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861.
862.
863.
Wolfgang Scherer Prof. Dr. Christoph Hauf Dipl.‐Phys. Manuel Presnitz Dipl.‐Phys. Ernst‐Wilhelm Scheidt Dr. Georg Eickerling Dr. Volker Eyert Dr. Rolf‐Dieter Hoffmann Dr. Ute C. Rodewald Dipl.‐Ing. Adrienne Hammerschmidt Dr. Christian Vogt Dr. Rainer Pöttgen Prof. Dr. 《Angewandte Chemie (International ed. in English)》2010,49(9):1578-1582
864.
Hay‐Yan J. Wang Cheng Bin Liu Hsuan‐Wen Wu Jr Shin Kuo 《Rapid communications in mass spectrometry : RCM》2010,24(14):2057-2064
Stroke, a deleterious cerebrovascular event, is caused by a critical reduction in the blood flow to the brain parenchyma that leads to brain injury and loss of brain functions. The inflammatory responses following ischemia often aggravate the neurological damage. Several pro‐inflammatory mediators released after stroke are closely related to the metabolism of phospholipids. In this study we directly profiled the changes in phospholipids in the infarcted rat cerebral cortex 24 hours after middle cerebral artery occlusion (MCAO) using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). Several phosphatidylcholine (PC) species and sphingomyelin (SM) were significantly decreased after infarction. The cationization pattern of the remaining PCs showed a prominent shift from a mostly potassiated or protonated form to a predominantly sodiated pattern. Stroke also elevated the lysophosphatidylcholines (LPCs) and heme in tissue. The isobaric pairs in PC and LPC classes were resolved by masses through their respective alkali metal adducts in the presence of CsCl. The major fatty acyl LPC species were also structurally confirmed by MALDI‐MS/MS. Overall, the results described the changes in PC and LPC species in the infarcted rat cortex. The elevated tissue levels of LPCs and heme signify the ongoing pathological lipid breakdown and the state of parenchymal inflammation. The elevated LPC level in tissue suggests a means of intervention through lysophospholipid metabolism that could potentially benefit the management of stroke and other acute neurological injuries. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
865.
Eva‐Maria Hein Bertram Bödeker Jürgen Nolte Heiko Hayen 《Rapid communications in mass spectrometry : RCM》2010,24(14):2083-2092
Electrospray ionization mass spectrometry (ESI‐MS) has emerged as an indispensable tool in the field of lipidomics. Despite the growing interest in lipid analysis, there are only a few software tools available for data evaluation, as compared for example to proteomics applications. This makes comprehensive lipid analysis a complex challenge. Thus, a computational tool for harnessing the raw data from liquid chromatography/mass spectrometry (LC/MS) experiments was developed in this study and is available from the authors on request. The Profiler‐Merger‐Viewer tool is a software package for automatic processing of raw‐data from data‐dependent experiments, measured by high‐performance liquid chromatography hyphenated to electrospray ionization hybrid linear ion trap Fourier transform mass spectrometry (FTICR‐MS and Orbitrap) in single and multi‐stage mode. The software contains three parts: processing of the raw data by Profiler for lipid identification, summarizing of replicate measurements by Merger and visualization of all relevant data (chromatograms as well as mass spectra) for validation of the results by Viewer. The tool is easily accessible, since it is implemented in Java and uses Microsoft Excel (XLS) as output format. The motivation was to develop a tool which supports and accelerates the manual data evaluation (identification and relative quantification) significantly but does not make a complete data analysis within a black‐box system. The software's mode of operation, usage and options will be demonstrated on the basis of a lipid extract of baker's yeast (S. cerevisiae). In this study, we focused on three important representatives of lipids: glycerophospholipids, lyso‐glycerophospholipids and free fatty acids. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
866.
Meiling Lu Xing‐Fang Li X. Chris Le Michael Weinfeld Hailin Wang 《Rapid communications in mass spectrometry : RCM》2010,24(11):1523-1532
We describe a method for probing surface‐exposed cysteines in proteins by selective labeling with p‐hydroxymercuribenzoate (PMB) combined with nano‐electrospray ionization mass spectrometric analysis (nanoESI‐MS). The rapid, stoichiometric, and specific labeling by PMB of surface‐exposed cysteines allows for characterization of the accessibility of the cysteines using a single MS analysis. Moreover, by taking advantage of the large mass shift of 321 Da, unique isotopic pattern, and enhanced MS signal of PMB‐labeled cysteine‐containing peptide fragments, the surface‐exposed cysteines in proteins can be accurately identified by peptide mapping. The number and sites of reactive cysteines on the surface of human and rat hemoglobins (hHb and rHb) were identified as examples. Collision‐induced dissociation tandem mass spectrometric (MS/MS) analysis of specific peptides further confirmed the selective labeling of PMB in hHb. The subtle difference between the different cysteine residues in rHb was also evaluated by multiple PMB titrations. The difference between the two cysteines in their environment may partially explain their reaction specificity. Cysteine 125 in the β unit of rHb is exposed on the surface, explaining its reactivity with glutathione. Cysteine 13 in the α subunit of rHb is much less exposed, and is located in a hydrophobic pocket, a conclusion that is consistent with the previous observation of its selective binding with dimethylarsinous acid, a reactive arsenic metabolite. The method is potentially useful for probing cysteines in other biologically important proteins and for studying proteins that are associated with conformational or structural changes induced by denaturing processes, protein modifications, protein‐protein interactions and protein assemblies. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
867.
Zhan Yu Lee Chuin Chen Rosa Erra‐Balsells Hiroshi Nonami Kenzo Hiraoka 《Rapid communications in mass spectrometry : RCM》2010,24(11):1507-1513
Probe electrospray ionization (PESI) is a modified version of the electrospray ionization (ESI), where the capillary for sampling and spraying is replaced by a solid needle. High tolerance to salts and direct ambient sampling are major advantages of PESI compared with conventional ESI. In this study, PESI‐MS was used to monitor some biological and chemical reactions in real‐time, such as acid‐induced protein denaturation, hydrogen/deuterium exchange (HDX) of peptides, and Schiff base formation. By using PESI‐MS, time‐resolved mass spectra and ion chromatograms can be obtained reproducibly. Real‐time PESI‐MS monitoring can give direct and detailed information on each chemical species taking part in reactions, and this is valuable for a better understanding of the whole reaction process and for the optimization of reaction parameters. PESI‐MS can be considered as a potential tool for real‐time reaction monitoring due to its simplicity in instrumental setup, direct sampling with minimum sample preparation and low sample consumption. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
868.
Shu‐Ping Wang Lei Liu Ling‐Ling Wang Peng Jiang Ji‐Quan Zhang Wei‐Dong Zhang Run‐Hui Liu 《Rapid communications in mass spectrometry : RCM》2010,24(11):1641-1652
Based on the serum pharmacochemistry technique and high‐performance liquid chromatography/diode‐array detection (HPLC/DAD) coupled with electrospray tandem mass spectrometry (HPLC/ESI‐MS/MS), a method for screening and analysis of the multiple absorbed bioactive components and metabolites of Jitai tablets (JTT) in orally dosed rat plasma was developed. Plasma was treated by methanol precipitation prior to liquid chromatography, and the separation was carried out on a Symmetry C18 column, with a linear gradient (0.1% formic acid/water/acetonitrile). Mass spectra were acquired in negative and positive ion modes, respectively. As a result, 26 bioactive components originated from JTT and 5 metabolites were tentatively identified in orally dosed rat plasma by comparing their retention times and MS spectra with those of authentic standards and literature data. It is concluded that an effective and reliable analytical method was set up for screening the bioactive components of Chinese herbal medicine, which provided a meaningful basis for further pharmacology and active mechanism research of JTT. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
869.
E. R. Dixon M. S. A. Blackwell M. S. Dhanoa Z. Berryman N. de la Fuente Martinez D. Junquera A. Martinez P. J. Murray H. F. Kemp W. Meier‐Augenstein A. Duffy R. Bol 《Rapid communications in mass spectrometry : RCM》2010,24(5):511-518
Variations in natural abundance of carbon (C) and nitrogen (N) stable isotopes are widely used as tools for many aspects of scientific research. By examining variations in the ratios of heavy to light stable isotopes, information can be obtained as to what physical, chemical and biological processes may be occurring. The spatial heterogeneity of soil δ15N‐ and δ13C‐values across a range of scales and under different land use have been described by a number of researchers and the natural abundances of the C and N stable isotopes in soils have been found to be correlated with many factors including hydrology, topography, land use, vegetation cover and climate. In this study the Latin square sampling +1 (LSS+1) sampling method was compared with a simple grid sampling approach for δ13C and δ15N measurement at the field scale. A set of 144 samples was collected and analysed for δ15N and δ13C from a 12 × 12 grid (in a 1 ha improved grassland field in south‐west England). The dimension of each cell of the grid was approximately 11 × 6 m. The 12 × 12 grid was divided into four 6 × 6 grids and the LSS+1 sampling technique was applied to these and the main 12 × 12 grid for a comparison of sample means and variation. The LSS+1 means from the 12 × 12 grid and the four 6 × 6 grids compared well with the overall grid mean because of the low variation within the field. The LSS+1 strategy (13 samples) generated representative samples from the 12 × 12 grid, and hence would be an acceptable method for sampling similar plots for the measurement of mean isotopic composition. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
870.
Steven J. Granger Roland Bol Wolfram Meier‐Augenstein Melanie J. Leng Helen F. Kemp Tim H. E. Heaton Sue M. White 《Rapid communications in mass spectrometry : RCM》2010,24(5):475-482
Stable isotopes of water have been previously used in catchment studies to separate rain‐event water from pre‐event groundwater. However, there are a lack of studies at the smaller scale looking at the separation of event water from pre‐event water. This is particularly relevant for heavy clay soil systems through which the movement of water is uncertain but is thought to be rainwater‐dominated. The data presented here were collected at a rural site in the south‐west of England. The historic rainfall at the site was isotopically varied but similar to the global meteoric water line, with annual weighted means of ?37‰ for δ2H and ?5.7‰ for δ18O and with no seasonal variation. Drainage was sampled from the inter‐flow (surface runoff + lateral through‐flow) and drain‐flow (55 cm deep mole drains) pathways of two 1 ha lysimeters during two rainfall events, which had δ2H values of ?68‰ and ?92‰, respectively. The δ2H values of the lysimeter drainage water suggest that there was no contribution of event water during the first, small discharge (Q) event; however, the second larger event did show isotopic variation in δ2H values negatively related to Q indicating that rainwater was contributing to Q. A hydrograph separation indicated that only 49–58% of the inter‐flow and 18–25% of the drain‐flow consisted of event water. This was surprising given that these soil types are considered retentive of soil water. More work is needed on heavy clay soils to understand better the nature of water movement from these systems. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献