High Resolution GC-MS Research Articles

Exploring Pottery Function and Cooking Practices in Bronze Age Sicily: The Results of High-resolution GC-MS of Organic Residues

ABSTRACT Despite the extended application of GC-MS for detecting organic residues from archaeological ceramics, the potential of gas chromatography – high-resolution and accuracy mass spectrometry (GC-HRAMS) has not yet been fully explored. This study conducted lipid residue analysis (using an Exactive Orbitrap GC-MS system) of dolia and jars from two Early and Middle Bronze Age (2200-1450 BC) archaeological sites in south-eastern Sicily, comparing chromatograms obtained by both GC-HRAMS and GC coupled to quadrupole, low-resolution MS (GC-LRMS). The archaeological question aimed at verifying the use of the selected vessels for cooking purposes and exploring hypotheses concerning their employment in different cooking methods (boiling or roasting) based on the analysis of morphological features and burning traces on the surfaces. The results showed clear advantages of using GC-HRAMS in targeted and untargeted approaches.

Future projection of tropical cyclone genesis in the Western North pacific using high-resolution GCMs and genesis potential indices

The study employed high-resolution atmospheric general circulation models (AGCM) to simulate tropical cyclones (TCs) and evaluated two TC genesis potential indices in reflecting projected TC changes in the western North Pacific (WNP) under a warming scenario. Both indices accurately represented the seasonal variation of TC genesis frequency (TCGF) and its spatial distribution in historical simulations and observation data. The widely-used TC genesis potential index (χGPI) projected a significant increase in TCGF in response to a warmer ocean surface. However, this projection conflicted with the significant reduction in the model projection due to the dominant control of SST on the χGPI. Higher SST in remote ocean basins often over dominated the destabilization effect of in-situ warmer SST and caused more stable atmospheric conditions in the WNP, resulting in fewer TC occurrences. By contrast, the revised index (χMqGPI), which considers gross moisture condensation, projected a TCGF decrease that more accurately reflected the decreasing trend of TCGF in the warming simulations by AGCM, although the degree of reduction was smaller than that derived directly from TC detection scheme. The results suggest the plausibility of using χMqGPI, based on the results of multimodel coarse-resolution CMIP6 climate models, to project future changes in TCGF in the WNP.

MSdeCIpher: A Tool to Link Data from Complementary Ionization Techniques in High-Resolution GC-MS to Identify Molecular Ions.

Electron ionization (EI) and molecular ion-generating techniques like chemical ionization (CI) are complementary ionization methods in gas chromatography (GC)-mass spectrometry (MS). However, manual curation effort and expert knowledge are required to correctly assign molecular ions to fragment spectra. MSdeCIpher is a software tool that enables the combination of two separate datasets from fragment-rich spectra, like EI-spectra, and soft ionization spectra containing molecular ion candidates. Using high-resolution GC-MS data, it identifies and assigns molecular ions based on retention time matching, user-defined adduct/neutral loss criteria, and sum formula matching. To our knowledge, no other freely available or vendor tool is currently capable of combining fragment-rich and soft ionization datasets in this manner. The tool's performance was evaluated on three test datasets. When molecular ions are present, MSdeCIpher consistently ranks the correct molecular ion for each fragment spectrum in one of the top positions, with average ranks of 1.5, 1, and 1.2 in the three datasets, respectively. MSdeCIpher effectively reduces candidate molecular ions for each fragment spectrum and thus enables the usage of compound identification tools that require molecular masses as input. It paves the way towards rapid annotations in untargeted analysis with high-resolution GC-MS.

Phytochemical profiling, in vitro analysis for anti-inflammatory, immunomodulatory activities, structural elucidation and in silico evaluation of potential selective COX-2 and TNF-α inhibitor from Hydrilla verticillata (L.f.) Royle

Hydrilla verticillata (L.f.) Royle is a perennial aquatic plant, which exhibits nutritional as well as therapeutic properties. The present study has been carried out to evaluate anti-inflammatory and immunomodulatory activities along with in silico evaluation of potential selective COX-2 and TNF-α inhibitors from methanolic extract of H. verticillata (L.f.) Royle. The potential therapeutic compounds have been identified by high-resolution GC-MS analysis. Its capacity to inhibit inflammatory responses using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells has been explored. The anti-inflammatory properties of the plant extract were investigated by inhibiting inducible nitric oxide (NO) synthase and reduced NO generation driven by LPS on stimulated RAW 264.7 macrophage cells. Further investigation for the underlying molecular mechanism of the anti-inflammatory activity of plant extract has been carried out by molecular docking and molecular dynamics simulation approaches with COX-2 and TNF-α inhibitors ability against the most potent phytocompound phytol from the plant extract. To evaluate whether the extract causes any toxicity, the cytotoxicity test has been carried out with the Human embryonic kidney cell line (Hek-293), Mouse fibroblast (L929), human mesenchyme stem cells (hMSCs) and human breast epithelial cell line (MCF-10a). Ultimately, our findings suggest that the plant extract have great potential to reduce inflammation without causing any toxicity to normal cell. Communicated by Ramaswamy H. Sarma

Ingestion of car tire crumb rubber and uptake of associated chemicals by lumpfish (Cyclopterus lumpus)

Car tire rubber constitutes one of the largest fractions of microplastics emissions to the environment. The two main emission sources are tire wear particles (TWPs) formed through abrasion during driving and runoff of crumb rubber (CR) granulate produced from end-of-life tires that is used as infill on artificial sports fields. Both tire wear particles and crumb rubber contain a complex mixture of metal and organic chemical additives, and exposure to both the particulate forms and their leachates can cause adverse effects in aquatic species. An understanding of the exposure pathways and mechanisms of toxicity are, however, scarce. While the most abundant metals and organic chemicals in car tire rubber have multiple other applications, para-phenylenediamines (PDs) are primarily used as rubber antioxidants and were recently shown to cause negative effects in aquatic organisms. The present study investigated the responses of the marine lumpfish (Cyclopterus lumpus) to crumb rubber exposure in a controlled feeding experiment. Juvenile fish were offered crumb rubber particles with their feed for 1 week, followed by 2 weeks of depuration. Crumb rubber particle ingestion occurred in >75% of exposed individuals, with a maximum of 84 particles observed in one specimen. Gastrointestinal tract retention times varied, with some organisms having no crumb rubber particles and others still containing up to 33 crumb rubber particles at the end of the experiment. Blood samples were analyzed for metals and organic chemicals, with ICP-MS analysis revealing there was no uptake of metals by the exposed fish. Interestingly, high resolution GC-MS analysis indicated that uptake of PDs into lumpfish blood was proportionate to the number of ingested CR particles. Three of the PDs found in blood were the same as those identified in the additive mixture Vulkanox3100. N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) was the most concentrated PD in both the crumb rubber and lumpfish blood. The transformation product 6PPD-quinone was detected in the rubber material, but not in the blood. This study demonstrates that PDs are specific and bioavailable chemicals in car tire rubber that have the potential to serve as biomarkers of recent exposure to tire chemicals, where simple blood samples could be used to assess recent tire chemical exposure in vertebrates, including humans.

Evaluation of anti-inflammatory activity and identification of a monoterpenoidhydroxylactone (-)-loliolide from Tribulus terrestris L.: In-vivo and In-silico Approaches

The present study aimed to determine the anti-inflammatory effects of Tribulusterrestris L (aerial parts) and to identify the anti-inflammatory agents from active extracts and fractions together with in silico prediction of their mechanism of action, pharmacokinetics, and toxicity profile. The anti-inflammatory activity was evaluated for Dichloromethane, methanol, and its fractions (chloroform, ethyl acetate, n-butanol by Carrageenan induced rat paw edema. The phytoconstituents of the anti-inflammatory active fraction (chloroform fraction of methanol extract) was identified using Thermo Scientific TM DFS high-resolution GC-MS. The GC-MS analysis revealed 13 compounds from which (-)-loliolide was the most abundant compound by peak area. It was docked, using Autodock 4.0 onto three Key enzymes involved in the inflammatory cascade (Cyclooxygenase (COX-1 &2) and 5-lipooxygenase (5-LOX)). It displayed binding energies; -6.98 kcal/mole (COX-1) compared to -6.83kcal/mole for standard, -6.64 kcal/mole (COX-2) compared to -6.88 kcal/mole for standard and -5.25 kcal/mole (5-LOX) compared to -6.89 kcal/mole for standard. Toxicity risks, drug likeliness, and pharmacokinetic properties were studied by different online open-source programs. Good binding energy, drug-likeness, and efficient pharmacokinetic parameters of (-)-loliolide suggest it as a good inhibitor, however, further research is needed.

Trace Elements and Persistent Organic Pollutants in Unhatched Loggerhead Turtle Eggs from an Emerging Nesting Site along the Southwestern Coasts of Italy, Western Mediterranean Sea

Marine pollution is one of the major threats affecting loggerhead turtles, which due to their long life span, highly migratory behavior, and carnivorous diet, may be exposed to elevated levels of toxic elements throughout their life. The transfer of chemicals from mothers to their offspring is of particular conservation concern because it may affect embryonic development and hatching success. In this study, the concentrations of 16 toxic and potentially toxic trace elements, 6 indicator polychlorinated biphenyls (PCBs), and organochlorine pesticide residues (OCPs) were determined in 138 eggs from 46 loggerhead turtle nests laid during the 2021 nesting season in Campania, Italy, western Mediterranean Sea. The possible impact of pollutant levels on hatching success and early embryonic death was also investigated. Trace element analysis was performed using an ICP-MS, except for mercury, which was determined using a Direct Mercury Analyzer® (DMA). PCBs and OCPs were analyzed with high-resolution gas chromatography coupled with high-resolution mass spectrometry (HRGC-HRMS) and gas chromatography tandem quadrupole mass spectrometry GC-MS /MS, respectively. The concentrations of essential elements in the eggs were higher than those of non-essential elements. In addition, the highly chlorinated PCBs (153, 138, and 180) contributed the most to the total PCBs, while OCPs were not detected. No correlations were found between contaminant concentrations and reproductive parameters (hatching success and no obvious embryos). The results obtained suggest that the levels of contaminants found in the eggs do not affect the reproductive success of the species in the study area.

Chemical composition and biological activities of volatile oil of the stem of Dombeya buettneri K. Schum. (Sterculiaceae)

Essential oil, obtained from the stem of Dombeya buettneri and characterized by high resolution GC–MS was tested for antimicrobial (using broth dilution method) and antioxidant (using spectrophotometric methods: DPPH, FRAP and ABTS) properties.Forty-three (43) essential oil components were detected which account for 96.8% of the total oil content comprising mainly: Non-terpene derivatives (31.8%), Apocarotenes (24.3%), Sesquiterpenoids (15.3%), Sesquiterpene hydrocarbons (14.4%), Monoterpenoids (10.1%) and Monoterpene hydrocarbons (0.9%). The major identified compounds in the oil were (E)-geranylacetone (14.8%), δ-cadinene (8.9%), n-hexadecane (7.8%), Tetradecanal (6.2%), β-ionone (4.9%), Borneol (4.2%), Viridiflorol (3.5%), Guaiol (3.4%), caryophyllene oxide (3.4%), Palustrol (2.5%) and Spathulenol (2.5%).The oil displayed antibacterial and antifungal activities on Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Candida albicans ATCC 18804 with respective Minimum Inhibitory Concentration (MIC) of 6.25, 12.5 and 12.5%v/v. The Minimum Bactericidal/Fungicidal Concentrations on the test organisms ranged from 12.5 to 25.0%v/v. The antioxidant assay by DPPH showed a concentration dependent values of 8.0993±0.827 at 25 mg/mL, 14.7657±0.8151 and 19.449±0.6678 at 100 mg/mL with good IC50 value of 1098 µg/mL as compared with reference ascorbic acid standard with IC50 of 23.52 µg/mL. The Ferric reducing antioxidant assay (FRAP) showed activity at concentration of 0.076713±0.001227mg/FeSO4Equiv./g, while ABTS showed an activity at 0.3776±0.0025 mg AA Equiv./g with respect to the standards.The current study showed that the volatile oil of Dombeya buettneri stem possess good antioxidant and antimicrobial properties that could be utilized for cosmetic and pharmaceutical health benefits.

High-Throughput Profiling of Metabolic Phenotypes Using High-Resolution GC-MS.

Metabolite profiling provides insights into the metabolic signatures, which themselves are considered as phonotypes closely related to the agronomic and phenotypic traits such as yield, nutritional values, stress resistance, and nutrient use efficiency. GC-MS is a sensitive and high-throughput analytical platform and has been proved to be a vital tool for the analysis of primary metabolism to provide an overview of cellular and organismal metabolic status. The potential of GC-MS metabolite profiling as a tool for detecting metabolic changes in plants grown in a high-throughput plant phenotyping platform was explored. In this chapter, we describe an integrated workflow of semi-targeted GC-high-resolution (HR)-time-of-flight (TOF)-MS metabolomics with both the analytical and computational steps, focusing mainly on the sample preparation, GC-HR-TOF-MS analysis part, and data analysis for plant phenotyping efforts.

Untargeted Metabolomic Analysis of Nonvolatile and Volatile Glucosinolates in Brassicaceae.

Glucosinolates (GLSs) are a group of plant secondary metabolites mainly found in Cruciferous plants. The main hydrolysis products of GLSs, isothiocyanates (ITCs), are the bioactive metabolites that have shown plant defense and human cancer prevention properties. Untargeted metabolomic analysis of plant metabolites can uncover the profiles of these bioactive phytochemicals in specific plants and discover potential human health promoting products. We have developed an integrated metabolomic analysis method for plant samples, with specific focus on nonvolatile GLSs and volatile ITCs. In this chapter, we describe in detail the protocols, including metabolite extraction, high resolution LC-MS and GC-MS analysis, and data processing. The method is readily applicable to untargeted analysis of other nonvolatile and volatile metabolites in plants.

Evaluation of CMIP6 HighResMIP models in simulating precipitation over Central Asia

The High Resolution Model Intercomparison Project (HighResMIP) experiment within the Coupled Model Intercomparison Project Phase 6 (CMIP6), for the first time, has provided an opportunity to evaluate the performance of climate models over complex topographies. Based on the HighResMIP's historical simulations of atmospheric general circulation models, the performances of global high-resolution models, with a horizontal resolution finer than 50 km, in representing precipitation over Central Asia were evaluated using rain gauge observation datasets. All the models successfully reproduce the large precipitation regions that are located over the mountainous areas and Northern Central Asia. However, nearly all the models overestimate precipitation frequency over Central Asia and large overestimations of precipitation amount and frequency are located over the mountainous areas. Although the HighResMIP multi-model ensemble mean performs better than all individual models at simulating the spatial pattern of precipitation frequency, it is inferior to HadGEM3-GC31-HM and ECMWF-IFS-HR at simulating that of precipitation amount. The simulation performance exhibits remarkable regional differences. Over the Qilian Mountains, the relationship between precipitation and elevation is totally captured by climate models. In contrast, over the Tianshan Mountains, the models fail to simulate the decrease in precipitation frequency after elevation higher than the maximum precipitation elevation. Most models successfully reproduce the annual cycle shape of precipitation amount over the Southern Central Asia, Qilian Mountains and Tianshan Mountains, but fail to reproduce it over the Northern Central Asia. More than half of the high-resolution GCMs have a reduced bias relative to the corresponding low-resolution GCMs. The performances of most high-resolution GCMs in simulating precipitation pattern are well over the Tianshan Mountains.

Does HadGEM3-GC3.1 GCM overestimate land precipitation at high resolution? A constraint based on observed river discharge

AbstractPrevious studies showed that high-resolution GCMs overestimate land precipitation when compared against observation-based data. Particularly, high-resolution HadGEM3-GC3.1 shows a significant precipitation increase in mountainous regions, where the scarcity of gauge stations increases the uncertainty of gridded observations and reanalyses. This work evaluates such precipitation uncertainties indirectly through the assessment of river discharge, considering that an increase of ~10% in land precipitation produces ~28% more runoff when the resolution is enhanced from 1° to 0.25°, and ~50% of the global runoff is produced in 27% of global land dominated by mountains. We diagnosed the river flow by routing the runoff generated by HadGEM3-GC3.1 low- and high-resolution simulations. The river flow is evaluated using a set of 344 monitored catchments distributed around the world. We also infer the global discharge by constraining the simulations with observations following a novel approach that implies bias correction in monitored rivers with two methods, and extension of the correction to the river mouth, and along the coast. Our global discharge estimate is 47.4±1.6×103km3yr−1, which is closer to the original high-resolution estimate (50.5 × 103km3yr−1) than to the low-resolution (39.6 × 103km3yr−1). The assessment suggests that high-resolution simulations performbetter in mountainous regions, either because the better-defined orography favours the placement of precipitation in the correct catchment, leading to a more accurate distribution of runoff, or the orographic precipitation increases, reducing the dry runoff bias of coarse resolution simulations. However, high-resolution slightly increases wet biases in catchments dominated by flat terrain. The improvement of model parameterizations and tuning may reduce the remaining errors in high-resolution simulations.

Simultaneous determination of polybrominated diphenyl ethers and hexabromocyclododecane in plastic waste by short-column gas-chromatography-quadrupole mass spectrometry and electron capture detector

To avoid recycling plastic waste containing polybrominated diphenyl ethers (PBDEs) or hexabromocyclododecane (HBCD), which are listed in the Stockholm Convention on Persistent Organic Pollutants (POPs), a simple method to determine their contents at the time of waste disposal is needed. Herein, we developed a rapid analytical method using a gas chromatograph coupled with quadrupole mass spectrometry or electron capture detection to simultaneously detect PBDEs and HBCD in plastic waste. PBDEs and HBCD were ultrasonically extracted from plastic samples using toluene. The dissolved polymer matrix was then removed using n-hexane and 44% H2SO4-impregnated silica gel before analysis of the extract. A run time of less than 10 min was achieved using a custom, short GC column (5 m). The detection limits of the method were below the upper threshold of the low POP content limits defined by the Basel Convention (<1000 mg kg−1 for both PBDEs and HBCD). The accuracy of the method was confirmed by analyzing seven polymer reference materials. The determined PBDE and HBCD concentrations in most of these reference materials were within 30% of the certified values; the coefficients of variation in triplicate analysis were also within 30%. The concentrations of PBDEs and HBCD in actual plastic waste measured by this method were comparable with those obtained by more sophisticated and expensive methods, such as GC–high-resolution MS for PBDEs and liquid chromatography–tandem mass spectrometry for HBCD. Hence, the method developed herein is a less expensive alternative for identifying PBDE- and HBCD-containing wastes.

Accurate and ultrasensitive determination of 72 parent and halogenated polycyclic aromatic hydrocarbons in a variety of environmental samples via gas chromatography–triple quadrupole mass spectrometry

Polycyclic aromatic hydrocarbons (PAHs) and their halogenated derivatives (XPAHs) are ubiquitous in various environmental media. Analytical problems, however, make it difficult to accurately determine their concentrations. To develop a satisfactory analytical method suitable for a diversity of PAHs and XPAHs in multiple environmental samples, we evaluated three commercial analytical columns (DB-5MS, Select PAH, and Rxi-PAH) for better chromatographic separation and optimized the analytical conditions for gas chromatography–triple quadrupole mass spectrometry (GC-MS/MS). Comparison of the abilities of the columns to separate peaks revealed that the Rxi-PAH was the best column for both PAH and XPAH analyses. Optimization of analytical conditions for GC-MS/MS resulted in sensitivities for PAHs and XPAHs that were 4.2-fold–2600-fold higher than the sensitivities of GC-high-resolution MS (GC-HRMS) (an example of a traditional analytical method). Although there were no statistically significant differences between the instrumental detection limits (IDLs) of PAHs and XPAHs measured by GC-HRMS, the IDLs of XPAHs were significantly lower than those of PAHs when measured by GC-MS/MS. This difference could be attributed to the unique ionization patterns of XPAHs in the GC-MS/MS analysis, which suppressed background noise and increased the analytical sensitivity. Analyses of PAHs and XPAHs in grilled chicken, vehicle exhaust, sea sediment, ambient air, and indoor dust via the analytical method optimized in this study revealed that the proposed method was sufficiently sensitive, comprehensive, and versatile for risk assessment purposes, and could eliminate interferences associated with the co-elution of target PAHs and XPAHs.

Cloning, Yeast Expression, and Characterization of a β-Amyrin C-28 Oxidase (CYP716A249) Involved in Triterpenoid Biosynthesis in Polygala tenuifolia.

Polygala tenuifolia Willd. is a traditional Chinese herbal medicine that is widely used in treating nervous system disorders. Triterpene saponins in P. tenuifolia (polygala saponins) have excellent biological activity. As a precursor for the synthesis of presenegin, oleanolic acid (OA) plays an important role in the biosynthesis of polygala saponins. However, the mechanism behind the biosynthesis of polygala saponins remains to be elucidated. In this study, we found that CYP716A249 (GenBank: ASB17946) oxidized the C-28 position of β-amyrin to produce OA. Using quantitative real-time PCR, we observed that CYP716A249 had the highest expression in the roots of 2-year-old P. tenuifolia, which provided a basis for the selection of samples for gene cloning. To identify the function of CYP716A249, the strain R-BE-20 was constructed by expressing β-amyrin synthase in yeast. Then, CYP716A249 was co-expressed with β-amyrin synthase to construct the strain R-BPE-20 by using the lithium acetate method. Finally, we detected β-amyrin and OA by ultra-HPLC-Q Exactive hybrid quadrupole-Orbitrap high-resolution accurate mass spectrometry and GC-MS. The results of this study provide insights into the biosynthesis pathway of polygala saponins.

Kinetics, Mechanism, and Toxicity of Amlodipine Degradation by the UV/Chlorine Process

The UV/chlorine process, as a new type of AOP (Advanced Oxidation Process), was utilized to treat amlodipine (AML)-containing water. The influencing factors, including chlorine dose, UV intensity, solution initial pH value, and ammonia concentration, were investigated. The degradation of AML in real water and the relative contributions of OH• and Cl• were also studied. Finally, high-resolution mass spectrometry (HRMS) and GC-MS were used to identify the possible degradation products. The results demonstrated that the AML degradation process was fitted with apparent first-order kinetics. AML degradation had a positive correlation with UV intensity and chlorine dose, and a negative correlation with ammonia concentration. In the presence of ammonia nitrogen and DOM, the removal of AML from real water was reduced. OH• made a dominant percentage contribution of 55.7% to the degradation of AML. Sixteen intermediates were detected and identified. A possible degradation mechanism was also proposed. Acute toxicity tests and risk prediction both illustrated that the complete removal of AML does not guarantee the reduction of acute toxicity, but a prolonged degradation promoted the detoxification of toxic intermediates. The UV/chlorine process can be regarded to be an effective method to remove AML and reduce ecological risk.

Kinetics and Mechanism of Sucralose Degradation in Water Using UV-activated Persulfate Process

The degradation of emerging pollutant artificial sweetener sucralose (SUC) using UV/persulfate (UV/PS). The effects of several process parameters, including UV light intensity, PS dosage, pH, and anion concentration, were also investigated. The degradation products and their toxicity during the UV/PS process were further analyzed and evaluated. It is reported that, compared with single UV or PS, the degradation of SUC by UV/PS was more obvious. The degradation rate constants increased with an increase in the light intensity and PS dosage. The SUC degradation could be improved under neutral conditions. The background ions NO3- and HCO3- could inhibit the degradation process, while Cl- and SO42- ions could accelerate the process. Sixteen intermediate products were identified using high-resolution mass spectrometry (HRMS) and GC-MS. Hydroxylation, oxidation, ether cracking, and other reactions were involved. A degradation path was further proposed. Moreover, luminescent bacteria toxicity test and ECOSAR prediction showed that the intermediates with higher toxicity could be produced during UV/PS, which could pose a potential threat to the ecological environment.

Metabolic reprograming of LPS-stimulated human lung macrophages involves tryptophan metabolism and the aspartate-arginosuccinate shunt.

Lung macrophages (LM) are in the first line of defense against inhaled pathogens and can undergo phenotypic polarization to the proinflammatory M1 after stimulation with Toll-like receptor agonists. The objective of the present work was to characterize the metabolic alterations occurring during the experimental M1 LM polarization. Human LM were obtained from resected lungs and cultured for 24 hrs in medium alone or with 10 ng.mL-1 lipopolysaccharide. Cells and culture supernatants were subjected to extraction for metabolomic analysis with high-resolution LC-MS (HILIC and reverse phase -RP- chromatography in both negative and positive ionization modes) and GC-MS. The data were analyzed with R and the Worklow4Metabolomics and MetaboAnalyst online infrastructures. A total of 8,741 and 4,356 features were detected in the intracellular and extracellular content, respectively, after the filtering steps. Pathway analysis showed involvement of arachidonic acid metabolism, tryptophan metabolism and Krebs cycle in the response of LM to LPS, which was confirmed by the specific quantitation of selected compounds. This refined analysis highlighted a regulation of the kynurenin pathway as well as the serotonin biosynthesis pathway, and an involvement of aspartate-arginosuccinate shunt in the malate production. Macrophages M1 polarization is accompanied by changes in the cell metabolome, with the differential expression of metabolites involved in the promotion and regulation of inflammation and antimicrobial activity. The analysis of this macrophage immunometabolome may be of interest for the understanding of the pathophysiology of lung inflammatory disesases.

Gas chromatography–triple quadrupole mass spectrometry analysis of dioxins in soil

The applicability of gas chromatography–triple quadrupole mass spectrometry (GC–MS/MS) for determination of dioxins in soil was investigated. The analytical method was validated based on US Environmental Protection Agency (EPA) Method 1613 and European Union (EU) Regulation No. 709/2014 for selectivity, linearity of sensitivity, and instrumental limits of quantification (iLOQs). Method development commenced with determination of retention times for 17 native polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) and selection of characteristic ions from GC–MS/MS spectra. The linearity was measured using 1613 standard solutions (CS1–CS5) containing 0.5 to 200 ng/mL tetrachlorodibenzo-p-dioxin/furan (TCDD/F) congeners, 2.5 to 1000 ng/mL pentachlorodibenzo-p-dioxin/furan (PeCDD/F) to heptachlorodibenzo-p-dioxin/furan (HpCDD/F) congeners, and 20 to 2000 ng/mL octachlorodibenzo-p-dioxin/furan (OCDD/F) congeners. The correlation coefficient (R2) values ranged between 0.9990 and 0.9999, and the iLOQ values ranged from 0.052 to 0.350 pg/μL for TCDD/F congeners, with a relative standard deviation of 2.7–9.6%. The entire analytical method was verified by analysis of certified reference materials (BCR-529 and BCR-530), and the recoveries were 71.79–103.87% and 81.50–103.12%, respectively. Thus, the GC–MS/MS system provides an alternative to GC–high-resolution MS for the simultaneous determination of TCDD/F congeners in soil.

Climate classifications from regional and global climate models: Performances for present climate estimates and expected changes in the future at high spatial resolution

Climate classifications based on temperature and precipitation measurements are increasingly being used for environmental and climate change studies. Using three classification methods (Köppen, Extended Köppen, and Holdridge) and one observational dataset for present climate (CRU, Climate Research Unit), we show that GCMs have bridged the gap that led to the emergence of RCMs thirty years ago, as GCMs can now provide global climate classifications whose accuracy and precision are comparable to those of regional outputs of the RCMs. Projections of high-resolution GCMs for future climates under the assumptions of three Representative Concentration Pathways (RCP26, RCP45 and RCP85) can therefore be used as a primary source for climate change and global warming studies at high resolution. This paper provides comprehensive, model-derived climate classifications for the entire planet, using RCMs and two GCMs for present and future climate-change scenarios, and discusses how well the models actually represent the climates of the world when compared with reference, ground validation data. It turns out that both GCMs and RCMs appear still limited to provide practical estimates of the world climates even for present climate conditions. The modeling of precipitation remains the Achilles' heel of models and thus of multidimensional indices, which are very sensitive to this variable. The conclusion is that model outputs at regional scale need to be taken with extreme caution without venturing into informing policies presenting potentially large societal impacts. Nonetheless, the role of models as privileged tools to advance our scientific knowledge of the Earth's system remains undisputed.