Preparación de agarosa a partir de agar comercial

Se preparó agarosa con un rendimiento del 50% a partir de agar comercial. El producto comercial se sometió a una serie de procesos de lavado, purificación y finalmente se trató con gel de hidróxido de aluminio

The Effects of NO–\ud 3 Supply on Mazzaella laminarioides (Rhodophyta,\ud Gigartinales) from Southern Chile

The effects of nitrate supply on growth, pigments, mycosporine-like amino acids (MAAs), C:N ratios and carrageenan yield were investigated in Mazzaella laminarioides cultivated under solar radiation. This species is economically important in southern Chile where an increase of nitrogen in coastal waters is expected as a consequence of salmon aquaculture activity. Apical segments were cultivated in enriched seawater with five different inline image concentrations (0, 0.09, 0.18, 0.38 and 0.75 mm) during 18 days. Although phycoerythrin and phycocyanin content, as well as C:N ratios, were reduced in the control treatment (without inline image supply), when compared to inline image treatments, total MAA concentration, carrageenan yield and growth rates were similar in all tested conditions. Nevertheless, during the experiment, an important synthesis of mycosporine-glycine took place in a nitrate concentration-dependent manner, with accumulation being saturated around 0.18 mm of nitrate. These results indicate that exposure to high inline image concentration of more than 100 times the values observed in the nature did not impair the photoprotection system, as determined by MAAs, nor did it have a deleterious effect on growth or carrageenan yield of M. laminarioides, a late successional species from Chile.This study was part of a PhD thesis presented by the Nelso P. Navarro to the Graduate Program in Botany, Instituto de Biociências, São Paulo, Brazil. The author is grateful to CONICYT-Chile for a doctoral fellowship. This work was financed in part by Projects CGL08-05407 C03-01 and RNM5750 by Spanish and Andalusian governments, respectively, and by DICYT, Universidad de Santiago de Chile

Análisis de los extractos etanólicos de Gelidium rex y Gelidium lingulatum

Se analizó por cromatografía en papel y cromatografía gas-liquido el contenido de aminoácidos libres e hidratos de carbono de peso molecular bajo de los extractos etanólicos de las algas rojas Gelidium rex y Gelidium lingulatum. Para Gelidium lingulatum, el aminoácido encontrado en mayor proporción es el ácido glutámico mientras que para Gelidium rex el ácido glutámico y alanina constituyen los aminoácidos encontrados en mayor proporción. El contenido de hidratos de carbono de peso molecular bajo es similar en ambos extractos

Anthocyanin composition in aged Chilean Cabernet Sauvignon red wines

Anthocyanins in aged Cabernet Sauvignon red wines were studied by HPLC-MS. The major anthocyanin in 6, 7, and 8 year old red wine extracts was the dimer vitisin A produced by condensation of malvidin-3-O-glucoside mediated by pyruvic acid. In aged wine, the content of malvidin-3-O-glucoside decreased with age with a concomitant increase of vitisin A. The latter is accompanied by several condensation products with molecular weight up to 1500 m/z. Differential pulse voltammetry indicated that aged wines have lower antioxidant capacity than young wine (400 mV), but higher than malvidin-3-O-glucoside (483 mV). Tafel's plots showed that the electrochemical process occurring in aged wines is different from young wines. Six, seven and eight year old wines show similar behaviour with plots of 234, 177 and 188 mV/dec, respectively. These values are higher than the expected 120 mV/dec corresponding to a first electronic transfer but smaller compared to the 523 mV/dec corresponding to young wine

Determination of low molecular weight carbohydrates in Cabernet sauvignon red wines

Low molecular weight carbohydrates (LMW) were determined in a Chilean Cabernet Sauvignon red wine by the Dubois method, a specific method for the determination of carbohydrates. Dialysis treatment of red wine allowed the separation of pentoses, hexoses, reducing and non-reducing oligosaccharides and glycosides (LMW) from the polysaccharides fraction (HMW) fraction. The total sugar content of red wine by Dubois method was 5.55 g/L. The content of LMW sugars determined by Dubois method (3.63 g/L) is higher than the sugar content of the polysaccharides fraction (1.78 g/L). Analysis of twenty more samples of Cabernet Sauvignon red wines showed that the high molecular weight fraction content is quite iterative (mean value 2.50 g/L). The advantage of the Dubois method in relation to Fehling method is that the former does not need prior decolouration of the sample and there is not interference of aldehydes. The method developed in this work may be a complementary method for the determinatio

Chiroptical characterization of homopolymeric block fractions in alginates

Homopolymannuronic and homopolyguluronic fractions were obtained by partial hydrolysis of the alkaline extracts from the brown seaweeds Ascoseira mirabilis, Desmarestia menziessi, Desmarestia ligulata and Durvillaea sp. collected in southern Chile. Full characterization of the fractions was achieved by FT-IR and NMR spectroscopy. Total hydrolysis with 90% formic acid of the homopolymeric fractions allowed the preparation of mannuronic and guluronic acids. Both monomers and homopolymeric fractions as neutral salts were studied by CD and ORD. Chiroptical spectra were similar in shape and sign to those previously published in the literature, and permitted to assign D configuration to mannuronic acid and L configuration to guluronic acid in alginic acids. Specific optical rotation values at the sodium D light for the homopolymannuronic (∼-100°) and homopolyguluronic (∼-110°) acid fractions were obtained. These high negative values are proposed for the assignment of the absolute configuration of monomers in homopolymeric fractions.Fil: Martínez Gómez, Fabián. Universidad de Santiago de Chile; ChileFil: Mansilla, Andrés. Universidad de Magallanes; Chile. Instituto de Ecología y Biodiversidad; ChileFil: Matsuhiro, Betty. Universidad de Santiago de Chile; ChileFil: Matulewicz, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; ArgentinaFil: Troncoso Valenzuela, Marcos A.. Universidad de Concepción; Chil