Castor Bean
Castor Oil
Ricinus
Ricinoleic Acids
Ricin
Fabaceae
Plant Lectins
Seeds
Isocitrate Lyase
2S Albumins, Plant
Plants, Medicinal
Plant Proteins
Functional characterization and expression analysis of the amino acid permease RcAAP3 from castor bean. (1/96)
A polymerase chain reaction-based library screening procedure was used to isolate RcAAP3, an amino acid permease cDNA from castor bean (Ricinus communis). RcAAP3 is 1.7 kb in length, with an open reading frame that encodes a protein with a calculated molecular mass of 51 kD. Hydropathy analysis indicates that the RcAAP3 protein is highly hydrophobic in nature with nine to 11 putative transmembrane domains. RcAAP3-mediated uptake of citrulline in a yeast transport mutant showed saturable kinetics with a K(m) of 0.4 mM. Transport was higher at acidic pH and was inhibited by the protonophore carbonylcyanide-m-chlorophenylhydrazone, suggesting a proton-coupled transport mechanism. Citrulline uptake was strongly inhibited (72%) by the permeable sulfydryl reagent N-ethylmaleimide, but showed lower sensitivity (30% inhibition) to the nonpermeable reagent p-chloromercuribenzenesulfonic acid. Diethylpyrocarbonate, a histidine modifier, inhibited citrulline uptake by 80%. A range of amino acids inhibited citrulline uptake, suggesting that RcAAP3 may be a broad substrate permease that can transport neutral and basic amino acids with a lower affinity for acidic amino acids. Northern analysis indicated that RcAAP3 is widely expressed in source and sink tissues of castor bean, and that the pattern of expression is distinct from RcAAP1 and RcAAP2. (+info)Programmed cell death in castor bean endosperm is associated with the accumulation and release of a cysteine endopeptidase from ricinosomes. (2/96)
The cells of the endosperm of castor bean seeds (Ricinus communis) undergo programmed cell death during germination, after their oil and protein reserves have been mobilized. Nuclear DNA fragmentation first was observed at day 3 in the endosperm cells immediately adjacent to the cotyledons and progressed across to the outermost cell layers by day 5. We also detected the accumulation of small organelles known as ricinosomes, by using an antibody against a cysteine endoprotease. By the time the nuclear DNA was susceptible to heavy label by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling, the ricinosomes had released into the cytoplasm their content of cysteine endoprotease, which became activated because of the cleavage of its propeptide. The cysteine endoprotease is distinguished by a C-terminal KDEL sequence, although it is not retained in the lumen of the endoplasmic reticulum and is a marker for ricinosomes. Homologous proteases are found in the senescing tissues of other plants, including the petals of the daylily. Ricinosomes were identified in this tissue by electron microscopy and immunocytochemistry. It seems that ricinosomes are not unique to Ricinus and play an important role in the degradation of plant cell contents during programmed cell death. (+info)Variation in the oxygen isotope ratio of phloem sap sucrose from castor bean. Evidence in support of the Peclet effect. (3/96)
Theory suggests that the level of enrichment of (18)O above source water in plant organic material (Delta) may provide an integrative indicator of control of water loss. However, there are still gaps in our understanding of the processes affecting Delta. One such gap is the observed discrepancy between modeled enrichment of water at the sites of evaporation within the leaf and measured enrichment of the leaf water as a whole (Delta(L)). Farquhar and Lloyd (1993) suggested that this may be caused by a Peclet effect. It is also unclear whether organic material formed in the leaf reflects enrichment of water at the sites of evaporation within the leaf or Delta(L). To investigate this question castor bean (Ricinus communis L.) leaves, still attached to the plant, were sealed into a controlled-environment gas exchange chamber and subjected to a step change in leaf-to-air vapor pressure difference. Sucrose was collected from a cut on the petiole of the leaf in the chamber under equilibrium conditions and every hour for 6 h after the change in leaf-to-air vapor pressure difference. Oxygen isotope composition of sucrose in the phloem sap (Delta(suc)) reflected modeled Delta(L). A model is presented describing Delta(suc) at isotopic steady state, and accounts for 96% of variation in measured Delta(suc). The data strongly support the Peclet effect theory. (+info)Engineering delta 9-16:0-acyl carrier protein (ACP) desaturase specificity based on combinatorial saturation mutagenesis and logical redesign of the castor delta 9-18:0-ACP desaturase. (4/96)
Six amino acid locations in the soluble castor Delta(9)-18:0-acyl carrier protein (ACP) desaturase were identified that can affect substrate specificity. Combinatorial saturation mutagenesis of these six amino acids, in conjunction with selection, using an unsaturated fatty acid auxotroph system, led to the isolation of variants with up to 15-fold increased specific activity toward 16-carbon substrates. The most improved mutant, com2, contained two substitutions (T117R/G188L) common to five of the 19 complementing variants subjected to further analysis. These changes, when engineered into otherwise wild-type 18:0-ACP desaturase to make mutant 5.2, produced a 35-fold increase in specific activity with respect to 16-carbon substrates. Kinetic analysis revealed changes in both k(cat) and K(m) that result in an 82-fold improvement in specificity factor for 16-carbon substrate compared with wild-type enzyme. Improved substrate orientation apparently compensated for loss of binding energy that results from the loss of desolvation energy for 16-carbon substrates. Mutant 5.2 had specific activity for 16-carbon substrates 2 orders of magnitude higher than those of known natural 16-carbon specific desaturases. These data support the hypothesis that it should be possible to reengineer archetypal enzymes to achieve substrate specificities characteristic of recently evolved enzymes while retaining the desired stability and/or turnover characteristics of a parental paralog. (+info)Lipolytic activity of ricin from Ricinus sanguineus and Ricinus communis on neutral lipids. (5/96)
The present study was carried out with a view of determining ricin lipolytic activity on neutral lipids in emulsion and in a membrane-like model. Using 2,3-dimercapto-1-propanol tributyrate (BAL-TC(4)) as substrate, the lipolytic activity of ricin was found to be proportional to ricin and substrate concentrations, with an apparent K(m) (K(m,app)) of 2.4 mM, a k(cat) of 200 min(-1) and a specific activity of 1.0 unit/mg of protein. This work was extended to p-nitrophenyl (pNP) fatty acid esters containing two to twelve carbon atoms. Maximum lipolytic activity was registered on pNP decanoate (pNPC(10)), with a K(m,app) of 3.5 mM, a k(cat) of 173 min(-1) and a specific activity of 3.5 units/mg of protein. Ricin lipolytic activity is pH and galactose dependent, with a maximum at pH 7.0 in the presence of 0.2 M galactose. Using the monolayer technique with dicaprin as substrate, ricin showed a lipolytic activity proportional to the ricin concentration at 20 mN/m, which is dependent on the surface pressure of the lipid monolayer and is detectable up to 30 mN/m, a surface pressure that is of the same order of magnitude as that of natural cell membranes. The methods based on pNPC(10) and BAL-TC(4) hydrolysis are simple and reproducible; thus they can be used for routine studies of ricin lipolytic activity. Ricin from Ricinus communis and R. sanguineus were treated with diethyl p-nitrophenylphosphate, an irreversible serine esterase inhibitor, and their lipolytic activities on BAL-TC(4) and pNPC(10), and cytotoxic activity, were concurrently recorded. A reduction in lipolytic activity was accompanied by a decrease in cytotoxicity on Caco2 cells. These data support the idea that the lipolytic activity associated with ricin is relevant to a lipase whose activity is pH and galactose dependent, sensitive to diethyl p-nitrophenylphosphate, and that a lipolytic step may be involved in the process of cell poisoning by ricin. Both colorimetric tests used in this study are sensitive enough to be helpful in the detection of possible lipolytic activities associated with other cytotoxins or lectins. (+info)Graviresponsiveness and the development of columella tissue in primary and lateral roots of Ricinus communis. (6/96)
Half-tipped primary and lateral roots of Ricinus communis cv Hale bend toward the side of the root on which the intact half-tip remains. Therefore, the minimal graviresponsiveness of lateral roots is not due to the inability of their caps to produce growth effectors (presumably inhibitors). The columella tissues of primary (i.e. graviresponsive) roots are (a) 4.30 times longer, (b) 2.95 times wider, (c) 37.4 times more voluminous, and (d) composed of 17.2 times more cells than those of lateral roots. The onset of positive gravitropism by lateral roots is positively correlated with a (a) 2.99-fold increase in length, (b) 2.63-fold increase in width, (c) 20.7-fold increase in volume of their columella tissues. We propose that the minimal graviresponsiveness of lateral roots is due to the small size of their columella tissues, which results in their caps being unable to (a) establish a concentration gradient of the effector sufficient to induce gravicurvature and (b) produce as much as the effector as caps of graviresponsive roots. (+info)The breakdown of lipid reserves in the endosperm of germinating castor beans. (7/96)
1. Lipid extracts were obtained from castor-bean endosperm tissue at various times during germination and, after purification, the total lipid content was determined. Quantitative measurements of the triglyceride and phospholipid content together with the fatty acid composition were made. 2. The total lipid content of the endosperm rapidly decreased during germination; after 10 days less than 20% of the original weight of lipid remained. In contrast, the phospholipid content (initially less than 0.5% of the total lipid) increased slightly during this time. The fatty acid composition and the relative proportions of the triglyceride species of the total lipid extract remained constant during 10 days of germination. 3. Gibberellic acid (0.3 mM) markedly stimulated the rate of lipid breakdown but did not alter either the fatty acid composition or the relative proportion of triglyceride species. 4. The embryo had little effect on lipid metabolism in the endosperm tissue; only after 6 days of germination were differences observed in the rate of fat utilization in the presence and absence of the embryo. (+info)Isolation of lysophosphatidic acid phosphatase from developing peanut cotyledons. (8/96)
The soluble fraction of immature peanut (Arachis hypogaea) was capable of dephosphorylating [(3)H]lysophosphatidic acid (LPA) to generate monoacylglycerol (MAG). The enzyme responsible for the generation of MAG, LPA phosphatase, has been identified in plants and purified by successive chromatography separations on octyl-Sepharose, Blue Sepharose, Superdex-75, and heparin-agarose to apparent homogeneity from developing peanuts. This enzyme was purified 5,048-fold to a final specific activity of 858 nmol min(-1) mg(-1). The enzyme has a native molecular mass of approximately 39 kD determined by gel filtration and migrates as a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a subunit molecular mass of 39 +/- 1.5 kD. The K(m) values for oleoyl-, stearoyl-, and palmitoyl-sn-glycerol-3-phosphate were determined to be 28.6, 39.3, and 47.9 microM, respectively. The LPA phosphatase was specific to LPA and did not utilize any other substrate such as glycerol-3-phosphate, phosphatidic acid, or p-nitrophenylphosphate. The enzyme activity was stimulated by the low concentrations of detergents such as Triton X-100 and octylglucoside. Cations had no effect on the enzyme activity. Fatty acids, sphingosine, and sphingomyelin at low concentrations stimulated the enzyme activity. The identification of LPA phosphatase in plants demonstrates the existence of MAG biosynthetic machinery in plants. (+info)A castor bean, also known as Ricinus communis, is a plant that produces seeds called castor beans. The seed of the castor bean contains ricin, a highly toxic protein that can cause serious illness or death if ingested, inhaled, or injected. Despite its toxicity, the oil from the castor bean, known as castor oil, is used in a variety of industrial and medicinal applications due to its unique chemical properties.
It's important to note that all parts of the castor bean plant are considered poisonous, but the seed is the most toxic. Handling or coming into contact with the plant or seeds can cause skin irritation and other adverse reactions in some people. It is recommended to handle the plant with care and keep it out of reach of children and pets.
Castor oil is a colorless or pale yellow vegetable oil that is derived from the seeds of the castor bean plant (Ricinus communis). It has a wide range of uses, including as a laxative, a moisturizer in skin and hair products, and a component in industrial lubricants and biodiesel.
Medically, castor oil is often used as a stimulant laxative to relieve constipation. It works by increasing the movement of the intestines, which helps to promote bowel movements. Castor oil is typically taken orally, and its effects usually begin to be felt within 2-6 hours after ingestion.
It's important to note that castor oil should not be used in large amounts or for prolonged periods of time, as it can lead to electrolyte imbalances and other serious side effects. It is also not recommended for use during pregnancy, as it may stimulate uterine contractions. As with any medication or supplement, it's always best to consult with a healthcare provider before using castor oil.
"Ricinus" is the botanical name for the castor oil plant. Its scientific name is "Ricinus communis." It is a species of flowering plant in the spurge family, Euphorbiaceae. The castor oil that comes from this plant is used in various industries and as a traditional medicine, although the raw seed is toxic due to its ricin content.
Ricinoleic acid is not typically defined in the context of medical terminology, but it is a chemical compound with potential medical relevance. It is a fatty acid that is the main constituent of castor oil, which is obtained from the seeds of the Ricinus communis plant. Ricinoleic acid has been studied for its potential medicinal properties, including its anti-inflammatory, analgesic, and antibacterial effects. However, it is important to note that ricinoleic acid can also cause irritation and inflammation in high concentrations or with prolonged exposure. Therefore, medical definitions of this compound typically focus on its chemical structure and properties rather than its potential medicinal uses.
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.
'Toxic plants' refer to those species of plants that contain toxic substances capable of causing harmful effects or adverse health reactions in humans and animals when ingested, touched, or inhaled. These toxins can cause a range of symptoms from mild irritation to serious conditions such as organ failure, paralysis, or even death depending on the plant, the amount consumed, and the individual's sensitivity to the toxin.
Toxic plants may contain various types of toxins, including alkaloids, glycosides, proteins, resinous substances, and essential oils. Some common examples of toxic plants include poison ivy, poison oak, nightshade, hemlock, oleander, castor bean, and foxglove. It is important to note that some parts of a plant may be toxic while others are not, and the toxicity can also vary depending on the stage of growth or environmental conditions.
If you suspect exposure to a toxic plant, it is essential to seek medical attention immediately and, if possible, bring a sample of the plant for identification.
Fabaceae is the scientific name for a family of flowering plants commonly known as the legume, pea, or bean family. This family includes a wide variety of plants that are important economically, agriculturally, and ecologically. Many members of Fabaceae have compound leaves and produce fruits that are legumes, which are long, thin pods that contain seeds. Some well-known examples of plants in this family include beans, peas, lentils, peanuts, clover, and alfalfa.
In addition to their importance as food crops, many Fabaceae species have the ability to fix nitrogen from the atmosphere into the soil through a symbiotic relationship with bacteria that live in nodules on their roots. This makes them valuable for improving soil fertility and is one reason why they are often used in crop rotation and as cover crops.
It's worth noting that Fabaceae is sometimes still referred to by its older scientific name, Leguminosae.
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.
In medical terms, "seeds" are often referred to as a small amount of a substance, such as a radioactive material or drug, that is inserted into a tissue or placed inside a capsule for the purpose of treating a medical condition. This can include procedures like brachytherapy, where seeds containing radioactive materials are used in the treatment of cancer to kill cancer cells and shrink tumors. Similarly, in some forms of drug delivery, seeds containing medication can be used to gradually release the drug into the body over an extended period of time.
It's important to note that "seeds" have different meanings and applications depending on the medical context. In other cases, "seeds" may simply refer to small particles or structures found in the body, such as those present in the eye's retina.
Isocitrate lyase is an enzyme that plays a crucial role in the glyoxylate cycle, a metabolic pathway found in plants, bacteria, fungi, and parasites. This cycle bypasses two steps of the citric acid cycle (TCA cycle) and allows these organisms to grow on two-carbon compounds as their sole carbon source.
Isocitrate lyase specifically catalyzes the conversion of isocitrate into succinate and glyoxylate, which are further processed in the glyoxylate cycle to generate oxaloacetate and other metabolic intermediates. In humans, isocitrate lyase is not typically found in healthy tissues but has been observed in certain pathological conditions such as tumor growth and during periods of nutrient deprivation. It is also involved in the biosynthesis of fatty acids and steroids in some organisms.
2S albumins are a type of protein found in plants. They are part of the larger family of storage proteins, which are abundant in seeds and provide nutrients to the developing plant embryo. 2S albumins are characterized by their small size, stable structure, and ability to resist digestion in the gut, making them important allergens in some plants.
The name "2S albumins" refers to their sedimentation coefficient, which is a measure of their size and shape in an ultracentrifuge. These proteins typically have a molecular weight of around 8-16 kDa and consist of two subunits held together by disulfide bonds. They are found in a wide variety of plant species, including legumes, cereals, and nuts.
In addition to their role as allergens, 2S albumins have been studied for their potential health benefits. Some studies suggest that they may have antimicrobial, antioxidant, and anti-inflammatory properties, although more research is needed to confirm these effects and understand their mechanisms of action.
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.
A chloroplast genome is the entire genetic material that is present in the chloroplasts, which are organelles found in plant cells and some protists. The chloroplast genome is circular in shape and contains about 120-160 kilobases (kb) of DNA. It encodes for a small number of proteins, ribosomal RNAs, and transfer RNAs that are required for the function of the chloroplasts, particularly in photosynthesis. The chloroplast genome is usually inherited maternally, meaning it is passed down from the mother to her offspring.
The chloroplast genome is relatively simple compared to the nuclear genome, which contains many more genes and regulatory elements. However, most of the proteins required for chloroplast function are actually encoded in the nucleus and imported into the chloroplasts. The study of chloroplast genomes can provide insights into the evolutionary history of plants and their photosynthetic ancestors.