Figure 1.

RecD inhibits survival of recB^D1080A strains after exposure to UV light. Strains are transformants of V67 (recB21∷IS186) with the indicated rec alleles present on a plasmid. Cultures were grown to mid-log phase at 37°C in LB broth with 40 μg/ml chloramphenicol, harvested by centrifugation, resuspended in 10 mM MgSO₄, exposed to UV light, and plated on LB agar with chloramphenicol. Survival is the fraction of initial colony-forming units surviving after exposure to the indicated amount of UV light.