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

Determinants and Tools to Evaluate the Ecological Sustainability of Using Forest Biomass as an Alternative Energy Source

Forest biomass, the most ancient of fuels, is again in the center of renewable energy production. This chapter provides an introductory view of the main factors that condition the ecological sustainability of this energy source. The basic concepts of ecological sustainability, ecological rotation, and ecological thresholds (among others) are presented. The state of the art on approaches to assess the sustainability of forest biomass production for heat and electricity is discussed, and tools available for decision-makers to evaluate the sustainability of forest biomass production and management are described. This chapter then describes the main advantages and drawbacks of forest certification, growth and yield tables, and ecological models in relationship to their use in sustainable forest management for biomass and energy production

The relation between segment disclosure and earnings quality

We investigate the relation between segment disclosure and earnings quality. Using a US sample for the period 2001-2006, we find a positive relation between earnings quality and the quantity of segment disclosures. We use lead-lag tests to examine the flow of causality, and our results show that current segment disclosure is positively related to prior levels of earnings quality, while current earnings quality scores are not related to prior levels of segment disclosure. Thus, the causality flows from earnings quality to segment disclosure. Our results hold for both business and geographic segment disclosure.We acknowledge financial assistance from the Spanish Ministry of Innovation and Science (ECO2010-19314, ECO2008-06238-C02-01/ECON, SEJ2007-67582-C02-02/ECON, ECO2009-10796 and Consolider Grant #2006/04046/002), the European Commission INTACCT Research Training Network (MRTN-CT-2006-035850), and the government of the autonomous Community of Madrid (Grant # 2008/00037/001)

Introductory Chapter: Land Use Change Ecosystem Services and Tropical Forests

Meteorology & climatolog

Segment disclosure and cost of capital

We investigate whether segment disclosure influences cost of capital. Improved segment reporting is expected to decrease cost of capital by reducing estimation risk. However, in a competitive environment segment disclosure may also generate uncertainties about future prospects and lead to a larger cost of capital. Asset-pricing tests confirm that segment disclosure is a priced risk factor. Also, segment disclosure reduces ex-ante estimates of cost of equity capital and other measures connected to risk. These results suggest a negative relation between segment disclosure and cost of capital. Our results also show that competition reduces, but does not eliminate, the previous relationship.We acknowledge financial assistance from the Spanish Ministry of Economy and Competitiveness (ECO2013-48328-C3-3-P, ECO2010-19314, ECO2009-10796 and, ECO2012-36559), the European Commission INTACCT Research Training Network (MRTN-CT-2006-035850), the Fundación Ramón Areces, and the government of the Autonomous Community of Madrid (Grant # 2008/00037/001)

Maintaining Ecosystem Function by Restoring Forest Biodiversity – Reviewing Decision-Support Tools that link Biology, Hydrology and Geochemistry

Not all forest models are applicable to a meta-modelling approach. Hence, the objective of the research presented here was to identify and compare the available forest models already being used in research, and to evaluate their suitability for use as decision-support tools in designing successful restoration plans to bring forest biodiversity and function back to sites disturbed by industrial activities (mining in particular).This work was conducted with funding generously supplied by Total E&P Canada Ltd., Calgary, Alberta, Canada

The Complementarity between segment disclosure and earnings quality, and its effect on cost of capital

We investigate the role of earnings quality in determining the levels of segment disclosure, and whether and how better quality earnings and segment disclosure influences cost of capital. Using a large US sample for the period 2001-2006, we find a positive relation between earnings quality and levels of segment disclosures. We also find that firms providing better quality segment information, contingent upon good earnings quality, enjoy lower cost of capital. We base our empirical tests on a self created index of segment disclosure. Our results contribute to a better understanding of (1) the incentives for providing segment disclosures, and (2) how accounting quality (quality of segment information and earnings quality) is related to the cost of capital

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