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Metabolomics is the analysis of endogenous and exogenous low molecular mass metabolites within a cell, tissue, or biofluid of an organism in response to an external stressor. The sub-discipline of environmental metabolomics is the application of metabolomic techniques to analyze the interactions of organisms with their environment. There has been a rapid growth in environmental metabolomics over the past decade. This growth can be attributed to the comprehensive and rapid nature of nontargeted metabolomics and the ability to generate hypotheses involving complex environmental stressors, especially when the mode of action is unknown. Using a wide variety of model organisms, metabolomic studies have detected stress from abiotic factors such as xenobiotic exposure and temperature shifts as well as biotic stressors such as herbivory and competition. Nuclear magnetic resonance (NMR)-based metabolomics has been the dominant analytical platform used for environmental metabolomics studies, owing to its nonselectivity and ease of sample preparation. However, the number of mass spectrometry (MS)- based metabolomic studies is also increasing rapidly, owing to its high sensitivity for the detection of trace levels of metabolites. In this review, we provide an overview of the general experimental design, extraction methods, analytical instrumentation, and statistical methods used in environmental metabolomics. We then highlight some of the recent studies that have used metabolomics to elucidate hitherto unknown biochemical modes of actions of various environmental stressors to both terrestrial and aquatic organisms, as well as identify potential metabolite shifts as early bioindicators of these stressors. Through this, we emphasize the immense potential and versatility of environmental metabolomics as a routine tool for characterizing the responses of organisms to numerous types of environmental stressors. Key words: metabolic profiling, biomarkers, xenobiotics, mode of action, bioindicators. La metabolomique consiste a analyser les metabolites endogenes et exogenes de faibles poids moleculaires dans une cellule, un tissu ou un biofluide d'un organisme, en reaction a un agent stressant externe. La sous-discipline de la metabolomique environnementale porte sur l'application des techniques metabolomiques a l'analyse des interactions entre les organismes et leur environnement. On observe un developpement rapide de la metabolomique au cours de la derniere decade. On peut attribuer cet essor a la nature integrative et rapide de la metabolomique non ciblee et a sa capacite a generer des hypotheses impliquant des agents stressants complexes, surtout lorsque le mode d'action est inconnu. En utilisant une grande variete d'organismes modeles, les etudes metabolomiques ont decele des stress provenant de facteurs abiotiques tels que des expositions xenobiotiques ou des changements de temperature, aussi bien que des agents stressant biotiques comme l'herbivorie et la competition. La metabolomique basee sur la resonance magnetique nucleaire (RMN) constitue une plateforme analytique dominante utilisee pour les etudes en metabolomique environnementale, du a sa non-selectivite et a la preparation facile des echantillons. Cependant, on observe egalement une croissance rapide du nombre d'etudes metabolomiques basees sur la spectrographie de masse (SM) du a sa grande sensibilite pour la detection de metabolites a l'etat de traces. Dans leur revue, les auteurs presentent un survol des protocoles experimentaux generaux, des methodes d'extraction, de l'instrumentation analytique et des methodes statistiques utilises en metabolique experimentale. Ils soulignent certaines etudes recentes ayant utilise la metabolomique pour elucider les modes d'action de divers agents stressants environnementaux jusqu'ici inconnus, chez des organismes de milieux terrestres et aquatiques, ainsi que pour identifier le potentiel de glissements metaboliques comme indicateurs avances de ces agents stressants. Globalement, les auteurs mettent l'emphase sur l'immense potentiel et la versatilite de la metabolomique environnementale comme outil de routine pour caracteriser les reactions des organismes aux divers types d'agents stressants environnementaux. [Traduit par la Redaction] Mots-cles: profilage metabolique, marqueurs biologiques, xenobiotique, mode d'action, bio-indicateurs., Introduction Metabolomics (also known as metabonomics or metabolic profiling) is the field of science that characterizes endogenous and exogenous low molecular mass metabolites within a cell, tissue, or biofluid of [...]

This is the first comparative study to examine two different background monitoring sites in Japan to compare differences in the concentration and composition of long-range-transported polycyclic aromatic hydrocarbons (PAHs) from the Asian continent. This study chose the Noto Peninsula (the Kanazawa University Wajima Air Monitoring Station; WAMS) and Fukue Island (the Fukue-jima Atmosphere and Aerosol Monitoring Station; FAMS) to compare 10 weekly periods in 2009 and 2010 from autumn to spring, seasons that are strongly influenced by the Asian continent. The PAHs concentration differed significantly for most periods at these two sites. The backward trajectory analysis found that the low height of the air mass may cause the low concentration and the similar air mass condition could result in the similar concentration. The concentration of long-range-transported PAHs depended more on the source of the coal combustion areas such as Northeast China in heating period. [ABSTRACT FROM AUTHOR]

1H nuclear magnetic resonance (NMR)-based metabolomics was used to characterize the response of Daphnia magna after sub-lethal exposure to perfluorooctane sulfonate (PFOS), a commonly found environmental pollutant in freshwater ecosystems. Principal component analysis (PCA) scores plots showed significant separation in the exposed samples relative to the controls. Partial least squares (PLS) regression analysis revealed a strong linear correlation between the overall metabolic response and PFOS exposure concentration. More detailed analysis showed that the toxic mode of action is metabolite-specific with some metabolites exhibiting a non-monotonic response with higher PFOS exposure concentrations. Our study indicates that PFOS exposure disrupts various energy metabolism pathways and also enhances protein degradation. Overall, we identified several metabolites that are sensitive to PFOS exposure and may be used as bioindicators of D. magna health. In addition, this study also highlights the important utility of environmental metabolomic methods when attempting to elucidate acute and sub-lethal pollutant stressors on keystone organisms such as D. magna. [ABSTRACT FROM AUTHOR]

Highlights: [•] Daphnia magna responses to sub-lethal metal exposure using NMR-based metabolomics. [•] Copper and lithium had similar changes indicating a similar mode of action. [•] The changes suggest altered production of neurotransmitters and impaired energy metabolism. [•] Arsenic exposure shows changes in the amino acids lysine and alanine. [•] 1H NMR metabolomics provides insight into metal contamination on aquatic species. [Copyright &y& Elsevier]

Exposure to airborne particulates is estimated as the largest cause of premature human mortality worldwide and is of particular concern in sub-Saharan Africa where emissions are high and data are lacking. Particulate matter (PM) contains several toxic organic species including polycyclic aromatic hydrocarbons (PAHs) and nitrated PAHs (NPAHs). This study provides the first characterization and source identification for PM 10 - and PM 2.5 -bound PAHs and NPAHs in sub-Saharan Africa during a three-month period that spanned dry and wet seasons at three locations in Rwanda. The 24-h mean PM 2.5 and PM 10 concentrations were significantly higher in the dry than the wet season. PAH and NPAH concentrations at the urban roadside site were significantly higher than the urban background and rural site. Source identification using diagnostic ratio analysis and principal component analysis (PCA) revealed diesel and gasoline-powered vehicles at the urban location and wood burning at the rural location as the major sources of PAHs and NPAHs. Our analysis demonstrates that PM concentrations and lifetime cancer risks resulting from inhalation exposure to PM-bound PAHs and NPAHs exceed World Health Organization safe limits. This study provides clear evidence that an immediate development of emission control measures is required.

¹H nuclear magnetic resonance (NMR)-based metabolomics was used to characterize the response of Daphnia magna after sub-lethal exposure to perfluorooctane sulfonate (PFOS), a commonly found environmental pollutant in freshwater ecosystems. Principal component analysis (PCA) scores plots showed significant separation in the exposed samples relative to the controls. Partial least squares (PLS) regression analysis revealed a strong linear correlation between the overall metabolic response and PFOS exposure concentration. More detailed analysis showed that the toxic mode of action is metabolite-specific with some metabolites exhibiting a non-monotonic response with higher PFOS exposure concentrations. Our study indicates that PFOS exposure disrupts various energy metabolism pathways and also enhances protein degradation. Overall, we identified several metabolites that are sensitive to PFOS exposure and may be used as bioindicators of D. magna health. In addition, this study also highlights the important utility of environmental metabolomic methods when attempting to elucidate acute and sub-lethal pollutant stressors on keystone organisms such as D. magna .