Effective selection system for experimental evolution of random polypeptides towards DNA-binding protein

An experimental evolution with selection based on binding affinity to DNA was carried out on a library of phage-displayed random polypeptides of about 140 amino acid residues. First, we constructed a system to artificially evolve phage-displayed random polypeptides toward binding to a target DNA containing a restriction enzyme site, in which random polypeptides capable of binding the DNA were recovered as complexes with the target DNA by digestion with the restriction enzyme. The experimental evolution cycle, including the above selection system and random mutagenesis for generating the next mutant library, was repeated until the fourth generation. The ability to bind to the DNA was enhanced per generation. In the fourth generation, convergence of the selected clones to a dominant sequence was observed. These results indicate that the newly constructed selection system is effective for exploring the evolvability of random polypeptides towards DNA-binding proteins.     

Bipolar polymer semiconductor blends of C60‐end‐capped poly(4‐diphenylaminostyrene) and poly(4‐diphenylaminostyrene): One‐pot synthesis and charge‐transport properties

Three types of fullerene (C₆₀)‐end‐capped poly(4‐diphenylaminostyrene) (C₆₀–PDAS) and poly(4‐diphenylaminostyrene) (PDAS) blends were prepared to investigate their potential as bipolar polymer semiconductors. The concentration of C₆₀ in the C₆₀–PDAS/PDAS blends strongly affected the hole and electron drift mobility values; the hole drift mobility decreased with an increase in the C₆₀ concentration. However, the electron drift mobility increased with an increase in the C₆₀ concentration. The hole and electron drift mobility values were almost the same for the 1/2 C₆₀–PDAS/PDAS blend; therefore, this polymer blend was thought to be a bipolar polymer semiconductor. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Normal-state and superconducting properties of Sr2RuO4

We discuss some of the current issues on the copper-free layered perovskite superconductor Sr₂RuO₄, for which a sharp transition at T_c = 1.2 K has been reproducibly obtained. The normal state is characterized as an essentially twodimensional Fermi liquid, and the coherent interlayer transport is established only at low temperatures. The cylindrical Fermi surface observed by de Haas-van Alphen experiments is consistent with other thermodynamic and transport properties. Although the specific heat jump across T_cconfirms the bulk superconductivity, the large residual T-linear term which correlates with the variation in T_cis unusual and suggestive of unconventional pairing.On leave from Hiroshima University.     

Computational study of the transonic flow around a rocket-shaped body

Transonic flows around a rocket were computed using the second-order TVD scheme proposed by Harten for solving the two- and three-dimensional unsteady, compressible Navier-Stokes equations in the conservation-law form. LU-ADI and DD-ADI schemes were employed to the implicit part. The influences of the Reynolds number on the shock-wave/boundary-layer and the shock-wave/vortex interaction were clarified by the two-dimensional analysis. The three-dimensional computations show that there is no stationary shock-wave except near the nose cone. In the wake region, a pair of asymmetrical vortices separates periodically, and the shear layer oscillates. The computed pressure distribution on the surface of the body was compared with that of the three-dimensional experiment. The qualitative agreement of the general profile was good.     

Programmed cell death in the development of the mouse external auditory canal

Programmed cell death (PCD) is an essential event for development. The purpose of this work was to ascertain how PCD, in vivo designated apoptosis, is involved in the development of the external auditory canal. We performed a time sequence study of the distribution of apoptosis during the development of external auditory canal (EAC) of the mouse. ICR mice ranging in age from embryonic day 11.5 (E11.5) to 12 days after birth (DAB) were used in the present study. A part of each head including both ears was removed and was processed according to its purpose. Light and electron microscopy for morphological studies and TUNEL method (Gavrieli et al. [1992] J Cell Biol., 119:493-501) for histochemical studies were used. On E11.5, distinct TUNEL-positive staining occurred in the branchial arch. Between E15.5 and 1DAB, TUNEL-positive cells were observed throughout the EAC and the number of these cells decreased with age. On E15.5 and E16.5, numerous TUNEL-positive cells were observed in a cavity remained in the epithelial plate. Transmission electron microscopy revealed that these cells had the features of apoptosis. From 3-12 DAB, no apoptosis was observed in the EAC except for the terminal differentiation of the skin of the EAC. Apoptosis was not observed during recanalization of the EAC, but occurred during the formation of the epithelial plate. The investigation established that PCD is involved in the formation of the epithelial plate, whereas only cornification of the epithelium of the EAC is associated with recanalization.     

Two methods to prepare nanorings/nanoholes for the fabrication of vertical nanotransistors

A self-assembled monolayer of polystyrene (PS) beads is formed on a silicon wafer by spin-coating. After drying at 80?°C, a thin film of metal/oxide is deposited. During the deposition, the PS beads are detached due to forces such as the inner stress induced by plasma sputtering deposition, mechanical vibration, and centrifugal shearing induced by substrate rotation, resulting in nanoring/nanohole formation. Further experiments demonstrate that the PS?detachment can be controlled by scanning probe microscopy (SPM) tip manipulation. We believe this is a promising set of processes for fabricating nanodevice structures such as those of vertical nanotransistors, which provides high flexibility for nanocrystal characterizations and application for single-electron devices.     

Replication of genetic information with self-encoded replicase in liposomes

In all living systems, the genome is replicated by proteins that are encoded within the genome itself. This universal reaction is essential to allow the system to evolve. Here, we have constructed a simplified system involving encapsulated macromolecules termed a "self-encoding system", in which the genetic information is replicated by self-encoded replicase in liposomes. That is, the universal reaction was reconstituted within a microcompartment bound by a lipid bilayer. The system was assembled by using one template RNA sequence as the information molecule and an in vitro translation system reconstituted from purified translation factors as the machinery for decoding the information. In this system, the catalytic subunit of Qbeta replicase is synthesized from the template RNA that encodes the protein. The replicase then replicates the template RNA that was used for its production. This in-liposome self-encoding system is one of the simplest such systems available; it consists of only 144 gene products, while the information and the function for its replication are encoded on different molecules and are compartmentalized into the microenvironment for evolvability.     

Effect of solar control glazings on human skin temperature

Human skin temperatures were measured under exposure to near-infrared radiation through solar control glazings containing SiWO_x films as solar control materials. It was found that the increase in skin temperature corresponds to the solar transmittance (T_s) value of the glazings. When the hand was exposed to radiation through a glazing containing solar films, the skin temperature after five minutes was less 0.9–1.8°C lower than when the corresponding glass without the films was used. The solar control glazings were effective in reducing the increase in skin temperature.     

A comparative study and phage typing of silage-making Lactobacillus bacteriophages

To investigate basic characteristics of 10 virulent phages active on silage-making lactobacilli, morphological properties, host ranges, protein composition and genome characterization were separated into five groups based on host ranges and basic properties. The seven phages of groups I, II and V were active on Lactobacillus plantarum and Lactobacillus pentosus. Phage phiPY4 (group III) infected both L. casei and Lactobacillus rhamnosus. Phage phiPY5 (group IV) specifically infected Lactobacillus casei. Morphologically, three phages of groups I belonged to the Myoviridae family, while seven other phages of groups II, III and V belonged to the Siphoviridae family. SDS-PAGE profiles, restriction analysis, G + C contents of DNA and Dot blot hybridization revealed a high degree of homology in each group. Clustering derived from host range analysis was closely related to results of DNA and protein analyses. These phages may be applicable to phage typing for silage-making lactobacilli.