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1.
2.
Induction of ornithine decarboxylase in guinea-pig lymphocytes. Synergistic effect of diacylglycerol and calcium 总被引:4,自引:0,他引:4
Calmodulin antagonists, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), N-(6-aminohexyl)-1-naphthalenesulfonamide (W-5) and trifluoperazine inhibited ornithine decarboxylase induction in lymphocytes activated with phytohemagglutinin or inophore A23187. W-7, a more potent calmodulin antagonist than W-5, suppressed ornithine decarboxylase induction in a higher extent than did W-5. These results suggest that calmodulin may play an important role in ornithine decarboxylase induction in the activated lymphocytes. However, the extent of ornithine decarboxylase induction was greater in cells pretreated with Clostridium phospholipase C and then incubated with ionophore A23187 than in cells incubated with ionophore A23187 without the pretreatment. Moreover, combined treatment of cells with ionophore A23187 and tumor promotor, phorbol 12-myristate 13-acetate, caused synergistic induction of ornithine decarboxylase activity. These results, taken together, suggest that both activations of Ca2+-activated phospholipid-dependent protein kinase by diacylglycerol and of calmodulin-dependent function resulted from an elevation of cytosolic Ca2+ concentration may operate in the induction of ornithine decarboxylase in the activated lymphocytes. 相似文献
3.
Keisuke Kohmoto Kazuya Akimitsu Tetsuyuki Kohguchi Hiroshi Otani John M. Gardner 《Plant cell reports》1986,5(1):54-56
Amberlite XAD-7, a nonionic polyacrylate adsorbent, was found to be a very effective protectant for isolating mitochondria from tissues rich in oils and phenolics. Physiologically active, well-coupled mitochondria were successfully prepared from young green leaf tissues of citrus, apple, pear and tobacco.Abbreviations DNP
2,4-dinitrophenol
- CCCP
carbonyl cyanide m-chlorophenylhydrazone
- BSA
bovine serum albumin
- PVP
polyvinylpyrrolidone 相似文献
4.
Cortices of unfertilized sea urchin eggs can be isolated in suspension and will discharge the attached cortical vesicles (CVs) in response to calcium. We describe a simple turbidometric assay for monitoring the Ca2+-induced discharge of these vesicles and also compare the discharge of vesicles isolated in a high salt medium (primarily KCl) with a medium more closely simulating the internal milieu of the cell (primarily potassium gluconate and glycine). Discharge in response to calcium is similar in both media, requiring approximately 6 μM calcium for one-half maximal discharge. There are, however, significant differences in morphology and protein composition of the two types of preparations (more proteins present in the glycine cortices) and also in the rate of discharge of the vesicles in response to calcium (KCl cortices with 6 sec as opposed to 30 sec in the glycine cortices). The glycine cortices gradually lose their ability to respond to calcium but retention of calcium sensitivity is considerably aided by inclusion of ATP in the media; ATP has no apparent effect on discharge of the KCl cortices. The glycine cortices, as opposed to the KCl cortices, exhibited variation in calcium sensitivity during the breeding season and in the number of vesicles which would not break down in response to added calcium (referred to as refractory vesicles). The question of which type of cortex preparation most closely simulates the in vivo situation is discussed, and the view is presented that the glycine cortices most closely resemble the in vivo situation. 相似文献
5.
The physical characteristics of a mutant, R(M201-2), capable of conferring high and stable ampicillion resistance was analyzed. The R(M201-2) and its parent R-factor deoxyribonucleic acid (DNA) could be isolated as an extrachromosomal and covalently closed circular form. Their buoyant densities were both 1.712 g/cm(3), and their molecular weights were about 82 x 10(6) and 64 x 10(6), respectively, when measured by CsCl and sucrose density gradient analyses. The contour lengths by electron microscopy were 35.9 +/- 0.6 and 31.0 +/- 0.6 mum, respectively. By using the extracted R-factor DNA, the mutant and parent characters were transformable to another Escherichia coli strain. The mutant R factor showed an increased amount of DNA even after conjugal transfer to Proteus. An increase in the size of R-factor DNA was thus considered to be the cause of the high level of ampicillin resistance. 相似文献
6.
7.
Midori Hiramatsu Kumiko Haba Rei Edamatsu Hajime Hamada Akitane Mori 《Neurochemical research》1989,14(3):249-251
The effect of a Chinese herbal medicine Sho-saiko-to-go-keishi-ka-shakuyaku-to (TJ-960) on the brain choline acetyltransferase (CAT) activity was studied in adult (3.5 months of age) and aged (24 months of age) rats. After oral administration of 5% TJ-960 solution for 3 months, CAT activity in the hippocampus, pons-medulla oblongata and striatum of aged rats was significantly lower than that of adult rats. CAT activity in the cerebellum, however, was significantly higher in the aged rats, as compared to the adult rats. TJ-960 significantly increased CAT activity in the hippocampus and striatum of aged rats, but did not affect the activity of the enzyme in the adult rat brain. 相似文献
8.
Determination of the entire nucleotide sequence of the aphid 28S ribosomal RNA gene (28S rDNA) revealed that it is 4,147 by
in length with a G + C content of 60.3%. Based on the nucleotide sequence, we constructed a presumed secondary-structure model
of the aphid 28S rRNA which indicated that the aphid 28S rRNA is characterized by the length and high G + C content of its
variable regions. The G + C content of the aphid's variable regions was much higher than that of the entire sequence of the
28S rRNA, which formed a striking contrast to those ofDrosophila with the G + C content much lower than the entire 28S molecule. In this respect, the aphid 28S rRNA somewhat resembled those
of vertebrates. This is the third report of a complete large-subunit rRNA sequence from an arthropod, and the first 28S rRNA
sequence for a nondipterous insect.
Correspondence to: H. Ishikawa 相似文献
9.
Role of cell wall of groundnut roots in solubilizing sparingly soluble phosphorus in soil 总被引:2,自引:0,他引:2
Groundnut showed a superior ability to take up P from a soil with low P fertility compared with sorghum and soybean. This
ability was not related to its better root development or production of root exudates capable of solubilizing iron-and aluminum-bound
P. In efforts to determine the role of roots per se, we found that root cell walls from groundnut showed a higher P-solubilizing
activity than those from soybean or sorghum. This finding corresponds well with observations in field and pot experiments
using a soil with low P availability. The reaction site of P-solubilizing activity is stable against heating and enzyme digestion
by cellulase and pectinase. This is probably the first evidence to demonstrate that cell walls of plant roots are involved
in P-solubilizing activity. ei]Section editor: H Marschner (deceased 21 September 1996) 相似文献
10.
Myosin molecules contacting an actin filament in the presence of ATP were found to regulate the filamental fluctuations due to ATP hydrolysis in a communicative manner along the filament. As an evidence of the occurrence of the communication, ATP-activated fluctuating displacements of the filament in the direction perpendicular to its longitudinal axis were identified to propagate at a finite velocity not less than about 0.2 μm/s unidirectionally along the filament. 相似文献