||The lysis times and burst sizes of ?-phages were determined as described previously (Wang 2006). Briefly, the lysis time was determined by subjecting the lysogen culture to a temperature-shift regimen of 30°–42° and then finally 37° to thermally induce the excision of prophage from the bacterial chromosome. The time of initial decline of the culture turbidity (A550) was recorded as the lysis time. For burst size determination, exponentially grown bacterial culture, after preadsorption of the phages at a low multiplicity of infection (m.o.i.) of ~0.01, was immediately diluted and incubated at 37° for a certain period, depending on the lysis time. The fold of increase of phage concentration is used as the average burst size.