Glycerol and Water Effects on X-Ray Sensitivity in Staphylococcus aureus

Abstract

The variation of X-ray sensitivity of Staphylococcus aureus was studied over a range of glycerol concentrations to 95%. The relationship followed closely that described by the Langmuir adsorption equation. Extrapolation of this relationship to infinite glycerol concentration gives values of less than one-twentieth of the sensitivity of the cells in phosphate buffer. The results are not consistent with glycerol acting primarily either to prevent the oxygen-enhancement effect or by protection through the simple removal of water from the cells. Simple dehydration of this organism does not decrease X-ray sensitivity, provided a protective agent is not added before drying. It is proposed that protection by glycerol occurs through the adsorption of glycerol on sites usually occupied by water at the surface of important macro-molecules within the cell.