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Strawberry Mottle Virus
Strawberry mottle virus (SMV) is a pathogenic plant virus in ''Secoviridae'', a family of plant-infecting picornaviruses. It is not yet assigned to a genus. Virions are isometric, approximately 28 nm in diameter, and contain two RNA strands (RNA1 and RNA2) equal to about 12,600 nucleotides in length. The polyprotein of RNA1 contains regions identified as helicase, protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the ..., RNA-dependent RNA polymerase and a viral genome-linked protein while RNA2 shows similarities to the large coat protein domain of the '' Satsuma dwarf virus''. References External links ICTVdB - The Universal Virus Database: Strawberry mottle virus (SMV)* ICTV Virus Taxonomy 200* UniProt Taxonom Secoviridae Viral strawberry diseases {{Viru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus Disease
A viral disease (or viral infection) occurs when an organism's body is invaded by pathogenic viruses, and infectious virus particles (virions) attach to and enter susceptible cells. Structural Characteristics Basic structural characteristics, such as genome type, virion shape and replication site, generally share the same features among virus species within the same family. * Double-stranded DNA families: three are non-enveloped (''Adenoviridae'', ''Papillomaviridae'' and ''Polyomaviridae'') and two are enveloped (''Herpesviridae'' and ''Poxviridae''). All of the non-enveloped families have icosahedral capsids. * Partly double-stranded DNA viruses: ''Hepadnaviridae''. These viruses are enveloped. * One family of single-stranded DNA viruses infects humans: ''Parvoviridae''. These viruses are non-enveloped. * Positive single-stranded RNA families: three non-enveloped (''Astroviridae'', ''Caliciviridae'' and ''Picornaviridae'') and four enveloped (''Coronaviridae'', ''Flaviviridae' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Virus
Plant viruses are viruses that affect plants. Like all other viruses, plant viruses are obligate intracellular parasites that do not have the molecular machinery to replicate without a host. Plant viruses can be pathogenic to higher plants. Most plant viruses are rod-shaped, with protein discs forming a tube surrounding the viral genome; isometric particles are another common structure. They rarely have an envelope. The great majority have an RNA genome, which is usually small and single stranded (ss), but some viruses have double-stranded (ds) RNA, ssDNA or dsDNA genomes. Although plant viruses are not as well understood as their animal counterparts, one plant virus has become very recognizable: ''tobacco mosaic virus'' (TMV), the first virus to be discovered. This and other viruses cause an estimated US$60 billion loss in crop yields worldwide each year. Plant viruses are grouped into 73 genera and 49 families. However, these figures relate only to cultivated plants, which r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secoviridae
''Secoviridae'' is a family of viruses in the order ''Picornavirales''. Plants serve as natural hosts. There are 8 genera and 86 species in this family, one of which is unassigned to a genus. The family was created in 2009 with the grouping of families ''Sequiviridae'', now dissolved, and ''Comoviridae'', now subfamily ''Comovirinae'', along with the then unassigned genera ''Cheravirus'', ''Sadwavirus'', and ''Torradovirus''. Taxonomy The family includes the following genera (-''virinae'' denotes subfamily and -''virus'' denotes genus): * ''Comovirinae ''Comovirinae'' is a subfamily of viruses in the order ''Picornavirales'', in the family ''Secoviridae''; its genera were formerly classified in the family ''Comoviridae''. Plants serve as natural hosts. There are 62 species in this subfamily, a ...'' ** '' Comovirus'' ** '' Fabavirus'' ** '' Nepovirus'' * Unassigned to a subfamily: ** '' Cheravirus'' ** '' Sadwavirus'' ** '' Sequivirus'' ** '' Torradovirus'' ** '' Waikavirus'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picornavirales
''Picornavirales'' is an order of viruses with vertebrate, invertebrate, protist and plant hosts. The name has a dual etymology. First, ''picorna-'' is an acronym for poliovirus, insensitivity to ether, coxsackievirus, orphan virus, rhinovirus, and ribonucleic acid. Secondly, pico-, meaning extremely small, combines with RNA to describe these very small RNA viruses. The order comprises viruses that historically are referred to as picorna-like viruses. Characteristics The families within this order share a number of common features: * The virions are non- enveloped, icosahedral, and about 30 nanometers in diameter. * The capsid has a "pseudo T=3" structure, and is composed of 60 protomers each made of three similar-sized but nonidentical beta barrels. * The genome is made of one or a few single-stranded RNA(s) serving directly as mRNA, without overlapping open reading frames. * The genome has a small protein, VPg, covalently attached to its 5' end, and usually a poly-adenylat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virion
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.e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicase
Helicases are a class of enzymes thought to be vital to all organisms. Their main function is to unpack an organism's genetic material. Helicases are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separating two hybridized nucleic acid strands (hence '' helic- + -ase''), using energy from ATP hydrolysis. There are many helicases, representing the great variety of processes in which strand separation must be catalyzed. Approximately 1% of eukaryotic genes code for helicases. The human genome codes for 95 non-redundant helicases: 64 RNA helicases and 31 DNA helicases. Many cellular processes, such as DNA replication, transcription, translation, recombination, DNA repair, and ribosome biogenesis involve the separation of nucleic acid strands that necessitates the use of helicases. Some specialized helicases are also involved in sensing of viral nucleic acids during infection and fulfill a immunological function. Function Helicases are o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protease
A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products. They do this by cleaving the peptide bonds within proteins by hydrolysis, a reaction where water breaks bonds. Proteases are involved in many biological functions, including digestion of ingested proteins, protein catabolism (breakdown of old proteins), and cell signaling. In the absence of functional accelerants, proteolysis would be very slow, taking hundreds of years. Proteases can be found in all forms of life and viruses. They have independently evolved multiple times, and different classes of protease can perform the same reaction by completely different catalytic mechanisms. Hierarchy of proteases Based on catalytic residue Proteases can be classified into seven broad groups: * Serine protease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNA-dependent RNA Polymerase
RNA-dependent RNA polymerase (RdRp) or RNA replicase is an enzyme that catalyzes the replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand complementary to a given RNA template. This is in contrast to typical DNA-dependent RNA polymerases, which all organisms use to catalyze the transcription of RNA from a DNA template. RdRp is an essential protein encoded in the genomes of most RNA-containing viruses with no DNA stage including SARS-CoV-2. Some eukaryotes also contain RdRps, which are involved in RNA interference and differ structurally from viral RdRps. History Viral RdRps were discovered in the early 1960s from studies on mengovirus and polio virus when it was observed that these viruses were not sensitive to actinomycin D, a drug that inhibits cellular DNA-directed RNA synthesis. This lack of sensitivity suggested that there is a virus-specific enzyme that could copy RNA from an RNA template and not from a DNA template. Distr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satsuma Dwarf Virus
''Sadwavirus'' is a genus of viruses in the order ''Picornavirales'', in the family ''Secoviridae''. Plants (specifically Satsuma (fruit), Satsuma mandarin trees) serve as natural hosts. There are three subgenera and five species in this genus. Diseases associated with this genus include: satsuma dwarf virus disease which causes spoon-shaped leaves on citrus tree. Symptoms are enations, multiple flushing, stunting or dwarfing, reduction in number and size of leaves and fruits. The name of this genus comes from one of its species: Satsuma dwarf virus. Taxonomy The following subgenera and species are recognized: * ''Cholivirus'' ** ''Chocolate lily virus A'' ** ''Dioscorea mosaic associated virus'' * ''Satsumavirus'' ** ''Satsuma dwarf virus'' * ''Stramovirus'' ** ''Black raspberry necrosis virus'' ** ''Strawberry mottle virus'' Structure Viruses in ''Sadwavirus'' are non-enveloped, with icosahedral geometries, and T=pseudo3 symmetry. The diameter is around 25-30 nm. The geno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
