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

Fenotipo de los linfocitos intraepiteliales en el duodeno humano

La enfermedad celíaca (EC) es una patología autoinmune que se produce por la intolerancia permanente a las proteínas del gluten de la dieta. Cursa con una atrofia de la mucosa del intestino delgado y como consecuencia con una malabsorción de nutrientes. El diagnóstico es complejo debido a las diferentes presentaciones de la EC. El linfograma epitelial se utiliza para el diagnóstico, ya que ayuda a la evaluación del porcentaje de linfocitos intraepiteliales ( LIE) en concreto de la ratio de la subpoblación Tγδ + y NK-like, a través de citometría de flujo. En nuestro trabajo, hemos hecho una comparativa entre distintos grupos de estudio, determinando distintas subpoblaciones de LIE, potencialmente responsables de este trastorno, así como la expresión de algunos receptores especialmente en los grupos de estudio de EC activa y EC en tratamiento.Departamento de Pediatría e Inmunología, Obstetricia y Ginecología, Nutrición y Bromatología, Psiquiatría e Historia de la CienciaMáster en Investigación Biomédic

Síndrome de Landau- Kleffner (SLK): revisión sistemática

El presenteTrabajo de Fin de Grado (TFG) del Grado en Logopedia de la Universidad de Valladolid aborda el Síndrome de Landau-Kleffner(SLK)y su sintomatología mediante una revisión sistemáticadesde el prisma de la logopedia.El SLK se desarrollaen niñosentre los 18 meses y 13 añossin alteraciones del lenguaje previasyestá caracterizado por alteraciones en el trazado electroencefalográficoy afasia adquirida, estos síntomas están acompañados habitualmente porcrisis epilépticas y alteracionesde conducta.El objetivo último de este trabajo es conocer en profundidad esta patología y las alteraciones logopédicas que origina y que son objetivo de rehabilitación del lenguaje.Este TFG se inicia con una introducción formada por la justificación y el planteamiento del problema, la relación con las competencias del gradoyla exposición de los objetivos e hipótesis marcados en su elaboración. Posteriormente, se planteael marco teórico delSLK, continuado por la exposición del método utilizadoy el análisis de los artículos. Después, se muestranlos resultados obtenidos, la discusión, las limitaciones, la propuesta de líneas de investigación futurasy las conclusiones alcanzadastras su realización.Finalmente, se muestran las referencias de los artículos, documentos y fuentes de informaciónmanejadaspara realizar el presente trabajo.Grado en Logopedi

Influencia de los galactooligosacáridos sobre la biodisponibilidad y fermentación colónica de esteroles

El enriquecimiento de alimentos con esteroles vegetales (EV) es una práctica común en el desarrollo de alimentos funcionales orientados a reducir el riesgo de enfermedades cardiovasculares debido a su conocido efecto hipocolesterolemiante. Las bebidas a base de zumo de frutas y leche son una matriz idónea para el enriquecimiento con estos compuestos bioactivos debido a su perfil nutricional saludable. Además, su efectividad se ha demostrado en poblaciones diana como mujeres postmenopáusicas con hipercolesterolemia moderada (población de interés al presentar un mayor riesgo de enfermedad cardiovascular). La adición de galactooligosacáridos (GOS) a estas bebidas podría mejorar su funcionalidad debido al efecto beneficioso que presentan sobre la microbiota intestinal, estimulando de manera selectiva el crecimiento de Bifidobacterium y/o Lactobacillus spp., así como potenciar el efecto hipocolesterolemiante. Sin embargo, la adición de fibra podría reducir la bioaccesibilidad de los esteroles y modular su metabolismo colónico. El objetivo general de la presente Tesis Doctoral es evaluar el efecto de los GOS sobre la biodisponibilidad y fermentación colónica de los esteroles en bebidas a base de zumo de frutas y leche enriquecidas con EV mediante ensayos in vitro e in vivo. El contenido y bioaccesibilidad de los productos de oxidación de esteroles determinados en una bebida enriquecida con EV (2 g/250 mL) no se modifican durante el almacenamiento (20-25ºC, 6 meses). Además, el porcentaje de oxidación de los esteroles es bajo: 0,03 % para el β-sitosterol y 1,2 % para el colesterol. Los resultados obtenidos tras una digestión gastrointestinal micelar simulada indican que la adición de GOS (2,3 o 4,5 g/250 mL) a bebidas enriquecidas con EV (2,5 g/250 mL) no afecta a la bioaccesibilidad del colesterol (78-88%) ni a la de los EV totales (~37%). Este ensayo permite seleccionar la bebida con mayor contenido de GOS para posteriores estudios de fermentación colónica (in vitro e in vivo) y biodisponibilidad (in vivo). Por otro lado, la aplicación del método de digestión gastrointestinal Infogest a la bebida enriquecida con EV sin adición de GOS no permite la cuantificación del colesterol en la fracción bioaccesible correspondiente. Se demuestra así la necesidad de adaptar el método a la determinación de la bioaccesibilidad de esteroles y se propone el cambio de origen de las sales biliares utilizadas (bovinas en lugar de porcinas) o la reducción de su concentración (de 10 mM a 1,4 mM). Además, se observa que la presencia de GOS en la bebida enriquecida con EV favorece la metabolización de los esteroles evaluada mediante un sistema in vitro dinámico multicompartimental. Se demuestra que la formación de metabolitos de los esteroles (coprostanol, etilcoprostanol y metilcoprostanol) es dependiente del tramo colónico, ya que solo tiene lugar en los reactores del colon transversal y descendente. De la misma manera, la producción de ácidos orgánicos durante la fermentación colónica de las bebidas es mayor en estos reactores y se potencia en presencia del prebiótico. La mayor actividad metabólica observada en los tramos del colon transversal y descendente con respecto al colon ascendente coincide con una mayor riqueza y diversidad de especies microbianas, así como con una mayor similitud en la composición de la microbiota. Por último, en mujeres postmenopáusicas con hipercolesterolemia moderada se observa que la presencia de GOS (4,3 g/250 mL) no influye en el efecto hipocolesterolemiante de las bebidas enriquecidas con EV (2 g/250 mL). Además, la adición del prebiótico no modifica la biodisponibilidad y la fermentación colónica de los esteroles. Se confirma que, en presencia de altas concentraciones de EV, se produce una mayor excreción fecal de colesterol y se favorece su metabolización a través de rutas indirectas. Por lo tanto, los resultados obtenidos indican que la adición de GOS a bebidas a base de zumo de frutas y leche enriquecidas con EV no modifican la bioaccesibilidad/biodisponibilidad de los esteroles, ni el efecto hipocolesterolemiante de los EV. A pesar de que el metabolismo de los esteroles se ve favorecido por la presencia de GOS en ensayos in vitro, estos resultados no se reflejan en el estudio in vivo

Do cultural and creative entrepreneurs make affectively driven decisions? Not when they evaluate their opportunities

Our research studies the influence of positive affect on entrepreneurs' evaluations of opportunities (i.e. novelty assessments and entrepreneurial selection) as well as how this influence may be different for entrepreneurs belonging to cultural and creative industries. Drawing on arguments on the role of affect in cognition and considering the particular situational and individual-level factors of entrepreneurship in cultural and creative industries, we hypothesize that positive affect influences entrepreneurs' opportunity evaluation. We also hypothesize that this effect of positive affect is barely present for cultural and creative entrepreneurs. We test our hypotheses in a sample of nascent entrepreneurs who took part in entrepreneurship training programmes in six incubators in Spain, who we asked to evaluate their own opportunity. Our results show that positive affect positively impacts the perceived novelty and entrepreneurial selection of non-creative entrepreneurs though this impact is limited for cultural and creative entrepreneurs

How legumes recognize rhizobia

Legume plants have developed the capacity to establish symbiotic interactions with soil bacteria (known as rhizobia) that can convert N2 to molecular forms that are incorporated into the plant metabolism. The first step of this relationship is the recognition of bacteria by the plant, which allows to distinguish potentially harmful species from symbiotic partners. The main molecular determinant of this symbiotic interaction is the Nod Factor, a diffusible lipochitooligosaccharide molecule produced by rhizobia and perceived by LysM receptor kinases; however, other important molecules involved in the specific recognition have emerged over the years. Secreted exopolysaccharides and the lipopolysaccharides present in the bacterial cell wall have been proposed to act as signaling molecules, triggering the expression of specific genes related to the symbiotic process. In this review we will briefly discuss how transcriptomic analysis are helping to understand how multiple signaling pathways, triggered by the perception of different molecules produced by rhizobia, control the genetic programs of root nodule organogenesis and bacterial infection. This knowledge can help to understand how legumes have evolved to recognize and establish complex ecological relationships with particular species and strains of rhizobia, adjusting gene expression in response to identity determinants of bacteria.Facultad de Ciencias Exacta

How legumes recognize rhizobia

Legume plants have developed the capacity to establish symbiotic interactions with soil bacteria (known as rhizobia) that can convert N2 to molecular forms that are incorporated into the plant metabolism. The first step of this relationship is the recognition of bacteria by the plant, which allows to distinguish potentially harmful species from symbiotic partners. The main molecular determinant of this symbiotic interaction is the Nod Factor, a diffusible lipochitooligosaccharide molecule produced by rhizobia and perceived by LysM receptor kinases; however, other important molecules involved in the specific recognition have emerged over the years. Secreted exopolysaccharides and the lipopolysaccharides present in the bacterial cell wall have been proposed to act as signaling molecules, triggering the expression of specific genes related to the symbiotic process. In this review we will briefly discuss how transcriptomic analysis are helping to understand how multiple signaling pathways, triggered by the perception of different molecules produced by rhizobia, control the genetic programs of root nodule organogenesis and bacterial infection. This knowledge can help to understand how legumes have evolved to recognize and establish complex ecological relationships with particular species and strains of rhizobia, adjusting gene expression in response to identity determinants of bacteria.Facultad de Ciencias Exacta

Liberação sinaptossomal de glutamato induzida pela fração Bc2 do veneno da anêmona do mar Budonosoma caissarum /

Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas

Cover Crops and Corn Residue Removal: Impacts on Soil Hydraulic Properties and Their Relationships with Carbon

Large-scale crop residue removal may negatively affect soil water dynamics. Integrating cover crop (CC) with crop residue management can be a strategy to offset potential adverse effects of residue removal. We studied: (i) the impact of corn (Zea mays L.) residue removal (56%) with and without the use of winter rye (Secale cereale L.) CC on soil hydraulic properties, (ii) whether CC would ameliorate residue removal effects on hydraulic properties, and (iii) relationships of hydraulic properties with soil organic C (SOC) and other properties under irrigated no-till continuous corn on a silt loam in south central Nebraska after 5 and 6 yr of management. Cover crops did not affect soil hydraulic properties. However, residue removal reduced cumulative water infiltration by about 45% in one year. Across years, residue removal reduced plant available water (PAW) by 32% and mean weight diameter of water-stable aggregates (MWD) by 23% for the upper 5-cm soil depth. Under no CC, residue removal reduced SOC concentration by 25% in the 0- to 5-cm and by 11% in the 5- to 10-cm depths. Under residue removal, CC increased SOC concentration by 18% in the 0- to 5-cm and by 8% in the 5 to 10-cm depths. Cover crop did not completely offset the residue removal-induced decrease in SOC concentration in the upper 5-cm depth. Plant available water decreased as SOC concentration and MWD decreased. After 6 yr, corn residue removal adversely affected soil hydraulic properties and SOC concentration, but CC was unable to fully offset such adverse impacts

Compensation of biased excitation effects for MLS-based nonlinear systems' identification

MLS-based identification of nonlinear systems is largely affected by deviations in the excitation signal amenable to the combined effect of DC-offset and an arbitrary gain. These induce orthogonality loss in the MLS filter bank output, thus invalidating the underlying identification construction. In this paper we present a correction algorithm to derive the corrected Volterra kernels from the biased estimations provided by the standard MLS-based procedure