Grimm K
Z Allg Mikrobiol. 1978;18(6):399-407. doi: 10.1002/jobm.3630180603.
Cystobacter species strain CK 1 does not grow with more than 0.2 microgram/ml acriflavine. Spontaneous two-step mutants growing with 2 microgram acriflavine per ml have been selected. One mutant (strain CK3) was used to investigate the effect of repair inhibitors. Both strains exhibit pronounced shoulders in their UV dose curves of inactivation. Acriflavine (AF), coumarin (CU), and caffeine (CA) when incorporated in the post-irradiation plating medium decreased survival of irradiated cells. Post-treatment with 2 microgram acriflavine/ml abolished the shoulder of the curve. Caffeine (1600 microgram/ml) and coumarin (350 microgram/ml) reduced it only to about 40%. It is concluded that probably two repair mechanisms are present. Pre-treatment of the cells with 2 microgram acriflavine/ml for two hours before UV-irradiation resulted in a constant dose enhancement factor of 1.9. The protective effect is increased with the time of treatment with acriflavine. This may indicate that pyrimidine dimers are responsible for UV-inactivation.
囊杆菌属菌株CK 1在吖啶黄素浓度超过0.2微克/毫升时无法生长。已筛选出能在每毫升含2微克吖啶黄素的培养基中生长的自发两步突变体。其中一个突变体（菌株CK3）用于研究修复抑制剂的作用。两种菌株在紫外线灭活剂量曲线上均呈现明显的肩部。当吖啶黄素（AF）、香豆素（CU）和咖啡因（CA）加入辐照后平板培养基中时，会降低辐照细胞的存活率。用每毫升2微克吖啶黄素进行后处理消除了曲线的肩部。咖啡因（1600微克/毫升）和香豆素（350微克/毫升）仅将其降低至约40%。由此得出结论，可能存在两种修复机制。在紫外线照射前，用每毫升2微克吖啶黄素对细胞进行两小时预处理，导致剂量增强因子恒定为1.9。保护作用随吖啶黄素处理时间的延长而增强。这可能表明嘧啶二聚体是紫外线灭活的原因。
