Vaclavik, Lukáš* Dotaz Zobrazit nápovědu
The availability of rapid and reliable tools for monitoring of plants' cold tolerance is a prerequisite for research aimed at breeding of cold-tolerant crop plants. Therefore, we have tested the capacity of metabolomics-based methods employing ultra-high-performance liquid chromatography (UHPLC)-mass spectrometry and direct analysis in real time-mass spectrometry for high-throughput screening of cold tolerance in eight differentially cold-tolerant accessions of Arabidopsis thaliana. Metabolomic fingerprinting of leaf tissues was performed in methanolic extracts for (1) 6-week-old non-acclimated (NAC) plants grown at room temperature, (2) NAC plants cold-acclimated (ACC) at 4 °C for 2 weeks, and (3) cold-acclimated plants given sub-zero-temperature treatments by slow cooling at -4 °C for 8 h. The generated chromatograms and mass spectra were processed with the use of multivariate statistical analysis employing principal component analysis (PCA) and linear discriminant analysis. The PCA of metabolomic fingerprints classified the investigated A. thaliana accessions into three categories with low, intermediate, and high cold tolerance for both the cold-acclimated and the sub-zero-temperature-treated plants. This indicates the potential application of metabolomics-based fingerprinting for measuring cold tolerance in the cold-acclimated state, i.e., without treating plants at freezing temperatures that is required by currently available methods. Furthermore, we employed UHPLC coupled to the quadrupole-time-of-flight mass spectrometry to identify characteristic metabolites in ACC state and found the abundance of gluconapin and flavon-3-ol glycosides, respectively, in the cold-sensitive and the cold-tolerant accessions.
- MeSH
- Arabidopsis chemie metabolismus MeSH
- biologické markery chemie metabolismus MeSH
- hmotnostní spektrometrie metody MeSH
- metabolomika metody MeSH
- nízká teplota MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
The use of fast semi-automated method employing direct analysis in real time (DART) ion source coupled to time-of-flight mass spectrometry (TOFMS) for analysis of melamine (MEL) and cyanuric acid (CYA) in milk powder and milk based products has been demonstrated in this study. Simple sample extraction procedure employing methanol-5% aqueous formic acid mixture, which enabled disruption of melamine-cyanurate complex, was followed by direct, high-throughput (30s per run) examination of sample extracts spread on a glass rod by mass spectrometry under ambient conditions, without any prior chromatographic separation. After optimization of instrument parameter settings, limits of detection (LODs) 170 and 450microgkg(-1) were achieved for MEL and CYA, respectively. In the final phase of study, the possibility of minimizing spectral interference, thus improving method performance characteristics through the use of ultrahigh resolving power offered by Orbitrap based mass analyzer is demonstrated.
- MeSH
- hmotnostní spektrometrie metody MeSH
- kontaminace potravin analýza MeSH
- limita detekce MeSH
- mléko chemie MeSH
- prášky, zásypy, pudry analýza MeSH
- skot MeSH
- triaziny analýza MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
RATIONALE: Direct analysis in real time (DART) is a novel ionization technique that has been demonstrated in numerous applications as a useful tool for fast and convenient mass spectrometry (MS)-based analysis of complex samples. In this study, the feasibility of DART ionization coupled to a high-resolution mass spectrometer utilizing an orbitrap mass analyzer (orbitrap MS) for high-throughput analysis of antiparasitic veterinary drugs was explored. METHODS: To obtain the best DART-orbitrap MS performance, stepwise optimization of instrumental parameter settings, such as ionization gas temperature and mass resolving power, was performed. The optimized method was applied to feed and bovine milk samples previously extracted following a QuEChERS-like strategy. RESULTS: Most antiparasitic drugs could be analyzed following the described method. Positive DART ionization provided the protonated molecules [M+H](+); in negative DART ion mode, deprotonated molecules [M-H](-) were observed. As an exception, polyether ionophores could be observed as the sodiated adducts [M+Na](+). Samples of milk and feed were extracted using a modified QuEChERS method for the determination of benzimidazoles and coccidiostats respectively and quantification was carried out by matrix-matched calibration curves. CONCLUSIONS: The combination of an analysis time of less than 1 min per sample and the possibility to acquire accurate masses under high mass resolving power (HR) makes the DART-HRMS technique an effective tool for rapid qualitative screening of antiparasitic veterinary drugs. Additionally, the results obtained in this study demonstrated the feasibility of this approach to quantify target analytes at levels down to 1 µg kg(-1) for benzimidazolic compounds in milk and 0.25 mg kg(-1) for coccidiostats in chicken feed.
- MeSH
- antiparazitární látky analýza chemie MeSH
- benzimidazoly analýza chemie MeSH
- hmotnostní spektrometrie metody MeSH
- krmivo pro zvířata analýza MeSH
- mléko chemie MeSH
- rychlé screeningové testy metody MeSH
- skot MeSH
- veterinární léky analýza chemie MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The co-occurrence of deoxynivalenol-3-glucoside with its parent toxin, deoxynivalenol, has been recently documented in many cereal-based foods, especially in those produced by enzyme-catalyzed processes. The presence of this masked mycotoxin in the human diet has become an issue of health concern, mainly because of its assumed bioavailability. A selective immunoaffinity-based preconcentration strategy, followed by ultrahigh-performance liquid chromatography coupled with high-resolution orbitrap mass spectrometry, revealed that, in addition to the most common deoxynivalenol-3-glucoside, also oligoglycosylated deoxynivalenols with up to four bound hexose units were present in cereal-based products. The structure, origination, and fate of these deoxynivalenol conjugates during malt/beer production and bread baking have been thoroughly investigated. Special attention has been paid to the changes of deoxynivalenol conjugates enabled by industrial glycosidase-based enzymatic preparations. To the authors' best knowledge, this is the first study documenting the complexity of masked deoxynivalenol issue.
- MeSH
- chléb analýza MeSH
- Fusarium metabolismus MeSH
- glukosidy chemie MeSH
- jedlá semena chemie MeSH
- kontaminace potravin analýza MeSH
- molekulární struktura MeSH
- mykotoxiny chemie metabolismus MeSH
- pivo analýza MeSH
- trichotheceny chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A sensitive and accurate method utilizing ultrahigh performance liquid chromatography (U-HPLC) coupled to high resolution mass spectrometry based on orbitrap technology (orbitrapMS) for the analysis of nine 3-chloropropane-1,2-diol (3-MCPD) diesters in vegetable oils was developed. To remove the interfering triacylglycerols that induce strong matrix effects, a clean-up step on silica gel column was used. The quantitative analysis was performed with the use of deuterium-labeled internal standards. The lowest calibration levels estimated for the respective analytes ranged from 2 to 5 μg kg(-1). Good recovery values (89-120%) and repeatability (RSD 5-9%) was obtained at spiking levels of 2 and 10 mg kg(-1). As an alternative, a novel ambient desorption ionization technique, direct analysis in real time (DART), hyphenated with orbitrapMS, was employed for no separation, high-throughput, semi-quantitative screening of 3-MCPD diesters in samples obtained by chromatographic fractionation. Additionally, the levels of 3-MCPD diesters measured in reallife vegetable oil samples (palm oil, sunflower oil, rapeseed oil) using both methods are reported. Relatively good agreement of the data generated by U-HPLC-orbitrapMS and DART-orbitrapMS were observed. With regard to a low ionization yield achieved for 3-MCPD monoesters, the methods presented in this paper were not yet applicable for the analysis of these contaminants at the naturally occurring levels.
Ultra high performance liquid chromatography with quadrupole/time-of-flight mass spectrometry was applied to evaluate the potential of nontarget metabolomic fingerprinting in order to distinguish Fusarium-infected and control barley samples. First, the sample extraction and instrumental conditions were optimized to obtain the broadest possible representation of polar/medium-polar compounds occurring in extracts obtained from barley grain samples. Next, metabolomic fingerprints of extracts obtained from nine barley varieties were acquired under ESI conditions in both positive and negative mode. Each variety of barley was tested in two variants: artificially infected by Fusarium culmorum at the beginning of heading and a control group (no infection). In addition, the dynamics of barley infection development was monitored using this approach. The experimental data were statistically evaluated by principal component analysis, hierarchical clustering analysis, and orthogonal partial least-squares discriminant analysis. The differentiation of barley in response to F. culmorum infection was feasible using this metabolomics-based method. Analysis in positive mode provided a higher number of molecular features as compared to that performed under negative mode setting. However, the analysis in negative mode permitted the detection of deoxynivalenol and deoxynivalenol-3-glucoside considered as resistance-indicator metabolites in barley.
- MeSH
- analýza hlavních komponent MeSH
- Fusarium fyziologie MeSH
- hmotnostní spektrometrie MeSH
- ječmen (rod) metabolismus mikrobiologie MeSH
- metabolomika * MeSH
- metoda nejmenších čtverců MeSH
- nemoci rostlin mikrobiologie MeSH
- shluková analýza MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A combination of direct analysis in real time (DART) ionization coupled to time-of-flight mass spectrometry (TOFMS) and chemometrics was used for animal fat (lard and beef tallow) authentication. This novel instrumentation was employed for rapid profiling of triacylglycerols (TAGs) and polar compounds present in fat samples and their mixtures. Additionally, fat isolated from pork, beef, and pork/beef admixtures was analyzed. Mass spectral records were processed by principal component analysis (PCA) and stepwise linear discriminant analysis (LDA). DART-TOFMS profiles of TAGs were found to be more suitable for the purpose of discrimination among the examined fat types as compared to profiles of polar compounds. The LDA model developed using TAG data enabled not only reliable classification of samples representing neat fats but also detection of admixed lard and tallow at adulteration levels of 5 and 10% (w/w), respectively. The presented approach was also successfully applied to minced meat prepared from pork and beef with comparable fat content. Using the DART-TOFMS TAG profiles of fat isolated from meat mixtures, detection of 10% pork added to beef and vice versa was possible.
- MeSH
- diskriminační analýza MeSH
- hmotnostní spektrometrie přístrojové vybavení metody MeSH
- maso analýza MeSH
- prasata MeSH
- řízení kvality MeSH
- skot MeSH
- triglyceridy analýza MeSH
- tuky chemie MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
The development and use of a fast method employing a direct analysis in real time (DART) ion source coupled to high-resolution time-of-flight mass spectrometry (TOFMS) for the quantitative analysis of caffeine in various coffee samples has been demonstrated in this study. A simple sample extraction procedure employing hot water was followed by direct, high-throughput (<1 min per run) examination of the extracts spread on a glass rod under optimized conditions of ambient mass spectrometry, without any prior chromatographic separation. For quantification of caffeine using DART-TOFMS, an external calibration was used. Isotopically labeled caffeine was used to compensate for the variations of the ion intensities of caffeine signal. Recoveries of the DART-TOFMS method were 97% for instant coffee at the spiking levels of 20 and 60 mg/g, respectively, while for roasted ground coffee, the obtained values were 106% and 107% at the spiking levels of 10 and 30 mg/g, respectively. The repeatability of the whole analytical procedure (expressed as relative standard deviation, RSD, %) was <5% for all tested spiking levels and matrices. Since the linearity range of the method was relatively narrow (two orders of magnitude), an optimization of sample dilution prior the DART-TOFMS measurement to avoid saturation of the detector was needed.
This paper describes a single-laboratory validation of a liquid chromatography-diode array detection (LC-DAD) method for quantification of 12 major cannabinoids in Cannabis dried plant materials, concentrates, and oils. The method met Standard Method Performance Requirements for quantitative analysis of cannabinoids in Cannabis concentrates and Cannabis dried plant materials. The LOQs were in the range 0.003-0.10% (w/w), depending on the analyte and matrix. Spike recoveries were between 96.7 and 101.3% with relative SDs (RSDs) ≤2.3%. Precision expressed as repeatability and intermediate precision was within 0.3-4.8 and 1.1-5.1%, respectively. The chromatographic separation conditions used in this versatile method are compatible with both DAD-UV and MS detection. During method validation, high-resolution quadrupole time-of-flight MS was employed as a secondary detector (connected in series to the LC-DAD instrument) to provide high confidence identification of target analytes and as a tool for monitoring other cannabinoids for which reference standards were not available. The obtained results demonstrate applicability of the method to quantitative analysis of important cannabinoids in dried plants, concentrates, and oils. Limited data were generated for a food matrix (Cannabis-containing cookies) using this method with LC coupled to a compact single quadrupole mass spectrometer.
INTRODUCTION: SARS-CoV-2 respiratory infection is associated with significant morbidity and mortality, especially in hospitalized high-risk patients. We aimed to evaluate the effects of treatment options (vitamin D, anticoagulation, isoprinosine, ivermectin) on hospital mortality in non-vaccinated patients during the 2021 spring wave in the Czech Republic. METHODS: Initially, 991 patients hospitalized in the period January 1, 2021, to March 31, 2021, with PCR-confirmed SARS-CoV-2 acute respiratory infection in two university and five rural hospitals were included in the study. After exclusion of patients with an unknown outcome, a total of 790 patients entered the final analysis. The effects of different treatments were assessed in this cohort by means of propensity score matching. RESULTS: Of the 790 patients, 282 patients died in the hospital; 37.7% were male and 33.3% were female. Age, sex, state of the disease, pneumonia, therapy, and several comorbidities were matched to simulate a case-control study. For anticoagulation treatment, 233 cases (full-dose) vs. 233 controls (prophylactic dose) were matched. The difference in mortality was significant in 16 of the 50 runs. For the treatment with isoprinosine, ivermectin, and vitamin D, none of the 50 runs led to a significant difference in hospital mortality. CONCLUSION: Prophylactic-dose anticoagulation treatment in our study was found to be beneficial in comparison with the full dose. Supplementation with vitamin D did not show any meaningful benefit in terms of lowering the hospital mortality. Neither ivermectin nor, isoprinosine was found to significantly decrease hospital mortality.
- MeSH
- antikoagulancia terapeutické užití MeSH
- COVID-19 * MeSH
- inosin pranobex * MeSH
- ivermektin terapeutické užití MeSH
- lidé MeSH
- retrospektivní studie MeSH
- SARS-CoV-2 MeSH
- studie případů a kontrol MeSH
- tendenční skóre MeSH
- vitamin D terapeutické užití MeSH
- vitaminy MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
