Determinantes perceptuales de la intención de uso de Internet para el desarrollo del capital humano

En el marco de la Teoría del Capital Humano (TCH) y las Tecnologías de Información y Comunicación (TIC) se plantea la relación entre el uso de Internet y las percepciones de utilidad, facilidad y autoeficacia. Los resultados muestran que el determinante principal del uso de Internet es la percepción de utilidad (β = .46). El modelo obtuvo un adecuado ajuste con respecto al modelo de relaciones hipotéticas entre las variables perceptuales y actitudinales sobre la variable intencional. Se discuten las implicaciones del modelo en torno al desarrollo del capital humano y satisfacción del cliente en los ambientes laborales

Kex2 protease converts the endoplasmic reticulum α1,2-mannosidase of Candida albicans into a soluble cytosolic form

Cytosolic α-mannosidases are glycosyl hydrolases that participate in the catabolism of cytosolic free N-oligosaccharides. Two soluble α-mannosidases (E-I and E-II) belonging to glycosyl hydrolases family 47 have been described in Candida albicans. We demonstrate that addition of pepstatin A during the preparation of cell homogenates enriched α-mannosidase E-I at the expense of E-II, indicating that the latter is generated by proteolysis during cell disruption. E-I corresponded to a polypeptide of 52 kDa that was associated with mannosidase activity and was recognized by an anti-α1,2-mannosidase antibody. The N-mannan core trimming properties of the purified enzyme E-I were consistent with its classification as a family 47 α1,2-mannosidase. Differential density-gradient centrifugation of homogenates revealed that α1,2-mannosidase E-I was localized to the cytosolic fraction and Golgi-derived vesicles, and that a 65 kDa membrane-bound α1,2-mannosidase was present in endoplasmic reticulum and Golgi-derived vesicles. Distribution of α-mannosidase activity in a kex2Δ null mutant or in wild-type protoplasts treated with monensin demonstrated that the membrane-bound α1,2-mannosidase is processed by Kex2 protease into E-I, recognizing an atypical cleavage site of the precursor. Analysis of cytosolic free N-oligosaccharides revealed that cytosolic α1,2-mannosidase E-I trims free Man8GlcNAc2 isomer B into Man7GlcNAc2 isomer B. This is believed to be the first report demonstrating the presence of soluble α1,2-mannosidase from the glycosyl hydrolases family 47 in a cytosolic compartment of the cell

Heterologous expression and biochemical characterization of an 1,2-mannosidase encoded by the Candida albicans MNS1 gene

Protein glycosylation pathways, commonly found in fungal pathogens, offer an attractive new area of study for the discovery of antifungal targets. In particular, these post-translational modifications are required for virulence and proper cell wall assembly in Candida albicans , an opportunistic human pathogen. The C. albicans MNS1 gene is predicted to encode a member of the glycosyl hydrolase family 47, with 1,2-mannosidase activity. In order to characterise its activity, we first cloned the C. albicans MNS1 gene into Escherichia coli, then expressed and purified the enzyme. The recombinant Mns1 was capable of converting a Man9GlcNAc2 N-glycan core into Man8GlcNAc2 isomer B, but failed to process a Man5GlcNAc2-Asn N-oligosaccharide. These properties are similar to those displayed by Mns1 purified from C. albicansmembranes and strongly suggest that the enzyme is an α1,2-mannosidase that is localised to the endoplasmic reticulum and involved in the processing of N-linked mannans. Polyclonal antibodies specifically raised against recombinant Mns1 also immunoreacted with the soluble α1,2-mannosidases E-I and E-II, indicating that Mns1 could share structural similarities with both soluble enzymes. Due to the high degree of similarity between the members of family 47, it is conceivable that these antibodies may recognise α1,2-mannosidases in other biological systems as well

Dimensiones utilitarista y eficientista del uso de internet

Una revisión de los estudios relativos al uso de Internet permitió deducir la prevalencia de dos dimensiones: utilidad y eficiencia. A partir de tales hechos, el presente trabajo se propuso establecer las propiedades psicométricas de un instrumento que midiera ambas dimensiones. Para tal efecto, se llevó a cabo una investigación transversal y correlacional con una muestra no probabilística de 188 ciberusuarios. Se construyó una escala ad hoc para establecer su normalidad (Curtosis multivariable = .321; Boostrap = .000), confiabiliad (alfa = ,744), validez (KMO = .673; p = .000), estructura (X2 = 9.124; 5gl; p = .000; GFI = .910; AGFI = .911; CFI = .975; RMSEA = .009; RMR = .007). Los resultados permitieron corroborar la hipótesis de dos dimensiones de uso de Internet, aunque los valores de disturbio y error sugieren la inclusión de otras variables en el modelo. Tales hallazgos fueron discutidos en referencia al estado del arte

Purification and biochemical characterisation of endoplasmic reticulum α1,2-mannosidase from Sporothrix schenckii

Alpha 1,2-mannosidases from glycosyl hydrolase family 47 participate in N-glycan biosynthesis. In filamentous fungi and mammalian cells, α1,2-mannosidases are present in the endoplasmic reticulum (ER) and Golgi complex and are required to generate complex N-glycans. However, lower eukaryotes such Saccharomyces cerevisiae contain only one α1,2-mannosidase in the lumen of the ER and synthesise high-mannose N-glycans. Little is known about the N-glycan structure and the enzyme machinery involved in the synthesis of these oligosaccharides in the dimorphic fungus Sporothrix schenckii . Here, a membrane-bound α-mannosidase from S. schenckii was solubilised using a high-temperature procedure and purified by conventional methods of protein isolation. Analytical zymograms revealed a polypeptide of 75 kDa to be responsible for enzyme activity and this purified protein was recognised by anti-α1,2-mannosidase antibodies. The enzyme hydrolysed Man9GlcNAc2 into Man8GlcNAc2 isomer B and was inhibited preferentially by 1-deoxymannojirimycin. This α1,2-mannosidase was localised in the ER, with the catalytic domain within the lumen of this compartment. These properties are consistent with an ER-localised α1,2-mannosidase of glycosyl hydrolase family 47. Our results also suggested that in contrast to other filamentous fungi, S. schenckii lacks Golgi α1,2-mannosidases and therefore, the processing of N-glycans by α1,2-mannosidases is similar to that present in lower eukaryotes

Determinantes perceptuales de la intención de uso de Internet para el desarrollo del capital humano

En el marco de la Teoría del Capital Humano (TCH) y las Tecnologías de Información y Comunicación (TIC) se plantea la relación entre el uso de Internet y las percepciones de utilidad, facilidad y autoeficacia. Los resultados muestran que el determinante principal del uso de Internet es la percepción de utilidad (β = .46). El modelo obtuvo un adecuado ajuste con respecto al modelo de relaciones hipotéticas entre las variables perceptuales y actitudinales sobre la variable intencional. Se discuten las implicaciones del modelo en torno al desarrollo del capital humano y satisfacción del cliente en los ambientes laborales

Dimensiones utilitarista y eficientista del uso de internet

Una revisión de los estudios relativos al uso de Internet permitió deducir la prevalencia de dos dimensiones: utilidad y eficiencia. A partir de tales hechos, el presente trabajo se propuso establecer las propiedades psicométricas de un instrumento que midiera ambas dimensiones. Para tal efecto, se llevó a cabo una investigación transversal y correlacional con una muestra no probabilística de 188 ciberusuarios. Se construyó una escala ad hoc para establecer su normalidad (Curtosis multivariable = .321; Boostrap = .000), confiabiliad (alfa = ,744), validez (KMO = .673; p = .000), estructura (X2 = 9.124; 5gl; p = .000; GFI = .910; AGFI = .911; CFI = .975; RMSEA = .009; RMR = .007). Los resultados permitieron corroborar la hipótesis de dos dimensiones de uso de Internet, aunque los valores de disturbio y error sugieren la inclusión de otras variables en el modelo. Tales hallazgos fueron discutidos en referencia al estado del arte