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The ''Myoviridae'' is a family of bacteriophages in the order Caudovirales. Bacteria and archaea serve as natural hosts. There are currently 93 species in this family, divided among four subfamilies and 30 genera.〔(【引用サイトリンク】url=http://viralzone.expasy.org/all_by_species/140.html )〕〔(【引用サイトリンク】title=Virus Taxonomy: 2014 Release )〕 ==Subdivisions== The subfamily Tevenvirinae (synonym: Teequatrovirinae) is named after its type species ''Enterobacteria phage T4''. Members of this subfamily are morphologically indistinguishable and have moderately elongated heads of about 110 nanometers (nm) in length, 114 nm long tails with a collar, base plates with short spikes and six long kinked tail fibers. The genera within this subfamily are divided on the basis of head morphology with the genus ''T4likevirus'' having a head length of 137 nm and those in the genus ''Schizot4likevirus'' being 111 nm in length. Within the genera on the basis of protein homology the species have been divided into a number of groups. The subfamily Peduovirinae have virions with heads of 60 nm in diameter and tails of 135 × 18 nm. These phages are easily identified because contracted sheaths tend to slide off the tail core. The P" phage is the type species. The subfamily Spounavirinae are all virulent, broad-host range phages that infect members of the ''Firmicutes''. They possess isometric heads of 87-94 nm in diameter and conspicuous capsomers, striated 140-219 nm long tails and a double base plate. At the tail tip are globular structures now know to be the base plate spikes and short kinked tail fibers with six-fold symmetry. Members of this group usually possess large (127–142 kb) nonpermuted genomes with 3.1–20 kb terminal redundancies. The name for this subfamily is derived from SPO plus ''una'' (Latin for one). The haloviruses HF1 and HF2 belong to the same genus but since they infect archaea rather than bacteria are likely to be placed in a separate genus once their classification has been settled. A dwarf group has been proposed on morphological and genomic grounds. This group includes the phages Aeromonas salmonicida phage 56, Vibrio cholerae phages 138 and CP-T1, Bdellovibrio phage φ1422 and Pectobacterium carotovorum phage ZF40. Their shared characteristics include an identical virion morphology, characterized by usually short contractile tails and all have genome sizes of approximately 45 kilobases. The gene order in the structural unit of the genome is in the order: terminase—portal—head—tail—base plate—tail fibers. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「myoviridae」の詳細全文を読む スポンサード リンク
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