Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Marta Vergara-Irigaray is active.

Publication


Featured researches published by Marta Vergara-Irigaray.


Journal of Bacteriology | 2009

Protein A-Mediated Multicellular Behavior in Staphylococcus aureus

Nekane Merino; Alejandro Toledo-Arana; Marta Vergara-Irigaray; Jaione Valle; Cristina Solano; Enrique Calvo; Juan Antonio López; Timothy J. Foster; José R. Penadés; Iñigo Lasa

The capacity of Staphylococcus aureus to form biofilms on host tissues and implanted medical devices is one of the major virulence traits underlying persistent and chronic infections. The matrix in which S. aureus cells are encased in a biofilm often consists of the polysaccharide intercellular adhesin (PIA) or poly-N-acetyl glucosamine (PNAG). However, surface proteins capable of promoting biofilm development in the absence of PIA/PNAG exopolysaccharide have been described. Here, we used two-dimensional nano-liquid chromatography and mass spectrometry to investigate the composition of a proteinaceous biofilm matrix and identified protein A (spa) as an essential component of the biofilm; protein A induced bacterial aggregation in liquid medium and biofilm formation under standing and flow conditions. Exogenous addition of synthetic protein A or supernatants containing secreted protein A to growth media induced biofilm development, indicating that protein A can promote biofilm development without being covalently anchored to the cell wall. Protein A-mediated biofilm formation was completely inhibited in a dose-dependent manner by addition of serum, purified immunoglobulin G, or anti-protein A-specific antibodies. A murine model of subcutaneous catheter infection unveiled a significant role for protein A in the development of biofilm-associated infections, as the amount of protein A-deficient bacteria recovered from the catheter was significantly lower than that of wild-type bacteria when both strains were used to coinfect the implanted medical device. Our results suggest a novel role for protein A complementary to its known capacity to interact with multiple immunologically important eukaryotic receptors.


Proceedings of the National Academy of Sciences of the United States of America | 2011

Genome-wide antisense transcription drives mRNA processing in bacteria

Iñigo Lasa; Alejandro Toledo-Arana; Alexander Dobin; Maite Villanueva; I. R. de los Mozos; Marta Vergara-Irigaray; Victor Segura; Delphine Fagegaltier; José R. Penadés; Jaione Valle; Cristina Solano; Thomas R. Gingeras

RNA deep sequencing technologies are revealing unexpected levels of complexity in bacterial transcriptomes with the discovery of abundant noncoding RNAs, antisense RNAs, long 5′ and 3′ untranslated regions, and alternative operon structures. Here, by applying deep RNA sequencing to both the long and short RNA fractions (<50 nucleotides) obtained from the major human pathogen Staphylococcus aureus, we have detected a collection of short RNAs that is generated genome-wide through the digestion of overlapping sense/antisense transcripts by RNase III endoribonuclease. At least 75% of sense RNAs from annotated genes are subject to this mechanism of antisense processing. Removal of RNase III activity reduces the amount of short RNAs and is accompanied by the accumulation of discrete antisense transcripts. These results suggest the production of pervasive but hidden antisense transcription used to process sense transcripts by means of creating double-stranded substrates. This process of RNase III-mediated digestion of overlapping transcripts can be observed in several evolutionarily diverse Gram-positive bacteria and is capable of providing a unique genome-wide posttranscriptional mechanism to adjust mRNA levels.


Journal of Bacteriology | 2005

Staphylococcus aureus Develops an Alternative, ica-Independent Biofilm in the Absence of the arlRS Two-Component System

Alejandro Toledo-Arana; Nekane Merino; Marta Vergara-Irigaray; Michel Débarbouillé; José R. Penadés; Iñigo Lasa

The biofilm formation capacity of Staphylococcus aureus clinical isolates is considered an important virulence factor for the establishment of chronic infections. Environmental conditions affect the biofilm formation capacity of S. aureus, indicating the existence of positive and negative regulators of the process. The majority of the screening procedures for identifying genes involved in biofilm development have been focused on genes whose presence is essential for the process. In this report, we have used random transposon mutagenesis and systematic disruption of all S. aureus two-component systems to identify negative regulators of S. aureus biofilm development in a chemically defined medium (Hussain-Hastings-White modified medium [HHWm]). The results of both approaches coincided in that they identified arlRS as a repressor of biofilm development under both steady-state and flow conditions. The arlRS mutant exhibited an increased initial attachment as well as increased accumulation of poly-N-acetylglucosamine (PNAG). However, the biofilm formation of the arlRS mutant was not affected when the icaADBC operon was deleted, indicating that PNAG is not an essential compound of the biofilm matrix produced in HHWm. Disruption of the major autolysin gene, atl, did not produce any effect on the biofilm phenotype of an arlRS mutant. Epistatic experiments with global regulators involved in staphylococcal-biofilm formation indicated that sarA deletion abolished, whereas agr deletion reinforced, the biofilm development promoted by the arlRS mutation.


Infection and Immunity | 2009

Relevant Role of Fibronectin-Binding Proteins in Staphylococcus aureus Biofilm-Associated Foreign-Body Infections

Marta Vergara-Irigaray; Jaione Valle; Nekane Merino; Cristina Latasa; Begoña García; Igor Ruiz de los Mozos; Cristina Solano; Alejandro Toledo-Arana; José R. Penadés; Iñigo Lasa

ABSTRACT Staphylococcus aureus can establish chronic infections on implanted medical devices due to its capacity to form biofilms. Analysis of the factors that assemble cells into a biofilm has revealed the occurrence of strains that produce either a polysaccharide intercellular adhesin/poly-N-acetylglucosamine (PIA/PNAG) exopolysaccharide- or a protein-dependent biofilm. Examination of the influence of matrix nature on the biofilm capacities of embedded bacteria has remained elusive, because a natural strain that readily converts between a polysaccharide- and a protein-based biofilm has not been studied. Here, we have investigated the clinical methicillin (meticillin)-resistant Staphylococcus aureus strain 132, which is able to alternate between a proteinaceous and an exopolysaccharidic biofilm matrix, depending on environmental conditions. Systematic disruption of each member of the LPXTG surface protein family identified fibronectin-binding proteins (FnBPs) as components of a proteinaceous biofilm formed in Trypticase soy broth-glucose, whereas a PIA/PNAG-dependent biofilm was produced under osmotic stress conditions. The induction of FnBP levels due to a spontaneous agr deficiency present in strain 132 and the activation of a LexA-dependent SOS response or FnBP overexpression from a multicopy plasmid enhanced biofilm development, suggesting a direct relationship between the FnBP levels and the strength of the multicellular phenotype. Scanning electron microscopy revealed that cells growing in the FnBP-mediated biofilm formed highly dense aggregates without any detectable extracellular matrix, whereas cells in a PIA/PNAG-dependent biofilm were embedded in an abundant extracellular material. Finally, studies of the contribution of each type of biofilm matrix to subcutaneous catheter colonization revealed that an FnBP mutant displayed a significantly lower capacity to develop biofilm on implanted catheters than the isogenic PIA/PNAG-deficient mutant.


Microbes and Infection | 2010

Extracellular proteases inhibit protein-dependent biofilm formation in Staphylococcus aureus

Miguel Martí; María Pilar Trotonda; María Ángeles Tormo-Más; Marta Vergara-Irigaray; Ambrose L. Cheung; Iñigo Lasa; José R. Penadés

In Staphylococcus aureus, biofilm formation can be associated with the production of surface-anchored proteins, including Bap, SasG, FnBPs or Spa. By mutational analysis, and using a model strain in which biofilm formation was Bap-dependent, we found that sigma(B) was essential for protein-dependent biofilm development. Non-polar mutations of sigma(B) in genetically unrelated S. aureus strains lowered the Bap expression and completely impaired biofilm development. Although Northern blot analysis showed a slight reduction in bap transcription, we demonstrated that Aur and SspA, two proteases that are overexpressed in the sigB mutant strain and are capable of degrading Bap, inhibit biofilm formation. Interestingly, a double sigB-agr mutant, which showed a diminished capacity to express extracellular proteases, was able to restore biofilm formation. Since the vast majority of the S. aureus global regulators control the expression of the extracellular proteases, the results of this work demonstrate the existence of a new pathway controlling protein-mediated biofilm formation in which different global regulators modulate biofilm formation by controlling the expression of S. aureus extracellular proteases.


Microbiology | 2008

Wall teichoic acids are dispensable for anchoring the PNAG exopolysaccharide to the Staphylococcus aureus cell surface

Marta Vergara-Irigaray; Tomas Maira-Litran; Nekane Merino; Gerald B. Pier; José R. Penadés; Iñigo Lasa

Biofilm formation in Staphylococcus aureus is usually associated with the production of the poly-N-acetylglucosamine (PNAG) exopolysaccharide, synthesized by proteins encoded by the icaADBC operon. PNAG is a linear beta-(1-6)-linked N-acetylglucosaminoglycan that has to be partially deacetylated and consequently positively charged in order to be associated with bacterial cell surfaces. Here, we investigated whether attachment of PNAG to bacterial surfaces is mediated by ionic interactions with the negative charge of wall teichoic acids (WTAs), which represent the most abundant polyanions of the Gram-positive bacterial envelope. We generated WTA-deficient mutants by in-frame deletion of the tagO gene in two genetically unrelated S. aureus strains. The DeltatagO mutants were more sensitive to high temperatures, showed a higher degree of cell aggregation, had reduced initial adherence to abiotic surfaces and had a reduced capacity to form biofilms under both steady-state and flow conditions. However, the levels as well as the strength of the PNAG interaction with the bacterial cell surface were similar between DeltatagO mutants and their corresponding wild-type strains. Furthermore, double DeltatagO DeltaicaADBC mutants displayed a similar aggregative phenotype to that of single DeltatagO mutants, indicating that PNAG is not responsible for the aggregative behaviour observed in DeltatagO mutants. Overall, the absence of WTAs in S. aureus had little effect on PNAG production or anchoring to the cell surface, but did affect the biofilm-forming capacity, cell aggregative behaviour and the temperature sensitivity/stability of S. aureus.


Journal of Bacteriology | 2007

σB Regulates IS256-Mediated Staphylococcus aureus Biofilm Phenotypic Variation

Jaione Valle; Marta Vergara-Irigaray; Nekane Merino; José R. Penadés; Iñigo Lasa

Biofilm formation in Staphylococcus aureus is subject to phase variation, and biofilm-negative derivatives emerge sporadically from a biofilm-positive bacterial population. To date, the only known mechanism for generating biofilm phenotypic variation in staphylococci is the reversible insertion/excision of IS256 in biofilm-essential genes. In this study, we present evidence suggesting that the absence of the sigma(B) transcription factor dramatically increases the rate of switching to the biofilm-negative phenotype in the clinical isolate S. aureus 15981, under both steady-state and flow conditions. The phenotypic switching correlates with a dramatic increase in the number of IS256 copies in the chromosomes of biofilm-negative variants, as well as with an augmented IS256 insertion frequency into the icaC and the sarA genes. IS256-mediated biofilm switching is reversible, and biofilm-positive variants could emerge from biofilm-negative sigma(B) mutants. Analysis of the chromosomal insertion frequency using a recombinant IS256 element tagged with an erythromycin marker showed an almost three-times-higher transposition frequency in a Deltasigma(B) strain. However, regulation of IS256 activity by sigma(B) appears to be indirect, since transposase transcription is not affected in the absence of sigma(B) and IS256 activity is inhibited to wild-type levels in a Deltasigma(B) strain under NaCl stress. Overall, our results identify a new role for sigma(B) as a negative regulator of insertion sequence transposition and support the idea that deregulation of IS256 activity abrogates biofilm formation capacity in S. aureus.


PLOS Genetics | 2013

Base Pairing Interaction between 5′- and 3′-UTRs Controls icaR mRNA Translation in Staphylococcus aureus

Igor Ruiz de los Mozos; Marta Vergara-Irigaray; Victor Segura; Maite Villanueva; Nerea Bitarte; Margarida Saramago; Susana Domingues; Cecília M. Arraiano; Pierre Fechter; Pascale Romby; Jaione Valle; Cristina Solano; Iñigo Lasa; Alejandro Toledo-Arana

The presence of regulatory sequences in the 3′ untranslated region (3′-UTR) of eukaryotic mRNAs controlling RNA stability and translation efficiency is widely recognized. In contrast, the relevance of 3′-UTRs in bacterial mRNA functionality has been disregarded. Here, we report evidences showing that around one-third of the mapped mRNAs of the major human pathogen Staphylococcus aureus carry 3′-UTRs longer than 100-nt and thus, potential regulatory functions. We selected the long 3′-UTR of icaR, which codes for the repressor of the main exopolysaccharidic compound of the S. aureus biofilm matrix, to evaluate the role that 3′-UTRs may play in controlling mRNA expression. We showed that base pairing between the 3′-UTR and the Shine-Dalgarno (SD) region of icaR mRNA interferes with the translation initiation complex and generates a double-stranded substrate for RNase III. Deletion or substitution of the motif (UCCCCUG) within icaR 3′-UTR was sufficient to abolish this interaction and resulted in the accumulation of IcaR repressor and inhibition of biofilm development. Our findings provide a singular example of a new potential post-transcriptional regulatory mechanism to modulate bacterial gene expression through the interaction of a 3′-UTR with the 5′-UTR of the same mRNA.


Nucleic Acids Research | 2018

The regulon of the RNA chaperone CspA and its auto-regulation in Staphylococcus aureus

Carlos J Caballero; Pilar Menendez-Gil; Arancha Catalan-Moreno; Marta Vergara-Irigaray; Begoña García; Victor Segura; Naiara Irurzun; Maite Villanueva; Igor Ruiz de los Mozos; Cristina Solano; Iñigo Lasa; Alejandro Toledo-Arana

Abstract RNA-binding proteins (RBPs) are essential to fine-tune gene expression. RBPs containing the cold-shock domain are RNA chaperones that have been extensively studied. However, the RNA targets and specific functions for many of them remain elusive. Here, combining comparative proteomics and RBP-immunoprecipitation-microarray profiling, we have determined the regulon of the RNA chaperone CspA of Staphylococcus aureus. Functional analysis revealed that proteins involved in carbohydrate and ribonucleotide metabolism, stress response and virulence gene expression were affected by cspA deletion. Stress-associated phenotypes such as increased bacterial aggregation and diminished resistance to oxidative-stress stood out. Integration of the proteome and targetome showed that CspA post-transcriptionally modulates both positively and negatively the expression of its targets, denoting additional functions to the previously proposed translation enhancement. One of these repressed targets was its own mRNA, indicating the presence of a negative post-transcriptional feedback loop. CspA bound the 5′UTR of its own mRNA disrupting a hairpin, which was previously described as an RNase III target. Thus, deletion of the cspA 5′UTR abrogated mRNA processing and auto-regulation. We propose that CspA interacts through a U-rich motif, which is located at the RNase III cleavage site, portraying CspA as a putative RNase III-antagonist.


Archive | 2016

Caracterización funcional de las chaperonas de RNA en Staphylococcus aureus

Carlos José Caballero Sánchez; Arancha Catalán Moreno; Marta Vergara-Irigaray; Begoña García; Cristina Solano Goñi; Iñigo Lasa; Alejandro Toledo-Arana

Tesis llevada a cabo para conseguir el grado de Doctor por la Universidad de Complutense de Madrid.--2018-01-15.--Sobresaliente cum laudeContiene 7 documentos (1. Objetivos, alcance y publicaciones. 2. Registro y codigo) y 5 con el softwareespanolLas ciber amenazas afectan a todo tipo de organizaciones, causando frecuentes y costosos impactos globalmente. Recientemente, han surgido productos de ciberseguro con el potencial de reducir el impacto de los riesgos en el ciberespacio. Sin embargo, aun tienen que madurar. En este articulo presentamos varios modelos de analisis de riesgos que podrian facilitar la implantacion y adopcion de ciberseguros. Estos modelos, descritos como diagramas de influencia y diagramas de influencia bi-agente, aportan un marco para estimar el impacto economico de los ciber riesgos a los que se enfrentan aseguradores y asegurados, asi como tambien para calcular sus estrategias optimas de mitigacion y transferencia del riesgo. EnglishCyber threats affect all kinds of organisations with frequent and costly impacts worldwide. Cyber insurance products have recently emerged with the potential of lowering the impact of cyberspace risks. However, they have yet to mature. In this paper we present several risk analysis models that may facilitate the implementation and adoption of cyber insurance. These models, described in terms of influence diagrams and bi-agent influence diagrams, provide a framework for estimating the economic impact of cyber risks that may face insurers and insurees as well as calculating their optimal risk mitigation and transfer strategies.Trabajo presentado a la III Iberoamerican Conference on Supercritical Fluids celebrada en Cartagena de Indias (Colombia) del 1 al 5 de abril de 2013.Trabajo presentado a la 26th IAEA Fusion Energy Conference, celebrada en Kyoto (Japon) del 17 al 22 de octubre de 2016.The Joint Iberian Meeting on Atomic and Molecular Physics (IBER), Barcelona, September 12-14th, 2017. -- http://iber2017.com/index.phpPoster presentado en el 10o Congreso de la Asociacion Iberica de Endocrinologia Comparada AIEC, celebrado en Castellon, Espana, del 23 al 25 de septiembre de 2015Resumen del trabajo presentado a la XI Reunion del Grupo de Microbiologia Molecular, celebrada en Sevilla del 6 al 8 de septiembre de 2016.Chinchilla-Rodriguez, Zaida; Miguel, Sandra; Perianes-Rodriguez, Antonio; Ovalle-Perandones, Antonia; Olmeda-Gomez, Carlos. (2016). Autonomy vs. dependency of scientific collaboration in scientific performance . 21st International Conference on Science and Technology Indicators, STI2016. Valencia, Spain, 14-16 September 2016XXV National Spectroscopy Meeting (XXV RNE), IX Iberian Spectroscopy Conference (IX CIE), Alicante, 20th-22nd July, 2016Resumen del trabajo presentado a la 43rd International Conference on Micro and Nano Engineering (MNE), celebrada en Braga (Portugal) del 18 al 22 de septiembre de 2017.Contiene 7 documentos (1. Objetivos, alcance y publicaciones. 2. Registro, interface y codigo) y 5 con el softwarePoster presentado en el congreso 4th SCARCE International Conference, celebrado en Cadiz, Espana el 25 y 26 de noviembre de 2013We present a Cultural Heritage conceptual data model built under the European INSPIRE ( Infrastructure for Spatial Information in the European Community ) Directive. Our model develops the Data Specification on Protected Sites , part of the INSPIRE Annex I. Hence its orientation towards georeferenced heritage data. The data model has been developed by an interdisciplinary group made up of specialists in the field of Geomatics and Cultural Heritage. It is our aim to achieve a generic, extendable and interoperable schema. It should be generic enough to embrace all kind of protected heritage data, from an ancient pilgrim’s way to the last artifact found in an archaeological excavation, extendable to allow any kind of data producer to adapt the model to the nature of their own information and interoperable to combine spatial data sets from different sources through network services, via Internet. The achievement of these three characteristics features international norms and standards referred to our kind of data. This implies adaptation to INSPIRE as well as to several ISO norms: ISO 19100 series regarding geographical information, ISO 21127 (CIDOC-CRM Model) for heritage thematic data and ISO 15836 (Dublin Core) for document resources. The data model comprehends two main dimensions: cultural entities in a strict sense, and the legislative figures created to protect them. This allows for the representation of cultural objects (i.e. historical buildings or archaeological sites) and their link to their legislative protection, keeping them as separate realities. In order to describe the data model, an international common language has been used: UML (Unified Modeling Language), a standard itself. Thus, we present a class-diagram depicting all legal and cultural entities, in the form of classes with their corresponding relations, attributes, constraints and stereotypes.Trabajo presentado en el 11th Spanish-Italian Symposium on Organic Chemistry SISOC-XI celebrado en San Sebastian (Espana), del 13 al 15 de julio de 2016.Trabajo presentado en el XVIII Congreso Peruano de Geologia, celebrado en Lima (Peru), del 16 al 19 de octubre de 2016Poster presentado en las XXXIII Jornadas de la Asociacion Espanola de Entomologia, celebradas en Almeria, del 15 al 18 de noviembre de 2017This research has been funded by the Spanish Ministry of Economy and Competitiveness, through research projects POSTFIRE (CGL2013-47862-C2-1-R) and GEOFIRE (CGL2012-38655-C04-01)The main contribution of this work is the improvement of the efficiency of a PEMFC power system while guaranteeing conditions that also improve its durability. Adopting the NMPC scheme with the distributed parameter model and the nonlinear observer, the efficiency of the PEMFC-based system can be maximized guaranteeing at the same time the appropriate internal gas concentration profiles to avoid global and local hydrogen and oxygen starvation and proper membrane humidification.Trabajo presentado en la 13a Reunion de la Red Espanola de Bacterias Lacticas (RedBAL), celebrada en Madrid (Espana) del 17 al 18 de junio de 2019Memoria de tesis doctoral presentada por Uxue Tilves Matheu para obtener el titulo de Doctora en Ciencias del Mar por la Universitat Politecnica de Catalunya (UPC), realizada bajo la direccion de la Dra. Ana Maria Sabates Freijo y de la Dra. Veronica Lorena Fuentes del Institut de Ciencies del Mar (ICM-CSIC).-- 149 pages, appendicesTrabajo presentado por Nuria Vallverdu Coll para la obtencion del grado de Master universitario en investigacion basica y aplicada en recursos cinegeticos, realizado en el Instituto de Investigacion en Recursos Cinegeticos (IREC, CSIC-UCLM-JCCM).Resumen del poster presentado a la 7th International Conference on Polyphenols and Health, celebrada en Tours (Francia) del 27 al 30 de octubre de 2015.Trabajo financiado con el Proyecto DR3AMCGL2014-55118 del MINECO (Proyecto coordinado del proyecto SALTACRES).Trabajo presentado en el Congreso Iberoamericano de Hidrogeno y Pilas de Combustible, celebrado en Barcelona (Espana) del 15 al 17 de octubre de 2014.El presente articulo describe el empleo del flujo de diseno basado en modelos para el desarrollo de bloques reconfigurables automaticamente para el procesado de imagenes sobre FPGA. Para ello se han concebido arquitecturas hardware que aprovechan caracteristicas especificas de algunos algoritmos de procesado y que pueden ser modificadas a traves de un novedoso procedimiento software. Este aspecto, unido a las restantes opciones de parametrizacion de los diferentes modulos, permite liberar al disenador de los detalles especificos de las implementaciones hardware asi como adaptar el consumo de recursos del FPGA a las necesidades de la aplicacion. El proceso de reconfiguracion automatica se ilustra con el bloque de convolucion generico realizando comparaciones entre implementaciones de diferentes arquitecturas sobre un FPGA Spartan-6 LX45.Trabajo presentado en el 8th European Meeting on Solar Chemistry and Photocatalysis, celebrado en Salonica (Grecia) del 25 al 28 de Junio de 2014.Resumen del poster presentado a las I Jornadas Cientificas del CIAL celebradas el 5 de junio de 2014 en Madrid.-- et al.Trabajo presentado en el 4th International Conodont Symposium, celebrado en Valencia (Espana), del 25 al 30 de junio de 2017Comunicacion presentada en el Aquaculture Europe 2014, celebrado en Donostia-San Sebastian, Espana, del 14 al 17 de octubre de 2014Triptico de la reunion celebrada en la Universidad de Murcia del 12 al 14 de Noviembre de 2015.Trabajo presentado en la 11a Reunion de la Red Espanola de Bacterias Lacticas (RedBAL), celebrada en Gijon (Asturias, Espana) del 28 al 30 de Junio de 2017Trabajo Fin de Master: Master en Catalisis Homogenea y Quimica Molecular. Grupo de Cristales liquidos y Polimeros, Departamento de Quimica Organica de la Universidad de Zaragoza (Curso 2014/2015).La elaboracion de este articulo se inscribe en el proyecto de investigacion “Innovacion oculta: cambio de paradigma en los estudios de innovacion” (FFI2011-25475), Ministerio de Economia y Competitividad, Gobierno de Espana.Poster presented at the 18th International Microscopy Congress (ICM 2014) that took place in Prague (Czech Republic) during 7-12th September 2014.Esta investigacion ha sido posible gracias a la financiacion de los proyectos del Plan Nacional CGL2012-36682 y CGL2016-75109-P del Ministerio de Economia y Competitividad, y al Convenio Principado de Asturias-Universidad de Oviedo y MNCN-CSIC.Resumen del poster presentado a la 10th International Conference one Carbon Metabolism, vitamins B and Homocysteine, celebrada en Nancy (Francia) del 7 al 11 de julio de 2015.La celulosa es la fuente de energia mas abundante que hay en la Tierra. Su transformacion en glucosa se considera la etapa mas importante en la produccion de biocombustibles a partir de biomasa lignocelulosica. Para esta transformacion es necesaria la accion sinergica de tres tipos de enzimas que hidrolizan los enlaces s-1,4 de la celulosa: (i) las endoglucanasas, que actuan al azar sobre enlaces internos, (ii) las celobiohidrolasas, que operan progresivamente por los extremos reductores y no reductores de la cadena, y (iii) las s-glucosidasas (BGL), que hidrolizan celobiosa y los celooligosacaridos mas pequenos hasta glucosa. Los hongos filamentosos son la principal fuente de celulasas, siendo los crudos del genero Trichoderma los mas estudiados y comercializados historicamente. Sin embargo, estos hongos secretan niveles insuficientes de BGL para una conversion efectiva de la celulosa, por lo que con frecuencia requieren ser suplementados con preparaciones ricas en esta enzima procedentes de otros hongos. Recientemente, se han descrito cepas de Penicillium con gran capacidad para secretar altos niveles de BGL al medio extracelular. Ademas de su papel en la hidrolisis de la celulosa las BGL tambien pueden emplearse para sintetizar compuestos de interes industrial mediante reacciones de transglicosilacion. En este trabajo se ha estudiado una nueva cepa fungica productora de celulasas, identificada como Talaromyces amestolkiae, en base a un analisis molecular y morfologico. Se han purificado a homogeneidad electroforetica tres BGL (BGL-1, BGL-2 y BGL-3) secretadas por el hongo y se han caracterizado bioquimicamente. BGL-1 y BGL-2 son proteinas monomericas, mientras que BGL-3 es un dimero funcional. Los valores de actividad maxima de estas enzimas se obtuvieron a pH 4,0 y entre 50-60 oC, siendo estables en un rango de pH de 4-7 y a 50 oC. Las tres mostraron distinto comportamiento en funcion del sustrato (pNPG o celobiosa), ensayandose tambien el efecto de determinados compuestos quimicos e inhibidores en su actividad. Las tres pueden hidrolizar celooligosacaridos de diferente longitud, disminuyendo la eficacia de hidrolisis con el aumento de la polimerizacion, y no son activas frente a polisacaridos. Ademas, mostraron actividad de transglicosilacion, formando alquilglicosidos y celooligosacaridos de mayor longitud que los usados como sustratos. Las tres BGL se identificaron mediante huella peptidica y en base la alta homologia con otras BGL fungicas relacionadas filogeneticamente, se disenaron cebadores especificos que permitieron la secuenciacion de los genes que codifican cada una de ellas. El analisis de las secuencias aminoacidicas mostro que BGL-1 es miembro de la familia 1 de las glicosil hidrolasas, mientras que BGL-2 y BGL-3 pertenecen a la familia 3. Teniendo en cuenta que existen pocas BGL fungicas cristalizadas, se construyeron modelos moleculares de estas ultimas en base a las estructuras con las que presentaron mayor identidad. El crudo enzimatico de T. amestolkiae, rico en BGL, se uso de forma individual y como suplemento de otros cocteles comerciales en experimentos de sacarificacion a partir de slurry acido de paja de trigo. Los resultados obtenidos indican que el hongo secreta, ademas de celulasas, otras enzimas complementarias que potencian la liberacion de azucares fermentables. Se analizo el secretoma de T. amestolkiae usando Avicel o slurry acido de paja de trigo como fuente de carbono. Las celulasas fueron las enzimas mas abundantes en ambas condiciones, sin embargo, en el crudo obtenido a partir de los cultivos en slurry aumento la proporcion de BGL y otras enzimas distintas a las celulasas, indicando que para la degradacion de un sustrato complejo es necesaria mayor diversidad enzimatica. Los resultados obtenidos en este trabajo abren nuevas vias para la formulacion de cocteles enzimaticos eficaces en el contexto de la degradacion de la biomasa lignocelulosica.Trabajo presentado en el 4th International Congress on Ichnology - ICHNIA 2016: Ichnology for the 21st century: (Palaeo) Biological Traces towards Sustainable Development, celebrado en Idanha-a-Nova (Portugal), del 6 al 9 de mayo de 2016Resumen del trabajo presentado al Joint European Magnetic Symposia (JEMS), celebrado en Glasgow (UK) del 21 al 26 de agosto de 2016.Vazquez, J. T. ... et. al.-- Inciativa Iberica para el Estudio de las Fallas Activas, Tercera Reunion Iberica sobre Fallas Activas y Paleosismologia IBERFAULT 2018 - Third Iberian Meeting on Active Faults and Paleoseismology, 11-13 June 2018, Alicante, Spain.-- 4 pages, 2 figuresLa infeccion temprana por Verticillium dahliae en olivar y la discriminacion entre niveles de severidad de la Verticilosis es viable mediante la utilizacion de imagenes termicas, multiespectrales e hiperespectrales adquiridas con vehiculos aereos no tripulados a escala de parcela o tripulados a escala de comarca. El indicador relacionado con la temperatura de copa (CWSI), indices de reflectancia (B, BG1, BR1) y la fluorescencia clorofilica (FLD3) se identifican como buenos indicadores para detectar la Verticilosis en etapas tempranas del desarrollo de la enfermedad, mientras que NDVI, PRI515, R/G, HI e indices de estimacion de clorofila y carotenos demuestran ser buenos indicadores para la cuantificacion de dano moderado o severo causada por Verticilosis, lo que puede ser de utilidad para el diseno de estrategias de control de la Verticilosis a escala de parcela y de comarca. La infeccion temprana por Verticillium dahliae en olivar y la discriminacion entre niveles de severidad de la Verticilosis es viable mediante la utilizacion de imagenes termicas, multiespectrales e hiperespectrales adquiridas con vehiculos aereos no tripulados a escala de parcela o tripulados a escala de comarca. El indicador relacionado con la temperatura de copa (CWSI), indices de reflectancia (B, BG1, BR1) y la fluorescencia clorofilica (FLD3) se identifican como buenos indicadores para detectar la Verticilosis en etapas tempranas del desarrollo de la enfermedad, mientras que NDVI, PRI515, R/G, HI e indices de estimacion de clorofila y carotenos demuestran ser buenos indicadores para la cuantificacion de dano moderado o severo causada por Verticilosis, lo que puede ser de utilidad para el diseno de estrategias de control de la Verticilosis a escala de parcela y de comarca. El olivo (Olea europaea L.) es el cultivo lenoso no tropical que ocupa mayor superficie en todo el mundo, con el 95% de la produccion mundial localizada en la cuenca mediterranea. Espana es el pais con mayor superficie de olivar del mundo con 2,6 MHa y aproximadamente el 39% de la produccion mundial. La Verticilosis, causada por el hongo de suelo Verticillium dahliae Kleb, constituye la principal amenaza para el olivar. Esta enfermedad afecta al olivo en todos los paises de tradicion olivarera y causa importantes perdidas de rendimiento y muerte de los arboles (Jimenez-Diaz y col., 2012). Este patogeno coloniza el sistema vascular de la planta, bloqueando el flujo del agua y finalmente induciendo estres hidrico (Van Alfen, 1989).Espana es el mayor productor de citricos de la Union Europea y el quinto a nivel mundial, con una produccion anual superior a cinco millones de toneladas (MAGRAMA, 2016). Este sector genera una gran cantidad de subproductos, con un elevado aporte energetico y alto contenido en pectinas y azucares, por lo que podrian usarse como materias primas en dietas para rumiantes. Sin embargo, los subproductos de citricos son muy diversos, por lo que su composicion quimica y valor nutritivo tambien puede ser variable (FEDNA, 2010; Feedipedia, 2016). El objetivo de este trabajo fue analizar la composicion quimica y la produccion de gas in vitro de subproductos de citricos producidos en nuestro pais.Resumen del trabajo presentado a las I Jornadas Cientificas del CIAL celebradas el 5 de junio de 2014 en Madrid.The Indian Summer Monsoon onset is one of the meteorological events most anticipated in the world. Due to its relevance for the population, the India Meteorological Department has dated the onset over the southern tip of the Indian Peninsula (Kerala) since 1901. The traditional method to date the onset was based in the judgment of skilled meteorologist and because of this, the method was considered subjective and not adequate for the study of long-term changes in the onset.Resumen del poster presentado a las I Jornadas Cientificas del CIAL celebradas el 5 de junio de 2014 en Madrid.Trabajo presentado en el European Workshop on Experimental and Behavioral Economics (EWEBE), organizado por la Universidad de Bologna los dias 26 y 27 de mayo de 2017 con el titulo: The impact of deliberative structures on voting behavio.--Trabajo presentado en los Bilkent Microeconomics Seminars organizados por la Bilkent University (Ankara, Turkey) el dia 29 de noviembre de 2017La compacidad del racimo es un rasgo de gran interes en la vid, dado que puede condicionar su calidad y rendimiento. Estos efectos se producen fundamentalmente a traves de su relacion, directa o indirecta, con la arquitectura del racimo, el comportamiento reproductivo y el grado o modo de exposicion de las bayas al ambiente. Respecto a los dos primeros, en un estudio previo, determinamos que tanto la longitud del raquis y sus primeras ramas como el numero de bayas por racimo son los caracteres con mayor incidencia en la compacidad entre los analizados. Ahora bien, el estudio de la base genetica responsable del numero de bayas requiere de su diseccion previa, dado que es una variable secundaria, resultado del numero de flores por inflorescencia y de la tasa de cuajado o conversion de flor en fruto. En este trabajo se presenta un estudio preliminar en el que se han caracterizado fenotipicamente 104 variedades de vid para estudiar su comportamiento reproductivo. Asi, sobre una base amplia de diversidad varietal, se han estimado variables como el numero de flores, la tasa de cuajado, corrimiento, millerandage, etc., evaluando su posible relacion con la compacidad del racimo. Este trabajo, una vez completado durante varios anos, permitira conocer la diversidad existente para el comportamiento reproductivo en la vid, asi como, de forma mas concreta, abordar la caracterizacion de los procesos geneticos responsables de las diferencias fenotipicas detectadas para el comportamiento reproductivo y sus elementos individuales y para la compacidad del racimo, identificando los posibles genes involucrados en dichos procesos.Trabajo presentado en la 11th International Conference on Grapevine Breeding and Genetics, celebrada en Pekin del 29 de julio al 2 de agosto de 2014.The Polarimetric and Helioseismic Imager (PHI) is the first deep-space solar spectropolarimeter, on-board the Solar Orbiter (SO) space mission. It faces: stringent requirements on science data accuracy, a dynamic environment, and severe limitations on telemetry volume. SO/PHI overcomes these restrictions through on-board instrument calibration and science data reduction, using dedicated firmware in FPGAs. This contribution analyses the accuracy of a data processing pipeline by comparing the results obtained with SO/PHI hardware to a reference from a ground computer. The results show that for the analysed pipeline the error introduced by the firmware implementation is well below the requirements of SO/PHI.This work has been financed within the framework of the projects P/309307 Arqueoastronomia of the IAC, and Orientatio ad sidera III (AYA2011-26759) of the Spanish MINECO. ACGG is Ramon y Cajal researcher of the MINECO.Este trabajo ha sido financiado por el proyecto RECUPERA 2020 del MINECO y EU-FEDER; y por el proyecto TRANS·FORMA (PP.TRA.TAA201600.9). La investigacion realizada por E. Rodriguez ha sido realizada gracias al programa DOC-INIA (INIA-FEDER).Trabajo presentado en el XXIV Congreso Iberoamericano de Catalisis (CICat 2014), “Catalisis para Biorrefineria”, celebrado en Medellin del 11 al 13 de septiembre de 2014.2 paginas y 1 tabla.- Trabajo presentado en el IX Congreso de Mejora Genetica de Plantas celebrado en Murcia entre el 18 y el 20 de septiembre de 2018.3 paginas, 1 tabla, 1 figura.--Trabajo presentado a las XVI Jornadas sobre Produccion Animal AIDA (Zaragoza, 19 al 20 de mayo, 2015).Poster presentado en el XVI International Clay Conference from the Oceans to Space Granada, Spain, July 17-21, (2017)XIII Reunion Iberica de Algas Toxicas y Biotoxinas Marinas (REDIBAL 2018) - XIII Reunion Iberica de Fitoplancton Toxico - XIII Iberian Toxic Algae and Marine Biotoxins Meeting, VI Simposio Internacional de Ciencias del Mar - VI International Symposium of Marine Sciences (ISMS 2018), 20- 22 June 2018, Vigo.-- 2 pagesThis research was financed with project AGL2011-22783 granted by the Spanish Ministry of Economy and Competiveness. M.C. Soto was supported by a CONACYT (Mexican Council of Sciences and Technology) doctoral fellowship.This work was supported by the Spanish Ministerio de Economia y Competitividad (grants CGL2012-36251 and CGL2015-64727-P to X.B., and BFU2010-15906 to JLM), and Catalan Government (2014 SGR 619). The research has also benefited from FEDER funds.Trabajo presentado en el IX International Symposium on Grapevine Physiology and Biotechnology, celebrado en La Serena (Chile) del 21 al 26 de abril de 2013.5 paginas, 4 figuras, 1 tabla.--Trabajo presentado a las: XLI Jornadas Cientificas y XVII Jornadas Internacionales de Ovinotecnia y Caprinotecnia. (Talavera de la Reina, Toledo, Espana, 14-16 septiembre, 2016).Se presenta una revisión histórica de los equinodermos Ordovícicos de Portugal. Todos los registros conocidos hasta el momento pertenecen al Ordovícico Medio-Superior (Darriwiliense-Katiense) y las asociaciones presentan gran diversidad aunque en general los taxones están poco o mal conocidos. La mayor parte de los yacimientos se concentran en las regiones de Amêndoa-Mação y Buçaco, aunque también existen citas de equinodermos en Arouca, Dornes, Moncorvo y Valongo. Por último se comentan futuras líneas de trabajo que ayudarán a comprender mejor estas faunas, perfeccionar y completar el conocimiento del registro fósil del grupo en el Ordovícico centroibérico. Ordovician echinoderms from Portugal: state of the artResumen del trabajo presentado al 37o Convegno Internazionale dei Docenti della Rappresentazione de la Unione Italiana Disegno (UDI), celebrado en Torino (Italia) del 17 al 19 de septiembre de 2015.Trabajo presentado al Danish Days on Caloric Materials and Devices, celebrado en Roskilde (Dinamarca) del 2 al 3 de octubre de 2017.Trabajo presentado en el ImageNano 2015 (Bringing together Nanoscience and Nanotechnology), celebrado en Bilbao del 10 al 13 de marzo de 2015.Este estudio ha sido financiado por el proyecto AGL-2012-40172-C02-01 del Ministerio de Economia y Competitividad (MINECO). AEF agradece al MINECO la financiacion de su contrato de investigacion (FPI).We present a detailed study of a X -ray selected sample of 5 submillimeter bright QSOs at

Collaboration


Dive into the Marta Vergara-Irigaray's collaboration.

Top Co-Authors

Avatar

Iñigo Lasa

Universidad Pública de Navarra

View shared research outputs
Top Co-Authors

Avatar

Alejandro Toledo-Arana

Universidad Pública de Navarra

View shared research outputs
Top Co-Authors

Avatar

Igor Ruiz de los Mozos

Universidad Pública de Navarra

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Maite Villanueva

Spanish National Research Council

View shared research outputs
Top Co-Authors

Avatar

Begoña García

Spanish National Research Council

View shared research outputs
Top Co-Authors

Avatar

Nekane Merino

Universidad Pública de Navarra

View shared research outputs
Top Co-Authors

Avatar

Cristina Solano

Universidad Pública de Navarra

View shared research outputs
Top Co-Authors

Avatar

Jaione Valle

Universidad Pública de Navarra

View shared research outputs
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge