Category Archives: Our Publications

These are the scientific articles published by SeRMN personnel. Posts may contain a short description of the research work objective and relevance, in addition to the abstract of the article, the bibliographic reference, and the article DOI if available.

Neonatal handling enduringly decreases anxiety and stress responses

“Neonatal handling enduringly decreases anxiety and stress responses and reduces hippocampus and amygdala volume in agenetic model of differential anxiety: Behavioral-volumetric associations in the Roman rats trains” by C. Río-Álamos, I. Oliveras, M. A. Piludu, C. Gerbolés, T. Cañete, G. Blázquez, S. Lope-Piedrafita, E. Martínez-Membrives, R. Torrubia, A. Tobeña, and A. Fernández-Teruel. European Neuropsychopharmacology, 2017,  27: 146–158. DOI: 10.1016/j.euroneuro.2016.12.003

The hippocampus and amygdala have been proposed as key neural structures related to anxiety. A more active hippocampus/amygdala system has been related to greater anxious responses in situations involving conflict/novelty. The Roman Low- (RLA) and High-avoidance (RHA) rat strains constitute a genetic model of differential anxiety. Relative to RHA rats, RLA rats exhibit enhanced anxiety/fearfulness, augmented hippocampal/amygdala c-Fos expression following exposure to novelty/conflict, increased hippocampal neuronal density and higher endocrine responses to stress. Neonatal handling (NH) is an environmental treatment with long-lasting anxiety/stress-reducing effects in rodents. Since hippocampus and amygdala volume are supposed to be related to anxiety/fear, it was hypothesized  a greater volume of both areas in RLA than in RHA rats, as well as that NH treatment would reduce anxiety and the volume of both structures. Adult untreated and NH-treated RHA and RLA rats were tested for anxiety, sensorimotor gating (PPI), stress-induced corticosterone and prolactin responses, two-way active avoidance acquisition and in vivo 7 T 1H-Magnetic resonance image.

As expected, untreated RLA rats showed higher anxiety and post-stress hormone responses, as well as greater hippocampus and amygdala volumes than untreated RHA rats. NH decreased anxiety/stress responses, especially in RLA rats, and significantly reduced hippocampus and amygdala volumes in this strain. Dorsal striatum volume was not different between the strains nor it was affected by NH. Finally, there were positive associations (as shown by correlations, factor analysis and multiple regression) between anxiety and PPI and hippocampus/amygdala volumes.

Transgenic mouse model of schizophrenia

“Mutation of the 3-Phosphoinositide-Dependent Protein Kinase 1
(PDK1) Substrate-Docking Site in the Developing Brain Causes
Microcephaly with Abnormal Brain Morphogenesis Independently of
Akt, Leading to Impaired Cognition and Disruptive Behaviors”
by Lluís Cordón-Barris, Sònia Pascual-Guiral, Shaobin Yang, Lydia Giménez-Llort, Silvia Lope-Piedrafita, Carlota Niemeyer, Enrique Claro, Jose M. Lizcano, and Jose R. Bayascas. Mol Cell Biol (2016), 36:2967–2982. DOI:10.1128/MCB.00230-16.

This report shows the involvement of PDK1 downstream effectors other than Akt in mouse neuropsychiatric-like disorders, with potential face and construct validity for negative and cognitive symptoms of schizophrenia. Results point to a prominent function for PIF pocket-dependent kinases as major effectors of this signaling hub downstream of Akt in the etiopathogenesis of schizophrenia that might provide construct validity to the PDK1 L155E mutants.

The phosphoinositide (PI) 3-kinase/Akt signaling pathway plays essential roles during neuronal development. 3-Phosphoinositide-dependent protein kinase 1 (PDK1) coordinates the PI 3-kinase signals by activating 23 kinases of the AGC family, includingAkt. Phosphorylation of a conserved docking site in the substrate is a requisite for PDK1 to recognize, phosphorylate, and activate most of these kinases, with the exception of Akt. This differential mechanism of regulation it has been exploited by generating neuron-specific conditional knock-in mice expressing a mutant form of PDK1, L155E, in which the substrate-docking site binding motif, termed the PIF pocket, was disrupted. As a consequence, activation of all the PDK1 substrates tested except Akt was abolished. The mice exhibited microcephaly, altered cortical layering, and reduced circuitry, leading to cognitive deficits and exacerbated disruptive behavior combined with diminished motivation. The abnormal patterning of the adult brain arises from the reduced ability of the embryonic neurons to polarize and extend their axons, highlighting the essential roles that the PDK1 signaling beyond Akt plays in mediating the neuronal responses that regulate brain development.

Ru complexes studied by NMR

Mononuclear ruthenium compounds bearing N-donor and N-heterocyclic carbene ligands: structure and oxidative catalysis
Hai Jie Liu,   M. Gil-Sepulcre,   L. Francás,   P. Nolis,   T. Parella,   J. Benet-Buchholz,   X. Fontrodona,   J. García-Antón,   N. Romero,   A. Llobet,   Ll. Escriche,   R. Bofill and   X. Sala
Dalton Trans., 2017, Accepted Manuscript

DOI: 10.1039/C6DT04729G

ABSTRACT A new CNNC carbene-phthalazine tetradentate ligand has been synthesised, which under reaction with [Ru(T)Cl3] (T = trpy, tpm, bpea; trpy = 2,2′;6′,2″-terpyridine; tpm = tris(pyrazol-1-yl)methane; bpea = N,N-bis(pyridin-2-ylmethyl)ethanamine) in MeOH or iPrOH undergoes a C-N bond scission due to the nucleophilic attack of a solvent molecule, with the subsequent formation of the mononuclear complexes cis-[Ru(PhthaPz-OR)(trpy)X]n+, [Ru(PhthaPz-OMe)(tpm)X]n+ and trans,fac-[Ru(PhthaPz-OMe)(bpea)X]n+ (X = Cl, n = 1; X = H2O, n = 2; PhthaPz-OR = 1-(4-alkoxyphthalazin-1-yl)-3-methyl-1H-imidazol-3-ium), named 1a+/2a2+ (R = Me), 1b+/2b2+ (R = iPr), 3+/42+ and 5+/62+, respectively. Interestingly, regulation of the stability regions of the different Ru oxidation states is obtained by the different ligand combinations, going from 62+, where Ru(III) is clearly stable and mono-electronic transfers are favoured, to 2a2+/2b2+, where Ru(III) is almost unstable with regards to its disproportion. The catalytic performance of the Ru-OH2 complexes in chemical water oxidation at pH 1.0 points to poor stability (ligand oxidation), with subsequent evolution of CO2 together with O2, especially for 42+ and 62+. In electrochemically driven water oxidation, the highest TOF values are obtained for 2a2+ at pH 1.0. In alkene epoxidation, complexes favouring bi-electronic transfer processes show better performances and selectivities than those favouring mono-electronic transfers, while alkenes containing electron-donor groups promote better performances than those bearing electron-withdrawers. Finally, when cis-β-methylstyrene is employed as substrate, no cis/trans isomerization takes place, thus indicating the existence of a stereospecific process.

Discrimination of stereoisomers with RDCs

“Structural discrimination from in-situ measurement of 1DCH and 2DHH RDCs” by Núria Marcó,  R. R. Gil and Teodor Parella. Magnetic Resonance in Chemistry 2017, DOI: 10.1002/mrc.4575

A fast RDC-assisted strategy involving the simultaneous determination of scalar and total coupling constants from a single 1JCH/2JHH-resolved NMR spectrum is reported. It is shown that the concerted use of the directly measured 1DCH (for all CHn multiplicities) and 2DHH residual dipolar couplings allows an on-the-fly assignment of diastereotopic CH2 protons, as well as of an efficient discrimination between all eight possible diastereoisomeric structures of strychnine, which contains six stereocenters.

Pulse Programs Code for Bruker:

Data set Example:

Extraction of 1JCH for all carbon multiplicities.

“Perfect 1JCH-resolved HSQC: Efficient measurement of one-bond proton-carbon coupling constants along the indirect dimension” by Núria Marcó, A.A. Souza,  Pau Nolis, R. R. Gil and Teodor ParellaJournal of Magnetic resonance 2017, 276, 37-42. DOI: 10.1016/j.jmr.2017.01.002

A versatile 1JCH-resolved HSQC pulse scheme for the speedy, accurate and automated determination of one-bond proton-carbon coupling constants is reported. The implementation of a perfectBIRD element allows a straightforward measurement from the clean doublets obtained along the highly resolved F1 dimension, even for each individual 1JCHa and 1JCHb in diastereotopic HaCHb methylene groups. Real-time homodecoupling during acquisition and other alternatives to minimize accidental signal overlapping in overcrowded spectra are also discussed.

Pulse Programs Code for Bruker:

Data set Example:

New interface to visualize and determine 1JCH.

 1JCH NMR Profile: Identification of key structural features and functionalities by visual observation and direct measurement of one-bond proton-carbon coupling constants” by Núria Marcó, A.A. Souza,  Pau Nolis, Carlos Cobas, R. R. Gil and Teodor ParellaJournal of Organic Chemistry 2017, 276 : 37.42. DOI: 10.1021/acs.joc.6b02873 

A user-friendly NMR interface for the visual and accurate determination of experimental one-bond proton-carbon coupling constants (1JCH) in small molecules is presented. This intuitive 1JCH profile correlates directly delta(1H) and 1JCH facilitates the rapid identification and assignment of 1H signals belonging to key structural elements and functional groups. Illustrative examples are provided for some target molecules including terminal alkynes, strained rings, electronegative substituents or lone-pair bearing heteronuclei.

 

 

Solving JHH measurement in overcrowded regions

Accurate measurement of JHH in overlapped signals by a TOCSY-edited SERF Experiment

André Fredi, Pau Nolis* and Teodor Parella*

Magnetic Resonance in ChemistryDOI: 10.1002/mrc.4572

Selective Refocusing (GSERF or the recent PSYCHEDELIC) experiments were originally designed to determine all proton-proton coupling constants (JHH) for a selected proton resonance. They work for isolated signals on which selective excitation can be successfully applied but, as happens in other selective experiments, fail for overlapped signals. To circumvent this limitation, a doubly-selective TOCSY-GSERF scheme is presented for the measurement of JHH in protons resonating in crowded regions. This new experiment takes advantage of the editing features of an initial TOCSY transfer to uncover hidden resonances that become accessible to perform the subsequent frequency-selective refocusing.

Organogels studied by NMR

Studies on cycloalkane‐based bisamide organogelators: A new example of stochastic chiral symmetry breaking induced by sonication

Ortuno, R. M., Pi-Boleda, B., Sans, M., Campos, M., Nolis, P., Illa, O., Estévez, J. C. and Branchadell, V. (2016), Chem. Eur. J.. Accepted Author Manuscript. doi:10.1002/chem.201604818

Enantiomerically pure C16-alkyl amides derived from cis and trans cycloalkane-1,2-dicarboxylic acids, respectively, have been synthesized and their behaviour as organogelators has been investigated. These compounds include cis/trans diastereomeric cyclobutane and cyclohexane derivatives with the aim to explore the influence of the ring size as well as the relative configuration in their hierarchical self-assembly to form gels. High resolution 1H NMR spectroscopy studies allowed the determination of the dynamics of the gelation process in [D8]-toluene and the sol-gel transition temperature. The morphology and size of the aggregates have been investigated and results have shown that, in the case of cyclobutane derivatives, the cis/trans stereochemistry is not relevant for the gelation behaviour and the properties of the soft-materials obtained, but it is remarkable for cyclohexane diamides, which are better organogelators. The four compounds produce chiral aggregates despite that two of them are meso achiral molecules. We show in this work that this fact is an example of stochastic symmetry breaking induced by sonication. The self-assembly of these molecules has been modelled providing information and support about the structure and the chirality of the aggregates.

RDC measurements and application

joceah_v081i019.inddApplication to the structural discrimination of small molecules containing multiple stereocenters. One-Shot determination of residual dipolar couplings.
Castañar, L.; Garcia, M.; Hellemann, E.; Nolis, P.; Gil, R.; Parella, T.

 

A novel approach for the fast and efficient structural discrimination of molecules containing multiple stereochemical centers is described. A robust Jresolved HSQC experiment affording highly resolved 1JCH/1TCHsplittings along the indirect dimension and homodecoupled 1H signals in the detected dimension is proposed. The experiment enables in-situ distinction of both isotropic and anisotropic components of molecules dissolved incompressed PMMA gels, allowing a rapid and direct one-shot determination of accurate residual dipolar coupling constants from a single NMR spectrum

 

toc_joc_rdc

Mycobacteria clumping increase their capacity to damage macrophages

frontiersmicrobiology

 

“Mycobacteria clumping increase their capacity to damage macrophages” by C. Brambilla, M. Llorens-Fons, E. Julián, E. Noguera-Ortega, C. Tomàs-Martínez, M. Pérez-Trujillo, T. F. Byrd, F. Alcaide and M. Luquin.

Front. Microbiol. 7:1562.  DOI: 10.3389/fmicb.2016.01562

The rough morphotypes of non-tuberculous mycobacteria have been associated with the most severe illnesses in humans. This idea is consistent with the fact that Mycobacterium tuberculosis presents a stable rough morphotype. Unlike smooth morphotypes, the bacilli of rough morphotypes grow close together, leaving no spaces among them and forming large aggregates (clumps). Currently, the initial interaction of macrophages with clumps remains unclear. Thus, we infected J774 macrophages with bacterial suspensions of rough morphotypes of Mycobacterium abscessus containing clumps and suspensions of smooth morphotypes, primarily containing isolated bacilli. Using confocal laser scanning microscopy and electron microscopy, we observed clumps of at least 5 rough-morphotype bacilli inside the phagocytic vesicles of macrophages at 3 hours post-infection. These clumps grew within the phagocytic vesicles, killing 100% of the macrophages at 72 hours post-infection, whereas the proliferation of macrophages infected with smooth morphotypes remained unaltered at 96 hours post-infection. Thus, macrophages phagocytose large clumps, exceeding the bactericidal capacities of these cells. Furthermore, proinflammatory cytokines and granuloma-like structures were only produced by macrophages infected with rough morphotypes. Thus, the present study provides a foundation for further studies that consider mycobacterial clumps as virulence factors.

fig8

Figure. Content of GPL and structure of mycolic acids. (A) 1-D TLC analysis of the crude lipid extracts of M. abscessus strains. (B) 1H-NMR spectra of purified mycolic acid methyl esters from M. abscessus. (C) Relative molar ratios of molecular moieties cis-db, trans-db, cis-cp and trans-cp of mycolic acid methyl esters from M. abscessus.