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1.
Nat Commun ; 11(1): 4905, 2020 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-32999288

RESUMO

Transcription factor (TF) IIIC is a conserved eukaryotic six-subunit protein complex with dual function. It serves as a general TF for most RNA polymerase (Pol) III genes by recruiting TFIIIB, but it is also involved in chromatin organization and regulation of Pol II genes through interaction with CTCF and condensin II. Here, we report the structure of the S. cerevisiae TFIIIC subcomplex τA, which contains the most conserved subunits of TFIIIC and is responsible for recruitment of TFIIIB and transcription start site (TSS) selection at Pol III genes. We show that τA binding to its promoter is auto-inhibited by a disordered acidic tail of subunit τ95. We further provide a negative-stain reconstruction of τA bound to the TFIIIB subunits Brf1 and TBP. This shows that a ruler element in τA achieves positioning of TFIIIB upstream of the TSS, and suggests remodeling of the complex during assembly of TFIIIB by TFIIIC.


Assuntos
Regulação Fúngica da Expressão Gênica , RNA Polimerase III/metabolismo , Proteínas de Saccharomyces cerevisiae/ultraestrutura , Saccharomyces cerevisiae/genética , Fatores de Transcrição TFIII/ultraestrutura , Animais , Linhagem Celular , Microscopia Crioeletrônica , DNA Fúngico/genética , DNA Fúngico/metabolismo , Genes Fúngicos/genética , Insetos , Domínios Proteicos , Multimerização Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/ultraestrutura , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/isolamento & purificação , Proteínas de Saccharomyces cerevisiae/metabolismo , Fator de Transcrição TFIIIB/genética , Fator de Transcrição TFIIIB/isolamento & purificação , Fator de Transcrição TFIIIB/metabolismo , Fatores de Transcrição TFIII/genética , Fatores de Transcrição TFIII/isolamento & purificação , Fatores de Transcrição TFIII/metabolismo , Sítio de Iniciação de Transcrição , Iniciação da Transcrição Genética
2.
Plant Dis ; 104(10): 2551-2555, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32804013

RESUMO

Ormosia pinnata (Lour.) Merr. is an important tree used for landscape and plant recovery of barren slopes in China. During an investigation of plant disease on landscape trees in 2018, a dieback was observed on O. pinnata trees in Guangzhou, Guangdong Province, China. Symptoms were characterized by initial dryness of the twigs and eventual death of the whole branch of the tree. Isolations from symptomatic branches yielded 13 isolates including two main morphotypes. Pathogenicity tests showed that isolate GDOP1 from Type I caused dieback of O. pinnata. Based on morphological characteristics and molecular analysis of the internal transcribed spacer rDNA (ITS1-5.8S-ITS2) and partial sequence of the translation elongation factor 1α (EF1-α), the fungus causing dieback on O. pinnata was identified as Lasiodiplodia pseudotheobromae. This is the first report of L. pseudotheobromae infecting O. pinnata in the world.


Assuntos
Ascomicetos/genética , China , DNA Fúngico/genética , Filogenia , Doenças das Plantas
3.
Plant Dis ; 104(10): 2571-2584, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32816625

RESUMO

In recent years in China, leaf spot caused by Colletotrichum species has been an emerging disease of Philodendron tatei cv. Congo. From 2016 to 2019, typical symptoms, appearing as circular or ovoid, sunken, and brown lesions with a yellow halo, were commonly observed on P. tatei cv. Congo in and around Lanzhou, Gansu Province, China. Conidiomata were often visible on infected leaf surfaces. Leaf disease incidence was approximately 5 to 20%. A total of 126 single-spored Colletotrichum isolates were obtained from leaf lesions. Multilocus phylogenetic relationships were analyzed based on seven genomic loci (ITS, ACT, GAPDH, HIS3, CAL, CHS-1, and TUB2) and the morphological characters of the isolates determined. These isolates were identified as three Colletotrichum species in this study. A further 93 isolates, accounting for 74% of all Colletotrichum isolates, were described as new species and named as Colletotrichum philodendricola sp. nov. after the host plant genus name, Philodendron; another two isolates were named as C. pseudoboninense sp. nov. based on phylogenetic and morphological relativeness to C. boninense; the other 31 isolates, belonging to the C. orchidearum species complex, were identified as a known species-C. orchidearum. Both novel species C. philodendricola and C. pseudoboninense belong to the C. boninense species complex. Pathogenicity tests by both spray and point inoculations confirmed that all three species could infect leaves of P. tatei cv. Congo. For spray inoculation, the mean infection rate of leaves on the three species was only 4.7% (0 to 12%), and the size on lesions was mostly 1 to 2 mm in length. For point inoculation, 30 days after nonwounding inoculation, the infection rate on leaves was 0 to 35%; in wounding inoculation, the infection rate of leaves was 35 to 65%; wounding in healthy leaves greatly enhanced the pathogenicity of these three species to P. tatei cv. Congo; however, the sizes of lesions among the three species were not significantly different. To our knowledge, this is the first report of Colletotrichum species associated with anthracnose diseases on P. tatei cv. Congo. Results obtained in this study will assist the disease prevention and appropriate management strategies.


Assuntos
Colletotrichum/genética , Philodendron , China , Congo , DNA Fúngico/genética , Filogenia , Doenças das Plantas , Virulência
4.
Int J Syst Evol Microbiol ; 70(8): 4798-4807, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32783804

RESUMO

Leptographium panxianense and L. puerense are proposed as new taxa based on sequence data and morphological characters. The phylogenetic analyses based on ITS2-partial LSU rDNA region, ß-tubulin and elongation factor 1-α genes showed that L. panxianense and L. puerense formed well-supported clades and were closely related to L. yunnanense, L. wushanense and L. conjunctum, and then nested within the L. lundbergii complex. The two species differ in their conidial size and shape. The conidia of L. panxianense are larger than those of L. puerense while the conidial shape of L. puerense is more ovovoid. The optimal growth temperature of both L. panxianense and L. puerense is at 20 °C, which is different from those of L. yunnanense, L. wushanense and L. conjunctum. Comparison of sequence data and morphological characters confirmed the placement of the two undescribed taxa in the genus of Leptographium.


Assuntos
Besouros/microbiologia , Ophiostomatales/classificação , Filogenia , Pinus , Animais , China , DNA Fúngico/genética , DNA Ribossômico/genética , Técnicas de Tipagem Micológica , Ophiostomatales/isolamento & purificação , Fator 1 de Elongação de Peptídeos/genética , Análise de Sequência de DNA , Esporos Fúngicos , Tubulina (Proteína)/genética
5.
Nat Commun ; 11(1): 4281, 2020 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-32855416

RESUMO

Controlling efficiency and fidelity in the early stage of mitochondrial DNA transcription is crucial for regulating cellular energy metabolism. Conformational transitions of the transcription initiation complex must be central for such control, but how the conformational dynamics progress throughout transcription initiation remains unknown. Here, we use single-molecule fluorescence resonance energy transfer techniques to examine the conformational dynamics of the transcriptional system of yeast mitochondria with single-base resolution. We show that the yeast mitochondrial transcriptional complex dynamically transitions among closed, open, and scrunched states throughout the initiation stage. Then abruptly at position +8, the dynamic states of initiation make a sharp irreversible transition to an unbent conformation with associated promoter release. Remarkably, stalled initiation complexes remain in dynamic scrunching and unscrunching states without dissociating the RNA transcript, implying the existence of backtracking transitions with possible regulatory roles. The dynamic landscape of transcription initiation suggests a kinetically driven regulation of mitochondrial transcription.


Assuntos
Mitocôndrias/genética , Saccharomyces cerevisiae/genética , Iniciação da Transcrição Genética , Trifosfato de Adenosina , DNA Fúngico/genética , RNA Polimerases Dirigidas por DNA/genética , RNA Polimerases Dirigidas por DNA/metabolismo , Transferência Ressonante de Energia de Fluorescência , Mitocôndrias/metabolismo , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , RNA Fúngico/genética , RNA Fúngico/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Imagem Individual de Molécula/métodos , Elongação da Transcrição Genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
6.
Nat Commun ; 11(1): 3907, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32764578

RESUMO

Nucleic acids can fold into G-quadruplex (G4) structures that can fine-tune biological processes. Proteins are required to recognize G4 structures and coordinate their function. Here we identify Zuo1 as a novel G4-binding protein in vitro and in vivo. In vivo in the absence of Zuo1 fewer G4 structures form, cell growth slows and cells become UV sensitive. Subsequent experiments reveal that these cellular changes are due to reduced levels of G4 structures. Zuo1 function at G4 structures results in the recruitment of nucleotide excision repair (NER) factors, which has a positive effect on genome stability. Cells lacking functional NER, as well as Zuo1, accumulate G4 structures, which become accessible to translesion synthesis. Our results suggest a model in which Zuo1 supports NER function and regulates the choice of the DNA repair pathway nearby G4 structures.


Assuntos
Reparo do DNA/fisiologia , Quadruplex G , Chaperonas Moleculares/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Sítios de Ligação/genética , Dano ao DNA , Reparo do DNA/genética , DNA Fúngico/química , DNA Fúngico/genética , DNA Fúngico/metabolismo , Deleção de Genes , Aptidão Genética , Genoma Fúngico , Instabilidade Genômica , Modelos Biológicos , Chaperonas Moleculares/genética , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética
7.
BMC Infect Dis ; 20(1): 527, 2020 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-32698804

RESUMO

BACKGROUND: Conidiobolus spp. (mainly C. coronatus) are the causal agents of rhino-facial conidiobolomycosis, a limited soft tissue infection, which is essentially observed in immunocompetent individuals from tropical areas. Rare cases of invasive conidiobolomycosis due to C. coronatus or other species (C.incongruus, C.lamprauges) have been reported in immunocompromised patients. We report here the first case of invasive pulmonary fungal infection due to Conidiobolus pachyzygosporus in a Swiss patient with onco-haematologic malignancy. CASE PRESENTATION: A 71 year-old female was admitted in a Swiss hospital for induction chemotherapy of acute myeloid leukemia. A chest CT performed during the neutropenic phase identified three well-circumscribed lung lesions consistent with invasive fungal infection, along with a positive 1,3-beta-d-glucan assay in serum. A transbronchial biopsy of the lung lesions revealed large occasionally septate hyphae. A Conidiobolus spp. was detected by direct 18S rDNA in the tissue biopsy and subsequently identified at species level as C. pachyzygosporus by 28S rDNA sequencing. The infection was cured after isavuconazole therapy, recovery of the immune system and surgical resection of lung lesions. CONCLUSIONS: This is the first description of C. pachyzygosporus as human pathogen and second case report of invasive conidiobolomycosis from a European country.


Assuntos
Conidiobolus/genética , Leucemia Mieloide Aguda/complicações , Pneumopatias Fúngicas/complicações , Pneumopatias Fúngicas/diagnóstico , Zigomicose/complicações , Zigomicose/diagnóstico , Idoso , Antifúngicos/uso terapêutico , Biópsia , Conidiobolus/isolamento & purificação , DNA Fúngico/genética , DNA Ribossômico/genética , Feminino , Humanos , Hifas/isolamento & purificação , Hospedeiro Imunocomprometido , Pneumopatias Fúngicas/tratamento farmacológico , Pneumopatias Fúngicas/patologia , Nitrilos/uso terapêutico , Piridinas/uso terapêutico , Suíça , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Triazóis/uso terapêutico , Zigomicose/tratamento farmacológico , Zigomicose/patologia
8.
J Laryngol Otol ; 134(7): 632-635, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32686637

RESUMO

BACKGROUND: Invasive fungal rhinosinusitis is associated with high morbidity and mortality. Rapid pathogen identification is mandatory, but fresh tissue is not always available. A polymerase chain reaction method was designed in order to detect fungi in formalin-fixed paraffin-embedded samples. This was applied to a retrospective series of tissue biopsies from Thai patients with invasive fungal rhinosinusitis. METHODS: Tissue blocks from 64 cases yielded adequate DNA. Three sequential polymerase chain reaction were performed: ZP3 (housekeeping gene) and panfungal polymerase chain reactions, and a differentiating polymerase chain reaction based on the 5.8s ribosomal RNA and internal transcribed spacer 2 regions. The polymerase chain reaction products were then sequenced. RESULTS: Polymerase chain reaction identified a fungal pathogen in 20 of 64 cases (31 per cent). Aspergillus species was the most common cause of invasive fungal rhinosinusitis (nine cases). Other causes included candida (n = 4), cladosporium (n = 4), mucor (n = 1), alternaria (n = 1) and dendryphiella (n = 1) species. CONCLUSION: Polymerase chain reaction can provide rapid identification of fungal pathogens in paraffin-embedded tissue, enabling prompt treatment of invasive fungal rhinosinusitis.


Assuntos
Micoses/microbiologia , Reação em Cadeia da Polimerase/métodos , Rinite/microbiologia , Sinusite/microbiologia , Aspergillus/genética , Biópsia , Candida/genética , Criança , Pré-Escolar , Cladosporium/genética , DNA Fúngico/genética , Humanos , Lactente , Inclusão em Parafina , RNA Ribossômico 5,8S/genética , Estudos Retrospectivos , Rinite/patologia , Sinusite/patologia
9.
Nat Commun ; 11(1): 3664, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32694532

RESUMO

Ethanol is a ubiquitous environmental stressor that is toxic to all lifeforms. Here, we use the model eukaryote Saccharomyces cerevisiae to show that exposure to sublethal ethanol concentrations causes DNA replication stress and an increased mutation rate. Specifically, we find that ethanol slows down replication and affects localization of Mrc1, a conserved protein that helps stabilize the replisome. In addition, ethanol exposure also results in the recruitment of error-prone DNA polymerases to the replication fork. Interestingly, preventing this recruitment through mutagenesis of the PCNA/Pol30 polymerase clamp or deleting specific error-prone polymerases abolishes the mutagenic effect of ethanol. Taken together, this suggests that the mutagenic effect depends on a complex mechanism, where dysfunctional replication forks lead to recruitment of error-prone polymerases. Apart from providing a general mechanistic framework for the mutagenic effect of ethanol, our findings may also provide a route to better understand and prevent ethanol-associated carcinogenesis in higher eukaryotes.


Assuntos
Replicação do DNA/efeitos dos fármacos , DNA Polimerase Dirigida por DNA/metabolismo , Etanol/toxicidade , Taxa de Mutação , Saccharomyces cerevisiae/genética , Sistemas CRISPR-Cas/genética , Proteínas de Ciclo Celular/metabolismo , DNA Fúngico/genética , Mutagênese , Testes de Mutagenicidade , Antígeno Nuclear de Célula em Proliferação/genética , Antígeno Nuclear de Célula em Proliferação/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
10.
Mem Inst Oswaldo Cruz ; 115: e200208, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32696916

RESUMO

Paracoccidioides spp. isolation from environmental samples is rare and hardly reproducible. Molecular techniques have facilitated the fungal detection. However, it can be still difficult. Some strategies to enhance the capacity of DNA detection have been adopted, including the analysis of soil samples belonging to the habitat of animals from which Paracoccidioides spp. have already been isolated, notably armadillo burrows. To date, the detection of Paracoccidioides spp. has not yet been reported from outbreak hotspots. Clusters and outbreaks of acute paracoccidioidomycosis (PCM), usually a more severe clinical form, have currently occurred in urban areas being associated to climate changes, deforestation, and great constructions. These occurrences potentially signalise the fungus' environmental niche, a riddle not yet solved. The authors performed an environmental investigation in a deeply disturbed area, after a highway construction in Rio de Janeiro, Brazil, where a recent outbreak of acute PCM occurred. Specific DNA sequences of Paracoccidioides brasiliensis were detected in shallow soil samples around the highway, reinforcing the association between the road construction and this PCM outbreak.


Assuntos
Tatus , DNA Fúngico/genética , Paracoccidioides/isolamento & purificação , Paracoccidioidomicose/microbiologia , Animais , Sequência de Bases , Brasil , Ecossistema , Paracoccidioides/genética , Paracoccidioides/crescimento & desenvolvimento , Análise de Sequência de DNA , Microbiologia do Solo
11.
Int J Syst Evol Microbiol ; 70(8): 4458-4469, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32674752

RESUMO

Four new yeast species belonging to the genus Apiotrichum and two new yeast species belonging to Cutaneotrichosporon are described for strains isolated from guano samples from bat-inhabited caves in Japan. In 2005, we reported these isolates as Trichosporon species based on sequence analyses of the D1/D2 domain of large subunit (LSU) rRNA genes according to available basidiomycetous yeast classification criteria; however, to date, they have not been officially published as new species with descriptions. Their phylogenetic positions have been reanalysed based on comparison of internal transcribed spacer (ITS) region sequences (including the 5.8S rRNA gene) and the D1/D2 domain of the LSU rRNA gene with those of known species; we confirmed clear separation from previously described species. Physiological and biochemical properties of the isolates also suggest their distinctiveness. Therefore, we describe Apiotrichum akiyoshidainum (holotype JCM 12595T), Apiotrichum chiropterorum (JCM 12594T), Apiotrichum coprophilum (JCM 12596T), Apiotrichum otae (JCM 12593T), Cutaneotrichosporon cavernicola (JCM 12590T) and Cutaneotrichosporon middelhovenii (JCM 12592T) as new species. C. cavernicola showed particularly distinctive morphology including large inflated anomalous cells on the hyphae and germination from the cells, although clear clamp connections on the hyphae were not confirmed. Further study is needed to elucidate the morph of this species.


Assuntos
Basidiomycota/classificação , Quirópteros/microbiologia , Fezes/microbiologia , Filogenia , Animais , Basidiomycota/isolamento & purificação , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Japão , Técnicas de Tipagem Micológica , RNA Ribossômico 5,8S/genética , Análise de Sequência de DNA
12.
Int J Syst Evol Microbiol ; 70(8): 4704-4713, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32697190

RESUMO

Five yeast strains were isolated from soil and sediments collected from Alps and Apennines glaciers during sampling campaigns carried out in summer 2007 and 2017, respectively. Based on morphological and physiological tests and on phylogenetic analyses reconstructed with ITS and D1/D2 sequences, the five strains were considered to belong to two related but hitherto unknown species within the genus Mrakia, in an intermediate position between Mrakia cryoconiti and Mrakia arctica. The names Mrakia stelviica (holotype DBVPG 10734T) and Mrakia montana (holotype DBVPG 10736T) are proposed for the two novel species and a detailed description of their morphological, physiological and phylogenetic features are presented. Both species fermented glucose, sucrose and trehalose, which is an uncommon feature in basidiomycetous yeasts, and showed septate hyphae with teliospore formation.


Assuntos
Basidiomycota/classificação , Camada de Gelo/microbiologia , Filogenia , Animais , Basidiomycota/isolamento & purificação , DNA Fúngico/genética , Itália , Técnicas de Tipagem Micológica , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
13.
Int J Syst Evol Microbiol ; 70(8): 4496-4501, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32628104

RESUMO

Two yeast strains representing a novel species in the basidiomycetous yeast genus Naganishia were isolated from flowers of Sorbaria sorbifolia collected in Beijing Olympic Forest Park, PR China. Results of multi-gene phylogenetic analysis indicated that the two strains were closely related to the type strains of Naganishia bhutanensis (CBS 6294T) and Naganishia antarctica (CBS 7687T). However, the new isolates differed from N. bhutanensis CBS 6294T by 1.79 % sequence divergence in the D1/D2 domain (11 nt substitutions and three indels), and 2.42 % (15 nt differences and one indel) to N. antarctica CBS 7687T. In the ITS region, the new isolates showed 1.15 % divergence (7 nt substitutions and one indel) to N. bhutanensis CBS 6294T and 0.92 % divergence (5 nt substitutions and no indels) to N. antarctica CBS 7687T. A phylogenetic analysis employing the sequences of six genes (D1/D2 domain of large subunit rDNA, ITS, small subunit rDNA, two subunits of the RNA polymerase II and elongation factor-1α) indicated that the novel species belonged to the genus Naganishia and formed a well-supported clade with N. bhutanensis, N. antarctica and N. indica. Moreover, the two strains differed from their closest relatives by the ability to grow on distinct carbon and nitrogen sources and ability to grow at 30 °C. On the basis of these findings, we propose a novel species in the genus Naganishia (Filobasidiales), Naganishia floricola sp. nov. (holotype CGMCC 2.5856).


Assuntos
Basidiomycota/classificação , Flores/microbiologia , Filogenia , Rosaceae/microbiologia , Basidiomycota/isolamento & purificação , China , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Técnicas de Tipagem Micológica , Análise de Sequência de DNA
14.
PLoS Negl Trop Dis ; 14(6): e0008293, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32569279

RESUMO

Enterocytozoon bieneusi is the mainly pathologies or intestinal disorders that causes approximately 90% of reported cases of human microsporidiosis. To understand the prevalence and genotype distribution of E. bieneusi in the Xinjiang Uygur Autonomous Region, China, 609 fecal samples were collected from children in kindergarten in Southern Xinjiang and screened for this pathogen by PCR and sequencing of the internal transcribed spacer (ITS). Thirty-six fecal samples (5.9%, 36/609) were positive for E. bieneusi, with the highest prevalence observed in children from Yopurga (17.5%, 11/63). Nine genotypes were identified, of which six were known (A, CHN6, D, EbpA, KB-1, and NIA1) and three were novel (CXJH1, CXJH2 and CXJH3). Genotype NIA1 was most prevalent (52.8%, 19/36), followed by genotypes D (16.7%, 6/36), A (8.3%, 3/36), and EbpA (8.3%, 3/36). The remaining five genotypes were detected in one sample each. Phylogenetic analysis revealed that the E. bieneusi isolates clustered into two groups, one consisting of six genotypes (Group 1: A, CXJH1, D, EbpA, KB-1, and NIA1) and another consisting of three genotypes (Group 2: CHN6, CXJH2, and CXJH3). Our results confirmed that infection of E. bieneusi unusual dominant genotype NIA1 occurs in children in Xinjiang, China. Further epidemiological studies must be conducted to clarify potential sources of E. bieneusi infection in this area.


Assuntos
Enterocytozoon/genética , Variação Genética , Microsporidiose/epidemiologia , Criança , Pré-Escolar , China/epidemiologia , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Enterocytozoon/isolamento & purificação , Fezes/microbiologia , Feminino , Genótipo , Humanos , Masculino , Tipagem de Sequências Multilocus , Filogenia , Reação em Cadeia da Polimerase , Prevalência , Análise de Sequência de DNA
15.
Int J Syst Evol Microbiol ; 70(7): 4378-4383, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32584748

RESUMO

Four isolates of two novel ascosporogenous species belonging to the clade Starmera were obtained from cactus tissues and rotting wood in Brazil. Results of analyses of the sequences of the ITS and D1/D2 domains of the large subunit rRNA gene indicated that the two isolates of the cactophilic species are related to Starmera caribaea and Starmera pilosocereana, yeasts that are associated with cacti and require an organic source of sulfur for growth. We propose the novel species Starmera foglemanii sp. nov. (CBS 16113T; MycoBank number: MB 834400) to accommodate these isolates. The other two isolates are phylogenetically related to Candida dendrica, Candida laemsonensis and Candida berthetii, also in the Starmera clade. The novel species name Starmera ilhagrandensis sp. nov. (CBS 16316T; MycoBank number: MB 834402) is proposed for this species.


Assuntos
Cactaceae/microbiologia , Filogenia , Saccharomycetales/classificação , Madeira/microbiologia , Brasil , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Técnicas de Tipagem Micológica , Saccharomycetales/isolamento & purificação , Análise de Sequência de DNA
16.
Int J Syst Evol Microbiol ; 70(7): 4217-4223, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32589574

RESUMO

Five yeast strains were isolated from the gut of the groundbeetle Pterostichus gebleri and rotting wood, which were collected from two different localities in China. These strains were identified as representing two novel species of the genus Blastobotrys through comparison of sequences in the D1/D2 domains of the LSU rRNA gene and other taxonomic characteristics. Blastobotrys baotianmanensis sp. nov. produces two to three spherical ascospores per ascus, and is most closely related to the type strains of B. elegans, B. capitulata, B. arbuscula, and an undescribed species represented by strain BG02-7-20-006A-3-1. Blastobotrys baotianmanensis sp. nov. differed from these strains by 3.6-8.4 % divergence (21-46 substitutions and 0-4 gaps) in the D1/D2 sequences. Blastobotrys xishuangbannaensis f.a., sp. nov. is closely related to B. nivea, B. elegans and B. aristata but the formation of ascospores was not observed on various sporulation media, and it differed from its relatives by 6.2-8.5 % divergence (34-43 substitutions and 2-6 gaps) in the D1/D2 sequences. The holotype of Blastobotrys baotianmanensis sp. nov. is NYNU 1581 and the holotype of Blastobotrys xishuangbannaensis f.a., sp. nov. is NYNU 181030.


Assuntos
Besouros/microbiologia , Filogenia , Saccharomycetales/classificação , Madeira/microbiologia , Animais , China , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Técnicas de Tipagem Micológica , Saccharomycetales/isolamento & purificação , Análise de Sequência de DNA , Esporos Fúngicos
17.
Mol Cell Biol ; 40(17)2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32541066

RESUMO

Rad3 is the orthologue of ATR and the sensor kinase of the DNA replication checkpoint in Schizosaccharomyces pombe Under replication stress, it initiates checkpoint signaling at the forks necessary for maintaining genome stability and cell survival. To better understand the checkpoint initiation process, we have carried out a genetic screen in fission yeast by random mutation of the genome, looking for mutants defective in response to the replication stress induced by hydroxyurea. In addition to the previously reported mutant with a C-to-Y change at position 307 encoded by tel2 (tel2-C307Y mutant) (Y.-J. Xu, S. Khan, A. C. Didier, M. Wozniak, et al., Mol Cell Biol 39:e00175-19, 2019, https://doi.org/10.1128/MCB.00175-19), this screen has identified six mutations in rqh1 encoding a RecQ DNA helicase. Surprisingly, these rqh1 mutations, except for a start codon mutation, are all in the helicase domain, indicating that the helicase activity of Rqh1 plays an important role in the replication checkpoint. In support of this notion, integration of two helicase-inactive mutations or deletion of rqh1 generated a similar Rad3 signaling defect, and heterologous expression of human RECQ1, BLM, and RECQ4 restored the Rad3 signaling and partially rescued a rqh1 helicase mutant. Therefore, the replication checkpoint function of Rqh1 is highly conserved, and mutations in the helicase domain of these human enzymes may cause the checkpoint defect and contribute to the cancer predisposition syndromes.


Assuntos
Quinase do Ponto de Checagem 2/metabolismo , DNA Helicases/metabolismo , Replicação do DNA , DNA Fúngico/biossíntese , Proteínas de Schizosaccharomyces pombe/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proteínas de Ciclo Celular/metabolismo , Quinase do Ponto de Checagem 2/genética , DNA Helicases/genética , DNA Fúngico/genética , DNA Fúngico/metabolismo , Instabilidade Genômica , Hidroxiureia/farmacologia , Proteínas Quinases/metabolismo , RecQ Helicases/genética , RecQ Helicases/metabolismo , Schizosaccharomyces/metabolismo , Proteínas de Schizosaccharomyces pombe/genética , Transdução de Sinais/efeitos dos fármacos
18.
Science ; 368(6495): 1135-1140, 2020 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-32499444

RESUMO

Determining where an object has been is a fundamental challenge for human health, commerce, and food safety. Location-specific microbes in principle offer a cheap and sensitive way to determine object provenance. We created a synthetic, scalable microbial spore system that identifies object provenance in under 1 hour at meter-scale resolution and near single-spore sensitivity and can be safely introduced into and recovered from the environment. This system solves the key challenges in object provenance: persistence in the environment, scalability, rapid and facile decoding, and biocontainment. Our system is compatible with SHERLOCK, a Cas13a RNA-guided nucleic acid detection assay, facilitating its implementation in a wide range of applications.


Assuntos
Código de Barras de DNA Taxonômico/métodos , DNA Bacteriano/isolamento & purificação , DNA Fúngico/isolamento & purificação , Microbiologia Ambiental , Microbiota/genética , Esporos/genética , Sistemas CRISPR-Cas , DNA Bacteriano/genética , DNA Fúngico/genética , RNA Guia
19.
Int J Food Microbiol ; 331: 108712, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-32563775

RESUMO

The bread-making quality of wheat depends on the viscoelastic properties of the dough in which gluten proteins play an important role. The quality of gluten proteins is influenced by the genetics of the different wheat varieties and environmental factors. Occasionally, a near complete loss of gluten strength, measured as the maximum resistance towards stretching (Rmax), is observed in grain lots of Norwegian wheat. It is hypothesized that the loss of gluten quality is caused by degradation of gluten proteins by fungal proteases. To identify fungi associated with loss of gluten strength, samples from a selection of wheat grain lots with weak gluten (n = 10, Rmax < 0.3 N) and strong gluten (n = 10, Rmax ≥ 0.6 N) was analyzed for the abundance of fungal operational taxonomic units (OTUs) using DNA metabarcoding of the nuclear ribosomal Internal Transcribed Spacer (ITS) region ITS1. The DNA quantities for a selection of fungal pathogens of wheat, and the total amount of fungal DNA, were analyzed by quantitative PCR (qPCR). The mean level of total fungal DNA was higher in grain samples with weak gluten compared to grain samples with strong gluten. Heightened quantities of DNA from fungi within the Fusarium Head Blight (FHB) complex, i.e. Fusarium avenaceum, Fusarium graminearum, Microdochium majus, and Microdochium nivale, were observed in grain samples with weak gluten compared to those with strong gluten. Microdochium majus was the dominant fungus in the samples with weak gluten. Stepwise regression modeling based on different wheat quality parameters, qPCR data, and the 35 most common OTUs revealed a significant negative association between gluten strength and three OTUs, of which the OTU identified as M. majus was the most abundant. The same analysis also revealed a significant negative relationship between gluten strength and F. avenaceum detected by qPCR, although the DNA levels of this fungus were low compared to those of M. majus. In vitro growth rate studies of a selection of FHB species showed that all the tested isolates were able to grow with gluten as a sole nitrogen source. In addition, proteins secreted by these fungi in liquid cultures were able to hydrolyze gluten substrate proteins in zymograms, confirming their capacity to secrete gluten-degrading proteases. The identification of fungi with potential to influence gluten quality can enable the development of strategies to minimize future problems with gluten strength in food-grade wheat.


Assuntos
Microbiologia de Alimentos , Fungos/classificação , Glutens/química , Triticum/química , Triticum/microbiologia , DNA Fúngico/genética , Grão Comestível/microbiologia , Fungos/genética , Fungos/isolamento & purificação , Fungos/metabolismo , Glutens/metabolismo , Doenças das Plantas/microbiologia , Reação em Cadeia da Polimerase em Tempo Real , Triticum/metabolismo
20.
Mol Cell ; 79(1): 127-139.e4, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32437639

RESUMO

C.neoformans Dnmt5 is an unusually specific maintenance-type CpG methyltransferase (DNMT) that mediates long-term epigenome evolution. It harbors a DNMT domain and SNF2 ATPase domain. We find that the SNF2 domain couples substrate specificity to an ATPase step essential for DNA methylation. Coupling occurs independent of nucleosomes. Hemimethylated DNA preferentially stimulates ATPase activity, and mutating Dnmt5's ATP-binding pocket disproportionately reduces ATPase stimulation by hemimethylated versus unmethylated substrates. Engineered DNA substrates that stabilize a reaction intermediate by mimicking a "flipped-out" conformation of the target cytosine bypass the SNF2 domain's requirement for hemimethylation. This result implies that ATP hydrolysis by the SNF2 domain is coupled to the DNMT domain conformational changes induced by preferred substrates. These findings establish a new role for a SNF2 ATPase: controlling an adjoined enzymatic domain's substrate recognition and catalysis. We speculate that this coupling contributes to the exquisite specificity of Dnmt5 via mechanisms related to kinetic proofreading.


Assuntos
Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , DNA (Citosina-5-)-Metiltransferases/metabolismo , Metilação de DNA , DNA Fúngico/metabolismo , Proteínas Fúngicas/metabolismo , Nucleossomos/metabolismo , Adenosina Trifosfatases/genética , Cryptococcus neoformans/genética , Cryptococcus neoformans/metabolismo , DNA (Citosina-5-)-Metiltransferases/genética , DNA Fúngico/química , DNA Fúngico/genética , Proteínas Fúngicas/genética , Hidrólise , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Especificidade por Substrato , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
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