Figure 1.
Sensitivity of lamdoid bacteriophages to UV irradiation. Lysates of phages (indicated in each panel) were either non-irradiated (open symbols) or UV-irradiated at 50 J/m2 (closed symbols), and E. coli MG1655 cells were infected at 37 °C (solid lines) or 43 °C (dashed lines). Phage titer was determined at indicated times after irradiation by estimating number of plaque forming units (pfu) per mL. Results are presented as mean values from three independent experiments with error bars indicating SD, however the bars are smaller than the size of symbols. For all experiments but those with bacteriophage λ, statistically significant differences (p < 0.05 in the t-tets) between irradiated and non-irradiated phages were found. The use of phage lysates of different initial titers gave very similar results, thus, the sensitivity to UV irradiation was independent on virion density.