Integrating stress signals at the endoplasmic reticulum: The BCL-2 protein family rheostat

AbstractThe assembling of distinct signaling protein complexes at the endoplasmic reticulum (ER) membrane controls several stress responses related to calcium homeostasis, autophagy, ER morphogenesis and protein folding. Diverse pathological conditions interfere with the function of the ER altering protein folding, a condition known as “ER stress”. Adaptation to ER stress depends on the activation of the unfolded protein response (UPR) and protein degradation pathways such as autophagy. Under chronic or irreversible ER stress, cells undergo apoptosis, where the BCL-2 protein family plays a crucial role at the mitochondria to trigger cytochrome c release and apoptosome assembly. Several BCL2 family members also regulate physiological processes at the ER through dynamic interactomes. Here we provide a comprehensive view of the roles of the BCL-2 family of proteins in mediating the molecular crosstalk between the ER and mitochondria to initiate apoptosis, in addition to their emerging functions in adaptation to stress, including autophagy, UPR, calcium homeostasis and organelle morphogenesis. We envision a model where BCL-2-containing complexes may operate as stress rheostats that, beyond their known apoptosis functions at the mitochondria, determine the amplitude and kinetics of adaptive responses against ER-related injuries. This article is part of a Special Issue entitled Mitochondria: the deadly organelle

Estudio y comparación de bases de datos orientadas a grafos

90 p.Un grafo es básicamente un conjunto de puntos (vértices) en el espacio, que están conectados por un conjunto de líneas (aristas). Como una de las formas más generales de modelado de datos, un grafo permite representar fácilmente entidades, sus atributos y sus relaciones.Las Bases de Datos Orientadas a Grafos (BDOG) se caracterizan porque las estructuras de datos para el esquema e instancia se basan en modelos de datos de grafo.Estos modelos se iniciaron en los años ochenta y a principios de los noventa, junto con modelos orientados a objetos. Su influencia decayó poco a poco con la aparición de nuevos modelos de bases de datos. Recientemente, la necesidad de gestionar la informacióon a través de una estructura de grafo y las limitaciones de las bases de datos tradicionales (en particular el modelo relacional), para cubrir las necesidades de las aplicaciones actuales ha llevado al desarrollo de nuevas tecnologías, y por consiguiente ha restablecido la importancia de esta área. El objetivo principal de este estudio es realizar una comparación sistematica de bases de datos de grafo.En este trabajo se presenta una revisión de las bases de datos de grafo actuales y su comparación de acuerdo a algunas caracterìsticas de modelado de datos. Entre las características evaluadas se incluyen: almacenamiento de datos, representación de entidades y relaciones, operación y manipulación de datos (lenguajes de consulta de grafos e interfaces de programación), y restricciones de integridad. Adicionalmente,se presenta una evaluaciçon empírica basada en pruebas de carga y consulta de datos. Este trabajo permite conocer y comparar, de manera teórica y práctica,las capacidades de modelado y ejecución entregadas por cada base de datos de grafo./ABSTRACT: A graph is basically a set of points (vertices) in space, which are connected by a set of lines (edges). As one of the most general forms of data modeling, a graph easily allows the representation of entities, their attributes and their relationships. Graph-oriented Databases (GODB) are characterized because their data structures for the scheme and instance are based on graph data models. These models began in the eighties and early nineties, along with object-oriented models. Their influence gradually faded with the emergence of new models of databases. Recently, the need to manage information through a graph structure and the limitations of traditional databases (in particular the relational model), to meet the needs of current applications has led to the development of new technologies, and therefore restored the importance of this area. The main objective of this study is to perform a systematic comparison of graph databases. This work presents a review of the current graph databases and their comparison according to well-defined data modeling features. Among the evaluated features we include: data storage, representation of entities and relationships, data operation and manipulation (graph query languages and application programming interfaces), and integrity constraints. Additionally, we present an empirical evaluation based on load and query data testing. This work allows to know and compare, from a theoretical and practical point of view, the modeling and execution capabilities provided by each graph database

Karyotype and C-bands in the annual inca lily Alstroemeria graminea

Alstroemeria graminea Phil. (Taltalia graminea according to BAYER 1998) is the only annual species described within the genus Alstroemeria L. and its cytogenetic relationship with the perennial species have not been described. In this work, an analysis of the karyotype and the C-banding pattern of Alstroemeria graminea are reported. A. graminea, with an asymmetric karyotype 2n = 2x = 16, shows similar chromosome morphology with respect to the perennial Alstroemeria species previously analysed. However, some differences in relative length and position of the C-bands were observed in A. graminea. These differences were the presence of a centromeric band and an interstitial band in the short arm of pair 1 and pericentromeric bands in the long arms of pairs 3 and 7, which have not been observed in the other species. The cytogenetic data of the present study on A. graminea are concurrent with other species within the genus Alstroemeria, and do not justify the separation of this species from the genus Alstroemeria and its inclusion in the new monotypic genus Taltalia