The survival of hsdR+M−(F269G)S+ cells was assessed after the conjugative transfer of hsdR+ to hsdR−M−S+ recipients. (a) The experiment using F′101–103 (hsdR+). (b) The control experiment with F′101–102 (hsdM+S+). Data are plotted for the following recipients: NK379, hsdR (▴); NK380, hsdR clpX (▿); NK382, hsdRM (□); NK384, hsdRM clpX (■); and NK383, hsdRM recA (●). The data show that hsdR+M−(F269G)S+ cells survive only if the recipient is ClpX+.