Temporary Radiostability in Extracellular Bacteriophages after Trapping of Molecules of the Cysteine-cysteamine Group

Summary

Ten different strains of bacteriophages are checked for a new phenomenon tentatively designated as ‘phage-SH complex’. The phages are incubated in nutrient broth solution to which 0·5 M cysteine or cysteamine is added. The x-irradiation, however, is performed with the phages in an anoxic medium in which the sulphydryl concentration is reduced below that concentration sufficient for protection.

It is observed that some phages are able to acquire a temporary radioresistance. The effect of oxygen and of an SH-blocking compound on the phage-SH complex was investigated and related to phage structure. The protective mechanism is discussed in the light of current hypotheses.