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Streptococcal Pyrogenic Exotoxin
Streptococcal pyrogenic exotoxins also known as erythrogenic toxins, are exotoxins secreted by strains of the bacterial species ''Streptococcus pyogenes''. SpeA and speC are superantigens, which induce inflammation by nonspecifically activating T cells and stimulating the production of inflammatory cytokines. SpeB, the most abundant streptococcal extracellular protein, is a cysteine protease. Pyrogenic exotoxins are implicated as the causative agent of scarlet fever and streptococcal toxic shock syndrome. There is no consensus on the exact number of pyrogenic exotoxins. Serotypes A, B, and C are the most extensively studied and recognized by all sources, but others note up to thirteen distinct types, categorizing speF through speM as additional superantigens. Erythrogenic toxins are known to damage the plasma membranes of blood capillaries under the skin and produce a red skin rash (characteristic of scarlet fever). Past studies have shown that multiple variants of erythrogenic toxin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDB 1fnv EBI
PDB or pdb may refer to: Organizations * Party of German-speaking Belgians (German: '), a former Belgian political party * Promised Day Brigade, a former Iraqi organization Science and technology * Protein Data Bank, a biological molecule database ** Protein Data Bank (file format) * Potato dextrose broth, a microbiological growth medium * Pee Dee Belemnite, a reference standard for isotopes; see ''δ''13C Computing * PDB (Palm OS), a record database format * Pluggable database, in Oracle Database * Program database, a debugging information format * Python Debugger (pdb), of the Python programming language; see Stepping Other uses * Chess Problem Database Server (PDB Server), a repository for chess problems * Pousette-Dart Band, an American band * President's Daily Brief, a US intelligence document See also * 1,4-Dichlorobenzene or ''para''-dichlorobenzene (PDCB), a chemical * Bangladesh Power Development Board The Bangladesh Power Development Board (BPDB) is a governme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integrin
Integrins are transmembrane receptors that help cell–cell and cell–extracellular matrix (ECM) adhesion. Upon ligand binding, integrins activate signal transduction pathways that mediate cellular signals such as regulation of the cell cycle, organization of the intracellular cytoskeleton, and movement of new receptors to the cell membrane. The presence of integrins allows rapid and flexible responses to events at the cell surface (''e.g''. signal platelets to initiate an interaction with coagulation factors). Several types of integrins exist, and one cell generally has multiple different types on its surface. Integrins are found in all animals while integrin-like receptors are found in plant cells. Integrins work alongside other proteins such as cadherins, the immunoglobulin superfamily cell adhesion molecules, selectins and syndecans, to mediate cell–cell and cell–matrix interaction. Ligands for integrins include fibronectin, vitronectin, collagen and laminin. Stru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacterial Toxins
Microbial toxins are toxins produced by micro-organisms, including bacteria, fungi, protozoa, dinoflagellates, and viruses. Many microbial toxins promote infection and disease by directly damaging host tissues and by disabling the immune system. Endotoxins most commonly refer to the lipopolysaccharide (LPS) or lipooligosaccharide (LOS) that are in the outer plasma membrane of Gram-negative bacteria. The botulinum toxin, which is primarily produced by ''Clostridium botulinum'' and less frequently by other ''Clostridium'' species, is the most toxic substance known in the world. However, microbial toxins also have important uses in medical science and research. Currently, new methods of detecting bacterial toxins are being developed to better isolate and understand these toxins. Potential applications of toxin research include combating microbial virulence, the development of novel anticancer drugs and other medicines, and the use of toxins as tools in neurobiology and cellular biolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apoptosis
Apoptosis (from ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemistry, Biochemical events lead to characteristic cell changes (Morphology (biology), morphology) and death. These changes include Bleb (cell biology), blebbing, Plasmolysis, cell shrinkage, Karyorrhexis, nuclear fragmentation, Pyknosis, chromatin condensation, Apoptotic DNA fragmentation, DNA fragmentation, and mRNA decay. The average adult human loses 50 to 70 1,000,000,000, billion cells each day due to apoptosis. For the average human child between 8 and 14 years old, each day the approximate loss is 20 to 30 billion cells. In contrast to necrosis, which is a form of traumatic cell death that results from acute cellular injury, apoptosis is a highly regulated and controlled process that confers advantages during an organism's life cycle. For example, the separation of fingers and toes in a developing human embryo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complement System
The complement system, also known as complement cascade, is a part of the humoral, innate immune system and enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane. Despite being part of the innate immune system, the complement system can be recruited and brought into action by antibodies generated by the adaptive immune system. The complement system consists of a number of small, inactive, liver synthesized protein precursors circulating in the blood. When stimulated by one of several triggers, proteases in the system cleave specific proteins to release cytokines and initiate an amplifying cascade of further cleavages. The end result of this ''complement activation'' or ''complement fixation'' cascade is stimulation of phagocytes to clear foreign and damaged material, inflammation to attract additional phagocytes, and activation of the cell-killi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T-cell Receptor
The T-cell receptor (TCR) is a protein complex, located on the surface of T cells (also called T lymphocytes). They are responsible for recognizing fragments of antigen as peptides bound to major histocompatibility complex (MHC) molecules. The binding between TCR and antigen peptides is of relatively low affinity and is biologically degenerate (that is, many TCRs recognize the same antigen peptide, and many antigen peptides are recognized by the same TCR). The TCR is composed of two different protein chains (that is, it is a hetero dimer). In humans, in 95% of T cells the TCR consists of an alpha (α) chain and a beta (β) chain (encoded by '' TRA'' and ''TRB'', respectively), whereas in 5% of T cells the TCR consists of gamma and delta (γ/δ) chains (encoded by '' TRG'' and '' TRD'', respectively). This ratio changes during ontogeny and in diseased states (such as leukemia). It also differs between species. Orthologues of the 4 loci have been mapped in various speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MHC Class II
MHC Class II molecules are a class of major histocompatibility complex (MHC) molecules normally found only on professional antigen-presenting cells such as dendritic cells, macrophages, some endothelial cells, thymic epithelial cells, and B cells. These cells are important in initiating immune responses. Antigens presented by MHC class II molecules are exogenous, originating from extracellular proteins rather than cytosolic and endogenous sources like those presented by MHC class I. The loading of a MHC class II molecule occurs by phagocytosis. Extracellular proteins are endocytosed into a phagosome, which subsequently fuses with a lysosome to create a phagolysosome. Within the phagolysosome, lysosomal enzymes degrade the proteins into peptide fragments. These fragments are then loaded into the peptide-binding groove of the MHC class II molecule. Once loaded, the MHC class II-peptide complexes are transported to the plasma membrane via vesicular transport, where they prese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2215 Alpha-Beta T Cell Receptor
Fifteen or 15 may refer to: *15 (number) *one of the years 15 BC, AD 15, 1915, 2015 Music *Fifteen (band), a punk rock band Albums * ''15'' (Buckcherry album), 2005 * ''15'' (Ani Lorak album), 2007 * ''15'' (Phatfish album), 2008 * ''15'' (Tuki album), 2025 * ''15'' (mixtape), a 2018 mixtape by Bhad Bhabie * ''Fifteen'' (Green River Ordinance album), 2016 * ''Fifteen'' (The Wailin' Jennys album), 2017 * ''Fifteen'', a 2012 album by Colin James Songs * "Fifteen" (song), a 2008 song by Taylor Swift *"Fifteen", a song by Harry Belafonte from the album ''Love Is a Gentle Thing'' *"15", a song by Rilo Kiley from the album ''Under the Blacklight'' *"15", a song by Marilyn Manson from the album ''The High End of Low'' Other media * ''15'' (film), a 2003 Singaporean film * ''Fifteen'' (TV series), international release name of ''Hillside'', a Canadian-American teen drama * "Fifteen" (''Runaways''), an episode of ''Runaways'' *Fifteen (novel), a 1956 juvenile fiction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T-cell Dependent B-cell Act
T cells (also known as T lymphocytes) are an important part of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell surface. T cells are born from hematopoietic stem cells, found in the bone marrow. Developing T cells then migrate to the thymus gland to develop (or mature). T cells derive their name from the thymus. After migration to the thymus, the precursor cells mature into several distinct types of T cells. T cell differentiation also continues after they have left the thymus. Groups of specific, differentiated T cell subtypes have a variety of important functions in controlling and shaping the immune response. One of these functions is immune-mediated cell death, and it is carried out by two major subtypes: CD8+ "killer" (cytotoxic) and CD4+ "helper" T cells. (These are named for the presence of the cell surface proteins CD8 or CD4.) CD8+ T ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autocatalysis
In chemistry, a chemical reaction is said to be autocatalytic if one of the reaction products is also a catalyst for the same reaction. Many forms of autocatalysis are recognized.Steinfeld J.I., Francisco J.S. and Hase W.L. ''Chemical Kinetics and Dynamics'' (2nd ed., Prentice-Hall 1999) pp. 151–2 A ''set'' of chemical reactions can be said to be "collectively autocatalytic" if a number of those reactions produce, as reaction products, catalysts for enough of the other reactions that the entire set of chemical reactions is self-sustaining given an input of energy and food molecules (see autocatalytic set). Examples Acid-catalyzed hydrolysis of esters produces carboxylic acids that also catalyze the same reaction. Indeed, the observation of an accelerating hydrolysis of gamma valerolactone to gamma-hydroxyvaleric acid led to the introduction of the concept of autocatalysis in 1890. The oxidation of hydrocarbons by air or oxygen is the basis of autoxidation. Like many radic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zymogen
In biochemistry, a zymogen (), also called a proenzyme (), is an inactive precursor of an enzyme. A zymogen requires a biochemical change (such as a hydrolysis reaction revealing the active site, or changing the configuration to reveal the active site) to become an active enzyme. The biochemical change usually occurs in Golgi bodies, where a specific part of the precursor enzyme is cleaved in order to activate it. The inactivating piece which is cleaved off can be a peptide unit, or can be independently-folding domains comprising more than 100 residues. Although they limit the enzyme's ability, these N-terminal extensions of the enzyme or a "prosegment" often aid in the stabilization and folding of the enzyme they inhibit. The pancreas secretes zymogens partly to prevent the enzymes from digesting proteins in the cells where they are synthesised. Enzymes like pepsin are created in the form of pepsinogen, an inactive zymogen. Pepsinogen is activated when chief cells release ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDB 1b1z EBI
PDB or pdb may refer to: Organizations * Party of German-speaking Belgians (German: '), a former Belgian political party * Promised Day Brigade, a former Iraqi organization Science and technology * Protein Data Bank, a biological molecule database ** Protein Data Bank (file format) * Potato dextrose broth, a microbiological growth medium * Pee Dee Belemnite, a reference standard for isotopes; see ''δ''13C Computing * PDB (Palm OS), a record database format * Pluggable database, in Oracle Database * Program database, a debugging information format * Python Debugger (pdb), of the Python programming language; see Stepping Other uses * Chess Problem Database Server (PDB Server), a repository for chess problems * Pousette-Dart Band, an American band * President's Daily Brief, a US intelligence document See also * 1,4-Dichlorobenzene or ''para''-dichlorobenzene (PDCB), a chemical * Bangladesh Power Development Board The Bangladesh Power Development Board (BPDB) is a governme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
