Structure, conformational dynamics and formation of large amyloids: the case of alpha-synuclein fibrils

In my thesis, I have focused on new methodology development combined with state-of-the-art solid-state nuclear magnetic resonance (NMR) experiments with scanning transmission electron microscopy (STEM) to obtain atomic level structural information of the alpha-synuclein (AS) fibrils and the mechanism of their formation; We first investigated the effect of protein deuteration and 1H decoupling optimization to maximize the resolution and sensitivity of biomolecular solid-state NMR; We then applied state-of-the-art solid-state NMR experiments to do a detailed structural characterization and conformational dynamics of AS fibrils using improved sample preparation and labeling schemes; These results show that the core of the fibrils extends for about 70 residues with a repeated secondary structure motif; Additionally, it demonstrates that the three mutation sites (A30P, E46K, A53T) are located in structured regions of the fibrils; Upon mutation, we have shown that the structure suffers major and minor perturbations by E46K and A53T, respectively; while the structure is unaltered by A30P; The fibril formation has also been investigated by capturing the transition from α-helical to β-sheet at the atomic level using solid-state NMR; Additionally, to investigate the AS fold, the mass-per-length (MPL) measurement of the fibrils has been obtained using STEM that together with solid-state NMR restraints have been used to propose possible models of how the fibrils arrange; Finally, initial results for solving 3D high-resolution structures of large proteins with new computational methods have been investigated

Exploration of the One-Bead One-Compound Methodology for the Design of Prolyl Oligopeptidase Substrates

Here we describe the design, synthesis and evaluation of the first solid-phase substrates for prolyl oligopeptidase (POP), a cytosolic serine peptidase associated with schizophrenia, bipolar affective disorder and related neuropsychiatric disorders. This study seeks to contribute to the future design of a one-bead one-compound (OBOC) peptide library of POP substrates, based on an intramolecular energy transfer substrate. Unexpectedly, the enzymatic evaluation of the substrates attached on solid-phase by means of the HMBA linker were cleaved through the ester bond, thereby suggesting an unknown esterase activity of POP, in addition to its known peptidase activity. By performing multiple activity assays, we have confirmed the esterase activity of this enzyme and its capacity to process the substrates on solid-phase. Finally, we tested a new linker, compatible with both the solid-phase peptide-synthesis used and the enzymatic assay, for application in the future design of an OBOC library

Endoscopic radiofrequency ablation for APC refractory gastric antral vascular ectasia using the HALO90 system in a kidney transplant candidate

Gastric antral vascular ectasia (GAVE) is a rare but important cause of gastrointestinal bleeding and anemia. Endoscopic ablation, such as argon plasma coagulation (APC), is usually successful, but treatment-refractory cases do occur. Recently, radiofrequency ablation (RFA) has been described as an alternative therapeutic option for GAVE, or actinic proctitis, with positive results and minor complications

Amphotericin forms an extramembranous and fungicidal sterol sponge.

For over 50 years, amphotericin has remained the powerful but highly toxic last line of defense in treating life-threatening fungal infections in humans with minimal development of microbial resistance. Understanding how this small molecule kills yeast is thus critical for guiding development of derivatives with an improved therapeutic index and other resistance-refractory antimicrobial agents. In the widely accepted ion channel model for its mechanism of cytocidal action, amphotericin forms aggregates inside lipid bilayers that permeabilize and kill cells. In contrast, we report that amphotericin exists primarily in the form of large, extramembranous aggregates that kill yeast by extracting ergosterol from lipid bilayers. These findings reveal that extraction of a polyfunctional lipid underlies the resistance-refractory antimicrobial action of amphotericin and suggests a roadmap for separating its cytocidal and membrane-permeabilizing activities. This new mechanistic understanding is also guiding development of what are to our knowledge the first derivatives of amphotericin that kill yeast but not human cells

Site-specific perturbations of alpha-synuclein fibril structure by the Parkinson's disease associated mutations A53T and E46K.

PMCID: PMC3591419This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Parkinson's disease (PD) is pathologically characterized by the presence of Lewy bodies (LBs) in dopaminergic neurons of the substantia nigra. These intracellular inclusions are largely composed of misfolded α-synuclein (AS), a neuronal protein that is abundant in the vertebrate brain. Point mutations in AS are associated with rare, early-onset forms of PD, although aggregation of the wild-type (WT) protein is observed in the more common sporadic forms of the disease. Here, we employed multidimensional solid-state NMR experiments to assess A53T and E46K mutant fibrils, in comparison to our recent description of WT AS fibrils. We made de novo chemical shift assignments for the mutants, and used these chemical shifts to empirically determine secondary structures. We observe significant perturbations in secondary structure throughout the fibril core for the E46K fibril, while the A53T fibril exhibits more localized perturbations near the mutation site. Overall, these results demonstrate that the secondary structure of A53T has some small differences from the WT and the secondary structure of E46K has significant differences, which may alter the overall structural arrangement of the fibrils

Obtaining bibliographical references for the elaboration of the Final Degree Project of Pharmacy

[spa] En el marco de la asignatura del Trabajo Final de Grado de Farmacia de la Universidad de Barcelona, las bibliotecarias del CRAI-Biblioteca de la Facultad de Farmacia imparten una sesión de formación optativa sobre búsqueda bibliográfica en bases de datos especializadas. A partir del análisis de los dos ejemplos trabajados en la sesión más dos temas asignados a estudiantes de este curso académico, se recomienda en qué plataformas y con qué mecánica tiene que proceder el estudiante para una obtención óptima de resultados para su bibliografía.[eng] Within the framework of the subject of Final Degree Project of Pharmacy at the University of Barcelona, the librarians of the CRAI-Library of the Faculty of Pharmacy offer an optional training session on bibliographic search in specialized databases. From the analysis of the two examples worked in the session plus two topics assigned to students of this academic year, the platforms and with what mechanics the student has to proceed in order to obtain optimal results for his / her project’s bibliography are recommended

Aportacions de la cromatografia al coneixement dels lípids: olis i greixos

La cromatografia, concretament la de gasos (GC, de l'anglès gas chromatography), ha fet possible caracteritzar els materials lipídics a nivell molecular i ha permès posar a punt mètodes ràpids i de gran reproductibilitat. En aquest treball, amb un enfocament històric, es descriuen alguns dels resultats de l'aplicació d'aquesta tecnologia analítica, que ha fet possible distingir clarament les diferents identitats i qualitats dels diversos tipus d'olis, greixos i materials lipídics. Per altra part, també s'explica com, gràcies a la GC, s'han resolt alguns greus incidents amb aquests importants productes alimentaris, deguts a contaminacions i a fraus. També es fa esment al tema de gran actualitat dels isòmers trans de l'àcid oleic i a les dificultats que implica la seva identificació analítica. S'aporten alguns resultats de correlació entre retenció cromatogràfica i estructura molecular, que contribueixen a la identificació d'alguns isòmers de configuració de l'àcid oleic trans.Gas chromatography (GC) has made it possible to characterize lipid materials at molecular level and it has also allowed the development of rapid and high-reproducibility analytical methods. With a historical focus, this paper describes some of the results obtained with this analytical technique relating to the characterization of various types of oils, fats and lipid materials. Likewise, this paper explains how this technique has allowed to solve some serious incidents stemming from contamination and fraud. It also deals with a subject of great interest at the present time: the trans isomers of oleic acid and the difficulty of their identification by analysis. Also presented in this paper are the results obtained in the identification of trans-oleic acid configuration isomers thanks to the application of the methodolog

Prospective individual patient data meta-analysis of two randomized trials on convalescent plasma for COVID-19 outpatients

Data on convalescent plasma (CP) treatment in COVID-19 outpatients are scarce. We aimed to assess whether CP administered during the first week of symptoms reduced the disease progression or risk of hospitalization of outpatients. Two multicenter, double-blind randomized trials (NCT04621123, NCT04589949) were merged with data pooling starting when = 50 years and symptomatic for <= 7days were included. The intervention consisted of 200-300mL of CP with a predefined minimum level of antibodies. Primary endpoints were a 5-point disease severity scale and a composite of hospitalization or death by 28 days. Amongst the 797 patients included, 390 received CP and 392 placebo; they had a median age of 58 years, 1 comorbidity, 5 days symptoms and 93% had negative IgG antibody-test. Seventy-four patients were hospitalized, 6 required mechanical ventilation and 3 died. The odds ratio (OR) of CP for improved disease severity scale was 0.936 (credible interval (CI) 0.667-1.311); OR for hospitalization or death was 0.919 (CI 0.592-1.416). CP effect on hospital admission or death was largest in patients with <= 5 days of symptoms (OR 0.658, 95%CI 0.394-1.085). CP did not decrease the time to full symptom resolution

TFG 2013/2014

Amb aquesta publicació, EINA, Centre universitari de Disseny i Art adscrit a la Universitat Autònoma de Barcelona, dóna a conèixer el recull dels Treballs de Fi de Grau presentats durant el curs 2013-2014. Voldríem que un recull com aquest donés una idea més precisa de la tasca que es realitza a EINA per tal de formar nous dissenyadors amb capacitat de respondre professionalment i intel·lectualment a les necessitats i exigències de la nostra societat. El treball formatiu s’orienta a oferir resultats que responguin tant a paràmetres de rigor acadèmic i capacitat d’anàlisi del context com a l’experimentació i la creació de nous llenguatges, tot fomentant el potencial innovador del disseny.Con esta publicación, EINA, Centro universitario de diseño y arte adscrito a la Universidad Autónoma de Barcelona, da a conocer la recopilación de los Trabajos de Fin de Grado presentados durante el curso 2013-2014. Querríamos que una recopilación como ésta diera una idea más precisa del trabajo que se realiza en EINA para formar nuevos diseñadores con capacidad de responder profesional e intelectualmente a las necesidades y exigencias de nuestra sociedad. El trabajo formativo se orienta a ofrecer resultados que respondan tanto a parámetros de rigor académico y capacidad de análisis, como a la experimentación y la creación de nuevos lenguajes, al tiempo que se fomenta el potencial innovador del diseño.With this publication, EINA, University School of Design and Art, affiliated to the Autonomous University of Barcelona, brings to the public eye the Final Degree Projects presented during the 2013-2014 academic year. Our hope is that this volume might offer a more precise idea of the task performed by EINA in training new designers, able to speak both professionally and intellectually to the needs and demands of our society. The educational task is oriented towards results that might respond to the parameters of academic rigour and the capacity for contextual analysis, as well as to considerations of experimentation and the creation of new languages, all the while reinforcing design’s innovative potential