RESUMO
The discovery of N6-methyldeoxyadenine (6mA) across eukaryotes led to a search for additional epigenetic mechanisms. However, some studies have highlighted confounding factors that challenge the prevalence of 6mA in eukaryotes. We developed a metagenomic method to quantitatively deconvolve 6mA events from a genomic DNA sample into species of interest, genomic regions, and sources of contamination. Applying this method, we observed high-resolution 6mA deposition in two protozoa. We found that commensal or soil bacteria explained the vast majority of 6mA in insect and plant samples. We found no evidence of high abundance of 6mA in Drosophila, Arabidopsis, or humans. Plasmids used for genetic manipulation, even those from Dam methyltransferase mutant Escherichia coli, could carry abundant 6mA, confounding the evaluation of candidate 6mA methyltransferases and demethylases. On the basis of this work, we advocate for a reassessment of 6mA in eukaryotes.
Assuntos
Metilação de DNA , DNA/química , Desoxiadenosinas/análise , Eucariotos/genética , Animais , Arabidopsis/genética , Neoplasias Encefálicas/genética , Chlamydomonas reinhardtii/genética , DNA/genética , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Fúngico/química , DNA Fúngico/genética , DNA de Protozoário/química , DNA de Protozoário/genética , Drosophila melanogaster/genética , Drosophila melanogaster/microbiologia , Epigênese Genética , Escherichia coli/genética , Eucariotos/metabolismo , Glioblastoma/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Leucócitos Mononucleares/química , Metagenômica , Plasmídeos , Análise de Sequência de DNA , Tetrahymena thermophila/genéticaRESUMO
Mitochondrial RNA polymerases depend on initiation factors, such as TFB2M in humans and Mtf1 in yeast Saccharomyces cerevisiae, for promoter-specific transcription. These factors drive the melting of promoter DNA, but how they support RNA priming and growth was not understood. We show that the flexible C-terminal tails of Mtf1 and TFB2M play a crucial role in RNA priming by aiding template strand alignment in the active site for high-affinity binding of the initiating nucleotides. Using single-molecule fluorescence approaches, we show that the Mtf1 C-tail promotes RNA growth during initiation by stabilizing the scrunched DNA conformation. Additionally, due to its location in the path of the nascent RNA, the C-tail of Mtf1 serves as a sensor of the RNA-DNA hybrid length. Initially, steric clashes of the Mtf1 C-tail with short RNA-DNA hybrids cause abortive synthesis but clashes with longer RNA-DNA trigger conformational changes for the timely release of the promoter DNA to commence the transition into elongation. The remarkable similarities in the functions of the C-tail and σ3.2 finger of the bacterial factor suggest mechanistic convergence of a flexible element in the transcription initiation factor that engages the DNA template for RNA priming and growth and disengages when needed to generate the elongation complex.
Assuntos
DNA Fúngico/genética , Proteínas Mitocondriais/química , Proteínas Mitocondriais/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Moldes Genéticos , Elongação da Transcrição Genética , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo , Sequência de Aminoácidos , Sequência de Bases , Biocatálise , DNA Fúngico/química , Cadeias de Markov , Metiltransferases/química , Metiltransferases/metabolismo , Conformação de Ácido Nucleico , Nucleotídeos/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Conformação Proteica , RNA Fúngico/biossíntese , Deleção de Sequência , Relação Estrutura-Atividade , Iniciação da Transcrição GenéticaRESUMO
We investigate the kinetics of a polymer collapse due to the formation of irreversible cross-links between its monomers. Using the contact probability P(s) as a scale-dependent order parameter depending on the chemical distance s, our simulations show the emergence of a cooperative pearling instability. Namely, the polymer undergoes a sharp conformational transition to a set of absorbing states characterized by a length scale ξ corresponding to the mean pearl size. This length and the transition time depend on the polymer equilibrium dynamics and the cross-linking rate. We confirm experimentally this transition using a DNA conformation capture experiment in yeast.
Assuntos
Modelos Químicos , Polímeros/química , DNA Fúngico/química , Cinética , Conformação Molecular , Método de Monte Carlo , Conformação de Ácido Nucleico , Leveduras/química , Leveduras/genéticaRESUMO
Colletotrichum species associated with citrus fruits are fragmentarily known and it lacks accordingly accurate information on the diversity carried alongside the trade of these commodities from producer countries to Europe. In this study, we investigated the molecular phylogenetic diversity, colonisation, and prevalence of Colletotrichum isolated from asymptomatic and diseased tissues of nine citrus fruit species from 17 geographically diverse countries. Totally 454 isolates were morphoculturally characterised, and multilocus analyses (ACT, ApMat, CHS-1, GAPDH, ITS, TUB2) was performed on a subset of representative morphotype isolates. Results led to the identification of three previously known species (Colletotrichum gloeosporioides, Colletotrichum karstii, Colletotrichum siamense) and one novel lineage comprising endophytic isolates from Citrus maxima. Based on this lineage, Colletotrichum citri-maximae is described as a new species in the Colletotrichum gigasporum complex, and is characterised by a long deletion in the GAPDH sequence, a character shared with three of its phylogenetic sister taxa. Prevalence of Colletotrichum varied among citrus species and was greatest on Citrus sinensis fruits. C. gloeosporioides was the most common species followed by C. siamense. Except for the new species, all other isolated Colletotrichum spp. also colonise citrus leaves, but the overall diversity on fruits may be lower than that of leaves.
Assuntos
Biodiversidade , Citrus sinensis/microbiologia , Citrus/microbiologia , Colletotrichum/classificação , Frutas/microbiologia , Filogenia , Actinas/genética , Teorema de Bayes , Quitina Sintase/genética , Colletotrichum/genética , Colletotrichum/crescimento & desenvolvimento , DNA Fúngico/química , DNA Fúngico/isolamento & purificação , DNA Intergênico/genética , Proteínas Fúngicas/genética , Gliceraldeído-3-Fosfato Desidrogenase (NADP+)(Fosforiladora)/genética , Haplótipos , Funções Verossimilhança , Cadeias de Markov , Folhas de Planta/microbiologia , Tubulina (Proteína)/genéticaRESUMO
As a first description to document the species richness in Dal Lake, a freshwater lake ecosystem in Kashmir valley, an extensive network of sixteen sampling stations with distinguishing features was sampled seasonally for two years. The identification process yielded fifty-one species probably first and new records for this area to date. The taxonomic groups observed were those with species from Ascomycetes (inclusive of yeasts), Basidiomycetes, Blastocladiomycetes, Zygomycetes, and Peronosporomycetes. Each phylum was represented by a single Order, with the exception of the Peronosporomycetes, which was represented by two Orders- Saprolegniales and Pythiales. In the filamentous fungal group, family Trichocomaceae was dominant followed by Saccharomycetaceae, Mucoraceae, Nectriaceae, Tremellaceae and Hypocreaceae. However, in the group of zoosporic & fungal like eukaryotes, family Saprolegniaceae was most dominant followed by Blastocladiaceae and Pythiaceae. A dramatic decrease in fungal load was observed in different seasons with highest colonial load in the summer season and lowest in the winter season. The observed distribution was statistically significant for both the filamentous fungal species (p < 0.01) as well as zoosporic fungi & fungal like eukaryotes (p < 0.05). In order to assess biodiversity patterns of fungi more accurately, it is necessary to repeat such investigations in other areas and to improve the tools for taxonomic identification of these highly diverse but mostly microscopic organisms.
Assuntos
Biodiversidade , Fungos/classificação , Fungos/genética , Lagos/microbiologia , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Índia , Estações do Ano , Análise de Sequência de DNARESUMO
Ophiocordyceps sinensis is a valuable traditional Chinese medicine with a high market price. In this study, a polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) method based on 2 enzymes was developed to distinguish O. sinensis from 6 common counterfeit species. To verify the applicability of this method, we experimentally tested O. sinensis organisms, tablet preparations made from O. sinensis, and cultured mycelia isolated from O. sinensis. To validate the results from this PCR-RFLP method, all real samples were identified by internal transcribed spacer sequencing. This is, to our knowledge, the first time the PCR-RFLP method has been applied to identify O. sinensis. The selection of 2 restrictive enzymes for identification dramatically improved the accuracy and efficiency of this method. It is the great advantage of this method that sampling from either of 2 parts of O. sinensis-the fruiting body or the caterpillar body-would not cause any difference in the final experimental results. Therefore, this method is not only feasible for testing crude drugs of O. sinensis but it is also useful when the crude drugs are broken down into powder or made into tablets, demonstrating the promising prospect of application in quality control.
Assuntos
Ascomicetos/classificação , Ascomicetos/genética , Medicamentos Falsificados/isolamento & purificação , Medicina Tradicional Chinesa/normas , Medicamentos Falsificados/classificação , Medicamentos Falsificados/economia , DNA Fúngico/química , DNA Fúngico/genética , DNA Fúngico/isolamento & purificação , DNA Espaçador Ribossômico/genética , Reação em Cadeia da Polimerase/métodos , Polimorfismo de Fragmento de Restrição , Controle de QualidadeRESUMO
The genus Suillus represents one of the most recognizable groups of mushrooms in conifer forests throughout the Northern Hemisphere. Although for decades the genus has been relatively well defined morphologically, previous molecular phylogenetic assessments have provided important yet preliminary insights into its evolutionary history. We present the first large-scale phylogenetic study of the boundaries of each species in the genus Suillus based on the most current internal transcribed spacer (ITS) barcode sequences available inPUBLIC databases, as well as sequencing of 224 vouchered specimens and cultures, 15 of which were type specimens from North America. We found that species boundaries delimited by morphological data are broadly congruent with those based on ITS sequences. However, some species appear to have been described several times under different names, several species groups cannot be resolved by ITS sequences alone, and undescribed taxa are apparent, especially in Asia. Therefore, we elevated S. tomentosus var. discolor to S. discolor; proposed synonymies of S. neoalbidipes with S. glandulosipes, S. borealis with S. brunnescens, Boletus serotinus and B. solidipes with Suillus elbensis, S. lactifluus with S. granulatus, S. himalayensis with S. americanus; and proposed usage of the names S. clintonianus in the place of the North American S. grevillei, S. weaverae for North American S. granulatus, S. ampliporus in the place of the North American S. cavipes, and S. elbensis in place of the North American S. viscidus. We showed that the majority of Suillus species have strong affinities for particular host genera. Although deep node support was low, geographic differentiation was apparent, with species from North America, Eurasia, and Asia often forming their own clades. Collectively, this comprehensive genus-level phylogenetic integration of currently available Suillus ITS molecular data and metadata will aid future taxonomic and ecological work on an important group of ectomycorrhizal fungi.
Assuntos
Basidiomycota/classificação , Basidiomycota/genética , Filogeografia , América , Ásia , Código de Barras de DNA Taxonômico , DNA Fúngico/química , DNA Fúngico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , América do NorteRESUMO
Yucatán State is dominated by two kinds of soil, named "Black Leptosol" and "Red Leptosol", which are interwoven across the State. In this work, we analyzed the relation between the edaphic characteristics and the bacterial and fungal community structures in these two kinds of Leptosol. The results revealed that Black Leptosol (BlaS) had a higher content of calcium carbonates, organic matter, nitrogen, and phosphorus than Red Leptosol (RedS). The most outstanding difference in the bacterial community structure between BlaS and RedS was that while in BlaS Actinobacteria was the most abundant phylum (43.7%), followed by Acidobacteria (26.9%) and Proteobacteria (23.6%), in RedS the bacterial community was strongly dominated by Acidobacteria (83%). Two fungal phyla were identified in both kinds of soil; Ascomycota, with 77% in BlaS and 56% in RedS, and Basidiomycota, with 22% in RedS and only 0.67% in BlaS. The most relevant difference between the two fungal communities was that excepting for Fusarium sp., all the species they had were different. Thus, in contrast with bacterial communities, where most of the major OTUs were present in both kinds of soil, fungal communities appeared to be unique to each kind of Leptosol.
Assuntos
Bactérias/classificação , Bactérias/genética , Biota , Fungos/classificação , Fungos/genética , Microbiologia do Solo , Solo/química , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Compostos Inorgânicos/análise , México , Compostos Orgânicos/análise , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Species of Russula subsect. Xerampelinae are notoriously difficult to identify and name and have not been subject to molecular study. A group of species, referred to here as the R. clavipes complex, growing in association with Salix, Betula and Populus as well as coniferous tree species from temperate to arctic and alpine habitats, were examined. Analyses of the nuc rDNA internal transcribed spacer (ITS) region and a numerical analysis of morphological characters were used. The R. clavipes complex is a monophyletic group within Russula subsect. Xerampelinae, according to molecular results. The complex includes three species: R. nuoljae is a phylogenetically and morphologically well-supported species while the other two, R. clavipes and R. pascua, are similar based on ITS data and morphology but separate based on their ecology. Russula pseudoolivascens is conspecific with R. clavipes Several combinations of characters traditionally used in the taxonomy of R. subsect. Xerampelinae are inappropriate for species delimitation in this group and the adequacy of the ITS for species identification in this group is discussed. Detailed microscopic observations on the type collection of R. nuoljae are presented and illustrated, along with a key to the European members of R. subsect. Xerampelinae.
Assuntos
Basidiomycota/classificação , Basidiomycota/citologia , Basidiomycota/genética , Basidiomycota/isolamento & purificação , Betula/microbiologia , Análise por Conglomerados , DNA Fúngico/química , DNA Fúngico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Microscopia , Filogenia , Populus/microbiologia , Salix/microbiologia , Análise de Sequência de DNA , Traqueófitas/microbiologiaRESUMO
Endophytic microorganisms inhabit internal plant tissues in the host plant without causing any symptoms or negative effects. Although the diversity of endophytes has been evaluated by both culture-dependent and culture-independent methods, less information is available on yeast communities. Therefore, in this study a culture-independent method was used to examine endophytic yeasts associated with rice leaves based on the large subunit of ribosomal DNA using a semi-nested PCR technique. Sequence analysis indicated that the colonization frequency and the relative species frequency (RF) of endophytic yeast phylotypes were 0.41 and 0.06, respectively, and the majority of the yeast phylotypes were basidiomycetous yeasts. The phylotypes were designated as five known species (Cryptococcus victoriae, Debaryomyces hansenii, Debaryomyces vindobonensis, Meyerozyma guilliermondii and Pseudozyma antarctica), together with seventeen phylotypes closest to Candida metapsilosis, Cryp. foliicola, Cryp. laurentii, Pseudozyma abaconensis, Pseudozyma aphidis and Trichosporon asahii, among which some could be novel species. The most prevalent phylotypes were those closest to Cryp. foliicola (47.5 % RF) followed by D. hansenii (22.8 % RF) and P. antarctica (16.8 % RF). The presence of the phylotypes related to species known for their potential applications as biocontrol agents and plant growth promoting hormone producers suggests that they may have valuable applications. In addition, our findings revealed the occurrence of novel phylotypes at high frequency, which should encourage extensive studies to discover novel yeast species and to understand their roles in the rice leaves.
Assuntos
Endófitos/classificação , Variação Genética , Oryza/microbiologia , Folhas de Planta/microbiologia , Leveduras/classificação , Análise por Conglomerados , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Endófitos/genética , Genes de RNAr , Dados de Sequência Molecular , Filogenia , RNA Fúngico/genética , RNA Ribossômico/genética , Análise de Sequência de DNA , Leveduras/genéticaRESUMO
The epiphytic yeast diversity in rice phyllosphere in Thailand was investigated by a culture-independent technique based on the RFLP pattern and the sequence of the D1/D2 domain of the large subunit rRNA gene. Forty-four samples of rice leaf were collected randomly from six provinces. The DNA was extracted from leaf washing samples and the D1/D2 domain was amplified using PCR technique. The PCR products were cloned and then screened by colony PCR. Of total 1121 clones, 451 clones (40.2 %) revealed the D1/D2 domain sequences closely related to sequences of yeasts in GenBank, and they were clustered into 45 operational taxonomic units (OTUs) at 99 % homology. Of total yeast related clones, 329 clones (72.9 %) were identified as nine known yeast species, which consisted of 314 clones (8 OTUs) in the phylum Basidiomycota including Bullera japonica, Pseudozyma antarctica, Pseudozyma aphidis, Sporobolomyces blumeae, Sporobolomyces carnicolor and Sporobolomyces oryzicola and 15 clones (6 OTUs) in the phylum Ascomycota including Metschnikowia koreensis, Meyerozyma guilliermondii and Wickerhamomyces anomalus. The D1/D2 sequences (122 clones) that could not be identified as known yeast species were closest to 3 and 14 species in Ascomycota and Basidiomycota, respectively, some of which may be new yeast species. The most predominant species detected was P. antarctica (42.6 %) followed by B. japonica (25.9 %) with 63.6 and 22.7 % frequency of occurrence, respectively. The results of OTU richness of each sampling location revealed that climate condition and sampling location could affect epiphytic yeast diversity in rice phyllosphere.
Assuntos
Biodiversidade , Oryza/microbiologia , Leveduras/classificação , Leveduras/isolamento & purificação , Análise por Conglomerados , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Metagenômica , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , RNA Ribossômico/genética , Análise de Sequência de DNA , Tailândia , Leveduras/genéticaRESUMO
A systematized survey was conducted to find soil-borne microbes that degrade cellulose in soils from unique ecosystems, such as the Superpáramo, Páramo, and the High Andean Forest in the Nevados National Natural Park (NNNP), Colombia. These high mountain ecosystems represent extreme environments, such as high levels of solar radiation, low atmospheric pressure, and extreme daily changes in temperature. Cellulolytic activity of the microorganisms was evaluated using qualitative tests, such as growth in selective media followed by staining with congo red and iodine, and quantitative tests to determine the activity of endoglucanase, β-glucosidase, exoglucanase, and total cellulase. Microorganisms were identified using molecular markers, such as the 16S rRNA gene for bacteria and the internal transcribed spacer region (ITS) of ribosomal DNA for fungi. Multivariate statistical analysis (MVA) was used to select microorganisms with high cellulolytic capacity. A total of 108 microorganisms were isolated from the soils and, in general, the enzymatic activities of fungi were higher than those of bacteria. Our results also found that none of the organisms studied were able to degrade all the components of the cellulose and it is therefore suggested that a combination of bacteria and/or fungi with various enzymatic activities be used to obtain high total cellulolytic activity. This study gives an overview of the potential microorganism that could be used for cellulose degradation in various biotechnological applications and for sustainable agricultural waste treatment.
Assuntos
Bactérias/isolamento & purificação , Bactérias/metabolismo , Celulose/metabolismo , Fungos/isolamento & purificação , Fungos/metabolismo , Microbiologia do Solo , Bactérias/classificação , Bactérias/genética , Colômbia , Celulase/análise , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Fúngico/química , DNA Fúngico/genética , DNA de Helmintos/química , DNA de Helmintos/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Fungos/classificação , Fungos/genética , Hidrólise , /genética , Análise de Sequência de DNARESUMO
The prevalence (7.5%, 19/255) and genotypes of Enterocytozoon bieneusi in children of various age categories and clinical presentations were determined herein. The co-occurrence of the known genotypes (CS-4, EbpC, and Henan-IV) in children and pigs in the same study area, the phylogenetic characterization of novel genotypes (NEC1 to NEC5), and the assessment of potential risk factors associated with zoonotic transmission robustly suggested that pigs could be a significant source of human E. bieneusi infections in northeast China.
Assuntos
Enterocytozoon/classificação , Enterocytozoon/genética , Microsporidiose/epidemiologia , Zoonoses/epidemiologia , Animais , Criança , Pré-Escolar , China/epidemiologia , DNA Fúngico/química , DNA Fúngico/genética , Enterocytozoon/isolamento & purificação , Feminino , Genótipo , Técnicas de Genotipagem , Humanos , Lactente , Recém-Nascido , Masculino , Microsporidiose/microbiologia , Microsporidiose/patologia , Microsporidiose/transmissão , Dados de Sequência Molecular , Prevalência , Medição de Risco , Análise de Sequência de DNA , Suínos , Zoonoses/microbiologia , Zoonoses/patologia , Zoonoses/transmissãoRESUMO
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has proven to be a powerful tool for taxonomic resolution of microorganisms. In this proof-of-concept study, we assessed the effectiveness of this technique to track the current gene sequence-based phylogenetic classification of species in the Metarhizium anisopliae complex. Initially the phylogenetic analysis of 5' strains by sequencing of the 59' end of the TEF-1α gene region revealed seven species within M. anisopliae sensu lato and two varieties outside this complex. Because initial studies on MS profiles from different cell types showed that mycelial fragments or conidia produced on nutrient-poor medium may yield too much background noise, all subsequent spectrometric analyses were performed with acidhydrolyzed conidia from 10-12 d old PDA cultures. The initial MALDI-TOF reference library included protein spectral profiles from nine taxonomically distinct, molecularly identified isolates sharing high genetic homology with the ex-type or ex-epitype isolates of these taxa in Metarhizium. A second reference library added one isolate each for M. anisopliae sensu stricto and M. robertsii. The second, larger reference library (including 11 taxa) allowed nearly perfect MALDI-TOF matching of DNA-based species identification for the 40 remaining isolates molecularly recognized as M. anisopliae sensu stricto (n = 19), M. robertsii (n = 6), M. majus (n = 3), M. lepidiotae (n = 1), M. acridum (n = 3), M. flavoviride var. pemphigi (n = 1), plus seven unidentified strains (six of them phylogenetically close to M. anisopliae sensu stricto and one outside the Metarhizium pingshaense-anisopliae-robertsii-brunneum clade). Due to the increasing frequency of phylogenetically (genomically) based taxonomic revisions of fungi, this approach is especially useful for culture collections, because once the protein profiles of Metarhizium isolates are obtained taxonomic updating of MALDI-TOF library data is easily accomplished by comparing stored profiles with those of newly proposed taxa.
Assuntos
Insetos/microbiologia , Metarhizium/classificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Animais , Sequência de Bases , Análise por Conglomerados , Custos e Análise de Custo , DNA Fúngico/química , DNA Fúngico/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Metarhizium/genética , Metarhizium/isolamento & purificação , Metarhizium/metabolismo , Dados de Sequência Molecular , Micélio , Técnicas de Tipagem Micológica , Fator 1 de Elongação de Peptídeos/genética , Filogenia , Análise de Sequência de DNA/economia , Análise de Sequência de DNA/normas , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/economia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/normas , Esporos Fúngicos , Fatores de TempoRESUMO
Seven Aspergillus calidoustus isolates from 486 Aspergillus spp. isolates (1.4% overall prevalence) from outdoor/indoor air samples and one isolate from the bronchoalveolar lavage fluid of a patient with pneumonia were obtained. These 8 isolates exhibited reduced susceptibility to triazoles. Preliminary pathogenicity data from BALB/c mice suggest that A. calidoustus can persist in tissues for long periods without causing mortality. Further studies using graded doses of inoculum and immunosuppression models are warranted to gain an understanding of the factors associated with its pathogenicity and virulence.
Assuntos
Microbiologia do Ar , Aspergillus/isolamento & purificação , Animais , Antifúngicos/farmacologia , Aspergillus/efeitos dos fármacos , Aspergillus/patogenicidade , Líquido da Lavagem Broncoalveolar/microbiologia , DNA Fúngico/química , DNA Fúngico/genética , Humanos , Kuweit , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Prevalência , Aspergilose Pulmonar/microbiologia , Análise de Sequência de DNA , Centros de Atenção Terciária , Triazóis/farmacologiaRESUMO
The epidemiology of Candida parapsilosis and the closely related species C. orthopsilosis and C. metapsilosis has changed in recent years, justify the need to identify this complex at the species level. In this study we investigate the intergenic spacer 1 (IGS1) of the ribosomal DNA (rDNA) to evaluate the utility of this gene region as a phylogenetic molecular marker and the suitability of a high-resolution melting (HRM) strategy based on this region for identification of members of the C. parapsilosis spp. complex. We sequenced the IGS1 and the internal transcribed spacer (ITS) regions of the rDNA from 33 C. parapsilosis sensu lato strains. Although both regions are useful in identifying species, comparative sequence analysis showed that the diversity in the IGS1 region was higher than in the ITS sequences. We also developed an HRM analysis that reliably identifies C. parapsilosis spp. complex based on the amplification of 70 bp in the IGS1 region. All isolates were correctly identified with a confidence interval >98%. Our results demonstrate that HRM analysis based on the IGS1 region is a powerful tool for distinguishing C. parapsilosis from cryptic species.
Assuntos
Candida/isolamento & purificação , Candidíase/microbiologia , DNA Espaçador Ribossômico/genética , Técnicas de Tipagem Micológica/métodos , Sequência de Bases , Candida/classificação , Candida/genética , Candidíase/diagnóstico , Intervalos de Confiança , Primers do DNA/genética , DNA Fúngico/química , DNA Fúngico/genética , DNA Espaçador Ribossômico/química , Marcadores Genéticos , Humanos , Dados de Sequência Molecular , Técnicas de Tipagem Micológica/economia , Filogenia , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
Invasive aspergillosis (IA) remains difficult to diagnose in immunocompromised patients, because diagnostic EORTC/MSG criteria are often not met. As biomarkers might elucidate the pathogen, we analysed the performance of an Aspergillus PCR assay in blood for diagnosis of IA in immunocompromised paediatric patients with suspected infections. Ninety-five haemato-oncological paediatric patients were included over a period of 3 years, the underlying diseases consisting of acute leukaemia, solid tumours, non-malignant immunocompromising disorders and haematopoietic stem cell transplantation recipients. We retrospectively analysed 253 consecutive episodes of suspected infections. Thirty-eight patients had possible IA, none of the patients fulfilled EORTC/MSG criteria of probable/proven IA. PCR positivity was observed in 97/967 analyses. Sensitivity, specificity, positive and negative predictive value of the PCR per episode were 34%, 78%, 31% and 81% using possible IA as endpoint. Taken together, an undirected blood screening by Aspergillus-specific PCR is of little diagnostic value in a heterogenous paediatric patient cohort. Harnessing PCR for diagnosis of IA should thus be focused on blood analyses of more homogenous high-risk patients and/or analyses of bronchoalveolar lavage, tissue or cerebrospinal fluid specimens.
Assuntos
Aspergillus/isolamento & purificação , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Aspergilose Pulmonar Invasiva/diagnóstico , Programas de Rastreamento/métodos , Técnicas de Diagnóstico Molecular/métodos , Neoplasias/complicações , Reação em Cadeia da Polimerase/métodos , Adolescente , Aspergillus/genética , Sangue/microbiologia , Criança , Pré-Escolar , DNA Fúngico/sangue , DNA Fúngico/química , DNA Fúngico/genética , Feminino , Humanos , Hospedeiro Imunocomprometido , Lactente , Aspergilose Pulmonar Invasiva/microbiologia , Masculino , Dados de Sequência Molecular , Sensibilidade e Especificidade , Análise de Sequência de DNA , Adulto JovemRESUMO
Tuber macrosporum Vittad. is a truffle with superb organoleptic properties, whose cultivation is still in its infancy. For the first time we have aimed to provide information on ectomycorrhizal communities in natural and cultivated T. macrosporum sites. Ectomycorrhizal morphotypes were identified using ITS nrDNA sequencing and sorted into molecular operational taxonomic unit (MOTU). We detected 16 MOTUs in the T. macrosporum cultivated plantation. Ascomycota were the most abundant (86.4%) with Helvellaceae, Pyronemataceae and Pezizaceae the most common. Twenty-two MOTUs were collected in the natural T. macrosporum site. Basidiomycota morphotypes were plentiful (70.6%) and Thelephoraceae dominated. Each site had different taxa belowground with only T. macrosporum in common, being more abundant in the natural (18.2%) than in the cultivated (14.4%) site. Species richness, Simpson and Shannon diversity indices, taxonomic diversity, distinctness and variation of taxonomic distinctness were lower in the cultivated than in the natural site.
Assuntos
Ascomicetos/classificação , Ascomicetos/isolamento & purificação , Basidiomycota/classificação , Basidiomycota/isolamento & purificação , Biodiversidade , Micorrizas/classificação , Micorrizas/isolamento & purificação , Ascomicetos/genética , Ascomicetos/crescimento & desenvolvimento , Basidiomycota/genética , Basidiomycota/crescimento & desenvolvimento , Análise por Conglomerados , DNA Fúngico/química , DNA Fúngico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Microbiologia Ambiental , Dados de Sequência Molecular , Micorrizas/genética , Micorrizas/crescimento & desenvolvimento , Filogenia , Análise de Sequência de DNARESUMO
A systematized survey was conducted to find soil-borne microbes that degrade cellulose in soils from unique ecosystems, such as the Superpáramo, Páramo, and the High Andean Forest in the Nevados National Natural Park (NNNP), Colombia. These high mountain ecosystems represent extreme environments, such as high levels of solar radiation, low atmospheric pressure, and extreme daily changes in temperature. Cellulolytic activity of the microorganisms was evaluated using qualitative tests, such as growth in selective media followed by staining with congo red and iodine, and quantitative tests to determine the activity of endoglucanase, ß-glucosidase, exoglucanase, and total cellulase. Microorganisms were identified using molecular markers, such as the 16S rRNA gene for bacteria and the internal transcribed spacer region (ITS) of ribosomal DNA for fungi. Multivariate statistical analysis (MVA) was used to select microorganisms with high cellulolytic capacity. A total of 108 microorganisms were isolated from the soils and, in general, the enzymatic activities of fungi were higher than those of bacteria. Our results also found that none of the organisms studied were able to degrade all the components of the cellulose and it is therefore suggested that a combination of bacteria and/or fungi with various enzymatic activities be used to obtain high total cellulolytic activity. This study gives an overview of the potential microorganism that could be used for cellulose degradation in various biotechnological applications and for sustainable agricultural waste treatment.
Assuntos
Bactérias/isolamento & purificação , Bactérias/metabolismo , Celulose/metabolismo , Fungos/isolamento & purificação , Fungos/metabolismo , Microbiologia do Solo , Bactérias/classificação , Bactérias/genética , Celulase/análise , Colômbia , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Fúngico/química , DNA Fúngico/genética , DNA de Helmintos/química , DNA de Helmintos/genética , DNA Ribossômico/química , DNA Ribossômico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Fungos/classificação , Fungos/genética , Hidrólise , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
The genus Aspergillus is a burden to public health due to its ubiquitous presence in the environment, its production of allergens, and wide demographic susceptibility among cystic fibrosis, asthmatic, and immunosuppressed patients. Current methods of detection of Aspergillus colonization and infection rely on lengthy morphological characterization or nonstandardized serological assays that are restricted to identifying a fungal etiology. Collagen-like genes have been shown to exhibit species-specific conservation across the noncollagenous regions as well as strain-specific polymorphism in the collagen-like regions. Here we assess the conserved region of the Aspergillus collagen-like (acl) genes and explore the application of PCR amplicon size-based discrimination among the five most common etiologic species of the Aspergillus genus, including Aspergillus fumigatus, A. flavus, A. nidulans, A. niger, and A. terreus. Genetic polymorphism and phylogenetic analysis of the aclF1 gene were additionally examined among the available strains. Furthermore, the applicability of the PCR-based assay to identification of these five species in cultures derived from sputum and bronchoalveolar fluid from 19 clinical samples was explored. Application of capillary electrophoresis on nanogels was additionally demonstrated to improve the discrimination between Aspergillus species. Overall, this study demonstrated that Aspergillus acl genes could be used as PCR targets to discriminate between clinically relevant Aspergillus species. Future studies aim to utilize the detection of Aspergillus acl genes in PCR and microfluidic applications to determine the sensitivity and specificity for the identification of Aspergillus colonization and invasive aspergillosis in immunocompromised subjects.