Yamasaki Hideo

写真a

Title

Professor

Researcher Number(JSPS Kakenhi)

40222369

Homepage URL

http://www.biology.sci.u-ryukyu.ac.jp/?lang=en

Current Affiliation Organization 【 display / non-display

  • Concurrently   University of the Ryukyus   Graduate School of Engineering and Science   Chemistry, Biology and Marine Science   Professor  

  • Concurrently   University of the Ryukyus   Graduate School of Engineering and Science   Marine and Environmental Sciences   Professor  

  • Duty   University of the Ryukyus   Faculty of Science   Chemistry, Biology and Marine Science   Professor  

University 【 display / non-display

  • 1980.04
    -
    1985.03

    Kyushu University   Faculty of Science   Department of Biology   Graduated

Graduate School 【 display / non-display

  • 1985.04
    -
    1987.03

    Kyushu University  Graduate School, Division of Natural Science  Department of Biology  Master's Course  Completed

  • 1987.04
    -
    1991.11

    Kyushu University  Graduate School, Division of Natural Science  Department of Biology  Doctor's Course  Completed

Study abroad experiences 【 display / non-display

  • 1997.04
    -
    1998.03

    Australian National Unveristy, Research School for Biological Sciences  

Academic degree 【 display / non-display

  • Kyushu University -  Ph.D.

External Career 【 display / non-display

  • 1990.04
    -
    1992.03

    JSPS post doctoral fellow  

  • 1992.04
    -
    1996.06

    University of the Ryukyus, Faculty of Science, Department of Biology, Assistant Professor  

  • 1996.07
    -
    2000.06

    University of the Ryukyus, Faculty of Science, Department of Chemisity, Biology and Marine Sciences, Laboratory of Cell and Fucntional Biology, Associate Professor  

  • 1997.04
    -
    1998.03

    Australian National University, Research School of Biological Sciences Visiting Fellow  

  • 2000.07
    -
    2005.07

    University of the Ryukyus, Center of Molecular Biosciences, Professor  

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Research Interests 【 display / non-display

  • 光合成

  • 環境生物学

  • Stress Physiology

  • Environmental Biology

  • Biochemistry

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Research Areas 【 display / non-display

  • Environmental Science/Agriculture Science / Landscape science

  • Life Science / Plant molecular biology and physiology

  • Environmental Science/Agriculture Science / Environmental load reduction and remediation

  • Environmental Science/Agriculture Science / Crop production science

  • Life Science / Nutrition science and health science

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Research Theme 【 display / non-display

  • Biology and Biochemistry of Reactive Oxygen, Nitrogen, Sulfur species

  • Antioxidant system in Plants

  • Bioremedation in Subtropical Environment

  • Study on the mechanisms of coral bleaching

Published Papers 【 display / non-display

  • Pleiotropic Functions of Nitric Oxide Produced by Ascorbate for the Prevention and Mitigation of COVID-19: A Revaluation of Pauling's Vitamin C Therapy.

    Yamasaki H, Imai H, Tanaka A, Otaki JM

    Microorganisms ( Microorganisms )  11 ( 2 ) 397   2023.02 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

     View Summary

    Linus Pauling, who was awarded the Nobel Prize in Chemistry, suggested that a high dose of vitamin C (L-ascorbic acid) might work as a prevention or treatment for the common cold. Vitamin C therapy was tested in clinical trials, but clear evidence was not found at that time. Although Pauling’s proposal has been strongly criticized for a long time, vitamin C therapy has continued to be tested as a treatment for a variety of diseases, including coronavirus infectious disease 2019 (COVID-19). The pathogen of COVID-19, SARS-CoV-2, belongs to the β-coronavirus lineage, which includes human coronavirus, severe acute respiratory syndrome (SARS), and Middle East respiratory syndrome (MERS). This review intends to shed new light on vitamin C antiviral activity that may prevent SARS-CoV-2 infection through the chemical production of nitric oxide (NO). NO is a gaseous free radical that is largely produced by the enzyme NO synthase (NOS) in cells. NO produced by upper epidermal cells contributes to the inactivation of viruses and bacteria contained in air or aerosols. In addition to enzymatic production, NO can be gener-ated by the chemical reduction of inorganic nitrite (NO2−), an alternative mechanism for NO production in living organisms. Dietary vitamin C, largely contained in fruits and vegetables, can reduce the nitrite in saliva to produce NO in the oral cavity when chewing foods. In the stomach, salivary nitrite can also be reduced to NO by vitamin C secreted from the epidermal cells of the stomach. The strong acidic pH of gastric juice facilitates the chemical reduction of salivary nitrite to produce NO. Vitamin C contributes in multiple ways to the host innate immune system as a first-line defense mechanism against pathogens. Highlighting chemical NO production by vitamin C, we suggest that controversies on the therapeutic effects of vitamin C in previous clinical trials may partly be due to less appreciation of the pleiotropic functions of vitamin C as a universal bioreductant.

  • Phytochemical Antioxidants: Past, Present and Future

    Yasuko Sakihama, Hideo Yamasaki

    Antioxidants - Benefits, Sources, Mechanisms of Action ( IntechOpen )    2021.01 [ Peer Review Accepted ]

    Type of publication: Research paper (other science council materials etc.)

     View Summary

    Most diseases that are difficult to prevent and cure are “syndromes" that are governed by multiple components with complicated interactions. Whatever the cause of such diseases, overproduction of harmful reactive oxygen species (ROS) can often be observed in progression of the disease. Under such conditions, the cells may be challenged by “oxidative stress" due to excessively generated oxidants. Antioxidants can be defined as chemical compounds that scavenge ROS or free radicals over-produced in the cells under oxidative stress conditions. The plant pigments flavonoids and betalains, rich in fruits and vegetables, are reactive not only with ROS but also with reactive nitrogen species (RNS) and possibly with reactive sulfur species (RSS). Here, we provide an overview of updates on the antioxidative functions of the plant pigments along with some prospects for future research on phytochemical antioxidants.

  • Blood nitrate and nitrite modulating nitric oxide bioavailability: Potential therapeutic functions in COVID-19.

    Yamasaki H

    Nitric oxide : biology and chemistry ( Elsevier BV )  103   29 - 30   2020.10 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

     View Summary

    Most outcomes of COVID-19 are associated with dysfunction of the vascular system, particularly in the lung. Inhalation of nitric oxide (NO) gas is currently being investigated as a treatment for patients with moderate to severe COVID-19. In addition to the expected vasodilation effect, it has been also suggested that NO potentially prevents infection by SARS-CoV-2. Since NO is an unstable radical molecule that is easily oxidized by multiple mechanisms in the human body, it is practically difficult to control its concentration at lesions that need NO. Inorganic nitrate and/or nitrite are known as precursors of NO that can be produced through chemical as well enzymatic reduction. It appears that this NO synthase (NOS)-independent mechanism has been overlooked in the current developing of clinical treatments. Here, I suggest the missing link between nitrate and COVID-19 in terms of hypoxic NO generation.

  • D-Cysteine-Induced Rapid Root Abscission in the Water Fern Azolla Pinnata: Implications for the Linkage between D-Amino Acid and Reactive Sulfur Species (RSS) in Plant Environmental Responses.

    Yamasaki H, Ogura MP, Kingjoe KA, Cohen MF

    Antioxidants ( Antioxidants )  8 ( 9 )   2019.09 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

     View Summary

    Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) have been proposed as universal signaling molecules in plant stress responses. There are a growing number of studies suggesting that hydrogen sulfide (H#D2#DRS) or Reactive Sulfur Species (RSS) are also involved in plant abiotic as well as biotic stress responses. However, it is still a matter of debate as to how plants utilize those RSS in their signaling cascades. Here, we demonstrate that d-cysteine is a novel candidate for bridging our gap in understanding. In the genus of the tiny water-floating fern #IAzolla#IR, a rapid root abscission occurs in response to a wide variety of environmental stimuli as well as chemical inducers. We tested five H#D2#DRS chemical donors, Na#D2#DRS, GYY4137, 5a, 8l, and 8o, and found that 5a showed a significant abscission activity. Root abscission also occurred with the polysulfides Na#D2#DRS#D2#DR, Na#D2#DRS#D3#DR, and Na#D2#DRS#D4#DR. Rapid root abscission comparable to other known chemical inducers was observed in the presence of d-cysteine, whereasLl-cysteine showed no effect. We suggest that D-cysteine is a physiologically relevant substrate to induce root abscission in the water fern #IAzolla#IR.

  • Dynamics of nitrite content in fresh spinach leaves: evidence for nitrite formation caused by microbial nitrate reductase activity

    Naoko S Watanabe, Hideo Yamasaki

    Journal of Nutrition & Food Sciences   7   1 - 7   2017.02 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

     View Summary

    Nitrite (NO#D2#DR#U-#UR) contained in dietary foods has long been recognized for its toxicity as the causative agent of methemoglobinemia and also as a source of mutagenic nitrosamines. Because of these potential toxicities, nitrite as well as nitrate contained in foods and drinks are strictly limited by regulations in many countries. Recent studies have offered us to update our recognition of nitrite; nitrite is an important precursor for nitric oxide (NO) that is required for fundamental physiological activities including vasorelaxation. Although it is well established that green vegetables contain high amounts of nitrate, there has been controversy regarding the source of nitrite accumulation in fresh green vegetables. In this study, we investigated the dynamics of nitrite and nitrate contents in spinach leaf extracts to verify the mechanisms of nitrite formation. The time course of nitrite production in leaf extracts showed a reciprocal relationship with nitrate degradation, suggesting a conversion from nitrate to nitrite. The reaction strongly depended on temperature and it was suppressed at a low temperature. Sodium tungstate, a nitrate reductase enzyme inhibitor, was effective to suppress the conversion. Pre-sterilization by autoclaving or filter sterilization completely prevented the formation of nitrite as well as degradation of nitrate. We suggest that previous reports of nitrite accumulation can be attributed to microbial nitrate reductase activities that occur during the degradation spinach leaves.

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Books 【 display / non-display

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Other Papers 【 display / non-display

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Presentations 【 display / non-display

  • Escaping troubled waters: An animal-like stimulus-response behavior in a model plant

    Michael F Cohen, Hideo Yamasaki

    The 12th International NO Conference  2022.10  -  2022.11 

  • Yin-Yang of bioactive gaseous molecules: Bridging the gap between Western science and traditional Eastern philosophies

    Hideo Yamasaki

    Special Lecture  (Chinese Culture University, Taiwan)  2018.05  -  2018.05 

  • ONS biology for bridging the gaps

    Hideo Yamasaki

    9th International Conference on the Biology, Chemistry, and Therapeutic Applications of Nitric Oxide  (Sendai International Center, Sendai, Japan)  2016.05  -  2016.05 

  • Nitric oxide research in living organisms

    Hideo Yamasaki

    Special Lecture  (Chinese Culture University, Taiwan)  2014.11  -  2014.11 

  • Nitrite as a crossroad of multidisciplines: its past, present and future

    Hideo Yamasaki

    The International Symposium on Food, Nutrition and Vascular Function 2013  ( Tokushima, Japan)  2013.12  -  2013.12 

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Social Activity 【 display / non-display

  • 2015.07
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    2017.03

  • 2015.07
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    2017.03

  • 2014.11
     
     

  • 2014.08
     
     

  • 2012.09
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    2015.03

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Media Coverage 【 display / non-display

  • 沖縄県自然環境再生指針検討委員会 委員長

    沖縄県  2014.7

Academic Activities 【 display / non-display

  • 日本NO学会 

    2016.6
     
     

  • 沖縄科学技術大学院大学(OIST) 

    2014.11
     
     

  • 沖縄県 

    2014.8
     
     

  • 日本植物学会 

    2013.1
    -
    2018.12

    種別: Academic society, research group, etc. 

  • 沖縄県産業振興公社 

    2012.5
    -
    2013.3

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