Influences of -Mercaptoethylamine and Oxygen Removal on the X-ray Sensitivity of Four Strains of Escherichia coli

Abstract

In four strains of Escherichia coli B/r (ORNL), B (ORNL), B (Hill), Bs (Hill) protection by [beta]-mercaptoethylamine (MEA) exceeded that observed for oxygen removal by nitrogen bubbling. Although only a slight decrease of protection was found with strain Bs (Hill) when oxygen was removed by nitrogen bubbling, the protection afforded by MEA in excess of that achieved by nitrogen bubbling was similar with all four strains. The data suggest that at least two mechanisms for protection by MEA may operate simultaneously in some bacteria, and that one of these is a removal of oxygen equivalent to that achieved by nitrogen gas bubbling.