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https://www.readbyqxmd.com/read/28333435/laser-desorption-ionization-coupled-to-ft-icr-mass-spectrometry-for-studies-of-natural-organic-matter
#1
John W T Blackburn, Will Kew, Margaret C Graham, Dusan Uhrin
Laser desorption/ionization (LDI) was investigated as an ionization method for Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) studies of natural organic matter (NOM). Using International Humic Substances Society standards, Suwannee River fulvic acid (SRFA) and Suwannee River natural organic matter (SRNOM), LDI was found to ionize very similar set of compounds (> 90 % of molecular formulae identity) to the matrix assisted laser desorption/ionization (MALDI), while producing higher quality spectra...
March 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28329870/application-of-imaging-techniques-to-cases-of-drug-induced-crystal-nephropathy-in-preclinical-studies
#2
B Lenz, A Brink, M Siam, A De Paepe, S Bassett, A Eichinger-Chapelon, P Maliver, R Neff, U Niederhauser, B Steinhuber, R Zurbach, T Singer, C Funk, F Schuler, M Albassam, S Schadt
A number of drugs can cause precipitates within renal tubules leading to crystal nephropathy. Crystal nephropathy is usually an exposure-related finding and is not uncommon in preclinical studies, where high doses are tested. An understanding of the nature of precipitates is important for human risk assessment and further development. Our aim was to investigate the ability of various imaging techniques to detect the presence of drugs or metabolites in renal crystals. We applied matrix-assisted laser desorption/ionization - Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS) imaging, Raman and infrared microspectroscopy, scanning electron microscopy coupled with energy dispersive X-ray (SEM/EDX) spectroscopy and standard histopathology to cases of drug-induced crystal nephropathy, induced in rodents and primates by four compounds...
February 27, 2017: Toxicological Sciences: An Official Journal of the Society of Toxicology
https://www.readbyqxmd.com/read/28328038/superbasic-alkyl-substituted-bisphosphazene-proton-sponges-a-new-class-of-deprotonating-matrices-for-negative-ion-matrix-assisted-ionization-laser-desorption-mass-spectrometry-of-low-molecular-weight-hardly-ionizable-analytes
#3
C D Calvano, T R I Cataldi, J F Kögel, A Monopoli, F Palmisano, J Sundermeyer
RATIONALE: Here hardly ionizable and low molecular weight compounds are detected in negative ion mode by using novel superbasic proton sponges based on 1,8-bisphosphazenylnaphthalene (PN) as MALDI matrices. Among the selected proton sponges, 1,8-bis(trispyrrolidinophosphazenyl)naphthalene (TPPN) has shown the best behaviour as matrix since it allows the direct detection of intact cholesterol without derivatization also in real challenging samples. METHODS: Very weakly acidic compounds such as sterols, steroids, fatty alcohols and saccharides were detected in reflectron negative ion mode by a MALDI TOF/TOF system equipped with a neodymium-doped yttrium lithium fluoride (Nd:YLF) laser (345 nm) with typical mass accuracy of 10 ppm...
July 30, 2016: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28328033/effects-of-molecular-weight-and-cationization-agent-on-the-sensitivity-of-bi-cluster-secondary-ion-mass-spectrometry
#4
Makiko Fujii, Rie Shishido, Takaya Satoh, Shigeru Suzuki, Jiro Matsuo
RATIONALE: Bi cluster secondary ion mass spectrometry (SIMS) is one of the most promising tools for precise analysis of synthetic polymers. However, the sensitivity in the high-mass region is still insufficient compared with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). Accordingly, the effects of metal assistance (cationization agents) were investigated in this study. METHODS: To investigate the effects caused by varying the ionization agent, three different polyethylene glycol (PEG) samples were prepared, one with an Ag-deposited film, and two others mixed with Ag and Na, respectively...
July 30, 2016: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28328023/identification-of-microorganisms-in-biofluids-of-individuals-with-periodontitis-and-chronic-kidney-disease-using-matrix-assisted-laser-desorption-ionization-time-of-flight-mass-spectrometry
#5
Levy Anderson César Alves, Rafael Celestino Souza, Taciana Mara Couto da Silva, Andreia Watanabe, Meriellen Dias, Maria Anita Mendes, Ana Lídia Ciamponi
RATIONALE: Chronic kidney disease (CKD) and periodontitis (PD) are important health issues. There is a large variety of microorganisms related to the pathogenesis of periodontitis, and optimising the time and the cost of laboratory assays to detect these organisms is highly valuable in the medical field. METHODS: Bacteria were isolated from saliva and oral biofilm of 30 adolescents and young adults with definite medical and dental diagnosis of CKD and PD, respectively, and proteins were extracted for microorganism identification by means of the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) technique...
May 30, 2016: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28328018/abundance-correction-for-mass-discrimination-effects-in-polymer-mass-spectra
#6
Martin S Engler, Sarah Crotty, Markus J Barthel, Christian Pietsch, Ulrich S Schubert, Sebastian Böcker
RATIONALE: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) is frequently used to analyze homo- and copolymers, i.e. for computing copolymer fingerprints. However, the oligomer abundances are influenced by mass discrimination, i.e. mass- and composition-dependent ionization. We have developed a computational method to correct the abundance bias caused by the mass discrimination. METHODS: MALDI-TOFMS in combination with computational methods was used to investigate three random copolymers with different ratios of styrene and isoprene...
May 30, 2016: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28323431/au38-sph-24-au38-protected-with-aromatic-thiolate-ligands
#7
Milan Rambukwella, Shayna Burrage, Marie Neubrander, Oscar Baseggio, Edoardo Aprà, Mauro Stener, Alessandro Fortunelli, Amala Dass
Au38(SR)24 is one of the most extensively investigated gold nanomolecules along with Au25(SR)18 and Au144(SR)60. However, so far it has only been prepared using aliphatic-like ligands, where R = -SC6H13, -SC12H25 and -SCH2CH2Ph. Au38(SCH2CH2Ph)24 when reacted with HSPh undergoes core-size conversion to Au36(SPh)24, and existing literature suggests that Au38(SPh)24 cannot be synthesized. Here, contrary to prevailing knowledge, we demonstrate that Au38(SPh)24 can be prepared if the ligand exchanged conditions are optimized, under delicate conditions, without any formation of Au36(SPh)24...
March 21, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28320881/lpto-pg0027-is-required-for-lipid-a-1-phosphatase-activity-in-porphyromonas-gingivalis-w50
#8
Minnie Rangarajan, Joseph Aduse-Opoku, Ahmed Hashim, Graham McPhail, Zofia Luklinska, M Florencia Haurat, Mario F Feldman, Michael A Curtis
Porphyromonas gingivalis produces outer-membrane vesicles (OMVs) rich in virulence factors including cysteine-proteases and A-LPS, one of the two lipopolysaccharides (LPS) produced by this organism. Previous studies had suggested that A-LPS together with PG0027, an outer-membrane (OM) protein, may be involved in OMV-formation. Their roles in this process were examined using parent W50 and mutant ΔPG0027 strains. Inactivation of PG0027 caused a reduction in yield of OMVs. Lipid A from cells and OMVs of P. gingivalis W50 and ΔPG0027 strains were analysed by matrix-assisted laser-desorption-ionisation-time of flight mass spectrometry (MALDI-TOF- MS)...
March 20, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28318232/histology-compatible-maldi-mass-spectrometry-based-imaging-of-neuronal-lipids-for-subsequent-immunofluorescent-staining
#9
Ibrahim Kaya, Wojciech Michno, Dimitri Brinet, Yasmine Iacone, Giulia Zanni, Kaj Blennow, Henrik Zetterberg, Jörg Hanrieder
Matrix assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) enables acquisition of spatial distribution maps for molecular species in situ. This can provide comprehensive insights on the pathophysiology of different diseases. However, current sample preparation and MALDI-IMS acquisition methods have limitations in preserving molecular and histological tissue morphology, resulting in interfered correspondence of MALDI-IMS data with subsequently acquired immunofluorescent staining results...
March 20, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28317378/scrambled-internal-standard-sis-method-for-high-throughput-protein-quantification-by-maldi-ms-ms
#10
Toshihiro Yoneyama, Sumio Ohtsuki, Masanori Tachikawa, Yasuo Uchida, Tetsuya Terasaki
Matrix-assisted laser desorption ionization (MALDI) would be advantageous for high-throughput MS acquisition, but suffers from low signal reproducibility. The purpose of this study was to establish a reliable MALDI-tandem mass spectrometry (MS/MS)-based high-throughput quantification of tryptic peptides using our newly developed scrambled internal standard (sIS) method. The standard curves obtained with sIS peptides showed good linearity over a wide concentration range (5-1000 fmol/μL) compared to the IS-free method, and the coefficient of variation (CV) of data points at each concentration (5-1000 fmol/μL) was significantly reduced...
March 20, 2017: Journal of Proteome Research
https://www.readbyqxmd.com/read/28315638/determination-of-triazines-and-triazoles-in-grapes-using-atmospheric-pressure-matrix-assisted-laser-desorption-ionization-high-resolution-mass-spectrometry
#11
Vishal Mahale, Ajeet Singh, Gayatri S Phadke, Avinash D Ghanate, Dasharath P Oulkar, Kaushik Banerjee, Venkateswarlu Panchagnula
A chromatography-free atmospheric pressure matrix-assisted laser desorption/ionization high-resolution mass spectrometry (AP-MALDI HRMS) method is described for the simultaneous and quantitative detection of triazines and triazoles in grapes. The analytes were detected reproducibly with high mass accuracy (mass error within 5 ppm) and further confirmed by collision-induced dissociation fragmentation in tandem MS. The LODs and LOQs for all the analytes were found to be in the nanogram per gram level (15-20 ng/g LOQ)...
March 18, 2017: Journal of AOAC International
https://www.readbyqxmd.com/read/28303824/matrix-assisted-laser-desorption-ionisation-time-of-flight-mass-spectrometry-rapid-detection-of-carbapenamase-activity-in-acinetobacter-baumannii-isolates
#12
Noha Abouseada, May Raouf, Eman El-Attar, Pacinte Moez
INTRODUCTION: Carbapenamase-producing Acinetobacter baumannii are an increasing threat in hospitals and Intensive Care Units. Accurate and rapid detection of carbapenamase producers has a great impact on patient improvement and aids in implementation of infection control measures. AIM: In this study, we describe the use of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI TOF MS) to identify carbapenamase-producing A. baumannii isolates in up to 3 h...
January 2017: Indian Journal of Medical Microbiology
https://www.readbyqxmd.com/read/28301258/maldi-mass-spectrometry-reveals-that-cumulus-cells-modulate-the-lipid-profile-of-in-vitro-matured-bovine-oocytes
#13
Alessandra A Vireque, Alessandra Tata, Katia Roberta A Belaz, João Gabriel V Grázia, Fábio N Santos, Daniel R Arnold, Andrea C Basso, Marcos N Eberlin, Marcos Felipe Silva-de-Sá, Rui A Ferriani, Ana Carolina J Sá Rosa-E-Silva
The influence of cumulus cells (CC) on the lipid profile of bovine oocytes matured in two different lipid sources was investigated. Cumulus-oocyte complexes (COC) or denuded oocytes (DO) were matured in tissue culture medium (TCM) supplemented with fetal bovine serum (FBS) or serum substitute supplement (SSS). Lipid profiles of TCM, serum supplements, immature CC and oocyte (IO), and in vitro-matured oocytes from COC and DO were then analyzed by matrix assisted laser desorption ionization mass spectrometry (MALDI-MS) and submitted to partial least squares-discriminant analysis (PLS-DA)...
April 2017: Systems Biology in Reproductive Medicine
https://www.readbyqxmd.com/read/28300831/immunoproteomic-identification-and-characterization-of-ni-2-regulated-proteins-implicates-ni-2-in-the-induction-of-monocyte-cell-death
#14
Annika Jakob, Franz Mussotter, Stefanie Ohnesorge, Lisa Dietz, Julian Pardo, Ian D Haidl, Hermann-Josef Thierse
Nickel allergy is the most common cause of allergic reactions worldwide, with cutaneous and systemic effects potentially affecting multiple organs. Monocytes are precursors of not only macrophages but also dendritic cells, the most potent activators of nickel hypersensitivity. Monocytes are themselves important antigen-presenting cells, capable of nickel-specific T-cell activation in vivo and in vitro, in addition to being important for immediate innate immune inflammation. To elucidate early Ni(2+)-dependent inflammatory molecular mechanisms in human monocytes, a Ni(2+)-specific proteomic approach was applied...
March 16, 2017: Cell Death & Disease
https://www.readbyqxmd.com/read/28300263/size-specific-emission-in-peptide-capped-gold-quantum-clusters-with-tunable-photoswitching-behavior
#15
Abhishek Baral, Kingshuk Basu, Sirshendu Ghosh, Kalishankar Bhattacharyya, Subhasish Roy, Ayan Datta, Arindam Banerjee
Three different types of fluorescent gold clusters (namely blue, green and red emitting) have been prepared from a gold precursor (chloroauric acid) under moderate conditions in aqueous medium. A cysteine containing dipeptide has been used for the formation of these quantum clusters as this peptide molecule contains a thiol group in the side chain to cap these nascently formed clusters and the free amino and carboxylic moieties assist in water solubility. Thus, the clusters are also environmentally friendly as the capped peptide is made up of only naturally occurring protein amino acids...
March 16, 2017: Nanoscale
https://www.readbyqxmd.com/read/28299594/dissecting-pistil-responses-to-incompatible-and-compatible-pollen-in-self-incompatibility-brassica-oleracea-using-comparative-proteomics
#16
Jing Zeng, Qiguo Gao, Songmei Shi, Xiaoping Lian, Richard Converse, Hecui Zhang, Xiaohong Yang, Xuesong Ren, Song Chen, Liquan Zhu
Angiosperms have developed self-incompatibility (SI) systems to reject self-pollen, thereby promoting outcrossing. The Brassicaceae belongs to typical sporophytic system, having a single S-locus controlled SI response, and was chosen as a model system to study SI-related intercellular signal transduction. In this regard, the downstream factor of EXO70A1 was unknown. Here, protein two-dimensional electrophoresis (2-DE) method and coupled with matrix-assisted laser desorption ionization/time of flight of flight mass spectrometry (MALDI-TOF -MS) and peptide mass fingerprinting (PMF) was used to further explore the mechanism of SI responses in Brassica oleracea L...
March 16, 2017: Protein Journal
https://www.readbyqxmd.com/read/28295836/profiling-n-glycans-of-the-egg-jelly-coat-of-the-sea-urchin-paracentrotus-lividus-by-maldi-tof-mass-spectrometry-and-capillary-liquid-chromatography-electrospray-ionization-ion-trap-tandem-mass-spectrometry-systems
#17
Umut Şahar, Remziye Deveci
Sea urchin eggs are surrounded by a carbohydrate-rich layer, termed the jelly coat, that consists of polysaccharides and glycoproteins. In the present study, we describe two mass spectrometric strategies to characterize the N-glycosylation of the Paracentrotus lividus egg jelly coat, which has an alecithal-type extracellular matrix like mammalian eggs. Egg jelly was isolated, lyophilized, and dialysed, followed by peptide N-glycosidase F (PNGase-F) treatment to release N-glycans from their protein chain. These N-glycans were then derivatized by permethylation reaction, and analysed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and capillary liquid chromatography electrospray ionization-ion trap tandem mass spectroscopy (CapLC ESI-Ion trap-MS/MS)...
March 10, 2017: Molecular Reproduction and Development
https://www.readbyqxmd.com/read/28294933/differences-in-sheep-and-goats-milk-microbiological-profile-between-conventional-and-organic-farming-systems-in-greece
#18
Eleni Malissiova, Theofilos Papadopoulos, Aikaterini Kyriazi, Maria Mparda, Christina Sakorafa, Antonios Katsioulis, Anna Katsiaflaka, Maria Kyritsi, Antonios Zdragas, Christos Hadjichristodoulou
The aim of this study was to examine differences in the microbiological profile and antimicrobial resistance of bacteria isolated from milk from organic and conventional sheep and goat farms. Twenty-five organic and 25 conventional sheep and goat farms in the region of Thessaly, Greece participated in this study. A standardised detailed questionnaire was used to describe farming practices. A total of 50 samples were collected and analysed for total viable count (TVC), total coliform count (TCC) and somatic cell count (SCC), while Staphylococcus aureus and Escherichia coli were isolated using standard methods...
March 15, 2017: Journal of Dairy Research
https://www.readbyqxmd.com/read/28294237/surface-assisted-laser-desorption-ionization-time-of-flight-mass-spectrometry-of-small-drug-molecules-and-high-molecular-weight-synthetic-biological-polymers-using-electrospun-composite-nanofibers
#19
Juan Bian, Susan V Olesik
Polyacrylonitrile/Nafion®/carbon nanotube (PAN/Nafion®/CNT) composite nanofibers were prepared using electrospinning. These electrospun nanofibers were studied as possible substrates for surface-assisted laser desorption/ionization (SALDI) and matrix-enhanced surface-assisted laser desorption/ionization time-of-flight mass spectrometry (ME-SALDI/TOF-MS) for the first time in this paper. Electrospinning provides this novel substrate with a uniform morphology and a narrow size distribution, where CNTs were evenly and firmly immobilized on polymeric nanofibers...
March 15, 2017: Analyst
https://www.readbyqxmd.com/read/28294158/improved-maldi-imaging-ms-analysis-of-phospholipids-using-graphene-oxide-as-new-matrix
#20
Zhongjie Wang, Yan Cai, Yi Wang, Xinwen Zhou, Ying Zhang, Haojie Lu
Matrix assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) is an increasingly important technique for detection and spatial localization of phospholipids on tissue. Due to the high abundance and being easy-to-ionize of phosphatidylcholine (PC), therefore, selecting matrix to yield signals of other lipids has become the most crucial factor for a successful MALDI-IMS analysis of phospholipids. Herein, graphene oxide (GO) was proposed as a new matrix to selectively enhance the detection of other types of phospholipids that are frequently suppressed by the presence of PC in positive mode...
March 15, 2017: Scientific Reports
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