Vasquez-Murrieta M.S.,Escuela Nacional |
Patino-Siciliano A.,Laboratory of Plant Ecology |
Bioresource Technology | Year: 2010
Metal concentrations were measured in plants growing on heavily contaminated tailings from a mine active since about 1800 in San Luis Potosí (Mexico). Viguiera dentata (Cav.) Spreng., Parthenium bipinnatifidum (Ort.) Rollins, Flaveria angustifolia (Cav.) Pers., F. trinervia (Spreng.) C. Mohr. and Sporobolus indicus (L.) R. Br. were tolerant to high As, Cu, Pb and Zn concentrations. Of those, S. indicus excluded heavy metals from its shoots, while P. bipinnatifidum and F. angustifolia accumulated them. V. dentata and P. bipinnatifidum were accumulators of As, but not hyperaccumulators. It was found that V. dentata, P. bipinnatifidum, F. angustifolia, F. trinervia and S. indicus, could be used to vegetate soils contaminated with As, Cu, Pb and Zn. Ambrosia artemisifolia could be used to remediate soils contaminated with Zn, S. amplexicaulis those with Cu and F. angustifolia and F. trinervia those with As, as they have a strong capacity to accumulate those metals. © 2010 Elsevier Ltd. All rights reserved.
Sanchez-Torres L.E.,Escuela Nacional |
Torres-Martinez J.A.,Escuela Nacional |
Godinez-Victoria M.,Escuela Nacional |
Omar J.-M.,National Autonomous University of Mexico |
Velasco-Bejarano B.,National Autonomous University of Mexico
Phytomedicine | Year: 2010
In this study, we investigated the cytotoxic effect of perezone, a constituent isolated from the roots of Perezia spp. and of its synthetic isomer isoperezone on the K562 human leukemia cell line. Perezone showed greater cytotoxic effect than isoperezone but both compounds were found to induce cytotoxicity trough a caspase-dependent and a caspase-independent mechanisms; important changes in their light scattering properties, phosphatidylserine translocation and mitochondrial membrane potential disruption were detected by cytometry. The mechanism of death induction of each compound showed interesting concentration-dependent differences. Neither compound induced the apoptosis inducing factor. © 2009 Elsevier GmbH. All rights reserved.
Salinas-Moreno Y.,Escuela Nacional |
Ager A.,U.S. Department of Agriculture |
Vargas C.F.,Escuela Nacional |
Hayes J.L.,U.S. Department of Agriculture |
Zuniga G.,Escuela Nacional
Forest Ecology and Management | Year: 2010
Bark beetles of the genus Dendroctonus are natural inhabitants of forests; under particular conditions some species of this genus can cause large-scale tree mortality. However, only in recent decades has priority been given to the comprehensive study of these insects in México. México possesses high ecological diversity in Dendroctonus-Pinus associations. The geographic coexistence of 12 Dendroctonus species suggests greater vulnerability or threat of tree mortality relative to other areas. We use a biogeographic strategy to identify and rank the areas most vulnerable to tree mortality caused by bark beetles in México. We aim to define the areas that might experience high impact by these insects and also to provide a geographic database useful to forest resource management and conservation policies in México. Using collection records of bark beetles and pines, we develop a quantitative estimate of the threat of beetle infestation of forest areas based on factors including pine and beetle species density, host preference and level of mortality caused by beetle species. A quantitative estimate of forest area vulnerability, the Bark Beetle Threat Index (BBTI) was calculated. Despite the vast area of geographic coincidence of Pinus and Dendroctonus in México, the regions of highest bark beetle pressure are restricted to small zones within some mountain systems. The region that has been most affected by this insect group during the past hundred years is the Transverse Volcanic Belt, followed by the Sierra Madre Occidental and Sierra Madre del Sur. Pine diversity is the major determining factor of BBTI at the regional level, while disturbances from extensive logging and ecosystem change are the key factors behind high BBTIs at the local level. © 2010 Elsevier B.V.