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Masahiro Ito

Faculty
Department of Life Sciences
Bio-Nano Electronics Research Center
Course of Life Sciences
PositionProfessor
Mail
HomepageURL
Birthday
Last Updated :2020/07/09

Researcher Profile and Settings

Association Memberships

  • The Biophysical Society of Japan
  • JAPAN SOCIETY FOR BIOSICENCE, BIOTECHNOLOGY, AND AGROCHEMISTRY
  • THE JAPANESE SOCIETY FOR EXTREMOPHILES
  • International society for Extremophiles
  • AMERICAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY
  • American society for Microbiology

Committee Memberships

  •   2015  - 現在, Applied and Environmental Microbiology, Editorial Board Member
  •   2013 01  - 現在, Japanese Society for Extremophiles, General affairs secretary
  •   2013 04  - 2020 03 , Toyo University, Center for Academic Research Promotion Deputy-Directors
  •   2008 08  - 2010 07 , Ministry of Education, Culture, Sports, Science and Technology (MEXT), Program officer

Academic & Professional Experience

  •   2009 04  - 現在, Toyo University, Factory of Life Sciences, Professor
  •   2001 04  - 2009 03 , Toyo University, Factory of Life Sciences, Associate professor
  •   1997 04  - 2001 03 , Toyo University, Factory of Life Sciences, Lecturer
  •   1994 04  - 1997 03 , Mount Sinai School of Medicine, Department of Biochemistry, postdoctoral researcher

Research Activities

Research Interests

    Bacillus, Bacillus pseudofirmus

Published Papers

  • A Factor Produced by Kaistia sp. 32K Accelerated the Motility of Methylobacterium sp. ME121., Yoshiaki Usui, Yuu Wakabayashi, Tetsu Shimizu, Yuhei O Tahara, Makoto Miyata, Akira Nakamura, Masahiro Ito, Biomolecules, Biomolecules, 10, (4) , 04 16 , Refereed
  • Draft Genome Sequence of Calcium-Dependent Novosphingobium sp. Strain TCA1, Isolated from a Hot Spring Containing a High Concentration of Calcium Ions., Shun Fujinami, Katsuya Satoh, Issay Narumi, Masahiro Ito, Microbiology resource announcements, Microbiology resource announcements, 9, (15) , 04 09 , Refereed
  • Tree of motility - A proposed history of motility systems in the tree of life., Makoto Miyata, Robert C Robinson, Taro Q P Uyeda, Yoshihiro Fukumori, Shun-Ichi Fukushima, Shin Haruta, Michio Homma, Kazuo Inaba, Masahiro Ito, Chikara Kaito, Kentaro Kato, Tsuyoshi Kenri, Yoshiaki Kinosita, Seiji Kojima, Tohru Minamino, Hiroyuki Mori, Shuichi Nakamura, Daisuke Nakane, Koji Nakayama, Masayoshi Nishiyama, Satoshi Shibata, Katsuya Shimabukuro, Masatada Tamakoshi, Azuma Taoka, Yosuke Tashiro, Isil Tulum, Hirofumi Wada, Ken-Ichi Wakabayashi, Genes to cells : devoted to molecular & cellular mechanisms, Genes to cells : devoted to molecular & cellular mechanisms, 25, (1) 6 - 21, 01 , Refereed
  • Editorial: For The Future of Alkaliphiles: 50th Anniversary Year Since the Rediscovery of Alkaliphiles by Dr. Koki Horikoshi., Masahiro Ito, Terry Ann Krulwich, Frontiers in microbiology, Frontiers in microbiology, 10, 2017 - 2017, Refereed
  • A Hydrophobic Small Protein, BpOF4_01690, Is Critical for Alkaliphily of Alkaliphilic Bacillus pseudofirmus OF4., Tetsuaki Takahashi, Terry A Krulwich, Masahiro Ito, Frontiers in microbiology, Frontiers in microbiology, 9, 1994 - 1994, Refereed
  • The Surface Layer Homology Domain-Containing Proteins of Alkaliphilic Bacillus pseudofirmus OF4 Play an Important Role in Alkaline Adaptation via Peptidoglycan Synthesis., Shun Fujinami, Masahiro Ito, Frontiers in microbiology, Frontiers in microbiology, 9, 810 - 810, Refereed
  • Load- and polysaccharide-dependent activation of the Na+-type MotPS stator in the Bacillus subtilis flagellar motor., Naoya Terahara, Yukina Noguchi, Shuichi Nakamura, Nobunori Kami-Ike, Masahiro Ito, Keiichi Namba, Tohru Minamino, Scientific reports, Scientific reports, 7, 46081 - 46081, 04 05 , Refereed
  • Ion Selectivity of the Flagellar Motors Derived from the Alkaliphilic Bacillus and Paenibacillus Species., Yuka Takahashi, Masahiro Ito, Methods in molecular biology (Clifton, N.J.), Methods in molecular biology (Clifton, N.J.), 1593, 297 - 303, Refereed
  • Mrp Antiporters Have Important Roles in Diverse Bacteria and Archaea., Masahiro Ito, Masato Morino, Terry A Krulwich, Frontiers in microbiology, Frontiers in microbiology, 8, 2325 - 2325, Refereed
  • Nonconventional cation-coupled flagellar motors derived from the alkaliphilic Bacillus and Paenibacillus species., Masahiro Ito, Yuka Takahashi, Extremophiles : life under extreme conditions, Extremophiles : life under extreme conditions, 21, (1) 3 - 14, 01 , Refereed
  • Differences in the phenotypic effects of mutations in homologous MrpA and MrpD subunits of the multi-subunit Mrp-type Na+/H+ antiporter, Masato Morino, Shinichiro Ogoda, Terry Ann Krulwich, Masahiro Ito, EXTREMOPHILES, EXTREMOPHILES, 21, (1) 51 - 64, 01 , Refereed
  • A novel type bacterial flagellar motor that can use divalent cations as a coupling ion, Riku Imazawa, Yuka Takahashi, Wataru Aoki, Motohiko Sano, Masahiro Ito, SCIENTIFIC REPORTS, SCIENTIFIC REPORTS, 6, e19773 - g0000197042, 01 , Refereed
  • Draft Genome Sequence of Methylobacterium sp. ME121, Isolated from Soil as a Mixed Single Colony with Kaistia sp. 32K., Shun Fujinami, Kiyoko Takeda-Yano, Takefumi Onodera, Katsuya Satoh, Tetsu Shimizu, Yuu Wakabayashi, Issay Narumi, Akira Nakamura, Masahiro Ito, Genome announcements, Genome announcements, 3, (5) , 09 03 , Refereed
  • Genome Sequence of the Deep-Sea Denitrifier Pseudomonas sp. Strain MT-1 isolated from the Mariana Trench, Fujinami S, Oikawa Y, Araki T, Shinmura Y, Midorikawa R, Ishizaka H, Kato C, Horikoshi K, Ito M, Tamegai H, Genome Announcements, Genome Announcements, 2, (6) , 12 , Refereed
  • Draft Genome Sequence of Bacillus alcalophilus AV1934, a Classic Alkaliphile Isolated from Human Feces in 1934., Oliver Attie, Anitha Jayaprakash, Hardik Shah, Ian T Paulsen, Masato Morino, Yuka Takahashi, Issay Narumi, Ravi Sachidanandam, Katsuya Satoh, Masahiro Ito, Terry A Krulwich, Genome announcements, Genome announcements, 2, (6) , 11 13 , Refereed
  • Ionic selectivity and thermal adaptations within the voltage-gated sodium channel family of alkaliphilic Bacillus, Paul G. DeCaen, Yuka Takahashi, Terry A. Krulwich, Masahiro Ito, David E. Clapham, ELIFE, ELIFE, 3, 11 , Refereed
  • Mutational analysis of charged residues in the cytoplasmic loops of MotA and MotP in the Bacillus subtilis flagellar motor, Yuka Takahashi, Masahiro Ito, JOURNAL OF BIOCHEMISTRY, JOURNAL OF BIOCHEMISTRY, 156, (4) 211 - 220, 10 , Refereed
  • Draft Genome Sequence of Calcium-Dependent Paenibacillus sp. Strain TCA20, Isolated from a Hot Spring Containing a High Concentration of Calcium Ions., Shun Fujinami, Kiyoko Takeda-Yano, Takefumi Onodera, Katsuya Satoh, Motohiko Sano, Yuka Takahashi, Issay Narumi, Masahiro Ito, Genome announcements, Genome announcements, 2, (5) , 09 04 , Refereed
  • Draft Genome Sequence of Potassium-Dependent Alkaliphilic Bacillus sp. Strain TS-2, Isolated from a Jumping Spider., Shun Fujinami, Kiyoko Takeda, Takefumi Onodera, Katsuya Satoh, Motohiko Sano, Issay Narumi, Masahiro Ito, Genome announcements, Genome announcements, 2, (3) , 05 22 , Refereed
  • Purification and Functional Reconstitution of a Seven-Subunit Mrp-Type Na+/H+ Antiporter, Masato Morino, Toshiharu Suzuki, Masahiro Ito, Terry Ann Krulwich, JOURNAL OF BACTERIOLOGY, JOURNAL OF BACTERIOLOGY, 196, (1) 28 - 35, 01 , Refereed
  • Suppressor mutants from MotB-D24E and MotS-D30E in the flagellar stator complex of Bacillus subtilis, Yuka Takahashi, Kotomi Koyama, Masahiro Ito, JOURNAL OF GENERAL AND APPLIED MICROBIOLOGY, JOURNAL OF GENERAL AND APPLIED MICROBIOLOGY, 60, (4) 131 - 139, Refereed
  • Draft Genome Sequence of Sodium-Independent Alkaliphilic Microbacterium sp. Strain TS-1., Shun Fujinami, Kiyoko Takeda, Takefumi Onodera, Katsuya Satoh, Motohiko Sano, Issay Narumi, Masahiro Ito, Genome announcements, Genome announcements, 1, (6) , 12 19 , Refereed
  • Functional expression of the multi-subunit type calcium/proton antiporter from Thermomicrobium roseum, Masato Morino, Masahiro Ito, FEMS MICROBIOLOGY LETTERS, FEMS MICROBIOLOGY LETTERS, 335, (1) 26 - 30, 10 , Refereed
  • Characterization and purification of the multi subunit type Na+/H+ antiporter from alkaliphilic Bacillus pseudofirmus OF4, Masato Morino, Toshiharu Suzuki, Masahiro Ito, BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS, BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS, 1817, S36 - S36, 10 , Refereed
  • A Bacillus Flagellar Motor That Can Use Both Na+ and K+ as a Coupling Ion Is Converted by a Single Mutation to Use Only Na+, Naoya Terahara, Motohiko Sano, Masahiro Ito, PLOS ONE, PLOS ONE, 7, (9) , 09 , Refereed
  • Genome of alkaliphilic Bacillus pseudofirmus OF4 reveals adaptations that support the ability to grow in an external pH range from 7.5 to 11.4, Benjamin Janto, Azad Ahmed, Masahiro Ito, Jun Liu, David B. Hicks, Sarah Pagni, Oliver J. Fackelmayer, Terry-Ann Smith, Joshua Earl, Liam D. H. Elbourne, Karl Hassan, Ian T. Paulsen, Anne-Brit Kolsto, Nicolas J. Tourasse, Garth D. Ehrlich, Robert Boissy, D. Mack Ivey, Gang Li, Yanfen Xue, Yanhe Ma, Fen Z. Hu, Terry A. Krulwich, ENVIRONMENTAL MICROBIOLOGY, ENVIRONMENTAL MICROBIOLOGY, 13, (12) 3289 - 3309, 12 , Refereed
  • The relationship between a coiled morphology and Mbl in alkaliphilic Bacillus halodurans C-125 at neutral pH values, Shun Fujinami, Takako Sato, Masahiro Ito, EXTREMOPHILES, EXTREMOPHILES, 15, (5) 587 - 596, 09 , Refereed
  • Single Site Mutations in the Hetero-oligomeric Mrp Antiporter from Alkaliphilic Bacillus pseudofirmus OF4 That Affect Na+/H+ Antiport Activity, Sodium Exclusion, Individual Mrp Protein Levels, or Mrp Complex Formation, Masato Morino, Shinsuke Natsui, Tomohiro Ono, Talia H. Swartz, Terry A. Krulwich, Masahiro Ito, JOURNAL OF BIOLOGICAL CHEMISTRY, JOURNAL OF BIOLOGICAL CHEMISTRY, 285, (40) 30942 - 30950, 10 , Refereed
  • Motility and chemotaxis in alkaliphilic Bacillus species, Shun Fujinami, Naoya Terahara, Terry Ann Krulwich, Masahiro Ito, FUTURE MICROBIOLOGY, FUTURE MICROBIOLOGY, 4, (9) 1137 - 1149, 11 , Refereed
  • Cation/proton antiporter complements of bacteria: why so large and diverse?, Terry A. Krulwich, David B. Hicks, Masahiro Ito, MOLECULAR MICROBIOLOGY, MOLECULAR MICROBIOLOGY, 74, (2) 257 - 260, 10 , Refereed
  • Characterization of Bacillus subtilis YfkE (ChaA): a calcium-specific Ca2+/H+ antiporter of the CaCA family, Makoto Fujisawa, Yuko Wada, Takahiro Tsuchiya, Masahiro Ito, ARCHIVES OF MICROBIOLOGY, ARCHIVES OF MICROBIOLOGY, 191, (8) 649 - 657, 08 , Refereed
  • Mutations alter the sodium versus proton use of a Bacillus clausii flagellar motor and confer dual ion use on Bacillus subtilis motors, Naoya Terahara, Terry A. Krulwich, Masahiro Ito, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 105, (38) 14359 - 14364, 09 , Refereed
  • Single gene deletions of mrpA to mrpG and mrpE point mutations affect activity of the Mrp Na+/H+ antiporter of alkaliphilic Bacillus and formation of hetero-monieric Mrp complexes, Masato Morino, Shinsuke Natsui, Talia H. Swartz, Terry A. Krulwich, Masahiro Ito, JOURNAL OF BACTERIOLOGY, JOURNAL OF BACTERIOLOGY, 190, (12) 4162 - 4172, 06 , Refereed
  • The voltage-gated Na+ channel NaVBP co-localizes with methyl-accepting chemotaxis protein at cell poles of alkaliphilic Bacillus pseudofirmus OF4, Shun Fujinami, Takako Sato, James S. Trimmer, Benjamin W. Spiller, David E. Clapham, Terry A. Krulwich, Ikuro Kawagish, Masahiro Ito, MICROBIOLOGY-SGM, MICROBIOLOGY-SGM, 153, 4027 - 4038, 12 , Refereed
  • Three two-component transporters with channel-like properties have monovalent cation/proton antiport activity, Makoto Fujisawa, Masahiro Ito, Terry A. Krulwich, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 104, (33) 13289 - 13294, 08 , Refereed
  • Catalytic properties of Staphylococcus aureus and Bacillus members of the secondary cation/proton antiporter-3 (Mrp) family are revealed by an optimized assay in an Escherichia coli host, Talia H. Swartz, Masahiro Ito, Takayuki Ohira, Shinsuke Natsui, David B. Hicks, Terry A. Krulwich, JOURNAL OF BACTERIOLOGY, JOURNAL OF BACTERIOLOGY, 189, (8) 3081 - 3090, 04 , Refereed
  • Na+ and flagella-dependent swimming of alkaliphilic Bacillus pseudofirmus OF4: a basis for poor motility at low pH and enhancement in viscous media in an "up-motile" variant, Shun Fujinami, Naoya Terahara, Sunmi Lee, Masahiro Ito, ARCHIVES OF MICROBIOLOGY, ARCHIVES OF MICROBIOLOGY, 187, (3) 239 - 247, 03 , Refereed
  • An intergenic stem-loop mutation in the Bacillus subtilis ccpA-motPS operon increases motPS transcription and the MotPS contribution to motility, N Terahara, M Fujisawa, B Powers, TM Henkin, TA Krulwich, M Ito, JOURNAL OF BACTERIOLOGY, JOURNAL OF BACTERIOLOGY, 188, (7) 2701 - 2705, 04 , Refereed
  • Activity profile of the NhaD-Type Na+(Li+)/H+ antiporter from the soda lake haloalkaliphile Alkalimonas amylolytica is adaptive for the extreme environment, J Liu, YF Xue, QH Wang, Y Wei, TH Swartz, DB Hicks, M Ito, YH Ma, TA Krulwich, JOURNAL OF BACTERIOLOGY, JOURNAL OF BACTERIOLOGY, 187, (22) 7589 - 7595, 11 , Refereed
  • The Mrp system: a giant among monovalent cation/proton antiporters?, TH Swartz, S Ikewada, O Ishikawa, M Ito, TA Krulwich, EXTREMOPHILES, EXTREMOPHILES, 9, (5) 345 - 354, 10 , Refereed
  • NhaK, a novel monovalent cation/H+ antiporter of Bacillus subtilis, M Fujisawa, A Kusumoto, Y Wada, T Tsuchiya, M Ito, ARCHIVES OF MICROBIOLOGY, ARCHIVES OF MICROBIOLOGY, 183, (6) 411 - 420, 09 , Refereed
  • Properties of motility in Bacillus subtilis powered by the H+-coupled MotAB flagellar stator, Na+-coupled MotPS or hybrid stators MotAS or MotPB, M Ito, N Terahara, S Fujinami, TA Krulwich, JOURNAL OF MOLECULAR BIOLOGY, JOURNAL OF MOLECULAR BIOLOGY, 352, (2) 396 - 408, 09 , Refereed
  • The mrp Na+/H+ antiporter increases the activity of the malate: Quinone oxidoreductase of an Escherichia coli respiratory mutant, TH Swartz, M Ito, DB Hicks, M Nuqui, AA Guffanti, TA Krulwich, JOURNAL OF BACTERIOLOGY, JOURNAL OF BACTERIOLOGY, 187, (1) 388 - 391, 01 , Refereed
  • MotPS is the stator-force generator for motility of alkaliphilic Bacillus, and its homologue is a second functional Mot in Bacillus subtilis, M Ito, DB Hicks, TM Henkin, AA Guffanti, BD Powers, L Zvi, K Uematsu, TA Krulwich, MOLECULAR MICROBIOLOGY, MOLECULAR MICROBIOLOGY, 53, (4) 1035 - 1049, 08 , Refereed
  • The voltage-gated Na+ channel NavBP has a role in motility, chemotaxis, and pH homeostasis of an alkaliphilic Bacillus, M Ito, HX Xu, AA Guffanti, Y Wei, L Zvi, DE Clapham, TA Krulwich, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 101, (29) 10566 - 10571, 07 , Refereed
  • Modulation of the K+ efflux activity of Bacillus subtilis YhaU by YhaT and the C-terminal region of YhaS, M Fujisawa, Y Wada, M Ito, FEMS MICROBIOLOGY LETTERS, FEMS MICROBIOLOGY LETTERS, 231, (2) 211 - 217, 02 , Refereed
  • Mutational loss of a K+ and NH4+ transporter affects the growth and endospore formation of alkaliphilic Bacillus pseudofirmus OF4, Y Wei, TW Southworth, H Kloster, M Ito, AA Guffanti, A Moir, TA Krulwich, JOURNAL OF BACTERIOLOGY, JOURNAL OF BACTERIOLOGY, 185, (17) 5133 - 5147, 09 , Refereed
  • Decrease in cytoplasmic pH-Homeostastatic activity of the alkaliphile Bacillus Lentus C-125 by a cell wall defect, M Ito, R Aono, BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, 66, (1) 218 - 220, 01 , Refereed
  • Bacillus subtilis YqkI is a novel malic/Na(+)-lactate antiporter that enhances growth on malate at low protonmotive force, Y Wei, AA Guffanti, M Ito, TA Krulwich, JOURNAL OF BIOLOGICAL CHEMISTRY, JOURNAL OF BIOLOGICAL CHEMISTRY, 275, (39) 30287 - 30292, 09 , Refereed
  • Two types of Bacillus subtilis tetA(L) deletion strains reveal the physiological importance of TetA(L) in K+ acquisition as well as in Na+, alkali, and tetracycline resistance, W Wang, AA Guffanti, Y Wei, M Ito, TA Krulwich, JOURNAL OF BACTERIOLOGY, JOURNAL OF BACTERIOLOGY, 182, (8) 2088 - 2095, 04 , Refereed

Misc

  • 世界初:2価陽イオンで駆動するべん毛モーターCa2+やMg2+でもべん毛は回転する, Masahiro Ito, kagaku to seibutsu, 55, (4) 240 - 241,   2017 03 , 査読有り, 招待有り
  • 13.好アルカリ性細菌の高アルカリ性環境適応機構, Yuka Takahashi, Masahiro Ito, Nihon nyusankin gakkai shi, 25, (3) 177 - 177,   2014 11 , 査読有り, 招待有り
  • The charged amino acid residues of two different stators of the flagellar motor in Bacillus subtilis are important for motility, Yuka Takahashi, Masahiro Ito, BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS, 1817,   2012 10
  • An analysis of amino acid residues which affect the structure of the ion flux pathway of the flagellar stator complex from Bacillus subtilis, Kotomi Koyama, Masahiro Ito, BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS, 1817,   2012 10
  • Alkaliphilic Microorganisms : Lessons from Their Adaptations(Papers presented at the Seminar, "Biological mechanism of stress perception"), ITO Masahiro, Cryobiology and cryotechnology, 57, (1) 25 - 32,   2011 04 15 , Alkaliphiles, which are capable of growth in an extremely alkaline environment, serve as a model system to understand the physiological mechanisms allowing microbial growth under extreme environmental conditions. The internal pH of alkaliphiles is kept 2 units lower than the external pH 10 or higher. In alkaliphilic Bacillus, Na^+-dependent pH homeostasis involves the Na^+/H^+ antiport activities as well as Na^+ re-entry routes. A predominant role was evident for the NaChBac (voltage-dependent) Na channel of alkaliphilic B. pseudofirmus OF4 at sub-optimal [Na^+]. NaChBac mutants exhibit a s...
  • 私達の研究(82)細菌のべん毛モーターの新展開~自然界のハイブリッドモーター~, 寺原直矢, 伊藤政博, 化学療法の領域, 26, (1) 90 - 98,   2009 12 25
  • Single Stator Complex of Bacterial Flagellar Motor Can Be Use Both H^+ and Na^+ for Stator Force Generator in Alkaliphilic Bacillus and Confer Dual Ion Use on Bacillus subtilis Motors, ITO Masahiro, TERAHARA Naoya, KAGAKU TO SEIBUTSU, 47, (7) 473 - 479,   2009 07 01
  • Molecular basis and swimming properties of a natural dual hybrid flagellar motor of Bacillus subtilis, TERAHARA Naoya, ITO Masahiro, Bioscience & industry, 66, (7) 366 - 368,   2008 07 01
  • Channel-like two-component transporters that have monovalent-cation/proton antiport activity, FUJISAWA Makoto, ITO Masahiro, Bioscience & industry, 66, (6) 300 - 302,   2008 06 01
  • The Physiological Role of Two Sodium Channels MotPS and Na_vBP of Alkaliphilic Bacillus, ITOH Masahiro, Biophysics, 46, (1) 20 - 25,   2006 01 25 , In alkaliphilic Bacillus, Na^+-dependent pH homeostasis involves antiport activities as well as Na^+ re-entry routes. MotPS that are homologous to MotAB are required for the Na^+-dependent motility of alkaliphilic B. pseudofirmus OF4. Purified and reconstituted MotPS support amiloride analogue-sensitive Na^+ flux. Mutants lacking functional MotPS display no deficit in pH homeostasis in pH shift experiments conducted with sub-optimal added [Na^+] in the absence of solutes whose uptake is coupled to Na^+ re-entry. By contrast, a role was evident for the recently described NaChBac (voltage-dep...
  • pH Homeostasis and ATP synthesis: studies of two processes that necessitate inward proton translocation in extremely alkaliphilic Bacillus species, TA Krulwich, M Ito, DB Hicks, R Gilmour, AA Guffanti, EXTREMOPHILES, 2, (3) 217 - 222,   1998 08 , Alkaliphilic Bacillus species that are isolated from nonmarine, moderate salt, and moderate temperature environments offer the opportunity to explore strategies that have developed for solving the energetic challenges of aerobic growth at pH values between 10 and 11. Such bacteria share many structural, metabolic, genomic, and regulatory features with nonextremophilic species such as Bacillus subtilis. Comparative studies can therefore illuminate the specific features of gene organization and special features of gene products that are homologs of those found in non-extremophiles, and potentially identify novel gene products of importance in alkaliphily. We have focused our studies on the facultative alkaliphile Bacillus firmus OF4, which is routinely grown on malate-containing medium at either pH 7.5 or 10.5. Current work is directed toward clarification of the characteristics and energetics of membrane-associated proteins that must catalyze inward proton movements. One group of such proteins are the Na+/H+ antiporters that enable cells to adapt to a sudden upward shift in pH and to maintain a cytoplasmic pH that is 2-2.3 units below the external pH in the most alkaline range of pH for growth. Another is the proton-translocating ATP synthase that catalyzes robust production of ATP under conditions in which the external proton concentration and the bulk chemiosmotic driving force are low. Three gene loci that are candidates for Na+/H+ antiporter encoding genes with roles in Na+-dependent pH homeostasis have been identified. All of them have homologs in B. subtilis, in which pH homeostasis can be carried out with either K+ or Na+. The physiological importance of one of the B. firmus OF4 loci, nhaC, has been studied by targeted gene disruption, and the same approach is being extended to the others. The ntp genes that encode the alkaliphile's F1FO-ATP synthase are found to have interesting motifs in areas of putative importance for proton translocation. As an initial step in studies that will probe the importance and possible roles of these motifs, the entire atp operon from B. firmus OF4 has been cloned and functionally expressed in an Escherichia coli mutant that has a full deletion of its ntp genes. The transformant does not exhibit growth on succinate, but shows reproducible, modest increases in the aerobic growth yields on glucose as well as membrane ATPase activity that exhibits characteristics of the alkaliphile enzyme.

Awards & Honors

  •   2018 12 , Japanese Society for Extremophiles, Excellent Poster Award
  •   2016 12 , The 1st international Conference on Applied Microbiology in Vietnam, Young Scientist Poster Award (1st), Elucidation ion selectivity and identification of ion transport subunits in the Mrp type antiporter
  •   2015 11 , The 16th Annual Meeting of the Japanese society for Extremophiles, Poster award, A functional analysis of stator complex of flagellar motor from Bacillus trypoxylicola
  •   2014 12 , The 15th Annual Meeting of the Japanese society for Extremophiles, Poster award, Elucidation of the differences in Na+ affinity in a neutral pH environment of the Na+-driven stator MotPS in alkaliphilic Bacillus pseudofirmus OF4 and Bacillus subtilis
  •   2014 11 , The 15th Annual Meeting of the Japanese society for Extremophiles, Poster award, Identification for a factor affecting of stimulation of motility in Methylobacterium sp. 121
  •   2014 09 , International Congress on Extremophiles 2014, ISE Young Scientist Poster Award, The clarification of the differences between alkaliphilic and neutralophilic Bacillus influx control of Na+ near neutral pH in the Na+-driven flagellar motor stator MotPS
  •   2013 03 , Blue Earth 2013 (JAMSTEC), Young Scientist Poster Award, Analytical results of microbiological diversity in the seismogenic zone (Japan trench) sediment at 3 months and 17 months after Tohoku Region Pacific Offshore Earthquake occurred
  •   2012 11 , The 2012 Annual Meeting of the Kanto Branch of the Japan Society for Bioscience, Biotechnology, and Agrochemistry, Poster award, Elucidation of rotation mechanism of hybrid biomotor that can utilize two types of coupling ions
  •   2012 06 , Toyo University, Inoue Enryo Prize, Research on Hybrid Bacterial Flagellar Motor
  •   2011 11 , The 12th Annual Meeting of the Japanese society for Extremophiles, Poster award, A novel K+-stimulated flagellar motor from alkaliphilic Bacillus alcalophilus.
  •   2011 10 , The 2011 Annual Meeting of the Kanto Branch of the Japan Society for Bioscience, Biotechnology, and Agrochemistry, Poster award, Identification of amino acid residues in the flagellar stator involved in the reduction of motility under the neutral environment of the alkalophilic Bacillus pseudofirmus OF4
  •   2011 03 , the Japan Society for the Promotion of Science, JSPS Prize, Properties of Bacterial Flagellar Motor Powered by Hybrid Stators
  •   2009 11 , The 10th Annual Meeting of the Japanese society for Extremophiles, Poster award, Identification and characterization of functional residues in a Multi-subunit type Na+/H+ antiporter Mrp complex from alkaliphilic Bacillus pseudofirmus OF4.
  •   2009 10 , The 10th Annual Meeting of the Japanese society for Extremophiles, Poster award, Identification and analysis of amino acid residues important for the rotation mechanism of flagellar stator MotAB, MotPS of Bacillus subtilis
  •   2008 11 , The 9th Annual Meeting of the Japanese society for Extremophiles, Poster award, A conversion of the coupling ion specificity of stators in a Bacillus flagellar motor
  •   2008 06 , The 3rd Japan transporter research association, Outstanding performance award(Oral presentation), A flagellarstator MotAB from alkaliphilic Bacillus clausii can utilize two types of ions as coupling ions
  •   2007 11 , Kanto Branch meeting of the Japan Society for Bioscience, Biotechnology, and Agrochemistry, Young Scientist Award (oral presentation), Bacillus subtilis flagellar motor is a hybrid motor that can utilize two kinds of energy
  •   2007 11 , The 8th Annual Meeting of the Japanese society for Extremophiles, Poster award, The visualization of the voltage-gated Na+ channel of Alkaliphilic Bacillus pseudofirmus OF4 by using fluorescent protein fusion.
  •   2005 11 , the Japan Society for Extremophiles, Young Scientist Award
  •   2004 11 , The 5th Annual Meeting of the Japanese society for Extremophiles, Poster award
  •   2002 09 , International Society for Extremophiles (ISE), ISE Award

Research Grants & Projects

  • Elucidation of structure-function of unique bacterial flagellar stator complex from Bacillus spp., Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(基盤研究(B)), At first, we identified that the flagellar motor of B. subtilis was a hybrid motor and it rotated by using both ion motive forces, H+ and Na+, by a single molecular mechanism. Next, the critical charged amino acid residues between the second and third transmembrane cytoplasmic loop region in MotA and MotP subunits of B. subtilis were identified by using site-directed mutagenesis. Moreover, we identified a novel type flagellar motor from alkaliphilic Bacillus alcalophilus which stimulates swimming speed under elevated K+ or Rb+ concentrations. This is the first report that describes aflagellar motor that can use both K+ and Rb+ as coupling ions.
  • The Voltage-Gated Na+ Channel Co-localizes with Methyl-Accepting Chemotaxis Proteins ofAlkaliphile at a Cell Pole, Ministry of Education, Culture, Sports, Science and Technology, Grants-in-Aid for Scientific Research(基盤研究(C)), The bacterial ion channels are useful for the structural analysis of the eukaryotic ion channels. The elucidation of physiologic functions and effecter proteins of the bacterial ion channels is important in research of the ion channels. NavBP is the member of the bacterial voltage-gated Na+ channel superfamily that is found in alkaliphilic Bacillus pseudofirmus OF4. NavBP has recently been shown to have a role in pH homeostasis, motility and chemotaxis. The chemotaxis phenotype of NavBP deletion mutant was particularly striking in that the response of the mutants to chemoattractants was inverted compared to the wild-type strain. Therefore, we have studied to elucidate the relation of the deficit of Na channel and the abnormalities in chemotaxis. We have already reported the following things. First, in the wild-type strain, colocalization of NavBP and the putative chemotaxis receptor McpX was observed at cell pole by immuno fluorescent microscopy (IFM). Second, in the NavBP deletion mutant, although the expression level of McpX did not change mostly, but the localization of that was decreased. Then, in order to observe cellullar localization of NavBP in a live cell, the plasmid which express the NavBP-CFP fusion protein was constructed, the transformation was carried out to NavBP deletion mutant. As a result, polar localization of functional NavBP-CFP was observed. The polar localization of NavBP in alkaliphilic Bacillus pseudofirmus OF4 was strongly suggested. In order for a chemotaxis receptor to function, it is necessary to localized at cell pole. The results suggest interactions between NavBP and McpX that affect their co-localization at cell pole. The inverse chemotaxis phenotype of NavBP deletion mutants may result in part from delocalization of McpX.