Isolation of bovine β-lactoglobulin from complexes with chitosan

A simple, economical and non-toxic method is described for the solubilization of undenatured β-lactoglobulin (β-lg) from complexes with chitosan. The effect of pH (8-10), ionic strength (0.08-0.3 m) and volume ratio between sodium acetate solutions and whey on the dissociation of β-lg-chitosan complexes was evaluated. Following a single extraction step with the addition of 10 mL of 0.1 m sodium acetate solution at pH 9 to the β-lg-chitosan complexes obtained from 1 mL of cheese-whey, a recovery of 90% of β-lg with a protein purity of 95% was achieved, suggesting that electrostatic interactions play a key role in the complexation of β-lg with chitosan. The presence of free chitosan in solution was ruled out according to gas chromatography with flame-ionization detector analysis after acid hydrolysis. NMR spectroscopy showed that the recovered β-lg after further dialysis had structural features very similar to the native protein.This work was supported by the Comisión Interministerial de Ciencia y Tecnología (CICYT), Project Nos. AGL2004-07227-C02-02 and AGL2004-03322.Peer Reviewe

Selective linkage detection of O-sialoglycan isomers by negative electrospray ionization ion trap tandem mass spectrometry

9 páginas, 6 figuras, 2 esquemas.-- El pdf del artículo es la versión de autor.Sialylated O-linked oligosaccharides are involved in many biological processes, such as cell-cell interactions, cell-substance adhesion, and virus-host interactions. These activities depend on their structure, which is frequently determined by tandem mass spectrometry. However, these spectra are frequently analyzer-dependent, which makes it difficult to develop widely applicable analytical methods. In order to deepen the origin of this behavior, two couples of isomers of sialylated O-linked oligosaccharides, NeuAcα2-3Galβ1-3GalNAc-ol/Galβ1-3(NeuAcα2-6)GalNAc-ol and NeuGcα2-3Galβ1-3GalNAc-ol/Galβ1-3(NeuGcα2-6)GalNAc-ol, were analyzed by liquid chromatography/negative electrospray ionization ion trap tandem mass spectrometry (LC/ESI(−)-MSn) using both an ion trap and a triple quadrupole mass spectrometer. Results clearly showed that while ions obtained in the triple quadrupole instrument fitted very well with the standard fragmentation routes, in the ion trap several intense ions could not be explained by these rules, specially a fragment at m/z 597. Furthermore, this ion was observed in the mass spectrum of those isomers that sialic acid binds to GalNAc by an α2-6 linkage. From the MS3 spectrum of this ion an unexpected structure was deduced, and it led to propose alternative fragmentation pathways. Molecular mechanics calculations suggested that the found atypical route could be promoted by a hydrogen bond located only in α2-6-linked oligosaccharides. It has also been demonstrated that this process follows a slow kinetic, explaining why it cannot be observed using an ion beam-type mass analyzer. In conclusion, ion traps seem to be more appropriate than triple quadrupoles to develop a reliable analytical method to distinguish between isomeric O-linked glycans.Financial support was obtained from projects ANALISYC S-0505/ AGR/000312 from the Comunidad de Madrid, Consolider Ingenio 2010 (FUN-C-FOOD); CSD 2007-00063 from the Ministerio de Educación y Ciencia; and PIF-SIALOBIOTIC 200870F010-1 and -2 from CSIC.Peer reviewe

Sistematización del seguimiento/acreditación de los títulos de doctorado: Un protocolo de buenas prácticas

El objetivo de este proyecto es diseñar una estrategia de monitorización del Programa de Doctorado en Psicología, junto con un protocolo de buenas prácticas para que cualquier titulación de la UCM pueda superar con éxito el proceso de acreditación.Fac. de PsicologíaFALSEVicerrectorado de Calidad, UCMsubmitte

Structural basis of trehalose recognition by the mycobacterial LpqY-SugABC transporter

The Mycobacterium tuberculosis (Mtb) LpqY-SugABC ATP-binding cassette transporter is a recycling system that imports trehalose released during remodelling of the Mtb cell-envelope. As this process is essential for the virulence of the Mtb pathogen it may represent an important target for tuberculosis drug and diagnostic development, but the transporter specificity and molecular determinants of substrate recognition are unknown. To address this, we have determined the structural and biochemical basis of how mycobacteria transport trehalose using a combination of crystallography, STD NMR, molecular dynamics, site-directed mutagenesis, biochemical/biophysical assays and the synthesis of trehalose analogues. This analysis pinpoints key residues of the LpqY substrate binding lipoprotein that dictate substrate-specific recognition and has revealed which disaccharide modifications are tolerated. These findings provide critical insights into how the essential Mtb LpqY-SugABC transporter reuses trehalose and modified analogues, and specifies a framework that can be exploited for the design of new anti-tubercular agents and/or diagnostic tools

Phase I prognostic online (PIPO): A web tool to improve patient selection for oncology early phase clinical trials

Immunotherapy; Phase 1 trials; Prognostic modelInmunoterapia; Ensayos de fase 1; Modelo pronósticoImmunoteràpia; Assajos de fase 1; Model pronòsticPurpose Patient selection in phase 1 clinical trials (Ph1t) continues to be a challenge. The aim of this study was to develop a user-friendly prognostic calculator for predicting overall survival (OS) outcomes in patients to be included in Ph1t with immune checkpoint inhibitors (ICIs) or targeted agents (TAs) based on clinical parameters assessed at baseline. Methods Using a training cohort with consecutive patients from the VHIO phase 1 unit, we constructed a prognostic model to predict median OS (mOS) as a primary endpoint and 3-month (3m) OS rate as a secondary endpoint. The model was validated in an internal cohort after temporal data splitting and represented as a web application. Results We recruited 799 patients (training and validation sets, 558 and 241, respectively). Median follow-up was 21.2 months (m), mOS was 10.2 m (95% CI, 9.3–12.7) for ICIs cohort and 7.7 m (95% CI, 6.6–8.6) for TAs cohort. In the multivariable analysis, six prognostic variables were independently associated with OS – ECOG, number of metastatic sites, presence of liver metastases, derived neutrophils/(leukocytes minus neutrophils) ratio [dNLR], albumin and lactate dehydrogenase (LDH) levels. The phase 1 prognostic online (PIPO) calculator showed adequate discrimination and calibration performance for OS, with C-statistics of 0.71 (95% CI 0.64–0.78) in the validation set. The overall accuracy of the model for 3m OS prediction was 87.2% (95% CI 85%–90%). Conclusions PIPO is a user-friendly objective and interactive tool to calculate specific survival probabilities for each patient before enrolment in a Ph1t. The tool is available at https://pipo.vhio.net/.The research leading to these results has received funding from “la Caixa” Foundation (LCF/PR/CE07/50610001). Cellex Foundation for providing research facilities and equipment. This work was supported by the Accelerator Award (UpSMART) from Fundacion Científica – Asociacion Espanola Contra el Cancer (FC -AECC)/ Associazione Italiana per la Ricerca sul Cancro (AIRC) /Cancer Research United Kingdom (CRUK)

Biological properties of extracellular vesicles and their physiological functions

In the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells. While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system

Biological properties of extracellular vesicles and their physiological functions

María Yáñez-Mó#, Pia R.-M. Siljander#, Zoraida Andreu, Apolonija Bedina Zavec, Francesc E. Borràs, Edit I. Buzas, Krisztina Buzas, Enriqueta Casal, Francesco Cappello, Joana Carvalho, Eva Colás, Anabela Cordeiro-da Silva, Stefano Fais, Juan M. Falcon-Perez, Irene M. Ghobrial, Bernd Giebel, Mario Gimona, Michael Graner, Ihsan Gursel, Mayda Gursel, Niels H. H. Heegaard, An Hendrix30, Peter Kierulf, Katsutoshi Kokubun, Maja Kosanovic, Veronika Kralj-Iglic, Eva-Maria Krämer-Albers, Saara Laitinen, Cecilia Lässer, Thomas Lener, Erzsébet Ligeti, Aija Linē, Georg Lipps, Alicia Llorente, Jan Lötvall, Mateja Manček-Keber, Antonio Marcilla, Maria Mittelbrunn, Irina Nazarenko, Esther N.M. Nolte-‘t Hoen, Tuula A. Nyman, Lorraine O'Driscoll, Mireia Olivan, Carla Oliveira, Éva Pállinger, Hernando A. del Portillo, Jaume Reventós, Marina Rigau, Eva Rohde, Marei Sammar, Francisco Sánchez-Madrid, N. Santarém1, Katharina Schallmoser, Marie Stampe Ostenfeld, Willem Stoorvogel, Roman Stukelj, Susanne G. Van der Grein, M. Helena Vasconcelos, Marca H. M. Wauben and Olivier De WeverIn the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells.While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system.Peer reviewe

Aislamiento, caracterización y modificación de [beta]-lactoglobulina y caseinmacropéptido de suero de quesería

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física Aplicada. Fecha de lectura: 18-09-200

Use of chitosan for selective removal of β-lactoglobulin from whey

A method is described for selective removal of undenatured β-lactoglobulin from cheese whey based on interactions between whey proteins and chitosan. Whey was previously clarified at pH 4.5 with addition of chitosan (25 mg/100 mL), and selective removal of β-lactoglobulin was studied in the pH interval 4.6 to 6.5. Addition of chitosan caused selective precipitation of β-lactoglobulin that increased with pH. The content of β-lactoglobulin in whey decreased as the amount of chitosan added was increased. At pH 6.2, addition of 1.9 to 3.0 mg/mL of chitosan led to complete removal of β-lactoglobulin, whereas at least 80% of the rest of whey proteins remained in solution. The production of cheese whey without β-lactoglobulin could help to expand the applications of dairy by-products in food processing, and to isolate hypoallergenic whey protein concentrates.This work was supported by the Comisión Interministerial de Ciencia y Tecnología (CICYT), Project number AGL2004-07227-C02-02.Peer Reviewe

Tuning plasmid DNA amounts for cost-effective transfections of mammalian cells : when less is more

Altres ajuts: acords transformatius de la UABTransient gene expression (TGE) in mammalian cells is a well-known approach to the fast expression of recombinant proteins. The human cell line HEK (human embryonic kidney) 293F is widely used in this field, due to its adaptability to grow in suspension to high cell densities in serum-free media, amenability to transfection, and production of recombinant proteins in satisfactory quantities for functional and structural analysis. Amounts of plasmid DNA (pDNA) required in transfections for TGE remain high (usually 1 µg pDNA/mL, or even higher), representing a noticeable proportion of the overall cost. Thus, there is an economic need to reduce amounts of coding pDNA in TGE processes. In this work, amounts of both pDNA and transfecting agent used for TGE in HEK 293F cells have been explored in order to reduce them without compromising (or even improving) the productivity of the process in terms of protein yield. In our hands, minimal polyethyleneimine (PEI) cytotoxicity and optimum protein yields were obtained when transfecting at 0.5 µg pDNA/mL (equal to 0.5 µg pDNA/million cells) and a DNA-to-PEI ratio of 1:3, a trend confirmed for several unrelated recombinant proteins. Thus, carefully tuning pDNA and transfecting agent amounts not only reduces the economic costs but also results in higher recombinant protein yields. These results surely have a direct application and interest for the biopharmaceutical industry, always concerned in increasing productivity while decreasing economic costs. • Mammalian cells are widely used to produce recombinant proteins in short times. • Tuning DNA and transfecting agent are of great interest to optimize economic costs. • Reducing DNA and transfecting agent amounts result in higher protein yields