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In vivo NMR is evolving into an important tool to understand biological processes and environmental responses. Current approaches use flow systems to sustain the organisms with oxygenated water and food (e.g., algae) inside the NMR. However, such systems have the potential to leak and clog (potentially damaging costly hardware), require large volumes of media, and multiple expensive HPLC pumps. The proposed "oxygenation system", uses a simple "double slit" adapter and a single air/oxygen flow line into the NMR. The design is especially suited to larger diameter probes given that standard flow systems would require higher flow rates thus amplifying the potential and impact of leaks/clogs. Traditionally, in vivo NMR of small organisms (e.g., Daphnia) have required 2D NMR in combination with 13C enrichment to overcome susceptibility distortions and provide information rich metabolic profiles. Here Daphnia magna, Eisenia fetida and Artemia franciscana are used to demonstrate the potential of the oxygenation system. Survivability tests and 1H time-resolved monitoring were first performed on D. magna, while E. fetida contained enough biomass to permit 1H-13C HSQC, 13C-1H HETCOR and 31P NMR without isotopic enrichment. Finally, STOCSY of 1D 13C NMR was used to follow the growth of A. franciscana (without 13C enrichment) for 48 h after birth, which helps visualize trends across a series of 1D in vivo data. In summary, application of the oxygenation system toward larger diameter probes allows the collection of NMR data without enrichment, offering a promising solution to better understand processes in vivo.
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Artemia , Daphnia , Espectroscopía de Resonancia Magnética , Oxígeno , Animales , Oxígeno/metabolismo , Oxígeno/química , Oxígeno/análisis , Oligoquetos/metabolismo , Análisis Costo-Beneficio , SolucionesRESUMEN
Forest soils play a critical role in carbon (C) reservoirs and climate change mitigation globally. Exploring the driving factors of soil organic carbon (SOC) concentration and stability in forests on a large spatial scale can help us evaluate the role of forest soils in regulating C sequestration. Based on SOC quantification and solid-state 13C nuclear magnetic resonance spectroscopy, we investigated the SOC concentration and SOC chemical stability (indicated by alkyl-to-O-alkyl ratio and hydrophobic-to-hydrophilic ratio) in top 0-5 and 5-10 cm soils from 65 Chinese natural forest sites and explored their driving factors. Results showed that SOC concentration in 0-5 cm soils were highest in mixed forests but SOC chemical stability in 0-5 cm soils were highest in coniferous forests, while SOC concentration and chemical stability in 5-10 cm soil layers did not differ across forest types. SOC concentration in 0-5 cm was directly related to soil pH and soil bacterial diversity. Structural equation models showed that aridity indirectly affected SOC concentration in 0-5 cm by directly affecting soil pH. While SOC chemical stability in 0-5 cm soils was higher with increased aridity. According to the correlations, the potential mechanisms could be attributed to higher proportion of coniferous forests in more arid forest sites, lower relative abundance of O-alkyl C, higher MgO and CaO contents, and higher bacterial diversity in soils from more arid forest sites. Our study reveals the important role of aridity in mediating SOC concentration and chemical stability in top 0-5 cm soils in Chinese natural forests on a large-scale field investigation. These results will help us better understand the different mechanisms underlying SOC concentration and stability in forests and assess the feedback of forest SOC to future climate change.
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Carbono , Bosques , Suelo , Suelo/química , China , Carbono/análisis , Cambio Climático , Secuestro de Carbono , Monitoreo del Ambiente , Pueblos del Este de AsiaRESUMEN
Carbon influences the evolution and functioning of plants and their roots. Previous work examining a small number of commonly measured root traits has revealed a global multidimensionality of the resource economics traits in fine roots considering carbon as primary currency but without considering the diversity of carbon-related traits. To address this knowledge gap, we use data from 66 tree species from a tropical forest to illustrate that root economics space co-varies with a novel molecular-level traits space based on nuclear magnetic resonance. Thinner fine roots exhibit higher proportions of carbohydrates and lower diversity of molecular carbon than thicker roots. Mass-denser fine roots have more lignin and aromatic carbon compounds but less bioactive carbon compounds than lighter roots. Thus, the transition from thin to thick fine roots implies a shift in the root carbon economy from 'do-it-yourself' soil exploration to collaboration with mycorrhizal fungi, while the shift from light to dense fine roots emphasizes a shift from acquisitive to conservative root strategy. We reveal a previously undocumented role of molecular-level carbon traits that potentially undergird the multidimensional root economics space. This finding offers new molecular insight into the diversity of root form and function, which is fundamental to our understanding of plant evolution, species coexistence and adaptations to heterogeneous environments.
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Carbono , Raíces de Plantas , Árboles , Raíces de Plantas/metabolismo , Raíces de Plantas/genética , Carbono/metabolismo , Árboles/metabolismo , BosquesRESUMEN
Environmental pollution is escalating due to rapid global development that often prioritizes human needs over planetary health. Despite global efforts to mitigate legacy pollutants, the continuous introduction of new substances remains a major threat to both people and the planet. In response, global initiatives are focusing on risk assessment and regulation of emerging contaminants, as demonstrated by the ongoing efforts to establish the UN's Intergovernmental Science-Policy Panel on Chemicals, Waste, and Pollution Prevention. This review identifies the sources and impacts of emerging contaminants on planetary health, emphasizing the importance of adopting a One Health approach. Strategies for monitoring and addressing these pollutants are discussed, underscoring the need for robust and socially equitable environmental policies at both regional and international levels. Urgent actions are needed to transition toward sustainable pollution management practices to safeguard our planet for future generations.
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Pharmaceuticals are found in aquatic environments due to their widespread use and environmental persistence. To date, a range of impairments to aquatic organisms has been reported with exposure to pharmaceuticals; however, further comparisons of their impacts across different species on the molecular level are needed. In the present study, the crustacean Daphnia magna and the freshwater fish Japanese medaka, common model organisms in aquatic toxicity, were exposed for 48 h to the common analgesics acetaminophen (ACT), diclofenac (DCF), and ibuprofen (IBU) at sublethal concentrations. A targeted metabolomic-based approach, using liquid chromatography-tandem mass spectrometry to quantify polar metabolites from individual daphnids and fish was used. Multivariate analyses and metabolite changes identified differences in the metabolite profile for D. magna and medaka, with more metabolic perturbations for D. magna. Pathway analyses uncovered disruptions to pathways associated with protein synthesis and amino acid metabolism with D. magna exposure to all three analgesics. In contrast, medaka exposure resulted in disrupted pathways with DCF only and not ACT and IBU. Overall, the observed perturbations in the biochemistry of both organisms were different and consistent with assessments using other endpoints reporting that D. magna is more sensitive to pollutants than medaka in short-term studies. Our findings demonstrate that molecular-level responses to analgesic exposure can reflect observations of other endpoints, such as immobilization and mortality. Thus, environmental metabolomics can be a valuable tool for selecting sentinel species for the biomonitoring of freshwater ecosystems while also uncovering mechanistic information. Environ Toxicol Chem 2024;43:1339-1351. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Acetaminofén , Daphnia , Diclofenaco , Ibuprofeno , Metabolómica , Oryzias , Contaminantes Químicos del Agua , Animales , Oryzias/metabolismo , Daphnia/efectos de los fármacos , Daphnia/metabolismo , Acetaminofén/toxicidad , Ibuprofeno/toxicidad , Contaminantes Químicos del Agua/toxicidad , Diclofenaco/toxicidad , Daphnia magnaRESUMEN
While microplastics have been recently detected in human blood and the placenta, their impact on human health is not well understood. Using a mouse model of environmental exposure during pregnancy, our group has previously reported that exposure to polystyrene micro- and nanoplastics throughout gestation results in fetal growth restriction. While polystyrene is environmentally relevant, polyethylene is the most widely produced plastic and amongst the most commonly detected microplastic in drinking water and human blood. In this study, we investigated the effect of maternal exposure to polyethylene micro- and nanoplastics on fetal growth and placental function. Healthy, pregnant CD-1 dams were divided into three groups: 106 ng/L of 740-4990 nm polyethylene with surfactant in drinking water (n = 12), surfactant alone in drinking water (n = 12) or regular filtered drinking water (n = 11). At embryonic day 17.5, high-frequency ultrasound was used to investigate the placental and fetal hemodynamic responses following exposure. While maternal exposure to polyethylene did not impact fetal growth, there was a significant effect on placental function with a 43% increase in umbilical artery blood flow in the polyethylene group compared to controls (p < 0.01). These results suggest polyethylene has the potential to cause adverse pregnancy outcomes through abnormal placental function.
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Agua Potable , Placenta , Humanos , Embarazo , Femenino , Placenta/irrigación sanguínea , Microplásticos , Plásticos , Exposición Materna/efectos adversos , Polietileno/toxicidad , Poliestirenos , Desarrollo Fetal , Resultado del Embarazo , Hemodinámica , Retardo del Crecimiento Fetal , TensoactivosRESUMEN
Benchtop NMR provides improved accessibility in terms of cost, space, and technical expertise. In turn, this encourages new users into the field of NMR spectroscopy. Unfortunately, many interesting samples in education and research, from beer to whole blood, contain significant amounts of water that require suppression in 1H NMR in order to recover sample information. However, due to the significant reduction in chemical shift dispersion in benchtop NMR systems, the sample signals are much closer to the water resonance compared to those in a corresponding high-field NMR spectrum. Therefore, simply translating solvent suppression experiments intended for high-field NMR instruments to benchtop NMR systems without careful consideration can be problematic. In this study, the effectiveness of several popular water suppression schemes was evaluated for benchtop NMR applications. Emphasis is placed on pulse sequences with no, or few, adjustable parameters making them easy to implement. These fall into two main categories: (1) those based on Pre-SAT including Pre-SAT, PURGE, NOESY-PR, and g-NOESY-PR and (2) those based on binomial inversion including JRS and W5-WATERGATE. Among these schemes, solvent suppression sequences based on Pre-SAT offer a general approach for easy solvent suppression for samples with higher analyte concentrations (sucrose standard and Redbull™). However, for human urine, binomial-like sequences were required. In summary, it is demonstrated that highly efficient water suppression approaches can be implemented on benchtop NMR systems in a simple manner, despite the limited spectral dispersion, further illustrating the potential for widespread implementation of these approaches in education and research.
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In recent years there has been a renewed interest in benchtop NMR. Given their lower cost of ownership, smaller footprint, and ease of use, they are especially suited as an educational tool. Here, a new experiment targeted at upper-year undergraduates and first-year graduate students follows the conversion of D-glucose into ethanol at low-field. First, high and low-field data on D-glucose are compared and students learn both the Hz and ppm scales and how J-coupling is field-independent. The students then acquire their own quantitative NMR datasets and perform the quantification using an Electronic Reference To Access In Vivo Concentration (ERETIC) technique. To our knowledge ERETIC is not currently taught at the undergraduate level, but has an advantage in that internal standards are not required; ideal for following processes or with future use in flow-based benchtop monitoring. Using this quantitative data, students can relate a simple chemical process (fermentation) back to more complex topics such as reaction kinetics, bridging the gaps between analytical and physical chemistry. When asked to reflect on the experiment, students had an overwhelmingly positive experience, citing agreement with learning objectives, ease of understanding the protocol, and enjoyment. Each of the respondents recommended this experiment as a learning tool for others. This experiment has been outlined for other instructors to utilize in their own courses across institutions, with the hope that a continued expansion of low-field NMR will increase accessibility and learning opportunities at the undergraduate level.
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Espectroscopía de Resonancia Magnética , Espectroscopía de Resonancia Magnética/métodos , Etanol/química , Glucosa/análisis , Estudiantes , Humanos , UniversidadesRESUMEN
Understanding environmental change is challenging and requires molecular-level tools to explain the physicochemical phenomena behind complex processes. Nuclear magnetic resonance (NMR) spectroscopy is a key tool that provides information on both molecular structures and interactions but is underutilized in environmental research because standard "high-field" NMR is financially and physically inaccessible for many and can be overwhelming to those outside of disciplines that routinely use NMR. "Low-field" NMR is an accessible alternative but has reduced sensitivity and increased spectral overlap, which is especially problematic for natural, heterogeneous samples. Therefore, the goal of this study is to investigate and apply innovative experiments that could minimize these challenges and improve low-field NMR analysis of environmental and biological samples. Spectral simplification (JRES, PSYCHE, singlet-only, multiple quantum filters), selective detection (GEMSTONE, DREAMTIME), and heteronuclear (reverse and CH3/CH2/CH-only HSQCs) NMR experiments are tested on samples of increasing complexity (amino acids, spruce resin, and intact water fleas) at-high field (500 MHz) and at low-field (80 MHz). A novel experiment called Doubly Selective HSQC is also introduced, wherein 1H signals are selectively detected based on the 1H and 13C chemical shifts of 1H-13C J-coupled pairs. The most promising approaches identified are the selective techniques (namely for monitoring), and the reverse and CH3-only HSQCs. Findings ultimately demonstrate that low-field NMR holds great potential for biological and environmental research. The multitude of NMR experiments available makes NMR tailorable to nearly any research need, and low-field NMR is therefore anticipated to become a valuable and widely used analytical tool moving forward.
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Aminoácidos , Espectroscopía de Resonancia MagnéticaRESUMEN
Maternal exposure to microplastics and nanoplastics has been shown to result in fetal growth restriction in mice. In this study, we investigated the placental and fetal hemodynamic responses to plastics exposure in mice using high-frequency ultrasound. Healthy, pregnant CD-1 dams were given either 106 ng/L of 5 µm polystyrene microplastics or 106 ng/L of 50 nm polystyrene nanoplastics in drinking water throughout gestation and were compared with controls. Maternal exposure to both microplastics and nanoplastics resulted in evidence of placental dysfunction that was highly dependent on the particle size. The umbilical artery blood flow increased by 48% in the microplastic-exposed group and decreased by 25% in the nanoplastic-exposed group compared to controls (p < 0.05). The microplastic- and nanoplastic-exposed fetuses showed a significant decrease in the middle cerebral artery pulsatility index of 10% and 13%, respectively, compared to controls (p < 0.05), indicating vasodilation of the cerebral circulation, a fetal adaptation that is part of the brain sparing response to preserve oxygen delivery. Hemodynamic markers of placental dysfunction and fetal hypoxia were more pronounced in the group exposed to polystyrene nanoplastics, suggesting nanoplastic exposure during human pregnancy has the potential to disrupt fetal brain development, which in turn may cause suboptimal neurodevelopmental outcomes.
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Microplásticos , Plásticos , Embarazo , Femenino , Humanos , Animales , Ratones , Poliestirenos/toxicidad , Placenta/irrigación sanguínea , Desarrollo FetalRESUMEN
Industrial wastewater effluents are a major source of chemicals in aquatic environments, and many of these chemicals may negatively impact aquatic life. In this study, the crustacean Daphnia magna, a common model organism in ecotoxicity studies, was exposed for 48 h to nine different industrial effluent samples from manufacturing facilities associated with the production of plastics, polymers, and coating products at a range of dilutions: 10, 25, 50, 100% (undiluted). A targeted metabolomic-based approach using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to quantify polar metabolites from individual daphnids that survived the 48 h exposure. Multivariate analyses and metabolite changes revealed metabolic perturbations across all effluent samples studied, with non-monotonic responses and both up and downregulation relative to the unexposed control. Pathway analyses indicated the disruption of similar and distinct pathways, mostly connected to protein synthesis, amino acid metabolism, and antioxidant processes. Overall, we observed disruptions in Daphnia biochemistry that were similar across the effluent samples, but with unique features for each effluent sample. Additionally, non-monotonic heightened responses suggested additive and/or synergistic interactions between the chemicals within the industrial effluents. These findings demonstrate that targeted metabolomic approaches are a powerful tool for the biomonitoring of aquatic ecosystems in the context of complex mixtures, such as industrial wastewater effluents.
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Daphnia magna , Contaminantes Químicos del Agua , Animales , Aguas Residuales/toxicidad , Antioxidantes/metabolismo , Polímeros , Aminoácidos/metabolismo , Cromatografía Liquida , Ecosistema , Espectrometría de Masas en Tándem , Metabolómica , Daphnia , Contaminantes Químicos del Agua/análisisRESUMEN
HR-MAS NMR is a powerful tool, capable of monitoring molecular changes in intact heterogeneous samples. However, one of the biggest limitations of 1H NMR is its narrow spectral width which leads to considerable overlap in complex natural samples. DREAMTIME NMR is a highly selective technique that allows users to isolate suites of metabolites from congested spectra. This permits targeted metabolomics by NMR and is ideal for monitoring specific processes. To date, DREAMTIME has only been employed in solution-state NMR, here it is adapted for HR-MAS applications. At high spinning speeds (>5 kHz), DREAMTIME works with minimal modifications. However, spinning over 3-4 kHz leads to cell lysis, and if maintaining sample integrity is necessary, slower spinning (<2.5 kHz) is required. Very slow spinning (≤500 Hz) is advantageous for in vivo analysis to increase organism survival; however, sidebands from water pose a problem. To address this, a version of DREAMTIME, termed DREAMTIME-SLOWMAS, is introduced. Both techniques are compared at 2500, 500, and 50 Hz, using ex vivo worm tissue. Following this, DREAMTIME-SLOWMAS is applied to monitor key metabolites of anoxic stress in living shrimp at 500 Hz. Thus, standard DREAMTIME works well under MAS conditions and is recommended for samples reswollen in D2O or spun >2500 Hz. For slow spinning in vivo or intact tissue samples, DREAMTIME-SLOWMAS provides an excellent way to target process-specific metabolites while maintaining sample integrity. Overall, DREAMTIME should find widespread application wherever targeted molecular information is required from complex samples with a high degree of spectral overlap.
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Imagen por Resonancia Magnética , Agua , Animales , Espectroscopía de Resonancia Magnética/métodos , Crustáceos , MetabolómicaRESUMEN
INTRODUCTION: Plastics used in everyday materials accumulate as waste in the environment and degrade over time. The impacts of the resulting particulate micro- and nanoplastics on human health remain largely unknown. In pregnant mice, we recently demonstrated that exposure to nanoplastics throughout gestation and during lactation resulted in changes in brain structure detected on MRI. One possible explanation for this abnormal postnatal brain development is altered fetal brain metabolism. OBJECTIVES: To determine the effect of maternal exposure to nanoplastics on fetal brain metabolism. METHODS: Healthy pregnant CD-1 mice were exposed to 50 nm polystyrene nanoplastics at a concentration of 106 ng/L through drinking water during gestation. Fetal brain samples were collected at embryonic day 17.5 (n = 18-21 per group per sex) and snap-frozen in liquid nitrogen. Magic angle spinning nuclear magnetic resonance was used to determine metabolite profiles and their relative concentrations in the fetal brain. RESULTS: The relative concentrations of gamma-aminobutyric acid (GABA), creatine and glucose were found to decrease by 40%, 21% and 30% respectively following maternal nanoplastic exposure when compared to the controls (p < 0.05). The change in relative concentration of asparagine with nanoplastic exposure was dependent on fetal sex (p < 0.005). CONCLUSION: Maternal exposure to polystyrene nanoplastics caused abnormal fetal brain metabolism in mice. The present study demonstrates the potential impacts of nanoplastic exposure during fetal development and motivates further studies to evaluate the risk to human pregnancies.
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Microplásticos , Poliestirenos , Embarazo , Humanos , Femenino , Animales , Ratones , Exposición Materna/efectos adversos , Metabolómica , EncéfaloRESUMEN
Environmental metabolomics provides insight into how anthropogenic activities have an impact on the health of an organism at the molecular level. Within this field, in vivo NMR stands out as a powerful tool for monitoring real-time changes in an organism's metabolome. Typically, these studies use 2D 13C-1H experiments on 13C-enriched organisms. Daphnia are the most studied species, given their widespread use in toxicity testing. However, with COVID-19 and other geopolitical factors, the cost of isotope enrichment increased ~6-7 fold over the last two years, making 13C-enriched cultures difficult to maintain. Thus, it is essential to revisit proton-only in vivo NMR and ask, "Can any metabolic information be obtained from Daphnia using proton-only experiments?". Two samples are considered here: living and whole reswollen organisms. A range of filters are tested, including relaxation, lipid suppression, multiple-quantum, J-coupling suppression, 2D 1H-1H experiments, selective experiments, and those exploiting intermolecular single-quantum coherence. While most filters improve the ex vivo spectra, only the most complex filters succeed in vivo. If non-enriched organisms must be used, then, DREAMTIME is recommended for targeted monitoring, while IP-iSQC was the only experiment that allowed non-targeted metabolite identification in vivo. This paper is critically important as it documents not just the experiments that succeed in vivo but also those that fail and demonstrates first-hand the difficulties associated with proton-only in vivo NMR.
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COVID-19 , Daphnia , Animales , Daphnia/metabolismo , Protones , Espectroscopía de Resonancia Magnética , Imagen por Resonancia Magnética , MetabolómicaRESUMEN
Environmental metabolomics is a promising approach to study pollutant impacts to target organisms in both terrestrial and aquatic environments. To this end, both nuclear magnetic resonance (NMR)- and mass spectrometry (MS)-based methods are used to profile amino acids in different environmental metabolomic studies. However, these two methods have not been compared directly which is an important consideration for broader comparisons in the environmental metabolomics field. We compared the quantification of 18 amino acids in the tissue extracts of Daphnia magna, a common model organism used in both ecotoxicology and ecology, using both 1H NMR spectroscopy and liquid chromatography with tandem MS (LC-MS/MS). 1H NMR quantification of amino acids agreed with the LC-MS/MS quantification for 17 of 18 amino acids measured. We also tested both quantitative methods in a D. magna sub-lethal exposure study to copper and lithium. Again, both NMR and LC-MS/MS measurements showed agreement. We extended our analyses with extracts from the earthworm Eisenia fetida and the plant model Nicotiana tabacum. The concentrations of amino acids by both 1H NMR and LC-MS/MS, agreed and demonstrated the robustness of both techniques for quantitative metabolomics. These findings demonstrate the compatibility of these two analytical platforms for amino acid profiling in environmentally relevant model organisms and emphasizes that data from either method is robust for comparisons across studies to further build the knowledge base related to pollutant exposure impacts and toxic responses of diverse environmental organisms.
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Phthalic acid esters (PAEs) are a class of chemicals that are usually incorporated as additives in the manufacturing of plastics. PAEs are not covalently bound to the material matrix and can, consequently, be leached into the environment. PAEs have been reported to act as endocrine disruptors, neurotoxins, metabolic stressors, and immunotoxins to aquatic organisms but there is a lack of information regarding the impact of sub-lethal concentrations to target organisms. The freshwater crustacean Daphnia magna, a commonly used model organism in aquatic toxicity, was exposed to four phthalate pollutants: dimethyl phthalate (DMP), diethyl phthalate (DEP), monomethyl phthalate (MMP), and monoethyl phthalate (MEP). Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was employed in a targeted metabolomic approach to quantify polar metabolites extracted from a single Daphnia body. Individual metabolite percent changes and hierarchical clustering heatmap analysis showed unique metabolic profiles for each phthalate pollutant. Metabolite percent changes were mostly downregulated or presented opposing responses for the low and high concentrations tested. Meanwhile, pathway analyses suggest the disruption of related and unique pathways, mostly connected with amino acid and energy metabolism. The pathways aminoacyl-tRNA biosynthesis, arginine biosynthesis, and glutathione metabolism were disrupted by most selected PAEs. Overall, this study indicates that although phthalate pollutants can elicit distinct metabolic perturbations to each PAE, they still impacted related biochemical pathways. These chemical-class based responses could be associated with a common toxic mechanism of action. The reported findings show how targeted metabolomic approaches can lead to a better understanding of sub-lethal exposure to pollutants, revealing metabolomic endpoints do not hold a close relationship with traditional acute toxicity endpoints.
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Contaminantes Ambientales , Ácidos Ftálicos , Contaminantes Químicos del Agua , Animales , Daphnia/metabolismo , Aminoácidos/metabolismo , Cromatografía Liquida , Contaminantes Químicos del Agua/toxicidad , Espectrometría de Masas en Tándem , Ácidos Ftálicos/toxicidad , Metabolismo Energético , Ésteres , Dibutil FtalatoRESUMEN
Synergism between different phases gives rise to chemical, biological or environmental reactivity, thus it is increasingly important to study samples intact. Here, SASSY (SimultAneous Solid and Solution spectroscopY) is introduced to simultaneously observe (and differentiate) all phases in multiphase samples using standard, solid-state NMR equipment. When monitoring processes, the traditional approach of studying solids and liquids sequentially, can lead to information in the non-observed phase being missed. SASSY solves this by observing the full range of materials, from crystalline solids, through gels, to pure liquids, at full sensitivity in every scan. Results are identical to running separate 13 C CP-MAS solid-state and 13 C solution-state experiments back-to-back but requires only a fraction of the spectrometer time. After its introduction, SASSY is applied to process monitoring and finally to detect all phases in a living freshwater shrimp. SASSY is simple to implement and thus should find application across all areas of research.
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Concerns regarding the persistence, bioaccumulation behaviour, and toxicity of perfluorooctanoic acid and perfluorooctane sulfonic acid have resulted in the creation of thousands of replacement perfluoroalkyl substances (PFAS). This study reports on the discovery of fluorotelomer ethoxylates (FTEO) in indoor dust (9/15 samples), and industrial effluents (14/37 samples) using gas chromatographic cyclic ion mobility mass spectrometry (GC-cIMS). By filtering the detected unknowns by mass and collision-cross section, a series of FTEO homologues were revealed with the formula F-(CF2)n(C2H4O)xH, where n = 6,8,10, and x = 4-12. The highest concentrations were observed in samples collected from healthcare facilities, consistent with the potential use of these compounds in anti-fog products, sprays used to prevent condensation on eyeglasses. FTEOs were also detected in c. 40 % of industrial effluent samples, with the highest concentrations in electroplating facilities, manufacturers of cosmetics and personal care products, and linen cleaning services for healthcare and work uniforms. These results suggest that FTEOs may well be widespread pollutants that are more persistent than previously thought, underlining the need for further study of their occurrence and potential impact to human health and the environment.
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Contaminantes Ambientales , Fluorocarburos , Humanos , Aguas Residuales , Polvo/análisis , Fluorocarburos/análisis , Contaminantes Ambientales/análisis , Cromatografía de Gases y Espectrometría de MasasRESUMEN
Forest ecosystems are important global soil carbon (C) reservoirs, but their capacity to sequester C is susceptible to climate change factors that alter the quantity and quality of C inputs. To better understand forest soil C responses to altered C inputs, we integrated three molecular composition published data sets of soil organic matter (SOM) and soil microbial communities for mineral soils after 20 years of detrital input and removal treatments in two deciduous forests: Bousson Forest (BF), Harvard Forest (HF), and a coniferous forest: H.J. Andrews Forest (HJA). Soil C turnover times were estimated from radiocarbon measurements and compared with the molecular-level data (based on nuclear magnetic resonance and specific analysis of plant- and microbial-derived compounds) to better understand how ecosystem properties control soil C biogeochemistry and dynamics. Doubled aboveground litter additions did not increase soil C for any of the forests studied likely due to long-term soil priming. The degree of SOM decomposition was higher for bacteria-dominated sites with higher nitrogen (N) availability while lower for the N-poor coniferous forest. Litter exclusions significantly decreased soil C, increased SOM decomposition state, and led to the adaptation of the microbial communities to changes in available substrates. Finally, although aboveground litter determined soil C dynamics and its molecular composition in the coniferous forest (HJA), belowground litter appeared to be more influential in broadleaf deciduous forests (BH and HF). This synthesis demonstrates that inherent ecosystem properties regulate how soil C dynamics change with litter manipulations at the molecular-level. Across the forests studied, 20 years of litter additions did not enhance soil C content, whereas litter reductions negatively impacted soil C concentrations. These results indicate that soil C biogeochemistry at these temperate forests is highly sensitive to changes in litter deposition, which are a product of environmental change drivers.
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Ecosistema , Suelo , Suelo/química , Bosques , Carbono , Nitrógeno , Cycadopsida , Microbiología del SueloRESUMEN
Per- and polyfluoroalkyl substances (PFAS) are a class of persistent organic pollutants used in industrial applications because of their physicochemical properties, which results in their ubiquitous presence across environmental matrices. To date, legacy PFAS have been well studied; however, the concentration of alternative PFAS may exceed the concentration of legacy pollutants, and more information is needed regarding the sublethal toxicity at the molecular level of aquatic model organisms, such as Daphnia magna. Perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorohexanesulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) are four widely detected PFAS alternatives of varying chain length and polar functionality that are quantified in aquatic environments. The present study examines the metabolic perturbations of PFAS with varying chemistries to D. magna using targeted mass spectrometry-based metabolomics. Daphnia were acutely exposed to sublethal concentrations of PFBA, PFHxA, PFHxS, and PFNA before the polar metabolite profile was extracted from single organisms. Multivariate analysis demonstrated significant separation between the sublethal concentrations of PFHxA, PFHxS, and PFNA relative to the controls; in sum, longer chain lengths demonstrated greater overall perturbations to the extracted metabolic profiles. Univariate statistics revealed significant perturbations in the concentrations of several amino acids, nucleotides/nucleosides, and neurotransmitters with exposure to PFAS. These metabolic perturbations are consistent with disruptions in energy metabolism (pantothenate and coenzyme A metabolism, histidine metabolism) and protein synthesis (aminoacyl-transfer RNA biosynthesis and amino acid metabolism), which were identified through biochemical pathway analysis. These results provide evidence that although PFAS chemistry (chain length and polar functional group) invokes unique metabolic responses, there is also an underlying toxic mode of action that is common with select PFAS exposure. Overall, the present study highlights the capabilities of environmental metabolomics to elucidate the molecular-level perturbations of pollutants within the same chemical class to model aquatic organisms, which can be used to prioritize risk assessment of substituted PFAS alternatives. Environ Toxicol Chem 2023;42:242-256. © 2022 SETAC.