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Complex Mixtures (complex + mixture)
Selected AbstractsThe Chemistry of Escapin: Identification and Quantification of the Components in the Complex Mixture Generated by an L -Amino Acid Oxidase in the Defensive Secretion of the Sea Snail Aplysia californicaCHEMISTRY - A EUROPEAN JOURNAL, Issue 7 2009Michiya Kamio Dr. Abstract A complex mixture of products in an enzymatic reaction: Aplysia californica releases amino acid oxidase and its substrate lysine in defensive secretions to produce a mixture of multiple compounds (see figure). Escapin is an L -amino acid oxidase in the ink of a marine snail, the sea hare Aplysia californica, which oxidizes L -lysine (1) to produce a mixture of chemicals which is antipredatory and antimicrobial. The goal of our study was to determine the identity and relative abundance of the constituents of this mixture, using molecules generated enzymatically with escapin and also using products of organic syntheses. We examined this mixture under the natural range of pH values for ink,from ,5 at full strength to ,8 when fully diluted in sea water. The enzymatic reaction likely forms an equilibrium mixture containing the linear form ,-keto-,-aminocaproic acid (2), the cyclic imine ,1 -piperidine-2-carboxylic acid (3), the cyclic enamine ,2 -piperidine-2-carboxylic acid (4), possibly the linear enol 6-amino-2-hydroxy-hex-2-enoic acid (7), the ,-dihydroxy acid 6-amino-2,2-dihydroxy-hexanoic acid (8), and the cyclic aminol 2-hydroxy-piperidine-2-carboxylic acid (9). Using NMR and mass spectroscopy, we show that 3 is the major component of this enzymatic product at any pH, but at more basic conditions, the equilibrium shifts to produce relatively more 4, and at acidic conditions, the equilibrium shifts to produce relatively more 2, 7, and/or 9. Studies of escapin's enzyme kinetics demonstrate that because of the high concentrations of escapin and L -lysine in the ink secretion, millimolar concentrations of 3, H2O2, and ammonia are produced, and also lower concentrations of 2, 4, 7, and 9 as a result. We also show that reactions of this mixture with H2O2 produce ,-aminovaleric acid (5) and ,-valerolactam (6), with 6 being the dominant component under the naturally acidic conditions of ink. Thus, the product of escapin's action on L -lysine contains an equilibrium mixture that is more complex than previously known for any L -amino acid oxidase. [source] Innentitelbild: Paper Spray for Direct Analysis of Complex Mixtures Using Mass Spectrometry (Angew. Chem.ANGEWANDTE CHEMIE, Issue 5 20105/2010) Feuchtes Filterpapier ist Bestandteil einer leistungsfähigen massenspektrometrischen Methode, die G. Cooks, Z. Ouyang et,al. in ihrer Zuschrift auf S.,889,ff. vorstellen. Proben können z.,B. durch Abwischen einer Oberfläche direkt auf das Papier aufgetragen oder aus einer Lösung zugeführt werden. Mögliche Anwendungen ergeben sich für die quantitative Vollblut-Analyse, die mobile Spurenanalytik und die In-situ-Analyse. [source] Paper Spray for Direct Analysis of Complex Mixtures Using Mass Spectrometry,ANGEWANDTE CHEMIE, Issue 5 2010He Wang Komplexe Gemische können für eine massenspektrometrische Analyse von Spurenbestandteilen direkt vom Papier weg ionisiert werden. Vorgeschaltete Trennschritte sind ebenfalls möglich. [source] Analysing the contribution of component cultivars and cultivar combinations to malting quality, yield and disease in complex mixturesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2008Adrian C Newton Abstract BACKGROUND: Mixtures of cereal cultivars grown together generally enhance yield and reduce disease but end-users will not accept them for quality uses. Some combinations with very different quality may be problematic, others complementary. The common origin of Maris Otter for quality in winter barley may enable the benefits of complex mixtures to be exploited without quality compromises. RESULTS: Seven winter barley cultivar monocultures and all their equal proportion mixtures were trialled and data analysed by ANOVA, REML and principal component analyses to determine the contribution of particular varieties or combinations to crop performance. Agronomic yield was positively correlated with component number. Pipkin contributed negatively to thousand grain weight (TGW), but positively to several quality traits; Gleam negatively to the same quality traits but strongly positively to yield; and Melanie combined strong yield and TGW characteristics with neutral quality traits. Interactions in mixtures with Maris Otter, from which most of the cultivars are likely to derive some of their quality traits, were less apparent for quality than for yield. CONCLUSIONS: Complex mixtures gave yield benefits generally without compromising quality, and analysis methods were developed to identify the beneficial or negative effects of component cultivars on malting quality traits, thereby providing data for optimising mixtures design. Copyright © 2008 Society of Chemical Industry [source] Insoluble eggshell matrix proteins , their peptide mapping and partial characterization by capillary electrophoresis and high-performance liquid chromatographyELECTROPHORESIS, Issue 5 2003Ivan Mik Abstract Avian eggshell matrix proteins were studied by two analytical approaches. Peptide mapping was done by trypsin and pepsin followed by collagenase cleavage; analyses were carried out by capillary electrophoresis and reversed-phase high-performance liquid chromatography (HPLC). Comparison of peptide maps obtained by both methods revealed a complex mixture of peptides in the insoluble layers of the eggshell; it was concluded that there are at least three different insoluble protein/peptide layers in the avian eggshell (cuticle, palisade, and mammillary layer). Partial characterization of peptides in each layer was made by HPLC-mass spectrometry analysis. There is an evidence that the eggshell insoluble proteins contain species susceptible to collagenase cleavage, however, the sequences split by this enzyme probably are not those typical for the main triple-helical core of collagenous proteins. It is proposed that the action of collagenase upon eggshell proteins is caused by the side effect of collagenase described previously with synthetic peptides. Some of the proteins present are probably glycosylated. Fatty acid content in the insoluble eggshell layers (after decalcification) was in the range of 2,4% (which reflected both lipid and lipoproteins bound fatty acids). Porphyrin pigments are dominant in the cuticle layer. [source] Comparative in vitro and in vivo genotoxicities of 7H -benzo[c]fluorene, manufactured gas plant residue (MGP), and MGP fractionsENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 3 2004Leslie Cizmas Abstract Manufactured gas plant residue (MGP) is a complex mixture of polycyclic aromatic hydrocarbons (PAHs) that is tumorigenic in the lungs of mice. This study compared the relative genotoxicity of 7H -benzo[c]fluorene (BC), a PAH component of MGP, with MGP and MGP fractions in order to assess the contribution of BC to the genotoxicity of MGP. An MGP sample was separated into seven fractions (F1,F7) using silica gel column chromatography with petroleum ether (PE) followed by PE:acetone (99:1 v/v, then 98:2). PAHs were quantified using gas chromatography/mass spectrometry. An aliquot of F2, the fraction with the highest BC concentration and highest weighted mutagenic activity in Salmonella typhimurium strain TA98, was further separated using silica gel thin-layer chromatography with hexane. The first F2 subfraction, sF2-a, was enriched in BC and coeluting compounds and contained 35,000 ppm BC and 216,109 ppm carcinogenic PAHs (cPAHs, the sum of seven PAHs categorized by the U.S. EPA as class B2 carcinogens). The second F2 subfraction, sF2-b, contained a ninefold lower concentration of BC, with 3,900 ppm BC and 45,216 ppm cPAHs. Female ICR mice received topical application of crude MGP, crude MGP spiked with analytical-grade BC, F2, sF2-a, sF2-b, or analytical-grade BC. DNA adduct levels were analyzed by nuclease P1-enhanced 32P-postlabeling. In lung DNA of mice receiving 0.48 or 3.0 mg/mouse, net total RAL × 109 values were F2, 30.8 and 87.2; sF2-a, 24.8 and 106.7; and sF2-b, 19.6 and 151.0, respectively. Mice dosed with 0.10 mg analytical-grade BC (the mass of BC in 3.0 mg sF2-a) exhibited a net total RAL × 109 value of 7.03 in lung DNA. This was equal to approximately 7% of the total RAL × 109 value produced by 3.0 mg sF2-a. Thus, although BC appears to make an appreciable contribution to pulmonary adduct formation, the results suggest that MGP components other than BC play an important role in lung DNA adduct formation following topical MGP administration. Environ. Mol. Mutagen. 43:159,168, 2004. © 2004 Wiley-Liss, Inc. [source] Degradation of alkanes by bacteriaENVIRONMENTAL MICROBIOLOGY, Issue 10 2009Fernando Rojo Summary Pollution of soil and water environments by crude oil has been, and is still today, an important problem. Crude oil is a complex mixture of thousands of compounds. Among them, alkanes constitute the major fraction. Alkanes are saturated hydrocarbons of different sizes and structures. Although they are chemically very inert, most of them can be efficiently degraded by several microorganisms. This review summarizes current knowledge on how microorganisms degrade alkanes, focusing on the biochemical pathways used and on how the expression of pathway genes is regulated and integrated within cell physiology. [source] Application of toxicity identification evaluation to sediment in a highly contaminated water reservoir in southeastern BrazilENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2006Rosalina P. A. Araújo Abstract Rasgão Reservoir, located close to the Metropolitan region of São Paulo, Brazil, has been analyzed previously, and its sediment was found to be highly toxic, with high levels of metals and polycyclic aromatic hydrocarbons and a complete absence of benthic life. Polychlorinated biphenyls also were present, as was mutagenic activity, detected with the Salmonella/microsome assay. Because of the extremely complex mixture of contaminants in these sediments, a toxicity identification evaluation was performed on the pore water and elutriate using Ceriodaphnia dubia and Vibrio fischeri. Toxicity characterization, identification, and confirmation procedures were performed in one representative sample of the reservoir, and the results indicated that ammonia was the main cause of the toxicity detected with C. dubia in both sediment pore water and elutriate. Chemical analysis corroborated this observation by revealing un-ionized ammonia concentrations as high as 5.14 mg/L in pore water and 2.06 mg/L in elutriate. These high ammonia levels masked possible toxicity caused by other classes of compounds. The toxicity detected with V. fischeri decreased with the time of sample storage and was related to the organic fraction of the pore water and the elutriate, in which compounds such as benzothiazole and nonylphenol were detected. [source] Application of toxicity identification evaluation procedures for characterizing produced water using the tropical mysid, Metamysidopsis insularisENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2004Najila Elias-Samlalsingh Abstract Toxicity identification evaluations (TIEs) were performed on seven produced water (PW) effluents from inland discharge facilities operated in Trinidad and Tobago, a Caribbean tropical country with one of the oldest commercial oil industries in the world. The research was performed to determine the presence and magnitude of toxicity and characterize which toxicants are responsible for observed effects. Marine effluent toxicity characterizations with Metamysidopsis insularis revealed high whole acute toxic-unit response for produced water ranged from 8.1 to >17.0 acute toxic-unit (initial toxicity test) and 5.7 to 1,111 acute toxic-unit (baseline toxicity test). Toxicity test results for all sites except one, which had the highest toxicity, are comparative with similar studies on produced water. The toxicological causality of this complex mixture differed for each PW with nonpolar organics being consistently toxic in all samples. Other potential toxicants contributing to overall toxicity to a much lesser extent were metals, ammonia, and volatile organic compounds. With the use of sodium thiosulfate and filtration manipulations for only PW6 sample, there was very slight reduction in toxicity; therefore, oxidants and filterable materials were not a great contributing factor. Whole effluent toxicity also can be attributed to ionic imbalance and the very stable oil-in-water emulsion that consists of fine oil droplets (less than 0.1,10 ,m with an average diameter of 2.5 ,m). This investigation is the first of its type in Trinidad and demonstrates clearly the applicability of this test method and local test species for evaluating complex effluents in tropical environments. [source] Incidence and impact of axial malformations in larval bullfrogs (Rana catesbeiana) developing in sites polluted by a coal-burning power plantENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2000William A. Hopkins Abstract Amphibian malformations have recently received much attention from the scientific community, but few studies have provided evidence linking environmental pollution to larval amphibian malformations in the field. We document an increased incidence of axial malformations in bullfrog larvae (Rana catesbeiana) inhabiting two sites contaminated with coal combustion wastes. In the polluted sites, 18 and 37% of larvae exhibited lateral curvatures of the spine, whereas zero and 4% of larvae from two reference sites had similar malformations. Larvae from the most heavily polluted site had significantly higher tissue concentrations of potentially toxic trace elements, including As, Cd, Se, Cu, Cr, and V, compared with conspecifics from the reference sites. In addition, malformed larvae from the most contaminated site had decreased swimming speeds compared with those of normal larvae from the same site. We hypothesize that the complex mixture of contaminants produced by coal combustion is responsible for the high incidence of malformations and associated effects on swimming performance. [source] Tocotrienols and cancer: Beyond antioxidant activityEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 4 2007Kalanithi Nesaretnam Abstract The edible oil industry has emerged as an important provider of raw material for the extraction of vitamin,E. Vegetable oils, especially the seed oils, are rich sources of tocopherols. However, in palm oil, vitamin,E occurs as a complex mixture of tocopherols and tocotrienols. Various tocotrienol isomers of vitamin,E in palm oil have been reported to possess interesting biological and physiological properties not generally evident with tocopherol-rich vitamin,E preparations. They include potential blood cholesterol-lowering and cardioprotective effects, more efficient antioxidant activity in biological systems, and possible anti-cancer and neuroprotective effects. With the emergence of palm oil as the largest edible oil in world markets, technology is now available to extract tocotrienol-rich palm vitamin,E. Initiatives in Malaysia to manufacture biodiesel will further generate large amounts of micronutrients, especially tocotrienols, to be available to the nutraceutical and functional food industry. [source] Structural analysis of the lipopolysaccharide from Chlamydophila psittaci strain 6BCFEBS JOURNAL, Issue 18 2000Sabine Rund The lipopolysaccaride of Chlamydophila psittaci 6BC was isolated from tissue culture-grown elementary bodies using a modified phenol/water procedure followed by extraction with phenol/chloroform/light petroleum. Compositional analyses indicated the presence of 3-deoxy- dmanno -oct-2-ulosonic acid, GlcN, organic bound phosphate and fatty acids in a molar ratio of ,,3.3 : 2 : 1.8 : 4.6. Deacylated lipopolysaccharide was obtained after successive microscale treatment with hydrazine and potassium hydroxide, and was then separated by high performance anion-exchange chromatography into two major fractions, the structures of which were determined by 600 MHz NMR spectroscopy as ,-Kdo-(2,8)-,-Kdo-(2,4)-,-Kdo-(2,6)-,- d -GlcpN-(1,6)-,- d -GlcpN 1,4,-bisphosphate and ,-Kdo-(2,4)-[,-Kdo-(2,8)]-,-Kdo-(2,4)-,-Kdo-(2,6)-,- d -GlcpN-(1,6)-,- d -GlcpN 1,4,-bisphosphate. The distribution of fatty acids in lipid A was determined by compositional analyses and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry experiments on lipid A and de-O-acylated lipid A. It was shown that the carbohydrate backbone of lipid A is replaced by a complex mixture of fatty acids, including long-chain and branched (R)-configured 3-hydroxy fatty acids, the latter being exclusively present in an amide linkage. [source] Encapsulation and release of a fluorescent probe, khusimyl dansylate, obtained from vetiver oil by complex coacervationFLAVOUR AND FRAGRANCE JOURNAL, Issue 1 2008A. S. Prata Abstract The essential oil of vetiver [Vetiveria zizanoides (L.) Nash ex. Small] is widely used in the perfume industry, owing to its pleasant, long-lasting, woody aroma. If this substance can be encapsulated in microparticles so that its release can be controlled, the effective duration of its properties should be extended for a much longer period of time. The present study was thus designed to investigate the encapsulation of this vetiver essential oil in microparticles. Since the detection of the effective release of such a complex mixture from these microparticles into the receiving medium can be problematic, an identifiable probe can be released with it to facilitate evaluation of the progression of the release process. Zizanoic acid is one of the compounds found in vetiver oil which depreciates its sensorial quality. This acid was thus extracted and reduced to the corresponding alcohol, khusimol, which was combined with dansyl chloride to form a fluorescent ester, khusimyl dansylate (KD). The vetiver oil and the fluorescent probe were then encapsulated (100:1) in microparticles produced by the complex coacervation of gum Arabic and gelatin. The microparticles showed spherical shape, multinuclear distribution of the core material and high encapsulation efficiency (95%). Two versions of these microparticles, moist and freeze-dried ones, were tested for the release of the KD into an ethanol medium. The moist particles released the whole KD after 5 h, although only 80% of the fluorescent probe was released with the freeze-dried microparticles at that time, probably due to the constriction caused by freeze-drying. The release of the components of vetiver oil, under the same experimental conditions, was followed, in parallel, by gas chromatography and the results obtained were compared and discussed. Copyright © 2007 John Wiley & Sons, Ltd. [source] Composition and antifungal activity of essential oils isolated from Hypericum hyssopifolium and Hypericum heterophyllumFLAVOUR AND FRAGRANCE JOURNAL, Issue 1 2004A. Cakir Abstract The composition of the hydrodistilled essential oils obtained from the aerial parts of Hypericum hyssopifolium subsp. elongatum var. elongatum and H. heterophyllum Vent. were analysed by means of GC and GC,MS, and 66 compounds were determined in total. The oils showed remarkable differences in chemical composition. The oil of H. hyssopifolium, which is rich in monoterpenes, consists primarily of , -pinene (57.3%), , -pinene (9.0%), limonene (6.2%) and , -phellandrene (4.4%). The oil of H. heterophyllum was a complex mixture consisting mainly of sesquiterpenes (72.9% of the total oil). In this oil, isocaryophyllene (17.1%), , -pinene (11.6%), , -cadinene (9.5%), , -muurolene (8.2%), n -decane (5.8%), , -cadinene (5.5%) and , -caryophyllene (4.5%) were found to be major constituents. The two essential oils were tested for antifungal activity using microbial growth inhibition assays in vitro against 10 agricultural pathogenic fungi, which consisted of ,ve Fusarium species (F. oxysporum, F. culmorum, F. sambucinum, F. solani and F. acuminatum) and ,ve anastomosis groups of Rhizoctonia solani (AG-3, AG-4, AG-5, AG-9 and AG-11). In general, the oils showed moderate activity against several fungal species, viz F. acuminatum, AG-5 and AG-11. The most signi,cant results were obtained against AG-11 for H. heterophyllum oil. However, both oils increased the growth of some fungal species. In addition, the antifungal activity of 13 pure compounds identi,ed as major components in the essential oils of the Hypericum species studied were determined using microbial growth inhibition assays against the 10 fungal species mentioned above. Among these compounds, both , -caryophyllene oxide and , -terpineol were inhibitory to the growth of all fungi. Copyright © 2003 John Wiley & Sons, Ltd. [source] The uses and abuses of time: globalization and time arbitrage in India's outsourcing industriesGLOBAL NETWORKS, Issue 1 2009SHEHZAD NADEEM Abstract Globalization has undoubtedly altered our conceptions and experience of time. It has sped up the pace of life and some scholars even suggest that a new temporal order is supplanting ,natural' and pre-existing cycles and rhythms. Yet time is not dissolved in the global circuits of capital. Rather, globalization has brought about a complex mixture of temporal orientations; the workplaces of ,new economy', for example, are traversed by novel and retrograde modes of work pace, rhythm and time-discipline. In this article, I explore the temporal implications of the outsourcing of information technology-based service work to India. Drawing on fieldwork and interviews with workers, managers and executives in the Indian IT and Business Processing Outsourcing industries, I address the following questions: (1) How are corporations using time arbitrage to reap the full benefits of a globally dispersed labour pool? (2) What impacts are these temporal changes having on the health and social lives of Indian workers? For corporations, time arbitrage means increased efficiency and cost-savings. But for workers, it results in long hours, an intense work pace, and temporal displacement. Night-shift employees, such as call centre workers, are particularly vulnerable to such displacement, as manifested in health and safety problems and social alienation. Globalization therefore does not entail the loosening of temporal chains, but their reconfiguration: a combination both rigid and flexible that binds even as it liberates. [source] Cycloaddition Reactions of 7-Benzylidenecycloocta-1,3,5-triene with Ethenetetracarbonitrile and 4-Phenyl-3H -1,2,4-triazole-3,5(4H)-dioneHELVETICA CHIMICA ACTA, Issue 7 2005Philip Clements An (E)/(Z) mixture (3,:,2) of 7-benzylidenecycloocta-1,3,5-triene (5) is obtained when 1-benzylcycloocta-1,3,5,7-tetraene (7), prepared by an improved procedure, is treated with t -BuOK in THF. Alternatively, a ca. 9,:,1 mixture (E)/(Z)- 5 can be prepared in a Wittig reaction involving benzaldehyde and cycloocta-2,4,6-trien-1-ylidenetriphenylphoshorane (9). Treatment of (E)/(Z)- 5 88,:,12 with ethenetetracarbonitrile (TCNE) gave a complex mixture of products, from which seven mono-adducts and two bis-adducts were isolated (Sect.,2.2.1). Of the mono-adducts, four are ,4+,2 adducts: two ((E)- and (Z)-isomers) are derived from valence tautomers of the two isomers of (E)/(Z)- 5, while it is tentatively suggested that the other two (again (E)- and (Z)-isomers) are formed from the intermediacy of a pentadienyl zwitterion (Sect.,2.3). The remaining three mono-adducts, two of which are epimers, are ,8+,2 adducts. It is suggested that they are derived from the intermediacy of homotropylium zwitterions (Sect.,2.3). For the two bis-adducts, it is postulated that they are derived from an initial ,2+,2 cycloaddition involving the homotropylium zwitterions followed by ,4+,2 cycloaddition to the valence tautomer of each of the ,2+,2 cycloadducts. With 4-phenyl-3H -1,2,4-triazole-3,5(4H)-dione (6), (E)/(Z)- 5 91,:,9 yielded two ,4+,2 cycloadducts ((E)- and (Z)-isomers) as well as two epimeric ,8+,2 cycloadducts (Sect.,2.2.2). The intermediacy of pentadienyl (tentative suggestion) and homotropylium zwitterions accounts for the formation of the products (Sect.,2.3). [source] Cigarette smoking, endothelial injury and cardiovascular diseaseINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 4 2000Michael Pittilo Despite the fact that the epidemiological evidence linking cigarette smoking with cardiovascular disease is overwhelming, the precise components of cigarette smoke responsible for this relationship and the mechanisms by which they exert their effect have not yet been elucidated. There are however, some promising pointers as a result of recent developments and this review concentrates on new evidence since earlier reviews of this topic. It is now known that the endothelium has a vastly more important role than was ever thought to be the case a decade ago. Its role in health and disease is increasingly understood, as is the relationship between endothelial injury and the development of atherosclerosis. There is considerable evidence that cigarette smoking can result in both morphological and biochemical disturbances to the endothelium both in vivo and in cell culture systems. Cigarette smoke is a complex mixture and only a few components have been extensively studied. Nicotine and carbon monoxide are much less damaging than is whole smoke. However the free radical components of cigarette smoke have been shown to cause damage in model systems. Further work will be necessary to consolidate the evidence base but the data reported in this review suggest that the free radical components of cigarette smoke may be responsible for the morphological and functional damage to endothelium that has been observed in model systems. [source] Synthesis of 2-amino-4h -thiazolo[5,4- b]indole and characterization of its colored conversion products with protein tyrosine phosphatase inhibitory activityJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 3 2001Jens Breinholt In DMSO-solution 2-amino-4H -thiazolo[5,4- b]indole is converted into a complex mixture of colored products. The three major conversion end-products, of which two are inhibitors of protein tyrosine phos-phatases (PTPs), were isolated by chromatographic methods and their structures characterized by spectro-scopic analysis, including NMR and MS combined with computer assisted structure elucidation, and, finally, confirmed by independent chemical synthesis. Synthesis of 2-amino-4H -thiazolo[5,4- b]indole as well as its N -acetyl derivatives prepared from either oxindole or 2-bromo-1-(2-nitro-phenyl)ethanone is described. [source] Protein purification using chromatography: selection of type, modelling and optimization of operating conditionsJOURNAL OF MOLECULAR RECOGNITION, Issue 2 2009J. A. Asenjo Abstract To achieve a high level of purity in the purification of recombinant proteins for therapeutic or analytical application, it is necessary to use several chromatographic steps. There is a range of techniques available including anion and cation exchange, which can be carried out at different pHs, hydrophobic interaction chromatography, gel filtration and affinity chromatography. In the case of a complex mixture of partially unknown proteins or a clarified cell extract, there are many different routes one can take in order to choose the minimum and most efficient number of purification steps to achieve a desired level of purity (e.g. 98%, 99.5% or 99.9%). This review shows how an initial 'proteomic' characterization of the complex mixture of target protein and protein contaminants can be used to select the most efficient chromatographic separation steps in order to achieve a specific level of purity with a minimum number of steps. The chosen methodology was implemented in a computer- based Expert System. Two algorithms were developed, the first algorithm was used to select the most efficient purification method to separate a protein from its contaminants based on the physicochemical properties of the protein product and the protein contaminants and the second algorithm was used to predict the number and concentration of contaminants after each separation as well as protein product purity. The application of the Expert System approach was experimentally tested and validated with a mixture of four proteins and the experimental validation was also carried out with a supernatant of Bacillus subtilis producing a recombinant , -1,3-glucanase. Once the type of chromatography is chosen, optimization of the operating conditions is essential. Chromatographic elution curves for a three-protein mixture (, -lactoalbumin, ovalbumin and , -lactoglobulin), carried out under different flow rates and ionic strength conditions, were simulated using two different mathematical models. These models were the Plate Model and the more fundamentally based Rate Model. Simulated elution curves were compared with experimental data not used for parameter identification. Deviation between experimental data and the simulated curves using the Plate Model was less than 0.0189 (absorbance units); a slightly higher deviation [0.0252 (absorbance units)] was obtained when the Rate Model was used. In order to optimize operating conditions, a cost function was built that included the effect of the different production stages, namely fermentation, purification and concentration. This cost function was also successfully used for the determination of the fraction of product to be collected (peak cutting) in chromatography. It can be used for protein products with different characteristics and qualities, such as purity and yield, by choosing the appropriate parameters. Copyright © 2008 John Wiley & Sons, Ltd. [source] New insights into the biotransformation and pharmacokinetics of oxaliplatinJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2009Elin Jerremalm Abstract Oxaliplatin is used primarily in the treatment of metastatic colorectal cancer. In this minireview, we discuss potentially important biotransformation pathways in light of its short elimination half-life in vivo. We also highlight new information achieved using a selective analytical technique to measure intact oxaliplatin in pharmacokinetic studies (comprising intravenous, intraperitoneal, and intrahepatic administration) and compare to results obtained by measurements of total platinum. The use of selective analytical techniques is strongly recommended giving kinetic parameters of the parent compound and not only to a complex mixture of platinum containing endogenous compounds. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:3879,3885, 2009 [source] The Biological Responses to Resveratrol and Other Polyphenols From Alcoholic BeveragesALCOHOLISM, Issue 9 2009Lindsay Brown Although excessive consumption of ethanol in alcoholic beverages causes multi-organ damage, moderate consumption, particularly of red wine, is protective against all-cause mortality. These protective effects could be due to one or many components of the complex mixture of bioactive compounds present in red wine including flavonols, monomeric and polymeric flavan-3-ols, highly colored anthocyanins as well as phenolic acids and the stilbene polyphenol, resveratrol. The therapeutic potential of resveratrol, firstly in cancer chemoprevention and then later for cardioprotection, has stimulated many studies on the possible mechanisms of action. Further indications for resveratrol have been developed, including the prevention of age-related disorders such as neurodegenerative diseases, inflammation, diabetes, and cardiovascular disease. These improvements are remarkably similar yet there is an important dichotomy: low doses improve cell survival as in cardio- and neuro-protection yet high doses increase cell death as in cancer treatment. Fewer studies have examined the responses to other components of red wine, but the results have, in general, been similar to resveratrol. If the nonalcoholic constitutents of red wine are to become therapeutic agents, their ability to get to the sites of action needs to be understood. This mini-review summarizes recent studies on the possible mechanisms of action, potential therapeutic uses, and bioavailability of the nonalcoholic constituents of alcoholic beverages, in particular resveratrol and other polyphenols. [source] Copper-coated microsprayer interface for on-line sheathless capillary electrophoresis electrospray mass spectrometry of carbohydratesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 3 2006Alina D. Zamfir Abstract A sturdy home-built sheathless CE/ESI-QTOF-MS system was developed and optimized for carbohydrate analysis. The interface and employed methodology provided a simple analytical solution to laborious CE/MS interfacing methods and to problems in characterization of complex carbohydrate mixtures that require high-resolution separation of the components. The CE/ESI interface, feasible in any MS laboratory, consists of a one-piece CE column having the CE terminus in-laboratory shaped as a microsprayer and coated with copper. The CE microsprayer was inserted into an in-house made stainless steel clenching device and the whole assembly was mounted onto a quadrupole TOF mass spectrometer. The analytical potential of the interface in terms of suitability, microsprayer performance, copper coat durability, ionization efficiency, spray stability, and sensitivity was tested first on a simple mixture of standard saccharides, which were separated, resolved, and detected with high separation efficiency. The approach was next assessed for the screening of a biological sample, a complex mixture of O -glycosylated sialylated amino acids from urine of a patient suffering from Schindler disease. Preliminary data allow this method to be considered as one of general applicability in structural glycobiology and glycomics and easy to be implemented for proteomic surveys as well. [source] ECOSYSTEM DYNAMICS AND POLLUTION EFFECTS IN AN OZARK CAVE STREAM,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 6 2003Gary O. Graening ABSTRACT: Subterranean ecosystems harbor globally rare fauna and important water resources, but ecological processes are poorly understood and are threatened by anthropogenic stresses. Ecosystem analyses were conducted from 1997 to 2000 in Cave Springs Cave, Arkansas, situated in a region of intensive land use, to determine the degree of habitat degradation and viability of endangered fauna. Organic matter budgeting quantified energy flux and documented the dominant input as dissolved organic matter and not gray bat guano (Myotis grisescens). Carbon/nitrogen stable isotope analyses described a trophic web of Ozark cavefish (Amblyopsis rosae) that primarily consumed cave isopods (Caecidotea stiladactyla), which in turn appeared to consume benthic matter originating from a complex mixture of soil, leaf litter, and anthropogenic wastes. Septic leachate, sewage sludge, and cow manure were suspected to augment the food web and were implicated in environmental degradation. Water, sediment, and animal tissue analyses detected excess nutrients, fecal bacteria, and toxic concentrations of metals. Community assemblage may have been altered: sensitive species-grotto salamanders (Typhlotriton spelaeus) and stygobro-mid amphipods,were not detected, while more resilient isopods flourished. Reduction of septic and agricultural waste inputs may be necessary to restore ecosystem dynamics in this cave ecosystem to its former undisturbed condition. [source] Important roles of the hyphenated HPLC-DAD-MS-SPE-NMR technique in metabonomicsMAGNETIC RESONANCE IN CHEMISTRY, Issue S1 2009Huiru Tang Abstract Metabolite identification is a key step for metabonomics study. A fully automated hyphenation of HPLC-diode-array detector (DAD) mass spectrometry (MS) solid phase extraction (SPE),NMR spectroscopy (HPLC-DAD-MS-SPE-NMR) is one of the most efficient methods to determine the structure of a given unknown metabolite in a complex mixture (metabonome) and hence represents one of the most important analytical techniques for the further development of metabonomics. In this review, some recent applications of this technique in identifying novel and trace metabolites in plant extracts and drug metabolism have been discussed. Modification of this hyphenated technique, enabling multiple trappings of strong polar metabolites for biofluids, needs further development. Copyright © 2009 John Wiley & Sons, Ltd. [source] Real-life applications of the MULVADO software package for processing DOSY NMR dataMAGNETIC RESONANCE IN CHEMISTRY, Issue 2 2006R. Huo Abstract MULVADO is a newly developed software package for DOSY NMR data processing, based on multivariate curve resolution (MCR), one of the principal multivariate methods for processing DOSY data. This paper will evaluate this software package by using real-life data of materials used in the printing industry: two data sets from the same ink sample but of different quality. Also a sample of an organic photoconductor and a toner sample are analysed. Compared with the routine DOSY output from monoexponential fitting, one of the single channel algorithms in the commercial Bruker software, MULVADO provides several advantages. The key advantage of MCR is that it overcomes the fluctuation problem (non-consistent diffusion coefficient of the same component). The combination of non-linear regression (NLR) and MCR can yield more accurate resolution of a complex mixture. In addition, the data pre-processing techniques in MULVADO minimise the negative effects of experimental artefacts on the results of the data. In this paper, the challenges for analysing polymer samples and other more complex samples will also be discussed. Copyright © 2005 John Wiley & Sons, Ltd. [source] Techniques for phosphopeptide enrichment prior to analysis by mass spectrometryMASS SPECTROMETRY REVIEWS, Issue 1 2010Jamie D. Dunn Abstract Mass spectrometry is the tool of choice to investigate protein phosphorylation, which plays a vital role in cell regulation and diseases such as cancer. However, low abundances of phosphopeptides and low degrees of phosphorylation typically necessitate isolation and concentration of phosphopeptides prior to MS analysis. This review discusses the enrichment of phosphopeptides with immobilized metal affinity chromatography, reversible covalent binding, and metal oxide affinity chromatography. Capture of phosphopeptides on TiO2 seems especially promising in terms of selectivity and recovery, but the success of all methods depends on careful selection of binding, washing, and elution solutions. Enrichment techniques are complementary, such that a combination of methods greatly enhances the number of phosphopeptides isolated from complex samples. Development of a standard series of phosphopeptides in a highly complex mixture of digested proteins would greatly aid the comparison of different enrichment methods. Phosphopeptide binding to magnetic beads and on-plate isolation prior to MALDI-MS are emerging as convenient methods for purification of small (µL) samples. On-plate enrichment can yield >70% recoveries of phosphopeptides in mixtures of a few digested proteins and can avoid sample-handling steps, but this technique is likely limited to relatively simple samples such as immunoprecipitates. With recent advances in enrichment techniques in hand, MS analysis should provide important insights into phosphorylation pathways. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 29:29,54, 2010 [source] High-performance liquid chromatographic separation and identification of polyphenolic compounds from the infusion of Davilla elliptica St. HillPHYTOCHEMICAL ANALYSIS, Issue 1 2008Clenilson M. Rodrigues Abstract The isolation of polyphenolic compounds from an infusion of the Brazilian plant Davilla elliptica (Dilleniaceae), used as tea by virtue of its digestive properties, is described. An improved preparative HPLC method was used in order to isolate pure polyphenols from the complex mixture. Liquid,liquid extraction and solid-phase extraction were employed to minimise the interference of polymeric compounds and to provide an enriched fraction of the compounds of interest. The identification of the isolated compounds was performed using analytical HPLC as well as direct injection electrospray ionisation ion trap tandem mass spectrometry (ESI-IT-MS/MS). The high flavonoid content suggests that D. elliptica may be a promising source of compounds to produce natural phytomedicines. Copyright © 2007 John Wiley & Sons, Ltd. [source] Fractionation of grape tannins and analysis by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometryPHYTOCHEMICAL ANALYSIS, Issue 4 2003Camille Perret Abstract Polymeric tannins, extracted from grape berries (Gamay variety), were fractionated according to their mean degree of polymerisation (mDP) on a styrene,divinylbenzene phase eluted with a gradient of methanol:chloroform. Increasing the percentage of methanol led to the solubilisation of higher molecular weight tannins. The mean mDP of each collected fraction was determined by acid-catalysed degradation in the presence of a nucleophilic reagent. The fractionation method produced a linear gradient of mDP varying between 1.84 and 19.34. The fractions were partially characterised by matrix assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). The spectra showed a complex mixture of proanthocyanidins and galloylated proanthocyanidins up to 4000,amu. Copyright © 2003 John Wiley & Sons, Ltd. [source] Analgesic, antipyretic and Ulcerogenic properties of an indigenous formulation , KalpaamruthaaPHYTOTHERAPY RESEARCH, Issue 6 2007Rajendran Mythilypriya Abstract A modified indigenous Siddha formulation Kalpaamruthaa (KA), containing Semecarpus anacardium nut milk extract (SA), dried powder of Emblica officinalis (EO) fruit and honey was evaluated for its analgesic, antipyretic and Ulcerogenic properties. Both SA and KA, at a dose of 150 mg/kg b. wt were compared with the standard drug diclofenac sodium. KA exhibited an enhanced effect on all properties compared with that found with sole SA treatment, and is likely to be due to synergistic and additive interactions within the complex mixture of phytochemicals present in KA. Copyright © 2007 John Wiley & Sons, Ltd. [source] The secreted and surface proteomes of the adult stage of the carcinogenic human liver fluke Opisthorchis viverriniPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 5 2010Jason Mulvenna Abstract Infection with the human liver fluke, Opisthorchis viverrini, is a serious public health problem in Thailand, Laos and nearby locations in Southeast Asia. Both experimental and epidemiological evidence strongly implicate liver fluke infection in the etiology of one of the liver cancer subtypes, cholangiocarcinoma (CCA). To identify parasite proteins critical for liver fluke survival and the etiology of CCA, OFFGEL electrophoresis and multiple reaction monitoring were employed to characterize 300 parasite proteins from the O. viverrini excretory/secretory products and, utilizing selective labeling and sequential solubilization, from the host-exposed tegument. The excretory/secretory included a complex mixture of proteins that have been associated with cancers, including proteases of different mechanistic classes and orthologues of mammalian growth factors and anti-apoptotic proteins. Also identified was a cysteine protease inhibitor which, in other helminth pathogens, induces nitric oxide production by macrophages, and, hence may contribute to malignant transformation of inflamed cells. More than 160 tegumental proteins were identified using sequential solubilization of isolated teguments, and a subset of these was localized to the surface membrane of the tegument by labeling living flukes with biotin and confirming surface localization with fluorescence microscopy. These included annexins, which are potential immuno-modulators, and orthologues of the schistosomiasis vaccine antigens Sm29 and tetraspanin-2. Novel roles in pathogenesis were suggested for the tegument,host interface since more than ten surface proteins had no homologues in the public databases. The O. viverrini proteins identified here provide an extensive catalogue of novel leads for research on the pathogenesis of opisthorchiasis and the development of novel interventions for this disease and CCA, as well as providing a scaffold for sequencing the genome of this fluke. [source] | |||||||||||||||||||||||||||||||||||||||||||