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1.
Formation of a Tree having a Low Lignin Content 总被引:2,自引:0,他引:2
Received 30 September 2001/ Accepted in revised form 26 October 2001 相似文献
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Diabetic nephropathy (DN), a major cause of end-stage chronic renal failure, is histologically characterized by glomerulosclerosis. To investigate the molecular mechanisms of DN, it is important to establish a stable model of glomerulosclerosis in mice, because genomic manipulation techniques (such as gene destruction or transgene insertion) are well established in rodent species. In this study, we found that repeated administrations of streptozotocin led to early onset of glomerular sclerotic lesions in C57BL/6 mice, accompanied with renal dysfunction. During the natural course of DN, glomerular endothelial cells decreased at 10 weeks after the start of streptozotocin-injections, whereas myofibroblastic mesangial cells became evident. Our results provide an animal tool to elucidate the molecular mechanisms of DN, for example to investigate vascular pathology in diabetic glomerular diseases. 相似文献
4.
Tsuyoshi Akiyoshi Shinya Arinaga Hideo Tsuji 《Cancer immunology, immunotherapy : CII》1987,24(3):259-262
Summary The effects of mitomycin C (MMC) on the generation of cell-mediated cytotoxicity in primary stimulation culture of human peripheral blood mononuclear cells (PBM) with the B lymphoblastoid Raji cell line were assessed. The cell-mediated cytotoxicity induced in culture was significantly augmented when MMC was added to cultures on day –1 to day 3 for 24 h at concentrations of 2.5×10–2 g/ml and 2.5×10–3 g/ml. To identify the cell populations affected by MMC, PBM were separated by adherence to plastic after treatment with MMC for 24 h (day –1). The two populations were recombined with untreated separated cells and stimulated with antigen. The ability to develop an augmented cell-mediated cytotoxicity was associated with the adherent cell fraction of MMC-treated PBM. Therefore, the ability of MMC-treated adherent cells to produce interleukin 1 (IL 1) was examined. Significantly higher levels of IL 1 were produced by treated cells as compared to untreated adherent cells. The results appear to indicate that the selective effects of MMC on the adherent cell fraction, especially the modification of IL 1 production, may be involved in the mechanisms of MMC-induced augmented cell-mediated cytotoxicity. 相似文献
5.
Kenji Tomioka Kenji Yamada Shinya Yokoyama Yoshihiko Chiba 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1991,169(3):291-298
The coupling mechanism between the bilaterally paired optic lobe circadian pacemakers in the cricket Gryllus bimaculatus was investigated by recording locomotor activity, under constant light or constant red light, after the optic nerve was unilaterally severed.
These results suggest that the 2 optic lobe pacemakers weakly couple to one another and that the cricket maintains a stable temporal structure in its behavior through the phase-dependent mututal inhibition of activity and the phase-dependent freerunning period modulation. 相似文献
1. | The majority (about 70%) of the animals showed a locomotor rhythm with 2 rhythmic components; one freerunning with a period of 25.33 ± 0.41 (SD) h and the other with 24.36 ± 0.37 (SD) h under constant light (Fig. 3A). |
2. | Removal of the intact side optic lobe abolished the longer period component (Fig. 4A), while the operation on the operated side caused a reverse effect (Fig. 4B), indicating that the longer and the shorter period components are driven by the pacemaker on the intact and the operated side, respectively. |
3. | The activity driven by a pacemaker was inhibited during the subjective day of the contralateral pacemaker (circadian time 0–10, Fig. 5). |
4. | The freerunning periods of the two components were not constant but varied as a function of the mutual phase angle relationship (Figs. 3A, 7, 8). |
6.
Cloning and expression of subtilisin amylosacchariticus gene 总被引:7,自引:0,他引:7
T Yoshimoto H Oyama T Honda H Tone T Takeshita T Kamiyama D Tsuru 《Journal of biochemistry》1988,103(6):1060-1065
The gene encoding subtilisin Amylosacchariticus from Bacillus subtilis var. amylosacchariticus was isolated and the entire nucleotide sequence of the coding sequence was determined. The deduced amino acid sequence revealed an N-terminal signal peptide and pro-peptide of 106 residues followed by the mature protein comprising 275 residues. There were discrepancies in 10 amino acids between the sequence elucidated from the nucleotide sequence and the published protein sequence (Kurihara et al. (1972) J. Biol. Chem. 247, 5619-5631). The nucleotide sequence was highly homologous to that of subtilisin E gene from B. subtilis 168, with discrepancies at 12 nucleotides out of 1,426 nucleotides we sequenced. Ten of them were found in mature subtilisin coding sequence, which resulted in two amino acid changes and another one was in the putative promoter region between two genes. The productivity of subtilisin in culture broth of B. subtilis var. amylosacchariticus was much higher than that of B. subtilis 168. The enzyme gene was inserted in a shuttle vector pHY300PLK, with which B. subtilis ISW1214 was transformed. The proteolytic activity found in the culture broth of the transformed bacterium was 20- and 4-fold higher than those of the host strain and B. subtilis var. amylosacchariticus, respectively. Subtilisin Amylosacchariticus was easily purified to a crystalline form from culture filtrate of cloned B. subtilis, after a single step of chromatography on CM-cellulose. 相似文献
7.
Studies on prolyl endopeptidase from shakashimeji (Lyophyllum cinerascens): purification and enzymatic properties 总被引:1,自引:0,他引:1
High prolyl endopeptidase (post-proline cleaving enzyme) [EC 3.4.21.26] activity was detected in fruit bodies of shakashimeji (Lyophyllum cinerascens), tsukuritake (mushroom: Agaricus bisporus), hirohachichitake (Lactarius hygrophoroides), and yaburebenitake (Russula lepida) which belong to the genus Basidiomycetes. Cell-free extract of shakashimeji showed high activities of proline iminopeptidase and arylamidase as well as prolyl endopeptidase. The prolyl endopeptidase was purified from the extract of shakashimeji by sequential chromatographies on DEAE-Toyopearl, DEAE-Sephadex and hydroxyapatite, and high-performance liquid chromatography with a DEAE-5PW column. The purified enzyme was homogeneous as judged by disc gel electrophoresis. The enzyme was most active at pH 6.8 as checked with Z-Gly-Pro-beta-naphthylamide as a substrate and was stable in the range of pH 5.8-7.4. The isoelectric point of the enzyme was 5.2 and the molecular weight was estimated to be 76,000 by gel filtration on Sephadex G-150 and by sodium dodecyl sulfate (SDS) gel electrophoresis, suggesting that the enzyme was a monomer. The enzyme was completely inhibited by diisopropyl fluorophosphate (DFP), Z-Gly-Pro-CH2Cl, and Z-Pro-prolinal, while it was not inhibited by p-chloromercuribenzoate (PCMB), phenylmethylsulfonyl fluoride (PMSF), or metal chelators. It was estimated that at least five subsites were concerned with the enzyme-substrate binding. Among them, the S1, S2, and S1' sites showed high stereospecificity, as in mammalian, microbial, and plant enzymes. The enzyme hydrolyzed TRH at the carboxyl side of the proline residue. The mushroom enzyme, that was sensitive to DFP, Z-Pro-prolinal, and Z-Gly-Pro-CH2Cl, but not to PCMB, were quite similar in characteristics to the Flavobacterium enzyme.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
8.
Cell-surface hydrophobicity of Candida species as determined by the contact-angle and hydrocarbon-adherence methods 总被引:3,自引:0,他引:3
S Minagi Y Miyake Y Fujioka H Tsuru H Suginaka 《Journal of general microbiology》1986,132(4):1111-1115
Cell-surface hydrophobicities of six Candida species were studied by two methods: measurement of the contact angle, and partitioning with aqueous-hydrocarbon (n-octane, n-hexadecane and p-xylene) mixtures. C. tropicalis, C. glabrata and C. krusei adhered better to the hydrocarbons than did C. albicans, C. stellatoidea and C. parapsilosis. Contact angles for the less adherent species were smaller than those for the more adherent species. Thus the two methods gave results that were similar overall and indicated that C. tropicalis, C. glabrata and C. krusei have greater cell-surface hydrophobicities than C. albicans, C. stellatoidea and C. parapsilosis. 相似文献
9.
The inhibitory effects of proline-containing peptides and their derivatives on prolyl endopeptidases from Flavobacterium meningosepticum and bovine brain were compared. Replacement of the carboxyl terminal proline in N-blocked peptides with prolinal resulted in remarkable decreases in Ki values for both prolyl endopeptidases. Further reduction of the prolinal to prolinol led to a decrease in their inhibitory effects. Z-Pro-, Z-Val-, and Suc-Pro-prolinals were similarly inhibitory for both the enzymes with Ki values of nM order. However, the inhibitory effects of Z-Pyr-prolinal and Boc-Pro-prolinal on these enzymes were significantly distinguished: they strongly inhibited the mammalian prolyl endopeptidase with Ki values of nM order, while the Ki values of these compounds for the microbial enzyme were only of microM order. These results suggest that there are some structural differences in the S2 and S3 subsites between the two enzymes, though their substrate specificities are apparently indistinguishable. 相似文献