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41.
Tatsuhide Kunishita Takeshi Tabira Hidehiko Umezawa Makoto Mizutani Yasutomi Katsuie 《Journal of neurochemistry》1986,46(1):105-111
Biochemical and morphological studies were done on a new trembling mutant hamster CBB. The yield of myelin from the mutant was 30 and 40% of the control at 46 and 140 days of age, respectively, but myelin composition and 2',3'-cyclic nucleotide-3'-phosphohydrolase (CNPase) activity were normal. Morphologically, about 18% of the axons were myelinated in the mutant optic nerve at 46 days of age, in which the myelinated fibers were those with larger diameters (more than 0.6 micron), while the control had a peak at 0.4 micron in diameter. The ultrastructure and thickness of compact myelin lamellae in the mutant were normal. Myelination and the structure of peripheral nerve myelin appeared normal. The results indicate that the essential defect is the delay and arrest of myelination in the CNS, which is probably caused by either a decreased rate of synthesis of myelin components in oligodendrocytes or a defect in the oligodendrocyte-axon recognition in smaller axons. 相似文献
42.
43.
Tajima Shigeyuki; Kanazawa Takeshi; Takeuchi Eiko; Yamamoto Yukio 《Plant & cell physiology》1985,26(5):787-795
The cadaverine content of soybean radicles showed a maximumpeak 34 days after planting. The variation coincidedwith radicle uricase activity during seed germination. The uricase activity could not be fractionate when the bufferpH for the extraction was at 6.0. The addition of 1 M KCl orNaCl to the buffer allowed the extraction of the uricase activity,but an addition of 1 M MgCl2 or BaCl2 inhibited this enzyme'sactivity. The urate-degrading enzyme system was purified 248-fold permilligram of protein from soybean radicles. The respective Kmvalues of the diamine oxidase activity for cadaverine and ofthe urate-degrading activity for hydrogen peroxide and uratewere 1.25, 2.93 and 50.3 µM. Analysis by gel electrophoresisof the partially purified enzyme fraction revealed that theurate-degrading enzyme system consisted of a peroxidase thatdegrades urate with hydrogen peroxide and a diamine oxidasethat releases hydrogen peroxide. These data are evidence that a urate-degrading diamine oxidaseand peroxidase system exists in soybean radicles and that thereaction rate of urate-degradation is controlled by the concentrationof cadaverine. (Received November 28, 1984; Accepted April 8, 1985) 相似文献
44.
Inhibition of photosynthesis by Na2SO3 in mesophyll protoplastsisolated from Vicia faba leaves and uptake of sulfite by theprotoplasts were examined at various pH values of the incubationmedium containing Na2SO3. As the pH of the incubation mediumlowered, the rate of photosynthesis in the protoplasts decreasedand the amount of sulfite taken up by the protoplasts increased.Most of sulfite accumulated in the protoplasts was not metabolizedduring the dark incubation, as measured with an ion chromatograph.Photosynthetic O2 evolution by the chloroplasts isolated fromVicia mesophyll protoplasts was inhibited by exogenously-appliedNa2SO3 over pH region examined (7.49.0). The sulfiteconcentration required for a half inhibition of photosynthesisby the isolated chloroplasts was similar to the intracellularsulfite level required for that by the protoplasts. These resultsindicate that the intracellular sulfite accumulated in the protoplastsin an unmetabolized state is responsible for the inhibitionof protoplast photosynthesis. (Received January 24, 1985; Accepted May 29, 1985) 相似文献
45.
Induction of peroxisomal beta-oxidation enzymes in primary cultured rat hepatocytes by clofibric acid 总被引:1,自引:0,他引:1
Rat hepatocytes were cultured for 72 h with or without the addition of 0.5 mM clofibric acid. The activities of individual enzymes of the peroxisomal beta-oxidation pathway (acyl-CoA oxidase, enoyl-CoA hydratase-3-hydroxyacyl-CoA dehydrogenase bifunctional protein, and 3-ketoacyl-CoA thiolase) decreased in the control culture, but markedly increased synchronously in the clofibric acid-treated culture. The levels of mRNAs coding for these enzymes and the rates of synthesis of the enzymes were also elevated in the clofibric acid-treated culture, although no proportional relationship was observed between the time-dependent changes of these parameters. The increase in mRNAs was much higher than the increase in the rate of synthesis of the enzymes. The activity of catalase, its mRNA level and the rate of its synthesis were slightly affected. The effects of clofibric acid on the peroxisomal beta-oxidation enzymes and catalase in primary cultured hepatocytes were very similar to those observed in vivo. These results, therefore, suggest that primary culture of hepatocytes should provide a useful means for investigating the mechanism of induction of peroxisomal enzymes and the mechanism of action of peroxisome proliferators. 相似文献
46.
Molecular cloning and nucleotide sequence of the cDNA for rat peroxisomal enoyl-CoA: hydratase-3-hydroxyacyl-CoA dehydrogenase bifunctional enzyme 总被引:17,自引:0,他引:17
T Osumi N Ishii M Hijikata K Kamijo H Ozasa S Furuta S Miyazawa K Kondo K Inoue H Kagamiyama 《The Journal of biological chemistry》1985,260(15):8905-8910
For the studies on the mechanism of induction of peroxisomal beta-oxidation enzymes and biogenesis of the organelle, we have isolated cDNA clones for rat peroxisomal enoyl-CoA: hydratase-3-hydroxyacyl-CoA dehydrogenase bifunctional enzyme. On blotting experiments with liver RNA, the cDNAs hybridized to a 3.0-kilobase RNA which was increased 5-7-fold by the administration of di-(2-ethylhexyl)phthalate to rats. Nucleotide sequencing was carried out for four cloned cDNAs and one obtained by a primer extension method. By overlapping these sequences with each other, we identified 20 nucleotides of 5'-noncoding, 2,166 nucleotides of coding, and 910 nucleotides of 3'-noncoding regions. The deduced amino acid sequence of the enzyme is composed of 722 residues, and the composition agrees with that of the protein data. The sequence was confirmed by the amino acid compositions and sequence analyses of some of the tryptic peptides. The molecular weight of the mature enzyme is calculated to be 78,511 from the predicted amino acid sequence. The enzyme has no terminal peptide extension as a signal for translocation into peroxisomes. 相似文献
47.
48.
Tomoshiro Takeda Osamu Ueno Muneaki Samejima Takeshi Ohtani 《Journal of plant research》1985,98(4):393-411
Two hundred and twenty species of 38 genera in the Cyperaceae from Australia were examined for the possible occurrence of the C4 photosynthesis and the anatomical features of leaves and culms. The Kranz type of anatomy and the carbon isotope ratios typical of C4 plants were found in 84 species in the following six genera of four tribes belonging to subfamily Cyperoideae:Bulbostylis, Crosslandia, andFimbristylis (Fimbristylideae);Lipocarpha (Lipocarpheae);Cyperus (Cypereae);Rhynchospora (Rhynchosporeae). The anatomical observation revealed that the C4 species possessed any one of the three Kranz anatomical types found by previous investigators. It was suggested that in the Cyperaceae the C4 syndrome evolved independently within several taxa of the subfamily. The relative distribution of C3 and C4 species of the Cyperaceae in Australia was investigated by use of floristic data. It was recognized that the C4 species dominated in the northern part of the continent which was characterized by tropical and subtropical savannas and hot dry areas with summer rainfall, and the C3 species in the southern part, which contained temperate areas and mediterranean climatic areas with winter rainfall. 相似文献
49.
In an attempt to elucidate the relationship between phosphatidylinositol breakdown and alpha-adrenergic responses, effects of phosphatidic acid and phosphatidylinositol related metabolites on Ca2+ mobilization and glucose output in cultured hepatocytes were examined. Norepinephrine induced the net 45Ca2+ efflux from preloaded cells and stimulated glucose output via alpha-adrenergic receptor stimulation, whereas phosphatidic acid caused 45Ca2+ uptake to cells and did not stimulate glucose output. Myo-inositol-monophosphate, diglyceride and arachidonic acid, which are released by phosphatidylinositol breakdown, had no effect on 45Ca2+ efflux and glucose output in cells. These results suggest that phosphatidic acid and phosphatidylinositol related metabolites can not mimic the alpha-adrenergic actions in cultured hepatocytes. 相似文献
50.
Spores of Nosema bombycis derived from diseased insects were highly purified by Urografin density gradient centrifugation. Antheraea eucalypti cells were inoculated with the purified spores primed with 0.1 n KOH solution to start a continuous propagation of N. bombycis in cell culture. The first increase in the number of infected A. eucalypti cells was observed at 48 hr postinoculation, and it was caused by the secondary infective forms of N. bombycis. The secondary infective forms were produced during the course of sporoblast differentiation. The parasites in cell cultures divided synchronously until 36 hr postinoculation. Mature spores were observed initially 6 days postinoculation at 27°C. The infected cultures were subcultured extensively for more than 1 year with the addition of healthy A. eucalypti cells. 相似文献