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Bacteriophage Lambda

Bacteriophage lambda is a type of virus that infects bacteria. Specifically, Bacteriophage lambda only targets Escherichia coli. Bacteriophage behave as parasites, feeding off of their hosts. Once bacteriophage lambda infects E. coli, more phages ( or viruses) are replicated within an E. coli bacterium.

  1. Structure

    • The main components of Bacteriophage lambda are its genetic material and the outside protein coat. Bacteriophage lambda consists of eight proteins, a double stranded DNA molecule, tail fibers and a tail. The coating design of phage protein allows the phage to infect E. coli without the phage's DNA being deconstructed. As a result, a phage can go from cell to cell while multiplying without being harmed.

    Bacteriophage Tail

    • According to Microbiology and Immunology, the tail fibers of the lambda will help the phage become attached to the cell of an E.coli bacterium. Once lambda has bound itself to an E. coli cell, the tail of the lambda will enter the E. coli bacterium. Nucleic acid (or the DNA), will then enter the bacterium through the lambda's tail.

    Infection

    • Infection of an E. coli cell occurs when lambda DNA is absorbed into the bacterium. Once the lambda DNA is absorbed by E. coli, the lambda DNA molecule will form a circular shape. This circular shape will prevent the lambda DNA from being destroyed by an E.coli cell. The lambda DNA will then begin to replicate in an initial phase known as Theta replication.

    Replication

    • Once Theta replication is initiated, lambda DNA copies will begin to be produced. As the lambda DNA is replicated, replications of the lambda DNA will begin to accumulate within an E. coli cell. Eventually the accumulation of lambda DNA will cause an E. coli cell to lyse, or break down. This results in the releasing of infected particles.

    Cell Death & Dormancy

    • Once an E.coli cell lyses and the lambda phages disperse, the E. coli cell will die. It is possible however, for Bacteriophage lambda to infect an E. coli cell and remain dormant. Given the right circumstances (such as ultraviolet lighting), a dormant lambda phage can leave dormancy and grow. Dormant lambda phages will then have the capacity to replicate their DNA and kill their E. coli host.

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