Biological effects of Auger processes of bromine on yeast cells induced by monochromatic synchrotron X-rays.
Biological effects of Auger processes of bromine on yeast cells induced by monochromatic synchrotron X-rays.
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单色同步加速器 X 射线诱导的溴俄歇过程对酵母细胞的生物效应。
DOI：
10.1080/09553009114552571
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发表时间：
1991
影响因子：
2.6
通讯作者：
S. Ishizaka
中科院分区：
文献类型：
--
作者：
N. Usami;Katsumi Kobayashi;H. Maezawa;K. Hieda;S. Ishizaka
利用脱氧胸苷一磷酸（dTMP）渗透性酵母突变株酿酒酵母（Saccharomycescerevisiae），研究了同步辐射单色化X射线诱导溴脱氧尿苷一磷酸（BrdUMP）掺入DNA的内壳层电离的生物学效应。用13.51或13.45 keV的单色X射线照射掺入BrdUMP的酵母细胞，溴K吸收边（13.47 keV）位于两者之间。细胞对13.51 keV X射线照射的敏感性是13.45 keV X射线照射的1.07倍，而掺入dTMP的细胞的敏感性没有任何差异。在辐射期间存在辐射保护剂的情况下，掺入BrdUMP的细胞显示出更大的增强（1.20）。在溴掺入细胞中观察到的这些增强作用不能仅用由于溴取代胸腺嘧啶的CH 3基团而增加的吸收剂量来解释。可以得出结论，增强的主要部分是由内壳层光电离引起的，随后是DNA中溴的俄歇级联。半胱胺的存在不影响溴K-壳层光吸收引起的致死率的量子产率，这表明俄歇过程的生物增强可能不受化学保护的影响。
The biological effects of inner-shell ionization in bromine atoms incorporated into DNA in the form of bromodeoxyuridine monophosphate (BrdUMP), induced by monochromatized synchrotron X-rays, were studied using a deoxythymidine monophosphate (dTMP)-permeable mutant of yeast, Saccharomyces cerevisiae. The BrdUMP-incorporated yeast cells were irradiated with monochromatic X-rays of 13.51 or 13.45 keV, between which the bromine K-absorption edge (13.47 keV) is located. The cells were 1.07 times more sensitive to irradiation by 13.51 keV X-rays than at 13.45 keV, while dTMP-incorporated cells did not show any difference in sensitivity. In the presence of a radioprotector during irradiation, BrdUMP-incorporated cells showed a larger enhancement (1.20). These enhancements observed in the bromine-incorporated cells cannot be explained only by an increase of the absorbed dose due to a substitution of CH3 group of thymine by bromine. It may be concluded that a major part of the enhancement was caused by inner-shell photoionization, followed by an Auger cascade of the bromine in the DNA. The quantum yield of lethality caused by the photoabsorption of bromine K-shell is not affected by the presence of cysteamine, suggesting the biological enhancement by the Auger processes may not be influenced by chemical protection.
哺乳动物细胞 DNA 中溴 77 衰变导致的俄歇电子的致命性。
影响因子：
3.4
作者：
Kassis,AI;Adelstein,SJ;Haydock,C;Sastry,KS;McElvany,KD;Welch,MJ
通讯作者：
Welch,MJ