Search results
Results from the WOW.Com Content Network
Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome, and may have structures that are either simple or elaborate. Their genomes may encode as few as four genes (e.g. MS2) and as many as hundreds of genes. Phages replicate within the bacterium following the injection of their genome into its cytoplasm.
Lambda phage DNA injection into the cell membrane using Mannose PTS permease (a sugar transporting system) as a mechanism of entry into the cytoplasm Host DNA gyrase puts negative supercoils in the circular chromosome, causing A-T-rich regions to unwind and drive transcription.
Phage injecting its genome into bacterial cell An electron micrograph of bacteriophages attached to a bacterial cell. These viruses are the size and shape of coliphage T1. Phage therapy, viral phage therapy, or phagotherapy is the therapeutic use of bacteriophages for the treatment of pathogenic bacterial infections.
Attachment – the phage attaches itself to the surface of the host cell in order to inject its DNA into the cell; Penetration – the phage injects its DNA into the host cell by penetrating through the cell membrane; Transcription – the host cell's DNA is degraded and the cell's metabolism is directed to initiate phage biosynthesis
The best studied example includes the bacteriophages; for example, when the tail fibers of the T2 phage land on a cell, its central sheath pierces the cell membrane and the phage injects DNA from the head capsid directly into the cell. [17]
In order for the T-even phage to infect its host and begin its life cycle it must enter the first process of infection, adsorption of the phage to the bacterial cell. Adsorption is a value characteristic of phage-host pair and the adsorption of the phage on host cell surface is illustrated as a 2-stage process: reversible and irreversible.
The phage particle adsorbs onto the surface of the bacterium using the tail fibers for specificity. The tail sheath contracts and the DNA of the phage is injected into the host cell. The host DNA recombination machinery or the cre enzyme translated from the viral DNA recombine the terminally redundant ends and circularize the genome.
Bacteriophage P2 is a temperate phage, which means that it can propagate lytically (i.e. directing the host cell to produce phage progenies and finally lysing the host when the phage progenies exit), as well as establish lysogeny (i.e. injecting and fusing its genetic material into the genome of the host without lysing the cell) and maintain as ...