Lambda Phage


Enterobacteria phage λ (lambda phage, coliphage λ) is a bacterial virus, or bacteriophage, that infects the bacterial species Escherichia coli. This virus is temperate and may reside within the genome of its host through lysogeny.

Lambda phage consists of a virus particle including a head (also known as a capsid), a tail, and tail fibers. The head contains the phage's double-stranded circular DNA genome. The phage particle recognizes and binds to its host, E. coli, causing DNA in the head of the phage to be ejected through the tail into the cytoplasm of the bacterial cell. Usually, a "lytic cycle" ensues, where the lambda DNA is replicated many times and the genes for head, tail and lysis proteins are expressed. This leads to assembly of multiple new phage particles within the cell and subsequent cell lysis, releasing the cell contents, including virions that have been assembled, into the environment. However, under certain conditions the phage DNA may integrate itself into the host cell chromosome in the lysogenic pathway. In this state, the λ DNA is called a prophage and stays resident within the host's genome without apparent harm to the host. The host can be termed a lysogen when a prophage is present.

Read more about Lambda PhageDiscovery, Anatomy, Lytic or Lysogenic?, Lambda As A Genetic Tool

Other articles related to "lambda phage, lambda, phage":

Lambda Phage - Lambda As A Genetic Tool
... Lambda phage has been of major importance in the study of specialized transduction. ...
Esther Lederberg - Contributions To Microbiology and Genetics - Lambda Bacteriophage and Specialized Transduction
... Esther Lederberg was the first to isolate lambda bacteriophage, a DNA virus, from Escherichia coli K-12 in 1950 ... Lambda phage genetic material consists of a double-stranded DNA molecule with 5' twelve-base-pair sticky ends (cos sites), which permit circularization of the DNA molecule ... Lambda phage is considered a 'temperate bacteriophage' one whose genome incorporates with and replicates with that of the host bacterium ...
Superinfection Immunity in Lambda Phage
... When a cell is a lambda lysogen, another lambda phage that infects is not able to undergo lytic development and produce phage ... The incoming phage can inject DNA, but the DNA is immediately shut down and no transcription/translation of the lambda initiates ... Therefore, lambda lysogens are immune to infection by another lambda phage particle ...