QUANTITATIVE EVIDENCE FOR ENZYMATICALLY-INDUCED DNA DOUBLE-STRAND BREAKS AS LETHAL LESIONS IN UV IRRADIATED POL+ AND POLA1 STRAINS OF E-COLI K-12
QUANTITATIVE EVIDENCE FOR ENZYMATICALLY-INDUCED DNA DOUBLE-STRAND BREAKS AS LETHAL LESIONS IN UV IRRADIATED POL+ AND POLA1 STRAINS OF E-COLI K-12
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DOI：
10.1111/j.1751-1097.1975.tb06743.x
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发表时间：
1975-01-01
影响因子：
3.3
通讯作者：
SMITH, KC
中科院分区：
文献类型：
--
作者：
BONURA, T;SMITH, KC
最近报道，在大肠杆菌K-12的uvr+菌株中，在切除修复过程中酶促产生DNA双链断裂。紫外线照射E. coli K-12 pol+（JG 139）和polA 1（JG 138）菌株具有明显的肩部区域。存活曲线的区域，在该区域，杀伤接近指数对应于DNA双链断裂（假定为致死事件）线性累积的能量密度。减少UV光产物的数量，无论是通过光复活或通量分馏的结果在增加的生存和减少在两个菌株的DNA双链断裂的产量。这些数据支持了这样的假设，即酶诱导的DNA双链断裂可能是紫外线诱导的大肠杆菌pol+菌株细胞死亡的最终原因。coli K-12中，可能也存在polA 1菌株。通过光复活或能量密度分级分离的光产物导致两种菌株中存活率的增加和DNA双链断裂产率的降低。这些数据支持了这样的假设，即酶诱导的DNA双链断裂可能是紫外线诱导的大肠杆菌pol+菌株细胞死亡的最终原因。大肠杆菌K-12，也许也存在于polA 1菌株中。
It was recently reported that DNA double-strand breaks arise enzymatically during the course of excision repair in uvr+ strains of Escherichia coli K-12. Survival curves for UV irradiated E. coli K-12 pol+ (JG139) and polA1 (JG138) strains have a pronounced shoulder region. The regions of the survival curves at which killing approaches exponential correspond to the fluences at which DNA double-strand breaks (assumed to be lethal events) accumulate linearly. Reducing the number of UV photoproducts either by photoreactivation or fluence fractionation results in an increase in survival and a decrease in the yield of DNA double-strand breaks in both strains. These data support the hypothesis that enzymatically-induced DNA double-strand breaks may be the lesion ultimately responsible for UV-induced cell killing in the pol+ strain of E. coli K-12 and perhaps also in the polA1 strain. photoproducts either by photoreactivation or fluence fractionation results in an increase in survival and a decrease in the yield of DNA double-strand breaks in both strains. These data support the hypothesis that enzymatically-induced DNA double-strand breaks may be the lesion ultimately responsible for UV-induced cell killing in the pol+ strain of E. coli K-12 and perhaps also in the polA1 strain.