oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Search Results: 1 - 10 of 718 matches for " Erasmo Negrete-Abascal "
All listed articles are free for downloading (OA Articles)
Page 1 /718
Display every page Item
SAP Expression in Candida albicans Strains Isolated from Mexican Patients with Vaginal Candidosis  [PDF]
Eric Monroy-Pérez, Gloria Paniagua-Contreras, Felipe Vaca-Paniagua, Erasmo Negrete-Abascal, Sergio Vaca
International Journal of Clinical Medicine (IJCM) , 2013, DOI: 10.4236/ijcm.2013.41006
Abstract:

To determine the frequency and expression of the ten SAP (secreted aspartyl protease) genes in a group of Candida albicans strains isolated from Mexican women suffering from vaginal candidosis, a group of 264 women (age 18 - 57 years) with vaginal infections, predisposed by diabetes mellitus or contraceptive consumption, were evaluated. C. albicans was identified using PCR to amplify the rRNA internal transcribed spacer regions ITS1 and ITS2. The presence of the SAP genes was determined using conventional PCR, and their expression levels were determined using real-time PCR after the C. albicans strains had been grown in reconstituted human vaginal epithelium (RHVE). C. albicans was identified in the samples from 50 women (18.9%). The genotyping frequencies of the SAP genes were as follows: SAP1, 94%; SAP2, 98%; SAP3, 80%; SAP4, 100%; SAP5, 100%; SAP6, 100%; SAP7, 63%; SAP8, 96%; SAP9, 70%; and SAP10, 88%. The most frequently expressed genes in the strains harboring all of the genes were SAP1, 90%; SAP2, 90%; SAP3, 90%; SAP4, 100%; SAP5, 90%; SAP6, 90%; SAP7, 100%; SAP8, 90%; SAP9, 100%; and SAP10, 100%. SAP genes were expressed in the RHVE, suggesting that the Sap proteins play an important role in the pathogenesis of infection.

Adhesion of Gallibacterium anatis to Chicken Oropharyngeal Epithelial Cells and the Identification of Putative Fimbriae  [PDF]
Mónica L. Salgado Lucio, Sergio Vaca, Candelario Vázquez, Edgar Zenteno, Ismael Rea, Víctor M. Pérez-Márquez, Erasmo Negrete-Abascal
Advances in Microbiology (AiM) , 2012, DOI: 10.4236/aim.2012.24064
Abstract: Microbial infections are typically initiated by the colonization of tissues by a specific mechanism that promotes adherence to host cells or tissues. In this work, we characterized the ability of Gallibacterium anatis F149T to express fimbriae that may be involved in mucosal attachment. Using transmission electron microscopy, the fimbriae-like structures could be observed on the surface of negatively stained G. anatis F149T, and these structures were further visualized after being released by physical shaking. When the fimbriae-like structures were separated by SDS-PAGE, the proteins comprising them were isolated and sized at 13 and 25 kDa. G. anatis F149T was able to adhere to chicken oropharyngeal epithelial cells. Adhesion could be completely inhibited by pretreatment of the bacterial cells with trypsin, whereas 25% inhibition was attained after pretreatment with an antiserum against the 13 kDa protein. We demonstrated by immuno-gold electron microscopy that the antibodies from the antiserum were specifically associated with the fimbria-like structures on G. anatis. These results indicated that G. anatis F149T expresses fimbriae that contribute to its adhesion to chicken oropharyngeal epithelial cells and may be important for colonization of the upper respiratory tract.
Virulence Markers in Staphylococcus aureus Strains Isolated from Hemodialysis Catheters of Mexican Patients  [PDF]
Gloria Paniagua-Contreras, Teresita Sáinz-Espu?es, Eric Monroy-Pérez, José Raymundo Rodríguez-Moctezuma, Diego Arenas-Aranda, Erasmo Negrete-Abascal, Sergio Vaca
Advances in Microbiology (AiM) , 2012, DOI: 10.4236/aim.2012.24061
Abstract: Methicillin-resistant Staphylococcus aureus is an increasingly important cause of nosocomial bacterial infections worldwide. S. aureus is responsible for several pathologies, including skin infections, endocarditis, meningitis, deep-tissue ulcers, and sepsis. S. aureus biofilm formation on catheters and other medical devices is a major post-operative concern, because biofilms are often the source of persistent and difficult to treat bacterial infections. While catheter-related S. aureus infections have been reported, the strains responsible for these infections have not been genetically characterized. We genetically characterized S. aureus strains isolated from hemodialysis catheters in Mexican patients. The frequency of 35 genes coding for adhesins, toxins, and other virulence-associated products in the 55 isolated S. aureus strains was determined using PCR, while real-time PCR was used to examine the level of gene expression. Of the 55 S. aureus strains isolated from 109 patients, 45 (81.8%) were determined to be methicillin-resistant. The icaA, rbf, sarA, and agr genes are involved in biofilm formation and bacterial dispersion and were detected in 96.3%, 40.0%, 74.5%, and 100% of S. aureus strains, respectively, and 70.9% of the strains formed a detectable biofilm. Interestingly, 67.2% of the strains contained the icaA, agr, spa, clfA, sdrC, sdrD, sdrE, seg, seh, and sei genes, suggesting that this gene combination is important for successful catheter colonization. The results of this study provide significant insight into the virulence gene make-up of catheter-colonizing S. aureus strains, and will assist in developing a more targeted treatment approach for persistent S. aureus biofilm contamination of medical devices.
Two or more enteropathogens are associated with diarrhoea in Mexican children
Gloria Paniagua, Eric Monroy, Octavio García-González, Javier Alonso, Erasmo Negrete, Sergio Vaca
Annals of Clinical Microbiology and Antimicrobials , 2007, DOI: 10.1186/1476-0711-6-17
Abstract: Faecal samples were obtained from 300 Mexican children diagnosed as positive for diarrhoea, aged > 2 to < 12 years old, and from 80 children matched for age but with no symptoms of the disease (control group). Two multiplex PCR were used to detect Escherichia coli, Salmonella spp., and Shigella spp. In addition, the two protozoan parasites Entamoeba histolytica/Entamoeba dispar and Giardia intestinalis were detected by conventional methods.All diarrhoeal samples were positive for one or more enteropathogens. The most common enteropathogens in diarrhoeal samples were E. histolytica/E. dispar (70.3%), Salmonella (ohio 28.3%; typhimurium 16.3%; infantis 8%; anatum 0.6%; Newport 0.3%), G. intestinalis (33%), E. coli (ETEC 13.3%; EPEC 9.3%; VTEC 8.6%; EIEC 1%) and Shigella spp. (flexneri 1.6%, sonnei 1%). Infections by two (24%) three (16%) and four (12%) pathogens were observed.This study revealed that 52% of the patients were infected by more than one enteropathogen, notably E. histolitica/E. dispar and Salmonella ohio. These results are useful for clinicians to improve the empiric treatment used in such cases.Diarrhoeal diseases constitute a major public health problem, particularly in the developing world, where the rate of mortality and morbidity is very high [1]. The World Health Organization (WHO) has estimated that 1.5 billion episodes of diarrhoea occur every year in developing countries, resulting in 3 million deaths [2]. In Mexico, a governmental study conducted in the year 2003 reported 4556 cases caused by intestinal infectious [3]. The etiological agents of diarrhoea described in epidemiological studies are transmitted as waterborne and foodborne.Some foodborne pathogens have been recently considered as emerging diseases [4], despite the fact they have been known since a long time ago. For example, outbreaks of salmonellosis have been described for many decades, and yet their incidence have increased over the last 25 years. Diarrhoeal infections can be caus
Adherence of Gallibacterium anatis to Inert Surfaces
S. Vaca,E. Monroy,L. Rojas,C. Vazquez,P. Sanchez,E. Soriano-Vargas,A. Miki Bojesen,E. Negrete Abascal
Journal of Animal and Veterinary Advances , 2012, DOI: 10.3923/javaa.2011.1688.1693
Abstract: The genus Gallibacterium includes bacteria of avian origin isolated from a variety of birds. It has been described as an indigenous bacterium to the upper respiratory and lower genital tracts of healthy chickens but it has been also reported associated to different pathological conditions. Microbial infections are initiated by colonization of tissues by a specific mechanism of adherence to host cells. In this research, we evaluated the ability of the G. anatis strains F149T, 12158/5 Salp and the G. genomospecies 1 strain CCM 5974 to adhere to inert surfaces as a possible mechanism promoting biofilm formation. All three strains formed robust biofilms on polystyrene and glass. Adherence was prevented by treating bacterial cells with trypsin, suggesting the participation of proteins in this process. Scanning electron microscopy of G. anatis adherence to glass surface was observed within the 1st 3 h of exposure. Extracellular material, micro-vesicles, filamentous structures and cords were observed as a part of biofilm matrix. The adhesive capacity observed could be an important ability for colonization of tissue surfaces and for allowing Gallibacterium to persist inside its host.
Frequency of vacA, cagA and babA2 virulence markers in Helicobacter pylori strains isolated from Mexican patients with chronic gastritis
Gloria Paniagua, Eric Monroy, Raymundo Rodríguez, Salvador Arroniz, Cristina Rodríguez, José Cortés, Ausencio Camacho, Erasmo Negrete, Sergio Vaca
Annals of Clinical Microbiology and Antimicrobials , 2009, DOI: 10.1186/1476-0711-8-14
Abstract: H. pylori was identified in cultures of gastric biopsies by nested PCR. vacA and cagA genes were detected by multiplex PCR, whereas babA2 gene was identified by conventional PCR.H. pylori-positive biopsies were 143 (60.1%). All H. pylori strains were vacA+; 39.2% were cagA+; 13.3% were cagA+ babA2+ and 8.4% were babA2+. Mexican strains examined possessed the vacA s1, m1 (43.4%), s1, m2 (24.5%), s2, m1 (20.3%) and s2, m2 (11.9%) genotypes.These results show that the Mexican patients suffering chronic gastritis we have studied had a high incidence of infection by H. pylori. Forty four percent (63/143) of the H. pylori strains analyzed in this work may be considered as highly virulent since they possessed two or three of the virulence markers analyzed: vacA s1 cagA babA2 (9.8%, 14/143), vacA s1 babA2 (4.9%, 7/143), and vacA s1 cagA (29.4%, 42/143). However, a statistically significant correlation was not observed between vacAs1, cagA and babA2 virulence markers (χ2 test; P > 0.05).Helicobacter pylori is a spiral-shaped Gram-negative bacterium that has been strongly associated with chronic gastritis and peptic ulcer disease [1,2], and it is a risk factor for gastric cancer [3-5]Three major virulence factors of H. pylori have been described: the cytotoxin-associated gene product (CagA), the vacuolating toxin (VacA) and the adhesion protein BabA2. The cytotoxin-associated gene A (CagA) is a protein with a molecular mass of approximately 125–140 kDa, encoded by the cagA gene, [6,7], that is translocated into gastric epithelial cells by a type IV secretion system, encoded by the cag pathogenicity island (cag PAI) [8]. Inside epithelial cells CagA is phosphorylated on tyrosine residues by host cell Src kinases and stimulates cell-signaling pathways [9], which in turn causes elongation of the cell [10] and activation of proto-oncogenes [11].The vacuolating cytotoxin gene vacA is polymorphic, varying in the signal and middle regions. The main signal region alleles are s1 and s
Characterization of a Gallibacterium Genomospecies 2 Hemagglutinin
S. Ramirez- Apolinar,Fernando M. Guerra-Infante,Maria de J. de Haro-Cruz,C. Salgado- Miranda,E. Madrid- Morales,B.M. Kristensen,A.M. Bojesen,E. Negrete- Abascal,E. Soriano- Vargas
Journal of Animal and Veterinary Advances , 2012, DOI: 10.3923/javaa.2012.556.560
Abstract: The hemagglutinin of Gallibacterium genomospecies 2 strain CCM 5976 was purified by affinity to Glutaraldehyde-Fixed Rabbit Erythrocytes (GFRE) using trypsin-treated bacteria. Two protein bands of approximately 23 and 26 kDa were consistently observed using 12% SDS-PAGE. Other protein bands were also associated to GFRE but disappeared when heated up to 120°C while the hemagglutinating activity remained. Hemagglutinating activity by Gallibacterium was not inhibited by mannose or other carbohydrates tested yet both proteins and carbohydrates were consistently found in samples of purified hemagglutinin. These findings suggest that the Gallibacterium genomospecies 2 hemagglutinin is a glycoprotein-like molecule consisting of at least two subunits of 23 and 26 kDa and that are thermostable, trypsin-resistant and mannose-resistant.
Development of an Indicator Scheme for the Environment Impact Assessment in the Federal District, Mexico  [PDF]
Maria Perevochtchikova, Iskra Alejandra Rojo Negrete
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.43027
Abstract:


In this work is developed a proposal of environment indicators needed for the Environment Impact Assessment (EIA) process in Mexico’s Federal District (FD); through which are authorized the construction and realization of different work actions and activities. The methodology is based on the combination of cabinet and field work, performed in three stages. In the first, a documental review was carried out within the topic of Environment Impact (EI), the EIA and the study area, with a subsequent analysis of the environment indicators at an international, national and regional scale. In the second, the systematization of information was performed for the sixteen study cases at a local scale and the organization and analysis of a data base with the allotted information. And in the last stage, a field work was realized with participative observations in three verification sites and interview applications to the principal actors of the EIA process. These results allowed: to determine the main limitations within the EIA process (methodological, technical and operational), to propose an indicators scheme, and to formulate recommendations focused on the improvement of this Environment Public Policy instrument.


Deformación andina en la cuenca de Choromoro, NO de Tucumán: estilo estructural combinado Andean deformation in the Choromoro Basin, NW Tucuman: mixed structural styles
L. del V. Abascal
Revista de la Asociación Geológica Argentina , 2005,
Abstract: La estructura de la depresión tectónica de Choromoro, situada en la parte norte de la provincia de Tucumán, es el resultado de la compresión cenozoica que imprimió un estilo combinado de deformación, representado por una tectónica que involucra al basamento y otra que afecta sólo a la cobertura sedimentaria. Ambas son sincrónicas y se encuentran superpuestas. El estilo de cobertura o de piel delgada se desarrolla en el interior de la cuenca, asociado a una superficie de despegue situada a una profundidad entre los 2,5 y 3 km, probablemente en pelitas del Subgrupo Balbuena (Formación Lumbrera). La deformación que involucra al basamento ha generado láminas delimitadas por cabalgamientos, despegadas de un substrato profundo a lo largo de una superficie ubicada aproximadamente a 20 km de profundidad. The Choromoro Basin is a tectonic depression in north-western Tucuman Province. Its present structural geometry is the result of Cenozoic compression that yielded a combined deformation style on the Neogene deposits. This structural style is represented by thick- and thin-skinned tectonics, superimposed in time and space. The thin-skinned style developed in the interior of the basin, associated with a detachment surface at a depth of 2.5 to 3 km, probably in shales of the Balbuena Subgroup (Lumbrera Formation). The thickskinned deformation relates to a deep detachment at a depth of about 20 km, incorporating metamorphic basement blocks, bounded by high-angle reverse faults and tilted with the cover strata.
Los cuentos de Carmen de Burgos publicados en La Esfera. Ilustración Mundial (1914-1930)
Arbona Abascal, Guadalupe
Arbor : Ciencia, Pensamiento y Cultura , 2010, DOI: 10.3989/arbor.2010.extrajunion3010
Abstract: This paper addresses the study of nine short-stories by Carmen de Burgos, Colombine, published in the arts magazine La Esfera. Ilustración de Madrid between 1914 and 1930. All of them have descriptive value and are written in different styles corresponding to the spaces depicted in them. This allows a classification in three groups according to the main traits of the stories. The first group is within a poetic naturalism. The second group is representative of a critical realism perspective, while the third one, more innovative, belongs in a humorous-cosmopolitan realism. All nine short-stories express a socially critical view, structurally ordered, and which reveals itself as the meaning of the texts. Este trabajo aborda el estudio de nueve cuentos de Carmen de Burgos, Colombine, publicados en la revista de arte La Esfera. Ilustración Mundial entre 1914 y 1930. Todos ellos tienen un valor descriptivo y se modulan con diferentes estilos a partir de la visión del espacio. Esto permite una clasificación según los rasgos predominantes de cada uno de ellos: los primeros se enmarcan en una tendencia al naturalismo poético, los segundos son representativos de un realismo-crítico y los terceros, más innovadores, se inscriben en un realismo humorístico-cosmopolita. En todos ellos se descubre un fondo de crítica social, que se ordena en una estructura y se revela como el significado de los textos.
Page 1 /718
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.