Myoviridae

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Myoviridae
Phage S-PM2.png
TEM Image of a Synechococcus Phage S-PM2 virion
Virus classification OOjs UI icon edit-ltr.svg
(unranked): Virus
Realm: Duplodnaviria
Kingdom: Heunggongvirae
Phylum: Uroviricota
Class: Caudoviricetes
Order: Caudovirales
Family:Myoviridae
Subfamilies and genera

see text

Myoviridae was a family of bacteriophages in the order Caudovirales . The family Myoviridae and order Caudovirales have now been abolished, with the term myovirus now used to refer to the morphology of viruses in this former family . Bacteria and archaea serve as natural hosts. There were 625 species in this family, assigned to eight subfamilies and 217 genera. [1] [2]

Contents

Subdivisions

The subfamily Tevenvirinae (synonym: Tequatrovirinae) 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 Tequatrovirus (Provisional name: T4virus) having a head length of 137 nm and those in the genus Schizot4virus 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 Bacillota . 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 known 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. [3]

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. [4] 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.

Virology

Typical structure of a myovirus Structure of a Myoviridae bacteriophage 2.jpg
Typical structure of a myovirus

Viruses in the former family Myoviridae are non-enveloped, with head-tail (with a neck) geometries. Genomes are linear, double-stranded DNA, around 33-244kb in length. The genome codes for 40 to 415 proteins. [1] It has terminally redundant sequences. The GC-content is ~35%. The genome encodes 200-300 proteins that are transcribed in operons. 5-Hydroxymethylcytosine may be present in the genome (instead of thymidine).

The tubular tail has helical symmetry and is 16-20 nm in diameter. It consists of a central tube, a contractile sheath, a collar, a base plate, six tail pins and six long fibers. It is similar to Tectiviridae , but differs in the fact that a myovirus' tail is permanent.

Contractions of the tail require ATP. On contraction of the sheath, sheath subunits slide over each other and the tail shortens to 10–15 nm in length.

Life cycle

Reproduction cycle of Pseudomonas bacteriophage PAK_P3, genus Nankokuvirus 118913 web phage PAK P3.jpg
Reproduction cycle of Pseudomonas bacteriophage PAK_P3, genus Nankokuvirus
Micrograph of a plastic thin section of a Salmonella cell with Phage SPN3US capsids lined up at the cell membrane. Scale bar: 2000 A. Credit: J. Bernard Heymann et al. (2020) Viruses-12-00910-g003 SPN3US edit.png
Micrograph of a plastic thin section of a Salmonella cell with Phage SPN3US capsids lined up at the cell membrane. Scale bar: 2000 Å. Credit: J. Bernard Heymann et al. (2020)

On attaching to a host cell, the virus uses its contractile sheath like a syringe, piercing the cell wall with its central tube and injecting the genetic material into the host. The injected DNA takes over the host cell's mechanisms for transcription and translation and begins to manufacture new viruses. Replication follows the replicative transposition model. DNA-templated transcription is the method of transcription. Translation takes place by -1 ribosomal frameshifting. The virus exits the host cell by lysis, and holin/endolysin/spanin proteins. Bacteria and archaea serve as the natural host. Transmission route is passive diffusion. [1]

Although Myoviruses are in general lytic, lacking the genes required to become lysogenic, a number of temperate species are known.

Applications

Because most Myoviridae are lytic, rather than temperate, phages, some researchers have investigated their use as a therapy for bacterial diseases in humans and other animals. [6]

Taxonomy

The following eight subfamilies are recognized: [2]

Additionally, the following genera are unassigned to a subfamily: [2]

Related Research Articles

<i>Podoviridae</i> Family of viruses

Podoviridae was a family of bacteriophage in the order Caudovirales often associated with T-7 like phages. The family and order Caudoviraleshave now been abolished, with the term podovirus now used to refer to the morphology of viruses in this former family. There were 130 species in this family, assigned to 3 subfamilies and 52 genera. This family was characterized by having very short, noncontractile tails. Many former phages in the former family Podoviriade are now classified in the Autographiviridae

<span class="mw-page-title-main">Caudovirales</span> Class of viruses

Caudoviricetes is a class of viruses known as the tailed bacteriophages. Under the Baltimore classification scheme, the Caudoviricetes are group I viruses as they have double stranded DNA (dsDNA) genomes, which can be anywhere from 18,000 base pairs to 500,000 base pairs in length. The virus particles have a distinct shape; each virion has an icosahedral head that contains the viral genome, and is attached to a flexible tail by a connector protein. The order encompasses a wide range of viruses, many containing genes of similar nucleotide sequence and function. However, some tailed bacteriophage genomes can vary quite significantly in nucleotide sequence, even among the same genus. Due to their characteristic structure and possession of potentially homologous genes, it is believed these bacteriophages possess a common origin.

<span class="mw-page-title-main">Cyanophage</span> Virus that infects cyanobacteria

Cyanophages are viruses that infect cyanobacteria, also known as Cyanophyta or blue-green algae. Cyanobacteria are a phylum of bacteria that obtain their energy through the process of photosynthesis. Although cyanobacteria metabolize photoautotrophically like eukaryotic plants, they have prokaryotic cell structure. Cyanophages can be found in both freshwater and marine environments. Marine and freshwater cyanophages have icosahedral heads, which contain double-stranded DNA, attached to a tail by connector proteins. The size of the head and tail vary among species of cyanophages. Cyanophages infect a wide range of cyanobacteria and are key regulators of the cyanobacterial populations in aquatic environments, and may aid in the prevention of cyanobacterial blooms in freshwater and marine ecosystems. These blooms can pose a danger to humans and other animals, particularly in eutrophic freshwater lakes. Infection by these viruses is highly prevalent in cells belonging to Synechococcus spp. in marine environments, where up to 5% of cells belonging to marine cyanobacterial cells have been reported to contain mature phage particles.

Punavirus is a genus of viruses in the order Caudovirales, in the family Myoviridae. Bacteria serve as natural hosts. There are four species in this genus.

Hpunavirus is a genus of viruses in the family Myoviridae, within the subfamily Peduovirinae. Bacteria serve as the natural host, with transmission achieved through passive diffusion. There are two species in this genus.

Peduovirus is a genus of viruses in the order Caudovirales, in the family Myoviridae, in the subfamily Peduovirinae. Bacteria serve as natural hosts, with transmission achieved through passive diffusion. There are 15 species in this genus.

Twortvirus is a genus of viruses in the order Caudovirales, in the family Herelleviridae, in the subfamily Twortvirinae. Bacteria serve as natural hosts. There is only one species in this genus: Staphylococcus virus Twort.

<i>Schizotequatrovirus</i> Genus of viruses

Schizotequatrovirus is a unassigned genus of viruses in the unassigned family Straboviridae, in the class Caudoviricetes,. Bacteria serve as natural hosts. There are three species in this genus.

Tequatrovirus is a genus of viruses in the order Caudovirales, in the family Myoviridae, in the subfamily Tevenvirinae. Gram-negative bacteria serve as the natural host, with transmission achieved through passive diffusion. There are 75 species in this genus.

Peduovirinae is a subfamily of viruses in the order Caudovirales, in the family Myoviridae. Bacteria serve as natural hosts. There are 76 species in this subfamily, assigned to 31 genera.

Felixounavirus is a genus of viruses in the order Caudovirales, in the family Myoviridae. Bacteria serve as natural hosts, with transmission achieved through passive diffusion. There are currently 16 species in this genus, including the type species Salmonella virus FelixO1.

<i>Tevenvirinae</i> Subfamily of viruses

Tevenvirinae is a subfamily of viruses in the order Caudovirales, in the family Myoviridae. Bacteria and archaea serve as natural hosts. There are 135 species in this subfamily, most included in 12 genera.

Hapunavirus is a genus of viruses in the family Myoviridae, not assigned to a subfamily. Bacteria serve as the natural host, with transmission achieved through passive diffusion. There are two species in this genus.

Muvirus is a genus of viruses in the order Caudovirales, in the family Myoviridae. Bacteria serve as natural hosts, with transmission achieved through passive diffusion. There are two species in this genus.

Lubbockvirus is a genus of viruses in the family Myoviridae, not assigned to a subfamily. Bacteria serve as the natural host, with transmission achieved through passive diffusion. There are two species in this genus.

Myohalovirus is a genus of viruses in the order Caudovirales, in the family Myoviridae. Bacteria and archaea serve as natural hosts. There are three species in this genus.

<i>Phikzvirus</i> Genus of viruses

Phikzvirus is a genus of viruses in the order Caudovirales, in the family Myoviridae. Bacteria serve as natural hosts. There are three species in this genus.

<i>Teseptimavirus</i> Genus of viruses

Teseptimavirus is a genus of viruses in the order Caudovirales, in the family Autographiviridae, in the subfamily Studiervirinae. Bacteria serve as the natural host, with transmission achieved through passive diffusion. There are currently 17 species in this genus, including the type species Escherichia virus T7.

Mycobacterium virus D29 (D29) is a cluster A mycobacteriophage belonging to the Siphoviridae family of viruses, it was discovered in 1954 by S. Froman. D29 is notable for its ability to infect M. tuberculosis. D29 is a double stranded DNA mycobacteriophage. It is a lytic phage, this means that D29 takes the lytic pathway of infection instead of the lysogenic pathway of infection. There are no human associated diseases associated with mycobacterium virus D29.

Escherichia virus CC31, formerly known as Enterobacter virus CC31, is a dsDNA bacteriophage of the subfamily Tevenvirinae responsible for infecting the bacteria family of Enterobacteriaceae. It is one of two discovered viruses of the genus Karamvirus, diverging away from the previously discovered T4virus, as a clonal complex (CC). CC31 was first isolated from Escherichia coli B strain S/6/4 and is primarily associated with Escherichia, even though is named after Enterobacter.

References

  1. 1 2 3 "Viral Zone". ExPASy. Retrieved 1 July 2015.
  2. 1 2 3 "Virus Taxonomy: 2020 Release". International Committee on Taxonomy of Viruses (ICTV). March 2021. Retrieved 11 May 2021.
  3. ↑ Tang, SL; Nuttall, S; Dyall-Smith, M (2004). "Haloviruses HF1 and HF2: evidence for a recent and large recombination event". J Bacteriol. 186 (9): 2810–7. doi:10.1128/JB.186.9.2810-2817.2004. PMC   387818 . PMID   15090523.
  4. ↑ Comeau, AM; Tremblay, D; Moineau, S; Rattei, T; Kushkina, AI; Tovkach, FI; Krisch, HM; Ackermann, HW (2012). "Phage morphology recapitulates phylogeny: the comparative genomics of a new group of myoviruses". PLOS ONE. 7 (7): e40102. Bibcode:2012PLoSO...740102C. doi: 10.1371/journal.pone.0040102 . PMC   3391216 . PMID   22792219.
  5. ↑ J. Bernard Heymann, Bing Wang, William W. Newcomb, Weimin Wu, Dennis C. Winkler, Naiqian Cheng, Erin R. Reilly, Ru-Ching Hsia, Julie A. Thomas, Alasdair C. Steven: The Mottled Capsid of the Salmonella Giant Phage SPN3US, a Likely Maturation Intermediate with a Novel Internal Shell. In: Viruses 2020, 12(9). Special Issue Giant or Jumbo Phages, 910. doi:10.3390/v12090910.
  6. ↑ Capparelli, Rosanna; et al. (August 2007). "Experimental phage therapy against Staphylococcus aureus in mice". Antimicrobial Agents and Chemotherapy. 51 (8): 2765–73. doi:10.1128/AAC.01513-06. PMC   1932491 . PMID   17517843.

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