Problemas de terminología en estudios realizados acerca de "lo que el alumno sabe" sobre ciencias

In this paper we have carried out a bibliographic review of the terms currently used by science education researchers to describe «pupils' knowledge» of Science. Further, we have analised their meanings from the perspective of the methodological framework used and have offered our own proposal, as a result of that review, so as to reach a consensus on both the terminology and the possible range of meanings to bt: used. It must be pointed out that we have excluded those studies which discuss "pupils' knowledge" from a purely psychological perspective because of the enormous amount of bibliography on this topic

Role of LrpC from Bacillus subtilis in DNA transactions during DNA repair and recombination

Bacillus subtilis LrpC is a sequence-independent DNA-binding and DNA-bending protein, which binds both single-stranded (ss) and double-stranded (ds) DNA and facilitates the formation of higher order protein–DNA complexes in vitro. LrpC binds at different sites within the same DNA molecule promoting intramolecular ligation. When bound to separate molecules, it promotes intermolecular ligation, and joint molecule formation between a circular ssDNA and a homologous ssDNA-tailed linear dsDNA. LrpC binding showed a higher affinity for 4-way (Holliday) junctions in their open conformation, when compared with curved dsDNA. Consistent with these biochemical activities, an lrpC null mutant strain rendered cells sensitive to DNA damaging agents such as methyl methanesulfonate and 4-nitroquinoline-1-oxide, and showed a segregation defect. These findings collectively suggest that LrpC may be involved in DNA transactions during DNA repair and recombination

Dispersion of the RmInt1 group II intron in the Sinorhizobium meliloti genome upon acquisition by conjugative transfer

RmInt1 is a self-splicing and mobile group II intron initially identified in the bacterium Sinorhizobium meliloti, which encodes a reverse transcriptase–maturase (Intron Encoded Protein, IEP) lacking the C-terminal DNA binding (D) and DNA endonuclease domains (En). RmInt1 invades cognate intronless homing sites (ISRm2011-2) by a mechanism known as retrohoming. This work describes how the RmInt1 intron spreads in the S.meliloti genome upon acquisition by conjugation. This process was revealed by using the wild-type intron RmInt1 and engineered intron-donor constructs based on ribozyme coding sequence (ΔORF)-derivatives with higher homing efficiency than the wild-type intron. The data demonstrate that RmInt1 propagates into the S.meliloti genome primarily by retrohoming with a strand bias related to replication of the chromosome and symbiotic megaplasmids. Moreover, we show that when expressed in trans from a separate plasmid, the IEP is able to mobilize genomic ΔORF ribozymes that afterward displayed wild-type levels of retrohoming. Our results contribute to get further understanding of how group II introns spread into bacterial genomes in nature

The Selection of Anthropogenic Habitat by Wildlife as an Ecological Consequence of Rural Exodus: Empirical Examples From Spain

[Abstract] The increasing urbanization of the landscape is a major component of global change worldwide. However, it is puzzling that wildlife is selecting anthropogenic habitats despite the availability of apparently high–quality semi–natural (i.e. less intensively modified) habitats. Definitive explanations for this process are still lacking. We have previously suggested that colonization of the urban habitat is initially triggered by ecological processes that take place outside urban areas as a consequence of past rural exodus. Here we present a diverse array of examples of selection of several types of anthropogenic habitat by wildlife in Spain (including transportation infrastructure, human–exclusion areas, urban areas under construction, cities, reservoirs, quarries and landfills) in support of this idea. Wildlife is moving out of its historical ecological refuges and losing fear of harmless urban humans. Mesopredators are rebounding by mesopredator release, due to ceased human persecution, and shrubs and trees are claiming former agricultural habitats. Together, these factors force many species to move to urbanized areas where they find open habitats, food associated with these habitats, and protection against predation. Hence, the classical balance of costs and benefits that takes place once inside urban areas, would actually be a second step of the process of colonization of urban areas. A better understanding of the initial triggers of urban colonization could help us increase the biological value of human–made habitats for wildlife in the future.[Resumen] La fauna silvestre selecciona hábitats antropógenos como consecuencia ecológica del éxodo rural: ejemplos empíricos de España Uno de los principales componentes del cambio global en todo el mundo es el aumento de la urbanización del territorio. Sin embargo, es desconcertante que la fauna silvestre seleccione hábitats antropógenos a pesar de que existan hábitats seminaturales (modificados con menor intensidad) aparentemente de buena calidad. Todavía no existe una explicación definitiva para este proceso. Se ha sugerido con anterioridad que la colonización de los hábitats urbanos se produce en una primera fase a causa de procesos ecológicos que tienen lugar fuera de las zonas urbanas, como consecuencia del éxodo rural del pasado. Para respaldar esta idea, en este estudio presentamos una serie de ejemplos en los que diversas especies de fauna silvestre de España seleccionan varios tipos de hábitats antropogénicos (infraestructuras de transporte, zonas de acceso restringido, zonas urbanas en construcción, ciudades, embalses, canteras y vertederos) por razones asociadas al despoblamiento del rural. La fauna silvestre está saliendo de sus refugios ecológicos y está perdiendo el miedo a los humanos inofensivos de las zonas urbanas. Los mesodepredadores están repuntando debido a la liberación del mesodepredador y al cese de la persecución humana, y la vegetación espontánea está volviendo a colonizar los antiguos hábitats agrícolas. Estos factores obligan a muchas especies a desplazarse a zonas urbanas donde encuentran hábitats abiertos, alimento asociado a estos hábitats y protección contra la depredación. Por consiguiente, el balance de costes y beneficios en el seno de las zonas urbanas, sería en realidad un segundo componente del proceso. Entender mejor los factores iniciales que desencadenan la colonización del medio urbano podría ayudarnos a dar más valor biológico para la fauna silvestre a los hábitats creados por los seres humanos.Xunta de Galicia; ED431C 2018/5

Complete Genome Sequence of the Alfalfa Symbiont Sinorhizobium/ Ensifer meliloti Strain GR4

We present the complete nucleotide sequence of the multipartite genome of Sinorhizobium/Ensifer meliloti GR4, a predominant rhizobial strain in an agricultural field site. The genome (total size, 7.14 Mb) consists of five replicons: one chromosome, two expected symbiotic megaplasmids (pRmeGR4c and pRmeGR4d), and two accessory plasmids (pRmeGR4a and pRmeGR4b).This work was supported by research grants BIO2011-24401 from the Spanish Ministerio de Ciencia e Innovación and CSD 2009-0006 of Programme Consolider-Ingenio, both including ERDF (European Regional Development Funds). L.M.-R. and J.A.L.-C. were supported by predoctoral fellowships (Programs JAE-Predoc and I3P from Consejo Superior de Investigaciones Científicas, respectively). We are particularly grateful to M. G. Claros and R. Bautista from Plataforma Andaluza de Bioinformática (Universidad de Málaga) Spain, to A. J. Fernández-González for bioinformatics support, and to the Estación Experimental del Zaidín—CSIC for DNA sequencing services.Peer reviewe