Publications by authors named "Urayama Syun-Ichi"

Fungi are exploited for fermentation of foods such as cheese, Japanese sake, and soy sauce. However, the diversity of viruses that infect fungi involved in food fermentation is poorly understood. Fermented dried bonito ("katsuobushi") is one of the most important processed marine products in Japan.

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Viruses are genetic elements that parasitize self-replicating cells. Therefore, organisms parasitized by viruses are not limited to animals and plants but also include microorganisms. Among these, viruses that parasitize fungi are known as mycoviruses.

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is a species in the order Mucorales that is known to cause mucormycosis, but it is poorly understood as a host of viruses. Here, we examined 25 clinical strains of for viral infection with a conventional double-stranded RNA (dsRNA) assay using agarose gel electrophoresis (AGE) and the recently established fragmented and primer-ligated dsRNA sequencing (FLDS) protocol. By AGE, five virus-infected strains were detected.

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Talaromyces spp. have a worldwide distribution, are ecologically diverse and have been isolated from numerous different substrates. Talaromyces spp.

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Metatranscriptome sequencing expanded the known diversity of the bacterial RNA virome, suggesting that additional riboviruses infecting bacterial hosts remain to be discovered. Here we employed double-stranded RNA sequencing to recover complete genome sequences of two ribovirus groups from acidic hot springs in Japan. One group, denoted hot spring riboviruses (HsRV), consists of viruses with distinct RNA-directed RNA polymerases (RdRPs) that seem to be intermediates between typical ribovirus RdRPs and viral reverse transcriptases.

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Article Synopsis
  • Heterocapsa circularisquama RNA virus (HcRNAV) is the only cultured RNA virus that infects dinoflagellates, with only two fully sequenced strains (34 and 109).
  • Researchers sequenced a new strain of HcRNAV (strain A8) using a novel method (FLDS), revealing a complete genome of 4457 nucleotides.
  • The study found that strain A8 is a UA-type strain, differing by 80 nucleotides at the 5' end from previously sequenced strains, highlighting FLDS's reliability for terminal sequence determination.
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is a thermo-tolerant, ubiquitous fungus commonly found in food products, indoor environments, soil and clinical samples. It is a well-known biocontrol agent used against phytopathogenic fungi and its metabolites have many industrial applications. Rare reports of related human infections have been found in the medical literature.

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Recent massive metatranscriptome mining substantially expanded the diversity of the bacterial RNA virome, suggesting that additional groups of riboviruses infecting bacterial hosts remain to be discovered. We employed full length double-stranded (ds) RNA sequencing for identification of riboviruses associated with microbial consortia dominated by bacteria and archaea in acidic hot springs in Japan. Whole sequences of two groups of multisegmented riboviruses genomes were obtained.

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Mycoviruses are viruses that infect fungi. Unlike mammalian infectious viruses, their life cycle does not generally have an extracellular stage, and a symbiosis-like relationship is maintained between virus and host fungi. Recently, mycoviruses have been reported to show effects on host fungi, altering biological properties such as growth rate, virulence, drug resistance, and metabolite production.

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Article Synopsis
  • - Current research primarily focuses on RNA viruses in well-studied hosts like animals, plants, and fungi, leaving a gap in our understanding of protist RNA viruses.
  • - A study screened RNA viruses from 30 marine protist isolates and discovered a new virus called Haloplacidia narnavirus 1 (HpNV1).
  • - Phylogenetic analysis identified HpNV1 as a novel member of the Narnaviridae family, suggesting that narnaviruses are more widely spread in Stramenopiles than previously recognized.
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  • This study explores the presence of viruses in wild Basidiomycota mushrooms to understand their ecological role and potential for biotechnological applications, a topic that has been less studied compared to other fungi.
  • Researchers screened 51 fungal isolates for viral content using agarose gel electrophoresis and advanced sequencing techniques, revealing seven virus-like sequences, with five being confirmed as viruses after storage.
  • The study identified and characterized seven new viral genome sequences across different RNA virus families, contributing significant insights into the diversity of viruses found in environmental samples.
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Turfgrass used in various areas of the golf course has been found to present anthracnose disease, which is caused by spp. To obtain potential biological agents, we identified four novel RNA viruses and obtained full-length viral genomes from turfgrass pathogenic spp. in Japan.

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RNA viruses in fungi (mycoviruses) are model systems for understanding the relationships between eukaryotic microorganisms and RNA viruses. To reveal the effects of mycoviruses on host fungi, it is essential to compare the phenotypes between isogenic fungal isolates with or without RNA virus infection. Since active entry machinery for RNA mycoviruses has never been identified, introducing mycoviruses to fungi is a difficult and time-consuming process.

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RNA viruses are distributed throughout various environments, and most have recently been identified by metatranscriptome sequencing. However, due to the high nucleotide diversity of RNA viruses, it is still challenging to identify novel RNA viruses from metatranscriptome data. To overcome this issue, we created a dataset of RNA-dependent RNA polymerase (RdRp) domains that are essential for all RNA viruses belonging to Orthornavirae.

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Fungi are ubiquitously present in our living environment and are responsible for crop and infectious diseases. Developing new antifungal agents is constantly needed for their effective control. Here, we investigated fungal cellular responses to an array of antifungal compounds, including plant- and bacteria-derived antifungal compounds.

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Isolated RNA viruses mainly parasitize eukaryotes. RNA viruses either expand horizontally by infecting hosts (acute type) or coexist with the host and are vertically inherited (persistent type). The significance of persistent-type RNA viruses in environmental viromes (the main hosts are expected to be microbes) was only recently reported because they had previously been overlooked in virology.

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Persistent RNA viruses, which have been suggested to form symbiotic relationships with their hosts, have been reported to occur in eukaryotes, such as plants, fungi, and algae. Based on empirical findings, these viruses may also be present in commercially cultivated macroalgae. Accordingly, the present study aimed to screen red macroalgae (family Bangiaceae conchocelis and Neopyropia yezoensis thallus) and processed nori sheets (N.

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RNA virus populations are not clonal; rather, they comprise a mutant swarm in which sequences are slightly different from the master sequence. Genetic diversity within a population (intrapopulation genetic diversity) is critical for RNA viruses to survive under environmental stresses. Disinfection has become an important practice in the control of pathogenic viruses; however, the impact of intrapopulation genetic diversity on the sensitivity of disinfection, defined as -log (postdisinfected infectious titer/predisinfected titer), has not been elucidated.

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Article Synopsis
  • * The study focused on a co-culture system of two fungi, Aspergillus nidulans and Aspergillus fumigatus, showing that this co-culture increased the production of antibacterial compounds called diphenyl ethers.
  • * Analysis revealed that specific gene clusters were activated in both fungi during co-culturing, leading to unique biosynthesis pathways that differ depending on the type of microorganism they are co-cultured with.
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Heterocapsa circularisquama RNA virus (HcRNAV) is the only dinoflagellate-infecting RNA virus that has been isolated to date. We herein investigated the diversity of the major capsid protein gene of HcRNAV and related viruses using degenerate PCR and in silico ana-lyses. Diverse sequences related to HcRNAV were successfully amplified from marine sediments.

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Fludioxonil and iprodione are effective fungicides widely used for crop protection and are essential for controlling plant pathogenic fungi. The emergence of fungicide-resistant strains of targeted pathogens is regularly monitored, and several cases have been reported. Non-targeted fungi may also be exposed to the fungicide residues in agricultural fields.

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Zooplankton and viruses play a key role in marine ecosystems; however, their interactions have not been examined in detail. In the present study, the diversity of viruses associated with zooplankton collected using a plankton net (mesh size: 100‍ ‍μm) in the subtropical western North Pacific was investigated by fragmented and primer ligated dsRNA sequencing. We obtained 21 and 168 operational taxonomic units (OTUs) of ssRNA and dsRNA viruses, respectively, containing RNA-dependent RNA polymerase (RdRp).

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Article Synopsis
  • Recent studies have challenged the idea that RNA-dependent RNA polymerase (RdRp) is solely encoded by a single open reading frame in non-retro RNA viruses, as divided RdRps have been found in fungal RNA viruses.
  • These divided RdRps feature a common division point with specific motifs, categorized as type I divided RdRp, primarily observed in a particular viral clade.
  • In this study focusing on deep sea-derived fungal strains, a new type II divided RdRp was discovered in Aspergillus tennesseensis narnavirus 1, indicating a greater variety of RdRp structures in viruses than previously recognized.
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Fungal infections are increasingly dangerous because of environmentally dispersed resistance to antifungal drugs. Azoles are commonly used antifungal drugs, but they are also used as fungicides in agriculture, which may enable enrichment of azole-resistant strains of the human pathogen Aspergillus fumigatus in the environment. Understanding of environmental dissemination and enrichment of genetic variation associated with azole resistance in A.

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Although viruses infect various organs and are associated with diseases, there may be many unidentified pathogenic viruses. The recent development of next-generation sequencing technologies has facilitated the establishment of an environmental viral metagenomic approach targeting the intracellular viral genome. However, an efficient method for the detection of a viral genome derived from an RNA virus in animal or human samples has not been established.

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