Clarifying mammalian RISC assembly in vitro

<p>Abstract</p> <p>Background</p> <p>Argonaute, the core component of the RNA induced silencing complex (RISC), binds to mature miRNAs and regulates gene expression at transcriptional or post-transcriptional level. We recently reported that Argonaute 2 (Ago2) also assembles into complexes with miRNA precursors (pre-miRNAs). These Ago2:pre-miRNA complexes are catalytically active <it>in vitro </it>and constitute non-canonical RISCs.</p> <p>Results</p> <p>The use of pre-miRNAs as guides by Ago2 bypasses Dicer activity and complicates <it>in vitro </it>RISC reconstitution. In this work, we characterized Ago2:pre-miRNA complexes and identified RNAs that are targeted by miRNAs but not their corresponding pre-miRNAs. Using these target RNAs we were able to recapitulate <it>in vitro </it>pre-miRNA processing and canonical RISC loading, and define the minimal factors required for these processes.</p> <p>Conclusions</p> <p>Our results indicate that Ago2 and Dicer are sufficient for processing and loading of miRNAs into RISC. Furthermore, our studies suggest that Ago2 binds primarily to the 5'- and alternatively, to the 3'-end of select pre-miRNAs.</p

Gibberellin A1 Metabolism Contributes to the Control of Photoperiod-Mediated Tuberization in Potato

Some potato species require a short-day (SD) photoperiod for tuberization, a process that is negatively affected by gibberellins (GAs). Here we report the isolation of StGA3ox2, a gene encoding a GA 3-oxidase, whose expression is increased in the aerial parts and is repressed in the stolons after transfer of photoperiod-dependent potato plants to SD conditions. Over-expression of StGA3ox2 under control of constitutive or leaf-specific promoters results in taller plants which, in contrast to StGA20ox1 over-expressers previously reported, tuberize earlier under SD conditions than the controls. By contrast, StGA3ox2 tuber-specific over-expression results in non-elongated plants with slightly delayed tuber induction. Together, our experiments support that StGA3ox2 expression and gibberellin metabolism significantly contribute to the tuberization time in strictly photoperiod-dependent potato plants

Girls' disruptive behavior and its relationship to family functioning: A review

Although a number of reviews of gender differences in disruptive behavior and parental socialization exist, we extend this literature by addressing the question of differential development among girls and by placing both disruptive behavior and parenting behavior in a developmental framework. Clarifying the heterogeneity of development in girls is important for developing and optimizing gender-specific prevention and treatment programs. In the current review, we describe the unique aspects of the development of disruptive behavior in girls and explore how the gender-specific development of disruptive behavior can be explained by family linked risk and protective processes. Based on this review, we formulate a gender-specific reciprocal model of the influence of social factors on the development of disruptive behavior in girls in order to steer further research and better inform prevention and treatment programs

Os benefícios dos exercícios resistidos na melhoria da capacidade funcional e saúde dos paraplégicos

Os exercícios resistidos (ER) têm-se mostrado como um dos recursos efetivos para a promoção da saúde e melhoria da capacidade funcional de paraplégicos. Entretanto, o número limitado de estudos sobre a influência dos ER para tal população, acaba por limitar as possibilidades de utilização desta prática. O principal objetivo deste estudo foi realizar uma revisão sobre os benefícios dos ER na melhoria da capacidade funcional e saúde dos paraplégicos. Para tanto, foi realizada uma pesquisa na base de dados do Lilacs, Medline, SportDiscus, SciELO e Scholar Google com o intuito de selecionar as evidências científicas. Os estudos revisados demonstraram que programas de ER são capazes de promover benefícios psicológicos, sociais e físicos, dentre eles a melhoria da aderência ao exercício, melhoria dos níveis de força, resistência e potência, aumento do metabolismo e da melhoria do perfil lipídico aterogênico, e a redução de dores nos ombros em paraplégicos. Os ER são benéficos e até mesmo necessários para manter a capacidade funcional e saúde nesta população

Nanodiamond-rich layer across three continents consistent with major cosmic impact at 12,800 cal BP

A major cosmic-impact event has been proposed at the onset of the Younger Dryas (YD) cooling episode at ≈12,800 ± 150 years before present, forming the YD Boundary (YDB) layer, distributed over 150 million km2 on four continents. In 24 dated stratigraphic sections in 10 countries of the Northern Hemisphere, the YDB layer contains a clearly defined abundance peak in nanodiamonds (NDs), a major cosmic-impact proxy. Observed ND polytypes include cubic diamonds, lonsdaleite-like crystals, and diamond-like carbon nanoparticles, called n-diamond and i-carbon. The ND abundances in bulk YDB sediments ranged up to ≈500 ppb (mean: 200 ppb) and that in carbon spherules up to ≈3700 ppb (mean: ≈750 ppb); 138 of 205 sediment samples (67%) contained no detectable NDs. Isotopic evidence indicates that YDB NDs were produced from terrestrial carbon, as with other impact diamonds, and were not derived from the impactor itself. The YDB layer is also marked by abundance peaks in other impact-related proxies, including cosmic-impact spherules, carbon spherules (some containing NDs), iridium, osmium, platinum, charcoal, aciniform carbon (soot), and high-temperature melt-glass. This contribution reviews the debate about the presence, abundance, and origin of the concentration peak in YDB NDs.We describe an updated protocol for the extraction and concentration of NDs from sediment, carbon spherules, and ice, and we describe the basis for identification and classification of YDB ND polytypes, using nine analytical approaches. The large body of evidence now obtained about YDB NDs is strongly consistent with an origin by cosmic impact at ≈12,800 cal BP and is inconsistent with formation of YDB NDs by natural terrestrial processes, including wildfires, anthropogenesis, and/or influx of cosmic dust