Twortlikevirus

Twortlikevirus is a genus in the family Myoviridae, within the sub-family Spounavirinae. Bacteria serve as the natural host, with transmission achieved through passive diffusion. There are currently five virus species in this genus, including the type species Staphylococcus phage Twort.^[1][2][3]

Virology

Viruses in this genus are nonenveloped, with a head and tail. The head is approximately 84 nm to 94 nm in diameter and T=16 symmetry. The tail is around 140 nm to 219 nm long, has 6 long terminal fibers, 6 short spikes, globular structures at the tip, and a double base plate. The tail is enclosed in a sheath, which loosens and slides around the tail core upon contraction.^[1]

Life cycle

The virus attaches to the host cell using its tail fibers, and ejects the viral DNA into the host cytoplasm via contraction of its tail sheath. Once the viral genes have been replicated, the procapsid is assembled and packed. The tail is then assembled and the mature virions are released via lysis.^[1]

History

The genus Twortlikevirus was first accepted as a new genus, at the same time as all five of its contained species as well as its containing sub-family Peduovirinae, in ICTV's 2010–11 report.^[2] The new genus was proposed in 2009.^[4]

Taxonomy

Species:

• Staphylococcus phage Twort
• Staphylococcus phage K
• Staphylococcus phage G1
• Listeria phage P100
• Listeria phage A511

Genome

Four of the five viruses' genomes have been fully sequenced and are available on NCBI's website (the only exception being Listeria phage P100). They range between 130k and 149k nucleotides, with 190 to 233 proteins. All four complete genomes, as well as several additional "unclassified" virus genomes, are available online.^[3]

References