Development of Amphipathic Antimicrobial Peptide Foldamers Based on Magainin 2 Sequence

Magainin 2 ( Mag 2 ), which is isolated from the skin of frogs, is a representative antimicrobial peptide (AMP), exerts its antimicrobial activity via microbial membrane disruption. It has been reported that both the amphipathicity and helical structure of Mag 2 play an important role in its antimicrobial activity. In this study, we revealed that the sequence of 17 amino acid residues in Mag 2 (peptide 7 ) is required to exert sufficient activity. We also designed a set of Mag 2 derivatives, based on enhancement of helicity and/or amphipathicity, by incorporation of α,α-disubstituted amino acid residues into the Mag 2 fragment, and evaluated their preferred secondary structures and their antimicrobial activities against both Gram-positive and Gram-negative bacteria. As a result, peptide 11 formed a stable helical structure in solution, and possessed potent antimicrobial activities against both Gram-positive and Gram-negative bacteria without significant cytotoxicity.     

High-precision imaging of an encapsulated Lindqvist ion and correlation of its structure and symmetry with quantum chemical calculations

Low-voltage aberration-corrected transmission electron microscopy (AC-TEM) of discrete Lindqvist [W(6)O(19)](2-) polyoxometalate ions inserted from an ethanolic solution of [NBu(4)](2)[W(6)O(19)] into double walled carbon nanotubes (DWNTs) allows a higher precision structural study to be performed than previously reported. W atom column separations within the constituent W(6) tungsten cage can now be visualized with sufficient clarity that reliable correlation with structural predictions from density functional theory (DFT) can be achieved. Calculations performed on [W(6)O(19)](2-) anions encapsulated in carbon nanotubes show good agreement with measured separations between pairs of W(2) atom columns imaged within equatorial WO(6) polyhedral pairs and also single W atom positions located within individual axial WO(6) octahedra. Structural data from the tilted chiral encapsulating DWNT were also determined simultaneously with the anion structural measurements, allowing the influence of the conformation of the encapsulating tubule to be included in the DFT calculation and compared against that of other candidate encapsulating nanotubes. Additional DFT calculations performed using Li(+) cations as a model for the [NBu(4)](+) counterions indicate that the latter may help to induce charge transfer between the DWNT and the [W(6)O(19)](2-) ion and this may help to constrain the motion of the ion in situ.     

In Situ Monitoring of Lipid Phase State Make Target Lipid Mixtures Similar to Intercellular Lipid in the Stratum Corneum

In this study, lipid structural change is monitored using Raman spectroscopy during heat treatment, along with the impact of lipid states on the structural and physical properties during the preparation process of the dried and hydrated lipid mixture (LM) similar to intercellular lipid in stratum corneum. The microstructures and thermal behavior of these LMs change depending on the melting of lipid ingredients in the preparation process. It is recognized that variable temperature Raman spectroscopy (VT‐Raman) is a useful and attractive tool for the sensitive in situ monitoring of lipid state changes and lipid melting. The LMs can incorporate D₂O into their structures regardless of preparation temperature due to increasing lattice distance by hydration. These results suggest that monitoring lipid structural changes during the heating step is important to precisely prepare target LMs. Practical Applications: This study reveals that VT‐Raman is a useful and attractive tool in in situ monitoring of lipid state change and lipid melting. The monitoring of the preparation process by VT‐Raman is necessary to precisely prepare the target LM similar to intercellular lipid of stratum corneum because the microstructures and thermal properties of these LMs change depending on the melting of lipid ingredients during the preparation process.     

A Helix‐Stabilized Cell‐Penetrating Peptide as an Intracellular Delivery Tool

Two types of cationic cyclic α,α‐disubstituted α‐amino acids: Api (which possesses a lysine mimic side chain) and Api^C2Gu (which possesses an arginine mimic side chain), were developed. These amino acids were incorporated into an arginine‐based peptide sequence [(l ‐Arg‐l ‐Arg‐dAA)₃: dAA=Api or Api^C2Gu], and the relationship between the secondary structures of the resulting peptides and their ability to pass through cell membranes was investigated. The peptide containing Api^C2Gu formed a stable α‐helical structure and was more effective at penetrating cells than the nonhelical Arg nonapeptide (R₉). Furthermore, the peptide was able to deliver plasmid DNA into various types of cells in a highly efficient manner.     

Improvement of neutron startup source handling work by developing new transportation container for high-temperature engineering test reactor (HTTR)

The high-temperature engineering test reactor (HTTR) has three neutron startup sources (NSs) in the reactor core, each of which consists of ²⁵²Cf with 3.7 GBq, installed in NS holder and subsequently in a control rod guide block (CR block). The NSs are exchanged at the interval of approximately seven years. The NS holders are transported from the dealer's hot cell to the HTTR using a transportation container. The loading work of NS holders to the CR blocks is subsequently carried out in the fuel handling machine maintenance pit of HTTR.

Technical issues, which are the reduction and prevention of radiation exposure of workers and the exclusion of falling of NS holder, were extracted from the experiences in the past two exchange works of NSs to develop a safety handling procedure. Then, a new transportation container special to the NSs of HTTR was developed to solve the technical issues while keeping the cost as low as that for overhaul of conventional container.

As a result, the NS handling work using the new transportation container was safely accomplished by developing the new transportation container which can reduce the risks of radiation exposure dose of workers and exclude the falling of NS holder.     

GTP-binding protein regulates the contractile response elicited by the phorbol ester (PMA)-induced activation of protein kinase C in the isolated rat aorta

1. The aim of the present study was to investigate the involvement of GTP-binding protein in the contractile response induced by activation of protein kinase C (PKC) in isolated rat aorta. The rats were treated with islet-activating protein (IAP) for 4 days prior to the experiments. 2. In the aorta from control rats, phorbol 12-myristate 13-acetate (PMA) produced biphasic contractions; twitch contraction superimposed on the slowly developing contraction. The twitch contraction was abolished by the removal of external Ca2+ or by treatment with nicardipine. In the aorta pretreated with IAP, PMA produced only a slowly developing contraction, and no twitch contraction was induced. 3. The application of Ca2+ to aortic strips in a Ca(2+)-free solution, that had been treated with 10(-6) M PMA caused concentration-dependent contraction, and the contraction was completely inhibited by IAP. 4. Pretreatment with IAP inhibited Ca(2+)-induced contraction of the aorta in Ca(2+)-free medium in the presence of 10(-6) M clonidine, but did not affect the Ca(2+)-induced contraction in the medium treated with 10(-6) M phenylephrine and 10(-7) M nicardipine. 5. These results suggest that the activation of PKC by PMA produces biphasic contractions in the rat aorta. The twitch contraction may be induced by the activation of voltage-dependent Ca(2+)-channels and the activation may be regulated by IAP-sensitive GTP-binding protein.     

Effects of carbamylcholine chloride on human antral gastrin mRNA levels

The effects of the muscarinic receptor agonist, carbamylcholine chloride (carbachol), on gastrin release and gastrin mRNA levels in human antral mucosa (n = 15) were determined. During a-2-h incubation period, carbachol (10(-6)-10(-4) M) decreased gastrin mRNA levels to 71 +/- 8% (10(-6) M), 40 +/- 8% (10(-5) M), and 33 +/- 5% (10(-4) M) of control levels. Carbachol (10(-5) M) decreased intracellular gastrin (from 1634 +/- 103 to 1272 +/- 126 pg/mg tissue protein), while it increased gastrin release into the medium (from 609 +/- 48 to 918 +/- 68 pg/ml per mg tissue protein). After 6- and 9-h culture, carbachol gradually increased gastrin mRNA levels, by 96 +/- 12% and 126 +/- 23%, respectively. Atropine sulfate (10(-5) M) completely inhibited the carbachol-induced changes. Cycloheximide markedly decreased tissue gastrin concentration, but increased gastrin mRNA levels, whereas it had no effects on gastrin release. These findings suggested that carbachol may have a time-related biphasic action on human antral gastrin biosynthesis.     

Consideration of wheel slip and readhesion control for induction traction motor electric locomotives with individual traction control

We have developed a readhesion control algorithm of the traction inverter for individual motor control locomotives. This paper describes improvements in dealing with wheel slip and readhesion control for individual‐axle electric locomotives. The major torque control is based on feedback of the difference between the basic speed of the locomotive and the individual axle speed. By combining two torque control methods, we have obtained better readhesion characteristics: little influence of dynamic axle load transfer and a high achievable coefficient of adhesion exceeding 30%. These torque control characteristics were estimated test runs and the stability limits of feedback gain are shown. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(3): 56–64, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20883     

Plugging problems observed in severe hydrocracking of vacuum residue

Carbons deposited on the filter after the reactor of hydrocracking (US-Sludge) and in the heat exchanger (DS-Sludge) in a commercial H-Oil process were analyzed through the elemental analysis, XRD, SEM, optical microscope, ¹³C-NMR and Raman spectroscopy to elucidate their formation mechanism. Heat treatment of sludge and oil products recovered from the commercial process was performed at 698 K of a reaction temperature. XRD showed the presence of Fe_1−xS, NaCl, and CaSO₄ as well as carbon (2Θ = 26.6°) in US-Sludge. The carbon showed medium and fine mosaic textures surrounding the isotropic grains. DS-Sludge showed mixed texture of domain and flow surrounding the fine mosaic grains. The sludge consisted of stacked carbon flakes with a number of pores on the surface. EDX showed dominant presence of NaCl and CaO particles in the mosaic region. Heat treatment of asphaltene in the product mixed with US-Sludge gave the same appearance to that of DS-Sludge. US- and DS-Sludge are concluded to be formed through the respective carbon formation in the reactor and to be separated on the filter and on the heat exchanger surface, respectively. The carbon particles produced in the reactor collect contaminant Fe_1−xS and CaSO₄ particles to form the agglomerate where the growth and coalescence of the anisotropic spheres are very restricted to form the fine mosaic texture as observed in the US-Sludge. In contrast, the carbonization of the major precipitated heavy aromatic component leads to the domain or flow anisotropic texture through rather free growth and coalescence of anisotropic spheres on the surface of the heat exchanger wall. Although some parts of precipitated component together with US-Sludge give mosaic texture through the restricted growth and coalescence of anisotropic sphere by the presence of reactive fine solids.     

Vortex Pinning/Dynamics in YBCO Films with Jc (77 K) > 3·106 A/cm2 Studied by Direct Transport Measurements

Critical current density, J _c , is studied for highly biaxially-oriented YBCO thin films with J _c (77 K) > 3 MA/cm ² in a range of magnetic fields, temperatures, angles between magnetic field vector and film c-axis. J _c (H, ) is shown to be dominated by vortex interaction with high density (> 10 ¹¹ lines/cm ² ) of linear pins — edge dislocations. A model is developed to describe different vortex arrays behavior in the presence of two-dimensional square network of linear pins.