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VapBC
VapBC (virulence associated proteins B and C) is the largest family of type II toxin-antitoxin system genetic loci in prokaryotes. VapBC operons consist of two genes: ''VapC'' encodes a toxic PilT N-terminus (PIN) domain, and ''VapB'' encodes a matching antitoxin. The toxins in this family are thought to perform RNA cleavage, which is inhibited by the co-expression of the antitoxin, in a manner analogous to a poison and antidote. First discovered in 1992, vapBC loci are now thought make up around 37–42% of all type II toxin-antitoxin systems. Discovery Following the discoveries of two other type II toxin-antitoxin systems, the first vapBC system to be characterised was found in '' Salmonella dublin'' strain G19 in 1992. It was characterised as a system for ensuring that all daughter cells contained a copy of the plasmid encoding the vapBC locus. The two components of this plasmidic system were originally named ''vagC'' and ''vagD'' (virulence-associated gene) for the toxin and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxin-antitoxin System
A toxin-antitoxin system is a set of two or more closely linked genes that together encode both a "toxin" protein and a corresponding "antitoxin". Toxin-antitoxin systems are widely distributed in prokaryotes, and organisms often have them in multiple copies. When these systems are contained on plasmids – transferable genetic elements – they ensure that only the daughter cells that inherit the plasmid survive after cell division. If the plasmid is absent in a daughter cell, the unstable antitoxin is degraded and the stable toxic protein kills the new cell; this is known as 'post-segregational killing' (PSK). Toxin-antitoxin systems are typically classified according to how the antitoxin neutralises the toxin. In a type I toxin-antitoxin system, the translation of messenger RNA (mRNA) that encodes the toxin is inhibited by the binding of a small non-coding RNA antitoxin that binds the toxin mRNA. The toxic protein in a type II system is inhibited post-translationally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDB 1o4w EBI
PDB may refer to: * Chess Problem Database Server (PDB Server) * 1,4-Dichlorobenzene (paradichlorobenzene) * Party of German-speaking Belgians, (German: '), a political party and predecessor of the ProDG * PDB (Palm OS), a container format for record databases in Palm OS, Garnet OS and Access Linux Platform * ''Pee Dee Belemnite'', a standard for stable Carbon-13 and Oxygen-18 isotopes; see * Pluggable database, such as an Oracle Database in a multitenancy environment * Potato dextrose broth, a common microbiological growth media * Pousette-Dart Band * President's Daily Brief or Briefing or Bulletin, a top-secret intelligence document produced each morning for the U.S. President * Program database, a file format for storing debugging information * Promised Day Brigade, an Iraqi Shia organisation * Protein Data Bank * Protein Data Bank (file format) * Python Debugger, see Python (programming language) Python is a high-level, general-purpose programming language. Its design philos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxin-antitoxin Database
TADB is a database of Type 2 toxin-antitoxin loci in bacterial and archaeal genomes. See also *Toxin-antitoxin system A toxin-antitoxin system is a set of two or more closely linked genes that together encode both a "toxin" protein and a corresponding "antitoxin". Toxin-antitoxin systems are widely distributed in prokaryotes, and organisms often have them in mult ... References External links TADB Biological databases Plasmids Non-coding RNA Toxins RNA-binding proteins {{Biodatabase-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Shock
The heat shock response (HSR) is a cell stress response that increases the number of molecular chaperones to combat the negative effects on proteins caused by stressors such as increased temperatures, oxidative stress, and heavy metals. In a normal cell, proteostasis (protein homeostasis) must be maintained because proteins are the main functional units of the cell. Many proteins take on a defined configuration in a process known as protein folding in order to perform their biological functions. If these structures are altered, critical processes could be affected, leading to cell damage or death. The heat shock response can be employed under stress to induce the expression of heat shock proteins (HSP), many of which are molecular chaperones, that help prevent or reverse protein misfolding and provide an environment for proper folding. Protein folding is already challenging due to the crowded intracellular space where aberrant interactions can arise; it becomes more difficult when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfolobus
''Sulfolobus'' is a genus of microorganism in the family Sulfolobaceae. It belongs to the archaea domain. ''Sulfolobus'' species grow in volcanic springs with optimal growth occurring at pH 2-3 and temperatures of 75-80 °C, making them acidophiles and thermophiles respectively. ''Sulfolobus'' cells are irregularly shaped and flagellar. Species of ''Sulfolobus'' are generally named after the location from which they were first isolated, e.g. ''Sulfolobus solfataricus'' was first isolated in the Solfatara volcano. Other species can be found throughout the world in areas of volcanic or geothermal activity, such as geological formations called mud pots, which are also known as ''solfatare'' (plural of solfatara). ''Sulfolobus'' as a model to study the molecular mechanisms of DNA replication When the first Archaeal genome, '' Methanococcus jannaschii'', had been sequenced completely in 1996, it was found that the genes in the genome of ''Methanococcus jannaschii'' involv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperthermophile
A hyperthermophile is an organism that thrives in extremely hot environments—from 60 °C (140 °F) upwards. An optimal temperature for the existence of hyperthermophiles is often above 80 °C (176 °F). Hyperthermophiles are often within the domain Archaea, although some bacteria are also able to tolerate extreme temperatures. Some of these bacteria are able to live at temperatures greater than 100 °C, deep in the ocean where high pressures increase the boiling point of water. Many hyperthermophiles are also able to withstand other environmental extremes, such as high acidity or high radiation levels. Hyperthermophiles are a subset of extremophiles. Their existence may support the possibility of extraterrestrial life, showing that life can thrive in environmental extremes. History Hyperthermophiles isolated from hot springs in Yellowstone National Park were first reported by Thomas D. Brock in 1965. Since then, more than 70 species have been established. The most extreme hypert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRNA
Transfer RNA (abbreviated tRNA and formerly referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes), that serves as the physical link between the mRNA and the amino acid sequence of proteins. tRNAs genes from Bacteria are typically shorter (mean = 77.6 bp) than tRNAs from Archaea (mean = 83.1 bp) and eukaryotes (mean = 84.7 bp). The mature tRNA follows an opposite pattern with tRNAs from Bacteria being usually longer (median = 77.6 nt) than tRNAs from Archaea (median = 76.8 nt), with eukaryotes exhibiting the shortest mature tRNAs (median = 74.5 nt). Transfer RNA (tRNA) does this by carrying an amino acid to the protein synthesizing machinery of a cell called the ribosome. Complementation of a 3-nucleotide codon in a messenger RNA (mRNA) by a 3-nucleotide anticodon of the tRNA results in protein synthesis based on the mRNA code. As such, tRNAs are a necessary component of translation, the biological ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salmonella Enterica
''Salmonella enterica'' (formerly ''Salmonella choleraesuis'') is a rod-headed, flagellate, facultative anaerobic, Gram-negative bacterium and a species of the genus ''Salmonella''. A number of its serovars are serious human pathogens. Epidemiology Most cases of salmonellosis are caused by food infected with ''S. enterica'', which often infects cattle and poultry, though other animals such as domestic cats and hamsters have also been shown to be sources of infection in humans. Investigations of vacuum cleaner bags have shown that households can act as a reservoir of the bacterium; this is more likely if the household has contact with an infection source (i.e., members working with cattle or in a veterinary clinic). Raw chicken eggs and goose eggs can harbor ''S. enterica'', initially in the egg whites, although most eggs are not infected. As the egg ages at room temperature, the yolk membrane begins to break down and ''S. enterica'' can spread into the yolk. Refrigeration a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shigella Flexneri
''Shigella flexneri'' is a species of Gram-negative bacteria in the genus ''Shigella'' that can cause diarrhea in humans. Several different serogroups of ''Shigella'' are described; ''S. flexneri'' belongs to group ''B''. ''S. flexneri'' infections can usually be treated with antibiotics, although some strains have become resistant. Less severe cases are not usually treated because they become more resistant in the future. Shigella are closely related to ''Escherichia coli'', but can be differentiated from ''E.coli'' based on pathogenicity, physiology (failure to ferment lactose or decarboxylate lysine) and serology. Discovery The species was named after the American physician Simon Flexner; the genus Shigella is named after Japanese physician Kiyoshi Shiga, who researched the cause of dysentery. Shiga entered the Tokyo Imperial University School of Medicine in 1892, during which he attended a lecture by Dr. Shibasaburo Kitasato. Shiga was impressed by Dr. Kitasato's intellect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribonuclease
Ribonuclease (commonly abbreviated RNase) is a type of nuclease that catalyzes the degradation of RNA into smaller components. Ribonucleases can be divided into endoribonucleases and exoribonucleases, and comprise several sub-classes within the EC 2.7 (for the phosphorolytic enzymes) and 3.1 (for the hydrolytic enzymes) classes of enzymes. Function All organisms studied contain many RNases of two different classes, showing that RNA degradation is a very ancient and important process. As well as clearing of cellular RNA that is no longer required, RNases play key roles in the maturation of all RNA molecules, both messenger RNAs that carry genetic material for making proteins and non-coding RNAs that function in varied cellular processes. In addition, active RNA degradation systems are the first defense against RNA viruses and provide the underlying machinery for more advanced cellular immune strategies such as RNAi. Some cells also secrete copious quantities of non-specific RN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinorhizobium Meliloti
''Ensifer meliloti'' (formerly ''Rhizobium meliloti'' and ''Sinorhizobium meliloti'') are an aerobic, Gram-negative, and diazotrophic species of bacteria. ''S. meliloti'' are motile and possess a cluster of peritrichous flagella. ''S. meliloti'' fix atmospheric nitrogen into ammonia for their legume symbionts, such as alfalfa. ''S. meliloti'' forms a symbiotic relationship with legumes from the genera ''Medicago'', ''Melilotus'' and ''Trigonella'', including the model legume ''Medicago truncatula''. This symbiosis promotes the development of a plant organ, termed a root nodule. Because soil often contains a limited amount of nitrogen for plant use, the symbiotic relationship between ''S. meliloti'' and their legume hosts has agricultural applications. These techniques reduce the need for inorganic nitrogenous fertilizers. Symbiosis Symbiosis between ''S. meliloti'' and its legume hosts begins when the plant secretes an array of betaines and flavonoids into the rhizosphere: 4,4†... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
