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Reverse Phase HPLC (reverse + phase_hplc)
Selected AbstractsDetection of orange juice adulteration by tangelo juice using multivariate analysis of polymethoxylated flavones and carotenoidsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 4 2002Geoffrey G Pan Abstract Reverse phase HPLC has been applied to quantify levels of polymethoxylated flavones and carotenoids in orange and tangelo juices. Lower levels of sinensetin and tetramethyl- o -scutellarein and higher levels of heptamethoxyflavone and tangeretin relative to nobiletin indicated the addition of tangelo to orange juice. ,-Cryptoxanthin and its esters, identified by positive ion electrospray mass spectrometry, were present in larger amounts relative to ,-carotene in tangelo than in orange juice. Using canonical discriminant analysis, the addition of 100,g,kg,1 tangelo to orange juice can be detected. © 2002 Society of Chemical Industry [source] Lysozyme as Pathogen-Recognition Protein in the Hemolymph of Galleria mellonellaENTOMOLOGICAL RESEARCH, Issue 3 2003In Hee LEE ABSTRACT Recognition of invading micro-organisms into hemolymph is a pivotal event for triggering diverse immune mechanisms in insects. It has been known that this recognition was mediated by the binding of hemolymph proteins to pattern-molecules on the cell surface of microbes. Recently, I found that the lysozyme in the G. mellonella hemolymph has binding affinity to cell-walls of Gram (-), (±) bacteria and fungus (Candida albicans). After the hemolymph was incubated with heat-killed microbes and treated with acidic buffer containing high concentration of NaCl, several plasma proteins detached from microbes were detected by reverse phase HPLC and SDS-PAGE analyses. Of binding proteins, it was assumed that the major one might be a lysozyme, which was previously characterized in the G. mellonella hemolymph. Furthermore immunoblot analysis performed with antiserum to G. mellonella lysozyme revealed that it was a lysozyme. [source] Analysis of the role of bacterial endospore cortex structure in resistance properties and demonstration of its conservation amongst speciesJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2001A. Atrih Aims: The aim of this work was to compare the chemical structure of the spore cortex of a range of species, and to determine any correlation between cortex structure and spore resistance properties. Methods and Results: The fine chemical structure of the cortex of Bacillus subtilis, Bacillus megaterium, Bacillus cereus and Clostridium botulinum was examined by muropeptide analysis using reverse phase HPLC. There is a conserved basic structure between peptidoglycan of these species, with the only difference being the level of de -N -acetylation of an amino sugar. In order to determine if an alteration in cortex structure correlates with heat resistance properties, the peptidoglycan structure and properties of B. subtilis spores prepared under different conditions were compared. Peptidoglycan from spores prepared in Nutrient Broth (NB) showed reduction in single L -alanine substituted muramic acid to only 13·9% compared with 20·6% in CCY-grown spores. NB-prepared spores are also unstable, with 161-fold less heat resistance (60 min, 85°C) and 43 times less Mn2+ content than CCY-grown spores. Addition of MnCl2 to NB led to a peptidoglycan profile similar to CCY-grown spores, sevenfold more heat resistance (60 min, 85°C) and an 86-fold increase in Mn2+ content. Addition of CCY salts to NB led all parameters to be comparable with CCY-grown spore levels. Conclusions: It has been shown that peptidoglycan structure is conserved in four spore-forming bacteria. Also, spore heat resistance is multifactorial and cannot be accounted for by any single parameter. Significance and Impact of the Study: Endospores made by diverse species most likely have common mechanisms of heat resistance. However, the molecular basis for their resistance remains elusive. [source] Synthesis of tritium- and deuterium-labeled budesonideJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 1 2008Bachir Latli Abstract Tritium-labeled budesonide was prepared by the selective reduction of a double bond in the butenylenedioxy side chain using carrier-free tritium and palladium on carbon as a catalyst in absolute ethanol. Although the reduction gave a mixture of the desired product and the expected byproducts resulting from over reduction of the other double bonds in ring A, the desired tritium-labeled budesonide was easily isolated by reverse phase HPLC and with specific activity of 54,Ci/mmol. [D8]-budesonide was prepared from 16,-hydroxyprednisolone and D8 -butyraldehyde in 1,4-dioxane in the presence of perchloric acid. The isotopic enrichment was found to be more than 99,atom% D. Copyright © 2008 John Wiley & Sons, Ltd. [source] Mutations on N -terminal region of Taiwan cobra phospholipase A2 result in structurally distorted effectsJOURNAL OF PEPTIDE SCIENCE, Issue 8 2008Yi-Ling Chiou Abstract In the present study, three Taiwan cobra PLA2 variants were prepared by adding an extra N -terminal Met, substituting Asn-1 by Met or deleting the N -terminal heptapeptide. Recombinant PLA2 mutants were expressed in Escherichia coli (E. coli), and purified to homogeneity by reverse phase HPLC. Fluorescence measurement showed that the hydrophobic character of the catalytic site, the microenvironment of Trp residues and energy transfer from excited Trp to 8-anilinonaphthalene sulfonate (ANS) were affected by N -terminal mutations. An alteration in the structural flexibility of the active site was noted with the mutants lacking the N -terminal heptapeptide or with an extra N -terminal Met added as evidenced by the inability of the two variants to bind with Ba2+. Moreover, modification of Lys residues and energy transfer within the protein-ANS complex revealed that the Ca2+ -induced change in the global structure of PLA2 was different from that in N -terminal variants. Together with the fact that an ,activation network' connects the N -terminus with the active site, our data suggest that mutagenesis on the N -terminal region affects directly the fine structure of the catalytic site, which subsequently transmits its influence in altering the structure outside the active site of PLA2. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd. [source] Quantification of polyphenols with potential antioxidant properties in wines using reverse phase HPLCJOURNAL OF SEPARATION SCIENCE, JSS, Issue 12 2008Neuza Paixão Abstract A RP-HPLC method with photodiode array detection (DAD) was developed to separate, identify and quantify simultaneously the most representative phenolic compounds present in Madeira and Canary Islands wines. The optimized chromatographic method was carefully validated in terms of linearity, precision, accuracy and sensitivity. A high repeatability and a good stability of phenolics retention times (< 3%) were obtained, as well as relative peak area. Also high recoveries were achieved, over 80.3%. Polyphenols calibration curves showed a good linearity (r2 >0.994) within test ranges. Detection limits ranged between 0.03 and 11.5 ,g/mL for the different polyphenols. A good repeatability was obtained, with intra-day variations less than 7.9%. The described method was successfully applied to quantify several polyphenols in 26 samples of different kinds of wine (red, rosé and white wines) from Madeira and Canary Islands. Gallic acid was by far the most predominant acid. It represents more than 65% of all phenolics, followed by p -coumaric and caffeic acids. The major flavonoid found in Madeira wines was trans -resveratrol. In some wines, (,)-epicatechin was also found in highest amount. Canary wines were shown to be rich in gallic, caffeic and p -coumaric acids and quercetin. [source] Bioactivity of falcarinol and the influenceof processing and storage on its content in carrots (Daucus carota L)JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2003Susanne L Hansen Abstract The concentration-dependent activity of the polyacetylene falcarinol ((9Z)-heptadeca-1,9-dien-4,6-diyn-3-ol), isolated from carrots, was investigated in a bioassay with primary mammary epithelial cells in collagen gels and compared with that of ,-carotene, the orange pigment in carrots. Falcarinol showed biphasic activity, having stimulatory effects between 0.01 and 0.05 µg ml,1 and inhibitory effects between 1 and 10 µg ml,1, whereas ,-carotene showed no effect in the concentration range 0.001,100 µg ml,1. The results are discussed in relation to the health-promoting effects of carrots and related vegetables. Falcarinol was quantified in the carrot cultivars Bolero, Rodelika and Fancy by analytical reverse phase HPLC, subjected to various processing and storage conditions in order to study how long-term storage, blanching, freezing and boiling influence the content of falcarinol. Long-term storage of raw carrot cubes (1 cm3) reduced the falcarinol content by almost 35%. A similar reduction was found in steam-blanched carrot cubes (1 cm3). Long-term storage at ,24 °C of steam blanched carrot cubes did not reduce the falcarinol content further. A reduction of almost 70% in the falcarinol content was found in carrot pieces boiled in water for 12 min compared with raw carrots. Copyright © 2003 Society of Chemical Industry [source] | |||||||||||||