TempliPhi: A Sequencing Template Preparation Procedure That Eliminates Overnight Cultures and DNA Purification

Preparing plasmid templates for DNA sequencing is the most time-consuming step in the sequencing process. Current template preparation methods rely on a labor-intensive, multistep procedure that takes up to 24 h and produces templates of varying quality and quantity. The TempliPhi™ DNA Sequencing Template Amplification Kit eliminates the requirement for extended bacterial growth prior to sequencing and saves laboratory personnel hands-on time by eliminating the centrifugation and transfer steps currently required by older preparatory methods. In addition, costly purification filters and columns are not necessary, as amplified product can be added directly to a sequencing reaction. Starting material can be any circular template from a colony, culture, glycerol stock, or plaque. Based on rolling circle amplification and employing bacteriophage Phi29 DNA polymerase, the method can produce 3–5 μg of template directly from a single bacterial colony in as little as 4 h. Implementation of these procedures in a laboratory or core sequencing facility can decrease cost on tips, plates, and other plasticware, while at the same time increase throughput.     

Selenomethionine incorporation in proteins expressed in Lactococcus lactis

Lactococcus lactis is a promising host for (membrane) protein overproduction. Here, we describe a protocol for incorporation of selenomethionine (SeMet) into proteins expressed in L. lactis. Incorporation efficiencies of SeMet in the membrane protein complex OpuA (an ABC transporter) and the soluble protein OppA, both from L. lactis, were monitored by mass spectrometry. Both proteins incorporated SeMet with high efficiencies (>90%), which greatly extends the usefulness of the expression host L. lactis for X‐ray crystallography purposes. The crystal structure of ligand‐free OppA was determined at 2.4 Å resolution by a semiautomatic approach using selenium single‐wavelength anomalous diffraction phasing.     

Controlling activation barrier by carbon nanotubes as nano-chemical reactors

The oxidative addition of primary amine on a monocyclic phospholane was studied in confined conditions. This one-step chemical reaction has been investigated using the DFT technique to elucidate the role of confinement in carbon nanotubes on the reaction. Calculations were carried out by a progressive increase of the nanotube diameters from 10 Å to 15 Å in order to highlight the dependence of the reactivity on the nanotube diameter. First, single point investigations were dedicated to the study of reactants, transition states, and products placed in the different nanotubes while keeping their optimized structure as free compounds. Second, all studied compounds were relaxed inside nanotubes and their geometries were fully optimized. Within these approaches, we proved that the activation barrier could be controlled depending on the confinement, generating a well-controlled catalysis process.     

Design at the atomic level: design of biaryloxazolidinones as potent orally active antibiotics

We have developed a first generation of hybrid sparsomycin-linezolid compounds into a new family of orally bioavailable biaryloxazolidinones that have activity against both linezolid-susceptible and -resistant gram-positive bacteria as well as the fastidious gram-negative bacteria Haemophilus influenzae and Moraxella catarrahalis. The convergent synthesis of these new compounds is detailed.     

A set-up to study photochemically induced dynamic nuclear polarization in photosynthetic reaction centres by solid-state NMR

Recently, solid-state NMR spectroscopy became a viable method to investigate photosynthetic reaction centres (RCs) on the atomic level. To study the electronic structure of the radical cation state of the RC, occurring after the electron emission, solid-state NMR using an illumination set-up can be exploited. This paper describes the illumination set-up we designed for a standard Bruker wide-bore MAS NMR probe. In addition we demonstrate its application to get information from the active site in photosynthetic reaction centres of Rhodobacter sphaeroides R-26 by photochemically induced dynamic nuclear polarization (photo-CIDNP). Solid-state NMR spectra of natural abundance 13C in detergent solubilized quinone depleted photosynthetic reaction centres under continuous illumination showed exceptionally strong nuclear spin polarization in NMR lines. Both enhanced-absorptive and emissive polarization were seen in the carbon spectrum which could be assigned to a bacteriochlorophyll a (BChl a) cofactor, presumably the special pair BChl a. The sign and intensities of the 13C NMR signals provide information about the electron spin density distribution of the transiently formed radical P.+ on the atomic level.     

Preparation of transparent photoluminescence smart window by integration of rare-earth aluminate nanoparticles into recycled polyethylene waste

Novel photoluminescent nanocomposite sheets were prepared for simple commercial manufacturing of transparent and luminous photochromic smart windows. A simple physical integration of lanthanide-doped strontium aluminium oxide (LdSAO) nanoparticles into recycled polyethylene (PE) waste produced a smart nanocomposite with persistent phosphorescence and photochromic properties. Because the nanoparticle form of LdSAO is important for developing transparent materials, LdSAO nanoparticles were well dispersed in the PE matrix. Both the morphologies and chemical compositions of the LdSAO nanoparticles and LdSAO-containing luminescent PE sheets were investigated. Both LdSAO-free and photoluminescent PE sheets were colourless in normal daylight. However the LdSAO-containing PE luminescent samples only exhibited a brilliant green colour under ultraviolet (UV) light and a greenish-yellow colour in the dark as verified by Commission Internationale de l'éclairage laboratory parameters. Both absorbance and emission bands were monitored at 377 and 436/517 nm, respectively. The LdSAO-containing PE luminescent sheets were compared with the LdSAO-free sample using both photoluminescence spectroscopy and for their mechanical properties and were found to have improved scratch resistance, UV protection, and superhydrophobic activity. Due to the added LdSAO, photoluminescence, decay, and lifetime spectral tests confirmed its photochromic fluorescence and long-lasting phosphorescence characteristics. The PE@LdSAO nanocomposite sheets displayed UV protection, photostability, hydrophobicity, and excellent durability compared with the blank LdSAO-free PE sheet.     

Simple preparation of novel photochromic polyvinyl alcohol/carboxymethyl cellulose security barcode incorporated with lanthanide-doped aluminate for anticounterfeiting applications

Forgery and low-quality products pose a danger to society. Therefore, there are increasing demands for the production of easy-to-recognize and difficult-to-copy anticounterfeiting materials. Products with smart photochromic and fluorescence properties can change colour and emission spectra responding to a light source. In this context, we devised a straightforward preparation of a luminescent polyvinyl alcohol/carboxymethyl cellulose (PVA/CMC) nanocomposite to function as a transparent labelling film. The lanthanide-doped aluminate (LdA) was prepared in the nanoparticle form to indicate diameters of 35–115 nm. Different ratios of the LdA were physically dispersed in the PVA/CMC nanocomposite label film to provide photochromic, ultraviolet protection, antimicrobial activity, and hydrophobic properties. Fluorescence peaks were detected at 365 and 519 nm to indicate a colour change to green. As a result of increasing the phosphor ratio, improved superhydrophobic activity was achieved as the contact angle was increased from 126.1° to 146.0° without affecting the film's original physical and mechanical properties. Both ultraviolet (UV) light protection and antibacterial activity were also investigated. The films showed a quick and reversible photochromic response without fatigue. The current strategy reported the development of a photochromic smart label that is transparent, cost effective, and flexible. As a result, numerous anticounterfeiting products can benefit from the current label for a better market. LdA-loaded PVA/CMC films demonstrated antibacterial activity between poor, good, very good, and outstanding as the percentage of LdA in the film matrix increased. The current film can be applied as a transparent photochromic security barcode for anticounterfeiting applications and smart packaging.