All posts by Miriam

NMR-Aided Differentiation of Enantiomers: Signal Enantioresolution

15ACA“NMR-Aided Differentiation of Enantiomers: Signal Enantioresolution” by Míriam Pérez-Trujillo, Teodor Parella and Lars T. Kuhn. Analytica Chimica Acta, 2015. DOI: 10.1016/j.aca.2015.02.069

NMR-aided enantiodiscrimination using chiral auxiliaries (CAs) is a recognized method for differentiating enantiomers and for measuring enantiomeric ratios (er). Up to the present, the study, optimization, and comparison of such methods have been performed based on the enantiodifferentiation of NMR signals via analysing non-equivalent chemical-shift values (ΔΔδ) of the diastereoisomeric species formed. However, a poor and non-reliable comparison of results is often obtained via the analysis of ΔΔδ exclusively. In here, the concept of enantioresolution of an individual NMR signal and its importance for NMR-aided enantiodifferentiation studies is introduced and discussed. Continue reading NMR-Aided Differentiation of Enantiomers: Signal Enantioresolution

Diversity of pyrrolizidine alkaloids in native and invasive Senecio pterophorus (Asteraceae): Implications for toxicity

14Phytochemistry“Diversity of pyrrolizidine alkaloids in native and invasive Senecio pterophorus (Asteraceae): Implications for toxicity” by Eva Castells, Patrick P.J. Mulder  and Miriam Perez-Trujillo. Phytochemistry (2014) 108:137-146. DOI: 10.1016/j.phytochem.2014.09.006

Changes in plant chemical defenses after invasion could have consequences on the invaded ecosystems by modifying the interactions between plants and herbivores and facilitating invasion success. However, no comprehensive biogeographical studies have yet determined the phenotypic levels of plant chemical defenses, as consumed by local herbivores, covering large distributional areas of a species. Continue reading Diversity of pyrrolizidine alkaloids in native and invasive Senecio pterophorus (Asteraceae): Implications for toxicity

Simultaneous 1H and 13C NMR enantiodifferentiation from highly-resolved pure shift HSQC spectra

CoverIssue“Simultaneous 1H and 13C NMR enantiodifferentiation from highly-resolved pure shift HSQC spectra” by Miriam Pérez-Trujillo, Laura Castañar, Eva Monteagudo, Lars T. Kuhn, Pau Nolis, Albert Virgili, R. Thomas Williamson and Teodor Parella. Chemical Communications  50:10214-10217 (2014). DOI: 10.1039/C4CC04077E

NMR-aided discrimination of enantiomers using chiral solvating agents (CSAs) is a well established method of enantiodifferentiation and measurement of enantiomeric ratios (er). The analysis is traditionally performed by observing chemical shift differences (ΔΔδ) in 1H signals by conventional 1D 1H NMR spectra. However, low ΔΔδ values and signal overlap caused by complex multiplets lead to the lack of spectral signal dispersion that preclude a straightforward analysis. Continue reading Simultaneous 1H and 13C NMR enantiodifferentiation from highly-resolved pure shift HSQC spectra

Enantiodifferentiation through 13C NMR Spectroscopy and CSAs

 13ac10887(85)13C NMR spectroscopy for the differentiation of enantiomers using chiral solvating agents” Míriam Pérez-Trujillo, Eva Monteagudo and Teodor Parella. Analytical Chemistry, 2013, 85 (22), pp 10887–10894. DOI: 10.1021/ac402580j

The utility of 13C NMR spectroscopy for the differentiation of enantiomers using chiral solvating agents (CSA) is stated. Three examples involving the enantiodifferentiation of a drug, a metabolite and a reactant in aqueous and organic solutions have been chosen to show it. Continue reading Enantiodifferentiation through 13C NMR Spectroscopy and CSAs

Presentations at the SMASH NMR Conference 2013

Next week several SeRMN members will present our research work at the SMASH NMR Conference 2013 that will take place in Santiago de Compostela (Spain) from 22nd to 25th September. Find below a summary of our contributions.SMASH-2 Continue reading Presentations at the SMASH NMR Conference 2013

NMR-based Protocol for Ecometabolomics

13MEE“Ecometabolomics: Optimized NMR-based method” by Albert Rivas-Ubach, Miriam Pérez-Trujillo, Jordi Sardans, Albert Gargallo-Garriga, Teodor Parella, Josep Peñuelas. Methods in Ecology and Evolution, February 2013. DOI: 10.1111/2041-210X.12028

Metabolomics is allowing great advances in biological sciences and in particular Ecometabolomics (metabolomic approach for ecological studies). Ecometabolomics is a powerful tool that allows identifying changes in the metabolome of individuals of the same species associated to environmental changes, detecting and identifying biological markers. Continue reading NMR-based Protocol for Ecometabolomics

Tuberculosis mycobacterium and microscopic cords formation. Related to their virulence

“Cyclopropanation of α-mycolic acids is not required for cording in non-tuberculous mycobacteria” Cecilia Brambilla, Alejandro Sánchez-Chardi, Míriam Pérez-Trujillo, Esther Julián, Marina Luquin.  Microbiology, March 2012. DOI: 10.1099/mic.0.057919-0

Mycobacterium tuberculosis and Mycobacterium bovis are the principal agents responsible for human tuberculosis and tuberculosis in domestic and wild animals. Both form microscopic cords, a phenotypic characteristic that has been related to their virulence. The compounds responsible for cording are unknown, but a recent work has shown that cording could be related to the fine structure of α-mycolic acids. Continue reading Tuberculosis mycobacterium and microscopic cords formation. Related to their virulence

Metabolic profiling for the detection of early effects of environmental and lifestyle exposure to cadmium.

“Metabolic Profiling Detects Early Effects of Environmental and Lifestyle Exposure to Cadmium in a Human Population” JK Ellis, TJ Athersuch, LDK Thomas, F Teichert, M Pérez-Trujillo, C Svendsen, D J. Spurgeon, R Singh, L Järup, JG Bundy and HC Keun.  BMC Medicine, February 2012.  DOI: 10.1186/1741-7015-10-61

The ‘exposome’ represents the accumulation of all environmental exposures across a lifetime. Top-down strategies are required to assess something this comprehensive, and could transform our understanding of how environmental factors affect human health. Metabolic profiling (metabonomics / metabolomics)  defines an individual’s metabolic phenotype, which is influenced by genotype, diet, lifestyle, health and xenobiotic exposure, and could also reveal intermediate biomarkers for disease risk that reflect adaptive response to exposure. Continue reading Metabolic profiling for the detection of early effects of environmental and lifestyle exposure to cadmium.

Presentations to the Ibero-American NMR & GERMN Bienal & Iberian NMR joint meeting

Next week several SeRMN members will present our research work at the IV Ibero-American NMR – VI GERMN Bienal – III Iberian NMR joint meeting that will take place in Aveiro (Portugal) from 25th to 28th September. Find below a summary of our contributions.

Continue reading Presentations to the Ibero-American NMR & GERMN Bienal & Iberian NMR joint meeting