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Este estudio evaluó la actividad pectinolítica de las enzimas producidas por el aislado Aspergillus niger M6P21 (P. Micheli, 1729), utilizando albedo de piña, albedo de maracuyá y una combinación de ambos como únicas fuentes de carbono, con pectina comercial como control. El aislado M6P21 fue obtenido de un cultivo de piña en el distrito Sarandelo de Lorica, Córdoba, Colombia. La producción enzimática se evaluó en cuatro tratamientos: albedo de piña, albedo de maracuyá, su mezcla y pectina comercial. La actividad pectinolítica se monitoreó durante tres días, y los resultados se expresaron como concentración de azúcares reductores. Los hallazgos demostraron una actividad enzimática notable: 0,2816 g/L para el albedo de piña, 0,2740 g/L para el albedo de maracuyá, 0,3923 g/L para la mezcla de sustratos y 0,3046 g/L para la pectina comercial. El análisis estadístico mediante ANOVA arrojó un valor – p  de 0,9383, lo que indica que no hubo diferencias significativas entre los tratamientos. Estos resultados resaltan el potencial de Aspergillus niger M6P21 para la producción de pectinasas a partir de subproductos agroindustriales, ofreciendo un enfoque biotecnológico sostenible para la valorización de residuos frutales en las industrias alimentaria y biotecnológica. This study evaluated the pectinolytic activity of enzymes produced by the Aspergillus niger M6P21 isolate (P. Micheli, 1729), using pineapple albedo, passion fruit albedo, and a combination of both as sole carbon sources, with commercial pectin serving as the control. The M6P21 isolate was isolated from a pineapple crop in the Sarandelo district of Lorica, Córdoba, Colombia. Enzyme production was assessed across four treatments: pineapple albedo, passion fruit albedo, their mixture, and commercial pectin. Pectinolytic activity was monitored over three days, with results expressed as reducing sugar concentration. The findings demonstrated notable enzymatic activity: 0.2816 g/L for pineapple albedo, 0.2740 g/L for passion fruit albedo, 0.3923 g/L for the mixed substrates, and 0.3046 g/L for commercial pectin. Statistical analysis using ANOVA yielded a p-value of 0.9383, indicating no significant differences among the treatments. These results highlight the potential of Aspergillus niger M6P21 for pectinase production from agro-industrial by-products, offering a sustainable biotechnological approach for the valorization of fruit waste in the food and biotechnology industries.

Contexto: Factores dietarios poco saludables se han asociado con aumento de riesgo cardiovascular, uno de ellos; consumo de azúcar.  Objetivo: Búsqueda, evaluación y análisis de la mejor evidencia disponible sobre el consumo de azúcar y desenlaces mayores cardiovasculares. Metodología: Revisión sistemática de la literatura. Evaluación cuantitativa entre consumo de azúcar y alguno de los siguientes eventos cardiovasculares mayores (muerte cardiovascular, infarto agudo de miocardio no fatal o accidente cerebrovascular no fatal). Se incluyeron participantes mayores de 18 años no gestantes, sin cardiopatía congénita.  Resultados: Se incluyeron 31 estudios primarios (27 estudios de cohortes y 4 estudios de casos y controles). Veintiuno evaluaron el consumo de azúcar e infarto agudo de miocardio, 12 consumo de azúcar y accidente cerebrovascular y 6 consumo de azúcar y muerte cardiovascular. Para los 3 desenlaces los resultados fueron controversiales, sin embargo, con significancia estadística en varios estudios para la asociación en cuestión, al evaluarse el consumo de azúcar por carga glucémica, índice glucémico, carbohidratos totales, entre otros. Conclusiones: Sin bien la evidencia es contradictoria, sugiere de forma consistente a partir de estudios de cohorte que los carbohidratos con alto índice glucémico, azucares añadidos y bebidas azucaradas, aumentan el riesgo de presentar eventos adversos cardiovasculares mayores como infarto agudo de miocardio, ataque cerebrovascular y muerte cardiovascular.

Introduction. Consumers and processors value tomatoes with high fruit sugar content; however, most breeding and cultural practices negatively impact this trait. Wild tomato species can accumulate two- to three-fold more fruit sugar than cultivars and are proving to be valuable both as a source of high-sugar loci to broaden the genetic base of currently produced cultivars, and as research material to understand this trait. Synthesis. While cutting-edge genomic approaches have taught us much about fruit phenotypes, it is still important to assess fruit enzyme activities and metabolic fluxes in lines with contrasting fruit sugar accumulation. These metabolic functions are closest to the ripe fruit sugar trait. In this review, we focus our attention on the biochemical pathways, especially starch biosynthesis, that may influence tomato fruit sugars. We try where possible to put this information into a physiological context because together they influence yield. We compare and contrast sugar metabolism in cultivars and wild tomato species and identify factors that may influence differences in their fruit size. Conclusion. Although difficult, we show that it is possible to develop fruit with high horticultural yield and use the breeding line ‘Solara’ as an example. In addition, we suggest avenues of further investigation to understand the regulation and control of fruit carbohydrate content. Introduction. Les consommateurs et les industriels apprécient les tomates avec un fort taux en sucres, mais la plupart des pratiques culturales et d’amélioration ont un impact négatif sur ce caractère. Les espèces de tomate sauvage peuvent accumuler 2 ou 3 fois plus de sucres dans le fruit que des cultivars et elles s’avèrent précieuses à la fois comme une source de loci à haute teneur en sucres pour élargir la base génétique des cultivars actuellement produits, et comme matériel de recherche pour comprendre ce caractère. Synthèse. Alors que les approches génomiques de pointe nous ont appris beaucoup sur le phénotype des fruits, il reste important d’évaluer l’activité des enzymes de fruits et les flux métaboliques dans des lignées présentant des situations contrastées d’accumulation de sucres dans les fruits. Ces fonctions métaboliques sont les plus proches du caractère de teneur en sucres dans le fruit mûr. Dans cette synthèse, nous nous sommes focalisés sur les voies biochimiques, en particulier sur la biosynthèse de l’amidon qui peut influencer les sucres dans le fruit des tomates. Nous essayons autant que possible de mettre cette information dans un contexte physiologique car, ensemble, ils influencent le rendement. Nous comparons et mettons en contraste le métabolisme des sucres dans les cultivars et les espèces sauvages de tomate et nous identifions les facteurs qui peuvent influencer des différences de taille des fruits. Conclusion. Bien que cela soit difficile, nous montrons qu’il est possible de produire des fruits présentant un rendement horticole élevé et nous utilisons la lignée sélectionnée “ Solara ” comme exemple. En outre, nous suggérons des pistes de recherches supplémentaires pour comprendre la régulation et le contrôle du contenu en glucides des fruits. Introducción. Los consumidores e industriales aprecian los tomates con un fuerte índice de azúcares, pero la mayoría de las prácticas relativas al cultivo y de mejora tienen un impacto negativo sobre este rasgo característico. Las especies de tomate salvaje pueden acumular 2 ó 3 veces más azúcares en el fruto que los cultivares, y resultan ser apreciadas como fuente de loci de alto contenido en azúcares para aumentar la base genética de los cultivares actualmente producidos y como material de investigación para comprender dicho rasgo característico. Síntesis. A pesar de que los acercamientos genómicos punteros nos hayan enseñado mucho sobre el fenotipo de los frutos, sigue siendo importante evaluar la actividad de las encimas de los frutos, así como los flujos metabólicos en líneas que presenten situaciones contrastadas de acumulación de azúcares en los frutos. Dichas funciones metabólicas son las que más se acercan al rasgo característico del contenido de azúcares en el fruto maduro. En esta síntesis, nos centramos en las vías bioquímicas, particularmente en la biosíntesis del almidón, que puede influenciar los azúcares en el fruto del tomate. Intentamos, en la medida de lo posible, situar esta información en un contexto fisiológico, ya que, conjuntamente, influencian el rendimiento. Comparamos y contrastamos el metabolismo de los azúcares en los cultivares y en las especies salvajes de tomate, e identificamos los factores que pueden influenciar las diferencias en el tamaño de los frutos. Conclusión. A pesar de la dificultad, ilustramos la posibilidad de producir frutos que presenten un elevado rendimiento y utilizamos la línea seleccionada “ Solara ” como ejemplo. Además, sugerimos vías de investigación suplementarias para comprender la regulación y el control del contenido de glúcidos de los frutos.

Cleft grafting methods were applied in order to evaluate the effect of grafting on tomato fruit yield and quality. The tomato cultivars used as scions were Yeni Talya, Swanson and Beri. The cultivars Beaufort and Arnold were used as rootstocks. The following characteristics of grafted and nongrafted plants were recorded: fruit index, number of fruits/truss, fruit weight, fruit yield, dry matter, pH, concentration of soluble solids, titratable acidity, concentrations of total sugar, lycopene and vitamin C. The results showed that fruit yield and fruit index, number of fruits/truss and fruit weights were improved by grafting. Fruit quality, measured in terms of concentrations of dry matter, soluble solids, total sugar, and vitamin C, was lower in grafted plants than in nongrafted ones. No significant difference in lycopene level and pH was found. Titratable acidity was improved by grafting. A positive effect of grafting was recorded when Beaufort was used as rootstock. These results showed that grafting could be an advantageous alternative in tomato production.

Introduction. Drought stress is the major factor affecting growth, development and production of walnut trees. In Iran, approximately 33 Mha of land is affected by salinization and drought stress. Finding genetic resources tolerant to drought stress at different growth stages is important for such semi-arid regions. Our aim was to understand better the adaptive mechanisms that enable different genotypes of walnut population to survive under drought stress, and to provide some useful clues for walnut tree breeding toward improved drought tolerance with utilization of existing drought-tolerant genetic resources. Materials and methods. To study the mechanism(s) involved in drought tolerance of some Persian walnut genotypes, drought stress was induced using polyethylene glycol-6000 to produce water potentials of 0 Mpa (control), –0.10 MPa, –0.50 MPa, –0.75 MPa, –1.00 MPa, –1.50 MPa and –2.00 MPa. The amount of proline and soluble sugar accumulation in four walnut genotypes (‘Panegine20’, ‘Lara’, ‘Serr’ and ‘Chandler’) were determined after being exposed to the various water potential levels. Results. The rates of seed germination in all genotypes were significantly reduced by low external water potentials. Plants exposed to water stress had a higher amount of soluble sugars in roots and shoots of tolerant genotypes (‘Panegine20’ and ‘Chandler’) and a lower amount of starch in their tissues. These results imply the important roles of soluble sugars as solutes conferring resistance to drought in these genotypes. The free proline levels were also increased in response to drought stress. They were higher in drought-tolerant genotypes than in sensitive ones (‘Lara’ and ‘Serr’). Proline increased more in shoots than in roots. However, the soluble sugar and starch fluctuations were higher in the roots. Conclusion. Our results support a direct correlation between the degree of drought stress and proline content. As a consequence, proline concentrations could be used as a biochemical marker of drought stress level in walnut plants. Introduction. Le stress dû à la sécheresse est le principal facteur influant sur la croissance, le développement et la production de noyers. En Iran, environ 33 Mha de terres sont affectées par la salinisation et la sécheresse. Trouver des ressources génétiques tolérantes à la sécheresse à différents stades de croissance est important pour ces régions semi-arides. Notre objectif a été de mieux comprendre les mécanismes adaptatifs qui permettent aux différents génotypes de noyers de survivre en conditions de stress hydrique et de fournir quelques indications utiles pour une amélioration de ces arbres vis-à-vis de la tolérance à la sécheresse en utilisant des ressources génétiques existantes. Matériel et méthodes. Pour étudier les mécanismes de certains génotypes de noyers persans impliqués dans la tolérance à la sécheresse, un stress hydrique a été induit en utilisant du polyéthylène glycol-6000 pour produire des potentiels hydriques de 0 Mpa (témoin), –0.10 MPa, –0.50 MPa, –0.75 MPa, –1.00 MPa, –1.50 MPa et –2.00 MPa. Le niveau d'accumulation de proline et de sucres solubles dans quatre génotypes de noyer ('Panegine20', 'Lara', 'Serr' et 'Chandler') a été déterminé après qu’ils ont été exposés aux différents niveaux de potentiels hydriques. Résultats. Pour les quatre génotypes étudiés, les taux de germination des semences ont été considérablement réduits par les bas potentiels hydriques. Les semis des génotypes tolérants ('Panegine20' et 'Chandler') exposés au stress hydrique ont présenté les plus grandes quantités de sucres solubles dans les racines et les tiges, mais une moindre quantité d’'amidon dans leurs tissus par rapport aux génotypes sensibles. Ces résultats suggèrent l'importance des sucres solubles comme solutés conférant, à ces génotypes, la résistance à la sécheresse. Les niveaux de proline libre ont également été augmentés en réponse à la sécheresse. Ils ont été plus élevés chez les génotypes tolérants à la sécheresse que chez les plus sensibles (‘Lara’ et ‘Serr '). La teneur en proline a davantage augmenté dans les tiges que dans les racines. Toutefois, les fluctuations du sucre soluble et de l'amidon ont été plus élevées dans les racines. Conclusion. Nos résultats confirment qu’il existe une corrélation directe entre le degré de stress hydrique et la teneur en proline dans les plantules. En conséquence, les concentrations en proline pourraient être utilisées comme marqueurs biochimiques du niveau de stress hydrique chez le noyer. Introducción. El estrés causado por la sequía es el factor principal que influye el crecimiento, el desarrollo y la producción de nogales. En Irán, cerca de 33 Mha de tierras están afectadas por la salinización y por la sequía. Es importante para estas regiones semi-áridas encontrar recursos genéticos que toleran la sequía en diferentes estadios de crecimiento. Nuestro objetivo fue comprender mejor los mecanismos de adaptación que permiten los diferentes genotipos de nogales sobrevivir en condiciones de estrés hídrico. También pretendimos aportar, mediante el empleo de los recursos genéticos existentes, algunas indicaciones útiles para una mejora de estos árboles con respecto a la tolerancia de la sequía. Material y métodos. Con el fin de estudiar los mecanismos de ciertos genotipos de nogales persas implicados en la tolerancia de la sequía, se indujo un estrés hídrico mediante el empleo del polietilenglicol-6000 para producir potenciales hídricos de 0 Mpa (testigo), –0.10 MPa, –0.50 MPa, –0.75 MPa, –1.00 MPa, –1.50 MPa y –2.00 MPa. El nivel de acumulación de prolina y de los azúcares solubles en cuatro genotipos de nogales (‘Panegine20’, ‘Lara’, ‘Serr’ y ‘Chandler’) se determinó tras su exposición a diferentes niveles de potenciales hídricos. Resultados. Para los cuatro genotipos estudiados, los valores de germinación de las semillas se redujeron considerablemente por los bajos potenciales hídricos. Las siembras de los genotipos tolerantes ('Panegine20' y 'Chandler') expuestos al estrés hídrico, en relación con los genotipos sensibles, presentaron las cantidades más grandes de azúcares solubles en las raíces y en las ramas, pero una cantidad menor de almidón en sus tejidos. Los resultados en cuestión sugieren la importancia de los azúcares solubles y solutos, que confieren a estos genotipos la resistencia a la sequía. Los niveles de prolina libre aumentaron igualmente en respuesta a la sequía. Fueron más elevados en los genotipos tolerantes a la sequía que en aquellos que eran más sensibles (‘Lara’ y ‘Serr'). El contenido en prolina aumentó considerablemente más en las ramas que en las raíces. No obstante, las fluctuaciones de azúcar soluble y del almidón fueron más elevadas en las raíces. Conclusión. Nuestros resultados confirman que existe una correlación directa entre el grado de estrés hídrico y el contenido en prolina en las plántulas. Por consecuente, las concentraciones de prolina podrían emplearse como marcadores bioquímicos del nivel de estrés hídrico en el nogal.

Sensory responses to the taste, smell, and texture of foods help determine food preferences and eating habits. However, sensory responses alone do not predict food consumption. The view that a \"sweet tooth\" leads to obesity through excess sugar consumption is overly narrow. In reality, there are multiple links between taste perceptions, taste preferences, food preferences, and food choices and the amount of food consumed. Taste responses are influenced by a range of genetic, physiological, and metabolic variables. The impact of taste factors on food intake further depends on sex and age and is modulated by obesity, eating disorders, and other pathologies of eating behavior. Food preferences and food choices of populations are further linked to attitudinal, social, and--probably most important--economic variables such as income. Nutrition education and intervention strategies aimed at improving population diets ought to consider sensory pleasure response to foods, in addition to a wide range of demographic and sociocultural variables

Sugar‐mediated regulation of gene expression is a mechanism controlling the expression of many different plant genes. In this review, a compilation of the genes encoding photosynthetic proteins, subject to this mode of regulation, is presented. Several groups have devised different screening strategies to obtain Arabidopsis mutants in sugar sensing and signalling. An overview of these strategies has been included. Sugar‐mediated regulation of gene expression is thought to require the hexokinase (HXK) protein. It has previously been shown that one such sugar, mannose, is capable of blocking germination in Arabidopsis. This inhibition is also mediated by HXK and occurs in the low millimolar concentration range. Here, the use of germination on mannose as an effective screening strategy for putative sugar sensing and signalling mutants is reported. T‐DNA‐ and EMS‐mutagenized collections were used to isolate 31 mannose‐insensitive germination (mig) mutants. With the use of these mutants, a comparison between this screen and other existing sugar‐sensing screens is presented.

Isopentenyl diphosphate, the common precursor of all isoprenoids, has been widely assumed to be synthesized by the acetate/mevalonate pathway in all organisms. However, based on in vivo feeding experiments, isopentenyl diphosphate formation in several eubacteria, a green alga, and plant chloroplasts has been demonstrated very recently to originate via a mevalonate-independent route from pyruvate and glyceraldehyde 3-phosphate as precursors. Here we describe the cloning from peppermint (Mentha X piperita) and heterologous expression in Escherichia coli of 1-deoxy-D-xylulose-5-phosphate synthase, the enzyme that catalyzes the first reaction of this pyruvate/glyceraldehyde 3-phosphate pathway. This synthase gene contains an ORF of 2,172 base pairs. When the proposed plastid targeting sequence is excluded, the deduced amino acid sequence indicates the peppermint synthase to be about 650 residues in length, corresponding to a native size of roughly 71 kDa. The enzyme appears to represent a novel class of highly conserved transketolases and likely plays a key role in the biosynthesis of plastid-derived isoprenoids essential for growth, development, and defense in plants

Cell walls were isolated from the mesocarp of grape (Vitis vinifera L.) berries at developmental stages from before veraison through to the final ripe berry. Fluorescence and light microscopy of intact berries revealed no measurable change in cell wall thickness as the mesocarp cells expanded in the ripening fruit. Isolated walls were analyzed for their protein contents and amino acid compositions, and for changes in the composition and solubility of constituent polysaccharides during development. Increases in protein content after veraison were accompanied by an approximate 3-fo1d increase in hydroxyproline content. The type I arabinogalactan content of the pectic polysaccharides decreased from approximately 20 mol % of total wall polysaccharides to about 4 mol % of wall polysaccharides during berry development. Galacturonan content increased from 26 to 41 mol % of wall polysaccharides, and the galacturonan appeared to become more soluble as ripening progressed. After an initial decrease in the degree of esterification of pectic polysaccharides, no further changes were observed nor were there large variations in cellulose (30-35 mol % of wall polysaccharides) or xyloglucan (approximately 10 mol % of wall polysaccharides) contents. Overall, the results indicate that no major changes in cell wall polysaccharide composition occurred during softening of ripening grape berries, but that significant modification of specific polysaccharide components were observed, together with large changes in protein composition

▪ Abstract  While the concept of H + -coupling has dominated studies of energy-dependent organic solute transport in plants for over two decades, recent studies have demonstrated the existence of a group of organic solute transporters, belonging to the ATP-binding cassette (ABC) superfamily, that are directly energized by MgATP rather than by a transmembrane H + -electrochemical potential difference. Originally identified in microbial and animal cells, the ABC superfamily is one of the largest and most widespread protein families known. Competent in the transport of a broad range of substances including sugars, peptides, alkaloids, inorganic anions, and lipids, all ABC transporters are constituted of one or two copies each of an integral membrane sector and cytosolically oriented ATP-binding domain. To date, two major subclasses, the multidrug resistance-associated proteins (MRPs) and multidrug resistance proteins (MDRs) (so named because of the phenotypes conferred by their animal prototypes), have been identified molecularly in plants. However, only the MRPs have been defined functionally. This review therefore focuses on the functional capabilities, energetics, organization, and regulation of the plant MRPs. Otherwise known as GS-X pumps, or glutathione-conjugate or multispecific organic anion Mg 2+ -ATPases, the MRPs are considered to participate in the transport of exogenous and endogenous amphipathic anions and glutathionated compounds from the cytosol into the vacuole. Encoded by a multigene family and possessing a unique domain organization, the types of processes that likely converge and depend on plant MRPs include herbicide detoxification, cell pigmentation, the alleviation of oxidative damage, and the storage of antimicrobial compounds. Additional functional capabilities might include channel regulation or activity, and/or the transport of heavy metal chelates. The identification of the MRPs, in particular, and the demonstration of a central role for ABC transporters, in general, in plant function not only provide fresh insights into the molecular basis of energy-dependent solute transport but also offer the prospect for manipulating and investigating many fundamental processes that have hitherto evaded analysis at the transport level.