Virulent Bacteriophages
Virulent (lytic) Bacteriophages, such as T2, are bacteriophages whose life-cycle always involves lysis of the host cell. In our experiment, the results of the lytic cycle are doubly important. Lysis kills the cell, allowing us to screen for T2 resistance through exposure to T2, and the lead up to lysis involves repeated replication of the virus, which means that even with a relatively low initial phage concentration, we can still ensure that any potential colonies of E.coli are introduced to T2 at some point.