132 research outputs found

    Identification of new sources of resistance to RHBV- rice hoja blanca virus

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    With the aim to find new sources of resistance to rice hoja blanca (white leaf) disease, transmitted by the insect Tagosodes orizicolus, 660 genotypes were evaluated under greenhouse and field conditions. Seven resistant genotypes were identified, and genomic studies were performed to demonstrate that the resistance in these sources is genetically different from that of Fedearroz 2000, which is currently the variety with the most resistance to hoja blanca. These new resistance sources constitute a resource that can be used to sustainably extend hoja blanca disease management throughout all of the rice-growing regions of tropical America. This is the first report of hoja blanca resistance in indica rice and different from that of Fedearroz 2000

    Selective Synthesis of α-, β-, and γ-Ag2WO4 Polymorphs: Promising Platforms for Photocatalytic and Antibacterial Materials

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    Silver tungstate (Ag2WO4) shows structural polymorphism with different crystalline phases, namely, orthorhombic, hexagonal, and cubic structures that are commonly known as α, β, and γ, respectively. In this work, these Ag2WO4 polymorphs were selectively and successfully synthesized through a simple precipitation route at ambient temperature. The polymorph-controlled synthesis was conducted by means of the volumetric ratios of the silver nitrate/tungstate sodium dehydrate precursors in solution. The structural and electronic properties of the as-synthesized Ag2WO4 polymorphs were investigated by using a combination of X-ray diffraction and Rietveld refinements, X-ray absorption spectroscopy, X-ray absorption near-edge structure spectroscopy, field-emission scanning electron microscopy images, and photoluminescence. To complement and rationalize the experimental results, first-principles calculations, at the density functional theory level, were carried out, leading to an unprecedented glimpse into the atomic-level properties of the morphology and the exposed surfaces of Ag2WO4 polymorphs. Following the analysis of the local coordination of Ag and W cations (clusters) at each exposed surface of the three polymorphs, the structure–property relationship between the morphology and the photocatalytic and antibacterial activities against amiloride degradation under ultraviolet light irradiation and methicillin-resistant Staphylococcus aureus, respectively, was investigated. A possible mechanism of the photocatalytic and antibacterial activity as well the formation process and growth of the polymorphs is also explored and proposed

    Compartmentalization of Immune Response and Microbial Translocation in Decompensated Cirrhosis

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    Background: Acquired dysfunctional immunity in cirrhosis predisposes patients to frequent bacterial infections, especially spontaneous bacterial peritonitis (SBP), leading to systemic inflammation that is associated with poor outcome. But systemic inflammation can also be found in the absence of a confirmed infection. Detection of bacterial DNA has been investigated as a marker of SBP and as a predictor of prognosis. Data is, however, contradictory. Here we investigated whether levels of IL-6 and IL-8 putatively produced by myeloid cells in ascites are associated with systemic inflammation and whether inflammation depends on the presence of specific bacterial DNA. Methods and Materials: We enrolled 33 patients with decompensated liver cirrhosis from whom we collected paired samples of blood and ascites. IL-6 and IL-8 were measured in serum samples of all patients using ELISA. In a subset of 10 representative patients, bacterial DNA was extracted from ascites and whole blood, followed by 16S rRNA gene amplicon sequencing. Results: There were significantly higher levels of IL-6 in ascites fluid compared to blood samples in all patients. Interestingly, IL-6 levels in blood correlated tightly with disease severity and surrogates of systemic inflammation, while IL-6 levels in ascites did not. Moreover, patients with higher blood CRP levels showed greater SBP prevalence compared to patients with lower levels, despite similar positive culture results. Bacterial richness was also significantly higher in ascites compared to the corresponding patient blood. We identified differences in microbial composition and diversity between ascites and blood, but no tight relationship with surrogates of systemic inflammation could be observed. Discussion: In decompensated cirrhosis, markers of systemic inflammation and microbiota composition seem to be dysregulated in ascites and blood. While a relationship between systemic inflammation and microbiota composition seems to exist in blood, this is not the case for ascites in our hands. These data may suggest compartmentalization of the immune response and interaction of the latter with the microbiota especially in the blood compartment

    Thermal-induced conformational changes in the product release area drive the enzymatic activity of xylanases 10B: Crystal structure, conformational stability and functional characterization of the xylanase 10B from Thermotoga petrophila RKU-1

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    AbstractEndo-xylanases play a key role in the depolymerization of xylan and recently, they have attracted much attention owing to their potential applications on biofuels and paper industries. In this work, we have investigated the molecular basis for the action mode of xylanases 10B at high temperatures using biochemical, biophysical and crystallographic methods. The crystal structure of xylanase 10B from hyperthermophilic bacterium Thermotoga petrophila RKU-1 (TpXyl10B) has been solved in the native state and in complex with xylobiose. The complex crystal structure showed a classical binding mode shared among other xylanases, which encompasses the −1 and −2 subsites. Interestingly, TpXyl10B displayed a temperature-dependent action mode producing xylobiose and xylotriose at 20°C, and exclusively xylobiose at 90°C as assessed by capillary zone electrophoresis. Moreover, circular dichroism spectroscopy suggested a coupling effect of temperature-induced structural changes with this particular enzymatic behavior. Molecular dynamics simulations supported the CD analysis suggesting that an open conformational state adopted by the catalytic loop (Trp297-Lys326) provokes significant modifications in the product release area (+1,+2 and +3 subsites), which drives the enzymatic activity to the specific release of xylobiose at high temperatures

    Repercusión de la obesidad en la vida sexual de mujeres adultas en américa, 2010-2021

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    Objetivo: Conocer la repercusión de la obesidad en la vida sexual de mujeres adultas de América entre los años 2010 y 2021. Metodología: Revisión bibliográfica tipo narrativa. Se realizó una búsqueda de artículos en las bases de datos EBSCO, Lilacs, Science Direct, Scielo, Web of Science y Pubmed con los siguientes términos de búsqueda Decs: “Obesidad”, “Salud Sexual”, “Femenina”, “Patología”, “Desarrollo Psicosexual” y los términos Mesh: “Disfunción sexual”, “Psicológica”, “Mujeres” y “Conducta sexual” y sus equivalentes en inglés. Resultados: Entre un 10% y un 60% de mujeres obesas presentan disfunciones sexuales, principalmente falta de deseo, excitación y dificultad para alcanzar el orgasmo, desencadenando inactividad e insatisfacción sexual. Existe una relación entre la obesidad y la insatisfacción con la imagen corporal y la baja autoestima, lo que ocasiona cuadros como depresión, angustia, estrés, ansiedad por el desempeño sexual y pensamientos negativos. La autoimagen negativa también se relaciona con la poca participación que tienen en los encuentros sexuales, lo que les provoca una desconexión con su cuerpo que no les permite reconocer sus necesidades emocionales ni sexuales. Conclusión: La vida sexual de las mujeres obesas es un reto a investigar, ya que sus problemas involucran la dimensión biopsicosocial cuyo abordaje debe ser multidisciplinario. Importante: Estudio derivado de proceso de tesina de pregrado. Las autoras declaran no tener conflicto de intereses.Objective of this study is to publicize the impact of obesity on the sex life of adult women in the Americas between 2010-2021. Methodology: Bibliographic review, an article search was performed in the following databases: EBSCO, Lilacs, Science Direct, Scielo, Web of Science and Pubmed with search terms Decs: Obesity, Sexual health, Female, Pathology, Psychosexual Development, and the next terms “Mesh”: Sexual dysfunction, Psychological, Women and Sexual behavior. Results: Between 10% and 60% of obese women have sexual dysfunctions, the main ones are lack of desire, excitement and difficulty reaching orgasm, triggering inactivity and sexual dissatisfaction. There is also a relationship between obesity, dissatisfaction with body image and low self-esteem; as a result, pictures such as depression, anguish, stress, anxiety about sexual performance are triggered, which causes negative thoughts. Negative self-image is also related to the little participation they have in sexual encounters, causing a disconnection with their body which does not allow them to recognize their emotional or sexual needs. Conclusion: The sex life of obese women provides a challenge to investigate, since it involves the entire biopsychosocial dimension of the human being is involved. It is important that the approach of these users is multidisciplinary

    The activity of methylene blue against asexual and sexual stages of Plasmodium vivax

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    Methylene blue (MB) is an alternative for combating drug-resistant malaria parasites. Its transmission-blocking potential has been demonstrated in vivo in murine models, in vitro, and in clinical trials. MB shows high efficacy against Plasmodium vivax asexual stages; however, its efficacy in sexual stages is unknown. In this study, we evaluated the potential of MB against asexual and sexual forms of P. vivax isolated from the blood of patients residing in the Brazilian Amazon. An ex vivo schizont maturation assay, zygote to ookinete transformation assay, direct membrane feed assay (DMFA), and standard membrane feed assay (SMFA) using P. vivax gametocytes with MB exposure were performed. A cytotoxicity assay was also performed on freshly collected peripheral blood mononuclear cells (PBMCs) and the hepatocyte carcinoma cell line HepG2. MB inhibited the P. vivax schizont maturation and demonstrated an IC50 lower than that of chloroquine (control drug). In the sexual forms, the MB demonstrated a high level of inhibition in the transformation of the zygotes into ookinetes. In the DMFA, MB did not considerably affect the infection rate and showed low inhibition, but it demonstrated a slight decrease in the infection intensity in all tested concentrations. In contrast, in the SMFA, MB was able to completely block the transmission at the highest concentration (20 µM). MB demonstrated low cytotoxicity to fresh PBMCs but demonstrated higher cytotoxicity to the hepatocyte carcinoma cell line HepG2. These results show that MB may be a potential drug for vivax malaria treatment
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