Comparison between 5 extractions methods in either plasma or serum to determine the optimal extraction and matrix combination for human metabolomics

Abstract Background Although metabolomics continues to expand in many domains of research, methodological issues such as sample type, extraction and analytical protocols have not been standardized, impeding proper comparison between studies and future research. Methods In the present study, five solvent-based and solid-phase extraction methods were investigated in both plasma and serum. All these extracts were analyzed using four liquid chromatography coupled with high resolution mass spectrometry (LC–MS) protocols, either in reversed or normal-phase and with both types of ionization. The performances of each method were compared according to putative metabolite coverage, method repeatability and also extraction parameters such as overlap, linearity and matrix effect; in both untargeted (global) and targeted approaches using fifty standard spiked analytes. Results Our results verified the broad specificity and outstanding accuracy of solvent precipitation, namely methanol and methanol/acetonitrile. We also reveal high orthogonality between methanol-based methods and SPE, providing the possibility of increased metabolome coverage, however we highlight that such potential benefits must be weighed against time constrains, sample consumption and the risk of low reproducibility of SPE method. Furthermore, we highlighted the careful consideration about matrix choice. Plasma showed the most suitable in this metabolomics approach combined with methanol-based methods. Conclusions Our work proposes to facilitate rational design of protocols towards standardization of these approaches to improve the impact of metabolomics research

Occurrence of carbamazepine, diclofenac, and their related metabolites and transformation products in a French aquatic environment and preliminary risk assessment

International audienceWith questions emerging on the presence and risks associated with metabolites and transformation products (TPs) of organic contaminants in the aquatic environment, progress has been made in terms of monitoring and regulation of pesticide metabolites. However, less interest is shown for pharmaceutical residues, although their pseudo-persistence and adverse effects on non-target organisms are proven. This study provides original knowledge about th

Integrative analytical workflow to enhance comprehensive analysis of organic molecules in extraterrestrial objects

International audienceMolecular identification is a fundamental issue in astrobiology to investigate the routes of emergence of life on our planet involving in particular a potential seeding of extraterrestrial organic matter on the primitive Earth. However, this project encompasses major difficulties due to the low concentration of molecules present in bodies of the Solar System. This work proposes an integrative analytical workflow, no longer based on GC-MS instruments, to enhance comprehensive analysis of organic markers in these objects. Our strategy combines UPLC-HRMS and UPLC-MRM MS methods to bring both a broad molecular mapping and detailed data on indigenous compounds present in any extraterrestrial objects or laboratory analogs. Applied on water extracts from fresh meteorites, our workflow highlights a wide range of free molecules in the non-treated extracts and reveals the wide diversity of amino acid and nucleobase isomers that could lead to misinterpretation as far as the molecular composition of meteorite extracts cannot be anticipated. This strategy, never explored so far, would provide new clues for studying the organic matter in space and should offer new perspectives on its evolution and reactivity

Phosphine-Mediated Bioconjugation of the 3′-End of RNA

International audienceStaudinger ligation is an attractive bio-orthogonal reaction that has been widely used to tag proteins, carbohydrates, and nucleic acids. Here, we explore the traceless variant of the Staudinger ligation for 3′-end modification of oligoribonucleotides. An azido-containing dinucleotide was used to study the ligation. Nine phosphines containing reactive groups, affinity purification tags, or photoswitch probes have been successfully obtained. The corresponding modified dinucleotides were synthesized and characterized by LC/MS. Mechanistic interpretations of the reaction are proposed, in particular, the unprecedented formation of an oxazaphospholane nucleotide derivative, which was favored by the vicinal position of 2′-N3 and 3′-OH functional groups on the terminal ribose has been observed. The post-functionalization of a 24-nt RNA with a photoactivable tag is also reported

Assessing the effect of aqueous alteration on soluble organic matter in primitive carbonaceous chondrites: the case of Asuka 12236

Carbonaceous chondrites (CC) are considered the closest solid material to the composition of the early Solar System and can provide information on the origin of organic matter (OM) in the system and on Earth. Despite being primitive, their parent bodies have undergone secondary processes shortly after their formation (hydrothermal or metamorphism alterations) that blur their initial organic or mineral composition. The most primitive CC members are hence very precious to study the original composition. Here, we report the characterisation of the soluble organic matter (SOM) of Asuka 12236 classified among the most primitive members of the CM group in comparison with the SOM from other CM chondrites: Paris, Murchison and Aguas Zarcas. Analysis of these SOM were performed using several analytical techniques including elemental analysis, high resolution mass spectrometry and liquid chromatography coupled to different mass spectrometers. Our results show that Asuka 12236 has the lowest H content among the CMs studied here, and presents heterogeneity in its C content, likely indicating variable degrees of aqueous alteration. High resolution mass spectrometry analysis reveals that Asuka 12236 has a molecular diversity similar to the SOM of Murchison and Aguas Zarcas but with higher abundance of sulfur compounds more similar to Paris SOM. The content of organomagnesiumcompounds indicates no high pressure or temperature stress but rather mid-temperature aqueous alteration for Asuka 12236, like Murchison SOM, but unlike Paris or Aguas Zarcas SOM. From liquid chromatography coupled with mass spectrometry analysis, we observed the highest concentration of amino acids in Asuka 12236 compared to the other CM chondrites considered here. Amino acids are mainly of alpha forms, witnessing of a Strecker formation or a formose-type reaction under low amounts of water, in agreement with the low H content recorded in this peculiar chondrite. This study of the SOM of chondrites with different alteration degrees highlights that organic compounds may be transformed much more rapidly than the minerals during hydrothermal alteration. This OM evolution depends on the amount of water and/or the temperature and/or pressure, leading towards significant transformation from one chondrite to another while the mineralogy can indicate a low degree of alteration. In addition to better assess the initial OM in chondrites, the impact of aqueous alteration on organic matter calls for additional laboratory experimentation

A β-Cyclodextrin-Albumin Conjugate for Enhancing Therapeutic Efficacy of Cytotoxic Drugs

International audienc

Evidence for Proteogenic Peptide-like Sequences in Meteorites Through an Enzyme-Catalysed Stereoselective Hydrolysis Strategy

In this manuscript, we evidenced for the first time proteogenic like peptide sequences in meteorite thanks to an original stereoselective enzymatic hydrolysis. Within this framework, we have first characterised the amino acids content of two meteorites, Murchison and Allende, after the standard acid hydrolysis protocol currently used in astronomical studies. To reach this goal, we have developed a highly sensitive chiral LC-MS method and we have highlighted new l- and d-enantiomers, never detected before in both meteorites. These primary findings extend the list of amino acids already found in meteorites. We next investigated the presence of proteogenic like peptide sequences. For that, we have compared the amounts of amino acids l- and d-enantiomers released from either the standard acid hydrolysis or our stereoselective peptidase hydrolysis. Thanks to this strategy, we have highlighted the presence of peptide sequences involving proteogenic l-amino acids in the Murchison together with their absence in Allende, which is consistent with the respective organic content of both meteorites. Furthermore, we demonstrated that the peptide sequences were indigenous to the Murchison meteorite.<br /

Assessing the Effect of Aqueous Alteration on Soluble Organic Matter in Primitive Carbonaceous Chondrites: The Case of Asuka 12236

Carbonaceous chondrites (CCs) are considered the closest solid material to the composition of the early Solar System and can provide information about the origin of organic matter (OM) in the system and on Earth. Despite being primitive, their parent bodies have undergone secondary processes shortly after their formation (hydrothermal or metamorphism alterations) that blur their initial organic or mineral composition. The most primitive CC members are hence very precious to study the original composition. Here, we report the characterization of the soluble organic matter (SOM) of Asuka 12236, classified among the most primitive members of the CM group in comparison with the SOM from other CM chondrites: Paris, Murchison, and Aguas Zarcas. Analysis of these SOM were performed using several analytical techniques, including elemental analysis, high-resolution mass spectrometry, and liquid chromatography coupled to different mass spectrometers. Our results show that Asuka 12236 has the lowest H content among the CMs studied here and presents heterogeneity in its C content, likely indicating variable degrees of aqueous alteration. High-resolution mass spectrometry analysis reveals that Asuka 12236 has a molecular diversity similar to the SOM of Murchison and Aguas Zarcas but with a higher abundance of sulfur compounds, more similar to Paris SOM. The content of organomagnesium compounds indicates no high-pressure or -temperature stress but rather mid-temperature aqueous alteration for Asuka 12236, like Murchison SOM, but unlike Paris or Aguas Zarcas SOM. From liquid chromatography coupled with mass spectrometry analysis, we observed the highest concentration of amino acids in Asuka 12236 compared to the other CM chondrites considered here. Amino acids are mainly of α forms, witnessing a Strecker formation or a formose-type reaction under low amounts of water, in agreement with the low H content recorded in this peculiar chondrite. This study of the SOM of chondrites with different degrees of alteration highlights that organic compounds may be transformed much more rapidly than the minerals during hydrothermal alteration. This OM evolution depends on the amount of water and/or the temperature and/or pressure, leading toward significant transformation from one chondrite to another, while the mineralogy can indicate a low degree of alteration. In addition, to better assess the initial OM in chondrites, the impact of aqueous alteration on organic matter calls for additional laboratory experimentation