Evaluación de la actividad antioxidante para el aprovechamiento del muérdago que infesta la zona chinampera de Xochimilco

El muérdago es una planta parásita que se desarrolla en las ramas de árboles y arbustos. Produce un órgano llamado haustorio para tomar agua y sales minerales, ocasionando graves daños al hospedero afectando su desarrollo hasta causarle la muerte. A la fecha, no existe un estudio bioquímico amplio de muérdagos mexicanos lo que podría promover su control y aprovechamiento. Por lo que el objetivo de este trabajo fue evaluar la actividad antioxidante in vitro e in vivo de extractos de hojas, frutos y tallos del muérdago Cladocolea (C) loniceroides (van Tieghem) Kuijt, recolectado en la zona chinampera de Xochimilco, así como observar la actividad citotóxica in vitro en cultivo de células de cáncer de mama. Adicionalmente, este estudio será útil para darle un valor agregado y contribuir al conocimiento científico de esta planta. El análisis químico proximal de hojas, tallos y frutos mostró que el tallo contiene el mayor contenido de fibra cruda (14.80 ± 0.77%) de la planta; la hoja el mayor contenido de proteína cruda y de carbohidratos (19.08 ± 0.59 % y 71.07%, respectivamente) y el fruto el mayor contenido de extracto etéreo (28.4 ± 1.90%). El fruto forma una sustancia viscosa que es soluble en éter etílico lo que eleva la concentración del extracto etéreo del análisis químico. La mayor concentración de polifenoles extraídos de hoja y tallo se obtuvo por extracción acuosa durante 5 min en ebullición. Sin embargo en el caso del fruto la extracción se realizó usando metanol con agitación constante durante 2 h a temperatura ambiente. También se realizó una saponificación previa a la extracción de polifenoles, pero en todos los casos el rendimiento fue menor que cuando no se saponificó. Comparativamente el contenido de polifenoles totales expresado como mg equivalentes de ácido gálico (AG) de las diferentes secciones de la planta resultó: fruto>hoja>tallo:189.5 ± 4.9; 93.33± 0.94 y 74.53 ± 0.95, respectivamente. Se observó que los flavonoides no son los principales componentes de los extractos, lo cual sugiere que es necesario caracterizar con mayor precisión la naturaleza de éstos compuestos. Se estudió el comportamiento de los extractos obtenidos en diferentes sistemas de óxido-reducción para la evaluación de la actividad antioxidante. Se observó que el extracto metanólico del tallo presentó la mayor capacidad de reducción del radical 2,2-difenol-1-picrilhidrazil (DPPH• ), expresada como % Inhibición = 90.27 ± 0.127%. Sin embargo, el extracto acuoso del tallo presentó el menor IC50 (0.065 mg eq. Trolox/g), lo que indicó que una pequeña concentración de extracto es capaz de reducir al radical DPPH● eficientemente. La capacidad reductora del extracto acuoso del tallo en el sistema ABTS/lacasa (Deni Lite IIS) fue de 39.84 ± 0.4 mg eq. AG/g; mientras que cuando se utilizó lacasa de Rhus vernicifera fue en el extracto metanólico del fruto (40.22 ± 3.21 mg eq. AG/g) en donde se obtuvo la mayor actividad antioxidante. Todas los extractos, sin excepción, presentaron poder reductor en un sistema de óxidoreducción en el que se tomó como referencia al glutatión reducido (GSH). En particular los extractos metanólicos y por saponificación presentaron un poder reductor superior al del GSH en el mismo sistema; mientras que los extractos acuosos tuvieron un menor poder reductor que el GSH. Asimismo, todos los extractos presentaron actividad quelante ante el Fe²⁺ en un sistema in vitro, excepto el extracto obtenido por saponificación del fruto, en donde esta actividad fue nula. De la misma manera el extracto acuoso del fruto de muérdago administrado en ratas, a las que previamente se les indujo lipoperoxidación con Fe²⁺ , inhibió el deterioro de los lípidos, ya que no hubo diferencia significativa (p˂ 0.005) entre las ratas de prueba y el grupo control debido a la capacidad que tienen los polifenoles de quelar metales. En todos los extractos de muérdago se cuantificó nitrógeno total por el método de Kjeldahl y proteína verdadera por el método del colorante ligado a la proteína. Sin embargo cuando los extractos se analizaron por electroforesis no se observó la presencia de bandas de proteína. Esto resultó diferente a lo reportado para Viscum (V.) album en el que se han detectado lectinas y viscotoxinas peptídicas. Lo anterior hace pensar que los compuestos antioxidantes de los extractos estudiados son polifenoles, algunos de ellos nitrogenados y/o compuestos no polifenólicos nitrogenados. En este estudio el contenido de polifenoles del fruto de C. loniceroides observado fue 8 veces mayor que el reportado para V. album y al aplicarse a la línea celular ZR-75 de cáncer de mama ductal se observó de forma preliminar que tiene un efecto citotóxico con una CL50 entre 0.01 y 0.1 mg eq. AG/mL de medio de cultivo, a diferencia de V. album que debe su actividad citotóxica a la presencia de lectinas y viscotoxinas y no a los polifenoles. El muérdago que infesta a la zona chinampera de Xochimilco fue clasificado como Cladocolea loniceroides, una especie endémica de la región, considerada inútil hasta antes de esta investigación. Sin embargo, las pruebas realizadas a las hojas, tallo y frutos demostraron que contienen polifenoles de diversa naturaleza química, lo cual le confiere una gran actividad antioxidante. Pruebas in vivo, utilizando ratas como modelo experimental, mostraron que la actividad antioxidante inhibe la lipoperoxidación. Por otro lado, un extracto acuoso del fruto fue capaz de inhibir el desarrollo de un cultivo de células cancerosas de mama; lo cual indicaría que éste podría utilizarse para la obtención de un extracto estandarizado que contribuya a la prevención y tratamiento de dicho cáncer.Mistletoe is a parasitic plant which grows attached to and within the branches of trees and shrubs. It also produces a haustorium which grows in the host, mostly downwards, towards the source of water and mineral nutrients. The growth of the mistletoe haustorium restricts nutrient flow further along the host branch. Mistletoe impact is rather negative causing great tree mortality. To date there is not any research on Mexican mistletoes, which may promote their control and usefulness. Thus, the aim of the study was to investigate both in vitro and in vivo antioxidant activity of Cladocolea (C.) loniceroides (van Tieghem) Kuijt extract, as obtained of leaves, stems or fruits collected at the Xochimilco Lake so as to observe the in vitro cytotoxic activity against breast cancer cells. Additionally, this knowledge would be used to obtain an added-value product in the near future. The chemical proximal analysis of leaves, stem and fruits showed that the stem affords the plant’s highest crude fiber content (14.80 ± 0.77%); the leaves had the highest both crude protein and carbohydrates content (19.08 ± 0.59% and 71.07%, respectively), and the fruits registered the highest ether extract content (28.4 ± 1.90%). It was also observed that the fruits exude a viscous substance, which is ethyl ether soluble, increasing the ether extract content. A boiling aqueous extraction of leaves and stem for 5 min afforded the highest polyphenols content. However, the polyphenols extraction from the fruits was carried out using metanol by shaking for 2 h at room temperature. The saponification reaction was also used in order to extract polyphenolics, but a further extraction of such compounds was poor. Leaves, stem and fruits extracts were assayed to assess total polyphenolics expressed in gallic acid equivalents (AGE; mg per g dry matter) as follows: fruits>leaves>stem: 189.5 ± 4.9; 93.33± 0.94 and 74.53 ± 0.95, respectively). Flavonoids did not occur as the main extract polyphenolics, for this reason it should be necessary to perform a detailed chemical analysis of these compounds to elucidate the nature of all of them. Regarding the behavior of the different extracts, this was assayed through different oxide-reduction systems in order to assess the antioxidant activity. It was observed that the stem methanolic extract showed the highest inhibition activity of formation of the radical 1,1-diphenyl-2-picrylhydrazyl (DPPH• ), which was assessed as 90.27 ± 0.127%. On the other hand the stem aqueous extraction observed the lowest IC50 value (0.065 mg eq. Trolox/g), which means that a low polyphenolics concentration is able to scavenge DPPH● efficiently. The stem aqueous extract registered the highest antioxidant activity measured by ABTS/laccase of Deni Lite IIS (39.84 ± 0.4 mg eq. AG/g) and fruit methanolic extract by ABTS/ laccase of Rhus vernicifera (40.22 ± 3.21 mg eq. AG/g). When the reducing power of all extracts was assessed, it was observed that these showed such activity in comparison to that of reduced glutathione (GSH), which was used as a control into the oxide-reducing system. Particularly, methanolic and saponificated extracts showed a reducing power higher than that of GSH; while the aqueous extracts observed lower reducing power than that of GSH. Similarly all extracts showed in vitro Fe²⁺ chelating activity, except the fruits saponificated extract, in which no activity was detected. When the chelating activity of a fruits aqueous extract was assessed in vivo by using rats with Fe²⁺ induced lipoperoxidation this extract inhibited lipids oxidation because there were no significant differences (p˂ 0.005) when compared to the rat control group. This is possible because polyphenols are metal chelators. Crude protein and true protein content in all extracts were assessed by both Kjeldahl and the dye-binding methods, respectively. However when the same extracts were analyzed by the electrophoresis method, no protein band was observed. This finding is different to that registered in Viscum (V.) album extracts, in which lectins and viscotoxins have been detected. Thus it may be inferred that the antioxidant compounds are polyphenols, some of them containing nitrogen and others do not. In this study the C. loniceroides fruits polyphenols content was 8 times higher than that reported for V. album, so when an aqueous extract of the fruits was assayed on ZR75 breast cancer cells, it was observed that, in a preliminary test, it showed a citotoxic effect (LC₅₀= 0.01 to 0.1 mg GAE/mL). This finding is different if compared to V. album extract because its citotoxic activity is linked to both lectins and viscotoxins as opposed to polyphenols. Mistletoe had been deemed as a useless plant prior to this research. However, several trials carried out using the leaves, stem and fruits showed that these parts afforded different polyphenols, which makes it an excellent natural antioxidant resource. Furthermore, several in vivo assays using rats showed that the antioxidant activity inhibits lipoperoxidation because of polyphenols ability to chelate Fe²⁺. Additionally, an aqueous extract of the fruits was able to reduce the growth of ZR75 breast cancer cells, which may lead to obtain a standardized extract that might be used in the prevention and treatment of such cancer

Transforming the news value chain in the social era: a technical perspective

Purpose: This paper develops a conceptual framework to unde rstand the influence that the social era is having on the value chain of the local news industry. We theoretically advance value chain theory by firstly, considering the influence of community type and age on consumption and secondly exploring the role that consumers can play in value adding activities. Our theoretical contribution lies in moving from a transactional approach towards consumer relationships in the value chain towards managing consumers as a source of relational value (e.g. co-creation and integrated perspectives). Design: The conceptual framework is theoretically positioned in relation to community and digital community practices in the social era. A series of research questions are presented, then these questions are explored drawing on empirical data from the PEW database. We then advance the framework further to consider news firm strategy towards its consumers. 15 in-depth executive interviews were conducted with local news organizations in the Manchester area of the UK. Findings: We illustrate that different types of communities (merging cohorts and locations) are influencing levels of technological and social connectivity within the value chain. We also find that the news industry is experimenting with reconfiguring its consumer relations from a purely transactional to a co-created and participatory value added activity in the social era. In terms of its policy impact our findings show that the whole strategic value chain ideology of the news industry needs to change radically; away from its largely transactional (and lack of trust) approach in the ability of consumers to create value in the supply chain (other than to buy a product) and, move towards much greater consumer involvement and participation in value chain processes (creation, production and distribution of news products and services). Originality/value: The change associated with social media and connec tivity is changing the way that different community types and consumer groups are now consuming and participating in news content creation. Unlike previous studies we show that there is variance and complexity in the levels of consumer participation by community type/age group. Using the PEW data we contribute to knowledge on the value creation strategy of news firms in the social era, by identifying how communicative, social and communicative logics influence value and co-creation activities in the local news supply chain. Through our interviews we advance value co-creation theory from its strategic and marketing origins to operational and supply chain implementation

Global stability map of the flow in a horizontal concentric cylinder forced by natural convection.

There are a large number of studies in the literature on natural convection in the annulus between horizontal concentric cylinders. However, not many publications dealing with global stability analysis in this kind of flow have been published. For a fixed diameter ratio L/Di = (Ro − Ri)/2Ri, being Ri and Ro the inner and outer cylinder radii respectively, and assuming Boussinesq approximation, the solution only depends on Prandtl (P r ≡ ν/α) and Rayleigh (Ra ≡ g β L3 (Ti − To)/(ν α)) numbers. A spectral collocation code has been developed to solve the problem by means of Chebyshev and Fourier differentiation matrices for L/Di = 0.8 and it has been validated with classical experimental results. Steady solutions have been sought within the range P r ∈ [1e−2, 1] and Ra ∈ [1e-2, 5e6]. As a result, a steady solution Pr-Ra map (consisting of 149 x 75 points) has been traced, where the different families of similar solutions found are detailed, mainly characterized by presenting single or multiple plumes. In addition, two main double-solution regions have been found

Evaluation of metabolism and biosignaling in the angiogenic microenvironment as potential targets for therapeutic intervention

The "re-discovery" of Warburg effect at the turn of the present millennium has been a key determinant of the current renewed interest on cancer metabolism. In fact, metabolic reprogramming has been identified as one of the hallmarks of cancer. However, cancers grow in tight contact with non-tumoral accompanying cells and the surrounding extracellular matrix, as underlined by the concept of tumor microenvironment. Endothelial cells are key components of this tumor microenvironment, since they are requested for angiogenesis, another hallmark of cancer. In this complex system, rewiring of metabolism and signaling pathway in cancer, endothelial and other accompanying cell emerges as new potential targets for therapeutic intervention. In this communication, we will present the drug discovery and characterization approach of our group and our more recent results in this field, including new modeling with an evolutionary and ecological point of view.[Our experimental work is supported by grants BIO2014-56092-R (MINECO and FEDER) and P12-CTS-1507 (Andalusian Government and FEDER) and funds from group BIO-267 (Andalusian Government). The "CIBER de Enfermedades Raras" is an initiative from the ISCIII (Spain)]. This communication has the support of a travel grant "Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech"

Recommender system to identify students with learning deficiencies in assessments

[EN] Find areas and indicators of achievement where students need to reinforce their knowledge is a difficult task for teachers in schools. This article presents a decision-making support system that allows teachers to identify students with poor academic performance. The strategy is a Matrix Based Recommender System to rate assessments and share the results using statistical graphs. To validate this proposal we used focus group and daily meetings methodologies. The proposed strategy was tested in UGEL07-Lima-Perú with 135 schools and 25491 students in evaluation process. The evaluation results show that teachers agree with the proposed strategy, because it allows them to have assessment information everywhere and at every time. The results also highlight that using the tool users can have visual information in real time. Furthermore, the information shared through the application improves decision-making on corrective actions for poor academic performance in evaluated areas

The IgA Isotype of Anti-β2 Glycoprotein I Antibodies Recognizes Epitopes in Domains 3, 4, and 5 That Are Located in a Lateral Zone of the Molecule (L-Shaped)

Background: Antiphospholipid syndrome (APS) is characterized by thrombosis and/or pregnancy morbidity with presence of anti-phospholipid antibodies (aPL). The APS classification criteria only consider the aPL of IgG/IgM isotype, however testing of aPL of IgA isotype is recommended when APS is suspected and consensus aPL are negative. IgA anti-βeta-2 glycoprotein-I (B2GP1) has been clearly related with occurrence of thrombotic events. Antibodies anti-B2GP1 of IgG/M isotypes recognize an epitope in Domain 1 (R39-G43), the epitopes that recognize IgA anti-B2GP1 antibodies are not well-identified.Aim: To determine the zones of B2GP1 recognized by antibodies of IgA isotype from patients with APS symptomatology and positive for IgA anti-B2GP1.Methods: IgA antibodies to Domain-1(D1) and Domain-4/5(D4/5) of B2GP1 (ELISA) and epitope mapping on oligopeptide arrays of B2GP1 were evaluated in sera from a group of 93 patients with at least one thrombotic and with isolated positivity for IgA anti-B2GP1 antibodies (negative for other aPL).Results: A total of 47 patients (50.5%) were positive for anti-D4/5 and 23(25%) were positive for anti-D1. When peptide arrays were analyzed, three zones of B2GP1 reactivity were identified for more than 50% of patients. The center of these zones corresponds to amino acids 140(D3), 204(D4), and 264(D5). The peptides recognized on D3 and D4 contain amino acid sequences sharing high homology with proteins of microorganism that were previously related with a possible APS infectious etiology. In the three-dimensional structure of B2GP1, the three peptides, as the R39-G43 epitope, are located on the right side of the molecule (L-shape). The left side (J-shape) does not bind the antibodies.Conclusions: Patients with thrombotic APS clinical-criteria, and isolated IgA anti-B2GP1 positivity appear to preferentially bind, not to the D1 or D4/5 domains of B2GP1, but rather to three sites in D3, D4, and D5. The sites on D3 and D4 were previously described as the target identified by human monoclonal antibodies derived from patients that were capable of inducing APS in animal models. The localization of these epitopes opens a new route to explore to increase understanding of the patholophysiology of the APS and to propose new alternatives and therapeutic targets

Sensitivity of bile acid transport by organic anion-transporting polypeptides to intracellular pH

AbstractWe investigated the influence of intracellular pH (pHi) on [14C]-glycocholate (GC) uptake by human hepatoblastoma HepG2 cells that express sodium-independent (mainly OATP-A and OATP-8), but not sodium-dependent, GC transporters. Replacement of extracellular sodium by choline (Chol) stimulated GC uptake but did not affect GC efflux from loaded cells. Amiloride or NaCl replacement by tetraethylammonium chloride (TeACl) or sucrose also increased GC uptake. All stimulating circumstances decreased pHi. By contrast, adding to the medium ammonium or imidazole, which increased pHi, had no effect on GC uptake. In Chinese hamster ovary (CHO) cells expressing rat Oatp1, acidification of pHi had the opposite effect on GC uptake, that is, this was reduced. Changes in extracellular pH (pHo) between 7.40 and 7.00 had no effect on GC uptake at pHi 7.30 or 7.45 when pHo<pHi. However, GC uptake was inhibited at pHo 7.40 and 7.80 when pHo>pHi. Inhibition was not proportional to the pHo−pHi difference. Intracellular acidification decreased Vmax, but had no effect on Km. In sum, sodium-independent GC transport can be affected by intracellular acidification, possibly due both to modifications in the driving forces and to the particular response to protonation of carrier proteins involved in this process

Manual Técnico

La investigación tiene como propósito desarrollar un software capaz de realizar los diversos cálculos eléctricos y mecánicos de línea eléctrica de media y baja tensión hasta un nivel de tensión de 34.500 Voltios, para la empresa Megaelectric ubicada en la ciudad de Santa Marta. Hoy en día el recurso más valioso que se tiene es el tiempo, ningún otro puede competir con este intangible. Su uso, manejo y administración, combinada con el conocimiento oportuno de la información proporciona el éxito a una empresa en particular, es por esta razón que las compañías desarrollan técnicas por medio de las cuales están en capacidad para competir en el mercado laboral. Existen diferentes aplicaciones que facilitan la ejecución de las tareas de cálculo en las diferentes ramas de la ingeniería, disminuyendo, con ello el riesgo de error, ya sea por enajenación o simplemente por lo complejo y/o extenso de las operaciones, errores que pueden resultar en mayores costos de producción, o en fallas de diseño que puedan poner en riesgo la estabilidad de un proyecto, o en el peor de los casos vidas humanas