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Pelamoviroid
The ''Avsunviroidae'' are a family of viroids. There are five species in three genera ('' Avsunviroid'', '' Elaviroid'' and '' Pelamoviroid''). They consist of RNA genomes between 246 and 375 nucleotides in length. They are single-stranded covalent circles and have intramolecular base pairing. All members lack a central conserved region. Replication Replication occurs in the chloroplasts of plant cells. Key features of replication include no helper virus required and no proteins are encoded for. Unlike the other family of viroids, ''Pospiviroidae'', ''Avsunviroidae'' are thought to replicate via a symmetrical rolling mechanism. It is thought the positive RNA strand acts as a template to form negative strands with the help of an enzyme thought to be RNA polymerase plus 3 II. The negative RNA strands are then cleaved by ribozyme activity and circularises. A second rolling circle mechanism forms a positive strand which is also cleaved by ribozyme activity and then ligated to becom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viroids
Viroids are small single-stranded, circular RNAs that are infectious pathogens. Unlike viruses, they have no protein coating. All known viroids are inhabitants of angiosperms (flowering plants), and most cause diseases, whose respective economic importance to humans varies widely. A recent metatranscriptomics study suggests that the host diversity of viroids and viroid-like elements is broader than previously thought and that it would not be limited to plants, encompassing even the prokaryotes. The first discoveries of viroids in the 1970s triggered the historically third major extension of the biosphere—to include smaller lifelike entities—after the discoveries in 1675 by Antonie van Leeuwenhoek (of the "subvisible" microorganisms) and in 1892–1898 by Dmitri Iosifovich Ivanovsky and Martinus Beijerinck (of the "submicroscopic" viruses). The unique properties of viroids have been recognized by the International Committee on Taxonomy of Viruses, in creating a new o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peach Latent Mosaic Viroid
''Peach latent mosaic viroid'' (binomial name ''Pelamoviroid latenspruni'') is a species of the genus ''Pelamoviroid'', which belongs to the family ''Avsunviroidae''. This family is characterized as having chloroplastic viroids with hammerhead ribozymes. Peach latent mosaic viroid is a 336-351 nt circular RNA which has a branched formation. This branched formation is stabilised by a pseudoknot between two kissing loops. Peach latent mosaic viroid was first described in the 1980s in Spain by a group of scientists. It is present in all peach- and nectarine-producing areas of the world including Europe, Asia, North America and South America and the frequency of naturally occurring infection is high. Before the development of symptoms the disease is latent in peach trees for approximately 5–7 years. The symptoms of the disease include necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelamoviroid
The ''Avsunviroidae'' are a family of viroids. There are five species in three genera ('' Avsunviroid'', '' Elaviroid'' and '' Pelamoviroid''). They consist of RNA genomes between 246 and 375 nucleotides in length. They are single-stranded covalent circles and have intramolecular base pairing. All members lack a central conserved region. Replication Replication occurs in the chloroplasts of plant cells. Key features of replication include no helper virus required and no proteins are encoded for. Unlike the other family of viroids, ''Pospiviroidae'', ''Avsunviroidae'' are thought to replicate via a symmetrical rolling mechanism. It is thought the positive RNA strand acts as a template to form negative strands with the help of an enzyme thought to be RNA polymerase plus 3 II. The negative RNA strands are then cleaved by ribozyme activity and circularises. A second rolling circle mechanism forms a positive strand which is also cleaved by ribozyme activity and then ligated to becom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elaviroid
The ''Avsunviroidae'' are a family of viroids. There are five species in three genera (''Avsunviroid'', ''Elaviroid'' and ''Pelamoviroid''). They consist of RNA genomes between 246 and 375 nucleotides in length. They are single-stranded covalent circles and have intramolecular base pairing. All members lack a central conserved region. Replication Replication occurs in the chloroplasts of plant cells. Key features of replication include no helper virus required and no proteins are encoded for. Unlike the other family of viroids, ''Pospiviroidae'', ''Avsunviroidae'' are thought to replicate via a symmetrical Rolling circle replication, rolling mechanism. It is thought the positive RNA strand acts as a template to form negative strands with the help of an enzyme thought to be RNA polymerase plus 3 II. The negative RNA strands are then cleaved by ribozyme activity and circularises. A second rolling circle mechanism forms a positive strand which is also cleaved by ribozyme activity a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avsunviroid
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] |
Annual Review Of Phytopathology
The ''Annual Review of Phytopathology'' is a peer-reviewed academic journal that publishes review articles about phytopathology, the study of diseases that affect plants. It was first published in 1963 as the result of a collaboration between the American Phytopathological Society and the nonprofit publisher Annual Reviews. As of 2024, ''Journal Citation Reports'' lists the journal's 2023 impact factor as 9.1, ranking it tenth of 265 journal titles in the category "Plant Sciences". As of 2023, it is being published as open access, under the Subscribe to Open model. Its current editors are John M. McDowell and Gwyn A. Beattie. History In the 1950s, the American Phytopathological Society had intended to publish its own journal to cover significant developments in the field of phytopathology, or plant diseases. However, the nonprofit publisher Annual Reviews offered to publish the journal for them, and they agreed due to their publishing experience. In 1961, the American Phyt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chrysanthemum Chlorotic Mottle Viroid
Chrysanthemums ( ), sometimes called mums or chrysanths, are flowering plants in the Asteraceae family. They are native to East Asia and northeastern Europe. Most species originate from East Asia, and the center of diversity is in China. Countless horticultural varieties and cultivars exist. Description The genus ''Chrysanthemum'' are perennial herbaceous flowering plants, sometimes subshrubs. The leaves are alternate, divided into leaflets and may be pinnatisect, lobed, or serrate (toothed) but rarely entire; they are connected to stalks with hairy bases. The compound inflorescence is an array of several flower heads, or sometimes a solitary head. The head has a base covered in layers of phyllaries. The simple row of ray florets is white, yellow, or red. The disc florets are yellow. Pollen grains are approximately 34 microns. The fruit is a ribbed achene. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Appler Hammerhead Viroid
Appler is a surname. Notable people with the surname include: *Barton Appler Bean (1860–1947), American ichthyologist * Johann Appler (1892–1978), German Nazi politician *Kathleen Appler Kathleen Mary Appler D.C (23 February 1952 – 18 March 2020) was an American Roman Catholic nun and member of the Daughters of Charity of Saint Vincent de Paul. She was one of the first seven women appointed members of the Congregation for Insti ..., American Roman Catholic nun See also * Appler-Englar House is a historic home located at united states, freedom county, merica {{Surname ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eggplant Latent Viroid
Eggplant ( US, CA, AU, PH), aubergine ( UK, IE, NZ), brinjal ( IN, SG, MY, ZA, SLE), or baigan ( IN, GY) is a plant species in the nightshade family Solanaceae. ''Solanum melongena'' is grown worldwide for its edible fruit, typically used as a vegetable in cooking. Most commonly purple, the spongy, absorbent fruit is used in several cuisines. It is a berry by botanical definition. As a member of the genus ''Solanum'', it is related to the tomato, chili pepper, and potato, although those are of the Americas region while the eggplant is of the Eurasia region. Like the tomato, its skin and seeds can be eaten, but it is usually eaten cooked. Eggplant is nutritionally low in macronutrient and micronutrient content, but the capability of the fruit to absorb oils and flavors into its flesh through cooking expands its use in the culinary arts. It was originally domesticated from the wild nightshade species ''thorn'' or ''bitter apple'', '' S. incanum'',Tsao and Lo in "Ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribozyme
Ribozymes (ribonucleic acid enzymes) are RNA molecules that have the ability to Catalysis, catalyze specific biochemical reactions, including RNA splicing in gene expression, similar to the action of protein enzymes. The 1982 discovery of ribozymes demonstrated that RNA can be both genetic material (like DNA) and a biological catalyst (like protein enzymes), and contributed to the RNA world hypothesis, which suggests that RNA may have been important in the evolution of prebiotic self-replicating systems. The most common activities of natural or Directed evolution, ''in vitro'' evolved ribozymes are the cleavage (or Ligation (molecular biology), ligation) of RNA and DNA and peptide bond formation. For example, the smallest ribozyme known (GUGGC-3') can aminoacylate a GCCU-3' sequence in the presence of PheAMP. Within the ribosome, ribozymes function as part of the large subunit ribosomal RNA to link amino acids during Translation (biology), protein synthesis. They also participate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hammerhead Ribozyme
The hammerhead ribozyme is an RNA Sequence motif, motif that catalyzes reversible cleavage and Ligation (molecular biology), ligation reactions at a specific site within an RNA molecule. It is one of several catalytic RNAs (ribozymes) known to occur in nature. It serves as a model system for research on the Nucleic acid structure, structure and properties of RNA, and is used for targeted RNA cleavage experiments, some with proposed therapeutic applications. Named for the resemblance of early Nucleic acid secondary structure, secondary structure diagrams to a hammerhead shark, hammerhead ribozymes were originally discovered in two classes of plant virus-like RNAs: Satellite (biology), satellite RNAs and viroids. They are also known in some classes of retrotransposons, including the retrozymes. The hammerhead ribozyme motif has been ubiquitously reported in lineages across the Tree of life (biology), tree of life. The self-cleavage reactions, first reported in 1986, are part of a ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
