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Virosphere
Virosphere (virus diversity, virus world, global virosphere) is the viral part of the biosphere, namely the pool of viruses in all hosts and all environments on planet earth. Virosphere may also refer to a pool of certain group of viruses according to their host - prokaryotic virosphere, archaeal virosphere, Invertebrate virosphere, type of genome - RNA virosphere, dsDNA virosphere or ecological niche - marine virosphere Viral genome diversity The scope of viral genome diversity is enormous compared to cellular life. Cellular life including all known organisms have double stranded DNA genome. Whereas viruses have one of at least 7 different types of genetic information, namely dsDNA, ssDNA, dsRNA, ssRNA+, ssRNA-, ssRNA-RT, dsDNA-RT. Each type of genetic information has its specific manner of mRNA synthesis. Baltimore classification is a system providing overview on these mechanisms for each type of genome. Moreover, in contrast to cellular organisms, viruses don't have uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898,Dimmock p. 4 more than 9,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, or ''virions'', consisting of (i) the genetic material, i. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baltimore Classification
Baltimore classification is a system used to classify viruses based on their manner of messenger RNA (mRNA) synthesis. By organizing viruses based on their manner of mRNA production, it is possible to study viruses that behave similarly as a distinct group. Seven Baltimore groups are described that take into consideration whether the viral genome is made of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA), whether the genome is single- or double-stranded, and whether the sense of a single-stranded RNA genome is positive or negative. Baltimore classification also closely corresponds to the manner of replicating the genome, so Baltimore classification is useful for grouping viruses together for both transcription and replication. Certain subjects pertaining to viruses are associated with multiple, specific Baltimore groups, such as specific forms of translation of mRNA and the host range of different types of viruses. Structural characteristics such as the shape of the vir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Domain (biology)
In biological taxonomy, a domain ( or ) (Latin: ''regio''), also dominion, superkingdom, realm, or empire, is the highest taxonomic rank of all organisms taken together. It was introduced in the three-domain system of taxonomy devised by Carl Woese, Otto Kandler and Mark Wheelis in 1990. According to the domain system, the tree of life consists of either three domains such as Archaea, Bacteria, and Eukarya, or two domains consisting of Archaea and Bacteria, with Eukarya included in Archaea. The first two are all prokaryotes, single-celled microorganisms without a membrane-bound nucleus. All organisms that have a cell nucleus and other membrane-bound organelles are included in Eukarya. Non-cellular life is not included in this system. Alternatives to the three-domain system include the earlier two-empire system (with the empires Prokaryota and Eukaryota), and the eocyte hypothesis (with two domains of Bacteria and Archaea, with Eukarya included as a branch of Archaea). Term ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guttaviridae
''Guttaviridae'' is a family of viruses. Archaea serve as natural hosts. There are two genera in this family, containing one species each. The name is derived from the Latin ''gutta'', meaning 'droplet'.Mochizuki T, Sako Y, Prangishvili D (2011) Provirus induction in hyperthermophilic Archaea: Characterization of Aeropyrum pernix spindle-shaped virus 1 and Aeropyrum pernix ovoid virus 1. J Bacteriol 193(19):5412–5419Arnold HP, Ziese U and Zillig W (2000). SNDV, a novel virus of the extremely thermophilic and acidophilic archaeon ''Sulfolobus''. Virology 272:409–16. Taxonomy The family contains the following genera and species: * ''Alphaguttavirus'' ** ''Sulfolobus newzealandicus droplet-shaped virus'' * ''Betaguttavirus'' ** ''Aeropyrum pernix ovoid virus 1'' Structure Viruses in the family ''Guttaviridae'' are enveloped. The diameter is around 70–95 nm, with a length of 110–185 nm. Genomes are circular, around 20kb in length. The virons consist of a coat, a co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ampullaviridae
''Ampullaviridae'' is a family of viruses that infect archaea of the genus '' Acidianus''. Only one genus in this family has been described, ''Bottigliavirus'', which contains three species. The name of the family and genus is derived from the Latin word for bottle, ''ampulla'', due to the virions having the shape of a bottle. The family was first described during an investigation of the microbial flora of hot springs in Italy. Taxonomy The family contains one genus, which has three species: * Genus: ''Bottigliavirus'', previously named ''Ampullavirus'' ** ''Bottigliavirus ABV'', previously named ''Acidianus bottle-shaped virus'' ** ''Bottigliavirus ABV2'' ** ''Bottigliavirus ABV3'' Structure and genome Ampullaviruses have unique morphology, with the virions being bottle-shaped with one narrow end that smoothly expands into a wider end for an overall length of about 230 nm and width of about 75 nm at the broad end. The narrow end projects beyond the viral envelope and is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fuselloviridae
''Fuselloviridae'' is a family of viruses. Sulfolobus species, specifically shibatae, solfataricus, and islandicus, serve as natural hosts. There are two genera and nine species in the family. The ''Fuselloviridae'' are ubiquitous in high-temperature (≥70 °C), acidic (pH ≤4) hot spring A hot spring, hydrothermal spring, or geothermal spring is a spring produced by the emergence of geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow bodies of magma (molten rock) or by c ...s around the world. Taxonomy The family contains the following genera and species: * '' Alphafusellovirus'' ** '' Sulfolobus spindle-shaped virus 1'' ** '' Sulfolobus spindle-shaped virus 2'' ** '' Sulfolobus spindle-shaped virus 4'' ** '' Sulfolobus spindle-shaped virus 5'' ** '' Sulfolobus spindle-shaped virus 7'' ** '' Sulfolobus spindle-shaped virus 8'' ** '' Sulfolobus spindle-shaped virus 9'' * '' Betafusellovirus'' ** '' Acidianus s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halspiviridae
''Halspiviridae'' is a family of viruses that consists of a single genus, ''Salterprovirus'', which consists of a single recognised species; ''Salterprovirus His1'' (hereafter, 'His1'). This virus was isolated from hypersaline water in Australia and was able to be cultured on the halophilic archaeon ''Haloarcula hispanica''. Like many other archaeoviruses, His1 has an approximately limoniform (lemon-shaped) virion. Etymology The family name, ''Halspiviridae'', is derived from halophilic and spindle-shaped, in reference to the habitat and virion morphology, respectively. The genus name, ''Salterprovirus'', is derived from salty terminal protein virus, as the linear dsDNA genome has proteins attached to the 5′ termini. Taxonomy The virion has a spindle-shaped morphology and is similar in shape to that of viruses infecting thermophilic archaea, the ''Fuselloviridae'', and His1 was originally described as a probable member of that group. However, it was later found that ther ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bicaudaviridae
''Bicaudaviridae'' is a family of hyperthermophilic archaeal viruses. Members of the genus ''Acidianus'' serve as natural hosts. There is only one genus (''Bicaudavirus'') and one species in this family: ''Acidianus two-tailed virus''. However, Sulfolobus tengchongensis spindle-shaped viruses 1 and 2 ( STSV1 and STSV2) are regarded to belong to this family also. Taxonomy The genus contains one genus, which contains one species: * ''Bicaudavirus'' ** ''Acidianus two-tailed virus'' Structure Viruses in ''Bicaudaviridae'' are non-enveloped, with lemon-shaped geometries. Genomes are circular dsDNA molecules of around 48–76 kb in length. High-resolution structure was determined by cryo-EM for Sulfolobus monocaudavirus 1 (SMV1) and a lower-resolution structure was determined for Acidianus two-tailed virus (ATV). Virions of both viruses have helical symmetry, with continuous 7-start helices, composed of the single major capsid protein, forming both the tails and the spindle-shaped b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Icosahedral Symmetry
In mathematics, and especially in geometry, an object has icosahedral symmetry if it has the same symmetries as a regular icosahedron. Examples of other polyhedra with icosahedral symmetry include the regular dodecahedron (the dual of the icosahedron) and the rhombic triacontahedron. Every polyhedron with icosahedral symmetry has 60 rotational (or orientation-preserving) symmetries and 60 orientation-reversing symmetries (that combine a rotation and a reflection), for a total symmetry order of 120. The full symmetry group is the Coxeter group of type . It may be represented by Coxeter notation and Coxeter diagram . The set of rotational symmetries forms a subgroup that is isomorphic to the alternating group on 5 letters. Description Icosahedral symmetry is a mathematical property of objects indicating that an object has the same symmetries as a regular icosahedron. As point group Apart from the two infinite series of prismatic and antiprismatic symmetry, rotati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capsid
A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The proteins making up the capsid are called capsid proteins or viral coat proteins (VCP). The capsid and inner genome is called the nucleocapsid. Capsids are broadly classified according to their structure. The majority of the viruses have capsids with either helical or icosahedral structure. Some viruses, such as bacteriophages, have developed more complicated structures due to constraints of elasticity and electrostatics. The icosahedral shape, which has 20 equilateral triangular faces, approximates a sphere, while the helical shape resembles the shape of a spring, taking the space of a cylinder but not being a cylinder itself. The capsid faces may consist of one or more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myohalovirus
''Myohalovirus'' (synonym: ''PhiH-like viruses'', ''Phihlikevirus'') 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. Taxonomy The following three species are assigned to the genus: * '' Halobacterium virus ChaoS9'' * '' Halobacterium virus phiH'' * '' Natrialba virus PhiCh1'' Structure Myohaloviruses are nonenveloped, with a head and tail. The head is icosahedral with a diameter of about 64 nm. The tail is around 170 nm long, 18 nm wide, has short terminal fibers, and is contractile. Genome Genomes are circular, around 59kb in length. The genome codes for 100 proteins. Life cycle Viral replication is cytoplasmic. The virus attaches to the host cell using its terminal fibers, and ejects the viral DNA into the host cytoplasm via contraction of its tail sheath. DNA-templated transcription is the method of transcription. Once the viral genes have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psimunavirus
''Psimunavirus'' (synonyms ''psiM-like viruses'', ''psiM1-like viruses'', ''Psimunalikevirus'') is a genus of viruses in the family ''Siphoviridae''. Bacteria and archaea serve as the natural host, with transmission achieved through passive diffusion. There is only one species in this genus: ''Psimunavirus psiM2''. Structure Psimunaviruses are nonenveloped, with a head and tail. The head is about 55 nm in diameter. The tail is long and flexible, at about 210 nm long, 10 nm wide, and has a terminal knob. Genome ''Psimunavirus'' is currently unlisted by NCBI. Life cycle Viral replication is cytoplasmic. The virus attaches to the host cell's adhesion receptors using its terminal fibers, and ejects the viral DNA into the host cytoplasm vilong flexible tail ejection system Replication follows the replicative transposition model. DNA-templated transcription is the method of transcription. Once the viral genes have been replicated, the procapsid is assembled and packed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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