Inhibition of x-ray-induced protection of Escherichia coli K-12 cells against the lethal effects of ultra-violet light by nitrofurantoin.
Inhibition of x-ray-induced protection of Escherichia coli K-12 cells against the lethal effects of ultra-violet light by nitrofurantoin.
复制标题
呋喃妥因抑制 X 射线诱导的大肠杆菌 K-12 细胞免受紫外线致死作用的保护。
DOI：
10.1080/09553007814550491
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发表时间：
1978
期刊：
影响因子：
--
通讯作者：
K. Martignoni
中科院分区：
文献类型：
--
作者：
K. Martignoni
野生型E.大肠杆菌K-12如果在紫外线照射前进行X射线照射并在37 ℃的生长培养基中培养，则显示出增加的紫外线抗性。通过在低于15 ℃的温度下或在0.01 M KCN存在下孵育经X射线照射的细胞，可以抑制更高的UV抗性的发展。呋喃妥因（NF），这是最近发现的特异性抑制诱导酶的合成，只有一个短暂的抑制作用X射线诱导的紫外线抗性。在葡萄糖培养基中生长的细胞显示NF对X-辐射诱导的抗UV的抑制较小。在甘油或葡萄糖培养基中加入环腺苷酸，这表明，X射线诱导的紫外线抗性需要活跃的细胞代谢，但它不受分解代谢物阻遏。以下假设被提供来解释NF的作用：在去阻遏条件下（没有葡萄糖的分解代谢物阻遏），呋喃妥因可以抵消辐射诱导的修复抑制剂的抑制（如辐射后DNA降解）。
Wild-type cells of E. coli K-12 showed increasing U.V. resistance if they were X-irradiated and incubated at 37 degrees C in growth medium before the U.V. exposure. Development of higher U.V. resistance could be inhibited by incubating the X-irradiated cells either at temperatures below 15 degrees C, or in the presence of 0.01 M KCN. Nitrofurantoin (NF), which was recently found specifically to inhibit inducible enzyme synthesis, had only a transient inhibitory effect on X-ray-induced U.V. resistance. Cells grown in glucose medium showed less inhibition by NF of X-radiation-induced resistance to U.V.-radiation than did cells grown in glycerol, or in glucose medium with added cyclic AMP. It is suggested that X-ray-induced U.V. resistance requires active cellular metabolism, but it is not subject to catabolite repression. The following hypothesis is offered to explain the action of NF: Under de-repressed conditions (without catabolite repression by glucose) nitrofurantoin could counteract the radiation-induced inhibition of a repair inhibitor (such as post-irradiation DNA degradation).