Category Archives: Methods & Applications

Posts describing the use of the nmr spectroscopy (MRS) methodology, either from a practical point of view (how to perform certain experiment), or from a more theoretical perspective (description of techniques and their application).

On the interference of JHH modulation in HSQMBC-IPAP and HMBC-IPAP experiments

cover_MRC“On the interference of J(HH) modulation in HSQMBC-IPAP and HMBC-IPAP experiments”, by Josep Saurí and Teodor ParellaMagn. Reson. Chem. 2013. DOI: 10.1002/mrc.3977

The effects of phase signal modulation due to homonuclear proton–proton coupling constants in HSQMBC-IPAP and HMBC-IPAP experiments are experimentally evaluated. An assessment of the reliability ofnJCH measurement from distorted cross-peaks obtained in IPAP versions of HMBC and HSQMBC experiments is presented. Continue reading On the interference of JHH modulation in HSQMBC-IPAP and HMBC-IPAP experiments

CLIP-HSQMBC: Very easy, direct and accurate measurement of nJCH in organic molecules and natural products

CLIP-HSQMBC: Easy measurement of small proton-carbon coupling constants in organic molecules, by Josep Saurí, Teodor Parella and Juan F. Espinosa; Org. Biomol. Chem., 2013, 11, 4473-4478. DOI:10.1039/C3OB40675J

A user-friendly 2D NMR approach denoted as CLIP-HSQMBC is proposed for the very easy, direct and accurate measurement of long-range proton-carbon coupling constants in organic molecules and natural products. The J value can be extracted directly from the analysis of resolved in-phase 1H multiplets that show an additional splitting arising from the proton-carbon coupling. Continue reading CLIP-HSQMBC: Very easy, direct and accurate measurement of nJCH in organic molecules and natural products

J-selHSQMBC: Simultaneous measurement of JHH and two different nJCH using IPAP, J-resolved and E.COSY principles

cover_MRC“Simultaneous measurement of J(HH) and two different nJ(CH) coupling constants from a single multiply-edited 2D cross-peak”, by Josep Saurí and Teodor ParellaMagn. Reson. Chem. 201351, 397-402. DOI: 10.1002/mrc.3960

Three different J-editing methods (IPAP, E.COSY and J-resolved) are implemented in a single NMR experiment to provide spin-state-edited 2D cross-peaks from which simultaneous measurement of different homonuclear and heteronuclear coupling constants can be performed. Continue reading J-selHSQMBC: Simultaneous measurement of JHH and two different nJCH using IPAP, J-resolved and E.COSY principles

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

Brain magnetic resonance in liver failure

“Brain magnetic resonance in experimental acute-on-chronic liver failure” by L. Chavarria, M. Oria, J. Romero-Giménez, J. Alonso, S. Lope-Piedrafita, and J. Cordoba.
Liver International 33 (2013) 294-300. DOI: 10.1111/liv.12032

Liver failure causes brain edema that can lead to intracranial hypertension and death. It is currently uncertain whether this water accumulation is predominantly intracellular or extracellular, something important to determine in order to apply the most adequate therapeutic measures. The aim of this study was to investigate the mechanisms involved in the neurological manifestations occurring in an experimental acute-on-chronic liver failure rat model that combines sustained liver injury with a factor inducing an inflammatory response.

Continue reading Brain magnetic resonance in liver failure

Cardiac MRI of the Sirt1-deficient mouse heart

“Dilated cardiomyopathy and mitochondrial dysfunction in Sirt1-deficient mice: A role for Sirt1-Mef2 in adult heart”
by A. Planavila, E. Dominguez, M. Navarro, M. Vinciguerra, R. Iglesias, M. Giralt, S. Lope-Piedrafita, J. Ruberte, F. Villarroya. Journal of Molecular and Cellular Cardiology 53 (2012) 521-531. DOI: 10.1016/j.yjmcc.2012.07.019

The protein deacetylase Sirtuin-1 (Sirt1) is involved in the cardiac hypertrophic responses and cardiac embryo morphogenesis. However, the physiological function of Sirt1 deficiency in the postnatal development of the heart remains to be characterized. The aim of this study was to investigate the relevance of Sirt1 in the development and function of the myocardium by using complementary techniques, such as gene expression, immunoblotting, immunohistochemistry, histological and electron microscopy examinations, and in vivo cardiac magnetic resonance imaging (MRI).

Continue reading Cardiac MRI of the Sirt1-deficient mouse heart

P.E.HSQMBC: Simultaneous measurement of proton–proton and proton–carbon coupling constants

“P.E.HSQMBC: Simultaneous measurement of proton–proton and proton–carbon coupling constants” by Josep Saurí, Pau Nolis, Laura Castañar, Albert Virgili and Teodor Parella. Journal of Magnetic Resonance 224 (2012) 101–106. DOI: 10.1016/j.jmr.2012.09.007

A long-range optimized P.E.HSQC experiment, named P.E.HSQMBC, is proposed for the simultaneous measurement of a complete set of homonuclear and heteronuclear coupling constants from a single 2D cross-peak. Continue reading P.E.HSQMBC: Simultaneous measurement of proton–proton and proton–carbon coupling constants

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

HSQMBC-COSY: Measurement of the sign and the magnitude of long-range proton-carbon coupling constants

“Efficient measurement of the sign and the magnitude of long-range proton-carbon coupling constants from a spin-state-selective HSQMBC-COSY experiment”, by Josep Saurí and Teodor Parella; Magn. Reson. Chem. 2012, 50, 717-721. DOI:10.1002/mrc.3867

A spin-state-selective HSQMBC-COSY experiment is proposed to measure the sign and  the magnitude of long-range proton-carbon coupling constants (nJ(CH); n>1) either for protonated and for non-protonated carbons in small molecules. Continue reading HSQMBC-COSY: Measurement of the sign and the magnitude of long-range proton-carbon coupling constants

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.