Cytochemical localization of acid phosphatase in Stigeoclonium tenue (Chaetophorales, Chlorophyceae)

Nonspecific acid phosphatases are a group of enzymes whose activity increases the availability of exogenous and endogenous orthophosphate either through extra- or intracellular hydrolysis of phosphate compounds. Our study demonstrates the activity of acid phosphatases in the filamentous freshwater alga Stigeoclonium tenue. These enzymes were detected following a cerium-based method in which cerium was used as an orthophosphate-capture reagent. In thalli from S. tenue from the natural environment, acid phosphatases were found in the longitudinal cell wall, plasmalemma, and vacuole. In thalli from Bold’s Basal Medium culture, these enzymes were found mainly in the plasmalemma; they were scarce in the cell wall. In the thalli grown in phosphate-enriched culture medium, enzymes were found only in the plasmalemma. The low availability of orthophosphate in the medium seems to induce the transport of these enzymes to the cell wall. Its abundance, on the contrary, seems to attenuate this response without affecting the localization of acid phosphatases in the plasmalemma.Fil: Michetti, Karina Mariel. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Ficología y Micología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Leonardi, Patricia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Caceres, Eduardo Jorge. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Ficología y Micología; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentin

Ultrastructural Alterations in Lepocinclis acus (Euglenophyta) Induced by Medium with High Organic Matter Content

Ultrastructural changes induced by exposure to excess of organic matter were studied in Lepocinclis acus (ex Euglena acus). The cells isolated from the Matanza River, Buenos Aires, Argentina, were grown in soil water medium (SWM). When transferred to medium enriched with Bacteriological Peptone OXOID®, marked body deformation and a significant shortening and widening of the cells was observed. These changes were unexpected in a species with quite rigid cells, a condition previously shown in studies of the pellicle fine structure. Transmission electron microscopy observations suggest that cellular deformation might be facilitated by an increase in strip number, whereas in the original strips normal ultrastructure was maintained. An increase in number and volume of paramylon grains and vacuoles, as well as the presence of membrane whorls in vacuoles was observed. The fine structure of organisms grown in medium with and without organic matter enrichment was compared, and the systematic and ecological importance of morphological changes triggered by cell deformation was discussed.Fil: Conforti, Visitacion Teresa D.. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Ruiz, Laura Beatriz. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Leonardi, Patricia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentin

Cultivo de microalgas: bases científicas para emprendimientos bioenergéticos en el estuario de Bahía Blanca (Bs.As., Argentina)

El Estuario de Bahía Blanca constituye una pieza fundamental para el desarrollo de la Provincia de Buenos Aires y el país. Además de su valor intrínseco, este ambientemuestra numerosas ventajas para futuros emprendimientos relacionados con la producción de biomasa microalgal con fines bioenergéticos. Específicamente, este trabajo presenta resultados relacionados con procesos de cultivo de diatomeas aisladas de dicho Estuario, destinados a la producción de biomasa rica en triglicéridos (TAG), aptos para la obtención de biodiesel, bajo un concepto de biorrefinería. Entre las especies estudiadas, Halamphoracoffeaeformis alcanzó un rendimiento de biomasa de hasta 44,1 g m-2 d-1 en piletas tipo raceway, lo cual sugiere un balance energético positivo. Dentro de este proceso, se obtuvieron porcentajes de aceites de hasta 54,4% de la biomasa y se caracterizaron bioproductos con potenciales aplicaciones industriales, como la sílice y sustancias poliméricas extracelulares. El biodiesel obtenido a partir de aceitemicroalgal presentó un 94% de metilésteres y características acordes con estándares de calidad. Los resultados obtenidos representan una base científica de referencia para fomentar el desarrollo de emprendimientos productivos sustentables en el campo de la bioenergía en la zona de Bahía Blanca, y extensivamente en la Provincia de Buenos Aires

Candida infections, causes, targets and resistance mechanisms. Traditional and alternative antifungal agents

The genus Candida includes about 200 different species, but only a few species are human opportunistic pathogens and cause infections when the host becomes debilitated or immunocompromised. Candida infections can be superficial or invasive. Superficial infections often affect the skin or mucous membranes and can be treated successfully with topical antifungal drugs. However, invasive fungal infections are often life-threatening, probably due to inefficient diagnostic methods and inappropriate initial antifungal therapies. Here, we briefly review our current knowledge of pathogenic species of the genus Candida and yeast infection causes and then focus on current antifungal drugs and resistance mechanisms. An overview of new therapeutic alternatives for the treatment of Candida infections is also provided.Fil: Spampinato, Claudia Patricia. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Centro de Estudios Fotosintéticos y Bioquímicos (i); ArgentinaFil: Leonardi, Darío. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Centro de Estudios Fotosintéticos y Bioquímicos (i); Argentin

Molecular Fingerprints to Identify Candida Species

A wide range of molecular techniques have been developed for genotyping Candida species. Among them, multilocus sequence typing (MLST) and microsatellite length polymorphisms (MLP) analysis have recently emerged. MLST relies on DNA sequences of internal regions of various independent housekeeping genes, while MLP identifies microsatellite instability. Both methods generate unambiguous and highly reproducible data. Here, we review the results achieved by using these two techniques and also provide a brief overview of a new method based on high-resolution DNA melting (HRM). This method identifies sequence differences by subtle deviations in sample melting profiles in the presence of saturating fluorescent DNA binding dyes.Fil: Spampinato, Claudia Patricia. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Centro de Estudios Fotosintéticos y Bioquímicos (i); ArgentinaFil: Leonardi, Darío. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Química Rosario; Argentin

Life history, development and karyology of Klebsormidium nitens (Klebsormidiales, Charophyta)

Se estudiaron las células vegetativas y reproductivas de Klebsormidium nitens, primera cita para la República Argentina. La identificación de la especie se realizó utilizando caracteres morfológicos, hábito de crecimiento, la forma de apertura de los zoosporangios, forma de germinación de las zoósporas y el modo de reproducción. Con respecto a su ciclo de vida, la forma de reproducción más frecuente fue la vegetativa, por simple fragmentación del talo en filamentos cortos. Bajo condiciones adversas se produjeron pseudoramificaciones, a partir de las cuales se originaron nuevos filamentos. La reproducción asexual fue inducida “in vitro”. Zoósporas biflageladas con inserción subapical de los flagelos salieron por un poro lateral. Las zoósporas después de nadar unos minutos retrajeron los flagelos y la germinación fue estrictamente unipolar. La célula basal presentó un rudimentario pie de fijación acompañado de un delicado disco de fijación mucilaginoso; sucesivas mitosis y citocinesis originaron un filamento, el cual pasó a vida planctónica al superar las ocho células. La ausencia de un pie de fijación ha sido considerada hasta el momento un carácter diagnóstico del género; la presencia de dicho pie en K. nitens sugiere que la validez de este carácter para definir el género debería ser revisada. No se verificó reproducción sexual. El número cromosómico hallado en K. nitens fue n = 6. Comparaciones entre el número cromosómico, el tamaño del núcleo y el ancho del filamento con otras especies de Klebsormidium sugiere un número básico x = 6 y a la poliploidía como uno de los procesos involucrados en la evolución de las especies del género.This research is focused on the study of Klebsormidium nitens vegetative and reproductive cells. The following aspects have been considered for the identification of this species, which is a new record for Argentina: morphological characters, growth habits, aperture of zoosporangial cells, zoospore germination patterns and types of reproduction. As regards its life cycle, vegetative multiplication through an easy fragmentation of the thallus into short filaments was the prevailing mode of reproduction. Under adverse conditions, false (or pseudo) branches were formed from which new filaments were born. Asexual reproduction was induced “in vitro”. Biflagellate zoospores with subapically inserted flagella came out from a pore in the lateral wall of sporangial cells. After swimming for a few minutes, zoospores withdrew the flagella, and germination was strictly unipolar. The basal cell presented a rudimentary holdfast with a fine mucilaginous attaching disc. After successive mitosis and cytokinesis a filament was formed which became planctonic after an eight-celled stage. The absence of a holdfast has so far been considered a diagnostic character of the genus, and for this reason the reconsideration of this feature at the generic level has been proposed. Sexual reproduction was not observed. The chromosome number found in K. nitens was n=6. A comparison among chromosome number, nucleus size and filament width with other species of Klebsormidium suggests a basic chromosome number x=6 and polyploidy as one of the processes involved in the evolution of Klebsormidium species.Fil: Sánchez Puerta, María Virginia. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Leonardi, Patricia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur; Argentin

Ultrastructure of multicellular dwarf males with external gametangium in Oedogonium macrandrium (Oedogoniales, Chlorophyta).

This is the first comprehensive ultrastructural study on dwarf males with external gametangia in the genus Oedogonium, from androspore germination to the liberation of mature male gametes. The ultrastructure of the process in O. macrandrium Wittrok is similar to that of Bulbochaete hiloensis (Nordstedt) Tiffany, but with two remarkable differences. In O. macrandrium: 1) instead of a true transverse wall, only condensed mucilage appears between the gametes of each antheridial cell, and 2) the cell wall between the basal cell and the basal most antheridial cell has simple plasmodesmata similar to those present in the transverse walls of vegetative cells, which are absent in B. hiloensis.Fil: D'Amico, Silvana L.. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Ficología y Micología; Argentina;Fil: Leonardi, Patricia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina; Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Ficología y Micología; Argentina;Fil: Caceres, Eduardo Jorge. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina; Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Ficología y Micología; Argentina

Feedstocks for Second-Generation Biodiesel: Microalgae’s Biology and Oil Composition

The solar energy is an inexhaustible source, while other energy reserves, like fossil and nuclear fuels, are limited in quantity and are depleted as years go by. Renewable energy is necessary to replace petroleum-derived fuels. The first generation biofuels, which are produced from oil seeds and crops, are a possible alternative, but they are limited in their capacity to provide all the energy demanded in the world. Therefore, new sources for the sustainable production of renewable energy are being looked for. This concern has promoted the keen interest in developing second generation biofuels, which are produced from other feedstocks, such as microalgal oils (Schenk et al., 2008; Mata et al., 2010). Some microalgal species are capable of producing biomass yields containing high percentages of oils (Aaronson et. al., 1980). In addition, microalgal systems can use low value natural resources, such as arid lands and saline water, thus offering the potential for large biomass energy contributions without competing for prime agricultural or forest land. Most microalgae grow photoautotrophically by using solar energy and mainly carbon dioxide as carbon source. Alternatively, some species can grow heterotrophically or mixotrophically using organic compounds as energy and carbon sources.Fil: Leonardi, Patricia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Popovich, Cecilia Angelines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Damiani, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentin

Fatty Acids from Microalgae: Targeting the Accumulation of Triacylglycerides

Microalgae were originally considered as sources of long-chain polyunsaturated fatty acids (PUFAs), mainly for aquaculture purposes. However, based on the fact that their fatty acids (FA), stored as triacylglycerides (TAG), can be converted into biodiesel via a transesterification reaction, several microalgal species have emerged over the last decade as promising feedstocks for biofuel production. Elucidation of microalgae FA and TAG metabolic pathways is therefore becoming a cutting-edge field for developing transgenic algal strains with improved lipid accumulation ability. Furthermore, many of the biomolecules produced by microalgae can also be exploited. In this chapter, we describe recent advances in the field of FA and TAG pathways in microalgae, focusing in particular on the enzymes involved in FA and TAG synthesis, their accumulation in lipid droplets, and their degradation. Mention is made of potentially high-value products that can be obtained from microalgae, and possible molecular targets for enhancing FA and TAG production are outlined. A summary is provided of transcriptomics, proteomics, and metabolomics of the above-mentioned pathways in microalgae. Understanding the relation between anabolic and catabolic lipid enzyme pathways will provide new insights into biodiesel production and other valuable biomolecules obtained from microalgae

A practical tool for selecting microalgal species for biodiesel production

In the search for energy sources to replace fossil fuels, microalgae have shown promising characteristics. Their cultures have several advantages over the conventional crops used for commercial biodiesel: they have fast growth rates and a high lipid content and can grow in environments unfit for agriculture. However, relatively few species have so far been studied as biodiesel feedstock. In order to facilitate the search for potentially useful species/strains, in this work, a bioprospecting tool based on biomass and oil production process requirements, triacylglyceride content, and biodiesel properties has been developed. For this purpose, an overall score (OS) was proposed as a tool based on biological, economic, and environmental factors. By applying the OS to nine species, we were able to narrow down the number of species within the diatom group, which are potentially suitable for large-scale biodiesel production. Halamphora coffeaeformis, Navicula cincta, and N. gregaria were the species with the highest OS (1.65-1.5). It is expected that this tool will provide a useful contribution to the criteria applied in the selection of microalgal species for large-scale biodiesel production.Fil: Martin, Lucas Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Popovich, Cecilia Angelines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Provincia de Buenos Aires. Dirección General de Cultura y Educación. Universidad Provincial del Sudoeste. Centro de Emprendedorismo y Desarrollo Territorial Sustentable; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Damiani, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Leonardi, Patricia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentin