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51.
Yukio Takahata Toshikazu Hasegawa Toshisada Nishida 《International journal of primatology》1984,5(3):213-233
Fifty-four episodes of predatory behavior of wild chimpanzees were recorded in Mahale, western Tanzania, from August 1979
to May 1982. The chimpanzees most frequently hunt in two seasons, during May, and from August to December. Longer-term fecal
analysis indicates that predation frequency is significantly higher in the dry than in the rainy season. The seasonality of
predation might be the result of the sum of various ecological factors, at least one of which is the birth season of the prey
species. Most of the prey are juvenile blue duiker, bushbuck, bushpig, red colobus, and red-tailed monkeys. Sex difference
is recognized in the prey selection and in the hunting method employed. Apparent local difference in the predatory behavior
between Mahale and Combe chimpanzees (in Mahale,females hunt more frequently, and blue duiker is the most frequent prey) can be understood in terms of the difference either
in the observation methods or in the faunal diversity and density. Other aspects of predatory behavior also are reported. 相似文献
52.
Two forms of -glucosidase (EC 3.2.1.20), designated as I and II, have been isolated from sugarbeet (Beta vulgaris L.) seeds by a procedure including fractionation with ammonium sulfate and ethanol, carboxymethyl-cellulose column chromatography, and preparative disc gel electrophoresis. The two enzymes were homogeneous by polyacrylamide disc gel electrophoresis. Their molecular weights were 98,000 (I) and 60,000 (II). -Glucosidase I readily hydrolyzed maltose, isomaltose, kojibiose, maltotriose, panose, amylose, soluble starch, amylopectin and glycogen. -Glucosidase II also hydrolyzed maltose, kojibiose and maltotriose but hydrolyzed the other substrates only very weakly or not at all. -Glucosidase I hydrolyzed soluble starch at a faster rate than maltose. It produced isomaltose and panose as the main -glucosyltransfer products from maltose, whereas maltotriose was the main product of -glucosidase II. -Glucosidase I hydrolyzed amylose liberating -glucose. The neutral-sugar content was calculated to be 2.7% for -glucosidase I and 8.8% for -glucosidase II. The main neutral sugar was mannose in -glucosidase I, and glucose in -glucosidase II. 相似文献
53.
Yukio Yamagata Atsunori Yamashita Katsuhiko Inomata 《Origins of life and evolution of the biosphere》1980,10(1):47-50
Di-and tri-glycine were synthesized in 1M aqueous solution of glycine by bubbling for 90 hr with oxygen discharged in the path from an oxygen cylinder. The peptides were also produced by an incubation at 37°C of 2M glycine solution prepared with 75% hydrogen peroxide, and the yields were traced for 200 days. The final yields were about 0.25% and 0.01% for di-and tri-glycine, respectively. The solution at 166 days of incubation was applied to a Sephadex G 10 column, and the fractions around the top of the chromatogram were found to increase the intensity of ninhydrin color about 45 times after hydrolysis, indicating an existence of oligo-glycine. The solutions of 1M glycine and 0.5M diglycine prepared with 30% hydrogen peroxide were incubated at 37°C for 38 days, and di-and tetra-glycine were detected in the yields of 0.12% and 0.33%, respectively. 相似文献
54.
Yukio Yasukochi Richard T. Okita Bettie Sue Siler Masters 《Archives of biochemistry and biophysics》1980,202(2):491-498
NADPH-cytochrome P-450 reductases from pig liver and kidney and rabbit liver microsomes were purified to a specific activity of 50–62 μmol cytochrome c reduced/min/mg. All reductase preparations were separated into one major and one minor fraction on Sephadex G-200 columns. The molecular weights of the major fractions of the reductases were estimated to be 74,000, 75,000, and 75,500 for rabbit liver, pig kidney, and liver reductases, respectively, whereas the molecular weight of the minor fractions of these reductases, 67,000, was the same as that of the steapsin-solubilized pig liver reductase on SDS-polyacrylamide gel electrophoresis. Km values for NADPH and cytochrome c were: 20 and 29 μm or 14 and 28 μm for the pig kidney or liver reductase, respectively. Immunochemical studies, including Ouchterlony double diffusion experiments and inhibition of benzphetamine N-demethylation activity in microsomes by antibody against pig liver NADPH-cytochrome P-450 reductase, indicated the similarity of the purified liver and kidney reductases. There were no differences in the ability to reconstitute NADPH-mediated benzphetamine N-demethylation and laurate hydroxylation in reconstituted systems between the pig liver and kidney reductases, indicating that the reductase did not determine substrate specificity in these systems. 相似文献
55.
The addition reaction to N-methyl-(S)-alanine or N-methyl-(S)-phenylalanine N-car-boxyanhydride (NCA) of 3-methyl-5-substituted hydantoin (HDT) catalyzed by a tertiary amine was investigated as a model reaction for the propagation reaction of NCA according to the activated-NCA mechanism. Several activated HDTs having the (S)-configuration of the asymmetric carbon atom were found to react more rapidly than their activated enantiomers. This experimental result indicates that the enantiomer selection by terminal-unit control takes place in the propagation reaction according to the activated-NCA mechanism in which an activated NCA is added to a terminal acylated NCA ring of the growing chain. The enantiomer excess of the HDT recovered from the reaction mixture of N-methyl-(S)-phenylalanine NCA and racemic HDTs activated by a tertiary amine was determined. The extent of the enantiomer selection in the polymerization was found to be 3–10 times as large as that in the model reaction. From these results, it was concluded that the chirality of the penultimate unit, as well as that of the terminal NCA ring, plays an important role in determining the enantiomer selection in the NCA polymerization. 相似文献
56.
Brenda Walker Griffin Charles Marth Yukio Yasukochi Bettie Sue Siler Masters 《Archives of biochemistry and biophysics》1980,205(2):543-553
Under identical experimental conditions, purified preparations of rabbit liver microsomal cytochrome P-450 and beef heart metmyoglobin were equally effective at stimulating the oxidation of aminopyrine to a free radical species by cumene hydroperoxide. Mannitol had no effect on radical levels produced with either hemeprotein-hydroperoxide system; however, specific ligands of the two hemeproteins, substrates of cytochrome P-450, and phospholipid affected the two systems quite differently. Only the metmyo-globindependent oxidation of aminopyrine was significantly inhibited by fluoride and cyanide. Metyrapone, a specific ligand of cytochrome P-450, and benzphetamine, which was N-demethylated by cumene hydroperoxide only in the presence of cytochrome P-450, inhibited only the cytochrome P-450-stimulated oxidation of aminopyrine. Moreover, only with the solubilized liver hemeprotein was aminopyrine radical generation markedly stimulated by phospholipid. Similar properties of aminopyrine N-demethylation and radical formation by the cytochrome P-450-cumene hydroperoxide system have strongly implicated the radical as a requisite intermediate in product formation. Micromolar concentrations of metyrapone caused parallel inhibition, by at least 50%, of both radical generation and formaldehyde production. These results support a radical pathway of N-demethylation proposed for other hemeprotein-hydroperoxide systems (B. W. Griffin and P. L. Ting, 1978, Biochemistry, 17, 2206–2211), in which the substrate undergoes two successive one-electron abstractions, followed by hydrolysis of the iminium cation intermediate. Thus, for this class of substrates, the experimental data are consistent with the oxygen atom of the product arising from H2O and not directly from the hydroperoxide, which has been previously proposed as a general mechanism for cytochrome P-450 peroxidatic activities. 相似文献
57.
OEP, a component consisting mainly of protein with small amounts of lipids and sugars, has been isolated from the autolysate of Pseudomonas aeruginosa and purified by physicochemical methods. It possesses remarkable biological properties, showing antitumor and interferon-inducing activities. As regards the antitumor activity of the sample, the ED50 value against ascites sarcoma-180 was 1 microgram/kg mouse/day, and its interferon-inducing activity amounted to 15 units at a concentration of 0.01 microgram/ml. Both activities increased after protease digestion, reaching about ten times those of the sample which had not undergone digestion. The protease-treated OEP contained 17% protein, 14.5% total sugars, 31% lipids, 12.5% hexosamine, 3.8% KDO, and 2.7% phosphorus. Neutral sugars consisted of 12.4% rhamnose, 2.7% mannose, 66.9% glucose, and other unidentified material. Total lipids derived from OEP consisted of 65% loosely-bound and 35% covalently-bound lipids; the former contained C14:10, C16:0, C16:1, C18:0, and C15:1 acids and the latter, beta-OH C10:0, C12:0, alpha-OH C12:0, beta-OH C12:0, C16:0, and C16:1 acids. The antitumor and interferon-inducing activities of OEP remained after the removal of loosely-bound lipids from OEP. 相似文献
58.
Seed germination and further growth of seedlings of an obligate root parasiteAeginetia indica L. are described. (1) Germination: dormancy of fresh seeds can be broken by sodium hypochlorite treatment, but seeds stored for 1–5 years at 5 C did not necessarily require halogen treatment for good germination. (2) Formation of the tendril, which facilitated the organic connection with the host, was stimulated greatly byMiscanthus root extract. (3) Septation (cell division) of tendril was promoted by addition of sucrose to the basal medium. (4) Rhizogenesis of the seedlingin vitro was stimulated by deproteinized coconut milk. 相似文献
59.
Addition of antibodies against sapecin to the culture medium of NIH-Sape-4 cells derived from a Sarcophaga embryo greatly inhibited cell proliferation, whereas addition of sapecin stimulated cell proliferation. These results suggest that sapecin is involved in the proliferation of embryonic cells of Sarcophaga. Sapecin is known to have potent antibacterial activity, so it seems to have two different biological functions: i.e. protection against bacterial infection and stimulation of embryonic cell proliferation. 相似文献
60.
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