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81.
Specific binding of radiolabeled L-glutamic acid (Glu) was examined using rat brain synaptic membranes treated with a low concentration of Triton X-100. The binding drastically increased in proportion to increasing concentrations of the detergent used up to 0.1%. Addition of 100 mM sodium acetate significantly potentiated the binding in membranes not treated with Triton X-100, whereas it markedly inhibited the binding in Triton-treated membranes. The binding in Triton-treated membranes was inversely dependent on incubation temperature and reached a plateau within 10 min after the initiation of incubation at 2 degrees C, whereas the time required to attain equilibrium at 30 degrees C was less than 1 min. Sodium acetate invariably inhibited the binding detected at both temperatures independently of the incubation time via decreasing the affinity for the ligand. The binding was significantly displaced by agonists and antagonists for an N-methyl-D-aspartate (NMDA)-sensitive subclass of brain excitatory amino acid receptors, but not by those for the other subclasses. Inclusion of sodium acetate reduced the potencies of NMDA agonists to displace the binding without virtually affecting those of NMDA antagonists. Moreover, sodium ions inhibited the ability of Glu to potentiate the binding of N-[3H] [1-(2-thienyl)cyclohexyl]piperidine to open NMDA channels in Triton-treated membranes. These results suggest that sodium ions may play an additional modulatory role in the termination process of neurotransmission mediated by excitatory amino acids via facilitating a transformation of the NMDA recognition site from a state with high affinity for agonists to a state with low affinity. 相似文献
82.
Yukio Fukui Kenji Gushima Shunpei Kakuda Hiroaki Hashimoto 《Ichthyological Research》1991,37(4):395-401
Coloration and sex change were studied in a temperate wrasseHalichoeres poecilopterus in the central part of the Seto Inland Sea, Japan. 1,270 examples, 45–179 mm SL, were collected from May to December both
in 1983 and 1984. The species is a diandric, protogynous hermaphrodite, and has three color patterns: pale color type (A),
brilliant color type (B) and intermediate color type (AB). A-fish were less than 142 mm SL and consisted of primary males
(42.6%), females (55.4%), secondary males (0.3%) and fish with transitional gonads (1.7%). A-females changed their color to
B, through AB, in the size range 101–131 mm SL. A-primary males changed their color to B, through AB, in the size range 103–134
mm SL. B-fish consisted of primary males (38.6%), secondary males (54.6%) and fish with transitional gonads (6.8%). The majority
of females changed their sex to male in the size range 98–131 mm SL. 相似文献
83.
Naoki Koyama Yukio Takahata Michael A. Huffman Koshi Norikoshi Hisayo Suzuki 《Primates; journal of primatology》1992,33(1):33-47
Over a 30-year period from 1954 to 1983, 975 live births were recorded for Japanese macaque females at the Iwatayama Monkey
Park, Arashiyama, Japan. Excluding unknown birth dates, primiparous mothers gave birth to 185 infants (182 cases with age
of mother known) and multiparous mothers gave birth to 723 infants (603 cases with age of mother known). The peak month of
birth was May with 52.3% of the total births occurring during the period. Multiparous females who had not given birth the
previous year did so earlier than multiparous females who had given birth the previous year and also earlier than primiparous
females. Among the females who had given birth the previous year, females whose infant had died gave birth earlier than females
who had reared an infant the previous year. The offspring sex ratio (1:0.97) was not significantly different from 1:1, and
revealed no consistent association with mother's age. Age-fecundity exhibited a humped curve. The annual birth rate was low
at the age of 4 years but increased thereafter, ranging between 46.7% and 69.0%, at between 5 and 19 years of age, but again
decreased for females between 20 and 25 years of age. Some old females displayed clear reproductive senescence. The infant
mortality within the first year of age was quite low (10.3%) and the neonatal (less than 1 month old) mortality rate accounted
for 49.0% of all infant deaths. There was no significant difference between the mortality rates of male and female infants.
A female's rank-class had no apparent effect on the annual birth rate, infant mortality, and offspring sex ratio. These long-term
data are compared with those from other primate populations. 相似文献
84.
Summary Lipase was modified with several hydrophilic and hydrophobic synthetic polymers. The modified lipase was solubilized into chloroform by. The catalytic esterification activity of modified lipase increased linearly with the increase of its solubility in chloroform. 相似文献
85.
Toshio Sugimoto Tsutomu Kawasaki Tomohiko Kato Robert F. Whittier Daisuke Shibata Yukio Kawamura 《Plant molecular biology》1992,20(4):743-747
A full-length cDNA encoding a subunit of phosphoenolpyruvate carboxylase (PEPC) was isolated from a developing seed expression library of the C3 plant Glycine max. The corresponding mRNA is present at similar levels in leaf, stem, root and developing seed. Two potential start codons exist, and the activity of protein initiated from the first such codon could be subject to regulation by protein kinase. Sequence comparison shows a similar upstream start codon in the case of the Ppc2 gene from Mesembryanthemum crystallinum, previously assumed to lack the sequences necessary for phosphorylation. The soybean encoded protein tends to resemble other C3-type PEPC proteins more closely than those implicated in C4 or crassulacean acid metabolism. 相似文献
86.
Nobutoshi Baba Hiroyuki Kawami Yukio Sato Takahiro Takayama Tetsuya Toge 《Biotherapy》1991,3(4):359-364
The enhancement of antitumor activities of the tumoricidal soluble factor (SF) from a streptococcal preparation (OK-432)-activated macrophages by the pretreatment with a protein-bound polysaccharide (PSK) was investigated in tumor-bearing mice.Two-step stimulations with OK-432 atin vivo priming andin vitro eliciting were required for the production of the tumoricidal SF by macrophages, and the tumoricidal activity of the SF apparently correlated with the uptake of OK-432 by macrophages at priming phase.Tumoricidal activity of the SF from OK-432-activated macrophages in proteose-peptone (P-P)-pretreated mice significantly decreased with the development of the tumor, whereas in PSK-pretreated mice did not. Pretreatment of tumor-bearing mice with PSK saved a decrease in the macrophages carrying Iak or asialo GM1 antigens and an increase in wheat germ agglutinin (WGA) receptors. Furthermore, the uptake of OK-432 by macrophages at priming phase was enhanced. The tumoricidal activity of the SF from OK-432-activated macrophages was augmented.Thus, PSK may restore the depressed functions of macrophages, and the combination therapy with PSK and OK-432 may be effective to enhance the production of tumoricidal SF in tumor-bearing mice. 相似文献
87.
Jang-Su Park Katsuhiro Kano Yukio Morimoto Yoshiki Higuchi Noritake Yasuoka Mari Ogata Katsumi Niki Hideo Akutsu 《Journal of biomolecular NMR》1991,1(3):271-282
Summary The1H NMR signals of the heme methyl, propionate and related chemical groups of cytochromec
3 fromDesulfovibrio vulgaris Miyazaki F (D.v. MF) were site-specifically assigned by means of ID NOE, 2D DQFCOSY and 2D TOCSY spectra. They were consistent with the site-specific assignments of the hemes with the highest and second-lowest redox potentials reported by Fan et al. (Biochemistry,29 (1990) 2257–2263). The site-specific heme assignments were also supported by NOE between the methyl groups of these hemes and the side chain of Val18. All the results contradicted the heme assignments forD.v. MF cytochromec
3 made on the basis of electron spin resonance (Gayda et al. (1987)FEBS Lett.,217 57–61). Based on these assignments, the interaction of cytochromec
3 withD.v. MF ferredoxin I was investigated by NMR. The major interaction site of cytochromec
3 was identified as the heme with the highest redox potential, which is surrounded by the highest density of positive charges. The stoichiometry and association constant were two cytochromec
3 molecules per monomer of ferredoxin I and 108 M–2 (at 53 mM ionic strength and 25°C), respectively. 相似文献
88.
Specific pathogen free BALB/c mice from 3 commercial laboratory animal breeders in Japan were compared on the composition of caecal flora revealed by selective and nonselective cultivation as well as direct microscopical observation on smears, and relative caecal weight. Large differences were detected in viable counts of total bacteria and almost all bacterial groups, while direct microscopical counts which consisted mainly of fusiform bacteria were almost equal, resulting in diverse recovery rates among 3 breeders. Eubacterium and spiral shaped organisms were not detected from all breeders. There also existed variations within breeders, especially those in the number of Enterobacteriaceae. Relative caecal weight also differed among breeders, suggesting the participation of variety of caecal bacteria in determining this parameter. As these variations in bacteriological status of animals can influence experimental results, standardization of intestinal microbial flora is required. 相似文献
89.
Hiroshi Kato Taiji Kato Yukio Sakazaki Yosuke Yamakawa Nobuyuki Naganawa Junichi Funabiki Takasumi Kato Ryo Tanaka Akira Masaoka Hidehiko Tsunooka 《Neurochemistry international》1982,4(5):419-426
BL191, a newly developed phosphodiesterase inhibitor, markedly potentiated a differentiation of neuroblastoma cell clones (Neuro2a, NS-20Y, and N1E115) induced by dibutyryl cyclic adensoine 3′:5′-monophosphate(dibutyryl cAMP) and prostaglandin E1 (PGE1). BL191 (1 mM) inhibited DNA synthesis more strongly when used together with PGE1 (0.5 μg/ml) and dibutyryl cAMP (0.5 mM) than papaverine (1.6 μg/ml) alone did. The inhibition rates of DNA synthesis were 72.5% for N1E-115, 75.3% for Neuro2a, and 82.5% for NS-20Y. After the treatment with BL191. PGE1, and dibutyryl cAMP for 48 h all of three cell lines became enlarged and flattened, and extended long processes. The specific activities of choline acetyl transferase (EC 2.3.1.9) of NS-20Y and dopamine β-hydroxylase (EC 1.14.17.1) of N1E-115 increased about 3-fold as compared to the controls. The tumorigenicities of Neuro2a and N1E-115 cells were decreased, but not of NS-20Y. These data suggest the heterogenous responsiveness in neuroblastoma cells to drug treatment. 相似文献
90.
Shigetaka Kitajima Yukio Yasukochi Shigeki Minakami 《Archives of biochemistry and biophysics》1981,210(1):330-339
An NADH:(acceptor) oxidoreductase (EC 1.6.99.3) of human erythrocyte membrane was purified by DEAE-cellulose anion exchange, hydroxyapatite adsorption, and 5′-ADP-hexane-agarose affinity chromatographies after solubilization with Triton X-100. The purified reductase preparation was homogeneous and estimated to have an apparent molecular weight of 36,000 on SDS-polyacrylamide slab gel electrophoresis and of 144,000 on Sephadex G-200 gel filtration in the presence of 0.2% Triton X-100, whereas a soluble NADH-cytochrome b5 reductase of human erythrocyte had a molecular weight of 32,000 by both methods, indicating the existence of a distinct membrane reductase. Digestion of the membrane reductase with cathepsin D yielded a new polypeptide chain which gave the same relative mobility as the soluble reductase on SDS-polyacrylamide slab gel electrophoresis. The membrane enzyme, the cathepsin-digested enzyme, and the soluble enzyme all cross-reacted with the antibody to rat liver microsomal NADH-cytochrome b5 reductase. The enzyme had one mole FAD per 36,000 as a prosthetic group and could reduce K3Fe(CN)6, 2,6-dichlorophenolindophenol, cytochrome c, methemoglobin-ferrocyanide complex, cytochrome b5 and methemoglobin via cytochrome b5 when NADH was used as an electron donor. NADPH was less effective as an electron donor than NADH. The specific activity of the purified enzyme was 790 μmol ferricyanide reduced min?1 mg?1 and the turnover number was 40,600 mol ferricyanide reduced min?1 mol?1 FAD at 25 °C. The apparent Km values for NADH and cytochrome b5 were 0.6 and 20 μm, respectively, and the apparent V value was 270 μmol cytochrome b5 reduced min?1 mg?1. These kinetic properties were similar to those of the soluble NADH-cytochrome b5 reductase. The results indicate that the NADH:(acceptor) oxidoreductase of human erythrocyte membrane could be characterized as a membrane NADH-cytochrome b5 reductase. 相似文献