Network


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

Hotspot


Dive into the research topics where Tobias Maierhofer is active.

Publication


Featured researches published by Tobias Maierhofer.


Science Signaling | 2011

Stomatal Closure by Fast Abscisic Acid Signaling Is Mediated by the Guard Cell Anion Channel SLAH3 and the Receptor RCAR1

Dietmar Geiger; Tobias Maierhofer; Khaled A. S. Al-Rasheid; Sönke Scherzer; Patrick Mumm; Anja Liese; Peter Ache; Christian Wellmann; Irene Marten; Erwin Grill; Tina Romeis; Rainer Hedrich

Plant survival during periods of drought may involve SLAH3, a nitrate-conducting anion channel activated by abscisic acid. Conducting Closure Stomata are pores in the plant epidermis that allow the movement of CO2 into the plant concomitant with the loss of water. The opening and closing of these pores is mediated by the surrounding guard cells, which respond to drought, nutrient availability, and the plant stress hormone abscisic acid (ABA). Geiger et al. identified the anion channel SLAH3 as a player in the guard cell pathway downstream of ABA and defined its mode of regulation through an ABA receptor–phosphatase RCAR1-ABI complex and a calcium-dependent kinase, CPK21. Unlike previously characterized anion channels that are regulated by ABA and contribute to stomatal closure, activation of SLAH3 was promoted by nitrate and was 20 times as permeable to nitrate ions as to chloride ions. Thus, SLAH3 may integrate nitrate signaling and metabolism with signals initiated by drought conditions to control respiration and water loss. S-type anion channels are direct targets of abscisic acid (ABA) signaling and contribute to chloride and nitrate release from guard cells, which in turn initiates stomatal closure. SLAC1 was the first component of the guard cell S-type anion channel identified. However, we found that guard cells of Arabidopsis SLAC1 mutants exhibited nitrate conductance. SLAH3 (SLAC1 homolog 3) was also present in guard cells, and coexpression of SLAH3 with the calcium ion (Ca2+)–dependent kinase CPK21 in Xenopus oocytes mediated nitrate-induced anion currents. Nitrate, calcium, and phosphorylation regulated SLAH3 activity. CPK21-dependent SLAH3 phosphorylation and activation were blocked by ABI1, a PP2C-type protein phosphatase that is inhibited by ABA and inhibits the ABA signaling pathway in guard cells. We reconstituted the ABA-stimulated phosphorylation of the SLAH3 amino-terminal domain by CPK21 in vitro by including the ABA receptor–phosphatase complex RCAR1-ABI1 in the reactions. We propose that ABA perception by the complex consisting of ABA receptors of the RCAR/PYR/PYL family and ABI1 releases CPK21 from inhibition by ABI1, and then CPK21 is further activated by an increase in the cytosolic Ca2+ concentration, leading to its phosphorylation of SLAH3. Thus, the identification of SLAH3 as the nitrate-, calcium-, and ABA-sensitive guard cell anion channel provides insights into the relationship among stomatal response to drought, signaling by nitrate, and nitrate metabolism.


Science Signaling | 2014

Site- and kinase-specific phosphorylation-mediated activation of SLAC1, a guard cell anion channel stimulated by abscisic acid.

Tobias Maierhofer; Marion Diekmann; Jan Niklas Offenborn; Christof Lind; Hubert Bauer; Kenji Hashimoto; Khaled A. S. Al-Rasheid; Sheng Luan; Jörg Kudla; Dietmar Geiger; Rainer Hedrich

Kinases from three different families can activate an anion channel that helps plants tolerate drought stress. Three-in-One Drought Response One way that plants survive drought conditions is by closing gas exchange pores called stomata. Drought stimulates production of the hormone abscisic acid, which stimulates the opening of anion channels to reduce the volume of guard cells so that they come together and the stomata close. Maierhofer et al. expressed various kinases and their interacting partners in Xenopus oocytes along with the anion channels SLAC1 or SLAH3 and determined that in addition to the known two types of kinases that activated these channels, a third type of kinase also stimulated channel opening. The kinases belonged to both calcium-independent and calcium-dependent families and phosphorylated different residues on SLAC1. Future studies will address how this complex regulation enables plants to coordinate responses and adapt to stressful conditions. Under drought stress, abscisic acid (ABA) triggers closure of leaf cell pores called stomata, which are formed by two specialized cells called guard cells in plant epidermis. Two pathways downstream of ABA stimulate phosphorylation of the S-type anion channels SLAC1 (slow anion channel associated 1) and SLAH3 (SLAC1 homolog 3), which causes these channels to open, reducing guard cell volume and triggering stomatal closure. One branch involves OST1 (open stomata 1), a calcium-independent SnRK2-type kinase, and the other branch involves calcium-dependent protein kinases of the CPK (calcium-dependent protein kinase) family. We used coexpression analyses in Xenopus oocytes to show that the calcineurin B–like (CBL) calcium sensors CBL1 and CBL9 and their interacting protein kinase CIPK23 also triggered SLAC1 and SLAH3 opening. We analyzed whether regulation of SLAC1 opening by these different families of kinases involved the same or different sites on SLAC1 by measuring channel conductance of SLAC1 with mutations in the putative phosphorylation sites in the amino or carboxyl termini coexpressed with specific kinases in Xenopus oocytes. SLAC1 mutants lacking the OST1-phosphorylated site were still activated by CPK or by CBL/CIPK complexes. Phosphorylation and activation of SLAC1 by any of the kinases were inhibited by the phosphatase ABI1 (ABA insensitive 1), which is inactivated in response to ABA signaling. These findings identified CBL/CIPK complexes as potential regulators of stomatal aperture through S-type anion channels and indicated that phosphorylation at distinct sites enables SLAC1 activation by both calcium-dependent and calcium-independent pathways downstream of ABA.


The Plant Cell | 2013

Pollen Tube Growth Regulation by Free Anions Depends on the Interaction between the Anion Channel SLAH3 and Calcium-Dependent Protein Kinases CPK2 and CPK20

Timo Gutermuth; Roman Lassig; Maria-Teresa Portes; Tobias Maierhofer; Tina Romeis; Jan Willem Borst; Rainer Hedrich; José A. Feijó; Kai R. Konrad

Chloride and other anions are essential for cell volume regulation and other functions in plant cells. This study demonstrates the existence of an apical negative gradient of cytosolic chloride concentration in pollen tubes, and establishes a role for the SLAH3 homolog of SLOW ANION CHANNEL-ASSOCIATED 1, regulated by the calcium-dependent protein kinases CPK2 and CPK20, in regulating pollen tube apical growth. Apical growth in pollen tubes (PTs) is associated with the presence of tip-focused ion gradients and fluxes, implying polar localization or regulation of the underlying transporters. The molecular identity and regulation of anion transporters in PTs is unknown. Here we report a negative gradient of cytosolic anion concentration focused on the tip, in negative correlation with the cytosolic Ca2+ concentration. We hypothesized that a possible link between these two ions is based on the presence of Ca2+-dependent protein kinases (CPKs). We characterized anion channels and CPK transcripts in PTs and analyzed their localization. Yellow fluorescent protein (YFP) tagging of a homolog of SLOW ANION CHANNEL-ASSOCIATED1 (SLAH3:YFP) was widespread along PTs, but, in accordance with the anion efflux, CPK2/CPK20/CPK17/CPK34:YFP fluorescence was strictly localized at the tip plasma membrane. Expression of SLAH3 with either CPK2 or CPK20 (but not CPK17/CPK34) in Xenopus laevis oocytes elicited S-type anion channel currents. Interaction of SLAH3 with CPK2/CPK20 (but not CPK17/CPK34) was confirmed by Förster-resonance energy transfer fluorescence lifetime microscopy in Arabidopsis thaliana mesophyll protoplasts and bimolecular fluorescence complementation in living PTs. Compared with wild-type PTs, slah3-1 and slah3-2 as well as cpk2-1 cpk20-2 PTs had reduced anion currents. Double mutant cpk2-1 cpk20-2 and slah3-1 PTs had reduced extracellular anion fluxes at the tip. Our studies provide evidence for a Ca2+-dependent CPK2/CPK20 regulation of the anion channel SLAH3 to regulate PT growth.


The Plant Cell | 2014

A Single-Pore Residue Renders the Arabidopsis Root Anion Channel SLAH2 Highly Nitrate Selective

Tobias Maierhofer; Christof Lind; Stefanie Hüttl; Sönke Scherzer; Melanie Papenfuß; Judy Simon; Khaled A. S. Al-Rasheid; Peter Ache; Heinz Rennenberg; Rainer Hedrich; Thomas Müller; Dietmar Geiger

Here, SLAH2 was characterized as a nitrate-selective root anion channel in Arabidopsis. Comparison of SLAH2 with chloride and nitrate permeable SLAC1 by 3D-model-based mutagenesis approaches elucidated the molecular nature of the selectivity filter within the S-type anion channel family. In contrast to animal cells, plants use nitrate as a major source of nitrogen. Following the uptake of nitrate, this major macronutrient is fed into the vasculature for long-distance transport. The Arabidopsis thaliana shoot expresses the anion channel SLOW ANION CHANNEL1 (SLAC1) and its homolog SLAC1 HOMOLOGOUS3 (SLAH3), which prefer nitrate as substrate but cannot exclude chloride ions. By contrast, we identified SLAH2 as a nitrate-specific channel that is impermeable for chloride. To understand the molecular basis for nitrate selection in the SLAH2 channel, SLAC1 and SLAH2 were modeled to the structure of HiTehA, a distantly related bacterial member. Structure-guided site-directed mutations converted SLAC1 into a SLAH2-like nitrate-specific anion channel and vice versa. Our findings indicate that two pore-occluding phenylalanines constrict the pore. The selectivity filter of SLAC/SLAH anion channels is determined by the polarity of pore-lining residues located on alpha helix 3. Changing the polar character of a single amino acid side chain (Ser-228) to a nonpolar residue turned the nitrate-selective SLAH2 into a chloride/nitrate-permeable anion channel. Thus, the molecular basis of the anion specificity of SLAC/SLAH anion channels seems to be determined by the presence and constellation of polar side chains that act in concert with the two pore-occluding phenylalanines.


Current Biology | 2016

Silent S-Type Anion Channel Subunit SLAH1 Gates SLAH3 Open for Chloride Root-to-Shoot Translocation.

Paloma Cubero-Font; Tobias Maierhofer; Justyna Jaslan; Miguel A. Rosales; Joaquín Espartero; Pablo Díaz-Rueda; Heike M. Müller; Anna-Lena Hürter; Khaled A. S. Al-Rasheid; Irene Marten; Rainer Hedrich; José M. Colmenero-Flores; Dietmar Geiger

Higher plants take up nutrients via the roots and load them into xylem vessels for translocation to the shoot. After uptake, anions have to be channeled toward the root xylem vessels. Thereby, xylem parenchyma and pericycle cells control the anion composition of the root-shoot xylem sap [1-6]. The fact that salt-tolerant genotypes possess lower xylem-sap Cl(-) contents compared to salt-sensitive genotypes [7-10] indicates that membrane transport proteins at the sites of xylem loading contribute to plant salinity tolerance via selective chloride exclusion. However, the molecular mechanism of xylem loading that lies behind the balance between NO3(-) and Cl(-) loading remains largely unknown. Here we identify two root anion channels in Arabidopsis, SLAH1 and SLAH3, that control the shoot NO3(-)/Cl(-) ratio. The AtSLAH1 gene is expressed in the root xylem-pole pericycle, where it co-localizes with AtSLAH3. Under high soil salinity, AtSLAH1 expression markedly declined and the chloride content of the xylem sap in AtSLAH1 loss-of-function mutants was half of the wild-type level only. SLAH3 anion channels are not active per se but require extracellular nitrate and phosphorylation by calcium-dependent kinases (CPKs) [11-13]. When co-expressed in Xenopus oocytes, however, the electrically silent SLAH1 subunit gates SLAH3 open even in the absence of nitrate- and calcium-dependent kinases. Apparently, SLAH1/SLAH3 heteromerization facilitates SLAH3-mediated chloride efflux from pericycle cells into the root xylem vessels. Our results indicate that under salt stress, plants adjust the distribution of NO3(-) and Cl(-) between root and shoot via differential expression and assembly of SLAH1/SLAH3 anion channel subunits.


New Phytologist | 2016

SLAH3‐type anion channel expressed in poplar secretory epithelia operates in calcium kinase CPK‐autonomous manner

Mario Jaborsky; Tobias Maierhofer; Andrea Olbrich; María Escalante-Pérez; Heike M. Müller; Judy Simon; Elzbieta Krol; Tracey Ann Cuin; Jörg Fromm; Peter Ache; Dietmar Geiger; Rainer Hedrich

Extrafloral nectaries secrete a sweet sugar cocktail that lures predator insects for protection from foraging herbivores. Apart from sugars and amino acids, the nectar contains the anions chloride and nitrate. Recent studies with Populus have identified a type of nectary covered by apical bipolar epidermal cells, reminiscent of the secretory brush border epithelium in animals. Border epithelia operate transepithelial anion transport, which is required for membrane potential and/or osmotic adjustment of the secretory cells. In search of anion transporters expressed in extrafloral nectaries, we identified PttSLAH3 (Populus tremula × Populus tremuloides SLAC1 Homologue3), an anion channel of the SLAC/SLAH family. When expressed in Xenopus oocytes, PttSLAH3 displayed the features of a voltage-dependent anion channel, permeable to both nitrate and chloride. In contrast to the Arabidopsis SLAC/SLAH family members, the poplar isoform PttSLAH3 is independent of phosphorylation activation by protein kinases. To understand the basis for the autonomous activity of the poplar SLAH3, we generated and expressed chimera between kinase-independent PttSLAH3 and kinase-dependent Arabidopsis AtSLAH3. We identified the N-terminal tail and, to a lesser extent, the C-terminal tail as responsible for PttSLAH3 kinase-(in)dependent action. This feature of PttSLAH3 may provide the secretory cell with a channel probably controlling long-term nectar secretion.


Journal of Experimental Botany | 2018

Spatio-temporal aspects of Ca2+ signalling: lessons from guard cells and pollen tubes

Kai R. Konrad; Tobias Maierhofer; Rainer Hedrich

Changes in cytosolic Ca2+ concentration ([Ca2+]cyt) serve to transmit information in eukaryotic cells. The involvement of this second messenger in plant cell growth as well as osmotic- and water relations is well established. After almost 40 years of intense research on the coding and decoding of plant Ca2+ signals, numerous proteins involved in Ca2+ action have been identified. However, we are still far from understanding the complexity of Ca2+ networks. New in vivo Ca2+ imaging techniques combined with molecular genetics allow visualisation of spatio-temporal aspects of Ca2+ signalling. In parallel, cell biology together with protein biochemistry and electrophysiology are able to dissect information processing by this second messenger in space and time. Here we focus on the time-resolved changes in cellular events upon Ca2+ signals, concentrating on the two best-studied cell types, pollen tubes and guard cells. We put their signalling networks side by side, compare them with those of other cell types and discuss rapid signalling in the context of Ca2+ transients and oscillations to regulate ion homeostasis.


Current Biology | 2018

Understanding the Molecular Basis of Salt Sequestration in Epidermal Bladder Cells of Chenopodium quinoa

Jennifer Böhm; Maxim Messerer; Heike M. Müller; Joachim Scholz-Starke; Antonella Gradogna; Sönke Scherzer; Tobias Maierhofer; Nadia Bazihizina; Heng Zhang; Christian Stigloher; Peter Ache; Khaled A. S. Al-Rasheid; Klaus F. X. Mayer; Sergey Shabala; Armando Carpaneto; Georg Haberer; Jian-Kang Zhu; Rainer Hedrich

Soil salinity is destroying arable land and is considered to be one of the major threats to global food security in the 21st century. Therefore, the ability of naturally salt-tolerant halophyte plants to sequester large quantities of salt in external structures, such as epidermal bladder cells (EBCs), is of great interest. Using Chenopodium quinoa, a pseudo-cereal halophyte of great economic potential, we have shown previously that, upon removal of salt bladders, quinoa becomes salt sensitive. In this work, we analyzed the molecular mechanism underlying the unique salt dumping capabilities of bladder cells in quinoa. The transporters differentially expressed in the EBC transcriptome and functional electrophysiological testing of key EBC transporters in Xenopus oocytes revealed that loading of Na+ and Cl- into EBCs is mediated by a set of tailored plasma and vacuole membrane-based sodium-selective channel and chloride-permeable transporter.


The Plant Cell | 2018

The receptor-like pseudokinase GHR1 is required for stomatal closure

Maija Sierla; Hanna Hõrak; Kirk Overmyer; Cezary Waszczak; Dmitry Yarmolinsky; Tobias Maierhofer; Julia P. Vainonen; Konstantin Denessiouk; Jarkko Salojärvi; Kristiina Laanemets; Kadri Tõldsepp; Triin Vahisalu; Adrien Gauthier; Tuomas Puukko; Lars Paulin; Petri Auvinen; Dietmar Geiger; Rainer Hedrich; Hannes Kollist; Jaakko Kangasjärvi

GHR1 is a receptor-like pseudokinase that activates SLOW ANION CHANNEL1 and acts in stomatal closure through its scaffolding functions rather than by directly phosphorylating its target proteins. Guard cells control the aperture of stomatal pores to balance photosynthetic carbon dioxide uptake with evaporative water loss. Stomatal closure is triggered by several stimuli that initiate complex signaling networks to govern the activity of ion channels. Activation of SLOW ANION CHANNEL1 (SLAC1) is central to the process of stomatal closure and requires the leucine-rich repeat receptor-like kinase (LRR-RLK) GUARD CELL HYDROGEN PEROXIDE-RESISTANT1 (GHR1), among other signaling components. Here, based on functional analysis of nine Arabidopsis thaliana ghr1 mutant alleles identified in two independent forward-genetic ozone-sensitivity screens, we found that GHR1 is required for stomatal responses to apoplastic reactive oxygen species, abscisic acid, high CO2 concentrations, and diurnal light/dark transitions. Furthermore, we show that the amino acid residues of GHR1 involved in ATP binding are not required for stomatal closure in Arabidopsis or the activation of SLAC1 anion currents in Xenopus laevis oocytes and present supporting in silico and in vitro evidence suggesting that GHR1 is an inactive pseudokinase. Biochemical analyses suggested that GHR1-mediated activation of SLAC1 occurs via interacting proteins and that CALCIUM-DEPENDENT PROTEIN KINASE3 interacts with GHR1. We propose that GHR1 acts in stomatal closure as a scaffolding component.


Archive | 2016

Characterization of a root aninon channel that plays a pivotal role in plant chloride nutrition

Paloma Cubero Font; Joaquín Espartero; Tobias Maierhofer; Miguel Á. Rosales Villegas; Rainer Hedrich; P. Díaz-Rueda; Dietmar Geiger; José M. Colmenero Flores

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 Tobias Maierhofer's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Peter Ache

University of Würzburg

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Irene Marten

University of Würzburg

View shared research outputs
Top Co-Authors

Avatar

Judy Simon

University of Freiburg

View shared research outputs
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge