Arenaviruses and lethal mutagenesis. prospects for new ribavirin-based interventions

Lymphocytic choriomeningitis virus (LCMV) has contributed to unveil some of the molecular mechanisms of lethal mutagenesis, or loss of virus infectivity due to increased mutation rates. Here we review these developments, and provide additional evidence that ribavirin displays a dual mutagenic and inhibitory activity on LCMV that can be relevant to treatment designs. Using 5-fluorouracil as mutagenic agent and ribavirin either as inhibitor or mutagen, we document an advantage of a sequential inhibitor-mutagen administration over the corresponding combination treatment to achieve a low LCMV load in cell culture. This advantage is accentuated in the concentration range in which ribavirin acts mainly as an inhibitor, rather than as mutagen. This observation reinforces previous theoretical and experimental studies in supporting a sequential inhibitor-mutagen administration as a possible antiviral design. Given recent progress in the development of new inhibitors of arenavirus replication, our results suggest new options of ribavirin-based anti-arenavirus treatments. © 2012 by the authors; licensee MDPI, Basel, Switzerland.Fundacion Ramón Areces; The Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd); Instituto de Salud Carlos III; Junta de AndalucíaPeer Reviewe

La materia oscura del genoma

The extended view of the genome of organisms as if they were exclusively carriers of genes that contain information to synthesize a protein has been shown to be overly simplistic. The information that numerous media published after the sequencing of the human genome, predicted that as soon as we knew the function of all the “classic” genes we would know the secrets of the genome. This assertion immediately led to the popularization of the term junk DNA.La visión extendida del genoma de los organismos como si fuesen exclusivamente portadores de genes que contienen información para sintetizar una proteína se ha mostrado excesivamente simplista. Las informaciones que publicaron numerosos medios tras la secuenciación del genoma humano, preconizaban que en cuanto supiéramos la función de todos los genes “clásicos” conoceríamos los secretos del genoma. Esta aseveración conllevó inmediatamente la popularización del término DNA basura

Enhanced photostability and sensing performance of graphene quantum dots encapsulated in electrospun polyacrylonitrile nanofibrous filtering membranes

We report a method to encapsulate graphene quantum dots (GQD) in polyacrylonitrile (PAN) nanofibrous membranes to manufacture robust filtering membranes by electrospinning. GQD-PAN membranes with different nanofiber diameter were prepared tuning the electrospinning parameters, all exhibiting the characteristic fluorescence fingerprint of the GQD probes. The photoluminescence (PL) stability of GQD embedded in the PAN fibers was significantly enhanced with respect to that of water dispersed GQD luminescent probes. The PL of GQD-PAN filtering membranes showed remarkable time stability, both stored dry and immersed in phosphate buffer solutions (PBS), as well as exposed to continuous light irradiation. However, the PL intensity of GQD-PAN membranes was irreversibly quenched by highly oxidant free chlorine solutions. Thus, electrospun GQD-PAN membranes exhibited excellent performance as turn-off fluorescence sensing platforms for free chlorine detection in PBS 0.1 M pH 7. The analytical performance of GQD-PAN membranes was comparable to that of GQD solutions with optimal concentrations, displaying a fast (no need of incubation time) and linear response to chlorine concentration in the 10–600 μM range, a low detection limit of 2 μM, high sensitivity, reproducibility and selectivity. Moreover, the sensing performance of the membranes was very stable after being immersed in PBS for months, outperforming the stability of GQD solutions

Template-controlled acidity and catalytic activity of ferrierite crystals

A synthesis strategy to tailor the acid sites location in ferrierite crystals has been developed. The zeolite catalysts were synthesised in fluoride medium using different combinations of organic structure directing agents (SDAs) in the absence of inorganic cations. Therefore, the negative charge associated to the incorporation of aluminium to the framework was compensated exclusively by the positive charge of the organic SDAs. In this way, Al sitting in the zeolite framework was driven by the specific location of the different SDA molecules within the zeolite void volume. Following this synthesis strategy, it has been found that the distribution of strongly acidic hydroxyl groups in the proton form of the zeolites obtained after removal of the organic templates was dependent on the combination of organic molecules used as SDAs. Moreover, the catalytic activity of the zeolites in m-xylene and 1-butene isomerisation increased as the relative population of strong Brönsted acid groups in sterically constrained sites inside the ferrierite cavity decreased.This work has been financially supported by the MICINN (project CTQ2006-06282).Peer reviewe

Lineamientos para la gestión de documentos electrónicos de la Unidad de Gestión documental y Archivo del Centro Nacional de Registro

El siguiente informe presenta un proyecto de investigación que se realizó en la Unidad de Gestión documental y Archivo del Centro Nacional de Registros, en donde a través de entrevistas a la jefa de la Unidad y visitas a la institución, se conoció en qué condiciones se encuentran los documentos electrónicos que se generan a diario en las distintas dependencias con las que cuenta. La principal problemática de la institución radica en que no cuentan con una normativa o lineamientos que guíen al personal en los procesos con los documentos electrónicos, es por ello que con la finalidad de apoyar a la UGDA de la institución, se vio a bien la creación de una propuesta en la que se describen cuatro lineamientos enfocados al tratamiento archivístico de este tipo de documentos, a fin de contribuir en la evolución e implementación de la Gestión documental electrónica que esta institución está desarrollando. Asimismo, la creación de estos lineamientos se realizó con el propósito de generar una mayor facilidad para realizar ciertos procesos archivísticos, como: clasificación, ordenación, eliminación, control de inventarios, las transferencias documentales y sobre todo la conservación del mismo. Todo esto con el fin de sumar en las competencias tecnológicas y archivísticas de los involucrados

Influence of Al distribution and defects concentration of ferrierite catalysts synthesized from Na-free gels in the skeletal isomerization of n-butene

The skeletal isomerization of n-butenes to isobutene has been carried out over ferrierite catalysts (Si/Al ~ 15) containing different acid sites distribution and different amount of defects. The zeolite crystals were synthesized under hydrothermal conditions in fluoride medium in the absence of alkaline cations by using suitable combinations of structure directing agents. Template-driven low density of acid sites in 10-membered-ring channels enhances the isobutene selectivity and decreases catalyst deactivation. The presence of high amount of silanol groups and Lewis acid sites increases the yields of by-products and catalysts decay.MICINN (CTQ2006-06282) CSIC (JAE-doc contract)Peer reviewe

Natural Hosts and Genetic Diversity of the Emerging Tomato Leaf Curl New Delhi Virus in Spain

Knowledge about the host range and genetic structure of emerging plant viruses provides insights into fundamental ecological and evolutionary processes, and from an applied perspective, facilitates the design and implementation of sustainable disease control measures. Tomato leaf curl New Delhi virus (ToLCNDV) is an emerging whitefly transmitted begomovirus that is rapidly spreading and inciting economically important diseases in cucurbit crops of the Mediterranean basin. Genetic characterization of the ToLCNDV Mediterranean populations has shown that they are monophyletic in cucurbit plants. However, the extent to which other alternative (cultivated and wild) hosts may affect ToLCNDV genetic population structure and virus prevalence remains unknown. In this study a total of 683 samples from 13 cultivated species, and 203 samples from 24 wild species from three major cucurbit-producing areas of Spain (Murcia, Alicante and Castilla-La Mancha) from five cropping seasons (2012–2016) were analyzed for ToLCNDV infection. Except for watermelon, ToLCNDV was detected in all cultivated cucurbit species as well as in tomato. Among weeds, Ecballium elaterium, Datura stramonium, Sonchus oleraceus, and Solanum nigrum were identified as alternative ToLCNDV plant hosts, which could act as new potential sources of virus inoculum. Furthermore, we performed full-genome deep-sequencing of 80 ToLCNDV isolates from different hosts, location and cropping year. Our phylogenetic analysis supports a Mediterranean virus population that is genetically very homogeneous, with no clustering pattern, and clearly different from Asian virus populations. Additionally, D. stramonium displayed higher levels of within-host genetic diversity than cultivated plants, and this variability appeared to increase with time. These results suggest that the potential ToLCNDV adaptive evolution occurring in wild plant hosts could serve as a source of virus genetic variability, thereby affecting the genetic structure and spatial-temporal dynamics of the viral population

Pathogenic strains of Shewanella putrefaciens contain plasmids that are absent in the probiotic strain Pdp11

Shewanella putrefaciens Pdp11 is a strain described as a probiotic for use in aquaculture. However, S. putrefaciens includes strains reported to be pathogenic or saprophytic to fish. Although the probiotic trait has been related to the presence of a group of genes in its genome, the existence of plasmids that could determine the probiotic or pathogenic character of this bacterium is unknown. In the present work, we searched for plasmids in several strains of S. putrefaciens that differ in their pathogenic and probiotic character. Under the different conditions tested, plasmids were only found in two of the five pathogenic strains, but not in the probiotic strain nor in the two saprophytic strains tested. Using a workflow integrating Sanger and Illumina reads, the complete consensus sequences of the plasmids were obtained. Plasmids differed in one ORF and encoded a putative replication initiator protein of the repB family, as well as proteins related to plasmid stability and a toxin-antitoxin system. Phylogenetic analysis showed some similarity to functional repB proteins of other Shewanella species. The implication of these plasmids in the probiotic or pathogenic nature of S. putrefaciens is discussed