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Fusion Mechanism
A fusion mechanism is any mechanism by which cell fusion or virus–cell fusion takes place, as well as the machinery that facilitates these processes. Cell fusion is the formation of a hybrid cell from two separate cells. There are three major actions taken in both virus–cell fusion and cell–cell fusion: the dehydration of polar head groups, the promotion of a hemifusion stalk, and the opening and expansion of pores between fusing cells. Virus–cell fusions occur during infections of several viruses that are health concerns relevant today. Some of these include HIV, Ebola, and influenza. For example, HIV infects by fusing with the membranes of immune system cells. In order for HIV to fuse with a cell, it must be able to bind to the receptors CD4, CCR5, and CXCR4. Cell fusion also occurs in a multitude of mammalian cells including gametes and myoblasts. Viral mechanisms Fusogens Proteins that allow viral or cell membranes to overcome barriers to fusion are called fusogen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Fusion
Cell fusion is an important cellular process in which several uninucleate cells (cells with a single nucleus) combine to form a multinucleate cell, known as a syncytium. Cell fusion occurs during differentiation of myoblasts, osteoclasts and trophoblasts, during embryogenesis, and morphogenesis. Cell fusion is a necessary event in the maturation of cells so that they maintain their specific functions throughout growth. History In 1847 Theodore Schwann expanded upon the theory that all living organisms are composed of cells when he added to it that discrete cells are the basis of life. Schwann observed that in certain cells the walls and cavities of the cells coalesce together. It was this observation that provided the first hint that cells fuse. It was not until 1960 that cell biologists deliberately fused cells for the first time. To fuse the cells, biologists combined isolated mouse cells, with the same kind of tissue, and induced fusion of their outer membrane using the Sendai v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Sheet
The beta sheet, (β-sheet) (also β-pleated sheet) is a common motif of the regular protein secondary structure. Beta sheets consist of beta strands (β-strands) connected laterally by at least two or three backbone hydrogen bonds, forming a generally twisted, pleated sheet. A β-strand is a stretch of polypeptide chain typically 3 to 10 amino acids long with backbone in an extended conformation. The supramolecular association of β-sheets has been implicated in the formation of the fibrils and protein aggregates observed in amyloidosis, notably Alzheimer's disease. History The first β-sheet structure was proposed by William Astbury in the 1930s. He proposed the idea of hydrogen bonding between the peptide bonds of parallel or antiparallel extended β-strands. However, Astbury did not have the necessary data on the bond geometry of the amino acids in order to build accurate models, especially since he did not then know that the peptide bond was planar. A refined versi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phospholipid
Phospholipids, are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids typically have omega-3 fatty acids EPA and DHA integrated as part of the phospholipid molecule. The phosphate group can be modified with simple organic molecules such as choline, ethanolamine or serine. Phospholipids are a key component of all cell membranes. They can form lipid bilayers because of their amphiphilic characteristic. In eukaryotes, cell membranes also contain another class of lipid, sterol, interspersed among the phospholipids. The combination provides fluidity in two dimensions combined with mechanical strength against rupture. Purified phospholipids are produced commercially and have found applications in nanotechnology and materials science. The first phospholipid identified in 1847 as such in biological tissues was lecith ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reovirus
''Reoviridae'' is a family of double-stranded RNA viruses. Member viruses have a wide host range, including vertebrates, invertebrates, plants, protists and fungi. They lack lipid envelopes and package their segmented genome within multi-layered capsids. Lack of a lipid envelope has allowed three-dimensional structures of these large complex viruses (diameter ∼60–100 nm) to be obtained, revealing a structural and likely evolutionary relationship to the cystovirus family of bacteriophage. There are currently 97 species in this family, divided among 15 genera in two subfamilies. Reoviruses can affect the gastrointestinal system (such as rotaviruses) and respiratory tract. The name "reo-" is an acronym for "''r''espiratory ''e''nteric ''o''rphan" viruses''.'' The term "orphan virus" refers to the fact that some of these viruses have been observed not associated with any known disease. Even though viruses in the family ''Reoviridae'' have more recently been identified with vario ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uukuniemi Virus
''Phlebovirus'' is one of twenty genera of the family ''Phenuiviridae'' in the order ''Bunyavirales''. The genus contains 66 species. It derives its name from Phlebotominae, the vectors of member species ''Naples phlebovirus'', which is said to be ultimately from the Greek , meaning "vein". The proper word for "vein" in ancient Greek is however ''phleps'' (φλέψ). Virology Phleboviruses are viruses with a negative-sense RNA genome consisting of three segments. The small segment (S) codes for the viral N protein and a non structural protein, NSs via an ambisense coding strategy. The medium-sized segment (M) codes for a precursor of the viral glycoproteins and non-structural components. The product of the largest segment (L) is the viral RNA-dependent RNA polymerase. Replication The Phlebovirus replicates in a 7 step process. First, the cellular attachment is driven through the glycoprotein interactions with host cells. Examples of this are Dendritic Cell-Specific Intercellu ... [...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] |
Phleboviruses
''Phlebovirus'' is one of twenty genera of the family ''Phenuiviridae'' in the order ''Bunyavirales''. The genus contains 66 species. It derives its name from Phlebotominae, the vectors of member species ''Naples phlebovirus'', which is said to be ultimately from the Greek , meaning "vein". The proper word for "vein" in ancient Greek is however ''phleps'' (φλέψ). Virology Phleboviruses are viruses with a negative-sense RNA genome consisting of three segments. The small segment (S) codes for the viral N protein and a non structural protein, NSs via an ambisense coding strategy. The medium-sized segment (M) codes for a precursor of the viral glycoproteins and non-structural components. The product of the largest segment (L) is the viral RNA-dependent RNA polymerase. Replication The Phlebovirus replicates in a 7 step process. First, the cellular attachment is driven through the glycoprotein interactions with host cells. Examples of this are Dendritic Cell-Specific Intercellu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rubella
Rubella, also known as German measles or three-day measles, is an infection caused by the rubella virus. This disease is often mild, with half of people not realizing that they are infected. A rash may start around two weeks after exposure and last for three days. It usually starts on the face and spreads to the rest of the body. The rash is sometimes itchy and is not as bright as that of measles. Swollen lymph nodes are common and may last a few weeks. A fever, sore throat, and fatigue may also occur. Joint pain is common in adults. Complications may include bleeding problems, testicular swelling, encephalitis, and inflammation of nerves. Infection during early pregnancy may result in a miscarriage or a child born with congenital rubella syndrome (CRS). Symptoms of CRS manifest as problems with the eyes such as cataracts, deafness, as well as affecting the heart and brain. Problems are rare after the 20th week of pregnancy. Rubella is usually spread from one person to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chikungunya
Chikungunya is an infection caused by the ''Chikungunya virus'' (CHIKV). Symptoms include fever and joint pains. These typically occur two to twelve days after exposure. Other symptoms may include headache, muscle pain, joint swelling, and a rash. Symptoms usually improve within a week; however, occasionally the joint pain may last for months or years. The risk of death is around 1 in 1,000. The very young, old, and those with other health problems are at risk of more severe disease. The virus is spread between people by two types of mosquitos: ''Aedes albopictus'' and ''Aedes aegypti''. They mainly bite during the day. The virus may circulate within a number of animals including birds and rodents. Diagnosis is by either testing the blood for the virus's RNA or antibodies to the virus. The symptoms can be mistaken for those of dengue fever and Zika fever. It is believed most people become immune after a single infection. The best means of prevention is overall mosquito contr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sindbis Virus
''Sindbis virus'' (SINV) is a member of the ''Togaviridae'' family, in the ''Alphavirus'' genus. The virus was first isolated in 1952 in Cairo, Egypt. The virus is transmitted by mosquitoes (''Culex'' and Culiseta). SINV is linked to Pogosta diseaseKurkela S, Manni T, Vaheri A, Vapalahti OCausative agent of Pogosta disease isolated from blood and skin lesions Emerg Infect Dis erial on the Internet Published 2004 May. (accessed 2007-10-16) (Finland), Ockelbo disease ( Sweden) and Karelian fever (Russia). In humans, the symptoms include arthralgia, rash and malaise. Sindbis virus is widely and continuously found in insects and vertebrates in Eurasia, Africa, and Oceania. Clinical infection and disease in humans however has almost only been reported from Northern Europe (Finland, Sweden, Russian Karelia), where SINV is endemic and where large outbreaks occur intermittently. Cases are occasionally reported in Australia, China, and South Africa. SINV is an arbovirus, it is arthro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semliki Forest Virus
The Semliki Forest virus is an alphavirus found in central, eastern, and southern Africa. It was first isolated from mosquitoes in the Semliki Forest, Uganda by the Uganda Virus Research Institute in 1942 and described by Smithburn and Haddow. It is known to cause disease in animals including humans. The Semliki Forest virus is a positive-strand RNA virus with a genome of approximately 13,000 base pairs which encodes nine proteins. The 5’ two thirds of the genome encode four non-structural proteins concerned with RNA synthesis; the structural proteins are encoded in the 3’ one third. Of the structural proteins, the C proteins make up the icosahedral capsid, which is enveloped by a lipid bilayer derived from the host cell. The outermost surface of the virus is almost entirely covered by heterodimers of glycoproteins E1 and E2, arranged in interconnective trimers, which form an outer shell. Trimers are anchored in the membrane by an E2 cytoplasmic domain that associates with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alphaviruses
''Alphavirus'' is a genus of RNA viruses, the sole genus in the ''Togaviridae'' family. Alphaviruses belong to group IV of the Baltimore classification of viruses, with a positive-sense, single-stranded RNA genome. There are 32 alphaviruses, which infect various vertebrates such as humans, rodents, fish, birds, and larger mammals such as horses, as well as invertebrates. Alphaviruses that could infect both vertebrates and arthropods are referred dual-host alphaviruses, while insect-specific alphaviruses such as Eilat virus and Yada yada virus are restricted to their competent arthropod vector. Transmission between species and individuals occurs mainly via mosquitoes, making the alphaviruses a member of the collection of arboviruses – or arthropod-borne viruses. Alphavirus particles are enveloped, have a 70 nm diameter, tend to be spherical (although slightly pleomorphic), and have a 40 nm isometric nucleocapsid. Genome The alphaviruses are small, spherical, enve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
