Hiroyuki Ohta

Hiroyuki Ohta
Ibaraki University · College of Agriculture

PhD

About

183
Publications
25,283
Reads
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3,306
Citations
Citations since 2016
31 Research Items
1271 Citations
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
Introduction
Additional affiliations
April 1998 - present
Tokyo University of Agriculture and Technology
Position
  • Professor (Full)
August 1997 - present
Ibaraki University
Position
  • Professor (Full)
September 1986 - May 1987
University of Groningen
Position
  • visiting researcher

Publications

Publications (183)
Preprint
Full-text available
Thermophilic fungi in Mucorales ( Mucoromycotina ) have the potential to be opportunistic pathogens, causing mucormycosis. Among them, Burkholderiaceae -related endobacteria (BRE) are rarely found and the known range of hosts is limited to Rhizopus spp. The phylogenetic divergence of BRE has recently expanded in other fungal groups such as Mortiere...
Article
Full-text available
The genome sequence of Acidithiobacillus ferrooxidans strain NFP31, which is a chemolithoautotrophic iron-oxidizing bacterium that inhabits acidified volcanic deposits on Mount Oyama, Miyake Island (Miyake-jima), Japan, was determined to identify the genetic characteristics associated with pioneer microbes in newly placed pyroclastic deposits.
Article
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Some mucoromycotan fungi establish symbiotic associations with endohyphal bacteria. Here, the genome of Entomortierella parvispora E1425 (synonymously known as Mortierella parvispora E1425), which harbors a cultured Burkholderiaceae -related endobacterium (BRE) designated Mycoavidus sp. Strain B2-EB, was sequenced. We provide genomic information to...
Article
Root-associated microorganisms play an important role in colonization and subsequent development of pioneer plants on newly exposed substrates such as volcanic deposits. However, there is still lack of an understanding how the root microbiome establishes during a short-term development without apparent soil formation when the pioneer plant colonize...
Article
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Research on Kilauea and O-yama Volcanoes has shown that microbial communities and their activities undergo major shifts in response to plant colonization and that molybdenum-dependent CO oxidizers (Mo-COX) and their activities vary with vegetation and deposit age. Results reported here reveal that anaerobic CO oxidation attributed to nickel-depende...
Article
In organic farming, intensive tillage for weed eliminating may cause physical and biological soil degradation. Weed residue mulch can be used to stabilize the organic carbon in the soil by improving soil aggregation and increasing microbial activity. However, the effectiveness of weed mulch in no-tillage (NT) and conventional tillage (CT) systems r...
Article
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This study attempted the isolation of a novel endobacterium, Mycoavidus sp. B2-EB (JCM 33615), harbored in the fungal host Mortierella parvispora E1425 (JCM 39028). We report the complete genome sequence of this strain, which possesses a reduced genome size with relatively high genome completeness and a streamlined genome structure. The information...
Article
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Bacterial endosymbionts inhabit diverse fungal lineages. Although the number of studies on bacteria is increasing, the mechanisms by which bacteria affect their fungal hosts remain unclear. We herein examined the homothallic isolate, Mortierella sugadairana YTM39, harboring a Burkholderiaceae-related endobacterium, which did not produce sexual spor...
Article
Carbonyl sulfide (COS) is the most abundant sulfur compound in the atmosphere, and, thus, is important in the global sulfur cycle. Soil is a major sink of atmospheric COS and the numerical distribution of soil microorganisms that degrade COS is indispensable for estimating the COS-degrading potential of soil. However, difficulties are associated wi...
Article
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Microbial colonization, followed by succession, on newly exposed volcanic substrates represents the beginning of the development of an early ecosystem. During early succession, colonization by mosses or plants significantly alters the pioneer microbial community composition through the photosynthetic carbon input. To provide further insights into t...
Article
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Legionella spp. exist naturally in association with amoeba in water environments and are known to be the etiological agent of a severe form of pneumonia. To detect diverse Legionella populations in cooling tower water systems, amoebic coculturing was performed for 15 water samples obtained from five different kinds of facilities in six geographical...
Article
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Endofungal bacteria are widespread within the phylum Mucoromycota, and these include Burkholderiaceae-related endobacteria (BRE). However, the prevalence of BRE in Mortierellomycotinan fungi and their phylogenetic divergence remain unclear. Therefore, we examined the prevalence of BRE in diverse species of Mortierella. We surveyed 238 isolates of M...
Article
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Branched nonylphenol (BNP), a degradation product of nonylphenol polyethoxylates, exerts estrogenic effects on various organisms. The genes underlying BNP degradation by Sphingobium amiense DSM 16289T were analyzed by complete genome sequencing and compared with those of the versatile BNP-degrading Sphingobium cloacae JCM 10874T. An opdA homolog (o...
Article
A Rhizobium-related bacterium (Rhizobium sp. VsBac-Y9) is a symbiont living with the dark septate endophytic (DSE) fungus Veronaeopsis simplex Y34. Co-inoculation of Rhizobium sp. VsBac-Y9 with V. simplex Y34 improves the fungal colonization of tomato roots, resulting in a significant increase in aboveground biomass. This study sequenced the comple...
Article
A new species, Mortierella sugadairana, is described for a fungus forming homothallic zygospores with a club-shaped macrosuspensor and a microsuspensor originating from the macrosuspensor. The species was isolated from cool regions in Japan and morphologically and phylogenetically close to a heterothallic species M. parvispora, which is the first s...
Article
Full-text available
Endohyphal bacteria (EHB), dwelling within fungal hyphae, markedly affect the growth and metabolic potential of their hosts. To date, two EHB belonging to the family Burkholderiaceae have been isolated and characterized as new taxa, Burkholderia rhizoxinica (HKI 454T) and Mycoavidus cysteinexigens (B1-EBT), in Japan. Metagenome sequencing was recen...
Article
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Bacteria harbored in/on the hyphae of the dark septate endophyte, Veronaeopsis simplex Y34, were identified as a single Rhizobium species by molecular analyses of bacterial 16S rRNA genes, and were successfully isolated from the endophyte. The Rhizobium-cured fungus was prepared thoroughly by an antibiotic treatment, thereby allowing an examination...
Article
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We report the draft genome sequences of Aggregatibacter actinomycetemcomitans strains 310a (310-TR) and 310b (310-OS). Strain 310a is a clinical isolate with a rough phenotype. Strain 310b is a laboratory-adapted isolate derived from the passage of 310a and displays a smooth phenotype.
Article
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Sphingobium cloacae JCM 10874 T can degrade phenolic endocrine-disrupting chemicals, nonylphenol, and octylphenol. Here, we report the complete genome sequence of the JCM 10874 T strain.
Article
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Streptomyces parvulus 2297, which is a host for site-specific recombination according to actinophage R4, is derived from the type strain ATCC 12434. Species of S. parvulus are known as producers of polypeptide antibiotic actinomycins and have been considered for industrial applications. We herein report for the first time the complete genome sequen...
Article
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An endohyphal bacterium (strain B1-EBT) living in association with the fungus Mortierella elongata FMR23-6 I-B1 was isolated from the fungal cell homogenate and studied for its taxonomic allocation. Cells were Gram-stain-negative, rod-shaped, non-spore-forming, non-motile, and negative for oxidase and catalase. Strain B1-EBT required cysteine for g...
Article
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Newly exposed volcanic substrates contain negligible amounts of organic materials. Heterotrophic organisms in newly formed ecosystems require bioavailable carbon and nitrogen that are provided from CO2 and N2 fixation by pioneer microbes. However, the knowledge of initial ecosystem developmental mechanisms, especially the association between microb...
Article
We investigated butanol recovery by pervaporation separation, using a silicalite-1 membrane, from batch cultures of butanol-producing Clostridium beijerinckii SBP2 grown on sweet sorghum juice as a fermentation medium. The pervaporation system yielded 73% (w/v) butanol from intact feed cultures containing 1% (w/v) butanol, and had a butanol permeat...
Article
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The use of multiple approaches to develop sustainable agriculture is desirable, and should include both regional and global viewpoints. Collaborative approaches between low- and high-latitude countries are particularly desirable because each region has different responsibilities and faces different consequences in the face of climate change. In 201...
Article
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Viable Legionella spp. in environmental water samples were characterized phylogenetically by a clone library analysis combining the use of ethidium monoazide and quantitative PCR. To examine the diversity of Legionella spp., six cooling tower water samples and three bath water samples were collected and analyzed. A total of 617 clones were analyzed...
Article
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The fungus Mortierella elongata FMR23-6 harbors an endobacterium inside its mycelium. Attempts to isolate the endobacterium from the fungus were not yet successful, but a highly purified bacterial fraction was prepared. Here, we report the draft genome sequence of the endobacterium. Copyright © 2014 Fujimura et al.
Article
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A halo- and organo-sensitive oligotrophic bacterium, designated strain SY-6T, was isolated from humus forest soil at Gyeryong mountain in Korea. The strain was Gram-negative, strictly aerobic, non-motile and formed yellow-pigmented rod colonies on 100-fold diluted nutrient broth. Strain SY-6T grew between pH 6.0 and 7.0 (optimal growth at pH 7.0),...
Article
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The 2000 eruption of Mount Oyama on the island of Miyake (Miyake-jima) created a unique opportunity to study the early ecosystem development on newly exposed terrestrial substrates. In this study, bacterial and fungal communities on 9- and 11-year-old volcanic deposits at poorly to fully vegetation-recovered sites in Miyake-jima, Japan, were charac...
Article
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A thallium-tolerant, aerobic bacterium, designated SK200a-9(T), isolated from a garden soil sample was characterized by polyphasic approaches. A comparative analysis of 16S rRNA gene sequences revealed that strain SK200a-9(T) was affiliated with an uncultivated lineage within the Alphaproteobacteria and the nearest cultivated neighbours were bacter...
Article
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Properties of estuary sediment change dramatically by repetition of flushing events under management of the river flow. The dynamics of fine sediments in the Tonegawa river estuary were studied from analyses of physicochemical properties and bacterial community structure of sediments throughout flushing, static and transitional periods. In flushed...
Article
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Tetracycline (TC) and ampicillin (AMP) resistant bacteria were identified from both fresh and brackish water shrimp farming system, in Bangladesh. Among 78 isolates from freshwater samples, 14.10, 17.95 and 23.8% were found resistant to TC, AMP and TC plus AMP, respectively. On the other hand, isolates from the brackish water samples, the percentag...
Article
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A diazotrophic, acidophilic, iron-oxidizing bacterium, Leptospirillum ferrooxidans, known to be difficult to cultivate, was isolated from a fresh volcanic ash deposit on the island of Miyake, Japan. Here, we report the complete genome sequence of a cultured strain, C2-3.
Article
Full-text available
The soil-inhabiting fungal pathogen Fusarium oxysporum has been an increasing threat to Chinese cabbage (Brassica campestris L.). A dark septate endophytic fungus, Veronaeopsis simplex Y34, isolated from Yaku Island, Japan, was evaluated in vitro for the ability to suppress Fusarium disease. Seedlings grown in the presence of the endophyte showed a...
Article
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An anammox assay involving a (15)N tracer and gas chromatography-mass spectrometry revealed that the potential anammox activity accounted for 1 to 5% of total N2 production in a ravine paddy field, Japan. Among four 4-cm-deep layers, the top layer showed the highest activity. Clone libraries showed that the DNA in the top layer contained sequences...
Article
Full-text available
Microbial colonization on new terrestrial substrates represents the initiation of new soil ecosystem formation. In this study, we analyzed early bacterial communities growing on volcanic ash deposits derived from the 2000 Mount Oyama eruption on the island of Miyake (Miyake-jima), Japan. A site was established in an unvegetated area near the summit...
Article
Ethanol was efficiently produced from three varieties of sweet sorghum using repeated-batch fermentation without pasteurization or acidification. Saccharomyces cerevisiae cells could be recycled in 16 cycles of the fermentation process with good ethanol yields. This technique would make it possible to use a broader range of sweet sorghum varieties...
Article
Full-text available
Ribosomal RNA (rRNA) sequence-based molecular techniques emerged in the late 1980s, which completely changed our general view of microbial life. Coincidentally, the Japanese Society of Microbial Ecology (JSME) was founded, and its official journal "Microbes and Environments (M&E)" was launched, in 1985. Thus, the past 25 years have been an exciting...
Article
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Microscopic and molecular analyses showed the presence of endobacteria inside the mycelia of four out of twelve nitrous oxide (N(2)O)-producing fungal isolates identified as Mortierella elongata. The 16S rRNA gene was successfully amplified with DNA extracted directly from the endobacterium-containing fungal strains and all sequences were related t...
Article
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This study aimed to characterize soil fungal communities in upland rice fields managed with tillage/non-tillage and winter cover-cropping (hairy vetch and cereal rye) practices, using PCR-based molecular methods. The study plots were maintained as upland fields for 5 years and the soils sampled in the second and fifth years were analyzed using T-RF...
Article
A cyanobacterium, semi-filamentous multicellular strain ABRG5-3, was isolated and its unique nature was characterized. This axenic strain formed colonies and was motile on an agarose plate. The 16S rRNA gene of ABRG5-3 exhibited similarities to those of the Limnothrix and Pseudanabaena strains, which are known as filamentous and nonheterocystous cy...