Large-Scale Fabrication of Periodic Nanostructured Materials by Using Hexagonal Non-Close-Packed Colloidal Crystals as Templates

This letter reports a versatile nonlithographic technique for mass fabricating three types of technologically important materialspolymer microwell arrays, 2D-ordered magnetic nanodots, and semiconductor nanopillar arrays, each with high crystalline qualities and wafer-scale sizes. Spin-coated hexagonal non-close-packed silica colloidal crystals embedded in a polymer matrix are used as starting templates to create 2D polymeric microwell arrays. These through-hole arrays can then be used as second-generation templates to make periodic magnetic nanodots and semiconductor nanopillars. This self-assembly approach is compatible with standard semiconductor microfabrication, and complex micropatterns can be created for potential device applications. The wafer-scale technique may find important applications in biomicroanalysis, high-density magnetic recording media, and microphotonics

MOESM1 of Metabolic engineering of Escherichia coli for efficient biosynthesis of fluorescent phycobiliprotein

Additional file 1: Table S1. Primers used in this study. Table S2. Recombinant E. coli strains used in this study. Figure S1. Flowchart of directed evolution of CpcS for improving chromophorylation efficiency of SLA-PEB. Figure S2. Colony PCR for detection of the presence of pCDF-SLA-cpcS and pRSF-PHo1-pebS in E. coli strain SLA-V1. The primers are duetup-2 and T7 terminator. The expression cassette of cpcS in pCDF-SLA-cpcS is 813 bp, and the expression cassette of Ho1 and pebS is 1709 bp. DNA marker: 8000 bp, 5000 bp, 3000 bp, 2000 bp, 1000 bp, 750 bp, 500 bp, 250 bp and 100 bp. Figure S3. Colony PCR for detection of the stability of expression cassette. The primers are duetup-1 and T7 terminator. The size of expression cassette of SLA, CpcS, PHo1 and pebS is 3433 bp. DNA marker: 8000 bp, 5000 bp, 3000 bp, 2000 bp, 1000 bp, 750 bp, 500 bp, 250 bp and 100 bp. Figure S4. HPLC analysis of PEB extracted from E. coli strains. A: SLA-V2; B: SLA-V3; C: SLA-V4B. Figure S5. SDS-PAGE analysis of Ho1s expression in E. coli strains. 1: EBV7, 2: EBVP, 3: EBV6, 4: EBV9, 5: EBVB. The calculated molecular weight is 27.1 kDa for 7Ho1, 26.9 kDa for PHo1, 27.0 kDa for 6Ho1, 26.7 kDa for 9Ho1 and 27.1 kDa for BHo1

Large-Scale Fabrication of Wafer-Size Colloidal Crystals, Macroporous Polymers and Nanocomposites by Spin-Coating

This paper reports a simple spin-coating technique for rapidly fabricating three types of technologically important materialscolloidal crystal, macroporous polymer, and polymeric nanocomposite, each with high crystalline qualities and wafer-scale sizes. Dispersion of monodisperse silica colloids in triacrylate monomers is spin-coated onto a variety of substrates. Shear-induced ordering and subsequent polymerization lead to the formation of three-dimensionally (3D) ordered colloidal crystals trapped inside a polymer matrix. The thickness of as-synthesized colloidal crystal-polymer nanocomposite is highly uniform and can be controlled simply by changing the spin speed and time. Selective removal of the polymer matrix and silica spheres lead to the formation of large-area colloidal crystals and macroporous polymers, respectively. The wafer-scale process is compatible with standard semiconductor microfabrication, as multiple micrometer-sized patterns can be created simultaneously for potential device applications. Normal-incidence transmission spectra in the visible and near-infrared regions show distinct peaks due to Bragg diffraction from 3D ordered structures. The spin-coating process opens a new route to the fundamental studies of shear-induced crystallization, melting and relaxation

A Source of Ultrasensitivity in the Glutamine Response of the Bicyclic Cascade System Controlling Glutamine Synthetase Adenylylation State and Activity in <i>Escherichia coli</i>

Glutamine synthetase (GS) activity in Escherichia coli is regulated by reversible adenylylation, brought about by a bicyclic system comprised of uridylyltransferase/uridylyl-removing enzyme (UTase/UR), its substrate, PII, adenylyltransferase (ATase), and its substrate, GS. The modified and unmodified forms of PII produced by the upstream UTase/UR-PII cycle regulate the downstream ATase-GS cycle. A reconstituted UTase/UR-PII-ATase-GS bicyclic system has been shown to produce a highly ultrasensitive response of GS adenylylation state to the glutamine concentration, but its composite UTase/UR-PII and ATase-GS cycles displayed moderate glutamine sensitivities when examined separately. Glutamine sensitivity of the bicyclic system was significantly reduced when the trimeric PII protein was replaced by a heterotrimeric form of PII that was functionally monomeric, and coupling between the two cycles was different in systems containing wild-type or heterotrimeric PII. Thus, the trimeric nature of PII played a role in the glutamine response of the bicyclic system. We therefore examined regulation of the individual AT (adenylylation) and AR (deadenylylation) activities of ATase by PII preparations with various levels of uridylylation. AR activity was affected in a linear fashion by PII uridylylation, but partially modified wild-type PII activated the AT much less than expected based on the extent of PII modification. Partially modified wild-type PII also bound to ATase less than expected based upon the fraction of modified subunits. Our results suggest that the AT activity is only bound and activated by completely unmodified PII and that this design is largely responsible for ultrasensitivity of the bicyclic system

Wafer-Scale Periodic Nanohole Arrays Templated from Two-Dimensional Nonclose-Packed Colloidal Crystals

This communication reports a simple yet versatile nonlithographic approach for fabricating wafer-scale periodic nanohole arrays from a large variety of functional materials, including metals, semiconductors, and dielectrics. Spin-coated two-dimensional (2D) nonclose-packed colloidal crystals are used as first-generation shadow masks during physical vapor deposition to produce isolated nanohole arrays. These regular nanoholes can then be used as second-generation etching masks to create submicrometer void arrays in the substrates underneath. Complex patterns with micrometer-scale resolution can be made by standard microfabrication techniques for potential device applications. These 2D-ordered nanohole arrays may find important technological applications ranging from subwavelength optics to interferometric biosensors

Reconstitution of <i>Escherichia coli</i> Glutamine Synthetase Adenylyltransferase from N-Terminal and C-Terminal Fragments of the Enzyme

ATase brings about the short-term regulation of glutamine synthetase (GS) by catalyzing the adenylylation and deadenylylation of GS in response to signals of cellular nitrogen status and energy. The adenylyltransferase (AT) activity of ATase is activated by glutamine and by the unmodified form of the PII signal transduction protein and is inhibited by PII-UMP. Conversely, the adenylyl-removing (AR) activity of ATase is activated by PII-UMP and inhibited by unmodified PII and by glutamine. Here, we show that the enzyme can be reconstituted from two purified polypeptides that comprise the N-terminal two-thirds of the protein and the C-terminal one-third of the protein. Properties of the reconstituted enzyme support recent hypotheses for the sites of regulatory interactions and mechanisms for intramolecular signal transduction. Specifically, our results are consistent with the protein activators (PII and PII-UMP) binding to the enzyme domain with the opposing activity, with intramolecular signal transduction by direct interactions between the N-terminal AR catalytic domain and the C-terminal AT catalytic domain. Similarly, glutamine inhibition of the AR activity involved intramolecular signaling between the AT and AR domains. Finally, our results are consistent with the hypothesis that the AR activity of the N-terminal domain required activation by the opposing C-terminal (AT) domain

MOESM1 of Identification of emerging viral genomes in transcriptomic datasets of alfalfa (Medicago sativa L.)

Additional file 1: Primers used in the 5′/3′ RACE and RT-PCR reactions for amplification of the MsAV1-derived products

MOESM3 of Identification of emerging viral genomes in transcriptomic datasets of alfalfa (Medicago sativa L.)

Additional file 3: Nucleotide sequences of the alfalfa strains of cnidium vein yellowing virus (CnVYV-A), lychnis mottle virus (LycMoV-A) and Cactus virus X (CVX-A)

Degenerate primers for homologous region.

<p>Degenerate primers for homologous region.</p

Primers for testing homologous recombination in <i>P</i>. <i>subcordiformis</i> chloroplast.

<p>Primers for testing homologous recombination in <i>P</i>. <i>subcordiformis</i> chloroplast.</p