[Protective effects of cysteamine and anoxia in Escherichia coli mutants]

The values of the oxygen effect (m) and maximum radioprotective effect of cysteamine (DMF*) have been determined for the following Escherichia coli strains: AB1157 (the wild type), AB1886 (uvrA), AB2463 (recA), and p3478 (polA). Three mechanisms are shown to be responsible for the protective effect of cysteamine, they are: (1) anoxia, (2) diminution of the indirect effect, (3) an increased efficiency of enzyme repair. Anoxia is the main contributor to the protective effect in all the strains under study while mechanism (3) is only effective in the wild type strain.