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Avsunviroid
The ''Avsunviroidae'' are a family of viroids. There are four 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 become ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avsunviroid
The ''Avsunviroidae'' are a family of viroids. There are four 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 become ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelamoviroid
The ''Avsunviroidae'' are a family of viroids. There are four 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 become ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elaviroid
The ''Avsunviroidae'' are a family of viroids. There are four 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. 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 order of subviral agents. The first recognized viroid, the pathogenic agent of the potato spindle tuber disease, was discovered, initially molecularly characterized, and named by Theodor Otto Diener, plant pathologist a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peach Latent Mosaic Viroid
''Peach latent mosaic viroid'' 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 336-351Nucleotide, 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, 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 of buds, delayed shoot development, necrotic branches, premature ageing of trees, flower streaking, ripening deformations, enlarged rounded stones, circular discolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rolling Circle Replication
Rolling circle replication (RCR) is a process of unidirectional nucleic acid replication that can rapidly synthesize multiple copies of circular molecules of DNA or RNA, such as plasmids, the genomes of bacteriophages, and the circular RNA genome of viroids. Some eukaryotic viruses also replicate their DNA or RNA via the rolling circle mechanism. As a simplified version of natural rolling circle replication, an isothermal DNA amplification technique, rolling circle amplification was developed. The RCA mechanism is widely used in molecular biology and biomedical nanotechnology, especially in the field of biosensing (as a method of signal amplification). Circular DNA replication Rolling circle DNA replication is initiated by an initiator protein encoded by the plasmid or bacteriophage DNA, which nicks one strand of the double-stranded, circular DNA molecule at a site called the double-strand origin, or DSO. The initiator protein remains bound to the 5' phosphate end of the ni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avocado Sunblotch Viroid
Avocado sunblotch viroid (ASBV) 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 inherently only evaluates as positiv . ... [...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 2022, ''Journal Citation Reports'' lists the journal's 2021 impact factor as 10.850, ranking it seventh of 238 journal titles in the category "Plant Sciences". Its current editors are Jan E. Leach and Steven E. Lindow. 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 Phytopathological Society compiled the editorial board of the journal at their annual meeting. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chrysanthemum Chlorotic Mottle Viroid
Chrysanthemums (), sometimes called mums or chrysanths, are flowering plants of the genus ''Chrysanthemum'' in the family Asteraceae. They are native to East Asia and northeastern Europe. Most species originate from East Asia and the center of diversity is in China.Liu, P. L., et al. (2012)Phylogeny of the genus ''Chrysanthemum'' L.: Evidence from single-copy nuclear gene and chloroplast DNA sequences.''PLOS One'' 7(11), e48970. . Countless horticultural varieties and cultivars exist. Description The genus ''Chrysanthemum'' are perennial herbaceous flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...s, sometimes subshrubs. The leaves are alternate, divided into leaflets and may be pinnatisect, lobed, or serrate (toothed) but rarely entire. The compound inf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Appler Hammerhead Viroid
Appler is a surname. Notable people with the surname include: *Barton Appler Bean Barton Appler Bean was an American ichthyologist, born May 21, 1860 in Lancaster County, Pennsylvania and died June 16, 1947 in Chemung, New York, after falling from a bridge. He was the brother of the ichthyologist Tarleton Hoffman Bean (1846-1 ... (1860–1947), American ichthyologist * Johann Appler (1892–1978), German Nazi politician * Kathleen Appler, American Roman Catholic nun See also * Appler-Englar House, is a historic home located at New Windsor, Carroll County, Maryland {{Surname ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eggplant Latent Viroid
Eggplant ( US, Canada), aubergine ( UK, Ireland) or brinjal (Indian subcontinent, Singapore, Malaysia, South Africa) is a plant species in the nightshade family Solanaceae. ''Solanum melongena'' is grown worldwide for its edible fruit. Most commonly purple, the spongy, absorbent fruit is used in several cuisines. Typically used as a vegetable in cooking, 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 New World while the eggplant is of the Old World. Like the tomato, its skin and seeds can be eaten, but, like the potato, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribozyme
Ribozymes (ribonucleic acid enzymes) are RNA molecules that have the ability to 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 catalysis, 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 in vitro-evolved ribozymes are the cleavage or 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 in a variety of RNA processing reactions, including RNA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
