Figure 1. Characterizing lysis inhibition.

Schematic of T4 infection of E. coli. (A) At low multiplicities of infection (MOI), available E. coli are readily infected by T4 (red). Under these conditions, an infected cell is hijacked to produce progeny phage and lyses releasing the phages into the environment where they go on to infect neighboring cells. (B) At high MOIs, phage outnumber the hosts resulting in initial infection by phage followed by secondary superinfection (second phage infecting the same cell). Superinfection delays lysis through LIN, enabling the production of more virions and protecting progeny phage from an environment devoid of uninfected hosts. (C) ICP1 exhibits LIN at intermediate multiplicities of infection and upon superinfection. PLE (-) V. cholerae infected with ICP1 at MOI = 1 demonstrate a lysis event 20 minutes post-infection (black arrow) before the optical density (OD₆₀₀) stabilizes. Superinfection (orange arrow) of a culture four minutes post-infection with ICP1 at MOI = 1 with ICP1 at a multiplicity of superinfection (MOSI) of 5 triggers lysis inhibition and stabilizes the OD₆₀₀ before a lysis event can occur. Data from three biological replicates are shown. (D) ICP1 LIN is sensitive to chemical collapse. PLE (-) V. cholerae infected with ICP1 at MOI = 5 maintain OD₆₀₀ for an extended period but the OD₆₀₀ collapses when 2,4-dinitrophenol (DNP) is added (black arrow). Data from four biological replicates are shown. For all graphs, points show the average of replicates; shading shows the standard deviation.