Structural Biochemistry/DNA recombinant techniques/Plasmid/Lysogenic Pathway

Overview

During the lysogenic pathway, a lambda phage containing virus DNA attaches itself onto a host bacterium cell containing a plasmid. The lambda phage releases into the host cell where it is integrated into the host's genome. The phage DNA is then incorporated into the host chromosome and is replicated along with the rest of the host's DNA and remains inactive. This can continue for several generations until environmental factors activate the expression of the dormant phage DNA. The progeny DNA is then released from the host genome and is enclosed into virus packages. The bacterium then lyses and releases the progeny virus particles also called virions.

According to an article posted in the September 2008 issue of Biophysical Journal,a new study reveals that these bacteria infecting cells can make collective decisions on whether they should kill host cells immediately after infection or enter a present, but not visible state to remain in the host cell. The fate of a cell is controlled by the number of infecting diseases in a coordinated fashion. According to Joshua Weitz, a Georgia Tech professor, he states, "In the case of perhaps the most extensively studied bacteriophage, lambda phage, experimental evidence indicates that a single infecting phage leads to host cell death and viral release, whereas if two or more phages infect a host, the outcome is typically latency."