1,885 research outputs found

    Vaccines against malaria

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    There is no licenced vaccine against any human parasitic disease and Plasmodium falciparum malaria, a major cause of infectious mortality, presents a great challenge to vaccine developers. This has led to the assessment of a wide variety of approaches to malaria vaccine design and development, assisted by the availability of a safe challenge model for small-scale efficacy testing of vaccine candidates. Malaria vaccine development has been at the forefront of assessing many new vaccine technologies including novel adjuvants, vectored prime-boost regimes and the concept of community vaccination to block malaria transmission. Most current vaccine candidates target a single stage of the parasite's life cycle and vaccines against the early pre-erythrocytic stages have shown most success. A protein in adjuvant vaccine, working through antibodies against sporozoites, and viral vector vaccines targeting the intracellular liver-stage parasite with cellular immunity show partial efficacy in humans, and the anti-sporozoite vaccine is currently in phase III trials. However, a more effective malaria vaccine suitable for widespread cost-effective deployment is likely to require a multi-component vaccine targeting more than one life cycle stage. The most attractive near-term approach to develop such a product is to combine existing partially effective pre-erythrocytic vaccine candidates

    Condition-dependent male copulatory courtship and its benefits for females

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    Postcopulatory sexual selection has shaped the ornaments used during copulatory courtship. However, we know relatively little about whether these courtship ornaments are costly to produce or whether they provide indirect benefits to females. We used the mealworm beetle, Tenebrio molitor, to explore this. We challenged males using an entomopathogenic fungus and compared their courtship (frequency of leg and antennal contacts to the female), copulation duration, number of eggs laid, and hatching rate against control males. Infected males copulated for longer yet they reduced their leg and antennal contacts compared to control males. However, there was no obvious relation between infection, copulation duration, and courtship with egg production and hatching success. In general, our results indicate that the ornaments used during postcopulatory courtship are condition-dependent. Moreover, such condition dependence cannot be linked to male fitness.Fil: Cargnelutti, Franco Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Reyes Ramírez, Alicia. Universidad Nacional Autónoma de México; MéxicoFil: Cristancho, Shara. Universidad El Bosque; ColombiaFil: Sandoval García, Iván A.. Universidad Nacional Autónoma de México; MéxicoFil: Rocha Ortega, Maya. Universidad Nacional Autónoma de México; MéxicoFil: Calbacho Rosa, Lucía Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Palacino, Freddy. Universidad El Bosque; ColombiaFil: Córdoba Aguilar, Alex. Universidad Nacional Autónoma de México; Méxic

    Prácticas utilizadas para la producción y mejora de la productividad de un módulo agroforestal

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    Objective: To evaluate the practices to agricultural production and productivity improvement. Design/methodology/approach: A comparatively analysis of practices performed by land producer in an agroforestry module was carried out. As well as the yield obtained in two-year period, both from the economic income point of view and diversification of plant species that were established. Results: The practices used in the module were: a) conservation (reduced tillage), b) vegetative (crop diversification, associated crops, intercropping and crop rotation) and c) agronomic (bottom fertilization and fertigation). During this study (2015-2018), 16 plant species were established. Yields and income from the sale of surplus production increased over time, which contributed to the food security and economy of the rural family. Limitations on study/implications: The present work, did not evaluate the biological efficiency of the crop association in the agroforestry module, which could give an additional value to this type of production versus monoculture systems. Findings/conclusions: The type of practices used in the production of food and fodder in an agroforestry module was documented. The production of crops in small areas, under the agroforestry approach, can represent a sustainable alternative of agricultural production for the arid and semi-arid regions and a mean to improve income and nutrition of the rural family.Objetivo. Determinar las prácticas utilizadas para la producción agrícola y mejora de la productividad de en un módulo agroforestal. Diseño/metodología/aproximación. Se realizó el análisis comparativo de las prácticas que el productor realiza en un módulo agroforestal, así como del rendimiento obtenido en dos años, desde el punto de vista económico y de diversificación de especies vegetales que fueron establecidas. Resultados. Las prácticas utilizadas en el módulo fueron: a) conservación (labranza reducida); b) vegetativas (diversificación de cultivos, cultivos asociados, cultivos intercalados y rotación de cultivos); y c) agronómicas (fertilización de fondo y fertigación). Durante el periodo evaluado (2015-2018) se establecieron 16 especies vegetales. Los rendimientos e ingresos por venta de excedentes de la producción se incrementaron con el tiempo. Lo cual contribuyó en la seguridad alimentaria y economía de la familia rural. Limitaciones del estudio/implicaciones. En el presente trabajo, la eficiencia biológica de la asociación en el módulo agroforestal no fue evaluada. Dicha eficiencia podría dar un valor adicional a este tipo de producción versus los sistemas de monocultivo. Hallazgos/conclusiones. Se documentaron el tipo de prácticas utilizadas en la producción de alimentos y forraje en un módulo agroforestal. La producción de cultivos en pequeñas superficies, bajo el enfoque agroforestal, es una alternativa sustentable de producción agrícola para las regiones áridas y semiáridas, asimismo es un medio para mejorar el ingreso y nutrición de la familia rural

    Transcriptome analyses throughout chili pepper fruit development reveal novel insights into the domestication process

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    Chili pepper (Capsicum spp.) is an important crop, as well as a model for fruit development studies and domestication. Here, we performed a time-course experiment to estimate standardized gene expression profiles with respect to fruit development for six domesticated and four wild chili pepper ancestors. We sampled the transcriptomes every 10 days from flowering to fruit maturity, and found that the mean standardized expression profiles for domesticated and wild accessions significantly differed. The mean standardized expression was higher and peaked earlier for domesticated vs. wild genotypes, particularly for genes involved in the cell cycle that ultimately control fruit size. We postulate that these gene expression changes are driven by selection pressures during domestication and show a robust network of cell cycle genes with a time shift in expression, which explains some of the differences between domesticated and wild phenotypes

    Productividad y sostenibilidad del sorgo (Sorghum bicolor L.) en el trópico seco de Puebla, México

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    La baja tasa de la productividad que enfrentan los productores de sorgo (Sorghum bicolor L.) en el trópico seco de Puebla, México, particularmente, en la región de la Mixteca Baja, es multifactorial, lo que ocasiona bajos ingresos
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