Analysis Of Mass Spectra Research Articles

Aqueous production of secondary organic aerosol from fossil-fuel emissions in winter Beijing haze

Secondary organic aerosol (SOA) produced by atmospheric oxidation of primary emitted precursors is a major contributor to fine particulate matter (PM2.5) air pollution worldwide. Observations during winter haze pollution episodes in urban China show that most of this SOA originates from fossil-fuel combustion but the chemical mechanisms involved are unclear. Here we report field observations in a Beijing winter haze event that reveal fast aqueous-phase conversion of fossil-fuel primary organic aerosol (POA) to SOA at high relative humidity. Analyses of aerosol mass spectra and elemental ratios indicate that ring-breaking oxidation of POA aromatic species, leading to functionalization as carbonyls and carboxylic acids, may serve as the dominant mechanism for this SOA formation. A POA origin for SOA could explain why SOA has been decreasing over the 2013-2018 period in response to POA emission controls even as emissions of volatile organic compounds (VOCs) have remained flat.

Beneficial Anti-Platelet and Anti-Inflammatory Properties of Irish Apple Juice and Cider Bioactives.

Several bioactives from fruit juices and beverages like phenolics, nucleotides and polar lipids (PL) have exhibited anti-platelet cardio-protective properties. However, apple juice and cider lipid bioactives have not been evaluated so far. The aim of this study was to investigate the anti-platelet and anti-inflammatory effects and structure activity relationships of Irish apple juice and Real Irish cider lipid bioactives against the platelet-activating factor (PAF)- and adenosine diphosphate (ADP)-related thrombotic and inflammatory manifestations in human platelets. Total Lipids (TL) were extracted from low, moderate and high in tannins apple juices and from their derived-through-fermentation cider products, as well as from commercial apple juice and cider. These were separated into neutral lipids (NL) and PL, while all lipid extracts were further assessed for their ability to inhibit aggregation of human platelets induced by PAF and ADP. In all cases, PL exhibited the strongest anti-platelet bioactivities and were further separated by high-performance liquid chromatography (HPLC) analysis into PL subclasses/fractions that were also assessed for their antiplatelet potency. The PL from low in tannins apple juice exhibited the strongest antiplatelet effects against PAF and ADP, while PL from its fermented cider product were less active. Moreover, the phosphatidylcholines (PC) in apple juices and the phosphatidylethanolamines (PE) in apple ciders were the most bioactive HPLC-derived PL subclasses against PAF-induced platelet aggregation. Structural elucidation of the fatty acid composition by gas chromatography mass spectra (GCMS) analysis showed that PL from all samples are rich in beneficial monounsaturated fatty acids (MUFA) and omega 3 (n-3) polyunsaturated fatty acids (PUFA), providing a possible explanation for their strong anti-platelet properties, while the favorable low levels of their omega-6/omega-3 (n-6/n-3) PUFA ratio, especially for the bioactive PC and PE subclasses, further support an anti-inflammatory cardio-protective potency for these apple products. In conclusion, Irish apple juice and Real Irish cider were found to possess bioactive PL compounds with strong antiplatelet and anti-inflammatory properties, while fermentation seems to be an important modulating factor on their lipid content, structures and bioactivities. However, further studies are needed to evaluate these effects.

Wild edible fruit crop Haematocarpus validus (Miers) Bakh.f. ex Forman (Khoon phal): a novel source of nutraceuticals.

The online version contains supplementary material available at 10.1007/s13197-021-04997-7.

Evaluation of microchannel plate gain drops caused by high ion fluxes in time-of-flight mass spectrometry: A novel evaluation method using a multi-turn time-of-flight mass spectrometer.

Use of a two-stage microchannel plate (MCP) detector is common in time-of-flight (TOF) mass spectrometry because it shows excellent time resolution with sufficient gains. However, the gain drops significantly when the detector detects intense ion fluxes, such as matrix ions, by matrix-assisted laser desorption/ionization mass spectrometry. As a result, significant ion signals corresponding to analytes, such as proteins, are hidden, thereby hampering the mass spectral interpretation. However, details of this phenomenon have not previously been investigated using ions because of the lack of suitable measurement methods and apparatus. Thus, we herein report a novel method for controlling the TOF of two selected ions, as a function of time differences between each other using a multi-turn TOF mass spectrometer. This method involves the use of an isotope cluster of ions that fly in a figure-of-eight orbit and the extraction of an ion at a given lap number. A series of time differences (∆t) between two ions in a TOF spectrum can be generated using this method. We evaluated the time constants of gain recovery after high ion-flux detection for two sets of two-stage MCP detectors to obtain values of 1,600 and 180 μs for channel plate resistances of 500 and 71 MΩ, respectively. The obtained time constants from the gains determined at various values of ∆t were 0.48 and 0.38 fold (for 500 and 71 MΩ, respectively) of the values suggested from the channel plate resistance and capacitance.

Antimicrobial and cytotoxic activities of isoniazid connected menthone derivatives and their investigation of clinical pathogens causing infectious disease

BackgroundThis work is development of new molecules of isoniazid derivatives as dealing with potential of antimicrobial activity against clinical pathogens causing infectious disease. Antimicrobial of novel Mannich base derivatives can be achieved via one-pot synthesis in green chemistry approach. This method offers efficient, mild reaction conditions and high yields. In this study, totally 12 compounds (1a–l) was prepared and screened for cytotoxic and antimicrobial activities. Materials and methodsNewly synthesised compounds were conformed via FT- IR, 1H, and 13C NMR (Nuclear Magnetic Resonance), and mass spectra analysis. All compounds were checked antibacterial activity against gram-positive bacteria of Enterococcus faecalis, Staphylococcus aureus and gram-negative bacteria of Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli. All compounds were checked against antifungal activity against Aspergillus fumigatus, Candida albicans, Cryptococcus neoformans, Aspergillus niger, and Microsporum audouinii. All compounds were screened for cytotoxic activity against the MCF-7 (Michigan Cancer Foundation-7) cancer cell line. ResultThe compound 1g was highly (MIC: 0.25 μg/mL) active against gram-negative bacterial of P. aeruginosa, whereas other compounds 1e and 1h were more active (MIC: 2 μg/mL) in K. pneumoniae and also 1g (MIC: 2 μg/mL) was more active in E. faecalis than standard ciprofloxacin. Antifungal screening, the compound 1b was highly active (MIC: 0.25 μg/mL) against C. albicance,1g (MIC: 2 μg/mL) and 1h (MIC: 4 μg/mL) was significant of active against A. fumigatus, and the compound 1c (MIC: 4 μg/mL) was extremely active in M. audouinii than clotrimazole. Compound 1g (GI50 = 0.01 μM) exhibited high activity against the MCF-7 cell line, while 1b (GI50 = 0.02 μM) was equipotent active compared with standard doxorubicin. ConclusionA novel set of isoniazid derivatives (1a–l) and 1h were synthesized and screened for antimicrobial and cytotoxic activities. We found some highly active molecules, which are evidencing to be a potential treatment of bacterial and fungal infection candidates.

Evaluation of Bioactive Compound from Cashew Apple Juice by Gas Chromatography–Mass Spectrum Analysis

Evaluation of Bioactive Compound from Cashew Apple Juice by Gas Chromatography–Mass Spectrum Analysis

Spectral quality overrides software score―A brief tutorial on the analysis of peptide fragmentation data for mass spectrometry laymen

The Special Feature this month comes from Simone König, Interdisciplinary Center for Clinical Research, Medical Faculty, University of Münster, Germany. Her contribution serves both as a valuable guide to mass spectral interpretation - specifically peptide fragmentation, the basis of bottom-up proteomics - and as a cautionary note to all omics practitioners. Dr. König uses examples to highlight both the power and the potential pitfalls of automated omics strategies. She discusses what she describes as the potential for over-interpretation of mass spectral data when the user places undue confidence in the power of automated spectral software interpretation tools. Dr. König's tutorial reiterates an important take-away message multiple times, in various ways, and illustrates this message by numerous examples. Her message is simple: User beware! Omics methods combine powerful inline separation technologies, high throughput MS/MS spectral generation strategies, and automated data analysis/interpretation software to deliver what can only be described as an avalanche of data. But, without thoughtful consideration of each of the components and intelligent oversight of the whole process, regrettably, errors can abound.

Structural characterization and immunostimulatory activity in vitro of a glycogen from sea urchin–Strongylocentyotus internedius

Sea urchin possesses both high nutritional and medicinal value. It contains diverse biological active polysaccharides. But there are few studies on its glycogen. In the current study, a glucan (MSGA) was separated from Strongylocentyotus internedius and purified by ion exchange and gel filtration column. Chemical analysis revealed that MSGA with 2.65 × 107 Da is made up entirely of glucose. The analysis of methylation, NMR and mass spectrum demonstrated that MSGA is a highly branched glycogen with α-(1→4) linked gluconic backbone and branched at C-6 (one branch per five residues). In addition, MSGA showed good in vitro immunostimulatory activity via NF-κB and MAPKs pathways. It is considered that high degree of branching is necessary for its activity. However, the relationship between structure and immunostimulatory activity of natural glycogens is difficult to elucidate because the difference in their structural properties. Therefore, much more research is needed in this area.

Machine-learning-enhanced time-of-flight mass spectrometry analysis

SummaryMass spectrometry is a widespread approach used to work out what the constituents of a material are. Atoms and molecules are removed from the material and collected, and subsequently, a critical step is to infer their correct identities based on patterns formed in their mass-to-charge ratios and relative isotopic abundances. However, this identification step still mainly relies on individual users' expertise, making its standardization challenging, and hindering efficient data processing. Here, we introduce an approach that leverages modern machine learning technique to identify peak patterns in time-of-flight mass spectra within microseconds, outperforming human users without loss of accuracy. Our approach is cross-validated on mass spectra generated from different time-of-flight mass spectrometry (ToF-MS) techniques, offering the ToF-MS community an open-source, intelligent mass spectra analysis.

Synthesis, characterization and potent antimicrobial and antifungal activity of 2-substituted benzimidazole derivatives

Benzimidazole is the heterocyclic compound formed by the fusion of benzene and imidazole ring. Benzimidazole analogs are of great significance because of their clinical application and biological activity. Benzimidazoles are considered as an optimistic class of bioactive heterocyclic compound that possesses a range of biological activities. We have synthesized five substituted Benzimidazole derivative using on both microwave irradiation and conventional heating method. The newly synthesized compounds are characterized by IR, NMR and Mass spectra analysis. In the present study, we have reported the synthesis, spectral studies and biological evaluation of some benzimidazole derivatives. Benzimidazole play important role in medical field with so many pharmacological activities such as antimicrobial, anti bacterial, etc. The potency of this clinically useful drug in treatment in microbial action and other activities has encouraged the development of some more potent and significant compounds.

Isolation and Characterization of Anti Psychotic Compound From Cassia Occidentalis Leaf

The aim of the current work was mainly to find the neuroleptic effects of responsible compounds isolated from Cassia occidentalis leaves, on condiontioning avoidance and catalepsy induced psychotic wistar rats. Psychosis was induced by condiontioning avoidance and catalepsy induced in albino wistar rats. An isolated fraction of the ethanolic extract of Cassia occidentalis was ingested orally at 100 mg/kg, p.o dose. Haloperidol was considered as standard neuroleptic drug (10 mg/kg, p.o.). The isolated fractions from the column chromatography showing for the higher neuroleptic activity that facilitated for isolating the pure constituent, that was named trivially as name CO- 1.Precise analysis of the previous investigations with Ethanolic extract of Cassia occidentalis (ETCO) have encouraged us to isolate anti-psychotic responsible consituents from the leaves of Cassia occidentalis for managing the anti-psychotic activity. Collected pooled fractions were subjected to anti-psychotic activity in conditioning avoidance and catalepsy induced wistar rats. The fraction F from ETCO showed strong neuroleptic activity when compared with the commercial standard drug Haloperidol. To propose the constituents that possess anti psychotic activity related to F respectively. Besides, column chromatography analysis was performed with ‘F’ using different solvents and the isolated compound which is named as CO-1. This amorphous powder was extracted from the column with decomposition point. CO-1 is a phenolic compound that was confirmed by IR, Mass Spectrum and NMR analysis.

An easy access to highly substituted trispiroheterocycles – Synthesis of novel pyrazolo-1,4-dioxa-spiro[4,5]decane grafted spiro-oxindolopyrrolidines via a sequential multicomponent reaction

A facile one-pot sequential four-component synthesis of highly substituted trispiro heterocyclic system involving [3 + 2]-cycloaddition of azomethine ylides as the key step is described. The protocol provides a mild reaction condition, high yield of the products, high regioselectivity, and operational simplicity to assemble complex structural entity in a single operation. The structure of the product was confirmed by spectroscopic techniques, elemental and high-resolution mass spectrum analysis.

Tumor suppressor DRD2 facilitates M1 macrophages and restricts NF-κB signaling to trigger pyroptosis in breast cancer.

Rationale: Breast cancer (BrCa) is the most common cancer worldwide, and the 5-year relative survival rate has declined in patients diagnosed at stage IV. Advanced BrCa is considered as incurable, which still lack effective treatment strategies. Identifying and characterizing new tumor suppression genes is important to establish effective prognostic biomarkers or therapeutic targets for late-stage BrCa.Methods: RNA-seq was applied in BrCa tissues and normal breast tissues. Through analyzing differentially expressed genes, DRD2 was selected for further analysis. And expression and promoter methylation status of DRD2 were also determined. DRD2 functions were analyzed by various cell biology assays in vitro. Subcutaneous tumor model was used to explore DRD2 effects in vivo. A co-cultivated system was constructed to investigate interactions of DRD2 and macrophages in vitro. WB, IHC, IF, TUNEL, qRT-PCR, Co-IP, Antibody Array, and Mass Spectrum analysis were further applied to determine the detailed mechanism.Results: In BrCa, DRD2 was found to be downregulated due to promoter methylation. Higher expression of DRD2 positively correlated with longer survival times especially in HER2-positive patients. DRD2 also promoted BrCa cells sensitivity to Paclitaxel. Ectopic expression of DRD2 significantly inhibited BrCa tumorigenesis. DRD2 also induced apoptosis as well as necroptosis in vitro and in vivo. DRD2 restricted NF-κB signaling pathway activation through interacting with β-arrestin2, DDX5 and eEF1A2. Interestingly, DRD2 also regulated microenvironment as it facilitated M1 polarization of macrophages, and triggered GSDME-executed pyroptosis.Conclusion: Collectively, this study novelly manifests the role of DRD2 in suppressing BrCa tumorigenesis, predicting prognosis and treatment response. And this study further reveals the critical role of DRD2 in educating M1 macrophages, restricting NF-κB signaling pathway and triggering different processes of programmed cell death in BrCa. Taking together, those findings represent a predictive and therapeutic target for BrCa.

Computational docking and in vitro analysis identifies novel arylidene analogue FPMXY-14 against renal cancer cells by attenuating Akt.

Targeted therapies are gaining global attention to tackle Renal Cancer (RC). This study aims to screen FPMXY-14 (novel arylidene analogue) for Akt inhibition by computational and in vitro methods. FPMXY-14 was subjected to proton NMR analysis and Mass spectrum analysis. Vero, HEK-293, Caki-1, and A498 cell lines were used. Akt enzyme inhibition was studied with the fluorescent-based kit assay. Modeller 9.19, Schrodinger 2018-1, LigPrep module, and Glide docking were used in computational analysis. The nuclear status was assessed by PI/Hoechst-333258 staining, cell cycle, and apoptosis assays were performed using flow cytometry. Scratch wound and migrations assays were performed. Western blotting was applied to study key signalling proteins. FPMXY-14 selectively inhibited kidney cancer cell proliferation with GI50 values of 77.5 nM and 101.40 nM in Caki-1 cells and A-498 cells, respectively. The compound dose-dependently inhibited Akt enzyme with an IC50 value of 148.5 nM and bound efficiently at the allosteric pocking of the Akt when computationally analyzed. FPMXY-14 caused nuclear condensation/fragmentation, increased the sub G0/G1, G2M populations, and induced early, late phase apoptosis in both cells when compared to controls. Treatment of the compound inhibited wound healing and migration of tumor cells, while proteins like Bcl-2, Bax, and caspase 3 were also altered. FPMXY-14 effectively inhibited the phosphorylation of Akt in these cancer cells, while total Akt was unaltered. FPMXY-14 exhibited anti-proliferative and anti-metastatic activities in kidney cancer cells by attenuating the Akt enzyme. Further pre-clinical research on animals with a detailed pathway elucidation is recommended.

LC/ESI-MS analysis of underivatized short-chain peptides and mass spectrum

LC/ESI-MS analysis of underivatized short-chain peptides and mass spectrum

Primary Volatile Aroma Compounds in Phka Rumduol, Cambodia

Phka Rumduol is a leading variety in Cambodian rice. Analysis and qualification of volatile aroma compounds of Cambodian rice were not reported yet, limiting a few papers about only 2-acetyl-1-pyrroline (2-AP). Although Cambodia has been very impressive and progressed for milling rice exports over the last 10 years, rice qualities in her value chain are still remained much more improvement, especially in domestic market. In this paper, volatile aroma compounds in Phka Rumduol (brown rice), cultivated by Cambodian Agricultural Research and Development Institute (CARDI) was analyzed by gas chromatograph mass spectrum (GCMS) and aroma extract dilution analysis (AEDA). As the results, 2-AP and other 21 aroma compounds were detected. Its flavor dilution (FD) factor of 2-AP was extremely high at 10,000. Since 2-AP was dominant aroma in Phka Rumduol, the analytical measure of 2-AP by solid phase micro extraction (SPME) and gas chromatograph (GC) in rice kernels were investigated. With the purpose to compare qualities between Phka Rumduol (CARDI) and Phka Rumduol purchased in a Cambodian market (commercial), 2-AP concentration of both samples, the changes of 2-AP by different milling degrees, using both samples and 2-AP concentration in red kernels in commercial were analyzed. The results showed that 2-AP of Phka Rumduol (CARDI) and Phka Rumduol (commercial) were 800 and 380 ppb respectively, that after 0, 1, 2, 3 and 4 minutes-milling, the 2-AP in CARDI ranged in 800 to 420 ppb, while commercial did in 380 to 250 ppb and that 2-AP of whole red kernels in commercial was 50 ppb. From the results changes of milling time, 2-AP was located more in out-layer than inside of rice kernel. Phka Rumduol (CARDI) was very good qualities, while Phka Rumduol (commercial) showed less 2-AP concentration with larger percentages of broken, red kernels and lower qualified kernels like immature, chalky, damaged ones etc. Aroma which is one of important factors for Cambodian consumers will be decreased by rice type and grade of processing in market. This paper also referred a little to decrease in qualities by excess milling and/or polishing.

Metabolomics approach based on LC-HRMS for the fast screening of iron(II)-chelating peptides in protein hydrolysates.

Production of iron-chelating peptides from protein hydrolysates requires robust and adequate screening methods to optimize their purification and subsequently valorize their potential antioxidant properties. An original methodology was developed for direct and sensitive screening of iron(II)-chelating peptides based on ion-pair reverse phase liquid chromatography (IP-RPLC) coupled to high-resolution mass spectrometry (HRMS). Peptide mixture was first added to iron(II) solution to form iron(II)-peptide complexes. Then IP-RPLC-HRMS analysis was conducted on this iron-peptide mixture and on the iron-free peptide solution for comparative mass spectra analysis. This protocol, initially applied to a range of low molecular weight standard peptides, allowed detection of [(Peptide-H)+56FeII]+ complex ion for iron(II)-chelating peptides (GGH, EAH, DAH, βAH, DMH, DTH, DSH). GGH was added in complex peptide mixtures and targeted analysis of [(GGH-H)+56FeII]+ complex showed a limit of detection (LOD) below 0.77mgL-1 of GGH. This protocol was finally tested in combination with metabolomics software and additional digital processing for non-targeted search for iron(II)-chelating peptides. Applicability of this new screening methodology has been validated by detection of GGH as iron(II)-chelating peptide when added at 0.77mgL-1 in casein hydrolysate. Graphical abstract.

Extracellular Vesicles from Mycoplasmas Can Penetrate Eukaryotic Cells In Vitro and Modulate the Cellular Proteome.

The extracellular vesicles (EVs) produced by bacteria transport a wide range of compounds, including proteins, DNA and RNA, mediate intercellular interactions, and may be important participants in the mechanisms underlying the persistence of infectious agents. This study focuses on testing the hypothesis that the EVs of mycoplasmas, the smallest prokaryotes capable of independent reproduction, combined in the class referred to as Mollicutes, can penetrate into eukaryotic cells and modulate their immunoreactivity. To verify this hypothesis, for the first time, studies of in vitro interaction between human skin fibroblasts and vesicles isolated from Acholeplasma laidlawii (the ubiquitous mycoplasma that infects higher eukaryotes and is the main contaminant of cell cultures and vaccines) were conducted using confocal laser scanning microscopy and proteome profiling, employing a combination of 2D-DIGE and MALDI-TOF/TOF, the Mascot mass-spectrum analysis software and the DAVID functional annotation tool. These studies have revealed for the first time that the extracellular vesicles of A. laidlawii can penetrate into eukaryotic cells in vitro and modulate the expression of cellular proteins. The molecular mechanisms behind the interaction of mycoplasma vesicles with eukaryotic cells and the contribution of the respective nanostructures to the molecular machinery of cellular permissiveness still remain to be elucidated. The study of these aspects is relevant both for fundamental research into the "logic of life" of the simplest prokaryotes, and the practical development of efficient control over hypermutable bacteria infecting humans, animals and plants, as well as contaminating cell cultures and vaccines.

Ultrasound aided heterogeneous Fenton degradation of Acid Blue 15 over green synthesized magnetite nanoparticles

Magnetite nanoparticles were synthesized by bio-reduction method using neem leaf extract and its structural, morphological, chemical and magnetic characteristics were examined. The characteristic peaks obtained at 30.17°, 35.62°, 43.22°, 53.73°, 57.16° and 62.87° in the X-ray diffraction pattern (XRD) confirmed the formation of magnetite nanoparticles. Batch experiments were conducted to examine the efficiency of magnetite nanoparticles for degradation of the dye, Acid Blue 15 (AB15) by Fenton and ultrasound aided Fenton process. The results revealed enhanced dye removal in ultrasound aided Fenton mode when compared to Fenton process as degradation was attained within 20 min of contact time in the former process. Further, operational parameters on ultrasound aided Fenton degradation of AB 15 were optimized. Total organic carbon (TOC) removal efficiency and dye removal efficiency obtained was 40.4% and 99.3%, respectively at an optimum condition of pH 3, catalyst dosage 1 g L-1, H2O2 dosage 10 mM, and initial AB15 dye concentration of 100 mg L-1. Leached iron concentration at the end of the reaction was determined to be 0.60 mg L-1. The catalyst possesses good stability as it exhibited good performance over 3 cycles. The involvement of hydroxyl radicals in the degradation was confirmed by conducting experiments using radical scavengers. Gas chromatography mass spectrum (GC–MS) analysis revealed the formation of 4-((4-ammoniocyclohexa-2,5-dien-1-ylidene)(phenyl)methyl)aniline, N-ethyl-N-methylethanamine and 3- methylbenzenesulfonate as by-products of ultrasound aided Fenton process. Hence, ultrasound aided Fenton process is a promising method to degrade organic pollutants in wastewater.

Identification and characterization of serum albumin covalent adduct formed with atrazine by liquid chromatography mass spectrometry

The present study developed an analytical technique to investigate the possible covalent adduct formation of albumin with the herbicide atrazine, and to characterize the protein modifications in vitro using liquid chromatography separation coupled with high resolution time-of-flight mass spectrometry (LC-TOF-MS). Tandem mass spectrum analysis (MS/MS) with collision induced dissociation (CID) revealed the specific sites of rat, human and bovine serum albumin adduct with atrazine. The formation of b-ion, y-ion series in MS/MS showed a covalent adduct with an addition mass of 179.1 Da located on Cys-34 of serum albumin from rats, human and bovine. This clearly indicated that the chemical group C8H13N5 forms an adduct with Cys-34 despite the sequences differences between of rat, human and bovine serum albumin. To confirm the method reliability, concentration-dependent and time-dependent formation of adducts between serum albumins and atrazine were also investigated. Our results confirmed that atrazine can directly react with Cys-34 of serum albumin and form covalent adducts without prior metabolism.