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Measles Virus
''Measles morbillivirus'' (MeV), also called measles virus (MV), is a single-stranded, negative-sense, enveloped, non-segmented RNA virus of the genus '' Morbillivirus'' within the family '' Paramyxoviridae''. It is the cause of measles. Humans are the natural hosts of the virus; no animal reservoirs are known to exist. Disease The virus causes measles, a highly contagious disease transmitted by respiratory aerosols that triggers a temporary but severe immunosuppression. Symptoms include fever, cough, runny nose, inflamed eyes and a generalized, maculopapular, erythematous rash and a pathognomic Koplik spot seen on buccal mucosa opposite to lower 1 st and 2 nd molars . The virus is spread by coughing and sneezing via close personal contact or direct contact with secretions. Replication cycle Entry The measles virus has two envelope glycoproteins on the viral surface – hemagglutinin (H) and membrane fusion protein (F). These proteins are responsible for host ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Micrograph
A micrograph or photomicrograph is a photograph or digital image taken through a microscope or similar device to show a magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken on a microscope but is only slightly magnified, usually less than 10 times. Micrography is the practice or art of using microscopes to make photographs. A micrograph contains extensive details of microstructure. A wealth of information can be obtained from a simple micrograph like behavior of the material under different conditions, the phases found in the system, failure analysis, grain size estimation, elemental analysis and so on. Micrographs are widely used in all fields of microscopy. Types Photomicrograph A light micrograph or photomicrograph is a micrograph prepared using an optical microscope, a process referred to as ''photomicroscopy''. At a basic level, photomicroscopy may be performed simply by connecting a camera to a microscope, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemagglutinin
In molecular biology, hemagglutinins (or ''haemagglutinin'' in British English) (from the Greek , 'blood' + Latin , 'glue') are receptor-binding membrane fusion glycoproteins produced by viruses in the '' Paramyxoviridae'' family. Hemagglutinins are responsible for binding to receptors on red blood cells to initiate viral attachment and infection. The agglutination of red cells occurs when antibodies on one cell bind to those on others, causing amorphous aggregates of clumped cells.Hemagglutinins recognize cell-surface glycoconjugates containing sialic acid on the surface of host red blood cells with a low affinity, and use them to enter the endosome of host cells. In the endosome, hemagglutinins are activated at a pH of 5 - 6.5, to undergo conformational changes that enable viral attachment through a fusion peptide. Agglutination and hemagglutinins were discovered by virologist George K. Hirst in 1941. Alfred Gottschalk proved in 1957 that hemagglutinins bind a virus to a host ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Measles Virion
Measles is a highly contagious infectious disease caused by measles virus. Symptoms usually develop 10–12 days after exposure to an infected person and last 7–10 days. Initial symptoms typically include fever, often greater than , cough, runny nose, and inflamed eyes. Small white spots known as Koplik's spots may form inside the mouth two or three days after the start of symptoms. A red, flat rash which usually starts on the face and then spreads to the rest of the body typically begins three to five days after the start of symptoms. Common complications include diarrhea (in 8% of cases), middle ear infection (7%), and pneumonia (6%). These occur in part due to measles-induced immunosuppression. Less commonly seizures, blindness, or inflammation of the brain may occur. Other names include ''morbilli'', ''rubeola'', ''red measles'', and ''English measles''. Both rubella, also known as ''German measles'', and roseola are different diseases caused by unrelated viruses. Me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lysis
Lysis ( ) is the breaking down of the membrane of a cell, often by viral, enzymic, or osmotic (that is, "lytic" ) mechanisms that compromise its integrity. A fluid containing the contents of lysed cells is called a ''lysate''. In molecular biology, biochemistry, and cell biology laboratories, cell cultures may be subjected to lysis in the process of purifying their components, as in protein purification, DNA extraction, RNA extraction, or in purifying organelles. Many species of bacteria are subject to lysis by the enzyme lysozyme, found in animal saliva, egg white, and other secretions. Phage lytic enzymes (lysins) produced during bacteriophage infection are responsible for the ability of these viruses to lyse bacterial cells. Penicillin and related β-lactam antibiotics cause the death of bacteria through enzyme-mediated lysis that occurs after the drug causes the bacterium to form a defective cell wall. If the cell wall is completely lost and the penicillin was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribosome
Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to form polypeptide chains. Ribosomes consist of two major components: the small and large ribosomal subunits. Each subunit consists of one or more ribosomal RNA (rRNA) molecules and many ribosomal proteins (RPs or r-proteins). The ribosomes and associated molecules are also known as the ''translational apparatus''. Overview The sequence of DNA that encodes the sequence of the amino acids in a protein is transcribed into a messenger RNA chain. Ribosomes bind to messenger RNAs and use their sequences for determining the correct sequence of amino acids to generate a given protein. Amino acids are selected and carried to the ribosome by transfer RNA (tRNA) molecules, which enter the ribosome and bind to the messenger RNA chain via an anti-co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Translation (biology)
In molecular biology and genetics, translation is the process in which ribosomes in the cytoplasm or endoplasmic reticulum synthesize proteins after the process of transcription of DNA to RNA in the cell's nucleus. The entire process is called gene expression. In translation, messenger RNA (mRNA) is decoded in a ribosome, outside the nucleus, to produce a specific amino acid chain, or polypeptide. The polypeptide later folds into an active protein and performs its functions in the cell. The ribosome facilitates decoding by inducing the binding of complementary tRNA anticodon sequences to mRNA codons. The tRNAs carry specific amino acids that are chained together into a polypeptide as the mRNA passes through and is "read" by the ribosome. Translation proceeds in three phases: # Initiation: The ribosome assembles around the target mRNA. The first tRNA is attached at the start codon. # Elongation: The last tRNA validated by the small ribosomal subunit (''acc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898,Dimmock p. 4 more than 9,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, or ''virions'', consisting of (i) the genetic mate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNA-dependent RNA Polymerase
RNA-dependent RNA polymerase (RdRp) or RNA replicase is an enzyme that catalyzes the replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand complementary to a given RNA template. This is in contrast to typical DNA-dependent RNA polymerases, which all organisms use to catalyze the transcription of RNA from a DNA template. RdRp is an essential protein encoded in the genomes of most RNA-containing viruses with no DNA stage including SARS-CoV-2. Some eukaryotes also contain RdRps, which are involved in RNA interference and differ structurally from viral RdRps. History Viral RdRps were discovered in the early 1960s from studies on mengovirus and polio virus when it was observed that these viruses were not sensitive to actinomycin D, a drug that inhibits cellular DNA-directed RNA synthesis. This lack of sensitivity suggested that there is a virus-specific enzyme that could copy RNA from an RNA template and not from a DNA template. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sense (molecular Biology)
In molecular biology and genetics, the sense of a nucleic acid molecule, particularly of a strand of DNA or RNA, refers to the nature of the roles of the strand and its complement in specifying a sequence of amino acids. Depending on the context, sense may have slightly different meanings. For example, negative-sense strand of DNA is equivalent to the template strand, whereas the positive-sense strand is the non-template strand whose nucleotide sequence is equivalent to the sequence of the mRNA transcript. DNA sense Because of the complementary nature of base-pairing between nucleic acid polymers, a double-stranded DNA molecule will be composed of two strands with sequences that are reverse complements of each other. To help molecular biologists specifically identify each strand individually, the two strands are usually differentiated as the "sense" strand and the "antisense" strand. An individual strand of DNA is referred to as positive-sense (also positive (+) or simply sens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poliovirus Receptor-related 1
Poliovirus receptor-related 1 (PVRL1), also known as nectin-1 and CD111 (formerly herpesvirus entry mediator C, HVEC) is a human protein of the immunoglobulin superfamily (IgSF), also considered a member of the nectins. It is a membrane protein with three extracellular immunoglobulin domains, a single transmembrane helix and a cytoplasmic tail. The protein can mediate Ca2+-independent cellular adhesion further characterizing it as IgSF cell adhesion molecule (IgSF CAM). Function PVRL1 is an adhesion molecule found in a wide range of tissues where it localizes in various junctions such as the adherens junction of epithelial tissue or the chemical synapse of neurons. The cytoplasmic tail of PVRL1 can bind the protein afadin which is a scaffolding protein that binds actin. In the chemical synapse PVRL1 interacts with PVRL3 (nectin-3) and both proteins can be found in neuronal tissue already in early stages of brain development as well as in aging brains. The two proteins have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nectin
Nectins and Nectin-like molecules (Necl) are families of cellular adhesion molecules involved in Ca2+-independent cellular adhesion. Nectins are ubiquitously expressed and have adhesive roles in a wide range of tissues such as the adherens junction of epithelia or the chemical synapse of the neuronal tissue. Diversity So far four nectins have been identified in humans, namely nectin-1, nectin-2, nectin-3 and nectin-4. These four family members have also been found in most other well studied mammals. Also, five Necls have been identified, these are: Necl-1, Necl-2, Necl-3, Necl-4 and Necl-5. Structure All nectins and all Necls share the same overall structure defined by three extra cellular immunoglobulin domains, a single transmembrane helix and an intracellular domain. For all nectins the intracellular domain can bind a scaffold protein named afadin (the product of the MLLT4 gene). All nectins and Necls can form homo-cis dimers, meaning a dimer of two alike molecu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SLAMF1
Signaling lymphocytic activation molecule 1 is a protein that in humans is encoded by the ''SLAMF1'' gene. Recently SLAMF1 has also been designated CD150 (cluster of differentiation 150). SLAMF1 belongs to the signaling lymphocytic activation molecule family. The interaction of SLAMF1 promoter and enhancers with the Early B-cell factor 1 (EBF1) is required for the expression of SLAMF1 gene in B cells. STAT6, IRF4, and NF-kB factors involved in the transfer of the signals from the B-cell receptor, its co-receptors and IL-4R, also play important role in the regulation of SLAMF1 expression. Interactions SLAMF1 has been shown to interact with PTPN11, SH2D1A SH2 domain–containing protein 1A is a protein that in humans is encoded by the ''SH2D1A'' gene. It is often called SLAM-associated protein (symbol SAP), where "SLAM" refers to signaling lymphocytic activation molecules. It is a SH2 domain–co ... and SH2D1B. References Further reading * * * * * * * * * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
