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

Los foros virtuales : Propuestas prácticas para su utilización educativa

Los foros virtuales cada vez más se están configurando como una poderosa herramienta de comunicación y trabajo colaborativo. Estos espacios de trabajo y diálogo proporcionan la posibilidad de participación de una forma reflexiva, frente a otras herramientas de comunicación y trabajo de carácter sincrónico, donde la inmediatez supone un obstáculo a la reflexión y el análisis detenido de las aportaciones de los demás participantes. En base a esta importancia, el papel de coordinador, moderador, desempeñado en muchos casos por el docente, cobra un papel de gran relevancia, pues será quién reconduzca, haga reflexionar, proponga nuevas orientaciones, etc., dentro del espacio del foro. Estos dos elementos, la capacidad de reflexión y el papel del moderador, son fundamentales para una óptima utilización de los foros. Así mismo, se tratará de ofrecer algunas sugerencias o propuestas didácticas para poner en práctica, orientadas sobre todo a la aplicación en las ciencias sociales, pero con posibilidades de adaptación a otros ámbitos educativosEje: TIC, flexibilización, trabajo colaborativoRed de Universidades con Carreras en Informática (RedUNCI

The problem of living in the sea: the uptake of inorganic carbon and nutrients in Posidonia oceanica (L.) Delile

The genus Posidonia exhibits a peculiar geographical distribution. It is composed by nine species, eight of which are distributed along the Australian coasts and only one, Posidonia oceanica (L.) Delile, is a Mediterranean endemism. Like other angiosperms, P. oceanica has adapted secondarily to the marine environment, and has developed anew mechanisms to face a liquid and alkaline medium (pH 8.2) that contains a high salt concentration (0.5 M NaCl). The liquid environment limits the diffusive flow of CO2 and nutrients and, furthermore, CO2 dissolves in water and forms HCO3-, the more abundant chemical species of inorganic carbon at pH 8.2. Like other green plants P. oceanica uses CO2 for photosynthesis. In addition, this species shows a transport system in the plasma membrane for the direct uptake of HCO3-, that uses H+ as the driving ion. The addition of HCO3- provokes a transient hyperpolarization of the plasma membrane followed by a depolarization; at the same time, the cytosolic pH (pHc) becomes transiently acidic and next it gets alkaline, and remains alkaline throughout the HCO3- pulse. The alkalinization of the pHc is due to the cytosolic accumulation of HCO3- and OH- and it is sensitive to the addition of ethoxyzolamide, an inhibitor of the internal carbonic anhydrase. The increase of negative charges in the cytosol triggers the release of Cl- to recover the values of the resting membrane potential. The plasmalemma of P. oceanica exhibits a reduced Na+ permeability and shows a H+/Na+ antiporter activity that keeps low and relatively constant the cytosolic Na+ concentration (17 mM Na+). The inside negative membrane potential (-178 mV) and the low [Na+]c generate a tremendous Na+-motive force that this plant uses for the high affinity transport of NO3- (Km= 21 µM), and of the amino acids alanine (Km= 37 µM) and cysteine (Km= 10 µM). The uptake of these compounds shows a strict dependence on the presence of Na+ in the medium. Moreover, the addition of micromolar concentrations of NO3-, alanine or cysteine gives rise to millimolar increments of [Na+]c. Experiments with external LIX pH mini-electrodes show that the uptake of glucose is not Na+ but H+ dependent. Thus, the model for the ion transport energization in this species seems to be mixed, with a H+-ATPase as the primary pump and a series of carriers that use H+ (HCO3-, Na+, glucose) or Na+ (NO3-, amino acids) as the driving ion. Project Funding: CTM 2011-30356 (MEC)Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Working Methodology with Public Universities in Peru during the Pandemic—Continuity of Virtual/Online Teaching and Learning

This article describes the consultancy provided by the UTEC-UNED-TECSUP University Consortium to six national universities in Peru, during the COVID-19 state of emergency. This action aims to promote the techno-pedagogical change from a face-to-face to a virtual/online educational context. The process consists of three stages that ensured the continuity of the virtual/online educational service: diagnosis, design, and training, to strengthen instructional and digital competencies, support, and techno-pedagogical monitoring. It includes the basic principles of constructivist and constructionist learning theories for active and quality teaching and learning for the agents involved, and, in addition, the guidelines set by the emerging Peruvian regulations during the pandemic to move towards a digital university model according to the times. After a 157-day intervention, the analysis of the results raises some reflections: the importance of the socio-cultural context and its influence on the concept and development of the instructional act; the concept of distance learning in territories where connectivity is the main difficulty, and the university institution, in terms of a non-presential educational model with open and versatile methodologies, which anticipates a long process, involves a scheduled follow-up, requires fluid communication and demands continuous feedback: It is hereby stated for the record that the UTEC-UNED-TECSUP CONSORTIUM, made up of the companies: TECSUP N◦1, TECSUP ASSOCIATION N◦ 2 called “TECSUP”, UNIVERSITY OF ENGINEERING AND TECHNOLOGY called “UTEC”, and NATIONAL UNIVERSITY OF DISTANCE EDUCATION called “UNED”, provided the service of: “DEVELOP THE SUPPORT PROGRAMME TO DESIGN AND IMPLEMENT STRATEGIES FOR THE CONTINUITY OF THE HIGHER EDUCATION SERVICE OF PUBLIC UNIVERSITIES” to the Executing Unit 118 “Improvement of the Quality of Basic and Higher Education”—Programme for the Improvement of the Quality and Relevance of University and Technological Higher Education Services at National Level of the Ministry of Education. Contract number: 063-2020-MCEBS/Total cost of the service: S/.1,822,165.5

Training Plan for the Continuity of Non-Presential Education in Six Peruvian Universities during COVID-19

This article shows the response offered by the UTEC-UNED-TECSUP Consortium to six Peruvian public (national) universities aimed at strengthening the digital competences of their communities, made up of managers, teachers, students, and support technicians. The contextual and situational diagnosis, which covered organizational, technological, and competence dimensions, revealed a series of cross-cutting needs related to technological skills that prevented the training or mobilization of the digital competences necessary for progress in the other dimensions under study. The response was an online training plan, consisting of three training programs and eighty-three courses. The pedagogical strategy was based on the scaling of competence achievements that ended with problem-solving and applications in daily activities. The accompaniment was carried out through virtual tutorials, distributed via synchronous and asynchronous sessions. In total, 5034 were involved—347 were teachers and managers, 4932 were students, and 25 were technical staff. The pedagogical and socio-emotional limitations of the university community, as well as the scarcity of technological resources and poor connectivity, meant that the plan was only partially implemented. Moreover, the short and intense period of development to which the universities were subjected was also a factorIt is hereby stated for the record that the UTEC-UNED-TECSUP Consortium—made up of the TECSUP N◦1 and TECSUP Association N◦ 2 (TECSUP); the University of Engineering and Technology (UTEC); and the National University of Distance Education (UNED)—provided funding through the Executing Unit 118 “Improvement of the Quality of Basic and Higher Education”— Program for the Improvement of the Quality and Relevance of University and Technological Higher Education Services at National Level of the Ministry of Education. Contract number: 063-2020- MCEBS; total cost of the service: S/1,822,165.

Limits and possibilities in the techno-pedagogical virtualization process of Peruvian universities

El Consorcio universitario UTEC-UNED-TECSUP participó en la octava convocatoria del Programa de apoyo al diseño e implementación de estrategias para la continuidad del servicio educativo superior de las universidades públicas del Ministerio de educación peruano (PMESUT), cuyo objetivo era fomentar la continuidad del servicio educativo no presencial de las universidades públicas. Este artículo presenta el asesoramiento a cuatro universidades con el objetivo de garantizar la digitalización de la enseñanza tras la pandemia. Realizado el diagnóstico, se llevó a cabo la virtualización tecno-pedagógica de 138 cursos modelo en tres fases: planificación; diseño curricular y acompañamiento docente; e implementación de los cursos en el aula virtual. Las limitaciones se relacionaron con las brechas digitales existentes: escasez de tiempo, autorregulación personal y escasa formación en competencias pedagógicas y digitales de los docentes. Se buscaron medidas de apoyo y tutorización individualizadas, aumentando el número de sesiones sincrónicas que facilitaran la evaluación. El feedback persiguió la información, interacción y responsabilidad sobre lo realizado y la mejora del acto didáctico en modalidad virtual. Como conclusión se destaca la complejidad del proceso y el alto nivel de exigencia para la obtención de resultados que, siendo positivos atravesaron varios obstáculos provenientes de los diferentes agentes y elementos implicados.UTEC-UNED-TECSUP University Consortium have participated in the eighth call for proposals of the Program to Support the Design and Implementation of Strategies for the Continuity of Higher Education Services in Public Universities of the Ministry of Education of Peru (PMESUT), whose objective was to promote the continuity of non-classroom educational services in public universities. This article presents the assessment carried out in four universities, with the aim of ensuring the digitization of teaching after the onset of the pandemic. After the diagnosis and their corresponding training process, the techno-pedagogical virtualization of 138 model courses was carried out, consisting of three phases: planning, curricular design and teaching support and implementation of the courses in the virtual classroom. The limitations were related to the existing digital gaps: shortage of time, personal self-regulation, and scarce training in pedagogical and digital competencies of teachers. Individualized support and tutoring measures were sought, increasing the number of synchronous sessions to facilitate evaluation. Feedback sought information, interaction, and responsibility for what was done and the improvement of the didactic act in virtual mode. In conclusion, the complexity of the process and the high level of demand for obtaining results that, although positive, went through several obstacles coming from the different agents and elements involved

Effect of in vitro gastrointestinal digestion on the antibacterial activity of bioactive dairy formulas supplemented with lactoferrin against Cronobacter sakazakii

Milk is a source of proteins with high nutritional value and relevant biological activities. Bioactive milk proteins, like lactoferrin, are important for newborn development and can also be used as ingredients in functional products to improve health. Lactoferrin is essential in infant’s diet, since protects against infections and promotes immune system maturation. Bovine lactoferrin is used to supplement formula milk in order to strengthen baby’s defences against some pathogenic bacteria. Thus, lactoferrin supplemented formula can be a barrier against emergent pathogens, such as Cronobacter sakazakii, which has caused great concern in the last few years. Milk proteins generate bioactive peptides in the digestion process, and it is known that industrial processing can modify their susceptibility to digestion. Treatments such as heating have been shown to denature whey proteins and make them more easily digestible. Therefore, the aim of this study was to analyze the effect of technological treatments and gastrointestinal digestion on the antibacterial activity against C. sakazakii of proteins present in dairy formulas supplemented with lactoferrin. Commercial bovine lactoferrin has been shown to have antibacterial activity against C. sakazakii, both in the native state and after static in vitro gastrointestinal digestion. In addition, the digests obtained from dairy formulas subjected to technological treatments, either homogenization or pasteurization, have higher antibacterial activity than non-treated formulas. The release of low molecular weight peptides during the in vitro gastric digestion is probably the cause that would explain the enhanced antibacterial activity of the digested dairy formulas