Utilization of bis-MPA Dendrimers for the Calibration of Ion Mobility Collision Cross Section Calculations.

Ion mobility-mass spectrometry (IM-MS) has become increasingly popular with the rapid expansion of available techniques and instrumentation. To enable accuracy, standardization, and repeatability of IM-MS measurements, the community requires reliable and well-defined reference materials for calibration and tuning of the equipment. To address this need, synthetic dendrimers of high chemical and structural purity were tested on three ion mobility platforms as potential calibrants.

Simulation of Energy-Resolved Mass Spectrometry Distributions from Surface-Induced Dissociation.

Understanding the relationship between protein structure and experimental data is crucial for utilizing experiments to solve biochemical problems and optimizing the use of sparse experimental data for structural interpretation. Tandem mass spectrometry (MS/MS) can be used with a variety of methods to collect structural data for proteins. One example is surface-induced dissociation (SID), which is used to break apart protein complexes (via a surface collision) into intact subcomplexes and can be performed at multiple laboratory frame SID collision energies.

Destruction and reconstruction of UO using gas-phase reactions.

While the strong axial U[double bond, length as m-dash]O bonds confer high stability and inertness to UO22+, it has been shown that the axial oxo ligands can be eliminated or replaced in the gas-phase using collision-induced dissociation (CID) reactions. We report here tandem mass spectrometry experiments initiated with a gas-phase complex that includes UO22+ coordinated by a 2,6-difluorobenzoate ligand. After decarboxylation to form a difluorophenide coordinated uranyl ion, [UO2(C6F2H3)]+, CID causes elimination of CO, and then CO and C2H2 in sequential dissociation steps, to leave a reactive uranium fluoride ion, [UF2(C2H)]+.

Tandem surface-induced dissociation of protein complexes on an ultrahigh resolution platform.

We describe instrumentation for conducting tandem surface-induced dissociation (tSID) of native protein complexes on an ultrahigh resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. The two stages of SID are accomplished with split lenses replacing the entrance lenses of the quadrupole mass filter (stage 1, referred to herein as SID-Q) and the collision cell (stage 2, Q-SID). After SID-Q, the scattered projectile ions and subcomplexes formed in transit traverse the 20 mm pre-filter prior to the mass-selecting quadrupole, providing preliminary insights into the SID fragmentation kinetics of noncovalent protein complexes.

Surface-Induced Dissociation of Protein Complexes Selected by Trapped Ion Mobility Spectrometry.

Native mass spectrometry (nMS), particularly in conjunction with gas-phase ion mobility spectrometry measurements, has proven useful as a structural biology tool for evaluating the stoichiometry, conformation, and topology of protein complexes. Here, we demonstrate the combination of trapped ion mobility spectrometry (TIMS) and surface-induced dissociation (SID) on a Bruker SolariX XR 15 T FT-ICR mass spectrometer for the structural analysis of protein complexes. We successfully performed SID on mobility-selected protein complexes, including the streptavidin tetramer and cholera toxin B with bound ligands.

Proanthocyanidin Structural Details Revealed by Ultrahigh Resolution FT-ICR MALDI-Mass Spectrometry, H-C HSQC NMR, and Thiolysis-HPLC-DAD.

Proanthocyanidins (condensed tannins) are important in food chemistry, agriculture, and health, driving demand for improvements in structure determination. We used ultrahigh resolution Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) methods to determine the exact composition of individual species in heterogeneous mixtures of proanthocyanidin polymers from grain and leaves. Fragmentation patterns obtained with FT-ICR ESI MS-MS (electrospray ionization) confirmed structural details from thiolysis-high-performance liquid chromatography (HPLC)-diode array detection (DAD) and H-C heteronuclear single quantum coherence (HSQC) NMR.

Obesogenic Memory Maintains Adipose Tissue Inflammation and Insulin Resistance.

Background: Obesity is characterized by visceral adipose tissue (AT) inflammation. Immunosuppressive regulatory T cells (Tregs), phagocytic M2-like macrophages, and innate lymphoid cells type 2 (ILC2) control lean AT inflammation to maintain systemic insulin sensitivity, while the loss of these cells in obesity leads to AT inflammation and insulin resistance (IR).

Objective: The objective of this study was to determine if weight loss following obesity would correct AT inflammation and systemic metabolism.

Simple and Minimally Invasive SID Devices for Native Mass Spectrometry.

We describe a set of simple devices for surface-induced dissociation of proteins and protein complexes on three instrument platforms. All of the devices use a novel yet simple split lens geometry that is minimally invasive (requiring a few millimeters along the ion path axis) and is easier to operate than prior generations of devices. The split lens is designed to be small enough to replace the entrance lens of a Bruker FT-ICR collision cell, the dynamic range enhancement (DRE) lens of a Waters Q-IM-TOF, or the exit lens of a transfer multipole of a Thermo Scientific Extended Mass Range (EMR) Orbitrap.

Stimulation of retrotrapezoid nucleus Phox2b-expressing neurons rescues breathing dysfunction in an experimental Parkinson's disease rat model.

Emerging evidence from multiple studies indicates that Parkinson's disease (PD) patients suffer from a spectrum of autonomic and respiratory motor deficiencies in addition to the classical motor symptoms attributed to substantia nigra degeneration of dopaminergic neurons. Animal models of PD show a decrease in the resting respiratory rate as well as a decrease in the number of Phox2b-expressing retrotrapezoid nucleus (RTN) neurons. The aim of this study was to determine the extent to which substantia nigra pars compact (SNc) degeneration induced RTN biomolecular changes and to identify the extent to which RTN pharmacological or optogenetic stimulations rescue respiratory function following PD-induction.

Chemical Alterations of Dissolved Organic Matter by Permanganate Oxidation.

Dissolved organic matter (DOM) is ubiquitous in raw drinking water and can efficiently scavenge oxidants, such as permanganate. Here, changes to DOM induced by permanganate oxidation under typical drinking water treatment conditions (6 μM, 1 h) to bulk DOM properties, DOM functional groups, and DOM chemical formulae were examined for two DOM isolate types (terrestrial and microbial). Permanganate oxidation did not mineralize DOM, rather changes were compositional in nature.

Application of UAV in Topographic Modelling and Structural Geological Mapping of Quarries and Their Surroundings-Delineation of Fault-Bordered Raw Material Reserves.

A 3D surface model of an active limestone quarry and a vegetation-covered plateau was created using unmanned aerial vehicle (UAV) technique in combination with terrestrial laser scanning (TLS). The aim of the research was to identify major fault zones that dissect the inaccessible quarry faces and to prepare a model that shows the location of these fault zones at the entire study area. An additional purpose was to calculate reserves of the four identified lithological units.

Trimethylamine N-oxide and incident atherosclerotic events in high-risk individuals with diabetes: an ACCORD trial post hoc analysis.

Introduction: Type 2 diabetes mellitus (T2D) confers high atherosclerotic cardiovascular disease (ASCVD) risk. The metabolite trimethylamine N-oxide (TMAO) derived via gut flora has been linked to excess ASCVD.

Research Design And Methods: We analyzed data, biospecimens, and major adverse cardiovascular events (MACEs) from the prospective multicenter randomized Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial to assess its value in 330 high-risk individuals with T2D without evident atherosclerotic disease at enrollment.

Accurate and Efficient Determination of Unknown Metabolites in Metabolomics by NMR-Based Molecular Motif Identification.

Knowledge of the chemical identity of metabolite molecules is critical for the understanding of the complex biological systems to which they belong. Since metabolite identities and their concentrations are often directly linked to the phenotype, such information can be used to map biochemical pathways and understand their role in health and disease. A very large number of metabolites however are still unknown; i.

Design and Performance of a Second-Generation Surface-Induced Dissociation Cell for Fourier Transform Ion Cyclotron Resonance Mass Spectrometry of Native Protein Complexes.

A second-generation ("Gen 2") device capable of surface-induced dissociation (SID) and collision-induced dissociation (CID) for Fourier transform ion cyclotron resonance mass spectrometry of protein complexes has been designed, simulated, fabricated, and experimentally compared to a first-generation device ("Gen 1"). The primary goals of the redesign were to (1) simplify SID by reducing the number of electrodes, (2) increase CID and SID sensitivity by lengthening the collision cell, and (3) increase the mass range of the device for analysis of larger multimeric proteins, all while maintaining the normal instrument configuration and operation. Compared to Gen 1, Gen 2 exhibits an approximately 10× increase in sensitivity in flythrough mode, 7× increase in CID sensitivity for protonated leucine enkephalin (/ 556), and 14× increase of CID sensitivity of 53 kDa streptavidin tetramer.

Metabolic Regulation of Glycolysis and AMP Activated Protein Kinase Pathways during Black Raspberry-Mediated Oral Cancer Chemoprevention.

Oral cancer is a public health problem with an incidence of almost 50,000 and a mortality of 10,000 each year in the USA alone. Black raspberries (BRBs) have been shown to inhibit oral carcinogenesis in several preclinical models, but our understanding of how BRB phytochemicals affect the metabolic pathways during oral carcinogenesis remains incomplete. We used a well-established rat oral cancer model to determine potential metabolic pathways impacted by BRBs during oral carcinogenesis.

Spectroscopic Evidence for Lactam Formation in Terminal Ornithine b and b Fragment Ions.

Infrared multiple photon dissociation action spectroscopy was performed on the AlaOrn b and AlaAlaOrn b fragment ions from ornithine-containing tetrapeptides. Infrared spectra were obtained in the fingerprint region (1000-2000 cm) using the infrared free electron lasers at the Centre Laser Infrarouge d'Orsay (CLIO) facility in Orsay, France, and the free electron lasers for infrared experiments (FELIX) facility in Nijmegen, the Netherlands. A novel terminal ornithine lactam AO b structure was synthesized for experimental comparison and spectroscopy confirms that the b fragment ion from AOAA forms a lactam structure.

Gas-Phase Deconstruction of UO: Mass Spectrometry Evidence for Generation of [OUCH] by Collision-Induced Dissociation of [UO(C≡CH)].

Because of the high stability and inertness of the U=O bonds, activation and/or functionalization of UO and UO remain challenging tasks. We show here that collision-induced dissociation (CID) of the uranyl-propiolate cation, [UO(OC-C≡CH)], can be used to prepare [UO(C≡CH)] in the gas phase by decarboxylation. Remarkably, CID of [UO(C≡CH)] caused elimination of CO to create [OUCH], thus providing a new example of a well-defined substitution of an "yl" oxo ligand of UO in a unimolecular reaction.

Identification of Unknown Metabolomics Mixture Compounds by Combining NMR, MS, and Cheminformatics.

Metabolomics aims at the comprehensive identification of metabolites in complex mixtures to characterize the state of a biological system and elucidate their roles in biochemical pathways. For many biological samples, a large number of spectral features observed by NMR spectroscopy and mass spectrometry (MS) belong to unknowns, i.e.

Social Stress Affects Colonic Inflammation, the Gut Microbiome, and Short-chain Fatty Acid Levels and Receptors.

Objectives: Gastrointestinal disorders, such as inflammatory bowel diseases (IBDs) and functional gastrointestinal disorders (FGIDs), involve disrupted homeostatic interactions between the microbiota and the host. Both disorders are worsened during stress, and in laboratory mice, stress exposure has been shown to change the composition of the gut microbiome. Stress-induced changes to the microbiome exacerbate intestinal inflammation and alter intestinal motility in mice.

Enkephalin degradation in serum of patients with inflammatory bowel diseases.

Background: Inflammatory bowel diseases (IBD) are a group of chronic and recurrent gastrointestinal disorders that are difficult to control. Recently, a new IBD therapy based on the targeting of the endogenous opioid system has been proposed. Consequently, due to the fact that endogenous enkephalins have an anti-inflammatory effect, we aimed at investigating the degradation of serum enkephalin (Met- and Leu-enkephalin) in patients with IBD.

Prolonged restraint stressor exposure in outbred CD-1 mice impacts microbiota, colonic inflammation, and short chain fatty acids.

Stressor-exposure has been shown to exacerbate inflammation and change the composition of the gastrointestinal microbiota; however stressor-induced effects on microbiota-derived metabolites and their receptors are unknown. Thus, bacterial-produced short chain fatty acids (SCFAs), as well as microbial community composition, were assessed in the colons of mice exposed to stress during infection with Citrobacter rodentium. Mice were exposed to overnight restraint on 7 consecutive nights, or left undisturbed as a control.