Consumo bacteriano heterotrófico sobre glucosa y glicolato en una laguna eutrófica (Chascomús, Argentina)

El presente trabajo se realizó en la Laguna de Chascomús (Prov. Bs, As., Argentina),cuerpo eutrófico, poco profundo, de gran productividad y capacidad biogenética. La metodología aplicada fue la propuesta por Wright & Hobbie (1965), efectuándose las correcciones por la tasa de expiración de CO2 (Hobbie & Crawford, 1969). Los parámetros cinéticos del consumo de glicolato muestran una marcada fluctuación estacional y con la productividad. Vmax y Kt + Sn se incrementaron durante el verano en superficie (12,8 µg.-1h-1 y 588 µg.l-1 respectivamente), y disminuyen en la muestra cercana al fondo en invierno, hasta valores no detectables con esta metodología. El Tt aumentó en agosto a 76 hs. Estos parámetros, para glucosa, no variaron ni estacional ni verticalmente tanto como los del glicolato; siendo sus valores máximos: 5,6 µg.l-1h-1 (Vmax); 49,5 µg.l-1 (Kt + Sn) y 57,27 hs. (Tt) durante enero-febrero de 1986. Las elevadas tasas de consumo, asimilación y excreción halladas durante la primavera y el verano, son producto de la presencia de una comunidad bacteriana heterotrófica adaptada a consumir los productos de excreción. El máximo porcentaje de mineralización observado, para él glicolato (85%) fue hallado en superficie durante enero de 1986; por el contrario el porcentaje de excreción de 14CO2 proveniente de la glucosa no superó el 36% en igual época del año, siendo por lo tanto su rendimiento mucho mayor.El presente trabajo se realizó en la Laguna de Chascomús (Prov. Bs, As., Argentina),cuerpo eutrófico, poco profundo, de gran productividad y capacidad biogenética. La metodología aplicada fue la propuesta por Wright & Hobbie (1965), efectuándose las correcciones por la tasa de expiración de CO2 (Hobbie & Crawford, 1969). Los parámetros cinéticos del consumo de glicolato muestran una marcada fluctuación estacional y con la productividad. Vmax y Kt + Sn se incrementaron durante el verano en superficie (12,8 µg.-1h-1 y 588 µg.l-1 respectivamente), y disminuyen en la muestra cercana al fondo en invierno, hasta valores no detectables con esta metodología. El Tt aumentó en agosto a 76 hs. Estos parámetros, para glucosa, no variaron ni estacional ni verticalmente tanto como los del glicolato; siendo sus valores máximos: 5,6 µg.l-1h-1 (Vmax); 49,5 µg.l-1 (Kt + Sn) y 57,27 hs. (Tt) durante enero-febrero de 1986. Las elevadas tasas de consumo, asimilación y excreción halladas durante la primavera y el verano, son producto de la presencia de una comunidad bacteriana heterotrófica adaptada a consumir los productos de excreción. El máximo porcentaje de mineralización observado, para él glicolato (85%) fue hallado en superficie durante enero de 1986; por el contrario el porcentaje de excreción de 14CO2 proveniente de la glucosa no superó el 36% en igual época del año, siendo por lo tanto su rendimiento mucho mayor

Sorption-desorption response for perylene uptake by wild yeasts isolated from polluted sediments

The industrial developments over the past few decades produced deliberately and/or accidentally released of xenobiotics to the environment, remaining these areas polluted for long periods. Bioremediation is a hard issue due to the complex mixture of the xenobiotics and to soil-sorbed contaminants that are not available for biotransformation. So microorganisms must be able to uptake the sorbed-molecules or facilitate the desorption by producing surfactants. The adsorption/desorption process was scarcely studied in fungi and sorbed-compounds fixed in diverse compartments with different desorption rates. Therefore, our aims were to isolate yeasts from polluted sediments, to evaluate the perylene bioavailability and to quantify their potential uptake. Pseudozyma rugulosa and Centrolene petrophilum grew on perylene cultures and their uptake were significant in relation to the other species. Different soils, type I, II and III, with diverse organic carbon, pH, cation exchange capacity, sand, silt and clay proportions were used. Soil type-III showed the higher perylene level in the aqueous phase and sorbed to particles, nevertheless showed the higher desorption rate. Perylene availability were in relation with the soil matrix and organic content, and the desorption coefficients were significantly related with the P. rugulosa and C. petrophilum kinetic parameters. These results were in relation to the biosurfactant production by both fungal species. Desorption parameters significantly fitted perylene uptake, with R2 = 0.97 for P. rugulosa and R2 = 0.95 for C. petrophilum. Biosurfactants and extracellular enzymes production explained the perylene degradation by both yeasts, being the results confirmed by the surface tension measurements.Fil: Romero, Maria Cristina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Microbiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Urrutia, M. I.. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; ArgentinaFil: Moreno Kiernan, A. M.. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; Argentin

Sorbed Anthracene Degradation by Sophorolipid Producing Yeasts

The organic pollutan adsorption/desorption process by microbial degradation had been less studied than metal ones. The sorption assays alone did not predict desorption, due to hysteresis, irreversibility, fixed compounds in different sites, with diverse desorption rates. Most of the studies dealt with bacteria rather than filamentous fungi and yeasts. So, our aims were to isolate yeasts from polluted sediments, to quantify its potential to uptake anthracene (An) and to evaluate the bioavailability by a desorption model. Yeasts were isolated from hydrocarbon-polluted samples, 40-isolates grew in anthracene-plates. Molecular characterization was achieved by sequence analysis of the ITS1-5.8S rRNA-ITS4 and 26S rRNA regions; morphological and physiological determination were also done. Candida parasilopsis, Pichia anomala and Rhodothorula mucilaginosa were the prevalent yeasts. An-degradation was assessed in soil-systems with 0, 50, 100, 150, 200 and 250 µg An/l, 3 differentes sorbens types, organic carbon, organic nitrogen, PAHs, sand:silt:clay, pH and cation exchange capacity. Sophorolipids excretion were confirmed by HPLC, UV-detector with active fraction at 9.669 min (RT 9.646 min = sophorolipid-standard). A desorption model with equilibrium, nonequilibrium and nondesorption areas, was applied to explain the experimental data, An-transformation was greater in the organic liquid-phase than in the soil-sorbed ones; the desorption-coefficients and soil components were negatively correlated with the kinetic parameters. The An-release depended on the sophorolipid excretion, soil matrix and particles sizes. Desorption parameters significantly fitted the yeast uptake, with R2 = 0.97, R2 = 0.90 and R2 = 0.97 for C. parasilopsis, P. anomala and R. mucilaginosa, respectively

Descripción del proteoma de bellota de la encina (Quercus ilex) mediante extracción secuencial de proteínas y análisis por LC-MS

Comunicaciones a congreso

Aproximaciones -ómicas al estudio de la germinación de semillas de especies recalcitrantes: el caso de la encina (Quercus ilex subsp. ballota)

La presente Tesis Doctoral está centrada en el estudio de la encina (Quercus ilex L. subsp. ballota [Desf.] Samp.), una especie dominante en los sistemas silvopastorales mediterráneos. El mantenimiento y la sostenibilidad de los bosques de encina se enfrenta actualmente con problemas y retos mayormente relacionados con la conservación de semillas viables, ya que se trata de una semilla recalcitrante, y con la alta tasa de mortalidad de los individuos adultos y plantones luego de ser trasplantados a campo, resultado de las adversas condiciones ambientales. En el presente trabajo se llevó a cabo el estudio de la germinación de semillas de encina, así como de plántulas en estadio temprano mediante una aproximación multidisciplinar que combina las técnicas clásicas de biología molecular con las “ómicas”. Con este objetivo general fueron propuestos los siguientes objetivos específicos 1. Realizar un análisis transcripcional de un grupo de genes candidatos implicados en tolerancia a la de desecación, regulación de la señalización de ABA, metabolismo y defensa contra el estrés oxidativo, a lo largo del proceso de germinación. 2. Identificar genes de expresión diferencial en semilla germinada y de plántulas muy jóvenes de Q. ilex mediante el uso de hibridación sustractiva por supresión (SSH). 3. Identificar proteínas cuya abundancia se ve alterada durante la germinación y desarrollo de plántulas en estadios tempranos, determinando los perfiles proteómicos mediante aproximaciones basadas y libres de gel. 4. Identificar el phosphoproteoma y los cambios que ocurren durante la germinación de semillas Los resultados del análisis transcripcional del grupo de genes candidatos revelaron que las semillas maduras de Q. ilex presentan algunas características fisiológicas intracelulares propias de las semillas ortodoxas que incluyen (i) acumulación de azúcares (sacarosa) y proteínas protectoras (DHN3) y (ii) acumulación de transcriptos implicados en la síntesis de oligosacáridos osmorreguladores de rafinosa (GolS) y en la defensa contra el estrés oxidativo (Sod1, Gst). Sin embargo, las semillas maduras de Q. ilex, como otras semillas recalcitrantes se dispersan con un alto contenido de agua y mantienen el metabolismo parcialmente activo. Los resultados de este análisis transcripcional fueron verificados y complementados con la determinación de (i) niveles de fitohormonas (ABA, GA3, GA4, IAA, iP and iPR), (ii) acumulación de azúcares (Sac, Glc, Fru) y (iii) determinación de proteínas mediante inmunodetección (DHN3, GAPDH, RBCL) y actividad enzimática (SOD); estos resultados mostraron una buena correlación con los transcriptos analizados. El análisis de expresión diferencial de genes mediante SSH permitió identificar por primera vez en Q. ilex un grupo de ESTs correspondiente a genes diferencialmente expresados en semillas germinadas y plántulas en desarrollo temprano. En las semillas germinadas se identificaron 31 genes sobre-expresados, entre los que se incluyen genes que codifican para proteínas implicadas en la respuesta a estreses, transporte, defensa contra estrés oxidativo, modificación de la pared celular, ciclo celular, metabolismo de proteínas y transducción. Por otro lado, 39 transcriptos no redundantes se encontraron sobre-expresados en estadio temprano de plántulas. Las proteínas codificadas por estos transcritos fueron agrupadas en siete categorías funcionales que incluyen fotosíntesis, metabolismo secundario, transporte, señalización, respuesta a diversos estreses, expresión génica y organización de componentes...This work is focused on holm oak (Quercus ilex L. subsp. ballota [Desf.] Samp.) a dominant tree species in natural forest ecosystems over large areas of the Western Mediterranean Basin. Q. ilex forest maintenance and sustainability are facing important problems and challenges related to seed viability/conservation, and plant mortality in both adult trees and young oneyear- old plants after field transplantation resulting from adverse environmental conditions such as drought and the so-called decline syndrome. In the present Doctoral Thesis, the germination and seedling growth of Q. ilex was studied applying a multidisciplinary “omics” approach combined with classical biochemical approaches, according to the actual trends in biosciences research. Within this general aim, specific objectives pursued in this thesis were: 1. Determine the expression profile of a selected group of protein coding genes involved in desiccation tolerance, regulation of ABA-signalling, metabolism and antioxidative defence. 2. Identify differentially expressed genes between germinated seeds and seedlings of Q. ilex by using a suppression subtractive hybridization (SSH). 3. Analyse changes in the proteomic profiles during germination and seedling growth through gel based and gel free approaches. 4. Analyse the dynamic protein phosphorylation changes during seed germination and seedling development. The transcriptional analysis revealed that mature Q. ilex seeds show some of the intracellular physiological characteristics of orthodox seed that included (i) accumulation of non-reducing carbohydrates (sucrose) and protective proteins (DHN3) and (ii) accumulation of transcripts involved in the synthesis of certain osmoregulator of raffinose series oligosaccharides (GolS), the anti-oxidative defence (Sod1, Gst). But the holm oak mature acorns, like other recalcitrant seeds, have the ability to maintain a partially active metabolism. The transcriptional analysis results were verified and complemented with the determination of (i) plant hormones levels (ABA; the gibberellins GA3 y GA4; the auxin IAA and the cytokinins iP and iPR,) (ii) sugars accumulation (Suc, Glc, Fru) and (iii) proteins amounts determined by immunoblotting (DHN3, GAPDH, RBCL) and/or enzymatic activity (SOD) and good correlation was found whit transcript levels. The analysis of differentially expressed genes by SSH allowed the identification for the first time a large number of putative differentially expressed ESTs from the embryo axis in germinated seeds and from shoot seedlings of Q. ilex during the postgermination and seedling establishment. Thirty-one over-expressed genes were identified in germinated seeds at the germination stage. Proteins encoded by these genes are representative of eight functional categories: stress responses, transport, oxidation-reduction, cell wall modification, cell division cycle, protein metabolism, cellular component organization and translation. On the other hand, 39 non-redundant transcripts over-represented in Q. ilex shoots seedlings were grouped in seven functional categories: photosynthesis, secondary metabolism, transport, signalling, stress response, gene expression and cellular component organization. These data constitute an important genomics resource that should clearly benefit further germination and other biological process research on Q. ilex..

Improvement of fatty acid profile and studio of rheological and technological characteristics in breads supplemented with flaxseed, soybean, and wheat bran flours

Functional breads constitute an interesting alternative as vehicle of new essential fatty acids sources. The aim of this study was to improve the fatty acids (FA) profile of bakery products, producing breads with low saturated fatty acid (SFA) content and with high polyunsaturated fatty acid (PUFA) content, through partial substitution of wheat flour by other ingredients (soy flour, flax flour, and wheat bran) and to analyze the effect of this change on the technological, rheological, and sensorial characteristics of breads. Flaxseed flour (FF), soybeans flour (SF), or wheat bran (WB) was used to replace 50, 100, and 150 g kg-1 of wheat flour (WF) in breads. FF or SF produced a decrease in monounsaturated and SFA and an increase of PUFA in these breads. Furthermore, breads replaced with FF presented considerable increase in the content of n3 FA, while, SF or WB contributed to rise of linoleic and oleic FA, respectively. The substitution percentage increase of FF, SF, or WB to formulation produced changes in the colour, rheological, textural, and technological characteristics of breads. This replacement resulted in improved lipid profile, being breads with 50 g kg-1 SF, the better acceptance, baking features, and enhanced fatty acid profile.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Improvement of fatty acid profile and studio of rheological and technological characteristics in breads supplemented with flaxseed, soybean, and wheat bran flours

Functional breads constitute an interesting alternative as vehicle of new essential fatty acids sources. The aim of this study was to improve the fatty acids (FA) profile of bakery products, producing breads with low saturated fatty acid (SFA) content and with high polyunsaturated fatty acid (PUFA) content, through partial substitution of wheat flour by other ingredients (soy flour, flax flour, and wheat bran) and to analyze the effect of this change on the technological, rheological, and sensorial characteristics of breads. Flaxseed flour (FF), soybeans flour (SF), or wheat bran (WB) was used to replace 50, 100, and 150 g kg-1 of wheat flour (WF) in breads. FF or SF produced a decrease in monounsaturated and SFA and an increase of PUFA in these breads. Furthermore, breads replaced with FF presented considerable increase in the content of n3 FA, while, SF or WB contributed to rise of linoleic and oleic FA, respectively. The substitution percentage increase of FF, SF, or WB to formulation produced changes in the colour, rheological, textural, and technological characteristics of breads. This replacement resulted in improved lipid profile, being breads with 50 g kg-1 SF, the better acceptance, baking features, and enhanced fatty acid profile.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Fricke and polymer gel 2D dosimetry validation using Monte Carlo simulation

Complexity in modern radiotherapy treatments demands advanced dosimetry systems for quality control. These systems must have several characteristics, such as high spatial resolution, tissue equivalence, three-dimensional resolution, and dose-integrating capabilities. In this scenario, gel dosimetry has proved to be a very promising option for quality assurance. In this study, the feasibility of Fricke and polymer gel dosimeters suitably shaped in form of thin layers and optically analyzed by visible light transmission imaging has been investigated for quality assurance in external radiotherapy. Dosimeter irradiation was carried out with a 6-MV photon beam (CLINAC 600C). The analysis of the irradiated dosimeters was done using two-dimensional optical transmission images. These dosimeters were compared with a treatment plan system using Monte Carlo simulations as a reference by means of a gamma test with parameters of 1 mm and 2%. Results show very good agreement between the different dosimetric systems: in the worst-case scenario, 98% of the analyzed points meet the test quality requirements. Therefore, gel dosimetry may be considered as a potential tool for the validation of other dosimetric systems.Fil: Vedelago, José Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Chacón Obando, D.. Universidad Nacional. Physics Department; Costa Rica. Universidad Nacional de Córdoba; ArgentinaFil: Malano, Francisco Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Conejeros, R.. Servicio de Radioterapia, Icos. Temuco, Chile;Fil: Figueroa, R.. Universidad de la Frontera; ChileFil: Garcia, D.. Servicio de Imagenes por Resonancia Magnética; ChileFil: González, G.. Servicio de Imagenes por Resonancia Magnética; ChileFil: Romero, Marcelo Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Santibañez, M.. Servicio de Imagenes por Resonancia Magnética; ChileFil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Velásquez, J.. Servicio de Radioterapia; ChileFil: Mattea, Facundo. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Valente, M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad de La Frontera. Departamento de Ciencias Físicas; Chil

Application of Chelating Agents to Enhance Fenton Process in Soil Remediation: A Review

Persistent organic contaminants affecting soil and groundwater pose a significant threat to ecosystems and human health. Fenton oxidation is an efficient treatment for removing these pollutants in the aqueous phase at acidic pH. However, the in-situ application of this technology for soil remediation (where pHs around neutrality are required) presents important limitations, such as catalyst (iron) availability and oxidant (H2O2) stability. The addition of chelating agents (CAs), forming complexes with Fe and enabling Fenton reactions under these conditions, so-called chelate-modified Fenton process (MF), tries to overcome the challenges identified in conventional Fenton. Despite the growing interest in this technology, there is not yet a critical review compiling the information needed for its real application. The advantages and drawbacks of MF must be clarified, and the recent achievements should be shared with the scientific community. This review provides a general overview of the application of CAs to enhance the Fenton process for the remediation of soils polluted with the most common organic contaminants, especially for a deep understanding of the activation mechanisms and influential factors. The existing shortcomings and research needs have been highlighted. Finally, future research perspectives on the use of CAs in MF and recommendations have been provided.Depto. de Ingeniería Química y de MaterialesFac. de Ciencias QuímicasTRUEComunidad de MadridMinisterio de Cienciapu

Assessment of fruit quality of grapefruit at postharvest influenced by reclaimed water and deficit irrigation

[SPA] El objetivo de la investigación fue evaluar los efectos a largo plazo del riego con agua regenerada (AR) y agua del trasvase (AT) y diferentes estrategias de riego (control, C, y riego deficitario controlado, RDC) sobre la calidad de pomelos durante su almacenamiento en frío. Los resultados mostraron que el riego con AR y, principalmente, el RDC incrementaron la cantidad de solidos solubles, mejorando así el índice de madurez. Sin embargo, el AR combinada con RDC disminuyó el nº de frutos de la categoría de mayor tamaño al final del almacenaje y AT-RDC presentó el menor contenido en zumo. [ENG] The aim of our research was to discover the effects of the long-term irrigation with saline reclaimed (RW) and transfer (TW) water and different irrigation strategies: control (C) and regulated deficit irrigation (RDI) on fruit quality of grapefruit during cold storage. Result showed sugar/acid ratio was mainly increased by RDI, but also by RW, due to an important increase in soluble solid content. However, RDI combined with RW, significantly decreased the number of fruits in the largest category 5 at the end of cold storage and TW-RDI showed lower values of juice content.This study was supported by two CICYT projects (AGL2010-17553 and AGL2013-49047-C2- 515 2-R) projects and SENECA–Excelencia Científica (19903/GERM/15)