Background: Skeletal muscle is one of the tissues most affected by stress conditions. The protein degradation in this tissue is vital for the supply of energy mediated by different proteolytic pathways such as the ubiquitinproteasome (UPS), autophagy-lysosome (ALS) and the calpain/calpastatin system (CCS). Nevertheless, the regulation of this proteolytic axis under stress conditions is not yet completely clear. Chile is the main producer of rainbow trout (Oncorhynchus mykiss) in the world. This intensive fish farming has resulted in growing problems as crowding and stress are one of the major problems in the freshwater stage. In this context, we evaluated the crowding effect in juvenile rainbow trout kept in high stocking density (30 kg/m 3) for 15, 45 and 60 days, using a control group of fish (10 kg/m 3). Results: Plasmatic cortisol and glucose were evaluated by enzyme immunoassay. The mRNA levels of stress-related genes (gr1, gr2, mr, hsp70, klf15 and redd1), markers of the UPS (atrogin1 and murf1) and CCS (capn1, capn1, cast-l and casts) were evaluated using qPCR. ALS (LC3-I/II and P62/SQSTM1) and growth markers (4E-BP1 and ERK) were measured by Western blot analysis. The cortisol levels increased concomitantly with weight loss at 45 days of crowding. The UPS alone was upregulated at 15 days of high stocking density, while ALS activation was observed at 60 days. However, the CCS was inactivated during the entire trial. Conclusion: All these data suggest that stress conditions, such as crowding, promote muscle degradation in a time-dependent manner through the upregulation of the UPS at early stages of chronic stress and activation of the ALS in long-term stress, while the CCS is strongly inhibited by stress conditions in the rainbow trout muscle farmed during freshwater stage. Our descriptive study will allow perform functional analysis to determine, in a more detailed way, the effect of stress on skeletal muscle physiology as well as in the animal welfare in rainbow trout. Moreover, it is the first step to elucidate the optimal crop density in the freshwater stage and improve the standards of Chilean aquaculture.

Los medios de comunicación a partir de la implementación de las nuevas Tecnologías de la Información y Comunicación (TIC) se han diversificado conforme a la evolución y adaptación del uso de dispositivos tecnológicos en la vida del hombre. Con la hibridación de los medios surge la ecología mediática en la cual emergen nuevas formas de llevar acabo el acto comunicativo, los medios de comunicación se adaptan a la prácticas comunicativas y en ello se condensan las nuevas formas de comunicar. Estudiar el alcance y los niveles significativos de los modelos convergentes en los procesos de comunicación digital no sólo nos acercan al panorama mediático también nos vislumbra las capacidades de las plataformas y los dispositivos en el contexto social. En el siguiente documento discutiremos como a partir de la implementación de herramientas digitales y las narrativas transmedia podemos generar un aporte significativo a la apropiación del conocimiento por parte de los usuarios. Mediante el reconocimiento de los niveles de significación de todos los actores involucrados en la comunidad, entenderemos como las dinámicas participativas y colaborativas nos acercan a la democratización del conocimiento. Para comprender tanto el proceso apropiación del conocimiento como la relación que existe entre la sociedad y la tecnología es necesario definir de manera conceptual el proceso de apropiación, posteriormente el ecosistema mediático en el que se vinculan la narrativas mediáticas, para así abordar la relación que existe entre la tecnología digital, las narrativas transmedia y los procesos de apropiación del conocimiento en los usuarios.

Critical valve diseases in infants have a very poor prognosis for survival. Particularly challenging is for the valve replacement to support somatic growth. From a valve regenerative standpoint, bio-scaffolds have been extensively investigated recently. While bio-scaffold valves facilitate acute valve functionality, their xenogeneic properties eventually induce a hostile immune response. Our goal was to investigate if a bio-scaffold valve could be deposited with tissues derived from allogeneic stem cells, with a specific dynamic culture protocol to enhance the extracellular matrix (ECM) constituents, with subsequent stem cell removal. Porcine small intestinal submucosa (PSIS) tubular-shaped bio-scaffold valves were seeded with human bone marrow-derived mesenchymal stem cells (hBMMSCs), cultured statically for 8 days, and then exposed to oscillatory fluid-induced shear stresses for two weeks. The valves were then safely decellularized to remove the hBMMSCs while retaining their secreted ECM. This de novo ECM was found to include significantly higher (p < 0.05) levels of elastin compared to the ECM produced by the hBMMSCs under standard rotisserie culture. The elastin-rich valves consisted of ~8% elastin compared to the ~10% elastin composition of native heart valves. Allogeneic elastin promotes chemotaxis thereby accelerating regeneration and can support somatic growth by rapidly integrating with the host following implantation. As a proof-of-concept of accelerated regeneration, we found that valve interstitial cells (VICs) secreted significantly more (p < 0.05) collagen on the elastin-rich matrix compared to the raw PSIS bio-scaffold.

No abstract