Effect of mutations to MBP-p60 on the synthesis of STNV-C RNA.

<p>The upper tier in panel (a) shows 10% SDS-PAGE analysis of the expressed proteins, the lower tier shows 5% denaturing polyacrylamide-8 M urea gel analysis of radio-labelled STNV-C dsRNA. Individual mutations are shown above the respective lanes. Radioactivity was quantified by AIDA and expressed as a percentage of the radio-labelled dsRNA produced by wt MBP-p60 in four parallel assays and the data presented as histograms in panel (b).</p

Analysis of RNA-binding properties of MBP-TNV-D p60 <i>in</i><i>vitro</i>.

<p>Representative electrophoretic mobility shift assay (EMSA) showing interactions between recombinant p60 and ss RNA. The [32P]-labelled satC- RNA probe (28.4 pmol) was incubated with no protein (lane 1) or with MBP-p60 fusion protein at 1, 3, 5, 7, 9, 11 or 13 μg concentration (lanes 2-8, respectively). The unbound (free) RNA probe and the shifted (bound) RNA complexes are marked on the right. The data is expressed in graphical form following phosphorimager analysis and quantification by AIDA. </p

Schematic representation of TNV-D genomic and sub-genomic RNAs and expression and purification of recombinant MBP-TNV-D p60.

<p>In panel (a) open boxes correspond to predicted ORFs including ORFs 1 and 2 which encode proteins p22 and p82 respectively. Protein p60 is predicted from the sequence downstream of the leaky UAG amber stop codon [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0080912#B3" target="_blank">3</a>]. The genomic and sub-genomic TNV-D RNAs encoding the virus proteins and their sizes are shown ABOVE the gene map. Panel B shows expression and purification of recombinant MBP-TNV-D p60 from <i>E. coli</i>. The MBP-p60 fusion protein was expressed at 25°C for 4 h following induction with 0.5 mM IPTG. Proteins were analysed by 10% SDS-PAGE and subjected to Coomassie blue staining. Lane 1 contains protein markers with their molecular masses (in kDa) indicated on the left. Lane 2 contains highly purified MBP-p60 following Superose 6 10/300 column purification.</p

Effect of mutations in the TNV-D p60 domain on RNA replication in <i>Nicotiana benthamiana</i>.

<p>Total RNA extracted from inoculated leaves in panel (a) and systemically infected leaves in panel (b) following inoculation with wt- and mutant RNA transcripts was fractionated by agarose gel electrophoresis and analysed by northern blot hybridisation. TNV-D genomic RNA and two sub-genomic RNAs are indicated by arrows. The tobacco 25S and 18S rRNAs were stained with ethidium bromide for loading purposes. Radioactivity was quantified by AIDA and the results with inoculated and systemically infected leaves are presented as histograms in panels (c) and (d) respectively.</p

Kinetics of RdRP activity of MBP-TNV-D p60 and effects of S1 nuclease treatment on radiolabelled RNA products.

<p>Panel (a) shows representative denaturing gel analysis of radiolabelled RNA products synthesised at 25°C (RT) by <i>in </i><i>vitro</i> transcription using satC- RNA as the template over a 16 h time course. The data is also shown in graphical form quantified by AIDA following phosphorimager analysis. Panel (b) shows the effects of S1 nuclease treatment on radiolabelled RNA products synthesised at 25°C. Products synthesised following 1, 2 or 3 h incubation were untreated (lanes 3, 5 and 7 respectively) or treated with S1 nuclease (lanes 4, 6 and 8 respectively). Radiolabelled products were stained with ethidium bromide in the left hand panel which also shows the template satC- RNA used in these reactions, untreated (lane 1) or treated (lane 2) with S1 nuclease, which is arrowed. Phosphorimaging of the gel is shown in the right hand panel. </p

Conformational Preferences of DNA in Reduced Dielectric Environments

The effect of reduced dielectric environments on the conformational sampling of DNA was examined through molecular dynamics simulations. Different dielectric environments were used to model one aspect of cellular environments. Implicit solvent based on the Generalized Born methodology was used to reflect different dielectric environments in the simulations. The simulation results show a tendency of DNA structures to favor noncanonical A-like conformations rather than canonical A- and B-forms as a result of the reduced dielectric environments. The results suggest that the reduced dielectric response in cellular environments may be sufficient to enhance the sampling of A-like DNA structures compared to dilute solvent conditions

Solution-Phase Synthesis of DNA Amphiphiles for DNA Micellar Assembly

Hydrophobic moieties of amphiphilic DNAs can help DNAs penetrate cell membranes, but the conjugation of hydrophobic moieties to DNAs in solution phase remains challenging. Herein we report a solution-phase synthesis method to conjugate hydrophobic molecules to DNAs. This method is simple and efficient. The resulted amphiphilic DNAs can spontaneously assemble into micelles, which may serve as nanocarriers for cellular delivery of nucleic acids and water-insoluble drugs

Precise Pattern Replication of Polymer Blends into Nonuniform Geometries via Reducing Interfacial Tension between Two Polymers

Patterned polymer structures with different functionalities have many potential applications. Directed assembly of polymer blends using chemically functionalized patterns during spin-coating has been used to fabricate the patterned polymer structures. For bridging the gap between laboratorial experiments and manufacturing of nanodevices, the polymer blends structures are required to be precisely patterned into nonuniform geometries in a high-rate process, which still is a challenge. In this Article, we demonstrated for the first time that by decreasing the interfacial tension between two polymers polystyrene and poly­(acrylic acid) via adding a compatibilizer (polystyrene-<i>b</i>-poly­(acrylic acid) ), a polystyrene/poly­(acrylic acid) blend was precisely patterned into nonuniform geometries in a high-rate fashion. The patterned nonuniform geometries included angled lines with angles varied from 30° to 150°, T-junctions, square arrays, circle arrays, and arbitrary letter-shaped geometries. The reduction in the interfacial tension improved the line edge roughness and the patterning efficiency of the patterned polymer blends. In addition, the commensurability between characteristic length and pattern periodicity for well-ordered morphologies was also expanded with decreasing interfacial tension. This approach can be easily extended to other functional polymers in a blend and facilitate the applications of patterned polymer structures in biosensors, organic thin-film electronics, and polymer solar cells

Experimental and Theoretical Evidence of Enhanced Visible Light Photoelectrochemical and Photocatalytic Properties in MoS₂/TiO₂ Nanohole Arrays

Two-dimensional (2D) ordered micro/nanostructured arrays have attracted intense interest for potential applications in a wide variety of fields, such as surface-enhanced Raman scattering, chemical and biological sensing, catalysis, energy storage, and conversion. In this paper, MoS₂/TiO₂ nanohole arrays are prepared by combing colloidal lithography and dip-coating method. The decorating of MoS₂ nanosheets can significantly improve the photoelectrochemical and photocatalytic activity of TiO₂ nanohole arrays in the visible light region. The photocurrent density of the optimized MoS₂/TiO₂ sample is 17.8 times higher than that of the pristine TiO₂ film, while the enhancement factor of the corresponding kinetic constant in photocatalytic degradation is about 5.2. Our first-principles calculation results are in good agreement with the experimental observations. On the basis of the experimental and theoretical results, such enhanced performances can be assigned to two reasons: one is the improved visible light harvesting owing to MoS₂ nanosheets, and the other is the efficient separation of photogenerated carriers because of band alignment between MoS₂ and TiO₂

High-Efficiency Ferroelectric-Film Solar Cells with an n-type Cu₂O Cathode Buffer Layer

Becasue of the existence of interface Schottky barriers and depolarization electric field, ferroelectric films sandwiched between top and bottom electrodes are strongly expected to be used as a new kind of solar cells. However, the photocurrent with a typical order of μA/cm² is too low to be practical. Here we demonstrate that the insertion of an n-type cuprous oxide (Cu₂O) layer between the Pb­(Zr,Ti)­O₃ (PZT) film and the cathode Pt contact in a ITO/PZT/Pt cell leads to the short-circuit photocurrent increasing 120-fold to 4.80 mA/cm² and power conversion efficiency increasing of 72-fold to 0.57% under AM1.5G (100 mW/cm²) illumination. Ultraviolet photoemission spectroscopy and dark <i>J</i>–<i>V</i> characteristic show an ohmic contact on Pt/Cu₂O, an n⁺–n heterojunction on Cu₂O/PZT and a Schottky barrier on PZT/ITO, which provide a favorable energy level alignment for efficient electron-extraction on the cathode. Our work opens up a promising new method that has the potential for fulfilling cost-effective ferroelectric-film photovoltaic