Mistletoe
Viscum album
Toxins, Biological
Loranthaceae
Viscum
Plant Lectins
Viscaceae
Nerium
Plants, Medicinal
Plant Proteins
Abies
Plant Extracts
Ricin
Lectins
Pinus sylvestris
Pseudotsuga
Fetuins
Insulin-secreting activity of the traditional antidiabetic plant Viscum album (mistletoe). (1/66)
Viscum album (mistletoe) has been documented as a traditional treatment of diabetes. In acute 20-min tests, 1-10 mg/ml aqueous extract of mistletoe evoked a stepwise 1.1- to 12.2-fold stimulation of insulin secretion from clonal pancreatic B-cells. This effect was abolished by 0.5 mM diazoxide and prior exposure to extract did not alter subsequent stimulation of insulin secretion induced by 10 mM L-alanine, thereby negating a detrimental effect on cell viability. The insulin-releasing effect of mistletoe extract was unaltered by 16.7 mM glucose, l-alanine (10 mM), 3-isobutyl-1-methylxanthine (IBMX) (1 mM), or a depolarising concentration of KCl (25 mM). The ability of extract to enhance insulin secretion did not depend upon the use of heat during extract preparation and was not mediated by lectins. These results demonstrate the presence of insulin-releasing natural product(s) in Viscum album which may contribute to the reported antidiabetic property of the plant. (+info)Selective killing of CD8+ cells with a 'memory' phenotype (CD62Llo) by the N-acetyl-D-galactosamine-specific lectin from Viscum album L. (2/66)
As reported previously by our group, among the toxic proteins from Viscum album L. only the mistletoe lectins (MLs) induce the apoptotic killing pathway in human lymphocytes. Although one may expect a homogenous distribution of carbohydrate domains on cell surface receptors for the carbohydrate binding B chains of the toxic protein, the sensitivity of cells to these B chains obviously differ. Here we report a selective killing of CD8+ CD62Llo cells from healthy individuals by the galNAc-specific ML III (and RCA60, which binds to gal and galNAc), while the gal-specific ML I was less effective. This selective killing is not sufficiently explained by protein synthesis inhibition alone, since this subset was not affected by other ribosome inhibiting proteins such as the lectin from Ricinus communis (RCA120), lectin from Abrus precatorus (APA), abrin A, and inhibitors of RNA, DNA and/or protein synthesis such as actinomycin D, mitomycin C, and cycloheximide. We conclude that CD8+ cells with 'memory' phenotype (CD62Llo) are more sensitive to the ML III-mediated killing than their CD8+ CD62Lhi counterparts, CD4+ T cells, and CD19+ B cells. These cells probably express a distinct receptor with galNAc domains that is missing or not active on CD8+ cells with a 'naive' phenotype. (+info)Accidental cell death and generation of reactive oxygen intermediates in human lymphocytes induced by thionins from Viscum album L. (3/66)
The cytotoxic mechanisms of thionins from Viscum album L., the viscotoxins, were investigated in human granulocytes and lymphocytes. The time course of viscotoxin effects indicate accidental cell death, i.e. membrane permeabilization, degradation of cytoplasm and chromatin, swelling of mitochondria with loss of their cristae, and generation of reactive oxygen intermediates within 1-2 h, followed by secondary apoptosis-associated events. The viscotoxin homologue purothionin from whole-wheat flour and viscotoxin B, however, did not induce cell death in cultured lymphocytes. Cytotoxicity of cationic and amphipathic viscotoxin was prevented only by cleavage of its disulphide bridges. (+info)Mistletoe lectin dissociates into catalytic and binding subunits before translocation across the membrane to the cytoplasm. (4/66)
Hybridomas producing monoclonal antibodies (mAbs) against the mistletoe lectin A-chain (MLA) were obtained to investigate the intracellular routing and translocation of ribosome-inactivating proteins. Anti-MLA mAb MNA5 did not bind the holotoxin but interacted with isolated MLA. This epitope was not recognized upon MLA denaturation or conjugation of MLA with the ricin binding subunit (RTB). Furthermore, the mAbs did not appreciably react with a panel of MLA synthetic octapeptides linked to the surface of polyethylene pins. A study of the cytotoxicity of mistletoe lectin, ricin, and chimeric toxin MLA/RTB for the hybridomas revealed that interchain disulfide bond reduction and subunit dissociation are required for cytotoxic activity of mistletoe lectin. (+info)Cloning of the mistletoe lectin gene and characterization of the recombinant A-chain. (5/66)
Mistletoe lectin I (MLI) is the major active constituent of mistletoe extracts, which are widely used for adjuvant tumour therapy. The 66-kDa heterodimeric disulphide-linked glycoprotein is classified as type II ribosome-inactivating protein (RIP) due to the rRNA-cleaving enzyme activity of the A-subunit, also referred to as toxic entity. MLI and the close relative ricin both belong to the family of the two-chain plant type II RIP proteins. Isolation of the glycosylated proteins from plant material yield inhomogeneous material probably due to post-translational modifications. The aim of this study was to prepare pure and homogeneous protein as a prerequisite for structural and mechanistic studies in order to gain insight into the mode of action of this cytotoxic plant protein on tumour and immune cells. Of particular interest was to explain whether the differences in toxicity of ML and ricin are the result of variations of their enzymatic activities. By investigating the sequence homologies between the active sites of different RIPs we were able to deduce a set of primers which were suitable for specific amplification of the mistletoe lectin gene. Applying this PCR strategy the full-length 1923 nucleotide DNA sequence coding for the prepro-protein was obtained showing the existence of a single intron-free gene. In order to elucidate the molecular basis for the observed differences in cytotoxicity within the family of RIP the enzymatic A-subunit was expressed in a heterologous system. Expression of the A-chain in E. coli BL21/pT7 resulted in production of insoluble inclusion bodies constituting 20-30% of total protein. Refolding led to a pure and homogeneous protein species with an apparent molecular mass of 27 kDa and a pI value of 6.4. The ribosome-inactivating activity of the unglycosylated recombinant A-chain (IC50 20.5 pM) protein was in the same range as that of the glycosylated plant-derived ML A-chain (IC50 3.7 pM), which was very similar to that of ricin A-chain (IC50 4.9 pM). Thus, the higher cytotoxicity of ricin cannot be accountable for differences in the enzymatic activities of the type II RIP A-chains. (+info)Characterization of recombinant and plant-derived mistletoe lectin and their B-chains. (6/66)
Mistletoe lectin I (pML) and its isoforms ML II and III constitute the active principle in extract preparations from mistletoe, commonly used as immunomodulator in adjuvant tumour therapy. The heterodimeric disulfide-linked cytotoxic protein is classified as type II ribosome inactivating protein (RIP). Recently, the sequence coding for the mistletoe lectin prepro-protein was identified and the existence of a single intron-free gene was shown [Eck, J., Langer, M., Mockel, B., Baur, A., Rothe, M., Zinke, H. & Lentzen, H. (1999) Eur. J. Biochem. 264, 775-784]. The aim of this study was to prepare pure and homogeneous rMLB-chain as well as rML heterodimer for studying the carbohydrate binding specificity of recombinant versus natural protein and its contribution to the observed cytotoxic effect. Expression in E. coli resulted in the production of insoluble protein (inclusion bodies). A procedure for generating correctly folded, biochemically and biologically active rMLB was established starting from the insoluble single chain. Carbohydrate binding and specificity of pMLB and rMLB were analysed by a competitive enzyme linked lectin assay (ELLA). Asialofetuin was able to compete with binding of both chains (50% at 0.8 microM). The specificity of the B-chains to lactose was more distinct with halfmaximal competition at 4.9 mM (pMLB) and > 90 mM (rMLB), respectively. Furthermore, in a coassociation process rMLA- and rMLB inclusion bodies were associated in one step by defined dilution yielding active rML-heterodimer. The activities of recombinant (rML) and plant derived mistletoe lectin (pML) were compared. Cytotoxicity was determined using MOLT-4 cells and enzymatic rRNA N-glycosidase activity was measured in a coupled transcription/translation assay. The IC50 values of the two heterodimers were similar in both assays; rMLB-chain did not show any cytotoxic effect. In the ELLA with lactose as a competitor 50% competition of binding to asialofetuin was achieved at 1.6 mM (rML) and 1.8 mM (pML). Hence, using three different assays we found no significant differences between the recombinant protein and the glycosylated form of ML. Comparing the biological activities of the single chains with those of the heterodimer we conclude, that both, lectin activity and the rRNA N-glycosidase activity, are prerequisites for the cytotoxic effects on target cells. (+info)Mistletoe lectin A-chain unfolds during the intracellular transport. (7/66)
Protein conformation during intracellular routing and translocation of the ribosome-inactivating proteins was investigated on hybridomas producing monoclonal antibodies (monAbs) against mistletoe lectin (ML). Decrease in the toxin activity towards these hybridomas is accounted for by the intracellular interaction of monAbs and the toxin resulting in the interruption of enzymatic subunit translocation into the cytosol. Obtained monAbs interacted with denatured ML A-chain (MLA) and a panel of MLA synthetic octapeptides linked to the surface of polyethylene pins. Enzyme-linked immunosorbent assay (ELISA) shows that monAbs recognize five epitopes in denatured MLA. Treatment of MLA by 3 M of guanidine hydrochloride leads to appearance of the epitopes. Hybridoma TA7 has been shown to be insensitive to cytotoxic action of ML. TA7 monAb as we have shown recognizes epitope 101-105, FTGTT, and inhibits the liposome aggregation induced by MLA. A study of the cytotoxicity of ML and ricin for the hybridomas revealed that the unfolding of A-chain is probably required for intracellular transport and cytotoxic activity of ML. (+info)NMR structural determination of viscotoxin A3 from Viscum album L. (8/66)
The high-resolution three-dimensional structure of the plant toxin viscotoxin A3, from Viscum album L., has been determined in solution by (1)H NMR spectroscopy at pH 3.6 and 12 degrees C (the structure has been deposited in the Protein Data Bank under the id. code 1ED0). Experimentally derived restraints including 734 interproton distances from nuclear Overhauser effect measurements, 22 hydrogen bonds, 32 φ angle restraints from J coupling measurements, together with three disulphide bridge constraints were used as input in restrained molecular dynamics, followed by minimization, using DYANA and Discover. Backbone and heavy atom root-mean-square deviations were 0.47+/-0.11 A (1 A=10(-10) m) and 0.85+/-0.13 A respectively. Viscotoxin A3 consists of two alpha-helices connected by a turn and a short stretch of antiparallel beta-sheet. This fold is similar to that found in other thionins, such as crambin, hordothionin-alpha and -beta, phoratoxin A and purothionin-alpha and -beta. The difference in the observed biological activity for thionins of known structure is discussed in terms of the differences in the calculated surface potential distribution, playing an important role in their function through disruption of cell membranes. In addition, the possible role in DNA binding of the helix-turn-helix motif of viscotoxin A3 is discussed. (+info)Mistletoe, in a medical context, does not have a specific definition. However, it is worth noting that mistletoe is a parasitic plant that grows on the branches of trees and shrubs. In alternative medicine, extracts from mistletoe (Viscum album) are used in Europe to treat various conditions, including cancer. The extracts are thought to stimulate the immune system and have anti-tumor properties. However, it's important to note that the use of mistletoe as a medical treatment is considered complementary and alternative medicine (CAM), and its effectiveness and safety are still being studied. It should not be used as a substitute for conventional cancer treatments.
"Viscum album" is the medical term for mistletoe, a parasitic plant that grows on the branches of trees. In complementary and alternative medicine, extracts from Viscum album are used in the treatment of various medical conditions, particularly cancer. The plant contains various biologically active substances, such as lectins, viscotoxins, and polysaccharides, which are believed to have immunomodulatory, antiproliferative, and cytotoxic effects. However, it's important to note that the use of mistletoe extracts as a treatment for cancer is not supported by strong scientific evidence and its effectiveness remains controversial.
Biological toxins are poisonous substances that are produced by living organisms such as bacteria, plants, and animals. They can cause harm to humans, animals, or the environment. Biological toxins can be classified into different categories based on their mode of action, such as neurotoxins (affecting the nervous system), cytotoxins (damaging cells), and enterotoxins (causing intestinal damage).
Examples of biological toxins include botulinum toxin produced by Clostridium botulinum bacteria, tetanus toxin produced by Clostridium tetani bacteria, ricin toxin from the castor bean plant, and saxitoxin produced by certain types of marine algae.
Biological toxins can cause a range of symptoms depending on the type and amount of toxin ingested or exposed to, as well as the route of exposure (e.g., inhalation, ingestion, skin contact). They can cause illnesses ranging from mild to severe, and some can be fatal if not treated promptly and effectively.
Prevention and control measures for biological toxins include good hygiene practices, vaccination against certain toxin-producing bacteria, avoidance of contaminated food or water sources, and personal protective equipment (PPE) when handling or working with potential sources of toxins.
"Plant preparations" is not a term with a specific medical definition in the field of medicine or pharmacology. However, it is commonly used to refer to various forms of plant material that have been prepared for medicinal use. This can include dried and powdered plant parts, such as leaves, roots, or flowers, as well as extracts or concentrates made from plants. These preparations may be used in traditional medicine or as the basis for modern pharmaceuticals. It is important to note that the safety, effectiveness, and quality of plant preparations can vary widely, and they should only be used under the guidance of a qualified healthcare provider.
I apologize for any confusion, but "Loranthaceae" is not a medical term. It is a botanical term that refers to a family of flowering plants known as the mistletoes. These parasitic plants attach themselves to the branches of trees and shrubs, penetrating the bark to draw nutrients from the host plant. They have adapted to a parasitic lifestyle through evolution, losing their roots and some leaves.
If you have any questions related to medical terminology or health science, I would be happy to help!
"Viscum" is the generic name for mistletoe, a parasitic plant that grows on the branches of trees. It is used in complementary and alternative medicine, particularly in Europe. The most widely used species are Viscum album (European mistletoe) and Phoradendron serotinum (American mistletoe).
In a medical context, "Viscum" refers to the extracts of the mistletoe plant that are used in various forms of therapy. These extracts contain various biologically active compounds such as lectins, viscotoxins, and polysaccharides, which are believed to have immunomodulatory, antiproliferative, and cytotoxic effects.
Mistletoe extracts are used primarily in the treatment of cancer, with the goal of improving quality of life, reducing side effects of conventional therapies, and potentially enhancing the effectiveness of chemotherapy and radiation therapy. However, it's important to note that the scientific evidence supporting these claims is limited, and mistletoe therapy should only be administered under the guidance of a qualified healthcare professional.
Plant lectins are proteins or glycoproteins that are abundantly found in various plant parts such as seeds, leaves, stems, and roots. They have the ability to bind specifically to carbohydrate structures present on cell membranes, known as glycoconjugates. This binding property of lectins is reversible and non-catalytic, meaning it does not involve any enzymatic activity.
Lectins play several roles in plants, including defense against predators, pathogens, and herbivores. They can agglutinate red blood cells, stimulate the immune system, and have been implicated in various biological processes such as cell growth, differentiation, and apoptosis (programmed cell death). Some lectins also exhibit mitogenic activity, which means they can stimulate the proliferation of certain types of cells.
In the medical field, plant lectins have gained attention due to their potential therapeutic applications. For instance, some lectins have been shown to possess anti-cancer properties and are being investigated as potential cancer treatments. However, it is important to note that some lectins can be toxic or allergenic to humans and animals, so they must be used with caution.
I'm sorry for any confusion, but "Viscaceae" is not a medical term. It is a botanical term that refers to a family of plants commonly known as mistletoes. These are parasitic plants that grow on the branches of trees and shrinks, extracting water and nutrients from them. They have been used in traditional medicine in various cultures, but it's important to note that the use of such substances should be under the guidance of a healthcare professional due to potential side effects and interactions with other medications.
I am not aware of a specific medical definition for "Nerium." However, Nerium is a genus of plants in the dogwood family, and its most common species is Nerium oleander, also known as oleander. Oleander is a toxic plant that can cause serious health problems if ingested or touched. Its symptoms include nausea, vomiting, seizures, irregular heartbeat, and even death in severe cases. It's essential to keep oleander away from children, pets, and livestock and seek immediate medical attention if any part of the plant is accidentally ingested.
Medicinal plants are defined as those plants that contain naturally occurring chemical compounds which can be used for therapeutic purposes, either directly or indirectly. These plants have been used for centuries in various traditional systems of medicine, such as Ayurveda, Chinese medicine, and Native American medicine, to prevent or treat various health conditions.
Medicinal plants contain a wide variety of bioactive compounds, including alkaloids, flavonoids, tannins, terpenes, and saponins, among others. These compounds have been found to possess various pharmacological properties, such as anti-inflammatory, analgesic, antimicrobial, antioxidant, and anticancer activities.
Medicinal plants can be used in various forms, including whole plant material, extracts, essential oils, and isolated compounds. They can be administered through different routes, such as oral, topical, or respiratory, depending on the desired therapeutic effect.
It is important to note that while medicinal plants have been used safely and effectively for centuries, they should be used with caution and under the guidance of a healthcare professional. Some medicinal plants can interact with prescription medications or have adverse effects if used inappropriately.
"Plant proteins" refer to the proteins that are derived from plant sources. These can include proteins from legumes such as beans, lentils, and peas, as well as proteins from grains like wheat, rice, and corn. Other sources of plant proteins include nuts, seeds, and vegetables.
Plant proteins are made up of individual amino acids, which are the building blocks of protein. While animal-based proteins typically contain all of the essential amino acids that the body needs to function properly, many plant-based proteins may be lacking in one or more of these essential amino acids. However, by consuming a variety of plant-based foods throughout the day, it is possible to get all of the essential amino acids that the body needs from plant sources alone.
Plant proteins are often lower in calories and saturated fat than animal proteins, making them a popular choice for those following a vegetarian or vegan diet, as well as those looking to maintain a healthy weight or reduce their risk of chronic diseases such as heart disease and cancer. Additionally, plant proteins have been shown to have a number of health benefits, including improving gut health, reducing inflammation, and supporting muscle growth and repair.
Phytotherapy is the use of extracts of natural origin, especially plants or plant parts, for therapeutic purposes. It is also known as herbal medicine and is a traditional practice in many cultures. The active compounds in these plant extracts are believed to have various medicinal properties, such as anti-inflammatory, analgesic, or sedative effects. Practitioners of phytotherapy may use the whole plant, dried parts, or concentrated extracts to prepare teas, capsules, tinctures, or ointments for therapeutic use. It is important to note that the effectiveness and safety of phytotherapy are not always supported by scientific evidence, and it should be used with caution and preferably under the guidance of a healthcare professional.
"Abies" is a genus of evergreen trees that are commonly known as firs. They belong to the family Pinaceae and are native to the northern hemisphere, primarily in North America, Europe, and Asia. These trees are characterized by their needle-like leaves, which are flat and shiny, and their conical-shaped crowns.
Firs have been used for various purposes throughout history, including timber production, Christmas tree farming, and ornamental landscaping. Some species of firs also have medicinal properties, such as the use of Abies balsamea (balsam fir) in traditional medicine to treat respiratory ailments and skin conditions. However, it's important to note that the medical use of firs should be done under the guidance of a healthcare professional, as improper use can lead to adverse effects.
A plant extract is a preparation containing chemical constituents that have been extracted from a plant using a solvent. The resulting extract may contain a single compound or a mixture of several compounds, depending on the extraction process and the specific plant material used. These extracts are often used in various industries including pharmaceuticals, nutraceuticals, cosmetics, and food and beverage, due to their potential therapeutic or beneficial properties. The composition of plant extracts can vary widely, and it is important to ensure their quality, safety, and efficacy before use in any application.
Ricin is defined as a highly toxic protein that is derived from the seeds of the castor oil plant (Ricinus communis). It can be produced as a white, powdery substance or a mistable aerosol. Ricin works by getting inside cells and preventing them from making the proteins they need. Without protein, cells die. Eventually, this can cause organ failure and death.
It is not easily inhaled or absorbed through the skin, but if ingested or injected, it can be lethal in very small amounts. There is no antidote for ricin poisoning - treatment consists of supportive care. Ricin has been used as a bioterrorism agent in the past and continues to be a concern due to its relative ease of production and potential high toxicity.
Lectins are a type of proteins that bind specifically to carbohydrates and have been found in various plant and animal sources. They play important roles in biological recognition events, such as cell-cell adhesion, and can also be involved in the immune response. Some lectins can agglutinate certain types of cells or precipitate glycoproteins, while others may have a more direct effect on cellular processes. In some cases, lectins from plants can cause adverse effects in humans if ingested, such as digestive discomfort or allergic reactions.
"Pinus sylvestris" is the scientific name for a species of tree, not a medical term. It is commonly known as the Scotch Pine or Scots Pine and is native to Eurasia, ranging from Western Europe to Eastern Siberia. The tree can also be found in other parts of the world as an introduced species.
Here's some information about Pinus sylvestris that you might find interesting:
* Pinus sylvestris is a coniferous evergreen tree that typically grows to a height of 30-40 meters (98-131 feet) but can reach up to 60 meters (197 feet) in some cases.
* The bark of the tree is thick, scaly, and orange-reddish in color, while the leaves are needle-shaped, green, and grow in clusters of two.
* Pinus sylvestris produces both male and female cones, with the male cones releasing pollen and the female cones producing seeds.
* The tree is an important source of timber and is commonly used for construction, pulp and paper production, and as a Christmas tree.
* Pinus sylvestris has several medicinal uses, including as a treatment for respiratory conditions such as bronchitis and asthma, as well as for skin conditions like eczema and psoriasis. The needles and bark of the tree contain compounds with anti-inflammatory, antimicrobial, and antioxidant properties that are believed to be responsible for these therapeutic effects.
"Pseudotsuga" is not a medical term. It is a genus of coniferous trees in the family Pinaceae, commonly known as Douglas firs or Douglas trees. They are native to western North America and eastern Asia. The most widely known species is Pseudotsuga menziesii, which is often simply called the Douglas fir. These trees have important economic value for timber and pulp production.
Fetuins are a group of proteins that are produced by the liver and found in circulation in the blood. The most well-known fetuin, fetuin-A, is a 64 kDa glycoprotein that is synthesized in the liver and secreted into the bloodstream. Fetuin-A plays a role in several physiological processes, including inhibition of tissue calcification, regulation of insulin sensitivity, and modulation of immune responses.
Fetuin-B is another member of the fetuin family that shares some structural similarities with fetuin-A but has distinct functions. Fetuin-B is also produced by the liver and secreted into the bloodstream, where it plays a role in regulating lipid metabolism and insulin sensitivity.
It's worth noting that while both fetuins have been studied for their roles in various physiological processes, there is still much to be learned about their functions and regulation.
'Citrus sinensis' is the scientific name for the fruit species more commonly known as sweet oranges. These are popular fruits that belong to the Rutaceae family and have originated in Southeast Asia. Sweet oranges are widely cultivated and consumed all over the world, both fresh and as juice. They have a sweet taste and juicy pulp, enclosed in a thick and fragrant orange-colored peel. Some well-known varieties of 'Citrus sinensis' include Navel, Valencia, and Blood oranges.