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1.
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
2.
Protist ; 171(3): 125738, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32544845

RESUMO

This paper represents a comprehensive study of two new thraustochytrids and a marine Rhodotorula red yeast isolated from Australian coastal waters for their abilities to be a potential renewable feedstock for the nutraceutical, food, fishery and bioenergy industries. Mixotrophic growth of these species was assessed in the presence of different carbon sources: glycerol, glucose, fructose, galactose, xylose, and sucrose, starch, cellulose, malt extract, and potato peels. Up to 14g DW/L (4.6gDW/L-day and 2.8gDW/L-day) of biomass were produced by Aurantiochytrium and Thraustochytrium species, respectively. Thraustochytrids biomass contained up to 33% DW of lipids, rich in omega-3 polyunsaturated docosahexaenoic acid (C22:6, 124mg/g DW); up to 10.2mg/gDW of squalene and up to 61µg/gDW of total carotenoids, composed of astaxanthin, canthaxanthin, echinenone, and ß-carotene. Along with the accumulation of these added-value chemicals in biomass, thraustochytrid representatives showed the ability to secrete extracellular polysaccharide matrixes containing lipids and proteins. Rhodotorula sp lipids (26% DW) were enriched in palmitic acid (C16:0, 18mg/gDW) and oleic acid (C18:1, 41mg/gDW). Carotenoids (87µg/gDW) were mainly represented by ß-carotene (up to 54µg/gDW). Efficient growth on organic and inorganic sources of carbon and nitrogen from natural and anthropogenic wastewater pollutants along with intracellular and extracellular production of valuable nutrients makes the production of valuable chemicals from isolated species economical and sustainable.


Assuntos
Biodegradação Ambiental , Quitridiomicetos , Lipídeos/biossíntese , Rhodotorula , Poluentes da Água/metabolismo , Aciltransferases/metabolismo , Biomassa , Carotenoides/metabolismo , Quitridiomicetos/crescimento & desenvolvimento , Quitridiomicetos/isolamento & purificação , Quitridiomicetos/metabolismo , Ácidos Docosa-Hexaenoicos/biossíntese , Ácidos Graxos Insaturados/biossíntese , Nutrientes/metabolismo , Polissacarídeos/biossíntese , Rhodotorula/crescimento & desenvolvimento , Rhodotorula/isolamento & purificação , Rhodotorula/metabolismo , Água do Mar/microbiologia , Águas Residuárias/microbiologia , Áreas Alagadas
3.
Sci Rep ; 9(1): 18534, 2019 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-31811175

RESUMO

Real-time quantitative PCR studies largely depend on reference genes for the normalization of gene expression. Stable reference genes should be accurately selected in order to obtain reliable results. We here present a study screening commonly used reference genes (TEF1F, α-centractin, Ctsyn1, GAPDH, R6046, APRT and TUB) in the chytrid fungi Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal), which cause the lethal amphibian skin disease chytridiomycosis. We evaluated the stability of the reference gene candidates during different growth stages of the fungi, using different statistical software packages: ΔCT, BestKeeper, GeNorm, NormFinder and RefFinder. In order to reflect the in vivo situation, the stability of the candidates was assessed when taking all growth stages into account. Using an ex-vivo approach, we tested whether the expression of GAPDH, TUB, R6046 and APRT (Bd) and GAPDH, TUB, R6046 and α-centractin (Bsal) remained stable when these fungi came in contact with host tissue. Finally, their role as in vivo reference genes was examined in skin tissue of experimentally infected midwife toads (Alytes obstetricans) (Bd) and fire salamanders (Salamandra salamandra) (Bsal). Summarized, the present study provides guidance for selecting appropriate reference genes when analyzing expression patterns of these fungal organisms during different growth stages and in Bd- or Bsal-infected tissues.


Assuntos
Anfíbios/microbiologia , Quitridiomicetos/isolamento & purificação , Dermatomicoses/veterinária , Genes Fúngicos/genética , Animais , Quitridiomicetos/genética , Dermatomicoses/diagnóstico , Dermatomicoses/microbiologia , Perfilação da Expressão Gênica/métodos , Perfilação da Expressão Gênica/normas , Genes Essenciais/genética , RNA Fúngico/genética , RNA Fúngico/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real/normas
5.
PLoS One ; 14(10): e0222718, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31618214

RESUMO

Outbreaks of emerging infectious diseases are becoming more frequent as climate changes wildlife communities at unprecedented rates, driving population declines and raising concerns for species conservation. One critical disease is the global pandemic of chytridiomycosis in frogs, which can be caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). Although there is clear evidence for Bd-induced mortality across high-elevation frog communities, little attention is given to the role of lowlands in Bd's persistence and spread because low elevations are assumed to be too warm to harbor significant levels of Bd. Here, we report widespread Bd infection across 80 frog species from three sites in the lowland Peruvian Amazon, an area with no documented Bd-related amphibian declines. Despite observing no clinical signs of infection in the field, we found that 24-46% of individuals were infected per site (up to ≈105,000 zoospore equivalents per frog) by three Bd strains from the global pandemic lineage (Bd-GPL). We also found collection site and seasonal effects to be only weak predictors of Bd prevalence and load, with lower elevation and drier habitats marginally decreasing both prevalence and load. We found no further effect of host phylogeny, ecotype, or body size. Our results showing high and widespread prevalence across a lowland tropical ecosystem contradict the expectations based on the global pattern of pathogenicity of Bd that is largely restricted to higher elevations and colder temperatures. These findings imply that the lowlands may play a critical role in the spread and persistence of Bd over time and space.


Assuntos
Altitude , Anuros/microbiologia , Quitridiomicetos/patogenicidade , Micoses/veterinária , Animais , Anuros/genética , Quitridiomicetos/isolamento & purificação , Mudança Climática , Feminino , Masculino , Micoses/epidemiologia , Micoses/microbiologia , Peru , Filogenia , Prevalência , Fatores Sexuais
6.
Ecohealth ; 16(4): 701-711, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31654279

RESUMO

Amphibian declines caused by chytridiomycosis have been severe, but some susceptible populations have persisted or even recovered. Resistance to the causal agent Batrachochytrium dendrobatidis (Bd) could result from alleles of the adaptive immune system. During metamorphosis, however, immune systems may not be fully functional, implying that an effective immune response to Bd may be life-stage dependent. We evaluated the susceptibility of the relict leopard frog (Rana onca) sourced from two areas where Bd was present or absent, and where the populations appeared to show differences in pathogen resistance. We evaluated whether population-level resistance manifested across life stages using challenge experiments with late-stage tadpoles (Gosner stage 31-38), metamorphs (stage 45-46), and juvenile frogs. We used three different Bd isolates including one from wild R. onca to challenge juvenile frogs and focused on the isolate from R. onca to challenge tadpoles and resulting metamorphs. We found that juveniles from the Bd exposed population were 5.5 times more likely to survive Bd infection and 10 times more likely to clear infections than those from the area without Bd. In contrast, and regardless of the source area, we observed 98% survivorship of tadpoles, but only 19% survivorship of resulting metamorphs following re-exposure. Given the low survivorship of exposed metamorphs in the laboratory, we speculate on how resistance characteristics, whether adaptive or innate, that do not manifest at each life stage could develop in the wild. We suggest that seasonal high temperatures during times when metamorphosis appears common may modulate the effects of the pathogen during this most susceptible life stage.


Assuntos
Quitridiomicetos/genética , Quitridiomicetos/isolamento & purificação , Resistência à Doença/genética , Resistência à Doença/imunologia , Micoses/imunologia , Ranidae/genética , Ranidae/imunologia , Animais , Quitridiomicetos/imunologia , Micoses/genética , Micoses/fisiopatologia , Ranidae/microbiologia
7.
PLoS One ; 14(9): e0223020, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31560707

RESUMO

The fungal pathogen Batrachochytrium dendrobatidis (Bd) is the causative agent of chytridiomycosis and has been a key driver in the catastrophic decline of amphibians globally. While many strategies have been proposed to mitigate Bd outbreaks, few have been successful. In recent years, the use of probiotic formulations that protect an amphibian host by killing or inhibiting Bd have shown promise as an effective chytridiomycosis control strategy. The North American bullfrog (Lithobates catesbeianus) is a common carrier of Bd and harbours a diverse skin microbiota that includes lactic acid bacteria (LAB), a microbial group containing species classified as safe and conferring host benefits. We investigated beneficial/probiotic properties: anti-Bd activity, and adhesion and colonisation characteristics (hydrophobicity, biofilm formation and exopolysaccharide-EPS production) in two confirmed LAB (cLAB-Enterococcus gallinarum CRL 1826, Lactococcus garvieae CRL 1828) and 60 presumptive LAB (pLAB) [together named as LABs] isolated from bullfrog skin.We challenged LABs against eight genetically diverse Bd isolates and found that 32% of the LABs inhibited at least one Bd isolate with varying rates of inhibition. Thus, we established a score of sensitivity from highest (BdGPL AVS7) to lowest (BdGPL C2A) for the studied Bd isolates. We further reveal key factors underlying host adhesion and colonisation of LABs. Specifically, 90.3% of LABs exhibited hydrophilic properties that may promote adhesion to the cutaneous mucus, with the remaining isolates (9.7%) being hydrophobic in nature with a surface polarity compatible with colonisation of acidic, basic or both substrate types. We also found that 59.7% of LABs showed EPS synthesis and 66.1% produced biofilm at different levels: 21% weak, 29% moderate, and 16.1% strong. Together all these properties enhance colonisation of the host surface (mucus or epithelial cells) and may confer protective benefits against Bd through competitive exclusion. Correspondence analysis indicated that biofilm synthesis was LABs specific with high aggregating bacteria correlating with strong biofilm producers, and EPS producers being correlated to negative biofilm producing LABs. We performed Random Amplified Polymorphic DNA (RAPD)-PCR analysis and demonstrated a higher degree of genetic diversity among rod-shaped pLAB than cocci. Based on the LAB genetic analysis and specific probiotic selection criteria that involve beneficial properties, we sequenced 16 pLAB which were identified as Pediococcus pentosaceus, Enterococcus thailandicus, Lactobacillus pentosus/L. plantarum, L. brevis, and L. curvatus. Compatibility assays performed with cLAB and the 16 species described above indicate that all tested LAB can be included in a mixed probiotic formula. Based on our analyses, we suggest that E. gallinarum CRL 1826, L. garvieae CRL 1828, and P. pentosaceus 15 and 18B represent optimal probiotic candidates for Bd control and mitigation.


Assuntos
Quitridiomicetos/patogenicidade , Lactobacillales/imunologia , Microbiota/imunologia , Micoses/veterinária , Probióticos/isolamento & purificação , Rana catesbeiana/microbiologia , Animais , Quitridiomicetos/isolamento & purificação , DNA Bacteriano , Lactobacillales/genética , Lactobacillales/isolamento & purificação , Micoses/imunologia , Micoses/microbiologia , Rana catesbeiana/imunologia , Técnica de Amplificação ao Acaso de DNA Polimórfico , Pele/imunologia , Pele/microbiologia
8.
J Zoo Wildl Med ; 50(2): 492-497, 2019 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-31260222

RESUMO

Chytridiomycosis, an infectious disease caused by the fungus Batrachochytrium dendrobatidis (chytrid or Bd), has not been well studied in Oklahoma. This is of particular concern regarding the connection between seasonality and chytrid infection. To further investigate this connection, chytrid prevalence and infection load were quantified within amphibians in central Oklahoma from March to October, across two sites in Oklahoma Co. and two sites in Cleveland Co. The results show a trend between seasonality and chytrid, with spring and fall showing higher prevalence and summer showing lower prevalence, which coincides closely with the preferred chytrid growth temperatures. Additionally, periods of high rainfall in May 2015 are linked to increased chytrid prevalence, as has been suggested by other research. Additionally, species exhibiting high chytrid prevalence follow the results of previous studies: Blanchard's cricket frog (Acris blanchardi), American bullfrog (Rana catesbeiana), and southern leopard frog (Rana sphenocephala).


Assuntos
Anuros/microbiologia , Quitridiomicetos/isolamento & purificação , Animais , Micoses/epidemiologia , Micoses/microbiologia , Oklahoma/epidemiologia , Prevalência , Estações do Ano , Tempo (Meteorologia)
9.
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
10.
Fungal Biol ; 123(6): 471-480, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31126424

RESUMO

Chytrids have long been recognised as important parasites of microalgae in freshwater systems, able to shape the dynamics of blooms, the gene pool of their host and phytoplankton succession. In the sea however, where the presence of these organisms is erratic and ephemeral, studies concerning chytrids are sparse and confined to metabarcoding surveys or microscopy observations. Despite the scarcity of data, chytrid epidemics are supposed to play an important role in marine biogeochemical cycles, being one of the drivers of phytoplankton dynamics. Here we combine microscopy observations and in silico mining of a single-cell whole genome to molecularly and morphologically characterise a novel chytrid parasite of the dominant diatom genus Skeletonema. Morphological observations highlight features of the thallus and ascertain the parasitic nature of the interaction whilst the genetic markers obtained allows for a phylogenetic reconstruction, placing the new species in the order Rhizophydiales. Thanks to the molecular data obtained we are also able to provide a first investigation of the global distribution of this organism by screening the Ocean Sampling Day (OSD) dataset, highlighting a northern transatlantic dissemination.


Assuntos
Quitridiomicetos/isolamento & purificação , Diatomáceas/microbiologia , Quitridiomicetos/classificação , DNA Fúngico , Eutrofização , Tipagem Molecular , Filogenia
11.
Vet Rec ; 184(12): 366-367, 2019 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-30902936

RESUMO

Josh Loeb discusses recent research on the devastating Batrachochytrium salamandrivorans fungus.


Assuntos
Quitridiomicetos/isolamento & purificação , Salamandridae/microbiologia , Animais , Reino Unido
13.
Sci Rep ; 9(1): 2831, 2019 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-30862900

RESUMO

Whether an infectious disease threat to wildlife arises from pathogen introduction or the increased incidence of an already-present agent informs mitigation policy and actions. The prior absence of a pathogen can be difficult to establish, particularly in free-living wildlife. Subsequent to the epidemic emergence of the fungus, Batrachochytrium salamandrivorans (Bsal), in mainland Europe in 2010 and prior to its detection in captive amphibians in the United Kingdom (UK), we tested archived skin swabs using a Bsal-specific qPCR. These samples had been collected in 2011 from 2409 wild newts from ponds across the UK. All swabs were negative for Bsal. Bayesian hierarchical modelling suggests that Bsal was absent from, or present at very low levels in, these ponds at the time of sampling. Additionally, surveillance of newt mortality incidents, 2013-2017, failed to detect Bsal. As this pathogen has been shown to be widespread in British captive amphibian collections, there is an urgent need to raise awareness of the importance of effective biosecurity measures, especially amongst people with captive amphibians, to help minimise the risk of Bsal spreading to the wild. Continued and heightened wild amphibian disease surveillance is a priority to provide an early warning system for potential incursion events.


Assuntos
Animais Selvagens/microbiologia , Quitridiomicetos/isolamento & purificação , Micoses/microbiologia , Anfíbios/microbiologia , Animais , Teorema de Bayes , Quitridiomicetos/genética , Tanques/microbiologia , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reino Unido
14.
Sci Rep ; 9(1): 2340, 2019 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-30787411

RESUMO

Ranaviruses have been identified as the cause of explosive disease outbreaks in amphibians worldwide and can be transmitted between hosts both via direct and indirect contact, in which humans might contribute to the translocation of contaminated material. The aim of this study was to evaluate the possible role of water sports in the human translocation of ranavirus, Batrachochytrium dendrobatidis (Bd), and B. salamandrivorans (Bsal). A total of 234 boats were sampled during the spring Spanish Canoe Championship which took place in Pontillón de Castro, a reservoir with a history of ranavirosis, in May 2017. Boats were tested for the presence of ranavirus and Batrachochytrium spp. DNA, using quantitative real-time polymerase chain reaction techniques (qPCR). A total of 22 swabs (22/234, 9.40%) yielded qPCR-positive results for Ranavirus DNA while Bd or Bsal were not detected in any of the samples. We provide the first evidence that human-related water sports could be a source of ranavirus contamination, providing justification for public disinfecting stations in key areas where human traffic from water sports is high.


Assuntos
Ranavirus/fisiologia , Esportes Aquáticos , Quitridiomicetos/isolamento & purificação , Geografia , Espanha
15.
J Wildl Dis ; 55(3): 668-672, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30768916

RESUMO

Ranaviruses and the fungus Batrachochytrium dendrobatidis are globally important agents of emerging infectious amphibian diseases. Amphibians on Oahu, the Hawaiian Island with the greatest potential for disease introduction through the movement of goods and people, have never been surveyed for ranaviruses or B. dendrobatidis. We surveyed all five species of frogs on Oahu, Hawaii, US for these pathogens. Of 325 individuals sampled from six sites, none were positive for ranavirus. However, we found B. dendrobatidis in a total of four individuals of three species, the cane toad (Bufo marinus), the American bullfrog (Rana catesbeiana), and the greenhouse frog (Eleutherodactylus planirostris), but not in the green and black poison dart frog (Dendrobates auratus) or the Japanese wrinkled frog (Rana rugosa). The apparent lack of ranavirus and low prevalence of B. dendrobatidis are noteworthy given how widespread these pathogens are in terms of both global distribution and host range. Surveillance should continue to document any changes in B. dendrobatidis prevalence or the arrival of ranaviruses in Hawaii.


Assuntos
Bufo marinus/microbiologia , Quitridiomicetos/isolamento & purificação , Espécies Introduzidas , Micoses/veterinária , Ranavirus/isolamento & purificação , Ranidae/microbiologia , Animais , Infecções por Vírus de DNA/epidemiologia , Infecções por Vírus de DNA/veterinária , Infecções por Vírus de DNA/virologia , Hawaii/epidemiologia , Micoses/epidemiologia , Micoses/microbiologia
16.
J Vet Diagn Invest ; 31(2): 246-249, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30661466

RESUMO

Histology is often underappreciated for the detection of the amphibian pathogenic fungus Batrachochytrium dendrobatidis, the cause of the potentially lethal skin disease chytridiomycosis. We evaluated the sensitivity of histology to detect chytrids in 20 wild specimens of 2 frog species from Uruguay that were clinically normal, but confirmed by PCR to be infected by B. dendrobatidis. We detected maturing and sporulated sporangia in 15 of 20 (75%) frogs, which is more sensitive than previously reported for histology. The effort needed to identify chytrids in histologic skin sections of Physalaemus henselii and Pleurodema bibroni required examination of 3.2 and 8.7 mm of skin sections for each frog species, respectively.


Assuntos
Anuros , Quitridiomicetos/isolamento & purificação , Técnicas Histológicas/veterinária , Micoses/veterinária , Animais , Técnicas Histológicas/métodos , Micoses/diagnóstico , Micoses/microbiologia , Uruguai
17.
ISME J ; 13(2): 361-373, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30254321

RESUMO

Management of hyper-virulent generalist pathogens is an emergent global challenge, yet for most disease systems we lack a basic understanding as to why some host species suffer mass mortalities, while others resist epizootics. We studied two sympatric species of frogs from the Colombian Andes, which coexist with the amphibian pathogen Batrachochytrium dendrobatidis (Bd), to understand why some species did not succumb to the infection. We found high Bd prevalence in juveniles for both species, yet infection intensities remained low. We also found that bacterial community composition and host defense peptides are specific to amphibian life stages. We detected abundant Bd-inhibitory skin bacteria across life stages and Bd-inhibitory defense peptides post-metamorphosis in both species. Bd-inhibitory bacteria were proportionally more abundant in adults of both species than in earlier developmental stages. We tested for activity of peptides against the skin microbiota and found that in general peptides did not negatively affect bacterial growth and in some instances facilitated growth. Our results suggest that symbiotic bacteria and antimicrobial peptides may be co-selected for, and that together they contribute to the ability of Andean amphibian species to coexist with the global pandemic lineage of Bd.


Assuntos
Anuros/microbiologia , Quitridiomicetos/isolamento & purificação , Microbiota , Peptídeos/farmacologia , Animais , Anuros/crescimento & desenvolvimento , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Colômbia , Micoses/microbiologia , Micoses/veterinária , Peptídeos/análise , Pele/química , Pele/microbiologia , Simbiose , Simpatria
18.
Environ Microbiol ; 21(1): 374-388, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30411473

RESUMO

Fungi living in sediments ('mycobenthos') are hypothesized to play a role in the degradation of organic matter deposited at the land-sea interface, but the environmental factors influencing the mycobenthos are poorly understood. We used mock community calibrated Illumina sequencing to show that the mycobenthos community structure in a coastal lagoon was significantly changed after exposure to a lignocellulose extract and subsequent development of benthic anoxia over a relatively short (10 h) incubation. Saprotrophic taxa dominated and were selected for under benthic anoxia, specifically Aquamyces (Chytridiomycota) and Orbilia (Ascomycota), implicating these genera as important benthic saprotrophs. Protein encoding genes involved in energy and biomass production from Fungi and the fungal-analogue group Labyrinthulomycetes had the highest increase in expression with the added organic matter compared with all other groups, indicating that lignocellulose stimulates metabolic activity in the mycobenthos. Flavobacteria dominated the active bacterial community that grew rapidly with the lignocellulose extract and crashed sharply upon O2 depletion. Our findings indicate that the diversity, activity and trophic potential of the mycobenthos changes rapidly in response to organic matter and decreasing O2 concentrations, which together with heterotrophic Flavobacteria, undergo 'boom and bust' dynamics during lignocellulose degradation in estuarine ecosystems.


Assuntos
Ascomicetos/crescimento & desenvolvimento , Quitridiomicetos/crescimento & desenvolvimento , Substâncias Húmicas/microbiologia , Lignina/metabolismo , Micobioma/fisiologia , Estramenópilas/crescimento & desenvolvimento , Anaerobiose , Ascomicetos/isolamento & purificação , Biomassa , Quitridiomicetos/isolamento & purificação , Ecossistema , Flavobacteriaceae/crescimento & desenvolvimento , Flavobacteriaceae/metabolismo , Processos Heterotróficos , Oxigênio/metabolismo , Estramenópilas/metabolismo
19.
Ecohealth ; 16(1): 128-140, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30377876

RESUMO

The fungus Batrachochytrium dendrobatidis (Bd) is a generalist amphibian pathogen responsible for chytridiomycosis. It was documented for the first time in Cuba in 2007, the apparent cause of the decline in one species of toad. In a recent survey, Bd was reported only for the highlands of Central Cuba. In the present study, we reexamined the geographic distribution and level of impact of Bd in Cuba by conducting an island-wide sampling in 10 localities and collecting skin swabs from 18 species and 28 environmental samples. We report detection of Bd in 60% of sampled sites and in 58% of sampled taxa. We show that Bd is associated with riparian, arboreal and terrestrial species, and it was estimated to occur in approximately 30% of the aquatic habitats we sampled. In addition, we confirmed that a dying individual of the species Eleutherodactylus casparii was severely infected with Bd. We also rise concern about the endanger toad Peltophryne longinasus and about three species of endemic riparian frogs that were not detected during our surveys. This study demonstrates that this pathogen is widespread throughout Cuba and provides relevant evidence to advance our understanding of its detection in amphibians and the aquatic environment in Cuba and about the occurrence of Bd in species with different ecologies. We provide valuable baseline information for Bd risk assessment and decision-making processes to mitigate its negative impact on Cuban amphibians.


Assuntos
Anfíbios/microbiologia , Quitridiomicetos/isolamento & purificação , Micoses/veterinária , Animais , Clima , Cuba/epidemiologia , DNA Fúngico , Ecossistema , Rios
20.
Mycologia ; 110(5): 811-821, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30274555

RESUMO

Food webs in temporary forest ponds are driven by decomposition of terrestrial inputs. Chytrid fungi are important components of the fungal community, degrading leaf litter in streams reliant on terrestrial inputs and in lake ecosystems where they may stabilize the food web. However, little is known about chytrid fungi in temporary forest ponds. We inventoried the chytrid diversity present in two temporary forest ponds via light microscopy of baited samples and ion semiconductor (Ion Torrent) sequencing of environmental DNA. We quantified trends of chytrid alpha and beta diversity as a function of spatial and temporal factors. A total of 59 chytrid taxa were detected throughout the study. Beta diversity exhibited variation across the sampled months for both the entire fungal community as well as for chytrids alone. Shifts in community composition were also apparent, although diversity metrics and composition patterns did not meet adjusted P values. The results of this study highlight the diversity of chytrid fungi in temporary forest ponds and the need for further studies on the spatial and temporal dynamics of chytrid species.


Assuntos
Biodiversidade , Quitridiomicetos/classificação , Quitridiomicetos/isolamento & purificação , Tanques/microbiologia , Quitridiomicetos/citologia , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Florestas , Genes de RNAr , Microscopia , RNA Fúngico/genética , RNA Ribossômico 28S/genética , Análise de Sequência de DNA
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