Importance of Translation–Replication Balance for Efficient Replication by the Self‐Encoded Replicase

In all living systems, the genetic information is replicated by the self‐encoded replicase (Rep); this can be said to be a self‐encoding system. Recently, we constructed a self‐encoding system in liposomes as an artificial cell model, consisting of a reconstituted translation system and an RNA encoding the catalytic subunit of Qβ Rep and the RNA was replicated by the self‐encoded Rep produced by the translation reaction. In this system, both the ribosome (Rib) and Rep bind to the same RNA for translation and replication, respectively. Thus, there could be a dilemma: effective RNA replication requires high levels of Rep translation, but excessive translation in turn inhibits replication. Herein, we actually observed the competition between the Rib and Rep, and evaluated the effect for RNA replication by constructing a kinetic model that quantitatively explained the behavior of the self‐encoding system. Both the experimental and theoretical results consistently indicated that the balance between translation and replication is critical for an efficient self‐encoded system, and we determined the optimum balance.     

Physical properties of 2-hydroxyethyl methacrylate-grafted silk fibers

This paper deals with the physical properties of silk fibers grafted with 2-hydroxyethyl methacrylate (HEMA). Both tensile strength and elongation measured in the dry and wet states gradually decreased with increasing weight gain. The initial modulus of the grafted silk fibers in the dry state sharply increased in the weight gain range of 0–16%, then decreased to a lower value than the reference untreated sample. The refractive indices parallel and perpendicular to the fiber axis decreased, though the former showed a steeper slope. Accordingly, birefringence and isotropic refractive index also decreased, suggesting a lower degree of crystallinity and molecular orientation of grafted silk fibers. DSC, TMA, and TGA curves of the HEMA-grafted silk fibers indicated an increased higher thermal stability of silk fibers due to the HEMA grafting. The dynamic mechanical measurements showed that the thermally induced molecular movement of both amorphous and crystalline domains of silk fibers was enhanced by HEMA grafting. X-ray diffraction curves, however, implied that the crystalline structure of the silk fibroin remained unchanged regardless of HEMA polymerization. The introduction of HEMA polymer in silk fibers was evidenced by the infrared spectra, exhibiting the absorption bands characteristic of either the grafted HEMA polymer and the fibroin molecules with ordered β structure. © 1993 John Wiley & Sons, Inc.     

Measurement of cylindrical form errors using a non-contact detector

Measurement using a spherical tip stylus cannot give a correct assessment of cylindrical form errors of finely turned parts due to their cutting tool marks. The electrostatic-capacitance type gap sensor applied in this research is useful in eliminating the influence of cutting tool marks, which should be regarded as the surface roughness. The sensor does not damage the cylinder surface, as a stylus might. Further, two measuring methods, a round tracing method and a spiral one, were compared     

Low-noise superconducting quantum interference device with a highdV/dΦ optimized by thermally controlling critical current

The transfer function dV/dΦ and the noise characteristics of a low-T_c superconducting quantum interference device (SQUID) have been improved by annealing to adjust the critical current, thereby optimizing the McCumber parameter β_c. A SQUID structure suitable for annealing and using surface nitridation and planarization has also been developed. By annealing a SQUID that initially has a β_c greater than 1, the I-V characteristics can be changed from characteristics with hysteresis to characteristics without hysteresis. A SQUID with β_c=0.81, close to the hysteresis limitation, had a large dV/dΦ (3.7 mV/Φ) and good noise characteristics (1.5 μΦ₀/√(Hz) at 100 Hz and 3.0 μΦ₀/√(Hz) at 1 Hz). These characteristics can be attained even when using a simple measuring circuit connected directly to preamplifier without adaptive components such as flux modulation or additional positive feedback (APF)     

Effect of static magnetic field on thermal conductivity measurement of a molten Si droplet by an EML technique: Comparison between numerical and experimental results

In order to investigate quantitatively the effect of melt convection in an electromagnetically levitated molten droplet on the thermal conductivity of liquid silicon measured by the electromagnetic levitation (EML) technique superimposed with a static magnetic field, the numerical simulations for melt convection in the droplet and additionally, for the measurement of thermal conductivity were carried out. In addition, the thermal conductivity of molten silicon was measured by the EML technique, and then compared with those obtained numerically. In the numerical simulations of melt convection, the buoyancy force, thermocapillary force due to the temperature dependence of the surface tension on the melt surface, and electromagnetic force in the droplet were considered as the driving forces of convection. As a result, the numerical simulations could sufficiently explain the measurement of thermal conductivity by the EML technique under a static magnetic field. Also, it was suggested that a magnetic field of more than 4 T should be applied to measure the real thermal conductivity of molten silicon by the EML technique.     

Viscosity and Thermal Conductivity of 1-Hexyl-3-methylimidazolium Tetrafluoroborate and 1-Octyl-3-methylimidazolium Tetrafluoroborate at Pressures up to 20?MPa

Viscosity and thermal conductivity values are reported for a series of 1-alkyl-3-methylimidazolium tetrafluoroborate compounds with hexyl (1-hexyl-3-methylimidazolium tetrafluoroborate) and octyl (1-octyl-3-methylimidazolium tetrafluoroborate) groups. The viscosity was measured with a rolling-ball viscometer at 293.15 K to 353.15 K and pressures up to 20.0?MPa. The experimental values were correlated with a hybrid VFT–Tait equation. The thermal conductivity was measured using the transient short hot-wire method at 294 K to 335 K and pressures up to 20.0?MPa. The experimental values at 293.15 K and 0.1?MPa agreed with the predicted values proposed by Fr?ba et?al.     

Structural and functional analysis of a novel coiled-coil protein involved in Ypt6 GTPase-regulated protein transport in yeast

The yeast transport GTPase Ypt6p is dispensable for cell growth and secretion, but its lack results in temperature sensitivity and missorting of vacuolar carboxypeptidase Y. We previously identified four yeast genes (SYS1, 2, 3, and 5) that on high expression suppressed these phenotypic alterations. SYS3 encodes a 105-kDa protein with a predicted high alpha-helical content. It is related to a variety of mammalian Golgi-associated proteins and to the yeast Uso1p, an essential protein involved in docking of endoplasmic reticulum-derived vesicles to the cis-Golgi. Like Uso1p, Sys3p is predominatly cytosolic. According to gel chromatographic, two-hybrid, and chemical cross-linking analyses, Sys3p forms dimers and larger protein complexes. Its loss of function results in partial missorting of carboxypeptidase Y. Double disruptions of SYS3 and YPT6 lead to a significant growth inhibition of the mutant cells, to a massive accumulation of 40- to 50-nm vesicles, to an aggravation of vacuolar protein missorting, and to a defect in alpha-pheromone processing apparently attributable to a perturbation of protease Kex2p cycling between the Golgi and a post-Golgi compartment. The results of this study suggest that Sys3p, like Ypt6p, acts in vesicular transport (presumably at a vesicle-docking stage) between an endosomal compartment and the most distal Golgi compartment.     

Phase-separation behavior in a binary mixture fluid layer subjected to a vertical temperature gradient

The phase separation behavior in a layer of an isobutyric acid (IBA)-water binary mixture was observed from the bottom and side of the layer, where the layer was subjected to a vertical temperature gradient spanning the critical temperature. As a result, the following conclusions were obtained. (1) Patterns characterized by a polygonal cell including one droplet, similar to those observed by Assenheimer et al. (Physica A 208 (1994) 373), were formed in a relatively thick liquid layer, e.g., thick, in a limited range of the temperature gradient, although the patterns ultimately disappeared. (2) The growth and extinction rates of the phase-separated droplets increased with ΔT/d, and increased particularly rapidly at high ΔT/d. (3) The formation of the pattern of polygonal cells each with a droplet is considered to be due to thermocapillary motion along the droplet. (4) The concentration-driven buoyancy convection affects the growth rate of the phase-separated droplets. (5) The extinction rate of the phase-separated droplets at the late stage is affected by the thermocapillary motion along the droplet surface.     

Left-sided gallbladder on the basis of a right-sided round ligament

Left-sided gallbladder, a rare congenital anomaly, is defined as a gallbladder located to the left of the round ligament. A 42 year-old female underwent a cholecystectomy for gallstone disease. At laparotomy, we found that the round ligament was located to the right of its normal position and was continuous with the right anterior branch of the portal vein. Though normally situated, the gallbladder was therefore, on the left side of the anomalously right-sided round ligament, fulfilling the definition of a left-sided gallbladder. This case indicates that a third type of left-sided gallbladder may occur in addition to the other forms: one resulting from a right-sided round ligament, in addition to the "true" left-sided gallbladder and the variety seen in situs inversus.