Team:LCG-UNAM-Mexico/Resources/Virus

Bacteriophages used in the defense system

 * Bacteriophage T7: It is a phage capable of infecting susceptible bacterial cells. It infects most strains of Escherichia coli (including E. coli O157:H7) which don’t have flagella. The virus is said to have complex structural symmetry, with a capsid of the phage that is spherical with an inner diameter of 55 nm and a tail 19 nm in diameter and 28.5 nm long attached to the capsid. The head of the phage particle contains the roughly 40 kbp dsDNA genome of T7[1]. This phage is considered a lytic phage with a lytic cycle that spans 12 to 15 minutes [2].  It is reported that for every infection around 200 hundred phages are produced [3].


 * Bacteriophage T3: It is a bacteriophage of the genus T7-like phages, of the family Podoviridae, which is very closely related to Bacteriophage T7[4].

Bacteriophagues used in the delivery system

 * P2 and P4 bacteriophagues: Extracellularly, P4 may be found as a virion capable of injecting its own DNA into Escherichia coli and other gram-negative bacteria. Most of the proteins that make up its capsid and tail, however, are encoded by a helper bacteriophage of the P2 family, since the P4 genome lacks information for these  structural proteins and for the lysis of the host cell.  The P4 and P2  genomes contains approximatey 11.6Kb and 33.8Kb. Both genomes are double stranded linear molecules and they circularize after injection into the host[5].