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MALDI and matrix

Thankan Jayasekharan, Shyam L Gupta, Vikas Dhiman
The intrinsic binding ability of seven natural peptides (oxytocin, arg8 -vasopressin, bradykinin, angiotensin-I, substance-P, somatostatin, and neurotensin) with copper in two different oxidation states (CuI/II ) derived from different Cu+/2+ precursor sources have been investigated for their charge dependent binding characteristics. The peptide-CuI/II complexes, [M - (n-1)H + nCuI ] and [M - (2n-1)H + nCuII ] are prepared/generated by the reaction of peptides with CuI solution/Cu-target and CuSO4 solution, and are analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS)...
January 15, 2018: Journal of Mass Spectrometry: JMS
Lingpeng Zhan, Xiaobo Xie, Yafeng Li, Huihui Liu, Caiqiao Xiong, Zongxiu Nie
Saccharide isomer differentiation has been a challenge in glycomics, as the lack of technology to decipher fully the diverse structures of compositions, linkages and anomeric configurations. Several mass spectrometry-based methods have been applied to the discrimination of disaccharide isomers, but limited quantitative analyses have been reported. In the present study, MALDI-LIFT-TOF/TOF has been investigated to differentiate and relatively quantify underivatized glucose-containing disaccharide isomers that differ in composition, connectivity or configuration...
January 12, 2018: Analytical Chemistry
Ji-Cheng Niu, Ting Zhou, Li-Li Niu, Zhen-Sheng Xie, Fang Fang, Fu-Quan Yang, Zhi-Yong Wu
In this work, fast isoelectric focusing (IEF) was successfully implemented on an open paper fluidic channel for simultaneous concentration and separation of proteins from complex matrix. With this simple device, IEF can be finished in 10 min with a resolution of 0.03 pH units and concentration factor of 10, as estimated by color model proteins by smartphone-based colorimetric detection. Fast detection of albumin from human serum and glycated hemoglobin (HBA1c) from blood cell was demonstrated. In addition, off-line identification of the model proteins from the IEF fractions with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was also shown...
January 11, 2018: Analytical and Bioanalytical Chemistry
Anthony Maus, Rudolph Mignon, Franco Basile
The use of offline liquid chromatography-matrix assisted laser desorption/ionization (LC-MALDI) tandem mass spectrometry (MS/MS) for bottom-up proteomics offers advantages in terms of cost, ease of use, and the time-decoupled nature of the separation step and the mass analysis. A method was developed to improve the capabilities of LC-MALDI-MS/MS in terms of protein identification in a bottom-up proteomic workflow. Enhanced protein identification is achieved by an increase in the MALDI signal intensity of the precursor peptides brought about by coating the MALDI plate with a thin film of graphite powder...
January 8, 2018: Analytical Biochemistry
Jan-Hinrich Rabe, Denis A Sammour, Sandra Schulz, Bogdan Munteanu, Martina Ott, Katharina Ochs, Peter Hohenberger, Alexander Marx, Michael Platten, Christiane A Opitz, Daniel S Ory, Carsten Hopf
Multimodal imaging combines complementary platforms for spatially resolved tissue analysis that are poised for application in life science and personalized medicine. Unlike established clinical in vivo multimodality imaging, automated workflows for in-depth multimodal molecular ex vivo tissue analysis that combine the speed and ease of spectroscopic imaging with molecular details provided by mass spectrometry imaging (MSI) are lagging behind. Here, we present an integrated approach that utilizes non-destructive Fourier transform infrared (FTIR) microscopy and matrix assisted laser desorption/ionization (MALDI) MSI for analysing single-slide tissue specimen...
January 10, 2018: Scientific Reports
Victoire de Lastours, Tiphaine Goulenok, François Guérin, Hervé Jacquier, Cindy Eyma, Françoise Chau, Vincent Cattoir, Bruno Fantin
Epidemiological data suggest that ceftriaxone may promote the emergence of commensal AmpC-overproducing Enterobacteriaceae because of a high biliary excretion. We tested this hypothesis in hospitalized patients either treated by ceftriaxone alone or receiving no antibiotics. Hospitalized patients with no previous antibiotics or hospitalization in the last 3 months, treated only with ceftriaxone, were prospectively included. For each ceftriaxone-treated patient, a control patient receiving no antibiotics was included...
January 10, 2018: European Journal of Clinical Microbiology & Infectious Diseases
Allison Maree Heskes, Tamil C M Sundram, Berin Alain Boughton, Niels Bjerg Jensen, Nikolaj Lervad Hansen, Christoph Crocoll, Federico Cozzi, Simon Rasmussen, Britta Hamberger, Björn Hamberger, Dan Staerk, Birger Lindberg Møller, Irini Pateraki
Vitex agnus-castus L. (Lamiaceae) is a medicinal plant historically used throughout the Mediterranean region to treat menstrual cycle disorders and is still used today as a clinically effective treatment for premenstrual syndrome. The pharmaceutical activity of the plant extract is linked to its ability to lower prolactin levels. This feature has been attributed to the presence of dopaminergic diterpenoids that can bind to dopamine receptors in the pituitary gland. Phytochemical analyses of V. agnus-castus show that it contains an enormous array of structurally related diterpenoids and, as such holds potential as a rich source of new dopaminergic drugs...
January 8, 2018: Plant Journal: for Cell and Molecular Biology
Ramakrishna Itteboina, U Divya Madhuri, Partha Ghosal, Monica Kannan, Tapan Kumar Sau, Tatsuya Tsukuda, Shweta Bhardwaj
Developing efficient ways to control the nanocluster properties and synthesize atomically-precise metal nanoclusters are the foremost goals in the field of metal nanocluster research. In this article, we demonstrate that the direct synthesis of atomically-precise, hydrophilic metal nanoclusters as well as tuning of their properties can be achieved by an appropriate selection of reactants, binding ligand, and their proportions. Thus a facile, single-step method has been developed for the direct synthesis of Au18(SC2H4CO2H)14 nanocluster in an aqueous medium under ambient conditions...
January 9, 2018: Journal of Physical Chemistry. A
Matthew B O'Rourke, Benjamin B A Raymond, Steven P Djordjevic, Matthew P Padula
Tissue imaging using matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a well-established technique that, in recent years, has seen wider adoption and novel application. Applications such imaging mass spectrometry (IMS) and biotyping are beginning to gain greater exposure and use; however, with limitations in optimization methods, producing the best result often relies on the ability to customize the physical characteristics of the instrumentation, a task that is challenging for most mass spectrometry laboratories...
January 8, 2018: Journal of the American Society for Mass Spectrometry
Ming Guan, Zhen Zhang, Shilei Li, Jian'an Liu, Lu Liu, Hui Yang, Yangyang Zhang, Tie Wang, Zhenwen Zhao
Owing to the diversity of lipids, profiling and imaging multiple classes of lipids in one analysis by matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI MSI) is a great challenge. In this work, polyvinylpyrrolidone (PVP) capped silver nanoparticles (AgNPs) was used as the matrix for MALDI MSI for the first time to simultaneously analyze 10 classes of lipids from the brain. This analysis included fatty acids and their derivatives, sterols, CPAs, LPA and PAs, LPE and PEs, LPC and PCs, PS, Cers, SMs, and MAGs and DAGs, and other small metabolites...
March 1, 2018: Talanta
Xiu Huang, Qian Liu, Wei Gao, Yawei Wang, Zhou Nie, Shouzhuo Yao, Guibin Jiang
As an important class of emerging chemical contaminants, short-chain chlorinated paraffins (SCCPs) are considered as one of the most challenging groups of compounds to analyze. In this paper, we report a new method for fast screening of SCCPs based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with graphene as a matrix and 2,5,6,9-tetrachlorodecane as an internal standard. We found that the use of graphene as MALDI matrix generated high peak intensities for SCCPs while producing few background noises...
March 1, 2018: Talanta
Stephan Lefcoski, Kimberly Kew, Shaun Reece, Maria J Torres, Justin Parks, Sky Reece, Lisandra E de Castro Brás, Jitka A I Virag
EphrinA1 is a tyrosine kinase receptor localized in the cellular membrane of healthy cardiomyocytes, the expression of which is lost upon myocardial infarction (MI). Intra-cardiac injection of the recombinant form of ephrinA1 (ephrinA1-Fc) at the time of ligation in mice has shown beneficial effects by reducing infarct size and myocardial necrosis post-MI. To date, immunohistochemistry and Western blotting comprise the only experimental approaches utilized to localize and quantify relative changes of ephrinA1 in sections and homogenates of whole left ventricle, respectively...
January 5, 2018: Journal of the American Society for Mass Spectrometry
De-Xin Dong, Zhi-Gang Ji, Han-Zhong Li, Wei-Gang Yan, Yu-Shi Zhang
Objective To evaluate the application of weak cation exchange (WCX) magnetic bead-based Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) in detecting differentially expressed proteins in the urine of renal clear cell carcinoma (RCCC) and its value in the early diagnosis of RCCC.Methods Eleven newly diagnosed patients (10 males and 1 female, aged 46-78, mean 63 years) of renal clear cell carcinoma by biopsy and 10 healthy volunteers (all males, aged 25-32, mean 29.7 years) were enrolled in this study...
December 30, 2017: Chinese Medical Sciences Journal, Chung-kuo i Hsüeh K'o Hsüeh Tsa Chih
Andrea Renee Kelley, George Perry, Stephan B H Bach
The increase of insoluble senile plaques in the brain is a primary hallmark of Alzheimer's disease. The usefulness of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with tandem MS for the characterization of senile plaques from AD brains and the relevance of the components identified to furthering AD research using MS is discussed. 33 components were reproducibly observed within tryptic aliquots of senile plaques from two different AD brains after sample preparation optimization...
January 4, 2018: ACS Chemical Neuroscience
Shuhei Yamada, Nobuhiro Zaima, Yukihiro Yoshimura, Shiori Inaba, Takamichi Fujimori, Tetsuya Sogon, Tatsuya Moriyama
RATIONALE: Anthocyanins, which belong to a class of molecules called flavonoids, are known to have beneficial effects for both humans and animals. Many physiological functions have been attributed to anthocyanins since ancient times. The most important function is the relief of eyestrain, but the biodistribution of anthocyanins remains unknown. In this study, we analyzed the kinetics of anthocyanin species in mice eyeballs and surrounding tissues. METHODS: We used mice that were administered bilberry extract solution intraperitoneally...
January 3, 2018: Rapid Communications in Mass Spectrometry: RCM
Sebastiaan Van Nuffel, Nicolas Elie, Ethan Yang, Julius Nouet, David Touboul, Pierre Chaurand, Alain Brunelle
Imaging mass spectrometry (IMS) has become a powerful tool to characterise the spatial distribution of biomolecules in thin tissue sections. In the case of matrix-assisted laser desorption ionisation (MALDI) IMS, homogeneous matrix deposition is critical to produce high quality ion images and sublimation in particular has shown to be an excellent matrix deposition method for the imaging of lipids. Matrix deposition by sublimation is, however, a completely solvent-free system, which ought to prevent the mixing of matrix and analytes thought to be necessary for successful MALDI...
January 3, 2018: Analytical Chemistry
Jianing Wang, Chunyan Wang, Xianlin Han
In matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) analysis and imaging of lipids, comprehensive ionization of lipids simultaneously by a universal matrix is a very challenging problem. Ion suppression of readily ionizable lipids to others is common. To overcome this obstacle and enhance the coverage of MALDI MS analysis and imaging of lipids, we developed a novel strategy employing a mixture of matrices, each of which is capable of selective ionization of different lipid classes. Given that MALDI MS with either 9-aminoacridine (9-AA) or N-(1-naphthyl) ethylenediamine dihydrochloride (NEDC) yields weak in-source decay which is critical for analysis of complex biological samples and possesses orthogonal selectivity for ionization of lipid classes, we tested the mixtures of NEDC and 9-AA with different ratios for analysis of standard lipids and mouse brain lipid extracts...
February 13, 2018: Analytica Chimica Acta
Dalia H Abdelkader, Mohamed A Osman, Sanaa A El-Gizawy, Suzan J Hawthorne, Ahmed M Faheem, Paul A McCarron
We describe the development of a nanoparticulate system, with variation of poly(ethylene glycol) (PEG) content, capable of releasing therapeutic levels of bioactive insulin for extended periods of time. Recombinant human insulin was encapsulated in poly(d,l-lactide-co-glycolide) nanoparticles, manufactured with variation in poly(ethylene glycol) content, and shown to be stable for 6days using SDS-PAGE, western blot and MALDI MS. To determine if insulin released from this sustained release matrix could stimulate migration of cell types normally active in dermal repair, a model wound was simulated by scratching confluent cultures of human keratinocytes (HaCaT) and fibroblasts (Hs27)...
December 26, 2017: European Journal of Pharmaceutical Sciences
Haining Guan, Xiaoqin Diao, Fan Jiang, Jianchun Han, Baohua Kong
Enzymatic hydrolysis of soy protein isolate by Corolase PP under high hydrostatic pressure conditions was studied and the effects of hydrolysis on antioxidant and antihypertensive activities were investigated. As observed, high hydrostatic pressure (80-300MPa) enhanced the hydrolytic efficiency of Corolase PP and decreased the surface hydrophobicity of the hydrolysates. Hydrolysates obtained at 200MPa for 4h had higher bioactivities (reducing power, ABTS radical-scavenging and ACE inhibitory activities). The molecular weight (MW) determination indicated that hydrolysis at high hydrostatic pressure could increase the production of small peptides (<3kDa) and the amino acid sequences of these peptides with different inhibitory abilities, less than 3kDa, in hydrolysates were identified using matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI TOF MS)...
April 15, 2018: Food Chemistry
Katerina Chudejova, Michal Bohac, Anna Skalova, Veronika Rotova, Costas C Papagiannitsis, Jana Hanzlickova, Tamara Bergerova, Jaroslav Hrabák
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) -based identification of bacteria and fungi significantly changed the diagnostic process in clinical microbiology. We describe here a novel technique for bacterial and yeast deposition on MALDI target using an automated workflow resulting in an increase of the microbes' score of MALDI identification. We also provide a comparison of four different sample preparation methods. In the first step of the study, 100 Gram-negative bacteria, 100 Gram-positive bacteria, 20 anaerobic bacteria and 20 yeasts were spotted on the MALDI target using manual deposition, semi-extraction, wet deposition onto 70% formic acid and by automatic deposition using MALDI Colonyst...
2017: PloS One
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