Proton-Cluster-Beam Lethality and Mutagenicity in Bacillus subtilis Spores
Proton-Cluster-Beam Lethality and Mutagenicity in Bacillus subtilis Spores
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DOI：
10.3390/qubs5030025
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发表时间：
2021-09-01
影响因子：
1.4
通讯作者：
Narumi, Kazumasa
中科院分区：
文献类型：
--
作者：
Hase, Yoshihiro;Satoh, Katsuya;Narumi, Kazumasa
快速簇离子独特的能量传递特性吸引了许多从事材料表面分析或处理的研究人员的注意，但对生物体的影响尚不清楚。用单体质子束和团束质子束辐照枯草芽孢杆菌孢子，观察其致死性；2 MeV H-2（+）的杀伤力明显低于340 keV H+，尽管两者具有相当的线性能量转移。2 MeV的H-2（+）通过在目标表面失去成键电子而解离成一对1 MeV的H+。估计的核间距离和径向剂量分布表明，在相隔几纳米的两个区域上沉积的总能量的分布大大降低了光束的杀伤力，而弹道正中心的能量密度，可能在1纳米半径内，对杀伤力有很大影响。我们还对幸存的菌落进行了全基因组重测序，以比较突变的分子性质，但未能发现总体特征的明显差异。我们的结果表明，簇束可能是理解高线性能量传递辐射的生物效应的有用工具。
The unique energy transfer characteristics of swift cluster ions have attracted the attention of many researchers working on the analysis or processing of material surfaces, but the effects on living organisms remain unclear. We irradiated B. subtilis spores with monomer and cluster proton beams and examined their lethality; the 2 MeV H-2(+) shows a clearly lower lethality than 340 keV H+, even though both have a comparable linear energy transfer. The 2 MeV H-2(+) dissociates into a pair of 1 MeV H+ by losing the bonding electrons at the target surface. The estimated internuclear distance and the radial dose distribution suggest that the spread of deposited total energy over two areas separated by just several nanometers greatly diminishes beam lethality and that the energy density in the very center of the trajectory, possibly within a 1 nm radius, has a great impact on lethality. We also performed a whole genome resequencing of the surviving colonies to compare the molecular nature of mutations but failed to find a clear difference in overall characteristics. Our results suggest that cluster beams may be a useful tool for understanding biological effects of high linear energy transfer radiation.