SINGLE-STRAND AND DOUBLE-STRAND BREAK FORMATION IN DNA IRRADIATED IN AQUEOUS-SOLUTION - DEPENDENCE ON DOSE AND OH RADICAL SCAVENGER CONCENTRATION
SINGLE-STRAND AND DOUBLE-STRAND BREAK FORMATION IN DNA IRRADIATED IN AQUEOUS-SOLUTION - DEPENDENCE ON DOSE AND OH RADICAL SCAVENGER CONCENTRATION
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DOI：
10.2307/3577098
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发表时间：
1987-12-01
影响因子：
3.4
通讯作者：
BOTHE, E
中科院分区：
文献类型：
--
作者：
SIDDIQI, MA;BOTHE, E
小牛胸腺DNA中单链和双链断裂（SSB和DSB）的产率，在60 Co γ射线照射后，在稀水溶液中照射，已经通过使用小角度激光光散射技术的分子量测量来确定。在不存在和存在氧气的情况下，以及在不同浓度的OH自由基清除剂苯酚、叔丁醇和甲醇的情况下，将辐照施用到含N2 O的DMBA溶液中。OH自由基产生SSB与剂量呈线性关系，在脱氧和充氧溶液中，G值分别为55 nmol J-1和54 nmol J-1。根据线性-二次剂量关系形成DSB，线性形成的DSB的G值为GDSB α。（室温）= 3.5 nmol J ~（-1），含氧溶液为3.2 nmol J ~（-1）。GSSB/GDSB α的比率。（室温）= γ。19 +-。6是独立的清除剂浓度的情况下，叔丁醇和甲醇的解决方案。GDSB.alpha.（室温）被解释为由从切割链的糖部分转移到互补完整链的自由基位点产生。这种自由基转移和随后的第二条链断裂的过程以约6 ± 1的概率发生。2%，在氧气的存在下，在所有的scanger浓度研究。这些关于GDSB α的清除能力的数据。（室温）表明通过自由基转移产生的双链断裂仍然高于直接作用产生的双链断裂，高达约109 s-1的清除能力。
The yields of single- and double-strand breaks (SSB and DSB) in calf thymus DNA, after 60Co .gamma. irradiation in dilute aqueous solution, have been determined via molecular weight measurements using a low-angle laser light scattering technique. The irradiations were administered to to N2O-containing solutions of DNBA in the absence and presence of oxygen and with different concentrations of the OH radical scavengers phenol, tertiary butanol, and methanol. OH radicals were found to produce SSB linearly with dose with a G value of 55 nmol J-1 and 54 nmol J-1 in deoxygenated and oxygenated solutions, respectively. DSB were formed according to a linear-quadratic dose relationship and the G value of linearly formed DSB were GDSB.alpha.(r.t.) = 3.5 nmol J-1 in deoxygenated and 3.2 nmol J-1 in oxygenated solution. The ratio of GSSB/GDSB.alpha.(r.t.) = .gamma. of 19 .+-. 6 was independent of the scavenger concentration in the case of tertiary butanol and methanol-containing solutions. GDSB.alpha.(r.t.) is interpreted to result from a radical site transferred from a sugar moiety of the cleaved strand to the complementary intact strand. This process of radical transfer and subsequent cleavage of the second strand occurs with a probability of about 6 .+-. 2% in the presence of oxygen at all scanger concentrations studied. These data on scavenging capacity on GDSB.alpha.(r.t.) suggest that the double-strand breakage produced via radical transfer remains higher than that resulting from direct effect, up to scavenging capacities of about 109 s-1.