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Oligonucleotides of Candida tropicallis, detection method and kit comprising same
No full text"The invention discloses an in vitro method for the identification of Candida tropicalis, the sequences associated to said identification, as well as diagnosis kits for identifying Candida tropicalis.""La invención describe un método in vitro de identificación de Candida tropicalis, las secuencias asociadas a dicha identificación, así como kits de diagnóstico para identificar Candida tropicalis.
Expression, purification and preliminary crystallization of amaranth 11S proglobulin seed storage protein from Amaranthus hypochondriacus L.
Get PDF"11S globulin is one of the major seed storage proteins in amaranth. Recombinant protein was produced as up to similar to 80% of the total bacterial protein using Escherichia coli Rosetta-gami (DE3) containing pET21d with amaranth 11S globulin cDNA. The best expression condition was at 302 K for 20 h using LB medium containing 0.5 M NaCl. The recombinant protein was easily separated from most of the Escherichia coli proteins by precipitation with 0-40% ammonium sulfate solution. It formed aggregates at low temperature and at low salt concentrations. This behaviour may imply that it has a more hydrophobic nature than other 11S seed globulins. The crystals diffracted to 6 A resolution and belonged to space group P6(3), with unit-cell parameters a = b = 97.6, c = 74.8 A, gamma = 120.0 degrees. One subunit of a trimer was estimated to be present in the asymmetric unit, assuming a V (sol) of 41%. To obtain the complete structure solution, experiments to improve crystallization and flash-cooling conditions are in progress.
Effect of light on seed germination of succulent species from the southern Chihuahuan Desert: comparing germinability and relative light germination
Get PDF"Light requirements for cactus seed germination have been considered to be associated with their life form, but this has not been thoroughly studied for other succulent species. In this study, we performed a light and darkness experiment in 11 species: seven rosette species (Agavaceae) and two columnar, one barriliform, and one globose species (Cactaceae) from the Southern Chihuahuan Desert. The response variables were seed germination percentage or germinability and relative light germination (RLG). Following germinability analyses, only the barriliform cacti E. platyacanthus was positive photoblastic. All other species were neutral photoblastic, although we found three response patterns: species having similar seed germination in light and darkness conditions, species showing higher seed germination in darkness than in light, and species showing higher germination in light than in darkness. However, following the relative light germination (RLG) analyses, two columnar species had higher RLG than the other species, seven species showed intermediate RLG (RLG 0.49-0.67), and two species had low RLG, which indicates that they germinated best in darkness. Our results do not support the suggestion that columnar cacti are neutral photoblastic and that globose cacti are positive photoblastic. We suggest that RLG is a better expression of the species' light requirement than seed germination percentage.
Magnetism of small Cr clusters: interplay between structure, magnetic order, and electron correlations
Get PDF"The magnetic properties of small Cr-N clusters (N <= 6) are investigated in the framework of density-functional theory. The interplay between electron correlations, cluster structure, and magnetic order is quantified by performing fully spin-unrestricted calculations allowing for noncollinear spin arrangements within both the local-spin-density approximation (LSDA) and the generalized-gradient approximation (GGA). The possible transition or saddle-point states are identified by determining the vibrational frequencies from diagonalizing the dynamical matrix. In agreement with previous studies, a dimer-based growth pattern is found in all considered low-lying isomers with very short equilibrium bond lengths (typically d(eq)(GGA)=1.55-1.65 angstrom) alternating with relative long ones (typically d(eq)(GGA)=2.75-2.85 angstrom) in the relaxed geometries. Strong local magnetic moments (mu) over right arrow (i) are, in general, obtained for the relaxed geometries (e.g., vertical bar mu(GGA)(i)vertical bar similar or equal to 2 mu(B) in Cr-4), which show a collinear magnetic order with antiparallel (parallel) alignment of the (mu) over right arrow (i) along the short (long) bonds. In contrast to the GGA, the LSDA yields vanishing magnetization density in some cases (vertical bar mu(LSDA)(i)vertical bar=0 for all i for N=2 and 4). Despite quantitative differences, both LSDA and GGA functionals always yield collinear ground-state solutions for the fully relaxed structures. In fact, noncollinear spin arrangements are found only for particular symmetric (nondimerized) geometries. However, the structures are not local minima and involve considerably large excitation energies. The results clearly indicate that the magnetic frustration, which one would physically expect in compact antiferromagnetic spin systems, is solved by dimerization rather than by noncollinearity of the local moments.
Detection of mixed-culture growth in the total biomass data by wavelet transforms
Get PDF"We have shown elsewhere that the presence of mixed-culture growth of microbial species in fermentation processes can be detected with high accuracy by employing the wavelet transform. This is achieved because the crosses in the different growth processes contributing to the total biomass signal appear as singularities that are very well evidenced through their singularity cones in the wavelet transform. However, we used very simple two-species cases. In this work, we extend the wavelet method to a more complicated illustrative fermentation case of three microbial species for which we employ several wavelets of different number of vanishing moments in order to eliminate possible numerical artifacts. Working in this way allows to filter in a more precise way the numerical values of the Hölder exponents. Therefore, we were able to determine the characteristic Hölder exponents for the corresponding crossing singularities of the microbial growth processes and their stability logarithmic scale ranges up to the first decimal in the value of the characteristic exponents. Since calibrating the mixed microbial growth by means of their Hölder exponents could have potential industrial applications, the dependence of the Hölder exponents on the kinetic and physical parameters of the growth models remains as a future experimental task.
Estudio de la regulación de la CTA1 (catalasa I) de Candida glabrata en la respuesta a estrés oxidativo.
Get PDFTesis (Maestría en Ciencias en Biología Molecular)"Candida glabrata es una levadura haploide no dimórfica más cercana filogenéticamente a Saccharomyces cerevisiae, levadura no patógena, que con Candida albicans. Parte del éxito de C. glabrata para sobrevivir en el hospedero, puede deberse a la habilidad para evadir eficientemente las Especies Reactivas de Oxígeno (ERO) producidas por las células fagocíticas. La única catalasa que posee C. glabrata (CTA1) le permite resistir a altas concentraciones de H2O2 (1000 mM) in vitro. CgCTA1 se induce dentro de los macrófagos. S. cerevisiae posee dos isoenzimas de catalasa, una peroxisomal (Cta1p) y otra citosólica (Ctt1p) que son reguladas diferencialmente, sin embargo, S. cerevisiae no es tan resistente a H2O2 como Candida glabrata y Candida albicans. Estos datos sugieren que responder al estrés oxidativo juega un papel importante para la sobrevivencia de este patógeno en el hospedero. Para determinar como se regula la catalasa de C. glabrata usamos dos fusiones con GFP como gen reportero una traduccional PCgCTA1CTA1:GFP y otra transcripcional PCTA1:GFP. La regulación transcripcional de la catalasa está mediada principalmente por los factores de transcripción Yap1p y Skn7p en fase exponencial durante estrés oxidativo, mientras que los factores Msn2p y Msn4p son importantes en fase estacionaria. Para caracterizar la importación de la Cta1p al peroxisoma realizamos mutaciones puntuales en los motivos internos de importación al peroxisoma SKF149. La mutación SKF149 y SKF373 son importantes para la función de la CgCta1p. Con el fin de comprobar si la CgCta1p le confiere a S. cerevisiae una resistencia mayor a H2O2 complementamos las mutantes de S. cerevisiae cta1Δ, ctt1Δ y cta1Δctt1Δ con PScCTA1CTA1::GFP.""Candida glabrata is a haploid yeast closely related phylogenetically to Saccharomyces cerevisiae, a non-pathogenic yeast and distantly related to Candida albicans. C.glabrata has ability to survive inside the host may be due to its ability to efficiently evade killing by Reactive Oxygen Species (ROS) produced by phagocytic cells. C. glabrata has a single catalase (CTA1) and mediates resistance to high concentrations of H2O2 (1000 mM) in vitro. CgCTA1 is induced inside macrophages. S. cerevisiae has two catalase genes which are regulated differentially. Cta1p is a peroxisomal catalase and Ctt1p is a cytosolic catalase, however, S. cerevisiae is not as resistant to H2O2 (100 mM) as Candida species. These results suggest that the oxidative stress response may be playing an important role in the survival of this pathogen in the host. To determine the regulation of CTA1, we used a translational (PCgCTA1CTA1::GFP) and transcriptional (PCTA1::GFP) fusions with GFP as reporter gene. The transcriptional regulation of catalase is mediated mainly by Yap1p and Skn7p in exponential phase during oxidative stress whereas Msn2p and Msn4p are important in stationary phase. To characterize how CgCTA1 is imported to the peroxisomes, we made point mutations in the putative peroxisome import motives SKF149 and SKF373. The mutations SKF149 and SKF373 are important for CgCta1p function. To determine whether the CgCta1p confers enhanced resistance in S.cerevisiae to H2O2, we complemented S. cerevisiae mutant strains in cta1Δ, ctt1Δ and cta1Δctt1Δ with PScCTA1CTA1::GFP.
A simple circuit with dynamic logic architecture of basic logic gates
Get PDF"We report experimental results obtained with a circuit possessing dynamic logic architecture based on one of the theoretical schemes proposed by H. Peng and collaborators in 2008. The schematic diagram of the electronic circuit and its implementation to get different basic logic gates are displayed and discussed. In particular, we show explicitly how to get the electronic NOR, NAND and XOR gates. The proposed electronic circuit is easy to build because it employs only resistors, operational amplifiers and comparators.
Seed germination of Opuntia species from an aridity gradient in Central Mexico
Get PDF"In the Mexican highlands there are several aridity gradients affecting Opuntia species composition and its biological function. Since environmental variations can affect plant traits like seed morphology as well as related processes, we conducted experiments in order to determine whether seed mass, testa hardness, seed imbibition, dormancy type, polyembryony occurrence, and different habitats are related with interspecific variation of seed germination in Opuntia spp. Our results showed that there were interspecific differences of seed attributes among seven Opuntia species along an environmental gradient in Central Mexico. Seeds of most species were able to imbibe water; however, mechanical scarification treatment did not break seed dormancy, but promoted faster germination. This pattern might be a result of the testa porosity. Seed hardness was negatively correlated with seed germination in Opuntia jaliscana; thus harder seeds had lower germination percentage. In contrast, seeds of O. robusta increased their germination percentage as seed hardness increased. We found differences in seed mass among species and localities; seeds collected in moist areas were heavier. There was evidenced a correlation of seed mass with seed germination for O. jaliscana. Polyembryony was present in four of the seven species studied and it appears to be more frequent in seeds from dry sites of the gradient.
Stability conditions for integral delay systems
Get PDF"In this paper we consider a special class of integral delay systems arising in several stability problems of time‐delay systems. For these integral systems we derive stability and robust stability conditions in terms of Lyapunov–Krasovskii functionals. More explicitly, after providing the stability conditions we compute quadratic functionals and apply them to derive exponential estimates for solutions, and robust stability conditions for perturbed integral delay systems.
La exploración magnética aérea en la prospección de yacimientos de oro y plata: caso Peña de Bernal, Querétaro
Get PDFTesis (Maestría en Ciencias Ambientales)"En el presente trabajo se realizaron el procesamiento e interpretación de datos de un vuelo aeromagnético de alta resolución, realizado por la compañía McPhar Geosurveyes Ltd., sobre las inmediaciones de Peña de Bernal, Querétaro, para la prospección de nuevas fuentes minerales y la extensión de las ya conocidas, pertenecientes a la Compañía minera San Martín, asociadas a cuerpos intrusivos que se relacionen con anomalías magnéticas. El procesamiento de la información aeromagnética consistió en la aplicación de algoritmos matemáticos (filtros) como, reducción al polo, derivadas en la vertical, continuaciones de las medidas del campo magnético a diferentes alturas, señal analítica, Butterworth y susceptibilidad aparente, los cuales permiten eliminar altas frecuencias asociadas a ruido y destacar bajas frecuencias asociadas con información de fondo. La continuación hacia arriba a 250 m, mediante la técnica de dominios aeromagnéticos, en función del carácter de la intensidad del campo magnético, permitió definir ocho dominios, siendo de mayor importancia los dominios I y II con intensidades de (50-200 nT y -200-0 nT). La reducción al polo permitió trazar lineamientos (contactos, fallas) en el área de estudio, con una orientación NE-SW y NW-SE. Con la sobre posición de los mapas, reducción al polo, señal analítica, derivadas en la vertical y Butterworth; se confirmaron las zonas actualmente en explotación (San Martín y Chicarroma), las cuales presentan las mejores posibilidades para su aprovechamiento, así mismo se identificaron diez prospectos con potencial minero de interés. La señal analítica continuada 1000 m hacia arriba, permitió interpretar la existencia de un cuerpo intrusivo ubicado al norte del poblado de San Martín y al este de Peña de Bernal, a una profundidad de 1.5 km, envolviendo un área de 23 km2, asociado con una anomalía monopolar. La modelación 2D de las anomalías magnéticas permitió la interpretación de las características geológicas del subsuelo (roca encajonante e intrusivo,) y la relación con las estructuras mineralizadas emplazadas en fallas a partir del trazado de perfiles.""This work was carried out processing and interpreting a high resolution aeromagnetic flight, executed by the McPhar GeoSurvey Ltd. company on the vecinity of Peña de Bernal, Queretaro. The objective of this work was consisted of to prospect new mineralized areas and to extend the already known areas of the San Martin mining company, associated to the intrusive bodies related to the magnetic anomalies present in the area. The aeromagnetic data processing consisted in the application of mathematical algorithms (filters), such as reduction to the pole, vertical derivatives, continuation of the magnetic field measurements at different heights, analytical signal, Butterworth, and apparent susceptibility, which can eliminate high frequencies associated to noise and to detail the low frequencies associated with the background information. The upward continuation to 250 m, using the aeromagnetic domain technique as a function of the nature of the magnetic field intensity, has defined eight domains, the most important being the domains I and II with intensities (50-200 nT and - 200-0 nT) respectively. Reduction to the pole method allowed to draw lines (contacts and faults) in the study area, with NE-SW and NW-SE orientations. The superposition, reduction to the pole, analytic signal, vertical derivative and Butterworth, methods were confirmed on the current operating areas (San Martin and Chicarroma), which presented the best possibilities to be used; in addition, ten mining prospects were identified with good ore potential. The continuous analytical signal 1000 m upwards allowed us to interpret the presence of an intrusive body located north of the San Martin town and east of Peña de Bernal, at a depth of 1.5 km, enclosing an area of 23 km2, and associated with a monopolar anomaly. The 2D magnetic anomaly model allowed the interpretation of subsurface geological features (the intrusive host rock), and the relationship with the mineralized structures located along the faults detected by the profiles.