Impact of Ultrafiltration on the Physicochemical Properties of Bovine Lactoferrin: Insights into Molecular Mass, Surface Morphology, and Elemental Composition.

The large-scale isolation of bovine lactoferrin (bLF) typically involves using large amounts of concentrated eluents, which might introduce impurities to the final product. Sometimes, protein pre-concentration is required for the greater accuracy of experimental results. In this research, the supplied bLF sample was subjected to additional ultrafiltration (UF) to eliminate possible small impurities, such as salts and peptides of bLF. Beforehand, the basic characterization of native bLF, including surface-charge properties and the structural sensitivity to the various pH conditions, was performed. The study aimed to evaluate the difference in molecular mass, primary structure, surface morphology, and elemental composition of the protein before and after UF. The research was provided by application of spectroscopic, spectrometric, electrophoretic, and microscopic techniques. The evident changes in the surface morphology of bLF were observed after UF, while the molecular masses of both proteins were comparable. According to MALDI-TOF/MS results, UF had a positive impact on the bLF sample representation, improving the identification parameters, such as sequence coverage and intensity coverage.

Advances in LDI-MS Analysis: The Role of Chemical Vapor Deposition-Synthesized Silver Nanoparticles in Enhancing Detection of Low-Molecular-Weight Biomolecules.

In this investigation, we detail the synthesis of silver nanoparticles (AgNPs) via a precise chemical vacuum deposition (CVD) methodology, aimed at augmenting the analytical performance of laser desorption/ionization mass spectrometry (LDI-MS) for the detection of low-molecular-weight analytes. Employing a precursor supply rate of 0.0014 mg/s facilitated the formation of uniformly dispersed AgNPs, characterized by SEM and AFM to have an average diameter of 33.5 ± 1.5 nm and a surface roughness (Ra) of 11.8 nm, indicative of their homogeneous coverage and spherical morphology. XPS and SEM-EDX analyses confirmed the metallic silver composition of the nanoparticles with Ag peak splitting, reflecting the successful synthesis of metallic Ag. Comparative analytical evaluation with traditional MALDI matrices revealed that AgNPs significantly reduce signal suppression, thereby enhancing the sensitivity and specificity of LDI-MS for low-molecular-weight compounds such as triglycerides, saccharides, amino acids, and carboxylic acids. Notably, the application of AgNPs demonstrated a superior linear response for triglyceride signals with regression coefficients surpassing 0.99, markedly outperforming conventional matrices. The study further extends into quantitative analysis through nanoparticle-based laser desorption/ionization (NALDI), where AgNPs exhibited enhanced ionization efficiency, characterized by substantially lower limits of detection (LOD) and quantification (LOQ) for tested standards. Particular attention was paid to lipids with a detailed examination of their fragmentation pathways. These results highlight the significant potential of AgNPs synthesized via CVD to transform the analytical detection and quantification of low-molecular-weight compounds using NALDI. This approach offers a promising avenue for expanding the scope of analytical applications in mass spectrometry and introducing innovative methodologies for enhanced precision and sensitivity.

Antifungal Properties of Bio-AgNPs against D. pinodes and F. avenaceum Infection of Pea (Pisum sativum L.) Seedlings.

Ascochyta blight and Fusarium root rot are the most serious fungal diseases of pea, caused by D. pinodes and F. avenaceum, respectively. Due to the lack of fully resistant cultivars, we proposed the use of biologically synthesized silver nanoparticles (bio-AgNPs) as a novel protecting agent. In this study, we evaluated the antifungal properties and effectiveness of bio-AgNPs, in in vitro (poisoned food technique; resazurin assay) and in vivo (seedlings infection) experiments, against D. pinodes and F. avenaceum. Moreover, the effects of diseases on changes in the seedlings' metabolic profiles were analyzed. The MIC for spores of both fungi was 125 mg/L, and bio-AgNPs at 200 mg/L most effectively inhibited the mycelium growth of D. pinodes and F. avenaceum (by 45 and 26%, respectively, measured on the 14th day of incubation). The treatment of seedlings with bio-AgNPs or fungicides before inoculation prevented the development of infection. Bio-AgNPs at concentrations of 200 mg/L for D. pinodes and 100 mg/L for F. avenaceum effectively inhibited infections' spread. The comparison of changes in polar metabolites' profiles revealed disturbances in carbon and nitrogen metabolism in pea seedlings by both pathogenic fungi. The involvement of bio-AgNPs in the mobilization of plant metabolism in response to fungal infection is also discussed.

Silicon's Influence on Polyphenol and Flavonoid Profiles in Pea (Pisum sativum L.) under Cadmium Exposure in Hydroponics: A Study of Metabolomics, Extraction Efficacy, and Antimicrobial Properties of Extracts.

The current study aimed to investigate the impact of silicon (Si) supplementation in the form of Na2SiO3 on the metabolome of peas under normal conditions and following exposure to cadmium (Cd) stress. Si is known for its ability to enhance stress tolerance in various plant species, including the mitigation of heavy metal toxicity. Cd, a significant contaminant, poses risks to both human health and the environment. The study focused on analyzing the levels of bioactive compounds in different plant parts, including the shoot, root, and pod, to understand the influence of Si supplementation on their biosynthesis. Metabolomic analysis of pea samples was conducted using a targeted HPLC/MS approach, enabling the identification of 15 metabolites comprising 9 flavonoids and 6 phenolic acids. Among the detected compounds, flavonoids, such as flavon and quercetin, along with phenolic acids, including chlorogenic acid and salicylic acid, were found in significant quantities. The study compared Si supplementation at concentrations of 1 and 2 mM, as well as Cd stress conditions, to evaluate their effects on the metabolomic profile. Additionally, the study explored the extraction efficiency of three different methods: accelerated solvent extraction (ASE), supercritical fluid extraction (SFE), and maceration (MAC). The results revealed that SFE was the most efficient method for extracting polyphenolic compounds from the pea samples. Moreover, the study investigated the stability of polyphenolic compounds under different pH conditions, ranging from 4.0 to 6.0, providing insights into the influence of the pH on the extraction and stability of bioactive compounds.

The usefulness of the MALDI-TOF MS technique in the determination of dairy samples' microbial composition: comparison of the new EXS 2600 system with MALDI Biotyper platform.

This study compared the EXS 2600 system with the MALDI Biotyper for identifying microorganisms in dairy samples. Of the 196 bacterial isolates from milk, whey, buttermilk, cream, and dairy wastewater, the species and genus consistent identification between two systems showed 74% and 99%, respectively. However, the level of species identification rate exhibited a difference, which was higher in Zybio than in Bruker-76.0% and 66.8%, respectively. Notably, the EXS 2600 system performed better with certain yeast species and H. alvei, while the Biotyper excelled with Pseudomonas bacteria. Unique microbial compositions were found in 85% of dairy samples, with whey and buttermilk having the highest diversity. This research highlights the EXS 2600's potential as a reliable dairy microbial identification tool and underscores the need for a more diverse and comprehensive spectral database, despite the database's focus on clinical applications (as announced).

Metabolic profiling of bacteria with the application of polypyrrole-MOF SPME fibers and plasmonic nanostructured LDI-MS substrates.

Here we present application of innovative lab-made analytical devices such as plasmonic silver nanostructured substrates and polypyrrole-MOF solid-phase microextraction fibers for metabolic profiling of bacteria. For the first time, comprehensive metabolic profiling of both volatile and non-volatile low-molecular weight compounds in eight bacterial strains was carried out with utilization of lab-made devices. Profiles of low molecular weight metabolites were analyzed for similarities and differences using principal component analysis, hierarchical cluster analysis and random forest algorithm. The results showed clear differentiation between Gram positive (G+) and Gram negative (G-) species which were identified as distinct clusters according to their volatile metabolites. In case of non-volatile metabolites, differentiation between G+ and G- species and clustering for all eight species were observed for the chloroform fraction of the Bligh & Dyer extract, while methanolic fraction failed to recover specific ions in the profile. Furthermore, the results showed correlation between volatile and non-volatile metabolites, which suggests that lab-made devices presented in the current study might be complementary and therefore, useful for species differentiation and gaining insights into bacterial metabolic pathways.

Comparison of the Bruker Microflex LT and Zybio EXS2600 MALDI TOF MS systems for the identification of clinical microorganisms.

The emergence of Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry (MALDI TOF MS) technology has expanded the capabilities for identifying microorganisms in clinical labs, replacing traditional biochemical testing with a proteomic approach. In the present study, we compared results between the two commercial MALDI TOF MS systems, Bruker Microflex LT Biotyper and Zybio EXS2600 Ex-Accuspec, for the identification of 1979 urinary isolates by direct extraction method. Current study found that both systems identified a high percentage of isolates to at least the genus level - Bruker 95.6 % of isolates, Zybio 92.4 %. In the case of 89.5 % of all analyzed spectra, the identification results were consistent between the used devices. The highest score values and the highest percentage of spectra identified to species were obtained for gram-negative bacteria. The results show that both systems are equally good choices in terms of analytical performance for routine microbiological diagnostic procedures.

Study of sample preparation influence on bacterial lipids profile in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Lipids are one of the cell components therefore it is important to be able to accurately assess them. One of the analytical techniques used to study lipid profiles is matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS). The present study attempted to select optimal conditions for sample preparation and MALDI MS analysis of bacterial lipidome in both positive and negative ion modes using different extraction protocols-Folch, Matyash, and Bligh & Dyer, solvents used to apply samples, and matrices such as 9-aminoacridine (9-AA), α-cyano-4-hydroxycinnamic acid (CHCA), 2,5-dihydroxybenzoic acid (DHB), 2-mercaptobenzothiazole (MBT), and 2,4,6-trihydroxyacetophenone (THAP). The obtained results allowed concluding that DHB or CHCA matrices are suitable for lipid analysis in the positive mode, and in the negative mode THAP or 9-AA. The most appropriate protocol for extracting lipids from bacterial cells was the Bligh & Dyer method in both ionization modes. The use of the solvent TA30, which was a mixture of acetonitrile and 0.1% trifluoroacetic acid in water, provided on the spectra a significant number of signals from lipids in all groups analyzed, such as fatty acyls, glycerolipids, and glycerophospholipids.

Silver Lactoferrin as Antimicrobials: Mechanisms of Action and Resistance Assessed by Bacterial Molecular Profiles.

A diverse silver-lactoferrin (AgLTF) complex, comprising silver ions (Ag+) and silver nanoparticles, displayed a synergistic antibacterial effect while being almost five times more lethal than LTF alone. Gas chromatography-mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry-in linear (LP) and reflectron (RP) positive modes-were used to comprehensively analyze metabolites and proteins profiles of bacteria (Staphylococcus aureus (SA), Pseudomonas aeruginosa (PA) and Enterococcus faecalis (EF)) treated using AgLTF complex versus exclusively Ag+. Although both agents resulted in similar metabolic shifts in bacteria, AgLTF significantly triggered the production of sulfides (related to bacterial stress resistance), ethanol, 2-butanol (indicating exhaustion of cell respiration), decanoic acid, and nonane (suggesting ongoing oxidative stress). Keto acids formation and fermentation pathways were enhanced by AgLTF and suppressed by Ag+. Furthermore, AgLTF appears to interact with proteins fraction of bacteria in a concentration-dependent manner. EF molecular profiles showed less changes between treated and untreated bacteria. On the other hand, SA and PA proteins and metabolic patterns were the most differentiated from untreated bacteria. In conclusion, our study may provide valuable insights regarding the molecular mechanisms involved in AgLTF antimicrobial action.

The Multifaceted Roles of Bovine Lactoferrin: Molecular Structure, Isolation Methods, Analytical Characteristics, and Biological Properties.

Bovine lactoferrin (bLF) is widely known as an iron-binding glycoprotein from the transferrin family. The bLF molecule exhibits a broad spectrum of biological activity, including iron delivery, antimicrobial, antiviral, immunomodulatory, antioxidant, antitumor, and prebiotic functions, thereby making it one of the most valuable representatives for biomedical applications. Remarkably, LF functionality might completely differ in dependence on the iron saturation state and glycosylation patterns. Recently, a violently growing demand for bLF production has been observed, mostly for infant formulas, dietary supplements, and functional food formulations. Unfortunately, one of the reasons that inhibit the development of the bLF market and widespread protein implementation is related to its negligible amount in both major sources─colostrum and mature milk. This study provides a comprehensive overview of the significance of bLF research by delineating the key structural characteristics of the protein and elucidating their impact on its physicochemical and biological properties. Progress in the development of optimal isolation techniques for bLF is critically assessed, alongside the challenges that arise during its production. Furthermore, this paper presents a curated list of the most relevant instrumental techniques for the characterization of bLF. Lastly, it discusses the prospective applications and future directions for bLF-based formulations, highlighting their potential in various fields.

Implications of Sample Preparation Methods on the MALDI-TOF MS Identification of Spore-Forming Bacillus Species from Food Samples: A Closer Look at Bacillus licheniformis, Peribacillus simplex, Lysinibacillus fusiformis, Bacillus flexus, and Bacillus marisflavi.

This research underscores the criticality of tailored culture conditions and incubation periods for effective and accurate identification of spore-forming bacteria: Bacillus licheniformis, Peribacillus simplex, Lysinibacillus fusiformis, Bacillus flexus, and Bacillus marisflav, isolated from food samples, utilizing the MALDI-TOF MS technique. All isolated strains were confirmed as Gram-positive bacteria from diverse genera through 16S rDNA gene sequencing. To enhance the accuracy of the identification process, the study employed an optimization strategy involving a varied incubation time (ranging from 1 to 48 h) and two distinct sample preparation approaches-direct transfer facilitated by formic acid and protein extraction via ethanol. It was observed that matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) could successfully identify approximately 47% of the samples following a 24 h incubation period. The study emphasizes the critical role of sample preparation methods in enabling precise bacterial identification. Our findings reveal the necessity of tailoring the incubation time for each sample, as the optimum period for accurate identification fluctuated between 1 and 12 h. Further demonstrating the interplay between incubation time and spore quantity, our study used the Schaeffer-Fulton staining method to show that the lowest spore counts were detected between 5 and 8 h of incubation. This provides evidence that spore formation impacts bacterial identification. Our research thus deepens the understanding of spore-forming bacteria identification using MALDI-TOF MS and illuminates the various factors affecting the dependability and accuracy of this technique. Future research may explore additional variables, such as the effect of varying culture media, to further augment identification accuracy and gain a holistic understanding of spore-forming bacterial behavior in food samples. By enhancing our knowledge, these findings can substantially contribute to improving food safety and quality assurance strategies by enabling the more accurate and efficient identification of spore-forming bacteria in the food industry, thereby elevating the standards of food safety.

Immobilized enzyme microreactors for analysis of tryptic peptides in ß-casein and ß-lactoglobulin.

In this study, our primary objective was to develop an effective analytical method for studying trypsin-digested peptides of two proteins commonly found in cow's milk: ß-casein (ßCN) and ß-lactoglobulin (ßLG). To achieve this, we employed two distinct approaches: traditional in-gel protein digestion and protein digestion using immobilized enzyme microreactors (µ-IMER). Both methods utilized ZipTip pipette tips filled with C18 reverse phase media for sample concentration. The µ-IMER was fabricated through a multi-step process that included preconditioning the capillary, modifying its surface, synthesizing a monolithic support, and further surface modification. Its performance was evaluated under HPLC chromatography conditions using a small-molecule trypsin substrate (BAEE). Hydrolysates from both digestion methods were analyzed using MALDI-TOF MS. Our findings indicate that the µ-IMER method demonstrated superior sequence coverage for oxidized molecules in ßCN (33 ± 1.5%) and ßLG (65 ± 3%) compared to classical in-gel digestion (20 ± 2% for ßCN; 49 ± 2% for ßLG). The use of ZipTips further improved sequence coverage in both classical in-gel digestion (26 ± 1% for ßCN; 60 ± 4% for ßLG) and µ-IMER (41 ± 3% for ßCN; 80 ± 5% for ßLG). Additionally, phosphorylations were identified. For ßCN, no phosphorylation was detected using classical digestion, but the use of ZipTips showed a value of 27 ± 4%. With µ-IMER and µ-IMER-ZipTip, the values increased to 30 ± 2% and 33 ± 1%, respectively. For ßLG, the use of ZipTip enabled the detection of a higher percentage of modified peptides in both classical (79 ± 2%) and µ-IMER (79 ± 4%) digestions. By providing a comprehensive comparison of traditional in-gel digestion and µ-IMER methods, this study offers valuable insights into the advantages and limitations of each approach, particularly in the context of complex biological samples. The findings set a new benchmark in protein digestion and analysis, highlighting the potential of µ-IMER systems for enhanced sequence coverage and post-translational modification detection.

Metal tolerance and Cd phytoremoval ability in Pisum sativum grown in spiked nutrient solution.

In the presented study, the effects of cadmium (Cd) stress and silicon (Si) supplementation on the pea plant (Pisum sativum L.) were investigated. The tendency to accumulate cadmium in the relevant morphological parts of the plant (roots and shoots respectively)-bioaccumulation, the transfer of this element in the plant (translocation) and the physiological parameters of the plant through indicators of oxidative stress were determined. Model studies were carried out at pH values 6.0 and 5.0 plant growth conditions in the hydroponic cultivation. It was shown that Cd accumulates mostly in plant roots at both pH levels. However, the Cd content is higher in the plants grown at lower pH. The Cd translocation factor was below 1.0, which indicates that the pea is an excluder plant. The contamination of the plant growth environment with Cd causes the increased antioxidant stress by the growing parameters of the total phenolic content (TPC), polyphenol oxidase activity (PPO), the malondialdehyde (MDA) and lipid peroxidation (LP). The results obtained showed that the supplementation with Si reduces these parameters, thus lowering the oxidative stress of the plant. Moreover, supplementation with Si leads to a lower content of Cd in the roots and reduces bioaccumulation of Cd in shoots and roots of pea plants.

Multi-Instrumental Analysis Toward Exploring the Diabetic Foot Infection Microbiota.

The polymicrobial nature of diabetic foot infection (DFI) makes accurate identification of the DFI microbiota, including rapid detection of drug resistance, challenging. Therefore, the main objective of this study was to apply matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI TOF MS) technique accompanied by multiply culture conditions to determine the microbial patterns of DFIs, as well as to assess the occurrence of drug resistance among Gram-negative bacterial isolates considered a significant cause of the multidrug resistance spread. Furthermore, the results were compared with those obtained using molecular techniques (16S rDNA sequencing, multiplex PCR targeting drug resistance genes) and conventional antibiotic resistance detection methods (Etest strips). The applied MALDI-based method revealed that, by far, most of the infections were polymicrobial (97%) and involved many Gram-positive and -negative bacterial species-19 genera and 16 families in total, mostly Enterobacteriaceae (24.3%), Staphylococcaceae (20.7%), and Enterococcaceae (19.8%). MALDI drug-resistance assay was characterized by higher rate of extended-spectrum beta-lactamases (ESBLs) and carbapenemases producers compared to the reference methods (respectively 31% and 10% compared to 21% and 2%) and revealed that both the incidence of drug resistance and the species composition of DFI were dependent on the antibiotic therapy used. MALDI approach included antibiotic resistance assay and multiply culture conditions provides microbial identification at the level of DNA sequencing, allow isolation of both common (eg. Enterococcus faecalis) and rare (such as Myroides odoratimimus) bacterial species, and is effective in detecting antibiotic-resistance, especially those of particular interest-ESBLs and carbapenemases.

A novel effective bio-originated methylene blue adsorbent: the porous biosilica from three marine diatom strains of Nanofrustulum spp. (Bacillariophyta).

In the present paper, for the first time the ability of the porous biosilica originated from three marine diatom strains of 'Nanofrustulum spp.' viz. N. wachnickianum (SZCZCH193), N. shiloi (SZCZM1342), N. cf. shiloi (SZCZP1809), to eliminate MB from aqueous solutions was investigated. The highest biomass was achieved under silicate enrichment for N. wachnickianum and N. shiloi (0.98 g L-1 DW and 0.93 g L-1 DW respectively), and under 15 °C for N. cf. shiloi (2.2 g L-1 DW). The siliceous skeletons of the strains were purified with hydrogen peroxide and characterized by SEM, EDS, the N2 adsorption/desorption, XRD, TGA, and ATR-FTIR. The porous biosilica (20 mg DW) obtained from the strains i.e. SZCZCH193, SZCZM1342, SZCZP1809, showed efficiency in 77.6%, 96.8%, and 98.1% of 14 mg L-1 MB removal under pH 7 for 180 min, and the maximum adsorption capacity was calculated as 8.39, 19.02, and 15.17 mg g-1, respectively. Additionally, it was possible to increase the MB removal efficiency in alkaline (pH = 11) conditions up to 99.08% for SZCZP1809 after 120 min. Modelling revealed that the adsorption of MB follows Pseudo-first order, Bangham's pore diffusion and Sips isotherm models.

Comprehensive Study of Si-Based Compounds in Selected Plants (Pisum sativum L., Medicago sativa L., Triticum aestivum L.).

This review describes the role of silicon (Si) in plants. Methods of silicon determination and speciation are also reported. The mechanisms of Si uptake by plants, silicon fractions in the soil, and the participation of flora and fauna in the Si cycle in terrestrial ecosystems have been overviewed. Plants of Fabaceae (especially Pisum sativum L. and Medicago sativa L.) and Poaceae (particularly Triticum aestivum L.) families with different Si accumulation capabilities were taken into consideration to describe the role of Si in the alleviation of the negative effects of biotic and abiotic stresses. The article focuses on sample preparation, which includes extraction methods and analytical techniques. The methods of isolation and the characterization of the Si-based biologically active compounds from plants have been overviewed. The antimicrobial properties and cytotoxic effects of known bioactive compounds obtained from pea, alfalfa, and wheat were also described.

Electropolymerized polypyrrole-MOF composite as a coating material for SPME fiber for extraction VOCs liberated by bacteria.

The synthesis of efficient and low-cost coatings for solid-phase microextraction attracted much attention. Conductive polymers are excellent candidates for this purpose due to the possibility of electropolymerization, which results in the reproducible synthesis of films. A plethora of studies reported in the literature concluded that modification of conductive polymers with innovative materials could lead to an increase in sensitivity toward specific analytes. In this work, the metal-organic framework-polypyrrole composite was electrodeposited in one step directly onto a stainless-steel substrate. The effect of synthesis parameters on extraction efficiency was investigated. The obtained PPy@ZIF-8 coating was subjected to physical-chemical characterization using electron microscopy and Fourier-transform IR spectroscopy. The main finding of the study was that the values of the limit of detection and intra- and inter-day reproducibility for analytes with different chemical structures were found to be lower as compared to pure polypyrrole coating. Furthermore, the obtained polypyrrole-MOF coating was applied for the collection of profiles of volatile organic compounds liberated by bacteria. Hence, the polypyrrole@ZIF-8 coating synthesized using a low-cost and facile approach presented in this study can be useful for the profiling of VOCs liberated by bacteria.

Removal of the Basic and Diazo Dyes from Aqueous Solution by the Frustules of Halamphora cf. salinicola (Bacillariophyta).

Industrial wastes with hazardous dyes serve as a major source of water pollution, which is considered to have an enormous impact on public health. In this study, an eco-friendly adsorbent, the porous siliceous frustules extracted from the diatom species Halamphora cf. salinicola, grown under laboratory conditions, has been identified. The porous architecture and negative surface charge under a pH of 7, provided by the various functional groups via Si-O, N-H, and O-H on these surfaces, revealed by SEM, the N2 adsorption/desorption isotherm, Zeta-potential measurement, and ATR-FTIR, respectively, made the frustules an efficient mean of removal of the diazo and basic dyes from the aqueous solutions, 74.9%, 94.02%, and 99.81% against Congo Red (CR), Crystal Violet (CV), and Malachite Green (MG), respectively. The maximum adsorption capacities were calculated from isotherms, as follows: 13.04 mg g-1, 41.97 mg g-1, and 33.19 mg g-1 against CR, CV, and MG, respectively. Kinetic and isotherm models showed a higher correlation to Pore diffusion and Sips models for CR, and Pseudo-Second Order and Freundlich models for CV and MG. Therefore, the cleaned frustules of the thermal spring-originated diatom strain Halamphora cf. salinicola could be used as a novel adsorbent of a biological origin against anionic and basic dyes.

Silver Nanoparticle Targets Fabricated Using Chemical Vapor Deposition Method for Differentiation of Bacteria Based on Lipidomic Profiles in Laser Desorption/Ionization Mass Spectrometry.

The global threat of numerous infectious diseases creates a great need to develop new diagnostic methods to facilitate the appropriate prescription of antimicrobial therapy. More recently, the possibility of using bacterial lipidome analysis via laser desorption/ionization mass spectrometry (LDI-MS) as useful diagnostic tool for microbial identification and rapid drug susceptibility has received particular attention because lipids are present in large quantities and can be easily extracted similar to ribosomal proteins. Therefore, the main goal of the study was to evaluate the efficacy of two different LDI techniques-matrix-assisted (MALDI) and surface-assisted (SALDI) approaches-in the classification of the closely related Escherichia coli strains under cefotaxime addition. Bacterial lipids profiles obtained by using the MALDI technique with different matrices as well as silver nanoparticle (AgNP) targets fabricated using the chemical vapor deposition method (CVD) of different AgNP sizes were analyzed by the means of different multivariate statistical methods such as principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), sparse partial least squares discriminant analysis (sPLS-DA), and orthogonal projections to latent structures discriminant analysis (OPLS-DA). The analysis showed that the MALDI classification of strains was hampered by interference from matrix-derived ions. In contrast, the lipid profiles generated by the SALDI technique had lower background noise and more signals associated with the sample, allowing E. coli to be successfully classified into cefotaxime-resistant and cefotaxime-sensitive strains, regardless of the size of the AgNPs. AgNP substrates obtained using the CVD method were used for the first time for distinguishing closely related bacterial strains based on their lipidomic profiles and demonstrate high potential as a future diagnostic tool for the detection of antibiotic susceptibility.

Advanced Mass Spectrometric Techniques for the Comprehensive Study of Synthesized Silicon-Based Silyl Organic Compounds: Identifying Fragmentation Pathways and Characterization.

The primary objective of this study was to synthesize and characterize novel silicon-based silyl organic compounds in order to gain a deeper understanding of their potential applications and interactions with other compounds. Four new artificial silyl organic compounds were successfully synthesized: 1-O-(Trimethylsilyl)-2,3,4,6-tetra-O-acetyl-ß-d-glucopyranose (compound 1), 1-[(1,1-dimethylehtyl)diphenylsilyl]-1H-indole (compound 2), O-tert-butyldiphenylsilyl-(3-hydroxypropyl)oleate (compound 3), and 1-O-tert-Butyldiphenylsilyl-myo-inositol (compound 4). To thoroughly characterize these synthesized compounds, a combination of advanced mass spectrometric techniques was employed, including nanoparticle-assisted laser desorption/ionization mass spectrometry (NALDI-MS), Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), and triple quadrupole electrospray tandem mass spectrometry (QqQ ESI-MS/MS). These analytical methods enabled the accurate identification and characterization of the synthesized silyl organic compounds, providing valuable insights into their properties and potential applications. Furthermore, the electrospray ionization-Fourier transform ion cyclotron resonance-tandem mass spectrometry (ESI-FT-ICR-MS/MS) technique facilitated the proposal of fragmentation pathways for the ionized silyl organic compounds, contributing to a more comprehensive understanding of their behavior during mass spectrometric analysis. These findings suggest that mass spectrometric techniques offer a highly effective means of investigating and characterizing naturally occurring silicon-based silyl organic compounds, with potential implications for advancing research in various fields and applications in different industries.