|
Photostatin
Photostatins are inhibitors that can be switched on and off ''in vivo'' by visible light, to optically control microtubule dynamics. Photostatins are a form of photopharmacology. As a cell prepares to divide, its microtubules, arrange themselves into a spindle that permits its chromosomes to split into two bundles. These bundles become the nuclei of the daughter cells, Out-of-control cell replication is the underlying cause of cancer, developing drugs that interfere with microtubule activity offers one potential therapeutic approach. They can operate microtubule dynamics with a subsecond response time and control mitosis in living organisms with single-cell spatial precision. Most microtubule inhibitors affect both cancerous and healthy cells, requiring lower doses to avoid severe side effects. Because photostatins are inactive in the absence of light, they only affect cells that are illuminated. Focusing light on tumors directs their activities to appropriate targets with fewer s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microtubule
Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells. Microtubules can be as long as 50 micrometres, as wide as 23 to 27 nanometer, nm and have an inner diameter between 11 and 15 nm. They are formed by the polymerization of a Protein dimer, dimer of two globular proteins, Tubulin#Eukaryotic, alpha and beta tubulin into #Structure, protofilaments that can then associate laterally to form a hollow tube, the microtubule. The most common form of a microtubule consists of 13 protofilaments in the tubular arrangement. Microtubules play an important role in a number of cellular processes. They are involved in maintaining the structure of the cell and, together with microfilaments and intermediate filaments, they form the cytoskeleton. They also make up the internal structure of cilia and flagella. They provide platforms for intracellular transport and are involved in a variety of cellular processes, in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photopharmacology
Photopharmacology is an emerging multidisciplinary field that combines photochemistry and pharmacology. Built upon the ability of light to change the pharmacokinetics and pharmacodynamics of bioactive molecules, it aims at regulating the activity of drugs in vivo by using light. The light-based modulation is achieved by incorporating molecular photoswitches such as azobenzene and diarylethenes or photocages such as o-nitrobenzyl, coumarin, and BODIPY compounds into the pharmacophore. This selective activation of the biomolecules helps prevent or minimize off-target activity and systemic side effects. Moreover, light being the regulatory element offers additional advantages such as the ability to be delivered with high spatiotemporal precision, low to negligible toxicity, and the ability to be controlled both qualitatively and quantitatively by tuning its wavelength and intensity. History Though photopharmacology is a relatively new field, the concept of using light in therapeutic a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosomes
A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most important of these proteins are the histones. Aided by chaperone proteins, the histones bind to and condense the DNA molecule to maintain its integrity. These eukaryotic chromosomes display a complex three-dimensional structure that has a significant role in transcriptional regulation. Normally, chromosomes are visible under a light microscope only during the metaphase of cell division, where all chromosomes are aligned in the center of the cell in their condensed form. Before this stage occurs, each chromosome is duplicated ( S phase), and the two copies are joined by a centromere—resulting in either an X-shaped structure if the centromere is located equatorially, or a two-armed structure if the centromere is located distally; the joined ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Nucleus
The cell nucleus (; : nuclei) is a membrane-bound organelle found in eukaryote, eukaryotic cell (biology), cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have #Anucleated_cells, no nuclei, and a few others including osteoclasts have Multinucleate, many. The main structures making up the nucleus are the nuclear envelope, a double membrane that encloses the entire organelle and isolates its contents from the cellular cytoplasm; and the nuclear matrix, a network within the nucleus that adds mechanical support. The cell nucleus contains nearly all of the cell's genome. Nuclear DNA is often organized into multiple chromosomes – long strands of DNA dotted with various proteins, such as histones, that protect and organize the DNA. The genes within these chromosomes are Nuclear organization, structured in such a way to promote cell function. The nucleus maintains the integrity of genes and controls the activities of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitosis
Mitosis () is a part of the cell cycle in eukaryote, eukaryotic cells in which replicated chromosomes are separated into two new Cell nucleus, nuclei. Cell division by mitosis is an equational division which gives rise to genetically identical cells in which the total number of chromosomes is maintained. Mitosis is preceded by the S phase of interphase (during which DNA replication occurs) and is followed by telophase and cytokinesis, which divide the cytoplasm, organelles, and cell membrane of one cell into two new cell (biology), cells containing roughly equal shares of these cellular components. The different stages of mitosis altogether define the mitotic phase (M phase) of a cell cycle—the cell division, division of the mother cell into two daughter cells genetically identical to each other. The process of mitosis is divided into stages corresponding to the completion of one set of activities and the start of the next. These stages are preprophase (specific to plant ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combretastatin A-4
Combretastatin A-4 is a combretastatin and a stilbenoid. It can be isolated from ''Combretum afrum'', the Eastern Cape South African bushwillow tree or in '' Combretum leprosum'', the mofumbo, a species found in Brazil. Function Tubulin represents a potent target in cancer chemotherapy, given its role in cell division. Combretastatin is a naturally occurring well known tubulin polymerization inhibitor. Combretastatin A-4 comes in two stereoisomer In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in ...s ( cis (shown top right), and trans); The cis form binds much better to the 'colchicine' site on tubulin to inhibit polymerization. Derivatives Combretastatin A-4 is the active component of combretastatin A-4 phosphate, a prodrug designed to damage the vasculature (blood vessels) of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combretastatin
Combretastatin is a dihydrostilbenoid found in '' Combretum afrum''. As a class Combretastatins are a class of natural phenols. A variety of different natural combretastatin molecules are present in the bark of ''C. afrum'', commonly known as South African Bush Willow. Despite having a similar name, combretastatins are unrelated to statins, a family of cholesterol lowering drugs. Natural combretastatins Molecules that fall into the combretastatin family generally share 3 common structural features: a trimethoxy "A"-ring, a "B"-ring containing substituents often at C3' and C4', and ftenan ethene bridge between the two rings which provides necessary structural rigidity. Molecules with such an ethene bridge are also stilbenoids, molecules with a non-ethene bridge are dihydrostilbenoids. Molecules with C3' amino and hydroxyl substituents are very active, and molecules with C4' hydroxyl or methoxy substituents are also cytotoxic. Of the natural products presently known combr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South African Bushwillow
''Combretum afrum'', commonly known as Cape bushwillow, is a species of tree native to South Africa. It is endemic to the Cape Provinces. Biochemistry In ''C. afrum'', combretastatins A-1, A-4 and B-1 can be found. Taxonomy The etymology of the original species name ''caffrum'' is related to kaffir, an ethnic slur used towards black people in Africa. At the July 2024 International Botanical Congress International Botanical Congress (IBC) is an international meeting of Botany, botanists in all scientific fields, authorized by the International Association of Botanical and Mycological Societies (IABMS) and held every six years, with the locatio ..., a vote was held with the result that "''caffrum''" related names will be emended to ''afrum'' related ones, with the implementation of this happening by the end of July 2024. References * * afrum Endemic flora of the Cape Provinces Plants described in 1835 {{Myrtales-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isomer
In chemistry, isomers are molecules or polyatomic ions with identical molecular formula – that is, the same number of atoms of each element (chemistry), element – but distinct arrangements of atoms in space. ''Isomerism'' refers to the existence or possibility of isomers. Isomers do not necessarily share similar chemical property, chemical or physical property, physical properties. Two main forms of isomerism are structural isomerism, structural (or constitutional) isomerism, in which ''chemical bond, bonds'' between the atoms differ; and stereoisomerism (or spatial isomerism), in which the bonds are the same but the ''relative positions'' of the atoms differ. Isomeric relationships form a hierarchy. Two chemicals might be the same constitutional isomer, but upon deeper analysis be stereoisomers of each other. Two molecules that are the same stereoisomer as each other might be in different conformational forms or be different Isotopologue, isotopologues. The depth of analy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photopharmacology
Photopharmacology is an emerging multidisciplinary field that combines photochemistry and pharmacology. Built upon the ability of light to change the pharmacokinetics and pharmacodynamics of bioactive molecules, it aims at regulating the activity of drugs in vivo by using light. The light-based modulation is achieved by incorporating molecular photoswitches such as azobenzene and diarylethenes or photocages such as o-nitrobenzyl, coumarin, and BODIPY compounds into the pharmacophore. This selective activation of the biomolecules helps prevent or minimize off-target activity and systemic side effects. Moreover, light being the regulatory element offers additional advantages such as the ability to be delivered with high spatiotemporal precision, low to negligible toxicity, and the ability to be controlled both qualitatively and quantitatively by tuning its wavelength and intensity. History Though photopharmacology is a relatively new field, the concept of using light in therapeutic a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
