Down-regulation of a pectin acetylesterase gene modifies strawberry fruit cell wall pectin stracture and increases fruit firmness

Antisense-mediated down-regulation of several fruit-specific genes has previously demonstrated how the cell wall disassembly in strawberry fruit is mediated by a series of enzymes that act sequentially (Posé et al. 2011). An interesting example, the silencing of the polygalacturonase gene FaPG1, was also related with a significant increase of the post-harvest strawberry fruit firmness (Posé et al. 2013). Our research group has isolated a pectin acetylesterase gene, FaPAE1, which expression is enhanced during strawberry ripening. The main goal of this work was to elucidate the role of the degree of acetylation in cell wall integrity and fruit firmness through the antisense-mediated down-regulation of FaPAE1 in strawberry plants. Several transgenics lines were generated and 5 of them produced fruits 5-15% firmer than controls. Cell wall from ripe fruits was isolated from two independent transgenic lines and a control line, and sequentially extracted with different solvents (PAW, H2O, CDTA, Na2CO3). Modifications in fraction yield, its sugar composition and the degree of acetylation in each fraction were determined. Higher amounts of CDTA and Na2CO3 fractions were obtained in transgenic fruits, suggesting a decreased pectin solubilization as results of FaPAE1 silencing. Accordingly, the degree of acetylation of the Na2CO3-soluble pectins was greater in the transgenic lines than the control, but the opposite result was found in pectins from the CDTA fraction. These results suggest that PAE is preferentially active in pectis that are tightly bound to the cellulose-hemicellulose network and its activity could reduce the complexity of the cell wall structure, allowing that other hydrolytic enzymes could access the pectin chains. Thus, the increased fruit firmness observed in the transgenic FaPAE1 lines could be attributed to the direct effect of the silencing of the PAE enzyme and also to the indirect effect that the increase of the degree of acetylation of pectins has on the activity of other enzymes involved in the cell wall degradation. * Posé et al. (2011). Genes, Genomes and Genomics, 5 (Special Issue 1):40-48 * Posé et al. (2013). Plant Physiology, 150: 1022-1032 We acknowledge support from the Spanish Ministry of Economy and competitivity and Feder EU Funds (grant reference AGL2011-24814), FPI fellowships support for SP (BES-2006-13626) and CP (BES-2009027985), and grant "Ramón y Cajal" support for AJMA (RYC-2011-08839).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Rhamnogalacturonase lyase gene downregulation in strawberry and its potential on mechanical fruit properties

Strawberry softening is one of the main factors that reduces fruit quality and leads to economically important losses. Textural changes during fruit ripening are mainly due to the dissolution of middle lamellae, a reduction in cell-to-cell adhesion and the weakening of parenchyma cell walls as a result of the action of cell wall modifying enzymes. Functional studies of genes encoding pectinase enzymes (polygalacturonase, pectate lyase and -galactosidase) support a key role of pectin disassembly in strawberry softening. Evidence that RG-I may play an important role in strawberry texture has been obtained from the transient silencing of a RG-lyase gene. Pectins are major components of fruit cell walls and highly dynamic polysaccharides, but due to their heterogeneity the precise relation between the structures and functions is incomplete. In this work, stable transgenic strawberry lines with a rhamnogalacturonate lyase gene (FaRGLyase1) down-regulated have been analyzed. Several transgenic lines showing more than 95% silencing of FaRGLyase1 displayed fruit firmness values higher than control. Cell walls from these lines were extracted and analyzed by ELISA and Epitope Detection Chromatography (EDC). This last technique is based on the detection of specific cell wall oligosaccharide epitopes and provides information on sub-populations of pectins containing homogalacturonan and RG-I domains, but also reveals potential links with other cell wall polysaccharides such as xyloglucan. The results obtained indicate that the silencing of FaRGLyase1 reduces degradation of RG-I backbones, but also homogalacturonan, in cell walls, especially in pectin fractions covalently bound to the cell wall. These changes contribute to the increased firmness of transgenic fruits.This research was supported by FEDER EU Funds and the Ministerio de Economía y Competitividad of Spain (grant reference AGL2014-55784-C2), a Marie Curie IEF within the 7th European Community Framework Programme (reference: PIEF-2013-625270) for SP and a FPI fellowship (BES-2015-073616) to support PR-V. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

El aceite de oliva en alimentos para untar

Chemical hydrogenation of unsaturated fatty acids is a commonly applied reaction to food industries. The process may imply the movement of double bonds in their positions on the fatty acid carbon chain, producing positional and geometrical isomers ( trans fatty acids). Through hydrogenation, unsaturated oils are converted to margarines and vegetable shortenings. The presence of trans fatty acids in foods is undesirable, as trans fatty acids raise the plasma levels of total and low-density lipoproteins (LDL), while decrease the plasma level of high-density lipoproteins (HDL), among other effects. The use of olive oil to prepare fat spread opens new insights into the commercial development of healthy novel foods with a positive image in terms of consumer appeal.La hidrogenación química de los ácidos grasos insaturados es una reacción que se utiliza con frecuencia en la industria alimentaria. El proceso implica el movimiento de los dobles enlaces en la cadena hidrocarbonada de los ácidos grasos, y la aparición de isómeros posicionales y geométricos (ácidos grasos trans ). La ingesta inadecuada de alimentos que pueden contener cantidades significativas de ácidos grasos trans se asocia con el aumento en sangre de colesterol total y LDL, y la disminución de HDL, entre otros efectos. Por lo tanto, el uso de aceite de oliva en la preparación de grasas para untar constituye un importante avance en el desarrollo comercial de nuevos alimentos saludables con una imagen positiva para el consumidor

Análisis de la erosión mediante modelado e indicadores visuales en la microcuenca batatal, Rio Guapi-Macacu, Rio de Janeiro, Brasil.

A erosão e um fenômeno geológico natural que cada vez e mais forte devido á mudança do uso do solo e ao pouco conhecimento das praticas de conservação do solo. As atuais abordagens top-down do zoneamento do uso do solo na academia e nas políticas não são entendidos e adotados facilmente por os produtores. A equação universal de perdida do solo (USLE) e muito utilizada pra a modelagem da erosão regionalmente. Contudo, a escala local podem se apresentar diferentes condições que não correspondem com as predições do modelo. A Microbacia Batatal (Rio de Janeiro, Brasil) tem um relevo muito inclinado e intensas chuvas que levam de forma natural a uma erosão considerável. Por isso e importante incentivar a conservação do solo na escala local pra prevenir os perniciosos efeitos da erosão. Neste estudo a perdida de solo nesta microbacia foi analisada por meio da USLE, dos indicadores visuais dentro do terreno, e entrevistas aos produtores. Isso foi feito pra comparar as diferentes aproximações usando as matrizes de confusão e pra entender os motivos por os quais os produtores empregam suas atuais praticas de produção. As vantagens e desvantagens das diferentes aproximações a perdida do solo nos terrenos estabeleceram-se e observo-se que os produtores detectam facilmente muitos dos indicadores visuais utilizados neste estudo, embora eles não relacionam os indicadores visuais com a erosão. As aproximações utilizadas podem se aplicar complementarmente pra entender melhor as relações políticas, sociais, econômicas e ecológicas relacionadas com o manejo do solo na microbacia. Também podem ser melhorados para elaborar programas apropriados de assistência sinérgica aos produtores na proteção do solo. E necessário fazer um processo comunitário para a sensibilização da população sobre a erosão e um acompanhamento nos processos da conservação do solo.Thesis (Maestría en Ciencias Ambientales) - Universidad Autónoma de San Luis Potosí, México. Orientadores: Carlos Alfonso Muñoz Robles, PMPCA; Elaine Cristina Cardoso Fidalgo, CNPS

Implementacion y análisis de métodos numéricos basados en flujo potencial con aplicación en turbomáquinas

Este artículo aborda la resolución de flujos no viscosos y en particular su aplicación al estudio de cascada de álabes. Para ello se analizarán modelos de flujo potencial resolviendo la ecuación de Laplace mediante diferentes variaciones del método de los Paneles. Se ha realizado una validación de los resultados obtenidos para perfiles aislados con valores experimentales obtenidos por la NACA. Además, se ha realizado un estudio comparativo entre los distintos resultados obtenidos con los diferentes métodos de los paneles implementados(Source, Vortex y Source-Vortex). Una vez comprobada la bondad de los distintas variantes del método de los paneles para perfiles aislados se ha ampliado el método a cascadas de álabes y se ha realizado también una validación con valores experimentales obtenidos de la bibliografía.In this work an analysis of different panel methods applied to turbomachinery has been presented, within the conditions of potential flow as well its behaviour with different shapes and its advantadges and inconvenients applied to aerodynamics profiles. Finally one of these methods have been extended and corrected to the analysis of compressor cascade

Efecto del silenciamiento de genes que codifican poligalacturonasas sobre el reblandecimiento del fruto de fresa asociado a la maduración

La degradación de las pectinas de la pared celular mediada por poligalacturonasas juega un papel clave en el reblandecimiento de la fresa. Así, el silenciamiento del gen FaPG1 incrementa la firmeza del fruto maduro y alarga su vida postcosecha. Además de FaPG1, en fresa se ha descrito otro gen que codifica una poligalacturonasa específica de maduración, FaPG2. Con el fin de profundizar en el papel de estos genes, se han obtenido plantas transgénicas con el gen FaPG2 silenciado (líneas BPG), así como plantas con FaPG1 y FaPG2 silenciados (líneas ABPG), obtenidas mediante retransformación de una línea antiFaPG1 (APG29) que mostraba un fuerte silenciamiento del gen y un incremento en la firmeza de fruto. Se obtuvieron 24 líneas BPG y 15 ABPG. Estas plantas, junto con la línea APG29 y controles sin transformar, fueron analizadas durante 3 años consecutivos. El 50% de las líneas BPG mostraron mayor firmeza de fruto rojo que el control sin transformar, aunque el incremento en firmeza fue similar al obtenido en la línea APG29. Todas las líneas dobles transformantes dieron frutos de mayor firmeza que el control, siendo los valores ligeramente superiores a los de la línea APG29 en alguna de ellas. A nivel de expresión, las líneas BPG seleccionadas mostraron un silenciamiento del gen FaPG2 que varió entre el 60-70%, e inesperadamente, un silenciamiento significativo de FaPG1, a pesar de la baja homología entre ambos genes. El silenciamiento de FaPG1 en las líneas ABPG fue superior al 95%; sin embargo, el silenciamiento de FaPG2 fue similar al obtenido en las plantas BPG. Estos resultados confirman el papel clave de las poligalacturonasas en el reblandecimiento de la fresa y sugieren la existencia de una regulación compleja en la expresión de ambos genes. Este trabajo ha sido financiado por el proyecto AGL2011-24814 y Fondos FEDERUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Experimental Characterization of the Dimensionless Momentum Length for Submerged Jet Discharges of Air-Steam Mixtures into Stagnant Water

[EN] A very efficient method of condensing the steam in various industrial applications is the steam direct discharge into pools with subcooled water. This kind of condensation is known as Direct Contact Condensation (DCC), by providing high heat transfer and mass exchange capacity, the steam condenses quickly. In the past few decades, many experiments have been carried out on the submerged jets of non-condensable gases and pure steam in pools, supplying much information of interest, but efforts are still being made to obtain more information. In particular, the research of steam and non-condensable gas mixtures is of great interest to the chemical, energy, and nuclear industry. Consequently, this study investigates the discharge behavior of air-steam mixtures in a pool with subcooled water by direct visualization techniques using a high-speed camera. To know the behavior of the dimensionless momentum length, tests were carried out considering several initial discharge conditions such as nozzle diameter, percentage of mixture, and flow rates. After image acquisition, a series of complex processing, filtering, and post-processing procedures are applied using a subroutine in MATLAB. The momentum length of the jet was measured and found to be heavily influenced by the nozzle diameter, the jet velocity, and the mixture percentage. A correlation is obtained for the dimensionless momentum length of the horizontal jet that depends on the Froude and Mach numbers.The authors would like to acknowledge the support provided through the Spanish project EXMOTRANSIN ENE2016-79489-C2-1-P and the Santiago Grisolía Program for the training of research personnel.Y. Córdova; D. Blanco; C. Berna; J. L. Muñoz-Cobo; A. Escrivá; Rivera-Durán, Y. (2022). Experimental Characterization of the Dimensionless Momentum Length for Submerged Jet Discharges of Air-Steam Mixtures into Stagnant Water. International Journal of Computational Methods and Experimental Measurements. 10(3):195-210. https://doi.org/10.2495/CMEM-V10-N3-195-21019521010