|
Zinc-dependent Phospholipase C
In molecular biology, zinc-dependent phospholipases C is a family of bacterial phospholipases C enzymes, some of which are also known as alpha toxins. ''Bacillus cereus'' contains a monomeric phospholipase C (PLC) of 245 amino-acid residues. Although PLC prefers to act on phosphatidylcholine, it also shows weak catalytic activity with sphingomyelin and phosphatidylinositol. Sequence studies have shown the protein to be similar both to alpha toxin from ''Clostridium perfringens'' and ''Clostridium bifermentans'', a phospholipase C involved in haemolysis and cell rupture, and to lecithinase from ''Listeria monocytogenes'', which aids cell-to-cell spread by breaking down the 2-membrane vacuoles that surround the bacterium during transfer. Each of these proteins is a zinc-dependent enzyme, binding 3 zinc ions per molecule. The enzymes catalyse the conversion of phosphatidylcholine and water to 1,2-diacylglycerol and choline phosphate. In ''Bacillus cereus'', there are nine residu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clostridium Perfringens Alpha Toxin
''Clostridium perfringens'' alpha toxin is a toxin produced by the bacterium ''Clostridium perfringens'' (''C. perfringens'') and is responsible for gas gangrene and myonecrosis in infected tissues. The toxin also possesses hemolytic activity. Clinical significance This toxin has been shown to be the key virulence factor in infection with ''C. perfringens''; the bacterium is unable to cause disease without this toxin. Further, vaccination against the alpha toxin toxoid protects mice against ''C. perfringens'' gas gangrene. As a result, knowledge about the function of this particular protein greatly aids understanding of myonecrosis. Structure and homology The alpha toxin has remarkable similarity to toxins produced by other bacteria as well as natural enzymes. There is significant homology with phospholipase C enzymes from ''Bacillus cereus'', ''C. bifermentans'', and ''Listeria monocytogenes''. The C terminal domain shows similarity with non-bacterial enzymes such as pancreati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clostridium Perfringens
''Clostridium perfringens'' (formerly known as ''C. welchii'', or ''Bacillus welchii'') is a Gram-positive, rod-shaped, anaerobic, spore-forming pathogenic bacterium of the genus '' Clostridium''. ''C. perfringens'' is ever-present in nature and can be found as a normal component of decaying vegetation, marine sediment, the intestinal tract of humans and other vertebrates, insects, and soil. It has the shortest reported generation time of any organism at 6.3 minutes in thioglycolate medium. ''Clostridium perfringens'' is one of the most common causes of food poisoning in the United States, alongside norovirus, ''Salmonella'', '' Campylobacter'', and ''Staphylococcus aureus''. However, it can sometimes be ingested and cause no harm. Infections due to ''C. perfringens'' show evidence of tissue necrosis, bacteremia, emphysematous cholecystitis, and gas gangrene, also known as clostridial myonecrosis. The specific name ''perfringens'' is derived from the Latin ''per'' (meaning " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Domains
In molecular biology, a protein domain is a region of a protein's polypeptide chain that is self-stabilizing and that folds independently from the rest. Each domain forms a compact folded three-dimensional structure. Many proteins consist of several domains, and a domain may appear in a variety of different proteins. Molecular evolution uses domains as building blocks and these may be recombined in different arrangements to create proteins with different functions. In general, domains vary in length from between about 50 amino acids up to 250 amino acids in length. The shortest domains, such as zinc fingers, are stabilized by metal ions or disulfide bridges. Domains often form functional units, such as the calcium-binding EF hand domain of calmodulin. Because they are independently stable, domains can be "swapped" by genetic engineering between one protein and another to make chimeric proteins. Background The concept of the domain was first proposed in 1973 by Wetlaufer after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PLAT Domain
In the United States, a plat ( or ) (plan) is a cadastral map, drawn to scale, showing the divisions of a piece of land. United States General Land Office surveyors drafted township plats of Public Lands Surveys to show the distance and bearing between section corners, sometimes including topographic or vegetation information. City, town or village plats show subdivisions broken into blocks with streets and alleys. Further refinement often splits blocks into individual lots, usually for the purpose of selling the described lots; this has become known as subdivision. After the filing of a plat, legal descriptions can refer to block and lot-numbers rather than portions of sections. In order for plats to become legally valid, a local governing body, such as a public works department, urban planning commission, or zoning board must normally review and approve them. In gardening history, in both varieties of English (and in French etc), a "plat" means a section of a formal parte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Listeria Monocytogenes
''Listeria monocytogenes'' is the species of pathogenic bacteria that causes the infection listeriosis. It is a facultative anaerobic bacterium, capable of surviving in the presence or absence of oxygen. It can grow and reproduce inside the host's cells and is one of the most virulent foodborne pathogens: 20 to 30% of foodborne listeriosis infections in high-risk individuals may be fatal. Responsible for an estimated 1,600 illnesses and 260 deaths in the United States annually, listeriosis ranks third in total number of deaths among foodborne bacterial pathogens, with fatality rates exceeding even '' Salmonella'' spp. and ''Clostridium botulinum''. In the European Union, listeriosis follows an upward trend that began in 2008, causing 2,161 confirmed cases and 210 reported deaths in 2014, 16% more than in 2013. Listeriosis mortality rates are also higher in the EU than for other foodborne pathogens. ''Listeria monocytogenes'' is a Gram-positive bacterium, in the phylum Bacillota, n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lecithinase
Lecithinase is a type of phospholipase that acts upon lecithin. It can be produced by ''Clostridium perfringens'', ''Staphylococcus aureus'', ''Pseudomonas aeruginosa'' or ''Listeria monocytogenes''. ''C. perfringens'' alpha toxin (lecithinase) causes myonecrosis and hemolysis Hemolysis or haemolysis (), also known by several other names, is the rupturing ( lysis) of red blood cells (erythrocytes) and the release of their contents ( cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in viv .... The lecithinase of ''S. aureus'' is used in detection of coagulase-positive strains, because of high link between lecithinase activity and coagulase activity. References EC 3.1.4 {{biochem-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clostridium Bifermentans
''Paraclostridium bifermentans'', formerly known as ''Clostridium bifermentans'' and abbreviated CLOBI, is an anaerobic, motile, gram-positive bacterium. Toxins and mosquito larvae A certain subspecies, ''Clostridium bifermentans'' subsp. Malaysia, was the first anaerobic bacterium known to kill mosquito larvae. The subspecies was part of a collection at the Institute for Medical Research, Malaysia. A biochemical analysis found that the mosquitocidal cry toxin is coded by four genes in an operon: cry16Aa, cry17Aa, cbm17.1, and cbm17.2. When the four genes were individually expressed, none of the four proteins encoded exhibited mosquitocidal activity. This suggests that the toxicity requires four proteins cooperating as a complex to take effect. A single promoter was found upstream of the four genes, indicating that the four were likely to be expressed simultaneously. The half-life of toxicity was about one day and the toxin was unstable in high temperature. Although ''C. biferment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphatidylinositol
Phosphatidylinositol (or Inositol Phospholipid) consists of a family of lipids as illustrated on the right, where red is x, blue is y, and black is z, in the context of independent variation, a class of the phosphatidylglycerides. In such molecules the isomer of the inositol group is assumed to be the myo- conformer unless otherwise stated. Typically phosphatidylinositols form a minor component on the cytosolic side of eukaryotic cell membranes. The phosphate group gives the molecules a negative charge at physiological pH. The form of phosphatidylinositol comprising the isomer ''muco''-inositol acts as a sensory receptor in the taste function of the sensory system. In this context it is often referred to as PtdIns, but that does not imply any molecular difference from phosphatidylinositols comprising the myo- conformers of inositol. The phosphatidylinositol can be phosphorylated to form phosphatidylinositol phosphate (PI-4-P, referred to as PIP in close context or inform ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clostridium
''Clostridium'' is a genus of anaerobic, Gram-positive bacteria. Species of ''Clostridium'' inhabit soils and the intestinal tract of animals, including humans. This genus includes several significant human pathogens, including the causative agents of botulism and tetanus. It also formerly included an important cause of diarrhea, ''Clostridioides difficile'', which was reclassified into the ''Clostridioides'' genus in 2016. History In the late 1700s, Germany experienced a number of outbreaks of an illness that seemed connected to eating certain sausages. In 1817, the German neurologist Justinus Kerner detected rod-shaped cells in his investigations into this so-called sausage poisoning. In 1897, the Belgian biology professor Emile van Ermengem published his finding of an endospore-forming organism he isolated from spoiled ham. Biologists classified van Ermengem's discovery along with other known gram-positive spore formers in the genus ''Bacillus''. This classification prese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphingomyelin
Sphingomyelin (SPH, ˌsfɪŋɡoˈmaɪəlɪn) is a type of sphingolipid found in animal cell membranes, especially in the membranous myelin sheath that surrounds some nerve cell axons. It usually consists of phosphocholine and ceramide, or a ethanolamine, phosphoethanolamine head group; therefore, sphingomyelins can also be classified as sphingophospholipids. In humans, SPH represents ~85% of all sphingolipids, and typically make up 10–20 mol % of plasma membrane lipids. Sphingomyelin was first isolated by Germans, German chemist Johann Ludwig Wilhelm Thudichum, Johann L.W. Thudicum in the 1880s. The structure of sphingomyelin was first reported in 1927 as N-acyl-sphingosine-1-phosphorylcholine. Sphingomyelin content in mammals ranges from 2 to 15% in most tissues, with higher concentrations found in nerve tissues, red blood cells, and the ocular lenses. Sphingomyelin has significant structural and functional roles in the cell. It is a plasma membrane component and parti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphatidylcholine
Phosphatidylcholines (PC) are a class of phospholipids that incorporate choline as a headgroup. They are a major component of biological membranes and can be easily obtained from a variety of readily available sources, such as egg yolk or soybeans, from which they are mechanically or chemically extracted using hexane. They are also a member of the lecithin group of yellow-brownish fatty substances occurring in animal and plant tissues. Dipalmitoyl phosphatidylcholine (a.k.a. lecithin) is a major component of pulmonary surfactant and is often used in the L/S ratio to calculate fetal lung maturity. While phosphatidylcholines are found in all plant and animal cells, they are absent in the membranes of most bacteria, including ''Escherichia coli''. Purified phosphatidylcholine is produced commercially. The name ''lecithin'' was derived from Greek λέκιθος, ''lekithos'' 'egg yolk' by Theodore Nicolas Gobley, a French chemist and pharmacist of the mid-19th century, who appli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_409-14%2C_Figure_1.png "Click for more on -> Listeria Monocytogenes")
