FIG. 2.

S105_ΔTMD1 is an absolute defective holin. (A and C) Cultures of the nonsuppressing hosts RY16504 (lacI^q) (A) and RY17303 (Δlac) (C) carrying the indicated prophages and/or plasmids were induced at time zero and monitored for A₅₅₀ (filled symbols) as described in Materials and Methods. The abscissa is time after induction (min) for all panels except B. (A) Plasmids pS105R_amRz_amRz1_am (▪), pS107R_amRz_amRz1_am (•), pS105_A52VR_amRz_amRz1_am (▴), pS105_ΔTMD1R_amRz_amRz1_am (⧫), and pS105_amR_amRz_amRz1_am (▾). (B) Titers of surviving phage in cultures from panel A, plated at 60 min (odd-numbered bars) or 120 min (even-numbered bars). S alleles S105 (bars 1 and 2), S107 (bars 3 and 4), S_A52V (bars 5 and 6), S105_W56am (bars 7 and 8), and S105_ΔTMD1 (bars 9 and 10). Numbers above bars 1, 2, and 4 indicate percent survival. (C) Prophages λS105 (▪), λS107 (•), λS105_A52V (▴), λS105_ΔTMD1_Δ (⧫), and λS105_W56am (▾). Accumulations of phage (PFU) are also shown with corresponding open symbols.