Isolation and Characterization of an Escherichia coli ruv Mutant Which Forms Nonseptate Filaments After Low Doses of Ultraviolet Light Irradiation
Isolation and Characterization of an Escherichia coli ruv Mutant Which Forms Nonseptate Filaments After Low Doses of Ultraviolet Light Irradiation
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低剂量紫外线照射后形成非隔膜丝的大肠杆菌 ruv 突变体的分离和表征
DOI：
10.1128/jb.117.2.337-344.1974
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发表时间：
1974
影响因子：
3.2
通讯作者：
Y. Hideshima
中科院分区：
文献类型：
--
作者：
N. Otsuji;H. Iyehara;Y. Hideshima
从大肠杆菌 K-12 中分离出两种紫外线 (UV) 敏感突变体。这些突变体被命名为 RuvA− 和 RuvB−，由染色体图上靠近 his 基因的基因控制。它们对紫外线敏感（增加 10 至 20 倍），对伽马射线轻微敏感（增加 3 倍）。在这些突变体中，宿主细胞重新激活、紫外线重新激活和基因重组都是正常的。用紫外线照射突变体会导致脱氧核糖核酸产生单链断裂，并在生长培养基中孵育后修复。在紫外线照射后，这些突变体像亲代野生型细菌一样以正常速率恢复脱氧核糖核酸合成，并形成无隔膜的多核丝。从这些结果我们得出结论，突变体在低剂量紫外线照射后细胞分裂存在一些缺陷，类似于大肠杆菌的 lon− 或 fil+ 突变体。根据萘啶酸敏感性和最小琼脂或泛酰内酯对紫外线照射的细胞存活的影响，将 ruv 基因座进一步分为 ruvA 和 ruvB。 ruvB-突变体比ruvA-和亲本菌株对萘啶酸更敏感。当将经紫外线照射的ruvB-突变体涂在含有泛酰内酯的基本琼脂或L琼脂上时，其存活分数显着增加。在ruvA−突变体中没有观察到这种存活率的增加。
Two ultraviolet light (UV)-sensitive mutants have been isolated from Escherichia coli K-12. These mutants, designated RuvA− and RuvB−, were controlled by a gene located close to the his gene on the chromosome map. They were sensitive to UV (10- to 20-fold increase) and slightly sensitive to gamma rays (3-fold increase). Host cell reactivation, UV reactivation and genetic recombination were normal in these mutants. Irradiation of the mutants with UV resulted in the production of single-strand breaks in deoxyribonucleic acid, which was repaired upon incubation in a growth medium. After UV irradiation, these mutants resumed deoxyribonucleic acid synthesis at a normal rate, as did the parent wild-type bacteria, and formed nonseptate, multinucleate filaments. From these results we concluded that the mutants have some defect in cell division after low doses of UV irradiation, similar to the lon− or fil+ mutant of E. coli. The ruv locus was divided further into ruvA and ruvB with respect to nalidixic acid sensitivity and the effect of minimal agar or pantoyl lactone on survival of the UV-irradiated cell. The ruvB−mutant was more sensitive to nalidixic acid than were ruvA− and the parent strain. There was a great increase in the surviving fraction of the UV-irradiated ruvB− mutant when it was plated on minimal agar or L agar containing pantoyl lactone. No such increase in survival was observed in the ruvA− mutant.