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Search Results: 1 - 10 of 367610 matches for " Elena de la Casa-Esperón "
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Horizontal Transfer and the Evolution of Host-Pathogen Interactions
Elena de la Casa-Esperón
International Journal of Evolutionary Biology , 2012, DOI: 10.1155/2012/679045
Abstract: Horizontal gene transfer has been long known in viruses and prokaryotes, but its importance in eukaryotes has been only acknowledged recently. Close contact between organisms, as it occurs between pathogens and their hosts, facilitates the occurrence of DNA transfer events. Once inserted in a foreign genome, DNA sequences have sometimes been coopted by pathogens to improve their survival or infectivity, or by hosts to protect themselves against the harm of pathogens. Hence, horizontal transfer constitutes a source of novel sequences that can be adopted to change the host-pathogen interactions. Therefore, horizontal transfer can have an important impact on the coevolution of pathogens and their hosts. 1. Introduction The evolution of pathogens and their hosts is often interpreted as an arms race: while hosts have developed multiple mechanisms to protect themselves, pathogens have generated diverse strategies to evade their hosts’ defenses. But pathogens and hosts have also evolved mechanisms that allow a mutualistic coexistence. During their coevolution, a relationship between pathogen and host has been established based on intricate and specialized molecular interactions. One of the possible outcomes of this long-standing and close relationship is the exchange of genetic material. Horizontal or lateral gene transfer (HT) is the nonsexual movement of genetic information between two organisms [1]. These sequences can be modified and adapted (i.e., coopted, domesticated) during the evolution of the recipient species to improve their own survival. When HT occurs between hosts and their pathogens (in one direction or the other), the acquired sequences can be coopted to affect how the two organisms interact with each other. Pathogens have developed an impressive array of strategies to avoid host defenses, including the interference or disruption of the host defensive mechanisms and signaling cascades. For instance, vertebrate viruses can avoid detection and elimination by the host immune response by obstructing antigen presentation, blocking apoptosis, disrupting complement cascades, and mimicking or modulating cytokines and their receptors, among others [2, 3]. I will discuss how several of these strategies have been achieved through the acquisition and domestication of host genes. Hosts, in turn, can protect themselves from the deleterious effects of infections by two approaches: resistance and tolerance [4, 5]. Resistant traits reduce damage by limiting the pathogen growth and, therefore, the extent of the infection, sometimes eliminating the pathogen
Antimicrobial Resistance Genes in Animal Manure, Manure-Amended and Nonanthropogenically Impacted Soils in Spain  [PDF]
Fernando Esperón, Carlos Sacristán, Matilde Carballo, Ana de la Torre
Advances in Bioscience and Biotechnology (ABB) , 2018, DOI: 10.4236/abb.2018.99032
Abstract: Environmental dissemination of antimicrobial resistance genes may occur through agricultural residues, such as animal manure. We studied the resistome of 16 pool samples of animal manure (pig slurry [n = 8] and poultry manure [n = 8]), and 16 soil samples (manure-amended [n = 8] and nonmanure-amended [n = 8]). All samples were collected in central Spain. Detection was based on 18 selected antimicrobial resistance genes (ARGs). The most commonly detected genes in animal manure were sul1 (16/16), sul2 (16/16), tet(A) (16/16), aadA (16/16), tet(B) (15/16), and str (15/16). Genes blaTEM (7/8), mecA (6/8), vanA (5/8) and qnrB (4/8) were more frequently detected in chicken manure, whereas pig slurry samples presented higher levels of tet(C) (8/8) and tet(M) (8/8). Out of the four genes selected for their clinical relevance, three—blaCTX-M
Occurrence of tetracycline residues and antimicrobial resistance in gram negative bacteria isolates from cattle farms in Spain  [PDF]
Matilde Carballo, Fernando Esperón, Carlos Sacristán, Miguel González, Belén Vázquez, Sonia Aguayo, Ana de la Torre
Advances in Bioscience and Biotechnology (ABB) , 2013, DOI: 10.4236/abb.2013.42A040
Abstract:
The usage of antibiotics in animal husbandry has dramatically increased the concentration of antibiotic residues and has promoted the development and abundance of antibiotic resistance in manure. When it is spread onto agricultural land, both residues of antibiotics and bacteria carrying antibiotic resistance genes may be introduced into the environment. In this research, we isolated resistant gram negative bacteria from manure produced in two dairy and two beef cattle farms, located in Madrid (Spain), to determine their resistance to seventeen representative antibiotics commonly used in veterinary therapy. A total of 63 isolates were used to assess the overall bacterial antimicrobial resistance on cattle manure samples. Predominant species were Escherichia coli and Comamonas testosteroni accounting for 25% and 19.6% of the total, respectively. The most found antimicrobial resistances in gram-negative bacteria were to tetracycline (66.7%), sulphamethoxazole (55.6%), ampicillin (52.4%), cephalothin (46.0%), chloramphenicol (44.4%), nalidixic acid (39.7%) and trimethroprim- sulphamethoxazole (33.3%). The mean of resistance and the percentage of multi-resistant bacteria in beef farms were higher and statistically significant when compared to dairy farms which is opposite from the findings of the previous studies. The presence of three tetracyclines in all manure samples was also examined with stable recoveries (76% - 82%) and high sensitivity (limit of quantification 0.015 - 0.03 μg/kg). The concentrations of tetracyclines detected (<0.015 - 10 mg/kg) were consistent to the theoretical tetracycline levels in manure in Spain according to the ex- cretion rate of these antibiotics and the values re-ported in scientific literature in other European coun- tries.
Contenido orgánico de extractos parcialmente purificados de pulpa dental humana y bovina
Salas,María Mercedes; de la Casa,María Luisa; López,María Elena;
Acta bioqu?-mica cl?-nica latinoamericana , 2011,
Abstract: the dental pulp contains connective tissue and is rich in proteins, mainly collagen. the aim of this study was to describe a purification method for organic compounds of human and bovine pulp tissues, either vital as necrotic, in order to validate the experimental bovine model. extracts of 50 mg of the middle fraction of one root pulp teeth, 20 humans or 1 bovine, in 500 μl of cold 50 mm tris - hcl ph 7.4, 1 mm phenyl methyl sulfonyl fluoride and 5 mm benzamidine hydrochloride were prepared. extracts were homogenized and centrifuged at 10000 rpm. supernatants were partially purified with 1% protamine sulphate, sediments re-suspended and dialyzed during 2 hours with a spare in 500 mm sodium acetate ph 6. proteins, hydroxiproline and carbohydrates were determined, and the yield of the process was calculated according to the hydroxiproline content. poliacrylamide gel electrophoresis was applied. a greater organic content was found in human than in bovine tissue, and in vital rather than in the necrotic one. hydroxyproline/ proteins and yield evidenced that bovine extract would contain a larger proportion of collagen. bands at 78 and 80 kda in human pulp and at 74 and 76 kda in the bovine tissue were observed. there was no difference between vital and necrotic tissues. the qualitative and quantitative evidences expressed in this work would validate the bovine research endodontic model.
Onset of the Rainy Season in the Province of Córdoba (Argentina) Determined by Rainfall Records and Evaluation of its Agricultural Risk Condition
de la Casa,Antonio;
Chilean journal of agricultural research , 2009, DOI: 10.4067/S0718-58392009000400012
Abstract: knowing more precisely the onset of the rainy season in a region would reduce risk at crop establishment. to evaluate this issue, the study proposes a simple procedure based only on daily rainfall data to estimate the onset of the wet season, by analyzing records of seven meteorological stations in the province of córdoba between the years 1961 and 2006. the onset of the rainy season was defined according to the simultaneous occurrence of two conditions: (i) the amount of rainfall in 3 consecutive days equal to or greater than 20 or 30 mm, (ii) a period without rain of 7 to 16 d during the subsequent 30-d period. onset of the rainy season shows strong interannual variability throughout the region. an increase from 20 to 30 mm of rain in 3 successive days delays the onset date, which on the average reaches a maximum of 8 to 13 d, according to location. by allowing a longer period without rain after the initial event, the onset date is systematically earlier by16 to 35 d, depending on initial conditions. furthermore, the relationship between the onset date and cumulative rainfall in the subsequent 30 d was evaluated with the bivariate normal distribution to estimate the risk level that influences the early sowing decision.
Onset of the Rainy Season in the Province of Córdoba (Argentina) Determined by Rainfall Records and Evaluation of its Agricultural Risk Condition Determinación del Comienzo de la Estación de Lluvias en la Provincia de Córdoba (Argentina) a partir de Registros Pluviométricos y Evaluación de su Condición de Riesgo Agrícola
Antonio de la Casa
Chilean Journal of Agricultural Research , 2009,
Abstract: Knowing more precisely the onset of the rainy season in a region would reduce risk at crop establishment. To evaluate this issue, the study proposes a simple procedure based only on daily rainfall data to estimate the onset of the wet season, by analyzing records of seven meteorological stations in the Province of Córdoba between the years 1961 and 2006. The onset of the rainy season was defined according to the simultaneous occurrence of two conditions: (i) the amount of rainfall in 3 consecutive days equal to or greater than 20 or 30 mm, (ii) a period without rain of 7 to 16 d during the subsequent 30-d period. Onset of the rainy season shows strong interannual variability throughout the region. An increase from 20 to 30 mm of rain in 3 successive days delays the onset date, which on the average reaches a maximum of 8 to 13 d, according to location. By allowing a longer period without rain after the initial event, the onset date is systematically earlier by16 to 35 d, depending on initial conditions. Furthermore, the relationship between the onset date and cumulative rainfall in the subsequent 30 d was evaluated with the bivariate normal distribution to estimate the risk level that influences the early sowing decision. Conocer con mayor precisión el comienzo de la estación de lluvias en una región reduciría el riesgo de implantación inicial de los cultivos. Esta problemática se evaluó con un procedimiento que utiliza sólo datos de lluvia diarios para estimar el comienzo de la estación húmeda, analizando registros de siete localidades de la Provincia de Córdoba entre 1961 y 2006. El comienzo de la estación de lluvias se definió de acuerdo a la ocurrencia concurrente de dos condiciones: (i) un valor de precipitación en 3 días sucesivos igual o mayor a 20 mm o 30 mm; y (ii) un lapso sin lluvia que se extiende de 7 a 16 días durante el período de 30 días posterior. El comienzo de la estación de lluvias acusa una fuerte variabilidad interanual en toda la región. Al aumentar de 20 a 30 mm el monto de la lluvia en tres días sucesivos, se produce un retraso en la fecha de inicio que en término medio alcanza como máximo entre 8 y 13 días, de acuerdo a la localidad considerada. Al admitir un lapso sin lluvias posterior al inicio más extenso, se produce un adelanto sistemático de la fecha de inicio, de entre 16 y 35 días de acuerdo a las condiciones iniciales. Además, se estableció la relación entre la fecha de inicio y la lluvia acumulada en los 30 días posteriores, que se evaluó a partir de la distribución normal bivariada para estimar el nivel de riesgo que s
Intronic Parent-of-Origin Dependent Differential Methylation at the Actn1 Gene Is Conserved in Rodents but Is Not Associated with Imprinted Expression
John D. Calaway, José Ignacio Domínguez, Megan E. Hanson, Ezequiel C. Cambranis, Fernando Pardo-Manuel de Villena, Elena de la Casa-Esperon
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0048936
Abstract: Parent-of-origin differential DNA methylation has been associated with regulation of the preferential expression of paternal or maternal alleles of imprinted genes. Based on this association, recent studies have searched for parent-of-origin dependent differentially methylated regions in order to identify new imprinted genes in their vicinity. In a previous genome-wide analysis of mouse brain DNA methylation, we found a novel differentially methylated region in a CpG island located in the last intron of the alpha 1 Actinin (Actn1) gene. In this region, preferential methylation of the maternal allele was observed; however, there were no reports of imprinted expression of Actn1. Therefore, we have tested if differential methylation of this region is common to other tissues and species and affects the expression of Actn1. We have found that Actn1 differential methylation occurs in diverse mouse tissues. Moreover, it is also present in other murine rodents (rat), but not in the orthologous human region. In contrast, we have found no indication of an imprinted effect on gene expression of Actn1 in mice: expression is always biallelic regardless of sex, tissue type, developmental stage or isoform. Therefore, we have identified a novel parent-of-origin dependent differentially methylated region that has no apparent association with imprinted expression of the closest genes. Our findings sound a cautionary note to genome-wide searches on the use of differentially methylated regions for the identification of imprinted genes and suggest that parent-of-origin dependent differential methylation might be conserved for functions other that the control of imprinted expression.
Estimation of Wheat Area in Córdoba, Argentina, with Multitemporal NDVI Data of SPOT-Vegetation  [PDF]
A. C. de la Casa, G. G. Ovando
International Journal of Geosciences (IJG) , 2013, DOI: 10.4236/ijg.2013.410132
Abstract:

Determining the area occupied by a crop is a prerequisite for estimating agricultural production in a region, and such information at present can be generated from satellite remote sensing systems. This study uses multitemporal NDVI images of SPOT-VEGETATION with a 1 km spatial resolution to estimate the wheat area in Córdoba Province, Argentina, and to assess 2 generic digital classification procedures based on crop phenological behavior. The Characteristic Phenology Behavior Method (CPBM) uses the contrast each year between typical values of NDVI variation in the wheat crop season and those of the area not occupied by active vegetation; while the other procedure, the Reference Curve Method (RCM), assesses the correspondence in each pixel between the observed sequence of NDVI from seeding to physiological maturity, compared with 4 curves of reference. The CPBM 2 procedure, which uses the amplitude of NDVI between sowing and heading (ampsh), produces estimates that correlate better with the observed record, with approximately 70% (P < 0.01) of seeding area variability explained by this model in Río Segundo Department, but systematically overestimates the state reports at about 5%. On the other hand, RCM using Curve 1 explains 50% (P < 0.05) of interannual variability of the crop area. Comparing CPBM 1 and CPBM 2 procedures, it was found that replacing ampsh in the model with the minimum NDVI during physiological maturity stage (minpm) produce

Thermal Conditions in Córdoba City, Argentina, during 1960-2010 Period  [PDF]
Antonio C. de la Casa, Olga B. Nasello
American Journal of Climate Change (AJCC) , 2014, DOI: 10.4236/ajcc.2014.32018
Abstract:

The present work analyzes daily minimum (Tmin) and maximum (Tmax) temperature series from Córdoba Observatory weather station, which is located near the center of the city of Córdoba, Argentina, and from the Pajas Blancas and Pilar observatories, in order to have a reference counterpart of regional climate. The air temperature in Córdoba city during 1960-2010 period shows lower/higher frequency of Tmin categories lower/higher than 15°C, with respect to rural thermal conditions. Tmax categories higher/lower than 30°C, in turn, presented higher/lower frequency in the city. While the mean annual Tmin showed a significant positive trend in the entire region in the study period, Tmax presented no significant changes over time. The difference between urban and rural thermal regimes remained uniform throughout the study period, so the process of urbanization does not seem to have changed the Urban heat island status measure from Córdoba Observatory, even though the population of the metropolis has doubled. Although nocturnal thermal conditions have changed over the period, particularly in urban areas, there has been no change in the regime of extreme daytime temperatures across the region. The annual mean Tmin increase is not monotonic, but presents a significant positive partial trend until a breakpoint around 1990, and then becomes neutral or negative and loses significance. For the annual mean

Maculopatía hipotónica diagnosticada por tomografía de coherencia óptica
Martínez de la Casa,JM; García Feijoó,J; Castillo Gómez,A; Macías Benítez,JM; Martín Valdizán,C; García Sánchez,J;
Archivos de la Sociedad Espa?ola de Oftalmología , 2003, DOI: 10.4321/S0365-66912003001000009
Abstract: case report: a 40 year-old man with advanced pigmentary glaucoma in the left eye underwent trabeculectomy. in the immediate postoperative period, visual acuity decreased with no alterations noted on examination of the fundus or on angiofluoresceingraphy. through optical coherence tomography, we were able to make a diagnosis of hypotonic maculopathy and treatment was immediately started. discussion: hypotony maculopathy is one of the most feared complications of filtering eye surgery. in some cases, optical coherence tomography can be useful to confirm its diagnosis non invasively.
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