Caracterización de los principales genes y metabolitos responsables del aumento de la acidez durante la maduración de la chirimoya (annona cherimola mill.)

Tesis (Magister en Biotecnología)La chirimoya (Annona cherimola Mill.) es un fruto climatérico, subtropical del género Annonaceae. Madura rápidamente entre 6 a 7 días, tiempo en el cual el fruto se ablanda, el almidón se reduce a azúcares más simples y a diferencia de otros frutos la acidez aumenta para dar su sabor característico. Al igual que en otros frutos climatéricos, la producción de los ácidos orgánicos puede ser modulada por la acción de la hormona etileno. En manzana y plátano se ha descrito que en la maduración es etileno-dependiente, mientras que en otros frutos, como en melón o tomate es etileno-independiente. Sin embargo, no se ha descrito ninguna relación entre la acción del etileno, la acumulación de los ácidos orgánicos en la chirimoya ni su regulación a nivel bioquímico ni molecular. Por esto en esta Tesis, se analizó el comportamiento del metabolismo de los ácidos orgánicos a nivel de transcritos, mediante el estudio de los cambios en los principales genes involucrados en su síntesis y degradación; a nivel proteico, con el estudio de la actividad en las enzimas claves de este metabolismo; y a nivel de metabolitos, mediante el estudio en la acumulación de los ácidos orgánicos preponderantes (málico y cítrico) durante la maduración de la variedad “Concha Lisa”, en respuesta a la inhibición de la acción del etileno. De los 9 genes relacionados a este metabolismo identificados en chirimoya en este trabajo, se observó un aumento en la expresión de dos genes de síntesis, el que codifica para la malato deshidrogenasa dependiente de NAD (cyNAD-MDH) y el de la citrato sintasa (mCS), aumento que se correlacionaría con el incremento medido para cada ácido, lo que nos indicaría que estos genes serían claves para explicar el aumento de la acidez durante la maduración de la chirimoya. Por otra parte, nuestros resultados indican que el etileno no estaría regulando la acidez titulable de la chirimoya, pero si la acumulación de los ácidos málico y cítrico. A su vez, el etileno estaría regulando los genes involucrados en la degradación del ácido málico y cítrico; NADP-ME, ACON, ATP-CS y PEPC, y el de síntesis de ácido málico gNAD-MDH, en los cuales se ve alterada su transcripción durante la maduración, como también en los genes principales relacionados a la síntesis de ambos ácidos (cyNAD-MDH y mCS) al compararse los tratamientos con Etileno y 1-MCP.Flavor is a major quality attribute in fruit formed by a mixture of volatile compounds, sugar and acid levels, typical of each fruit. Cherimoya (Annona cherimola Mill.) is a climacteric subtropical fruit which shows an acidity increase during ripening in contrast to most fruits. The hypothesis of this study is: “Ethylene regulates organic acids metabolism in cherimoya, causing a transcript increase of genes encoding PEPC and NAD-MDH enzymes and a transcript decrease of NADP-ME and ACON, resulting in malic and citric acid accumulation”. For this, “Concha Lisa” variety cherimoyas were harvested and stored at 20°C under ethylene, 1-MCP and control conditions. To characterize the ripening process, ethylene production, respiration rate, flesh firmness, soluble solids and titratable acidity were determined and HPLC analysis was conducted for malic and citric acid quantitation. Additionally, expression of genes encoding key enzymes involved in the synthesis and degradation of these metabolites was determined by real-time PCR and activity assays were performed to observe the activity of these enzymes. Results show that all the measured ripening parameters were delayed by 1-MCP and the ethylene regulates the accumulation of malic and citric acid but not the titratable acidity. In addition, we achieve nine genes related to the organic acid metabolism, cyNAD-MDH and mCS are related directly at the increase of malic and citric acid respectively, and ethylene is related in the regulation of this genes together at the genes related to the degradation of this acids, specifically NADP-ME, gNAD-MDH, ACON, ATP-CS and PEP-C. For this and literature reviews, we postulate that the accumulation of this organic acids is for storage and the synthesis in cherimola fruit

The Unusual Acid-Accumulating Behavior during Ripening of Cherimoya (Annona cherimola Mill.) is Linked to Changes in Transcription and Enzyme Activity Related to Citric and Malic Acid Metabolism

Indexación: Web of ScienceCherimoya (Annona cherimola Mill.) is a subtropical fruit characterized by a significant increase in organic acid levels during ripening, making it an interesting model for studying the relationship between acidity and fruit flavor. In this work, we focused on understanding the balance between the concentration of organic acids and the gene expression and activity of enzymes involved in the synthesis and degradation of these metabolites during the development and ripening of cherimoya cv. "Concha Lisa". Our results showed an early accumulation of citric acid and other changes associated with the accumulation of transcripts encoding citrate catabolism enzymes. During ripening, a 2-fold increase in malic acid and a 6-fold increase in citric acid were detected. By comparing the contents of these compounds with gene expression and enzymatic activity levels, we determined that cytoplasmic NAD-dependent malate dehydrogenase (cyNAD-MDH) and mitochondrial citrate synthase (mCS) play important regulatory roles in the malic and citric acid biosynthetic pathways.http://www.mdpi.com/1420-3049/21/5/39

Discovering HIV related information by means of association rules and machine learning

Acquired immunodeficiency syndrome (AIDS) is still one of the main health problems worldwide. It is therefore essential to keep making progress in improving the prognosis and quality of life of affected patients. One way to advance along this pathway is to uncover connections between other disorders associated with HIV/AIDS-so that they can be anticipated and possibly mitigated. We propose to achieve this by using Association Rules (ARs). They allow us to represent the dependencies between a number of diseases and other specific diseases. However, classical techniques systematically generate every AR meeting some minimal conditions on data frequency, hence generating a vast amount of uninteresting ARs, which need to be filtered out. The lack of manually annotated ARs has favored unsupervised filtering, even though they produce limited results. In this paper, we propose a semi-supervised system, able to identify relevant ARs among HIV-related diseases with a minimal amount of annotated training data. Our system has been able to extract a good number of relationships between HIV-related diseases that have been previously detected in the literature but are scattered and are often little known. Furthermore, a number of plausible new relationships have shown up which deserve further investigation by qualified medical experts

Experiencias de innovación educativa en la Universidad de Murcia (2008)

Resumen tomado de la publicaciónSe recogen diversos proyectos de innovación realizados por el profesorado de la Universidad de Murcia. Son experiencias de adaptación, en las que se han diseñado, aplicado y evaluado diversas acciones de enseñanza, como : el aprendizaje basado en problemas, portafolios, aprendizaje cooperativo, planes de acción tutorial o curso cero de acogida de estudiantes, entre otros. Se trata de dar respuesta al cambio que requiere el proceso de de Convergencia Europea.MurciaBiblioteca de Educación del Ministerio de Educación, Cultura y Deporte; Calle San Agustín 5 -3 Planta; 28014 Madrid; Tel. +34917748000; [email protected]