Técnicas para la gestión del ancho de banda en la Wan con soporte en Routers Cisco 2600

Se presenta una recopilación de las técnicas para la gestión del ancho de banda en la WAN, agrupadas según el enfoque que utilizan para resolver el problema de desempeño de la red. La inclusión dentro de una agrupación no es estricta lo que implica que una técnica puede estar involucrada en varias agrupaciones. Luego se estudian y documentan las capacidades de la familia de routers Cisco 2600 para soportar protocolos WAN (ATM, Frame Relay, RDSI, SMDS y X.25). Se muestra en forma detallada cómo simular o emular una implementación completa del protocolo Frame Relay y la técnica de gestión del ancho de banda Frame Relay Traffic Shaping, en los routers y routers que actúan como switches Frame Relay, al configurar las dos interfases seriales con que actualmente disponen los routers del laboratorio de redes de la Universidad Tecnológica de Bolívar. Al final se encuentran las conclusiones del por qué se realizaron las prácticas de laboratorio utilizando Frame Relay y notas acerca de la recopilación de las técnicas de gestión del ancho de banda en la WANIncluye bibliografí

Interacción entre genotipos de frijol y aislamiento de Rhizoctonia solani Kuhn. heredabilidad de la resistencia a la mustia hilachosa Thanatephorus cucumeris (Frank) (Donk) en cuItivares y poblaciones F, y F2 de frijol común Phaseolus vulgaris L.

Se inocularon genotipos mesoamericanos y andinos de frijol común con micelio de Thanalephorus cucumeris (Frank), Donk, con el objeto de determinar: l. La interacción entre diferentes aislamientos de Rhizoclonia solani, Kuhn y genotipos de frijol de dos acervos genéticos diferentes; 2. La heredabilidad de la resistencia a la mustia hilachosa; 3. La complementación génica que existe entre el acervo mesoamericano y andino respectivamente. Los resultados encontrados enel presente estudio fueron los siguientes: Las cepas varían dependiendo de su lugar de origen. Así las cepas de Colombia y República Dominicana causan el menor daño a las plantas de frijol, el aislamiento Panamá #1 es moderadamente lento y los de Panamá #2 y Costa Rica son los que mayor daño cau-san a este cultivo. La cepa RS-32-Cr resultó ser la más virulenta de todas. La heredabilidad mostrada por los cruzamientos fue alta, lo que nos indica que si existe complementación génica entre el acervo mesoamericano y andino respectivamente. El cruzamiento AFR-251 x BAT-1155, en forma directa y recíproca, mostraron diferencias tanto en la F1 como en la F2 lo que nos indica que la resistencia a la enfermedad está controlada tanto por gcnes del citoplasma corno por genes del núcleo. El tipo de resistencia que mostraron los diferentes cruzamientos evaluados fue el de resistencia horizontal y no el de resistencia vertical

Presence of necrotic strains of Potato virus Y in Mexican potatoes

Correction to Ramírez-Rodríguez VR, Frías-Treviño G, Aviña-Padilla K, Silva-Rosales L, Martínez-Soria JP: Presence of necrotic strains of Potato virus Y in Mexican potatoes. Virology Journal 2009, 6:4

Molecular Diagnosis of Invasive Aspergillosis

Invasive aspergillosis (IA) is a disease that is difficult to manage and is associated with a significantly high morbidity and mortality, caused by different species of the genus Aspergillus, and closely related to immunocompromised patients; thus, it is important to understand the distribution and molecular epidemiology of the species causing this disease. Even though Aspergillus fumigatus sensu stricto is the most common species that cause IA, in recent years, there has been an increase in the number of species in the different sections which makes the diagnosis of this invasive fungal disease a great challenge. Conventional tests for the diagnosis of IA present limitations in sensitivity and specificity, while molecular tests have the potential to improve diagnosis by offering a more sensitive and rapid identification, but they are not yet standardized for reliable use in clinic. Nevertheless, there are some tests for the presumptive diagnosis of aspergillosis which, although are not specific for the identification of species, have been decisive in the case of IA. Among these are the Galactomannan test (GM), the Beta-D-glucan assay and volatile organic compounds (VOCs) testing. In this chapter, the recent advances and challenges in the molecular diagnosis of IA are revised

Effect of cholesterol on the hydration properties of ester and ether lipid membrane interphases

Fluorescence spectroscopy and Molecular Dynamics results show that cholesterol reduces water along the chains in ether lipids by changing the water distribution pattern between tightly and loosely bound water molecules. Water distribution was followed by emission spectra and generalized polarization of 6-dodecanoyl-2-dimethyl aminonaphthalene (Laurdan) inserted in 1,2-dimiristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-di-O-tetradecyl-sn-glycero-3-phosphocholine (14: 0 Diether PC) membranes. Molecular Dynamics simulations indicate that the action of cholesterol could be different in ether PC in comparison to ester PC. In addition, Cholesterol seems to act “per se” as an additional hydration center in ether lipids. Regardless of the phase state, cholesterol both in DMPC and 14:0 Diether PC vesicles, changed the distribution of water molecules decreasing the dipole relaxation of the lipid interphase generating an increase in the non-relaxable population. Above 10% Cholesterol/14:0 Diether PC ratio vesicles' interphase present an environment around Laurdan molecules similar to that corresponding to ester PC.Fil: Pérez, Hugo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Centro de Investigación en Biofísica Aplicada y Alimentos. - Universidad Nacional de Santiago del Estero. Centro de Investigación en Biofísica Aplicada y Alimentos; ArgentinaFil: Alarcon, Laureano Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Verde, Alejandro Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Appignanesi, Gustavo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Gimenez, Rodrigo Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Centro de Investigación en Biofísica Aplicada y Alimentos. - Universidad Nacional de Santiago del Estero. Centro de Investigación en Biofísica Aplicada y Alimentos; ArgentinaFil: Disalvo, Edgardo Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Centro de Investigación en Biofísica Aplicada y Alimentos. - Universidad Nacional de Santiago del Estero. Centro de Investigación en Biofísica Aplicada y Alimentos; ArgentinaFil: Frías, María de los Ángeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Centro de Investigación en Biofísica Aplicada y Alimentos. - Universidad Nacional de Santiago del Estero. Centro de Investigación en Biofísica Aplicada y Alimentos; Argentin

Usefulness of a multiplex PCR for the rapid identification of Candida glabrata species complex in Mexican clinical isolates

Candida glabrata complex includes three species identified through molecular biology methods: C. glabrata sensu stricto, C. nivariensis and C. bracarensis. In Mexico, the phenotypic methods are still used in the diagnosis; therefore, the presence of C. nivariensis and C. bracarensis among clinical isolates is still unknown. The aim of this study was to evaluate the utility of a multiplex PCR for the identification of the C. glabrata species complex. DNA samples from 92 clinical isolates that were previously identified through phenotypic characteristics as C. glabrata were amplified by four oligonucleotides (UNI-5.8S, GLA-f, BRA-f, and NIV-f) that generate amplicons of 397, 293 and 223-bp corresponding to C. glabrata sensu stricto, C. nivariensis, and C. bracarensis, respectively. The amplicon sequences were used to perform a phylogenetic analysis through the Maximum Likelihood method (MEGA6), including strains and reference sequences of species belonging to C. glabrata complex. In addition, recombination and linkage disequilibrium were estimated (DnaSP version 5.0) for C. glabrata sensu stricto isolates. Eighty-eight isolates generated a 397-bp fragment and only in one isolate a 223-bp amplicon was observed. In the phylogenetic tree, the sequences of 397-bp were grouped with C. glabrata reference sequences, and the sequence of 223-bp was grouped with C. bracarensis reference sequences, corroborating the PCR identification. The number of recombination events for the isolates of C. glabrata sensu stricto was zero, suggesting a clonal population structure. Three isolates that did not amplify any of the expected fragments were identified as Saccharomyces cerevisiae through the sequencing of the D1/D2 domain region within the 28S rDNA gene. The multiplex PCR is a fast, cost-effective and reliable tool that can be used in clinical laboratories to identify C. glabrata complex species

Analysis of a new strain of Euphorbia mosaic virus with distinct replication specificity unveils a lineage of begomoviruses with short Rep sequences in the DNA-B intergenic region

<p>Abstract</p> <p>Background</p> <p><it>Euphorbia mosaic virus </it>(EuMV) is a member of the SLCV clade, a lineage of New World begomoviruses that display distinctive features in their replication-associated protein (Rep) and virion-strand replication origin. The first entirely characterized EuMV isolate is native from Yucatan Peninsula, Mexico; subsequently, EuMV was detected in weeds and pepper plants from another region of Mexico, and partial DNA-A sequences revealed significant differences in their putative replication specificity determinants with respect to EuMV-YP. This study was aimed to investigate the replication compatibility between two EuMV isolates from the same country.</p> <p>Results</p> <p>A new isolate of EuMV was obtained from pepper plants collected at Jalisco, Mexico. Full-length clones of both genomic components of EuMV-Jal were biolistically inoculated into plants of three different species, which developed symptoms indistinguishable from those induced by EuMV-YP. Pseudorecombination experiments with EuMV-Jal and EuMV-YP genomic components demonstrated that these viruses do not form infectious reassortants in <it>Nicotiana benthamiana</it>, presumably because of Rep-iteron incompatibility. Sequence analysis of the EuMV-Jal DNA-B intergenic region (IR) led to the unexpected discovery of a 35-nt-long sequence that is identical to a segment of the <it>rep </it>gene in the cognate viral DNA-A. Similar short <it>rep </it>sequences ranging from 35- to 51-nt in length were identified in all EuMV isolates and in three distinct viruses from South America related to EuMV. These short <it>rep </it>sequences in the DNA-B IR are positioned downstream to a ~160-nt non-coding domain highly similar to the CP promoter of begomoviruses belonging to the SLCV clade.</p> <p>Conclusions</p> <p>EuMV strains are not compatible in replication, indicating that this begomovirus species probably is not a replicating lineage in nature. The genomic analysis of EuMV-Jal led to the discovery of a subgroup of SLCV clade viruses that contain in the non-coding region of their DNA-B component, short <it>rep </it>gene sequences located downstream to a <it>CP</it>-promoter-like domain. This assemblage of DNA-A-related sequences within the DNA-B IR is reminiscent of polyomavirus microRNAs and could be involved in the posttranscriptional regulation of the cognate viral <it>rep </it>gene, an intriguing possibility that should be experimentally explored</p

Circulating Tumor Cells in Hepatocellular Carcinoma: A Comprehensive Review and Critical Appraisal

Hepatocellular carcinoma (HCC) is the fifth most common neoplasm and a major cause of cancer-related death worldwide. There is no ideal biomarker allowing early diagnosis of HCC and tumor surveillance in patients receiving therapy. Liquid biopsy, and particularly circulating tumor cells (CTCs), have emerged as a useful tool for diagnosis and monitoring therapeutic responses in different tumors. In the present manuscript, we evaluate the current evidence supporting the quantitative and qualitative assessment of CTCs as potential biomarkers of HCC, as well as technical aspects related to isolation, identification, and classification of CTCs. Although the dynamic assessment of CTCs in patients with HCC may aid the decision-making process, there are still many uncertainties and technical caveats to be solved before this methodology has a true impact on clinical practice guidelines. More studies are needed to identify the optimal combination of surface markers, to increase the efficiency of ex-vivo expansion of CTCs, or even to target CTCs as a potential therapeutic strategy to prevent HCC recurrence after surgery or to hamper tumor progression and extrahepatic spreading