Metodología 'SLIDE-4-U' para implicar al alumnado en el desarrollo de la clase presencial / How to involve students in the development of the face-to-face class: the 'SLIDE-4-U' methodology

Introducción: Desde hace unos años, tanto en grupos grandes como pequeños, y principalmente en clases en línea, se hapuesto en práctica la metodología ‘SLIDE-4-U’ o ‘una diapositiva para ti’ (2020PID-UB/023), con el objetivo de implicar alestudiante en su propio proceso de aprendizaje y en el de sus compañeros. Se consiguió mediante la participación delalumnado en la explicación en clase de diapositivas específicamente diseñadas para este fin. Métodos: La experiencia se llevó a cabo en el primer semestre del curso 2021-22 en la asignatura Nutrición Molecular delgrado de Nutrición Humana y Dietética (Universitat de Barcelona). Se preparó una sesión de seminario presencial centrada en inmunonutrición. El profesor dirigió la sesión seleccionando de forma aleatoria al estudiante, que debía explicar ladiapositiva sin preparación previa. Las explicaciones del alumnado fueron complementadas o corregidas por el profesordurante el desarrollo de la actividad. Al final del seminario se realizó una encuesta de opinión en la que se constató labuena aceptación de esta iniciativa (puntuaciones medias superiores a 4,2 sobre 5). Resultados: El alumnado consideró que era un reto explicar una diapositiva sin prepararla previamente y que este hecho,asociado a no saber quién haría la explicación, había provocado un cierto clima de nerviosismo. Ahora bien, la mayoríaestaba de acuerdo en que los esquemas/imágenes aportados fueron suficientes para poder desarrollar la actividad y quelas explicaciones hechas por los compañeros eran suficientemente correctas. Asimismo, también valoraban positivamente la participación del profesor a la hora de completar las explicaciones de sus compañeros. En general, la metodologíautilizada hizo que el alumnado fuera más consciente de que las diapositivas tienen una estructura y un objetivo, y de ladificultad de comunicar correctamente...(AU)

Introduction: Lately, both in large and small groups and mainly in online classes, the 'SLIDE-4-U' or 'one slide for you' methodology (2020PID-UB/023) has been put into practice, with the aim of involving the student in their own learning process and that of their classmates. It is achieved through the participation of the students in the explanation of slides in class, specially designed for this purpose. Methods: The experience was carried out in the first semester of the 2021-22 academic year in the subject Molecular Nutrition of the Human Nutrition and Dietetics degree (Universitat de Barcelona). A face-to-face seminar session focused on immunonutrition was prepared with this type of material. The teacher led the session by randomly selecting the student, who had to explain the slide without prior preparation. The explanations of the students were complemented and/or corrected by the teacher, during the development of the activity. At the end of the seminar, an opinion survey was carried out in which the good acceptance of this initiative was verified (average scores higher than 4.2 out of 5). Results: The students considered that it was a challenge to explain a slide without previously preparing it, and that this fact, associated with not knowing who would do the explanation, had caused a certain climate of nervousness. However, the majority agreed that the diagrams/images provided were sufficient to be able to carry out the activity and that the explanations made by the classmates were correct enough. Likewise, they also positively valued the teacher's participation when completing the explanations of their classmates. In general, the methodology used made the students more aware that the slides have a structure and an objective, and of the difficulty of communicating correctly...(AU)

Lactobacillus fermentum CECT5716 supplementation in rats during pregnancy and lactation affects mammary milk composition.

Lactobacillus fermentum CECT5716 has shown immunomodulatory action and reduction of infections; therefore, it is suggested to be appropriate for use in early life. The present study aimed to assess the effects of the supplementation of L. fermentum CECT5716 in rats during gestation and lactation periods on the composition of some mammary milk components such as microbiota, fatty acid (FA) profile, and immunoglobulins. Wistar rats were supplemented by oral gavage with 1010 cfu/d of Lactobacillus fermentum CECT5716 (n = 6) or vehicle (n = 6) for 5 wk, comprising the 3 wk of gestation and the first 2 wk of lactation. At the end of the intervention, milk, mammary glands, and cecal contents were obtained for the tracking of the probiotic strain by nested PCR-quantitative PCR. Additionally, milk samples were used for the analysis of microbiota by 16S rRNA sequencing, FA by gas chromatography-flame ionization detector, and immunoglobulin by Luminex (Luminex Corporation, Austin, TX). Although L. fermentum CECT5716 administration did not modify the overall composition of milk microbiota, the strain was detected in 50% of the milk samples of rats supplemented with the probiotic. Moreover, probiotic administration induced beneficial changes in the FA composition of milk by increasing total PUFA, including linoleic and α-linolenic acids, and decreasing the proportion of palmitic acid. Finally, the milk of the rats treated with the probiotic showed a 2-fold increase of IgA levels. The supplementation with L. fermentum CECT5716 during pregnancy and lactation periods improved the milk composition of FA and immunoglobulins. These effects were not linked to the presence of the strain in milk, thus suggesting that the mechanism is connected to intestinal compartment. These findings provide novel insight into a potential new approach for infants to benefit from better nutrition, development of a healthy immune system and microbiota, and protection from gastrointestinal infections.

Immunomodulatory and Prebiotic Effects of 2'-Fucosyllactose in Suckling Rats.

Human milk oligosaccharides are unconjugated complex glycans present in high concentration in human milk that serve as pre-biotics and immunomodulators. They are not primarily absorbed or metabolized by the infant and reach the lower part of the intestinal tract unaltered. One of the main oligosaccharides found in human milk is 2'-fucosyllactose (2'-FL). This study aimed to investigate the effects of daily oral administration of 2'-FL in healthy suckling rats. From days 2 to 16 of life, rats were daily given the oligosaccharide (2'-FL) or vehicle (REF), weighed and their stool characteristics were assessed. On days 8 and 16 of life the morphometry, intestinal architecture, and cytokine release, mesenteric lymph nodes cell composition, plasma immunoglobulin concentrations, fecal microbiota composition, cecal short-chain fatty acids content, and the urinary metabolic profile were assessed. Animals given 2'-FL showed higher plasma IgG and IgA and more T cell subsets in the mesenteric lymph nodes on day 16. Moreover, at intestinal level, villus heights, and areas were increased on day 8. Cecal samples displayed a higher Lactobacillus proportion and a different urinary metabolic profile was observed on day 8, and a higher proportion of butyrate on day 16. In conclusion, supplementation of 2'-FL in early life has a pre-biotic and intestinal trophic effect and promotes maturation of the immune system.

PGE2 promotes Ca2+-mediated epithelial barrier disruption through EP1 and EP4 receptors in Caco-2 cell monolayers.

We recently demonstrated that PGE(2) induces the disruption of the intestinal epithelial barrier function. In the present study, our objectives were to study the role of PGE(2) receptors (EP(1)-EP(4)) and the signaling pathways involved in this event. Paracellular permeability (PP) was assessed in differentiated Caco-2 cell cultures from d-mannitol fluxes and transepithelial electrical resistance (TER) in the presence of different PGE(2) receptor agonists (carbacyclin, sulprostone, butaprost, ONO-AE1-259, ONO-AE-248, GR63799, and ONO-AE1-329) and antagonists (ONO-8711, SC-19220, AH-6809, ONO-AE3-240, ONO-AE3-208, and AH-23848). The results indicate that EP(1) and EP(4) but not EP(2) and EP(3) might be involved in PP regulation. These effects were mediated through PLC-inositol trisphosphate (IP(3))-Ca(2+) and cAMP-PKA signaling pathways, respectively. We also observed an increase in intracellular Ca(2+) concentration ([Ca(2+)](i)) strengthened by cAMP formation indicating a cross talk interaction of these two pathways. Moreover, the participation of a conventional PKC isoform was shown. The results also indicate that the increase in PP may be correlated with the redistribution of occludin, zona occludens 1 (ZO-1), and the perijunctional actin ring together with an increase in myosin light chain kinase activity. Although the disruption of epithelial barrier function observed in inflammatory bowel disease (IBD) patients has been traditionally attributed to cytokines, the present study focused on the role of PGE(2) in PP regulation, as mucosal levels of this eicosanoid are also increased in these inflammatory processes.

Effect of pH on L- and D-methionine uptake across the apical membrane of Caco-2 cells.

The transport systems involved in intestinal methionine (Met) absorption are described as Na(+)-dependent and Na(+)-independent mechanisms. However, since recent studies have suggested the importance of the H(+) gradient as a driving force for intestinal nutrient absorption, the aim of the present work was to test whether Met transport across the apical membrane of Caco-2 cells is affected by extracellular pH. The results show that l- and d-Met uptake was increased by lowering extracellular pH from 7.4 to 5.5, in both the presence and absence of Na(+). Cis-inhibition experiments revealed that inhibition of l-Met transport by 2-aminobicyclo[2,2,1]heptane-2-carboxylic acid (BCH) or l-lysine (l-Lys) was higher at a pH of 5.5. Moreover, the BCH-insensitive component was not affected by pH, whereas the l-Lys-insensitive component was increased by lowering extracellular pH, thus suggesting the participation of system L. The contribution of another mechanism, sensitive to both BCH and l-Lys, was also considered. The inhibition obtained with taurine (Tau) was also higher at a pH of 5.5, thus suggesting the involvement of system B(0,+) on pH-stimulated component. As for d-Met uptake, the results showed higher inhibition with l-Lys and Tau at a pH of 5.5 and no effect on the l-Lys- or Tau-insensitive component. In conclusion, Met transport across the apical membrane of Caco-2 cells is increased by low extracellular pH as the result of the stimulation of two transport systems functionally identified with systems L and B(0,+) for l-Met and with system B(0,+) for d-Met.

Monocarboxylate transporter 1 mediates DL-2-Hydroxy-(4-methylthio)butanoic acid transport across the apical membrane of Caco-2 cell monolayers.

The methionine hydroxy analogue DL-2-hydroxy-(4-methylthio)butanoic acid (DL-HMB) is a supplementary source of methionine commonly added to commercial animal diets to satisfy the total sulfur amino acid requirement. In this study, we characterized DL-HMB transport across the apical membrane of Caco-2 cells to identify the transport mechanism involved in the intestinal absorption of this methionine source. DL-HMB transport induced a significant decrease in intracellular pH (pH(i)) and was inhibited in the presence of the protonophore carbonyl cyanide 4-(trifluoromethoxy)-phenylhydrazone. Moreover, both Na(+) removal and 5-(N-ethyl-N-isopropyl)amiloride, an inhibitor of apical Na(+)/H(+) exchanger (NHE3), significantly reduced substrate uptake and pH(i) recovery, suggesting cooperation between H(+)-dependent DL-HMB transport and NHE3 activity. cis-Inhibition experiments with L-Ala, beta-Ala, D-Pro, betaine, or glycyl-sarcosine excluded the participation of systems proton amino acid transporter 1 and peptide transporter 1. In contrast, alpha-cyano-4-hydroxycinnamate, phloretin, L-lactate, beta-hydroxybutyrate, butyrate, and pyruvate, inhibitors and substrates of monocarboxylate transporter 1 (MCT1), significantly reduced DL-HMB uptake. Dixon plot analysis of L-lactate transport in the presence of DL-HMB revealed a competitive interaction (inhibition constant, 17.5 +/- 0.11 mmol/L), confirming the participation of system MCT1. The kinetics of DL-HMB uptake was described by a model involving passive diffusion and a single low-affinity, high-capacity transport mechanism (K(D), 1.9 nL/microg protein; K(m), 13.1 +/- 0.04 mmol/L; and V(max), 43.6 +/- 0.14 pmol/microg protein) compatible with MCT1 kinetic characteristics. In conclusion, the methionine hydroxy analogue is transported in Caco-2 cell apical membrane by a transport mechanism with functional characteristics similar to those of MCT1.