Modulating vesicle adhesion by electric fields

We introduce an experimental setup for modulating adhesion of giant unilamellar vesicles to a planar substrate. Adhesion is induced by the application of an external potential to a transparent indium tin oxide-coated electrode (the substrate), which enables single-vesicle studies. We demonstrate tunable and reversible adhesion of negatively charged vesicles. The adhesion energy at different potentials is calculated from the vesicle shape assessed with confocal microscopy. Two approaches for these estimates are employed: one based on the whole contour of the vesicle and a second based on the contact curvature of the membrane in the vicinity of the substrate. Both approaches agree well with each other and show that the adhering vesicles are in the weak adhesion regime for the range of explored external potentials. Using fluorescence quenching assays, we detect that, in the adhering membrane segment, only the outer bilayer leaflet of the vesicle is depleted of negatively charged fluorescent lipids, while the inner leaflet remains unaffected. We show that depletion of negatively charged lipids is consistent Poisson-Boltzmann theory, taking into account charge regulation from lipid mobility. Finally, we also show that lipid diffusion is not significantly affected in the adhering membrane segment. We believe that the approaches introduced here for modulating and assessing vesicle adhesion have many potential applications in the field of single-vesicle studies and research on membrane adhesion

Dietary Mg Supplementation Decreases Oxidative Stress, Inflammation, and Vascular Dysfunction in an Experimental Model of Metabolic Syndrome with Renal Failure

Background: Metabolic syndrome (MetS) and chronic kidney disease (CKD) are commonly associated with cardiovascular disease (CVD) and in these patients Mg concentration is usually decreased. This study evaluated whether a dietary Mg supplementation might attenuate vascular dysfunction through the modulation of oxidative stress and inflammation in concurrent MetS and CKD. Methods: A rat model of MetS (Zucker strain) with CKD (5/6 nephrectomy, Nx) was used. Nephrectomized animals were fed a normal 0.1%Mg (MetS+Nx+Mg 0.1%) or a supplemented 0.6%Mg (MetS+Nx+Mg0.6%) diet; Sham-operated rats with MetS receiving 0.1%Mg were used as controls. Results: As compared to controls, the MetS+Nx-Mg0.1% group showed a significant increase in oxidative stress and inflammation biomarkers (lipid peroxidation and aortic interleukin-1b and -6 expression) and Endothelin-1 levels, a decrease in nitric oxide and a worsening in uremia and MetS associated pathology as hypertension, and abnormal glucose and lipid profile. Moreover, proteomic evaluation revealed changes mainly related to lipid metabolism and CVD markers. By contrast, in the MetS+Nx+Mg0.6% group, these parameters remained largely similar to controls. Conclusion: In concurrent MetS and CKD, dietary Mg supplementation reduced inflammation and oxidative stress and improved vascular function.This research was funded by a Spanish government grant from the Programa Nacional I+D+I 2008–2011 from the MINECO-Instituto de Salud Carlos III (PI20/0660 and PI21/00654) with co-financing from European Funds (FEDER) and EUTOX and REDinREN from the ISCIII, Consejería de Salud (grants PI-0071-2021) from the Junta de Andalucía and Grant PY20_00773 from Consejería de Innovación, Ciencia y Empleo from the Junta de Andalucía. J.M.D.-T. hold a Sara Borrell contract by the Spanish Ministry of Science, Innovation and Universities, Carlos III Health Institute (ISCIII), co-funded by European Social Fund (European Social Fund-Investment in your future). Y.A. and J.R.M.-C. are senior researchers supported by the Nicolás Monardes Programme, Consejería de Salud-SAS (Junta de Andalucía)

Influence of Food Matrices and the Population of Interfering Microorganisms on the Determination of Listeria monocytogenes by Conventional Methods and VIDAS

In this study, the possible influence of the food matrix and the interfering population of microorganisms on the detection and count of Listeria monocytogenes in three common foods of the Spanish diet (Spanish omelette, fresh cheese and vegetable salad) was determined. Four groups were assayed: one control, two groups with interfering microorganisms (Salmonella Enteritidis, Staphylococcus aureus and Proteus mirabilis) with different levels of L. monocytogenes and a final group only contaminated with L. monocytogenes. The samples were analyzed with the normalized method (UNE-EN ISO 11290:2018) and with an alternative technique (VIDAS). The results show that the presence of interfering microorganisms did not seem to interfere with the determination of L. monocytogenes. Furthermore, the type of food did not seem to influence the determination of L. monocytogenes, but the culture media used showed differences. In fact, regardless of the type of food, the ALOA medium showed higher sensitivity than the other media, with higher recovery in 100% of samples (only for the Spanish omelette in Group B was the result the same as that for PALCAM, −8.11 log cfu/g). The results obtained using the VIDAS were not influenced by any of the factors or conditions used and show 100% efficiency

In vascular smooth muscle cells paricalcitol prevents phosphate-induced Wnt/β-catenin activation

The present study investigates the differential effect of two vitamin D receptor agonists, calcitriol and paricalcitol, on human aortic smooth muscle cells calcification in vitro. Human vascular smooth muscle cells were incubated in a high phosphate (HP) medium alone or supplemented with either calcitriol 10−8M (HP + CTR) or paricalcitol 3·10−8 M (HP + PC). HP medium induced calcification, which was associated with the upregulation of mRNA expression of osteogenic factors such as bone morphogenetic protein 2 (BMP2), Runx2/Cbfa1, Msx2, and osteocalcin. In these cells, activation of Wnt/β-catenin signaling was evidenced by the translocation of β-catenin into the nucleus and the increase in the expression of direct target genes as cyclin D1, axin 2, and VCAN/versican. Addition of calcitriol to HP medium (HP + CTR) further increased calcification and also enhanced the expression of osteogenic factors together with a significant elevation of nuclear β-catenin levels and the expression of cyclin D1, axin 2, and VCAN. By contrast, the addition of paricalcitol (HP + PC) not only reduced calcification but also downregulated the expression of BMP2 and other osteoblastic phenotype markers as well as the levels of nuclear β-catenin and the expression of its target genes. The role of Wnt/β-catenin on phosphate- and calcitriol-induced calcification was further demonstrated by the inhibition of calcification after addition of Dickkopf-related protein 1 (DKK-1), a specific natural antagonist of the Wnt/β-catenin signaling pathway. In conclusion, the differential effect of calcitriol and paricalcitol on vascular calcification appears to be mediated by a distinct regulation of the BMP and Wnt/β-catenin signaling pathways

Wrapping of Microparticles by Floppy Lipid Vesicles

Lipid membranes, the barrier defining living cells and many of their sub-compartments, bind to a wide variety of nano- and micro-meter sized objects. In the presence of strong adhesive forces, membranes can strongly deform and wrap the particles, an essential step in crossing the membrane for a variety of health and disease-related processes. A large body of theoretical and numerical work has focused on identifying the physical properties that underly wrapping. Using a model system of micron-sized colloidal particles and giant unilamellar lipid vesicles with tunable adhesive forces, we measure a wrapping phase diagram and make quantitative comparisons to theoretical models. Our data is consistent with a model of membrane-particle interactions accounting for the adhesive energy per unit area, membrane bending rigidity, particle size, and vesicle radius

On-line surveys application to develop open choice and correlated food internships

Se han desarrollado encuestas on-line en diferentes asignaturas que tenían el uso de este tipo de herramientas como elementos de apoyo para el desarrollo de alguna de sus competencias. En función de los conocimientos previos de los alumnos y el nivel de formación, la implementación de las encuestas ha requerido una implicación más o menos profunda de los alumnos. En este sentido el grado máximo de implicación se ha realizado en la asignatura Nutrición Aplicada del Grado en Ciencia y Tecnología de los Alimentos, en el que los alumnos han decido e implementado absolutamente todos los aspectos inherentes a la encuesta (supervisado por los profesores). El resultado docente ha sido muy satisfactorio, cubriendo en cada asignatura una o varias competencias transversales y obviamente las específicas relativas al tema de la encuesta. El grado de satisfacción de los alumnos también ha sido elevado. Además la información recopilada tiene un elevado interés en cuanto a conocer aspectos relacionados con la forma de alimentarse de diferentes colectivos.On line-surveys were developed in several subjects which employ this kind of tools in order to achieve some of its competences. The implementations of surveys were made in different degrees according with the previous level of knowledge of the students. In this way, students of the subject “Nutrición Aplicada” which belong from the Degree of “Ciencia y Tecnología de Alimentos”, achieved the highest level of implication, developing all the items of the surveys (with supervision of their professors). The educational results were very satisfactory, covering all the transversal and specific competences of multiple subjects. The satisfaction level of the students was also very high. Furthermore, relevant information about dietetic habits of different population groups was obtained

Dietary Mg Supplementation Decreases Oxidative Stress, Inflammation, and Vascular Dysfunction in an Experimental Model of Metabolic Syndrome with Renal Failure

whether a dietary Mg supplementation might attenuate vascular dysfunction through the modulation of oxidative stress and inflammation in concurrent MetS and CKD. Methods: A rat model of MetS (Zucker strain) with CKD (5/6 nephrectomy, Nx) was used. Nephrectomized animals were fed a normal 0.1%Mg (MetS+Nx+Mg0.1%) or a supplemented 0.6%Mg (MetS+Nx+Mg0.6%) diet; Sham-operated rats with MetS receiving 0.1%Mg were used as controls. Results: As compared to controls, the MetS+Nx-Mg0.1% group showed a significant increase in oxidative stress and inflammation biomarkers (lipid peroxidation and aortic interleukin-1b and -6 expression) and Endothelin-1 levels, a decrease in nitric oxide and a worsening in uremia and MetS associated pathology as hypertension, and abnormal glucose and lipid profile. Moreover, proteomic evaluation revealed changes mainly related to lipid metabolism and CVD markers. By contrast, in the MetS+Nx+Mg0.6% group, these parameters remained largely similar to controls. Conclusion: In concurrent MetS and CKD, dietary Mg supplementation reduced inflammation and oxidative stress and improved vascular function

Use of ICT for autonomous learning in Food Science and Technology and Veterinary degrees in the University of Cordoba pilot plan

Con la finalidad de dotar a los estudiantes de los últimos cursos de los grados de Ciencia y Tecnología de los Alimentos y Veterinaria de las herramientas necesarias para fomentar el aprendizaje autónomo en instalaciones como la Planta Piloto de la Universidad de Córdoba (PPTA) se programaron diferentes actividades encaminadas a la recopilación de información sobre las instalaciones y equipos, realización de experimentos y desarrollo de trabajo fin de grado, de forma que se integrara en una página web propia, con información suficiente para que los estudiantes puedan formarse autónomamente mediante la consulta y el manejo de documentación generada a partir del uso de diferentes equipos o de las diferentes líneas de procesado, integrando materiales preparados a partir de la experiencia propia en la misma instalación tales como manuales, videos, fotografía de maquinaria y protocolos de experimentos.With the purpose of equipping the students of the last courses of Food Science and Technology and Veterinary degrees with the necessary tools to promote autonomous learning in facilities such as the Pilot Plant of the University of Córdoba, different activities were planned aimed at the collection of information on facilities and equipment, conducting experiments and developing end-of-degree work, so that it can be integrated into a web page of its own, with sufficient information so that students can be formed autonomously through consultation and documentation management generated from the use of different equipment or different processing lines, integrating materials prepared from their own experience in the same installation such as manuals, videos, machinery photography and experimental protocols