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Junichi Ishihara Nagahiro Saijo Yasutsuna Sasaki Hidehiko Nakano Akira Ozaki Hidenobu Takahashi Masanori Sakurai Kazuhiko Nakagawa Masaaki Iigo Fumihiko Kanzawa Akio Hoshi Weon Seon Hong James R. Jett Terumi Takahashi 《Cancer immunology, immunotherapy : CII》1987,24(3):185-189
Summary The antitumor effect of recombinant human tumor necrosis factor (rH-TNF) on two clones of rat fibrosarcoma with different metastatic potential to lymph nodes was examined. The colony formation of clone A, which has high metastatic potential, was completely inhibited by continuous exposure to rH-TNF at 50 U/ml. In contrast, colony formation of clone G, which has low metastatic potential, was not inhibited by high concentrations of rH-TNF (10,000 U/ml). The inhibitory effect of rH-TNF on colony formation by clone A was also observed with a 1-h exposure to rH-TNF. This effect was time and concentration dependent, as determined by the colony assay, 3H-thymidine uptake assay, and 51Cr-release assay. 3H-thymidine and 3H-uridine uptake per cell of clone A exposed to rH-TNF was not decreased. This suggests that the mechanisms of the antitumor effect of rH-TNF were not due to inhibition of DNA and RNA synthesis of tumor cells. In vivo growth and lymph node metastases of clone A inoculated i.p. to Donryu strain rats were completely suppressed by 14 consecutive i.p. injections of 105 or 106 U/kg per day of rH-TNF. On the other hand the growth of clone G was not influenced by rH-TNF administration. 相似文献
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Summary Citric acid was produced using Aspergillus niger immobilized on polyurethane foam in a bubble column reactor. Most of the adsorbed cells remained on the support and, as a result, high oxygen tension was maintained during the reactor operation. However, uncontrolled growth of the pellets made continuous reactor operation difficult. The citric acid productivity obtained from 15 vol.% foam particles containing immobilized cells was 0.135 g/l per hour. This productivity of immobilized cells was almost the same as that of free cells. The oxygen level dropped to half saturation in 5 days in the immobilized cell culture in contrast to 2 days in the free cell culture. 相似文献
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Electrostatic and steric control of electron self-exchange in cytochromes c, c551, and b5.
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The ionic strength dependence of the electron self-exchange rate constants of cytochromes c, c551, and b5 has been analyzed in terms of a monopole-dipole formalism (van Leeuwen, J.W. 1983. Biochim. Biophys. Acta. 743:408-421). The dipole moments of the reduced and oxidized forms of Ps. aeruginosa cytochrome c551 are 190 and 210 D, respectively (calculated from the crystal structure). The projections of these on the vector from the center of mass through the exposed heme edge are 120 and 150 D. For cytochrome b5, the dipole moments calculated from the crystal structure are 500 and 460 D for the reduced and oxidized protein; the projections of these dipole moments through the exposed heme edge are -330 and -280 D. A fit of the ionic strength dependence of the electron self-exchange rate constants gives -280 (reduced) and -250 (oxidized) D for the center of mass to heme edge vector. The self-exchange rate constants extrapolated to infinite ionic strength of cytochrome c, c551, and b5 are 5.1 x 10(5), 2 x 10(7), and 3.7 x 10(5) M-1 s-1, respectively. The extension of the monopole-dipole approach to other cytochrome-cytochrome electron transfer reactions is discussed. The control of electron transfer by the size and shape of the protein is investigated using a model which accounts for the distance of the heme from each of the surface atoms of the protein. These calculations indicate that the difference between the electrostatically corrected self-exchange rate constants of cytochromes c and c551 is due only in part to the different sizes and heme exposures of the two proteins. 相似文献
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T C Madhok C C Chao S G Matta A Hong B M Sharp 《Biochemical and biophysical research communications》1989,165(1):151-157
Polyclonal antibodies were raised against a synthetic decapeptide (designated S3) predicted from a segment of the alpha-3 subunit cDNA (amino acid residues 130-139) encoding the rat brain nicotinic cholinergic receptor. This segment was selected because it may be proximate to the nicotine/acetylcholine-binding site of the receptor (1). By radioligand binding assays and sucrose density gradient centrifugation, these monospecific antibodies were shown to inhibit the binding of [3H]nicotine to both the large molecular weight rat brain receptor (240 kDa) and to an SDS-disaggregated nicotine-binding subunit species (80 kDa), in a dose-dependent manner. The neutralizing effect of the anti-S3 antibodies supports the view that this region of the protein is closely related to the agonist binding site. 相似文献
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Summary Electron microscopic studies revealed that major cytological changes in the cortical cells of poplar (Populus euramericana cv. gelrica) began to occur in early September in conjunction with the metabolic transition from the growing to the wintering stage. During this transition, the cells became temporarily rich in endoplasmic reticulum, polysomes and vesicles. As the conspicuous formation of organelles progressed, the large vacuoles became smaller and filled with osmiophilic materials. Undefined organelles (protein-lipid bodies) also increased in number. From late October until March, organelles involved in protein synthesis were sparsely distributed in the cells, indicating that the number of these organelles is probably linked to the seasonal cycle of protein synthesis. In early February, after release from dormancy, fusion of vacuoles proceeded in the cells. The inclusion of organelles and a gradual decrease in the amount of osmiophilic materials in the vacuoles occurred at this stage. Subsequently, the structure of the cells continued to undergo changes to accommodate growth, which occurred in early May. 相似文献
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人体小卫星DNA探针的制备 总被引:3,自引:2,他引:1
根据人体小卫星DNA核心顺序,化学合成长23碱基寡核苷酸探针,筛选人体基因组文库,旨在获得能用作遗传分析探针的小卫星顺序。结果得到15个含小卫星的阳性重组子。随机取其一(C_(35.9))作探针,试做群体分析。所有个体均可检出多条杂交带。其中某些带具有多态性。在一定检测条件下,检出的DNA图谱在有限的个体内具有个体特异性。结果表明筛选文库得到的小卫星顺序可用于小卫星多态性的检测。其它小卫星探针的筛选和应用性研究正在进行。 相似文献