Showing papers by "University of Tsukuba published in 1987"
TL;DR: It is concluded that spinal neurones with N-methyl-D-aspartate (NMDA) receptors are involved in producing locomotor activity in the rat and that each spinal half can generate hindlimb locomotion on the ipsilateral side.
357 citations
TL;DR: In this article, a longitudinal sediment sorting produced a rhytmic fluctuation in the bedload transposition of two different sized materials were continuously fed into a flume, in which two different sizes of sediment were fed into the flume.
Abstract: Laboratory experiments, in which two different sized materials were continuously fed into a flume, revealed that a longitudinal sediment sorting produced a rhytmic fluctuation in the bedload transp...
249 citations
TL;DR: In this paper, the crystallography of the cubic-to-monoclinic stress-induced martensitic transformation in a Ti-49.8at%Ni alloy was studied using single crystals.
223 citations
TL;DR: It is found that the higher the homology of a candidate donor site sequence to the nine-nucleotide consensus sequence, the higher is its probability of being a donor site and the surrounding nucleotide sequence alone is not generally sufficient for the selection.
219 citations
TL;DR: DAF, which associates with C4b and C3b in the membrane, acts on C2a and Bb, but not on intact C2 and B, and dissociates them rapidly from the binding sites, thereby preventing the assembly of the classical and alternative pathways C3 convertases.
Abstract: DAF is a 70,000-Mr membrane protein that inhibits the amplification of the complement cascade on the cell surface, and protects cells from damage by complement. The precise mechanism of action of DAF is not entirely clear. Purified DAF was incorporated into the membrane of EAC4b cells. EAC4b2 and EDAF AC4b2 cells were prepared with radiolabeled C2. The same amount of labeled C2 bound to both cells, showing that DAF does not prevent the binding of C2 zymogen to C4b. After adding Cl, the radioactivity of bound C2 dissociated more rapidly from EDAF AC4b cells than from EAC4b cells. In EAC4b cells, bound C2 was converted to C2a, which gradually dissociated into the supernatants. In the DAF-treated cells, on the other hand, a large amount of C2a rapidly appeared in the supernatants and only a small amount of C2a remained on the cells. In a similar experiment using EhuAC4b, DAF on human erythrocyte membrane also dissociated the C2a from the cells. These results were confirmed by hemolytic assay and the accelerated decay of C2a caused the rapid depletion of C2 from the fluid phase. In addition, we found that DAF functions on the alternative pathway C3 convertase, C3bBb in the same manner. Thus, DAF, which associates with C4b and C3b in the membrane, acts on C2a and Bb, but not on intact C2 and B, and dissociates them rapidly from the binding sites, thereby preventing the assembly of the classical and alternative pathways C3 convertases.
208 citations
TL;DR: A multi-domain folding model of myOSin head is proposed on the basis of the conserved sequences, information on the topography of myosin in the literature, and the predicted secondary structures.
183 citations
TL;DR: In this article, the inhibition of β-glucosidase by natural polyphenolic substrates is described and the kinetic data suggest that the pattern of inhibition is variable.
181 citations
TL;DR: The crystal structure of the high-temperature form of Ba2YCu3O7-x was refined by the Rietveld analysis of TOF neutron powder diffraction data taken at 49 K as discussed by the authors.
Abstract: The crystal structure of the high-temperature form of Ba2YCu3O7-x was refined by the Rietveld analysis of TOF neutron powder diffraction data taken at 49 K. This compound is tetragonal with lattice constants a = 3.8533 A and c = 11.7631 A. It has an oxygen-deficient triperovskite structure, in which oxygen atoms on a z = 1/2 plane are missing, an oxygen site at (0, 1/2, 0) is about 9% occupied, and Ba2+ and Y3+ ions are completely ordered in a [Ba-Y-Ba]∞, sequence along the c axis.
159 citations
TL;DR: The developmental process of the monosynaptic reflex pathway was investigated morphologically and electrophysiologically in isolated lumbar spinal cords of new‐born and fetal rats, indicating the onset of excitatory post‐synaptic potentials in motoneurones.
Abstract: 1. The developmental process of the monosynaptic reflex pathway was investigated morphologically and electrophysiologically in isolated lumbar spinal cords of new-born and fetal rats. 2. Dorsal root fibres were stained with horseradish peroxidase in the fourth lumbar (L4) segment at different ages ranging from embryonic day (E) 15.5 to post-natal day (P) 0. At E15.5, several collaterals issued from axons in the dorsal funiculus and reached the dorsal part of the dorsal horn. At E16.5, the number of collaterals entering the grey matter increased. Also, a group of collaterals extended ventralwards forming a bundle, and reached the intermediate region. At E17.5, a small number of collaterals reached the motor nuclei. The number of collaterals entering the motor nuclei increased almost linearly with age: 0 at E15.5 and at E16.5, 27 at E17.5, 184 at E18.5, 432 at E19.5 and 746 at P0. 3. The tips of collaterals and their branches had growth cones, boutons (round or oval varicosities) or other varicosities. The mean number of branches with these structures per collateral in the motor nuclei was 1.2 at E17.5, 2.5 at E18.5, 3.6 at E19.5 and 5.8 at E20.5. 4. The percentage of collaterals having growth cones in the motor nuclei was 75% at E17.5, 70% at E18.5, 38% at E19.5 and 15% at E20.5. 5. The mean number of boutons per collateral in the motor nuclei was 0.6 at E17.5, 3.2 at E18.5, 4.9 at E19.5 and 10.7 at E20.5. This increase with age was caused by both branching of collaterals and the increase in the number of boutons of the en passant type. The estimated total number of boutons in the motor nuclei of the L4 segment steeply increased after E17.5: 16 at E17.5, ca. 600 at E18.5, ca. 2000 at E19.5 and ca. 8000 at E20.5-P0. 6. Stimulation of the L4 dorsal root evoked a reflex response in the L4 ventral root, recorded as the ventral root potential, in two out of nine preparations at E15.5 and in all preparations at and after E16.5. The onset of the ventral root potential indicated the onset of excitatory post-synaptic potentials in motoneurones. The segmental latency of the ventral root potentials was markedly shortened between E17.5 and E18.5 (from 12.5 to 7.2 ms) and essentially unchanged at the later stages. 7. The magnitude of monosynaptic reflex responses in the L4 segment gradually increased with age during prenatal stages, becoming maximal at P2-3 and then decreased at the following stages (P4-P8).(ABSTRACT TRUNCATED AT 400 WORDS)
158 citations
TL;DR: Results indicate that the enhanced activity of the ASC system increases the level of intracellular glutathione in the presence of cysteine.
Abstract: Cysteine and cystine transport activities of resting and activated mouse spleen lymphocytes were characterized in order to examine the contributions of cysteine and cystine to intracellular glutathione contents. Following stimulation with lipopolysaccharide, the lymphocytes markedly increased their capacity to transport cysteine. The uptake of cysteine was mediated mainly by the ASC system (Na+-dependent neutral amino acid transport system especially reactive with alanine, serine, and cysteine). On the other hand, both the resting and the activated lymphocytes had extremely low cystine transport activities. Because of the instability of cysteine, the culture media usually contained cystine but not cysteine. Therefore, both the resting and the activated lymphocytes rapidly decreased their glutathione contents owing to their poor capacities to take up cystine. The effects of freshly added cysteine on the cellular glutathione contents were examined in the presence of bathocuproinedisulfonate, a nontoxic copper-specific chelator that inhibits autoxidation of cysteine. Cysteine added at 25-400 microM only partially prevented the rapid decrease of the glutathione contents in fresh resting lymphocytes. In the lipopolysaccharide-activated cells, however, cysteine enhanced the cellular glutathione contents in a dose-dependent manner. These results indicate that the enhanced activity of the ASC system increases the level of intracellular glutathione in the presence of cysteine.
157 citations
TL;DR: A new epithelial cell line, TSU-Pr1, from a human prostatic adenocarcinoma metastatic to lymph node has been established in long term tissue culture and demonstrated an aneuploid karyotype with a modal chromosome number of 80 including a Y-chromosome and at least 10 marker chromosomes.
TL;DR: In this paper, the crystal structure of a high Tc superconductor, Ba2YCu3O7-x, has been refined by the Rietveld analysis of TOF neutron powder diffraction data.
Abstract: The crystal structure of a high Tc superconductor, Ba2YCu3O7-x, has been refined by the Rietveld analysis of TOF neutron powder diffraction data. Two polymorphs of Ba2YCu3O7-x are contained in the sample: orthorhombic (74%) and tetragonal (26%) forms. The two forms have nearly the same structure closely related to that of perovskite-type compounds. In the orthorhombic form, the occupation factor of an oxygen atom on the a axis differed greatly from that on the b axis, which is the main reason why Ba2YCu3O7-x crystallizes in the orthorhombic form.
TL;DR: In this article, the magnetic properties of the heavy fermion state of CeCu 6 were investigated and the Hall coefficient was found to be almost independent of the cerium concentration.
TL;DR: Nineteen physiologically identified group Ia and five group Ib fibers at the L3 and L4 levels of the spinal cord originating from various hind‐limb muscles were intraaxonally injected with horseradish peroxidase (HRP) and the trajectories of the stained axons were reconstructed.
Abstract: Nineteen physiologically identified group Ia and five group Ib fibers at the L3 and L4 levels of the spinal cord originating from various hind-limb muscles were intraaxonally injected with horseradish peroxidase (HRP). The trajectories of the stained axons were reconstructed. They extended for distances of 8.6 mm-18.0 mm rostrocaudally. Ascending axons ran in various regions of the dorsal funiculus: The ascending axon from a toe muscle (3 microns in diameter) ran in the ventral most part of the paramedian region; those from shank muscles (3.0-5.0 microns) in both dorsal and ventral paramedian regions; those from thigh muscles (5.0-7.0 microns) in both the paramedian and the more lateral regions; and those from hip muscles (6.0-7.0 microns) in the lateral region. Main collaterals arising from the parent fiber were given off at intervals of 0.5-6.2 mm (mean 2.4 mm). Collaterals of a fiber from a toe muscle (1.0 micron in diameter) entered Clarke's column from the dorsomedial side and ramified mostly in the dorsomedial one-third of the column. Collaterals of fibers from shank muscles (1.0-2.0 microns) entered Clarke's column from the dorsal side and terminated in its middle parts as well as in laminae V-VII. Collaterals of fibers from thigh muscles (1.0-2.5 microns) passed lateral to or through the lateral part of Clarke's column and terminated in its ventrolateral part and in laminae V-VIII. Collaterals of fibers from hip muscles (1.5-2.5 microns) passed lateral to Clarke's column and ramified mostly in laminae VII-IX. As the muscle of origin became more proximal, the proportion of termination outside of Clarke's column progressively increased. Thus, the trajectory of group I fibers was somatotopically organized both in the dorsal funiculus and in the gray matter. The long axis of boutons ranged from 0.5 to 17 microns in Ia fibers and from 0.5 to 8 microns in Ib fibers. "Giant" Ia boutons (above 7 microns) were found both in and outside Clarke's column.
TL;DR: Systematic QSAR procedures with quantum chemical descriptors were described by showing practical calculations on the inhibition of thiopurine methyltransferase by benzoic acid derivatives, and it was recommended that the A testing routine was introduced into each step to find out multicollinearity.
Abstract: Systematic QSAR procedures with quantum chemical descriptors were described by showing practical calculations on the inhibition of thiopurine methyltransferase by benzoic acid derivatives. In the QSAR analysis, a large number of descriptors relating to reactivity and interaction efficiency are handled, and the collinearities inherently involved among them should be removed to get the stable regression equations. Collinearity was detected by the A value which is the sum of the reciprocals of the eigenvalues of correlation matrix of descriptors divided by the number of descriptors in the equation. In the method of evaluation of all possible equations, the candidate equations selected on the basis of the correlation coefficient with activity and/or predicted sum of square should be examined one by one by the A testing. In the stepwise methods, noncollinear descriptor set is required. The collinearity between two descriptors was removed by a simple method, deleting one of the two descriptors whose correlation is large. It was recommended that the A testing routine was introduced into each step to find out multicollinearity.
TL;DR: In this paper, an advanced synthetic method of highly oriented polyacetylene film has been developed by applying magnetic force into a polymerization system consisting of nematic liquid crystals, which was carried out at 10 − 13°C in order to keep the nematic phase under magnetic field of 2 − 14 kGauss.
TL;DR: It is concluded that actin is present in Tetrahymena, but it is one of the most unique actins among the actins known hereto.
TL;DR: In this article, the number of fast twitch muscle fibers was decreased at age 65 weeks, while the numbers of slow twitch fibers and of alpha motoneurons were decreased only later, at age 135 weeks.
TL;DR: It is found that variation between oak species in leaf tannin levels is positively correlated with 1) variation in the numbers of species of leaf-galling cynipid wasps those trees host; and 2) the density of individual galls per oak leaf.
Abstract: Plant species vary tremendously in the number of phytophagous species they support. May (1979) and Price (1980) proposed that some of this variation may be due to variation in biochemical defenses. We find that variation between oak species in leaf tannin levels is positively correlated with 1) variation in the numbers of species of leaf-galling cynipid wasps those trees host; and 2) the density of individual galls per oak leaf. We hypothesize that leaf and gall tannins serve a protective function for cynipids, decreasing the amount of cynipid larval mortality due to fungal infestation. This defensive function would explain the observed positive relationships between oak tannin levels and cynipid diversity as well as cynipid abundance.
TL;DR: The genus Heterosigma akashiwo is validly desribed by providing a Latin diagnosis and designating a type species and ultrastructural characteristics are also given for the genus.
Abstract: Heterosigma akashiwo and its related algae were re-examined by light and electron microscopes using cultured materials including type cultures of bothH. akashiwo andH. inlandica as well as specimens referred to asOlisthodiscus luteus maintained in CCAP and UTEX. All the strains examined were similar to one another in appearance and ultrastructural features. They can be accommodated in a single species,H. akashiwo, which has been invalidly published.
TL;DR: It seems likely that the organism is an undescribed dinoflagellate containing an endosymbiont with chlorophylls a and b and that the reduction of the endosYMBiont nucleus and mitochondria has permitted a more initmate symbiosis.
Abstract: A green-colored marine unicell has been grown in unialgal culture and its morphology, chloroplast fine structure, and chlorophyll composition investigated. The organism is typical of dinoflagellates in its shape, flagellation, nucleus, mitochondria, and trichocysts. It is similar to Gymnodinium but possesses fine body scales. Chloroplasts and two kinds of vesicles bounded by double membranes, but no organelles obviously identifiable as nuclei or mitochondria, are associated in ribosome-dense cytoplasm separated by a double membrane from the dinophycean cytoplasm. The chloroplasts are unlike any previously reported for dinoflagellates. Each is enclosed by an envelope consisting of a double membrane. Chloroplast lamellae consist of three appressed thylakoids. Interlamellar pyrenoids are present. Pigment analysis reveals chlorophylls a and b but not chlorophyll c. It seems likely that the organism is an undescribed dinoflagellate containing an endosymbiont with chlorophylls a and b and that the reduction of the endosymbiont nucleus and mitochondria has permitted a more initmate symbiosis.
TL;DR: HCO3- is a unique activator in vivo which makes the quiescent sperm motile via the HCO3(-)-adenylate cyclase-cAMP system, to which an endogenous H CO3- derived from metabolic CO2 may be related.
TL;DR: In this article, a novel synthetic method of one-dimensional conjugated polyyne so-called carbyne is presented, which is a dehydrochlorination of stereospecifically chlorinated polyacetylene, (CHCl)x, synthesized through prolonged FeCl3-doping.
TL;DR: In this article, the crystal structure of a Ba-Y-Cu-O superconductor was refined by the Rietveld analysis of X-ray powder diffraction data.
Abstract: The crystal structure of a Ba-Y-Cu-O superconductor was refined by the Rietveld analysis of X-ray powder diffraction data. This material is orthorhombic with lattice parameters a = 3.8845 A, b = 3.8293 A, and c = 11.6926 A. Possible space groups are P222, Pmm2, and Pmmm. Metal atoms have essentially the same configuration as that in the perovskite-type structure. A structural model is proposed in which an oxygen atom at (0, 0, 1/2) is deficient.
TL;DR: The GST1 0 phenotype was found more frequently in livers with hepatitis and carcinoma than in control livers, and was detected as a rare variant allele in patients suffering from various liver diseases.
Abstract: A total of 168 autopsy liver extracts from Japanese individuals were examined for the glutathione S-transferase (GST) isozymes by means of starch gel electrophoresis. The gene frequencies of GST1*1, GST1*2, and GST1*0 in Japanese were 0.252, 0.057, and 0.691, respectively. GST1*3 was detected as a rare variant allele. The incidence of GST1 0 in 41 liver biopsy samples from patients suffering from various liver diseases was investigated using polyacrylamide gel isoelectric focusing. The GST1 0 phenotype was found more frequently in livers with hepatitis and carcinoma than in control livers. The isozymes coded by different GST loci were partially purified and characterized to study their biochemical properties. The apparent Km values with 1-chloro-2,4-dinitrobenzene (CDNB) as substrate for the isozymes at the GST1, GST2, GST3, and GST4 loci were 604, 1345, 776 and 591 μM, respectively.
TL;DR: A toxin, named as cyanoviridin RR, has been isolated from the cyanobacterium Microcystis viridis and the structure of the toxin has been determined by modern NMR techniques such as the HMBC spectrum.
TL;DR: It has been concluded that the NRA expiratory neurons are involved only in spinal action, and that they receive a postsynaptic inhibition during inspiration.
TL;DR: A DNA fragment possessing ORF12 of TL-DNA of Ri(A4) plasmids (Slightom et al. 1986) was inserted into the genome of Nicotiana tabacum cv.
Abstract: A DNA fragment possessing ORF12 of TL-DNA of Ri(A4) plasmids (Slightom et al. 1986) was inserted into the genome of Nicotiana tabacum cv. Petite Havana SR1, through the binary vector system harbored by Agrobacterium tumefaciens. The transformed plants showed dwarfness in plant height and corolla length. Adventitious roots were not induced from leaf disks by A. tumefaciens possessing ORF12.
TL;DR: In this paper, the Raman spectrum of hexagonal BaTiO 3 has been investigated in the temperature range from 2 K to room temperature, and the corresponding underdamped soft-phonon modes were found; the mode frequencies were proportional to (T a - T ) β with β∼ 1/3 in a wide temperature range (0.5 < T / T a < 0.95).
Abstract: The Raman spectrum of hexagonal BaTiO 3 has been investigated in the temperature range from 2 K to room temperature. Below the structural-phase-transition temperature of T a (∼222 K), we find the corresponding underdamped soft-phonon modes; the mode frequencies are proportional to ( T a - T ) β with β∼1/3 in a wide temperature range (0.5< T / T a <0.95). Although, in the ferroelectric phase below T c (∼74 K), several new features are observed, no soft mode which correlates with the ferroelectric transition is found.
TL;DR: Pyridyl Grignard reagents were prepared from the corresponding iodopyridine and EtMgBr using cross coupling reactions on the sulfinyl sulfur atom to afford biazaheteroaryls as discussed by the authors.