Biotecnología: una ciencia moderna para una institución centenaria

Biotecnología es “toda aplicación tecnológica que utilice sistemas biológicos y organismos vivos o sus derivados para la creación o modificación de productos o procesos para usos específicos” (Convenio sobre Diversidad Biológica de la Naciones Unidas, 1992). La Biotecnología moderna está basada en la estructura de la molécula de ADN (Watson y Crick, 1953) y el descubrimiento de las enzimas de restricción y de las técnicas de transformación celular. El primer ejemplo exitoso de la aplicación de estos conocimientos ocurrió en 1978, cuando se consiguió producir insulina humana en una bacteria transgénica. En esta conferencia, se presenta una puesta al día del conocimiento biotecnológico, desde el primer animal transgénico (un ratón, 1982) y la clonación de Dolly (una oveja, 1997) hasta la Biotecnología Vegetal, considerada una esperanza de futuro, y los últimos avances como la síntesis de vida en el laboratorio y las células madre inducidas. El alcance de estos avances es impredecible, pero demuestran que se trata de una poderosa tecnología y que un diálogo profundo es necesario.Biotechnology is “any technological application that uses biological systems, living organisms, or derivatives thereof, to make or modify products or processes for specific use” (United Nations Convention on Biological Diversity, 1992). Modern Biotechnology is based on the duplex helix structure of the DNA molecule, the discovery of restriction enzymes and the cell transformation techniques. The first example of a successful application of this knowledge occurred in 1978, when human insulin was produced by a transgenic bacterium. In this lecture, an update of biotechnological knowledge is presented, from the first transgenic animal (a mouse, 1982) and the cloning of Dolly (a sheep, 1997) to the Plant Biotechnology, considered a hope for the future, and the last advances such as synthesis of life in the lab and the induced pluripotent stem cells. The implications of these advances are unpredictable, but they demonstrate that is a powerful technology and that a deep dialogue is necessar

El debate sobre cultivos transgénicos: impacto ambiental y seguridad alimentaria mundial

Numerosos estudios independientes muestran que los cultivos y alimentos transgénicos son seguros para el consumidor y el medio ambiente; hay otros estudios que muestran que los cultivos GM son beneficiosos en términos de mayor rendimiento y ahorro de costes en la producción agrícola. Sin embargo, el debate sobre los riesgos potenciales de los cultivos y alimentos transgénicos continúa. En este trabajo se revisan los puntos de controversia con respecto al medio ambiente y a una alimentación suficiente para el mundo. El sorprendente hallazgo de que la batata es un transgénico natural que fue modificado por una bacteria del suelo hace miles de años puede influir en la percepción pública sobre la seguridad de los alimentos transgénicos. Los cultivos transgénicos han sido adoptados a ritmos sin precedentes desde su introducción comercial en 1996, alcanzando los 181,5 millones de hectáreas en 2014, cultivados en 28 países biotecs y por 18 millones de agricultores, en su mayoría pequeños agricultores de países en vías de desarrollo. Los cultivos transgénicos no son una panacea pero tienen un enorme potencial y pueden hacer una gran contribución a la reducción de la pobreza optimizando la productividad de los cultivosNumerous independent, scientific studies show that GM crops and foods are safe for the consumer and the environment; there are other studies showing that GM crops are beneficial in terms of higher yields and cost savings in agricultural production. However, the debate about the potential risks of GM crops and foods continues. In this paper the controversial points with respect to the environment and sufficient food for the world are reviewed. The surprising finding that sweet potato is a natural GM plant modified by a soil bacterium thousands of years ago can influence public perceptions about safety of GM foods. GM crops have been adopted at unprecedented rates since their commercial introduction in 1996, reaching 181,5 million hectares in 2014, on 28 biotech countries and by 18 million farmers, most of them smallholders in developing countries. GM crops are not a panacea but have an enormous potential and can make a major contribution to poverty reduction by optimizing crop productivit

Spectrophotometric Quantitation of Antioxidant Capacity through the Formation of a Phosphomolybdenum Complex: Specific Application to the Determination of Vitamin E1

A spectrophotometric method has been developed for the quantitative determination of antioxidant capacity. The assay is based on the reduction of Mo(VI)to Mo(V) by the sample analyte and the subsequent formation of a green phosphate/Mo(V) complex atacidic pH. The method has been optimized and characterized with respect to linearity interval, repetitivity and reproducibility, and molar absorption coefficients for the quantitation of several antioxidants, including vitamin E. The phosphomolybdenum method, in combination with hexane monophasic extraction, has also been adapted for the specific determination of vitamin E in seeds. The results obtained with the proposed method were validated by comparison with a standard HPLC method. The phosphomolybdenum method is routinely applied in our laboratory to evaluate the total antioxidant capacity of plant extracts and to determine vitamin E in a variety of grains and seeds, including corn and soybean

Differential Regulation of Drought Responses in Two Phaseolus vulgaris Genotypes

Drought is probably the most harmful stress affecting common bean crops. Domestication, worldwide spread and local farming practices has entailed the development of a wide variety of common bean genotypes with different degrees of resistance to water stress. In this work, physiological and molecular responses to water stress have been compared in two common bean accessions, PHA-0683 and PMB-0220, previously identified as highly and moderately resistant to water stress, respectively. Our hypothesis was that only quantitative differences in the expression patterns of key genes should be found if molecular mechanisms regulating drought resistance are similar in the two accessions. However, results presented here indicate that the resistance to drought in PMB-0220 and PHA-0683 common bean accessions is regulated by different molecular mechanisms. Differential regulation of ABA synthesis and ABA signaling related genes among the two genotypes, and the control of the drought-induced senescence have a relevant contribution to the higher resistance level of PHA-0683 accession. Our results also suggest that expression patterns of key senescence-related transcription factors could be considered in the screening for drought resistance in common bean germplasm collections

Transcriptomic Response to Water Deficit Reveals a Crucial Role of Phosphate Acquisition in a Drought-Tolerant Common Bean Landrace

Drought is one of the most critical factors limiting legume crop productivity. Understanding the molecular mechanisms of drought tolerance in the common bean is required to improve the yields of this important crop under adverse conditions. In this work, RNA-seq analysis was performed to compare the transcriptome profiles of drought-stressed and well-irrigated plants of a previously characterized drought-tolerant common bean landrace. The analysis revealed responses related with the abscisic acid signaling, including downregulation of a phosphatase 2C (PP2C) and an abscisic acid-8`hydroxylase, and upregulation of several key transcription factors and genes involved in cell wall remodeling, synthesis of osmoprotectants, protection of photosynthetic apparatus, and downregulation of genes involved in cell expansion. The results also highlighted a significant proportion of differentially expressed genes related to phosphate starvation response. In addition, the moderate detrimental effects of drought in the biomass of these tolerant plants were abolished by the addition of phosphate, thus indicating that, besides the ABA-mediated response, acquisition of phosphate could be crucial for the drought tolerance of this common bean genotype. These results provided information about the mechanisms involved in drought response of common bean response that could be useful for enhancing the drought tolerance of this important crop legume

S-Like Ribonuclease T2 Genes Are Induced during Mobilisation of Nutrients in Cotyledons from Common Bean

Germination and seedling development are crucial phases in a plant’s life cycle with economical and agronomical implications. The RNA quality in seeds is linked to seed viability, being an important agronomic trait since this leads to a loss in germination efficiency. In addition, RNA can be an important phosphorous reservoir in seeds, affecting the efficiency of the mobilisation of nutrients towards the seedlings. However, knowledge about the physiological function of ribonucleases during germination and seedling development is scarce. We analysed the ribonuclease activities of cotyledons during these processes and the expression of S-like ribonucleases T2. Ribonuclease activity was detected in cotyledons at 1 day after imbibition and the specific activity increased during germination and seedling development, reaching a maximal value at 10 days after imbibition. At this stage, the levels of proteins and RNA in cotyledons were very low. Using in-gel assays, three ribonucleases were detected with apparent molecular masses of 16, 17 and 19 kDa along cotyledon ontogeny. The S-like ribonucleases T2 family consists of four genes in common bean (PvRNS1 to PvRNS4). The expression of PvRNS1, PvRNS2 and PvRNS4 increased in the phase of nutrient mobilisation in cotyledons. The expression of PvRNS1 increased 1000 fold in cotyledons, from 1 to 6 days after imbibition. The suppression of the induction of ribonuclease activity and gene expression in decapitated seedlings suggests that the regulatory signal comes from the developing axes. These results clearly state that S-like ribonucleases T2 are involved in RNA turnover in cotyledons during seedling development

Local inhibition of nitrogen fixation and nodule metabolism in drought-stressed soybean

Drought stress is a major factor limiting symbiotic nitrogen fixation (NF) in soybean crop production. However, the regulatory mechanisms involved in this inhibition are still controversial. Soybean plants were symbiotically grown in a split-root system (SRS), which allowed for half of the root system to be irrigated at field capacity while the other half remained water deprived. NF declined in the water-deprived root system while nitrogenase activity was maintained at control values in the well-watered half. Concomitantly, amino acids and ureides accumulated in the water-deprived belowground organs regardless of transpiration rates. Ureide accumulation was found to be related to the decline in their degradation activities rather than increased biosynthesis. Finally, proteomic analysis suggests that plant carbon metabolism, protein synthesis, amino acid metabolism, and cell growth are among the processes most altered in soybean nodules under drought stress. Results presented here support the hypothesis of a local regulation of NF taking place in soybean and downplay the role of ureides in the inhibition of NF

Biotecnología de plantas superiores y algas verdes

Los ureidos, alantoína y alantoato, son los principales compuestos sintetizados a partir del nitrógeno fijado en los nódulos de las leguminosas que se exportan a las partes aéreas en leguminosas tropicales como la judía. Los ureidos se producen por la oxidación de las purinas sintetizadas de novo en los nódulos radicales y también como parte de un proceso de recuperación de los compuestos nitrogenados en tejidos senescentes. Los ureidos se acumulan en varios tejidos vegetales en respuesta al estrés hídrico, y se ha sugerido que la acumulación de estos compuestos nitrogenados es la responsable de la inhibición de la fijación de nitrógeno que tiene lugar en condiciones ambientales adversas. A pesar de la importancia crucial de los ureidos como compuestos de reserva y transporte de nitrógeno, hasta el momento no se llevado a cabo la caracterización de las rutas de síntesis y degradación de ureidos en plantas. En particular, parece que existen dos posibles rutas de degradación de alantoato, y que el que determinadas leguminosas usen una u otra ruta puede afectar a la sensibilidad o tolerancia de esas plantas a la sequía. Por tanto la determinación de la ruta que opera en leguminosas de gran interés agronómico como la judía y el garbanzo, puede a la larga tener utilidad biotecnológica con la obtención de plantas que sean capaces de mantener la fijación de nitrógeno en condiciones ambientales adversas, como la sequía. Además de en la caracterización, con fines biotecnológicos del metabolismo de ureidos en leguminosas, se está trabajando obtención de algas superproductoras de γ-tocoferol (vitamina E) mediante ingeniería metabólica, así como en el análisis del contenido en antioxidantes del aceite de oliv

International conference on the healthy effect of virgin olive oil

Ageing represents a great concern in developed countries because the number of people involved and the pathologies related with it, like atherosclerosis, morbus Parkinson, Alzheime's disease, vascular dementia, cognitive decline, diabetes and cancer. Epidemiological studies suggest that a Mediterranean diet (which is rich in virgin olive oil) decreases the risk of cardiovascular disease. The Mediterranean diet, rich in virgin olive oil, improves the major risk factors for cardiovascular disease, such as the lipoprotein profile, blood pressure, glucose metabolism and antithrombotic profile. Endothelial function, inflammation and oxidative stress are also positively modulated. Some of these effects are attributed to minor components of virgin olive oil. Therefore, the definition of the Mediterranean diet should include virgin olive oil. Different observational studies conducted in humans have shown that the intake of monounsaturated fat may be protective against age-related cognitive decline and Alzheimer's disease. Microconstituents from virgin olive oil are bioavailable in humans and have shown antioxidant properties and capacity to improve endothelial function. Furthermore they are also able to modify the haemostasis, showing antithrombotic properties. In countries where the populations fulfilled a typical Mediterranean diet, such as Spain, Greece and Italy, where virgin olive oil is the principal source of fat, cancer incidence rates are lower than in northern European countries. The protective effect of virgin olive oil can be most important in the first decades of life, which suggests that the dietetic benefit of virgin olive oil intake should be initiated before puberty, and maintained through life. The more recent studies consistently support that the Mediterranean diet, based in virgin olive oil, is compatible with a healthier ageing and increased longevity. However, despite the significant advances of the recent years, the final proof about the specific mechanisms and contributing role of the different components of virgin olive oil to its beneficial effects requires further investigations. © 2005 Blackwell Publishing Ltd