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Pithovirus
''Alphapithovirus'', is a genus of giant virus known from two species, '' Alphapithovirus sibericum'', which infects amoebas, and '' Alphapithovirus massiliense''. It is DNA-based and is a member of the nucleocytoplasmic large DNA viruses clade. It was discovered in 2014, when a viable specimen was found in a 30,000-year-old ice core harvested from permafrost in Siberia, Russia. Description The genus name ''Alphapithovirus'', a reference to large storage containers of ancient Greece known as pithoi, was chosen to describe the new species. A specimen of ''Alphapithovirus'' measures approximately 1.5 μm (1500 nm) in length and 0.5 μm (500 nm) in diameter, making it one of the largest viruses yet found, second to Megaklothovirus. It is 50% larger in size than the '' Pandoraviridae'', the previous largest-known viruses, and is larger than '' Ostreococcus'', the smallest eukaryotic cell, although ''Pandoravirus'' has the largest viral genome, containing 1.9 to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alphapithovirus Sibericum
''Alphapithovirus'', is a genus of giant virus known from two species, '' Alphapithovirus sibericum'', which infects amoebas, and '' Alphapithovirus massiliense''. It is DNA-based and is a member of the nucleocytoplasmic large DNA viruses clade. It was discovered in 2014, when a viable specimen was found in a 30,000-year-old ice core harvested from permafrost in Siberia, Russia. Description The genus name ''Alphapithovirus'', a reference to large storage containers of ancient Greece known as pithoi, was chosen to describe the new species. A specimen of ''Alphapithovirus'' measures approximately 1.5 μm (1500 nm) in length and 0.5 μm (500 nm) in diameter, making it one of the largest viruses yet found, second to Megaklothovirus. It is 50% larger in size than the ''Pandoraviridae'', the previous largest-known viruses, and is larger than ''Ostreococcus'', the smallest eukaryotic cell, although ''Pandoravirus'' has the largest viral genome, containing 1.9 to 2.5 m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alphapithovirus Massiliense
''Alphapithovirus'', is a genus of giant virus known from two species, ''Alphapithovirus sibericum'', which infects amoebas, and '' Alphapithovirus massiliense''. It is DNA-based and is a member of the nucleocytoplasmic large DNA viruses clade. It was discovered in 2014, when a viable specimen was found in a 30,000-year-old ice core harvested from permafrost in Siberia, Russia. Description The genus name ''Alphapithovirus'', a reference to large storage containers of ancient Greece known as pithoi, was chosen to describe the new species. A specimen of ''Alphapithovirus'' measures approximately 1.5 μm (1500 nm) in length and 0.5 μm (500 nm) in diameter, making it one of the largest viruses yet found, second to Megaklothovirus. It is 50% larger in size than the ''Pandoraviridae'', the previous largest-known viruses, and is larger than ''Ostreococcus'', the smallest eukaryotic cell, although ''Pandoravirus'' has the largest viral genome, containing 1.9 to 2.5 me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleocytoplasmic Large DNA Viruses
''Nucleocytoviricota'' is a phylum of viruses. Members of the phylum are also known as the nucleocytoplasmic large DNA viruses (NCLDV), which serves as the basis of the name of the phylum with the suffix - for virus phylum. These viruses are referred to as nucleocytoplasmic because they are often able to replicate in both the host's cell nucleus and cytoplasm. The phylum is notable for containing the giant viruses. There are nine families of NCLDVs that all share certain genomic and structural characteristics; however, it is uncertain whether the similarities of the different families of this group have a common viral ancestor. One feature of this group is a large genome and the presence of many genes involved in DNA repair, DNA replication, transcription, and translation. Typically, viruses with smaller genomes do not contain genes for these processes. Most of the viruses in this family also replicate in both the host's nucleus and cytoplasm, thus the name nucleocytoplasmic. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pandoravirus
''Pandoravirus'' is a proposed genus of giant virus, first discovered in 2013. It is the third largest in physical size of any known viral genus, behind Pithovirus and Megaklothovirus. Pandoraviruses have double stranded DNA genomes, with the largest genome size (2.5 million base pairs) of any known viral genus. Discovery The discovery of Pandoraviruses by a team of French scientists, led by husband and wife Jean-Michel Claverie and Chantal Abergel, was announced in a report in the journal ''Science'' in July 2013. Other scientists had previously observed the pandoravirus particles, but owing to their enormous size they were not expected to be viruses. Patrick Scheid, a parasitologist from the Central Institute of the Bundeswehr Medical Service in Koblenz, Germany, found one in 2008, in an amoeba living in the contact lens of a woman with keratitis. Its development within the amoebal host was documented extensively. Unlike in other cases with such giant viruses, the l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pandoraviridae
''Pandoraviridae'' is a proposed family of double-stranded DNA viruses that infect amoebae. There is only one genus in this family: ''Pandoravirus''. Several species in this genus have been described, including '' Pandoravirus dulcis'', '' Pandoravirus salinus'' and '' Pandoravirus yedoma''. History The viruses were discovered in 2013. Description The viruses in this family are the second largest known virus (~1 micrometer) in capsid length, after ''Pithovirus'' (1.5 micrometer). ''Pandoravirus'' has the largest viral genome known, containing double-stranded DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ... of 1.9 to 2.5 megabase pairs. Evolution These viruses appear to be related to the phycodnaviruses. References {{Taxonbar, from=Q16987267 Nucleocytoplasmic larg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giant Virus
A giant virus, sometimes referred to as a girus, is a very large virus, some of which are larger than typical bacteria. All known giant viruses belong to the phylum ''Nucleocytoviricota''. Description While the exact criteria as defined in the scientific literature vary, giant viruses are generally described as viruses having large, pseudo-Capsid#Icosahedral, icosahedral capsids (200 to 400 nanometers in diameter) that may be surrounded by a thick (approximately 100 nm) layer of filamentous protein fibers. The viruses have large, double-stranded DNA genomes (300 to >1000 kilobasepairs) that encode a large contingent of genes (of the order of 1000 genes). The best characterized giant viruses are the phylogenetically related mimivirus and megavirus, which belong to the family ''Mimiviridae'' (aka ''Megaviridae''), and are distinguished by their large capsid diameters. Giant viruses from the deep ocean, terrestrial sources, and human patients contain genes encoding Cytochrome P4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permafrost
Permafrost () is soil or underwater sediment which continuously remains below for two years or more; the oldest permafrost has been continuously frozen for around 700,000 years. Whilst the shallowest permafrost has a vertical extent of below a meter (3 ft), the deepest is greater than . Similarly, the area of individual permafrost zones may be limited to narrow mountain summits or extend across vast Arctic regions. The ground beneath glaciers and ice sheets is not usually defined as permafrost, so on land, permafrost is generally located beneath a so-called active layer of soil which freezes and thaws depending on the season. Around 15% of the Northern Hemisphere or 11% of the global surface is underlain by permafrost, covering a total area of around . This includes large areas of Alaska, Canada, Greenland, and Siberia. It is also located in high mountain regions, with the Tibetan Plateau being a prominent example. Only a minority of permafrost exists in the Southern Hemi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megaviridae
''Mimiviridae'' is a family of viruses. Amoeba and other protists serve as natural hosts. The family contains three subfamilies that contain nine genera., UCPMS ID: 1889607PDF/ref> Fig. 4 and §Discussion: "Considering that tupanviruses comprise a sister group to amoebal mimiviruses..." Viruses in this family belong to the nucleocytoplasmic large DNA virus clade (NCLDV), also referred to as giant viruses. History The first member of this family, Mimivirus, was discovered in 2003, and the first complete genome sequence was published in 2004. However, the mimivirus Cafeteria roenbergensis virus was isolated and partially characterized in 1995, although the host was misidentified at the time, and the virus was designated BV-PW1. Taxonomy The family contains the following subfamilies and genera (-''virinae'' denotes subfamily and -''virus'' denotes genus): * '' Aliimimivirinae'' ** '' Rheavirus'' * '' Klosneuvirinae'' ** '' Fadolivirus'' ** '' Theiavirus'' ** '' Yasminevirus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iridoviridae
''Iridoviridae'' is a family of viruses with double-stranded DNA genomes. Amphibians, fish, and invertebrates such as arthropods serve as natural hosts. There are currently 22 species in this family, divided among two subfamilies and seven genera. Nomenclature The name is derived from Iris, the Greek goddess of the rainbow. This name was chosen because of the "rainbow-like" iridescence observed in heavily infected insects and pelleted samples of invertebrate iridoviruses. Taxonomy The following subfamilies and genera are recognized (-''virinae'' denotes subfamily and -''virus'' denotes genus): * '' Alphairdovirinae'' ** '' Lymphocystivirus'' ** '' Megalocytivirus'' ** '' Ranavirus'' * '' Betairidovirinae'' ** '' Chloriridovirus'' ** '' Daphniairidovirus'' ** '' Decapodiridovirus'' ** '' Iridovirus'' Structure The virions are icosahedral with triangulation number (T) = 189–217, 120–350 nm in diameter and made up of three domains: an outer proteinaceous capsid, an int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Icosahedron
In geometry, an icosahedron ( or ) is a polyhedron with 20 faces. The name comes . The plural can be either "icosahedra" () or "icosahedrons". There are infinitely many non- similar shapes of icosahedra, some of them being more symmetrical than others. The best known is the ( convex, non- stellated) regular icosahedron—one of the Platonic solids—whose faces are 20 equilateral triangles. Regular icosahedra There are two objects, one convex and one nonconvex, that can both be called regular icosahedra. Each has 30 edges and 20 equilateral triangle faces with five meeting at each of its twelve vertices. Both have icosahedral symmetry. The term "regular icosahedron" generally refers to the convex variety, while the nonconvex form is called a ''great icosahedron''. Convex regular icosahedron The convex regular icosahedron is usually referred to simply as the ''regular icosahedron'', one of the five regular Platonic solids, and is represented by its Schläfli symbol , contai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base Pair
A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA and RNA. Dictated by specific hydrogen bonding patterns, "Watson–Crick" (or "Watson–Crick–Franklin") base pairs (guanine–cytosine and adenine–thymine) allow the DNA helix to maintain a regular helical structure that is subtly dependent on its nucleotide sequence. The Complementarity (molecular biology), complementary nature of this based-paired structure provides a Redundancy (information theory), redundant copy of the genetic information encoded within each strand of DNA. The regular structure and data redundancy provided by the DNA double helix make DNA well suited to the storage of genetic information, while base-pairing between DNA and incoming nucleotides provides the mechanism through which DNA polymerase replicates DNA and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GC-content
In molecular biology and genetics, GC-content (or guanine-cytosine content) is the percentage of nitrogenous bases in a DNA or RNA molecule that are either guanine (G) or cytosine (C). This measure indicates the proportion of G and C bases out of an implied four total bases, also including adenine and thymine in DNA and adenine and uracil in RNA. GC-content may be given for a certain fragment of DNA or RNA or for an entire genome. When it refers to a fragment, it may denote the GC-content of an individual gene or section of a gene (domain), a group of genes or gene clusters, a non-coding region, or a synthetic oligonucleotide such as a primer. Structure Qualitatively, guanine (G) and cytosine (C) undergo a specific hydrogen bonding with each other, whereas adenine (A) bonds specifically with thymine (T) in DNA and with uracil (U) in RNA. Quantitatively, each GC base pair is held together by three hydrogen bonds, while AT and AU base pairs are held together by two hydrogen bonds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
