Lytic cycle

The lytic cycle is often separated into six stages: attachment, penetration, transcription, biosynthesis, maturation, and lysis.

[citation needed] The sequence of events that occur during initiation of bacteriophage infection, from adsorption (attachment) through DNA ejection from the virion into the host cell (penetration), was reviewed by Molineux.

The virus's nucleic acid uses the host cell's metabolic machinery to make large amounts of viral components.

This releases progeny virions into the surrounding environment, where they can go on to infect other cells and another lytic cycle begins.

[citation needed] Q-mediated turn-on of late transcription begins about 6–8 min after infection if the lytic pathway is chosen.

In overview, the holin protein accumulates in the cytoplasmic membrane until suddenly forming micron-scale holes, which triggers lysis.

The spanin proteins Rz and Rz1 accumulate in the cytoplasmic and outer membranes, respectively, and form a complex spanning the periplasm through the meshwork of the peptidoglycan.

Destruction of the peptidoglycan by the endolysin and disruption of the outer membrane by the spanin complex are both required for lysis in lambda infections.

Repeated super-infection can cause the T4 infection to continue without lysis for hours, leading to accumulation of virions to levels 10-fold higher than normal.