Role of geometrical cues in bone marrow-derived mesenchymal stem cell survival, growth and osteogenic differentiation

Mesenchymal stem cells play a vital role in bone formation process by differentiating into osteoblasts, in a tissue that offers not a flat but a discontinuous three-dimensional (3D) topography in vivo. In order to understand how geometry may be affecting mesenchymal stem cells, this study explored the influence of 3D geometry on mesenchymal stem cell-fate by comparing cell growth, viability and osteogenic potential using monolayer (two-dimensional, 2D) with microsphere (3D) culture systems normalised to surface area. The results suggested lower cell viability and reduced cell growth in 3D. Alkaline phosphatase activity was higher in 3D; however, both collagen and mineral deposition appeared significantly lower in 3D, even after osteogenic supplementation. Also, there were signs of patchy mineralisation in 3D with or without osteogenic supplementation as early as day 7. These results suggest that the convex surfaces on microspheres and inter-particulate porosity may have led to variable cell morphology and fate within the 3D culture. This study provides deeper insights into geometrical regulation of mesenchymal stem cell responses applicable for bone tissue engineering

Edible coating based on carnauba wax nanoemulsion and cymbopogon martinii essential oil on papaya postharvest preservation.

Papaya is a fruit of great importance worldwide. However, significant losses during postharvest have been reported, which can be minimized by applying lipid nanoemulsions as edible coatings associated with natural antimicrobial compounds. These coatings provide a barrier to gases and water vapor, in addition to improving mechanical properties, thereby delaying natural senescence and minimizing deterioration by phytopathogens during storage. The aim of this study was to investigate the preservation potential of papaya fruits treated with an edible coating based on an association between carnauba wax nanoemulsion (CWN) and Cymbopogon martinii essential oil (CEO). Coatings formulated with CWN and/or CEO were applied to papaya fruits, and resulted in late ripening during the 12-day storage period, without negatively affecting postharvest fruit quality parameters. The coatings reduced weight loss and maintained firmness, in addition to delaying changes in fruit color during storage. Coatings formulated with CWN + CEO were the most efficient formulations in reducing the incidence and severity of fruit rots during storage. CWN coatings incorporating CEO present additional functionalities in maintaining postharvest quality parameters of papaya fruits

Comparación de métodos para analizar materia orgánica en materiales orgánicos: Comparison of methods for analyzing organic matter in organic materials

Se compararon dos métodos (combustión húmeda y calcinación a 550 ºC) para la determinación de la materia orgánica en materiales orgánicos. En el ensayo participaron nueve laboratorios, empleando cinco materiales orgánicos (tres composts y dos sustratos), analizados por cuadruplicado. La precisión se evaluó calculando la repetibilidad y la reproducibilidad, según la norma COVENIN 2972-92 (ISO 5725-86). No se encontraron diferencias significativas entre métodos, laboratorios, ni réplicas, por lo que se asume que los métodos comparados generan resultados estadísticamente iguales. La precisión evaluada a través de la repetibilidad y la reproducibilidad no resultó dependiente del nivel de materia orgánica. Los menores valores de repetibilidad y reproducibilidad obtenidos con el método de calcinación indican que esta modalidad analítica es más precisa. Se recomienda la aplicación del método de calcinación porque se basa en un procedimiento rápido, sencillo, no consume reactivos químicos y no genera desechos tóxicos para el ambiente y la salud

FSP1 is a glutathione-independent ferroptosis suppressor

Ferroptosis is an iron-dependent form of necrotic cell death marked by oxidative damage to phospholipids1,2. To date, ferroptosis has been believed to be controlled only by the phospholipid hydroperoxide-reducing enzyme glutathione peroxidase 4 (GPX4)3,4 and radical-trapping antioxidants5,6. However, elucidation of the factors that underlie the sensitivity of a given cell type to ferroptosis7 is critical to understand the pathophysiological role of ferroptosis and how it may be exploited for the treatment of cancer. Although metabolic constraints8 and phospholipid composition9,10 contribute to ferroptosis sensitivity, no cell-autonomous mechanisms have been identified that account for the resistance of cells to ferroptosis. Here we used an expression cloning approach to identify genes in human cancer cells that are able to complement the loss of GPX4. We found that the flavoprotein apoptosis-inducing factor mitochondria-associated 2 (AIFM2) is a previously unrecognized anti-ferroptotic gene. AIFM2, which we renamed ferroptosis suppressor protein 1 (FSP1) and which was initially described as a pro-apoptotic gene11, confers protection against ferroptosis elicited by GPX4 deletion. We further demonstrate that the suppression of ferroptosis by FSP1 is mediated by ubiquinone (also known as coenzyme Q10 (CoQ10)): the reduced form, ubiquinol, traps lipid peroxyl radicals that mediate lipid peroxidation, whereas FSP1 catalyses the regeneration of CoQ10 using NAD(P)H. Pharmacological targeting of FSP1 strongly synergizes with GPX4 inhibitors to trigger ferroptosis in a number of cancer entities. In conclusion, the FSP1–CoQ10–NAD(P)H pathway exists as a stand-alone parallel system, which co-operates with GPX4 and glutathione to suppress phospholipid peroxidation and ferroptosis