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Secondary Metabolites (secondary + metabolite)
Kinds of Secondary Metabolites Terms modified by Secondary Metabolites Selected AbstractsSecondary Metabolites of Phomopsis sp.EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 18 2009XZ-2, an Endophytic Fungus from Camptothecaacuminate Abstract Eleven new metabolites, including nine lovastatin analogues [oblongolides N,V (1,2 and 5,11), which were defined as naphthalene-type fungal polyketides], one linear furanopolyketide (13) and a monoterpene named dihydroxysabinane (14), together with four known compounds including oblongolides B (3) and C (4), one linear furanopolyketide (12) and the sesterterpene terpestacin (15), were isolated from the endophytic fungal strain Phomopsis sp. XZ-26 of Camptotheca acuminate. Their structures were elucidated by spectroscopic analyses including HR-ESI-MS, 1H and 13C NMR, 2D NMR (HMQC, HMBC, 1H- 1H COSY and NOESY), and X-ray single-crystal analysis. The antimicrobial activities of 1,5, 8, 10 and 13,15 were evaluated, but none showed a substantial effect. Additionally, a hypothetical biosynthetic pathway for oblongolides was proposed.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Triumfettamide and Triumfettoside Ic, Two Ceramides and Other Secondary Metabolites from the Stems of Wild Triumfetta cordifoliaA.HELVETICA CHIMICA ACTA, Issue 7 2008Rich. (Tiliaceae) Abstract Two new ceramides, triumfettamide (1) and triumfettoside Ic (2), characterized as (2R,6Z)-2-hydroxy- N -[(2S,3S,4R)-1,3,4-trihydroxyhexacosan-2-yl]heptadec-6-enamide and (2R)- N -{(1S,2R,3E,6Z, 9Z,12Z,15Z)-1-[(, - D -glucopyranosyloxy)methyl]-2-hydroxyheneicosa-3,6,9,12,15-pentaen-1-yl}-2-hydroxytetradecanamide, respectively, were isolated from the stems of Triumfetta cordifoliaA. Rich. besides eight known secondary metabolites identified as heptadecanoic acid, , -sitosterol glucopyranoside, friedelin, lupeol, betulin, maslinic acid, 2-hydroxyoleanolic acid and the mixture of stigmasterol and , -sitosterol. Their structures were determined on the basis of spectroscopic methods as well as HR-MALDI-FT-ICR-MS analysis, chemical transformation, and by comparison of their physical and spectral data with those reported in the literature and with authentic specimens for some known compounds. Five pentacyclic triterpenoids, friedelin, lupeol, betulin, maslinic acid, and 2-hydroxyoleanolic acid, have been isolated from Triumfetta genus for the first time. [source] Secondary Metabolites from the Fungus Chaetomium brasilienseHELVETICA CHIMICA ACTA, Issue 1 2008Guo-You Li Abstract Two new depsidones, mollicellins I and J (1 and 2, resp.), and a new chromone, 2-(hydroxymethyl)-6-methylmethyleugenin (3), along with six known compounds, 4,9, were isolated from the ethyl acetate extract of a solid-state fermented culture of Chaetomium brasiliense. Their structures were elucidated based on spectroscopic analysis. Mollicellins I and H (5) exhibited significant growth inhibitory activity against human breast cancer (Bre04), human lung (Lu04), and human neuroma (N04) cell lines with GI50 values between 2.5,8.6,,g/ml. [source] Phenylnannolones A,C: Biosynthesis of New Secondary Metabolites from the Myxobacterium Nannocystis exedensCHEMBIOCHEM, Issue 18 2008Birgit Ohlendorf Abstract Myxobacteria are gliding bacteria that belong to the ,-Proteobacteria and are known for their unique biosynthetic capabilities. Among myxobacteria, Nannocystis spp. are most closely related to marine myxobacteria and their secondary metabolism has hardly been investigated. Phenylnannolones A (1), B (2) and C (3) were obtained from a culture of Nannocystis exedens that was isolated from the intertidal region of Crete. Compound 1 had inhibitory activity toward the ABCB1 gene product P-glycoprotein and reversed daunorubicin resistance in cultured cancer cells. Phenylnannolone A has an unusual structural architecture; it is composed of an ethyl-substituted polyene chain linked to a pyrone moiety on one side and to a phenyl ring on the other. The investigation of the biosynthesis with labelled precursors revealed acetate, butyrate and phenylalanine as building blocks for 1. The labelling pattern suggested novel biochemical reactions for the biosynthesis of the starter unit. [source] Active Secondary Metabolites from Fungi.CHEMINFORM, Issue 4 2006Part 22. Abstract For Abstract see ChemInform Abstract in Full Text. [source] Within population variation and interrelationships between morphology, nutritional content, and secondary compounds of Rhamnus alaternus fruitsNEW PHYTOLOGIST, Issue 2 2002Ido Izhaki Summary ,,We studied within-species variation in and interrelations among morphological and chemical traits of ripe Mediterranean buckthorn ( Rhamnus alaternus ) fruit, a bird-dispersed species. ,,Principal component analysis revealed that larger fruits tended to be relatively rich in nonstructural carbohydrates (NSC), water and P but poor in protein and most minerals. Small fruits tended to be relatively rich in protein, structural carbohydrates, K and Zn while intermediate size fruits tended to be rich in lipids, Mg and Ca. Variation in chemical traits (organic compounds and minerals) was typically much higher than in morphological traits (e.g. fruit size) with the exception of NSC and water content, which varied little. This discrepancy might be explained by differences in environmental conditions between plant microsites that imposed greater variability on fruit nutrient composition than on fruit-morphological traits; and by lower selective pressure by birds on fruit chemical traits than on morphological traits. ,,Secondary metabolite (emodin) concentration was positively correlated with concentrations of NSC, supporting the nutrient/toxin titration model, which predicts that high levels of secondary metabolites in fruits should be off set by high nutritional rewards for dispersers. ,,Emodin concentration in leaves was much higher than in fruit pulp, which may indicate its differential adaptive roles in seed dispersal and against herbivores. [source] Post-ingestive effects of nectar alkaloids depend on dominance status of bumblebeesECOLOGICAL ENTOMOLOGY, Issue 4 2009JESSAMYN S. MANSON Abstract 1.,Secondary metabolites have acute or chronic post-ingestive effects on animals, ranging from death to growth inhibition to reduced nutrient assimilation. 2.,Although characterised as toxic, the nectar of Gelsemium sempervirens is not lethal to pollinators, even when the concentration of the nectar alkaloid gelsemine is very high. However, little is known about the sublethal costs of nectar alkaloids. 3.,Using a microcolony assay and paired worker bumblebees, the present study measured the effects of artificial nectar containing gelsemine on oocyte development. Oocytes are a sensitive indicator of protein utilisation and general metabolic processes. We also calculated carbohydrate concentrations in the haemolymph to examine energetic costs of gelsemine consumption. 4.,High concentrations of gelsemine significantly reduced mean oocyte width in subordinate bees, while dominant bees showed only a trend towards oocyte inhibition. Gelsemine consumption did not reduce carbohydrate concentrations in haemolymph. 5.,The cost of ingesting gelsemine may be due to direct toxicity of alkaloids or may be an expense associated with detoxifying gelsemine. Detoxification of alkaloids can require reallocation of resources away from essential metabolic functions like reproduction. The risks associated with nectar alkaloid consumption are tied to both the social and nutritional status of the bee. [source] Secondary metabolites from Paronychia argenteaMAGNETIC RESONANCE IN CHEMISTRY, Issue 1 2008Alessandra Braca Abstract Two new oleanane saponins (1 and 2) and one new flavonol glycoside (3) together with six known flavonoids, were isolated from the aerial parts of Paronychia argentea. Their structures were elucidated by 1D and 2D NMR experiments including 1D-TOCSY, DQF-COSY, NOESY, HSQC, and HMBC spectroscopy, as well as ESI-MS analysis. Copyright © 2007 John Wiley & Sons, Ltd. [source] Bioreactor for cultivation of red beet hairy roots and in situ recovery of primary and secondary metabolitesENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 3 2009Bhagyalakshmi Neelwarne Abstract To arrive at an appropriate bioreactor design and in situ recovery of the products, red beet hairy roots were used as a model system where the levels of betalain pigments (betacyanins and betaxanthins) were followed as secondary metabolite and the peroxidase enzyme as primary metabolite. Medium volume and other kinetic parameters were found to play significant roles by way of directly affecting the biomass yield rather than a specific metabolite. The hydrodynamic stress created on the roots by large culture volume could be minimized by pulse-feeding of medium in shake-flasks; and by separating the biomass chamber from the aerated medium reservoir in circulatory fed-batch bioreactor. Accordingly the bioreactor was modified to provide anchorage and air-enrichment chamber which resulted in higher formation of both the metabolites than in shake-flasks. Various down-stream processing aspects such as in situ release of pigments by non-destructive methods, followed by adsorption through a column and recovery by desorption were optimized for betalains. A strategy for simultaneous recovery of pigment and peroxidase was worked out using aqueous two phase extraction (ATPE). [source] Effects of oleoresins and monoterpenes on in vitro growth of fungi associated with pine decline in the Southern United StatesFOREST PATHOLOGY, Issue 3 2009L. G. Eckhardt Summary As a means of exploring pine resistance to root disease and declines, the effects of host plant secondary metabolites on the growth of root colonizing fungi associated with three diseases/declines of southern pines , loblolly pine decline, littleleaf disease and annosum root rot were tested. The associated fungi ,Leptographium huntii, L. serpens, L. terebrantis, L. procerum, Heterobasidion annosum and Phytophthora cinnamomi, were grown in saturated atmospheres or in direct contact with, pure monoterpenes and crude oleoresin collected from the four southern pines (Pinus taeda, P. eschinata, P. palustris and P. elliotti) for 7 day. Fungal growth was measured at 3, 5 and 7 day. Root-infecting fungi differed significantly in sensitivity to crude oleoresin and pure monoterpenes. All fungi tested were inhibited, to some extent, by the resins tested. H. annosum and P. cinnamomi were strongly inhibited by all the monoterpenes tested. The ophiostomatoid fungi were significantly less affected by the compounds tested. L. huntii and L. serpens were less inhibited by monoterpenes than either L. terebrantis or L. procerum. These fungal growth studies show that the kind and amount of secondary metabolite produced by the host plant have a profound effect on tree pathogens. Alterations of tree physiology may have implications for defenses against tree pathogens as well as to the ecology and management of forest ecosystems. Difference in incidence of root disease observed in the field may be explained by the ability of the fungus to tolerate these host defense mechanisms. [source] Two cinnamate derivatives produce similar alteration in mRNA expression and activity of antioxidant enzymes in ratsJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 5 2003Mi-Kyung Lee Abstract Cinnamate is a widespread secondary metabolite of phenolic compound synthesized by plants for defensive purposes. The current study was designed to investigate the effect of two structurally related cinnamate derivatives, 4-hydroxycinnamate and 3-(4-hydroxyphenyl)propionic acid (HPP), on the mRNA expression and activity of antioxidant enzymes in high-cholesterol-fed rats. Male rats were fed a 1 g/100 g high-cholesterol diet with supplements of either 4-hydroxycinnamate or HPP (0.135 mmol/100 g diet) for 6 weeks. The plasma paraoxonase activity was found to be higher in the cinnamate-derivative-supplemented groups than in the control group. The erythrocyte superoxide dismutase (SOD) and catalase (CAT) activities, plus glutathione (GSH) level, were all significantly higher in the 4-hydroxycinnamate- and HPP-supplemented groups than in the control group. However, both 4-hydroxycinnamate and HPP supplementation significantly lowered the hepatic activities and mRNA expression of CAT and glutathione peroxidase (GSH-Px) compared to the control group. The hepatic mRNA expression and activity of SOD did not differ between the groups. The hepatic thiobarbituric acid reactive substances (TBARS) level was significantly lowered by the 4-hydroxycinnamate and HPP supplementation. Accordingly, these results indicate that supplementation by 4-hydroxycinnamate and HPP would seem to enhance the antioxidative defense of erythrocyte. Both HPP and 4-hydroxycinnamate would appear to be beneficial in improving the function of antioxidative enzymes on a molecular level in high-cholesterol-fed rats. © 2003 Wiley Periodicals, Inc. J Biochem Mol Toxicol 17:255,262, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.10087 [source] Enhanced production of lovastatin in a bubble column by Aspergillus terreus using a two-stage feeding strategyJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2007EM Rodríguez Porcel Abstract A two-stage feeding strategy is shown to improve the rate of production of lovastatin by Aspergillus terreus when compared with conventional batch fermentation. The feeding strategy consisted of an initial batch/fed-batch phase and a semi-continuous culture dilution phase with retention of pelleted biomass in a slurry bubble column reactor. The batch phase served only to build up the biomass for producing lovastatin, a secondary metabolite that inhibits its own synthesis in the producing microfungus. The semi-continuous dilution phase provided nutrients to sustain the fungus, but prevented biomass growth by limiting the supply of essential nitrogen. (Synthesis of lovastatin does not require nitrogen.) The preferred pelleted growth morphology that favors lovastatin synthesis was readily obtained and maintained in the 20 L bubble column used. In contrast, a stirred tank fermentation had a substantially lower production of lovastatin because mechanical agitation damaged the fungal pellets. The two-stage feeding method increased lovastatin production rate by more than 50% in comparison with the conventional batch operation. Rheological data for the fungal broth are presented. Copyright © 2007 Society of Chemical Industry [source] The evolution of secondary metabolism , a unifying modelMOLECULAR MICROBIOLOGY, Issue 5 2000Richard D. Firn Why do microbes make secondary products? That question has been the subject of intense debate for many decades. There are two extreme opinions. Some argue that most secondary metabolites play no role in increasing the fitness of an organism. The opposite view, now widely held, is that every secondary metabolite is made because it possesses (or did possess at some stage in evolution) a biological activity that endows the producer with increased fitness. These opposing views can be reconciled by recognizing that, because of the principles governing molecular interactions, potent biological activity is a rare property for any molecule to possess. Consequently, in order for an organism to evolve the rare potent, biologically active molecule, a great many chemical structures have to be generated, most of which will possess no useful biological activity. Thus, the two sides of the debate about the role and evolution of secondary metabolism can be accommodated within the view that the possession of secondary metabolism can enhance fitness, but that many products of secondary metabolism will not enhance the fitness of the producer. It is proposed that secondary metabolism will have evolved such that traits that optimize the production and retention of chemical diversity at minimum cost will have been selected. Evidence exists for some of these predicted traits. Opportunities now exist to exploit these unique properties of secondary metabolism to enhance secondary product diversity and to devise new strategies for biotransformation and bioremediation. [source] Mycosporine-glutamicol-glucoside: a natural UV-absorbing secondary metabolite of rock-inhabiting microcolonial fungiRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 9 2003Marc Volkmann Microcolonial ascomycetes are known to inhabit bare rock surfaces in cold and hot deserts and thus are habitually exposed to high levels of solar radiation. Several of these stress-tolerant fungal isolates, cultivated in the laboratory under daylight illumination, were studied for the presence of effective UV-radiation protection substances. Liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) analyses allowed for efficient separation and structure clarification of two mycosporines. It was demonstrated that both mycosporine-glutamicol-glucoside and mycosporine-glutaminol-glucoside are natural and constitutive secondary metabolites of microcolonial fungi. The function and relation of these substances in the fungal cell are discussed. Copyright © 2003 John Wiley & Sons, Ltd. [source] Characterisation of the human liver in vitro metabolic pattern of artemisinin and auto-induction in the rat by use of nonlinear mixed effects modellingBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 2 2003Ulrika S.H. Svensson Abstract Aims: The aims of the study were to characterise the metabolic pattern of artemisinin in human and rat liver microsomes and to assess the magnitude of auto-induction in the rat. Methods: 14C-artemisinin was incubated with human liver microsomes and with liver microsomes from rats pretreated with oral artemisinin or placebo. The metabolic fate of 14C-artemisinin in microsomes from human B-lymphoblastoid cell lines transformed with CYP2A6, CYP2B6 and CYP3A4 was also investigated. The human liver microsome data and the rat liver microsomes data were analysed by nonlinear mixed effects modelling and naďve pooling using NONMEM, respectively. Results: Four metabolites were radiometrically detected in experiments with rat liver microsomes. The model that best described the data involved three primary metabolites of which one metabolite was further metabolised to a secondary metabolite. The formation of the four metabolites was induced 2.8, 7.2, 4.8 and 2.5-fold, respectively, in liver microsomes from rats pre-treated with artemisinin. Three metabolites were formed in human liver microsomes; having the same retention times as three of the metabolites formed in the rat. The final model consisted of two primary metabolites and a secondary metabolite with CYP2B6 and CYP2A6 influencing the formation rates of the major and minor primary metabolites, respectively. Conclusions: CYP2B6 and CYP2A6 activities described variability in the formation of the major and minor primary metabolites, respectively, in human liver microsomes. All artemisinin metabolic pathways in rat liver microsomes were induced in artemisinin pretreated animals. We suggest modelling as a method for the discrimination and detection of more complex metabolic patterns from in vitro metabolism rate data. Copyright © 2002 John Wiley & Sons, Ltd. [source] Growth Behavior in Plant Cell Cultures Based on Emissions Detected by a Multisensor ArrayBIOTECHNOLOGY PROGRESS, Issue 4 2004Palle Komaraiah The use of a multisensor array based on chemical gas sensors to monitor plant cell cultures is described. The multisensor array, also referred to as an electronic nose, consisted of 19 different metal oxide semiconductor sensors and one carbon dioxide sensor. The device was used to continuously monitor the off-gas from two plant cell suspension cultures, Morinda citrifolia and Nicotiana tabacum, cultivated under batch conditions. By analyzing the multiarray responses using two pattern recognition methods, principal component analysis and artificial neural networks, it was possible to monitor the course of the cultivations and, in turn, to predict (1) the biomass concentration in both systems and (2) the formation of the secondary metabolite, antraquinone, by M. citrifolia. The results identify the multisensor array method as a potentially useful analytical tool for monitoring plant process variables that are otherwise difficult to analyze on-line. [source] Cloning, expression, crystallization and preliminary X-ray analysis of the XMT and DXMT N -methyltransferases from Coffea canephora (robusta)ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2007Laurent Biget Caffeine is a secondary metabolite produced by a variety of plants including Coffea canephora (robusta) and there is growing evidence that caffeine is part of a chemical defence strategy protecting young leaves and seeds from potential predators. The genes encoding XMT and DXMT, the enzymes from Coffea canephora (robusta) that catalyse the three independent N -methyl transfer reactions in the caffeine-biosynthesis pathway, have been cloned and the proteins have been expressed in Escherichia coli. Both proteins have been crystallized in the presence of the demethylated cofactor S -adenosyl- l -cysteine (SAH) and substrate (xanthosine for XMT and theobromine for DXMT). The crystals are orthorhombic, with space group P212121 for XMT and C2221 for DXMT. X-ray diffraction to 2.8,Ĺ for XMT and to 2.5,Ĺ for DXMT have been collected on beamline ID23-1 at the ESRF. [source] 3- O -Methylfunicone, a metabolite produced by Penicillium pinophilum, modulates ERK1/2 activity, affecting cell motility of human mesothelioma cellsCELL PROLIFERATION, Issue 2 2010E. Buommino Objectives:, 3- O -methylfunicone (OMF), a secondary metabolite produced by Penicillium pinophilum, affects cell proliferation and motility in a variety of human solid tumours. The aim of this study was to demonstrate whether OMF has the ability to arrest cell division and motility, in a human mesothelioma cell line. Malignant mesothelioma is an aggressive cancer that does not respond to standard therapies the cells of which are considered to be highly resistant to apoptosis. Material and methods:, Cell motility and invasion were measured using a modified Boyden chamber. Gene expression was examined by RT-PCR, while ERK1/2 was investigated by Western blot analysis. All experiments were also performed on primary cultures of mesothelial cells. Results:, The present study shows that OMF inhibited motility of the NCI mesothelioma cell line by modulating ERK signalling activity, and affected ,V,5 integrin and MMP-2 expression, inducing marked downregulation at both mRNA and protein levels. Substantial downregulation of VEGF gene expression was also demonstrated. These effects were not observed in normal mesothelial cell cultures. Conclusion:, OMF may have potential as a naturally derived anti-tumour drug for treatment of mesothelioma. [source] 3- O -Methylfunicone, a secondary metabolite produced by Penicillium pinophilum, induces growth arrest and apoptosis in HeLa cellsCELL PROLIFERATION, Issue 6 2004E. Buommino The aim of this study was to investigate the mechanisms by which such properties are exerted, with special reference to any anti-proliferative and apoptotic potential, on HeLa cells. OMF treatment caused about 44% inhibition of cell growth after 24 h, and modifications in the tubulin fibre organization. In addition, a significant increase in p21 mRNA expression and a decrease in cyclin D1 and Cdk4 mRNA expression resulted at the same time. Apoptosis induction was demonstrated by the annexin V assay, cytofluorimetric analysis of the DNA content of the sub-G1 fraction and DNA laddering. Taken together, our data showed that the compound inhibits proliferation of HeLa cells by several mechanisms, such as disruption of tubulin fibres, cell cycle arrest and apoptosis induction. The capacity of the compound to affect the cell cycle and to modulate apoptosis is indicative of a potential for the development of a new agent for cancer chemotherapy. [source] Cephalosol: An Antimicrobial Metabolite with an Unprecedented Skeleton from Endophytic Cephalosporium acremonium IFB-E007CHEMISTRY - A EUROPEAN JOURNAL, Issue 34 2008Wei Zhang Dr. Abstract Cephalosol (1), a potent antimicrobial secondary metabolite with a new carbon skeleton, was characterized from the culture of Cephalosporium acremonium IFB-E007 that used to reside as an endophyte in Trachelospermum jasminoides (Apocynaceae). Its structure and absolute configuration were unambiguously determined by spectroscopic and computational approaches. [source] Initial stages of neural regeneration in Helisoma trivolvis are dependent upon PLA2 activityDEVELOPMENTAL NEUROBIOLOGY, Issue 4 2003Matthew S. Geddis Abstract Neuronal regeneration after damage to an axon tract requires the rapid sealing of the injured plasma membrane and the subsequent formation of growth cones that can lead regenerating processes to their appropriate target. Membrane sealing and growth cone formation are Ca2+ -dependent processes, but the signaling pathways activated by Ca2+ to bring about these effects remain poorly understood. An in vitro injury model was employed in which neurites from identified snail neurons (Helisoma trivolvis) were transected with a glass microknife, and the formation of new growth cones from the distal portions of transected neurites was recorded at defined times after transection. This study presents three main results. First, phospholipase A2 (PLA2), a calcium-activated enzyme, is necessary for membrane sealing in vitro. Second, PLA2 activity is also required for the formation of a new growth cone after the membrane has sealed successfully. Thus, PLA2 plays a dual role by affecting both growth cone formation and membrane sealing. Third, the injury-induced activation of PLA2 by Ca2+ controls growth cone formation through the production of leukotrienes, secondary metabolites of PLA2 activity. Taken together, these results suggest that the injury-induced Ca2+ influx acts via PLA2 and leukotriene production to assure growth cone formation. These findings indicate that events that cause an inhibition of PLA2 or lipoxygenases, enzymes that produce leukotrienes, could result in the inability of neurites to regenerate. © 2003 Wiley Periodicals, Inc. J Neurobiol 54: 555,565, 2003 [source] The carbon,nutrient balance hypothesis: its rise and fallECOLOGY LETTERS, Issue 1 2001J.G. Hamilton The idea that the concentration of secondary metabolites in plant tissues is controlled by the availability of carbon and nitrogen in the environment has been termed the carbon,nutrient balance hypothesis (CNB). This hypothesis has been invoked both for prediction and for post hoc explanation of the results of hundreds of studies. Although it successfully predicts outcomes in some cases, it fails to such an extent that it cannot any longer be considered useful as a predictive tool. As information from studies has accumulated, many attempts have been made to save CNB, but these have been largely unsuccessful and have managed only to limit its utility. The failure of CNB is rooted in assumptions that are now known to be incorrect and it is time to abandon CNB because continued use of the hypothesis is now hindering understanding of plant,consumer interactions. In its place we propose development of theory with a firm evolutionary basis that is mechanistically sophisticated in terms of plant and herbivore physiology and genetics. [source] Capillary electrophoresis-mass spectrometry characterisation of secondary metabolites from the antihyperglycaemic plant Genista teneraELECTROPHORESIS, Issue 11 2006Emma L. Edwards Abstract Genista tenera is endemic to the Portuguese island of Madeira, where an infusion of the aerial parts of the plant is used in folk medicine as an antidiabetic agent. Consequently the medicinal properties of the secondary metabolites of this plant have been the subject of an ongoing study. A recently reported LC-MS method using a 100,min separation allowed identification of five flavonoid components in an extract of the aerial parts of this plant. In order to obtain additional information on the range and complexity of the plant's secondary metabolite components a CE-MS method has been developed and applied for the analysis of an extract of G.,tenera. Twenty-six different components are distinguished in an analysis time of only 10,min. Results demonstrate that CE-MS/MS rapidly generates data complementary to those obtainable by LC-MS/MS and is particularly suited to the analysis of plant metabolites where concentration is not limiting. [source] Bioreactor for cultivation of red beet hairy roots and in situ recovery of primary and secondary metabolitesENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 3 2009Bhagyalakshmi Neelwarne Abstract To arrive at an appropriate bioreactor design and in situ recovery of the products, red beet hairy roots were used as a model system where the levels of betalain pigments (betacyanins and betaxanthins) were followed as secondary metabolite and the peroxidase enzyme as primary metabolite. Medium volume and other kinetic parameters were found to play significant roles by way of directly affecting the biomass yield rather than a specific metabolite. The hydrodynamic stress created on the roots by large culture volume could be minimized by pulse-feeding of medium in shake-flasks; and by separating the biomass chamber from the aerated medium reservoir in circulatory fed-batch bioreactor. Accordingly the bioreactor was modified to provide anchorage and air-enrichment chamber which resulted in higher formation of both the metabolites than in shake-flasks. Various down-stream processing aspects such as in situ release of pigments by non-destructive methods, followed by adsorption through a column and recovery by desorption were optimized for betalains. A strategy for simultaneous recovery of pigment and peroxidase was worked out using aqueous two phase extraction (ATPE). [source] Lymantria dispar herbivory induces rapid changes in carbon transport and partitioning in Populus nigraENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2008Benjamin A. Babst Abstract We tested for rapid changes in photosynthate transport and partitioning in response to Lymantria dispar (L.) (Lepidoptera: Lymantriidae) (gypsy moth) herbivory in Populus nigra L. (Salicaceae). Transport and partitioning of [11C]-photosynthate from young mature leaves were measured in vivo before and 18 h after leaf chewing by gypsy moth larvae, which were caged on three older leaves. Following herbivory, there was an increase in export speed of recently fixed carbon from younger mature leaves. The increased export speed was due to a quicker transit time of 11C through the leaf, rather than a change in transport speed through the phloem. Additionally, basipetal partitioning of [11C]-photosynthate was increased following herbivory. Neither of these changes was observed in control plants. This enhancement of export occurs even though herbivores are well known to induce increases in carbon allocation to secondary metabolites within leaves. Our results demonstrate that the use of non-destructive imaging of 11C tracer is a powerful tool for examining plant responses to herbivory. Although the mechanisms underlying the rapid increase in carbon flux to stems and roots remain to be elucidated, our results raise the possibility of a coordinated whole plant response to herbivory. Thus, even when the herbivore specializes on only one plant tissue type, a whole plant approach may be key to understanding how plants respond to herbivory. [source] Trade-offs in oviposition choice?ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2007Food-dependent performance, defence against predators of a herbivorous sawfly Abstract The sawfly Athalia rosae L. (Hymenoptera: Tenthredinidae) is a feeding specialist on plant species of the Brassicaceae, which are characterised by secondary metabolites, called glucosinolates. The larvae can take up the respective glucosinolates of their hosts and concentrate them in their haemolymph to protect themselves against predators. Oviposition preferences of naďve females were tested for three species, Sinapis alba L., Brassica nigra (L.) Koch, and Barbarea stricta Andrz., and were related to larval performance patterns. Larvae were reared on either one of these plants and it was investigated how host-plant quality influences both the developmental times and growth of larvae (bottom-up) and the defence efficiency against predators (top-down). Innately, almost all adult females avoided B. stricta for oviposition and clearly preferred B. nigra over S. alba. On average, larvae developed best on B. nigra. Female larvae reached similar final body masses on all host-plant species, but males reared on S. alba were slightly lighter. The developmental time of larvae reared on B. stricta was significantly longer than on the other two plants. However, larvae reared on B. stricta were best protected against the predatory wasp Polistes dominulus Christ (Hymenoptera: Vespidae). The wasps rejected these larvae most often, while they attacked larvae reared on S. alba most frequently. Thus, larvae feeding on B. stricta theoretically run a higher risk of predation due to a prolonged developmental time, but in practice they are better protected against predators. Overall, oviposition preferences of A. rosae seem to be more influenced by bottom-up effects on larval performance than by top-down effects. [source] Strategies for the Synthesis of Stemona Alkaloids,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 15 2009Ramon Alibés Abstract The extracts of several plants of the Stemonaceae family have long been used in Asian countries against differentdiseases and for their antiparasitic properties. Significant constituents of these extracts are a series of structurally related secondary metabolites named Stemona alkaloids. All the Stemona alkaloids are polycyclic and contain multiple stereocenters. Most of them present a central pyrrolo[1,2- a]azepine system and the majority also incorporate at least one ,-methyl-,-butyrolactone substructure. Their challenging molecular architectures have motivated the development of new strategies for the construction of their skeletons, but only a small number of total syntheses have been published and they are still limited to quite a small number of targets. This microreview briefly examines most of the synthetic approaches to these alkaloids, according to the strategies devised to assemble their intricate structures, stressing the main similarities and differences encountered in the work developed by different laboratories, as well as the variations introduced along the synthetic route when pursuing different alkaloids through a common strategy. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Molecular cloning and heterologous expression of novel glucosyltransferases from tobacco cultured cells that have broad substrate specificity and are induced by salicylic acid and auxinFEBS JOURNAL, Issue 14 2001Goro Taguchi Scopoletin is one of the phytoalexins in tobacco. Cells of the T-13 cell line (Nicotiana tabacum L. Bright Yellow) accumulate a large amount of scopoletin, also known as 7-hydroxy-6-methoxycoumarin, as a glucoconjugate, scopolin, in vacuoles. We report here the molecular cloning of glucosyltransferases that can catalyze the glucosylation of many kinds of secondary metabolites including scopoletin. Two cDNAs encoding glucosyltransferase (NtGT1a and NtGT1b) were isolated from a cDNA library derived from the tobacco T-13 cell line by screening with heterologous cDNAs as a probe. The deduced amino-acid sequences of NtGT1a and NtGT1b exhibited 92% identity with each other, ,,20,50% identities with other reported glucosyltransferases. Heterologous expression of these genes in Escherichia coli showed that the recombinant enzymes had glucosylation activity against both flavonoids and coumarins. They also strongly reacted with 2-naphthol as a substrate. These recombinant enzymes can utilize UDP-glucose as the sugar donor, but they can also utilize UDP-xylose as a weak donor. RNA blot analysis showed that these genes are induced by salicylic acid and auxin, but the time course of the expression was different. This result is similar to the changes in scopoletin glucosylation activity in these tobacco cells after addition of these plant growth regulators. These results might suggest that one of the roles of the products of these genes is scopoletin glucosylation, in response to salicylic acid and/or auxin, together with the other glucosyltransferases in tobacco cells. [source] The expansion of mechanistic and organismic diversity associated with non-ribosomal peptidesFEMS MICROBIOLOGY LETTERS, Issue 2 2000Michelle C Moffitt Abstract Non-ribosomal peptides are a group of secondary metabolites with a wide range of bioactivities, produced by prokaryotes and lower eukaryotes. Recently, non-ribosomal synthesis has been detected in diverse microorganisms, including the myxobacteria and cyanobacteria. Peptides biosynthesized non-ribosomally may often play a primary or secondary role in the producing organism. Non-ribosomal peptides are often small in size and contain unusual or modified amino acids. Biosynthesis occurs via large modular enzyme complexes, with each module responsible for the activation and thiolation of each amino acid, followed by peptide bond formation between activated amino acids. Modules may also be responsible for the enzymatic modification of the substrate amino acid. Recent analysis of biosynthetic gene clusters has identified novel integrated, mixed and hybrid enzyme systems. These diverse mechanisms of biosynthesis result in the wide variety of non-ribosomal peptide structures and bioactivities seen today. Knowledge of these biosynthetic systems is rapidly increasing and methods of genetically engineering these systems are being developed. In the future, this may lead to rational drug design through combinatorial biosynthesis of these enzyme systems. [source] Factors affecting secondary metabolite production in plants: volatile components and essential oilsFLAVOUR AND FRAGRANCE JOURNAL, Issue 4 2008A. Cristina Figueiredo Abstract The presence, yield and composition of secondary metabolites in plants, viz. the volatile components and those occurring in essential oils, can be affected in a number of ways, from their formation in the plant to their final isolation. Several of the factors of influence have been studied, in particular for commercially important crops, to optimize the cultivation conditions and time of harvest and to obtain higher yields of high-quality essential oils that fit market requirements. In addition to the commercial importance of the variability in yield and composition, the possible changes are also important when the essential oils and volatiles are used as chemotaxonomic tools. Knowledge of the factors that determine the chemical variability and yield for each species are thus very important. These include: (a) physiological variations; (b) environmental conditions; (c) geographic variations; (d) genetic factors and evolution; (e) political/social conditions; and also (f) amount of plant material/space and manual labour needs. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||||||||||||||||||||