Picornaviruses
Last reviewed: 23.04.2024
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Picornaviruses (picornaviridae, from the use of pica - small) - a family of non-enveloped viruses containing single-stranded plus RNA.
The family has more than 230 representatives and consists of 9 genera: Enterovirus (11 serotypes), Rhinoviras (105 serotypes). Aphtovirus (7 serotypes), Heputoviras (2 serotypes: 1 person, 1 monkey), Cardiovirus (2 serotypes); Parechovinis, Erbovirus, Kobuvirus - the names of new genera. The genera consist of species, the species from serotypes. All these viruses can infect vertebrates.
[Structure of picornaviruses
Picornaviruses are small, simple, organized viruses. The diameter of the virus is about 30 nm. The virion consists of an icosahedral capsid. Surrounding the infectious one-stranded plus RNA with the VPg protein. The capsid consists of 12 pentamers (pentamers), each of which, in turn, consists of 5 protein subunit-protomers. The protomers are formed by 4 viral sex and peptides and: VP1, VP2, VP3, VP4. Proteins VP1, VP2 and VP3 are located on the surface of the virion, and VP4 - inside the viral particle.
Reproduction of picornaviruses
The virus interacts with receptors on the cell surface. With the help of these receptors, the viral genome is transferred to the cytoplasm, accompanied by the loss of VP4 and the release of viral RNA from the protein membrane. The genome of the virus can enter the cell by endocytosis, followed by the release of nucleic acid from the vacuole or by injection of RNA through the cytoplasmic membrane of the cell. At the end of RNA there is a viral protein - VPg. The genome is used, like RNA, for protein synthesis. One large polyprotein is translated from the viral genome. Then the polyprotein is split into individual viral proteins, including RNA-dependent polymerase, synthesizes the minus-strand matrix from the surface.
Structural proteins are collected in kaisid, the genome is incorporated into it, forming a virion. The time required for the complete cycle of reproduction - from infection to the end of the virus assembly - is usually 5-10 hours. Their value depends on factors such as pH, temperature, type of virus and host cell, metabolic state of the cell, number of particles, infected one cell. Virions are released from the cell by means of its lysis. Reproduction occurs in the cytoplasm of cells. In a culture under an agar coating, viruses form plaques.