Electrospray Ionization Tandem Mass Spectrometry Research Articles

Electrospray ionization tandem mass spectrometry with collision induced dissociation of uranyl peroxide nanoclusters containing various uranyl bridging ligands.

We utilized electrospray ionization tandem mass spectrometry with collision-induced dissociation (ESI-MS/MS) to study the gas phase fragmentation of uranyl peroxide nanoclusters with hydroxo, peroxo, oxalate, and pyrophosphate bridging ligands. These nanoclusters fragment into uranium monomers and dimers with mass-to-charge (m/z) ratios in the 280-380 region. The gas phase fragmentation of each cluster studied yields a distinct UO6- anion attributed to the cleavage of a uranyl ion bound to 2 peroxide groups, along with other anions that can be attributed to the initial composition of the nanoclusters.

Catalytic behavior of nitrous acid for acetaminophen transformation during the freezing process

This study demonstrates the transformation of acetaminophen by reactive nitrous acid in a frozen solution and its abnormal stoichiometry. The chemical reaction between acetaminophen and nitrous acid (AAP/NO2− system) was negligible in the aqueous solution; however, the reaction rapidly progressed if the solution started to freeze. The ultrahigh performance liquid chromatography–electrospray ionization tandem mass spectrometry measurements showed that polymerized acetaminophen and nitrated acetaminophen were formed in the proceeding reaction. Electron paramagnetic resonance spectroscopy measurements showed that nitrous acid oxidized acetaminophen via a one-electron transfer reaction producing acetaminophen-derived radical species, which is the cause of acetaminophen polymerization. We demonstrated that a relatively smaller dose of nitrite than acetaminophen caused significant acetaminophen degradation in the frozen AAP/NO2− system and revealed that the dissolved oxygen content notably affected acetaminophen degradation. We showed that the reaction occurs in a natural Arctic lake matrix (nitrite and acetaminophen spiked). Considering that the freezing phenomenon is common in the natural environment, our research provides a possible scenario for the freezing chemistry of nitrite and pharmaceuticals in environmental chemistry.

Tyrosinase inhibitory activity of Sargassum fusiforme and characterisation of bioactive compounds.

Sargassum fusiforme (Harvey) Setchell, also known as Tot (in Korean) and Hijiki (in Japanese), is widely consumed in Korea, Japan, and China due to its health promoting properties. However, the bioactive component behind the biological activity is still unknown. We aimed to optimise the extraction conditions for achieving maximum tyrosinase inhibition activity by using two sophisticated statistical tools, that is, response surface methodology (RSM) and artificial neural network (ANN). Moreover, high-resolution mass spectrometry (HRMS) was used to tentatively identify the components, which are then further studied for molecular docking study using 2Y9X protein. RSM central composite design was used to conduct extraction using microwave equipment, which was then compared to ANN. Electrospray ionisation tandem mass spectrometry (ESI-MS/MS) was used to tentatively identify bioactive components, which were then docked to the 2Y9X protein using AutoDock Vina and MolDock software. Maximum tyrosinase inhibition activity of 79.530% was achieved under optimised conditions of time: 3.27 min, temperature: 128.885°C, ethanol concentration: 42.13%, and microwave intensity: 577.84 W. Furthermore, 48 bioactive compounds were tentatively identified in optimised Sargassumfusiforme (OSF) extract, and among them, seven phenolics, five flavonoids, five lignans, six terpenes, and five sulfolipids and phospholipids were putatively reported for the first time in Sargassum fusiforme. Among 48 bioactive components, trifuhalol-A, diphlorethohydroxycarmalol, glycyrrhizin, and arctigenin exhibited higher binding energies for 2Y9X. Taken together, these findings suggest that OSF extract can be used as an effective skin-whitening source on a commercial level and could be used in topical formulations by replacing conventional drugs.

The Assessment of the Skin-Whitening and Anti-Wrinkling Effects of Anemarrhena asphodeloides Bunge Root Extracts and the Identification of Nyasol in a Developed Cream Product

Anemarrhena asphodeloides Bunge (A. asphodeloides Bunge) root extract contains nyasol as its main ingredient. Nyasol was extracted and prepared as a cosmetic raw material in 95% ethanol. To identify nyasol as a marker compound qualitative analysis was performed using ultra-performance liquid chromatographyi coupled with electrospray ionization–tandem mass spectrometry. Below a nyasol content of 12 μg/mL, the root extract exhibited negligible cytotoxicity. In this concentration range, melanin production in B16F10 mouse melanoma cells decreased as the concentration of nyasol increased, indicating a skin-whitening effect. In addition, an antiwrinkling effect was confirmed by evaluating the inhibition of MMP-1 protein expression in TNF-α-treated HaCaT cells by either A. asphodeloides Bunge root extract (>0.31 μg/mL) or nyasol (>0.25 μg/mL). High-performance liquid chromatography-coupled with a photodiode detector array was used to show that our extract contained 5.06 ± 0.01% nyasol. Furthermore, when this analysis method was applied for the quality control of a cream product containing 2 wt.% of A. asphodeloides Bunge root extract, the measured content of nyasol (0.1%) was over 90% of the nominal quantity. Therefore, the product was deemed to be within the required quality standards.

Natural Occurrence of Alternaria Toxins in Citrus-Based Products Collected from China in 2021.

A total of 181 citrus-based products, including dried fruits, canned fruits, and fruit juices, collected from China and from abroad in 2021 were analyzed for the four Alternaria toxins (ALTs): alternariol (AOH), alternariol monomethyl ether (AME), tentoxin (TEN), and tenuazonic acid (TeA) via ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS). Although the concentrations of the four ALTs varied by product and geographically, TeA was the predominant toxin followed by AOH, AME, and TEN. Products made in China showed higher levels of ALTs than those made abroad. Maximum levels of TeA, AOH, and AME in analyzed domestic samples were 4.9-fold, 1.3-fold, and 1.2-fold, respectively, higher than those in imported products. Furthermore, 83.4% (151/181) of the analyzed citrus-based products were contaminated with at least two or more ALTs. There were significant positive correlations between AOH and AME, AME and TeA, and TeA and TEN in all analyzed samples. More importantly, the solid and the condensed liquid products had higher concentrations of ALTs than the semi-solid product samples, as well as tangerines, pummelos, and grapefruits compared to the other kinds of citrus-based products. In conclusion, co-contamination with ALTs in commercially available Chinese citrus-based products was universal. Extensive and systematic surveillance of ALTs in citrus-based products, both domestic and imported, is required to obtain more scientific data for the determination of the maximum allowable concentrations of ALTs in China.

Characterization of isomeric lipid A species from Pseudomonas aeruginosa PAO1 by non-aqueous capillary electrophoresis with positive and negative ion electrospray tandem mass spectrometry

Pseudomonas aeruginosa is a priority target pathogen for antibiotic research and development because of its high resistance to a wide range of antibiotics. Acquisition of resistance is sometimes associated with modifications of the lipid A component present in the outer membrane of most Gram-negative bacteria. For a deeper understanding of subtle chemical variations of lipid A in relation to biological properties, the structural elucidation of lipid A species within a bacterial strain is of crucial importance. However, the simultaneous presence of monophosphorylated positional isomers in naturally heterogeneous lipid A samples cannot easily be recognized with direct MS measurements or with conventional LC-MS strategies. Herein, we present the application of a non-aqueous capillary electrophoresis (NACE) method coupled to positive and negative ion electrospray tandem mass spectrometry with collision-induced dissociation (CID) activation technique for the in-depth analysis of the lipid A isolate of P. aeruginosa PAO1. The main advantage of our NACE strategy is its separation power regarding the site of phosphorylation of the lipid A structures, which makes it a good orthogonal technique to chromatographic characterizations of the bacterial lipid A composition, where the separation is mainly based on acylation differences of the species. Overall, the results of this electrophoretic approach revealed hitherto unreported isomeric monophosphorylated PAO1 lipid A constituents, including both phosphate and acyl chain positional isomers. The parallel fragmentation in the complementary positive and negative ion modes enabled the unequivocal assignment of the phosphorylation site and position of acyl chains in lipid A compounds of three acylation families ranging from tetra- to hexa-acylation. Moreover, C1-monophosphorylated lipid A species have been identified in P. aeruginosa for the first time.

Pharmacological inhibition of FGFR by infigratinib reduces lipids associated with neurodegeneration in MOG35-55-induced EAE (P2-3.014)

<h3>Objective:</h3> To characterize the effects of pharmacological FGFR inhibition on lipids associated with neurodegeneration in EAE. <h3>Background:</h3> Analysis of human brain tissue has shown that FGF and FGFR modulate the pathogenesis of multiple sclerosis (MS). Expression of lipids associated with neuronal degeneration is changed in the CSF of patients. The lipids, ceramide and LPC are associated with axonal damage, demyelination, and vascular leakage. Clinical trials have found that FGF-based drugs have beneficial effects on the lipid metabolism. We hypothesized that pharmacological FGFR inhibition reduces the expression of lipids in EAE. <h3>Design/Methods:</h3> The selective FGFR inhibitor infigratinib (30 mg/kg) was administered orally over 10 days either from the time of EAE induction (prevention experiment) or onset of symptoms (suppression experiment) in MOG_35-55-induced EAE. At the peak of disease (days 18–20 p.i.) and the chronic phase of EAE (days 41–42 p.i.) lipids were analyzed by electrospray ionization-tandem mass spectrometry (ESI-MS), and myelin proteins by western blot in the spinal cord. <h3>Results:</h3> In the prevention experiment, application of infigratinib resulted in a reduction of LPC (p = 0.05) and ceramide concentrations (p = 0.01), and increased the expression of CNPase, MBP and PLP (p = 0.01) in the chronic phase. No effects on these lipids or myelin proteins were observed in the acute phase. In the suppression experiment, administration of infigratinib did not affect the concentrations of LPC or ceramide. The expression of MBP and PLP was upregulated in the acute phase (p = 0.01). <h3>Conclusions:</h3> Pharmacological inhibition of FGFR from the time of EAE induction resulted in a downregulation of lipids associated with neurodegeneration and enhanced myelin protein expression in the chronic phase of EAE, where neurodegeneration prevails. The underlying mechanisms of inhibition mediated lipid alterations are unclear. Inhibition of FGFR may have the potential to reduce lipid-associated neurodegeneration in EAE and MS. <b>Disclosure:</b> Dr. Berghoff has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Biogen Idec. Dr. Berghoff has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Roche. Dr. Berghoff has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Janssen. Dr. Berghoff has received personal compensation in the range of $500-$4,999 for serving as a Consultant for MerckSerono. Dr. Berghoff has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Bristol Myers Squibb. Natascha Wallendszus has nothing to disclose. Mr. Rajendran has nothing to disclose. Dr. Liebisch has nothing to disclose. Srikanth Karnati has nothing to disclose. Mr. Rajendran has nothing to disclose.

Positive Effect of Acetylation on Proteomic Analysis Based on Liquid Chromatography with Atmospheric Pressure Chemical Ionization and Photoionization Mass Spectrometry.

A typical bottom-up proteomic workflow comprises sample digestion with trypsin, separation of the hydrolysate using reversed-phase HPLC, and detection of peptides via electrospray ionization (ESI) tandem mass spectrometry. Despite the advantages and wide usage of protein identification and quantification, the procedure has limitations. Some domains or parts of the proteins may remain inadequately described due to inefficient detection of certain peptides. This study presents an alternative approach based on sample acetylation and mass spectrometry with atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI). These ionizations allowed for improved detection of acetylated peptides obtained via chymotrypsin or glutamyl peptidase I (Glu-C) digestion. APCI and APPI spectra of acetylated peptides often provided sequence information already at the full scan level, while fragmentation spectra of protonated molecules and sodium adducts were easy to interpret. As demonstrated for bovine serum albumin, acetylation improved proteomic analysis. Compared to ESI, gas-phase ionizations APCI and APPI made it possible to detect more peptides and provide better sequence coverages in most cases. Importantly, APCI and APPI detected many peptides which passed unnoticed in the ESI source. Therefore, analytical methods based on chymotrypsin or Glu-C digestion, acetylation, and APPI or APCI provide data complementary to classical bottom-up proteomics.

Design of high-monounsaturated fatty acid soybean seed oil using GmPDCTs knockout via a CRISPR-Cas9 system.

Design of high-monounsaturated fatty acid soybean seed oil using GmPDCTs knockout via a CRISPR-Cas9 system.

Preparation and Anti-Lung Cancer Activity Analysis of Guaiacyl-Type Dehydrogenation Polymer.

In this paper, guaiacyl dehydrogenated lignin polymer (G-DHP) was synthesized using coniferin as a substrate in the presence of β-glucosidase and laccase. Carbon-13 nuclear magnetic resonance (13C-NMR) determination revealed that the structure of G-DHP was relatively similar to that of ginkgo milled wood lignin (MWL), with both containing β-O-4, β-5, β-1, β-β, and 5-5 substructures. G-DHP fractions with different molecular weights were obtained by classification with different polar solvents. The bioactivity assay indicated that the ether-soluble fraction (DC2) showed the strongest inhibition of A549 lung cancer cells, with an IC50 of 181.46 ± 28.01 μg/mL. The DC2 fraction was further purified using medium-pressure liquid chromatography. Anti-cancer analysis revealed that the D4 and D5 compounds from DC2 had better anti-tumor activity, with IC50 values of 61.54 ± 17.10 μg/mL and 28.61 ± 8.52 μg/mL, respectively. Heating electrospray ionization tandem mass spectrometry (HESI-MS) results showed that both the D4 and D5 were β-5-linked dimers of coniferyl aldehyde, and the 13C-NMR and 1H-NMR analyses confirmed the structure of the D5. Together, these results indicate that the presence of an aldehyde group on the side chain of the phenylpropane unit of G-DHP enhances its anticancer activity.

Introducing direct probe electrospray ionization tandem mass spectrometry in apiculture: Comparison with other mass spectrometric methods for the determination of antibiotics in bees and honey

Amphenicols and tetracyclines (TCs) antibiotics use in apiculture is mainly focused on the treatment of bee brood diseases. Despite their efficiency, the serious genotoxic effects that some elicit led to their banning for use in apiculture and for chloramphenicol (CAP) in all food-producing animals. In this work, three tandem mass spectrometric methods were developed and validated for the analysis and quantification of CAP, thiamphenicol (TF), florfenicol (FF), tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) in honey and honeybees. With the first, we have demonstrated the first use of probe electrospray ionization (PESI) in conjunction with tandem mass spectrometry (MS/MS) for antibiotics determination in honey and bees entailing a minimum sample preparation for bees, resulting in rapid chemical analysis for both commodities. The second was a reversed-phase HPLC-ESI-MS/MS method sharing the same scope. With the third chiral HPLC-ESI-MS/MS method, it was attempted to separate CAP stereoisomers in both commodities since reports have shown that only the D-threo isomer displays antimicrobial properties. The analytical methods fulfilled validation criteria demonstrating recoveries in the range of 74–92%, managing to address the minimum required performance limit (MRPL) for CAP, with the exception of PESI-MS/MS. The latter displayed a detection capability (CCβ) for all compounds in proximity to 1 ng/g, and an overall runtime of 1.5 min. In total, 68 samples of honeybees and honey were evaluated for amphenicols and TCs residues. CAP was detected only in two honeybee samples, while one honey sample was positive to TC and OTC was detected in traces in another sample. PESI-MS/MS managed to quantify both TC in honey and CAP in bees in proximity to the values assigned by the conventional HPLC-ESI-MS/MS methods. With regard to the separation of CAP's isomers, the chiral method managed to resolute all isomers and quantify CAP in one bee sample in the form of its L-threo stereoisomer. Overall, ABCs detection in honey and related matrices still constitutes a challenge, considering their prevalence and potential applications in major honey-producing countries.

Differential protein response to different light quality conditions of industrial hemp cultivation based on DIA technology

Light quality plays a significant role in regulating plant growth, development, morphogenesis and physiological metabolism. Industrial hemp is a photophilic plant that is sensitive to light. Light quality directly affects the yield and quality of industrial hemp. In this study, ‘Yunma No.7′ was used as the experimental material, the light quality was regulated by a light-emitting diode (LED) light source, and Blue Light (BL) and Red Light (RL) with the best and worst promotional effects on growth, respectively, were set as the treatment conditions, with White Light (WL) used as a control. The physiological changes of industrial hemp under different light quality conditions were determined, and the protein stress mechanism of industrial hemp under different light quality conditions was analyzed using data-independent acquisition (DIA) proteomics technology. Through a liquid chromatography- electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) analysis, 456 and 421 differentially expressed proteins were identified under RL and BL, respectively. Through a Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, it was found that the differentially expressed proteins under RL and BL were significantly enriched in eight and four pathways, respectively. The growth of industrial hemp under BL(best light quality) was promoted mainly through the following mechanisms: enhancing the DNA repair capacity; synthesizing a large number of carotenoids to improve the photosynthetic rate; increasing the rate of auxin synthesis and starch accumulation; and accelerating lignification and plant nutrient absorption and utilization. The results provide a theoretical basis for light quality control in industrial hemp industrialization.

Optimising urinary catecholamine metabolite diagnostics for neuroblastoma.

The analysis of urinary catecholamine metabolites is a cornerstone of neuroblastoma diagnostics. Currently, there is no consensus regarding the sampling method, and variable combinations of catecholamine metabolites are being used. We investigated if spot urine samples can be reliably used for analysis of a panel of catecholamine metabolites for the diagnosis of neuroblastoma. Twenty-four-hour urine or spot urine samples were collected from patients with and without neuroblastoma at diagnosis. Homovanillic acid (HVA), vanillylmandelic acid (VMA), dopamine, 3-methoxytyramine, norepinephrine, normetanephrine, epinephrine and metanephrine were measured by high-performance liquid chromatography coupled with fluorescence detection (HPLC-FD) and/or ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry (UPLC-MS/MS). Catecholamine metabolite levels were measured in urine samples of 400 neuroblastoma patients (24-hour urine, n = 234; spot urine, n = 166) and 571 controls (all spot urine). Excretion levels of catecholamine metabolites and the diagnostic sensitivity for each metabolite were similar in 24-hour urine and spot urine samples (p > .08 and >.27 for all metabolites). The area under the receiver-operating-characteristic curve (AUC) of the panel containing all eight catecholamine metabolites was significantly higher compared to that of only HVA and VMA (AUC = 0.952 vs. 0.920, p = .02). No differences were observed in metabolite levels between the two analysis methods. Catecholamine metabolites in spot urine and 24-hour urine resulted in similar diagnostic sensitivities. The Catecholamine Working Group recommends the implementation of spot urine as standard of care. The panel of eight catecholamine metabolites has superior diagnostic accuracy over VMA and HVA.

Plasma lysosphingolipids in GRN-related diseases: Monitoring lysosomal dysfunction to track disease progression

GRN mutations are among the main genetic causes of frontotemporal dementia (FTD). Considering the progranulin involvement in lysosomal homeostasis, we aimed to evaluate if plasma lysosphingolipids (lysoSPL) are increased in GRN mutation carriers, and whether they might represent relevant fluid-based biomarkers in GRN-related diseases.We analyzed four lysoSPL levels in plasmas of 131 GRN carriers and 142 non-carriers, including healthy controls and patients with frontotemporal dementias (FTD) carrying a C9orf72 expansion or without any mutation. GRN carriers consisted of 102 heterozygous FTD patients (FTD-GRN), three homozygous patients with neuronal ceroid lipofuscinosis-11 (CLN-11) and 26 presymptomatic carriers (PS-GRN), the latter with longitudinal assessments. Glucosylsphingosin d18:1 (LGL1), lysosphingomyelins d18:1 and isoform 509 (LSM18:1, LSM509) and lysoglobotriaosylceramide (LGB3) were measured by electrospray ionization-tandem mass spectrometry coupled to ultraperformance liquid chromatography.Levels of LGL1, LSM18:1 and LSM509 were increased in GRN carriers compared to non-carriers (p < 0.0001). No lysoSPL increases were detected in FTD patients without GRN mutations. LGL1 and LSM18:1 progressively increased with age at sampling, and LGL1 with disease duration, in FTD-GRN. Among PS-GRN carriers, LSM18:1 and LGL1 significantly increased over 3.4-year follow-up. LGL1 levels were associated with increasing neurofilaments in presymptomatic carriers.This study evidences an age-dependent increase of β-glucocerebrosidase and acid sphingomyelinase substrates in GRN patients, with progressive changes as early as the presymptomatic phase. Among FTD patients, plasma lysoSPL appear to be uniquely elevated in GRN carriers, and thus might serve as suitable non-invasive disease-tracking biomarkers of progression, specific to the pathophysiological process. Finally, this study might add lysoSPL to the portfolio of fluid-based biomarkers, and pave the way to disease-modifying approaches based on lysosomal function rescue in GRN diseases.

Synthesis of 2-Ethyl-3-oxazolidineethanol from Propanal and Diethanolamine: Kinetic and Process Optimization Study

2-Ethyl-3-oxazolidineethanol (OE) is an important pharmaceutical intermediate for the treatment of dental plaque. A systematic investigation of the one-pot synthesis of OE from propanal (PA) and diethanolamine (DEA) was conducted herein. The process was carried out under mild reaction conditions without any addition of catalyst, and the product was characterized by Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance (NMR), and electrospray ionization-tandem mass spectrometry (ESI-MS/MS). Additionally, the effects of the PA/DEA ratio, methanol/DEA ratio, reaction time, and temperature on the reaction results were explored. Based on the single-factor experiments, response surface methodology (RSM) was used to optimize the reaction conditions and it achieved a high OE yield of 98.48%, which is close to the prediction value of 98.38%. Furthermore, the reaction kinetics were calculated utilizing the second-order kinetic model, and activation energies of the forward and reverse reactions were 31.35 and 41.85 kJ·mol–1, respectively. Under the optimization reaction conditions, OE was efficiently synthesized, indicating a significant potential for industrial applications.

Relationships between cause of death and concentrations of seven steroids obtained from the serum and cerebrospinal fluid of cadavers

In this study, we assessed 80 autopsy samples to investigate the relationships between cause of death and the concentrations of multiple steroids in serum and cerebrospinal fluid (CSF). First, we developed and validated analytical methods to quantify seven steroids (cortisol, cortisone, corticosterone, 11-deoxycortisol, 11-deoxycortiocosterone, progesterone, and testosterone) by using liquid chromatography coupled with electrospray ionization–tandem mass spectrometry. Next, we statistically evaluated the levels of each steroid for six causes of death: hypothermia, traumatic injury, fire fatality, asphyxia, intoxication, and internal disease. We observed that cortisol concentrations in serum and CSF obtained from cadavers who died from hypothermia were significantly higher than those in samples obtained from cadavers who died from the remaining causes of death (P < 0.05). Similarly, corticosterone concentrations obtained from cadavers who died from hypothermia were significantly higher than those in samples from several other causes of death. However, concentrations of the remaining steroids analyzed did not differ significantly among the causes of death. We further elucidated the correlations between steroid concentrations in serum and CSF. Except for 11-deoxycorticosterone and progesterone, steroid concentrations were significantly positively correlated in serum and CSF. Although data on cadaveric steroid concentrations are limited—especially in CSF—values obtained were in the approximate range of the living human data reported to date.

Optimization of black garlic production parameters using response surface methodology: Assessment and characterization of bioactive properties

This study was performed to determine the optimum process parameters for black garlic production. Central composite design (CCD) of the response surface methodology (RSM) was utilized to examine the effects of fermentation conditions (temperature, humidity and time) on the alliin, S-allyl cysteine (SAC), total phenolic content (TPC), antioxidant capacity, moisture, and 5-Hydroxymethylfurfural (HMF) contents of the black garlic samples. Liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry (LC-DAD-ESI-MS/MS) was used for the identification and quantification of alliin, SAC and HMF. SEM and FT-IR techniques were also utilized to characterize the samples. The optimized fermentation parameters were determined as 65 °C temperature, 85% humidity, and a duration of 24 days. TPC was found to be 1152.46 mg GAE/100 g dry matter with the highest antioxidant capacity while SAC and alliin contents were 80.21 and 5.16 mg/100 g, respectively. The HMF was quantified as 0.60 g/kg using the optimized parameters. It was also found that decreased temperature and fermentation time yielded a decrement in HMF and an increment in the bioactivity of black garlic.

Localization of cyclopropyl groups and alkenes within glycerophospholipids using gas-phase ion/ion chemistry.

Shotgun lipid analysis using electrospray ionization tandem mass spectrometry (ESI-MS/MS) is a common approach for the identification and characterization of glycerophohspholipids GPs. ESI-MS/MS, with the aid of collision-induced dissociation (CID), enables the characterization of GP species at the headgroup and fatty acyl sum compositional levels. However, important structural features that are often present, such as carbon-carbon double bond(s) and cyclopropane ring(s), can be difficult to determine. Here, we report the use of gas-phase charge inversion reactions that, in combination with CID, allow for more detailed structural elucidation of GPs. CID of a singly deprotonated GP, [GP - H]- , generates FA anions, [FA - H]- . The fatty acid anions can then react with doubly charged cationic magnesium tris-phenanthroline complex, [Mg(Phen)3 ]2+ , to form charge inverted complex cations of the form [FA - H + MgPhen2 ]+ . CID of the complex generates product ion spectral patterns that allow for the identification of carbon-carbon double bond position(s) as well as the sites of cyclopropyl position(s) in unsaturated lipids. This approach to determining both double bond and cyclopropane positions is demonstrated with GPs for the first time using standards and is applied to lipids extracted from Escherichia coli.

The Mechanism of Ochratoxin Contamination of Artificially Inoculated Licorice Roots.

Ochratoxin (OT) contamination of medicinal herbs is a serious threat to human health. This study was performed to investigate the mechanism of OT contamination of licorice (Glycyrrhiza sp.) root. Licorice root samples were cut into eight parts, which were placed separately on sucrose-free Czapek Dox agar medium, inoculated with the spores of ochratoxigenic Aspergillus westerdijkiae. After incubation for 10 and 20 days, the OT contents of the samples were determined by high-performance liquid chromatography, and microtome sections prepared from the samples were analyzed by desorption electrospray ionization tandem mass spectrometry, to visualize OT localization. The same sections were further examined by light microscopy and scanning electron microscopy, to investigate the path of fungal mycelial penetration of the inner roots. OT concentrations tended to increase from the upper- to the middle-root parts. OTs were located in cut areas and areas of cork layer damage; they were not present in the undamaged cork layer, indicating that the structure of this layer prevents OT contamination of the licorice root.

Proteomic Analysis in Valvular Cardiomyopathy: Aortic Regurgitation vs. Aortic Stenosis.

Left ventricular (LV) reverse remodeling after aortic valve (AV) surgery is less predictable in chronic aortic regurgitation (AR) than in aortic stenosis (AS). We aimed to disclose specific LV myocardial protein signatures possibly contributing to differential disease progression. Global protein profiling of LV myocardial samples excised from the subaortic interventricular septum in patients with isolated AR or AS undergoing AV surgery was performed using liquid chromatography-electrospray ionization-tandem mass spectrometry. Based on label-free quantitation protein intensities, a logistic regression model was calculated and adjusted for age, sex and protein concentration. Web-based functional enrichment analyses of phenotype-associated proteins were performed utilizing g:Profiler and STRING. Data are available via ProteomeXchange with identifier PXD039662. Lysates from 38 patients, including 25 AR and 13 AS samples, were analyzed. AR patients presented with significantly larger LV diameters and volumes (end-diastolic diameter: 61 (12) vs. 48 (13) mm, p < 0.001; end-diastolic volume: 180.0 (74.6) vs. 92.3 (78.4), p = 0.001). A total of 171 proteins were associated with patient phenotype: 117 were positively associated with AR and the enrichment of intracellular compartment proteins (i.e., assigned to carbohydrate and nucleotide metabolism, protein biosynthesis and the proteasome) was detected. Additionally, 54 were positively associated with AS and the enrichment of extracellular compartment proteins (i.e., assigned to the immune and hematopoietic system) was observed. In summary, functional enrichment analysis revealed specific AR- and AS-associated signatures of LV myocardial proteins.