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Phytoalexins
Phytoalexins are antimicrobial substances, some of which are antioxidative as well. They are defined, not by their having any particular chemical structure or character, but by the fact that they are defensively synthesized ''de novo'' by plants that produce the compounds rapidly at sites of pathogen infection. In general phytoalexins are broad spectrum inhibitors; they are chemically diverse, and different chemical classes of compounds are characteristic of particular plant taxa. Phytoalexins tend to fall into several chemical classes, including terpenoids, glycosteroids and alkaloids, however the term applies to any phytochemicals that are induced by microbial infection. Function Phytoalexins are produced in plants to act as toxins to the attacking organism. They may puncture the cell wall, delay maturation, disrupt metabolism or prevent reproduction of the pathogen in question. Their importance in plant defense is indicated by an increase in susceptibility of plant tissue t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capsidiol
Capsidiol is a terpenoid compound that accumulates in tobacco ''Nicotiana tabacum'' and chili pepper ''Capsicum annuum'' in response to fungal infection.Maldonado-Bonilla LD, Betancourt-Jiménez M,Lozoya-Gloria E (2008) "Local and systemic gene expression of sesquiterpene phytoalexin biosynthetic enzymes in plant leaves". ''European J. Plant Path.'' 121(4), 439-449. Capsidiol is categorized under the broad term of phytoalexin, a class of low molecular weight plant secondary metabolites that are produced during infection. Phytoalexins are also characterized as a part of a two pronged response to infection which involves a short term response consisting of production of free radicals near the site of infection and a long term response involving the production of hormones and an increase in enzymes to biosynthesize phyoalexins such as capsidiol. Mechanism of production Capsidiol is produced in the pepper fruit ''Capsicum annuum'' or tobacco ''Nicotiana tabacum'' after infe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allixin
Allixin is a phytoalexin found in garlic (''Allium sativum'') bulbs. It was first isolated and characterized in 1989. When garlic is stored for long periods of time, it can form visible accumulations of crystalline allixin on its surface, particularly in areas where tissue has become necrotic. After 2 years of storage, the amount of allixin accumulated can approach 1% of the dry weight of the cloves. Since allixin has weak antimicrobial activity, these high concentrations are thought to be produced by the garlic bulb to protect itself from further damage from microorganisms. Since allixin is found in high concentrations in garlic, there has been scientific interest in determining if it is responsible for any of the known health benefits of garlic. As a result of ongoing research, a variety of biological activities have been attributed to allixin. Pharmaceutical drug discovery research based on derivatives of allixin has followed. Laboratory synthesis Two laboratory synthe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Systemic Acquired Resistance
Systemic acquired resistance (SAR) is a "whole-plant" resistance response that occurs following an earlier localized exposure to a pathogen. SAR is analogous to the innate immune system found in animals, and although there are many shared aspects between the two systems, it is thought to be a result of convergent evolution. The systemic acquired resistance response is dependent on the plant hormone, salicylic acid. Discovery While, it has been recognized since at least the 1930s that plants have some kind of induced immunity to pathogens, the modern study of systemic acquired resistance began in the 1980s when the invention of new tools allowed scientists to probe the molecular mechanisms of SAR.Ryals, J., U. Neuenschwander, M. Willits, A. Molina, H. Steiner, and M. Hunt. 1996. Systemic Acquired Resistance. Plant Cell 8:1809–1819. A number of 'marker genes' were characterized in the 80s and 90s which are strongly induced as part of the SAR response. These pathogenesis-related p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
7,12-Dimethylbenz(a)anthracene
7,12-Dimethylbenz 'a''nthracene (DMBA) is an immunosuppressor and a powerful organ-specific laboratory carcinogen. DMBA is widely used in many research laboratories studying cancer. DMBA serves as a tumor initiator. Tumor promotion Tumor promotion is a process in carcinogenesis by which various factors permit the descendants of a single initiated cell to survive and expand in number, i.e. to resist apoptosis and to undergo clonal growth. This is a step toward tumor progressi ... can be induced with treatments of 12-''O''-tetradecanoylphorbol-13-acetate (TPA) in some models of two-stage carcinogenesis. This allows for a greatly accelerated rate of tumor growth, making many cancer studies possible. References {{DEFAULTSORT:Dimethylbenz(a)anthracene, 7,12- Polycyclic aromatic hydrocarbons Carcinogens Anthracenes Immunosuppressants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
12-O-Tetradecanoylphorbol-13-acetate
12-''O''-Tetradecanoylphorbol-13-acetate (TPA), also commonly known as tetradecanoylphorbol acetate, tetradecanoyl phorbol acetate, and phorbol 12-myristate 13-acetate (PMA) is a diester of phorbol. It is a potent tumor promoter often employed in biomedical research to activate the signal transduction enzyme protein kinase C (PKC). The effects of TPA on PKC result from its similarity to one of the natural activators of classic PKC isoforms, diacylglycerol. TPA is a small molecule drug. In ROS biology, superoxide was identified as the major reactive oxygen species induced by TPA/PMA but not by ionomycin in mouse macrophages. Thus, TPA/PMA has been routinely used as an inducer for endogenous superoxide production. TPA is also being studied as a drug in the treatment of hematologic cancer TPA has a specific use in cancer diagnostics as a B-cell specific mitogen in cytogenetic testing. To view the chromosomes, a cytogenetic test requires dividing cells. TPA is used to stimulate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tumor
A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists in growing abnormally, even if the original trigger is removed. This abnormal growth usually forms a mass, when it may be called a tumor. ICD-10 classifies neoplasms into four main groups: benign neoplasms, in situ neoplasms, malignant neoplasms, and neoplasms of uncertain or unknown behavior. Malignant neoplasms are also simply known as cancers and are the focus of oncology. Prior to the abnormal growth of tissue, as neoplasia, cells often undergo an abnormal pattern of growth, such as metaplasia or dysplasia. However, metaplasia or dysplasia does not always progress to neoplasia and can occur in other conditions as well. The word is from Ancient Greek 'new' and 'formation, creation'. Types A neoplasm can be benign, potentially m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aflatoxin
Aflatoxins are various poisonous carcinogens and mutagens that are produced by certain molds, particularly ''Aspergillus'' species. The fungi grow in soil, decaying vegetation and various staple foodstuffs and commodities such as hay, sweetcorn, wheat, millet, sorghum, cassava, rice, chili peppers, cottonseed, peanuts, tree nuts, sesame seeds, sunflower seeds, and various spices. In short, the relevant fungi grow on almost any crop or food. When such contaminated food is processed or consumed, the aflatoxins enter the general food supply. They have been found in both pet and human foods, as well as in feedstocks for agricultural animals. Animals fed contaminated food can pass aflatoxin transformation products into eggs, milk products, and meat. For example, contaminated poultry feed is the suspected source of aflatoxin-contaminated chicken meat and eggs in Pakistan. Children are particularly affected by aflatoxin exposure, which is associated with stunted growth, delayed de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stress (mechanics)
In continuum mechanics, stress is a physical quantity. It is a quantity that describes the magnitude of forces that cause deformation. Stress is defined as ''force per unit area''. When an object is pulled apart by a force it will cause elongation which is also known as deformation, like the stretching of an elastic band, it is called tensile stress. But, when the forces result in the compression of an object, it is called compressive stress. It results when forces like tension or compression act on a body. The greater this force and the smaller the cross-sectional area of the body on which it acts, the greater the stress. Therefore, stress is measured in newton per square meter (N/m2) or pascal (Pa). Stress expresses the internal forces that neighbouring particles of a continuous material exert on each other, while strain is the measure of the deformation of the material. For example, when a solid vertical bar is supporting an overhead weight, each particle in the bar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Garlic
Garlic (''Allium sativum'') is a species of bulbous flowering plant in the genus '' Allium''. Its close relatives include the onion, shallot, leek, chive, Welsh onion and Chinese onion. It is native to South Asia, Central Asia and northeastern Iran and has long been used as a seasoning worldwide, with a history of several thousand years of human consumption and use. It was known to ancient Egyptians and has been used as both a food flavoring and a traditional medicine. China produces 76% of the world's supply of garlic. Etymology The word ''garlic'' derives from Old English, ''garlēac'', meaning ''gar'' (spear) and leek, as a 'spear-shaped leek'. Description ''Allium sativum'' is a perennial flowering plant growing from a bulb. It has a tall, erect flowering stem that grows up to . The leaf blade is flat, linear, solid, and approximately wide, with an acute apex. The plant may produce pink to purple flowers from July to September in the Northern Hemisphere. The bulb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrone
Pyrones or pyranones are a class of heterocyclic chemical compounds. They contain an unsaturated six-membered ring containing one oxygen atom and a ketone functional group. There are two isomers denoted as 2-pyrone and 4-pyrone. The 2-pyrone (or α-pyrone) structure is found in nature as part of the coumarin ring system. 4-Pyrone (or γ-pyrone) is found in some natural chemical compounds such as chromone, maltol and kojic acid. See also * Furanone 2-Furanone is a heterocyclic organic compound. It is also known as γ-crotonolactone (GCL), as it is formally the lactone derived from γ-hydroxyisocrotonic acid. The chemical is colloquially called "butenolide", and is the parent structure for th ..., which has one fewer carbon atom in the ring. References {{heterocyclic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vector (epidemiology)
In epidemiology, a disease vector is any living agent that carries and transmits an infectious pathogen to another living organism; agents regarded as vectors are organisms, such as parasites or microbes. The first major discovery of a disease vector came from Ronald Ross in 1897, who discovered the malaria pathogen when he dissected a mosquito. Arthropods Arthropods form a major group of pathogen vectors with mosquitoes, flies, sand flies, lice, fleas, ticks, and mites transmitting a huge number of pathogens. Many such vectors are haematophagous, which feed on blood at some or all stages of their lives. When the insects feed on blood, the pathogen enters the blood stream of the host. This can happen in different ways. The '' Anopheles'' mosquito, a vector for malaria, filariasis, and various arthropod-borne-viruses ( arboviruses), inserts its delicate mouthpart under the skin and feeds on its host's blood. The parasites the mosquito carries are usually located in its sal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salicylic Acid
Salicylic acid is an organic compound with the formula HOC6H4CO2H. A colorless, bitter-tasting solid, it is a precursor to and a metabolite of aspirin (acetylsalicylic acid). It is a plant hormone, and has been listed by the EPA Toxic Substances Control Act (TSCA) Chemical Substance Inventory as an experimental teratogen. The name is from Latin '' salix'' for willow tree. It is an ingredient in some anti-acne products. Salts and esters of salicylic acid are known as salicylates. Uses Medicine Salicylic acid as a medication is commonly used to remove the outer layer of the skin. As such, it is used to treat warts, psoriasis, acne vulgaris, ringworm, dandruff, and ichthyosis. Similar to other hydroxy acids, salicylic acid is an ingredient in many skincare products for the treatment of seborrhoeic dermatitis, acne, psoriasis, calluses, Corn (medicine), corns, keratosis pilaris, acanthosis nigricans, ichthyosis, and warts. Uses in manufacturing Salicylic acid is used as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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