Ciencias de la Biología y Agronomía

Este volumen I contiene 17 capítulos arbitrados que se ocupan de estos asuntos en Tópicos Selectos de Ciencias de la Biología y Agronomía, elegidos de entre las contribuciones, reunimos algunos investigadores y estudiantes. Se presenta un Estudio Comparativo de los Recursos Hidrológico-Forestales de la Microcuenca de la Laguna de Epatlan, Pue. (1993 a 2014); la Situación Actual de la Mancha de Asfalto en Maíz (Zea mays L.) en los Municipios de Jiquipilas y Ocozocoautla, Chiapas, México; las poblaciones sobresalientes de maíz de la raza Zapalote Chico, en la Región Istmeña de Oaxaca; Se indica el índice de área foliar de cultivo de Chile Poblano mediante dos métodos en condiciones protegidas; Esquivel, Urzúa y Ramírez exploran el efecto de la biofertilización con Azospirillum en el crecimiento y producción de Jitomate; esbozan su artículo sobre la determinación del nivel de Heterosis en híbridos de Maíz para la Comarca Lagunera; una investigación sobre la estabilización de semilla de Solanum lycopersicum durante el almacenamiento y estimulación de la germinación; acotan sobre el CTAB como una nueva opción para la detección de Huanglongbing en cítricos, plantean su evaluación sobre el aluminio y cómo afecta la vida de florero de Heliconia psittacorum; indican sobre el impacto del H-564C, como un híbrido de maíz con alta calidad de proteina para el trópico húmedo de México; presetan su investigación sobre la producción de Piña Cayena Lisa y MD2 (Ananas comosus L.) en condiciones de Loma Bonita, en Oaxaca; acotan sobre el efecto de coberteras como control biológico por conservación contra áfidos en Nogal Pecanero; esbozan sobre la caracterización de cuatro genotipos de Frijol Negro en Martínez de la Torre, Veracruz, México; presentan una caracterización hidroecológica de la microcuenca de Arroyo Prieto, Yuriría, Gto., y alternativas para su restauración ambiental; presentan su investigación sobre el efecto del hongo Beauveria bassiana sobre solubilización de fosfatos y la disponibilidad de fósforo en el suelo; plantean su investigación sobre la Germinación y regeneración in vitro de Epidendrum falcatum LINDL; esbozan su artículo sobre genotipos de frijol negro y su tolerancia a sequía terminal en Veracruz, México

Potential of wind erosion and dust emission in an arid zone of northern Mexico: A simple assessment method

Wind erosion is the main problem that arid lands in northern Mexico are facing. Quantification of this phenomenon is crucial for planning purposes and to scale its impact. The challenge is to assess the problem under limited availability of climatic information. This study aimed to identify potential areas of dust emissions in an arid zone of Northern Mexico. Wind direction and intensity were characterized through a robust index that involves rainfall and evaporation as well as the climatic factor of the general wind erosion equation. A method for assessing the likelihood of dust emission associated with wind erosion was applied. Data from twelve weather stations within the region of the study was analyzed. The variables considered were wind velocity and direction, temperature, and precipitation. A wind rose of wind direction and intensity was obtained. Results showed that the Thornthwaite’s method for computing the Soil Moisture Index (SMI) is a good approach when computing the climatic factor C of the general function of the potential average annual soil loss. Given the lack of local evaporation data, the precipitation-evaporation ratio ( P E ) for each weather station was computed as an intermediate step towards the computation of C. Three of the analyzed climatic stations had intermediate C values (36-71 %) in the scale of wind erosion climatic factor. The wind velocities registered in these climatic stations ranged from 15 to 30 km h-1. The magnitude-frequency analysis of the P E parameter for the stations showed the differences in rainfall and evaporation regimes. Dust pollution prone areas were identified, showing areas where conservation strategies should be directed

On the Oxidative Damage by Cadmium on Kidney Mitochondrial Functions

In the kidney, the accumulation of heavy metals, such as Cd2+, produce mitochondrial dysfunctions, i.e., uncoupling of the oxidative phosphorylation, inhibition of the electron transport through the respiratory chain, and collapse of the transmembrane electrical gradient. This derangement may be due to the fact that Cd2+ induces the transition of membrane permeability from selective to non-selective via the opening of a transmembrane pore. In fact, Cd2+ produces this injury through the stimulation of oxygen-derived radical generation conducing to oxidative stress. Several molecules have been used to avoid or even reverse the Cd2+-induced mitochondrial injury, for instance, cyclosporin A, resveratrol, dithiocarbamates, and even EDTA. The aim of the present study was to explore the possibility that tamoxifen, an antioxidant reagent, may preserve mitochondrial function from the deleterious effects of Cd2+. Our results indicate that addition of 1 ÎźM Cd2+ to mitochondria collapsed the transmembrane electrical gradient, induced the release of cytochrome c, and increased both the generation of H2O2 and the oxidative damage to mitochondrial DNA (among other measured parameters). Of interest, these mitochondrial dysfunctions were ameliorated after the addition of tamoxifen.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Uncovered contribution of Kv7 channels to pulmonary vascular tone in pulmonary arterial hypertension

K+channels play a fundamental role regulating membrane potential of pulmonary artery (PA) smooth muscle cells and their impairment is a common feature in pulmonary arterial hypertension (PAH). K+voltage-gated channel subfamily Q (KCNQ1-5) or Kv7 channels and their regulatory subunits subfamily E (KCNE) regulatory subunits are known to regulate vascular tone, but whether Kv7 channel function is impaired in PAH and how this can affect the rationale for targeting Kv7 channels in PAH remains unknown. Here, we have studied the role of Kv7/KCNE subunits in rat PA and their possible alteration in PAH. Using the patch-clamp technique, we found that the total K+current is reduced in PA smooth muscle cells from pulmonary hypertension animals (SU5416 plus hypoxia) and Kv7 currents made a higher contribution to the net K+current. Likewise, enhanced vascular responses to Kv7 channel modulators were found in pulmonary hypertension rats. Accordingly, KCNE4 subunit was highly upregulated in lungs from pulmonary hypertension animals and patients. Additionally, Kv7 channel activity was enhanced in the presence of Kv1.5 and TASK-1 channel inhibitors and this was associated with an increased KCNE4 membrane abundance. Compared with systemic arteries, PA showed a poor response to Kv7 channel modulators which was associated with reduced expression and membrane abundance of Kv7.4 and KCNE4. Our data indicate that Kv7 channel function is preserved and KCNE4 is upregulated in PAH. Therefore, compared with other downregulated channels, the contribution of Kv7 channels is increased in PAH resulting in an enhanced sensitivity to Kv7 channel modulators. This study provides insight into the potential usefulness of targeting Kv7 channels in PAH

Baja prevalencia de la infección por el virus de la hepatitis C en una población de reclusos, Maracaibo, Venezuela

Introducción. Las conductas de alto riesgo presentes en los centros de reclusión incrementan la probabilidad de transmisión de la infección por el virus de la hepatitis C. En Venezuela no se han realizado estudios del virus en estos centros, por lo que se desconoce la relevancia de la infección en ellos. Objetivo. Estimar la prevalencia del virus de la hepatitis C y los posibles factores de riesgos involucrados en la transmisión del virus en reclusos de la cárcel de Sabaneta, Maracaibo, Venezuela. Material y métodos. Se seleccionó una población de 200 reclusos de un total de 1.000. Las edades estaban comprendidas entre 18 y 69 años (media ± DE: 31,62±9,93 años). La detección de anticuerpos contra el virus de la hepatitis C se realizó por duplicado mediante el método inmunoenzimático ELISA de IV generación y por el método de inmunoblot INNO-LIA HCV®, ambos de Innogenetic Lab (Bélgica). El ARN viral se detectó por la técnica de reacción en cadena de la polimerasa, previa transcripción inversa, RT-PCR. Resultados. La frecuencia obtenida con el método ELISA fue de 5% (10/200) y 3/200 (1,5%) individuos fueron positivos, a la vez, con los métodos de INNO-LIA y RT-PCR. Conclusiones. La prevalencia de la infección por el virus de la hepatitis C en esta población fue baja, lo que evidencia la baja circulación del virus en el reclusorio. El principal factor de riesgo para la adquisición de la infección, al parecer, es el uso de drogas intravenosas