Efecto del cambio de uso de suelo sobre las propiedades edáficas en la sabana, Huimanguillo, Tabasco, México

Objective: Evaluate physical and chemical properties of acid soils subject to change of land use in La Sabana of Huimanguillo, Tabasco, México. Design/methodology/approach: The following technical criteria were used: production systems representative of savanna soils in Huimanguillo, Tabasco, from sugar cane (Saccharum spp.), pineapple (Ananas comosus L.), cassava (Manihot esculenta Crantz), pastureland, and acahual (secondary vegetation). Physical and chemical properties were evaluated using standardized methods: apparent density (AD), organic matter (OM), total nitrogen (N), extractable phosphorus (P Olsen), cation exchange capacity (CEC), electric conductivity (EC), exchangeable bases (K, Ca and Mg), and pH. Results: Results suggest highly statistical differences in contents of OM, AD, pH, and porosity (%). Statistical differences were found in Ca, Mg, and K content. Total N, P Olsen, CEC and EC, did not show statistical differences. Study limitations/implications: La Sabana of Huimanguillo, has been affected by a significant loss of soil fertility, therefore is important to evaluate the soil degradation process by change of land use under different climate conditions. Findings/conclusions: Evaluation of soil properties degradation in acid soils subject to different land use, physical and chemical properties of soils showed that sugar cane and pastureland were affected significantly.Objetivo: Evaluar las propiedades físicas y químicas de suelos ácidos de La Sabana de Huimanguillo, Tabasco, México, sujetos a diferentes usos. Diseño/metodología/aproximación: Se consideraron los siguientes criterios técnicos, sistemas de producción representativos de sabana en el municipio de Huimanguillo que corresponden a caña de azúcar (Saccharum spp.), piña (Ananas comosus L.), yuca (Manihot esculenta Crantz), pastizal y acahual. Se evaluaron las propiedades físicas y químicas a través de métodos estandarizados: densidad aparente (Dap), materia orgánica (MO), nitrógeno (N) total, fósforo (P Olsen) extractable, capacidad de intercambio catiónico (CIC), conductividad eléctrica (CE), bases intercambiables (K, Ca y Mg) y pH. Resultados: Se obtuvieron resultados altamente significativos para MO, DAP, pH y Porosidad %, en los contenidos de Ca, Mg, y K se encontraron diferencias significativas, en cambio con N total, P Olsen, CIC y CE no se observaron diferencias significativas. Limitaciones del estudio/implicaciones: La Sabana de Huimanguillo, se ha visto afectada por la pérdida significativa de la fertilidad en suelo, por lo que es necesario evaluar el proceso de degradación en un periodo de mayo a diciembre, contemplando las condiciones climáticas (seca-lluvia). Hallazgos/conclusiones: Al evaluar la degradación de las propiedades de los suelos ácidos sujetos a diferentes usos, el sistema de producción de caña de azúcar y el pastizal son los cultivos que más son afectados en las propiedades físicas y químicas de los suelos

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field