Vexler F B
Institute of Biological Physics, Acad. Sci. USSR, Pushchino, Moscow Region.
Radiat Res. 1988 Jun;114(3):550-5.
The values of the oxygen effect (m) and the maximal protective effect of cysteamine (DMF*) were estimated for four Escherichia coli strains: AB1157 (wild type), AB1886 (uvrA), AB2463 (recA), and p3478 (polA). A correlation made between DMF* and m as well as the kinetics of the increase of DMF with oxygen depletion showed that the protective effect of cysteamine is realized by three mechanisms: (i) anoxia achieved by oxygen reduction, with the DMF varying from 2.2 to 4.2 for different E. coli strains (this protection is the major contribution to the entire mechanism); (ii) lowering of the indirect radiation effect; i.e., for 50 mM cysteamine DMF does not exceed 1.1; and (iii) increase of the efficiency of enzymatic repair. The latter effect of cysteamine is registered only with the wild-type E. coli, the DMF being not less than 1.4.
AB1157（野生型）、AB1886（uvrA）、AB2463（recA）和p3478（polA），估算了氧效应值（m）和半胱胺的最大保护效应（DMF*）。DMF*与m之间的相关性以及DMF随氧消耗的增加动力学表明，半胱胺的保护作用通过三种机制实现：（i）通过氧还原实现缺氧，不同大肠杆菌菌株的DMF在2.2至4.2之间变化（这种保护是整个机制的主要贡献）；（ii）降低间接辐射效应；即对于50 mM半胱胺，DMF不超过1.1；（iii）提高酶促修复效率。半胱胺的后一种效应仅在野生型大肠杆菌中观察到，DMF不小于1.4。
