On the nature of HNO₂ and UV damages in T-even bacteriophages

Summary

The interpretation of experiments with HNO₂-inactivated phage T4 published byHarm (1960) and of similar experiments with UV inactivated phages T2 and T4 (Dulbecco 1952,Harm 1956, andEpstein 1958) is discussed. Two alternative theories are used as possible interpretations of the HNO₂ experiments: (1) The “injection damage” theory holding that a fractionJ of the damages caused in a phage by HNO₂ treatment prevent participation of the phage in the infectious process. (2) The “finite damage” theory holding that the damages produced by HNO₂ in the genetic material are much larger (have a greater target length) than UV damages, and otherways applying to HNO₂ damages the same theory earlier applied to UV-damages (Barricelli 1956 and 1960).

Experimental methods to decide between the two theories are indicated. In the conclusion it is shown that the injection damage theory is not valid for UV damages in T2 and T4. In this case the theory is ruled out by the results ofDulbecco's (1952),Harm's (1956) andEpstein's (1958) MR experiments.