918 resultados para conservation of genetic resources
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La normalización de los métodos de análisis y de los principales aspectos relacionados con la conservación de los bienes culturales ha empezado en 2004 con la creación del comité europeo de normalización, CEN/TC 346 Conservation of Cultural Property, que tiene la responsabilidad no solamente de redactar protocolos de ensayos en laboratorio, sino también proponer las recomendaciones más adecuadas para designarlos de forma consensual y conservarlos de la forma más apropiada. Se comentan los aspectos relacionados con el origen de estas normas, el trabajo desarrollado y que muchas de ellas, aunque no estén dirigidas específicamente a la piedra, tienen en cuenta la presencia de este material en objetos arqueológicos, obras de arte, estructuras de fábricas y elementos ornamentales.
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Among the several applications of in vitro tissue culture techniques, the conservation of plant germplasm is one of the most widely used. The cork oak is one of the principal tree species in the Western Mediterranean región. Within this área, the Balearic Islands are considered to be a glacial refuge, and therefore a reservoir of genetic resources. A singular tree has been found in the small Minorca Island population. The haplotype of this tree is of Tyrrhenian origin, showing a past link between Minorca and Sardinia. Moreover, this tree do not bear a deletion within an ITS from ribosimic nuclear DNA, which is fairly common in many populations of this species, and indicates that ir may be the descendant of a very ancient population. This tree is currently in a precarious condition, and it has not produced acorns in the last years. Hence there is a clear need of vegetative propagation to conserve this genotype. We have previously developed methods to clone adult cork oak tres by somatic embryogenesis, and therefore the aim of the present work was to clone this singular tree. There braches from the corwn were collected in November 2004, and methods previously described were carried out. By February 2005 somatic embryogenesis was obtained from leaves of the tree with percentages on induction ranging from 17 to 54% depending on the branch, which may show a novel source of variation that requires further study. Spontaneously matured somatic embryos germinated at 46% in average, and the first somatic seedlings from the Alfavaret's cork oak tree were obtained. Therefore, this study shows one of the most relevant applications of somatic embryogenesis: the plant regeneration of valuable genotypes for the in situ and ex situ conservation of forest genetic resources.
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The main objective of this study was to determine if isozyme systems can be used as markers of genetic deterioration in Brassicaceae seed accessions under different storage conditions. Seed samples of Brassica oleracea, Cardaria draba, Erysimum cheiri, Iberis sempervirens and Rapistrum rugosum were stored for periods of 9 to 30 years at -10°C and 3-4% seed moisture content (long-term or LT conditions) and at 5°C and uncontrolled relative humidity (RH) (short-term or ST conditions). Starch Gel Electrophoresis (SGE) was used to analyse six enzyme systems oriented to determine the genetic deterioration of the accessions studied. The results obtained show that long-term storage conditions (LT) were extremely effective in maintaining the viability of seeds of the five Brassicaceae species studied. The final germination percentages reached by seeds from LT samples ranged from 75 to 100%, while the germination percentages of ST samples (except for B. oleracea) were very low (from 0 to 10%). Similar conclusions were obtained studying the integrity of electrophoretic bands for several isozymes. Two enzyme systems were of special interest: malate dehydrogenase and alcohol dehydrogenase.
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Los títulos de los proyectos de intervención en el patrimonio cultural tangible, como resultado del análisis de una muestra del inventario del fondo documental de la asociación española de empresas de restauración del patrimonio histórico (ARESPA), aporta la evolución de la terminología aplicada en los procesos de conservación. La restauración es una intervención frecuente, aunque en los títulos es común mencionar dos intervenciones. Sin embargo, para facilitar el inventario, catalogación y la consulta de la documentación, y teniendo en cuenta la complejidad del patrimonio construido, se propone especificar en los títulos los ámbitos físicos y los sistemas constructivos relacionados los estudios previos, las obras de emergencia, las intervenciones y el mantenimiento
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Se hace un estudio de los recursos de una sustancia estratégica para la UE, a fin de orientar las investigaciones para un incremento de reservas que garanticen el abastecimiento de esta materia prima de gran demanda
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Lupinus mariae-josephae is a recently discovered endemism that is only found in alkaline-limed soils, a unique habitat for lupines, from a small area in Valencia region (Spain). In these soils, L. mariae-josephae grows in just a few defined patches, and previous conservation efforts directed towards controlled plant reproduction have been unsuccessful. We have previously shown that L. mariae-josephae plants establish a specific root nodule symbiosis with bradyrhizobia present in those soils, and we reasoned that the paucity of these bacteria in soils might contribute to the lack of success in reproducing plants for conservation purposes. Greenhouse experiments using L. mariae-josephae trap-plants showed the absence or near absence of L. mariae-josephae-nodulating bacteria in ‘‘terra rossa’’ soils of Valencia outside of L. mariaejosephae plant patches, and in other ‘‘terra rossa’’ or alkaline red soils of the Iberian Peninsula and Balearic Islands outside of the Valencia L. mariae-josephae endemism region. Among the bradyrhizobia able to establish an efficient symbiosis with L. mariae-josephae plants, two strains, LmjC and LmjM3 were selected as inoculum for seed coating. Two planting experiments were carried out in consecutive years under natural conditions in areas with edapho-climatic characteristics identical to those sustaining natural L. mariae-josephae populations, and successful reproduction of the plant was achieved. Interestingly, the successful reproductive cycle was absolutely dependent on seedling inoculation with effective bradyrhizobia, and optimal performance was observed in plants inoculated with LmjC, a strain that had previously shown the most efficient behavior under controlled conditions. Our results define conditions for L. mariae-josephae conservation and for extension to alkaline-limed soil habitats, where no other known lupine can thrive.
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Conferencia por invitación, impartida el 31 d mayo de 2014 en el Workshop on Language Technology Service Platforms: Synergies, Standards, Sharing at LREC2014
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En las últimas décadas, la agricultura sostenible ha sido objeto de gran interés y debate académico, no sólo en términos conceptuales, sino también en términos metodológicos. La persistencia de la inseguridad alimentaria y el deterioro de los recursos naturales en muchas regiones del mundo, ha provocado el surgimiento de numerosas iniciativas centradas en revitalizar la agricultura campesina así como renovadas discusiones sobre el rol que juega la agricultura como motor de desarrollo y principal actividad para alivio de la pobreza. Por ello, cuando hablamos de evaluar sistemas campesinos de montaña, debemos considerar tanto la dimensión alimentaria como las especificidades propias de los sistemas montañosos como base fundamental de la sostenibilidad. Al evaluar la contribución que han hecho alternativas tecnológicas y de manejo en la mejora de la sostenibilidad y la seguridad alimentaria de los sistemas campesinos de montaña en Mesoamérica, surgen tres preguntas de investigación: • ¿Se está evaluando la sostenibilidad de los sistemas campesinos teniendo en cuenta la variabilidad climática, la participación de los agricultores y las dinámicas temporales? • ¿Podemos rescatar tendencias comunes en estos sistemas y extrapolar los resultados a otras zonas? • ¿Son inequívocamente positivas las alternativas propuestas que se han llevado a cabo? En este trabajo se presentan tres evaluaciones de sostenibilidad que tratan de poner de manifiesto cuáles son los retos y oportunidades que enfrentan actualmente los sistemas campesinos de montaña. En primer lugar, se evalúan tres sistemas de manejo agrícola bajo dos años meteorológicamente contrastantes. Se determinó que durante el año que experimentó lluvias abundantes y temperaturas moderadas, los sistemas de bajos insumos, basados en el uso de abonos orgánicos y rotación de cultivos, obtuvieron los mejores resultados en indicadores ecológicos y similares resultados en los económicos y sociales que el sistema de altos insumos químicos. En el segundo año, con heladas tempranas y sequía invernal, la productividad se redujo para todos los sistemas pero los sistemas más diversificados (en variedades de maíz y/o siembra de otros cultivos) pudieron resistir mejor los contratiempos climáticos. En segundo lugar, se evalúa el grado de conocimiento (percepción) campesino para determinar los factores claves que determinan la sostenibilidad de sus sistemas y su seguridad alimentaria. Se determinó que los principales puntos críticos identificados por los campesinos (tamaño de parcela y pendiente del terreno) afectan de forma significativa a cuestiones de índole económica, pero no son capaces de explicar los desequilibrios alimenticios existentes. Realizando un análisis comparativo entre comunidades que presentaban buenos y malos resultados en cuanto a aporte energético y proteico, se determinó que la seguridad alimentaria estaba relacionada con la sostenibilidad de los sistemas y que concretamente estaba ligada a los atributos de equidad y autonomía. Otro resultado destacable fue que las comunidades más marginales y con mayor dificultad de acceso mostraron mayores niveles de inseguridad alimentaria, pero la variabilidad intergrupal fue muy alta. Eso demuestra que la seguridad alimentaria y nutricional forma parte de un complejo sistema de estrategias de autoabastecimiento ligada a la idiosincrasia misma de cada uno de los hogares. En tercer lugar, se evaluó el desempeño de las escuelas de campo de agricultores (ECAs) en la mejora de la sostenibilidad y la seguridad alimentaria de un sistema campesino de montaña. Para ver el efecto del impacto de estas metodologías a largo plazo, se estudiaron tres comunidades donde se habían implementado ECAs hace 8, 5 y 3 años. Encontramos que el impacto fue progresivo ya que fue la comunidad más antigua la que mejores valores obtuvo. El impacto de las ECAs fue rápido y persistente en los indicadores relacionados con la participación, el acceso a servicios básicos y la conservación de los recursos naturales. El estudio demostró un claro potencial de las ECAs en la mejora general de la sostenibilidad y la seguridad alimentaria de estos sistemas, sin embargo se observó una relación directa entre el aumento de producción agrícola y el uso de insumos externos, lo que puede suponer un punto crítico para los ideales sostenibles. ABSTRACT During the last decades, sustainable agriculture has been the subject of considerable academic interest and debate, not only in conceptual terms, but also in methodological ones. The persistence of high levels of environmental degradation and food insecurity in many regions has led to new initiatives focused on revitalizing peasant agriculture and renewed discussions of the role of sustainable agriculture as an engine for development, environmental conservation and poverty alleviation. Therefore, to assess mountain farming systems, we must consider food dimension and taking into account the specificities of the mountain systems as the foundation of sustainability. When evaluating contribution of technological and management alternative proposals in achieving sustainability and food security for peasant farming systems in Mesoamerican highlands, three research questions arise: • Is sustainability of peasant-farming systems being evaluated taking into account climate variability, participation of farmers and temporal dynamics? • Can we rescue common trends in these systems and extrapolate the results to other areas? • What alternative proposals that have been conducted are unequivocally positives? In this document, we present three evaluations of sustainability that try to highlight the challenges and opportunities that currently face mountain farming systems in Mesoamerica. First, we evaluate the sustainability of three agricultural management systems in two contrasting weather years. We determined that during the first year that exposed heavy rains and moderate temperatures, low-input systems, which are based on the use of organic fertilizers and crop rotation, provided better results in terms of ecological indicators and equal results in terms of economic and social indicators than those achieved using a high chemical input system. In the second year, which featured early frosts and a winter drought, productivity declined in all systems; however, the most diversified systems (in terms of the maize varieties grown and the sowing of other crops) more successfully resisted these climatic adversities. Second, we evaluate the farmers’ perception to determine the key drivers for achieving their sustainability and food and nutritional security. We determined that the key factors identified by farmers (landholding size and slope of cropland) exerted significant impacts on economic disparities but did not explain the malnutrition levels. We compared two contrasting hamlets according to their energy and protein supply, one namely Limón Timoté (LT), which did not present food problems and Limón Peña Blanca (LP), which did exhibit food insecurity. The results showed that FNS is linked to sustainability, and it is primarily related to the sustainability attributes of self-reliance and equity. Although the more marginated and inaccessible community exhibited more food insecurity, food and nutritional security depend upon a complex array of self-sufficiency strategies that remain linked to individual household idiosyncrasies. Third, we evaluated the impact of farmer field schools for improving the sustainability and food security of peasant mountain systems. In order to appreciate the long-term impact, we studied three communities where FFSs were implemented eight, five and three years ago, respectively. We found that FFSs have a gradual impact, as the community that first implemented FFSs scores highest. The impact of FFSs was broad and long-lasting for indicators related to participation, access to basic services and conservation of natural resources. This study demonstrates the potential of FFSs, but more attention will have to be paid to critical indicators in order to scale up their potential in the future. We observed a direct relationship between the increase in agricultural production and the use of external inputs, which is a critical point for sustainable ideals.
Molecular keys to speciation: DNA polymorphism and the control of genetic exchange in enterobacteria
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Speciation involves the establishment of genetic barriers between closely related organisms. The extent of genetic recombination is a key determinant and a measure of genetic isolation. The results reported here reveal that genetic barriers can be established, eliminated, or modified by manipulating two systems which control genetic recombination, SOS and mismatch repair. The extent of genetic isolation between enterobacteria is a simple mathematical function of DNA sequence divergence. The function does not depend on hybrid DNA stability, but rather on the number of blocks of sequences identical in the two mating partners and sufficiently large to allow the initiation of recombination. Further, there is no obvious discontinuity in the function that could be used to define a level of divergence for distinguishing species.
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The pufferfish Fugu rubripes has a genome ≈7.5 times smaller than that of mammals but with a similar number of genes. Although conserved synteny has been demonstrated between pufferfish and mammals across some regions of the genome, there is some controversy as to what extent Fugu will be a useful model for the human genome, e.g., [Gilley, J., Armes, N. & Fried, M. (1997) Nature (London) 385, 305–306]. We report extensive conservation of synteny between a 1.5-Mb region of human chromosome 11 and <100 kb of the Fugu genome in three overlapping cosmids. Our findings support the idea that the majority of DNA in the region of human chromosome 11p13 is intergenic. Comparative analysis of three unrelated genes with quite different roles, WT1, RCN1, and PAX6, has revealed differences in their structural evolution. Whereas the human WT1 gene can generate 16 protein isoforms via a combination of alternative splicing, RNA editing, and alternative start site usage, our data predict that Fugu WT1 is capable of generating only two isoforms. This raises the question of the extent to which the evolution of WT1 isoforms is related to the evolution of the mammalian genitourinary system. In addition, this region of the Fugu genome shows a much greater overall compaction than usual but with significant noncoding homology observed at the PAX6 locus, implying that comparative genomics has identified regulatory elements associated with this gene.
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The achaete-scute genes encode essential transcription factors in normal Drosophila and vertebrate nervous system development. Human achaete-scute homolog-1 (hASH1) is constitutively expressed in a human lung cancer with neuroendocrine (NE) features, small cell lung cancer (SCLC), and is essential for development of the normal pulmonary NE cells that most resemble this neoplasm. Mechanisms regulating achaete-scute homolog expression outside of Drosophila are presently unclear, either in the context of the developing nervous system or in normal or neoplastic cells with NE features. We now provide evidence that the protein hairy-enhancer-of-split-1 (HES-1) acts in a similar manner as its Drosophila homolog, hairy, to transcriptionally repress achaete-scute expression. HES-1 protein is detected at abundant levels in most non-NE human lung cancer cell lines which lack hASH1 but is virtually absent in hASH1-expressing lung cancer cells. Moreover, induction of HES-1 in a SCLC cell line down-regulates endogenous hASH1 gene expression. The repressive effect of HES-1 is directly mediated by binding of the protein to a class C site in the hASH1 promoter. Thus, a key part of the process that determines neural fate in Drosophila is conserved in human lung cancer cells. Furthermore, modulation of this pathway may underlie the constitutive hASH1 expression seen in NE tumors such as SCLC, the most virulent human lung cancer.
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We have asked whether comparative genome analysis and rat transgenesis can be used to identify functional regulatory domains in the gene locus encoding the hypothalamic neuropeptides oxytocin (OT) and vasopressin. Isotocin (IT) and vasotocin (VT) are the teleost homologues of these genes. A contiguous stretch of 46 kb spanning the Fugu IT-VT locus has been sequenced, and nine putative genes were found. Unlike the OT and vasopressin genes, which are closely linked in the mammalian genome in a tail-to-tail orientation, Fugu IT and VT genes are linked head to tail and are separated by five genes. When a cosmid containing the Fugu IT-VT locus was introduced into the rat genome, we found that the Fugu IT gene was specifically expressed in rat hypothalamic oxytocinergic neurons and mimicked the response of the endogenous OT gene to an osmotic stimulus. These data show that cis-acting elements and trans-acting factors mediating the cell-specific and physiological regulation of the OT and IT genes are conserved between mammals and fish. The combination of Fugu genome analysis and transgenesis in a mammal is a powerful tool for identifying and analyzing conserved vertebrate regulatory elements.
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Selected aspects of the evolutionary process and more specifically of the genetic variation are considered, with an emphasis in studies performed by my group. One key aspect of evolution seems to be the concomitant occurrence of dichotomic, contradictory (dialect) processes. Genetic variation is structured, and the dynamics of change at one level is not necessarily paralleled by that in another. The pathogenesis-related protein superfamily can be cited as an example in which permanence (the maintenance of certain key genetic features) coexists with change (modifications that led to different functions in different classes of organisms). Relationships between structure and function are exemplified by studies with hemoglobin Porto Alegre. The genetic structure of tribal populations may differ in important aspects from that of industrialized societies. Evolutionary histories also may differ when considered through the investigation of patrilineal or matrilineal lineages. Global evaluations taking into consideration all of these aspects are needed if we really want to understand the meaning of genetic variation.
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Autoimmune diseases such as systemic lupus erythematosus are complex genetic traits with contributions from major histocompatibility complex (MHC) genes and multiple unknown non-MHC genes. Studies of animal models of lupus have provided important insight into the immunopathogenesis of disease, and genetic analyses of these models overcome certain obstacles encountered when studying human patients. Genome-wide scans of different genetic crosses have been used to map several disease-linked loci in New Zealand hybrid mice. Although some consensus exists among studies mapping the New Zealand Black (NZB) and New Zealand White (NZW) loci that contribute to lupus-like disease, considerable variability is also apparent. A variable in these studies is the genetic background of the non-autoimmune strain, which could influence genetic contributions from the affected strain. A direct examination of this question was undertaken in the present study by mapping NZB nephritis-linked loci in backcrosses involving different non-autoimmune backgrounds. In a backcross with MHC-congenic C57BL/6J mice, H2z appeared to be the strongest genetic determinant of severe lupus nephritis, whereas in a backcross with congenic BALB/cJ mice, H2z showed no influence on disease expression. NZB loci on chromosomes 1, 4, 11, and 14 appeared to segregate with disease in the BALB/cJ cross, but only the influence of the chromosome 1 locus spanned both crosses and showed linkage with disease when all mice were considered. Thus, the results indicate that contributions from disease-susceptibility loci, including MHC, may vary markedly depending on the non-autoimmune strain used in a backcross analysis. These studies provide insight into variables that affect genetic heterogeneity and add an important dimension of complexity for linkage analyses of human autoimmune disease.