Dpto. Ciencias - Zientziak Saila [desde mayo 2018 / 2018ko maiatzetik]

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Now showing 1 - 20 of 518

Open Access
Silencing of hsa-miR-124 by EVI1 in cell lines and patients with acute myeloid leukemia
(National Academy of Sciences, 2010-01-07) Vázquez Urio, Iria; Maicas, Miren; Marcotegui, Nerea; Conchillo, Ana; Guruceaga, Elizabeth; Román-Gómez, José; Calasanz, María José; Agirre, Xabier; Prósper, Felipe; Odero, María D.; Ciencias; Zientziak
We read with great interest the work published by Dickstein et al. (1) showing that induced EVI1 expression in a murine model silences miR-124 expression by DNA methylation. The EVI1 gene codes for a transcription factor implicated in the development and progression of high-risk acute myeloid leukemia (AML) (2, 3). We quantify the expression of 250 microRNAs (miRNAs; TaqManHuman miRNA assay set) in 15 myeloid cell lines. Statistical analysis comparing cell lines with and without EVI1 protein identified miRNAs differentially expressed (B > 0)
Open Access
High irradiance induces photoprotective mechanisms and a positive effect on NH4+ stress in Pisum sativum L.
(Elsevier, 2010-04-29) Ariz Arnedo, Idoia; Esteban Terradillos, Raquel; García Plazaola, José Ignacio; Becerril, José María; Aparicio Tejo, Pedro María; Morán Juez, José Fernando; Ciencias; Zientziak; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
Photosynthesis provides plant metabolism with reduced carbon (C) but is also the main source of oxidative stress in plants. Likewise, high doses of NH4+ as sole N source have been reported to be toxic for most plants, resulting in reduced plant growth and restricting C availability. The combination of high photosynthetic photon flux densities (PPFD) and NH4+ nutrition may provide higher C availability but could also have a detrimental effect on the plants, therefore the objective of this study is to evaluate whether NH4+ induces photo-oxidative stress that is exacerbated under high light conditions. Pea plants (Pisum sativum cv. sugar-snap) were grown hydroponically with NH4+ (0.5, 2.5, 5 and 10 mM) under high (750 μmol photons m−2 s−1) or low PPFD conditions (350 μmol photons m−2 s−1). High PPFD contributes to a higher tolerance to ammonium by pea plants, as it originated higher biomass content due to higher photosynthetic rates. However, a deficit of N (0.5 and 2.5 mM NH4+) under high PPFD conditions caused an antioxidant response, as indicated by increased photoprotective pigment and chloroplastic superoxide dismutase contents. Plants grown with higher doses of N and high PPFD showed less need for photoprotection. An increase in the specific leaf weight (SLW) ratio was observed associated not only with high PPFDs but also with the highest NH4+ dose. Overall, these results demonstrate that, despite the activation of some photoprotective responses at high PPFD, there were no photoinhibitory symptoms and a positive effect on NH4+ toxicity, thus suggesting that the harmful effects of NH4+ are not directly related to the generation of photo-oxidative stress.
Open Access
EVI1 controls proliferation in acute myeloid leukaemia through modulation of miR-1-2
(Nature Publishing Group, 2010-09-14) Gómez-Benito, María; Conchillo, Ana; García, M. A.; Vázquez Urio, Iria; Maicas, Miren; Vicente, Carmen; Cristobal, I.; Marcotegui, Nerea; García-Ortí, L.; Bandrés Elizalde, Eva; Calasanz, María José ; Alonso, M. M.; Odero, María D.; Ciencias; Zientziak; Ciencias de la Salud; Osasun Zientziak; Gobierno de Navarra / Nafarroako Gobernua
Bakground: the EVI1(ecotropic virus integration site 1) gene codes for a zinc-finger transcription factor, whose transcriptional activation leads to a particularly aggressive form of acute myeloid leukaemia (AML). Although, EVI1 interactions with key proteins in hematopoiesis have been previously described, the precise role of this transcription factor in promoting leukaemic transformation is not completely understood. Recent works have identified specific microRNA (miRNA) signatures in different AML subgroups. However, there is no analysis of miRNAs profiles associated with EVI1 overexpression in humans. Methods: we performed QT-RT-PCR to assess the expression of 250 miRNAs in cell lines with or without EVI1 overexpression and in patient samples. We used ChIP assays to evaluated the possible binding of EVI1 binding to the putative miRNA promoter. Proliferation of the different cell lines transfected with the anti- or pre-miRs was quantified by MTT. Results: our data showed that EVI1 expression was significantly correlated with the expression of miR-1-2 and miR-133-a-1 in established cell lines and in patient samples. ChIP assays confirmed that EVI1 binds directly to the promoter of these two miRNAs. However, only miR-1-2 was involved in abnormal proliferation in EVI1 expressing cell lines. Conclusions: our data showed that EVI1 controls proliferation in AML through modulation of miR-1-2. This study contributes to further understand the transcriptional networks involving transcription factors and miRNAs in AML.
Open Access
Overexpression of GATA2 predicts an adverse prognosis for patients with acute myeloid leukemia and it is associated with distinct molecular abnormalities
(Springer Nature, 2012) Vicente, Carmen; Vázquez Urio, Iria; Conchillo, Ana; García-Sánchez, M. A.; Marcotegui, Nerea; Fuster, Óscar; González, Marcos; Calasanz, María José; Lahortiga, Idoya; Odero, María D.; Ciencias; Zientziak; © 2011 Springer Nature Limited.
Acute myeloid leukemia (AML) represents a heterogeneous group of hematological neoplasms associated with the accumulation of acquired genetic and epigenetic aberrations in hematopoietic progenitor cells. Myeloid leukemogenesis is directly linked to the disruption of expression of transcription factors that regulate the proliferation, survival and differentiation of myeloid progenitors. Moreover, overexpression of particular genes has been associated with prognosis in AML, enabling patients with different survival rates to be identified within cytogenetic risk groups. The GATA2 gene encodes a transcription factor that mediates essential functions in hematopoietic stem cell and progenitor cell (HSC/HPC) compartments. The essential role of GATA2 in hematopoiesis is evident in mice lacking GATA2, which are anemic, have fewer HSC/HPC cells and that die by day 10–11 of gestation.
Open Access
Functional characterization of the promoter region of the human EVI1 gene in acute myeloid leukemia: RUNX1 and ELK1 directly regulate its transcription
(Macmillan Press Ltd, 2012-06-11) Maicas, Miren; Vázquez Urio, Iria; Vicente, Carmen; García-Sánchez, M. A.; Marcotegui, Nerea; Urquiza, L.; Calasanz, María José; Odero, María D.; Ciencias; Zientziak; Gobierno de Navarra / Nafarroako Gobernua
The EVI1 gene (3q26) codes for a transcription factor with important roles in normal hematopoiesis and leukemogenesis. High expression of EVI1 is a negative prognostic indicator of survival in acute myeloid leukemia (AML) irrespective of the presence of 3q26 rearrangements. However, the only known mechanisms that lead to EVI1 overexpression are 3q aberrations, and the MLL-ENL oncoprotein, which activates the transcription of EVI1 in hematopoietic stem cells. Our aim was to characterize the functional promoter region of EVI1, and to identify transcription factors involved in the regulation of this gene. Generation of seven truncated constructs and luciferase reporter assays allowed us to determine a 318-bp region as the minimal promoter region of EVI1. Site-directed mutagenesis and chromatin immunoprecipitation (ChIP) assays identified RUNX1 and ELK1 as putative transcription factors of EVI1. Furthermore, knockdown of RUNX1 and ELK1 led to EVI1 downregulation, and their overexpression to upregulation of EVI1. Interestingly, in a series of patient samples with AML at diagnosis, we found a significant positive correlation between EVI1 and RUNX1 at protein level. Moreover, we identified one of the roles of RUNX1 in the activation of EVI1 during megakaryocytic differentiation. EVI1 knockdown significantly inhibited the expression of megakaryocytic markers after treating K562 cells with TPA, as happens when knocking down RUNX1. In conclusion, we define the minimal promoter region of EVI1 and demonstrate that RUNX1 and ELK1, two proteins with essential functions in hematopoiesis, regulate EVI1 in AML. Furthermore, our results show that one of the mechanisms by which RUNX1 regulates the transcription of EVI1 is by acetylation of the histone H3 on its promoter region. This study opens new directions to further understand the mechanisms of EVI1 overexpressing leukemias.
Open Access
Down-regulation of EVI1 is associated with epigenetic alterations and good prognosis in patients with acute myeloid leukemia
(Ferrata Storti Foundation, 2012-10-18) Vázquez Urio, Iria; Maicas, Miren; Cervera, José; Agirre, Xabier; Marin-Béjar, Oskar; Marcotegui, Nerea; Vicente, Carmen; Lahortiga, Idoya; Gómez-Benito, María; Carranza, Claudia; Valencia, Ana; Brunet, Salut; Lumbreras, Eva; Prósper, Felipe; Gómez-Casares, Teresa; Hernández-Rivas, Jesús M.; Calasanz, María José; Sanz, Miguel A.; Sierra, Jorge; Odero, María D.; Ciencias; Zientziak; Gobierno de Navarra / Nafarroako Gobernua
Background The EVI1 gene (3q26) codes for a zinc finger transcription factor with important roles in both mammalian development and leukemogenesis. Over-expression of EVI1 through either 3q26 rearrangements, MLL fusions, or other unknown mechanisms confers a poor prognosis in acute myeloid leukemia. Design and Methods We analyzed the prevalence and prognostic impact of EVI1 over-expression in a series of 476 patients with acute myeloid leukemia, and investigated the epigenetic modifications of the EVI1 locus which could be involved in the transcriptional regulation of this gene. Results Our data provide further evidence that EVI1 over-expression is a poor prognostic marker in acute myeloid leukemia patients less than 65 years old. Moreover, we found that patients with no basal expression of EVI1 had a better prognosis than patients with expression/over-expression (P=0.036). We also showed that cell lines with over-expression of EVI1 had no DNA methylation in the promoter region of the EVI1 locus, and had marks of active histone modifications: H3 and H4 acetylation, and trimethylation of histone H3 lysine 4. Conversely, cell lines with no expression of EVI1 have DNA hypermethylation and are marked by repressive trimethylation of histone H3 lysine 27 at the EVI1 promoter. Conclusions Our results identify EVI1 over-expression as a poor prognostic marker in a large, independent cohort of acute myeloid leukemia patients less than 65 years old, and show that the total absence of EVI1 expression has a prognostic impact on the outcome of such patients. Furthermore, we demonstrated for the first time that an aberrant epigenetic pattern involving DNA methylation, H3 and H4 acetylation, and trimethylation of histone H3 lysine 4 and histone H3 lysine 27 might play a role in the transcriptional regulation of EVI1 in acute myeloid leukemia. This study opens new avenues for a better understanding of the regulation of EVI1 expression at a transcriptional level.
Open Access
Loss of PPP2R2A inhibits homologous recombination DNA repair and predicts tumor sensitivity to PARP inhibition
(American Association for Cancer Research, 2012-10-18) Kalev, Peter; Simicek, Michal; Vázquez Urio, Iria; Munck, Sebastian; Chen, Liping; Soin, Thomas; Danda, Natasha; Chen, Wen; Sablina, Anna; Ciencias; Zientziak
Reversible phosphorylation plays a critical role in DNA repair. Here, we report the results of a loss-of-function screen that identifies the PP2A heterotrimeric serine/threonine phosphatases PPP2R2A, PPP2R2D, PPP2R5A, and PPP2R3C in double-strand break (DSB) repair. In particular, we found that PPP2R2A-containing complexes directly dephosphorylated ATM at S367, S1893, and S1981 to regulate its retention at DSB sites. Increased ATM phosphorylation triggered by PPP2R2A attenuation dramatically upregulated the activity of the downstream effector kinase CHK2, resulting in G1 to S-phase cell-cycle arrest and downregulation of BRCA1 and RAD51. In tumor cells, blocking PPP2R2A thereby impaired the high-fidelity homologous recombination repair pathway and sensitized cells to small-molecule inhibitors of PARP. We found that PPP2R2A was commonly downregulated in non-small cell lung carcinomas, suggesting that PPP2R2A status may serve as a marker to predict therapeutic efficacy to PARP inhibition. In summary, our results deepen understanding of the role of PP2A family phosphatases in DNA repair and suggest PPP2R2A as a marker for PARP inhibitor responses in clinic.
Open Access
p16/INK4a impairs homologous recombination-mediated DNA repair in human papillomavirus-positive head and neck tumors
(American Association for Cancer Research, 2014-01-28) Dok, Rüveyda; Kalev, Peter; Van Limbergen, Ever Jan; Asbagh, Layka Abbasi; Vázquez Urio, Iria; Hauben, Esther; Sablina, Anna; Nuyts, Sandra; Ciencias; Zientziak
The p16INK4a protein is a principal cyclin-dependent kinase inhibitor that decelerates the cell cycle. Abnormally high levels of p16INK4a are commonly observed in human papillomavirus (HPV)-positive head and neck squamous cell carcinomas (HNSCC). We and others found that p16INK4a overexpression is associated with improved therapy response and survival of patients with HNSCC treated with radiotherapy. However, the functional role of p16INK4a in HNSCC remains unexplored. Our results implicate p16INK4a in regulation of homologous recombination-mediated DNA damage response independently from its role in control of the cell cycle. We found that expression of p16INK4a dramatically affects radiation sensitivity of HNSCC cells. p16INK4a overexpression impairs the recruitment of RAD51 to the site of DNA damage in HPV-positive cells by downregulating of cyclin D1 protein expression. Consistent with the in vitro findings, immunostaining of HNSCC patient samples revealed that high levels p16INK4a expression significantly correlated with decreased cyclin D1 expression. In summary, these findings reveal an unexpected function of p16INK4a in homologous recombination- mediated DNA repair response and imply p16INK4a status as an independent marker to predict response of patients with HNSCC to radiotherapy.
Open Access
The tyrosine phosphatase PTPRO sensitizes colon cancer cells to anti-EGFR therapy through activation of SRC-mediated EGFR signaling
(Impact Journals, 2014-10-11) Asbagh, Layka Abbasi; Vázquez Urio, Iria; Vecchione, Loredana; Budinska, Eva; De Vriendt, Veerle; Baietti, Maria Francesca; Steklov, Mikhail; Jacobs, Bart ; Hoe, Nicholas ; Singh, Sharat; Imjeti, Naga-Sailaja; Zimmermann, Pascale; Sablina, Anna; Tejpar, Sabine; Ciencias; Zientziak
Inappropriate activation of epidermal growth factor receptor (EGFR) plays a causal role in many cancers including colon cancer. The activation of EGFR by phosphorylation is balanced by receptor kinase and protein tyrosine phosphatase activities. However, the mechanisms of negative EGFR regulation by tyrosine phosphatases remain largely unexplored. Our previous results indicate that protein tyrosine phosphatase receptor type O (PTPRO) is down-regulated in a subset of colorectal cancer (CRC) patients with a poor prognosis. Here we identified PTPRO as a phosphatase that negatively regulates SRC by directly dephosphorylating Y416 phosphorylation site. SRC activation triggered by PTPRO down-regulation induces phosphorylation of both EGFR at Y845 and the c-CBL ubiquitin ligase at Y731. Increased EGFR phosphorylation at Y845 promotes its receptor activity, whereas enhanced phosphorylation of c-CBL triggers its degradation promoting EGFR stability. Importantly, hyperactivation of SRC/EGFR signaling triggered by loss of PTPRO leads to high resistance of colon cancer to EGFR inhibitors. Our results not only highlight the PTPRO contribution in negative regulation of SRC/EGFR signaling but also suggest that tumors with low PTPRO expression may be therapeutically targetable by anti-SRC therapies.
Open Access
Measurement and analysis of mechanical noise in wind turbines
(Institute of Acoustics, 2016) Arana Burgui, Miguel; Machín Mindán, Jorge; San Martín Murugarren, Ricardo; Ciencias; Zientziak
Open Access
Nueva oferta educativa como respuesta al desarrollo del país: ingeniería agroindustrial
(Editorial Tecnológica de Costa Rica, 2016) Guzmán-Hernández, Tomás de Jesús; Fernández Rodríguez, Marcela; Villalobos Murillo, Johanna; Monreal Fernández, Ignacio; Rivero Marcos, Mikel; Ciencias; Zientziak
Costa Rica, donde la agricultura aún representa una parte importante del Producto Interno Bruto, se encuentra en un proceso de cambio de su economía nacional. La incorporación de valor agregado y la transformación de la materia prima procedentes de este sector se limitan al mejoramiento postcosecha en plantas empacadoras de la producción primaria y a la obtención de pulpas congeladas. Con este artículo se pretende dar a conocer la necesidad de contar con profesionales en agroindustria en tres regiones del país, las regiones Huetar Norte, Caribe y Chorotega y brindar una síntesis de lo alcanzado como propuesta de carrera. La agroindustria juega un papel importante en la economía local, pero muestra un débil desarrollo por falta de recurso humano crítico que condicione los cambios en dichas zonas y a nivel nacional. En ese sentido, se considera que la creación de la carrera de Ingeniería Agroindustrial en la Sede Regional San Carlos del Tecnológico de Costa Rica (TEC) es clave para impulsar al sector. Esta institución de educación superior ha contribuido desde su creación al desarrollo integral del país, desde una perspectiva universitaria estatal de calidad y competitividad nacional e internacional. Con este compromiso, el TEC ha elaborado una propuesta de oferta curricular acorde a las necesidades locales y del país, basada en estudios de mercado, en la experiencia internacional relacionada con el tema objeto de estudio, una extensa revisión bibliográfica y el análisis de la producción y las exportaciones de las regiones. La propuesta también responde a la iniciativa emprendedora y la estrecha vinculación del TEC con los sectores sociales y productivos.
Open Access
The effects of halogen substituents on the catalytic oxidation of benzylalcohols in the presence of dinuclear oxidovanadium(IV) complex
(Elsevier, 2017) Bikas, Rahman; Shahmoradi, Elaheh; Noshiranzadeh, Nader; Emami, Marzieh; Reinoso, Santiago; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
A new dinuclear complex of oxidovanadium(IV), namely [(VO)2(HL)(l-O)] (1), has been synthesized by the reaction of VO(acac)2 with the heptadentate N4O3-donor Schiff base ligand, 2-(5-Bromo-2-hydroxyphenyl)-1,3-bis(2-(5-bromo-2-hydroxybenzylideneamino)ethyl)imidazolidine (H3L). The complex has been characterized by elemental analysis, spectroscopic methods and single-crystal X-ray diffraction. The latter technique revealed that the vanadium ions have distorted octahedral geometry and are connected together by oxido and phenolic oxygen atoms. The bridging oxido ligand shares the equatorial positions of the two metal centers while the oxygen atom of the bridging phenol group connects the axial positions. The catalytic activity of this complex has been tested for the oxidation of some benzyl alcohol derivatives by using H2O2 as a green oxidant. In order to maximize the yields, the effects of various influential parameters in catalytic reactions such as the oxidant-to-substrate molar ratio, the temperature and the solvent, were studied. Moreover, the electronic and steric effects of halogen substituents on the phenyl group of the substrate were also explored by analyzing the oxidation of benzyl alcohol derivatives with F, Cl and Br atoms in the relative para-position (electronic effect), and of another set of substrates with a Cl substituent in relative ortho-, meta, and para-positions (steric effect). The results of these catalytic studies show that complex 1 catalyzes the oxidation of benzyl alcohol derivatives to the corresponding benzaldehydes with little amounts of the benzoic acid being detectable in the reaction mixture. Both the reaction conditions and the substituents on the phenyl group of the benzyl alcohols affect the selectivity and the activity of this catalytic system.
Open Access
Immobilization of polyoxometalates on tailored polymeric surfaces
(MDPI, 2018) Aguado-Ureta, Saioa; Rodríguez-Hernández, Juan; Campo, Adolfo del; Pérez-Álvarez, Leyre; Ruiz-Rubio, Leire; Vilas, José Luis; Artetxe, Beñat; Reinoso, Santiago; Gutiérrez Zorrilla, Juan M.; Ciencias; Zientziak
Herein we describe the preparation of hybrid polymer–inorganic interfaces by the immobilization of polyoxometalate nanoclusters on functionalized polymer surfaces. The polymeric surfaces were made of polystyrene-b-poly(acrylic acid)/polystyrene (PS-b-PAA/PS) blends by spin coating on a silicon wafer. The functionalization of the polymer film was obtained by interfacial migration of the amphiphilic block copolymer toward the interface upon water vapor annealing. The carboxylic acid functional groups contained in the PAA block were then employed to anchor the [LnIII(α-SiW11O39)]5− polyoxometalates (Ln: Ce, Er). This purpose was achieved by immersing the films in aqueous solutions of the in situ-formed inorganic nanoclusters. X-ray photoelectron and confocal Raman spectroscopies, together with atomic force microscopy, confirmed the immobilization of the inorganic species at the interface.
Open Access
Extruded catalysts with magnetic properties for biodiesel production
(Hindawi, 2018) Silveira Junior, Euripedes Garcia; Justo, Oselys Rodriguez; Perez, Victor Haber; Reyero Zaragoza, Inés; Serrano Lotina, Ana; Campos Ramírez, Leonardo; Santos Dias, Dayana F. dos; Ciencias; Zientziak
The aim of this work was to evaluate the performance of different extruded catalysts containing K2CO3 as active phase and adding conveniently γ-Al2O3 and/or sepiolite and magnetic particles on the biodiesel production from sunflower oil by the ethanolic route. Firstly, the content of the Fe3O4 on the catalyst (0.1, 0.2, 0.3, and 0.4 g Fe3O4/g of K2CO3/γ-Al2O3), after calcination step, was evaluated to verify the separation facility of the catalysts with magnetic properties from reactional medium, using an external magnetic field, at the end of biodiesel synthesis. After that, three different catalysts were considered for comparative purposes: (a) K2CO3/γ-Al2O3; (b) K2CO3/γ-Al2O3/Fe3O4; (c) K2CO3/γ-Al2O3/Sepiolite/Fe3O4 and subsequently characterized by dynamometry, TGA, SEM, VSM, BET, and XRD to determine their mechanical, structural, magnetic, and textural properties. However, their catalytic activities were determined through biodiesel production that was carried out in a glass volumetric reactor during 4 h, under magnetic stirring with 5% wt. of the catalyst and oil: ethanol molar ratio (1: 12) at 80°C reaction temperature. The best result, i.e., around 88% of biodiesel conversion, was obtained with catalyst K2CO3/γ-Al2O3/Sepiolite/Fe3O4 which showed also satisfactory textural and mechanical strength properties comparatively with the other catalytic derivatives. In addition, no agglomeration of the particles was observed during the reaction, and the magnetic property of this catalytic system was satisfactory for adequate separation from reactional medium seeking further reuse. The attained results are attractive for possible implementation at industrial scale and can be considered to mitigate drawbacks which resulting by using of homogeneous catalysts in the conventional processes.
Open Access
Flipped Classroom como herramienta para fomentar el trabajo colaborativo y la motivación en el aprendizaje de geología
(Edutec. Asociación para el desarrollo de la tecnología educativa, 2018) De Soto García, Isabel Sonsoles; Ciencias; Zientziak
Vivimos en una sociedad global y multicultural, lo que hace necesario que el profesorado se adapte a esta nueva realidad y asuma cambios profundos en sus prácticas educativas. En este contexto, las TIC pueden ayudar a los educadores a construir este tipo de sociedad y en concreto las flipped classroom presentan un futuro prometedor. Se ha desarrollado una actividad de flipped classroom en un módulo de Formación Profesional con el fin de facilitar el aprendizaje de la materia de geología. En este estudio se ha observado que esta metodología ha fomentado una actitud activa de los alumnos en el aula, un trabajo colaborativo y la motivación del alumnado lo que permite el desarrollo de competencias clave como trabajo en equipo y gestión de proyectos. Además de aumentar su rendimiento académico.
Open Access
Unraveling the role of transient starch in the response of Arabidopsis to elevated CO2 under long-day conditions
(Elsevier, 2018) Jáuregui Mosquera, Iván; Pozueta Romero, Javier; Aparicio Tejo, Pedro María; Baroja Fernández, Edurne; Aranjuelo Michelena, Iker; Zientziak; Ciencias; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
Previous studies on Arabidopsis under long-term exposure to elevated CO2 have been conducted using starch synthesis and breakdown mutants cultured under short day conditions. These studies showed that starch synthesis can ameliorate the photosynthetic reduction caused by soluble sugar-mediated feedback regulation. In this work we characterized the effect of long-term exposure to elevated CO2 (800 ppm) on growth, photosynthesis and content of primary photosynthates in long-day grown wild type plants as well as the near starch-less (aps1) and the starch-excess (gwd) mutants. Notably, elevated CO2 promoted growth of both wild type and aps1 plants but had no effect on gwd plants. Growth promotion by elevated CO2 was accompanied by an increased net photosynthesis in WT and aps1 plants. However, the plants with the highest starch content (wild type at elevated CO2, gwd at ambient CO2, and gwd at elevated CO2) were the ones that suffered decreased in in vivo maximum carboxylation rate of Rubisco, and therefore, photosynthetic down-regulation. Further, the photosynthetic rates of wild type at elevated CO2 and gwd at elevated CO2 were acclimated to elevated CO2. Notably, elevated CO2 promoted the accumulation of stress-responsive and senescence-associated amino acid markers in gwd plants. The results presented in this work provide evidence that under long-day conditions, temporary storage of overflow photosynthate as starch negatively affect Rubisco performance. These data are consistent with earlier hypothesis that photosynthetic acclimation can be caused by accelerated senescence and hindrance of CO2 diffusion to the stroma due to accumulation of large starch granules.
Open Access
Legume nitrogen utilization under drought stress
(Springer, 2018) Castañeda Presa, Verónica; Gil Quintana, Erena; Echeverría Obanos, Andrés; González García, Esther; Ciencias; Zientziak
Legumes account for around 27% of the world’s primary crop production and can be classified based on their use and traits into grain and forage legumes. Legumes can establish symbiosis with N-fixing soil bacteria. As a result, a new organ is formed, the nodule, where the reduction of atmospheric N2 into ammonia is carried out catalyzed by the bacterial exclusive enzyme nitrogenase. The process, highly energy demanding, is known as symbiotic nitrogen fixation and provides all the N needs of the plant, thus avoiding the use of N fertilizers in the context of sustainable agriculture. However, legume crops are often grown under non-fixing conditions since legume nodulation is suppressed by high levels of soil nitrogen occurring in chemically fertilized agro-environment. In addition, legumes are very sensitive to environmental stresses, being drought one of the significant constraints affecting crop production. Due to their agricultural and economic importance, scientists have carried out basic and applied research on legumes to better understand responses to abiotic stresses and to further comprehend plant–microbe interactions. An integrated view of nitrogen utilization under drought stress will be presented with particular focus on legume crops.
Open Access
Herramientas de gamificación para el aprendizaje de ciencias de la tierra
(Edutec. Asociación para el desarrollo de la tecnología educativa, 2018) De Soto García, Isabel Sonsoles; Ciencias; Zientziak
El porcentaje de abandono escolar en España es superior al de otros países de la Unión Europea, lo que hace necesario fomentar el rendimiento del alumnado y su motivación. En este contexto, la gamificación tiene un futuro prometedor ya que promueven la participación del alumnado y su deseo por aprender. Se han desarrollado tres actividades de gamificación (trivial, Kahoot y Socrative) para el estudio de ciencias de la tierra. Se ha observado que los alumnos prefieren las actividades de gamificación con soporte informático ya que crean un ambiente divertido que fomenta la participación y motivación. Sin embargo, también generan un aumento en la competitividad y los resultados obtenidos no son tan altos como los esperados inicialmente.
Open Access
Flora arvense de Navarra
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2018) Peralta de Andrés, Francisco Javier; Royuela Hernando, Mercedes; Ciencias; Zientziak
El origen de este libro se encuentra en el sitio web de Flora Arvense de Navarra, que fue desarrollado con el objetivo de facilitar el conocimiento de las malas hierbas de Navarra al alumnado de la Escuela Técnica Superior de Ingenieros Agrónomos de la Universidad Pública de Navarra, además de el de ser útil para personal investigador, técnico y agricultores de Navarra y territorios próximos. La edición de este libro se planteó para permitir la disponibilidad del contenido del sitio web en un soporte independiente de Internet.
Open Access
Gestión contextualizada del currículum en Educación Infantil
(Tecnos, 2018) Belletich Ruiz, Olga; Pérez de Villarreal Zufiaurre, Maider; Ciencias; Zientziak