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Genetic diversity of the Mycobacterium tuberculosis Complex in San Luis Potosí, México
Get PDF"Background Although epidemiologic and socioeconomic criteria and biomedical risk factors indicate high-priority for tuberculosis (TB) control in Mexico, molecular epidemiology studies of the disease in the country are scarce.
Methods Complete sociodemographic and clinical data were obtained from 248 of the 432 pulmonary TB (PTB) cases confirmed from 2006 to 2010 on the population under epidemiological surveillance in the state of San Luis Potosí, México. From most PTB cases with complete data Mycobacterium tuberculosis complex (MTC) isolates were recovered and their spoligotypes, lineages and families, geographic distribution and drug resistance determined.
Results Pulmonary tuberculosis incidence ranged from 2.4 to 33.4 (cases per 100,000 inhabitants) in the six state sanitary jurisdictions that were grouped in regions of low (jurisdictions I-II-III), intermediate (jurisdictions IV-V) and high incidence (jurisdiction VI) with 6.2, 17.3 and 33.4 rates, respectively. Most patients were poor, 50-years-median-age males and housewives. Among the 237 MTC spoligotyped isolates, 232 corresponded to M. tuberculosis (104 spoligotypes in 24 clusters) and five to M. bovis. The predominant Euro-American lineage was distributed all over the state, the East-Asian lineage (Beijing family) in the capital city, the Indo-Oceanic (Manila family) in eastern localities, and M. bovis in rural localities.
Conclusions In San Luis Potosí TB affects mainly poor male adults and is caused by M. tuberculosis and to a minor extent by M. bovis. There is great genotypic diversity among M. tuberculosis strains, the Euro-American lineage being much more prevalent than the Indo-Oceanic and East-Asian lineages. The frequency of resistant strains is relatively low and not associated to any particular lineage.
Origen de la calidad del agua del acuífero colgado y su relación con los cambios de uso de suelo en el Valle de San Luis Potosí
Get PDF"La historia de la ciudad San Luis Potosí se remonta al siglo XVI. Con el descubrimiento de yacimientos de oro y plata y la presencia de cuerpos de agua en el valle, fue fundada la ciudad San Luis Minas del Potosí, dando lugar a los dos primeros usos de suelo, urbano y minero. A partir del siglo XVII, el uso de suelo agrícola se desarrolló en huertos y fue relegado a la periferia de la zona urbana en el transcurso del tiempo. Finalmente el uso de suelo industrial surgió de manera importante en la segunda mitad del siglo XX. En la actualidad los tres usos de suelo existentes dentro del Valle de San Luis Potosí son el urbano, agrícola e industrial. A través de una campaña de muestreo hidrogeoquímico en octubre de 2008, con 44 muestras de norias y 3 de manantiales dentro del valle, se evaluaron parámetros físico-químicos, cationes, aniones y elementos traza. En los tres usos de suelo en la zona de estudio fueron detectados niveles importantes de nitratos, sulfatos, cloruros, conductividad eléctrica, coliformes totales y fecales; sin embargo, en la zona urbana existen anomalías puntuales de metales pesados principalmente de mercurio, bario, estroncio, cadmio, plomo, fósforo y plata, relacionadas a las antiguas actividades mineras y a la industria activa en la zona. Mientras que en la zona agrícola, la presencia de metales está asociada a los canales a cielo abierto que también reciben agua del Tanque Tenorio y éste a su vez de la zona industrial. En la zona industrial se detectaron grandes anomalías de tipo puntual en casi todos los metales pesados analizados; la principal fuente de estos contaminantes corresponden a un terreno industrial activo. Este trabajo está enfocado a evaluar el impacto que ha generado la actividad antropogénica sobre el acuífero colgado del Valle de San Luis Potosí desde inicios de la fundación de la ciudad hasta la actualidad, utilizando la calidad del agua como herramienta de análisis.""The history of San Luis Potosi City dates back to the sixteenth century. With the discovery of gold and silver deposits and the presence of water bodies in the valley, the city of San Luis Minas Potosí was founded, leading to the first two uses of land: urban and mining. From the seventeenth century, agricultural land developed in orchards and, over time, was relegated to the periphery of the urban area. Finally, industrial land use emerged significantly in the second half of the twentieth century. Currently the three existing land uses within the Valley of San Luis Potosi are urban, agricultural and industrial. Through a hydrogeochemical sampling campaign in October 2008 with 44 samples from wells and 3 from springs within the valley, we assessed physical and chemical parameters, cations, anions and trace elements. In the three land uses within the study area, we detected significant levels of nitrates, sulphates, chlorides, electrical conductivity, total and fecal coliforms; but in urban areas there are punctual anomalies of heavy metals, mainly mercury, barium, strontium, cadmium, lead, phosphorus and silver related to former mining and active industry in the area. However, in the agricultural zone, the presence of metals is associated with open channels, which also receive water from the Tanque Tenorio and this in turn from the industrial area. In the industrial area, puntual anomalies were detected in almost all heavy analyzed metals; the main source of these pollutants corresponds to an active industrial area. This work aims to evaluate the impact of anthropogenic activity in the perched aquifer of the Valley of San Luis Potosí since the city's foundation to the present, using water quality as an analytical tool.
Potential distributional patterns of three wild ungulate species in a fragmented tropical region of northeastern Mexico
Get PDF"In the northernmost American tropical forests of eastern Mexico, we analyzed the potential distribution of three ungulate species, Odocoileus virginianus, Mazama temama and Pecari tajacu, in response to several physical, climatic, biological, and anthropogenic variables, in order to identify environmental factors affecting distribution and potential key areas for ungulate conservation. Current presence records for these species were gathered, and potential distribution models were built using Maximum Entropy niche modeling (MaxEnt). Model suitability surfaces were used to calculate remaining potential habitat areas in the region, as well as the potential sympatric area and representation of these areas in Natural Protected Areas. Biological and anthropogenic variables were the best species distribution predictors. Landscape composition (the proportion of different land-use and land-cover classes: forest, agriculture, and pasture) within approximately 120 ha, was the most important variable for all models, influencing each species differently with respect to their tolerance of altered habitats. The remaining potential area of all three species is fragmented and has apparently been nearly lost in plains (<14% remaining). Distribution models allowed us to detect an important location in the western portion of our study area which may function as a large biological corridor in the Sierra Madre Oriental mastogeographic province, a region heavily transformed by land use change. In the context of habitat transformation, management promoting quality matrix at the landscape level promises to be a viable alternative for ungulate conservation in tropical regions of Mexico.
Germination, infestation, and viability in acorns of Quercus polymorpha (Schltdl. & Cham.) after 1-year storage
Get PDF"Los encinos blancos tienen semillas recalcitrantes que se mantienen viables por corto tiempo. Sin embargo, esta información es escasa para encinos mexicanos. Este es el caso de Quercus polymorpha, una especie tolerante a la sequía y ampliamente distribuida en la Sierra Madre Oriental que puede utilizarse en programas de restauración forestal. Las bellotas son colectadas durante la época reproductiva y son almacenadas por varios meses antes de su germinación. Este estudio se enfocó en 1) determinar cuántas semillas se pierden durante el almacenamiento debido a factores fisiológicos relacionados con su viabilidad, 2) cuantificar las semillas que se pierden por otros factores, y 3) evaluar si la estratificación fría puede estimular la germinación de las bellotas. Las bellotas utilizadas fueron almacenadas durante un año. El 70 % de las bellotas estaban parasitadas por insectos antes de su almacenamiento, mientras que el 20 % perdió su viabilidad debido a factores fisiológicos o infestación por hongos. Los ensayos de germinación se llevaron a cabo utilizando sólo bellotas potencialmente viables, las cuales fueron sometidas a tres periodos de estratificación en frío (0, 20 y 50 días). El experimento mostró que las bellotas estratificadas durante 50 días tienen mayores tasas de germinación (64.2 %) que las de 20 (44.8 %) y 0 días (16. 5 %).""White oaks have recalcitrant seeds that remain viable for short periods of time, but this information is still conspicuously lacking for Mexican oaks. This is the case of Quercus polymorpha, a drought-tolerant species widely distributed across Sierra Madre Oriental that can be used in forest restoration programs. The acorns used to develop their saplings are collected during the reproductive season and stored by several months before their germination. This study focused in 1) determining how many seeds are lost during storage because of physiological factors linked to their viability, 2) quantifying how many seeds were lost by other factors, and 3) assessing whether cold stratification can stimulate acorn germination. Acorns used in this study were stored during a round year. We found that 70 % of these acorns were parasitized by insects prior to their storage, while an additional 20 % had lost their viability due to physiological factors or fungal infestation. Germination trials were performed by only using potentially viable acorns, which were subjected to three different cold stratification periods (0, 20 and 50 days). This experiment indicated acorns stratified during 50 days display higher germination rates (64.2 %) than those stratified by 20 (44.8 %) and 0 days (16.5 %).
Ecophysiological and anatomical mechanisms behind the nurse effect: which are more important? A multivariate approach for cactus seedlings
Get PDF"Background: Cacti establish mostly occurs under the canopy of nurse plants which provide a less stressful micro-environment, although mechanisms underlying this process are unknown. The impact of the combination of light and watering treatments on Opuntia streptacantha (Cactaceae) seedlings was examined.
Methods/Principal Findings: Ecophysiological [titratable acidity, osmotic potential ('solute potential', psi(s)), relative growth rate (RGR) and their components (NAR, SLA, and LWR)], anatomical (chloroplast density, chloroplast frequency, and cell area), and environmental [photosynthetic photon flux density (PPFD) and air temperature] sets of variables were analyzed, assessing relationships between them and measuring the intensity of the relationships. Three harvests were carried out at days 15, 30, and 45. psi(s) and acidity content were the most important responses for seedling establishment. The main anatomical and environmental variables were chloroplast density and water availability, respectively. Opuntia streptacantha seedlings establish better in the shade-watering treatment, due to higher psi(s) and acidity, unaffected chloroplasts, and lower PPFD. In addition, the chloroplasts of cells under high-light and non-watering treatment were clumped closer to the center of the cytosol than those under shade-drought, to avoid photoinhibition and/or to better distribute or utilize the penetrating light in the green plant tissue.
Conclusions: Opuntia seedlings grow better under the shade, although they can tolerate drought in open spaces by increasing and moving chloroplasts and avoiding drastic decreases in their psi(s). This tolerance could have important implications for predicting the impact of climate change on natural desert regeneration, as well as for planning reforestation-afforestation practices, and rural land uses.
La acetiltransferasa de histonas TGF-1 es el coactivador de genes inducibles por la luz azul en Trichoderma atroviride
No full textTesis (Doctorado en Ciencias en Biología Molecular)"En el hongo filamentoso Neurospora crassa, las proteínas White Collar 1 y 2 (WC-1 y WC-2) regulan todas las respuestas a luz azul descritas hasta hora. La proteína WC-1 es el fotorreceptor y junto con la proteína WC-2 con la que forma un complejo regulador, fungen como factores transcripcionales de los genes inducibles por luz azul. La acetil transferasa de histonas NGF-1 es el coactivador de genes de respuesta a luz azul e interacciona físicamente con WC-1 para regular la fotorespuesta. En Trichoderma, las proteínas ortólogas a WC-1 y WC-2 son BLR-1 y BLR-2 respectivamente, que también regulan respuestas a la luz, formando un complejo en el que, presumiblemente, BLR-1 actúa como el fotorreceptor. En el presente trabajo se demostró que la luz azul induce la acetilación global de la histona H3. La mutante del gen tgf-1, el cual codifica probablemente para una acetil transferasa de histonas, presenta un fenotipo pleiotrópico, afectando especialmente el crecimiento y desarrollo de T. atroviride. Diversos análisis transcripcionales y de inmunoprecipitación de la cromatina (ChIP) demostraron que la proteína TGF-1 es un coactivador de genes que responden a luz azul, probablemente a través de la acetilación de los residuos de lisina K9 y K14 de la histona H3 que forma parte de la cromatina asociada a los promotores de dichos genes. Demostramos también que se requiere de TGF-1 en la oscuridad para mantener los niveles basales del gen bld-2 (blue light down regulated 2) que está regulado negativamente por luz azul. Además se requiere, después de un pulso de luz azul, de la presencia de TGF-1 para llevar a cabo la acetilación transitoria de la histona H3 del promotor del gen phr-1.""In the filamentous fungus Neurospora crassa, the White Collar -1 and 2 proteins (WC-1 and WC-2) regulate all known responses to blue light. The WC-1 protein is the photoreceptor and together with WC-2 function as transcription factors of blue light inducible genes. The histone acetyltransferase NGF-1, the orthologue of Gcn5 from Saccharomyces cerevisiae, is the co-activator of blue light induced genes in N. crassa and physically interacts with WC-1 to regulate blue light response. In Trichoderma, the WC-1 and WC-2 orthologues, BLR-1 and BLR-2, regulate as well blue light responses. BLR-1 has been proposed as the blue light receptor. Here we show that blue light induced a global acetylation of histone H3. Deletion of tgf-1, which encodes a putative acetyl transference, the orthologue of NGF-1, led to a pleiotropic phenotype, mainly affecting growth and development. Transcription and Chromatin immunoprecipitation (ChIP) analyses showed that TGF-1 is the co-activator of blue light regulated genes, probably by acetylating the K9 and K14 lysine residues of histone H3 on the promoters in T. atroviride. Furthermore, we demonstrate that TGF-1 is necessary to maintain the basal level of expression of bld-2 in the dark. TGF-1 was necessary for histone H3 acetylation of the promoter of phr-1 (blue light upregulated) after a blue light pulse, since the Δtgf-1 mutant showed no histone H3 acetylation on the phr-1 promoter.
Las Subunidades del receptor P2X4 forman parte de los canales P2X nativos en las neuronas mientéricas del ráton.
Get PDFTesis (Doctorado en Ciencias en Biologia Molecular)"El objetivo del presente estudio fue investigar si los receptores P2X4 se expresan en las neuronas mientéricas del ratón y si estos contribuyen a la formación de canales funcionales en la membrana de estas neuronas mediante técnicas moleculares y electrofisiológicas. La técnica electrofisiológica de whole-cell se utilizó para registrar las corrientes inducidas al aplicar ATP (IATP) en las neuronas mientéricas. Comparados con los canales P2X4 recombinantes (reportados por otros autores en estudios previos), los canales P2X mientéricos nativos tienen una sensibilidad al ATP (EC50=102 μM) y al α,β-metileno ATP (ningún efecto a 30 o 100 μM) relativamente baja. El BzATP fue un agonista débil de los receptores P2X nativos. KN-62 no tuvo efecto sobre éstos canales, mientras que el PPADS (IC50=0.54 μM) y la suramina (IC50=134 μM) fueron antagonistas más potentes que sobre los canales P2X4 homoméricos. Las IATP fueron potenciadas por la ivermectina (efecto que es específico sobre los receptores P2X4) y el zinc. Análisis por Western blot y RT-PCR mostró la presencia de la proteína de la subunidad P2X4 y el correspondiente transcrito de mRNA en el intestino delgado. Se encontró inmunoreactividad para el receptor P2X4 en la mayoría de las neuronas mientéricas en cultivo. La técnica de RT-PCR en célula única mostró la presencia de mRNA del receptor en el 90% de las neuronas mientéricas. Nuestros resultados muestran que el receptor P2X4 se expresa en la mayoría de las neuronas mientéricas, contribuye a las corrientes de membrana inducidas por ATP, y debido a que la mayoría de las propiedades observadas en dichas neuronas no corresponden a las de los canales P2X4 homoméricos, se propone que están formando canales heteroméricos. Los receptores P2X4 tienen una amplia distribución dentro del plexo mientérico y se esperaría que jueguen un papel importante en la vía de señalización intracelular.""The aim of the present study was to investigate if P2X4 receptors are expressed in murine myenteric neurons and if these receptors contribute to form functional channels in the neuronal membrane by using molecular and electrophysiological techniques. The whole-cell recording technique was used to record membrane currents induced by ATP (IATP) in myenteric neurons. Compared with recombinant P2X4 receptor channels (reported by others in a previous study), native myenteric P2X receptors have a relative lower sensitivity for ATP (EC50=102 μM) and α,β- methylene ATP (not effect at 30 or 100 μM). BzATP was a weak agonist for native P2X receptors. KN-62 had no effect on myenteric P2X channels whereas PPADS (IC50=0.54 μM) and suramin (IC50=134 μM) were more potent antagonists than on P2X4 homomeric channels. IATP were potentiated by ivermectin (effect that is specific on P2X4 receptors) and zinc. Western blotting shows the presence of P2X4 protein and RT-PCR the corresponding mRNA transcript in the small intestine. Immunoreactivity for P2X4 receptors was found in most myenteric neurons in culture. Single-cell RT-PCR shows the presence of P2X4 mRNA in 90% of myenteric neurons. Our results indicate that P2X4 receptors are expressed in the majority of myenteric neurons, contribute to the membrane currents activated by ATP, and because most properties do not correspond to P2X4 homomeric channels it is proposed that they are forming heteromeric channels. P2X4 subunits have a widespread distribution within the myenteric plexus and would be expected to play an important role in cell signaling.
Geología y magnetometría aérea del Graben de Villa de Reyes, San Luis Potosí, Mesa Central de México: implicaciones tectónicas y geohidrológicas
Get PDF"El estudio realizado está enfocado a conocer la geología y tectónica del subsuelo en el Graben de Villa de Reyes. Para ello se procesan datos aeromagnéticos por medio de una serie de filtros matemáticos que permiten resaltar información en unos casos u obscurecerla en otros, con el fin de observar y analizar estructuras geológicas superficiales o profundas. El estudio permitió identificar zonas de falla y/o fracturas bajo la cubierta aluvial, así como identificar zonas de fuente bajo los depósitos volcánicos en los hombros del Graben de Villa de Reyes. Los lineamientos aeromagnéticos interpretados permitieron identificar las zonas de recarga del acuífero de la zona.""The study is focused on learning about the underground geology and tectonics in the Villa de Reyes Graben. The aeromagnetic data is processed through a series of mathematical filters that allow us to increase the resolution of weak anomalies in some cases or, in others, to simplify the appearence of magnetic maps by suppressing local features in order to observe and analyze surface or deep geological structures. The study allowed us to identify fault and/or fractures zones that are under alluvial cover, and to identify sources of volcanic activity beneath the existing volcanic deposits on the shoulders of the Villa de Reyes Graben. The interpreted aeromagnetic trends allowed us to identify the aquifer recharge zone in the area.
Nonlinear filtering preserves chaotic synchronization via master-slave system
Get PDF"We present a study on a class of interconnected nonlinear systems and give some criteria for them to behave like a filter. Some chaotic systems present this kind of interconnected nonlinear structure, which enables the synchronization of a master-slave system. Interconnected nonlinear filters have been defined in terms of interconnected nonlinear systems. Furthermore, their behaviors have been studied numerically and theoretically on different input signals.
Implementación de un algoritmo con el método de diferencias finitas en el dominio del tiempo para estudiar propiedades ópticas en metales
Get PDFTesis (Maestría en Ciencia de Materiales)"Todos los fenómenos relacionados con los campos electromagnéticos son correctamente descritos por la teoría electromagnética desarrollada por James Clerk Maxwell en 1873, donde se conecta y se formula matemáticamente las leyes conocidas de Gauss, Faraday y Ampere, confirmando con esta teoría, la naturaleza ondulatoria de la luz, propagandose tanto en el vacío como en los materiales. La teoría de Drude es un modelo para estudiar las propiedades fisicas de los metales, y principalmente proporciona una función dieléctrica que nos ayuda a estudiar la interacción entre los metales y la luz.Una herramienta que nos permite resolver las ecuaciones de Maxwell dependientes del tiempo de forma numérica, describiendo correctamente el fenómeno de la interacción luz-materia, es el metodo de Diferencias Finitas en el dominio del tiempo (FDTD, por sus siglas en Ingles). Este método ha sido ampliamente utilizado en el campos de investigación en ingeniería, tales como el eléctrico, el militar, en sistemas de telecomunicaciones, etc.; y mas recientemente en el estudio de nanoestructuras metálicas. Se complementará el método FDTD con la implementación de condiciones de frontera absorbentes, como son las capas perfectamente adaptadas (PML, por sus siglas en Ingles). Se presentan los resultados del algoritmo desarrollado para partículas individuales de metal en una (1D) y dos (2D) dimensiones.""All phenomena related to electromagnetic fields are correctly described by the electromagnetic theory developed by James Clerk Maxwell in 1873, where he connected and mathematically formulated the laws known from Gauss, Faraday and Ampere, confirming with this theory the wave nature of light, which propagates in vacuum as well as in materials. The Drude theory is a model to study physical properties in metals, which mainly provides a dielectric function which helps us to study the interaction between metals and light. A tool that allows us to solve the time dependent Maxwell equations in a numeric way, describing correctly the phenomenon of light-matter interaction, is the FiniteDifferences Time Domain method (FDTD). This method has been widely used in field of engineering research, such as electric, military, telecommunications systems and recently in the study of metal nanostructures. You will complement the FDTD method with the implementation of absorbing boundary conditions, such as are the layers perfectly matched (PML). We present results of the developed algorithm for individual metal particles in one and two dimensions.