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1.
Hitoshi Sawada Hideyoshi Yokosawa Shin-Ichi Ishii Motonori Hoshi 《Molecular reproduction and development》1982,5(3):291-301
The presence of a protease has been demonstrated in sperm of the solitary ascidian, Halocynthia roretzi, by using t-butyloxycarbonyl-L-Val-L-Pro-L-Arg-4-methylcoumaryl-7-amide (Boc-Val-Pro-Arg-MCA) and other arginyl or lysyl MCA derivatives as substrates. Several properties of the enzyme were investigated in a crude extract. The activity had a pH optimum near 8.0 and was enhanced by the addition of CaCl2. The Km value of 87μM was determined for Boc-Val-Pro-Arg-MCA under the optimal conditions. An apparent molecular weight was estimated to be 35,000 by gel filtration. The enzyme was inhibited with diisopropyl fluorophosphate, leupeptin, antipain, p-aminobenzamidine, Val-Pro-Arg-CH2Cl, and soybean trypsin inhibitor, but scarcely inhibited with chymostatin, elastatinal, p-chloromercuribenzoic acid, tosyl-Lys-CH2Cl, and tosyl-Phe-CH2Cl. Boc-Val-Pro-Arg-MCA, the most susceptible of the substrates examined, showed the most effective inhibition against fertilization of ascidian eggs. Thus, this enzyme in ascidian sperm extract has features closely similar to mammalian acrosin [EC 3.4.21.10], and we conclude that the enzyme is involved in fertilization as one of the lysins. 相似文献
2.
Ishida Takuya Uehara Yoshitoshi Ikeya Tohru Haraguchi Takashi F. Asano Satoshi Ogino Yohei Okuda Noboru 《Limnology》2020,21(3):403-413
Limnology - Controlling phosphorous (P) loads from rice fields is important for the conservation of aquatic ecosystems, in part because P is relatively concentrated at its sources. Recently, winter... 相似文献
3.
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
4.
Hiroshi Taniguchi Takuya Tokida Hiroshi Fujita Hiraku Itikawa 《Molecular & general genetics : MGG》1989,217(2-3):317-323
Summary IndnaK7(Ts) mutant cells, scission of DNA strands occurred after temperature shift up. When cells at 30°C were labeled with [3H]-thymidine and then shifted to 46° or 49°C for 20 min, the profiles of sedimentation of thier cellular DNA in an alkaline
sucrose gradient revealed a decrease in the size of DNA to a quarter of that at 30°C in the mutant, but not in wild-type cells.
The level of manganese-containing superoxide dismutase (MnSOD) in the mutant was about twice that in wild-type cells, even
at the permissive temperature, implying increased production of superoxide radical anion, which may cleave DNA strands directly
or indirectly in the mutant. Moderate increase in the MnSOD level on temperature shift up was observed in both strains. These
results indicated that some components of the DnaK protein participate in protection of cellular membrane functions from thermal
damage resulting from elevated production of the superoxide anion radical. 相似文献
5.
6.
M Numazawa A Mutsumi K Hoshi R Koike 《Biochemical and biophysical research communications》1989,160(3):1009-1014
3-Deoxy steroids having a 4-ene system were found to be competitive inhibitors of human placental aromatase. 19-Hydroxy-4-androsten-17-one (2) potently inhibits the enzyme with an apparent Ki of 12.5 nM, but does not produce a time-dependent inactivation of the enzyme. 相似文献
7.
Atsushi Uchida Takuya Fujimoto Youich Mizutani 《Cancer immunology, immunotherapy : CII》1990,31(1):60-64
Summary During interaction with autologous tumor cells large granular lymphocytes (LGL) of cancer patients released a soluble cytotoxic factor, termed LGL-derived cytotoxic factor, which mediated lysing of autologous fresh tumor cells. The cytotoxic factor was compared with purified human recombinant cytotoxic cytokines, including tumor necrosis factor (TNF), lymphotoxin (LT), interferon (IFN) , IFN, interleukin-1 (IL-1) and IL-2. The LGL cytotoxic factor exhibited cytotoxicity against autologous and allogeneic fresh human tumor cells in an 18-h51Cr-release assay, while these target cells were resistant to lysing by any of the recombinant cytokines. Mixtures of recombinant(r) TNF, rLT, rIFN, rIFN, rIL-1 and rIL-2 were still unable to produce cytotoxic effects on fresh human tumor cells. Treatment with monoclonal and polyclonal antibodies directed against rTNF, rLT, rIFN, rIFN, or rIL-1 did not inhibit the cytotoxic activity of LGL-derived cytotoxic factor against fresh human tumor cells. Even a mixture of all the antibodies was incapable of blocking the cytolytic activity of the factor to fresh human tumor cells. Furthermore, intact LGL-mediated lysing of autologous tumor cells was not inhibited by any of the antibodies. These results may indicate that a cytotoxic factor produced by LGL in response to autologous tumor cells mediates lysing of fresh human tumor cells independently of TNF, LT, IFN, IL-1 and IL-2. 相似文献
8.
Hiroki Yamaue Hiroshi Tanimura Takuya Tsunoda Makoto Iwahashi Masaji Tani Mikiko Tamai Masaya Inoue 《Biotherapy》1990,2(3):247-259
The tumor-infiltrating lymphocytes (TILs) were cultured with interleukin 2 (IL-2) to induce the activated killer cells possessing autologous tumor-killing activity, and analysed their cell surface phenotypes and assessed anti-tumor killing activity. Furthermore, the activated TILs were transferred into 7 patients adoptively resulting in complete remission in a patient with pancreatic cancer and partial remission in another patient with gastric cancer.The cytotoxic activities of activated TILs at 3 weeks-incubation was 72 ± 15, 42 ± 26, 27 ± 21 and 25 ± 15% against K562, Daudi, KATO-III and autologous tumor, respectively. The negative selection method, indicated that the killer cells recognizing autologous tumor cells consisted of CD4- or CD8-positive T lymphocytes and CD16- or CD56-positive natural killer cells. The activated TILs could not only lyse cultured tumor cell lines, but also autologous tumor cells. 相似文献
9.
Kazuhisa Toyoda Takuya Sugahara Kunio Inouye Koji Yamada Sanetaka Shirahata Hiroki Murakami 《Cytotechnology》1990,3(2):189-197
An immunoglobulin (Ig) production stimulating factor (IPSF) for hybridomas was found in spent medium of the human B lymphoblastoid cell line, HO-323. The IPSF was purified by serial use of DEAE chromatography, ultrafiltration, gel filtration and HPLC-DEAE chromatography. Purified IPSF was estimated to be a 410 k macro molecule by gel filtration, and contained three types of isomers which were separated from each other by native polyacrylamide gel electrophoresis. All of the isomers were, however, assumed to have the same protein components by SDS polyacrylamide gel electrophoresis.The IPSF was effective for human-human and mouse-mouse hybridomas producing IgM, but not for IgG producers in the experimental condition used here. Human-human hybridoma HF10B4, cultured in IPSF-containing medium, produced 20 times more IgM than in IPSF-free medium under serum-free conditions. The IPSF showed very little proliferation stimulating activity on HF10B4 cells. 相似文献
10.
Voltage-dependent K+ currents and underlying single K+ channels in pheochromocytoma cells 总被引:11,自引:4,他引:7 下载免费PDF全文
Properties of the whole-cell K+ currents and voltage-dependent activation and inactivation properties of single K+ channels in clonal pheochromocytoma (PC-12) cells were studied using the patch-clamp recording technique. Depolarizing pulses elicited slowly inactivating whole-cell K+ currents, which were blocked by external application of tetraethylammonium+, 4-aminopyridine, and quinidine. The amplitudes and time courses of these K+ currents were largely independent of the prepulse voltage. Although pharmacological agents and manipulation of the voltage-clamp pulse protocol failed to reveal any additional separable whole-cell currents in a majority of the cells examined, single-channel recordings showed that, in addition to the large Ca++-dependent K+ channels described previously in many other preparations, PC-12 cells had at least four distinct types of K+ channels activated by depolarization. These four types of K+ channels differed in the open-channel current-voltage relation, time course of activation and inactivation, and voltage dependence of activation and inactivation. These K+ channels were designated the Kw, Kz, Ky, and Kx channels. The typical chord conductances of these channels were 18, 12, 7, and 7 pS in the excised configuration using Na+-free saline solutions. These four types of K+ channels opened in the presence of low concentrations of internal Ca++ (1 nM). Their voltage-dependent gating properties can account for the properties of the whole-cell K+ currents in PC-12 cells. 相似文献