The human adenovirus type 5 E1B 55kDa protein interacts with RNA promoting timely DNA replication and viral late mRNA metabolism.

The E1B 55kDa produced by human adenovirus type 5 is a multifunctional protein that participates in the regulation of several steps during the viral replication cycle. Previous studies suggest this protein plays an important role in postranscriptional regulation of viral and cellular gene expression, as it is required for the selective accumulation of maximal levels of viral late mRNA in the cytoplasm of the infected cell; however the molecular mechanisms that are altered or regulated by this protein have not been elucidated. A ribonucleoprotein motif that could implicate the direct interaction of the protein with RNA was initially predicted and tested in vitro, but the interaction with RNA could not be detected in infected cells, suggesting the interaction may be weak or transient. Here it was determined that the E1B 55kDa interacts with RNA in the context of the viral infection in non-transformed human cells, and its contribution to the adenovirus replication cycle was evaluated. Using recombinant adenoviruses with amino acid substitutions or a deletion in the ribonucleoprotein motif the interaction of E1B 55kDa with RNA was found to correlate with timely and efficient viral DNA replication and viral late mRNA accumulation and splicing.

Producción de attisueros para la detección de áido indolacético en cultivos dee bacterias promotoras del crecimiento vegetal / Antisera Production to Detect Indoleacetic Acid in Cultures of Plant-Growth Promoting Bacteria

Se obtuvieron antisueros en conejo utilizando como antígeno el AIA adherido a membranas de nitrocelulosa que mostraron un elevado título y especificidad. Mediante la técnica de inmunoadsorción por manchas marcadas con oro coloidal se detectó la producción de esta auxina por cepas de los géneros Gluconacetobacter, Herbaspirillum, Azospirillum, Pseudomonas, Burkholderia y Bacillus empleando como antígenos los sobrenadantes de los cultivos. Para cuantificar la producción de AIA y corroborar los datos obtenidos se empleó la técnica colorimétrica derivada de Salkowski. Los resultados muestran que todos los géneros bacterianos estudiados tienen la capacidad de producir AIA y se demuestra la factibilidad del uso de este antisuero policlonal para la detección de este metabolito. Teniendo en cuenta las potencialidades de estas bacterias, resulta de gran importancia la utilización de antisueros y técnicas serológicas para la detección rápida y sencilla de este tipo de metabolitos en bacterias asociadas a cultivos de interés económico.

Rabbit polyclonal antisera against indoleacetic acid (IAA) bound to nitrocellulose membrane were obtained, which exhibited a high titer and specificity. The dot immunobinding technique with colloidal gold was used to detect auxin production by several strains belonging to Gluconacetobacter, Herbaspirillum, Azospirillum, Pseudomonas, Burkholderia and Bacillus genera, using culture supernatants as antigens. Moreover, auxin production was quantified by the Salkowski's method to corroborate the previous results. It was found that that all the studied microorganisms produce IAA and the feasibility of using these antisera to detect the metabolite was confirmed. Taking into account the potentialities of plant growth promoting bacteria as biofertilizers, the use of these antisera for a rapid and easy detection of IAA in bacteria associated with important crops is thus recommended.