De las actividades acuícolas, la producción en estanques tiene una gran importancia en los países como Brasil, Colombia y Venezuela, entre otros, en donde las cifras de producción presentan un panorama de crecimiento acelerado. La piscicultura, por ejemplo, tiene un enorme potencial debido a las óptimas condiciones de nuestros países en cuanto a hidrología, topografía y edafología, y por la riqueza en especies ícticas con cualidades para cultivo. Así, la piscicultura se torna una actividad agropecuaria autóctona y ventajosa. Trabajar con riquezas naturales propias permite ventajas competitivas, minimizando costos, y reduciendo necesidades de importar insumos y tecnología, entre otras. Observamos que otras actividades agropecuarias se sustentan en especies importadas y adaptadas a las más adversas condiciones, como ejemplo, el ganado europeo, el arroz chino, etc. Sin embargo, se debe reconocer que desarrollar tecnologías de producción obliga a considerar aspectos ambientales que garanticen su permanencia en el tiempo, con beneficios sociales, económicos, etc. La acuicultura como cualquier actividad genera impacto, empezando porque se desarrolla en ecosistemas artificiales diferentes a los naturales, y afectando los recursos hídricos por la cantidad de efluentes ricos en materia orgánica, que son vertidos sin siquiera saber lo que está siendo lanzado. Este artículo presenta una revisión de la actividad, los diferentes tipos de impactos generados y algunas alternativas biológicas para el tratamiento de los efluentes, buscando herramientas para alcanzar una acuicultura responsable.
Riboflavin, vitamin B2, is essential for humans and has to be obtained from the diet. Some lactic acid bacteria (LAB) produce this vitamin, and they can be used for in-situ fortification of foods. This could be an alternative to supplementation with chemically synthesized vitamin, to palliate riboflavin deficiencies in specific groups of people. Moreover, if the producing LAB could survive in the gastrointestinal stress (GIT) they could be added as probiotics in this environment. In the present study we tested two riboflavin-overproducing Lactiplantibacillus plantarum strains (M5MA1-B2 and M9MG6-B2), spontaneous mutants of LAB isolated from chicha, a traditional Andean beverage. These two LAB, and also their isogenic strains M5MA1-B2[pRCR12] and M9MG6-B2[pRCR12], expressing the mCherry protein from the pRCR12 plasmid, were evaluated in vitro under simulated GIT conditions. Among other, specifically developed protein fluorescence assays were used. The four LAB showed similar levels of adhesion (>6.0%) to Caco-2 cells, higher than that of the probiotic Lacticaseibacillus rhamnosus GG strain (4.51%). Thus, LAB biofilm formation was assessed in the labeled cells by intracellular mCherry fluorescence and in the unlabeled parental strains by crystal violet staining. Both methods detected the formation of consistent biofilms by the L. plantarum strains. The quantification of mCherry fluorescence was also used to analyze LAB auto-aggregation properties. High levels of auto-aggregation were detected for both M5MA1-B2[pRCR12] and M9MG6-B2[pRCR12]. Survival of LAB included in a commercial cereal-based food matrix (Incaparina) under GIT conditions was also evaluated. The four LAB were resistant in vitro to the stomach and intestinal stresses, and proliferated in this environment, indicating a protective and nutritional effect of the Incaparina on the bacteria. Also, M9MG6-B2 survival in the presence or absence of Incaparina was evaluated in vivo in a BALB/c mouse model. The administration of the M9MG6-B2 strain alone or together with Incaparina had no Hernández-Alcántara et al. Riboflavin-Overproducing Lactiplantibacillus Plantarum Gastrointestinal Survival adverse effect on the health, growth and/or well-being of the rodents. In addition, an increment in the villus length/crypt depth ratio was observed. The overall results obtained indicate that the LAB studied have probiotic characteristics of interest for the development of functional foods.
Melanoma is the deadliest form of skin cancer showing rising incidence over the past years. New insights into the mechanisms of melanoma progression contributed to the development of novel treatment options, such as immunotherapies. However, acquiring resistance to treatment poses a big problem to therapy success. Therefore, understanding the mechanisms underlying resistance could improve therapy efficacy. Correlating expression levels in tissue samples of primary melanoma and metastases revealed that secretogranin 2 (SCG2) is highly expressed in advanced melanoma patients with poor overall survival (OS) rates. By conducting transcriptional analysis between SCG2-overexpressing (OE) and control melanoma cells, we detected a downregulation of components of the antigen presenting machinery (APM), which is important for the assembly of the MHC class I complex. Flow cytometry analysis revealed a downregulation of surface MHC class I expression on melanoma cells that showed resistance towards the cytotoxic activity of melanoma-specific T cells. IFNγ treatment partially reversed these effects. Based on our findings, we suggest that SCG2 might stimulate mechanisms of immune evasion and therefore be associated with resistance to checkpoint blockade and adoptive immunotherapy.
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