RESUMO
Secondary metabolites of plants have important biological functions, which often depend on their localization in tissues. Ideally, a fresh untreated material should be directly analyzed to obtain a realistic view of the true sample chemistry. Therefore, there is a large interest for ambient mass-spectrometry-based imaging (MSI) methods. Our aim was to simplify this technology and to find an optimal combination of desorption/ionization principles for a fast ambient MSI of macroscopic plant samples. We coupled a 405 nm continuous wave (CW) ultraviolet (UV) diode laser to a three-dimensionally (3D) printed low-temperature plasma (LTP) probe. By moving the sample with a RepRap-based sampling stage, we could perform imaging of samples up to 16 × 16 cm2. We demonstrate the system performance by mapping mescaline in a San Pedro cactus ( Echinopsis pachanoi) cross section, tropane alkaloids in jimsonweed ( Datura stramonium) fruits and seeds, and nicotine in tobacco ( Nicotiana tabacum) seedlings. In all cases, the anatomical regions of enriched compound concentrations were correctly depicted. The modular design of the laser desorption (LD)-LTP MSI platform, which is mainly assembled from commercial and 3D-printed components, facilitates its adoption by other research groups. The use of the CW-UV laser for desorption enables fast imaging measurements. A complete tobacco seedling with an image size of 9.2 × 15.0 mm2 was analyzed at a pixel size of 100 × 100 µm2 (14 043 mass scans), in less than 2 h. Natural products can be measured directly from native tissues, which inspires a broad use of LD-LTP MSI in plant chemistry studies.
Assuntos
Alcaloides/análise , Cactaceae/química , Datura stramonium/química , Nicotiana/química , Nicotina/análise , Alcaloides/metabolismo , Cactaceae/metabolismo , Temperatura Baixa , Datura stramonium/metabolismo , Desenho de Equipamento , Mescalina/análise , Mescalina/metabolismo , Nicotina/metabolismo , Sementes/química , Sementes/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/instrumentação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Nicotiana/metabolismoRESUMO
We examined the effects of light conditions on plant growth and production of defense compounds in the toxic species Datura inoxia and D. stramonium. Specifically, we investigated morphological and physiological traits, including the contents of nitrogen-based tropane alkaloids (atropine and scopolamine) as defense compounds, under three light conditions: 100%, 80%, and 50% of full sunlight. Both species showed similar morphological and physiological responses to exposure to different intensities of light. Although the total plant mass decreased under lower light conditions, the total leaf area per plant increased. The reason being that the leaf mass per plant did not decrease, while the leaf mass per unit area decreased. Leaf nitrogen and chlorophyll concentrations and the chlorophyll/nitrogen ratio increased under lower light conditions, whereas the chlorophyll a/b ratio decreased. These morphological and physiological changes may be seen as ways to increase light acquisition under low light conditions. Leaf atropine and scopolamine concentrations did not differ among the three light conditions for both species. In conclusion, both Datura species underwent morphological and physiological changes under low light conditions, enabling them to use carbon and nitrogen to increase light acquisition while maintaining their chemical defense capability.
Assuntos
Datura stramonium/crescimento & desenvolvimento , Datura/crescimento & desenvolvimento , Atropina/metabolismo , Clorofila/metabolismo , Datura/metabolismo , Datura/efeitos da radiação , Datura stramonium/metabolismo , Datura stramonium/efeitos da radiação , Luz , Nitrogênio/metabolismo , Folhas de Planta/metabolismo , Escopolamina/metabolismoRESUMO
OBJECTIVE: To study the effects of methyl jasmonate (MJ) on the accumulation and release of main secondary metabolites i. e. scopolamine and hyoscyamine in liquid cultures of Datura stramonium hairy roots. METHOD: After 18 days liquid culture of D. stramonium hairy roots induced by agrobacterium rhizogenes C58C1, the chemical elicitor methyl jasmonate was added into 1/2 MS liquid cultures and scopolamine and hyoscyamine on the day 0, 3, 6, 9 and 12, after dealing with MJ, was determined by HPLC. RESULT: After dealing with MJ on the day 3, 6, 9 and 12,the concentration of scopolamine reached to 0.419, 0.439, 0.431, 0.374 mg x g(-1), respectively, the increase of scopolamine were 1.36, 1.42, 1.17 and 1.12 fold higher than that of the control, respectively. And hyoscyamine reached 1.493, 0.817, 0.723 and 0.698 mg x g(-1), respectively, the increase of hyoscyamine were 2.28, 1.11, 0.63 and 0.70 fold higher than that of the control, respectively. CONCLUSION: MJ could stimulate the accumulation of scopolamine and hyoscyamine (3,6 d) in D. stramonium hairy root and have released them into the culture medium.
Assuntos
Acetatos/farmacologia , Alcaloides/metabolismo , Ciclopentanos/farmacologia , Datura stramonium/efeitos dos fármacos , Datura stramonium/metabolismo , Oxilipinas/farmacologia , Tropanos/metabolismo , Alcaloides/análise , Técnicas de Cultura de Células , Datura stramonium/química , Datura stramonium/crescimento & desenvolvimento , Raízes de Plantas/química , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Tropanos/análiseRESUMO
Background: Inflammation is a frequent phenomenon in the pathogenesis of hepatic disorders leading to fibrosis and cirrhosis. Phytopharmaceuticals developed from traditional medicine can provide effective therapeutic alternatives to conventional medications. Datura stramonium (DS) has reported traditional uses in inflammatory diseases. In this study, we have tried to validate its potential as a source of anti-inflammatory agents. Methods: Powdered leaf part of DS was extracted using ethyl acetate (EA) to provide the extract (DSL-EA). Lymphocyte and macrophage viability and acute toxicity assays established the safety profile, while nitric oxide (NO) scavenging assay estimated the in vitro anti-inflammatory potential. Noninvasive anti-inflammatory, antidepressant, and antinociceptive activities were monitored using BALB/c mice using low and high doses (150 and 250 mg/kg). Major inflammatory studies were performed on Sprague-Dawley male rats using CCl4-induced liver injury model. Disease induction was initiated by intraperitoneal injections of CCl4 (1 mL/kg of 30% CCl4 in olive oil). The rats were divided into six groups. The anti-inflammatory potential of DSL-EA in low and high doses (150 and 300 mg/kg, respectively) was assessed through hematological, biochemical, liver antioxidant defense, oxidative stress markers, and histological studies as well as the expression of Nrf2 and iNOS. Results: DSL-EA exhibited prominent in vitro NO scavenging (IC50: 7.625 ± 0.51 µg/mL) and in vivo anti-inflammatory activity in paw and anal edema models. In CCl4 model, hematological investigations revealed vasotonic effects. Liver functionality was significantly (P < 0.001 - 0.05) improved in DSL-EA-treated rats. The activity level of endogenous antioxidant enzymes in liver tissues was improved in a manner identical to silymarin. The extract reduced the percent concentration of oxidative stress markers in liver tissues. Furthermore, DSL-EA displayed restorative effects on histological parameters (H and E and Masson's trichrome staining). Immunohistochemistry studies showed marked decline in Nrf2 expression, while overexpression of iNOS was also observed in disease control rats. The damage was distinctly reversed by the extract.
Assuntos
Doença Hepática Induzida por Substâncias e Drogas , Datura stramonium , Animais , Anti-Inflamatórios/farmacologia , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Biomarcadores/metabolismo , Tetracloreto de Carbono/toxicidade , Doença Hepática Induzida por Substâncias e Drogas/patologia , Datura stramonium/metabolismo , Fígado/patologia , Masculino , Camundongos , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo , Extratos Vegetais , Ratos , Ratos Sprague-DawleyRESUMO
Chitin binding lectin, found in seeds of Datura stramonium (DSL), is an important glycan binding protein that has great therapeutic properties. The objective of the study is to understand the evolutionary significance, structural and functional characterization of chitin binding lectin from D. stramonium, thus will facilitate to explore in deeper structural insights about the protein and its interactions with substrates. In this study, initially the sequence analysis was performed for chitin binding lectin to understand the sequential properties followed by using similarity search, multiple sequence alignment and phylogenetic analysis to identify the closely related protein sequences of DSL. After this, we utilized hybrid homology modeling-ab initio approaches to predict the 3D model of DSL, which is subsequently used for interaction studies with four ligands namely N,N'-Diacetylchitobiose, Triacetylchitotriose and Chitin tetramer, which are all oligomers of chitin. Docking analysis was also performed for N-Acetyllactosamine, which is reported as a potent inhibitor of haemagglutination by Datura lectin. Interestingly we observed two binding sites of substrate. The active site residues in predicted binding site are Glu272, Arg62 and Thr246. Moreover, the best four DSL-ligand complexes along with unbounded form of DSL were subjected to MD simulation to understand the structural stability, integrity and compactness. Together the results of docking and MD simulation, the chitotriose oriented in center of the DSL showing more binding affinity towards binding pocket of DSL. This comprehensive analysis of DSL provides key insights about the structure, active site, binding affinity and mode of binding of the substrates.Communicated by Ramaswamy H. Sarma.
Assuntos
Datura stramonium , Lectinas , Quitina , Datura stramonium/metabolismo , Lectinas/genética , Lectinas/metabolismo , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Filogenia , Lectinas de Plantas/genética , Ligação ProteicaRESUMO
Tropane alkaloids and terpenoids are widely used in the medicine and pharmaceutic industry and evolved as chemical defenses against herbivores and pathogens in the annual herb Datura stramonium (Solanaceae). Here, we present the first draft genomes of two plants from contrasting environments of D. stramonium. Using these de novo assemblies, along with other previously published genomes from 11 Solanaceae species, we carried out comparative genomic analyses to provide insights on the genome evolution of D. stramonium within the Solanaceae family, and to elucidate adaptive genomic signatures to biotic and abiotic stresses in this plant. We also studied, in detail, the evolution of four genes of D. stramonium-Putrescine N-methyltransferase, Tropinone reductase I, Tropinone reductase II and Hyoscyamine-6S-dioxygenase-involved in the tropane alkaloid biosynthesis. Our analyses revealed that the genomes of D. stramonium show signatures of expansion, physicochemical divergence and/or positive selection on proteins related to the production of tropane alkaloids, terpenoids, and glycoalkaloids as well as on R defensive genes and other important proteins related with biotic and abiotic pressures such as defense against natural enemies and drought.
Assuntos
Datura stramonium/genética , Datura stramonium/metabolismo , Defesa das Plantas contra Herbivoria/genética , Oxirredutases do Álcool/metabolismo , Alcaloides/metabolismo , Evolução Biológica , Meio Ambiente , Evolução Molecular , Interação Gene-Ambiente , Genômica/métodos , Solanaceae/genética , Solanaceae/metabolismo , Tropanos/metabolismo , Sequenciamento Completo do GenomaRESUMO
Traditionally, optimization in biological analyses has been carried out by monitoring the influence of one factor at a time; this technique is called one-variable-at-a-time. The disadvantage of this technique is that it does not include any interactive effects among the variables studied and requires a large number of experiments. Therefore, in recent years, the Response Surface Methodology (RSM) has become the most popular optimization method. It is an effective mathematical and statistical technique which has been widely used in optimization studies with minimal experimental trials where interactive factors may be involved. This present study follows on from our previous work, where RSM was used to optimize the B5 medium composition in [NO(3-)], [Ca(2+)] and sucrose to attain the best production of hyoscyamine (HS) from the hairy roots (HRs) of Datura stramonium elicited by Jasmonic Acid (JA). The present paper focuses on the use of the RSM in biological studies, such as plant material, to establish a predictive model with the planning of experiments, analysis of the model, diagnostics and adjustment for the accuracy of the model. With the RSM, only 20 experiments were necessary to determine optimal concentrations. The model could be employed to carry out interpolations and predict the response to elicitation. Applying this model, the optimization of the HS level was 212.7% for the elicited HRs of Datura stramonium, cultured in B5-OP medium (optimized), in comparison with elicited HRs cultured in B5 medium (control). The optimal concentrations, under experimental conditions, were determined to be: 79.1 mM [NO(3-)], 11.4 mM [Ca(2+)] and 42.9 mg/L of sucrose.
Assuntos
Biotecnologia/métodos , Meios de Cultura/química , Datura stramonium/metabolismo , Hiosciamina/biossíntese , Modelos Estatísticos , Raízes de Plantas/metabolismo , Cálcio/análise , Técnicas de Química Analítica/métodos , Datura stramonium/química , Datura stramonium/crescimento & desenvolvimento , Nitratos/análise , Raízes de Plantas/crescimento & desenvolvimento , Sacarose/análiseRESUMO
The effect of kappa/beta-carrageenan from red alda Tichocarpus crinitus on the development of a potato virus X (PVX) infection in the leaves of Datura stramonium L. has been studied. The treatment of leaves with carrageenan stimulates a protein synthesis in the cells, causing an increase in the size of nucleoli and in the number of mitochondria and membranes of the granular endoplasmic reticulum. At the same time, such treatment slightly stimulates lytic processes, causing an increase in the number of agranular endoplasmic reticulum cisterns, dictyosomes, and cytoplasmic vacuoles and the formation of cytoplasmic zones, transparent to electron microscopy. The carrageenan-induced stimulation of lytic processes results in the destruction of viral particles and can be considered as one of the defense mechanisms, preventing the intracellular accumulation of viruses. The carrageenan-stimulated formation of PVX-specific laminar structures, able to bind viral particles and, therefore, prevent their intracellular translocation and reproduction, represents another carrageenan-induced mechanism of the antiviral defense in plant cells.
Assuntos
Carragenina/farmacologia , Datura stramonium/virologia , Doenças das Plantas/virologia , Folhas de Planta/virologia , Potexvirus/metabolismo , Rodófitas/química , Carragenina/química , Datura stramonium/metabolismo , Datura stramonium/ultraestrutura , Folhas de Planta/metabolismo , Folhas de Planta/ultraestrutura , Potexvirus/ultraestruturaRESUMO
Datura stramonium seeds contain at least three chitin-binding isolectins as homo- or heterodimers of A and B subunits. This lectin has been used for the detection and isolation of sugar chains with N-acetyllactosaminyl structures on highly branched N-glycans. In terms of future diagnostic use, the development of a recombinant lectin will be the most effective approach for producing homogeneous lectin preparations. This chapter presents details of the procedure used for lectin purification and also describes a method that can be used for producing active recombinant homodimeric BB-isolectin in Arabidopsis plants.
Assuntos
Aglutininas/genética , Aglutininas/isolamento & purificação , Datura stramonium/metabolismo , Datura stramonium/genética , Proteínas de Plantas/genética , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/metabolismo , Engenharia de Proteínas , Multimerização Proteica , Proteínas Recombinantes/metabolismo , Sementes/genética , Sementes/metabolismoRESUMO
Globalization facilitated the spread of invasive alien species (IAS), undermining the stability of the world's ecosystems. We investigated the metabolomic profiles of three IAS species: Chromolaena odorata (Asteraceae) Datura stramonium (Solanaceae), and Xanthium strumarium (Asteraceae), comparing metabolites of individual plants in their native habitats (USA), to their invasive counterparts growing in and around Kruger National Park (South Africa, ZA). Metabolomic samples were collected using RApid Metabolome Extraction and Storage (RAMES) technology, which immobilizes phytochemicals on glass fiber disks, reducing compound degradation, allowing long-term, storage and simplifying biochemical analysis. Metabolomic differences were analyzed using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) of samples eluted from RAMES disks. Partial Least Squares-Discriminant Analysis (PLS-DA) of metabolomes of individual plants allowed statistical separation of species, native and invasive populations of each species, and some populations on the same continent. Invasive populations of all species were more phytochemically diverse than their native counterparts, and their metabolomic profiles were statistically distinguishable from their native relatives. These data may elucidate the mechanisms of successful invasion and rapid adaptive evolution of IAS. Moreover, RAMES technology combined with PLS-DA statistical analysis may allow taxonomic identification of species and, possibly, populations within each species.
Assuntos
Chromolaena/metabolismo , Datura stramonium/metabolismo , Espécies Introduzidas/tendências , Xanthium/metabolismo , Cromatografia Líquida/métodos , Chromolaena/genética , Datura stramonium/genética , Análise Discriminante , Ecossistema , Metaboloma/genética , Metabolômica/métodos , África do Sul , Especificidade da Espécie , Espectrometria de Massas em Tandem/métodos , Xanthium/genéticaRESUMO
This study pioneered an approach that determined the effects of excess manganese (Mn) on three species; Datura stramonium, Alhagi camelthorn and Chenopodium ambrosioides. We investigated their levels of Mn, antioxidative enzymes and oxidative damage biomarkers in plants (zone 1) in and outside (zone 2) the Mn mine. The results showed that total and available Mn were at toxic levels for plants growing on zone 1. The Mn levels in each plant species were higher in leaves, stems and roots. Mn was only accumulated significantly in leaf vacuoles of A. camelthorn. Antioxidative enzyme activities of C. ambrosioides and/or D. stramonium in zone 1 were higher in leaves, stems and then in their roots. Malondialdehyde (MDA) and dityrosine levels were insignificantly higher in tissues of the studied plants in zone 1 with respect to zone 2. The roots of studied plants showed significantly higher levels of these biomarkers in comparison with their leaves in zone 1. Accordingly, antioxidative enzymatic response to Mn-stress in D. stramonium and C. ambrosioides and possibly accumulation of Mn in leaf vacuoles of A. camelthorn, protected them from oxidative damages and involved in their tolerance in Mn mine.
Assuntos
Manganês/toxicidade , Plantas/efeitos dos fármacos , Poluentes do Solo/toxicidade , Adaptação Fisiológica , Biomarcadores/metabolismo , Chenopodium ambrosioides/efeitos dos fármacos , Chenopodium ambrosioides/metabolismo , Datura stramonium/efeitos dos fármacos , Datura stramonium/metabolismo , Fabaceae/efeitos dos fármacos , Fabaceae/metabolismo , Malondialdeído/metabolismo , Manganês/análise , Manganês/metabolismo , Mineração , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Plantas/metabolismo , Poluentes do Solo/análise , Poluentes do Solo/metabolismo , Vacúolos/metabolismoRESUMO
AIM: To investigate the production of p-hydroxymethylphenol-beta-D-glucoside (gastrodin) through biotransformation by plant cell suspension cultures. METHODS: Using cell suspension cultures of Datura stramonium to convert the exogenous p-hydroxybenzaldehyde into gastrodin was conducted and the converted compounds were separated with a combination of multi-chromatography. Their chemical structures were determined on the basis of spectral analysis and chemical evidence. RESULTS: The conversion procedure of p-hydroxybenzaldehyde into gastrodin by Datura stramonium cell suspension cultures was established. The synthesized gastrodin (II) was isolated from the fermental liquor and identified by spectral analysis. At the same time, the p-hydroxybenzyl alcohol (I) converted through biotransformation of p-hydroxybenzaldehyde by cell suspension cultures of Datura stramonium was also isolated and identified. Two compounds were also isolated from the cell cultures and they were identified as beta-D-furanoallulose (III) and n-butyloxystyryl-beta-D-pyranoallulose (IV). CONCLUSION: Datura stramonium grown in suspension cultures can convert exogenous p-hydroxybenzaldehyde into the corresponding gastrodin.
Assuntos
Benzaldeídos/metabolismo , Datura stramonium/metabolismo , Glucosídeos/biossíntese , Álcoois Benzílicos/isolamento & purificação , Álcoois Benzílicos/metabolismo , Biotransformação , Técnicas de Cultura de Células/métodos , Células Cultivadas , Datura stramonium/citologia , Glucosídeos/isolamento & purificação , Caules de Planta/citologia , Plantas Medicinais/citologia , Plantas Medicinais/metabolismoRESUMO
Free cytoplasmic informosomes isolated from Datura stramonium plants infected by PVX contain a low-molecular ribonucleoprotein complex (RNP). This complex as to its main physico-chemical parameters (sedimentation coefficient 10S, buoyant density in CsSO4 1.31 g/cm3, stability to 1% lauroylsarcosinate-Na) corresponds to the prosome (inhibitory RNP). Prosomes isolated from free mRNP of D. stramonium plants infected by PVX contain the protein of 39 kDa. This protein was shown to be capable to phosphorylate in vitro in the composition of informosomes and prosomes. It is possible that this protein can be the protein-repressor, since it is absent in the translated polysome-associated form of mRNP. The label incorporation has shown that the protein of 39 kDa is able to reduce in vitro the template activity of genomic RNA PVX to 40% and RNA TMIV--to 30%. Moreover, the protein 39 of kDa has the protease activity. It affects substrate-case in like trypsin. It is supposed that it can participate in splitting the intracellular proteins as well as in the expression of the virus genome, it can also influence the template activity of cell RNAs.
Assuntos
Datura stramonium/virologia , Potexvirus/genética , Complexo de Endopeptidases do Proteassoma/análise , RNA Viral/genética , Ribonucleoproteínas/análise , Datura stramonium/metabolismo , Regulação Viral da Expressão Gênica , Peso Molecular , Folhas de Planta/metabolismo , Folhas de Planta/virologia , Potexvirus/patogenicidade , Complexo de Endopeptidases do Proteassoma/metabolismo , Ribonucleoproteínas/metabolismo , Especificidade por SubstratoRESUMO
The strictly aerobic bacterium Vitreoscilla expresses a hemoglobin-like protein, VHb, when subjected to oxygen stress. When expressed in plants, this has several intriguing physiological effects, such as improving the overall growth rate, speeding germination and flowering, and increasing the productivity of certain oxygen-requiring metabolic pathways. Although the mechanisms behind the effects of VHb in heterologous hosts are not yet fully characterized, it has been suggested that VHb facilitates oxygen transport and/or storage. This hypothesis is supported by the kinetic properties of VHb, which allow very rapid dissociation of oxygen from the protein.
Assuntos
Bactérias Aeróbias/metabolismo , Hemoglobinas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Datura stramonium/metabolismo , Hemoglobinas/genética , Cinética , Nicotina/biossíntese , Oxigênio/metabolismo , Plantas Medicinais , Plantas Tóxicas , Escopolamina/biossíntese , Nicotiana/metabolismoRESUMO
Tropine (tropan-3 alpha-ol) is an intermediate in the formation of hyoscyamine. An acyltransferase activity that can acetylate tropine using acetylcoenzyme A as cosubstrate has been found in transformed root cultures of Datura stramonium. A further acyltransferase activity that acetylates pseudotropine (tropan-3 beta-ol) with acetyl-coenzyme A is also present. These two activities can be partially resolved by anion-exchange chromatography, some fractions containing only the pseudotropine-utilizing activity. The basic properties of these two enzymes are reported and their roles in forming the observed alkaloid spectrum of D. stramonium roots discussed.
Assuntos
Acetiltransferases/metabolismo , Datura stramonium/metabolismo , Plantas Medicinais , Plantas Tóxicas , Tropanos/metabolismo , Acetiltransferases/isolamento & purificação , Atropina/biossíntese , Cromatografia por Troca Iônica , Concentração de Íons de HidrogênioRESUMO
Isotopic labelling experiments have been carried out in Datura stramonium root cultures with the following isotopically labelled precursors; [2H3]- [2-13C, 2H3]-, [1-13C, 18O2]-acetates, 2H2O, [2H3-methyl]-methionine, [2-13C]-phenyllactate, [3-2H]-tropine and [2'-13C, 3-2H]-littorine. The study explored the incorporation of isotope into the tropane ring system of littorine 1 and hyoscyamine 2 and revealed that deuterium from acetate is incorporated only into C-6 and C-7, and not into C-2 and C-4 as previously reported. Oxygen-18 was not retained at a detectable level into the C(3)-O bond from [1-13C, 18O2]-acetate. The intramolecular nature of the rearrangement of littorine 1 to hyoscyamine 2 is revealed again by a labelling study using [2'-13C, 3-2H]-littorine, [2-13C]-phenyllactate and [3-2H]-tropine.
Assuntos
Alcaloides/biossíntese , Datura stramonium/metabolismo , Plantas Medicinais , Plantas Tóxicas , Tropanos/química , Alcaloides/química , Espectroscopia de Ressonância Magnética , Estrutura MolecularRESUMO
In tropane-alkaloid producing plants and root cultures, the reduction of tropinone is a branch-point in secondary metabolism. Two different reductases stereospecifically form the isomeric alcohols tropine (tropan-3 alpha-ol) and pseudotropine (tropan-3 beta-ol). We describe here the purification and characterization of both reductases from transformed root cultures of Datura stramonium. The tropine-forming reductase (TR I, EC 1.1.1.206) was purified 108-fold, the pseudotropine-forming enzyme (TR II, EC 1.1.1.236) was purified 3410-fold to homogeneity. The native molecular weights, both determined by gel chromatography, were 50,700 (TR I) and 77,700 (TR II). In SDS gel electrophoresis a subunit with an M(r) of 27,700 could be identified for TR II. Isoelectric points are at 5.2 (TR I) and 5.7 (TR II). Km values for the physiological substrate tropinone are 1.30 mM (TR I) and 0.11 mM (TR II). NADPH as a cosubstrate shows Km values of 58 microM (TR I) and 16 microM (TR II). NADH is not accepted by either enzyme. The reverse reaction (i.e. oxidation of the alcohol to tropinone) was found only for TR I with a Km of 180 microM. From a detailed analysis of the catalytic activities of TR I and TR II with a range of substrate analogues some key features of the mechanism of reaction can be proposed. The catalytic properties of TR I and TR II are compared with each other and with TR I and TR II activities from other solanaceous species from which these enzymes have been described.
Assuntos
Oxirredutases do Álcool/metabolismo , Datura stramonium/metabolismo , Plantas Medicinais , Plantas Tóxicas , Tropanos/metabolismo , Oxirredutases do Álcool/química , Oxirredutases do Álcool/isolamento & purificação , Catálise , Cromatografia de Afinidade , Cromatografia por Troca Iônica , Eletroforese em Gel de Poliacrilamida , Peso Molecular , Oxirredução , Especificidade por SubstratoRESUMO
The enzymes N-methylputrescine oxidase (MPO), the tropine-forming tropinone reductase (TRI), the pseudotropine-forming tropinone reductase (TRII), the tropine:acyl-CoA transferase (TAT) and the pseudotropine:acyl-CoA transferase (PAT) extracted from transformed root cultures of Datura stramonium and a Brugmansia candida x aurea hybrid were tested for their ability to accept a range of alternative substrates. MPO activity was tested with N-alkylputrescines and N-alkylcadaverines as substrates. TRI and TRII reduction was tested against a series of N-alkylnortropinones, N-alkylnorpelletierines and structurally related ketones as substrates. TAT and PAT esterification tests used a series of N-substituted tropines, pseudotropines, pelletierinols and pseudopelletierinols as substrates to assess the formation of their respective acetyl and tigloyl esters. The results generally show that these enzymes will accept alien substrates to varying degrees. Such studies may shed some light on the overall topology of the active sites of the enzymes concerned.
Assuntos
Datura stramonium/enzimologia , Plantas Medicinais , Plantas Tóxicas , Tropanos/metabolismo , Datura stramonium/metabolismo , Cromatografia Gasosa-Espectrometria de Massas/métodos , Raízes de Plantas/enzimologia , Raízes de Plantas/metabolismo , Putrescina/análogos & derivados , Putrescina/metabolismo , Especificidade por SubstratoRESUMO
The conversion of littorine to hyoscyamine has been investigated by feeding deuterium labelled (RS)-[2-(2)H]-, [3, 3-(2)H(2)]-, [2, 3, 3-(2)H(3)]- phenyllactic acids to transformed root cultures of Datura stramonium. Isolation and GC-MS analyses of the isotope incorporation into the resultant hyoscyamine does not support the involvement of a vicinal interchange process operating during the isomerisation of littorine to hyoscyamine. Additionally a metabolism study with [1'-13C, 3', 3'-(2)H(2)]-hyoscyamine has established that the alkaloid is metabolically stable at C-3' with no evidence for a reversible in vivo oxidation process to the corresponding aldehyde. The data do not support an S-adenosy-L-methionine (SAM 5)/co-enzyme-B(12) mediated process for the isomerisation of littorine to hyoscyamine.
Assuntos
Derivados da Atropina/metabolismo , Atropina/biossíntese , Atropina/metabolismo , Datura stramonium/metabolismo , Atropina/química , Derivados da Atropina/química , Isótopos de Carbono , Extratos Celulares , Células Cultivadas , Cobamidas/metabolismo , Datura stramonium/citologia , Deutério , Cromatografia Gasosa-Espectrometria de Massas , Isomerismo , Cinética , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Oxirredução , Raízes de Plantas/citologia , Raízes de Plantas/metabolismo , S-Adenosilmetionina/metabolismoRESUMO
The metabolism of the environmental estrogen bisphenol A (BPA) was studied in heterotrophic plant cell suspension cultures of soybean (Glycine max), wheat (Triticum aestivum), foxglove (Digitalis purpurea), and thorn apple (Datura stramonium), which were regarded as metabolic model systems for intact plants. Three main metabolic routes of BPA were observed in the tissues. Most of the radioactivity found in the cell extracts consisted of carbohydrate conjugates of BPA amounting to about 85% (foxglove), 80% (wheat), 7% (soybean) and 15% (thorn apple) of applied 14C. The second main route was formation of non-extractable residues. Portions detected were low in foxglove (3.9% of applied 14C), moderate in wheat (13.5%), high in thorn apple (27.4%) and soybean (49.4%). With thorn apple, BPA derived bound residues were preponderantly resistant towards acid treatment; only traces of BPA were released. The third route was the formation of a highly polar, presumably polymeric material detected in media of soybean and thorn apple (29.3% and 36.0% of applied 14C, respectively). The mechanism of its formation remained unknown. In thorn apple, this highly polar material was formed extremely rapidly, and was considerably stable. Only traces of BPA were liberated by hydrolytic treatment with cellulase or acid. During hydrolysis experiments with glycoside fractions, non-extractable residues and highly polar materials, low amounts of presumably primary metabolites of BPA (up to 6% of applied 14C) were detected besides the parent compound; their chemical structures remained unclear.