Showing papers by "Hiroshima University published in 1973"

HELIX-COIL TRANSITION OF POLY-α,L-GLUTAMIC ACID IN AQUEOUS SOLUTION STUDIED BY THE DISSOCIATION FIELD EFFECT RELAXATION METHOD

Abstract: The measurements of dissociation field effect relaxation in aqueous poly-α,L-glutamic acid were carried out. From the feature of pH dependency of relaxation time, the observed relaxation was attributed to the helix-coil transition. The helical growth rate constant was calculated to be (2.9±2)×107 sec−1 from Schwarz’s equation.

Studies of the crystal structure of triglycine sulfate in connection with its ferroelectric phase transition

Abstract: The crystal structure of triglycine sulfate has been refined at 19°C and 37°C in the ferroelectric phase and at 57°C in the paraelectric phase, by using the data collected by a four-circle automatic diffractometer. Positions of 14 hydrogen atoms out of the 17 have been determined and those of the non-hydrogen atoms refined at 19°C, with the discrepancy factor R of 0.046. Refinement of the structures at 37°C and 57°C was made for non-hydrogen atoms, resulting in the R factor of 0.074 in both cases. The split atom method was used for the determination of the 57°C structure. Obtained results have established that the ferroelectric phase transition of TGS is of the order-disorder type.

Enzymatic characteristics of CO-sensitive 26-hydroxylase system for 5beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol in rat-liver mitochondria and its intramitochondrial localization.

Abstract: The enxymatic characteristics of mitochondrial 26-hydroxylase system for 5β-cholestane-3α,7α,12α-triol were studied with rat liver mitochondria and the inner membrane-matrix fractions with special reference to its intramitochondrial localization. 1 Conditions for the assay of enzymatic activity of the hydroxylase system were established with rat liver mitochondrial preparations and inner membrane-matrix fractions derived by digitonin treatment. 2 It was established that rat liver mitochondria, as well as microsomes, possessed the hydroxylase system for 5β-cholestane-3α,7α,12α-triol as an intrinsic constituent. Product analyses revealed that only the mitochondrial hydroxylase system was specifically active for C-26 position. In contrast, the microsomal system was found to be apparently unspecific on C-26 position but rather more active for other adjacent positions. 3 Among the tested citric acid cycle intermediates and nicotinamide coenzymes, isocitrate and NADPH exerted the most remarkable enhancement of the 26-hydroxylase activity. NADP and NADH were totally inert under the present assay conditions. 4 Partial rupture of the mitochondrial structure by hypotonic or digitonin treatment was essential for the reactivity of 26-hydroxylase system under the present experimental conditions. Accessibility to the intramitochondrial reacting site of the exogenous reactants such as NADPH, isocitrate and 5β-cholestane-3α,7α,12α-triol in particular was apparently improved by the partial rupture. 5 The NADPH-dependent or isocitrate-dependent 26-hydroxylase system was totally insensitive to inhibitors of the respiratory electron transfer such as potassium cyanide, antimycin A, rotenone and amytal. However, it was specifically inhibited by phenyl isocyanide. 6 Remarkable sensitivity to carbon monoxide of the 26-hydroxylase system was demonstrated. Apparent Michaelis constant for oxygen and partition coefficient (between carbon monoxide and oxygen) of the 26-hydroxylase system were estimated to be approximately 10–20 μM and 0.1, respectively. Thus, the possible functioning of a “cytochrome P-450”-like entity in intramitochondrial 26-hydroxlase system was proposed. 7 The localization of 26-hydroxylase system was assigned to be in the inner membranematrix region, on the basis of the distribution of intramitochondrial marker enzymes during the course of serial solubilization by digitonin.

An inequality for a functional of probability distributions and its application to Kac's one-dimensional model of a Maxwellian gas

Abstract: where the infimum is taken over all pairs of random variables X and Y defined on (f2, P) and distributed according to f and g respectively; here g is the Gaussian distribution with mean 0 and variance a 2 =~2 (f)e I-f] is sometimes denoted by e IX] when X is a random variable with distribution f. It should be noticed that the value of e [ f ] does not depend upon a choice of the probability space (f2, P). The purpose of this paper is to present some basic properties of e (especially, the inequality (2.2)) together with an application to the central limit theorem and then to show that the functional e is monotone decreasing along Boltzmann solutions of Kac's one-dimensional model of a Maxwellian gas. Some of our results can be generalized to the case of R 3; for example, the functional e similarly defined in R 3 decreases along solutions of Boltzmann's problem for the 3-dimensional Maxwellian gas, but this will be discussed in another occasion.

Projections from the parietal cortex to the brain stem nuclei in the cat, with special reference to the parietal cerebro-cerebellar system.

Abstract: Direct projections from the anterior portions of the parietal cortex of the cat to the brain stem nuclei, especially those sending fibers to the cerebellum, were investigated by the Nauta-Gygax and Fink-Heimer methods. Following unilateral lesions of the anterior portions of the middle suprasylvian and/or lateral gyri, a significant amount of pericellular degeneration was found almost entirely ipsilaterally in the rostral levels of the red nucleus and its vicinities, and in the pontine nuclei. Projection fibers to the pontine nuclei appeared to extend over several longitudinal, columnar zones in the pontine gray. Fibers from the anterior portion of the lateral gyrus were observed mainly in the paramedian and lateral nuclei, and those from the middle suprasylvian gyrus in the ventral, paramedian and lateral nuclei. Degeneration in the nucleus reticularis tegmenti pontis of Bechterew was slight, and found bilaterally with ipsilateral predominance. The significance of the anterior portion of the parietal cortex of the cat as a link of cerebro-cerebellar loops was discussed.

Amino acid replacements in proteins S5 and S12 of two Escherichia coli revertants from streptomycin dependence to independence.

Abstract: Ribosomes were isolated from two E. coli revertants from streptomycin dependence to independence, N660 and d1023. After separation of subunits, proteins were extracted from ribosomal 30S subunits and separated by CM-cellulose column chromatography and gel filtration. Pure S5 and S12 proteins of the two mutants were digested with trypsin and all resulting peptides were isolated by column and paper chromatography. The amino acid compositions of the peptides from the four mutant proteins were compared with the corresponding peptides of the wild type strain A19. The amino acid sequences of non-identical peptides were determined. The following amino acid replacements were found: Glycine by arginine in peptide T2 of protein S5 from mutant N660 and glycine by aspartic acid in peptide T15 of protein S12 from the same mutant. In the other mutant, d1023, arginine in peptide T2 of protein S5 was replaced by leucine and furthermore arginine by serine in peptide T10 of protein S12. Besides the single amino acid replacements mentioned above which are compatible with alterations of single nucleotides, a rather drastic difference between peptides T15 of proteins S12 isolated from strain A19 and mutant d1023 has been detected. The results presented in this paper are compared with amino acid replacements in proteins S5 and S12 from other ribosomal mutants of E. coli.

Rubrobulbar projections in the rabbit. A light and electron microscopic study.

Abstract: The crossed rubrobulbar fibers coursing in association with the classical rubrospinal tract in the rabbit were investigated by means of the Nauta and the Fink-Heimer methods. The synaptic organization within the terminal areas of the rubrobulbar fibers were also studied electron microscopically. The crossed rubrobulbar fibers are distributed to the ventral portion of the reticular area intercalated between the motor and the main sensory nuclei of the trigeminal nerve, to the ventrolateral part of the lateral parvocellular reticular formation, the dorsal region of the facial nucleus, the subtrigeminal portion of the lateral reticular nucleus, and the rostrolateral part of the main portion of the lateral reticular nucleus. Small to medium-sized, electron-dense, degenerated synaptic knobs were observed in the dorsal region of the facial nucleus and in the rostrodorsolateral part of the lateral reticular nucleus. All of the synaptic vesicles contained in the degenerated synaptic bags were spherical. Almost all of the degenerated synaptic terminals were in contact with dendritic profiles. Sporadic electron-dense synaptic knobs contacting the soma of nerve cells were encountered only in the dorsal aspect of the facial nucleus.

Studies on Peptides. XXXVIII. Structure-Activity Correlations in Substance P

Abstract: The undecapeptide amide, H-Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH2, corresponding to the entire amino acid sequence of substance P, a bovine hypothalamic peptide, was synthesized by the conventional method This and C-terminal tetra, penta, hexa, hepta and octapeptide amides were submitted for biological assays Synthetic substance P caused considerable decrease in blood pressure and heart rate in anesthetized rat, but other shorter chain peptides were less active When contractility on isolated guinea-pig ileum was examined, the heptapeptide amide exhibited much higher activity than synthetic substance P

A method to screen anticholesterol substances produced by microbes and a new cholesterol oxidase produced by Streptomyces violascens.

Abstract: A new method to screen anticholesterol substances produced by microbes was devised and the method was applied for cultured broth of Streptomyces. Only one strain, resembled to be Streptomyces violascens, out of more than 200 Streptomyces was determined to produce an anticholesterol substance by this screening method. Furthermore, a new method to measure the anticholesterol activity was established for fermentation and purification of the active component. The partially purified active component was proved to be a new enzyme which oxidized cholesterol to cholest-4-en-3-one. Nicotinamide adenine dinucleotide or nicotinamide adenine dinucleotide phosphate was not necessary for this enzymatic oxidation. It was found that the enzyme was active against the 3β-hydroxyl group on the steroid skeleton but not against the 3α-hydroxyl group by investigating the substrate specificity of the enzyme.

Chloramphenicol resistant mutants of Bacillus subtilis

Abstract: Telve chloramphenicol resistant (CM r)-mutants were isolated from B. subtilis ATCC 6633 and were classified into the following six groups. Group I. No 50s ribosomal protein change was detectable. Ribosomes did not show alteration of the binding ability to CM or to erythromycin in vitro. Group II. A 50s protein, 50a, was altered. Ribosomes did not show alteration of the binding ability to CM or to erythromycin in vitro. The genes specifying the 50a protein was in the cysA-str region on B. subtilis chromosome. Group III. A 50s protein, 50b, was altered. Biological properties of the ribosomes were the same as Group I or II so fas as examined. The genes for 50b protein was in the cysA-str region. Group IV. A 50s protein, 50c, was altered. Ribosomes showed a definite decrease in ability to bind to CM in vitro. The binding of erythromycin to the ribosomes was not impaired. The chromosomal locus of the CM r (and for 50c protein) was in the cysA-str region. Group V. A 50s protein, 50e, was changed. The ability of the ribosomes to bind in vitro both to CM and to erythromycin was greatly reduced. The genetic locus of the CM r (and for 50e protein) was in the cysA-str region. Group VI. A 50s protein, 50f, was altered. Ribosomes showed a decrease in ability to bind in vitro both to CM and to erythromycin. The genes for 50f protein was in the cysA-str region. The results suggest that the ribosomal resistance to CM may be caused by an independent change of at least several 50s ribosomal protein species. The genetic data shown here and those reported previously show that at least two 30s and seven 50s ribosomal protein genes are situated in the cysA-str region on B. subtilis chromosome.

Effects of Glutaraldehyde and Osmium Tetroxide on Hypotrichous Ciliates, and Determination of the Most Satisfactory Fixation Methods for Electron Microscopy

Abstract: SYNOPSIS. In electron microscope studies on hyppotrichous ciliates, cytolysis and/or body deformation–resulting from insufficient contact with glutaraldehyde and poor infiltration of Epon 812, particularly into the buccal cavity, usually were observed. Fixation experiments were carried out to examine the effects of some fixatives on Euplotes eurystomus, Oxytricha bifaria and Stylonychia mytilus to establish the best fixation technic applicable to all species of hypotrichous ciliates. Although the effects of fixation varied considerably with the species, 2 fully satisfactory fixation methods were developed by using OsO4 and glutaraldehyde. In one, a mixture of both fixatives was employed; in the other a very short application of OsO4 was followed by glutaraldehyde. The problem of infiltration was solved by using Spurr's low-viscosity embedding medium in place of Epon 812.

Perturbation Calculation of Gravitational Potentials

Abstract: The static gravitational potential for four-body system in the order of G3 is calculated in the quantized theory. It is derived from the S-matrix elements for scattering of four spinless particles, among which gravitons are exchanged. Feynman's and de Dander's gauges are used for graviton propagator. The potential has contributions from the transverse-traceless part of the graviton field. The potential is different from that obtained in classical theory from the physically acceptable metric tensor derived in our previous paper under new coordi­ nate conditions. Since all other known coordinate conditions such as de Dander's. ones lead to divergent metric tensor at spatial infinity in the post-post-Newtonian approximation, it is not unreasonable that the two potentials become different first in . this order of approximation.

Gamma-Ray Energies and Relative Intensities of 75Se, 108mAg, 113Sn, 131I and 133Ba

Abstract: Gamma-ray energies lower than 500 keV and relative intensities have been precisely measured with Ge(Li) detectors. Many experimental effects such as the source position effect, the counting rate effect, the room temperature effect, etc. are examined. Results are as follows: 303.916±0.012 and 400.624±0.030 keV for 75 Se; 433.932±0.014 keV for 108 m Ag; 255.126±0.010 (3.33±0.13) and 391.686±0.027 keV (100) for 113 Sn; 364.456±0.031 keV for 131 I; 161 (0.98±0.07), 223 (0.76±0.05), 276 (11.6±0.5), 302.839±0.008 (29.6±1.1), 355.999±0.024 (100) and 383.841±0.027 keV (14.9±0.6) for 133 Ba. Parentheses show relative intensities.

Hydrodynamic Calculations of Spherical Gravitational Collapse in the Scalar-Tensor Theory of Gravity

Abstract: Hydrodynamic equations for spherical gravitational collapse in the scalar-tensor theory of gravity are approximated by finite-difference equations. The dynamical motion of a gaseous sphere is calculated numerically on the assumption that the sphere consists of a perfect gas without energy flow and, therefore, its total mass is conserved. In order to avoid the difficulty of ~atching of the metric and scalar fields at .the surface of the gaseous sphere, the sphere is divided into two parts, i.e., a central core and an extended tenuous atmosphere. In the collapsing core, scalar waves are generated around its central region at the final stage, but their effect is not so large as to deviate various physical quantitiEs appreciably from those to be obtained in the general relativistic treatment, except in the inner-most region of self-closure.

The Paramagnetic Curie Temperature of the Alloys Gd(Al1-xCux)2 and Gd(Al1-xNix)2

Abstract: The paramagnetic Curie temperature θ p is measured for the alloys Gd(Al 1- x Cu x ) 2 and Gd(Al 1- x Ni x ) 2 . The values of θ p plotted versus the number of conduction electrons n 0 are found on a single curve. The decrease of θ p with decreasing n 0 is in contradiction with the prediction made by Buschow et al. on the basis of the Ruderman-Kittel-Kasuya-Yosida theory. A reinterpretation of the result based on the same theory is given.