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Different Compounds (different + compound)
Selected AbstractsCarboxylic multi-walled carbon nanotubes as immobilized stationary phase in capillary electrochromatography,ELECTROPHORESIS, Issue 18 2008Lorena Sombra Abstract Carboxylic multi-walled carbon nanotubes (c-MWNT) have been immobilized into a fused-silica capillary for capillary electrochromatography. The c-MWNT were successfully incorporated after the silanization and coupling with glutaraldehyde on the inner surface of the capillary. The electrochromatographic features of the c-MWNT immobilized stationary phase have been evaluated for the analysis of different compounds of pharmaceutical interest. The results indicated high electrochromatographic resolution, good capillary efficiency and retention factors. In addition, highly reproducible results between runs, days and capillaries were obtained. [source] Application of Exchangeable Biochemical Reactors with Oxidase-Catalase-Co-immobilizates and Immobilized Microorganisms in a Microfluidic Chip-CalorimeterENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 5 2008M. Leifheit Abstract Several methods for the quantitative detection of different compounds, e.g., L -amino acids, sugars or alcohols in liquid media were developed by application of an automatic measuring unit including a fluid chip-calorimeter FCC-21. For this purpose, enzymes were immobilized covalently on the inner and outer surface of CPG (controlled porous glass)-spherules with an outer diameter of 100,,m and filled into a micro flow-through reaction chamber (VR = 20,,L). The design of the measuring cell allows for easy insertion into the calorimeter device of a stored series of comfortably pre-fabricated measuring cells. These cells can be filled with different enzyme immobilizates. Different oxidases were used and co-immobilized with catalase for the improvement of the detection sensitivity. A signal amplification could be achieved up to a factor of 3.5 with this configuration. ,- D -glucose, ethanol and L -lysine could be detected in a range of 0.25,1.75,mM using glucose oxidase, alcohol oxidase and lysine oxidase. The group of oxidases in combination with the enzymatic catalysis of the intermediate H2O2 allows the quantitative detection of a large number of analytes. A good measurement and storage stability could be achieved for several weeks by this immobilization method. In addition to enzyme-based detection reactions, it was shown that living microorganisms can be immobilized in the reaction chamber. Thus, the system can be used as a whole-cell biosensor. The quantitative detection of phenol in the range of 10,100,,M could be performed using the actinomycete Rhodococcus sp. immobilized on glass beads by means of embedding into polymers. [source] Bioaccumulation and biotransformation of arsenic in the Mediterranean polychaete Sabella spallanzanii experimental observationsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2007Alessandra Notti Abstract The Mediterranean fan worm Sabella spallanzanii is characterized by elevated basal levels of arsenic in branchial crowns (>1,000 ,g/g) and an unusual prevalence of dimethylarsinic acid (DMA), a relatively toxic compound with a possible antipredatory role. The aim of this work was to obtain further insights on the capability of this polychaete to accumulate arsenic from different compounds and to operate biotransformation reactions. Laboratory exposures to arsenate (AsV), dimethylarsinic acid (DMA), trimethylarsine (TMA), and arsenobetaine (AsB) revealed significant differences among tissues and kind of experiments. The highest increases of arsenic content were observed in branchial crowns of organisms treated with arsenate, which can enter the cell through the phosphate carrier system; lower variations were measured with DMA and TMA, while not-significant changes of total As occurred after treatments with AsB. In body tissues, exposure to AsV, DMA, and TMA confirmed a progressively lower accumulation of total arsenic, while a marked increase was caused by AsB. Obtained results suggested that accumulated arsenic could be chemically transformed, thus explaining the elevated basal levels of DMA typical of S. spallanzanii; during all the experiments, DMA was the most accumulated molecule, suggesting that this species possesses the enzymatic pathways for methylation and demethylation reactions of inorganic and trimethylated arsenicals. Only arsenobetaine was not converted into DMA, which would confirm a microbial pathway for degradation for this molecule, particularly important in body tissues of S. spallanzanii for the presence of bacteria associated to digestive tracts. Overall, the present study suggests future investigations on the biological role of arsenic and DMA in S. spallanzanii as a potential adaptive mechanism against predation in more vulnerable tissues. [source] Degradation of chlorpyrifos, fenamiphos, and chlorothalonil alone and in combination and their effects on soil microbial activityENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2002Brajesh Kumar Singh Abstract The effects of repeated application and of combinations of pesticides on their degradation rates in soil and on some soil microbial properties were studied. Repeated application of chlorpyrifos did not modify its degradation rate, whereas repeated applications of fenamiphos and chlorothalonil suppressed their own rates of degradation. When applied in combination, the presence of chlorothalonil reduced the degradation rate of both chlorpyrifos and fenamiphos, and the half-life of chlorothalonil was extended in the presence of chlorpyrifos. The dynamics of residues of the major metabolites of the different compounds were also affected by the pesticide combinations and, particularly, by the presence of chlorothalonil. The measured soil microbial parameters (enzyme activities and total microbial biomass) were stable in the pesticide-free control soils throughout the 90-d incubation period, but they were all adversely affected by the presence of chlorothalonil in the soil. The effects from fenamiphos or chlorpyrifos on the soil microbial characteristics were either very small or insignificant. [source] The variation of antioxidant activities and chemical composition of essential oils of Teucrium orientale L. var. orientale during harvesting stagesFLAVOUR AND FRAGRANCE JOURNAL, Issue 5 2004Ali Yildirim Abstract The aerial parts of Teucrium orientale L. var. orientale were collected at the budding, ,owering and vegetative stages. In the each stage, essential oils were obtained by hydrodistillation and steam distillation. The chemical compositions of the essential oils were analysed by GC and GC,MS; 43 different compounds were determined in total, and more than 96% of the essential oils were identi,ed by GC and GC,MS. They contain mainly linalool, , -caryophyllene, 3-octanol, phytol, , -bourbonene and germacrene D. Among the steam distillation oils, the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was found at the budding stage and the lowest at the vegetative stage. At all stages, the DPPH radical scavenging activities of hydrodistillation oils were markedly lower than those of steam distillation oils. Steam distillation oils of the budding and ,owering stages showed the highest antioxidant activities. However, steam distillation oils of the vegetative stage in two doses (200 and 400 µg) did not show antioxidant activities (p > 0.05, between these and control). None of the hydrodistillation oils showed detectable antioxidant activity. In contrast, in the presence of 400 µg hydrodistillation oils of ,owering stage, prooxidant activity was found in the linoleic acid emulsion. Copyright © 2004 John Wiley & Sons, Ltd. [source] The importance of scent and nectar filters in a specialized wasp-pollination systemFUNCTIONAL ECOLOGY, Issue 5 2009Adam Shuttleworth Summary 1.,Plants with open flowers and exposed nectar should attract a wide diversity of flower visitors, yet, for reasons that are not yet well understood, some plants with these ,generalist' floral traits have highly specialized pollination systems. 2.,We investigated this problem in the African milkweed Pachycarpus grandiflorus which has open flowers that produce copious amounts of exposed and concentrated nectar, yet is visited almost exclusively by spider-hunting wasps in the genus Hemipepsis. 3.,These wasps were the only visitors found to consistently carry pollinaria and a cage experiment showed that they are capable of successfully pollinating this plant. Furthermore, experimental hand-pollinations showed that P. grandiflorus is genetically self-incompatible and thus reliant on pollinators for seed set. 4.,We investigated the roles of chemical (nectar and floral scent) and spectral properties in the selective attraction of wasps and the filtering out of other potential flower visitors. Nectar palatability experiments showed that the nectar is unpalatable to honeybees but palatable to the wasps. Choice experiments conducted in the field and using a Y-maze in the laboratory showed that wasps are attracted primarily by scent rather than visual cues. Analysis of scent using Gas Chromatography-Mass Spectrometry showed that these inflorescences produce 36 different compounds, mostly monoterpenes and aliphatics. Analysis of spectral reflectance showed that flowers have similar colouring to the background vegetation. 5.,We conclude that P. grandiflorus is specialized for pollination by Hemipepsis wasps, and in the absence of morphological filters, achieves specialization through unpalatable nectar, cryptic colouring and scent as a selective pollinator attractant. 6.,This study demonstrates that plants whose flowers are not morphologically adapted to exclude particular floral visitors can achieve specialization through non-morphological filters. [source] Divergent Reactivity of 2-Azetidinone-Tethered Allenols with Electrophilic Reagents: Controlled Ring Expansion versus SpirocyclizationADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2010Benito Alcaide Abstract A dual reactivity of 2-azetidinone-tethered allenols may occur by judicious choice of the electrophilic reagents, namely halogenating versus selenating reagents. Using common substrates, structurally different compounds, namely tetramic acids (from N -bromosuccinimide) or spirocyclic seleno-,-lactams (from N -phenylselenophthalimide), can be readily synthesized by these divergent protocols. [source] Computational study of titanium (IV) complexes with organic chromophoresINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 6 2006Ivan Kondov Abstract A computational study of small titanium complexes with the chromophores catechol, alizarin, and coumarin 343 is presented. Employing density functional theory (DFT), the ground-state geometries, energies, and harmonic frequencies of the different compounds are calculated. Furthermore, time-dependent DFT and the configuration interaction singles (CIS) method are used to determine excitation energies and excited-state gradients. Based on these results, the character of the excited states as well as electronic-vibrational coupling strengths are analyzed, and the implications for electron-transfer reactions at dye,semiconductor interfaces are discussed. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 [source] Effect of ATH content on electrical and aging properties of EVA and silicone rubber blends for high voltage insulator compoundJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007M. A. Pradeep Abstract The effect of trihydrated alumina (Al2O3, 3H2O) (ATH) filler in ethylene-vinyl acetate copolymer (EVA) and silicone rubber blends was investigated by performing a series of laboratory experiments to simulate different natural aging conditions. Samples with varying ATH content in a 50-50 blend of EVA and polydimethylsiloxane (PDMS) (silicone rubber, MQ) were tested to investigate the tracking resistance, resistance to UV radiation, corona, heat, and water immersion. Changes in surface resistivity, volume resistivity, and hydrophobic characteristics were evaluated for different compounds having ATH content. These exercises were mainly carried out to optimize the filler level. In immersed condition the water absorption increases with ATH content. The recovery of hydrophobicity, after aging by heat, is appreciable at higher ATH levels, than at lower ATH levels. The tracking and erosion resistance decrease as ATH content increases. When compounds containing different ATH content were subjected to corona treatment, the samples with higher ATH levels exhibited better results. All samples changed their color to a darker shade and there was an increase in the hydrophobicity, when subjected to UV radiation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3505,3516, 2007 [source] Modulation of UDP-glucuronosyltransferase 1A1 in primary human hepatocytes by prototypical inducers,JOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 2 2005Cornelia M. Smith Abstract The primary objective of this study was to evaluate the modulation of UGT1A1 expression in human hepatocytes using prototypical CYP450 inducers. A bank of 16 human livers was utilized to obtain an estimate of the range of UGT1A1 protein expression and catalytic activity. Concentration-dependent changes in UGT1A1 response were evaluated in hepatocyte cultures after treatment with 3-methylchloranthrene, ,-napthoflavone, rifampicin, or phenobarbital. Pharmacodynamic analyses of UGT1A1 expression were conducted and compared to those of CYP450 after treatment with inducers in 2,3 different hepatocyte preparations. Additionally, expression of UGT1A1 mRNA and protein was evaluated in human hepatocytes treated with 14 different compounds known to activate differentially the human pregnane-X-receptor or constitutive androstane receptor. Pharmacodynamic modeling revealed EC50 values statistically significant between UGT1A1 and CYP2B6 after treatment with PB, but not statistically distinguishable between UGT1A1 and CYP's 1A2 or 3A4 after treatment with 3-methylchloranthrene or rifampicin, respectively. UGT1A1 was most responsive to the pregnane-X-receptor-agonists rifampicin, ritonavir, and clotrimazole at the mRNA level and, to a lesser extent, the constitutive androstane receptor-activators, phenobarbital and phenytoin. Pharmacodynamic analyses support a mechanism of coordinate regulation between UGT1A1 and a number of CYP450 enzymes by multiple nuclear receptors. © 2005 Wiley Periodicals, Inc. J Biochem Mol Toxicol 19:96,108, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20058 [source] Self-association and cyclodextrin solubilization of drugsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2002Thorsteinn Loftsson Abstract Phase-solubility diagrams are frequently used to calculate stoichiometry of drug/cyclodextrin complexes. Linear diagrams (AL -type systems) are thought to indicate that the complexes are first order with respect to cyclodextrin and first or higher order with respect to the drug. Positive deviation from linearity (AP -type systems) are thought to indicate formation of complexes that are first order with respect to the drug but second or higher order with respect to cyclodextrin. The phase solubility of several different compounds, i.e., cholesterol, ibuprofen, diflunisal, alprazolam, 17,-estradiol and diethylstilbestrol, and various charged and uncharged cyclodextrins was investigated. Phase-solubility diagrams of cholesterol in aqueous cyclodextrin solutions were all of AP type. However, the phase-solubility diagrams obtained with charged cyclodextrins could not be fitted to complexes of second or higher order with respect to cyclodextrin. The phase-solubility diagrams of ibuprofen and diflunisal were of AL type with slope greater than unity indicating formation of 2:1 drug/cyclodextrin complexes. However, Job's plots and space filling docking studies indicated that 1:1 complexes were formed. These and other observations show that stoichiometry of drug/cyclodextrin complexes cannot be derived from simple phase-solubility studies. Furthermore, the results indicate that drug/cyclodextrin complexes can self-associate to form water-soluble aggregates, which then can further solubilize the drug through non-inclusion complexation. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:2307,2316, 2002 [source] Hydrogen bonding strength,measures based on geometric and topological parameters,JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 1 2004awomir Janusz Grabowski Abstract Different methods of estimating H-bond strength are presented. The studies are based on the results of MP2/6,311++G** calculations and the binding energies are corrected for the basis set superposition error (BSSE). The wavefunctions were further applied to localize bond critical points and ring critical points. The characteristics based on the Bader theory are also applied as indicators and measures of hydrogen bonding. This study compares samples of different compounds. The H-bond strength measures such as the proton,acceptor distance (H···Y), the length of the proton donating bond, the electron density at H···Y bond critical point, the H-bond energy and others are analysed. The case of the intramolecular hydrogen bonding is also analysed, and its special characteristics are given. Copyright © 2003 John Wiley & Sons, Ltd. [source] 1H and 13C NMR study of a series of C-9-substituted 19-norsteroidsJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 1 2002Laurence Dallery Abstract The 1H and 13C NMR spectra of a series of 9-substituted 19-norsteroids were completely assigned using a series of 2D NMR experiments, which included 1H,1H COSY, NOESY and 1H,13C heteronuclear HETCOR and HMQC. For second-order spin systems, chemical shifts and coupling constants were obtained by simulation of the experimental spectrum. Criteria were deduced to characterize the stereochemistry of these different compounds (multiplet pattern of H-8, and variation of chemical shifts). The results allow the easy determination of the configuration at C-9. Conformational changes resulting from the substitution were studied by NMR and molecular modeling calculations (AM1). Copyright © 2001 John Wiley & Sons, Ltd. [source] Molecularly imprinted polymer for selective extraction of endocrine disrupters nonylphenol and its ethoxylated derivates from environmental solidsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 13 2008Laura Núñez Abstract Nonylphenol isomers (NP), linear nonylphenol (4-n-NP) and NP short chain ethoxylated derivates (NPEO1 and NPEO2) are degradation products of nonylphenol polyethoxylates, a worldwide used group of surfactants. All of them are considered endocrine disrupters due to their ability to mimic natural estrogens. In this paper, the preparation and evaluation of several 4-n-NP molecularly imprinted polymers (MIPs) for the selective extraction and clean-up of 4-n-NP, NP, NPEO1 and NPEO2 from complex environmental solid samples is described. Among the different combinations tested, a methacrylic acid-based imprinted polymer prepared in toluene provided the better performance for molecularly imprinted SPE (MISPE). Under optimum MISPE conditions, the polymer was able to selectively retain not only linear NP but also the endocrine disruptors NPEO1, NPEO2 and NP with recoveries ranging from 60 to 100%, depending upon the analyte. The developed MISPE procedure was successfully used for the determination of 4-n-NP, NP, NPEO1 and NPEO2 in sediments and sludge samples at concentration levels according to data reported in the literature for incurred samples. Finally, various sludge samples collected at five different sewage treatment plants from Madrid and commercial sludge for agriculture purposes were analysed. The measured concentrations of the different compounds varied from 3.7 to 107.5 mg/kg depending upon the analyte and the sample. [source] HPLC-DAD in identification and quantification of selected coumarins in crude extracts from plant cultures of Ammi majus and Ruta graveolensJOURNAL OF SEPARATION SCIENCE, JSS, Issue 14 2003Marian Kami Abstract This paper describes a method for the separation and determination of selected coumarins and furanocoumarins in the crude extracts from plant tissue cultures of Ammi majus hairy roots and Ruta graveolens cell suspensions, cultured in vitro, separately or together as co-cultures. The usefulness of the three main components of the eluent used in reversed-phase high performance liquid chromatographic analysis, namely: methanol (MeOH), acetonitrile (ACN), and tetrahydrofuran (THF), and different elution programs, was assessed. In the optimal analytical method a Lichrospher® RP-18e 5-,m column, a THF-MeOH elution gradient, and a UV/VIS DAD detector were used. Due to the presence of many different compounds in the investigated plant extracts, the use of a UV/VIS DAD detector was essential. Coumarins were identified by comparison of their UV spectra with those of the analytical standards, and characterization of peak purity. [source] Control of phlebotomine sandfliesMEDICAL AND VETERINARY ENTOMOLOGY, Issue 1 2003B. Alexander Abstract. Phlebotomine sandflies (Diptera: Psychodidae) transmit many zoonotic diseases (arboviruses, bartonelloses and especially leishmaniases) of importance to human health in at least 80 countries. Measures used to control adult sandflies (Lutzomyia and Phlebotomus) include the use of insecticides (mostly pyrethroids) for residual spraying of dwellings and animal shelters, space-spraying, insecticide-treated nets, impregnated dog-collars and personal protection through application of repellents/insecticides to skin or fabrics. Because the breeding-sites of sandflies are generally unknown, control measures that act specifically against immatures are not feasible, although the effectiveness of a few biological and chemical agents has been demonstrated in laboratory evaluations. Reports of insecticide-resistance refer to only three sandfly species (P. papatasi, P. argentipes and S. shorttii) against DDT in one country (India), although there are reports of DDT-tolerance in several countries. Current knowledge of sandfly susceptibility to various insecticides is summarized. Constraints and advantages of different compounds, formulations and delivery methods for sandfly control under different environmental conditions are discussed. [source] The discovery of antiviral agents: Ten different compounds, ten different stories,MEDICINAL RESEARCH REVIEWS, Issue 6 2008Erik De Clercq Abstract This review article, while autobiographical to some extent, describes the discovery of ten (classes of) antiviral compounds that have made (or just did not make) it to the market for the therapy of viral infections, but each in its own way influenced the landscape of our dealing with virus infections: (i) valaciclovir, (ii) BVDU, (iii) DHPA, (iv) cidofovir, (v) adefovir, (vi) tenofovir, (vii) stavudine, (viii) HEPT, (ix) TIBO, and (x) AMD3100. Successful drug development, as is certainly true for antiviral drugs and exemplified for the acyclic nucleoside phosphonates cidofovir, adefovir and tenofovir, requires patience and perseverance, and a close continuous and dedicated interaction between Chemistry, Biology/Medicine and Industry. © 2008 Wiley Periodicals, Inc. Med Res Rev, 28, No. 6, 929,953, 2008 [source] Nonadiabatic electron,phonon effects in low carrier density superconductorsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 1 2005E. Cappelluti Abstract Different families of unconventional superconductors present a low charge carrier density as a common trait, suggesting that the low charge density can be at the basis of a unifying picture for different superconductors. In the past years we have suggested that the electron,phonon interaction can be responsible for a high- Tc superconducting pairing in a nonadiabatic regime, where nonadiabatic effects are triggered on by the small electronic Fermi energy associated with the low charge density character. A coherent picture of such a framework requires however reconciling the low charge density and the small Fermi energy with a finite metallic character (sizable density of states and large Fermi surfaces). In this paper we investigate the peculiar conditions which are needed to be encountered in order to fulfill these requirements. We discuss the specific case of fullerenes, cuprates and MgB2 alloys by analyzing their specific structural and electronic properties The comparison between these materials and simple instructive models permits to underline the different routes to reconcile these characteristics in different compounds. In cuprates and fullerenes the interplay between small Fermi energies and large Fermi surface is strictly connected with strong electronic correlation effects. A comprehensive understanding of these issues can be useful to the future search for new nonadiabatic high- Tc materials. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Fragrances, male display and mating behaviour of Euglossa hemichlora: a flight cage experimentPHYSIOLOGICAL ENTOMOLOGY, Issue 4 2003Thomas Eltz Abstract., Male euglossine bees (Apidae: Euglossini) collect volatile substances (fragrances) from floral and nonfloral sources and store them in hair-filled cavities in their hind tibiae. Over time, males accumulate large quantities of complex and species-specific blends of fragrances. Various hypotheses have been put forward to explain this behaviour, including the idea that fragrance stores reflect the genetic quality of individual males and have evolved through sexual selection and female choice. Clear support of this hypothesis is lacking, largely because male,female interactions are both rare and difficult to observe in nature. Here, we report a flight cage experiment performed in Panama that permitted mating between virgin females (raised from brood cells) and males captured in the forest at fragrance baits. In the cage, eight individually marked males defended small territories around vertical perch sites and showed a characteristic display, which included a previously unreported ,leg-crossing' movement, possibly related to fragrance release. A total of six copulations and three copulatory attempts by Euglossa hemichlora were observed and partly recorded on video. The copulations, all of which were initiated by the female landing on a male perch, were short (4,10 s) and showed no signs of the transfer of chemical substances from male to female. In some cases, the male hovered directly over the female before descending to mount her, possibly facilitating fragrance evaluation by the female. After the experiment, the contents of the males' hind legs were analysed by gas chromatography-mass spectroscopy, which detected complex mixtures of terpenoids and aromatics (totalling 70 different compounds) dominated by hexahydrofarnesyl acetone, farnesene epoxide, ocimene and p -dimethoxy benzene. Individual total amounts of fragrances were neither related to display activity or perch occupancy by given males, nor to the frequency of matings achieved. Display activity was the only positive correlate of mating frequency. Generally, individuals had uniformly large amounts of stored fragrances in comparison to a previous study of three other species of Panamanian Euglossa. [source] Understanding dendritic cell biology and its role in immunological disorders through proteomic profilingPROTEOMICS - CLINICAL APPLICATIONS, Issue 2 2010Gabriela Bomfim Ferreira Abstract Dendritic cells (DC) have always been present on the bright spot of immune research. They have been extensively studied for the last 35 years, and much is known about their different phenotypes, stimulatory capacity, and role in the immune system. During the last 15 years, great attention has been given to studies on global gene and protein expression profiles during the differentiation and maturation processes of these cells. It is well understood that studying the proteome, together with information on the role of protein post-translational modifications (PTM), will reveal the real dynamics of a living cell. The rapid increase of proteomic studies during the last decade describing the differentiation and maturation process in DCs, as well as modifications brought by the use of different compounds that either increase or decrease their immunogenicity, reflects the importance of understanding the molecular processes behind the functional properties of these cells. In the present review, we will give an overview of proteomic studies focusing on DCs. Thereby we will concentrate on the importance of these studies in understanding DC behavior from a molecular point of view and how these findings have aided in understanding the differences in functional properties of these cells. [source] Rapid detection and characterization of reactive drug metabolites in vitro using several isotope-labeled trapping agents and ultra-performance liquid chromatography/time-of-flight mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 6 2009Timo Rousu Reactive metabolites are believed to be one of the main reasons for unexpected drug-induced toxicity issues, by forming covalent adducts with cell proteins or DNA. Due to their high reactivity and short lifespan they are not directly detected by traditional analytical methods, but are most traditionally analyzed by liquid chromatography/tandem mass spectrometry (LC/MS/MS) after chemical trapping with nucleophilic agents such as glutathione. Here, a simple but very efficient assay was built up for screening reactive drug metabolites, utilizing stable isotope labeled glutathione, potassium cyanide and semicarbazide as trapping agents and highly sensitive ultra-performance liquid chromatography/time-of-flight mass spectrometry (UPLC/TOFMS) as an analytical tool. A group of twelve structurally different compounds was used as a test set, and a large number of trapped metabolites were detected for most of them, including many conjugates not reported previously. Glutathione-trapped metabolites were detected for nine of the twelve test compounds, whereas cyanide-trapped metabolites were found for eight and semicarbazide-trapped for three test compounds. The high mass accuracy of TOFMS provided unambiguous identification of change in molecular formula by formation of a reactive metabolite. In addition, use of a mass defect filter was found to be a usable tool when mining the trapped conjugates from the acquired data. The approach was shown to provide superior detection sensitivity in comparison to traditional methods based on neutral loss or precursor ion scanning with a triple quadrupole mass spectrometer, and clearly more efficient detection and characterization of reactive drug metabolites with a simpler test setup. Copyright © 2009 John Wiley & Sons, Ltd. [source] p53 is dispensable for the induction of apoptosis after inhibition of protein kinase CK2THE PROSTATE, Issue 2 2010Carolin C. Schneider Abstract BACKGROUND Protein kinase CK2 is a ubiquitously expressed heterotetramer consisting of two catalytic ,/,, and two regulatory , subunits. Expression of CK2 is highly elevated in tumor cells where it protects cells from apoptosis. A variety of different compounds were tested as inhibitors of protein kinase CK2 in order to find new therapy strategies. To analyze the role of p53 in the response to CK2 inhibition we used one of the most specific CK2 inhibitors available, TBB, in different prostate cancer cell lines. METHODS We treated prostate cancer cells with the CK2 inhibitor TBB and determined its effect on CK2 activity by an in vitro phosphorylation assay and its effect on viability by an MTT assay. Furthermore, we analyzed changes in the expression of p53 and PARP cleavage by Western Blot analysis. RESULTS Inhibition of CK2 by TBB led to a decrease in cell viability and apoptosis in two cell lines which express wild-type p53 whereas two other cell lines expressing mutant or no p53 failed to show signs of apoptosis. Moreover, cell lines expressing wild-type p53 showed an increase of the amount of p53 and of its transactivation efficiency. However, down-regulation of p53 by RNAi showed that p53 is not necessary for the induction of apoptosis. CONCLUSIONS Wild-type p53 is not necessary for the induction of apoptosis by TBB in prostate cancer cells. Prostate 70: 126,134, 2010. ©2009 Wiley-Liss, Inc. [source] Validation of a GC-MS screening method for anabolizing agents in solid nutritional supplementsBIOMEDICAL CHROMATOGRAPHY, Issue 3 2004W. Van Thuyne Abstract A sensitive and selective method for the screening of 28 different compounds including testosterone and prohormones, nandrolone and prohormones, stanozolol and metandienone in solid nutritional supplements is described and validated. The different substances are extracted from the solid nutritional supplements by liquid,liquid extraction with a mixture of pentane and freshly distilled diethylether (9/1) after dissolving the supplement in NaOH (1 N). The anabolizing agents are derivatized with a mixture of MSTFA/NH4I/ethanethiol (320/1/2), routinely used for the derivatization of anabolic steroids extracted from urine. The TMS-derivatives are analysed by GC-MS in the SIM mode. The limits of detection were in the range from 2 to 40 ng/g. One supplement was analysed with this method and was found to contain several forbidden substances according to IOC doping regulations. All detected compounds, except dihydrotestosterone, could be con,rmed with GC-MS2, proving that the proposed method is suitable for the screening of anabolizing agents in solid nutritional supplements. Copyright © 2004 John Wiley & Sons, Ltd. [source] Characterization of an anandamide degradation system in prostate epithelial PC-3 cells: synthesis of new transporter inhibitors as tools for this studyBRITISH JOURNAL OF PHARMACOLOGY, Issue 3 2004Lidia Ruiz-Llorente The response of anandamide is terminated by a carrier-mediated transport followed by degradation catalyzed by the cloned enzyme fatty acid amidohydrolase (FAAH). In this study, we provide biochemical data showing an anandamide uptake process and the expression of FAAH in human prostate. Anandamide was accumulated in PC-3 cells by a saturable and temperature-dependent process. Kinetic studies of anandamide uptake, determined in the presence of cannabinoid and vanilloid antagonists, revealed apparent parameters of KM=4.7±0.2 ,M and Vmax=3.3±0.3 pmol min,1 (106 cells),1. The accumulation of anandamide was moderately inhibited by previously characterized anandamide transporter inhibitors (AM404, UCM707 and VDM11) but was unaffected by inhibitors of other lipid transport systems (phloretin or verapamil) and moderately affected by the FAAH inhibitor methyl arachidonyl fluorophosphonate. The presence of FAAH in human prostate epithelial PC-3 cells was confirmed by analyzing its expression by Western blot and measuring FAAH activity. To further study the structural requirements of the putative carrier, we synthesized a series of structurally different compounds 1,8 and evaluated their capacity as uptake inhibitors. They showed different inhibitory capacity in PC-3 cells, with (9Z,12Z)- N -(fur-3-ylmethyl)octadeca-9,12-dienamide (4, UCM119) being the most efficacious, with maximal inhibition and IC50 values of 49% and 11.3±0.5 ,M, respectively. In conclusion, PC-3 cells possess a complete inactivation system for anandamide formed by an uptake process and the enzyme FAAH. These results suggest a possible physiological function of anandamide in the prostate, reinforcing the role of endocannabinoid system as a neuroendocrine modulator. British Journal of Pharmacology (2004) 141, 457,467. doi:10.1038/sj.bjp.0705628 [source] High-Throughput Evaluation of Antioxidant and Pro-oxidant Activities of Polyphenols with Thymidine Protection AssaysCHEMBIOCHEM, Issue 7 2005Stéphane Meunier Dr. Abstract A recently reported high-throughput screening strategy has been applied to the rapid selection of new water-soluble antioxidants that display strong protective activities. Based on a competitive immunoassay, a triple-screening procedure was used to evaluate the ability of different compounds to protect thymidine under different oxidative stresses. The pro-oxidant effect of norbadione A in the presence of iron was observed, while some pulvinic acid derivatives proved strongly protective during , radiolysis, UV irradiation, and Fenton-like oxidation. [source] Discovery of New Biocatalysts for the Glycosylation of Terpenoid ScaffoldsCHEMISTRY - A EUROPEAN JOURNAL, Issue 22 2008Lorenzo Caputi Abstract The synthesis of terpenoid glycosides typically uses a chemical strategy since few biocatalysts have been identified that recognise these scaffolds. In this study, a platform of 107 recombinant glycosyltransferases (GTs), comprising the multigene family of small molecule GTs of Arabidopsis thaliana have been screened against a range of model terpenoid acceptors to identify those enzymes with high activity. Twenty-seven GTs are shown to glycosylate a diversity of mono-, sesqui- and diterpenes, such as geraniol, perillyl alcohol, artemisinic acid and retinoic acid. Certain enzymes showing substantial sequence similarity recognise terpenoids containing a primary alcohol, irrespective of the linear or cyclical structure of the scaffold; other GTs glycosylate scaffolds containing secondary and tertiary alcohols; the carboxyl group of other terpenoids also represents a feature that is recognized by GTs previously known to form glucose esters with many different compounds. These data underpin the rapid prediction of potential biocatalysts from GT sequence information. To explore the potential of GTs as biocatalysts, their use for the production of terpenoid glycosides was investigated by using a microbial-based whole-cell biotransformation system capable of regenerating the cofactor, UDP-glucose. A high cell density fermentation system was shown to produce several hundred milligrams of a model terpenoid, geranyl-glucoside. The activities of the GTs are discussed in relation to their substrate recognition and their utility in biotransformations as a complement or alternative to chemical synthesis. [source] | |||||||||||||||||||