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Negative-sense, Single-stranded RNA Virus
Negative-strand RNA viruses (−ssRNA viruses) are a group of related viruses that have negative-sense, single-stranded genomes made of ribonucleic acid. They have genomes that act as complementary strands from which messenger RNA (mRNA) is synthesized by the viral enzyme RNA-dependent RNA polymerase (RdRp). During replication of the viral genome, RdRp synthesizes a positive-sense antigenome that it uses as a template to create genomic negative-sense RNA. Negative-strand RNA viruses also share a number of other characteristics: most contain a viral envelope that surrounds the capsid, which encases the viral genome, −ssRNA virus genomes are usually linear, and it is common for their genome to be segmented. Negative-strand RNA viruses constitute the phylum ''Negarnaviricota'', in the kingdom '' Orthornavirae'' and realm '' Riboviria''. They are descended from a common ancestor that was a double-stranded RNA (dsRNA) virus, and they are considered to be a sister clade of reovi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission Electron Micrograph
Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a grid. An image is formed from the interaction of the electrons with the sample as the beam is transmitted through the specimen. The image is then magnified and focused onto an imaging device, such as a fluorescent screen, a layer of photographic film, or a sensor such as a scintillator attached to a charge-coupled device. Transmission electron microscopes are capable of imaging at a significantly higher resolution than light microscopes, owing to the smaller de Broglie wavelength of electrons. This enables the instrument to capture fine detail—even as small as a single column of atoms, which is thousands of times smaller than a resolvable object seen in a light microscope. Transmission electron microscopy is a major analytical method i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthornavirae
''Orthornavirae'' is a kingdom of viruses that have genomes made of ribonucleic acid (RNA), those genomes encoding an RNA-dependent RNA polymerase (RdRp). The RdRp is used to transcribe the viral RNA genome into messenger RNA (mRNA) and to replicate the genome. Viruses in this kingdom also share a number of characteristics involving evolution, including high rates of genetic mutations, recombinations, and reassortments. Viruses in ''Orthornavirae'' belong to the realm ''Riboviria''. They are descended from a common ancestor that may have been a non-viral molecule that encoded a reverse transcriptase instead of an RdRp for replication. The kingdom is subdivided into five phyla that separate member viruses based on their genome type, host range, and genetic similarity. Viruses with three genome types are included: positive-strand RNA viruses, negative-strand RNA viruses, and double-stranded RNA viruses. Many of the most widely known viral diseases are caused by RNA viruses in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lassa Fever Virus
''Lassa mammarenavirus'' (LASV) is an arenavirus that causes Lassa hemorrhagic fever, a type of viral hemorrhagic fever (VHF), in humans and other primates. ''Lassa mammarenavirus'' is an emerging virus and a select agent, requiring Biosafety Level 4-equivalent containment. It is endemic in West African countries, especially Sierra Leone, the Republic of Guinea, Nigeria, and Liberia, where the annual incidence of infection is between 300,000 and 500,000 cases, resulting in 5,000 deaths per year. As of 2012 discoveries within the Mano River region of west Africa have expanded the endemic zone between the two known Lassa endemic regions, indicating that LASV is more widely distributed throughout the tropical wooded savannah ecozone in west Africa. There are no approved vaccines against Lassa fever for use in humans. Discovery In 1969, missionary nurse Laura Wine fell ill with a mysterious disease she contracted from an obstetrical patient in Lassa, a village in Borno S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Influenza Virus
''Orthomyxoviridae'' (from Greek ὀρθός, ''orthós'' 'straight' + μύξα, ''mýxa'' 'mucus') is a family of negative-sense RNA viruses. It includes seven genera: ''Alphainfluenzavirus'', ''Betainfluenzavirus'', '' Gammainfluenzavirus'', '' Deltainfluenzavirus'', ''Isavirus'', ''Thogotovirus'', and ''Quaranjavirus''. The first four genera contain viruses that cause influenza in birds (see also avian influenza) and mammals, including humans. Isaviruses infect salmon; the thogotoviruses are arboviruses, infecting vertebrates and invertebrates (such as ticks and mosquitoes). The Quaranjaviruses are also arboviruses, infecting vertebrates (birds) and invertebrates (arthropods). The four genera of Influenza virus that infect vertebrates, which are identified by antigenic differences in their nucleoprotein and matrix protein, are as follows: * ''Alphainfluenzavirus'' infects humans, other mammals, and birds, and causes all flu pandemics * ''Betainfluenzavirus'' infects huma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hantavirus
''Orthohantavirus'' is a genus of single-stranded, enveloped, negative-sense RNA viruses in the family '' Hantaviridae'' within the order ''Bunyavirales''. Members of this genus may be called orthohantaviruses or simply hantaviruses. Orthohantaviruses typically cause chronic asymptomatic infection in rodents. Humans may become infected with hantaviruses through contact with rodent urine, saliva, or feces. Some strains cause potentially fatal diseases in humans, such as hantavirus hemorrhagic fever with renal syndrome (HFRS), or hantavirus pulmonary syndrome (HPS), also known as hantavirus cardiopulmonary syndrome (HCPS), while others have not been associated with known human disease (e.g. Prospect Hill virus). HPS (HCPS) is a "rare respiratory illness associated with the inhalation of aerosolized rodent excreta (urine and feces) contaminated by hantavirus particles." Human infections of hantaviruses have almost entirely been linked to human contact with rodent excrement; howe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ebola Virus
''Zaire ebolavirus'', more commonly known as Ebola virus (; EBOV), is one of six known species within the genus '' Ebolavirus''. Four of the six known ebolaviruses, including EBOV, cause a severe and often fatal hemorrhagic fever in humans and other mammals, known as Ebola virus disease (EVD). Ebola virus has caused the majority of human deaths from EVD, and was the cause of the 2013–2016 epidemic in western Africa, which resulted in at least suspected cases and confirmed deaths. Ebola virus and its genus were both originally named for Zaire (now the Democratic Republic of the Congo), the country where it was first described, and was at first suspected to be a new "strain" of the closely related Marburg virus. The virus was renamed "Ebola virus" in 2010 to avoid confusion. Ebola virus is the single member of the species ''Zaire ebolavirus'', which is assigned to the genus '' Ebolavirus'', family '' Filoviridae'', order '' Mononegavirales''. The members of the species are ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tomato Spotted Wilt Virus
Transmission and lifespan TSWV, which is transmitted by thrips, causes serious losses in economically important crops and it is one of the most economically devastating plant viruses in the world. The circulative propagative transmission of TSWV is carried out by at least ten different species of thrips. The most common species is ''Frankliniella occidentalis'' (western flower thrips) as it is the vector that predominantly transmits TSWV globally and in greenhouses. The rapid developmental and reproductive rate of the thrips contributes to the spread of TSWV. The amount of time it takes for insects to acquire the virus (acquisition period) and the amount of time it takes for the virus to move from the insect to the plant (inoculation) for TSWV varies depends on the vector species. For ''Frankliniella occidentalis'', the acquisition and inoculation of TSWV can be as short as 5 minutes. However, the acquisition and inoculation periods for optimal transmission is 21.3 hours and 4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rift Valley Fever Virus
In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben with normal faulting and rift-flank uplifts mainly on one side. Where rifts remain above sea level they form a rift valley, which may be filled by water forming a rift lake. The axis of the rift area may contain volcanic rocks, and active volcanism is a part of many, but not all, active rift systems. Major rifts occur along the central axis of most mid-ocean ridges, where new oceanic crust and lithosphere is created along a divergent boundary between two tectonic plates. ''Failed rifts'' are the result of continental rifting that failed to continue to the point of break-up. Typically the transition from rifting to spreading develops at a triple junction where three converging rifts meet over a hotspot. Two of these evolve to the point o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, often mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages. Arthropods are bilaterally symmetrical and their body possesses an external skeleton. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. Some species have wings. They are an extremely diverse group, with up to 10 million species. The haemocoel, an arthropod's internal cavity, through which its haemolymph – analogue of blood – circulates, accommodates its interior organs; it has an open circulatory system. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. Their nervous system is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cap Snatching
The first step of transcription for some negative, single-stranded RNA viruses is cap snatching, in which the first 10 to 20 residues of a host cell RNA are removed (snatched) and used as the 5′ cap and primer to initiate the synthesis of the nascent viral mRNA. The viral RNA-dependent RNA polymerase (RdRp) can then proceed to replicate the negative-sense genome from the positive-sense template. Cap-snatching also explains why some viral mRNA have 5’ terminal extensions of 10-20 nucleotides that are not encoded for in the genome. Examples of viruses that engage in cap-snatching include influenza viruses (''Orthomyxoviridae''), Lassa virus ('' Arenaviridae''), hantaan virus (''Hantaviridae'') and rift valley fever virus (''Phenuiviridae''). Most viruses snatch 15-20 nucleotides except for the families ''Arenaviridae'' and ''Nairoviridae'' and the genus Thogotovirus (''Orthomyxoviridae'') which use a shorter strand. In the influenza virus, cap snatching occurs in the nucleus of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyploviricotina
''Polyploviricotina'' is a subphylum of viruses in the phylum ''Negarnaviricota''. It is one of only two virus subphyla, the other being '' Haploviricotina'', which is also in ''Negarnaviricota''. The name comes from , the Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ... for 'complex', along with the suffix for a virus subphylum; 'viricotina'. References External links Invasion of the Body Snatchers: Viruses Can Steal Our Genetic Code to Create New Human-Virus Genes on: SciTechDaily, Source: Mount Sinai School of Medicine; August 9, 2020 * Jessica Sook Yuin Ho, Matthew Angel, Yixuan Ma, Jonathan W. Yewdell, Edward Hutchinson, Ivan Marazzi, ''et al.''Hybrid Gene Origination Creates Human-Virus Chimeric Proteins during Infection in: Cell Volume 181, Issue 7 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haploviricotina
''Haploviricotina'' is a subphylum of viruses in the phylum ''Negarnaviricota''. It is one of only two virus subphyla, the other being ''Polyploviricotina'', which is also in ''Negarnaviricota''. The name comes from , the Ancient Greek for 'simple', along with the suffix for a virus subphylum; 'viricotina'. Taxonomy The subphylum ''Haploviricotina'' is composed of 4 classes and 5 orders: * '' Chunqiuviricetes'' ** '' Muvirales'' * '' Milneviricetes'' ** '' Serpentovirales'' * '' Monjiviricetes'' ** '' Jingchuvirales'' ** ''Mononegavirales ''Mononegavirales'' is an order of negative-strand RNA viruses which have nonsegmented genomes. Some common members of the order are Ebola virus, human respiratory syncytial virus, measles virus, mumps virus, Nipah virus, and rabies virus. A ...'' * '' Yunchangviricetes'' ** '' Goujianvirales'' References Negarnaviricota Virus subphyla {{Virus-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
