Aislamiento de cepas de traustoquitridios en la zona costera de Puerto Montt, Chile y evaluación de la producción de ácido docosahexaenoico (C22:6n-3, DHA)

Cuarenta y seis cepas que presentaron las característicasmorfológicas descritas para traustoquitridios fueron aisladasdesde muestras colectadas en cinco localidades de la zona costera de Puerto Montt, Chile, utilizando la técnica de polen de pino. Las 16 cepas que mostraron el perfil característico de tres bandas cuando el ADN fue amplificado con un conjunto de tres cebadores (FA1RA1, FA2RA2 y FA3RA3) diseñados para estos microorganismos(17), fueron cultivadas en medio líquido para evaluar la producción de ácido docosahexaenoico (C22:6n-3, DHA). El cultivo se realizó en matraces de Erlenmeyer agitados y la composición del medio basal fue: glucosa 10 g/L, extracto de levadura 4 g/L, en agua de mar diluida al 70%. Sólo 6 cepasprodujeron lípidos en los que se detectó DHA; los mayorescontenidos de DHA en los ácidos grasos totales y de DHA en la biomasa fueron 46,4% (cepa G4) y 36,2 mg/g (cepa M12-X1), respectivamente. El análisis de filogenia molecular basado en el alineamiento de la secuencia del gen que codifica para el ARN de la subunidad pequeña ribosomal (18S rRNA) confirmó que las tres cepas nativas que producen DHA pertenecen al phylum Labyrinthulomycota. Pruebas preliminares demostraron que es posible incrementar la concentración de biomasa (83%), el contenido de DHA en la biomasa (153%) y la concentración de DHA (71%) a través de la inclusión de glutamato monosódico en el medio de cultivo basal.

Efecto de un fertilizante a base de cúrcuma sobre la producción de tomate en invernadero

Inorganic fertilizers have impacts on the availability of nutrients and the content of organic matter in the soil, as well as on its native microbiota. A turmeric fertilizer (TF) with added food residues and wood ashes was developed to evaluate its effects on tomato production and crop soil properties. The TF was prepared by emulsion technology using three turmeric concentrations expressed as 1.0, 2.5 and 3.0 % w/v; it was characterized according to its rheological (apparent viscosity, consistency and flow behavior indexes) and physical (z-average droplet size) characteristics. Nitrogen, phosphorus and potassium (NPK) levels and moisture-holding capacity were measured in crop soil. Colour, soluble solid content, acidity, diameter and the number of tomatoes were evaluated. The photosynthetic index of the leaves of tomato plants was determined. It was observed that when turmeric concentration increased (> 1.0 % w/v), the droplet size decreased enhancing the physical stability of TF. NPK levels and moisture-holding capacity of the soil improved, especially with turmeric concentrations > 1.0% w/v. Positive effects on the tomato fruit properties (soluble solid content, acidity, diameter and tomato number) and photosynthetic index of tomato plant leaves were observed with turmeric concentrations of 2.5 and 3.0 % w/v. The TF positively influenced the crop soil and the metabolic process of the tomato plants, and the characteristics of its fruits.Los fertilizantes inorgánicos afectan la disponibilidad de nutrientes, el contenido de materia orgánica en el suelo y su microbiota nativa. En este trabajo se desarrolló un fertilizante de cúrcuma (TF) adicionado con residuos alimenticios y cenizas de madera, para evaluar sus efectos sobre la producción de tomate y propiedades del suelo. El TF se preparó mediante tecnología de emulsión utilizando tres concentraciones de cúrcuma (1.0, 2.5 y 3.0 % p/v), y se midieron sus características reológicas (viscosidad aparente, e índices de consistencia y comportamiento de flujo) y físicas (tamaño de gota z-average). Se midieron los niveles de nitrógeno, fósforo y potasio (NPK), y la capacidad de retención de humedad en el suelo. Se evaluaron el color, contenido de sólidos solubles, acidez, diámetro y número de tomates. Se determinó el índice fotosintético en las hojas de la planta. Se observó a medida que aumentaba la concentración de cúrcuma (> 1,0 % p/v), una disminución del tamaño de las gotas, mejorando la estabilidad física del TF. Los niveles de NPK y la capacidad de retención de humedad del suelo mejoraron, especialmente, con concentraciones de cúrcuma > 1,0 % p/v. Se observaron efectos positivos sobre los tomates (contenido de sólidos solubles, acidez, diámetro y número de unidades) y en el índice fotosintético de las hojas de la planta con concentraciones de cúrcuma de 2,5 y 3,0 % p/v. El TF influyó positivamente sobre el suelo y el proceso metabólico de las plantas, así como en las características de sus frutos

Extension of the selection of protein chromatography and the rate model to affinity chromatographyy

Artículo de publicación ISIThe rational selection of optimal protein purification sequences, as well as mathematical models that simulate and allow optimization of chromatographic protein purification processes have been developed for purification procedures such as ion-exchange, hydrophobic interaction and gel filtration chromatography. This paper investigates the extension of such analysis to affinity chromatography both in the selection of chromatographic processes and in the use of the rate model for mathematical modelling and simulation. Two affinity systems were used: Blue Sepharose and Protein A. The extension of the theory developed previously for ion-exchange and HIC chromatography to affinity separations is analyzed in this paper. For the selection of operations two algorithms are used. In the first, the value of h, which corresponds to the efficiency (resolution) of the actual chromatography and, S, which determines the amount of a particular contaminant eliminated after each separation step, which determines the purity, have to be determined. It was found that the value of both these parameters is not generic for affinity separations but will depend on the type of affinity system used and will have to be determined on a case by case basis. With Blue Sepharose a salt gradient was used and with Protein A, a pH gradient. Parameters were determined with individual proteins and simulations of the protein mixtures were done. This approach allows investigation of chromatographic protein purification in a holistic manner that includes ion-exchange, HIC, gel filtration and affinity separations for the first time

Lithium Tetraborate as a Neutron Scintillation Detector: A Review

The electronic structure and translucent nature of lithium tetraborate (Li2B4O7) render it promising as a scintillator medium for neutron detection applications. The inherently large neutron capture cross-section due to 10B and 6Li isotopes and the ease with which Li2B4O7 can be enriched with these isotopes, combined with the facile inclusion of rare earth dopants (occupying the Li+ sites), are expected to improve the luminescent properties, as well as the neutron detection efficiency, of Li2B4O7. The electronic structure of both doped and undoped Li2B4O7 were explored, using photoemission and inverse photoemission spectroscopies, optical measurements, and theoretical computational studies such as density functional theory. The scintillation properties are further enhanced because of the wide bandgap, makingLi2B4O7 extremely translucent, so that capturing the neutron scintillation output is neither hindered nor diminished. Therefore, in this review, demonstrations of the possible amplification of neutron capture efficiencies, courtesy of rare-earth dopants, along with insights into a significantly large charge production (associated with neutron capture), are presented

Measurements of the mass and width of the eta_c using psi' -> gamma eta_c

The mass and width of the lowest lying S-wave spin singlet charmonium state, the eta_c, are measured using a data sample of 1.06x10^8 psi' decays collected with the BESIII detector at the BEPCII storage ring. We use a model that incorporates interference between the signal reaction, psi' -> gamma eta_c, and a non-resonant radiative background to successfully describe the line shape of the eta_c. We measure the eta_c mass to be 2984.3 +- 0.6 +- 0.6 MeV/c^2 and the total width to be 32.0 +- 1.2 +- 1.0 MeV, where the first errors are statistical and the second are systematic.Comment: 7 pages, 1 figure, 1 table, matches Phys. Rev. Lett. versio