Identification and Expression Analysis of Minichromosome Maintenance Proteins in the Silkworm, Bombyx mori

The minichromosome maintenance protein (MCM) family is involved in the regulatory role of DNA replication in eukaryotic organisms. A cDNA encoding of an MCM of the silkworm, Bombyx mori L. (Lepidoptera: Bombycidae), was cloned by reverse transcriptase-polymerase chain reaction (RT-PCR) and sequenced. The resultant amino acid sequence and phylogenetic analysis revealed high identity to MCM, and specifically to MCM7, of vertebrates and invertebrates. An RT-PCR showed that the bmMCM7 transcript was present in the ovaries, testes, silk glands, and fat bodies of larval silkworms. Expression plasmids were transformed into competent Escherichia coli and overexpressed. This is the first report on the identification of MCM helicase of the silkworm, B. mori

The Influence of Mixing Conditions of Reaction Medium on Protease-Catalyzed Peptide Synthesis: The Use of Sonication

Sonication was demonstrated to be a useful method mixing reactoin medium. A model reaction, Boc-Gly-OH + H-Phe-N₂H₂Ph → Boc-Gly-phe-N₂H₂Ph, was adopted to compare two mixing methods of medium, sonication and magnetic-stirring. Under biphasic system including 25% of organic solvent, sonication was preferable to magnetic-stirring for several cosolvents and showed being able to have some potentiality as mixing method. On the other hand another model reaction, Boc-Tyr (Bzl)-OH + H-Gly-N₂H₂Ph→Boc-Tyr (Bzl)-Gly-N₂H₂Ph, which had not been achieved by other investigators, was progressed by the new mixing method. This new method may form other certain reaction-field in the medium.Article信州大学農学部紀要 26(1・2): 21-26(1990)departmental bulletin pape

Terahertz absorption spectra of L-, D-, and DL-alanine and their application to determination of enantiometric composition

Absorption spectra of polycrystalline L-, D-, and DL-alanine have been measured by the terahertz time domain spectroscopy (THz-TDS)in the frequency range from 10 to 90 cm−1 at room temperature. We observed several absorption bands, which have the large difference between enantiomers (L- and D-alanine)and the racemic compound (DL-alanine)in their peak frequencies. This obvious difference shows that the THz absorption bands are strikingly sensitive to the crystal structures. This result indicates that the THz-TDS can be used for distinguishing between the enantiomers and the racemic compound. We propose and demonstrate a method to determine the enantiometric composition of amino acids from the THz absorption spectra

Generation of monocycle efficient terahertz pulses by optical rectification in LiNBO3 at 800 nm

Generation of efficient terahertz (THz) pulses was experimentally made by tilted pump pulse front scheme with a Mg-doped LiNbO3 crystal. In this study, a spitfire laser (Ti:sapphire laser, 800 nm, 3 mJ, 1 kHz) was used as an optical source for the generation and detection of THz pulses. The electro-optic (EO) detection optics consisting of a ZnTe crystal (1 mm in thickness) and a balanced photodetector was used. To obtain optimum THz characteristics and pump to THz power conversion efficiency, the image of the grating was made coincides with the tilted pump pulse front. The maximum THz electric field of 8.5 kV/cm and the frequency bandwidth of 2.5 THz were achieved by using pump pulse energy of 2.4 mJ and pump pulse width of 100 fs. The THz energy of 4.15 μJ was obtained and pump-to-THz conversion efficiency was estimated to be approximately 1.73 x 10-3

Formation of Galactic Center Magnetic Loops

A survey for the molecular clouds in the Galaxy with NANTEN mm telescope has discovered molecular loops in the Galactic center region. The loops show monotonic gradients of the line of sight velocity along the loops and the large velocity dispersions towards their foot points. It is suggested that these loops are explained in terms of the buoyant rise of magnetic loops due to the Parker instability. We have carried out global three-dimensional magneto-hydrodynamic simulations of the gas disk in the Galactic center. The gravitational potential is approximated by the axisymmetric potential proposed by Miyamoto & Nagai (1975). At the initial state, we assume a warm (~ 10^4 K) gas torus threaded by azimuthal magnetic fields. Self-gravity and radiative cooling of the gas are ignored. We found that buoyantly rising magnetic loops are formed above the differentially rotating, magnetically turbulent disk. By analyzing the results of global MHD simulations, we have identified individual loops, about 180 in the upper half of the disk, and studied their statistical properties such as their length, width, height, and velocity distributions along the loops. Typical length and height of a loop are 1kpc and 200pc, respectively. The line of sight velocity changes linearly along a loop and shows large dispersions around the foot-points. Numerical results indicate that loops emerge preferentially from the region where magnetic pressure is large. We argue that these properties are consistent with those of the molecular loops discovered by NANTEN.Comment: 16pages, 10figures. Accepted for publication in PASJ. Replace to higher resolution versio

Dependence of emission of terahertz radiation on geometrical parameters of dipole photoconductive antennas

This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in APPLIED PHYSICS LETTERS. 96(21):211104 (2010) and may be found at https://doi.org/10.1063/1.3436724 .The dependence of the emission spectrum of terahertz (THz) radiation on the geometrical parameters of the dipole antenna, and the relationship between these parameters and the temporal characteristics of the transient current that generate THz radiation, is reported. The emission intensity and the peak frequency strongly depend on these geometrical parameters. This dependence varies significantly with changes in the temporal characteristics of the transient current. We have also found that the emission efficiency can be increased by increasing the aspect ratio for the dipole.ArticleAPPLIED PHYSICS LETTERS. 96(21):211104 (2010)journal articl