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Thionins
Thionins are a family of small proteins found solely in higher plants. Typically, a thionin consists of 45–48 amino acid residues. 6–8 of these are cysteine forming 3–4 disulfide bonds. They include phoratoxins and viscotoxins. Alpha- and beta- thionins are related to each other. The gamma thionins have a superficially similar structure but are an unrelated class of protein, now called plant defensins. Activity The proteins are toxic to animal cells, presumably attacking the cell membrane and rendering it permeable: this results in the inhibition of sugar uptake and allows potassium and phosphate ions, proteins, and nucleotides to leak from cells. Thionins are mainly found in seeds where they may act as a defence against consumption by animals. A barley (''Hordeum vulgare'') leaf thionin that is highly toxic to plant pathogens and is involved in the mechanism of plant defence against microbial infections has also been identified. The hydrophobic protein crambin from the A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Thionin
Plant defensins (formerly ''gamma-thionins)'' are a family of small, cysteine-rich defensins found in plants that serve to defend them against pathogens and parasites. History The first plant defensins were discovered in barley and wheat in 1990 and were initially designated as a γ-thionins. In 1995 the name was changed to 'plant defensin' when it was identified that they are evolutionarily unrelated to other thionins and were more similar to defensins from insects and mammals. Function Plant defensins are a large component of the plant innate immune system. A plant genome typically contains large numbers of different defensin genes that vary in their efficacies against different pathogens and the amount they are expressed in different tissues. Antimicrobial activity The modes of action of different defensins depends on the type of fungus they are interacting with. Most characterized plant defensins are antimicrobial peptides. Both antifungal and antibacterial plant def ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Thionin
Plant defensins (formerly ''gamma-thionins)'' are a family of small, cysteine-rich defensins found in plants that serve to defend them against pathogens and parasites. History The first plant defensins were discovered in barley and wheat in 1990 and were initially designated as a γ-thionins. In 1995 the name was changed to 'plant defensin' when it was identified that they are evolutionarily unrelated to other thionins and were more similar to defensins from insects and mammals. Function Plant defensins are a large component of the plant innate immune system. A plant genome typically contains large numbers of different defensin genes that vary in their efficacies against different pathogens and the amount they are expressed in different tissues. Antimicrobial activity The modes of action of different defensins depends on the type of fungus they are interacting with. Most characterized plant defensins are antimicrobial peptides. Both antifungal and antibacterial plant def ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phoratoxin
Phoratoxins are a group of peptide toxins that belong to the family of thionins, a subdivision of small plant toxins (5000 kD MW). Phoratoxins are proteins present in the leaves and branches of the ''Phoradendron'', commonly known as the American variant of the mistletoe, a plant commonly used as decoration during the festive season. The berries of the mistletoe do not contain phoratoxins, making them less toxic compared to other parts of the plant. The toxicity of the mistletoe is dependent on the host tree, since mistletoe is known to be a semi-parasite. The host tree provides fixed inorganic nitrogen compounds necessary for the mistletoe to synthesize phoratoxins. Viscotoxins are similar plant thionins produced from the leaves and stems of the European mistletoe (''Viscum album''). History The history of phoratoxin is filled with myths, legends, and other magical stories. Mistletoe is a semi-parasitic plant occasionally using oak trees as their host. To historic peoples such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viscotoxin
Phoratoxins are a group of peptide toxins that belong to the family of thionins, a subdivision of small plant toxins (5000 kD MW). Phoratoxins are proteins present in the leaves and branches of the ''Phoradendron'', commonly known as the American variant of the mistletoe, a plant commonly used as decoration during the festive season. The berries of the mistletoe do not contain phoratoxins, making them less toxic compared to other parts of the plant. The toxicity of the mistletoe is dependent on the host tree, since mistletoe is known to be a semi-parasite. The host tree provides fixed inorganic nitrogen compounds necessary for the mistletoe to synthesize phoratoxins. Viscotoxins are similar plant thionins produced from the leaves and stems of the European mistletoe (''Viscum album''). History The history of phoratoxin is filled with myths, legends, and other magical stories. Mistletoe is a semi-parasitic plant occasionally using oak trees as their host. To historic peoples such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crambin
Crambin is a small seed storage protein from the Abyssinian cabbage. It belongs to thionins Thionins are a family of small proteins found solely in higher plants. Typically, a thionin consists of 45–48 amino acid residues. 6–8 of these are cysteine forming 3–4 disulfide bonds. They include phoratoxins and viscotoxins. Alpha- and .... It has 46 residues (amino acids). It has been extensively studied by X-ray crystallography since its crystals are unique and diffract to a resolution of 0.48 Å. Neutron scattering measurements are available also at a resolution of 1.1 Å.; References {{reflist Proteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crambin
Crambin is a small seed storage protein from the Abyssinian cabbage. It belongs to thionins Thionins are a family of small proteins found solely in higher plants. Typically, a thionin consists of 45–48 amino acid residues. 6–8 of these are cysteine forming 3–4 disulfide bonds. They include phoratoxins and viscotoxins. Alpha- and .... It has 46 residues (amino acids). It has been extensively studied by X-ray crystallography since its crystals are unique and diffract to a resolution of 0.48 Å. Neutron scattering measurements are available also at a resolution of 1.1 Å.; References {{reflist Proteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Higher Plants
Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They also have a specialized non-lignified tissue (the phloem) to conduct products of photosynthesis. Vascular plants include the clubmosses, horsetails, ferns, gymnosperms (including conifers), and angiosperms (flowering plants). Scientific names for the group include Tracheophyta, Tracheobionta and Equisetopsida ''sensu lato''. Some early land plants (the rhyniophytes) had less developed vascular tissue; the term eutracheophyte has been used for all other vascular plants, including all living ones. Historically, vascular plants were known as "higher plants", as it was believed that they were further evolved than other plants due to being more complex organisms. However, this is an antiquated remnant of the obsolete scala naturae, and the term ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss, and a change in bowel movements. While these symptoms may indicate cancer, they can also have other causes. Over 100 types of cancers affect humans. Tobacco use is the cause of about 22% of cancer deaths. Another 10% are due to obesity, poor diet, lack of physical activity or excessive drinking of alcohol. Other factors include certain infections, exposure to ionizing radiation, and environmental pollutants. In the developing world, 15% of cancers are due to infections such as ''Helicobacter pylori'', hepatitis B, hepatitis C, human papillomavirus infection, Epstein–Barr virus and human immunodeficiency virus (HIV). These factors act, at least partly, by changing the genes of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peripheral Membrane Proteins
Peripheral membrane proteins, or extrinsic membrane proteins, are membrane proteins that adhere only temporarily to the biological membrane with which they are associated. These proteins attach to integral membrane proteins, or penetrate the peripheral regions of the lipid bilayer. The regulatory protein subunits of many ion channels and transmembrane receptors, for example, may be defined as peripheral membrane proteins. In contrast to integral membrane proteins, peripheral membrane proteins tend to collect in the water-soluble component, or fraction, of all the proteins extracted during a protein purification procedure. Proteins with GPI anchors are an exception to this rule and can have purification properties similar to those of integral membrane proteins. The reversible attachment of proteins to biological membranes has shown to regulate cell signaling and many other important cellular events, through a variety of mechanisms. For example, the close association between many enzy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antimicrobial Peptide
Antimicrobial peptides (AMPs), also called host defence peptides (HDPs) are part of the innate immune response found among all classes of life. Fundamental differences exist between prokaryotic and eukaryotic cells that may represent targets for antimicrobial peptides. These peptides are potent, broad spectrum antibiotics which demonstrate potential as novel therapeutic agents. Antimicrobial peptides have been demonstrated to kill Gram negative and Gram positive bacteria, enveloped viruses, fungi and even transformed or cancerous cells. Unlike the majority of conventional antibiotics it appears that antimicrobial peptides frequently destabilize biological membranes, can form transmembrane channels, and may also have the ability to enhance immunity by functioning as immunomodulators. Structure Antimicrobial peptides are a unique and diverse group of molecules, which are divided into subgroups on the basis of their amino acid composition and structure. Antimicrobial peptides are ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crambe Abyssinica
''Crambe abyssinica'' is an annual oilseed crop of the family Brassicaceae. It is mainly cultivated due to the high levels of erucic acid that are contained in its seeds. The crambe oil is used for industrial purposes and its side products can be partly used as animal feed. Botany ''Crambe abyssinica'' has its origins in eastern Africa and was domesticated in the Mediterranean region. It grows up to a height between , depending on field conditions. Its cropping cycle is rather short, ranging from 90 to 100 days. Usually, its straight stalk is moderately branched and its leaves are of an oval shape. The plant's flowers are small and white, arranged in racemes and have four free sepals, four free alternating petals, two shorter and four longer free stamens, what is typical for Brassicaceae. Mostly, these flowers are self-pollinated, but some cases of cross-pollination have been observed. Its indehiscent fruits enclose only one spherical seed that contains around 26% protein, 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drugs
A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via inhalation, injection, smoking, ingestion, absorption via a patch on the skin, suppository, or dissolution under the tongue. In pharmacology, a drug is a chemical substance, typically of known structure, which, when administered to a living organism, produces a biological effect. A pharmaceutical drug, also called a medication or medicine, is a chemical substance used to treat, cure, prevent, or diagnose a disease or to promote well-being. Traditionally drugs were obtained through extraction from medicinal plants, but more recently also by organic synthesis. Pharmaceutical drugs may be used for a limited duration, or on a regular basis for chronic disorders. Pharmaceutical drugs are often classified into drug classes—groups of related ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
