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. In addition, the enantioresolution quotient, E, is proposed as the parameter to describe its quantification. Complementary to ΔΔδ, the experimental determination of E allows a more reliable interpretation of the results and opens up new possibilities for the study of enantiodifferentiation data derived from novel NMR experiments, setup improvements or new CAs.

Review: Recent Advances in Small Molecule NMR: Improved HSQC and HSQMBC Experiments

annrep“Recent Advances in Small Molecule NMR: Improved HSQC and HSQMBC Experiments” by Laura Castañar and Teodor Parella. Annual Reports on NMR Spectroscopy, 2015, 84, 163–232.

DOI: 10.1016/bs.arnmr.2014.10.004
a

A general description of the latest developments in heteronuclear single-quantum correlation and heteronuclear single-quantum multiple bond correlation experiments designed for small molecules at the natural isotopic abundance is reported. A discussion is made on the details introduced into novel NMR pulse sequences with special emphasis on modern concepts such as fast NMR or pure shift NMR and also on robust techniques affording pure in-phase multiplet patterns, which are amenable for a simpler and a more accurate analysis. The suitability of some of these methods for the quantitative measurement of one-bond and long-range proton–carbon coupling values in molecules in isotropic and weakly aligned anisotropic conditions is also reviewed.

 

in vivo MRS and ex vivo HRMAS in an Ischemic Rat Stroke Model

JCBMcover“In vivo and ex vivo Magnetic Resonance Spectroscopy of the Infarct and the Subventricular Zone in Experimental Stroke” by E. Jiménez-Xarrié, M. Davila, S. Gil-Perotín, A. Jurado-Rodríguez, A.P. Candiota, R. Delgado-Mederos, S. Lope-Piedrafita, J.M. García-Verdugo, C. Arús, J. Martí-Fàbregas. Journal of Cerebral Blood Flow & Metabolism (2015), 1–7. DOI: 10.1038/jcbfm.2014.257

Ischemic stroke changes the metabolic pattern in the infarct area and also in other regions such as the ipsilateral subventricular zone (SVZi) where neural progenitor cells (NPCs) proliferation is enhanced in the mammalian and human brains. Magnetic resonance spectroscopy (MRS) provides metabolic information in vivo. With regard to NPCs proliferation, a resonance at 1.28 ppm has been described as an in vivo MRS biomarker of NPCs in the hippocampus of rats and humans. However, many authors disagree with this interpretation as this resonance has been found in different cell types and during different developmental stages corresponding to mobile lipids (MLs). High-resolution magic-angle spinning (HRMAS) also provides metabolic information, and moreover, with higher sensitivity and spectral resolution than MRS, however, it is used ex vivo and postmortem metabolic changes could affect the final metabolic pattern. Therefore, in this study, in vivo MRS and ex vivo HRMAS were used as complementary techniques to better characterize the metabolic pattern of the infarct and the NPCs in the ipsilateral subventricular zone.

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A New Polarizing Agent for Dissolution-DNP

OBC_CoverIssue

“A Benzyl Alcohol Derivative of BDPA Radical for Fast Dissolution Dynamic Nuclear Polarization NMR Spectroscopy” by José Luis Muñoz Gómez, Eva Monteagudo, Vega Lloveras, Teodor Parella, Jaume Veciana and José Vidal Gancedo. Org. Biomol. Chem., 2015.

DOI: 10.1039/C4OB02356K

 

The synthesis, structural characterization and the successful application of a carbon centered radical derived from 1,3-bisdiphenylene-2-phenylallyl (BDPA), its benzyl alcohol derivative (BA-BDPA), as a polarizing agent for Dynamic Nuclear Polarization (DNP) are described. The reported BA-BDPA radical meets all the requirements to become a promising candidate for its use in in-vivo DNP-NMR experiments: it is soluble into neat [1-13C]pyruvic acid, insoluble in the dissolution transfer solvent and effective as a polarizing agent in fast dissolution DNP-NMR applications, without the need of using glassing agents. Moreover, it enables a simple but effective in-line radical filtration to obtain hyperpolarized solutions of [1-13C]pyruvic acid free of radicals, that offer a much better polarization performance.

Figura_blog_BA_BDPA

 

 

Ultra high-resolution HSQC: Application to the efficient and accurate measurement of heteronuclear coupling constants

Journal cover: Chemical Communications“Ultra high-resolution HSQC: Application to the efficient and accurate measurement of heteronuclear coupling constants” by Núria Marcó,  Andre Fredi and Teodor Parella Chemical Communications (2015)

DOI: 10.1039/C4CC10279G

A rapid NMR data acquisition strategy in terms of enhanced resolution per time unit for the simple and efficient determination of multiple coupling constants is described. The use of 13C spectral aliasing combined with broadband 1H homodecoupling allows accurate measurements from ultra high resolved 2D HSQC cross-peaks.imagen4

 

Pulse Program Code for Bruker:

SAPS-HSQC*

Data set Example:

Fluoropyridine

 

*Ref: “Simultaneous 1H and 13C NMR enantiodifferentation from highly-resolved pure shift HSQC spectra”

ANALYSIS OF SPHINGOLIPIDS AGGREGATES BY NMR

SeRMN seminar

  • Date: Thursday 22th January, 2015
  • Hour: 12 am
  • Location:  SeRMN,  Facultats de Ciències i Biociències, C2/-135
  • Speaker:  André Fredi, SeRMN PhD Student

 

The sphingosine and sphingosine-1-phosphate are sphingolipids with important functions in different organisms. The amphipathic nature of these molecules favor the formation of micelles in aqueous medium, but there are few studies on the aggregation process. Thus, this study aimed to evaluate the aggregation behavior of these two substances by means of NMR analysis in different experimental conditions.

Imagen1

Master dissertation

ANALYSIS OF SPHINGOLIPIDS AGGREGATES BY NMR

9th Workshop on Magnetic Resonance Spectroscopy and Imaging (MRI/MRS) Applied to Laboratory Animals

Dates: February 3rd to 6th, 2015

Organized by the SeRMN of the Autonomous University of Barcelona (UAB).

This course cMRIombines a comprehensive series of lectures on the technology of Magnetic resonance spectroscopy and imaging (MRS/MRI) with hands-on laboratory sessions to provide practical demonstrations of key concepts and procedures for preclinical studies.

Whether you are considering MRI as a research tool in your lab or just would like to learn more about MRI, this workshop addresses practical aspects of experimental MRI with laboratory animals and provide valuable hands-on experience on a 7 Tesla Bruker BioSpec spectrometer.

Number of participants will be limited to 4.

For the registration, please fill the Registration Form and email it to silvia.lope@uab.es (registration deadline ends January 19th)

See the workshop brochure for more information or contact Dra. Silvia Lope via email.

TRANSACT-ITN Scientific Workshop on “Spectra Classification and Decision-Support tools in the clinic”

Workshop on “Spectra Classification and Decision-Support tools in the clinic”
December 3-4, 2014 
Universitat Autònoma Barcelona, Spain

The TRANSACT European Project organizes a two-days scientific workshop on “Spectra Classification and Decision-Support tools in the clinic”. The workshop will be held on December 3-4, 2014 at Hotel Campus UAB which is located in the campus of Universitat Autònoma de Barcelona.

The purpose of this workshop is to introduce attendants to:

  • Pattern recognition methods for the analysis of magnetic resonance spectroscopy data.
  • Implementing classifiers based on magnetic resonance spectroscopy data into decision-support systems.
  • Design principles for successful decision-support systems.
  • Integrating evidence-based clinical decision-making into decision-support systems.

Workshop faculty: Prof. Sabine van Huffel, ESAT KU Leuven, Belgium. Dr. Diana Sima, ESAT KU Leuven, Belgium. Prof. Paulo Lisboa, Liverpool John Moores University, United Kingdom. Dr. Alfredo Vellido, Universitat Politècnica de Catalunya, Spain. Mr. Joshua Underwood, London Knowledge Lab, Institute of Education, London. Dr. Juan Miguel García-Gómez, IBIME, Universidad Politécnica de Valencia, Spain. Dr. Dionisio Acosta-Mena, University College London, United Kingdom.

Local organizers: Margarida Julià-Sapé, CIBER-BBN. Miquel Cabañas, SeRMN, UAB. Carles Arús, GABRMN, Department of Biochemistry and Molecular Biology, UAB.

Registration Fees: Attendance to the workshop requires previous on-line registration and has a registration fee of 50 € for TRANSACT-ITN non-members. Registration Fees include: workshop registration and materials, tea/coffee-breaks and lunches.

The full announcement can be found at  http://gabrmn.uab.es/transact_workshop

Banner of Transact workshop on Spectra Classification and Decision-Suport Tools in the Clinic

Lilly Research Award to Laura Castañar

Laura Castañar is top finalist to the Lilly XII Research Awards for Graduate Students. The prize is awarded to ten Spanish young scientists, three awardees and seven finalists, for their research contributions in the field of chemistry. The awards ceremony took place at Lilly Research & Development Centre in Alcobendas, Madrid, Spain, the 26th September, 2014.

Laura Castañar and Lilly representatives at Lilly XII Research Awards for Graduate Students. Laura is the first person on the left.
Laura Castañar and Lilly representatives at Lilly XII Research Awards for Graduate Students. Laura is the first person on the left.

The prize by the Lilly European Academic Contacts Committee (EUACC) is awarded for innovative research in the areas of organic chemistry, analytical chemistry and pharmacy, and it aims at fostering research and collaboration between Lilly Research Laboratories and the academic chemistry community.

Lilly XII Research Awards for Graduate Students
Finalists of the Lilly XII Research Awards for Graduate Students. Laura is the first person on the right.

Laura has been working as a Ph.D. candidate at the Department of Chemistry and SeRMN under the co-direction of Dr. Albert Virgili and Dr. Teodor Parella since Sept 2012, when she enrolled in the Department of Chemistry doctoral program at Universitat Autònoma de Barcelona with a fellowship from UAB. She is currently in her third year and expects to defend the doctoral thesis on 2015. You can read about her work on this blog.

Hyperpolarized 13C Magnetic Resonance in Acute Liver Failure Rats

2014_coverNMinBiomedReal-time assessment of 13C metabolism  reveals an early lactate increase in the brain of rats with acute liver failure” by Laia Chavarria, Jordi Romero-Giménez, Eva Monteagudo, Silvia Lope-Piedrafita, Juan Cordoba. NMR in Biomedicine 2014. DOI: 10.1002/nbm.3226

Intracranial hypertension is a severe complication of acute liver failure (ALF) secondary to brain edema. The pathogenesis of cerebral edema in ALF is not clear, but seems to be related to energy metabolism in which lactate may have an important role. The aim of this study was to follow the synthesis of brain lactate using a novel in vivo metabolic technology in a rat model of ALF. Time-resolved 13C MRS of hyperpolarized 13C1-pyruvate was used to quantitatively follow the in vivo conversion of pyruvate to its substrates in a model of devascularized ALF in rats. Rats with ALF showed a significant increase in the lactate to pyruvate ratio from 36% to 69% during the progression of liver disease relative to rats with portocaval anastomosis. Rats with ALF also showed a significant increase in the alanine to pyruvate ratio from 72% to 95%. More interestingly, these increases were detectable at very early stages, just 6 h after ALF when animals had no evident disease signs in their behavior (without loss of righting or corneal reflexes). This study shows the dynamic consequences of cerebral in vivo 13C metabolism at real time in rats with ALF. The early detection of the de novo synthesis of lactate suggests that brain lactate is involved in the physiopathology of ALF.

HyperpolarizationALFrats