OVERLAP OF PHOTOREACTIVATION AND LIQUID HOLDING RECOVERY IN ESCHERICHIA COLI B.

It is known that cells of Escherichia coli B exposed to 2537-A ultraviolet radiation will show a higher survival (photoreactivation) if subsequently irradiated at 3650 A and that they will also show a higher survival (liquid holding recovery) if subsequently held in a liquid. We find that cells given an optimal recovery treatment of one type show no further recovery if also subjected to the other type of treatment. It is concluded that liquid holding treatment acts only upon photoreactivable damage.