High-resolution Mass Spectrometry Analysis Research Articles

Mn(III)-mediated bisphenol a degradation: Mechanisms and products

Bisphenol A (BPA) is a high production volume chemical with potential estrogenic effects susceptible to abiotic degradation by MnO2. BPA transformation products and reaction mechanisms with MnO2 have been investigated, but detailed process understanding of Mn(III)-mediated degradation has not been attained. Rapid consumption of BPA occurred in batch reaction vessels with 1 mM Mn(III) and 63.9 ± 0.7% of 1.76 ± 0.02 μmol BPA was degraded in 1 hour at circumneutral pH. BPA was consumed at 1.86 ± 0.09-fold higher rates in vessels with synthetic MnO2 comprising approximately 13 mol% surface-associated Mn(III) versus surface-Mn(III)-free MnO2, and 10–35% of BPA transformation could be attributed to Mn(III) during the initial 10-min reaction phase. High-resolution tandem mass spectrometry (HRMS/MS) analysis detected eight transformation intermediates in reactions with Mn(III), and quantum calculations proposed 14 BPA degradation products, nine of which had not been observed during MnO2-mediated BPA degradation, suggesting mechanistic differences between Mn(III)- versus MnO2-mediated BPA degradation. The findings demonstrate that both Mn(III) and Mn(IV) can effectively degrade BPA and indicate that surface-associated Mn(III) increases the reactivity of synthetic MnO2, offering opportunities for engineering more reactive oxidized Mn species for BPA removal.

Deoxygenative Cross-Coupling of C(aryl)–O and C(amide)═O Electrophiles Enabled by Chromium Catalysis Using Bipyridine Ligand

Deoxygenative cross-coupling between unactivated C–O and unsaturated C═O electrophiles remains an unsolved challenge in synthetic chemistry. Here, we report the deoxygenative cross-coupling of C–O/C═O electrophiles by reaction of unactivated aryl esters with unsaturated amides, enabled by chromium catalysis. Inexpensive and simple CrCl3 salt combined with bipyridine ligand, magnesium reductant, and chlorosilane, shows high reactivity in promoting the deoxygenative coupling between C–O and C═O bonds involving hydrogen transfer. This reaction provides a strategy to form pharmaceutically interesting diarylmethylated amines, by forging C(sp2)–C(sp3) bonds with impeding the competing ester homocoupling and carbonyl reduction that usually occur under reductive conditions. Mechanistic studies based on high-resolution mass spectrometry analysis and deuterium-labeling experiments indicate that cleavage of ester C–O bonds by Cr and subsequent silylation leads to the formation of arylated silachromate, which regioselectively adds to carbonyls of amides through reductive elimination and deoxygenative hydrogen transfer, resulting in the reductive cross-coupling of C(aryl)–O and C(amide)═O electrophiles.

Self-assembly of Cu-TMA based semiconducting fibrous metallogels for fabrication of active electronic device with high rectification ratio

A stable supramolecular Cu-TMA metallogel was synthesized by using Copper (II) acetate monohydrate and trimesic acid (TMA) as a low molecular weight organic gelator in DMF. The rheological studies confirmed that the synthesized Cu-TMA metallogels have high storage modular. The FT-IR (Fourier-transform infrared spectroscopy) and HR-MS (High Resolution Mass Spectrometry) analysis confirmed the metal–ligand aggregation in the produced metallogels. Apart, FESEM (Field Emission Scanning Electron Microscopy) and TEM (Transmission electron microscopy) probed the shape and morphology of the synthesized supramolecular metallogel like self-assembled fibrous like structure. However, TGA analysis confirmed the high thermal stability of metallogel. To explore the semiconducting properties of metallogel we calculate the energy band gap and, other electrical properties such as current–voltage characteristics and rectifying behaviour for metal–semiconductor (MS) junction-device have been properly investigated. In addition to this, based on the non-linear rectifying behaviour of the device, we have fabricated an active electronic device a Schottky Diode having high Rectification (Ion/Ioff) ratio. Consequently, our synthesized semiconducting Cu-TMA metallogel is fruitful and efficient and could be applied for various other optoelectronic devices in future.

Evaluation of Antiproliferative, Antimicrobial, Antioxidant, Antidiabetic and Phytochemical Analysis of Anogeissus dhofarica A. J. Scott

In the current study, methanol (ADAM) extracts and their fractions, including chloroform (ADAC), ethyl acetate (ADAE), n-hexane (ADAH), and aqueous (ADAA) fractions, were prepared from aerial parts of Anogeissus dhofarica and evaluated for phytochemical assessment, high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) analysis, and in vitro bioassays. The qualitative analysis determined that, except alkaloids, all the representative groups were found to be present in the analyzed samples. Samples under quantitative study displayed the highest amount of total phenolic contents in the ADAE fraction, while total flavonoid contents were highest in the ADAM extract. The ADAM extract was subjected to HR-ESI-MS to identify the chemical constituents that presented twenty-two bioactive ingredients, outlined for the first time from A. dhofarica, mainly contributed by sub-class flavanones. In the case of antimicrobial activity, the ADAE extract revealed an effective zone of inhibition (ZOI) against the Gram-positive bacterial strain (Staphylococcus aureus) with an MIC value of 0.78 ± 0.3 mg/mL, while the ADAA extract exhibited higher ZOI (34 ± 0.12 mm) against the fungal strain Candida kruzei with an MIC of 0.78 mg/mL. In the DPPH (2,2-diphenyl-1-picrylhydrazyl) analysis, the ADAE extract exhibited a maximum scavenging potential with an IC50 of 9.8 ± 1.2 μg/mL, succeeded by the ADAM extract with an IC50 of 17.4 ± 0.4 μg/mL free radical scavenging capability. In the antidiabetic assessment, the ADAE extract was the most effective, with an IC50 of 6.40 ± 0.1 μg/mL, while the same extract demonstrated prominent activity with 30.8% viability and an IC50 of 6.2 ± 0.3 μg/mL against breast cancer cell lines. The brine shrimp lethality assay demonstrated a correlation with the in vitro cytotoxicity assay, showing the ADAE extract as the most active, with a 70% mortality rate and an LC50 of 300.1 μg/mL. In conclusion, all the tested samples, especially the ADAE and ADAM extracts, have significant capabilities for the investigated activities that could be due to the presence of the bioactive compounds.

Secretions from Serratia marcescens Inhibit the Growth and Biofilm Formation of Candida spp. and Cryptococcus neoformans.

Candida spp. and Cryptococcus are conditional pathogenic fungi that commonly infect immunocompromised patients. Over the past few decades, the increase in antifungal resistance has prompted the development of new antifungal agents. In this study, we explored the potential antifungal effects of secretions from Serratia marcescens on Candida spp. and Cryptococcus neoformans. We confirmed that the supernatant of S. marcescens inhibited fungal growth, suppressed hyphal and biofilm formation, and downregulated the expression of hyphae-specific genes and virulence-related genes in Candida spp. and C. neoformans. Furthermore, the S. marcescens supernatant retained biological stability after heat, pH, and protease K treatment. The chemical profile of the S. marcescens supernatant was characterized by ultra-high-performance liquid chromatography-linear ion trap/orbitrap high resolution mass spectrometry analysis and a total of 61 compounds with an mzCloud best match of greater than 70 were identified. In vivo, treatment with the S. marcescens supernatant reduced the mortality of fungi-infected Galleria mellonella. Taken together, our results revealed that the stable antifungal substances in the supernatant of S. marcescens have promising potential applications in the development of new antifungal agents.

Identification of Quorum Quenching N-Acyl Homoserine Lactonases from Priestia aryabhattai J1D and Bacillus cereus G Isolated from the Rhizosphere

Several pathogenic bacteria communicate using N-acyl homoserine lactone (AHL) as a quorum sensing (QS) molecule. The process of interfering with the QS system is known as quorum quenching (QQ), it is an effective tool to control QS-dependent virulence in pathogens. In the present study, rhizosphere bacterial isolates were screened for their ability to produce AHL lactonase enzyme as QQ molecules, which hydrolyses AHL signalling molecules and consequently blocks the QS system. Potent N-hexanoyl-l-homoserine lactone (C6HSL) hydrolytic QQ activity was detected in rhizosphere isolates namely Bacillus cereus G and Priestia aryabhattai J1D. The cell-free supernatant of the bacterial isolates indicated a reduction in biofilm formation in the human pathogens Vibrio cholerae, Pseudomonas aeruginosa, and Staphylococcus aureus without inhibiting cells, signifying their biocontrol property. Furthermore, liquid chromatography high resolution mass spectrometry analysis confirmed C6HSL hydrolytic activity by AHL lactonase produced by these rhizosphere isolates. Also, the aiiA homologous gene from the bacterial isolates showed similarity with the aiiA lactonase gene from Bacillus species, which was further confirmed by homology modelling. In silico structure analysis by comparing with the structure of Bacillus revealed the similarity in the active site, indicating the same degradation pattern. Based on available reported data, the present study indicates the first report of the presence of the aiiA lactonase gene in P. aryabhattai.

Exploration of the Antioxidant and Anti-inflammatory Potential of Cassia sieberiana DC and Piliostigma thonningii (Schumach.) Milne-Redh, Traditionally Used in the Treatment of Hepatitis in the Hauts-Bassins Region of Burkina Faso.

Inflammation is the supreme biological response to illness. In the Hauts-Bassins region, in traditional medicine, all parts of Cassia sieberiana and Piliostigma thonningii are used to treat hepatitis and inflammation. The aim of this study was to evaluate the in vitro antioxidant and anti-inflammatory activities of their aqueous extracts. High performance liquid chromatography with photodiode array (HPLC-DAD) and ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-MS/MS) analyses highlighted the presence of polyphenols and flavonoids. Antioxidant and anti-inflammatory activities were measured by various methods such as DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), TAC (total antioxidant capacity), anti-protease, anti-lipoxygenase, and membrane stabilization. The best antioxidant activity was observed in the bark (DPPH: IC50 = 13.45 ± 0.10 µg/mL) and roots (TAC = 29.68 ± 1.48 mg AAE/g DW) of Piliostigma thonningii and in the roots (ABTS: IC50 = 1.83 ± 0.34 µg/mL) of Cassia sieberiana. The best anti-inflammatory activity was observed in the bark (anti-lipoxygenase: IC50 = 13.04 ± 1.99 µg/mL) and leaves (anti-proteases: IC50 = 75.74 ± 1.07 µg/mL, membrane stabilization: IC50 = 48.32 ± 6.39 µg/mL) of Cassia sieberiana. Total polyphenols (ABTS: r = -0.679, TAC: r = 0.960) and condensed tannins (ABTS: r = -0.702, TAC: r = 0.701) were strongly correlated with antioxidant activity. Total flavonoids (anti-proteases: r = -0.729), condensed tannins (anti-proteases: r = 0.698), and vitamin C (anti-proteases: r = -0.953) were strongly correlated with anti-inflammatory activity. Total polyphenols, flavonoids, condensed tannins, and vitamin C could contribute to the antioxidant and anti-inflammatory activities of the two studied plants. These results could validate the traditional use of these plants to treat various inflammatory diseases.

Chemical characterization of microplastic particles formed in airborne waste discharged from sewer pipe repairs.

Microplastic particles are of increasing environmental concern due to the widespread uncontrolled degradation of various commercial products made of plastic and their associated waste disposal. Recently, common technology used to repair sewer pipes was reported as one of the emission sources of airborne microplastics in urban areas. This research presents results of the multi-modal comprehensive chemical characterization of the microplastic particles related to waste discharged in the pipe repair process and compares particle composition with the components of uncured resin and cured plastic composite used in the process. Analysis of these materials employs complementary use of surface-enhanced Raman spectroscopy, scanning transmission X-ray spectro-microscopy, single particle mass spectrometry, and direct analysis in real-time high-resolution mass spectrometry. It is shown that the composition of the relatively large (100 μm) microplastic particles resembles components of plastic material used in the process. In contrast, the composition of the smaller (micrometer and sub-micrometer) particles is significantly different, suggesting their formation from unintended polymerization of water-soluble components occurring in drying droplets of the air-discharged waste. In addition, resin material type influences the composition of released microplastic particles. Results are further discussed to guide the detection and advanced characterization of airborne microplastics in future field and laboratory studies pertaining to sewer pipe repair technology.

Development of a kit for urine collection on filter paper as an alternative for Pompe disease screening and monitoring by LC-HRMS.

Pompe disease (PD) is an inborn error of metabolism caused by α-glucosidase acid enzyme deficiency. It significantly impacts patients' health and life quality and may lead to death in the first few years of life. Among the well-established diagnostic methods, urinary glucose tetrasaccharide (Glc4) screening by high performance-liquid chromatography has been helpful in monitoring Glc4 levels in patients on enzyme replacement therapy, demonstrating therapy efficacy. However, the specimen shipping process from a sample collecting location to a specialized laboratory for monitoring the Glc4 is costly and presents preanalytical challenges. In this work, we developed a filter paper based-urine collection kit to facilitate specimen shipment, and liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) analysis to determine Glc4 and creatinine in dried urine on filter paper. The LC-HRMS was based on a combination of targeted and untargeted screening on the same specimen injection and was successfully developed and validated. Bland-Altman statistics revealed a good relationship between dried and liquid urine samples and Glc4 and creatinine. Glc4 and other metabolites in dried urine showed stability for at least 7 days at 4 and 22 °C, and 3 days at 50 °C. The stability of the analytes and the efficiency of the kit were tested simulating real conditions by sending it by post. After two days in transit without refrigeration, the stability of compounds was maintained, showing the reliability of the urine collection kit and analysis method to determine the PD biomarker Glc4.

Imidacloprid degrading efficiency of Pseudomonas plecoglossicida MBSB-12 isolated from pesticide contaminated tea garden soil of Assam.

Long-term use of toxic pesticides in agricultural grounds has led to adverse effects on the environment and human health. Microbe-mediated biodegradation of pollutants is considered an effective strategy for the removal of contaminants in agricultural and environmental sustainability. Imidacloprid, a neonicotinoid class of pesticides, was widely applied insecticide in the control of pests in agricultural fields including the tea gardens of Assam. Here, native bacteria from imidacloprid contaminating tea garden soils were isolated and screened for imidacloprid degradation efficiency under laboratory conditions. Out of the 30 bacterial isolates, 4 were found to tolerate high concentrations of imidacloprid (25,000 ppm), one of which isolate MBSB-12 showed the highest efficiency for imidacloprid tolerance and utilization as the sole carbon source. Morphological, biochemical, and 16S ribosomal RNA gene sequencing-based characterization revealed the isolate as Pseudomonas plecoglossicida MBSB-12. The isolate reduced 87% of extractable imidacloprid from the treated soil in 90 days compared to the control soil (without bacterial treatment). High-Resolution Mass Spectrometry (HRMS) analysis indicated imidacloprid breakdown to comparatively less harmful products viz., imidacloprid guanidine olefin [m/z = 209.0510 (M + H)+], imidacloprid urea [m/z = 212.0502 (M + H)+] and a dechlorinated degraded product of imidacloprid with m/z value 175.0900 (M + H)+. Further investigation on the molecular machinery of P. plecoglossicida MBSB-12 involved in the degradation of imidacloprid is expected to provide a better understanding of the degradation pathway.

Farming for Pharming: Novel Hydroponic Process in Contained Environment for Efficient Pharma-Grade Production of Saffron.

Soilless cultivation of saffron (Crocus sativus) in a controlled environment represents an interesting alternative to field cultivation, in order to obtain a standardized high-quality product and to optimize yields. In particular, pharma-grade saffron is fundamental for therapeutic applications of this spice, whose efficacy has been demonstrated in the treatment of macular diseases, such as Age-related Macular Degeneration (AMD). In this work, a hydroponic cultivation system was developed, specifically designed to meet the needs of C. sativus plant. Various cultivation recipes, different in spectrum and intensity of lighting, temperature, photoperiod and irrigation, have been adopted to study their effect on saffron production. The experimentation involved the cultivation of corms from two subsequent farm years, to identify and validate the optimal conditions, both in terms of quantitative yield and as accumulation of bioactive metabolites, with particular reference to crocins and picrocrocin, which define the 'pharma-grade' quality of saffron. Through HPLC analysis and chromatography it was possible to identify the cultivation parameters suitable for the production of saffron with neuroprotective properties, evaluated by comparison with an ISO standard and the REPRON® procedure. Furthermore, the biochemical characterization was completed through NMR and high-resolution mass spectrometry analyses of saffron extracts. The whole experimental framework allowed to establish an optimized protocol to produce pharma-grade saffron, allowing up to 3.2 g/m2 harvest (i.e., more than three times higher than field production in optimal conditions), which meets the standards of composition for the therapy of AMD.

Long and Covalently Conjugated Branched DNA Structures for in Situ Gelation in Vivo

Long and Covalently Conjugated Branched DNA Structures for in Situ Gelation in Vivo

Construction of surface oxygen vacancies by bimetallic doping combined with ellagic acid modification to enhance the photocatalytic degradation of ethinyl estradiol by TiO2

In this paper, two surface oxygen vacancy-rich TiO2 composite photocatalysts were successfully constructed by solid thermal reduction ((R-Vo)TiO2) and bimetallic doping (Nd-Fe-(D-Vo)TiO2). The oxygen vacancies were characterized in detail using XPS, Raman, EPR and STEM. The results show that the excellent photocatalytic performance of Nd-Fe-(D-Vo)TiO2 deriving from its doping energy and surface oxygen vacancies. Nd-Fe-(D-Vo)TiO2 could degrade 58 % of phenol within 120 min, which was much greater than 15 % of TiO2 and 27 % of (R-Vo)TiO2. Three composite photocatalysts, TiO2@EA, (R-Vo)TiO2@EA and Nd-Fe-(D-Vo) TiO2@EA, with better visible light absorption and photocatalytic performance were further obtained by bonding ellagic acid (EA) to the surface of TiO2. Nd-Fe-(D-Vo)TiO2@EA could almost completely degrade ethinyl estradiol within 20 min with a high minimization degree of 84 %. The possible sites of ethinyl estradiol attacked by free radicals were predicted by theoretical calculation combining with high-resolution mass spectrometry analysis, and the possible degradation mechanism was proposed.

Tromancenium complexes with steric and electronic modulation

A series of new heteroleptic cationic (η7-cycloheptatrienyl)(η5-cyclopentadienyl)manganese(I) (“tromancenium”) sandwich complexes containing the cycloheptatrienyl ligand and various sterically bulky cyclopentadienyl ligands was synthesized in a one-pot two-step procedure via their cymantrene precursors by high-power LED photochemistry followed by oxidation. In comparison to their less-substituted congeners which display only partially reversible redox events, these new air-stable tromancenium salts show reversible Mn(I)/Mn(II) and quasi-reversible Mn(I)/Mn(0) redox couples, as intended by the conceptual design of this work. Full spectroscopic and structural characterization of by 1H, 13C, 55Mn NMR, IR, UV–vis spectroscopy, high-resolution mass spectrometry and single crystal structure analysis is reported.

Identification TDP‐43 fragments specific for frontotemporal lobar degeneration with TDP‐43 inclusions

AbstractBackgroundAnte‐mortem biomarkers specific for TDP‐43 pathology are highly desired given the challenge in distinguishing frontotemporal lobar degeneration with TDP‐43 pathology (FTLD‐TDP) from phenotypically related disorders. TDP‐43 post‐translational modifications, like C‐terminal fragments, are regarded as disease‐specific TDP‐43 proteoforms; however, the exact structure of these proteoforms remains unclear. This lack of clarity is due in part to the use of instrumentation and techniques with low structural resolution and the study of small sample sizes. With this in mind, we performed high resolution mass spectrometry (HRMS) analysis of brain tissue from cases with and without TDP‐43 proteinopathy to identify TDP‐43 proteoforms unique to FTLD‐TDP.MethodHRMS was used to determine TDP‐43 proteoform composition in insoluble frontal lobe brain tissue from immunohistochemically‐confirmed FTLD‐TDP (n=13), related dementias (i.e., Alzheimer’s disease and FTLD‐tau without TDP‐43 deposits; n=10) and neuropathologically‐unaffected controls (n=3). Brain tissue was fractioned by gel electrophoresis, with HRMS analysis performed on molecular weight regions corresponding to <28 kDa (low molecular weight TDP; L‐TDP), 28‐38 kDa (mid molecular weight TDP; M‐TDP), and 38‐55 kDa (intact TDP; I‐TDP).ResultIn all samples tested, the greatest TDP‐43 sequence coverage was observed for I‐TDP, followed by L‐TDP and then M‐TDP. TDP‐43 peptides from L‐TDP were more frequently detected in the FTLD‐TDP cases compared to both sets of controls, whereas no frequency differences were observed for I‐TDP and M‐TDP. Quantitative analysis revealed peptide concentrations from M‐ and L‐TDP were significantly increased in FTLD‐TDP cases compared to controls. The L‐TDP peptides concentrations differentiated FTLD‐TDP cases from related dementias and unaffected controls with 78% sensitivity and 100% specificity. Further, three in vivo cleavage sites of TDP‐43 were identified, which were unique to FTLD‐TDP cases.ConclusionThis is the largest reported proteomics study to date of histology‐confirmed FTLD‐TDP. This is also the first study to include a large number and range of control tissues, and to provide supporting evidence for in vivo cleavage sites including corroboration of the proteolytic fragment recently found in TDP‐43 fibrils. Clarity and consensus on the sequence of TDP‐43 disease‐specific proteoforms will be helpful in advancing biomarker and drug discovery efforts for TDP‐43 proteopathies.

Design, synthesis of bisbenzimidazole dithiol derivatives and analogs

The benzimidazole scaffold is an important pharmacophore and one of the preferred structures in medicinal chemistry due to the wide range of biological activities of its derivatives. Here in this article, the synthesis of two series of compounds, namely bis(thiobenzimidazol-2-yl)methane derivatives and analogs (4a-e) and bis(benzimidazol-2-yl)dithiol derivatives and analogs (5a-e) are described. These compounds were synthesized by first designing 2-mercaptobenzimidazole derivatives and analogs (2a-e) by action of orthophenylenediamine and analogs (1a-e) with carbon disulfide. Reaction of thiols (2a-e) with diiodomethane leads to bis(thiobenzimidazol-2-yl)methane derivatives and analogs (4a-e). Their treatment in glacial acetic acid led to their oxidation to bis(benzimidazol-2-yl)dithiol derivatives and analogs (5a-e). The structures of the synthesized compounds were characterized by 1H, 13C Nuclear Magnetic Resonance (NMR), and High-Resolution Mass Spectrometry (HRMS) analyses.

Rapid quantification of phenobarbital and barbital in human whole blood by liquid-liquid extraction combined with DART-orbitrap-HRMS.

This study aims to develop and validate a rapid, simple, and efficient bioanalytical method for the simultaneous quantification of phenobarbital and barbital in human whole blood using liquid-liquid extraction combined with direct analysis in real time (DART) and high-resolution mass spectrometry (HRMS). Phenobarbital-d5 and aprobarbital were selected as internal standards (ISs) of phenobarbital and barbital, respectively. A mixed solvent of o-xylene and ethyl acetate at a ratio of 1:6 was used to extract analytes of interest and ISs from 100 μL of human whole blood samples. Phenobarbital and barbital were detected by DART-HRMS. The proposed method has been validated in accordance with United States Food and Drug Administration Guidelines for Bioanalytical Method Validation in terms of selectivity, linearity, accuracy, precision, matrix effect, recovery, stability, and dilution integrity. The lower limits of quantification (LLOQs) of phenobarbital and barbital were both 10ng/mL. The linearities were in the range of 10-1000ng/mL (R2 ≥ 0.99). The mean recovery values of phenobarbital and barbital were 99.7% and 88.1%, respectively. The interday and intraday precision values were less than 10.4%, and the interday and intraday accuracy values ranged from 87.6 to 106.7%. Furthermore, the validated method was applied to four cases of phenobarbital poisoning at the Shanghai Institute of Forensic Science. The developed and fully validated method enabled the simultaneous quantification of phenobarbital and barbital in human whole blood and was successfully applied to authentic cases.

286 Oxidative Stress Modulation by Carnosine in Scaffold Free Human Dermis Spheroids Model: A Proteomic Study

Carnosine is an endogenous dipeptide with antioxidant and scavenger properties, shown to prevent aging and photoaging process by in vivo and in vitro models on different human tissues. Here an advanced quantitative proteomic approach (high-resolution mass spectrometry and network analyses) was applied to a 3D scaffold-free dermal spheroids model to investigate the biological responses induced by carnosine in human dermis. Primary human dermal fibroblasts from a 50-years-old donor were seeded in hanging drops to develop dermis spheroids.

Discovery of natural polyphenols from the wild vegetable Suaeda salsa L. with potential cardioprotective functions

Suaeda salsa L. (Chenopodiaceae) is a wild vegetable distributed along the northern coast of China. Searching for potential agents with health benefits from S. salsa L. led to the identification of 14 flavonoids (1–14), eight phenolic acids (15–22), one coumarin (23), one benzoquinone (24), two sesquiterpenes (25, 26), and three lignins (27–29) from an aqueous ethanol (EtOH) extract of the above-ground whole plant using various column chromatographic methods. High-resolution electrospray ionization mass spectrometry (HRESIMS) analyses and nuclear magnetic resonance (1H and 13C NMR) spectroscopy were adopted to examine the structural properties of the compounds. To date, our study is the first to identify 20 compounds from this genus. Some compounds exhibited significant health benefits in zebrafish models. Compounds 2, 4, 23, and 28 significantly improved oxidative damage, while compounds 1–5, 7, 11, 13, 18, 19, and 23 significantly improved zebrafish lateral line neuromast inflammation. Additionally, compounds 1, 4, 8, 13, and 16 significantly promoted zebrafish angiogenesis, while compounds 3–5 and 18 significantly improved zebrafish arrhythmia. Furthermore, a flavonoid-targeted metabolomics study revealed that flavanone was the precursor of all of the flavonoids and had its highest accumulation in August, while the others showed their highest accumulation in September. Thus, the best time to harvest most of the bioactive polyphenols is during September. The present study revealed that the wild vegetable S. salsa L. might be developed as a potential cardioprotective functional food.

D/E-rich peptides are less suitable than D/E-deficient peptides for identification by negative-ion HCD due to scarce production of sequencing ions from multiply charged precursors

Highly acidic, D/E-rich peptides or proteins are difficult to identify by positive-ion-mode mass spectrometry (MS), and negative-ion-mode MS is an attractive but insufficiently explored alternative. Based on high-resolution and accurate-mass MS analysis of 115 synthetic peptides of 5–28 amino acids, we confirmed that higher-energy collisional dissociation (HCD) of deprotonated peptides induced abundant backbone or side-chain neutral losses (NL), and updated the ranking list of NLs by abundance. The most abundant fragment ion types are y- > x-, z- > c- if the NL ions are included, or c- > y- > z- > b- if not. The most frequent side-chain NLs involve amino acids C, S, T, D, E, N, Q, and R. Although NL of CO2 is common for all peptides, it is markedly enhanced in D/E-containing peptides. Long peptides and D/E-rich peptides are prone to carrying multiple negative charges. HCD spectra produced from multiply deprotonated peptides have a lower fraction of sequencing ions (i.e., a-, b-, c-, x-, y-, z-ions) than those produced from 1- ([M − H]-) and 2- ([M − 2H]2-) precursors. Based on the above findings, we predict that under negative-ion HCD, D/E-rich peptides should be difficult to identify and that choosing a protease to generate peptides containing fewer D/E residues will improve identification of highly acidic proteins.