Determination of Soluble Sugars in Arabidopsis thaliana Leaves by Anion Exchange Chromatography

Determination of soluble sugars is basic for the study of carbon metabolism in plants. Soluble sugar quantitation can be achieved by enzymatic methods implying different coupled reactions. Here we describe a simple method that allows rapid determination of the most abundant soluble sugars (glucose, fructose and sucrose) in Arabidopsis leaves by anion exchange chromatography. We have applied this method to study the levels of soluble sugars during the photoperiodic transition to flowering (Ortiz-Marchena et al., 2014).España, MINECO projects CSD2007-00057, BIO2008-02292, and BIO2011-28847-C02-00España, Junta de Andalucía P06-CVI-01450 and P08-AGR-0358

Purification of Starch Granules from Arabidopsis Leaves and Determination of Granule-Bound Starch Synthase Activity

Starch constitutes the most important carbon reserve in plants and is composed of branched amylopectin and linear amylose. The latter is synthesized exclusively by the Granule-Bound Starch Synthase (GBSS, EC 2.4.1.21). Here we report a readily reproducible, specific and highly sensitive protocol, which includes the isolation of intact starch granules from Arabidopsis thaliana leaves and the subsequent determination of GBSS activity. We have applied this method to study GBSS activity in diurnal cycles in vegetative growth and during the photoperiodic transition to flowering in Arabidopsis (Tenorio et al., 2003; Ortiz-Marchena et al., 2014).España,MINECO CSD2007-00057, BIO2008-02292, and BIO2011-28847-C02-00España, Junta de Andalucía P06-CVI-01450 and P08-AGR-0358

Miniaturised and harmonic-suppressed rat-race couplers based on slow-wave transmission lines

Altres ajuts: JANDALUCIA/P12-TIC-1435In this study, a compact rat-race hybrid coupler with harmonic suppression based on slow-wave transmission lines (SW-TLs) is presented. Such artificial lines are implemented by periodic loading a host microstrip line with series meandered inductors and shunt patch capacitors. The presence of both loading elements has a twofold effect, i.e. phase velocity reduction (due to the enhancement of the effective inductance and capacitance of the periodic line), and the generation of a controllable stopband in the frequency response (due to the Bragg effect, inherent to periodicity). It is shown that by designing the unit cell of the periodic line with an electrical length of 45°, at least the first five harmonic bands of the rat-race coupler are efficiently suppressed, keeping the band of interest unaltered. Moreover, 79% size reduction, as compared to the ordinary coupler, is achieved in the reported SW-TL-based prototyp

On the vulnerability of iris-based systems to a software attack based on a genetic algorithm

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-33275-3_14Proceedings of 17th Iberoamerican Congress, CIARP 2012, Buenos Aires, ArgentinaThe vulnerabilities of a standard iris verification system to a novel indirect attack based on a binary genetic algorithm are studied. The experiments are carried out on the iris subcorpus of the publicly available BioSecure DB. The attack has shown a remarkable performance, thus proving the lack of robustness of the tested system to this type of threat. Furthermore, the consistency of the bits of the iris code is analysed, and a second working scenario discarding the fragile bits is then tested as a possible countermeasure against the proposed attack.This work has been partially supported by projects Contexts (S2009/TIC-1485) from CAM, Bio-Challenge (TEC2009-11186) from Spanish MICINN, TABULA RASA (FP7-ICT-257289) and BEAT (FP7-SEC-284989) from EU, and Cátedra UAM-Telefónica

Characterization of the sucrose phosphate phosphatase (SPP) isoforms from Arabidopsis thaliana and role of the S6PPc domain in dimerization

Sucrose-phosphate phosphatase (SPP) catalyses the final step in the sucrose biosynthesis pathway. Arabidopsis thaliana genome codifies four SPP isoforms. In this study, the four Arabidopsis thaliana genes coding for SPP isoforms have been cloned, expressed in Escherichia coli and the kinetic and regulatory properties of the purified enzymes analysed. SPP2 is the isoform showing the highest activity, with SPP3b and SPP3a showing lower activity levels. No activity was detected for SPP1. We propose that this lack of activity is probably due to the absence of an essential amino acid participating in catalysis and/or in the binding of the substrate, sucrose-6-phosphate (Suc6P). The expression patterns of Arabidopsis SPP genes indicate that SPP2 and SPP3b are the main isoforms expressed in different tissues and organs, although the non-catalytic SPP1 is the main isoform expressed in roots. Thus, SPP1 could have acquired new unknown functions. We also show that the three catalytically active SPPs from Arabidopsis are dimers. By generating a chimeric SPP composed of the monomeric cyanobacterial SPP fused to the higher plant non-catalytic S6PPc domain (from SPP2), we show that the S6PPc domain is responsible for SPP dimerization. This is the first experimental study on the functionality and gene expression pattern of all the SPPs from a single plant species.Ministerio de Economía y Competitividad TRANSPLANTA Consolider 28317Junta de Andalucía P08-AGR-03582 y CVI-28

¿Cómo identifican las oportunidades de negocio los emprendedores? Una aproximación descriptiva al caso andaluz.

Este trabajo pretende contribuir al estudio de los factores y características que influyen en el proceso emprendedor, concretamente en la fase de identificación de oportunidades emprendedoras, previa a las de evaluación y explotación. En el estudio se ha analizado una muestra de 241 empresarios andaluces que han puesto en marcha una o más oportunidades. Mediante un análisis descriptivo se determinan el papel que juegan en el descubrimiento de oportunidades los factores relativos a las características del emprendedor y motivaciones, su capital humano, con especial atención al conocimiento previo, así como las principales fuentes para su identificación. The purpose of this paper is to contribute to the study of the factors and characteristics that may influence the entrepreneurial process, focusing specifically on the identification of entrepreneurial opportunities. Our study analyzes a sample of 241 Andalusian entrepreneurs that have driven one or several entrepreneurial opportunities. The results of the descriptive analysis show the role that entrepreneur’s characteristics, motivation, human capital (specially prior knowledge), and the sources for opportunity identification play in the discovery of new opportunities.Emprendedor, Proceso Emprendedor, Oportunidad, Identificación,Conocimiento Previo entrepreneur, entrepreneurial process, opportunity, identification, prior knowledge.

CAX1a TILLING Mutations Modify the Hormonal Balance Controlling Growth and Ion Homeostasis in Brassica rapa Plants Subjected to Salinity

Salinity is a serious issue for crops, as it causes remarkable yield losses. The accumulation of Na+ a ects plant physiology and produces nutrient imbalances. Plants trigger signaling cascades in response to stresses in which phytohormones and Ca2+ are key components. Cation/H+ exchangers (CAXs) transporters are involved in Ca2+ fluxes in cells. Thus, enhanced CAX activity could improve tolerance to salinity stress. Using the TILLING (targeting induced local lesions in genomes) technique, three Brassica rapa mutants were generated through a single amino acidic modification in the CAX1a transporter. We hypothesized that BraA.cax1a mutations could modify the hormonal balance, leading to improved salinity tolerance. To test this hypothesis, the mutants and the parental line R-o-18 were grown under saline conditions (150 mM NaCl), and leaf and root biomass, ion concentrations, and phytohormone profile were analyzed. Under saline conditions, BraA.cax1a-4 mutant plants increased growth compared to the parental line, which was associated with reduced Na+ accumulation. Further, it increased K+ concentration and changed the hormonal balance. Specifically, our results show that higher indole-3-acetic acid (IAA) and gibberellin (GA) concentrations in mutant plants could promote growth under saline conditions, while abscisic acid (ABA), ethylene, and jasmonic acid (JA) led to better signaling stress responses and water use e ciency. Therefore, CAX1 mutations directly influence the hormonal balance of the plant controlling growth and ion homeostasis under salinity. Thus, Ca2+ signaling manipulation can be used as a strategy to improve salinity tolerance in breeding programs.PAI program (Plan Andaluz de Investigación, Grupo de Investigación) AGR282National Health and Medical Research Council of Australia German Research Foundation (DFG) FPU14/0185

Exploring the use of recombinant inbred lines in combination with beneficial microbial inoculants (AM fungus and PGPR) to improve drought stress tolerance in tomato

At a world scale, tomato is an important horticultural crop, but its productivity is highly reduced by drought stress. Combining the application of beneficial microbial inoculants with breeding and grafting techniques may be key to cope with reduced tomato yield under drought. This study aimed to investigate the growth responses and physiological mechanisms involved in the performance under drought stress of four tomato recombinant inbred lines (RIL) after inoculation with the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis and the plant growth promoting rhizobacteria (PGPR) Variovorax paradoxus 5C-2. Results showed a variation in the efficiency of the different tomato RILs under drought stress and a differential effect of the microbial inoculants, depending on the RIL involved. The inoculants affected plant parameters such as net photosynthetic capacity, oxidative damage to lipids, osmolyte accumulation, root hydraulic conductivity or aquaporin abundance and phosphorylation status. RIL66 was the one obtaining maximum benefit from the microbial inoculants under drought stress conditions, due likely to improved CO2-fixation capacity and root hydraulic conductivity. We propose that RIL66 could be selected as a good plant material to be used as rootstock to improve tomato growth and productivity under water limiting conditions. Since RIL66 is highly responsive to microbial inoculants, this grafting strategy should be combined with inoculation of R. irregularis and V. paradoxus in order to improve plant yield under conditions of drought stress

Quién soy, qué conozco y a quién conozco: el uso de la lógica de efectuación por los emprendedores académicos

ABSTRACT The logic of effectuation argues that entrepreneurs create their businesses through a process of repeated action that is creative and unplanned, utterly contrary to causal logic or to the rational process put forward in the literature on entrepreneurship. In this study we focus on the use of effectual logic by academic entrepreneurs, i.e, university teachers or researchers who have founded a (research-knowledge based) university spin-off. Our research aims to analyze whether academic entrepreneurs engage in effectual behaviors in the process of creation and development of spinoffs. We analyze 16 cases of academic entrepreneurs from Spanish universities to obtain evidence of their effectual behavior. This study contributes to achieve a greater comprehension about how academic entrepreneurs transform their knowledge, experience, and the resources available in entrepreneurial opportunities. It also helps us better understand how different factors in the university context influence the practice of effectuation.La lógica de la efectuación argumenta que los emprendedores crean sus empresas siguiendo un proceso de acción reiterada, creativo y no planificado, totalmente contrario a la lógica de causalidad o al proceso racional propuesto en la literatura sobre el emprendimiento.  En este estudio nos centramos en el uso de la lógica de efectuación por los emprendedores académicos, es decir, profesores universitarios o investigadores que han fundado una spin-off basada en resultados de investigación. El objetivo de nuestro trabajo es analizar en qué medida los emprendedores académicos desarrollan una acción emprendedora basada en la lógica de efectuación o causalidad y cómo los factores propios del contexto universitario influyen en el uso de las mencionadas lógicas. Analizamos un total de 16 casos de emprendedores académicos de las universidades españolas para obtener evidencia de su comportamiento emprendedor. Este estudio contribuye a lograr una mayor comprensión sobre cómo los emprendedores académicos usan sus conocimientos, experiencia empresarial y recursos disponibles en la configuración de oportunidades emprendedoras. También aporta una mejor comprensión sobre cómo los diferentes factores en el contexto universitario influyen en la práctica de la efectuación. ABSTRACT The logic of effectuation argues that entrepreneurs create their businesses through a process of repeated action that is creative and unplanned, utterly contrary to causal logic or to the rational process put forward in the literature on entrepreneurship. In this study we focus on the use of effectual logic by academic entrepreneurs, i.e, university teachers or researchers who have founded a (research-knowledge based) university spin-off. Our research aims to analyze whether academic entrepreneurs engage in effectual behaviors in the process of creation and development of spinoffs. We analyze 16 cases of academic entrepreneurs from Spanish universities to obtain evidence of their effectual behavior. This study contributes to achieve a greater comprehension about how academic entrepreneurs transform their knowledge, experience, and the resources available in entrepreneurial opportunities. It also helps us better understand how different factors in the university context influence the practice of effectuation