MS Mass Research Articles

Influence of comorbidity on infectious complications and antibiotic resistance of pathogens following major liver resections in the setting of biliary obstruction

Objective — to assess the impact of comorbidity on the incidence of postoperative infectious complications after major liver resections in patients with biliary obstruction Materials and methods. The study included 105 patients who were divided into two groups: Group 1 — 53 patients with biliary obstruction (7 with hepatocellular carcinoma (HCC), 28 with cholangiocarcinoma (CC), 18 with colorectal cancer metastases), Group 2 — 52 patients without biliary obstruction (25 with HCC, 10 with CC, and 17 with colorectal cancer metastases). The patients were statistically homogeneous in terms of age and gender. The age of patients in group 1 was on average 60.2±10.7 years, group 2 — 63.5±11.4 years. A microbiological study of 632 isolates of bile (before and after extensive resection), urine, blood, sputum, pharyngeal and wound samples (once) was performed. The bacterial cultures were identified using a Vitek MS mass spectrometry Aanalyser with MALDI‑TOF technology. Results. Patients with primary malignant and metastatic liver tumours and biliary obstruction have the following comorbidity associations: hypertension + heart failure, hypertension + heart failure + diabetes mellitus, hypertension + venous disease of the lower extremities + thrombophlebitis, hypertension + gastroesophageal reflux disease + chronic hepatitis, hypertension + hypothyroidism + metabolic‑associated steatotic liver disease; for patients with primary malignant and metastatic liver tumours without biliary obstruction — arterial hypertension + heart failure, arterial hypertension + heart failure + diabetes mellitus, arterial hypertension + gallstone disease, arterial hypertension + venous disease of the lower extremities + thrombophlebitis, arterial hypertension + bronchial asthma/chronic obstructive pulmonary disease, arterial hypertension + gastroesophageal reflux disease + chronic hepatitis. Conclusions. Biliary obstruction in the setting of comorbidity statistically significantly increases the resistance of Enterococcus faecium strains to cefuroxime, levofloxacin, Staphylococcus aureus — to meropenem, levofloxacin, Klebsiella pneumoniae — to meropenem, cefuroxime, rifaximin, Acinetobacter baumannii — to meropenem, cefuroxime, levofloxacin, rifaximin, Pseudomonas aeruginosa — to cefuroxime, levofloxacin, rifaximin, Enterobacter spp — to meropenem, levofloxacin, rifaximin.

Molecular epidemiology and distribution of Cryptococcus neoformans in human immunodeficiency-positive patients in China.

This study aims to inform the prevention and treatment of Cryptococcus neoformans infections in China by analyzing the molecular epidemiology and distribution patterns of the pathogen. A cross-sectional study was conducted involving a retrospective analysis of 64 clinical strains of Cryptococcus isolated from January 2018 to April 2023 across various domestic regions. Patient information was collected from human immunodeficiency virus-positive individuals in multiple hospitals located in 19 cities within China's southeastern coastal and southwestern regions. A VITEK MS mass spectrometer was employed for strain identification. Variants and mating types were amplified using polymerase chain reaction (PCR), while PCR multilocus sequence typing (MLST) was utilized for molecular genetic analysis of the strains. Evolutionary trees were constructed using MEGA software. The study identified a male predominance (2.37:1) among the 64 strains, with a median patient age of 38.5 years. Most strains (79.69%) were isolated from cerebrospinal fluid. All strains belonged to the Aα, VN I type, with MLST revealing three sequence types: ST5 (89.06%), ST32 (7.81%), and ST186 (3.13%). From 2018 to 2023, Cryptococcus neoformans infections in China were predominantly found in middle-aged men, and the VN I genotype was the most common among the isolated strains.

ИЗУЧЕНИЕ БАКТЕРИАЛЬНЫХ СООБЩЕСТВ ФИЛЛОСФЕРЫ ВИНОГРАДА

As a result, of the conducted research, 20 bacterial strains were isolated from the phyllosphere of grapes selected by the Kuban State Agrarian University, 19 of which were identified by MALDI-TOF MS mass spectrometry as Bacillus sp., 1 as Pantoea agglomerans . As a result, of evaluating their antagonism towards phytopathogens during in vitro joint cultivation, 3 - strains were isolated from disease-resistant grape samples, 2 strains from unstable ones. Each variety had its own specific complex of microscopic bacteria. Keywords: MICROBIOME, PHYLLOSPHERE, GRAPEVINE, BACILLUS SP, MALDI-TOF MS, ANTAGONISM

2-Nitro-4-Carboxyphenylhydrazine and 2,4-Dicarboxylphenylhydrazine as a Pair of Novel Reactive MALDI Matrices for Rapid and Accurate Profiling of N-Glycome in Dual Ion Modes.

N-glycosylation is closely linked to a wide range of biological functions in organisms. Owing to the constriction of awful crystals formed by conventional MALDI matrices and the extremely inferior ionization efficiency of N-glycans, the traditional direct detection of N-glycans by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been gradually replaced by postderivatization detection using reactive matrices. Nevertheless, the laborious identification of complex spectral peaks remains the major difficulty in N-glycan profiling. Hence, we logically designed and synthesized two novel reactive matrices, 2-nitro-4-carboxylphenylhydrazine (NCPH) and 2,4-dicarboxylphenylhydrazine (DCPH), and separately combined them with the acidic matrix 2,5-dihydroxybenzoic acid (DHB) to constitute two composite matrices with high on-target derivatization efficiency and significant promotion of N-glycan ionization for productive MALDI analysis in dual ion modes. Using both composite matrices, we can actualize MALDI-MS and MS2 mass calibration in dual ion modes by postderivatization detection and fragmentation of dextrans and selectively enhance the ionization effect of oligosaccharides in mixed systems. Quite homogeneous cocrystals can ensure N-glycan quantification with decent linearity and reproducibility. A fixed mass difference derived from the identical N-glycan in two ion modes is available for rapid identification in complex biological samples. Ultimately, the developed strategy was triumphantly employed to identify and quantify the relative content and alteration tendency of peach N-glycans, which can be referable to the latent correlation between N-glycan expression and peach ripening.

Spatial metabolomics method to reveal the differences in chemical composition of raw and honey-fried Stemona tuberosa Lour. by using UPLC-Orbitrap Fusion MS and desorption electrospray ionization mass spectrometry imaging.

Stemona tuberosa Lour. (ST) is a significant traditional Chinese medicine (TCM) renowned for its antitussive and insecticidal properties. ST is commonly subjected to processing in clinical practice before being utilized as a medicinal substance. Currently, the customary technique for processing ST is honey-fried. Nevertheless, the specific variations in chemical constituents of ST before and after honey-fried remain unclear. This work aimed to analyze the variations in chemical constituents of ST before and after honey-fried and to study the distribution of differential markers in the roots. UPLC-Orbitrap Fusion MS combined with molecular network analysis was used to analyze the metabolome of ST and honey-fried ST (HST) and to screen the differential metabolites by multivariate statistical analysis. Spatial metabolomics was applied to study the distribution of differential metabolites by desorption electrospray ionization mass spectrometry imaging (DESI-MSI). The ST and HST exhibited notable disparities, with 56 and 61 chemical constituents found from each, respectively. After processing, the types of alkaloids decreased, and 12 differential metabolites were screened from the common compounds. The notable component variations were epibisdehydro-tuberostemonine J, neostenine, tuberostemonine, croomine, neotuberostemonine, and so forth. MSI visualized the spatial distribution of differential metabolites. Our research provided a rapid and effective visualization method for the identification and spatial distribution of metabolites in ST. Compared with the traditional method, this method offered more convincing data supporting the processing mechanism investigations of Stemona tuberosa from a macroscopic perspective.

Analysis of the components of Mycobacterium tuberculosis heat-resistant antigen (Mtb-HAg) and its regulation of γδ T-cell function

BackgroundMycobacterium tuberculosis heat-resistant antigen (Mtb-HAg) is a peptide antigen released from the mycobacterial cytoplasm into the supernatant of Mycobacterium tuberculosis (Mtb) attenuated H37Ra strain after autoclaving at 121 °C for 20 min. Mtb-HAg can specifically induce γδ T-cell proliferation in vitro. However, the exact composition of Mtb-HAg and the protein antigens that are responsible for its function are currently unknown.MethodsMtb-HAg extracted from the Mtb H37Ra strain was subjected to LC‒MS mass spectrometry. Twelve of the identified protein fractions were recombinantly expressed in Escherichia coli by genetic engineering technology using pET-28a as a plasmid and purified by Ni–NTA agarose resin to stimulate peripheral blood mononuclear cells (PBMCs) from different healthy individuals. The proliferation of γδ T cells and major γδ T-cell subset types as well as the production of TNF-α and IFN-γ were determined by flow cytometry. Their proliferating γδ T cells were isolated and purified using MACS separation columns, and Mtb H37Ra-infected THP-1 was co-cultured with isolated and purified γδ T cells to quantify Mycobacterium viability by counting CFUs.ResultsIn this study, Mtb-HAg from the attenuated Mtb H37Ra strain was analysed by LC‒MS mass spectrometry, and a total of 564 proteins were identified. Analysis of the identified protein fractions revealed that the major protein components included heat shock proteins and Mtb-specific antigenic proteins. Recombinant expression of 10 of these proteins in by Escherichia coli genetic engineering technology was used to successfully stimulate PBMCs from different healthy individuals, but 2 of the proteins, EsxJ and EsxA, were not expressed. Flow cytometry results showed that, compared with the IL-2 control, HspX, GroEL1, and GroES specifically induced γδ T-cell expansion, with Vγ2δ2 T cells as the main subset, and the secretion of the antimicrobial cytokines TNF-α and IFN-γ. In contrast, HtpG, DnaK, GroEL2, HbhA, Mpt63, EsxB, and EsxN were unable to promote γδ T-cell proliferation and the secretion of TNF-α and IFN-γ. None of the above recombinant proteins were able to induce the secretion of TNF-α and IFN-γ by αβ T cells. In addition, TNF-α, IFN-γ-producing γδ T cells inhibit the growth of intracellular Mtb.ConclusionActivated γδ T cells induced by Mtb-HAg components HspX, GroES, GroEL1 to produce TNF-α, IFN-γ modulate macrophages to inhibit intracellular Mtb growth. These data lay the foundation for subsequent studies on the mechanism by which Mtb-HAg induces γδ T-cell proliferation in vitro, as well as the development of preventive and therapeutic vaccines and rapid diagnostic reagents.

Yeast Diversity in Honey and Pollen Samples from Stingless Bees in the State of Bahia, Brazil: Use of the MALDI-TOF MS/Genbank Proteomic Technique.

(1) Background: The identification of microorganisms includes traditional biochemical methods, molecular biology methods evaluating the conserved regions of rRNA, and the molecular biology of proteins (proteomics), such as MALDI-TOF MS mass spectrometry. This work aimed to identify the biodiversity of yeasts associated with stingless bee species' honey and pollen, Melipona scutellaris, Nannotrigona testaceicornes, and Tetragonisca angustula, from the region of São Gonçalo dos Campos-Bahia (BA) state, Brazil. (2) Methods: Cellular proteins were extracted from 2837 microbial isolates (pollen and honey) and identified via MALDI-TOF MS. The identified yeast species were also compared to the mass spectra of taxonomically well-characterized reference strains, available from the National Center of Biotechnology Information (NCBI) database. (3) Results: Nine yeast species were identified: Candida maltosa, Candida norvegica, Kazachstania telluris, Schizosaccharomyces pombe, Scheffersomyces insectosus, Meyerozyma guilliermondii, Brettanomyces bruxellensis, Kazachstania exigua, and Starmerella lactis-condensi. Nannotrigona testaceicornes pollen had the highest number of yeast colonies. The yeasts Brettanomyces bruxellensis and Kazachstania telluris showed high populations in the samples of Nannotrigona testaceicornes and Melipona scutellaris, respectively. This work shows that there is some sharing of the same species of yeast between honey and pollen from the same beehive. (4) Conclusions: A total of 71.84% of the identified species present a high level of confidence at the species level. Eight yeast species (Candida maltosa, Candida norvegica, Kazachstania telluris, Schizosaccharomyces pombe, Scheffersomyces insectosus, Meyerozyma guilliermondii, Kazachstania exigua, and Starmerella lactis-condensi) were found for the first time in the samples that the authors inspected. This contributes to the construction of new knowledge about the diversity of yeasts associated with stingless bee products, as well as to the possibility of the biotechnological application of some yeast species.

MALDI-TOF MS/MS Analysis of Permethylated O-Glycan Alditols Released from Mucins.

Mucin glycans are associated with the function of mucin in maintaining mucosal homeostasis. Therefore, the glycomic analysis of mucins is crucial. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is one of the most suitable methods for the glycomic analysis of mucin O-glycans. In this chapter, we describe methods for analyzing permethylated O-glycan alditols released from mucins by MALDI-TOF MS and MALDI-TOF tandem mass spectrometry (MALDI-TOF MS/MS).

The use of a biopeptide with antiviral properties as a functional ingredient for ice cream

Biopeptides are used in food products to give them a functional orientation. The purpose of the study is to characterize and use a biopeptide with antiviral properties for the production of ice cream with functional purpose. The molecular mass distribution of the peptide was evaluated by mass spectrometry and identified by MALDI-TOF and MS mass spectrometry on the MALDI-time-of-flight Ultraflex mass spectrometer (Bruker, Germany). The mass spectra were analyzed using the Mascot program, the Peptide Fingerprint option (Matrix Science, USA) using the Protein NCBI database. The antiviral activity of the peptide was studied on lentiviral particles. The assessment of the physical-chemical parameters of ice cream enriched with a biopeptide was determined according to regulatory documents. As a result of the research, a characteristic of a peptide with antiviral properties is given. It has been established that the peptide consists of 8 amino acids and is classified as an alpha helical cationic antiviral peptide. Ice cream “Vanilla Ice cream 15%” has been developed using synthesized LREGIKNK peptide as a functional ingredient. It is shown that the ice cream meets the requirements of regulatory documentation.

Active peptides with hypoglycemic effect obtained from hemp (Cannabis sativa L) protein through identification, molecular docking, and virtual screening.

Hemp (Cannabis sativa L) seeds are rich in proteins of high nutritional value, which makes the study of beneficial properties of hemp seed proteins and peptides, such as hypotensive and hypoglycemic effects, increasingly attractive. The present results confirm the good processability and stability of the hemp protein hydrolysate obtained by enzymatic hydrolysis of non-dehulled hemp seed meal (NDHM). Six peptides with potential hypoglycemic activity were obtained by ethanol-graded precipitation, Nano LC-Q-Orbitrap-MS/MS mass spectrometry, and computerized virtual screening. Further, validation experiments for in vitro synthesis showed that TGLGR, SPVI, FY, and FR exhibited good α-glucosidase inhibitory activity, respectively. Animal experiments showed that the hemp protein peptides modulated blood glucose and blood lipids in hyperglycemic rats. These results indicate that hemp protein peptides can reduce blood glucose levels in hyperglycemic rats, suggesting that hemp proteins may be a promising natural source for the prevention and treatment of hyperglycemia.

A clinical case of posttraumatic osteomyelitis associated with <i>kytococcus schroeteri</i> and <i>enterococcus faecalis</i>

Introduction. In most cases, osteomyelitis is the monomicrobial disease caused by various Gram-positive bacteria. However, previous injury may contribute to formation of a microbial association. Presence of two or more pathogens in the infectious focus can markedly complicate the disease clinical picture.Kytococcus schroeteriis one of the rarest pathogens found in clinical samples. Slightly more than twenty described cases related to such infection have been recorded globally. The aim of the research was to analyse the first identified clinical case of post-traumatic osteomyelitis associated withKytococcus schroeteriandEnterococcus faecalis.Materials and methods.The bacterial cultures were obtained from the wound discharge of the patient’s shin by the cultural method. Identification of the bacterial cultures was performed using a VITEK MS mass spectrometer followed by 16S rRNA gene sequencing. The morphological, tinctorial and biochemical features of the cultures obtained were established, and their antibacterial resistance was also determined.Results. The clinical case was associated with the diagnosis “Chronic post-traumatic osteomyelitis of the left shin”. Two types of microorganisms were isolated from the wound discharge, and identified asKytococcus schroeteriandEnterococcus faecalisusing the MALDI-ToF mass spectrometry method. 16S rRNA gene sequencing from the isolated bacterial cultures confirmed the MALDI-ToF mass spectrometry data. Antimicrobial susceptibility for this microorganism was determined according to the criteria for the staphylococcal group according to the clinical guide “Determination of sensitivity to antimicrobial drugs (rev. 2021)”.Conclusion. For the first time, the mixed infection caused by two Gram-positive bacteriaK. schroeteriandE. faecalishas been described. Such associations can enhance the pathogenic effects of each other bacterium, which may contribute to transition of the infection to a chronic form with a low probability of positive cultural test.K. schroeteriis a representative of the normal skin microbiota, but this microorganism is able to cause various infections. TheK. schroeterispecies should be differentiated from other representatives of the orderMicrococcales. At cultural examination, resistance to oxacillin is a suspicious sign indicating that the bacterial culture might be potentially assigned toK. schroeterispecies. Due to the unavailability of current biochemical tests for differentiationK. schroeterifrom related taxa, reliable identification of this species is recommended using MALDI-ToF mass spectrometry or 16S rRNA gene sequencing.

Comparison of liquid chromatography-high-resolution tandem mass spectrometry (MS2) and multi-stage mass spectrometry (MS3) for screening toxic natural products

Liquid chromatography-high-resolution mass spectrometry (LC-HR-MS) has emerged as a powerful analytical technology for compound screening in clinical toxicology. To evaluate the potential of LC-HR-MS3 in detecting toxic natural products, a spectral library of 85 natural products (79 alkaloids) that contains both MS2 and MS3 mass spectra was constructed and used to identify the natural products. Samples were analyzed using an LC-HR-MS3 method and the generated data were matched to the spectral library to identify the natural products. To test the performance of the LC-HR-MS3 method in different sample matrices, the 85 natural product standards were divided into three groups to separate structural isomers and avoid ion suppression effects caused by co-elution of multiple analytes. The grouped analytes were spiked into drug-free serum and drug-free urine to produce contrived clinical samples. The compound identification results of the 85 natural products in urine and serum samples were obtained. The match scores using both MS2 and MS3 mass spectra and those using only MS2 mass spectra were compared at 10 different analyte concentrations. The two types of data analysis provided identical identification results for the majority of the analytes (96% in serum, 92% in urine), whereas, for the remaining analytes, the MS2-MS3 tree data analysis had better performance in identifying them at lower concentrations. This study shows that in comparison to LC-HR-MS (MS2), LC-HR-MS3 can increase the performance in identification of a small group of the toxic natural products tested in serum and urine specimens.

Isolation of a rare pathogen <i>Chryseobacterium indologenes</i> in patients with pneumonia

Introduction. Chryseobacterium indologenes bacteria are rarely detected, poorly studied opportunistic bacteria of the nonfermenting gram-negative bacilli group that are characterized by high intrinsic and acquired multidrug resistance and involvement in healthcare associated infections.Aim. To analyze detection rate of C. indologenes strains from various biomaterials obtained from patients with pneumonia, as well as levels of pathogen drug resistance to antimicrobial drugs.Materials and methods. The research included 1740 clinical samples obtained from patients with pneumonia hospitalized in in-patient facilities of the Khabarovsk city during the COVID-19 pandemic. Clinical samples included 1305 respiratory samples (744 sputum samples and 561 nasopharyngeal swabs), 435 samples of autopsy material (lung tissue) obtained from patients with a fatal outcome of the disease. The study was performed via classical bacteriological method. Pathogens were identified with Vitek 2 bacteriological analyzer and Vitek MS mass spectrometer. Sensitivity to antimicrobial drugs was determined by disk-diffusion method and in a bacteriological analyzer.Results. A comparative analysis of detection of the entire nonfermenting gram-negative bacteria (NFGNB) group and C. indologenes from various clinical samples was carried out. Detection rate of NFGNB equaled 17.3%. NFGNB were isolated from autopsy material most often ‒ in 31.7% of cases, less often ‒ from sputum and nasopharyngeal smears (13.8% and 10.7%, respectively). C. indologenes was detected in 0.5% of the cases (8 isolates out of 1740 samples). Isolation of this pathogen was most frequent in nasopharyngeal smears – in 1.1% (6 cases out of 561 samples), least frequent ‒ from sputum, which totaled 0.3% (2 isolates from 744 samples). The detection rate of the pathogen in respiratory samples equaled 0.6% (8 isolates out of 1305 samples). This pathogen was not found in the autopsy material. Carbapenem-resistant variants of C. indologenes were isolated in 75% (6 cases out of 8) of the cases.Conclusion. Further intensifying of diagnostic methods will result in more frequent detection of these unusual pathogens, clinical significance of which needs more justification.

Can lithium contents in mica be correctly calculated? Tischendorf́s proposal (Mineralogical Magazine 61/1997) 25 years after

AbstractMicas are the most common hosts of lithium in granitoid igneous rocks. Unfortunately, their Li contents cannot be determined by electron-probe microanalysis (EPMA) which is the most common method of mineral analysis. In an effort to avoid the use of other, technically more complex and expensive methods, several empirical schemes for the estimation of Li-contents from EPMA data have been developed. The methods proposed by Tischendorf (Mineralogical Magazine, 1997) have found the widest application. After 25 years of common usage, we have evaluated these methods by direct Li determination using laser ablation-inductively coupled plasma-mass spectrometry (LA–ICP–MS). Approximately 3000 spot analyses of Li in micas from eight areas worldwide obtained by LA–ICP–MS were compared with the values yielded by the methods of Tischendorf. We conclude that none of the lithium estimation methods can compensate fully for a real local analysis by LA–ICP–MS or secondary-ion mass spectrometry (SIMS). Generally, SiO2-based estimation for trioctahedral micas provides a better match to the analysed values than F-based estimation for dioctahedral micas. The Rb-based estimation for dioctahedral micas does not provide acceptable results. The usage of averaged Si- and F-based estimations can be accepted in common petrological studies for a general characterisation of mica species. Large errors of individual spot estimations preclude their usage in detailed mineralogical studies.

Dynamical formation of Gaia BH1 in a young star cluster

ABSTRACT Gaia BH1, the first quiescent black hole (BH) detected from Gaia data, poses a challenge to most binary evolution models: its current mass ratio is ≈0.1, and its orbital period seems to be too long for a post-common envelope system and too short for a non-interacting binary system. Here, we explore the hypothesis that Gaia BH1 formed through dynamical interactions in a young star cluster (YSC). We study the properties of BH-main sequence (MS) binaries formed in YSCs with initial mass 3 × 102–3 × 104 M⊙ at solar metallicity, by means of 3.5 × 104 direct N-body simulations coupled with binary population synthesis. For comparison, we also run a sample of isolated binary stars with the same binary population synthesis code and initial conditions used in the dynamical models. We find that BH-MS systems that form via dynamical exchanges populate the region corresponding to the main orbital properties of Gaia BH1 (period, eccentricity, and masses). In contrast, none of our isolated binary systems match the orbital period and MS mass of Gaia BH1. Our best-matching Gaia BH1-like system forms via repeated dynamical exchanges and collisions involving the BH progenitor star, before it undergoes core collapse. YSCs are at least two orders of magnitude more efficient in forming Gaia BH1-like systems than isolated binary evolution.

Rapid Identification of Alkaloids and Flavonoids in Fissistigma oldhamii var. longistipitatum by Ultra High-Performance Liquid Chromatography and Quadrupole Time-of-Flight Tandem Mass Spectrometry.

The herb Fissistigma oldhamii var. longistipitatum has been used for a long time in Asian folk medicine in the treatment of several diseases, including rheumatoid arthritis and other inflammatory conditions. Researchers in China and elsewhere have analyzed and characterized its chemical content. In this study, a UHPLC-Q-TOF-MS/MS method, run in both positive and negative modes, was used to identify the main chemical compounds in dichloromethane extracts of this F. oldhamii variant. A total of 64 compounds, including 44 alkaloids and 20 flavonoids, were rapidly identified or tentatively characterized by comparing the molecular ion peaks and MS2 mass spectrometry fragment ions, combined with the mass spectrometry information of reference substances, appropriate fragmentation ions and related literatures. For the first time, the developed UHPLC-Q-TOF-MS/MS analysis method allows for the determination of 64 compounds from extracts of the F. oldhamii variant. The method presented here produced results that will be useful in further studies of this herb.

Feasibility study on the homogeneity and stability of megastigmatrienone isomers for the development of certified reference material

Feasibility study on the homogeneity and stability of megastigmatrienone isomers for the development of certified reference material

Detection of trace chlorine pollutants in recycled pulp using gas chromatography-tandem mass spectrometry with response surface-optimized carbon structure online catalysis.

Chlorinated aromatics and alkanes are widely used for their flame retardancy, but they need to be monitored when used in recycled pulp. This paper reports the use of palladium acetate/activated carbon (Pa/Ac) activated by nitric acid as an online catalyst to determine chlorinated aromatics and chlorinated alkanes in recycled paper products using gas chromatography-tandem mass spectrometry (GC-MS/MS), which significantly improves the sensitivity of the method and remarkably lowers the detection limits. The Pa/Ac catalyst was prepared using a self-made catalytic device and used as key to the online catalytic conversion of target chlorinated aromatic hydrocarbons and chlorinated alkanes for GC-MS/MS analysis. The response surface model was used to optimize catalytic conditions. Then GC-MS/MS in the multireaction monitoring mode with online catalysis was applied for the analysis of polychlorinated biphenyls, polychlorinated terphenyls, polychlorinated naphthalene, and chlorinated paraffins (CP) in recycled paper products. Compared with traditional methods, the Pa/Ac catalyst can transform chlorinated aromatic hydrocarbons into aromatic hydrocarbons through dechlorination hydrogenation, thus lowering the detection limit of the GC-MS/MS method significantly. It can transform paraffin chloride into the corresponding alkane to better distinguish short-chain, medium-chain, or long-chain CPs. Online catalytic conversion significantly improved the sensitivity and reproducibility (88.7%-113.1%) of the method. Tissue samples with various concentration levels of chlorinated aromatics and chlorinated alkanes were tested. The linearity range of the reduced target compounds in the reduction product solution was 0.02-1.00 μg/ml (R2 >0.995). The quantitative detection limit was 0.03-0.05 μg/kg, and relative standard deviation was less than 6.9%. This study was the first to introduce the Pa/Ac catalytic device as an online catalytic unit in the determination of chlorinated aromatics and chlorinated alkanes using the GC-MS/MS method. The target compounds were converted into alkanes and aromatic hydrocarbons with unchanged carbon structures, and the method could achieve a low detection limit with no need for high-end methods such as GC-chemical ionization ion source (CI)-MS or high-resolution mass spectrometry. These methods are suitable for the determination of chlorine pollutants in recycled paper and its raw materials.

A MATLAB-based app to improve LC–MS/MS data analysis for N-linked glycan peak identification

BackgroundGlycosylation is an important modification to proteins that plays a significant role in biological processes. Glycan structures are characterized by liquid chromatography (LC) combined with mass spectrometry (MS), but data interpretation of LC/MS and MS/MS data can be time-consuming and arduous when analyzed manually. Most of glycan analysis requires dedicated glycobioinformatics tools to process MS data, identify glycan structure, and display the results. However, software tools currently available are either too costly or heavily focused on academic applications, limiting their use within the biopharmaceutical industry for implementing the standardized LC/MS glycan analysis in high-throughput manner. Additionally, few tools provide the capability to generate report-ready annotated MS/MS glycan spectra.ResultsHere, we present a MATLAB-based app, GlyKAn AZ, which can automate data processing, glycan identification, and customizable result displays in a streamlined workflow. MS1 and MS2 mass search algorithms along with glycan databases were developed to confirm the fluorescent labeled N-linked glycan species based on accurate mass. A user-friendly graphical user interface (GUI) streamlines the data analysis process, making it easy to implement the software tool in biopharmaceutical analytical laboratories. The databases provided with the app can be expanded through the Fragment Generator functionality which automatically identifies fragmentation patterns for new glycans. The GlyKAn AZ app can automatically annotate the MS/MS spectra, yet this data display feature remains flexible and customizable by users, saving analysts’ time in generating individual report-ready spectra figures. This app accepts both OrbiTrap and matrix-assisted laser desorption/ionization–time of flight (MALDI–TOF) MS data and was successfully validated by identifying all glycan species that were previously identified manually.ConclusionsThe GlyKAn AZ app was developed to expedite glycan analysis while maintaining a high level of accuracy in positive identifications. The app’s customizable user inputs, polished figures and tables, and unique calculated outputs set it apart from similar software and greatly improve the current manual analysis workflow. Overall, this app serves as a tool for streamlining glycan identification for both academic and industrial needs.

The Potassium Channel Blocker β-Bungarotoxin from the Krait Bungarus multicinctus Venom Manifests Antiprotozoal Activity

Protozoal infections are a world-wide problem. The toxicity and somewhat low effectiveness of the existing drugs require the search for new ways of protozoa suppression. Snake venom contains structurally diverse components manifesting antiprotozoal activity; for example, those in cobra venom are cytotoxins. In this work, we aimed to characterize a novel antiprotozoal component(s) in the Bungarus multicinctus krait venom using the ciliate Tetrahymena pyriformis as a model organism. To determine the toxicity of the substances under study, surviving ciliates were registered automatically by an original BioLaT-3.2 instrument. The krait venom was separated by three-step liquid chromatography and the toxicity of the obtained fractions against T. pyriformis was analyzed. As a result, 21 kDa protein toxic to Tetrahymena was isolated and its amino acid sequence was determined by MALDI TOF MS and high-resolution mass spectrometry. It was found that antiprotozoal activity was manifested by β-bungarotoxin (β-Bgt) differing from the known toxins by two amino acid residues. Inactivation of β-Bgt phospholipolytic activity with p-bromophenacyl bromide did not change its antiprotozoal activity. Thus, this is the first demonstration of the antiprotozoal activity of β-Bgt, which is shown to be independent of its phospholipolytic activity.