia-1 (Mcl-1) exons. The role of hsa_circ_0110757 in TMZ-resistant glioma was evaluated both in vitro and in vivo. It was found that hsa_circ_0110757 and ITGA1 are more highly expressed in TMZ-resistant glioma than in TMZ-sensitive glioma. The overexpression of hsa_circ_0110757 in glioma patients treated with TMZ was obviously associated with tumor invasion. This study indicates that hsa_circ_0110757 inhibits glioma cell apoptosis by sponging hsa-miR-1298-5p to promote ITGA1 expression. Thus, hsa_circ_0110757/hsa-miR-1298-5p/ITGA could be a potential therapeutic target for reversing the resistance of glioma to TMZ.

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Probiotic treatment restores protection against lethal fungal infection lost during amphibian captivity

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2016.1553 ◽

2016 ◽

Vol 283 (1839) ◽

pp. 20161553 ◽

Cited By ~ 61

Author(s):

Jordan G. Kueneman ◽

Douglas C. Woodhams ◽

Reid Harris ◽

Holly M. Archer ◽

Rob Knight ◽

...

Keyword(s):

Batrachochytrium Dendrobatidis ◽

Life Stage ◽

Skin Microbiome ◽

Janthinobacterium Lividum ◽

Probiotic Treatment ◽

In Captivity ◽

Boreal Toads ◽

Inhibitory Bacteria

Host-associated microbiomes perform many beneficial functions including resisting pathogens and training the immune system. Here, we show that amphibians developing in captivity lose substantial skin bacterial diversity, primarily due to reduced ongoing input from environmental sources. We combined studies of wild and captive amphibians with a database of over 1 000 strains that allows us to examine antifungal function of the skin microbiome. We tracked skin bacterial communities of 62 endangered boreal toads, Anaxyrus boreas , across 18 time points, four probiotic treatments, and two exposures to the lethal fungal pathogen Batrachochytrium dendrobatidis ( Bd ) in captivity, and compared these to 33 samples collected from wild populations at the same life stage. As the amphibians in captivity lost the Bd -inhibitory bacteria through time, the proportion of individuals exposed to Bd that became infected rose from 33% to 100% in subsequent exposures. Inoculations of the Bd -inhibitory probiotic Janthinobacterium lividum resulted in a 40% increase in survival during the second Bd challenge, indicating that the effect of microbiome depletion was reversible by restoring Bd -inhibitory bacteria. Taken together, this study highlights the functional role of ongoing environmental inputs of skin-associated bacteria in mitigating a devastating amphibian pathogen, and that long-term captivity decreases this defensive function.

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Reservoir frogs: seasonality of Batrachochytrium dendrobatidis infection in robber frogs in Dominica and Montserrat

PeerJ ◽

10.7717/peerj.7021 ◽

2019 ◽

Vol 7 ◽

pp. e7021 ◽

Cited By ~ 4

Author(s):

Michael A. Hudson ◽

Richard A. Griffiths ◽

Lloyd Martin ◽

Calvin Fenton ◽

Sarah-Louise Adams ◽

...

Keyword(s):

Wildlife Conservation ◽

Batrachochytrium Dendrobatidis ◽

Seasonal Pattern ◽

Emerging Infectious Diseases ◽

Seasonal Patterns ◽

Infection Prevalence ◽

Reservoir Species ◽

Reintroduction Success ◽

Species Declines

Emerging infectious diseases are an increasingly important threat to wildlife conservation, with amphibian chytridiomycosis, caused by Batrachochytrium dendrobatidis, the disease most commonly associated with species declines and extinctions. However, some amphibians can be infected with B. dendrobatidis in the absence of disease and can act as reservoirs of the pathogen. We surveyed robber frogs (Eleutherodactylus spp.), potential B. dendrobatidis reservoir species, at three sites on Montserrat, 2011–2013, and on Dominica in 2014, to identify seasonal patterns in B. dendrobatidis infection prevalence and load (B. dendrobatidis genomic equivalents). On Montserrat there was significant seasonality in B. dendrobatidis prevalence and B. dendrobatidis load, both of which were correlated with temperature but not rainfall. B. dendrobatidis prevalence reached 35% in the cooler, drier months but was repeatedly undetectable during the warmer, wetter months. Also, B. dendrobatidis prevalence significantly decreased from 53.2% when the pathogen emerged on Montserrat in 2009 to a maximum 34.8% by 2011, after which it remained stable. On Dominica, where B. dendrobatidis emerged seven years prior to Montserrat, the same seasonal pattern was recorded but at lower prevalence, possibly indicating long-term decline. Understanding the dynamics of disease threats such as chytridiomycosis is key to planning conservation measures. For example, reintroductions of chytridiomycosis-threatened species could be timed to coincide with periods of low B. dendrobatidis infection risk, increasing potential for reintroduction success.

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