Nanostructural differences in pectic polymers isolated from strawberry fruits with low expression levels of pectate lyase or polygalacturonase genes

Our research group has obtained transgenic strawberry plants expressing antisense sequences of either a pectate lyase (APEL lines) [1] or a polygalacturonase gene (APG lines) [2]. Both genes encode ripening-specific endo-pectinases with a common target, deesterified homogalacturonans, but each enzyme act by a different mechanism and pH range. Ripe fruits from both transgenic genotypes were significantly firmer than control, being APG fruits on average 25% firmer than APEL fruits. Cell wall analysis of both transgenic genotypes indicated that pectin fractions extracted with CDTA and sodium carbonate were significantly modified in transgenic fruits [2,3]. To gain insight in the role of these pectinases in pectin disassembly during ripening, CDTA and Na2CO3 pectins have been analyzed by atomic force microscopy (AFM). APEL and APG CDTA pectins had similar contour lengths but both were significantly longer than control. Similarly, APG carbonate chains were longer than control, showing APEL carbonate chains an intermediate length. Furthermore, transgenic pectins displayed a more complex branching pattern and a higher number of micellar aggregates, especially in the sodium carbonate fractions of APG samples. Acid hydrolysis of carbonate pectins reduced the number of micellar aggregates. AFM analyses confirm that the inhibition of both pectinases reduces pectin disassembly, and also suggest that each pectinase acts on specific pectin domains. Particularly, polygalacturonase silencing induces more significant pectin modifications, nicely correlated with the firmer phenotype of APG fruits, than the down-regulation of pectate lyase

Utilización de sensores remotos para determinar cambio de uso de la tierra en Costa Rica: caso del Área de Conservación Osa (1992-2005) y del Área de Conservación Tempisque

Proyecto de Graduación (Licenciatura en Ingeniería Forestal). Instituto Tecnológico de Costa Rica, Escuela de Ingeniería Forestal, 2008.El Programa de Servicios Ambientales (PSA) se inició formalmente en 1997 en Costa Rica. Se diseñó como un mecanismo para contrarrestar la deforestación y degradación ambiental que venía sufriendo el país desde la década de los sesenta. Se evaluaron los cambios de uso de la tierra mediante fotografías áreas de 1992 y 2005 en el Área de Conservación Osa, y el uso de la tierra en 1992 en el Área de Conservación Tempisque mediante una imagen satelital. La evaluación de 65 522 ha en el Área de Conservación Osa, registró un incremento del área de la categoría Bosque Natural, pasando de 28 606 ha a 31 247 ha. Las categorías Cultivos Agrícolas, Agua y Otros (Nubes, Playas, Reforestación, Sombras, Zonas Urbanas y Falta de Cobertura) registraron incrementos de 0,5%; 0,9% y 8,0% respectivamente. Las categorías Potreros y Humedales redujeron su área un 12,7% y 0,8% respectivamente. El uso del tierra en 309 230 ha en el Área de Conservación Tempisque, indicó un porcentaje de Bosque Natural de 64,7%, mientras que los Potreros un 33,3%. Los demás usos no superaron el 0,7%

Parasitoidismo natural en huevos de diatraea spp. por trichogramm sp. y Telenomus sp., en dos zonas cañeras de Costa Rica

Proyecto de Graduación (Licenciatura en Ingeniería en Agronomía) Instituto Tecnológico de Costa Rica. Escuela de Agronomía, 2007.El Barrenador Común del Tallo (Diatraea spp.) es catalogada como una de las principales plagas de la caña de azúcar. Trichogramma sp. y Telenomus sp. son parasitoides naturales de huevo que atacan muchas especies de lepidóptera entre ellas al Barrenador Común del Tallo. Este estudio determinó la incidencia, la viabilidad y el parasitismo natural en los huevos de Diatraea spp., en el Valle Central y la Zona Norte de Costa Rica. Se muestrearon dos zonas cañeras del país, con tres lotes de una hectárea exacta cada una, durante cinco meses. Por muestreo se extrajeron 1000 hojas seleccionadas al azar, para ser evaluadas. Los resultados muestran que la incidencia de posturas es inferior al 1% en ambas zonas de estudios. La cantidad de huevos viables por muestreo fue inferior a 45 para ambas zonas, mientras que la cantidad de huevos vanos por muestreo fue inferior a 25, para la zona del Valle Central y cero para la Zona Norte. Al evaluar el grado de huevos parasitados, el Valle Central mostró la mayor incidencia (28 huevos), mientras que la Zona Norte mostró la menor (7). Ambos parasitoides tienen una mayor incidencia en el Valle Central que en la Zona Norte. De acuerdo al análisis estadístico, las variaciones presentadas para la variables incidencia de posturas para la zona, huevos parasitados por Trichogramma sp. para la zona y localidad fueron significativas (p >0,01). Este estudio concluyó que la Zona del Valle Central tuvo los valores más altos para las diferentes variables evaluadas

Nanostructural changes in cell wall pectins during strawberry fruit ripening assessed by atomic force microscopy

Rapid loss of firmness occurs during strawberry (Fragaria × ananassa Duch) ripening, resulting in a short shelf life and high economic losses. The disassembly of cell walls is considered the main responsible for fruit softening, being pectins extensively modified during strawberry ripening (Paniagua et al. 2014). Atomic force microscopy allows the analysis of individual polymer chains at nanostructural level with a minimal sample preparation (Morris et al., 2001). The main objective of this research was to compare pectins of green and red ripe strawberry fruits at the nanostructural level to shed light on structural changes that could be related to softening. Cell walls from strawberry fruits were extracted and fractionated with different solvents to obtain fractions enriched in a specific component. The yield of cell wall material, as well as the amount of the different fractions, decreased in ripe fruits. CDTA and Na2CO3 fractions underwent the largest decrements, being these fractions enriched in pectins supposedly located in the middle lamella and primary cell wall, respectively. Uronic acid content also decreased significantly during ripening in both pectin fractions, but the amount of soluble pectins, those extracted with phenol:acetic acid:water (PAW) and water increased in ripe fruits. Monosaccharide composition in CDTA and Na2CO3 fractions was determined by gas chromatography. In both pectin fractions, the amount of Ara and Gal, the two most abundant carbohydrates, decreased in ripe fruits. The nanostructural characteristics of CDTA and Na2CO3 pectins were analyzed by AFM. Isolated pectic chains present in the CDTA fraction were significantly longer and more branched in samples from green fruits than those present in samples obtained from red fruit. In spite of slight differences in length distributions, Na2CO3 samples from unripe fruits displayed some longer chains at low frequency that were not detected in ripe fruits. Pectin aggregates were more frequently observed in green fruit samples from both fractions. These results support that pectic chain length and the nanostructural complexity of the pectins present in CDTA and Na2CO3 fractions diminish during strawberry fruit development, and these changes, jointly with the loss of neutral sugars, could contribute to the solubilization of pectins and fruit softening. Paniagua et al. (2014). Ann Bot, 114: 1375-1383 Morris et al. (2001). Food Sci Tech 34: 3-10 This research was supported by FEDER EU Funds and the Ministerio de Educación y Ciencia of Spain (grant reference AGL2011-24814)Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Unravelling the nanostructure of strawberry fruit pectins by atomic force microscopy

Atomic force microscopy (AFM) allows the analysis of individual polymers at nanostructural level with a minimal sample preparation. This technique has been used to analyse the pectin disassembly process during the ripening and postharvest storage of several fleshy fruits. In general, pectins analysed by AFM are usually visualized as isolated chains, unbranched or with a low number of branchs and, occasionally, as large aggregates. However, the exact nature of these structures is unknown. It has been suggested that pectin aggregates represent a mixture of rhamnonogalacturonan I and homogalacturonan, while isolated chains and their branches are mainly composed by polygalacturonic acid. In order to gain insight into the nature of these structures, sodium carbonate soluble pectins from ripe strawberry (Fragaria x ananassa, Duch.) fruits were subjected to enzymatic digestion with endo-Polygalacturonase M2 from Aspergillus aculeatus, and the samples visualized by AFM at different time intervals. Pectins isolated from control, non-transformed plants, and two transgenic genotypes with low level of expression of ripening-induced pectinase genes encoding a polygalacturonase (APG) or a pectate lyase (APEL) were also included in this study. Before digestion, isolated pectin chains from control were shorter than those from transgenic fruits, showing number-average (LN) contour length values of 73.2 nm vs. 95.9 nm and 91.4 nm in APG and APEL, respectively. The percentage of branched polymers was significantly higher in APG polyuronides than in the remaining genotypes, 33% in APG vs. 6% in control and APEL. As a result of the endo-PG treatment, a gradual decrease in the main backbone length of isolated chains was observed in the three samples. The minimum LN value was reached after 8 h of digestion, being similar in the three genotypes, 22 nm. By contrast, the branches were not visible after 1.5-2 h of digestion. LN values were plotted against digestion time and the data fitted to a first-order exponential decay curve, obtaining R2 values higher than 0.9. The half digestion time calculated with these equations were similar for control and APG pectins, 1.7 h, but significantly higher in APEL, 2.5 h, indicating that these polymer chains were more resistant to endo-PG digestion. Regarding the pectin aggregates, their volumes were estimated and used to calculate LN molecular weights. Before digestion, control and APEL samples showed complexes of similar molecular weights, 1722 kDa, and slightly higher than those observed in APG samples. After endo-PG digestion, size of complexes diminished significantly, reaching similar values in the three pectin samples, around 650 kDa. These results suggest that isolated polymer chains visualized by AFM are formed by a HG domain linked to a shorter polymer resistant to endo-PG digestion, maybe xylogalacturonan or RG-I. The silencing of the pectate lyase gene slightly modified the structure and/or chemical composition of polymer chains making these polyuronides more resistant to enzymatic degradation. Similarly, polygalacturonic acid is one of the main component of the aggregates.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Coverage analysis of Scopus: A journal metric approach

Our aim is to compare the coverage of the Scopus database with that of Ulrich, to determine just how homogenous it is in the academic world. The variables taken into account were subject distribution, geographical distribution, distribution by publishers and the language of publication. The analysis of the coverage of a product of this nature should be done in relation to an accepted model, the optimal choice being Ulrich’s Directory, considered the international point of reference for the most comprehensive information on journals published throughout the world. The results described here allow us to draw a profile of Scopus in terms of its coverage by areas – geographic and thematic – and the significance of peer-review in its publications. Both these aspects are highly pragmatic considerations for information retrieval, the evaluation of research, and the design of policies for the use of scientific databases in scientific promotion

Phase-locking of a Nonlinear Optical Cavity via Rocking: Transmuting Vortices into Phase Patterns

We report experimental observation of the conversion of a phase-invariant nonlinear system into a phase-locked one via the mechanism of rocking [G. J. de Valcarcel and K. Staliunas, Phys. Rev. E 67, 026604 (2003)]. This conversion results in that vortices of the phase-invariant system are being replaced by phase patterns such as domain walls. The experiment is carried out on a photorefractive oscillator in two-wave mixing configuration.A model for the experimental device is given that reproduces the observed behavior.Comment: 9 pages and 4 figure

AFM study of strawberry pectin nanostructure and its relevance on fruit texture

Atomic force microscopy (AFM) has been used to characterize the nanostructure of cell wall pectins during strawberry fruit growth and ripening, as well as in transgenic fruits with pectinase genes downregulated. This technique allows the imaging of individual polymers at high magnification with minimal sample preparation. AFM studies during fruit development show that pectin size, ramification and aggregation is reduced in ripe fruits. Additionally, transgenic lines with different pectinase genes downregulated (polygalacturonase, pectate lyase and B-galactosidase) also show a more complex pectin nanostructure, including longer chains, higher branching degree and larger presence of aggregates. In all those cases the higher pectin complexity at nanoscale correlates with a reduced softening in strawberry fruits at macroscale level. Globally, our results support the key role of pectins in fruit structure and highlights the use of AFM as a powerful tool to gain insights about the bases of textural fruit quality not only in strawberry, but also in other commercial crops.AGL2017-86531-C2-1-R, Ministerio de Economía, Industria y Competitividad of Spain and FEDER EU funds. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Aplicación de la dinamometría isocinética para establecer perfiles de riesgo de lesión isquiosural en futbolistas profesionales. [The use of isokinetic dynamometry to establish risk profiles of hamstring injury in professional football players].

<p align="justify">Las lesiones en la musculatura isquiosural son frecuentes en el fútbol profesional y han sido relacionadas con el desequilibrio entre la fuerza de los flexores y extensores de rodilla. El objetivo de nuestro estudio fue comprobar si la ratio de fuerza máxima excéntrica de flexores/concéntrica de extensores (ratio Flexexc30/Extcon240) y el ángulo de rodilla donde la musculatura isquiosural alcanza su máximo momento de fuerza, son variables útiles para establecer perfiles de riesgo de lesión isquiosural en futbolistas profesionales. Veinte jugadores de un equipo de la Segunda División de la Liga de Fútbol Profesional realizaron bilateralmente un test isocinético de flexión excéntrica de rodilla a 30º/s y extensión concéntrica de rodilla a 240º/s durante la pretemporada. Tras calcular la ratio Flexexc30/Extcon240 y el ángulo de máximo momento de fuerza, se registraron las lesiones sufridas por los jugadores a lo largo de la temporada. Los resultados mostraron que dos de los cinco jugadores lesionados presentaron ratios Flexexc30/Extcon240 menores de 0.89, valor que ha sido utilizado previamente para determinar el desequilibrio entre la musculatura flexora y extensora de rodilla y el riesgo de lesión (Croisier, Ganteaume, Binet, Genty, y Ferret, 2008). Además, otros dos de los jugadores lesionados obtuvieron ratios entre 0.93 y 1.00. Por otro lado, no se encontraron diferencias en el ángulo de máximo momento de fuerza entre jugadores lesionados y no lesionados. Estos resultados indican que la ratio Flexexc30/Extcon240 puede ser un índice útil para determinar el riesgo de lesión isquiosural en futbolistas profesionales.</p>Abstract<p align="justify">Hamstring injuries are common in professional football and have been related to the imbalance between knee flexor and extensor strength. The aim of our study was to establish whether the flexor eccentric/extensor concentric strength ratio (Flexexc30/Extcon240 ratio) and the knee angle where the peak torque of the hamstring musculature was found, are useful variables to establish risk profiles for hamstring injury in professional football players. Twenty players of a Second Division team of the Liga de Fútbol Profesional bilaterally performed an isokinetic test of eccentric knee flexion at 30º/s and concentric knee extension at 240º/s during the pre-season. The Flexexc30/Extcon240 ratio and the knee angle of peak torque were calculated, and the players’ injuries were registered throughout the season. The results showed that two of the five injured players had Flexexc30/Extcon240 ratios lower than 0.89, value that has been previously used to determine the imbalance between knee flexor and extensor strength and the risk of injury (Croisier, Ganteaume, Binet, Genty, and Ferret, 2008). In addition, another two injured players obtained ratios between 0.93 and 1.00. On the other hand, no differences in the knee angle of peak torque between injured and non-injured players were found. These results indicate that the Flexexc30/Extcon240 ratio may be a useful index to determine the risk of hamstring injury in professional football players.</p>http://dx.doi.org/10.5232/ricyde2013.0340

Limb Versus Precordial ECG Leads as Improved Predictors of Electrical Cardioversion Outcome in Persistent Atrial Fibrillation

[EN] Electrical cardioversion (ECV) is an effective and low-cost rhythm control strategy for persistent atrial fibrillation (AF). Because of its limited mid- and long-term success rates, prediction of early failure could avoid patients with reduced chance to maintain sinus rhythm (SR). To this end and due to its proximity to the right atrium, several indices characterizing atrial activity have been proposed based on lead V1. However, information from other leads has been discarded to date. Hence, this work studies how effective some common indices computed over the whole set of 12 standard ECG leads are in predicting ECV outcome. Precisely, amplitude, dominant frequency, and sample entropy were computed from the fibrillatory (f-) waves extracted for each one of 12 standard leads acquired before ECV from 58 patients in persistent AF. The classification between the patients who relapsed to AF and maintained sinus rhythm after a follow-up of 4 weeks achieved by these parameters was better from limb lead II than from V1, thus reporting improvements about 6 and 12%. As a consequence, characterization of f-waves from the more accessible limb lead II has proven to be the best choice to improve AF ECV outcome prediction from the ECG.This research was funded by the projects DPI2017-83952C3 from MINECO/AEI/FEDER EU, SBPLY/17/180501/000411 from "Junta de Castilla La Mancha" and AICO/2019/036 from "Generalitat Valenciana".Cirugeda, EM.; Calero, S.; Quesada, A.; Hidalgo, VM.; Rieta, JJ.; Alcaraz, R. (2020). Limb Versus Precordial ECG Leads as Improved Predictors of Electrical Cardioversion Outcome in Persistent Atrial Fibrillation. IEEE. 1-4. https://doi.org/10.22489/CinC.2020.373S1