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Duplopiviricetes
''Durnavirales'' is an order of double-stranded RNA viruses which infect eukaryotes. The name of the group derives from Italian ''duplo'' which means double (a reference to double-stranded), ''rna'' for the type of virus, and -''virales'' which is the suffix for a virus order. Families The following families are recognized: * '' Amalgaviridae'' * '' Curvulaviridae'' * ''Hypoviridae'' * ''Partitiviridae ''Partitiviridae'' is a family of double-stranded RNA viruses. Plants, fungi, and protozoa serve as natural hosts. It has been suggested that they can also infect bacteria. The name comes from the Latin ''partitius,'' which means divided, and ...'' * '' Picobirnaviridae'' References Viruses {{Virus-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double-stranded RNA Viruses
Double-stranded RNA viruses (dsRNA viruses) are a polyphyletic group of viruses that have double-stranded genomes made of ribonucleic acid. The double-stranded genome is used to transcribe a positive-strand RNA by the viral RNA-dependent RNA polymerase (RdRp). The positive-strand RNA may be used as messenger RNA (mRNA) which can be translated into viral proteins by the host cell's ribosomes. The positive-strand RNA can also be replicated by the RdRp to create a new double-stranded viral genome. Double-stranded RNA viruses are classified in two separate phyla ''Duplornaviricota'' and ''Pisuviricota'' (specifically class ''Duplopiviricetes''), which are in the kingdom ''Orthornavirae'' and realm ''Riboviria''. The two groups do not share a common dsRNA virus ancestor. Double-stranded RNA viruses evolved two separate times from positive-strand RNA viruses. In the Baltimore classification system, dsRNA viruses belong to Group III. Virus group members vary widely in host range (anim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryote
Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacteria and Archaea (both prokaryotes) make up the other two domains. The eukaryotes are usually now regarded as having emerged in the Archaea or as a sister of the Asgard archaea. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among archaea. Eukaryotes represent a small minority of the number of organisms, but, due to their generally much larger size, their collective global biomass is estimated to be about equal to that of prokaryotes. Eukaryotes emerged approximately 2.3–1.8 billion years ago, during the Proterozoic eon, likely as flagellated phagotrophs. Their name comes from the Greek εὖ (''eu'', "well" or "good") and κάρυον (''karyon'', "nut" or "kernel"). Euka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus Classification
Virus classification is the process of naming viruses and placing them into a taxonomic system similar to the classification systems used for cellular organisms. Viruses are classified by phenotypic characteristics, such as morphology, nucleic acid type, mode of replication, host organisms, and the type of disease they cause. The formal taxonomic classification of viruses is the responsibility of the International Committee on Taxonomy of Viruses (ICTV) system, although the Baltimore classification system can be used to place viruses into one of seven groups based on their manner of mRNA synthesis. Specific naming conventions and further classification guidelines are set out by the ICTV. A catalogue of all the world's known viruses has been proposed and, in 2013, some preliminary efforts were underway. Definitions Species definition Species form the basis for any biological classification system. Before 1982, it was thought that viruses could not be made to fit Ernst Mayr's r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amalgaviridae
''Amalgaviridae'' is a family of double-stranded RNA viruses. Member viruses infect plants and are transmitted vertically via seeds. The name derives from ''amalgam'' (blend, mix) which refers to amalgaviruses possessing characteristics of both partitiviruses and totiviruses. There are ten species in the family. Genome Amalgavirus genomes are monopartite and about 3.5 kilobases in length. They have two partially overlapping open reading frames which encode the RNA-dependent RNA polymerase (RdRp) and a putative capsid protein. Evolution It has been suggested that amalgaviruses have evolved via recombination between viruses with double-stranded and negative-strand RNA genomes. Phylogenetic analysis indicates that the amalgavirus RdRp forms a sister clade to the corresponding RdRp protein of partitiviruses (''Partitiviridae'') which have segmented (bipartite) dsRNA genomes and infect plants, fungi and protists. By contrast, the putative capsid protein of amalgaviruses is homo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoviridae
''Hypovirus'' is a genus of viruses, in the family ''Hypoviridae''. Fungi serve as natural hosts. There are four species in this genus. Infection reduces the virulence of its parasitic host, making it a hyperparasite useful for blight control. Species The following species are recognized by the ICTV, all of which were found with ''Cryphonectria parasitica'': *'' Cryphonectria hypovirus 1'' *'' Cryphonectria hypovirus 2'' *'' Cryphonectria hypovirus 3'' *'' Cryphonectria hypovirus 4'' There are numerous family members affecting other plant-pathogenic fungi not yet accepted into the ICTV nomenclature. A proposal reorganizes the family into three genera. The informal family '' Fusariviridae'' is the sister group. Structure The diameter is around 50–80 nm. Genomes are linear, around 9–13kb in length. The genome has 1 or 2 open reading frames, named OrfA (not always present) and OrfB. The genome contains no structural proteins. The virus accordingly does not bud out of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Partitiviridae
''Partitiviridae'' is a family of double-stranded RNA viruses. Plants, fungi, and protozoa serve as natural hosts. It has been suggested that they can also infect bacteria. The name comes from the Latin ''partitius,'' which means divided, and refers to the segmented genome of partitiviruses. There are five genera and 60 species in the family, 15 of which are unassigned to a genus. Structure Viruses in the family ''Partitiviridae'' are non-enveloped with icosahedral geometries and T=1 symmetry. The diameter of partitiviruses is around 25–43 nm. Genome Partitiviruses have double-stranded RNA genomes divided into two genomic segments, and there may be additional subgenomic segments. The two genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding g ... segments are package ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picobirnaviridae
''Picobirnavirus'' is a genus of double-stranded RNA viruses. It is the only genus in the family ''Picobirnaviridae''. Although amniotes, especially mammals, were thought to serve as hosts, it has been recently suggested that these viruses might infect bacteria and possibly some other invertebrates. There are three species in this genus. Associated symptoms include gastroenteritis in animals and humans, though the disease association is unclear. Etymology Picobirnavirus is a small (''pico'', Spanish for ''small''), bisegmented (''bi'', Latin for ''two''), double-stranded RNA virus. Picobirnaviruses were initially considered to be birna-like viruses, and the name was derived from birnavirus (bisegmented RNA), but the virions are much smaller (diameter 35 nm vs. 65 nm). Picobirnaviruses were first detected in humans and black-footed pigmy rice rats in 1988. Structure Viruses in the genus are non-enveloped, with icosahedral geometries, and T=3 symmetry. The diameter is around 35 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
