Lysogenic cycle

In one mutated form of lambda the repressor protein is inactive at temperatures above 37 °C but active at lower temperatures. When this lambda is used as a vector the infected E. coli are grown first at 32 °C to allow replication of the DNA in the lysogenic cycle. The temperature is then increased to 37 °C to inactivate the repressor. This results in the excision of the lambda genome and release of lambda particles by lysis. 

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