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https://www.readbyqxmd.com/read/29792807/micelles-protect-intact-metallo-supramolecular-block-copolymer-complexes-from-solution-to-gas-phase-during-electrospray-ionization
#1
Kai Hung Huang, Tsung-Han Tu, Shi-Cheng Wang, Yi-Tsu Chan, Cheng-Chih Hsu
Supramolecular diblock copolymers using metal-ligand coordination can be synthesized under ambient conditions by delicate design of the end groups of the homopolymer chains. However, mass spectrometric analysis of such metallo-supramolecular copolymers is challenging. One of the reasons is the nonpolarity of the polymer chains, making it hard to disperse the complexes in electrospray ionization (ESI)-friendly environments. The other difficulty is the noncovalent nature of such copolymers, which is easily disrupted during the ionization...
May 24, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/29790753/target-decoy-based-false-discovery-rate-estimation-for-large-scale-metabolite-identification
#2
Xusheng Wang, Drew R Jones, Timothy I Shaw, Ji-Hoon Cho, Yuanyuan Wang, Haiyan Tan, Boer Xie, Suiping Zhou, Yuxin Li, Junmin Peng
Metabolite identification is a crucial step in mass spectrometry (MS)-based metabolomics. However, it is still challenging to assess the confidence of assigned metabolites. In this study, we report a novel method for estimating false discovery rate (FDR) of metabolite assignment with a target-decoy strategy, in which the decoys are generated through violating the octet rule of chemistry by adding small odd numbers of hydrogen atoms. The target-decoy strategy was integrated into JUMPm, an automated metabolite identification pipeline for large-scale MS analysis, and was also evaluated with two other metabolomics tools, mzMatch and mzMine 2...
May 23, 2018: Journal of Proteome Research
https://www.readbyqxmd.com/read/29790532/brimstone-chemistry-under-laser-light-assists-mass-spectrometric-detection-and-imaging-the-distribution-of-arsenic-in-minerals
#3
Swapnil Lal, Zhaoyu Zheng, Julius Pavlov, Athula B Attygalle
Singly charged As2n+1 ion clusters (n = 2-11) were generated from elemental arsenic by negative-ion laser-ablation mass spectrometry. The overall abundance of the gaseous As ions generated upon laser irradiation was enhanced nearly a hundred times when As-bearing samples were admixed with sulfur. However, sulfur does not act purely as an inert matrix: irradiating arsenic-sulfur mixtures revealed a novel pathway to generate and detect a series of [AsSn]- clusters (n = 2-6). Intriguingly, the spectra recorded from As2O3, NaAsO2, Na3AsO4, cacodylic acid and 3-amino-4-hydroxyphenylarsonic acid together with sulfur as the matrix were remarkably similar to that acquired from an elemental arsenic and sulfur mixture...
May 23, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29790367/are-hydroethidine-based-probes-reliable-for-ros-detection
#4
Yi Xiao, David Meierhofer
Detection and quantification of the highly reactive and short lived superoxide (O·2-) can be challenging. Here, we present a new mass spectrometry (MS)-based method to detect and quantify O·2- using three fluorogenic hydroethidine probes: HE, mito-HE, and HPr+, which measure cytosolic, mitochondrial and extracellular O·2-, respectively. The probes and their oxidation products were simultaneously quantified by applying multiple reaction monitoring (MRM) with mass spectrometry that allowed the specific measurement of ROS distribution within the cell...
May 23, 2018: Antioxidants & Redox Signaling
https://www.readbyqxmd.com/read/29790113/structural-studies-of-fucosylated-n-glycans-by-ion-mobility-mass-spectrometry-and-collision-induced-fragmentation-of-negative-ions
#5
David J Harvey, Weston B Struwe
There is considerable potential for the use of ion mobility mass spectrometry in structural glycobiology due in large part to the gas-phase separation attributes not typically observed by orthogonal methods. Here, we evaluate the capability of traveling wave ion mobility combined with negative ion collision-induced dissociation to provide structural information on N-linked glycans containing multiple fucose residues forming the Lewisx and Lewisy epitopes. These epitopes are involved in processes such as cell-cell recognition and are important as cancer biomarkers...
May 22, 2018: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/29790112/an-automated-high-throughput-method-for-interpreting-the-tandem-mass-spectra-of-glycosaminoglycans
#6
Jiana Duan, I Jonathan Amster
The biological interactions between glycosaminoglycans (GAGs) and other biomolecules are heavily influenced by structural features of the glycan. The structure of GAGs can be assigned using tandem mass spectrometry (MS2 ), but analysis of these data, to date, requires manually interpretation, a slow process that presents a bottleneck to the broader deployment of this approach to solving biologically relevant problems. Automated interpretation remains a challenge, as GAG biosynthesis is not template-driven, and therefore, one cannot predict structures from genomic data, as is done with proteins...
May 22, 2018: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/29789477/ms-ms-guided-isolation-of-clarinoside-a-new-anti-inflammatory-pentalogin-derivative
#7
Coralie Audoin, Adam Zampalégré, Natacha Blanchet, Alexandre Giuliani, Emmanuel Roulland, Olivier Laprévote, Grégory Genta-Jouve
Re-investigation of the chemical composition of the annual plant Mitracarpus scaber Zucc. led to the identification of clarinoside, a new pentalogin derivative containing a rare quinovose moiety, and the known compound harounoside. While the planar structure was fully determined using tandem mass spectrometry (MS) and quantum mechanics (QM) calculations, the tridimensional structure was unravelled after isolation and NMR analysis. The absolute configuration was assigned by comparison of experimental and theoretical synchrotron radiation circular dichroism spectra...
May 22, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29789190/use-of-matrix-assisted-laser-desorption-ionization-time-of-flight-mass-spectrometry-to-identify-mlst-clade-4-clostridium-difficile-isolates
#8
Jing-Wei Cheng, Chang Liu, Timothy Kudinha, Meng Xiao, Shu-Ying Yu, Chun-Xia Yang, Ming Wei, Guo-Wei Liang, Dong-Hua Shao, Fanrong Kong, Zhao-Hui Tong, Ying-Chun Xu
Clostridium difficile is the leading cause of health care-associated infections. Previous studies suggest that C. difficile MLST clade 4 strains with higher drug resistance rates constitute the major clone spreading in China. Thus development of a rapid and accurate typing method for these strains is needed to monitor the epidemiology of this clone and to guide clinical treatment. A total of 160 non-duplicate C. difficile isolates recovered from three large teaching hospitals in Beijing were studied. All the 41 clade 4 C...
April 26, 2018: Diagnostic Microbiology and Infectious Disease
https://www.readbyqxmd.com/read/29787230/wavefunction-engineering-in-cdse-pbs-core-shell-quantum-dots
#9
Brian M Wieliczka, Alexey Leonid Kaledin, William E Buhro, Richard A Loomis
The synthesis of epitaxial CdSe/PbS core/shell quantum dots (QDs) is reported. The PbS shell grows in a rock salt structure on the zinc blende CdSe core, thereby creating a crystal structure mismatch through additive growth. Absorption and photoluminescence (PL) band edge features shift to lower energies with increasing shell thickness, but remain above the CdSe bulk band gap. Nevertheless, the profiles of the absorption spectra vary with shell growth, indicating that the overlap of the electron and hole wavefunctions is changing significantly...
May 22, 2018: ACS Nano
https://www.readbyqxmd.com/read/29784595/comparative-proteome-analysis-of-the-capsule-from-patients-with-frozen-shoulder
#10
Yoshihiro Hagiwara, Masaru Mori, Kenji Kanazawa, Akira Ando, Yutaka Yabe, Masashi Koide, Takuya Sekiguchi, Nobuyuki Itaya, Masahiro Tsuchiya, Eiji Itoi
BACKGROUND: The etiology of frozen shoulder (FS) is unclear. Accordingly, this study used a label-free quantitative shotgun proteomic approach to elucidate the pathogenesis of FS based on protein expression levels. METHODS: Tissue samples from the rotator interval (RI), middle glenohumeral ligament (MGHL), and anterior-inferior glenohumeral ligament (IGHL) were collected from 12 FSs with severe stiffness and 7 shoulders with a rotator cuff tear (RCT) as controls...
May 18, 2018: Journal of Shoulder and Elbow Surgery
https://www.readbyqxmd.com/read/29783146/gas-chromatographic-mass-spectrometric-characterization-of-thebaol-an-opium-constituent-and-its-structural-analogs
#11
Levan Megutnishvili, Nino Todua, Stephen Stein, Anzor Mikaia
A GC-MS method is described for the characterization of thebaol, a component of opium poppy. The method includes preliminary sample derivatization to TMS, TBDMS, TFA, PFP and HFB substituted products. Fragmentation of resulting derivatives is unique under electron ionization, and proceeds via consecutive loss of two radicals that violate the "even-electron rule". Peaks of [M-2CH3 ]+. and [M-C4 H9 -CH3 ]+. ions show maximum intensities in the spectra of trimethyl- and tert-butyldimethylsilyl-thebaols...
May 18, 2018: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/29778887/biological-potential-of-oxo-vanadium-salicylediene-amino-acid-complexes-as-cytotoxic-antimicrobial-antioxidant-and-dna-interaction
#12
Mohamed Shaker S Adam, Hany Elsawy
New series of oxo-vanadium N-salicyledieneamino acid Schiff base complexes are synthesized and characterized. They are synthesized from the reaction of sodium salicylaldehyde-5-sulfonate, some amino acids, alanine (VOHL1), leucine (VOHL2) or glycine (VOHL3) in an aqueous media, and leucine (VOHLpy1) or tryptophan (VOHLpy2) in pyridine with vanadyl acetylacetonate. The complexes are characterized by EA, TGA, IR, UV-Visible and mass spectra, conductivity and magnetic measurements. The biological activity of the VO-complexes shows that VOHL1, VOHL2 and VOHL3 exhibit anti-proliferative effect and may be used as anticancer drugs...
May 4, 2018: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/29778575/tanzawaic-acid-derivatives-from-freshwater-sediment-derived-fungus-penicillium-sp
#13
Miada F Abdelwahab, Mostafa A Fouad, Mohamed S Kamel, Ferhat Can Özkaya, Rainer Kalscheuer, Werner E G Müller, Wenhan Lin, Zhen Liu, Weaam Ebrahim, Georgios Daletos, Peter Proksch
Chemical investigation of a freshwater sediment-derived fungus, Penicillium sp. (S1a1), led to the isolation of three new tanzawaic acid derivatives, including penitanzchroman (1), tanzawaic acids Y (2) and Z (3), along with six known tanzawaic acid analogues (4-9), three known isochromans (10-12) and two known benzoquinones (13 and 14). The structures of the new compounds were established based on high-resolution mass spectrometry, and detailed analysis of one- and two-dimensional NMR spectroscopy. The relative configuration of the new compounds was assigned on the basis of NMR spectroscopic data including ROESY spectra...
May 17, 2018: Fitoterapia
https://www.readbyqxmd.com/read/29777934/specific-stability-indicating-spectrofluorimetric-method-for-determination-of-ledipasvir-in-the-presence-of-its-confirmed-degradation-products-application-in-human-plasma
#14
Ramadan Ali, Adel A Marzouk, Reda A Abdelhameid, Mahmoud A Omar
A rapid and specific spectrofluorimetric method with higher sensitivity was developed for determination of ledipasvir (LDS) in tablets and human plasma. The proposed method relies on hydrogen bonding formations between the hydroxyl groups of polyoxyethylene 50 stearate and LDS, causing significant enhancement of its native fluorescence. The fluorescence intensity was measured at 430 nm after excitation at 340 nm. The fluorescence-concentration plot was rectilinear over the range 1-400 ng mL-1 with detection and quantification limits of 0...
May 16, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/29777870/profiling-modifications-for-glioblastoma-proteome-using-ultra-tolerant-database-search-are-the-peptide-mass-shifts-biologically-relevant-or-chemically-induced
#15
Irina A Tarasova, Peter M Chumakov, Sergei A Moshkovskii, Mikhail V Gorshkov
Peptide mass shifts were profiled using ultra-tolerant database search strategy for shotgun proteomics data sets of human glioblastoma cell lines demonstrating strong response to the type I interferon (IFNα-2b) treatment. The main objective of this profiling was revealing the cell response to IFN treatment at the level of protein modifications. To achieve this objective, statistically significant changes in peptide mass shift profiles between IFN treated and untreated glioblastoma samples were analyzed. Detailed analysis of MS/MS spectra allowed further interpretation of the observed mass shifts and differentiation between post-translational and artifact modifications...
May 16, 2018: Journal of Proteomics
https://www.readbyqxmd.com/read/29775970/anti-inflammatory-flavanones-and-flavanols-from-the-roots-of-pongamia-pinnata
#16
Ran Wen, Haining Lv, Yong Jiang, Pengfei Tu
A phytochemical study of the roots of Pongamia pinnata afforded 29 flavanones and flavanols, including 7 previously undescribed compounds. The structures of the isolated compounds were determined by 1D and 2D NMR and mass spectroscopy data. The absolute configurations of the compounds were assigned via analysis of the specific rotations and electronic circular dichroism spectra, application of Mosher's method, and by comparing the calculated and experimental electronic circular dichroism spectra. The isolates were evaluated for their inhibitory effects on nitric oxide production in lipopolysaccharide-stimulated BV-2 microglial cells...
May 18, 2018: Planta Medica
https://www.readbyqxmd.com/read/29774958/effect-of-trapping-method-on-species-identification-of-phlebotomine-sandflies-by-maldi-tof-ms-protein-profiling
#17
P Halada, K Hlavackova, J Risueño, E Berriatua, P Volf, V Dvorak
Sandflies (Diptera: Psychodidae) (Newstead, 1911) are blood-feeding insects that transmit human pathogens including Leishmania (Trypanosomatida: Trypanosomatidae) parasites, causative agents of the leishmaniases. To elucidate Leishmania transmission cycles, conclusive identification of vector species is essential. Molecular approaches including matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) protein profiling have recently emerged to complement morphological identification...
May 18, 2018: Medical and Veterinary Entomology
https://www.readbyqxmd.com/read/29774740/searchgui-a-highly-adaptable-common-interface-for-proteomics-search-and-de-novo-engines
#18
Harald Barsnes, Marc Vaudel
Mass spectrometry-based proteomics has become the standard approach for identifying and quantifying proteins. A vital step consists of analyzing experimentally generated mass spectra to identify the underlying peptide sequences, for later mapping to the originating proteins. We here present the latest developments to SearchGUI, a common open source interface for the most frequently used freely available proteomics search and de novo engines, which has evolved into a central component in numerous bioinformatics workflows...
May 18, 2018: Journal of Proteome Research
https://www.readbyqxmd.com/read/29774329/syntheses-and-studies-of-electron-energy-transfer-of-new-dyads-based-on-an-unsymmetrical-perylene-diimide-incorporating-chelating-1-10-phenanthroline-and-its-corresponding-square-planar-complexes-with-dichloroplatinum-ii-and-dichloropalladium-ii
#19
Sebile Işık Büyükekşi, Ahmet Karatay, Nursel Acar, Betül Küçüköz, Ayhan Elmali, Abdurrahman Şengül
Perylene diimides (PDIs) are among the most versatile and functional dyes for supramolecular structures displaying characteristic high absorptions and photo-luminescence properties as the prerequisite for optoelectronic thin film devices. Despite intense investigations into these semi-conducting and electro-active materials, details of their electronic structure are still under examination. In particular, non-planar twisted PDIs as an electron acceptor is a promising model system for efficient charge generation and transport processes...
May 18, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29772817/computational-convolution-of-seldi-data-for-the-diagnosis-of-alzheimer-s-disease
#20
Destiny E O Anyaiwe, Gautam B Singh, George D Wilson, Timothy J Geddes
Alzheimer's disease is rapidly becoming an endemic for people over the age of 65. A vital path towards reversing this ominous trend is the building of reliable diagnostic devices for definite and early diagnoses in lieu of the longitudinal, usually inconclusive and non-generalize-able methods currently in use. In this article, we present a survey of methods for mining pools of mass spectrometer saliva data in relation to diagnosing Alzheimer's disease. The computational methods provides new approaches for appropriately gleaning latent information from mass spectra data...
May 17, 2018: High-throughput
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