Reduction of X-ray Sensitivity of Escherichia coli B/r by Sulfhydryl Compounds, Alcohols, Glycols, and Sodium Hydrosulfite.

Abstract

Great increases in cell survival were achieved by irradiation of suspensions in the presence of sulfhydryl compounds, glycols, low molecular weight alcohols, and Na hydrosulfite. The protective action of a chemical is expressed in terms of an "isoefficiency ratio," e.g., the ratio of the X-ray dose required to kill a given number of cells in the presence of the compound to that required in the absence of the compound. The isoefficiency ratios for BAL (0.04 [image]), ethanol (3.5 [image]), and Na hydrosulfite (0.04 [image]) are 4.0, 3.1 and 3.7, respectively. The value of BAL is about twice that for compounds having only one sulfhydryl group. Other low molecular weight alcohols and the glycols are about as effective as ethanol on a molar basis. The mode of action of Na hydrosulfite is believed to be simply a removal of O2 from the bacterial suspensions.