Fig 3.

Saltatory λRz_am/Rz1_am lysis is an artifact. The effect of various physiological parameters on cell lysis was assessed following induction of λ prophages. (A) Shearing forces attendant on flask shaking complement the λRz_am/Rz1_am lysis defect. The following prophage inductions were conducted with constant shaking: λ (open circles), λRz_am/Rz1_am in LB plus 10 mM Mg²⁺ (closed diamonds), and λRz_am/Rz1_am (open diamonds). For the following prophage inductions, culture shaking was ceased at 45 min after induction: λ (closed circles) and λRz_am/Rz1_am (closed triangles). (B) The Mg²⁺-dependent lysis defect is complemented by growth in a baffled flask. For the λ (circles) and λRz_am/Rz1_am (squares) inductions, shaking was ceased and the temperature decreased to 30°C 45 min postinduction. The λRz_am/Rz1_am (diamonds) prophage was induced in a baffled flask in the presence of 10 mM Mg²⁺. (C) Late-log-phase induction leads to a Mg²⁺-independent lysis defect. For the following prophage inductions, culture shaking was ceased at 45 min after induction: λ (closed circles) and λRz_am/Rz1_am (closed squares). The following prophage inductions were subjected to constant shaking: λ (open circles), λRz_am/Rz1_am in LB plus 10 mM Mg²⁺ (closed diamonds) and λRz_am/Rz1_am (open squares).