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Takatsuji Y, Morimoto M, Nakatsuru Y, Haruyama T. Anodized Zn electrode for formate selectivity during the electrochemical reduction of CO2 at low applied potential. Electrochem commun 2022. [DOI: 10.1016/j.elecom.2022.107281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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2
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Okita K, Yamasaki R, Nakamura Y, Sakakura T, Kawano A, Takatsuji Y, Haruyama T, Yoshioka Y, Ariyoshi W. Quick and environmentally friendly sterilization process of dental instruments by radical vapor reactor. Process Biochem 2022. [DOI: 10.1016/j.procbio.2021.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Tsuchida Y, Murakami N, Sakakura T, Takatsuji Y, Haruyama T. Drastically Increase in Atomic Nitrogen Production Depending on the Dielectric Constant of Beads Filled in the Discharge Space. ACS Omega 2021; 6:29759-29764. [PMID: 34778648 PMCID: PMC8582067 DOI: 10.1021/acsomega.1c04201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/11/2021] [Indexed: 06/13/2023]
Abstract
Nitrogen activation, especially dissociation (production of atomic nitrogen), is a key step for efficient nitrogen fixation, such as nitrogen reduction to produce ammonia. Nitrogen reduction reactions using water as a direct hydrogen source have been studied by many researchers as a green ammonia process. We studied the reaction mechanism and found that the nitrogen reduction could be significantly improved via efficient production of atomic nitrogen through electric discharge. In the present study, we focused on packed-bed dielectric barrier discharge (PbDBD) using dielectric beads as the packing material. The experimental results showed that more atomic nitrogen was produced in the nitrogen activation by the discharge in which the discharge space was filled with the dielectric beads than in the nitrogen activation by the discharge without using the dielectric beads. Then, it was clarified that the amount of atomic nitrogen increased as the dielectric constant of the beads to be filled increased, and the amount of atomic nitrogen produced increased up to 13.48 times. Based on the results, we attempted ammonia synthesis using water as a direct hydrogen source with the efficiently generated atomic nitrogen. When the atomic nitrogen gas generated by the PbDBD was sprayed onto the surface of the water phase and subsequently reacted as a plasma/liquid interfacial reaction, the nitrogen fixation rate increased by 7.26-fold compared to that when using the discharge without dielectric beads, and the ammonia production selectivity increased to 83.7%.
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Affiliation(s)
- Yuto Tsuchida
- Division
of Functional Interface Engineering, Department of Biological Functions
and Engineering, Kyushu Institute of Technology. Kitakyushu Science and Research
Park, Kitakyushu, Fukuoka 808-0196, Japan
| | - Naoya Murakami
- Division
of Photo-functional Nanomaterials, Department of Biological Functions
and Engineering, Kyushu Institute of Technology. Kitakyushu Science and Research
Park, Kitakyushu, Fukuoka 808-0196, Japan
| | - Tatsuya Sakakura
- Division
of Functional Interface Engineering, Department of Biological Functions
and Engineering, Kyushu Institute of Technology. Kitakyushu Science and Research
Park, Kitakyushu, Fukuoka 808-0196, Japan
| | - Yoshiyuki Takatsuji
- Division
of Functional Interface Engineering, Department of Biological Functions
and Engineering, Kyushu Institute of Technology. Kitakyushu Science and Research
Park, Kitakyushu, Fukuoka 808-0196, Japan
| | - Tetsuya Haruyama
- Division
of Functional Interface Engineering, Department of Biological Functions
and Engineering, Kyushu Institute of Technology. Kitakyushu Science and Research
Park, Kitakyushu, Fukuoka 808-0196, Japan
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Kawano A, Yamasaki R, Sakakura T, Takatsuji Y, Haruyama T, Yoshioka Y, Ariyoshi W. Reactive Oxygen Species Penetrate Persister Cell Membranes of Escherichia coli for Effective Cell Killing. Front Cell Infect Microbiol 2020; 10:496. [PMID: 33042869 PMCID: PMC7530241 DOI: 10.3389/fcimb.2020.00496] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 08/10/2020] [Indexed: 02/05/2023] Open
Abstract
Persister cells are difficult to eliminate because they are tolerant to antibiotic stress. In the present study, using artificially induced Escherichia coli persister cells, we found that reactive oxygen species (ROS) have greater effects on persister cells than on exponential cells. Thus, we examined which types of ROS could effectively eliminate persister cells and determined the mechanisms underlying the effects of these ROS. Ultraviolet (UV) light irradiation can kill persister cells, and bacterial viability is markedly increased under UV shielding. UV induces the production of ROS, which kill bacteria by moving toward the shielded area. Electron spin resonance-based analysis confirmed that hydroxyl radicals are produced by UV irradiation, although singlet oxygen is not produced. These results clearly revealed that ROS sterilizes persister cells more effectively compared to the sterilization of exponential cells (**p < 0.01). These ROS do not injure the bacterial cell wall but rather invade the cell, followed by cell killing. Additionally, the sterilization effect on persister cells was increased by exposure to oxygen plasma during UV irradiation. However, vapor conditions decreased persister cell sterilization by reducing the levels of hydroxyl radicals. We also verified the effect of ROS against bacteria in biofilms that are more resistant than planktonic cells. Although UV alone could not completely sterilize the biofilm bacteria, UV with ROS achieved complete sterilization. Our results demonstrate that persister cells strongly resist the effects of antibiotics and starvation stress but are less able to withstand exposure to ROS. It was shown that ROS does not affect the cell membrane but penetrates it and acts internally to kill persister cells. In particular, it was clarified that the hydroxy radical is an effective sterilizer to kill persister cells.
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Affiliation(s)
- Aki Kawano
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Japan
| | - Ryota Yamasaki
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Japan
| | - Tatsuya Sakakura
- Division of Functional Interface Engineering, Department of Biological Systems and Engineering, Kyushu Institute of Technology, Kitakyushu, Japan
| | - Yoshiyuki Takatsuji
- Division of Functional Interface Engineering, Department of Biological Systems and Engineering, Kyushu Institute of Technology, Kitakyushu, Japan
| | - Tetsuya Haruyama
- Division of Functional Interface Engineering, Department of Biological Systems and Engineering, Kyushu Institute of Technology, Kitakyushu, Japan
| | - Yoshie Yoshioka
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Japan
| | - Wataru Ariyoshi
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Kitakyushu, Japan
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Kobayashi K, Lou SN, Takatsuji Y, Haruyama T, Shimizu Y, Ohno T. Photoelectrochemical reduction of CO2 using a TiO2 photoanode and a gas diffusion electrode modified with a metal phthalocyanine catalyst. Electrochim Acta 2020. [DOI: 10.1016/j.electacta.2020.135805] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Sakakura T, Murakami N, Takatsuji Y, Morimoto M, Haruyama T. Contribution of Discharge Excited Atomic N, N 2 *, and N 2 + to a Plasma/Liquid Interfacial Reaction as Suggested by Quantitative Analysis. Chemphyschem 2019; 20:1467-1474. [PMID: 30950156 DOI: 10.1002/cphc.201900212] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 03/29/2019] [Indexed: 11/07/2022]
Abstract
Electric-discharge nitrogen comprises three main types of excited nitrogen species-atomic nitrogen (Natom ), excited nitrogen molecules (N2 *), and nitrogen ions (N2 + ) - which have different lifetimes and reactivities. In particular, the interfacial reaction locus between the discharged nitrogen and the water phase produces nitrogen compounds such as ammonia and nitrate ions (denoted as N-compounds generically); this is referred to as the plasma/liquid interfacial (P/L) reaction. The Natom amount was analyzed quantitatively to clarify the contribution of Natom to the P/L reaction. We focused on the quantitative relationship between Natom and the produced N-compounds, and found that both N2 * and N2 + , which are active species other than Natom , contributed to P/L reaction. The production of N-compounds from N2 * and N2 + was enhanced upon UV irradiation of the water phase, but the production of N-compounds from Natom did not increase by UV irradiation. These results revealed that the P/L reactions starting from Natom and those starting from N2 * and N2 + follow different mechanisms.
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Affiliation(s)
- Tatsuya Sakakura
- Division of Functional Interface Engineering Department of Biological Functions and Engineering, Kyushu Institute of Technology, Kitakyushu Science and Research Park, Kitakyushu, Fukuoka, 808-0196, Japan
| | - Naoya Murakami
- Department of Applied Chemistry, Faculty of Engineering, Kyushu Institute of Technology 1-1 Sensuicho, Tobata, Kitakyushu, Fukuoka, 804-8550, Japan
| | - Yoshiyuki Takatsuji
- Division of Functional Interface Engineering Department of Biological Functions and Engineering, Kyushu Institute of Technology, Kitakyushu Science and Research Park, Kitakyushu, Fukuoka, 808-0196, Japan
| | - Masayuki Morimoto
- Division of Functional Interface Engineering Department of Biological Functions and Engineering, Kyushu Institute of Technology, Kitakyushu Science and Research Park, Kitakyushu, Fukuoka, 808-0196, Japan
| | - Tetsuya Haruyama
- Division of Functional Interface Engineering Department of Biological Functions and Engineering, Kyushu Institute of Technology, Kitakyushu Science and Research Park, Kitakyushu, Fukuoka, 808-0196, Japan
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Takatsuji Y, Nakata I, Morimoto M, Sakakura T, Yamasaki R, Haruyama T. Highly Selective Methane Production Through Electrochemical CO2 reduction by Electrolytically Plated Cu-Co Electrode. Electrocatalysis (N Y) 2018. [DOI: 10.1007/s12678-018-0492-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Yamasaki R, Takatsuji Y, Morimoto M, Ishikawa S, Fujinami T, Haruyama T. Sustainable process for functional group introduction onto HOPG by exposing OH and 1O2 using a radical vapor reactor (RVR) without any chemical reagents. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.03.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Yamasaki R, Takatsuji Y, Asakawa H, Fukuma T, Haruyama T. Flattened-Top Domical Water Drops Formed through Self-Organization of Hydrophobin Membranes: A Structural and Mechanistic Study Using Atomic Force Microscopy. ACS Nano 2016; 10:81-87. [PMID: 26595357 DOI: 10.1021/acsnano.5b04049] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The Trichoderma reesei hydrophobin, HFBI, is a unique structural protein. This protein forms membranes by self-organization at air/water or water/solid interfaces. When HFBI forms a membrane at an air/water interface, the top of the water droplet is flattened. The mechanism underlying this phenomenon has not been explored. In this study, this unique phenomenon has been investigated. Self-organized HFBI membranes form a hexagonal structured membrane on the surface of water droplets; the structure was confirmed by atomic force microscopy (AFM) measurement. Assembled hexagons can form a planar sheet or a tube. Self-organized HFBI membranes on water droplets form a sheet with an array of hexagonal structures or a honeycomb structure. This membrane, with its arrayed hexagonal structures, has very high buckling strength. We hypothesized that the high buckling strength is the reason that water droplets containing HFBI form flattened domes. To test this hypothesis, the strength of the self-organized HFBI membranes was analyzed using AFM. The buckling strength of HFBI membranes was measured to be 66.9 mN/m. In contrast, the surface tension of water droplets containing dissolved HFBI is 42 mN/m. Thus, the buckling strength of a self-organized HFBI membrane is higher than the surface tension of water containing dissolved HFBI. This mechanistic study clarifies why the water droplets formed by self-organized HFBI membranes have a flattened top.
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Affiliation(s)
- Ryota Yamasaki
- Advanced Catalytic Transformation Program for Carbon Utilization (ACT-C), Japan Science and Technology Agency (JST) , Tokyo 102-0076, Japan
| | - Yoshiyuki Takatsuji
- Advanced Catalytic Transformation Program for Carbon Utilization (ACT-C), Japan Science and Technology Agency (JST) , Tokyo 102-0076, Japan
| | - Hitoshi Asakawa
- Advanced Catalytic Transformation Program for Carbon Utilization (ACT-C), Japan Science and Technology Agency (JST) , Tokyo 102-0076, Japan
| | - Takeshi Fukuma
- Advanced Catalytic Transformation Program for Carbon Utilization (ACT-C), Japan Science and Technology Agency (JST) , Tokyo 102-0076, Japan
| | - Tetsuya Haruyama
- Advanced Catalytic Transformation Program for Carbon Utilization (ACT-C), Japan Science and Technology Agency (JST) , Tokyo 102-0076, Japan
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Takatsuji Y, Wakabayashi R, Sakakura T, Haruyama T. A “Swingable” straight-chain affinity molecule immobilized on a semi-conductor electrode for photo-excited current-based molecular sensing. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.08.111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Takatsuji Y, Yamasaki R, Iwanaga A, Lienemann M, Linder MB, Haruyama T. Solid-support immobilization of a "swing" fusion protein for enhanced glucose oxidase catalytic activity. Colloids Surf B Biointerfaces 2013; 112:186-91. [PMID: 23974004 DOI: 10.1016/j.colsurfb.2013.07.051] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 07/10/2013] [Accepted: 07/26/2013] [Indexed: 02/04/2023]
Abstract
The strategic surface immobilization of a protein can add new functionality to a solid substrate; however, protein activity, e.g., enzymatic activity, can be drastically decreased on immobilization onto a solid surface. The concept of a designed and optimized "molecular interface" is herein introduced in order to address this problem. In this study, molecular interface was designed and constructed with the aim of attaining high enzymatic activity of a solid-surface-immobilized a using the hydrophobin HFBI protein in conjunction with a fusion protein of HFBI attached to glucose oxidase (GOx). The ability of HFBI to form a self-organized membrane on a solid surface in addition to its adhesion properties makes it an ideal candidate for immobilization. The developed fusion protein was also able to form an organized membrane, and its structure and immobilized state on a solid surface were investigated using QCM-D measurements. This method of immobilization showed retention of high enzymatic activity and the ability to control the density of the immobilized enzyme. In this study, we demonstrated the importance of the design and construction of molecular interface for numerous purposes. This method of protein immobilization could be utilized for preparation of high throughput products requiring structurally ordered molecular interfaces, in addition to many other applications.
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Affiliation(s)
- Yoshiyuki Takatsuji
- Department of Biological Functions and Engineering, Kyushu Institute of Technology, Kitakyushu Science and Research Park, Kitakyushu, Fukuoka, 808-0196, Japan; JST ACT-C, Japan
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