Effect of elevated inorganic carbon on the cytosolic homeostasis of NO3- in the marine angiosperm Posidonia oceanica (L.) Delile

The marine angiosperm Posidonia oceanica is a mediterranean endemism of great ecological significance. As other marine plants, P. oceanica has adapted secondarily to the marine environment and develop anew different mechanisms to colonize it. Among others, this plant has developed a plasma membrane system for the direct uptake of bicarbonate. In this work we have developed both NO3- and Cl- selective microelectrodes for the continuous monitoring of the intracellular (cytosolic) NO3- and Cl-. In the light, leaf mesophyll cells show a cytosolic NO3- concentration of 5.7±0.2 mM (n=10), while in the dark cytosolic NO3- raises up to 8.7±1.1 mM; these values are in the range of concentrations quoted for Arabidopsis thaliana (Cookson et al., 2005). The enrichment of natural seawater (NSW) with 3 mM NaHCO3 caused a decrease of the cytosolic NO3- concentration of 1 mM and a decrease of the cytosolic concentration of Cl- of 3.5 mM. The saturation of NSW with 1000 µL CO2 L-1 produced a lower diminution of the cytosolic NO3- (0.3 mM). In the presence of 0.1 mM of the plasma membrane permeable inhibitor of the carbonic anhydrase (EZ) the diminution of cytosolic NO3- caused by the same concentration of CO2 was much lower, 0.1 mM. The addition of inorganic carbon, either HCO3- or CO2, has an effect on the cytosolic mechanisms for anionic homeostasis, one of which is the opening of the slow anion channels. These channels are permeable to NO3- and Cl- and could elicit the efflux of these ions. In P. oceanica, the response in the presence of EZ points out that the inorganic carbon species that cause the NO3-/Cl- efflux is HCO3-. This effect could contribute to plant biomass N dilution observed in elevated CO2. References: Cookson et al. 2005. Plant Physiology 138, 1097–1105.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

HCO3- enrichment causes cytosolic NO3- efflux in Posidonia oceanica leaf cells

Posidonia oceanica is a seagrass, the only group of vascular plants to colonize the marine environment. Seawater is an extreme yet stable environment, characterized by high salinity, alkaline pH and low availability of essential nutrients, such as nitrate or phosphate. In addition, in aquatic environments the supply of CO2 for the photosynthesis is limited by diffusion and therefore many aquatic plants use HCO3- as the inorganic carbon source for photosynthesis. Previous results have shown that Na+ -dependent transport systems operate on the plasma membrane of P. oceanica mesophyll leaf cells for the high-affinity NO3-, Pi or amino acids uptake. Also, a direct transport of HCO3- driven by H+ has been found in this species that provides inorganic carbon for photosynthesis and could be a significant component of a carbon concentrating mechanism in this species. Interestingly, this HCO3- direct uptake caused the efflux of chloride from the cytosol, probably through S-type anion channels, pointing that other anions could also be removed from the cytosol. This hypothesis could be relevant in the case of NO3-, since the decrease of cytosolic NO3- in response to HCO3- enrichment could limit N-assimilation. Here we analyse the effect of HCO3- increase on NO3- uptake and cytosolic homeostasis in P. oceanica. Enrichment of natural seawater with 3 mM HCO3- evokes the on-going decrease of cytosolic NO3-, from 5.7 ± 0.2 to 4.8 ± 0.7 mM after 40 min of treatment. The incubation of P. oceanica leaf pieces in 3 mM HCO3- NSW causes an initial increase of NO3- concentration in the medium. Maximum efflux (21 nmol NO3- gFM-1 min-1) occurs within the first minute of incubation. Then, external NO3- is depleted from the medium at lower net uptake rate than the value observed in non HCO3- -enriched natural seawater. These results fit the hypothesis that HCO3- enrichment causes the nitrogen loose and could impair nitrogen assimilation promoting N biomass impoverishment.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Spanish MINECO, projects BFU2017-85117-R and BIO2016-81957-RED

Na+-dependent NO3- uptake in leaf cells of the seagrass Posidonia oceanica (L.) Delile

Posidonia oceanica (L.) Delile is an endemic Mediterranean seagrass of recognized ecological significance and, as other seagrasses, this species has secondarily adapted to live in the marine environment. In this alkaline medium with a high Na+ concentration (0.5 M), the high inwardly directed electrochemical potential gradient for sodium is used in the seagrass Zostera marina to energize the uptake of nitrate1 and phosphate that usually occur at concentration below 10 µM. Here we summarize several evidences for the operation of a sodium-dependent high-affinity nitrate transport system at the plasma membrane of the mesophyll leaf cells of P. oceanica. Leaf cells of P. oceanica possess a H+-ATPase as a primary pump, exhibit a plasma membrane potential (Em) of -174 ± 10 mV and show reduced Na+ permeability. The addition of micromolar nitrate concentrations induces membrane depolarizations that show saturation kinetics. Curve fitting of the values renders a semisaturation constant (Km) of 21.3 ± 6.6 μM and a maximum depolarization (Dmax) of 7 ± 1 mV. In dark conditions, Dmax decreases by fifty percent but no significant effect is observed on the Km value. On the other hand, nitrate induced depolarizations show sodium dependence. The depolarizations induced by 100 µM NO3- in media containing increasing Na+ concentrations (from 0 to 250 mM) show saturation kinetics, rendering a Km value of 16 ± 5 mM Na+. Moreover, the depolarization induced by 100 µM NO3- is accompanied by a simultaneous increase of cytosolic sodium, measured by Na+-sensitive microelectrodes, of 0.4 ± 0.2 mM above the resting cytosolic sodium concentration (17 ± 2 mM). Finally, nitrate uptake rates, measured in depletion experiments, decreases by 50% and 80% in dark conditions and in the absence of Na+, respectively, compared with control conditions (0.5 M Na+ and light). All together, these results strongly suggest that NO3- uptake in P. oceanica leaf cells is mediated by a high-affinity nitrate carrier that uses Na+ as the driving ion. 1 Rubio et al. (2005). J. Exp. Bot, 412: 613-622. Project Funding: CTM 2011-30356. (MEC)Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Enseñanza basada en contenidos: una experiencia para el desarrollo de competencias del EEES en grados en Ingeniería Informática

En esta ponencia describimos una estrategia docente diseñada para potenciar la implicación del alumno en el desarrollo de las clases. Aprovechando la creación de grupos con docencia en inglés en los grados en Ingeniería Informática, hemos utilizado en nuestra asignatura una metodología activa basada en la participación del alumno durante las clases. En estos grupos, un objetivo adicional es que el alumno progrese en su dominio del inglés, que claramente se alcanzará si el alumno practica activamente el idioma. Siguiendo esta idea, hemos enfocado nuestra asignatura de forma que el alumno sea el protagonista de las clases, como se indica en el Espacio Europeo de Educación Superior (EEES), realizando diversas actividades durante el curso. Con este enfoque hemos obtenido buenos resultados finales, a nivel de calificaciones y de dominio del idioma, además de desarrollar otras competencias del EEES (capacidad de exposición en público, trabajo en grupo, actitud crítica, etc).SUMMARY -- This paper describes a teaching approach designed to promote the involvement of students in class. Due to the creation of English-teaching groups in Computer Engineering Degrees, we have used an active methodology based on the participation of students in class. In these groups, an additional goal is the progress of students in their fluency in English, an aspect that will be clearly achieved if they actively practice this language. Following this idea, we have oriented our subject so that the student plays an active role in class, as indicated in the European Higher Education Area (EHEA), by means of different activities during the semester. With this approach, we have obtained good final results in terms of qualifications and English level, and other skills indicated by the EHEA (such as public presentation skills, cooperative work, critical attitude,...).Peer Reviewe

Multicystic urothelial carcinoma of the bladder with gland-like lumina and with signet-ring cells. A case report

We present the case of 80-year-old male with superficial papillary urothelial carcinoma of the urinary bladder with striking multicystic architecture with a combination of features of urothelial carcinoma with gland-like lumina, with signet-ring cell differentiation and microcystic pattern. However, the tumor shared the morphologic features of several variants of urothelial carcinoma, the most important differential diagnosis covered so-called florid Brunneriosis, cystitis cystica, and primary adenocarcinomas of the urinary bladder

The difference between the metric dimension and the determining number of a graph

We study the maximum value of the difference between the metric dimension and the determining number of a graph as a function of its order. We develop a technique that uses functions related to locating-dominating sets to obtain lower and upper bounds on that maximum, and exact computations when restricting to some specific families of graphs. Our approach requires very diverse tools and connections with well-known objects in graph theory; among them: a classical result in graph domination by Ore, a Ramsey-type result by Erdős and Szekeres, a polynomial time algorithm to compute distinguishing sets and determining sets of twin-free graphs, k-dominating sets, and matchings

On the metric dimension, the upper dimension and the resolving number of graphs

This paper deals with three resolving parameters: the metric dimension, the upper dimension and the resolving number. We first answer a question raised by Chartrand and Zhang asking for a characterization of the graphs with equal metric dimension and resolving number. We also solve in the affirmative a conjecture posed by Chartrand, Poisson and Zhang about the realization of the metric dimension and the upper dimension. Finally, we prove that no integer a≥4a≥4 is realizable as the resolving number of an infinite family of graphs

Tutte uniqueness of locally grid graphs

A graph is said to be locally grid if the structure around each of its vertices is a 3 × 3 grid. As a follow up of the research initiated in [4] and [3] we prove that most locally grid graphs are uniquely determined by their Tutte polynomial.Ministerio de Ciencia y Tecnología BFM2001-2474-ORIJunta de Andalucía PAI FQM-16

Incidencia de las técnicas y los métodos de estudio en el rendimiento académico de los estudiantes de ciencias sociales de la Farem-Chontales

La presente investigación tiene como objetivo determinar la incidencia de las técnicas y los métodos de estudio en el rendimiento académico de los estudiantes de la carrera de Ciencias Sociales de la FAREM-Chontales. Los resultados de este estudio son muy importantes ya que ofrece información que orienta a asumir acciones de mejora y toma de decisiones educativas. En educación existen una gran variedad de explicaciones sobre las principales causas que provocan el bajo rendimiento académico en los estudiantes, pero una de las más frecuentes es la falta de implementación de técnicas y métodos de estudio. Las técnicas y los métodos de estudio son los distintos procedimientos para mejorar el aprendizaje. Por ello el presente trabajo describe la relación existente entre ambos y su incidencia con el rendimiento académico de los estudiantes. También se resalta la importancia de la implementación de las mismas, debido a que son de gran utilidad, para que se obtengan resultados favorables, en el desarrollo de la vida estudiantil. En ese sentido, para una mejor comprensión este informe final de investigación, se encuentra estructurado en apartados; el primero relacionado con el planteamiento del problema, donde se describe como causa fundamental del bajo rendimiento académico en los estudiantes de la carrera de Ciencias Sociales la falta de implementación de las técnicas y los métodos de estudio. Un segundo apartado de esta investigación es la justificación donde se retoma textualmente que el propósito de este trabajo es analizar la problemática de las técnicas y los métodos de estudio y la incidencia en el rendimiento académico. En el apartado de los antecedentes se encontrará estudios nacionales e internacionales referidos a la incidencia de las técnicas y los métodos de estudi

El arte dramático para la mejora de las habilidades sociales en estudiantes de tercero de secundaria UGEL Nº 06, Ate - Vitarte, Lima, 2017

El presente trabajo de investigación titulado “El arte dramático para la mejora de las habilidades sociales en estudiantes de tercero de secundaria UGEL nº 06, Ate - Vitarte, Lima, 2017”, cuyo propósito fue determinar la influencia de la dramatización en el desarrollo de las habilidades sociales en estudiantes de tercero de secundaria. La metodología empleada fue el enfoque cuantitativo, la investigación fue aplicada, el diseño de la investigación cuasi experimental, que recogió la información en un periodo específico, del Pre y Postest del programa de dramatización para mejorar las habilidades sociales en los estudiantes de la muestra tercero de secundaria, la muestra estuvo conformada por 60 estudiantes divididos en dos grupos, control y experimental, conformados por 30 estudiantes cada uno. La técnica empleada fue de observación y el instrumento una lista de cotejo. Los resultados fueron analizados mediante el estadígrafo no paramétrico, en este caso, mediante “U” de Mann-Withney. Se concluyó que existe diferencia significativa en las habilidades sociales entre el grupo control y el grupo experimental (U de Mann-Whitney = 26,500, sig = 0,000)