Zavilgelsky G B, Kotova V Yu, Manukhov I V
State Institute of Genetics and Selection of Industrial Microorganisms, 1st Dorozhnii pr 1, Moscow, Russia.
Mutat Res. 2007 Dec 1;634(1-2):172-6. doi: 10.1016/j.mrgentox.2007.07.012. Epub 2007 Aug 9.
Seven different recombinant bioluminescent strains of Escherichia coli containing, respectively, the promoters katG and soxS (responsive to oxidative damage), recA (DNA damage), fabA (membrane damage), grpE, and rpoE (protein damage) and lac (constitutive expression) fused to the bacterial operon from Photorhabdus luminescens, were used to describe the mechanism of toxicity of 1,1-dimethylhydrazine (1,1-DMH) on bacteria, as well as to determine whether bacteria can sensitively detect the presence of this compound. A clear response to 1,1-DMH was observed only in E. coli carrying the katG'::lux, soxS'::lux, and recA'::lux-containing constructs. Preliminary treatment with catalase of the medium containing 1,1-DMH completely diminished the stress-response of the P(katG), P(recA), and P(soxS) promoters. In the strain E. coli (pXen7), which contains a constitutive promoter, the level of cellular toxicity caused by the addition of 1,1-DMH was dramatically reduced in the presence of catalase. It is suggested that the action of 1,1-DMH on bacterial cells is determined by hydrogen peroxide, which is formed in response to reduction of the air oxygen level.
七种不同的重组生物发光大肠杆菌菌株分别含有katG和soxS（对氧化损伤有反应）、recA（DNA损伤）、fabA（膜损伤）、grpE和rpoE（蛋白质损伤）的启动子，以及与发光杆菌的细菌操纵子融合的lac（组成型表达）启动子，用于描述1,1 - 二甲基肼（1,1 - DMH）对细菌的毒性机制，以及确定细菌是否能灵敏地检测到这种化合物的存在。仅在携带katG'::lux、soxS'::lux和recA'::lux构建体的大肠杆菌中观察到对1,1 - DMH的明显反应。用过氧化氢酶对含有1,1 - DMH的培养基进行预处理，完全消除了P(katG)、P(recA)和P(soxS)启动子的应激反应。在含有组成型启动子的大肠杆菌菌株E. coli (pXen7)中，在过氧化氢酶存在的情况下，添加1,1 - DMH引起的细胞毒性水平显著降低。研究表明，1,1 - DMH对细菌细胞的作用是由过氧化氢决定的，过氧化氢是在空气氧水平降低时形成的。
