Heavy-ion beam-induced reactive oxygen species and redox reactions

Abstract

Quantification and local density estimation of radiation-induced reactive oxygen species (ROS) were described focusing on our recent and related studies. Charged particle radiation, i.e. heavyion beams, are currently utilized for medical treatment. Differences in ROS generation properties between photon and charged particle radiation may lead to differences in the quality of radiation. Radiation-induced generation of ROS in water was quantified using several different approaches to electron paramagnetic resonance (EPR) techniques. Two different densities of localized hydroxyl radical (OH) generation, i.e. milli-molar and molar levels, were described. Yields of sparse OH decreased with increasing linear energy transfer (LET), the yield total OH was not affected by LET. In the high-density, molar level, OH environment, OH can react and directly make hydrogen peroxide (H 2 O 2), and then possible to form a high-density H 2 O 2 cluster. The amount of total oxidation reactions caused by oxidative ROS, such as OH and hydroperoxyl radial (HO 2), was decreased with increasing LET. Possibilities of the sequential reactions were discussed based on the initial localized density at the generated site. Water-induced ROS have been well investigated. However, little is known about radiation-induced free radical generation in lipidic conditions. Radio-chemistry to understand the sequential radio-biological effects is still under development.

Effects of Carbon Ion Beam-induced Mutagenesis for the Screening of RED Production-deficient Mutants of Streptomyces Coelicolor JCM4020

“…ROS can be generated by UV irradiation, as well as heavy-ion irradiation. 42 The results indicate that the majority of mutation types [71.0%, (13+9)/31] are similar to the mutations induced by UV (C to T) or ROS (C to A). Additionally, when we mapped the 44 point mutations on the genome, the distribution was found to be relatively even across the whole genome.…”

Effects of carbon ion beam-induced mutagenesis for the screening of RED production-deficient mutants of Streptomyces coelicolor JCM4020

“…G to T is a signature point mutation induced by reactive oxygen species (ROS). ROS can be generated by UV irradiation, as well as heavy-ion irradiation [ 48 ]. The results indicate that the majority of mutation types [71.0%, (13+9)/31] are similar to the mutations induced by UV (C to T) or ROS (C to A).…”

Common methods in mitochondrial research (Review)

“…Also known as electron paramagnetic resonance (EPR), its principle is similar to nuclear magnetic resonance (322)(323)(324)(325). The sample is controlled in a fixed frequency microwave and the applied magnetic field is then changed so that the electron energy level difference is the same as the microwave energy (326,327). Unpaired electrons can move between the two energy levels and the net absorption energy of the microwave can be measured to obtain the ESR spectrum.…”