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2.
H Murofushi A Ikai K Okuhara S Kotani H Aizawa K Kumakura H Sakai 《The Journal of biological chemistry》1988,263(25):12744-12750
Kinesin was purified from bovine adrenal medulla. The sedimentation coefficient was 8.8 S. Sedimentation equilibrium ultracentrifugation studies showed the molecular weight of kinesin to be 300,000. The calculated axial ratio was 1:16. The Stokes radius was estimated to be 8.9 nm by gel filtration. Circular dichroism showed the alpha-helix content to be about 50%. Purified kinesin preparation contained a major polypeptide with a molecular weight of 120,000 and minor ones with molecular weights of 71,000, 68,000, and 65,000. Bovine adrenal kinesin had an ATPase activity which was stimulated severalfold by microtubules to a specific activity of about 0.1 mumol/min.mg. Kinesin molecules adsorbed to a glass slide promoted the movement of microtubules on the glass surface at a rate of about 0.5 micron/s. Immunostaining of EBTr (bovine embryonic trachea fibroblast) cells and bovine adrenal chromaffin cells in interphase with an affinity-purified antibody against the major polypeptide of kinesin showed that some kinesin was located on microtubules and the rest distributed throughout the cytoplasm in a diffuse manner. EBTr cells in mitotic phase gave a staining pattern showing that kinesin was present throughout the cytoplasm with higher concentration in the region of mitotic apparatus. 相似文献
3.
1. Effects of imidazole compounds and guanabenz on the stimulus-evoked release of catecholamine (CA) were studied in cultured bovine adrenal chromaffin cells. 2. Clonidine, oxymetazoline, phentolamine, chlorpheniramine, and guanabenz inhibited acetylcholine (ACh)-evoked CA release in a dose-dependent manner, but not high K(+)-evoked release. 3. The inhibition by these compounds was not antagonized by nonimidazole and nonguanidine alpha 2-antagonists (yohimbine and phenoxybenzamine) but was significantly antagonized by tolazoline (imidazole alpha 2-antagonist) and cimetidine (imidazole H2-antagonist). Moreover, tolazoline by itself augmented the ACh-evoked, but not the high K(+)-evoked, CA release. 4. Although chlorpheniramine and cimetidine are antagonists for H1 and H2 histaminergic receptors, the site of action for these compounds in our results seemed to differ from the histamine receptors. 5. These results suggest that the inhibitory action of imidazole compounds and guanabenz on ACh-evoked CA release in adrenal chromaffin cells is mediated through an imidazole receptor. Adrenal chromaffin cells may contain an endogenous clonidine-displacing substance (CDS) which has been found in adrenal gland and brain as an endogenous ligand for imidazole receptors. Thus, CDS may have a regulatory role in the stimulus-secretion coupling in these cells. 相似文献
4.
Nobuyuki Sasakawa Konosuke Kumakura Satoshi Yamamoto Ryuichi Kato 《Life sciences》1983,33(20):2017-2024
Effects of N-(6-aminohexyl)-5-chloro-1-naph-thalenesulfonamide (W-7), a calmodulin antagonist, on catecholamine (CA) release and 45Ca2+ uptake were studied using cultured bovine adrenal chromaffin cells. W-7 inhibited the carbamylcholine (CCh)-evoked CA release and 45Ca2+ uptake in a concentration-dependent manner. The inhibitory effect of W-7 on CCh-evoked CA release was not overcome either by an increase in extracellular calcium or CCh concentration. Although W-7 inhibited the high K+-evoked CA release and 45Ca2+ uptake, potency of the drug was approximately 50–100 fold less than when inhibiting the CCh-evoked CA release and 45Ca2+ uptake. The inhibitory effects of W-7 were observed both in norepinephrine release and epinephrine release. Moreover, W-7 inhibited the CCh-evoked 45Ca2+ efflux. These results suggest that the inhibition of CA release by W-7 in adrenal chromaffin cells is mainly due to its inhibition of calcium uptake. W-7 may influence the linkage between acetylcholine-receptor and calcium uptake with higher potency than depolarization-dependent calcium entry. 相似文献
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6.
Thermolysin (Bacillus thermoproteolyticus neutral proteinase, EC 3.4.24.4) has been immobilized by radiation polymerization of hydrophilic and hydrophobic monomers, and its properties, such as enzyme activity, thermal stability and durability, have been studied. The activity of the immobilized enzymes increased with an increase in the hydrophilicity of the polymer matrix and with a decrease in monomer concentration. Immobilization with hydrophilic monomers increased the thermal stability of the enzymes, but the thermal stability of the enzymes immobilized with hydrophobic monomers was comparable with that of native enzymes. The durability of the immobilized enzymes was examined by continuous hydrolysis of casein; enzymes immobilized with a high concentration (90%) of hydrophilic monomers appeared to be stabilized and could be used for long times. 相似文献
7.
Enzyme immobilization was studied by means of radiation-induced polymerization of hydrophobic glass-forming monomers at low temperatures. The polymerized hydrophobic composite was generally obtained in microspheric form. Enzymatic activity showed little decrease with repeated use in these systems. The particle size of the microsphere increased with increasing monomer concentration, and activity yield had a maximum at an optimum monomer concentration. Immobilization by copolymerization of hydrophilic and hydrophobic comonomers was also investigated and a maximum activity yield was found at a certain monomer concentration. A model scheme for immobilization at low temperatures was proposed and discussed. 相似文献
8.
Hisato Kobayashi Eikichi Yanagisawa Akihiko Sakashita Naoko Sugawara Shiori Kumakura Hidehiko Ogawa Hidenori Akutsu Kenichiro Hata Kazuhiko Nakabayashi Tomohiro Kono 《Epigenetics》2013,8(6):635-651
Artificial induction of active DNA demethylation appears to be a possible and useful strategy in molecular biology research and therapy development. Dimethyl sulfoxide (DMSO) was shown to cause phenotypic changes in embryonic stem cells altering the genome-wide DNA methylation profiles. Here we report that DMSO increases global and gene-specific DNA hydroxymethylation levels in pre-osteoblastic MC3T3-E1 cells. After 1 day, DMSO increased the expression of genes involved in DNA hydroxymethylation (TET) and nucleotide excision repair (GADD45) and decreased the expression of genes related to DNA methylation (Dnmt1, Dnmt3b, Hells). Already 12 hours after seeding, before first replication, DMSO increased the expression of the pro-apoptotic gene Fas and of the early osteoblastic factor Dlx5, which proved to be Tet1 dependent. At this time an increase of 5-methyl-cytosine hydroxylation (5-hmC) with a concomitant loss of methyl-cytosines on Fas and Dlx5 promoters as well as an increase in global 5-hmC and loss in global DNA methylation was observed. Time course-staining of nuclei suggested euchromatic localization of DMSO induced 5-hmC. As consequence of induced Fas expression, caspase 3/7 and 8 activities were increased indicating apoptosis. After 5 days, the effect of DMSO on promoter- and global methylation as well as on gene expression of Fas and Dlx5 and on caspases activities was reduced or reversed indicating down-regulation of apoptosis. At this time, up regulation of genes important for matrix synthesis suggests that DMSO via hydroxymethylation of the Fas promoter initially stimulates apoptosis in a subpopulation of the heterogeneous MC3T3-E1 cell line, leaving a cell population of extra-cellular matrix producing osteoblasts. 相似文献
9.
Asaka Takahashi Tsuyoshi Yamada Yohei Uchiyama Satomi Hayashi Kei Kumakura Hitoe Takahashi 《Bioscience, biotechnology, and biochemistry》2013,77(9):1512-1517
2-[3-(2-Thioxopyrrolidin-3-ylidene)methyl]-tryptophan (TPMT) is a yellow pigment of salted radish roots (takuan-zuke) derived from 4-methylthio-3-butenyl isothiocyanate (MTBITC), the pungent component of radish roots. Here, we prepared salted radish and analyzed the behavior of the yellow pigment and related substances in the dehydration process and long-term salting process. All salted radish samples turned yellow, and their b* values increased with time and temperature. The salted radish that was sun-dried and pickled at room temperature turned the brightest yellow, and the generation of TPMT was clearly confirmed. These results indicate that tissue shrinkage due to dehydration, salting temperature, and pH play important roles in the yellowing of takuan-zuke. 相似文献
10.
In teleosts, estradiol-17beta (E2) is an important hormone responsible for oocyte development. To elucidate the molecular mechanisms underlying E2 biosynthesis, we characterized the structure of red seabream (Pagrus major) cytochrome P450 aromatase (P450(arom)) that is directly involved in E2 biosynthesis and found changes in mRNA levels of P450(arom) during oocyte development induced by implantation of gonadotropin-releasing hormone analogue. A cDNA clone encoding P450(arom) is 1779 base pairs in length and encodes a protein of 519 amino acids in length, with a calculated molecular weight of 58.9 kDa. Northern blot analysis showed that P450(arom) mRNA levels increased gradually from Day 8, when oocytes reached the secondary yolk globule stage, and were maintained at high levels at the day of spawning (Day 15). The P450(arom) mRNA levels increased in association with an increase of the gonadosomatic index (gonad weight/body weight x 100%), serum E2, and P450(arom) enzyme activity (in vitro conversion of testosterone to E2 in the ovarian fragments). Furthermore, an increase in mRNA levels of the LHbeta, but not FSHbeta, correlated with increased P450(arom) mRNA levels during the course of ovarian development. In addition, the levels of P450(arom) mRNA increased in isolated ovarian follicles during the course of vitellogenic oocyte growth and became undetectable in follicles at the migratory nucleus and the mature stages. These findings, together with those of the previous studies, suggest that LH, not FSH, may regulate E2 biosynthesis via increased levels of P450(arom) mRNA during oocyte development of red seabream. 相似文献