Construction and characterization of phage libraries displaying artificial proteins with random sequences

Three phage libraries, PL1, PL2, and PL3, displaying artificial proteins with random sequences were constructed. The artificial proteins, which are model of ancestral proteins, are derivatives of the 25 kinds of random proteins with about 140 amino acid residues produced via random mutagenesis and combinatorial recombination. The random proteins were displayed on the surface of filamentous bacteriophage as fusion protein with the pIII coat protein at an estimated average number on the phage particles in PL1, PL2, and PL3 of 0.32, 0.32, and 0.08, respectively. Each library was shown to express 10(5) to 10(6) kinds of random proteins. With the phage libraries displaying long random peptides, we now have an effective selection system to observe in vitro evolution of new functional proteins from artificial proteins with random sequences.     

Capacity of adsorption of Pb2+ and Ni2+ from aqueous solutions by chitosan produced from silkworm chrysalides in different degrees of deacetylation

The binding capacities of chitin (CT) and chitosan (CS) produced from silkworm chrysalides were investigated aiming at their future application in the removal of Pb2+ and Ni2+ from wastewaters. CS with 75% deacetylation degree (DD) exhibited good binding performance for Pb(2+), but bad efficiency for Ni2+. The maximum binding capacity obtained from isotherms for CS-Pb was 141.10 mg g(-1) and 52.81 mg g(-1) for CS-Ni. The binding capacities for CT were 32.01 mg g(-1) for Pb2+ and 61.24 mg g(-1) for Ni2+. The authors attribute these behaviors to two main factors: (i) the large ionic size of Pb2+ and (ii) the steric hindrance due to CT acetyl groups. Metal binding onto CS was evaluated by the Freundlich and Langmuir isotherm models. The parameter values obtained from the isotherm analysis confirmed that Pb2+ and Ni2+ interact differently with CS and that various factors influence their adsorption. Thermogravimetric analysis (TGA) showed that the thermal behavior of CS with 75% deacetylation degree was in the same profile of standard CS; however, the binding of the metals onto its structure affects the curve profile.     

Screening and investigation of dye decolorization activities of basidiomycetes

The decolorization of industrial dyes was investigated using extracellular enzymes produced by 21 basidiomycetes, mainly edible mushrooms. Among the 27 dyes used in this study, nine were decolorized by over 40%. Most fungi decolorized Acid Orange 20, but they showed different specificities in the case of the other dyes. Determination of activity staining by native polyacrylamide gel electrophoresis revealed that all the decolorization activities corresponded to 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) oxidation activities.     

Effect of lamellar plates on creep resistance in near gamma TiAl alloys

Effect of interlamellar spacings on creep rate in Ti-48 at% Al alloy with fully transformed lamellar structure (FL) has been investigated at 1123 K/98 MPa. In addition, the correlation between creep rate and lamellar orientation to stress axis was elucidated by conducting creep tests at 1148 K/68.6 MPa for three single crystal (SC) specimens of Ti-48 at% Al with different lamellar orientations to stress axis. The difference in creep rate among FL specimens having different interlamellar spacings could not be defined in the early stage of transient creep. The onset of accelerating creep was slightly retarded by decreasing the inter-lamellar spacing. While the creep rate of the SC specimen whose lamellar orientation to stress axis 30–63 ° gradually decreases with increasing strain, and is larger than that of the FL specimen, the creep rate of the SC specimen with lamellar orientation nearly parallel to stress axis drastically decreases within small strain, and is 1/50 smaller than that of the FL specimen. This strong lamellar orientation dependence of creep rate is interpreted by the correlation between dislocation slip system and the lamellar plate.     

Radiosensitization to γ-Ray by Functional Inhibition of APOBEC3G

The radiosensitization of tumor cells is one of the promising approaches for enhancing radiation damage to cancer cells and limiting radiation effects on normal tissue. In this study, we performed a comprehensive screening of radiosensitization targets in human lung cancer cell line A549 using an shRNA library and identified apolipoprotein B mRNA editing enzyme catalytic subunit 3G (APOBEC3G: A3G) as a candidate target. APOBEC3G is an innate restriction factor that inhibits HIV-1 infection as a cytidine deaminase. APOBEC3G knockdown with siRNA showed an increased radiosensitivity in several cancer cell lines, including pancreatic cancer MIAPaCa2 cells and lung cancer A549 cells. Cell cycle analysis revealed that APOBEC3G knockdown increased S-phase arrest in MIAPaCa2 and G2/M arrest in A549 cells after γ-irradiation. DNA double-strand break marker γH2AX level was increased in APOBEC3G-knocked-down MIAPaCa2 cells after γ-irradiation. Using a xenograft model of A549 in mice, enhanced radiosensitivity by a combination of X-ray irradiation and APOBEC3G knockdown was observed. These results suggest that the functional inhibition of APOBEC3G sensitizes cancer cells to radiation by attenuating the activation of the DNA repair pathway, suggesting that APOBEC3G could be useful as a target for the radiosensitization of cancer therapy.     

Reaction mechanism of methane activation using non-equilibrium pulsed discharge at room temperature

The reaction mechanism of methane activation using non-equilibrium pulsed discharge was largely clarified from the emission spectroscopic study and experiments with higher hydrocarbons and some kinds of isotopes. The strong emission of atomic carbon and C₂ swan band system was observed as well as H Balmer series emission. This indicates that methane was highly dissociated into C and H by electron impact, which is consistent with the result of high C₂D₂ composition in produced acetylene when the mixture of CH₄ and D₂ was fed into discharge region. High electron energy contributed to produce atomic carbon directly from methane, and high electron density promoted the dehydrogenation from CH₃, CH₂ and CH to produce atomic carbon consecutively. The reason for the high selectivity to C₂H₂ was the high concentration of CH or C₂ formed from atomic carbon, and the repetition mechanism of decomposition and recombination among C, CH, C₂ and C₂H₂.     

Heuristic optimization in penumbral image for high resolution reconstructed image

Penumbral imaging is a technique which uses the fact that spatial information can be recovered from the shadow or penumbra that an unknown source casts through a simple large circular aperture. The size of the penumbral image on the detector can be mathematically determined as its aperture size, object size, and magnification. Conventional reconstruction methods are very sensitive to noise. On the other hand, the heuristic reconstruction method is very tolerant of noise. However, the aperture size influences the accuracy and resolution of the reconstructed image. In this article, we propose the optimization of the aperture size for the neutron penumbral imaging.