Fungal biomass estimation in soils from southwestern Buenos Aires province (Argentina) using calcofluor white stain

Los microorganismos del suelo son vitales para el correcto funcionamiento de los ecosistemas, principalmente por su rol en el ciclado de nutrientes. La intensificación del uso del suelo y las prácticas agrícolas alteran negativamente la actividad microbiana. La biomasa fúngica es uno de los parámetros más utilizados para estudiar el impacto de las actividades agrícolas en la estructura y funcionamiento del suelo. El objetivo del presente trabajo fue estimar la biomasa fúngica en un suelo del sudoeste bonaerense con el fin de obtener valores de referencia que permitan usar este parámetro como un indicador de cambios en el ecosistema y por otro lado, demostrar que la metodología empleada es sensible a las variaciones en las condiciones climáticas. Se colectaron muestras de suelos durante dos años consecutivos. Se prepararon frotis de suelo y se tiñeron con soluciones de distintas concentraciones de blanco de calcoflúor y luego se estimó la biomasa fúngica observando los frotis con microscopio de epifluorescencia. Los valores de biomasa fúngica estimados variaron entre 2,23 y 26,89 µg Cfúngico/g de suelo y estuvieron dentro del rango esperable para el tipo de suelo estudiado. La biomasa fúngica mostró una relación positiva con la temperatura y las precipitaciones. La metodología empleada resultó ser confiable, repetible, y sensible a cambios en las condiciones climáticas. Los resultados podrían usarse como valores de referencia para estudiar en la biomasa fúngica de suelos bajo distintas condiciones y emplearse como indicadores del impacto de las distintas prácticas agrícolas sobre el ecosistema.Soil microorganisms are vital for ecosystem functioning because of the role they play in soil nutrient cycling. Agricultural practices and the intensification of land use have a negative effect on microbial activities and fungal biomass has been widely used as an indicator of soil health. The aim of this study was to analyze fungal biomass in soils from southwestern Buenos Aires province using direct fluorescent staining and to contribute to its use as an indicator of environmental changes in the ecosystem as well as to define its sensitivity to weather conditions. Soil samples were collected during two consecutive years. Soil smears were prepared and stained with two different concentrations of calcofluor, and the fungal biomass was estimated under an epifluorescence microscope. Soil fungal biomass varied between 2.23 and 26.89 μg fungal C/g soil, being these values in the range expected for the studied soil type. The fungal biomass was positively related to temperature and precipitations. The methodology used was reliable, standardized and sensitive to weather conditions. The results of this study contribute information to evaluate fungal biomass in different soil types and support its use as an indicator of soil health for analyzing the impact of different agricultural practices.Fil: Vazquez, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiarida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiarida; ArgentinaFil: Amodeo, Martín Raúl. Universidad Nacional del Sur. Departamento de Biologia, Bioquimica y Farmacia. Grupo de Estudios en Conservacion y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bianchinotti, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiarida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiarida; Argentin

Endosymbiotic and host proteases in the digestive tract of the invasive snail Pomacea canaliculata: diversity, origin and characterization

Digestive proteases of the digestive tract of the apple snail Pomacea canaliculata were studied. Luminal protease activity was found in the crop, the style sac and the coiled gut and was significantly higher in the coiled gut. Several protease bands and their apparent molecular weights were identified in both tissue extracts and luminal contents by gel zymography: (1) a 125 kDa protease in salivary gland extracts and in the crop content; (2) a 30 kDa protease throughout all studied luminal contents and in extracts of the midgut gland and of the endosymbionts isolated from this gland; (3) two proteases of 145 and 198 kDa in the coiled gut content. All these proteases were inhibited by aprotinin, a serine-protease inhibitor, and showed maximum activity between 30C and 35C and pH between 8.5 and 9.5. Tissue L-alanine-N-aminopeptidase activity was determined in the wall of the crop, the style sac and the coiled gut and was significantly higher in the coiled gut. Our findings show that protein digestion in P. canaliculata is carried out through a battery of diverse proteases originated from the salivary glands and the endosymbionts lodged in the midgut gland and by proteases of uncertain origin that occur in the coiled gut lumen.Fil: Godoy, Martín Sergio. Instituto Nacional de Tecnologia Agropecuaria. Centro Nacional de Inv. Agropecuarias. Centro de Inv. Agropecuarias. Instituto de Fisiologia y Recursos Geneticos Vegetales; Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Mendoza. Instituto Histologia y Embriologia D/mend Dr.m.burgos;Fil: Castro-Vasquez, Alfredo. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Mendoza. Instituto Histologia y Embriologia D/mend Dr.m.burgos; Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Instituto Nacional de Tecnologia Agropecuaria. Centro Nacional de Inv. Agropecuarias. Centro de Inv. Agropecuarias. Instituto de Fisiologia y Recursos Geneticos Vegetales;Fil: Vega, Israel Aníbal. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Mendoza. Instituto Histologia y Embriologia D/mend Dr.m.burgos; Instituto Nacional de Tecnologia Agropecuaria. Centro Nacional de Inv. Agropecuarias. Centro de Inv. Agropecuarias. Instituto de Fisiologia y Recursos Geneticos Vegetales

Síntesis y caracterización de nanosílices funcionalizadas injertadas con 3-aminopropil trietoxisilano para ser utilizadas en adhesivos de poliuretano

En este trabajo se presentan los resultados obtenidos al modificar superficialmente una sílice pirogénica hidrófila comercial, con una superficie específica de 200 m2 /g, a la que se le injertó 3-aminopropiltrietoxisilano. La nanosílice modificada se añadió a adhesivos de poliuretano termoplástico en metiletilcetona. El material obtenido se caracterizó mediante sus propiedades mecánicas, térmicas, reológicas y adhesivas. Los resultados obtenidos se compararon con los de adhesivos de poliuretano sin sílice y con sílice sin modificar, preparados bajo las mismas condiciones experimentales.Fil: Vega Baudrit, José. Universidad Nacional. Escuela de Química. Laboratorio de Polímeros; Costa RicaFil: Sibaja Ballestero, María. Universidad Nacional. Escuela de Química. Laboratorio de Polímeros; Costa RicaFil: Martín Martinez, José Miguel. Universidad de Alicante. Departamento de Química Inorgánica. Laboratorio de Adhesión y Adhesivos; EspañaFil: Vazquez, Patricia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentin

Effect of Symmetrically Switched Rectifier Topologies on the Frequency Regulation of Standalone Micro-Hydro Power Plants

Micro-hydro power plants (μHPPs) are a major energy source in grid-isolated zones because they do not require reservoirs and dams to be built. μHPPs operate in a standalone mode, but a continuously varying load generates voltage unbalances and frequency fluctuations which can cause long-term damage to plant components. One method of frequency regulation is the use of alternating current-alternating current (AC-AC) converters as an electronic load controller (ELC). The disadvantage of AC-AC converters is reactive power consumption with the associated decrease in both the power factor and the capacity of the alternator to deliver current. To avoid this disadvantage, we proposed two rectifier topologies combined with symmetrical switching. However, the performance of the frequency regulation loop with each topology remains unknown. Therefore, the objective of this work was to evaluate the performance of the frequency regulation loop when each topology, with a symmetrical switching form, was inserted. A MATLAB® model was implemented to simulate the frequency loop. The results from a μHPP case study in a small Cuban rural community called ‘Los Gallegos’ showed that the performance of the frequency regulation loop using the proposed topologies satisfied the standard frequency regulation and increased both the power factor and current delivery capabilities of the alternator.This contribution is a result of a cooperation between the APlied Electronic Research Team (APERT) at the University of the Basque Country (UPV/EHU), supported by the Department of Education of the Basque Government, within the fund for research groups of the Basque university system IT978-16, the Power Electronics Control in Energy and Motion Systems group (PECEM) at the University of Oriente, and the IRIS project for Cuban energy transformation. Integration of Renewable Intermittent Sources in the power system (IRIS, 2019-2022) is financed by Academy of Science in Finland, Grant/Award Number 320229. The authors of this article gratefully acknowledge these financers and project partners