Takasumi Hattori

Waseda University, Edo, Tōkyō, Japan

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Publications (12)24.38 Total impact

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    ABSTRACT: trans-Aconitic acid is an unsaturated organic acid and detected in some plants such as soybean and wheat, however it remains unclear how trans-aconitic acid is degraded and/or assimilated by living cells in nature. From soil, we isolated Pseudomonas sp. WU-0701 assimilating trans-aconitic acid as a sole carbon source. In the cell-free extract of Pseudomonas sp. WU-0701, aconitate isomerase (EC, AI) activity was detected. Therefore, it seems likely that strain WU-0701 converts trans-aconitic acid into cis-aconitic acid by AI and assimilates via tricarboxylic acid (TCA) cycle. For characterization of AI from strain WU-0701, we performed purification, determination of enzymatic properties, and gene identification of AI. The molecular mass of AI purified from cell-free extract was estimated to be an approximately 25 kDa by both of SDS-PAGE and gel filtration analyses, indicating that AI is a monomer enzyme. Optimal pH and temperature of purified AI for the reaction were 6.0 and 37°C, respectively. The gene ais encoding AI was cloned based on the N-terminal amino acid sequence of the protein, and Southern blot analysis revealed that only one copy of ais locates on the bacterial genome. The gene ais contains an open reading frame of 786 bp, encoding a polypeptide of 262 amino acids including the N-terminal 22 amino acids as a putative periplasm-targeting signal peptide. It is noteworthy that the amino acid sequence of AI shows 90% and 74% identities to molybdenum ABC transporter substrate-binding proteins of P. psychrotolerans and Xanthomonas albilineans, respectively. This is the first report on purification to homogeneity, characterization and gene identification of AI. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    No preview · Article · Aug 2015 · FEBS Journal
  • Keiichi Kobayashi · Takasumi Hattori · Rie Hayashi · Kohtaro Kirimura
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    ABSTRACT: In the tricarboxylic acid (TCA) cycle, NADP(+)-specific isocitrate dehydrogenase (NADP(+)-ICDH) catalyzes oxidative decarboxylation of isocitric acid to form α-ketoglutaric acid with NADP(+) as a cofactor. We constructed an NADP(+)-ICDH gene (icdA)-overexpressing strain (OPI-1) using Aspergillus niger WU-2223L as a host and examined the effects of increase in NADP(+)-ICDH activity on citric acid production. Under citric acid-producing conditions with glucose as the carbon source, the amounts of citric acid produced and glucose consumed by OPI-1 for the 12-d cultivation period decreased by 18.7 and 10.5%, respectively, compared with those by WU-2223L. These results indicate that the amount of citric acid produced by A. niger can be altered with the NADP(+)-ICDH activity. Therefore, NADP(+)-ICDH is an important regulator of citric acid production in the TCA cycle of A. niger. Thus, we propose that the icdA gene is a potentially valuable tool for modulating citric acid production by metabolic engineering.
    No preview · Article · Jul 2014 · Bioscience Biotechnology and Biochemistry
  • Keiichi Kobayashi · Takasumi Hattori · Yuki Honda · Kohtaro Kirimura
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    ABSTRACT: The filamentous fungus Aspergillus niger is used worldwide in the industrial production of citric acid. However, under specific cultivation conditions, citric acid-producing strains of A. niger accumulate oxalic acid as a by-product. Oxalic acid is used as a chelator, detergent, or tanning agent. Here, we sought to develop oxalic acid hyperproducers using A. niger as a host. To generate oxalic acid hyperproducers by metabolic engineering, transformants overexpressing the oahA gene, encoding oxaloacetate hydrolase (OAH; EC, were constructed in citric acid-producing A. niger WU-2223L as a host. The oxalic acid production capacity of this strain was examined by cultivation of EOAH-1 under conditions appropriate for oxalic acid production with 30 g/l glucose as a carbon source. Under all the cultivation conditions tested, the amount of oxalic acid produced by EOAH-1, a representative oahA-overexpressing transformant, exceeded that produced by A. niger WU-2223L. A. niger WU-2223L and EOAH-1 produced 15.6 and 28.9 g/l oxalic acid, respectively, during the 12-day cultivation period. The yield of oxalic acid for EOAH-1 was 64.2 % of the maximum theoretical yield. Our method for oxalic acid production gave the highest yield of any study reported to date. Therefore, we succeeded in generating oxalic acid hyperproducers by overexpressing a single gene, i.e., oahA, in citric acid-producing A. niger as a host.
    No preview · Article · Mar 2014 · Journal of Industrial Microbiology
  • Keiichi Kobayashi · Takasumi Hattori · Yuki Honda · Kohtaro Kirimura
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    ABSTRACT: Methylcitrate synthase (EC; MCS) is a key enzyme of the methylcitric acid cycle localized in the mitochondria of eukaryotic cells and related to propionic acid metabolism. In this study, cloning of the gene mcsA encoding MCS and heterologous expression of it in Escherichia coli were performed for functional analysis of the MCS of citric acid-producing Aspergillus niger WU-2223L. Only one copy of mcsA (1,495 bp) exists in the A. niger WU-2223L chromosome. It encodes a 51-kDa polypeptide consisting of 465 amino acids containing mitochondrial targeting signal peptides. Purified recombinant MCS showed not only MCS activity (27.6 U/mg) but also citrate synthase (EC; CS) activity (26.8 U/mg). For functional analysis of MCS, mcsA disruptant strain DMCS-1, derived from A. niger WU-2223L, was constructed. Although A. niger WU-2223L showed growth on propionate as sole carbon source, DMCS-1 showed no growth. These results suggest that MCS is an essential enzyme in propionic acid metabolism, and that the methylcitric acid cycle operates functionally in A. niger WU-2223L. To determine whether MCS makes a contribution to citric acid production, citric acid production tests on DMCS-1 were performed. The amount of citric acid produced from glucose consumed by DMCS-1 in citric acid production medium over 12 d of cultivation was on the same level to that by WU-2223L. Thus it was found that MCS made no contribution to citric acid production from glucose in A. niger WU-2223L, although MCS showed CS activity.
    No preview · Article · Jul 2013 · Bioscience Biotechnology and Biochemistry
  • Yuki Honda · Takasumi Hattori · Kohtaro Kirimura
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    ABSTRACT: The citric acid-producing filamentous fungus Aspergillus niger WU-2223L shows cyanide-insensitive respiration catalyzed by alternative oxidase in addition to the cytochrome pathway. Sequence analysis of the 5' flanking region of the alternative oxidase gene (aox1) revealed a potential heat shock element (HSE) and a stress response element (STRE). We have previously confirmed aox1 expression in conidia. In this study, to confirm whether the upstream region of aox1 responds to various stresses, we used a visual expression analysis system for single-cell conidia of the A. niger strain AOXEGFP-1. This strain harbored a fusion gene comprising aox1 and egfp, which encodes the enhanced green fluorescent protein (EGFP). The fluorescence intensity of EGFP increased in conidia of A. niger AOXEGFP-1 that were subjected to heat shock at 35-45 °C, oxidative stress by exposure to 5mM paraquat or 1 mM t-butylhydroperoxide, or osmotic stresses by exposure to 0.5 M KCl or 1.0 M mannitol. These results indicate that the putative HSE and STRE in the upstream region of aox1 directly or indirectly respond to heat shock, oxidative, and osmotic stresses.
    No preview · Article · Dec 2011 · Journal of Bioscience and Bioengineering
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    ABSTRACT: A reversible salicylic acid decarboxylase (Sdc), found in the yeast Trichosporon moniliiforme WU-0401, is applicable for the production of p-aminosalicylic acid (PAS) from m-aminophenol (m-AP). For the high-yield production of PAS, used as an antituberculous agent, we developed F195Y, a genetically engineered Sdc mutant. We succeeded in selectively producing PAS from,n-AP through an enzymatic Kolbe-Schmitt reaction in aqueous solution by using recombinant Escherichia coli cells expressing the gene encoding F195Y. We found that 70 mM PAS was produced at 30 degrees C in 15h with a conversion yield of 70% (mol/mol).
    No preview · Article · Feb 2011 · Chemistry Letters
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    ABSTRACT: Salicylic acid decarboxylase (Sdc) can produce salicylic acid from phenol; it was found in the yeast Trichosporon moniliiforme WU-0401 and was for the first time enzymatically characterized, with the sdc gene heterologously expressed. Sdc catalyzed both reactions: decarboxylation of salicylic acid to phenol and the carboxylation of phenol to form salicylic acid without any byproducts. Both reactions were detected without the addition of any cofactors and occurred even in the presence of oxygen, suggesting that this Sdc is reversible, nonoxidative, and oxygen insensitive. Therefore, it is readily applicable in the selective production of salicylic acid from phenol, the enzymatic Kolbe-Schmitt reaction. The deduced amino acid sequence of the gene, sdc, encoding Sdc comprises 350 amino acid residues corresponding to a 40-kDa protein. The recombinant Escherichia coli BL21(DE3) expressing sdc converted phenol to salicylic acid with a 27% (mol/mol) yield at 30 degrees C for 9h.
    No preview · Article · Feb 2010 · Biochemical and Biophysical Research Communications
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    ABSTRACT: A novel metabolic pathway was found in the yeast Trichosporon moniliiforme WU-0401 for salicylate degradation via phenol as the key intermediate. When 20 mM salicylate was used as the sole carbon source for the growth of strain WU-0401, phenol was detected as a distinct metabolite in the culture broth. Analysis of the products derived from salicylate or phenol through reactions with resting cells and a cell-free extract of strain WU-0401 indicated that salicylate is initially decarboxylated to phenol and then oxidized to catechol, followed by aromatic ring cleavage to form cis-cis muconate.
    No preview · Article · Dec 2009 · Biodegradation
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    Takasumi Hattori · Kuniki Kino · Kohtaro Kirimura
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    ABSTRACT: The citric acid-producing fungus Aspergillus niger WU-2223L possesses a cyanide-insensitive respiratory pathway catalyzed by alternative oxidase. The regulation of the alternative oxidase under the conditions of citric acid production was determined from the transcription level of the alternative oxidase gene (aox1). PCR and Southern blot analyses revealed that there is only one copy of aox1 on the chromosome of WU-2223L and no homologous gene of aox1. To confirm the regulation stage of alternative oxidase, alternative oxidase activities and aox1 transcription levels were measured under several cultivation conditions, including those for citric acid production. On each cultivation day, the changes in the specific activity of the alternative oxidase were found to be comparable to those in the transcription level of aox1. These results indicate that the activity of the alternative oxidase encoded by aox1 is regulated at the transcription stage under the conditions tested for A. niger WU-2223L.
    Preview · Article · Mar 2009 · Current Microbiology
  • Takasumi Hattori · Yuki Honda · Kuniki Kino · Kohtaro Kirimura
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    ABSTRACT: Mycelia of citric acid-producing Aspergillus niger WU-2223L show cyanide-insensitive respiration catalyzed by alternative oxidase. In this study, the constitutive expression of alternative oxidase gene (aox1) even at the stage of single-cell conidium in A. niger WU-2223L was found using the visual expression analysis system of aox1 with green fluorescent protein under microscopy observation.
    No preview · Article · Feb 2008 · Journal of Bioscience and Bioengineering
  • Takasumi Hattori · Shusuke Takahashi · Kuniki Kino · Kohtaro Kirimura

    No preview · Article · Sep 2007 · Journal of Biotechnology
  • Kohtaro Kirimura · Satoshi Ogawa · Takasumi Hattori · Kuniki Kino
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    ABSTRACT: In a citric acid-producing filamentous fungus Aspergillus niger WU-2223L, a cyanide- and antimycin A-insensitive and salicylhydroxamic acid-sensitive respiratory pathway functions in the mitochondria besides the cytochrome pathway and is catalyzed by alternative oxidase (AOX). We constructed an A. niger transformant strain AOXEGFP-1 expressing a fusion gene, aox1-egfp, encoding AOX and enhanced green fluorescent protein (EGFP) to visually analyze the expression levels of aox1 without disruption of mycelia. In strain AOXEGFP-1, the localization of the fusion protein AOX-EGFP in the mitochondria was clearly confirmed because the sites of the green fluorescence by AOX-EGFP were in agreement with those of the red fluorescence of the mitochondria stained with MitoTracker Red CMXRos. When strain AOXEGFP-1 was cultivated with antimycin A, which inhibits the cytochrome pathway at the level of cytochrome bc(1) to cytochrome c and increases the expression level of aox1, EGFP fluorescence intensity increased with an increase in AOX activity measured as duroquinol oxidase activity. Moreover, EGFP fluorescence was detected in strain AOXEGFP-1 regardless of the glucose concentration in the cultivation media: for example, when cultivations were performed with 10, 30, 60 and 120 g/l glucose, EGFP fluorescence was usually detected in the mitochondria. These results indicate that aox1 was constitutively expressed regardless of the glucose concentration in A. niger.
    No preview · Article · Oct 2006 · Journal of Bioscience and Bioengineering