“Preclinical MRI: Methods and Protocols” by Maria Luisa Garcia Martin and Pilar Lopez Larrubia (Editors). Part of the Methods in Molecular Biology book series (MIMB, volume 1718). DOI: 10.1007/978-1-4939-7531-0.
This book was conceived with the idea of providing an update on a wide variety of preclinical MRI methods and protocols to help technicians and researchers interested in this technology. The basics of MRI physics are introduced, followed by chapters describing updated methodology and protocols for some standard and more advanced MRI techniques covering diffusion, perfusion, functional imaging, in-vivo spectroscopy (proton and heteronuclear), susceptibility contrast MRI… The book also contains some chapters where some applications of those methods are illustrated in animal models of several diseases including cancer, stroke and neurodegeneration. Protocols are described in a step-by-step approach, with interesting notes and tips at the end of each chapter, which -a priori- should allow the new worker to obtain successful results with the first attempt ;o) .
As is tradition in Catalonia in February, the group of SeRMN got together to enjoy a Calçotada, eating the typical Calçots (a type of scallion or green onion) well combined with a “Porró” (is a traditional glass wine pitcher).
“Isotropic/Anisotropic NMR Editing by Resolution-Enhanced NMR Spectroscopy” by Núria Marcó, R. R. Gil and Teodor Parella. ChemPhysChem 2018,
Modern resolution-enhanced NMR techniques can monitor the in-situ discrimination of co-existing isotropic and anisotropic contributions of small molecules dissolved in weakly aligning PMMA/CDCl3 media. The simultaneous sign-sensitive determination of accurate Δδ(1H) and Δδ(13C) between isotropic and anisotropic signals, and/or 1TCH and 1JCH coupling constants (and consequently 1H-13C RDCs and 1H/13C RCSAs) can be performed from spectral-aliased HSQC spectra.
Pulse Programs Code for Bruker:
“Molecule confirmation and structure characterization of pentatriacontatrienyl mycolate in Mycobacterium smegmatis” by M. Llorens-Fons, E. Julián, M. Luquin and M. Pérez-Trujillo. Chemistry and Physics of Lipids, 2018, Accepted Manuscript. DOI: https://doi.org/10.1016/j.chemphyslip.2017.12.006
Mycobacterium smegmatis is often used to study the different components of mycobacterial cell wall. Mycolic acids are important components of mycobacterial cell wall that have been associated with virulence. Recently, a novel lipid containing mycolic acids has been described in M. smegmatis. However, some uncertainties regarding the structure of this molecule named mycolate ester wax have been reported. The objective of this work was to perform an in depth structural study of this molecule for its precise characterization. Using 1H and 13C NMR spectroscopy, the molecular structure of mycolate ester wax found in M. smegmatis has been elucidated. The characterization was complemented with MS analyses. This molecule is formed by a carbon chain with three methyl substituted olefinic units and a mycolate structure with trans double bonds and cis cyclopropane rings. The present molecular study will facilitate the detection and identification of pentatriacontatrienyl mycolate (PTTM) in future studies by the performance of a simple 1D 1H NMR experiment.
“Assessment of biodistribution using mesenchymal stromal cells: Algorithm for study design and challenges in detection methodologies” by Reyes B, Coca MI, Codinach M, López-Lucas MD, Del Mazo-Barbara A, Caminal M, Oliver-Vila I, Cabañas V, S. Lope-Piedrafita, García-López J, Moraleda JM, Fontecha CG, Vives J. Cytotherapy. 2017 :1060-1069. doi: 10.1016/j.jcyt.2017.06.004.
Some members of the SeRMN staff and relatives have run today the 6th edition of the La Cursa de la UAB. This charity race is setting up every year by the UAB with the aim to collect founds supporting the La Marató TV3.
Multiplicity-edited 1H-1H TOCSY experiment
Pau Nolis and Teodor Parella
A 1H-1H TOCSY experiment incorporating 13C multiplicity information is proposed. In addition, broadband 1H homodecoupling in the indirect dimension can be implemented using a perfect BIRD module that affords exclusive 1H chemical shift evolution with full decoupling of all heteronuclear and homonuclear (including 2JHH) coupling constants. As a complement to the normal TOCSY and the recent PSYCHE-TOCSY experiments, this novel multiplicity-edited TOCSY experiment distinguishes between CH/CH3 (phased up) and CH2 (phased down) cross-peaks which facilitates resonance analysis and assignment.
Stereoselectivity of Proline / Cyclobutane Amino Acid-Containing Peptide Organocatalysts for Asymmetric Aldol Additions: a Rationale
J. Org. Chem., Just Accepted Manuscript
Publication Date (Web): November 29, 2017
Several α,β,α- or α,γ,α-tripeptides, consisting of a central cyclobutane β- or γ-amino acid being flanked by two (D)- or (L)-proline residues, have been synthesized and tested as organocatalysts in asymmetric aldol additions. High yields and enantioselectivities have been achieved with α,γ,α-tripeptides, being superior to the peptides containing a cyclobutane β-amino acid residue. This can probably be due to their high rigidity, which hinders the peptide catalysts to adopt the proper active conformation. This reasoning correlates with the major conformation of the peptides in the ground state, as suggested by 1H NMR and computational calculations. The configuration of the aldol products is controlled by the proline chirality, and consequently, the R/S configuration of aldol products can be tuned by the use of either commercially available (D)- or (L)-proline enantiomers. The enantioselectivity in the aldol reactions is reversed if the reactions are carried out in the presence of water or other protic solvents such as methanol. Spectroscopic and theoretical investigations revealed that this effect is not the consequence of conformational changes in the catalyst but rather caused by the participation of a water molecule in the rate determining transition state, in such a way that the preferential nucleophilic attack is oriented to the opposite enantiotopic aldehyde face.
Some of the SeRMN staff presented our last research work about chirality at The first International Conference on Symmetry, Symmetry 2017, that took place from16th to 18th October in Barcelona. Find below a summary of our contribution.
Míriam Pérez-Trujillo presented a lecture entitled: “Chiral Recognition by Dissolution Dynamic Nuclear Polarization NMR Spectroscopy”
Abstract: The recognition of enantiomeric molecules by chemical analytical techniques is still a challenge. A method based on d-DNP (dissolution dynamic nuclear polarization) NMR spectroscopy to study chiral recognition was described for the first time . DNP allows boosting NMR sensitivity by several orders of magnitude, overcoming one of the main limitations of NMR spectroscopy . A method integrating d-DNP and 13C NMR-aided enantiodifferentiation using chiral solvating agents (CSA) was developed, in which only the chiral analyte was hyperpolarized and selectively observed by NMR. The described method enhances the sensitivity of the conventional NMR-based procedure  and lightens the common problem of signal overlapping between analyte and CSA. As proof on concept, racemic metabolite 13C-labeled DL-methionine was enantiodifferentiated by a single-scan 13C NMR experiment. This method entails a step forward in the chiral recognition of small molecules by NMR spectroscopy; it opens new possibilities in situations where the sensitivity is limited, for example, when low analyte concentration available or when measurement of an insensitive nucleus required. The advantages and current limitations of the method, as well as future perspectives, are discussed.
“Direct Monitoring of Exogenous γ-Hydroxybutyric Acid in Body Fluids by NMR Spectroscopy” by M. Palomino-Schätzlein, Y. Wang, A. Brailsford, T. Parella, D. Cowan, C. Legido-Quigley, M. Pérez-Trujillo. Anal. Chem., 2017, 89 (16), pp 8343–8350. DOI: http://dx.doi.org/10.1021/acs.analchem.7b01567
γ-Hydroxybutyric acid (GHB) is a popular drug increasingly associated with cases of drug-facilitated sexual assault (DFSA). Currently, expanding procedures of analysis and having forensic evidence of GHB intake in a long term are mandatory. Up to now, most studies have been performed using GC/MS and LC-MS as analytical platforms, which involve significant manipulation of the sample and, often, indirect measurements. In this work, procedures used in NMR-based metabolomics were applied to a GHB clinical trial on urine and serum. Detection, identification, and briefly quantification of the drug by NMR methods were surveyed, as well as the use of NMR-based metabolomics for the search of potential surrogate biomarkers of GHB consumption. Results demonstrated the suitability of NMR spectroscopy, as a robust nondestructive technique, to fast and directly monitor exogenous GHB in almost intact body fluids and its high potential in the search for metabolites associated with GHB intake. This initial work show some strengths of NMR spectroscopy and standard methods routinely used in the NMR analysis of biological samples to approach the problem. These features could open up new interesting possibilities in future studies, complementing current procedures.
This work on media: spectroscopynow.com / phys.org / sciencedaily.com / canadafreepress.com / forensicmag.com / cbinsights.com