Abstract: Three-ply plywoods were produced using pine and Eucalyptus northeast Argentinian woods. A no-added formaldehyde biobased-adhesive was used for assembly, based on chemically modified soy protein concentrate. In this work we focused on the relationship between bonding quality parameters of the plywoods and the morphology of the glued line. Wood characteristics such as contact angle, roughness, density and moisture content were measured prior to plywood assembly. Bonding quality parameters (percentage of wood failure and shear strength) of the plywood were measured according to Argentinean standard and the results were evaluated with respect to microscopic observations of the glue joint. Eucalyptus wood was suitable for plywood interior condition applications, while pine barely exceeded the standards imposed by the norm.

In severe environments, the presence of arbuscular mycorrhlzai fungi (AMF) Is essential for plant survival and a balanced ecosystem e. The aim of this work was to characterize the arbuscular mycorrhizal fungi present in algarrobales (Frosopis alba) areas of contrasting humid and semi-arid climatic conditions, Colonia Benitez and Padre Lozano respectively, both in the Parque Chaqueño region in Argentina. The Colonia Benitez and Padre Lozano sites showed significant edaphological differences, the most important being the lower content of organic matter and phosphorus, and the higher percentage of exchangeable sodium in Colonia Benitez, associated with a higher infective capacity and greater mycorrhizal potential of inoculum. Only one species was found in both soils: Acaulospora laevis, typical of arid environments. In the inocula, three species were identified in both sites: Funneliformis mosseae, Rhizophagus intraradices, Claroideoglomus etunicatum; two species were only identified in Colonia Benítez: Septoglomus constrictum and Rhizophagus clarus; and two species were only identified in Padre Lozano: Claroideoglomus claroideum and Diversispora spurca. This is the first study in Argentina to analyze AMF diversity in Frosopis alba areas (algarrobales) and their infectivity in the soils and their inocula.

En ambientes severos, la presencia de hongos micorrícicos arbusculares (HMA) es clave para la supervivencia de las plantas y el balance ecosistémico. El objetivo de este trabajo fue caracterizar los hongos micorrícicos arbusculares presentes en sitios de algarrobales (Frosopis alba) del Parque Chaqueño argentino de condiciones climáticas contrastantes: húmedo, Colonia Benítez, y semiárido, Padre Lozano. Los sitios de Colonia Benítez y Padre Lozano presentaron diferencias edafológicas significativas, destacándose el menor contenido de materia orgánica y fósforo, y el mayor porcentaje de sodio intercambiable en Colonia Benítez, asociados a una mayor capacidad infectiva y mayor potencial micorrícico de inóculo. En los suelos sólo se encontró una especie común: Acaulospora laevis, propia de ambientes áridos. En los inóculos se registraron tres especies en común: Funneliformis mosseae, Rhizophagus intraradices, Claroideoglomus etunicatum; dos especies exclusivas de Colonia Benítez, Septoglomus constrictum y Rhizophagus clarus; y dos especies exclusivas de Padre Lozano, Claroideoglomus claroideum y Diversispora spurca. Este es el primer estudio en Argentina en el cual se reporta la diversidad de HMA en suelos de algarrobales y se mide la infectividad de los suelos y de los inóculos obtenidos a partir de esos suelos.

The aim of this paper was to determine the density (at 12 % m. c.) and the mechanical properties of sawn wood of Argentinean Acacia melanoxylon, and to study the relationship between these properties. Test samples were randomly selected from the material obtained by sawing 20 trees harvested in four different plantations grown in the southeast of Buenos Aires province. Density was determined according to IRAM 9544 and mechanical tests were carried out by following the procedures of ASTM D 143. The mean value obtained for density reached 564 kg.m-3. Strength exhibited the following mean values: 89,9 N.mm-2 in bending, 49,5 N.mm-2 in compression parallel to the grain, 11,7 N.mm-2 in compression perpendicular and 11,6 N.mm-2 in shear parallel. The average hardness reached 45,3 N.mm-2 and the modulus of elasticity in bending exhibited a mean value of 10926 N.mm-2. These results are congruent with those expected for a medium-density wood and they can be considered suitable for uses related to the construction and furniture industries. Coefficients of determination (R²) ranging from 0,73 to 0,87 were found between density and mechanical properties. R² reached 0,72 between modulus of elasticity and bending strength.

El trabajo se enfocó en la determinación de la densidad normal y las propiedades mecánicas de la madera de Acacia melanoxylon implantada en Argentina, y en analizar la relación entre estas variables. El material se seleccionó al azar del obtenido del aserrado de 20 árboles provenientes de cuatro sitios del sudeste de la provincia de Buenos Aires. Se determinó la densidad aparente conforme a la norma IRAM 9544 y los ensayos mecánicos se ejecutaron sobre cuerpos de prueba pequeños y libres de defectos según los lineamientos de la norma ASTM D 143. El valor medio de la densidad fue 564 kg.m-3 y la tensión de rotura mostró los siguientes valores medios: 89,9 N.mm-2 en flexión; 49,5 N.mm-2 en compresión paralela a las fibras; 11,7 N.mm-2 en compresión perpendicular y 11,6 N.mm-2 en corte paralelo. La dureza promedio alcanzó 45,3 N.mm-2 y el módulo de elasticidad en flexión exhibió un valor medio de 10926 N.mm-2. Los resultados de las propiedades mecánicas son los esperados para una madera de densidad media y pueden considerarse adecuados para el uso de la especie en la industria de la construcción y del mueble. Los modelos de regresión entre la densidad y las propiedades mecánicas exhibieron valores del coeficiente de determinación (R²) comprendidos entre 0,70 y 0,87. El modelo de regresión entre el módulo de elasticidad y la resistencia en flexión mostró un valor de R² igual a 0,72.

Three superoxide dismutase isoenzymes of different cellular location were detected in an homogenate of Thrichuris ovis. Each of these molecular forms was purified by differential centrifugation and precipitation with ammonium sulphate, followed by chromatography on DEAE-cellulose and Sephadex G-75 columns. The activity levels of the two molecular forms detected in the mitochondrial (one cyanide sensitive Cu-Zn-SOD and the other cyanide intensitive Mn-Sod were higher than that of the superoxide dismutase detected in the cytoplasmic fraction (cyanid sensitive Cu-Zn-SOD). All the mollecular forms present evident differences to the SODs contained in the host liver. Molecular mass and some of the physical and chemical aproperties of the enzyme was determined for all three molecular forms. An inhibitory effect on the SOD of the parasite an the host was detected with a series of compounds, some of wich markedly inhibited parasite ensyme but not host enzyme.

The inhibitor effect on the Glycogen synthetase (E.C.2.4.1.11) activity by four anthelmintics: Mebendazole, Parbendazole, Albendazole and Thiabendazole was determinated. The most inhibitor effect of Parbendazole on A. suum, F. hepatica and M. expansa, was observed. The lowest inhibitor effect of Thiabendazole, on all cases, was also observed. The aim of our study, and further studies on the same line, are to provide new reports about the unknown locus of actuation of these anthelmintics.

Se ha determinado el effecto inhibidor sobre la actividad Glucogeno sintetasa (E.C.2.41.11) por parte de cuatro antihelminticos: Albendazol, Mebendazol, Parbendazol y Tiabendazol. Observandose que en todos los casos, es el Parbendazol quien ha demostrado un mayor poder inhibidor sobre la glucógeno sintetasa de Ascaris suum, Fasciola hepatica y Moniezia expansa. El Tiabendazol es el anti-helmintico que menor efecto inhibidor ha presentado sobre la enzima en los tres parasitos objeto de nuestro estudio. Con el presente trabajo y otros previstos en la misma linea, se pretende aportar nuevos datos acerca del aun desconocido locus de acción de estos antihelminticos.