Villa L L, Juliani M H
Mutat Res. 1980 Jun;71(1):67-75. doi: 10.1016/0027-5107(80)90007-x.
We have studied the induction of rho- mutants by guanidine hydrochloride (GuHCl) in combination with other known inducers: ethidium bromide (EB), berenil and ultraviolet light. Competition was observed when cells were simultaneously treated with optimal concentrations of EB and GuHCl; on the other hand, treatment of cells with EB in the presence of non-inducing concentrations of GuHCl resulted in the stimulation of rho- induction of EB. Furthermore, using a strain which upon treatment with high EB concentrations shows recovery of respiratory competence, the presence of GuHCl did not interfere either with the early phase of induction or with the recovery phase, but it did interfere in a competitive fashion with the final irreversible phase of EB induction. In the case of berenil, a synergistic effect was seen when cells were pretreated with GuHCl. A synergistic induction was also observed when cells were submitted to UV prior to GuHCl treatment. These results suggest that GuHCl, EB and berenil act via some common step in their rho- induction pathways. Moreover, GuHCl may somehow be decreasing the efficiency of dark repair of ultraviolet lesions on mitochondrial DNA.
我们研究了盐酸胍（GuHCl）与其他已知诱导剂：溴化乙锭（EB）、贝尼尔和紫外线联合诱导rho-突变体的情况。当细胞同时用最佳浓度的EB和GuHCl处理时，观察到了竞争现象；另一方面，在非诱导浓度的GuHCl存在下用EB处理细胞，会刺激EB诱导rho-。此外，使用一种在用高浓度EB处理后显示呼吸能力恢复的菌株，GuHCl的存在既不干扰诱导的早期阶段，也不干扰恢复阶段，但它确实以竞争方式干扰了EB诱导的最终不可逆阶段。就贝尼尔而言，当细胞用GuHCl预处理时，会出现协同效应。当细胞在GuHCl处理之前接受紫外线照射时，也观察到了协同诱导。这些结果表明，GuHCl、EB和贝尼尔在其rho-诱导途径中通过一些共同步骤起作用。此外，GuHCl可能以某种方式降低了线粒体DNA上紫外线损伤的暗修复效率。
