Growth phase-dependent UV-C resistance of Bacillus subtilis: data from a short-term evolution experiment

After 700 generations of a short-term evolution experiment with Bacillus subtilis 168, two strains were isolated, the UV-adapted strain MW01 and the UV-unexposed control strain DE69, and chosen for UV-C radiation resistance studies with respect to growth phase. The ancestral strain from the evolution experiment was used as reference for comparative purposes. Cells of the UV-adapted strain showed significant differences in their physiology (growth behavior, doubling time, cell density, and sporulation capacity) and were more resistant to UV in all monitored stages. These findings implicate the evolution to an increased UV radioresistance was not limited to a specific growth phase and led to reduced growth dynamics, compared with those obtained from the ancestral and the control strain.