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List Of Subviral Agents ...
Subviral agents are pathogenic entities that can cause disease, but lack various fundamental properties of viruses. Subviral agents consist of satellites, viroids, prions, defective interfering particles, viriforms, and, most recently, obelisks. See also * List of prions * Virus classification References {{reflist subviral agents 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pathogenic
In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term ''pathogen'' came into use in the 1880s. Typically, the term ''pathogen'' is used to describe an ''infectious'' microorganism or agent, such as a virus, bacterium, protozoan, prion, viroid, or fungus. Small animals, such as helminths and insects, can also cause or transmit disease. However, these animals are usually referred to as parasites rather than pathogens. The scientific study of microscopic organisms, including microscopic pathogenic organisms, is called microbiology, while parasitology refers to the scientific study of parasites and the organisms that host them. There are several pathways through which pathogens can invade a host. The principal pathways have different episodic time frames, but soil has the longest or most pers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sputnik Virophage
Sputnik virophage (from Russian "satellite") is a subviral agent that reproduces in amoeba cells that are already infected by a certain helper virus; Sputnik uses the helper virus's machinery for reproduction and inhibits replication of the helper virus. It is known as a virophage, in analogy to the term ''bacteriophage''. Viruses like Sputnik that depend on co-infection of the host cell by helper viruses are known as satellite viruses. At its discovery in a Paris water-cooling tower in 2008, Sputnik was the first known satellite virus that inhibited replication of its helper virus and thus acted as a parasite of that virus. In analogy, it was called a '' virophage''. Sputnik virophages were found infecting giant viruses of '' Mimiviridae'' group A. However, they are able to grow in amoebae infected by ''Mimiviridae'' of any of the groups A, B, and C. Virology Sputnik was first isolated in 2008 from a sample obtained from humans; it was harvested from the contact lens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avocado Sunblotch Viroid
Avocado sunblotch viroid (ASBV, ''Avsunviroid albamaculaperseae'') is a disease affecting avocado trees. Infections result in lower yields and poorer quality fruit. ASBV is the smallest known viroid that infects plants and is transmitted by pollen and infected seeds or budwood. Trees infected with the viroid often show no symptoms other than a reduction in yield, (by 30% or more). However, they are still carriers and can pass the disease onto other plants. Symptoms in more serious infections include depressed longitudinal streaks of yellow in the fruit. The fruit may also become red or white in colour. Symptoms in the leaf are uncommon but include bleached veins and petioles. Rectangular cracking patterns also occur in the bark of older branches. The amount (titre Titer (American English) or titre (British English) is a way of expressing concentration. Titer testing employs serial dilution to obtain approximate quantitative information from an analytical procedure that inh ... [...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 virus genomic component inside the capsid, along with occasionally present virus core protein, is called the virus core. The capsid and core together are referred to as a nucleocapsid (cf. also virion). 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 th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virusoid
Virusoids are circular single-stranded RNA(s) dependent on viruses for replication and encapsidation. The genome of virusoids consists of several hundred (200–400) nucleotides and does not code for any proteins. Virusoids are essentially viroids that have been encapsulated by a helper virus coat protein. They are thus similar to viroids in their means of replication (rolling circle replication) and in their lack of genes, but they differ in that viroids do not possess a protein coat. Both virusoids and a few viroids encode a hammerhead ribozyme. Virusoids, while being studied in virology, are subviral particles rather than viruses. Since they depend on helper viruses, they are classified as satellites. Virusoids are listed in virological taxonomy as Satellites/Satellite nucleic acids/Subgroup 3: Circular satellite RNA(s). Definition Depending on whether a lax or strict definition is used, the term ''virusoid'' may also include Hepatitis D virus (HDV). Like plant vir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tolecusatellitidae
''Tolecusatellitidae'' is a ''incertae sedis or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...'' ssDNA/ssDNA(+) family of biological satellites. The family contains two genera and 131 species. This family of viruses depend on the presence of another virus ( helper viruses) to replicate their genomes, as such they have minimal genomes with very low genomic redundancy. Name The name ''Tolecusatellitidae'' is a combination of ''Tolecu'', from the first DNA satellite shown to be associated with ''To''mato ''le''af ''cu''rl virus and ''satellite'', the fact that it is a satellite. Taxonomy The species are ssDNA unless specified ssDNA(+). There are 62 ssDNA(+) and 69 ssDNA satellites. Betasatellite * Ageratum leaf curl Buea betasatellite * Ageratum leaf curl Cameroon betasatel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alphasatellite
''Alphasatellites'' are a single-stranded DNA family of satellite viruses that depend on the presence of another virus (helper viruses) to replicate their genomes. As such, they have minimal genomes with very low genomic redundancy. The genome is a single circular single strand DNA molecule. The first alphasatellites were described in 1999 and were associated with cotton leaf curl disease and Ageratum yellow vein disease. As begomoviruses are being characterised at the molecular level an increasing number of alphasatellites are being described. These viruses were earlier known as DNA 1 components. These viruses are generally found in the Old World. A number have been isolated from the New World but their association with their host viruses is still being studied. Genome The genome is between 1300 and 1400 nucleotides in length and has three conserved features: a hairpin structure, a single open reading frame (ORF) and an adenine rich region. The hairpin structure has a loop tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yellowstone Lake Virophage
Yellowstone National Park is a national park of the United States located in the northwest corner of Wyoming, with small portions extending into Montana and Idaho. It was established by the 42nd U.S. Congress through the Yellowstone National Park Protection Act and signed into law by President Ulysses S. Grant on March 1, 1872. Yellowstone was the first national park in the US, and is also widely understood to be the first national park in the world. The park is known for its wildlife and its many geothermal features, especially the Old Faithful geyser, one of its most popular. While it represents many types of biomes, the subalpine forest is the most abundant. It is part of the South Central Rockies forests ecoregion. While Native Americans have lived in the Yellowstone region for at least 11,000 years, aside from visits by mountain men during the early-to-mid-19th century, organized exploration did not begin until the late 1860s. Management and control of the par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
