Genotypic comparison of Pantoea agglomerans plant and clinical strains

Pantoea agglomerans strains are among the most promising biocontrol agents for avariety of bacterial and fungal plant diseases, particularly fire blight of apple and pear. However, commercial registration of P. agglomerans biocontrol products is hampered because this species is currently listed as a biosafety level 2 (BL2) organism due to clinical reports as an opportunistichuman pathogen. This study compares plant-origin and clinical strains in a search for discriminating genotypic/phenotypic markers using multi-locus phylogenetic analysis and fluorescent amplified fragment length polymorphisms (fAFLP) fingerprinting.Results: Majority of the clinical isolates from culture collections were found to be improperly designated as P. agglomerans after sequence analysis. The frequent taxonomic rearrangements underwent by the Enterobacter agglomerans/Erwinia herbicola complex may be a major problem in assessing clinical associations within P. agglomerans. In the P. agglomerans sensu stricto (in the stricter sense) group, there was no discrete clustering of clinical/biocontrol strains and no marker was identified that was uniquely associated to clinical strains. A putative biocontrol-specific fAFLP marker was identified only in biocontrol strains. The partial ORF located in this band corresponded to an ABC transporter that was found in all P. agglomerans strains. Conclusion: Taxonomic mischaracterization was identified as a major problem with P.agglomerans, and current techniques removed a majority of clinical strains from this species. Although clear discrimination between P. agglomerans plant and clinical strains was not obtained with phylogenetic analysis, a single marker characteristic of biocontrol strains was identified whichmay be of use in strain biosafety determinations. In addition, the lack of Koch's postulate fulfilment, rare retention of clinical strains for subsequent confirmation, and the polymicrobial nature of P. agglomerans clinical reports should be considered in biosafety assessment of beneficial strains in this species

Periodismo y dispositivos móviles de lecto-escritura. Introducción al diseño de contenidos para tabletas

El lanzamiento de las tabletas, especialmente la iPad de Apple en 2010, abrió la competencia entre las compañías de comunicación en el sentido de hacer disponible el contenido para este entorno de medios emergentes. La fuga de lectores de periódicos impresos y la consecuente caída en las ganancias por publicidad, forzó a las compañías periodísticas a que buscaran los otros medios de mantener sus negocios. La diversificación de productos y la penetración de los periódicos en dispositivos móviles constituyen un escenario prometedor para el medio. El vertiginoso volumen de ventas de las tabletas indica que en 2012 serán comercializadas más de 140 millones de unidades en el mundo. El diseño de los periódicos en tabletas está íntimamente ligado al diseño de la versión impresa por la fuerza de su metáfora. El desafío es encontrar un diseño de páginas propio, aprovechando el potencial multimedia sin interferir negativamente en la legibilidad y en el carácter intrínseco de informar.