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Metabolite Production (metabolite + production)
Kinds of Metabolite Production Selected AbstractsP71 Metabolism of delta-3-Carene by human cytochrom 450 enzymesCONTACT DERMATITIS, Issue 3 2004Mike Duisken Occupational exposure to monoterpenes occurs in saw mills, particle-board plants, carpentry shops and other types of wood-treating industries. The bicyclic monoterpene delta-3-Carene, one of the components of turpentine, may irritate the skin and muceous membranes and prolonged exposure may result in allergic contact dermatitis or chronic lung function impairment. The effects of low concentrations of delta-3-Carene on alveolar macrophages in vitro were examined and a dose-dependent relationship between the cell viability and the delta-3-Carene concentration was found. Little is known about the metabolism of delta-3-Carene in mammalians. In order to determine the toxic potential of this monoterpene we studied the human metabolism of delta-3-Carene in vitro. Therefore we used pooled human liver S9 and human liver microsomal cytochrome P450 enzymes. By using GC-MS analysis we found one main metabolite produced at high rates. The structure was identified by its mass spectra. The mass fragmentation indicated hydroxylation in allyl position. After synthesis of the assumed product in a four step reaction, it was characterized as delta-3-Carene-10-ol. There was a clear correlation between the concentration of the metabolite production, incubation time and enzyme concentration, respectively. Kinetic analysis showed that Km and Vmax values for the oxidation of delta-3-Carene by human liver microsomes were 0.39 ,M and 0.2 nmol/min/nmol P450. It is the first time that delta-3-Carene-10-ol is described as human metabolite of delta-3-Carene. [source] Pluronics' influence on pseudomonad biofilm and phenazine productionFEMS MICROBIOLOGY LETTERS, Issue 1 2009Lindsay Housley Abstract Colonization of roots by Pseudomonas chlororaphis O6 (PcO6) involves root surface coverage through surface motility and biofilm formation. Root colonization and the production of antifungal phenazines are important in the ability of the bacterium to protect plants against pathogens. In this in vitro study we report that both biofilm formation and phenazine production are differentially influenced by nutrition and the presence of polyethylene oxide/polypropylene oxide triblock copolymer surfactants (Pluronics). Such surfactants are used for many purposes including agricultural formulations. Four Pluronics differing in molecular weight and in hydrophobic/hydrophilic proportions had distinct effects on biofilm formation and secondary metabolite production, although each increased surface motility, termed swarming, to a similar extent. These findings show that Pluronics had specific metabolic impacts on the bacterium, where both up- and downregulation was achieved depending on the medium and the Pluronic composition. In environmental and agricultural settings, Pluronics may have unanticipated effects on soil microorganisms, while in bioprocessing these effects may be leveraged to regulate metabolite yield. [source] Production of fermentation aroma compounds by Saccharomyces cerevisiae wine yeasts: effects of yeast assimilable nitrogen on two model strainsFEMS YEAST RESEARCH, Issue 7 2008Francisco M. Carrau Abstract The contribution of yeast fermentation metabolites to the aromatic profile of wine is well documented; however, the biotechnological application of this knowledge, apart from strain selection, is still rather limited and often contradictory. Understanding and modeling the relationship between nutrient availability and the production of desirable aroma compounds by different strains must be one of the main objectives in the selection of industrial yeasts for the beverage and food industry. In order to overcome the variability in the composition of grape juices, we have used a chemically defined model medium for studying yeast physiological behavior and metabolite production in response to nitrogen supplementation so as to identify an appropriate yeast assimilable nitrogen level for strain differentiation. At low initial nitrogen concentrations, strain KU1 produced higher quantities of esters and fatty acids whereas M522 produced higher concentrations of isoacids, ,-butyrolactone, higher alcohols and 3-methylthio-1-propanol. We propose that although strains KU1 and M522 have a similar nitrogen consumption profile, they represent useful models for the chemical characterization of wine strains in relation to wine quality. The differential production of aroma compounds by the two strains is discussed in relation to their capacity for nitrogen usage and their impact on winemaking. The results obtained here will help to develop targeted metabolic footprinting methods for the discrimination of industrial yeasts. [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] Expression of 5-lipoxygenase (5-LOX) in T lymphocytesIMMUNOLOGY, Issue 2 2007Jeanne M. Cook-Moreau Summary 5-lipoxygenase (5-LOX) is the key enzyme responsible for the synthesis of the biologically active leukotrienes. Its presence has been reported in cells of the myeloid lineage and B lymphocytes but has not been formally defined in T lymphocytes. In this study, we provide evidence for 5-LOX expression on both transcriptional and translational levels in highly purified peripheral blood T cells as well as in human T lymphoblastoid cell lines (MOLT4 and Jurkat). Messenger RNA (mRNA) of 5-LOX was amplified by conventional reverse transcription,polymerase chain reaction (RT-PCR; MOLT4 and Jurkat cells) and by in situ RT-PCR (T lymphocytes). 5-LOX protein expression was confirmed by Western blot and immunofluorescence studies. 5-LOX was present primarily in the cytoplasm with some nuclear localization and was translocated to the nuclear periphery after culture in a mitosis-supporting medium. Fluorescence-activated cell sorter analysis of different T-lymphocyte populations, including CD4, CD8, CD45RO, CD45RA, T helper type 2, and T-cell receptor-,, and -,, expressing cells, did not identify a differential distribution of the enzyme. Purified peripheral blood T lymphocytes were incapable of synthesizing leukotrienes in the absence of exogenous arachidonic acid. Jurkat cells produced leukotriene C4 and a small amount of leukotriene B4 in response to CD3,CD28 cross-linking. This synthesis was abolished by two inhibitors of leukotriene synthesis, MK-886 and AA-861. The presence of 5-LOX in T lymphocytes but the absence of endogenous lipoxygenase metabolite production compared to Jurkat cells may constitute a fundamental difference between resting peripheral lymphocytes and leukaemic cells. [source] Human Heart Cytosolic Reductases and Anthracycline CardiotoxicityIUBMB LIFE, Issue 1 2001Alvaro Mordente Abstract Anthracyclines are a class of antitumor drugs widely used for the treatment of a variety of malignancy, including leukemias, lymphomas, sarcomas, and carcinomas. Different mechanisms have been proposed for anthracycline antitumor effects including freeradical generation, DNA intercalation/binding, activation of signaling pathways, inhibition of topoisomerase II and apoptosis. A life-threatening form of cardiomyopathy hampers the clinical use of anthracyclines. According to the prevailing hypothesis, anthracyclines injure the heart by generating damaging free radicals through iron-catalyzed redox cycling. Although the "iron and freeradical hypothesis" can explain some aspects of anthracycline acute toxicity, it is nonetheless disappointing when referred to chronic cardiomyopathy. An alternative hypothesis implicates C-13 alcohol metabolites of anthracyclines as mediators of myocardial contractile dysfunction ("metabolite hypothesis"). Hydroxy metabolites are formed upon two-electron reduction of the C-13 carbonyl group in the side chain of anthracyclines by cytosolic NADPH-dependent reductases. Anthracycline alcohol metabolites can affect myocardial energy metabolism, ionic gradients, and Ca 2+ movements, ultimately impairing cardiac contraction and relaxation. In addition, alcohol metabolites can impair cardiac intracellular iron handling and homeostasis, by delocalizing iron from the [4Fe-4S] cluster of cytoplasmic aconitase. Chronic cardiotoxicity induced by C-13 alcohol metabolite might be primed by oxidative stress generated by anthracycline redox cycling ("unifying hypothesis"). Putative cardioprotective strategies should be aimed at decreasing C-13 alcohol metabolite production by means of efficient inhibitors of anthracycline reductases, as short-chain coenzyme Q analogs and chalcones that compete with anthracyclines for the enzyme active site, or by developing novel anthracyclines less susceptible to reductive metabolism. [source] Host-derived media used as a predictor for low abundant, in planta metabolite production from necrotrophic fungiJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2006D.P. Overy Abstract Aims:,Penicillium ser. Corymbifera strains were assayed on a variety of media and from infected Allium cepa tissues to evaluate the stimulation and in planta prediction of low abundance metabolites. Methods and Results:, Stimulated production of corymbiferones and the corymbiferan lactones were observed for Penicillium albocoremium, Penicillium allii, Penicillium hirsutum, Penicillium hordei and Penicillium venetum strains cultured on tissue media. Target metabolites were sporadically detected from strains cultured on common laboratory media (CYA, MEA and YES). Up to a 376 times increase in corymbiferone and corymbiferan lactone production was observed when culture extracts from CYA and A. cepa agar were compared by high pressure liquid chromatography with ultraviolet and mass spectrometry (LC-UV-MS). The novel metabolite corymbiferone B was purified and structure elucidated from a P. allii/A. cepa tissue medium extract. In planta expression of low abundance, target metabolites were confirmed from infected A. cepa tissue extracts by LC-UV-MS. Conclusions:, Secondary metabolite production was directly dependent and influenced by media conditions, resulting in the stimulated production of low abundance metabolites on host-derived media. Significance and Impact of the Study:, The use of macerated host tissue media can be applied in vitro to predict in planta expression of low abundance metabolites and aid in metabolite origin annotation during in planta metabolomic investigations at the host/pathogen interface. [source] Gluconic acid production by Aspergillus terreusLETTERS IN APPLIED MICROBIOLOGY, Issue 3 2010C. Dowdells Abstract Aim:,Aspergillus terreus produces itaconic acid at low pH but lovastatin and other secondary metabolites at higher pH in the fermentation. The utilization of glucose as a carbon substrate was investigated for secondary metabolite production by A. terreus. Methods and Results:, With a starting pH of 6·5, glucose was rapidly metabolized to gluconic acid by the wild-type strain and by transformants harbouring Aspergillus niger genes encoding 6-phosphofructo-1-kinases with superior kinetic and regulatory properties for bioproduction of metabolites from glucose. On exhaustion of the glucose in batch fermentations, the accumulated gluconic acid was utilized as a carbon source. Conclusions:, A novel pathway of glucose catabolism was demonstrated in A. terreus, a species whose wild type is, without any strain development, capable of producing gluconic acid at high molar conversion efficiency (up to 0·7 mol mol,1 glucose consumed). Significance and Impact of the Study:,Aspergillus terreus is a potential novel producer organism for gluconic acid, a compound with many uses as a bulk chemical. With a new knowledge of glucose catabolism by A. terreus, fermentation strategies for secondary metabolite production can be devised with glucose feeding using feedback regulation by pH. [source] Ridogrel, a dual thromboxane synthase inhibitor and receptor antagonist: anti-inflammatory profile in inflammatory bowel diseaseALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 6 2000Carty Background: Thromboxanes, prostaglandins, reactive oxygen metabolites and pro-inflammatory cytokines are produced in excess in inflammatory bowel disease. Preliminary reports suggest that ridogrel, a thromboxane synthesis inhibitor and receptor blocker, may have therapeutic benefits in ulcerative colitis. Aims: To investigate the anti-inflammatory profile of ridogrel. Methods: The effects of ridogrel on the production of eicosanoids, reactive oxygen metabolites and cytokines by cultured inflamed colorectal mucosal biopsies were made using ELISA and chemiluminescence, reactive oxygen metabolite generation in a cell-free system, and platelet activation using flow cytometry. The effects of oral ridogrel on mucosal release of eicosanoids in two patients with active ulcerative colitis were assessed using rectal dialysis. Results: Ridogrel significantly reduced the release of thromboxane B2, but not prostaglandin E2 or tumour necrosis factor-,, from biopsies (P < 0.01 for 10 ,M ridogrel). Ridogrel showed no direct antioxidant activity but significantly reduced reactive oxygen metabolite production from cultured biopsies (P < 0.01 for 10 ,M ridogrel). Platelet activation in vitro was inhibited by ridogrel (P , 0.05 for , 10 ,M ridogrel). Mean rectal mucosal thromboxane B2 release was reduced to 86% of pre-treatment levels in two patients treated with oral ridogrel. Conclusions: Its inhibition of mucosal production of thromboxane B2, reactive oxygen metabolites, and of platelet activation, suggests that ridogrel could have a therapeutic role in inflammatory bowel disease. [source] Ex situ cultivation of Aplysinaaerophoba close to in situ conditions: ecological, biochemical and histological aspectsMARINE ECOLOGY, Issue 2 2008Anne Klöppel Abstract Sponges provide the largest number of biologically active natural products known from the marine environment and continue to be a very well studied phylum of marine fauna. The Mediterranean sponge Aplysina aerophoba accumulates brominated isoxazoline alkaloids such as Aplysinamisin-1, Aerophobin-2, Isofistularin-3 and the biotransformation product Aeroplysinin-1, which possesses, for example, antibiotic and cytotoxic properties. Until now, it is still being discussed which organisms , the sponge itself or associated microorganisms , are responsible for metabolite production. For cultivating Aplysina individuals under ex situ conditions, we surveyed relevant ecological factors in situ and controlled them in our aquarium system. We maintained A. aerophoba for more than 9 months and analysed changes of metabolite content and composition, microbial association as well as morphology in situ and ex situ under different light exposure. Although sponges showed slight reduction during maintenance, ex situ cultivation similar to in situ conditions provides a promising method to keep sponges and obtain their bioactive metabolites. [source] Deciphering regulatory mechanisms for secondary metabolite production in the myxobacterium Sorangium cellulosum So ce56MOLECULAR MICROBIOLOGY, Issue 6 2007Shwan Rachid Summary Sorangium cellulosum strains produce approximately 50% of the biologically active secondary metabolites known from myxobacteria. These metabolites include several compounds of biotechnological importance such as the epothilones and chivosazols, which, respectively, stabilize the tubulin and actin skeletons of eukaryotic cells. S. cellulosum is characterized by its slow growth rate, and natural products are typically produced in low yield. In this study, biomagnetic bead separation of promoter-binding proteins and subsequent inactivation experiments were employed to identify the chivosazol regulator, ChiR, as a positive regulator of chivosazol biosynthesis in the genome-sequenced strain So ce56. Overexpression of chiR under the control of T7A1 promoter in a merodiploid mutant resulted in fivefold overproduction of chivosazol in a kinetic shake flask experiment, and 2.5-fold overproduction by fermentation. Using quantitative reverse transcription PCR and gel shift experiments employing heterologously expressed ChiR, we have shown that transcription of the chivosazol biosynthetic genes (chiA,chiF) is directly controlled by this protein. In addition, we have demonstrated that ChiR serves as a pleiotropic regulator in S. cellulosum, because mutant strains lack the ability to develop into regular fruiting bodies. [source] Complementary action of jasmonic acid on salicylic acid in mediating fungal elicitor-induced flavonol glycoside accumulation of Ginkgo biloba cellsPLANT CELL & ENVIRONMENT, Issue 8 2009MAOJUN XU ABSTRACT The antagonistic action between jasmonic acid (JA) and salicylic acid (SA) in plant defence responses has been well documented. However, their relationship in secondary metabolite production is largely unknown. Here, we report that PB90, a protein elicitor from Phytophthora boehmeriae, triggers JA generation, SA accumulation and flavonol glycoside production of Ginkgo biloba cells. JA inhibitors suppress not only PB90-triggered JA generation, but also the elicitor-induced flavonol glycoside production. However, the elicitor can still enhance flavonol glycoside production even though the JA generation is totally inhibited. Over-expression of SA hydrolase gene NahG not only abolishes SA accumulation, but also suppresses the elicitor-induced flavonol glycoside production when JA signalling is inhibited. Interestingly, expression of NahG does not inhibit the elicitor-induced flavonol glycoside accumulation in the absence of JA inhibitors. Moreover, JA levels are significantly enhanced when SA accumulation is impaired in the transgenic cells. Together, the data suggest that both JA and SA are involved in PB90-induced flavonol glycoside production. Furthermore, we demonstrate that JA signalling might be enhanced to substitute for SA to mediate the elicitor-induced flavonol glycoside accumulation when SA signalling is impaired, which reveals an unusual complementary relationship between JA and SA in mediating plant secondary metabolite production. [source] Comparative analysis of gene expression on mRNA and protein level during development of Streptomyces cultures by using singular value decompositionPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 21 2007Jiri Vohradsky Dr. Abstract This paper describes a comparative systems level analysis of the developmental proteome and transcriptome in the model antibiotic-producing eubacterium Streptomyces coelicolor, cultured on different media. The analysis formulates expression as the superposition of effects of regulatory networks and biological processes which can be identified using singular value decomposition (SVD) of a data matrix formed by time series measurements of expression of individual genes throughout the cell cycle of the bacterium. SVD produces linearly orthogonal factors, each of which can represent an independent system behavior defined by a linear combination of the genes/proteins highly correlated with the corresponding factor. By using SVD of the developmental time series of gene expression, as measured by both protein and RNA levels, we show that on the highest level of control (representing the basic kinetic behavior of the population), the results are identical, regardless of the type of experiment or cultivation method. The results show that this approach is capable of identifying basic regulatory processes independent of the environment in which the organism lives. It also shows that these processes are manifested equally on protein and RNA levels. Biological interpretation of the correlation of the genes and proteins with significant eigenprofiles (representing the highest level kinetic behavior of protein and/or RNA synthesis) revealed their association with metabolic processes, stress responses, starvation, and secondary metabolite production. [source] Secondary metabolite production by the fungal pathogen Eutypa lata: Analysis of extracts from grapevine cultures and detection of those metabolites in plantaAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2 2006RICHARD LARDNER Eutypa dieback of grapevines is caused by the fungal pathogen Eutypa lata and reduces vineyard longevity worldwide. Early detection could reduce losses due to this disease, so our aim was to identify acetylenic phenol metabolites of E. lata that could prove suitable as chemical markers in an early diagnostic test for the pathogen. Accordingly, secondary metabolite production by 30 isolates of E. lata grown on media derived from canes of three grapevine cultivars was analysed using HPLC. Six metabolites, namely eutypinol, methyl eutypinol, eulatachromene, eutypine, 2- iso -propenyl-5-formylbenzofuran and eulatinol, were detected in culture filtrates. Most abundant were eutypinol and methyl eutypinol, produced by 97 and 83% of isolates, respectively. There was no apparent correlation between secondary metabolite production on media containing milled canes from the three cultivars of grapevine, and the field tolerance of these same cultivars to Eutypa dieback. When various other fungi commonly isolated from grapevine trunks in Australia were grown on milled cane, no secondary metabolites characteristic of E. lata were detected, suggesting such compounds are specific to E. lata. To examine the detection of secondary metabolites in planta, micropropagated grapevine plantlets were treated with purified or crude culture filtrates from nine isolates of E. lata grown on malt yeast broth. Various secondary metabolites were identified in treated plantlets, however, no single compound was detected consistently. Eutypinol was detected in micropropagated grapevine plantlets inoculated with mycelium of E. lata, however, no metabolites were detected in the sap of vines which had been artificially inoculated with the pathogen. [source] Production of indole diterpenes by Aspergillus alliaceusBIOTECHNOLOGY & BIOENGINEERING, Issue 5 2006B. Junker Abstract Production of two related indole diterpenes (differing by a dimethyl leucine side chain) by Aspergillus alliaceus was improved through several pilot scale fermentations. Media were optimized through focus primarily on initial increases, as well as mid-cycle additions, of carbon and nitrogen sources. Fermentation conditions were improved by varying ventilation conditions using various combinations of air flowrate and back-pressure set points. Production improvements were quantified based on total indole diterpene concentration as well as the ratio of the major-to-minor by-product components. Those changes with a positive substantial impact primarily on total indole diterpene concentration included early cycle glycerol shots and enhanced ventilation conditions (high air flowrate, low back-pressure). Those changes with a significant impact primarily on ratio included higher initial cerelose, soybean oil, monosodium glutamate, tryptophan, or ammonium sulfate concentrations, higher broth pH, and enhanced ventilation conditions. A few changes (higher initial glycerol and monosodium glutamate concentrations) resulted in less notable and desirable titer or ratio changes when implemented individually, but they were adopted to more fully realize the impact of other improvements or to simplify processing. Overall, total indole diterpene titers were improved at the 600 L pilot scale from 125,175 mg/L with a ratio of about 2.1 to 200,260 mg/L with a ratio of about 3.3,4.5. Thus, the ability to optimize total indole diterpene titer and/or ratio readily exists for secondary metabolite production using Aspergillus cultures. © 2006 Wiley Periodicals, Inc. [source] Effect of the plant peptide regulator, phytosulfokine-,, on the growth and Taxol production from Taxus sp. suspension culturesBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2006Beum Jun Kim Abstract Phytosulfokine-, (PSK-,) is a small plant peptide (5 amino acids) that displays characteristics typically associated with animal peptide hormones. PSK-, was originally isolated based on its mitogenic activity with plant cultures; it has been reported to increase production of tropane alkaloids from Atropa belladonna, although its general influence on secondary metabolite production is unknown. The studies reported in this article were initiated to evaluate the effects of PSK-, supplementation on production of TaxolÔ (paclitaxel) from plant cell cultures of Taxus sp. particularly when methyl jasmonate (MeJA) is added as an elicitor of secondary metabolism. The response to PSK-, supplementation was cell line dependent. Taxus cuspidata P93AF showed no statistically significant response to PSK-, supplementation while Taxus canadensis C93AD and T. cuspidata PO93X displayed a concentration-dependent response (up to 100 nM PSK-, added in first 24 h of culture) with a decrease in initial growth rate, an increase in cell density (dry weight/fresh weight), and increased Taxol production. More remarkably with T. canadensis (C93AD), a very strong synergistic response of PSK-, (100 nM) and methyl jasmonate (MeJA, 100 µM) elicitation was observed, resulting in Taxol level of 35.3,±,2.1 mg/L or 1.83,±,0.02 mg Taxol/g dry cell weight achieved at day 21, a level of approximately 10-fold higher than for either treatment by itself. Although the level of Taxol production achieved is not remarkable, this synergistic treatment was able to partially revive taxane production in cultures that have lost productivity due to extended time (over 10 years) in continuous subculture. © 2006 Wiley Periodicals, Inc. [source] A novel three-stage light irradiation strategy in the submerged fermentation of medicinal Mushroom Ganoderma lucidum for the efficient production of ganoderic acid and Ganoderma polysaccharidesBIOTECHNOLOGY PROGRESS, Issue 6 2008Wei Zhang Abstract A novel three-stage light irradiation strategy in the submerged fermentation of medicinal mushroom Ganoderma lucidum for the efficient production of bioactive metabolites ganoderic acid (GA) and Ganoderma polysaccharides was developed. Significance of light quality, i.e., blue light (390,500 nm, ,max = 470 nm), red light (560,700 nm, ,max = 625 nm), and white light (400,740 nm, ,max = 550 nm), was studied at first. Interestingly, there was a gradual decrease trend of GA content after the culture of day 2 when the maximal GA content was obtained, while GA content decreased slowly under white light irradiation after day 6. The dark environment was favorable to the specific GA biosynthesis (i.e., GA content) before day 6, and after that the optimum was white light irradiation. A relatively lower irradiation density of white light (i.e., 0.94 and 2.82 W/m2) was beneficial for the specific GA biosynthesis before day 6, while GA content was higher under higher irradiation density of white light (i.e., 4.70 and 9.40 W/m2) at the later-stage of cultivation. 4.70 W/m2 white light irradiation culture was the best from the viewpoint of GA accumulation. Therefore, a two-stage light irradiation strategy by combing the first 2 days dark culture with the following 4.70 W/m2 white light irradiation culture was developed. The highest GA production in the two-stage culture was 276.0 ± 12.5 mg/L, which was increased by 19% compared to 4.70 W/m2 white light irradiation culture (i.e., 232.4 ± 15.8 mg/L) and by 178% compared to the dark culture (i.e., 99.4 ± 1.0 mg/L). Although there still existed a gradual decrease trend of GA content after day 2 when the maximal GA content was obtained in the two-stage culture. Following three-stage light irradiation strategy was further demonstrated in order to turn around the sharp decrease of GA content after day 2. The first-stage was the 2-day dark culture; the second-stage was the following six-day 0.94 W/m2 white light irradiation culture, and the third-stage was 4.70 W/m2 white light irradiation culture until the end of fermentation. During the three-stage culture of G. lucidum, the gradual decrease trend of GA content after day 2 was turned around, which suggested that 0.94 W/m2 white light irradiation was beneficial for the metabolic flux towards the GA biosynthesis. The maximal GA content of 3.1 ± 0.1 mg/100 mg DW was obtained, which was higher by 41% compared to the two-stage culture. The maximal GA production (i.e., 466.3 ± 24.1 mg/L) and productivity (i.e., 38.9 mg/L per day) in the three-stage culture were 69 and 101% higher than those obtained in the two-stage culture. This is the first report investigating the significance of light irradiation on the medicinal mushroom submerged fermentation. Such work is very helpful to other mushroom fermentations for useful metabolite production. [source] Alterations in Taxol Production in Plant Cell Culture via Manipulation of the Phenylalanine Ammonia Lyase PathwayBIOTECHNOLOGY PROGRESS, Issue 6 2002Michelle C. Brincat One approach to increasing secondary metabolite production in plant cell culture is to manipulate metabolic pathways to utilize more resources toward production of one desired compound or class of compounds, such as diverting carbon flux from competing secondary pathways. Since phenylalanine provides both the phenylisoserine side chain and the benzoyl moiety at C-2 of Taxol, we speculated that blockage of the phenylpropanoid pathway might divert phenylalanine into Taxol biosynthesis. We used specific enzyme inhibitors to target the first enzyme in the phenylpropanoid pathway, phenylalanine ammonia lyase (PAL), the critical control point for conversion of l -phenylalanine to trans -cinnamic acid. Cinnamic acid acted quickly in reducing PAL activity by 40,50%, without affecting total protein levels, but it generally inhibited the taxane pathway, reducing Taxol by 90% of control levels. Of the taxanes produced, 13-acetyl-9-dihydro-baccatin III and 9-dihydrobaccatin III doubled as a percentage of total taxanes in C93AD and CO93P cells treated with 0.20 and 0.25 mM cinnamic acid, when all other taxanes were lowered. The PAL inhibitor ,-aminooxyacetic acid (AOA) almost entirely shut down Taxol production at both 0.5 and 1.5 mM, whereas l -,-aminooxy-,-phenylpropionic acid (AOPP) had the opposite effect, slightly enhancing Taxol production at 1 ,M but having no effect at 10 ,M. The discrepancy in the effectiveness of AOA and AOPP and the lack of effect with addition of phenylalanine or benzoic acid derivatives further indicates that the impact of cinnamic acid on Taxol is related not to its effect on PAL but rather to a specific effect on the taxane pathway. On the basis of these results, a less direct route for inhibiting the phenylpropanoid pathway may be required to avoid unwanted side effects and potentially enhance Taxol production. [source] Investigation by solid-phase microextraction and gas chromatography/mass spectrometry of secondary metabolites in lichens deposited on stone monumentsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 6 2003Francesco De Angelis Lichens are ubiquitous organisms formed by symbiotic associations of fungal hyphas and algae that also grow under often extreme environmental conditions. They produce secondary metabolites, the so-called lichen substances, whose structural characterization can give an important contribution to lichen taxonomy. Lichens are also widely employed as biomonitors of atmospheric pollution; being epiphyte organisms they tend, in fact, to accumulate exogenous compounds. Moreover, it could be questioned if the environmental stress alters their secondary metabolites production. Therefore, a new strategy for the analysis of the organic substances absorbed or metabolized by lichens has been developed. This method exploits the dry solid-phase microextraction (SPME) headspace technique coupled with gas chromatography/mass spectrometry (GC/MS). Lichens coating the stone surfaces of monuments, located in small towns between high mountains and far away from urban environments, have been investigated. In the field of cultural heritage, this study can contribute to the knowledge of the state of conservation of outdoor exposed historical monuments. Copyright © 2003 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||||||||