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Oleosin
Oleosins are structural proteins found in vascular plant oil bodies and in plant cells. Oil bodies are not considered organelles because they have a single layer membrane and lack the pre-requisite double layer membrane in order to be considered an organelle. They are found in plant parts with high oil content that undergo extreme desiccation as part of their maturation process, and help stabilize the bodies. Components Oleosins are proteins of 16 kDa to 24 kDa and are composed of three domains: an N-terminal hydrophilic region of variable length (from 30 to 60 residues); a central hydrophobic domain of about 70 residues and a C-terminal amphipathic region of variable length (from 60 to 100 residues). The central hydrophobic domain is proposed to be made up of beta-strand structure and to interact with the lipids. It is the only domain whose sequence is conserved. Models show oleosins having a hairpin-like hydrophobic shape that is inserted inside the triacylglyceride (TAG), w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tapetum (botany)
The tapetum is a specialised layer of nutritive cells found within the anther, of flowering plants, where it is located between the sporangenous tissue and the anther wall. Tapetum is important for the nutrition and development of pollen grains, as well as a source of precursors for the pollen coat.P.L. Polowick, V.K. Sawhney 1993Differentiation of the Tapetum During Microsporogenesis in Tomato (Lycopersicon esculentum Mill.), with Special Reference to the Tapetal Cell Wall Annals of Botany, Volume 72, Issue 6, December 1993, Pages 595–605 The cells are usually bigger and normally have more than one nucleus per cell. As the sporogenous cells undergo mitosis, the nuclei of tapetal cells also divide. Sometimes, this mitosis is not normal due to which many cells of mature tapetum become multinucleate. Sometimes polyploidy and polyteny can also be seen. The unusually large nuclear constitution of the tapetum helps it in providing nutrients and regulatory molecules to the forming po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centrifugation
Centrifugation is a mechanical process which involves the use of the centrifugal force to separate particles from a solution according to their size, shape, density, medium viscosity and rotor speed. The denser components of the mixture migrate away from the axis of the centrifuge, while the less dense components of the mixture migrate towards the axis. Chemists and biologists may increase the effective gravitational force of the test tube so that the precipitate (pellet) will travel quickly and fully to the bottom of the tube. The remaining liquid that lies above the precipitate is called a supernatant or supernate. There is a correlation between the size and density of a particle and the rate that the particle separates from a heterogeneous mixture, when the only force applied is that of gravity. The larger the size and the larger the density of the particles, the faster they separate from the mixture. By applying a larger effective gravitational force to the mixture, like a ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protease
A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products. They do this by cleaving the peptide bonds within proteins by hydrolysis, a reaction where water breaks bonds. Proteases are involved in many biological functions, including digestion of ingested proteins, protein catabolism (breakdown of old proteins), and cell signaling. In the absence of functional accelerants, proteolysis would be very slow, taking hundreds of years. Proteases can be found in all forms of life and viruses. They have independently evolved multiple times, and different classes of protease can perform the same reaction by completely different catalytic mechanisms. Hierarchy of proteases Based on catalytic residue Proteases can be classified into seven broad groups: * Serine protease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fusion Protein
Fusion proteins or chimeric (kī-ˈmir-ik) proteins (literally, made of parts from different sources) are proteins created through the joining of two or more genes that originally coded for separate proteins. Translation of this ''fusion gene'' results in a single or multiple polypeptides with functional properties derived from each of the original proteins. ''Recombinant fusion proteins'' are created artificially by recombinant DNA technology for use in biological research or therapeutics. '' Chimeric'' or ''chimera'' usually designate hybrid proteins made of polypeptides having different functions or physico-chemical patterns. ''Chimeric mutant proteins'' occur naturally when a complex mutation, such as a chromosomal translocation, tandem duplication, or retrotransposition creates a novel coding sequence containing parts of the coding sequences from two different genes. Naturally occurring fusion proteins are commonly found in cancer cells, where they may function as oncoproteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recombinant DNA
Recombinant DNA (rDNA) molecules are DNA molecules formed by laboratory methods of genetic recombination (such as molecular cloning) that bring together genetic material from multiple sources, creating sequences that would not otherwise be found in the genome. Recombinant DNA is the general name for a piece of DNA that has been created by combining at least two fragments from two different sources. Recombinant DNA is possible because DNA molecules from all organisms share the same chemical structure, and differ only in the nucleotide sequence within that identical overall structure. Recombinant DNA molecules are sometimes called chimeric DNA, because they can be made of material from two different species, like the mythical chimera. R-DNA technology uses palindromic sequences and leads to the production of sticky and blunt ends. The DNA sequences used in the construction of recombinant DNA molecules can originate from any species. For example, plant DNA may be joined to bacter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmetics
Cosmetics are constituted mixtures of chemical compounds derived from either natural sources, or synthetically created ones. Cosmetics have various purposes. Those designed for personal care and skin care can be used to cleanse or protect the body or skin. Cosmetics designed to enhance or alter one's appearance (makeup) can be used to conceal blemishes, enhance one's natural features (such as the eyebrows and eyelashes), add color to a person's face, or change the appearance of the face entirely to resemble a different person, creature or object. Cosmetics can also be designed to add fragrance to the body. Definition and etymology The word ''cosmetics'' derives from the Greek (), meaning "technique of dress and ornament", from (), "skilled in ordering or arranging" and that from (), meaning "order" and "ornament". Cosmetics are constituted from a mixture of chemical compounds derived from either natural sources, or synthetically created ones. Legal definition T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dietary Supplement
A dietary supplement is a manufactured product intended to supplement one's diet by taking a pill, capsule, tablet, powder, or liquid. A supplement can provide nutrients either extracted from food sources or that are synthetic in order to increase the quantity of their consumption. The class of nutrient compounds includes vitamins, minerals, fiber, fatty acids, and amino acids. Dietary supplements can also contain substances that have not been confirmed as being essential to life, but are marketed as having a beneficial biological effect, such as plant pigments or polyphenols. Animals can also be a source of supplement ingredients, such as collagen from chickens or fish for example. These are also sold individually and in combination, and may be combined with nutrient ingredients. The European Commission has also established harmonized rules to help insure that food supplements are safe and appropriately labeled. Creating an industry estimated to have a 2020 value of $ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaphylaxis
Anaphylaxis is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of use of emergency medication on site. It typically causes more than one of the following: an itchy rash, throat closing due to swelling which can obstruct or stop breathing; severe tongue swelling which can also interfere with or stop breathing; shortness of breath, vomiting, lightheadedness, loss of consciousness, low blood pressure, and medical shock. These symptoms typically start in minutes to hours and then increase very rapidly to life-threatening levels. Urgent medical treatment is required to prevent serious harm or death, even if the patient has used an epipen or has taken other medications in response, and even if symptoms appear to be improving. Common causes include allergies to insect bites and stings, allergies to foods – including nuts, milk, fish, shellfish, eggs and some fresh fruits or dried fruits; a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dermatitis
Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can vary from small to covering the entire body. Dermatitis is often called eczema, and the difference between those terms is not standardized. The exact cause of the condition is often unclear. Cases may involve a combination of allergy and poor venous return. The type of dermatitis is generally determined by the person's history and the location of the rash. For example, irritant dermatitis often occurs on the hands of those who frequently get them wet. Allergic contact dermatitis occurs upon exposure to an allergen, causing a hypersensitivity reaction in the skin. Prevention of atopic dermatitis is typically with essential fatty acids, and may be treated with moisturizers and steroid creams. The steroid creams should generally be of mid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sesame
Sesame ( or ; ''Sesamum indicum'') is a flowering plant in the genus ''Sesamum'', also called benne. Numerous wild relatives occur in Africa and a smaller number in India. It is widely naturalized in tropical regions around the world and is cultivated for its edible seeds, which grow in pods. World production in 2018 was , with Sudan, Myanmar, and India as the largest producers. Sesame seed is one of the oldest oilseed crops known, domesticated well over 3,000 years ago. ''Sesamum'' has many other species, most being wild and native to sub-Saharan Africa. ''S. indicum,'' the cultivated type, originated in India. It tolerates drought conditions well, growing where other crops fail. Sesame has one of the highest oil contents of any seed. With a rich, nutty flavor, it is a common ingredient in cuisines around the world. Like other foods, it can trigger allergic reactions in some people. Etymology The word "sesame" is from Latin ''sesamum'' and Greek σήσαμον : ''sēsamon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peanut
The peanut (''Arachis hypogaea''), also known as the groundnut, goober (US), pindar (US) or monkey nut (UK), is a legume crop grown mainly for its edible Seed, seeds. It is widely grown in the tropics and subtropics, important to both small and large commercial producers. It is classified as both a grain legume and, due to its high oil content, an oil crop. World annual production of shelled peanuts was 44 million tonnes in 2016, led by China with 38% of the world total. Atypically among legume crop plants, peanut pods develop underground (geocarpy) rather than above ground. With this characteristic in mind, the botanist Carl Linnaeus gave peanuts the specific epithet ''hypogaea'', which means "under the earth." The peanut belongs to the botanical Family (biology), family Fabaceae (or Leguminosae), commonly known as the legume, bean, or pea family. Like most other legumes, peanuts harbor symbiotic Nitrogen fixation, nitrogen-fixing bacteria in root nodules. The capacity to fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
