Thalictrum
Ranunculaceae
Genes, Chloroplast
Glycosides
Purification and characterization of norcoclaurine synthase. The first committed enzyme in benzylisoquinoline alkaloid biosynthesis in plants. (1/14)
Norcoclaurine synthase (NCS; EC ) catalyzes the condensation of dopamine and 4-hydroxyphenylacetaldehyde (4-HPAA) as the first committed step in benzylisoquinoline alkaloid biosynthesis in plants. NCS was purified 1590-fold to homogeneity from cell suspension cultures of meadow rue (Thalictrum flavum ssp. glaucum). The purification procedure, which resulted in a 4.2% yield, involved hydrophobic interaction, anion exchange, hydroxyapatite, and gel filtration chromatography. Purified NCS displayed native and denatured molecular masses of approximately 28 and 15 kDa, respectively, suggesting that the enzyme is composed of two subunits. Two-dimensional polyacrylamide gel electrophoresis revealed two major and two minor isoforms with pI values between 5.5 and 6.2. NCS activity was maximal at pH 6.5 to 7.0 and temperatures between 42 and 55 degrees C and was not affected by divalent cations. The enzyme showed hyperbolic saturation kinetics for 4-HPAA (K(m) = 335 microm) but sigmoidal saturation kinetics for dopamine (Hill coefficient = 1.8) suggesting cooperativity between the dopamine binding sites on each subunit; thus, NCS might play a regulatory, or rate-limiting, role in controlling the rate of pathway flux in benzylisoquinoline alkaloid biosynthesis. Product inhibition kinetics performed at saturating levels of one substrate and with norlaudanosoline as the inhibitor showed that NCS follows an iso-ordered bi-uni mechanism with 4-HPAA binding before dopamine. NCS activity was highest in soluble protein extracts from roots followed by stems, leaves, and flower buds. (+info)Cell type-specific localization of transcripts encoding nine consecutive enzymes involved in protoberberine alkaloid biosynthesis. (2/14)
Molecular clones encoding nine consecutive biosynthetic enzymes that catalyze the conversion of l-dopa to the protoberberine alkaloid (S)-canadine were isolated from meadow rue (Thalictrum flavum ssp glaucum). The predicted proteins showed extensive sequence identity with corresponding enzymes involved in the biosynthesis of related benzylisoquinoline alkaloids in other species, such as opium poppy (Papaver somniferum). RNA gel blot hybridization analysis showed that gene transcripts for each enzyme were most abundant in rhizomes but were also detected at lower levels in roots and other organs. In situ RNA hybridization analysis revealed the cell type-specific expression of protoberberine alkaloid biosynthetic genes in roots and rhizomes. In roots, gene transcripts for all nine enzymes were localized to immature endodermis, pericycle, and, in some cases, adjacent cortical cells. In rhizomes, gene transcripts encoding all nine enzymes were restricted to the protoderm of leaf primordia. The localization of biosynthetic gene transcripts was in contrast with the tissue-specific accumulation of protoberberine alkaloids. In roots, protoberberine alkaloids were restricted to mature endodermal cells upon the initiation of secondary growth and were distributed throughout the pith and cortex in rhizomes. Thus, the cell type-specific localization of protoberberine alkaloid biosynthesis and accumulation are temporally and spatially separated in T. flavum roots and rhizomes, respectively. Despite the close phylogeny between corresponding biosynthetic enzymes, distinct and different cell types are involved in the biosynthesis and accumulation of benzylisoquinoline alkaloids in T. flavum and P. somniferum. Our results suggest that the evolution of alkaloid metabolism involves not only the recruitment of new biosynthetic enzymes, but also the migration of established pathways between cell types. (+info)Four new cycloartane glycosides from Thalictrum fortunei. (3/14)
Four new cycloartane glycosides were isolated from the aerial parts of Thalictrum fortunei (Ranunculaceae). The chemical structures of these new glycosides were elucidated as 3-O-beta-D-glucopyranosyl-(1-->4)-beta-D-fucopyranosyl (22S,24Z)-cycloart-24-en-3beta,22,26-triol 26-O-beta-D-glucopyranoside, 3-O-beta-D-glucopyranosyl-(1-->4)-beta-D-fucopyranosyl (22S,24Z)-cycloart-24-en-3beta,22,26-triol 26-O-beta-D-quinovopyranosyl-(1-->6)-beta-D-glucopyranoside, 3-O-beta-D-glucopyranosyl-(1-->4)-beta-D-fucopyranosyl (22S,24Z)-cycloart-24-en-3beta,22,26-triol 26-O-beta-D-xylopyranosyl-(1-->6)-beta-D-glucopyranoside, and 3-O-beta-D-glucopyranosyl-(1-->4)-beta-D-fucopyranosyl (22S,24Z)-cycloart-24-en-3beta,22,26-triol 26-O-alpha-L-arabinopyranosyl-(1-->6)-beta-D-glucopyranoside by extensive NMR methods, HR-ESI-MS, and hydrolysis. This is the first report of (22S,24Z)-3beta,22,26-trihydroxycycloartan-24-ene (thelictogenin A, 5) being glycosylated at C-26. (+info)Cloning, expression, crystallization and preliminary X-ray data analysis of norcoclaurine synthase from Thalictrum flavum. (4/14)
(+info)Purification, crystallization and X-ray diffraction analysis of pavine N-methyltransferase from Thalictrum flavum. (5/14)
(+info)Structural basis of enzymatic (S)-norcoclaurine biosynthesis. (6/14)
(+info)Virus-induced gene silencing as a tool for comparative functional studies in Thalictrum. (7/14)
(+info)Isoquinolines from the roots of Thalictrum flavum L. and their evaluation as antiparasitic compounds. (8/14)
(+info)I'm sorry for any confusion, but "Thalictrum" is not a medical term. It is the name of a genus of flowering plants in the family Ranunculaceae, also known as meadow rue. These plants are native to temperate regions of the Northern Hemisphere and have diverse ornamental uses due to their showy flowers. If you have any questions about a medical condition or term, I'd be happy to try to help with that instead!
Ranunculaceae is a family of flowering plants, also known as the buttercup family. It includes over 2,000 species distributed across 58 genera. The plants in this family are characterized by their showy, often brightly colored flowers and typically have numerous stamens and carpels. Many members of Ranunculaceae contain toxic compounds, which can be irritants or even poisonous if ingested. Examples of plants in this family include buttercups, delphiniums, monkshood, and columbines.
Chloroplast genes refer to the genetic material present within chloroplasts, which are specialized organelles in plant and algal cells that conduct photosynthesis. Chloroplasts have their own DNA, separate from the nuclear DNA of the cell, and can replicate independently. The chloroplast genome is relatively small and contains codes for some of the essential proteins required for photosynthesis and chloroplast function.
The chloroplast genome typically includes genes for components of the photosystems, such as Psa and Psb genes that encode for subunits of Photosystem I and II respectively, as well as genes for the large and small ribosomal RNAs (rRNA) and transfer RNAs (tRNA) required for protein synthesis within the chloroplast. However, many chloroplast proteins are actually encoded by nuclear genes and are imported into the chloroplast after their synthesis in the cytoplasm.
It is believed that chloroplasts originated from ancient photosynthetic bacteria through endosymbiosis, where the bacterial cells were engulfed by a eukaryotic cell and eventually became permanent organelles within the host cell. Over time, much of the bacterial genome was either lost or transferred to the host cell's nucleus, resulting in the modern-day chloroplast genome.
Aerial parts of plants refer to the above-ground portions of a plant, including leaves, stems, flowers, and fruits. These parts are often used in medicine, either in their entirety or as isolated extracts, to take advantage of their medicinal properties. The specific components of aerial parts that are used in medicine can vary depending on the plant species and the desired therapeutic effects. For example, the leaves of some plants may contain active compounds that have anti-inflammatory or analgesic properties, while the flowers of others may be rich in antioxidants or compounds with sedative effects. In general, aerial parts of plants are used in herbal medicine to treat a wide range of conditions, including respiratory, digestive, and nervous system disorders, as well as skin conditions and infections.
Glycosides are organic compounds that consist of a glycone (a sugar component) linked to a non-sugar component, known as an aglycone, via a glycosidic bond. They can be found in various plants, microorganisms, and some animals. Depending on the nature of the aglycone, glycosides can be classified into different types, such as anthraquinone glycosides, cardiac glycosides, and saponin glycosides.
These compounds have diverse biological activities and pharmacological effects. For instance:
* Cardiac glycosides, like digoxin and digitoxin, are used in the treatment of heart failure and certain cardiac arrhythmias due to their positive inotropic (contractility-enhancing) and negative chronotropic (heart rate-slowing) effects on the heart.
* Saponin glycosides have potent detergent properties and can cause hemolysis (rupture of red blood cells). They are used in various industries, including cosmetics and food processing, and have potential applications in drug delivery systems.
* Some glycosides, like amygdalin found in apricot kernels and bitter almonds, can release cyanide upon hydrolysis, making them potentially toxic.
It is important to note that while some glycosides have therapeutic uses, others can be harmful or even lethal if ingested or otherwise introduced into the body in large quantities.
Triterpenes are a type of natural compound that are composed of six isoprene units and have the molecular formula C30H48. They are synthesized through the mevalonate pathway in plants, fungi, and some insects, and can be found in a wide variety of natural sources, including fruits, vegetables, and medicinal plants.
Triterpenes have diverse structures and biological activities, including anti-inflammatory, antiviral, and cytotoxic effects. Some triterpenes are also used in traditional medicine, such as glycyrrhizin from licorice root and betulinic acid from the bark of birch trees.
Triterpenes can be further classified into various subgroups based on their carbon skeletons, including squalene, lanostane, dammarane, and ursane derivatives. Some triterpenes are also modified through various biochemical reactions to form saponins, steroids, and other compounds with important biological activities.