Showing papers by "Osaka University published in 1977"
TL;DR: The mutation diminishes UV mutagenesis and UV reactivation of phages λ without affecting the inducibility of phophage λ nor the inhibition of cell division following UV irradiation.
Abstract: Mutants of E. coli defective in susceptibility to UV-induction of mutations were isolated by direct screening for their UV nonmutable phenotype (Umu-). Screening of about 30,000 mutagenized clones of a uvr-B derivative of AB1157 yielded six Umu- strains. The mutants can be classified into three groups by the location of the mutations, umuA, umuB and umuC. Mutations umuA and umuB are, respectively, mapped close to lexA and recA genes and mutations at both loci partially reduce UV mutagenesis. The locus of umuC is between hemA and purB and the mutations at this new locus result in a moderate increase of UV sensitivity. The mutation diminishes UV mutagenesis and UV reactivation of phage lambda without affecting the inducibility of phophage lambda nor the inhibition of cell division following UV irradiation. Related properties of an isogenic strain of a recF- mutant are compared with those of umuC-.
546 citations
TL;DR: The light-induced changes in pH and ATP level were compared for cell suspensions between strains of Halobacterium halobium differing in pigmentation after growth under the same conditions and the presence of a bacteriorhodopsin different from that in the purple membrane is postulated.
316 citations
TL;DR: It is found that tissue mast cells can be derived from grafted bone marrow cells in irradiated mice, using the giant granules of beige mouse5 as a quantitative marker for mast cells.
Abstract: BOTH basophilic granulocytes and tissue mast cells are known to have receptors for immunoglobulin E (IgE) and granules which contain histamine and heparin1,2. In spite of their similar physiological role, these two types of cells are thought to be independent cell lineages; the former are derived from the bone marrow, and the latter are connective tissue cells2. The differentiation of mast cells from their precursors, which were supposed to be undifferentiated mesenchymal cells, and the proliferation of these precursors were reported to occur in the skin of mice3,4. These results do not necessarily exclude the possibility that the precursor cells themselves are originated from the bone marrow, however. To examine such a possibility, we investigated whether mast cells of the donor origin appeared in radiation chimaeras, using the giant granules of beige (Chediak–Higashi syndrome) mouse5 as a quantitative marker for mast cells. We have found that tissue mast cells can be derived from grafted bone marrow cells in irradiated mice.
303 citations
TL;DR: It is suggested that there may be at least two pools of glutathione, a labile fraction which probably serves as a reservoir of cysteine which can be released by gamma-glutamyl-transferase when necessary.
Abstract: Rat liver contains a high concentration (7-8mM) of reduced glutathione and its level changes rapidly when starving or feeding rats. We concluded that one of the functions of liver glutathione was to act as a reservoir of cysteine. When starved rats were fed a protein-free diet, the increase in liver glutathione was dependent on the amount of cysteine added to the diet. A cysteine-dependent increase of glutathione was also observed in rats fed a diet containing gelatin with cysteine, but the increase was relatively lowered compared with rats fed a protein-free diet containing the same amount of cysteine. This suppression of the increase in glutathione was observed much more clearly when the gelatin diet was fortified with tryptophan in addition to cysteine. In the presence of tryptophan, L-[35S]-cysteine in the diet appeared to be incorporated primarily into liver and serum proteins, and degradation of liver glutathione must also have been enhanced. Addition of excess cysteine to the diet masked the effects of gelatin and tryptophan, stimulated glutathione synthesis in the liver as well as incorporation of dietary cysteine into protein fractions. Prolonged starvation of rats or injection of dibutyryl-3',5'-cyclic AMP lowered the glutathione level,but the level did not decrease below 2 to 3 mM. These findings suggest that there may be at least two pools of glutathione. A labile fraction, constituting one-third to one-half the total liver glutathione, probably serves as a reservoir of cysteine which can be released by gamma-glutamyl-transferase when necessary.
208 citations
TL;DR: These derivatives were the most effective inhibitors of trypsin, plasmin, plasma kallikrien and thrombin, and they strongly inhibited the esterolytic activities of C1r- and C1 esterase.
184 citations
TL;DR: In this paper, a thermal decomposition of manganese nitrate solution on a titanium or a platinum substrate was investigated mainly in 1N H2SO4 and 1N KOH.
184 citations
TL;DR: Steady state plasma glucose level (SSPG) which should be inversely proportional to insulin sensitivity was obtained and mean value of insulin sensitivity indices was significantly reduced compared with normal in 6 adult-onset non-obese untreated diabetics.
Abstract: Glucose, insulin and somatostatin infusion over 2 hours effectively suppressed endogenous secretion of insulin, glucagon and growth hormones. Steady state plasma glucose level (SSPG) which should be inversely proportional to insulin sensitivity was obtained. In 6 adult-onset non-obese untreated diabetics, mean value of insulin sensitivity indices was significantly reduced compared with normal. In 5 insulin-treated diabetics and in 5 subjects with borderline glucose tolerance including 2 obese subjects, insulin sensitivity for glucose utilization was also significantly diminished.
178 citations
TL;DR: In this article, it was shown that ethanol can give a metastable crystalline phase (crystal-II) when the liquid was cooled at a moderate rate and the residual entropy was found to be 97 K, 35.3 JK −1 mol −1, and 8.93 J K −1mol −1 for the glassy liquid.
177 citations
TL;DR: The present radioimmunoassay eliminates both extraction of aldosterone from serum and chromatographic separation and requires only 0.1 ml of serum for assay.
Abstract: A direct radioimmunoassay for serum aldosterone was developed using a highly specific sntibody and 8-anilino-1-naphthalene sulfonic acid as a blocking agent to inhibit the binding of aldosterone to serum proteins. 125I-labeled aldosterone was used as the labeled antigen and polyethylene glycol was used to separate antibody-bound and free aldosterone. The minimum detectable concentration was 1.5 pg/tube. There were excellent correlations between the present method and other methods, i.e., 1) a method using tritiated aldosterone, 2) a method using dichloromethane extraction before assay, and 3) a commercial kit method. The intra-assay coefficient of variation was 6.9%, and the inter-assay coefficient of variation was 10.7%. The values found in normal human serum were comparable with those reported using other methods. The present radioimmunoassay eliminates both extraction of aldosterone from serum and chromatographic separation and requires only 0.1 ml of serum for assay.
176 citations
TL;DR: In this paper, the normal vibrations of β-d -glucopyranose have been investigated using the Urey-Bradley force field, and vibrational assignments of the observed bands are made on the basis of the potential energy distributions.
156 citations
TL;DR: The possibility that the same NA neurons might innervate both the fore brain and spinal cord has been presented, as the source of NA in the forebrain, such as the hypothalamus and preoptic area, was considered.
Abstract: The origin of the spinal cord noradrenaline (NA) has been investigated by means of the horseradish peroxidase (HRP) method, combined with monoamine oxidase staining (Glenner) to identify the NA neurons. Following the injection of HRP to the various levels of rat spinal cord, cervical to sacral cord, A1–3, 5–7 NA neuron groups were labeled with HRP. They showed almost the same distribution pattern regardless of difference in the injected segment. Labeled NA neurons in A6 were concentrated in the ventral division of the locus coeruleus, which continued to the labeled NA neurons in the subcoeruleus area. The HRP positive neurons in the pons outnumbered those of the medulla oblongata. As the NA neurons described above were considered to be the source of NA in the forebrain, such as the hypothalamus and preoptic area, the possibility that the same NA neurons might innervate both the forebrain and spinal cord has been presented.
TL;DR: A new method is presented for the isolation of catecholamines in biological fluids using boric acid gel that offers some advantages over the previous aluminum oxide method with respect to simplicity, reproducibility, and recovery.
TL;DR: In this article, the effects of the size and shape of the magnesium phase, the solubility of the alloying elements in magnesium and the grain size on the behaviour of internal friction and Young's modulus were examined and discussed.
Abstract: The effects of additions of nickel to magnesium over the composition range from 0 to 40.41 and of copper, aluminium, and tin to magnesium by 15.10%, 18.40%, and 21.40%, respectively, on the internal friction and Young's modulus have been investigated by use of the flexural vibration method at room temperature. It was generally found that the Mg-Mg2Ni hypo-eutectic alloy samples had the well-defined amplitude-dependence of internal friction which resulted in a very high damping capacity at higher stress levels. The damping capacity of the eutectic and hyper-eutectic samples of the Mg-Mg2Ni alloy and also of the hypo-eutectic samples of the Mg-Mg2Cu, Mg-Mg17Al12, and Mg-Mg2Sn alloys was not so high as that of the hypo-eutectic samples of the Mg-Mg2Ni alloy. The effects of the size and shape of the magnesium phase, the solubility of the alloying elements in magnesium and the grain size on the behaviour of internal friction and Young's modulus were examined and discussed. The results were explained in terms of the vibrating string model of the dislocations in magnesium which were pinned weakly by impurity atoms. It is concluded that the very small solubility of nickel in magnesium and the dendritic or globular shape of the primary magnesium in the Mg-Mg2Ni hypo-eutectic samples are responsible for the much lower breakaway stress than that in other alloys and pure magnesium samples. (Received October 21, 1976)
TL;DR: A study of the α-subunit of tryptophan synthetase of Escherichia coli suggests that the stability of a protein may be highly correlated with the hydrophobicity of the amino acid residues at some suitable positions.
Abstract: THE role of individual amino acid residues in stabilising protein molecules is of interest, especially in connection with the mechanism of thermoresistance of thermophilic bacteria1 and in connection with the physicochemical basis of temperature sensitive mutants used widely in molecular biology studies. This problem has been approached mainly with the use of synthetic polypeptide2, chemical modification of natural proteins3, or homologous proteins4–9 from different species. Many mutants of microorganisms are available from genetic studies, however, in which the mutant proteins differ from wild type only at a single amino acid position. Such proteins often differ markedly in stability. We describe here a study of the α-subunit of tryptophan synthetase of Escherichia coli. The data suggest that the stability of a protein may be highly correlated with the hydrophobicity of the amino acid residues at some suitable positions. Further studies of this type may clarify the role of individual amino acid residues in stabilising proteins.
TL;DR: In this paper, a new result in the problem of pole assignment by gain output feedback is given, which states that arbitrary pole assignment is possible for almost all systems if n, r and m are the number of states, of inputs and of outputs, respectively, and ν and μ are the controllability index and the observability index of the system, respectively.
Abstract: In this paper a new result in the problem of pole assignment by gain output feedback is given. Roughly speaking, this result says that arbitrary pole assignment is possible for almost all systems if n \mu, m \geq
u . Here n, r and m are the number of states, of inputs and of outputs, respectively, and ν and μ are the so-called controllability index and the observability index of the system, respectively. This result extends the author's previous one in [1]. The basic idea in [1] is developed further and its geometrical meaning is amplified. The proof of the theorem itself gives a method of constructing a desired gain matrix. An example is given to show the feasibility of the algorithm.
TL;DR: The ineffectiveness of an ATP analog, AMP-PNP, and the synergism of ATP and Mg2+ in maintaining the membrane potential and excitability strongly suggest that ATP act via its hydrolysis by M g2+-activated ATPase.
Abstract: Electric characteristics of internodalChara australis cells, from which the tonoplast had been removed by vacuolar perfusion with media containing EGTA, were studied in relation to intracellular concentrations of ATP and Mg2+ using the ordinary microelectrode method and the open-vacuole method developed by Tazawa, Kikuyama and Nakagawa (1975.Plant Cell Physiol.16:611). The concentration of ATP was decreased by introducing hexokinase and glucose into the cell and that of Mg2+ by introducing EDTA or CyDTA. The membrane potential decrease and the membrane resistance increase were both significant when the ATP or Mg2+ concentration was decreased. An ATP-dependent membrane potential was also found in other species of Characeae,Nitella axillaris andN. pulchella. Excitability of the membrane was also completely lost by reducing the ATP or Mg2+ concentration. Both membrane potential and excitability were recovered by introducing ATP or Mg2+ into ATP- or Mg2+-depleted cells.
TL;DR: A traveling-wave electrooptic phase modulator using a Ti-in-diffused LiNbO 3 optical waveguide was designed and constructed with emphasis placed on broad-band operation.
Abstract: A traveling-wave electrooptic phase modulator using a Ti-in-diffused LiNbO 3 optical waveguide was designed and constructed with emphasis placed on broad-band operation. As a microwave waveguide, a coplanar parallel stripline of aluminum with characteristic impedance of 48 Ω was fabricated on the crystal surface. The electrodes are 1.5 μm thick, 1 cm long, and 60 μm apart. The modulator was tested at 0.63 μm over a bandwidth of 7.5 GHz. For 250-mW drive power, the measured phase-modulation index was 1 rad up to about 3 GHz and reduced to 0.5 tad at 7.5 GHz.
TL;DR: The value of the flexibility parameter obtained here showed good agreement with that obtained by the quasielastic light scattering at all temperatures examined and with the binding of heavy meromyosin.
TL;DR: Serum levels of prolactin (PRL) gradually declined in all groups and were not significantly different between the 3 groups, however, significant post-nursing increases in PRL levels were observed 4 days and 6 days after delivery in the good lactation group, and on the 6th postpartum day in the moderate lactationgroup.
Abstract: In order to assess the role of prolactin (PRL) in the initiation oflactation in the early postpartum period, serum levels of PRL in 18 nursing mothers were determined by homologous RIA, near term, immediately after delivery, and before and after a morning nursing on the 2nd, 4th and 6th postpartum day. The mothers were divided into 3 groups (good, moderate and poor lactation) according to the amount of milk produced during the first 5 postpartum days. Basal levels of PRL gradually declined in all groups and were not significantly different between the 3 groups. However, significant post-nursing increases in PRL levels (P < 0.05) were observed 4 days (168%) and 6 days (236%) after delivery in the good lactation group, and on the 6th postpartum day (172%) in the moderate lactation group. But no post-nursing increases were found in the poor lactation group. In order to clarify the cause of different responses of PRL to nursing stimulus, 26 nursing mothers volunteered to have a 20 min breast pump stimulation ...
TL;DR: The extent of the spread of axonal degeneration was investigated in the visual cortex of the cat after making small lesions restricted to the grey matter, with results usually asymmetrical, being greater posteromedially than anterolaterally.
Abstract: The extent of the spread of axonal degeneration was investigated in the visual cortex of the cat after making small lesions restricted to the grey matter. Two series of experiments were undertaken. In the first, normal adult cats were used, and in the second, the cortex of the postlateral gyrus was isolated from its extrinsic afferents by surgical undercutting 3 months before making the lesions. The results were similar in the two series in most respects. 1. Horizontal fibres extended in considerable numbers for some 500 μm from the lesion, mainly in layers I, III/IV and V, a few reaching 2–3 mm. These fibres were better seen in the intact than in the isolated cortex. Their spread was usually asymmetrical, being greater posteromedially than anterolaterally. 2. Oblique axons ran downwards from the middle layers into layers V and VI, or upwards into layers I and II. 3. Axons arising from layers II to VI descended vertically into the white matter. Degeneration patterns after lesions in areas 17 and 18 were compared.
TL;DR: It is suggested that, at least in the reconstituted system, cyt b 5 can play two roles, i.e. improvement of coupling of NADPH oxidation to demethylation, and supply of the second electron to cyt P-450.
TL;DR: In this article, the anodic evolution of oxygen and anodic dissolution of ruthenium have been investigated by means of polarization measurements and product analyses, and the overall current for oxygen evolution is expressed by i = nFka−2H exp (2FE/RT).
TL;DR: In this paper, the authors examined the influence of operating conditions and liquid properties on the frequencies of bubble passing, coalescence and breakup in high speed cinematography and found that there was a critical distance at which the leading bubble began to exert an noticeable influence on the following one.
TL;DR: In this article, isothermal vapor-liquid equilibrium data for the ethane-carbon dioxide system at high pressures were obtained at 10, 15, 18, 20, and 25°C.
TL;DR: It was proved that each revertant was due to a secondary mutation either in the gal80 or GAL81 locus, whereas revertants due to mutation at the supposed controlling site for the structural gene cluster of the galactose-pathway enzymes have not been isolated.
Abstract: Two dominant uninducible mutant alleles in the gal80 locus were identified. The GAL80s-1 and GAL80s-2 mutants showed novel phenotypes in response to the newly isolated GAL81-1 mutant allele, a dominant constitutive mutation linked to the gal4 locus; the GAL80s-1 GAL81-1 strain was inducible and the GAL80s-2 GAL81-1 strain was uninducible. Many galactose positive revertants from the GAL80s-2 GAL81-1 strain were isolated. It was proved that each revertant was due to a secondary mutation either in the gal80 or GAL81 locus, whereas revertants due to mutation at the supposed controlling site for the structural gene cluster of the galactose-pathway enzymes have not been isolated.