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Viral Entry
Viral entry is the earliest stage of infection in the viral life cycle, as the virus comes into contact with the host cell (biology), cell and introduces viral material into the cell. The major steps involved in viral entry are shown below. Despite the variation among viruses, there are several shared generalities concerning viral entry. Reducing cellular proximity How a virus enters a cell is different depending on the type of virus it is. A virus with a Viral envelope, nonenveloped capsid enters the cell by attaching to the attachment factor located on a host cell. It then enters the cell by endocytosis or by making a hole in the membrane of the host cell and inserting its viral genome. Cell entry by enveloped viruses is more complicated. Enveloped viruses enter the cell by attaching to an attachment factor located on the surface of the host cell. They then enter by endocytosis or a direct membrane fusion event. The fusion event is when the virus membrane and the host cell m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viral Life Cycle
Viruses are only able to Replicate (biology), replicate themselves by commandeering the reproductive apparatus of cells and making them reproduce the virus's genetic structure and virion, particles instead. How viruses do this depends mainly on the type of nucleic acid DNA or RNA they contain, which is either one or the other but never both. Viruses cannot function or reproduce outside a cell, and are totally dependent on a host cell (biology), cell to survive. Most viruses are species specific, and related viruses typically only infect a narrow range of plants, animals, bacteria, or fungi.N.J. Dimmock et al. ''Introduction to Modern Virology'', 6th edition. Blackwell Publishing, 2007. Life cycle process Viral entry For the virus to reproduce and thereby establish infection, it must enter cells of the host organism and use those cells' materials. To enter the cells, proteins on the surface of the virus interact with proteins of the cell. Attachment, or adsorption, occurs between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytoplasm
The cytoplasm describes all the material within a eukaryotic or prokaryotic cell, enclosed by the cell membrane, including the organelles and excluding the nucleus in eukaryotic cells. The material inside the nucleus of a eukaryotic cell and contained within the nuclear membrane is termed the nucleoplasm. The main components of the cytoplasm are the cytosol (a gel-like substance), the cell's internal sub-structures, and various cytoplasmic inclusions. In eukaryotes the cytoplasm also includes the nucleus, and other membrane-bound organelles.The cytoplasm is about 80% water and is usually colorless. The submicroscopic ground cell substance, or cytoplasmic matrix, that remains after the exclusion of the cell organelles and particles is groundplasm. It is the hyaloplasm of light microscopy, a highly complex, polyphasic system in which all resolvable cytoplasmic elements are suspended, including the larger organelles such as the ribosomes, mitochondria, plant plasti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteriophage
A bacteriophage (), also known informally as a phage (), is a virus that infects and replicates within bacteria. The term is derived . Bacteriophages are composed of proteins that Capsid, encapsulate a DNA or RNA genome, and may have structures that are either simple or elaborate. Their genomes may encode as few as four genes (e.g. Bacteriophage MS2, MS2) and as many as hundreds of genes. Phages replicate within the bacterium following the injection of their genome into its cytoplasm. Bacteriophages are among the most common and diverse entities in the biosphere. Bacteriophages are ubiquitous viruses, found wherever bacteria exist. It is estimated there are more than 1031 bacteriophages on the planet, more than every other organism on Earth, including bacteria, combined. Viruses are the most abundant biological entity in the water column of the world's oceans, and the second largest component of biomass after prokaryotes, where up to 9x108 virus, virions per millilitre have b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Positive-strand RNA Virus
Positive-strand RNA viruses (+ssRNA viruses) are a group of related viruses that have Sense (molecular biology), positive-sense, single-stranded genomes made of ribonucleic acid. The positive-sense genome can act as messenger RNA (mRNA) and can be directly translation (biology), translated into viral proteins by the host cell, host cell's ribosomes. Positive-strand RNA viruses encode an RNA-dependent RNA polymerase (RdRp) which is used during replication of the genome to synthesize a negative-sense antigenome that is then used as a template to create a new positive-sense viral genome. Positive-strand RNA viruses are divided between the phyla ''Kitrinoviricota'', ''Lenarviricota'', and ''Pisuviricota'' (specifically classes ''Pisoniviricetes'' and ''Stelpaviricetes, Stelpavirictes'') all of which are in the kingdom ''Orthornavirae'' and Realm (virology), realm ''Riboviria''. They are Monophyly, monophyletic and descended from a common RNA virus ancestor. In the Baltimore classi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SARS-CoV-2
Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) is a strain of coronavirus that causes COVID-19, the respiratory illness responsible for the COVID-19 pandemic. The virus previously had the Novel coronavirus, provisional name 2019 novel coronavirus (2019-nCoV), and has also been called human coronavirus 2019 (HCoV-19 or hCoV-19). First identified in the city of Wuhan, Hubei, China, the World Health Organization designated the outbreak a public health emergency of international concern from January 30, 2020, to May 5, 2023. SARS‑CoV‑2 is a positive-sense single-stranded RNA virus that is Contagious disease, contagious in humans. SARS‑CoV‑2 is a strain of the species ''Betacoronavirus pandemicum'' (SARSr-CoV), as is SARS-CoV-1, the virus that caused the 2002–2004 SARS outbreak. There are animal-borne coronavirus strains more closely related to SARS-CoV-2, the most closely known relative being the BANAL-52 bat coronavirus. SARS-CoV-2 is of Zoonosis, z ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foot-and-mouth Disease Virus
Foot-and-mouth disease virus (FMDV) is a virus in the genus '' Aphthovirus'' that causes foot-and-mouth disease. As a member of the family ''Picornaviridae'', FMDV is a positive-sense, single-stranded RNA virus. Like other members of the picornavirus family, FMDV is small and unenveloped, with an icosahedral capsid. The virus causes foot-and-mouth disease, a highly contagious disease affecting cattle, pigs, sheep, goats, and other cloven-hoofed animals. Foot-and-mouth disease causes fever and the formation of vesicles (blisters) in infected animals, which form in the mouth and on the feet and teats. While the disease is usually nonfatal to adult livestock, survivors are left in a weakened state which impacts both meat and milk production, making outbreaks very costly and disruptive to agricultural production overall. Structure and genome The virus particle (25-30 nm) has an icosahedral capsid made of protein, without envelope, containing a positive-sense (mRNA sens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hepatitis C Virus
The hepatitis C virus (HCV) is a small (55–65 nm in size), enveloped, positive-sense single-stranded RNA virus of the family ''Flaviviridae''. The hepatitis C virus is the cause of hepatitis C and some cancers such as liver cancer ( hepatocellular carcinoma, abbreviated HCC) and lymphomas in humans. Taxonomy The hepatitis C virus belongs to the genus '' Hepacivirus'', a member of the family ''Flaviviridae''. Before 2011, it was considered to be the only member of this genus. However a member of this genus has been discovered in dogs: canine hepacivirus. There is also at least one virus in this genus that infects horses. Several additional viruses in the genus have been described in bats and rodents. Structure The hepatitis C virus particle consists of a lipid membrane envelope that is 55 to 65 nm in diameter. Two viral envelope glycoproteins, E1 and E2, are embedded in the lipid envelope. They take part in viral attachment and entry into the cell. Within the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poliovirus
Poliovirus, the causative agent of polio (also known as poliomyelitis), is a serotype of the species '' Enterovirus C'', in the family of '' Picornaviridae''. There are three poliovirus serotypes, numbered 1, 2, and 3. Poliovirus is composed of an RNA genome and a protein capsid. The genome is a single-stranded positive-sense RNA (+ssRNA) genome that is about 7500 nucleotides long. The viral particle is about 30 nm in diameter with icosahedral symmetry. Because of its short genome and its simple composition—only a strand of RNA and a nonenveloped icosahedral protein coat encapsulating it—poliovirus is widely regarded as the simplest significant virus. Poliovirus is one of the most well-characterized viruses, and has become a useful model system for understanding the biology of RNA viruses. Replication cycle Poliovirus infects human cells by binding to an immunoglobulin-like receptor, CD155 (also known as the poliovirus receptor or PVR) on the cell surface. Inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vesicle (biology And Chemistry)
In cell biology, a vesicle is a structure within or outside a cell, consisting of liquid or cytoplasm enclosed by a lipid bilayer. Vesicles form naturally during the processes of secretion ( exocytosis), uptake (endocytosis), and the transport of materials within the plasma membrane. Alternatively, they may be prepared artificially, in which case they are called liposomes (not to be confused with lysosomes). If there is only one phospholipid bilayer, the vesicles are called ''unilamellar liposomes''; otherwise they are called ''multilamellar liposomes''. The membrane enclosing the vesicle is also a lamellar phase, similar to that of the plasma membrane, and intracellular vesicles can fuse with the plasma membrane to release their contents outside the cell. Vesicles can also fuse with other organelles within the cell. A vesicle released from the cell is known as an extracellular vesicle. Vesicles perform a variety of functions. Because it is separated from the cytosol, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viral Entry (Endocytosis And Lysis)
The word ''Viral'' means "relating to viruses" (small infectious agents). It may also refer to: Viral behavior, or virality Memetic behavior likened that of a virus, for example: * Viral marketing, the use of existing social networks to spread a marketing message * Viral phenomenon, relating to contagion theory or the "virality" of network culture, such as a meme * Viral video Viral videos are video, videos that become popular through viral phenomenon, a viral process of Internet sharing, primarily through video sharing websites such as YouTube as well as social media and email.Lu Jiang, Yajie Miao, Yi Yang, ZhenZhon ..., a video that quickly attains a high popularity Titled works * ''Viral'' (2016 American film), a 2016 American science fiction horror drama * ''Viral'' (2016 Hindi film), an Indian Bollywood film based on social media * ''Viral'' (upcoming film), an American psychological thriller film starring Blair Underwood * ''Viral'' (web series), a 2014 B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angiotensin-converting Enzyme 2
Angiotensin-converting enzyme 2 (ACE2) is an enzyme that can be found either attached to the membrane of cells (mACE2) in the intestines, kidney, testis, gallbladder, and heart or in a soluble form (sACE2). Both membrane bound and soluble ACE2 are integral parts of the renin–angiotensin–aldosterone system (RAAS) that exists to keep the body's blood pressure in check. mACE2 is cleaved by the enzyme ADAM17 in a process regulated by substrate presentation. ADAM17 cleavage releases the extracellular domain creating soluble ACE2 (sACE2). ACE2 enzyme activity opposes the classical arm of the RAAS by lowering blood pressure through catalyzing the hydrolysis of angiotensin II (a vasoconstrictor peptide which raises blood pressure) into angiotensin (1–7) (a vasodilator). Angiotensin (1-7) in turns binds to MasR receptors creating localized vasodilation and hence decreasing blood pressure. This decrease in blood pressure makes the entire process a promising drug target for tre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coronavirus Spike Protein
Spike (S) glycoprotein (sometimes also called spike protein, formerly known as E2) is the largest of the four major structural proteins found in coronaviruses. The spike protein assembles into trimers that form large structures, called spikes or peplomers, that project from the surface of the virion. The distinctive appearance of these spikes when visualized using negative stain transmission electron microscopy, "recalling the solar corona", gives the virus family its main name. The function of the spike glycoprotein is to mediate viral entry into the host cell by first interacting with molecules on the exterior cell surface and then fusing the viral and cellular membranes. Spike glycoprotein is a class I fusion protein that contains two regions, known as S1 and S2, responsible for these two functions. The S1 region contains the receptor-binding domain that binds to receptors on the cell surface. Coronaviruses use a very diverse range of receptors; HCoV-NL63, SARS-CoV ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
