Spin-trapping reactions of a novel gauchetype radical trapper G-CYPMPO

Oka, Toshitaka; Yamashita, Shinichi; Midorikawa, Masamichi*; Saiki, Seiichi; Muroya, Yusa*; Kamibayashi, Masato*; Yamashita, Masayuki*; Anzai, Kazunori*; Katsumura, Yosuke*

Analytical Chemistry, 83(24), p.9600 - 9604, 2011/10

https://doi.org/10.1021/ac2023926

Chemical reactions of a novel gauche-type spin trap, G-CYPMPO (-5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphinan-2-yl)-5-methy-1-pyrroline 1-oxide, torsion angle: O1-P1-C6-N1 of 52.8), with reactive oxygen species were examined by pulse radiolysis technique with 35 MeV electron beam and electron spin resonance spectroscopy after Co -ray irradiation. The spin trapping reaction rate constants of G-CYPMPO toward hydroxyl radical and hydrated electron were estimated to be (4.20.1)10 and (11.80.2)10 Ms, respectively. Half-lives of spin adducts, hydroxyl radical and perhydroxyl radical adducted G-CYPMPO were estimated to be 35 and 90 min, respectively. A comparison of the results with earlier reports using different radical sources suggests that the purity of the solution and/or the radical generation technique may influence the stability of spin adducts.

TANPOPO: astrobiology exposure and micrometeoroid capture experiments; For understanding survival possibility of trans-space migration of microorganisms

Yokobori, Shinichi*; Yang, Y.*; Fujisaki, Kenta*; Kawaguchi, Yuko*; Kobayashi, Kensei*; Hashimoto, Hirofumi*; Kawai, Hideyuki*; Mita, Hajime*; Narumi, Issei; Okudaira, Kyoko*; et al.

no journal, , 

no abstracts in English

TANPOPO (Astrobiology Exposure and Micrometeoroid Capture Experiments on ISS-JEM KIBO); Investigation of possible survivability of microorganisms in space

Yokobori, Shinichi*; Fujisaki, Kenta*; Kawaguchi, Yuko*; Yang, Y.*; Fushimi, Hidehiko*; Hashimoto, Hirofumi*; Yamashita, Masamichi*; Yano, Hajime*; Okudaira, Kyoko*; Hayashi, Nobuhiro*; et al.

no journal, , 

no abstracts in English

Water radiolysis with therapeutic high-energy heavy-ion beams; Yield of OH radical near the Bragg peak

Yamashita, Shinichi; Funtowiez, D.*; Maeyama, Takuya*; Midorikawa, Masamichi*; Oka, Toshitaka; Baldacchino, G.*; Taguchi, Mitsumasa; Kimura, Atsushi; Kudo, Hisaaki*; Katsumura, Yosuke; et al.

no journal, , 

Product yields of water radiolysis are inevitably important in understanding detailed mechanism of indirect action of ionizing radiations. We have conducted yield measurement of main products such as hydrated electron, hydroxyl radical (OH) and hydrogen peroxide. We have also developed a sensitive method to determine OH yield with a fluorescent probe. In the method, aqueous solution of coumarin-3-carboxylic acid (CCA) is irradiated and OH is scavenged by CCA, resulting in production of fluorescent product 7OH-CCA. Applying this method, OH yield near the Bragg peak has been measured in this study because the Bragg peak is overlapped cancer position in actual therapy. Beams of C 290 and 135 MeV/u and so on were taken for irradiation at the biological irradiation port at HIMAC facility of NIRS. It was found that OH yield show minimal value around the Bragg peak for every ion beam and it drastically jumps up several times at just downstream of the Bragg peak. It is already well known that contributions of fragmentation particles become non-negligible for high-energy heavy ions. Thus, further consideration including fragmentations is necessary to separate contributions of different fragmentation particles. Such consideration is being attempted by using simulations with HIBRAC and PHITS.

Detection and quantification of the spin adduct produced from CYPMPO and water decomposition radicals

Oka, Toshitaka; Yamashita, Shinichi; Midorikawa, Masamichi*; Saiki, Seiichi; Muroya, Yusa*; Lin, M.; Kamibayashi, Masato*; Anzai, Kazunori*; Kudo, Hisaaki*; Katsumura, Yosuke

no journal, , 

Detection and quantification of the oxidative radicals such as hydroxyl radical or superoxide anion radical are very important to clarify the biological oxidative damages. These oxidative radicals, produced by water decomposition with -ray irradiation, were detected as spin adducts of CYPMPO and themselves. In this work, reactivity CYPMPO and behavior of spin adducts were investigated.

Measurement of the reactivity of a novel spin-trapping agent, CYPMPO, by pulse radiolysis study

Midorikawa, Masamichi*; Oka, Toshitaka; Yamashita, Shinichi; Muroya, Yusa*; Lin, M.; Kamibayashi, Masato*; Anzai, Kazunori*; Kudo, Hisaaki*; Katsumura, Yosuke

no journal, , 

5-(2,2-dimethyl-1,3-propoxy cyclophosphoryl)-5-methyl-1pyrroline N-oxide (CYPMPO) is a recently developed spin-trapping agent, which is expected to distinguish O from OH. We have determined its reactivity with water decomposed radicals, especially with OH and with e by pulse radiolysis, and compared results with commonly-used spin trapping agent, 5,5-dimethyl-1-pyrroline N-oxide (DMPO). Furthermore, the reactions with oxidative radicals such as COO, NO and Br have also been investigated.

Microbe space exposure experiment at International Space Station (ISS) proposed in "Tanpopo" mission

Yokobori, Shinichi*; Yang, Y.*; Sugino, Tomohiro*; Kawaguchi, Yuko*; Fushimi, Hidehiko*; Narumi, Issei; Hashimoto, Hirofumi*; Hayashi, Nobuhiro*; Kawai, Hideyuki*; Kobayashi, Kensei*; et al.

no journal, , 

Trapping of the water decomposed radicals by spin-trap CYPMPO, 2

Oka, Toshitaka; Yamashita, Shinichi; Saiki, Seiichi; Midorikawa, Masamichi*; Delamea, N.*; Katsumura, Yosuke; Kamibayashi, Masato*; Anzai, Kazunori*

no journal, , 

A novel spin-trap CYPMPO (5-(2,2-dimethyl-1,3-propoxy cyclophos-phoryl)-5-methyl-1-pyrroline N-oxide) was applied to detect the water decomposed radicals using by ESR (Electron Spin Resonance) spectroscopy, and their lifetimes were estimated.

Tanpopo: astrobiology exposure and micrometeoroid-capture experiments; On the capture and space exposure experiments

Yokobori, Shinichi*; Yang, Y.*; Kawaguchi, Yuko*; Sugino, Tomohiro*; Takahashi, Yuta*; Narumi, Issei; Takahashi, Yuichi*; Hayashi, Nobuhiro*; Yoshimura, Yoshitaka*; Tabata, Makoto*; et al.

no journal, , 

no abstracts in English

Microbe space exposure experiments at International Space Station (ISS) in the mission "Tanpopo"

Yokobori, Shinichi*; Yang, Y.*; Sugino, Tomohiro*; Kawaguchi, Yuko*; Takahashi, Yuta*; Narumi, Issei; Hashimoto, Hirofumi*; Hayashi, Nobuhiro*; Imai, Eiichi*; Kawai, Hideyuki*; et al.

no journal, ,