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71.
Fujita T Makishima D Akiyama K Hayashi H 《Bioscience, biotechnology, and biochemistry》2002,66(8):1697-1705
New convulsive compounds, brasiliamides A (1) and B (2), were isolated by activity-guided fractionation from okara fermented with a soil isolate of Penicillium brasilianum Batista JV-379. Their structures were elucidated on the basis of spectral and chemical evidence and by X-ray crystallography of the hydrogenated product of 2. In the 1H- and 13C-NMR spectra of 2, the signals were complicated, all being doubled or broadened in several deuterated solvents at room temperature. The conformational change of 2 was clarified as the rotational isomerization of amide bonds in solution by NMR measurements at various temperatures. Four rotamers of 2 at two amide bonds were presented at -60 degrees C in CDCl3, whereas only two isomers were apparent at room temperature, owing to rapid rotation of one of the amide bonds. Brasiliamides A and B respectively showed convulsive activity against silkworms with ED50 values of 300 and 50 microg/g of diet. 相似文献
72.
Matsuda J Takahashi S Ohkoshi K Kaminaka K Kaminaka S Nozaki C Maeda H Tokunaga T 《Cloning and stem cells》2002,4(1):9-19
We produced aggregate chimeric embryos between blastomeres from the somatic cell nuclear transfer (SCNT) embryos and blastomeres from normal embryos. The SCNT embryos were produced by fusing enucleated oocytes with GFP gene introduced fibroblast cells, which were derived from a day 16 fetus. GFP gene-introduced fibroblast cells were cultured and passaged four to 12 times over a period of 45-79 days before SCNT. After transferring them into pseudopregnant recipient rabbits, the 15-day postcoitus fetuses were collected. We examined the existence of the cells derived from SCNT embryos in the fetus stage of pregnancy to detect the GFP gene. Fetuses that were not collected continued to develop into newborn rabbits. Two hundred and thirty-six chimeric embryos were produced using 39 SCNT morula stage embryos, and these embryos were transferred to 11 recipient rabbits. As a result, 27 normally developed and 16 degenerated concepti were obtained. The GFP gene-positive signals were detected in one of the fetuses, two of the placentae, and two of the degenerated concepti. In this study, we found that the rabbit SCNT embryos have the ability to develop and differentiate in vivo. We also demonstrated a novel method of producing a transgenic rabbit using SCNT. 相似文献
73.
Although adaptation to hunting-gathering life is a main hypothesis for understanding of the nature of humans, studies directly examining the hypothesis have not been done. In the present study, we used the method of showing a film depicting hunting and housework by African hunter-gatherers to elementary pupils and university students to examine their memories. In pupils and students, males showed higher percentage of correct answers than females for hunting-related questions, and female showed higher percentage for housework-related questions. The results suggest a males' learning bias to hunting and support the hunting-gathering hypothesis. 相似文献
74.
Momose Y Honda T Inagaki M Shimizu K Irie K Nakanishi H Takai Y 《Biochemical and biophysical research communications》2002,292(1):45-49
We investigated whether and how rat liver thioredoxin reductase spares alpha-tocopherol in biomembranes. Purified hydroperoxides of beta-linoleoyl-gamma-palmitoylphosphatidylcholine were decreased 35% by treatment with thioredoxin reductase and 54% by thioredoxin reductase plus E. coli thioredoxin. Thioredoxin reductase also halved the amount of hydroperoxides that had been formed during photoperoxidation of liposomes composed of beta-linoleoyl-gamma-palmitoylphosphatidylcholine, and of emulsions of both cholesterol and cholesteryl linolenate. In erythrocyte ghosts, thioredoxin reductase spared alpha-tocopherol from oxidation by both soybean lipoxygenase and ferricyanide. Thioredoxin reductase also decreased F(2)-isoprostanes in ghosts oxidized by ferricyanide, suggesting that its ability to spare alpha-tocopherol relates to reduction of lipid hydroperoxides. 相似文献
75.
76.
Johnson DW Trinh MU Oe T 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2003,798(1):159-162
High pressure liquid chromatography with a narrow bore C8 column has been used to separate pristanic, phytanic and very long chain fatty acids, important in the diagnosis of peroxisomal disorders, for their accurate isotope dilution quantification by tandem mass spectrometry. The fatty acids, isolated from plasma, were analysed as trimethylaminoethyl ester (quaternary ammonium) derivatives. Analysis time was 2.5 h and sample requirement was 10 microl of plasma. Good agreement with GC-MS methods for the levels of pristanic and phytanic acids, C26:0/C22:0 and C24:0/C22:0 ratios were obtained for 12 plasma samples from peroxisomal disorder patients and a set of controls. 相似文献
77.
We have applied in vivo intracellular antibody capture (IAC) technology to isolate human intrabodies which bind to the oncogenic RAS protein. IAC facilitates the capture of antibody fragments, in this case single-chain Fvs (scFvs), which tolerate reducing environments, such as the cytoplasm of cancer cells. Three anti-RAS scFvs with different affinity, solubility and intracellular binding activity were characterized. The anti-RAS scFvs with highest affinity were expressed relatively poorly in mammalian cells, and greater soluble expression was achieved by mutating the antibody framework to canonical consensus scaffolds, previously derived from IAC, without losing antigen specificity. Mutagenesis experiments showed that the consensus scaffolds are functional as intrabody fragments without an intra-domain disulfide bond. Furthermore, we could convert an intrabody which does not bind RAS in mammalian cells into a high-affinity reagent capable of inhibiting RAS-mediated NIH 3T3 transformation by exchanging VH and VL complementarity-determining regions onto its consensus scaffold. These data show that the consensus scaffold is a robust framework by which to improve intrabody function. 相似文献
78.
We describe a new enzymatic reaction method for the preparation of the radioisotope-labeled cytokinins isopentenyladenine
(iP), trans-zeatin (tZ), and their ribosides. The method is based on the three enzyme activities of an adenylate isopentenyltransferase
(IPT; EC 2.5.1.27) from Arabidopsis thaliana, an alkaline phosphatase (EC 3.1.3.1) from calf intestine, and a purine-nucleoside phosphorylase (EC 2.4.2.1) from Escherichia coli. The A. thaliana IPT, AtIPT7, utilized both dimethylallyldiphosphate and 4-hydroxy-3-methyl-2-(E)-butenyl diphosphate as isoprenoid donors. The dual specificity of the substrates enabled us to produce iP-type and tZ-type
cytokinins separately in the same system simply by switching the substrates. Our method affords a much higher yield of the
labeled products than the chemical reaction methods previously used. These labeled compounds will be useful tools for cytokinin
research, such as receptor–ligand assays and cell metabolism studies. 相似文献
79.
A critical role for a Rho-associated kinase, p160ROCK, in determining axon outgrowth in mammalian CNS neurons 总被引:19,自引:0,他引:19
Bito H Furuyashiki T Ishihara H Shibasaki Y Ohashi K Mizuno K Maekawa M Ishizaki T Narumiya S 《Neuron》2000,26(2):431-441
We tested the contribution of the small GTPase Rho and its downstream target p160ROCK during the early stages of axon formation in cultured cerebellar granule neurons. p160ROCK inhibition, presumably by reducing the stability of the cortical actin network, triggered immediate outgrowth of membrane ruffles and filopodia, followed by the generation of initial growth cone-ike membrane domains from which axonal processes arose. Furthermore, a potentiation in both the size and the motility of growth cones was evident, though the overall axon elongation rate remained stable. Conversely, overexpression of dominant active forms of Rho or ROCK was suggested to prevent initiation of axon outgrowth. Taken together, our data indicate a novel role for the Rho/ROCK pathway as a gate critical for the initiation of axon outgrowth and the control of growth cone dynamics. 相似文献
80.
Increase in Alkaline Phosphatase Activity in Cucumber Roots during Calcium Starvation 总被引:1,自引:0,他引:1
Alkaline phosphatase activity in cucumber roots increased withcalcium deficiency. However, acid phosphatase was scarcely affectedby the treatment. Re-addition of calcium not only suppressedthe continuous increase in alkaline phosphatase activity butalso reduced the already formed activity. Alkaline phosphatase activity increased with a deficiency ofcalcium, phosphate, minor elements and iron in this order. Eithercycloheximide or actinomycin D completely suppressed the increasein the activity caused by calcium deficiency. (Received April 16, 1981; Accepted July 17, 1981) 相似文献